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ACCEPTED
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Method and apparatus of recording data in the optical recording medium
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An optical recording medium record/playback apparatus manages defective areas in a rewritable optical recording medium. A linear replacement control (LRC) bit is added to a secondary defective list (SDL) entry to discriminate defective block information listed in the SDL entry, according to a linear replacement algorithm, from defective block information listed at the SDL entry, according to a skipping algorithm. This allows the apparatus to transmit correct information to a host. When a defective block requiring a new replacement block is found during recording or playing back data and the spare area is full, instead of carrying out the linear replacement, the LRC bit is set in the SDL entry, along with the location information of the defective block. This indicates that the SDL entry was made when the spare area was full. Thus, data is not written in, or read from, the defective block.
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1. A data structure for defect management information recorded on an optical recording medium, or to be recorded or reproduced on or from an optical recording medium by a reproducing or recording device, wherein the defect management information includes at least one of first, second or third entries, the first entry indicates that a defective block is replaced with a spare block and a position of the spare block is designated, the second entry indicates that a defective block is not replaced and a position of a spare block is designated or maintained, and the third entry indicates that a defective block is not replaced and a position of a spare block is not designated. 2. The data structure of claim 1, wherein the first, second or third entries are indicated by an indication information which indicates whether or not a defective block is replaced with a spare block and a position information which indicates the position of a spare block within a spare area. 3. The data structure of claim 1, wherein the first entry is generated regarding the defective block when non real time data is recorded or reproduced and/or a spare area is not full. 4. The data structure of claim 3, wherein if the first entry has been generated and recorded during previous recording or producing, the first entry is changed to the second entry regarding the defective block when the current recording or reproducing is real time data, wherein the position of spare block is maintained. 5. The data structure of claim 1, wherein if the second entry has been generated regarding the defective block when current real time data is recorded on an area of the optical recording medium where previous non real time data has been recorded. 6. The data structure of claim 4, wherein when the current real time data is recorded or reproduced, the real time data is not recorded or reproduced on or from a defective block and recorded or reproduced on or from next available block. 7. The data structure of claim 1, wherein the third entry is generated regarding the defective block when real time data is recorded or produced. 8. The data structure of claim 7, wherein data is not recorded or reproduced on or from defective block and recorded or reproduced on or from next available block when the real time data is recorded or reproduced. 9. The data structure of claim 1, wherein the third entry is generated regarding the defective block when a spare area is full. 10. The data structure of claim 1, wherein the third entry is generated regarding the defective block when the spare area is full and non real time data is recorded or reproduced. 11. The data structure of claim 10, wherein if the third entry has been generated and recorded during previous recording or reproducing, the third entry is changed to the first entry regarding the defective click when the current recording or reproducing is non real time data and a spare area is assigned. 12. The data structure of claim 1, wherein the first to third entries further indicate a position of defective block. 13. The data structure of claim 1, wherein if the first entry has been generated and recorded during previous recording or reproducing, the first entry is updated to the second entry regarding the defective block when the current recording or reproducing is real time data, wherein the position of spare block is maintained. 14. The data structure of claim 1, wherein if the third entry has been generated and recording during previous recording or reproducing, the third entry is updated to the first entry regarding the defective block when the current recording or producing is non real time data and a spare area is assigned.
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The present application is a divisional of co-pending U.S. patent application Ser. No. 09/359,646 filed on Jul. 26, 1999 for which priority is claimed under 35 U.S.C. § 120; and the present application claims priority of Patent Application No. 1998-30320 filed in the Republic of Korea on Jul. 28, 1998; Patent Application No. 1998-31406 filed in the Republic of Korea on Aug. 1, 1998; and Patent Application No. 1998-39797 filed in the Republic of Korea on Sep. 24, 2998, under 35 U.S.C. § 119. The entire contents of each of these applications are herein fully incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium which allows rewriting, and more particularly to a method and apparatus of recording data in the optical recording medium, wherein defect areas can be managed. 2. Description of Related Art An optical storage medium is generally divided into a read only memory (ROM), a write once read many (WORM) memory into which data can be written one time, and rewritable memories into which data can be written several times. Rewritable optical storage mediums, i.e. optical discs, include rewritable compact discs (CD-RW) and rewritable digital versatile discs (DVD−RW, DVD-RAM, DVD+RW). The operations of writing and playing back data in a rewritable optical disc may be repeated. This repeated process alters the ratio of storage layers for recording data into the optical disc from the initial ratio. Thus, the optical discs lose its characteristics and generate an error during recording/playback. This degradation is indicated as a defective area at the time of formatting, recording on or playing back from an optical storage medium. Also, defective areas of a rewritable optical disc may be caused by a scratch on its surface, particles of dirt and dust, or errors during manufacture. Therefore, in order to prevent writing into or reading out of the defective area, management of such defective areas is necessary. FIG. 1 shows a defect management area (DMA) in a lead-in area and a lead-out area of the optical disc to manage a defect area. Particularly, the data area is divided into a plurality of zones for the defect area management, where each zone is further divided into a user area and a spare area. The user area is where data actually written and the spare area is used when a defect occurs in the user area. There are four DMAs in one disc, e.g. DVD-RAM, two of which exist in the lead-in area and two exist in the lead-out area. Because managing defective areas is important, the same contents are repeatedly recorded in all four DMAs to protect the data. Each DMA comprises two blocks of 32 sectors, where one block comprises 16 sectors. The first block of the DMA, called a DDS/PDL block, includes a disc definition structure (DDS) and a primary defect list (PDL). The second block of the DMA, called an SDL block, includes a secondary defect list (SDL). The PDL corresponds to a primary defect data storage and the SDL corresponds to a secondary defect data storage. The PDL generally stores entries of defective sectors caused during the manufacture of the disc or identified when formatting a disc, namely initializing and re-initializing a disc. Each entry is composed of an entry type and a sector number corresponding to a defective sector. The SDL lists defective areas in block units, thereby storing entries of defective blocks occurring after formatting or defective blocks which could not be stored in the PDL during the formatting. As shown in FIG. 2, each SDL entry has an area for storing a sector number of the first sector of a block having defective sectors, an area for storing a sector number of the first sector of a block replacing the defective block, and reserved areas. Also, each SDL entry is assigned a value of 1 bit for forced reassignment marking (FRM). A FRM bit value of 0 indicates that a replacement block is assigned and that the assigned block does not have a defect. A FRM bit value of 1 indicates that a replacement block has not been assigned or that the assigned replacement block has a defect. Thus, to record data in a defective block listed as a SDL entry, a new replacement block must be found to record the data. Accordingly, defective areas, i.e. defective sectors or defective blocks, within the data area are replaced with normal or non-defective sectors or blocks by a slipping replacement algorithm and a linear replacement algorithm. The slipping replacement is utilized when a defective area or sector is recorded in the PDL. As shown in FIG. 3A, if defective sectors m and n, corresponding to sectors in the user area, are recorded in the PDL, such defective sectors are skipped to the next available sector. By replacing the defective sectors by subsequent sectors, data is written to a normal sector. As a result, the user area into which data is written slips and occupies the spare area in the amount equivalent to the skipped defective sectors. The linear replacement is utilized when a defective block is recorded in the SDL or when a defective block is found during playback. As shown in FIG. 3B, if defective blocks m and n, corresponding to blocks in either the user or spare area, are recorded on the SDL, such defective blocks are replaced by normal blocks in the spare area and the data to be recorded in the defective block are recorded in an assigned spare area. To achieve the replacement, a physical sector number (PSN) assigned to a defective block remains, while a logical sector number (LSN) is moved to the replacement block along with the data to be recorded. Linear replacement is effective for non real-time processing of data. For convenience, a data which does not require real time processing is hereinafter called a personal computer (PC)-data. If a replacement block listed in the SDL is found to be defective, a direct pointer method is applied to the SDL listing. According to the direct pointer method, the defective replacement block is replaced with a new replacement block and the SDL entry of the defective replacement block is modified into a sector number of the first sector of the new replacement block. FIG. 4A shows a procedure to manage a defective block found while writing or reading data into or from the user area. FIGS. 4B˜4D show embodiments of SDL entries generated according to the linear replacement algorithm. Each SDL entry has, in order, a FRM, a sector number of the first sector of the defective block, and a sector number of the first sector of the replacement block. For example, if the SDL entry is (1, blkA, 0) as shown in FIG. 4B, a defective block has been newly found during the reproduction and is listed in the SDL. This entry indicates that a defect occurs in block blkA and that there is no replacement block. The SDL entry is used to prevent data from being written into the defective block in the next recording. Thus, during the next recording, the defective block blkA is assigned a replacement block according to the linear replacement. An SDL entry of (0, blkA, blkE), shown in FIG. 4C, indicates that the assigned replacement block blkE has no defect and data to be written into the defective block blkA in the user area is written into the replacement block blkE in the spare area. An SDL entry of (1, blkA, blkE) shown in FIG. 4D, indicates that a defect occurs in the replacement block blkE of the spare area which replaced the defective block blkA of the user area. In such case, a new replacement block is assigned according to the direct pointer method. FIG. 5 is a partial diagram of an optical disc recording/playback (R/P) device relating to the recording operation. The optical disc (R/P) device includes an optical pickup to write data into and playback data from the optical disc; a servo unit controlling the optical pickup to maintain a certain distance between an object lens of the optical pickup and the optical disc, and to maintain a constant track; a data processor either processing and transferring the input data to the optical pickup, or receiving and processing the data reproduced through the optical pickup; an interface transmitting and receiving data to and from an external host; and a micro processor controlling the components. The interface of the optical disc R/P apparatus is coupled to a host such as a PC, and communicates commands and data with the host. If there is data to be recorded in an optical disc R/P apparatus, the host sends a recording command to the optical disc R/P apparatus. The recording command comprises a logical block address (LBA) designating a recording location and a transfer length indicating a size of the data. Subsequently, the host sends the data to be recorded to the optical disc R/P apparatus. Once the data to be written onto an optical disc is received, the optical disc R/P apparatus writes the data starting from the designated LBA. At this time, the optical disc R/P apparatus does not write the data into areas having by referring to the PDL and SDL which indicate defects of the optical disc. Referring back to FIG. 4A, the optical disc R/P apparatus skips physical sectors listed in the PDL and replaces the physical blocks listed in the SDL, within the area between A and B, with assigned replacement blocks in the spare area during the recording. If a defective block not listed in the SDL or a block prone to an error is found during the recording or playback, the optical disc R/P apparatus considers such blocks as defective blocks. As a result, optical disc R/P apparatus searches for a replacement block in the spare area to rewrite the data corresponding to the defective block and lists the first sector's number of the defective block and the first sector's number of the replacement block at the SDL entry. To perform the linear replacement, namely to write the data into the assigned replacement block in the spare area when finding a defective block (listed or not listed in the SDL), the optical disc R/P apparatus must move the optical pickup from the user area to the spare area and then back to the user area. Because moving the optical pickup may take time, a linear replacement interferes a real time recording. Thus, defect area management methods for real time recording, such as audio visual apparatus, have been extensively discussed. One method is to use a skipping algorithm where a defective block is skipped and data is written into the next normal block, similarly to the slipping replacement algorithm. If this algorithm is employed, the optical pickup does not need to be moved to the spare area whenever a defective block is found, such that the time needed for moving the optical pickup can be reduced and the interference with the real time recording can be removed. For example, if the PC-data which does not require real time processing, as shown in FIG. 4A, is received when the SDL is used, the linear replacement algorithm is executed upon finding defective blocks blkA and blkB. If the received data requires real time, as shown in the area between B and C of FIG. 4A, the skipping algorithm is used upon finding defective block blkC. Namely, the linear replacement is not performed. For linear replacement, the PSN of the defective block is maintained as is and the LSN of the defective block is moved to the replacement block. For the skipping algorithm, both the LSN and PSN of the defective block blkC are maintained as they are. Accordingly, when the host reads the data recorded according to the skipping algorithm, the microprocessor transmits all data including data of defective blocks through the interface. However, the host cannot identify the data of the skipped defective block since it does not have information regarding the skipped defective blocks, resulting in an incorrect playback of the data. Therefore, the microprocessor of the optical disc R/P apparatus must instruct the optical pickup not to read the data of defective blocks among the data playback from the optical disc and transmitted to the host. Here, the information regarding the defective blocks, as shown in FIGS. 4B˜4D, remains in the SDL and the microcomputer may transmit the information to the host, on request. The SDL is information on defective blocks with respect to the linear replacement algorithm. However, the microprocessor cannot discriminate information recorded with respect to linear replacement from information recorded with respect to skipping algorithm not performing the linear replacement. Consequently, if skipping algorithm has been used, the microprocessor may transmit incorrect information to the host. Likewise, the host cannot identify the data of skipped defective blocks, resulting in an erroneous playback of data. Moreover, because of the size of the spare may not be sufficient, the spare area may become full while the DMA has redundant areas for listing defective blocks at the PDL or SDL entries. If the spare area is full, a spare full flag in the DMA is set. The spare area may become full prior to the DMA when the initial allocation of spare area is insufficient or when the available spare area is quickly reduced due to defects, particularly burst defects occurring in the spare area. Because it is desirable to increase the recording capacity of the optical disc, a method of further reducing the size of the spare area has been considered. In such case, however, there is a higher possibility that the spare area will become full prior to the DMA. Consequently, if the optical disc R/P apparatus finds a defective block that is not listed in the SDL or is listed in the SDL but requires a new replacement block as shown in FIGS. 4B˜4D while recording or playing back data, it checks the spare full flag of the DMA. If the spare full flag is in a reset state which indicates that available spare areas remain, the apparatus records the data of the defective block in a replacement block in the spare area and lists a new SDL entry or modifies the existing SDL entry. On the other hand, if the spare full flag is in a set state, which indicates that the spare area is full, a linear replacement cannot be executed even if the DMA has redundant area. If the linear replacement cannot be executed when necessary, the management of defective area cannot be maintained. As a result, the disc cannot be used. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art. An object of the present invention is to provide an optical disc and a defect management method for managing defect of the optical disc according to whether a replacement block has been assigned. Another object of the present invention is to provide a data recording method and apparatus which discriminately store and manage information on defective blocks within the optical disc according whether a replacement block has been assigned. Still another object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for storing information on defective blocks according to whether linear replacement is performed. A further object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for storing information on defective blocks without application of linear replacement if there is no available replacement area. A still further object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for discriminately storing information on defective blocks skipped for real time processing or skipped due to a full spare area, and information on defective blocks related to linear replacement algorithm. A still further object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for discriminately storing information on defective blocks listed at SDL entries by giving identification information to the SDL entries according to whether linear replacement is performed. Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, an optical disc has a DMA for managing defects and comprises an area for recording identification information in the DMA. The identification information allows discrimination between when a replacement block has been assigned according to a linear replacement algorithm and when a replacement block is not assigned. The area for recording the identification information is assigned in a reserved area of a SDL entry in the DMA. The identification information indicates that a defective block was listed in the SDL either while data was recorded according to a skipping algorithm or when a spare area was full. A defect management method of an optical disc according to an embodiment of the present invention comprises determining whether to assign a replacement block if a defective block is found during recording in the optical disc; and storing information on the defective block and storing identification information to discriminate a defective block with an assigned replacement block from a block without an assigned replacement block, based upon the results of the determination. Information regarding a replacement block is not stored during real time recording. Also, information regarding a replacement block is not assigned when there is no available replacement area. The identification information is stored at a secondary defect list in a defect management area together with the defective block information. Moreover, the forced reassignment marking information is reset to 0. Furthermore, the defective block information discriminated based upon the identification information is notified to a host that transmits a recording command. In another embodiment, a defect management method of an optical disc according to the present invention comprises detecting existence/non-existence of an available replacement area if a defective block is found while recording the data in the optical disc; and storing information on the defective block and identification information indicating that a replacement block is assigned if available replacement area exists or a replacement block is not assigned if available replacement area does not exist. Available replacement block is determined not to exist if the data is recorded by skipping the defective block. Also, available replacement block is determined not to exist if the spare area is full. In still another embodiment, a data recording method of an optical disc comprises receiving data and information of areas where data will be written in the optical disc; reading defective area information of the optical disc; detecting whether the defective area information covers a defective block that is found during the recording; detecting whether a replacement block is assigned to the defective block based upon the identification information contained in the defective area information if the found defective block is covered by the defective area information, and if a replacement block is assigned, writing the data in the assigned replacement block and, if not, finding a new available replacement block to write the data therein; and determining whether the defective block will be replaced with a replacement block if the defective block is not covered by the defective area information, and storing information on the defective block and the identification information to discriminate if a replacement block is assigned to the defective block in the defect management area of the disc based upon a result of the determination. The identification information is represented with at least one bit of a reserved area at a secondary defect list within the defect management area. Moreover, a real time data recording method of an optical disc according to the present invention comprises receiving data and information regarding the area where the data will be written in the optical disc; skipping a defective block and writing the data in a following normal block if the defective block is found during the real time recording; and storing information regarding the skipped defective block discriminately from information on a defective block replaced with a replacement block. The identification information is set to indicate that the defective block is not replaced with a replacement block. If the defective block is found while recording the data by skipping defective blocks and if information regarding a replacement block for the defective block is listed at a secondary defect list entry, the replacement block information is maintained as is when the defective block information is stored. Furthermore, an optical disc recording apparatus comprises a controller detecting a defective block and determining whether a replacement block is assigned to the defective block while recording the data; an optical pickup recording and playing back data in/from the optical disc according to control of the controller; and a storage unit storing information regarding the defective block and identification information to discriminate whether a replacement block is assigned to a defective block. The storage unit does not store the replacement block during real time recording and represents this fact using the identification information. The storage unit also does not store the replacement block if there is no available replacement area and represents this fact using the identification information. These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein: FIG. 1 shows a data area of a conventional optical disc; FIG. 2 illustrates a structure of a conventional SDL entry; FIG. 3A illustrates a conventional slipping replacement algorithm; FIG. 3B illustrates a conventional linear replacement algorithm; FIG. 4A illustrates a state of recording data according to the linear replacement algorithm or skipping algorithm when using SDL in the conventional optical disc; FIGS. 4B to 4D illustrate embodiments of SDL entries listing information regarding defective blocks occurring when recording or playing back data according to the linear replacement algorithm; FIG. 5 is a block diagram of a conventional optical disc recording/playback apparatus; FIG. 6 is a block diagram of an optical disc recording/playback apparatus according to an embodiment of the present invention; FIG. 7A illustrates assigning identification information to an SDL entry according to an optical disc defect managing method of the present invention; FIGS. 7B to 7D illustrate SDL entries discriminately listed while recording or playing back data according to the skipping algorithm and linear replacement algorithm using the identification information; FIGS. 8A and 8B are flow charts showing how defective area is managed using the identification information of FIG. 7 according to an embodiment of the present invention; and FIG. 9 illustrates an SDL entry listed while recording or playing back data according to the skipping algorithm after changing a definition of FRM in the optical disc defect managing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The present invention distinguishably lists information regarding defective blocks in the SDL according to whether linear replacement has been executed upon finding defective blocks while recording or playing back data in or from an optical disc. In one embodiment, the present invention distinguishably lists such information by assigning an identification information. In another embodiment, such information is distinguishably listed by changing a part of the FRM definition. In the first embodiment of the present invention, information indicating whether or not a corresponding defective block is listed while data is recorded according to the linear replacement algorithm is written in a reserved area in the SDL entry. FIG. 6 shows an optical disc recording/playback apparatus according to an embodiment of the present invention comprising an optical pickup 602 recording and playing back data to and from an optical disc 601; a servo unit 603 controlling the optical pickup 602 to maintain a certain distance from an object lens of the optical pickup 602 to the optical disc 601, and to maintain a specified track; a data processor 604 processing the input data and transmitting the processed data to the optical pickup 602; a DMA information storage unit 606 reading and storing DMA information written in a DMA area of the optical disc via the data processor 604; an interface 605 transmitting and receiving data to and from an external host 608; and a controller 607 detecting whether a defective block exists during recording/playback of data and determining whether a linear replacement has been executed to the defective block. The interface 605 of the optical disc R/P apparatus is coupled to the host 608, such as a PC, and communicates commands and data with the host 608. When a rewritable optical disc, for example a DVD-RAM, is inserted into the apparatus of the present invention, the SDL and PDL entries listed in the DMA area of the optical disc 601 are stored in the DMA information storage unit 606 through the data processor 604 under the control of the controller 607. At this time, the identification information indicating whether linear replacement has been performed with respect to a corresponding defective block is added into the DMA information stored in the DMA information storage unit 606. For example, at least one bit of the reserved area in the existing SDL entry is assigned as the identification information (ID Info) bit. The ID Info bit is set to either a value of 1 or 0 to distinguish whether the linear replacement has been executed to the information listed in the SDL. Namely, the linear replacement algorithm is not performed when skipping algorithm is performed or when the spare area is full. In the present invention, the ID Info bit is called a linear replacement control (LRC) bit and shown in, e.g., FIG. 7A. Referring to FIG. 7A, each SDL entry comprises an LRC area, an area for storing a sector number of the first sector of a block having defective sectors, and an area for storing a sector number of the first sector of a replacement block replacing the defective block. Because the LRC bit has a different meaning from the FRM bit, the FRM may also be included in the SDL. However, in this embodiment of the present invention, the FRM bit is not used. As shown in FIG. 7B, a LRC bit value of 0 in the SDL entry means that the SDL entry was made while recording the data according to the linear replacement algorithm. As shown in FIG. 7C or 7D, a LRC bit value of 1 means that the SDL entry was made while recording the data according to the skipping algorithm rather than the linear replacement or while the spare area is full. When a defective block is found during recording of data according to the linear replacement algorithm, the data corresponding to the defective block is recorded in a replacement block and the LRC bit is reset to 0, provided that the spare area is not full. Otherwise, if the spare area is full, the linear replacement is not performed and the LRC bit is set to 1. Also, when a defective block is found while recording the data according to the skipping algorithm, the defective block is skipped and the LRC bit of an SDL entry corresponding to the defective block is set to 1. Once a predetermined time has passed, for example, during the recording of data or after completing the recording, the controller 607 transmits information regarding the defective blocks to the host. At such time, the controller 607 can detect whether or not the corresponding SDL entry was made while recording the data according to the linear replacement algorithm based upon the LRC bit, thereby being able to transmit the correct information to the host. Accordingly, the host can appropriately command not to record/playback data in/from defective blocks listed in the SDL. The host may issue a write/read command in view of the defective blocks listed in the SDL. Namely, the host would command not to record or playback data in or from defective blocks listed in the SDL. The optical disc R/P apparatus receives both the data and information of areas where data will be written in the optical disc, and reads the information regarding defective areas of the optical disc. The optical disc R/P apparatus detects whether the defective area information covers a defective block that is found during the recording; and detects whether a replacement block is assigned to the defective block based upon the identification information contained in the defective area information if the found defective block is covered by the defective area information. If a replacement block is assigned, writing the data in the assigned replacement block is performed and, if not, finding a new available replacement block to write the data therein is performed. The optical disc R/P apparatus further determines whether the defective block will be replaced with a replacement block if the defective block is not covered by the defective area information, and stores information on the defective block and the identification information to discriminate if a replacement block is assigned to the defective block in the defect management area of the disc based upon a result of the determination. The identification information is represented with at least one bit of a reserved area at a secondary defect list within the defect management area. Thus, the optical disc R/P apparatus bypasses the defective blocks listed in the SDL while writing/reading the data. In such case, the LRC bit of SDL entry is set to 1 upon encountering a new defective block and location information of the defective block is entered. Since information regarding the replacement block is not necessary, the existing value is kept as is or a value of 0 is entered Alternatively, if the host issues a write/read command regardless of the defective block information in the SDL, the controller 607 of the optical disc R/P apparatus identifies the defective blocks listed in the SDL based upon the DMA information stored in the DMA information storage unit 606 during the data record/playback. If the read command is issued, whether a replacement block should be found can be determined based upon the LRC bit of the SDL entry where the defective block is listed. If the write command is issued, the LRC bit of an existing entry may change depending upon whether or not the linear replacement algorithm is performed. Here, a newly found defective block is processed in the same way as described above. For example, if a defective block listed in the SDL is found while recording data according to the skipping algorithm, the defective block is skipped and the LRC bit of the SDL entry corresponding to the defective block is set to 1. At this time, if the information regarding a replacement block is written in the area for storing the sector number of the first sector of the replacement block in the SDL entry, the information is maintained as is. For example, a SDL entry of (0, blkC, blkG) as shown in FIG. 7B, means that data was recorded according to the linear replacement algorithm and a replacement block has been assigned. If such a SDL entry is met while recording data according to the skipping algorithm, the defective block blkC is skipped and the SDL entry is modified into (1, blkC, blkG) as shown in FIG. 7C. Thus, the SDL entry of (1, blkC, blkG) as show in FIG. 7C, means that data was recorded according to the skipping algorithm, a defect occurred in block blkC, and the information regarding the replacement block blkG is maintained but not used during the record/playback. A SDL entry of (1, blkC, 0) as shown in FIG. 7D, means that data was recorded according to the skipping algorithm and a new defective block blkC was found and entered. If such SDL entry is found while recording the data according to the skipping algorithm, the defective block blkC is skipped and the SDL entry is maintained as is. If the information regarding the replacement block of the spare area, which was previously listed in the SDL entry according to the linear replacement algorithm, is maintained in the SDL entry as it was while recording the data according to the skipping algorithm, the replacement block information can be used in subsequent recordings. In other words, when writing data into such defective block listed in the SDL according to the linear replacement algorithm, if the replacement block information does not exist, a replacement block for the defective block must be newly assigned to the spare area. However, if the information regarding the replacement block is maintained, the location of the replacement block previously assigned can be used as the newly assigned replacement block. For example, a block following the replacement block blkH, shown in FIG. 4A, is assigned as the new replacement block. Since a replacement block that was previously assigned cannot be re-used, the available capacity of the optical disc is reduced, thereby decreasing the efficiency of the optical disc. Therefore, if the replacement block information is maintained even while recording data according to the skipping algorithm, as described above, the replacement block previously assigned can be re-used as is when writing data according to the linear algorithm in a subsequent recording, thereby increasing the efficiency of the optical disc. Specifically, if the information regarding the replacement block blkG, where data of the defective block blkC was written during the linear replacement recording, is kept in the SDL entry during the real time recording, the data of the defective block blkC is written not into a new replacement block in the spare area but into the replacement block blkG, which has already been assigned, during the next linear replacement recording. Meanwhile, if a defective block requiring a new replacement block is found during the record/playback using the linear replacement, but there is no replacement block for the defective block, namely the spare area is full (provided the DMA has redundancy), the LRC bit value of the SDL entry is set to 1. At this time, a replacement block does not exist. As a result, the replacement block information is not listed and the location information of the defective block is listed as shown in FIG. 7D. If the spare full flag and the LRC bit is set to 1 during the playback or recording, data of the defective block cannot be read and data cannot be written in the defective block because the replacement block for the defective block does not exist and the linear replacement cannot be executed. FIGS. 8A and 8B are flow charts showing the above operations of the optical disc R/P apparatus according to an embodiment of the present invention. If there is data to be recorded, the host inputs a write command and if there is playback of data, the host inputs a read command, via the interface of the optical disc R/P apparatus (800). Once a write or read command is received from the host, the controller 607 of the optical disc R/P apparatus determines whether the input data requires a real time recording/playback (802). When the data is determined to require real time recording, the apparatus starts to write the data on a location of the LBA designated by the host (804). A determination is made whether the writing of data is completed (806) and if a defective block is found when the writing of data is not completed (808), the defective block is skipped and the data is written in a next normal block (810). Information regarding the skipped defective block is entered in the SDL (812) and sent to the host (814). This information is entered in a way distinguishable from an information of a defective block found while performing the linear replacement algorithm. Thus, the controller 607 can distinguish SDL entry made while recording data according to the skipping algorithm from a SDL entry made while recording data according to the linear replacement algorithm. For this purpose, the LRC bit of the SDL is set to 1 and the location information of the defective block is entered in the SDL entry. The defective block found in step 808 may be a newly encountered defective block or a block already listed in the SDL. If the defective block is not listed in the SDL, the defective block is new and the location information regarding the defective block is listed in the SDL entry by setting the LRC bit to 1, such as (1, blkC, 0) shown in FIG. 7D. If the defective block is listed in the SDL, the SDL is corrected by setting the LRC bit to 1 and maintaining the information regarding the replacement block, such as (1, blkC, blkG) shown in FIG. 7C. Such procedure is performed until the recording of data by the write command of the host is completed. If the writing is completed (806), the controller 607 transmits a command execution report to the host (816). When the data is determined to require real time playback, the apparatus starts to read the data from a location of the LBA designated by the host (804). As in the recording, a determination is made whether reading of data is completed (806). However, if a defective block is found when the reading of data is not completed (808), the defective block may skipped, a partially correct data may be read from the defective block or zero padding data may be returned (not shown in FIG. 8A). Information regarding the skipped defective block is entered in the SDL (812) and sent to the host (814). Such procedure is performed until the playback of data by the read command of the host is completed. If the reading is completed (806), the controller 607 transmits a command execution report to the host (816). During recording/playback, the controller 607 may send the information regarding the defective block to the host in various ways. For example, the defective block information can be embedded in a header for transmission to the host, or a new command allowing recognition of the skipped block can be generated and transmitted to the host, or the defective block information may be transmitted together with the command execution report to the host after completing the recording/playback of the real time data. If it is determined that the data to be recorded does not require real time recording in step 802, namely the data is PC-data, the controller 607 writes/reads the data starting on/from the LBA designated by the host (820). If a read command is received, the playback is carried out starting from the LBA designated by the host and if a write command is received, the recording is carried out starting from the LBA designated by the host. When writing/reading of data is not completed (822) and if a defective block is found (824), a determination is made whether the defective block is listed in the SDL (826). If the defective block is not listed in the SDL, a replacement block from the spare area is assigned. Thus, the spare full flag is checked to determine whether there are any available replacement blocks, i.e. whether the spare area is full (828). A spare full flag of 1 indicates that there are no available replacement blocks. If there are no available replacement blocks, the LRC information in the SDL is set to 1, the location information of the defective block is listed and the location information of the replacement block is set to 0, such as (1, blkC, 0) shown in FIG. 7D (830). The information on defective block is transmitted to the host (832) and a report of an error in the recording/playback process is sent to the host (834). If the spare area is not full during writing of data, a replacement block is assigned and the data to be written in the defective block is written in the replacement block (836). Also, the location information of the defective block and the replacement block is listed in the SDL and the LRC information in the SDL is set to 0, such as (0, blkC, blkG) shown in FIG. 7B (836). The information on defective block is transmitted to the host (838) and the process returns to step 820 to record more data (840). During reading of data, even if there are available replacement blocks, data cannot be read from the defective block. Accordingly, a report of an error in the playback is sent to the host (840). However, the information on the defective block may be transmitted to the host for future use (838) and a replacement block may even be assigned for use in the next recording (not shown). If a replacement block is assigned, the location information of the defective block and the replacement block is listed in the SDL and the LRC information in the SDL is set to 0 in step 836. If the defective block is listed in the SDL, a further determination is made whether a replacement block has been assigned (842). Namely, if the LRC bit is 0, the SDL entry was made previously while recording/playback of data according to the linear replacement algorithm. Thus, the recording/playback is continued according to the linear replacement algorithm (844) and the process returns to step 820 for more recording/playback of data. In other words, if a replacement block is assigned to the SDL entry, the optical pickup is moved to the replacement block and the data is written/read in/from the replacement block. If the LRC bit of the SDL entry is 1 and a replacement block is listed, such as (1, blkC, blkG) shown in FIG. 7C, the listed replacement block is used to perform the linear replacement and the LRC bit is corrected to 0, making the SDL entry to (0, blkC, blkG) shown in FIG. 7B. If the assigned replacement block is defective, a new replacement block may be assigned according to the direct pointer method and the data is then written/read in/from the assigned replacement block. However, if the spare area becomes full prior to the DMA and there is no replacement block to be assigned, the location information of the defective block of the SDL entry is maintained and the LRC bit is changed into 1, such as (1, blkC, 0) shown in FIG. 7D, indicating not to execute the linear replacement. If a replacement block has not been assigned in the SDL entry, the spare full flag is checked to determine whether there are any available replacement blocks (846). Namely, if the LRC bit of the SDL entry is set to 1, the SDL entry may have been made while data was written/read according to the skipping algorithm or while the spare area was full. Accordingly, if there are no available replacement blocks, i.e. the spare area is full, a report of a write/read error in the recording/playback process is sent to the host (834). However, when formatting an optical disc whose spare area is full, the SDL may be moved to the PDL depending upon the formatting method, such that the spare area may no longer be full. In any case, if the spare area is not full, the process is the same as when the spare area is not full for defective blocks not listed in the SDL (836-840). The above procedure for non real time data is carried out until the recording/playback of data by the writing/reading command of the host is completed. If the writing/reading is completed, the controller 607 sends a command execution report to the host (848). Here, the controller 607 sends the information regarding the skipped defective block to the host in the various methods as described above with reference to FIG. 8A, step 816. In a second embodiment of the present invention, the definition of the FRM is changed to distinguish a linear replacement from a skipping replacement. If a defective block blkC is found while recording data according to the skipping algorithm in real time, the SDL entry is listed as (0, blkC, 0) shown in FIG. 9. At this time, a replacement block is not needed, so the information regarding the replacement block in the spare area is not changed or is listed as 0. Only the definition of the FRM changes. For example, if FRM and the replacement block are both 0, it is modified to be recognized as indicating a defective block found while performing the skipping algorithm or as indicating an assigned replacement block rather than a defective case of performing the linear replacement. This is because the defective block, even if found during the real time recording, is skipped and a replacement block for the defective block does not exist in the spare area. In addition, this aims at distinguishing the SDL entry listed according to the skipping algorithm from the SDL entry listed according to the linear replacement algorithm. Even under the condition that the area between B and C in FIG. 4A was listed according to the linear replacement algorithm and the defective block information such as (0, blkC, blkG) was kept as the SDL entry, if the area is used for rewriting according to the skipping algorithm, the SDL entry is modified into (0, blkC, 0). In sum, the present invention has the following advantages. Primarily, since the controller can detect existence/non-existence of the linear replacement based upon the LRC bit assigned to each SDL entry, the optical disc R/P apparatus (namely, a drive) can transmit the correct information to the host. Accordingly, even if incorrect data of skipped blocks, namely previous data written in the skipped blocks is reproduced by the optical disc R/P apparatus and transmitted to the host during the reproduction of data, the host discards the data of the skipped blocks and reads only the data of normal blocks based upon the defective block information received from the controller. In other words, the present invention can prevent an error occurring when the host does not know the information regarding the skipped blocks. If a replacement block has not been assigned in the SDL entry, the spare full flag is checked to determine whether there are any available replacement blocks (846). Namely, if the LRC bit of the SDL entry is set to 1, the SDL entry may have been made while data was written/read according to the skipping algorithm or while the spare area was full. Accordingly, if there are no available replacement blocks, i.e. the spare area is full, a report of a write/read error in the recording/playback process is sent to the host (834). However, when formatting an optical disc whose spare area is full, the SDL may be moved to the PDL depending upon the formatting method, such that the spare area may no longer be full. In any case, if the spare area is not full, the process is the same as when the spare area is not full for defective blocks not listed in the SDL (836-840). The foregoing embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to an optical recording medium which allows rewriting, and more particularly to a method and apparatus of recording data in the optical recording medium, wherein defect areas can be managed. 2. Description of Related Art An optical storage medium is generally divided into a read only memory (ROM), a write once read many (WORM) memory into which data can be written one time, and rewritable memories into which data can be written several times. Rewritable optical storage mediums, i.e. optical discs, include rewritable compact discs (CD-RW) and rewritable digital versatile discs (DVD−RW, DVD-RAM, DVD+RW). The operations of writing and playing back data in a rewritable optical disc may be repeated. This repeated process alters the ratio of storage layers for recording data into the optical disc from the initial ratio. Thus, the optical discs lose its characteristics and generate an error during recording/playback. This degradation is indicated as a defective area at the time of formatting, recording on or playing back from an optical storage medium. Also, defective areas of a rewritable optical disc may be caused by a scratch on its surface, particles of dirt and dust, or errors during manufacture. Therefore, in order to prevent writing into or reading out of the defective area, management of such defective areas is necessary. FIG. 1 shows a defect management area (DMA) in a lead-in area and a lead-out area of the optical disc to manage a defect area. Particularly, the data area is divided into a plurality of zones for the defect area management, where each zone is further divided into a user area and a spare area. The user area is where data actually written and the spare area is used when a defect occurs in the user area. There are four DMAs in one disc, e.g. DVD-RAM, two of which exist in the lead-in area and two exist in the lead-out area. Because managing defective areas is important, the same contents are repeatedly recorded in all four DMAs to protect the data. Each DMA comprises two blocks of 32 sectors, where one block comprises 16 sectors. The first block of the DMA, called a DDS/PDL block, includes a disc definition structure (DDS) and a primary defect list (PDL). The second block of the DMA, called an SDL block, includes a secondary defect list (SDL). The PDL corresponds to a primary defect data storage and the SDL corresponds to a secondary defect data storage. The PDL generally stores entries of defective sectors caused during the manufacture of the disc or identified when formatting a disc, namely initializing and re-initializing a disc. Each entry is composed of an entry type and a sector number corresponding to a defective sector. The SDL lists defective areas in block units, thereby storing entries of defective blocks occurring after formatting or defective blocks which could not be stored in the PDL during the formatting. As shown in FIG. 2 , each SDL entry has an area for storing a sector number of the first sector of a block having defective sectors, an area for storing a sector number of the first sector of a block replacing the defective block, and reserved areas. Also, each SDL entry is assigned a value of 1 bit for forced reassignment marking (FRM). A FRM bit value of 0 indicates that a replacement block is assigned and that the assigned block does not have a defect. A FRM bit value of 1 indicates that a replacement block has not been assigned or that the assigned replacement block has a defect. Thus, to record data in a defective block listed as a SDL entry, a new replacement block must be found to record the data. Accordingly, defective areas, i.e. defective sectors or defective blocks, within the data area are replaced with normal or non-defective sectors or blocks by a slipping replacement algorithm and a linear replacement algorithm. The slipping replacement is utilized when a defective area or sector is recorded in the PDL. As shown in FIG. 3A , if defective sectors m and n, corresponding to sectors in the user area, are recorded in the PDL, such defective sectors are skipped to the next available sector. By replacing the defective sectors by subsequent sectors, data is written to a normal sector. As a result, the user area into which data is written slips and occupies the spare area in the amount equivalent to the skipped defective sectors. The linear replacement is utilized when a defective block is recorded in the SDL or when a defective block is found during playback. As shown in FIG. 3B , if defective blocks m and n, corresponding to blocks in either the user or spare area, are recorded on the SDL, such defective blocks are replaced by normal blocks in the spare area and the data to be recorded in the defective block are recorded in an assigned spare area. To achieve the replacement, a physical sector number (PSN) assigned to a defective block remains, while a logical sector number (LSN) is moved to the replacement block along with the data to be recorded. Linear replacement is effective for non real-time processing of data. For convenience, a data which does not require real time processing is hereinafter called a personal computer (PC)-data. If a replacement block listed in the SDL is found to be defective, a direct pointer method is applied to the SDL listing. According to the direct pointer method, the defective replacement block is replaced with a new replacement block and the SDL entry of the defective replacement block is modified into a sector number of the first sector of the new replacement block. FIG. 4A shows a procedure to manage a defective block found while writing or reading data into or from the user area. FIGS. 4 B˜ 4 D show embodiments of SDL entries generated according to the linear replacement algorithm. Each SDL entry has, in order, a FRM, a sector number of the first sector of the defective block, and a sector number of the first sector of the replacement block. For example, if the SDL entry is (1, blkA, 0) as shown in FIG. 4B , a defective block has been newly found during the reproduction and is listed in the SDL. This entry indicates that a defect occurs in block blkA and that there is no replacement block. The SDL entry is used to prevent data from being written into the defective block in the next recording. Thus, during the next recording, the defective block blkA is assigned a replacement block according to the linear replacement. An SDL entry of (0, blkA, blkE), shown in FIG. 4C , indicates that the assigned replacement block blkE has no defect and data to be written into the defective block blkA in the user area is written into the replacement block blkE in the spare area. An SDL entry of (1, blkA, blkE) shown in FIG. 4D , indicates that a defect occurs in the replacement block blkE of the spare area which replaced the defective block blkA of the user area. In such case, a new replacement block is assigned according to the direct pointer method. FIG. 5 is a partial diagram of an optical disc recording/playback (R/P) device relating to the recording operation. The optical disc (R/P) device includes an optical pickup to write data into and playback data from the optical disc; a servo unit controlling the optical pickup to maintain a certain distance between an object lens of the optical pickup and the optical disc, and to maintain a constant track; a data processor either processing and transferring the input data to the optical pickup, or receiving and processing the data reproduced through the optical pickup; an interface transmitting and receiving data to and from an external host; and a micro processor controlling the components. The interface of the optical disc R/P apparatus is coupled to a host such as a PC, and communicates commands and data with the host. If there is data to be recorded in an optical disc R/P apparatus, the host sends a recording command to the optical disc R/P apparatus. The recording command comprises a logical block address (LBA) designating a recording location and a transfer length indicating a size of the data. Subsequently, the host sends the data to be recorded to the optical disc R/P apparatus. Once the data to be written onto an optical disc is received, the optical disc R/P apparatus writes the data starting from the designated LBA. At this time, the optical disc R/P apparatus does not write the data into areas having by referring to the PDL and SDL which indicate defects of the optical disc. Referring back to FIG. 4A , the optical disc R/P apparatus skips physical sectors listed in the PDL and replaces the physical blocks listed in the SDL, within the area between A and B, with assigned replacement blocks in the spare area during the recording. If a defective block not listed in the SDL or a block prone to an error is found during the recording or playback, the optical disc R/P apparatus considers such blocks as defective blocks. As a result, optical disc R/P apparatus searches for a replacement block in the spare area to rewrite the data corresponding to the defective block and lists the first sector's number of the defective block and the first sector's number of the replacement block at the SDL entry. To perform the linear replacement, namely to write the data into the assigned replacement block in the spare area when finding a defective block (listed or not listed in the SDL), the optical disc R/P apparatus must move the optical pickup from the user area to the spare area and then back to the user area. Because moving the optical pickup may take time, a linear replacement interferes a real time recording. Thus, defect area management methods for real time recording, such as audio visual apparatus, have been extensively discussed. One method is to use a skipping algorithm where a defective block is skipped and data is written into the next normal block, similarly to the slipping replacement algorithm. If this algorithm is employed, the optical pickup does not need to be moved to the spare area whenever a defective block is found, such that the time needed for moving the optical pickup can be reduced and the interference with the real time recording can be removed. For example, if the PC-data which does not require real time processing, as shown in FIG. 4A , is received when the SDL is used, the linear replacement algorithm is executed upon finding defective blocks blkA and blkB. If the received data requires real time, as shown in the area between B and C of FIG. 4A , the skipping algorithm is used upon finding defective block blkC. Namely, the linear replacement is not performed. For linear replacement, the PSN of the defective block is maintained as is and the LSN of the defective block is moved to the replacement block. For the skipping algorithm, both the LSN and PSN of the defective block blkC are maintained as they are. Accordingly, when the host reads the data recorded according to the skipping algorithm, the microprocessor transmits all data including data of defective blocks through the interface. However, the host cannot identify the data of the skipped defective block since it does not have information regarding the skipped defective blocks, resulting in an incorrect playback of the data. Therefore, the microprocessor of the optical disc R/P apparatus must instruct the optical pickup not to read the data of defective blocks among the data playback from the optical disc and transmitted to the host. Here, the information regarding the defective blocks, as shown in FIGS. 4 B˜ 4 D, remains in the SDL and the microcomputer may transmit the information to the host, on request. The SDL is information on defective blocks with respect to the linear replacement algorithm. However, the microprocessor cannot discriminate information recorded with respect to linear replacement from information recorded with respect to skipping algorithm not performing the linear replacement. Consequently, if skipping algorithm has been used, the microprocessor may transmit incorrect information to the host. Likewise, the host cannot identify the data of skipped defective blocks, resulting in an erroneous playback of data. Moreover, because of the size of the spare may not be sufficient, the spare area may become full while the DMA has redundant areas for listing defective blocks at the PDL or SDL entries. If the spare area is full, a spare full flag in the DMA is set. The spare area may become full prior to the DMA when the initial allocation of spare area is insufficient or when the available spare area is quickly reduced due to defects, particularly burst defects occurring in the spare area. Because it is desirable to increase the recording capacity of the optical disc, a method of further reducing the size of the spare area has been considered. In such case, however, there is a higher possibility that the spare area will become full prior to the DMA. Consequently, if the optical disc R/P apparatus finds a defective block that is not listed in the SDL or is listed in the SDL but requires a new replacement block as shown in FIGS. 4 B˜ 4 D while recording or playing back data, it checks the spare full flag of the DMA. If the spare full flag is in a reset state which indicates that available spare areas remain, the apparatus records the data of the defective block in a replacement block in the spare area and lists a new SDL entry or modifies the existing SDL entry. On the other hand, if the spare full flag is in a set state, which indicates that the spare area is full, a linear replacement cannot be executed even if the DMA has redundant area. If the linear replacement cannot be executed when necessary, the management of defective area cannot be maintained. As a result, the disc cannot be used.
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<SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art. An object of the present invention is to provide an optical disc and a defect management method for managing defect of the optical disc according to whether a replacement block has been assigned. Another object of the present invention is to provide a data recording method and apparatus which discriminately store and manage information on defective blocks within the optical disc according whether a replacement block has been assigned. Still another object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for storing information on defective blocks according to whether linear replacement is performed. A further object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for storing information on defective blocks without application of linear replacement if there is no available replacement area. A still further object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for discriminately storing information on defective blocks skipped for real time processing or skipped due to a full spare area, and information on defective blocks related to linear replacement algorithm. A still further object of the present invention is to provide an optical disc, a defect management method for managing defect of such optical disc, and data recording method and apparatus for discriminately storing information on defective blocks listed at SDL entries by giving identification information to the SDL entries according to whether linear replacement is performed. Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, an optical disc has a DMA for managing defects and comprises an area for recording identification information in the DMA. The identification information allows discrimination between when a replacement block has been assigned according to a linear replacement algorithm and when a replacement block is not assigned. The area for recording the identification information is assigned in a reserved area of a SDL entry in the DMA. The identification information indicates that a defective block was listed in the SDL either while data was recorded according to a skipping algorithm or when a spare area was full. A defect management method of an optical disc according to an embodiment of the present invention comprises determining whether to assign a replacement block if a defective block is found during recording in the optical disc; and storing information on the defective block and storing identification information to discriminate a defective block with an assigned replacement block from a block without an assigned replacement block, based upon the results of the determination. Information regarding a replacement block is not stored during real time recording. Also, information regarding a replacement block is not assigned when there is no available replacement area. The identification information is stored at a secondary defect list in a defect management area together with the defective block information. Moreover, the forced reassignment marking information is reset to 0 . Furthermore, the defective block information discriminated based upon the identification information is notified to a host that transmits a recording command. In another embodiment, a defect management method of an optical disc according to the present invention comprises detecting existence/non-existence of an available replacement area if a defective block is found while recording the data in the optical disc; and storing information on the defective block and identification information indicating that a replacement block is assigned if available replacement area exists or a replacement block is not assigned if available replacement area does not exist. Available replacement block is determined not to exist if the data is recorded by skipping the defective block. Also, available replacement block is determined not to exist if the spare area is full. In still another embodiment, a data recording method of an optical disc comprises receiving data and information of areas where data will be written in the optical disc; reading defective area information of the optical disc; detecting whether the defective area information covers a defective block that is found during the recording; detecting whether a replacement block is assigned to the defective block based upon the identification information contained in the defective area information if the found defective block is covered by the defective area information, and if a replacement block is assigned, writing the data in the assigned replacement block and, if not, finding a new available replacement block to write the data therein; and determining whether the defective block will be replaced with a replacement block if the defective block is not covered by the defective area information, and storing information on the defective block and the identification information to discriminate if a replacement block is assigned to the defective block in the defect management area of the disc based upon a result of the determination. The identification information is represented with at least one bit of a reserved area at a secondary defect list within the defect management area. Moreover, a real time data recording method of an optical disc according to the present invention comprises receiving data and information regarding the area where the data will be written in the optical disc; skipping a defective block and writing the data in a following normal block if the defective block is found during the real time recording; and storing information regarding the skipped defective block discriminately from information on a defective block replaced with a replacement block. The identification information is set to indicate that the defective block is not replaced with a replacement block. If the defective block is found while recording the data by skipping defective blocks and if information regarding a replacement block for the defective block is listed at a secondary defect list entry, the replacement block information is maintained as is when the defective block information is stored. Furthermore, an optical disc recording apparatus comprises a controller detecting a defective block and determining whether a replacement block is assigned to the defective block while recording the data; an optical pickup recording and playing back data in/from the optical disc according to control of the controller; and a storage unit storing information regarding the defective block and identification information to discriminate whether a replacement block is assigned to a defective block. The storage unit does not store the replacement block during real time recording and represents this fact using the identification information. The storage unit also does not store the replacement block if there is no available replacement area and represents this fact using the identification information. These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
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20040629
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20080527
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20050127
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59198.0
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TRUONG, LOAN
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METHOD AND APPARATUS OF RECORDING DATA IN THE OPTICAL RECORDING MEDIUM
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
| 2,004
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10,878,311
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ACCEPTED
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Liquid crystal display device and method of fabricating the same
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A method of fabricating a liquid crystal display device includes forming an active pattern and a data line on a substrate, forming a first insulating layer on the data line, forming a second insulating layer on the substrate, forming a gate electrode on the second insulating layer above the active pattern, forming a third insulating layer on the substrate, forming first and second contact holes through the second and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively, and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the first exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole.
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1. A method of fabricating a liquid crystal display device, comprising: forming an active pattern and a data line on a substrate; forming a first insulating layer on the data line; forming a second insulating layer on the substrate; forming a gate electrode on the second insulating layer above the active pattern; forming a third insulating layer on the substrate; forming first and second contact holes through the second and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively; and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the first exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole. 2. The method according to claim 1, wherein the forming an active pattern and a data line comprises: forming a silicon layer on the substrate; forming a first conductive metal layer on the silicon layer; patterning the first conductive metal layer and the silicon layer to form the active pattern and the data line; sequentially forming the first insulating layer and a second conductive metal layer on the substrate; patterning the second conductive metal layer and the first insulating layer using a mask having a pattern similar to a pattern of the data line and having a width larger than a width of the data line pattern; and simultaneously removing the patterned first conductive metal pattern and the second conductive metal pattern. 3. The method according to claim 2, wherein the silicon layer includes a crystallized silicon thin film. 4. The method according to claim 2, wherein the first conductive metal layer and the second conductive metal layer are formed of the same material and with the same thickness. 5. The method according to claim 1, further comprising the step of injecting impurity ions into predetermined regions of the active pattern using the gate electrode as a mask to form a source region and a drain region within the active pattern. 6. The method according to claim 5, wherein the impurity ions include Group V impurities. 7. The method according to claim 5, wherein the impurity ions include Group III impurities. 8. The method according to claim 1, wherein the source electrode and the drain electrode include transparent conductive material. 9. The method according to claim 1, wherein a portion of the drain electrode extends towards a pixel region to form a pixel electrode. 10. The method according to claim 1, wherein the first insulating layer directly contacts the data line and the second insulating layer directly contacts the active pattern. 11. A liquid crystal display device, comprising: an active pattern and a data line formed on a substrate; a first insulating layer on the data line; a second insulating layer on the substrate; a gate electrode formed on the second insulating layer above the active pattern; a third insulating layer formed on the substrate; first and second contact holes extending through the second and third insulating layers to expose first and second portions of the active pattern, respectively; a third contact hole extending through the first, second, and third insulating layers to expose a portion of the data line; a source electrode formed on the third insulating layer, the source electrode having a first portion within the first contact hole to contact the exposed first portion of the active pattern and a second portion within the third contact hole to contact the exposed portion of the data line; and a drain electrode formed on the third insulating layer, the drain electrode having a first portion within the second contact hole to contact the exposed second portion of the active pattern and a second portion extending into a pixel region of the liquid crystal display device. 12. The device according to claim 11, wherein the active pattern includes a first portion of silicon layer, and the data line is a double layer structure including a second portion of the silicon layer and a conductive metal material on the second portion of the silicon layer. 13. The device according to claim 11, wherein the source electrode and the drain electrode include transparent conductive material. 14. The device according to claim 13, wherein the transparent conductive material includes one indium-tin-oxide and indium-zinc-oxide. 15. The device according to claim 11, wherein the portion of the drain that extends into the pixel region is a pixel electrode. 16. The device according to claim 11, wherein the first insulating layer directly contacts the data line and the second insulating layer directly contacts the active pattern. 17. A method of fabricating a liquid crystal display device, comprising: forming an active pattern and a data line on a substrate; forming a first insulating layer on the substrate; forming a second insulating layer overlying the first insulating layer above the data line; forming a gate electrode on the first insulating layer above the active pattern; forming a third insulating layer on the substrate; forming first and second contact holes through the first and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively; and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole. 18. The method according to claim 17, wherein the step of forming the active pattern and the data line comprises: forming a silicon layer on the substrate; forming a first conductive metal layer on the silicon layer; depositing a photoresist material along an entire surface of the substrate; forming a photoresist pattern from the photoresist material using a diffraction mask, the photoresist pattern including a first part having a first thickness and a first width, a second part having a second thickness less than the first thickness, and a third part that exposes a first portion of the first conductive metal layer; etching the exposed first portion of the first conductive metal layer to remove the first portion of the first conductive metal layer, and etching a first portion of the silicon layer underlying the exposed first portion of the first conductive metal layer to remove the first portion of the silicon layer; simultaneously removing the second part of the photoresist pattern to expose a second portion of the first conductive metal layer, reducing the first thickness of the first part of the photoresist pattern to a third thickness, and reducing the first width of the first part of the photoresist pattern to a second width to expose lateral regions of a third portion of the first conductive metal layer; etching the exposed lateral regions of the third portion of the first conductive metal layer using the second width of the first part of the photoresist pattern as a mask and completely removing the second portion of the first conductive metal layer to form the active pattern and the data line; and removing the second width of the first part of the photoresist pattern; 19. The method according to claim 18, wherein the simultaneously removing the second part of the photoresist pattern, reducing the first thickness of the first part of the photoresist pattern, and reducing the first width of the first part of the photoresist pattern includes an ashing process. 20. The method according to claim 18, wherein the first insulating layer includes a silicon oxidation layer, and the second insulating layer includes a silicon nitride layer. 21. The method according to claim 18, wherein the silicon layer includes a crystallized silicon thin film. 22. The method according to claim 18, further comprising the step of injecting impurity ions into predetermined regions of the active pattern using the gate electrode as a mask to form a source region and a drain region within the active pattern. 23. The method according to claim 22, wherein the impurity ions include Group V impurities. 24. The method according to claim 22, wherein the impurity ions include Group III impurities. 25. The method according to claim 18, wherein the source electrode and the drain electrode include transparent conductive material. 26. The method according to claim 18, wherein a portion of the drain electrode extends towards a pixel region to form a pixel electrode. 27. The method according to claim 18, wherein first insulating layer directly contacts the active pattern and the data line, and the second insulating layer exclusively overlaps the data line. 28. A liquid crystal display device, comprising: an active pattern and a data line formed on a substrate; a first insulating layer on the substrate; a second insulating layer on the first insulating layer above the data line; a gate electrode formed on the first insulating layer above the active pattern; a third insulating layer formed on the substrate; first and second contact holes extending through the first and third insulating layers to expose first and second portions of the active pattern, respectively; a third contact hole extending through the first, second, and third insulating layers to expose a portion of the data line; a source electrode formed on the third insulating layer, the source electrode having a first portion within the first contact hole to contact the exposed first portion of the active pattern and a second portion within the third contact hole to contact the exposed portion of the data line; and a drain electrode formed on the third insulating layer, the drain electrode having a first portion within the second contact hole to contact the exposed second portion of the active pattern and a second portion extending into a pixel region of the liquid crystal display device. 29. The device according to claim 28, wherein the active pattern includes a first portion of silicon layer, and the data line is a double layer structure including a second portion of the silicon layer and a conductive metal material on the second portion of the silicon layer. 30. The device according to claim 28, wherein the source electrode and the drain electrode include transparent conductive material. 31. The device according to claim 30, wherein the transparent conductive material includes one indium-tin-oxide and indium-zinc-oxide. 32. The device according to claim 28, wherein the portion of the drain that extends into the pixel region is a pixel electrode. 33. The device according to claim 28, wherein first insulating layer directly contacts the active pattern and the data line, and the second insulating layer exclusively overlaps the data line.
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The present invention claims the benefit of Korean Patent Application No. 2003-095760, filed in Korea on Dec. 23, 2003, which is hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and a method of fabricating a display device, and more particularly, to a liquid crystal display (LCD) device and a method of fabrication an LCD device. 2. Description of the Related Art As the need for visual display devices increases, requirements for improved display devices having low power consumption, thin profiles, light weight, and high image quality has increased. One example of an improved display device is an LCD device that is suitable for mass-production. Accordingly, the LCD device has been developed to replace conventional cathode ray tube (CRT) devices. In general, an LCD device displays images by adjusting light transmittance ratios of liquid crystal cells by respectively supplying data signals according to image information to the liquid crystal cells arranged as a matrix configuration. Accordingly, the LCD device includes a color filter substrate, an array substrate, and a liquid crystal material layer formed between the color filter and array substrates. In addition, a thin film transistor (TFT) is commonly used as a switching device of the LCD device, wherein the TFT includes one of amorphous or polycrystalline silicon as a channel layer. During fabrication of the LCD device, a great number of mask processes (that is, a photolithography process) are required to fabricate the array substrate including the thin film transistor. Thus, to more efficiently produce LCD devices, there is a need to reduce the number of the mask processes. FIG. 1 is a partial plan view of an array substrate for an LCD device according to the related art. In FIG. 1, a plurality of gate lines 16 and data lines 17 are arranged on an array substrate 10 along first and second directions, respectively, to define a plurality of pixel regions. In addition, a thin film transistor (TFT) is formed at each crossing of the gate and data lines 16 and 17 and a pixel electrode 18 is formed at each of the pixel regions. The TFT includes a gate electrode 21 connected to the gate line 16, a source electrode 22 connected to the data line 17, and a drain electrode 23 connected to the pixel electrode 18. In addition, although not shown, the TFT includes first and second insulating layers for insulating the gate electrode 21 and the source/drain electrodes 22 and 23. Furthermore, the TFT includes an active layer 24 that includes a conductive channel between the source electrode 22 and the drain electrode 23 by application of a gate voltage to the gate electrode 21. In FIG. 1, the source electrode 22 is electrically connected to a source region of the active layer 24 through a first contact hole 40a formed on the insulating layers (not shown), and the drain electrode 23 is electrically connected to a drain region of the active layer 24 through the first contact hole 40a. Although not shown, a third insulating layer is provided with a second contact hole 40b formed on the drain electrode 23, wherein the drain electrode 23 and the pixel electrode 18 are electrically connected to each other through the second contact hole 40b. Hereinafter, a fabrication process of a general liquid crystal display device will be described in more detail with reference to FIGS. 2A to 2F. FIGS. 2A to 2F are cross sectional views along I-I′ of FIG. 1 of a method for fabricating an LCD device according to the related art. In FIG. 2A, an active pattern 24 composed of a polycrystalline silicon layer is formed on the substrate 10 using a photolithographic process. In FIG. 2B, a first insulating layer 15a and a conductive metal layer are sequentially deposited along an entire surface of the substrate 10 where the active pattern 24 is formed. Then, the conductive metal material is patterned by using a photolithographic process; thereby forming a gate electrode 21 on the active pattern 24 with the first insulating layer 15a interposed therebetween. Next, high concentration impurity ions are injected into predetermined regions of the active pattern 24 using the gate electrode 21 as a mask, thereby forming p+ or n+ type source/drain regions 24a and 24b. In FIG. 2C, a second insulating layer 15b is deposited along an entire surface of the substrate 10 where the gate electrode 21 is formed, and the second and first insulating layers 15b and 15a are partially removed by a photolithographic process, thereby forming first contact holes 40a that partially expose the source/drain regions 24a and 24b. In FIG. 2D, a conductive metal material is deposited along an entire surface of the substrate 10 and a photolithographic process is performed to forming a source electrode 22 connected to the source region 24a and a drain electrode 23 connected to the drain region 24b through the first contact hole 40a. In addition, a portion of the conductive metal layer constituting the source electrode 22 is extended along one direction to form a data line 17. In FIG. 2E, a third insulating layer 15c is deposited along an entire surface of the substrate 10, and a second contact hole 40b is formed by a photolithographic process to expose a part of the drain electrode 23. In FIG. 2F, a transparent conductive material is deposited along an entire surface of the substrate 10 where the third insulating layer 15c is formed, and a pixel electrode 18 connected to the drain electrode 23 through the second contact hole 40b is formed by a photolithographic process. During the fabrication method of the LCD device, at least six separate photolithographic processes are required to pattern the active pattern, the gate electrode, the first contact hole, the source/drain electrode, the second contact hole, and the pixel electrode. Each of the six photolithographic processes includes a series of processes for forming a desired pattern by transferring a pattern formed on a mask onto a substrate where a thin film is deposited. Then, a plurality of processes including photoresist deposition, light exposure, and a development process are performed. Accordingly, these photolithographic processes reduce production yield and may generate defects during formation of the TFT. In addition, since masks for forming the various patterns are very expensive, when the number of masks used during the fabrication processes increases, fabrication costs of the LCD device proportionally increases. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to an LCD device and a method of fabricating an LCD device that substantially obviates one or more the problems due to limitations and disadvantages of the related art. An object of the present invention is to provide an LCD device fabricated using a reduced number of fabrication processes. Another object of the present invention is to provide a method of fabricating an LCD device having a reduced number of fabrication processes. To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method of fabricating a liquid crystal display device includes forming an active pattern and a data line on a substrate, forming a first insulating layer on the data line, forming a second insulating layer on the substrate, forming a gate electrode on the second insulating layer above the active pattern, forming a third insulating layer on the substrate, forming first and second contact holes through the second and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively, and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the first exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole. In another aspect, a liquid crystal display device includes an active pattern and a data line formed on a substrate, a first insulating layer on the data line, a second insulating layer on the substrate, a gate electrode formed on the second insulating layer above the active pattern, a third insulating layer formed on the substrate, first and second contact holes extending through the second and third insulating layers to expose first and second portions of the active pattern, respectively, a third contact hole extending through the first, second, and third insulating layers to expose a portion of the data line, a source electrode formed on the third insulating layer, the source electrode having a first portion within the first contact hole to contact the exposed first portion of the active pattern and a second portion within the third contact hole to contact the exposed portion of the data line, and a drain electrode formed on the third insulating layer, the drain electrode having a first portion within the second contact hole to contact the exposed second portion of the active pattern and a second portion extending into a pixel region of the liquid crystal display device. In another aspect, a method of fabricating a liquid crystal display device includes forming an active pattern and a data line on a substrate, forming a first insulating layer on the substrate, forming a second insulating layer overlying the first insulating layer above the data line, forming a gate electrode on the first insulating layer above the active pattern, forming a third insulating layer on the substrate, forming first and second contact holes through the first and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively, and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole. In another aspect, a liquid crystal display device includes an active pattern and a data line formed on a substrate, a first insulating layer on the substrate, a second insulating layer on the first insulating layer above the data line, a gate electrode formed on the first insulating layer above the active pattern, a third insulating layer formed on the substrate, first and second contact holes extending through the first and third insulating layers to expose first and second portions of the active pattern, respectively, a third contact hole extending through the first, second, and third insulating layers to expose a portion of the data line, a source electrode formed on the third insulating layer, the source electrode having a first portion within the first contact hole to contact the exposed first portion of the active pattern and a second portion within the third contact hole to contact the exposed portion of the data line, and a drain electrode formed on the third insulating layer, the drain electrode having a first portion within the second contact hole to contact the exposed second portion of the active pattern and a second portion extending into a pixel region of the liquid crystal display device. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings: FIG. 1 is a partial plan view of an array substrate for an LCD device according to the related art; FIGS. 2A to 2F are cross sectional views along I-I′ of FIG. 1 of a method for fabricating an LCD device according to the related art; FIG. 3 is a plan view of an exemplary array substrate for an LCD device according to the present invention; FIGS. 4A to 4E are cross sectional views along III-III′ of FIG. 3 of an exemplary method of fabricating an LCD according to the present invention; FIGS. 5A to 5C are cross sectional views of an exemplary method of fabricating an active pattern and data line of FIG. 4B according to the present invention; FIGS. 6A to 6F are cross sectional views of another exemplary method of fabricating an LCD device according to the present invention; and FIGS. 7A to 7C are cross sectional views of an exemplary method of fabricating an active pattern and data line of FIG. 6B according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. FIG. 3 is a plan view of an exemplary array substrate for an LCD device according to the present invention. Although FIG. 3 may show a single pixel, a matrix configuration of an N-number of gate lines and an M-number of data lines may be provided, thereby forming an N×M matrix configuration of pixels. In FIG. 3, an array substrate 110 may include a pixel electrode 118 formed on a pixel region, a gate line 116 and a data line 117 arranged along horizontal and vertical directions on the substrate 110, respectively, and a TFT formed at an intersection region of the gate and data lines 116 and 117 to function as a switching device. The TFT may include a gate electrode 121 connected to the gate line 1.16, a source electrode 122 connected to the data line 117, and a drain electrode 123 connected to the pixel electrode 118. In addition, although not shown, the TFT may include first and second insulating layers for insulating the gate electrode 121 and the source/drain electrodes 122 and 123. Furthermore, the TFT may include an active layer 124 for creating a conductive channel between the source electrode 122 and the drain electrode 123 by an applied gate voltage to the gate electrode 121. In FIG. 3, a portion of the source electrode 122 may be electrically connected to a source region of the active layer 124 through a first contact hole 140a formed through the second insulating layer and a third insulating layer (not shown). In addition, a portion of the drain electrode 123 may be electrically connected to a drain region of the active layer 124 through a first contact hole 140a. Accordingly, a portion of the source electrode 122 may constitute a connection electrode 150 that may be electrically connected to the data line 117 through the second contact hole 140b formed through the first insulating layer (not shown), the second insulating layer (not shown), and the third insulating layer (not shown). In addition, a portion of the drain electrode 123 may extend towards the pixel region to constitute the pixel electrode 118. The pixel electrode 118 may be formed during patterning of the source/drain electrodes 122 and 123, thereby reducing a total number of masks used for fabricating the TFT. FIGS. 4A to 4E are cross sectional views along III-III′ of FIG. 3 of an exemplary method of fabricating an LCD according to the present invention. In FIG. 4A, a silicon layer 120 may be formed on a transparent substrate 110 formed of a transparent insulating material, such as glass. Although not shown, a buffer layer composed of a silicon oxidation layer (SiO2) may be formed on the substrate 110, and then the silicon layer 120 may be formed on the buffer layer. The buffer layer may prevent impurities, such as Na, from migrating (leaching) from the transparent substrate 110 into upper layers during subsequent fabrication processes. The silicon layer 120 may include one of an amorphous silicon thin film and a polycrystalline silicon thin film. For purposes of explanation, the silicon layer 120 may be formed of the polycrystalline silicon thin film. The polycrystalline silicon thin film may be formed by using one of several different crystallization methods after depositing an amorphous silicon thin film on the substrate 110. One method includes depositing amorphous silicon thin film by several different methods, such as low pressure chemical vapor deposition (LPCVD) and plasma enhanced chemical vapor deposition (PECVD). Then, a dehydrogenation process may be performed to remove hydrogen within the amorphous silicon thin film, and then crystallization of the amorphous silicon thin film may be performed. For example, the method for crystallizing the amorphous silicon thin film may include a solid phase crystallization (SPC) method and an excimer laser annealing (ELA) method using a laser. During the ELA method, a laser annealing method may include a laser pulse. Alternatively, a sequential lateral solidification (SLS) method may be used to improve crystallization characteristics by growing grains along a horizontal direction. The SLS method make use of grain growth along a vertical direction of an interface between liquid phase silicon and solid phase silicon. Accordingly, the SLS method improves sizes of silicon grains by laterally growing the grains along a predetermined length by properly controlling an amount of laser energy and an irradiation range of a laser beam. In FIG. 4A, a first conductive metal layer 130, such as Al, Al alloy, W, Cu, Cr, and Mo, may be formed on the polycrystalline silicon thin film 120. In FIG. 4B, the first conductive metal layer 130 and the polycrystalline silicon thin film 120 may be simultaneously patterned, thereby forming the data line 117 surrounded by a first insulating layer 115a and an active pattern 124. FIGS. 5A to 5C are cross sectional views of an exemplary method of fabricating an active pattern and data line of FIG. 4B according to the present invention. In FIG. 5A, the first conductive metal layer 130 and the polycrystalline silicon thin film 120 may be patterned by using a photolithographic process to form the active pattern 124 and the data line 117. Accordingly, a first conductive metal pattern 130a may have the same form as the active pattern 124, and may remain on the active pattern 124. In FIG. 5B, in order to remove the first conductive metal pattern 130a remaining on the active pattern 124, a first insulating layer 115a and a second conductive metal layer 135 may be sequentially formed along an entire surface of the substrate 110. For example, the second conductive metal layer 135 may be formed of the same material as the first conductive metal pattern 130a remaining on the active pattern 124 both having the same thickness. Alternatively, the second conductive metal layer 135 and the first conductive metal pattern 130a may be formed of different materials both having different thicknesses. Accordingly, when the second conductive metal layer 135 is formed of a material different from that of the first conductive metal pattern 130a, the thickness of the second conductive metal layer 135 may be controlled so that the first conductive metal pattern 130a may be completely removed by a subsequent etching process. In FIG. 5C, the second conductive metal layer 135 and the first insulating layer 115a may be patterned using a mask having the same pattern as the data line 117 and the mask may have a width larger than the data line 117, thereby forming a second conductive metal pattern 135a on the data line 117 with the first insulating layer 115a interposed therebetween. Then, the first conductive metal pattern 130a and the second conductive metal pattern 135a may be simultaneously removed, thereby exposing the active pattern 124. In FIG. 4C, a second insulating layer 115b, which may function as a gate insulating layer, may be deposited along an entire surface of the substrate 110. The second insulating layer 115b may be formed to be thinner than the first insulating layer 115a. Then, a gate electrode 121 of a conductive metal material may be formed on the active pattern 124 where the second insulating layer 115b may be formed. Next, impurity ions may be injected into predetermined regions of the active pattern 124 by using the gate electrode 121 as a mask, thereby forming a source region 124a and a drain region 124b. Accordingly, the gate electrode 121 may function as an ion stopper that prevents dopant ions from pentrating into a channel region of the active pattern 124. In FIG. 4C, electric characteristics of the active pattern 124 may be varied according to the type of injected impurity ions. For example, if the injected impurity ions correspond to the third group of the Periodic Table (Group III), such as boron B, then the active pattern 124 may function as a P-type TFT. Conversely, if the injected impurity ions correspond to the fifth group of the Periodic Table (Group V), such as phosphorus P, then the active pattern 124 may function as an N-type TFT. After the impurity ion injection process, a process for activating the injected impurity ions may be performed. Although not shown, the gate line 116 (in FIG. 3) may be formed along a vertical direction to the data line 117 during the formation of the gate electrode 121. If the first insulating layer 115a is formed on the data line 117 having a sufficient thickness with respect to the thickness of the second insulating layer 115b, then signal interference at the intersection regions between the data line 117 and the gate line 116 may be prevented. In FIG. 4D, a third insulating layer 115c may be deposited along an entire surface of the substrate 110 where the gate electrode 121 may be formed, wherein the third insulating layer 115c may be formed of a transparent organic insulating material, such as benzocyclobutene (BCB) or acryl resin, for providing a high aperture ratio. Then, the third insulating layer 115c and the second insulating layer 115b may be partially removed by a photolithographic process, thereby forming first contact holes 140a that may partially expose a source region 124a and a drain region 124b of the TFT. Then, the third insulating layer 115c, the second insulating layer 115b, and the first insulating layer 115a may be partially removed, thereby forming a second contact hole 140b that may partially expose the data line 117. Although not shown, after patterning the third insulating layer 115c, a conductive metal layer may be deposited on the photoresist pattern and at inner portions of the first contact holes 140a and the second contact hole 140b, wherein the photoresist pattern used during the patterning may not be removed. In addition, the conductive metal layer may remain on the exposed source/drain region 124a and 124b and on the data line 117 using a lift-off process for removing the photoresist pattern. using a stripper solution. Accordingly, by forming the conductive metal layer, contact resistance with a subsequently-formed transparent electrode may be reduced. The lift-off process may reduce contact resistance between electrodes by forming a barrier metal layer on the surface of the exposed electrodes of a lower layer, i.e., the exposed source/drain regions 124a and 124b, and the data line 117, by using the photoresist pattern used during the patterning without using an additional mask. In FIG. 4E, a transparent conductive material having excellent transmissivity, such as indium tin oxide (ITO) or indium zinc oxide (IZO), may be deposited along an entire surface of the substrate 110. Then, a source electrode 122 connected to the source region 124a through the first contact hole 140a and a drain electrode 123 connected to the drain region 124b through the first contact hole 140a may be formed by a photolithographic process. Accordingly, a portion of the source electrode 122 may constitute a connection electrode 150 for electrically connecting the source region 124a and the data line 117 through the second contact hole 140b. In addition, a portion of the drain electrode 123 may extend toward the pixel region to form the pixel electrode 118. According to the present invention, the active pattern and the data line may be simultaneously patterned to form the first contact hole and the second contact hole during a single process. In addition, a portion of the drain electrode may constitute the pixel electrode, thereby reducing a total number of process masks. Accordingly, fabrication processes are simplified and production yield may be increased and fabrication costs may be reduced. Another embodiment for forming the active pattern and the data line by using a diffraction exposure will be explained as follows. FIGS. 6A to 6F are cross sectional views of another exemplary method of fabricating an LCD device according to the present invention. In FIG. 6A, a polycrystalline silicon thin film 220 may be formed on a transparent substrate 210, such as glass. Then, a conductive metal layer 230 may be formed on the polycrystalline silicon thin film 220, and a photosensitive material 270, such as a photoresist, may be deposited with a predetermined thickness on the conductive metal layer 230. The photoresist may include a positive photoresist, such as a NOVOLAK-based resin, wherein regions exposed to light react with a developer to dissolve the light-exposed regions. Alternatively, the photoresist may include a negative photoresist of an acryl-based monomer, wherein regions not exposed to light may react with a developer to dissolve the light-shield regions. The photoresist may include one of a solvent for controlling viscosity, a photoactive-based compound for creating photosensitization, and a resin that includes a chemical binding material. In FIG. 6B, the conductive metal layer 230 and the polycrystalline silicon thin film 220 may be patterned by applying a diffraction mask to the photoresist 270, thereby forming a data line 217 on the polycrystalline silicon thin film 220 and forming an active pattern 224. FIGS. 7A to 7C are cross sectional views of an exemplary method of fabricating an active pattern and data line of FIG. 6B according to the present invention. In FIG. 7A, a diffraction mask may be positioned on the substrate 210 where the photoresist 270 may be deposited. Then, UV light may be transmitted through the diffraction mask onto the photoresist 270. Although positive or negative photoresists may be used, according to the present invention, a negative photoresist 270 may be used. When using the negative photoresist 270, a photolithographic process may be performed by using the diffraction mask that may include a first region I that may be a completely open pattern to allow the photoresist 270 to be exposed to the UV light such that the photoresist 270 may completely remain, a second region II that may have a slit-type open pattern to allow the photoresist 270 to be partially exposed to the UV light such that the photoresist 270 may have a reduced thickness, and a third region III that may be completely solid to prevent the photoresist 270 from being exposed to the UV light, i.e., shielded such that the photoresist may be completely removed. Within the second region II of the diffraction mask, the slit-type open pattern may diffract the incident UV light to reduce an intensity of the UV light incident on the substrate 210. In addition, the slit-type open pattern may include a specific slit gap that may be narrower than a resolution of the UV light source. According to the present invention, although the slit-type open pattern may be used within the second region II, a semi-transmissivity layer may be used. In FIG. 7A, by using the diffraction mask to perform the photolithographic process, a first photoresist pattern 270a of a first thickness may remain within the first region I, a second photoresist pattern 270b of a second thickness less than the first thickness may be formed within the second region II, and no photoresist pattern may be formed within the third region III. Accordingly, the conductive metal layer 230 and the polycrystalline silicon thin film 220 of the third region III where the first and second photoresist patterns 270a and 270b are not formed may be removed, thereby forming an active pattern 224 and a data line 217. In addition, a conductive metal pattern 230a and the second photoresist pattern 270b of the second thickness may remain on the active pattern 224. In FIG. 7B, a portion of the first photoresist pattern 270a may be removed by an ashing process, wherein the photoresist material may be oxidized using oxygen gas. Accordingly, reduction of the first thickness of the first photoresist pattern 270a on the data line 217 may be precisely controlled, thereby forming a third photoresist pattern 270c of a third thickness. In addition, the second photoresist pattern 270b on the active pattern 224 may be completely removed, thereby exposing a surface of the conductive metal pattern 230a. In FIG. 7C, the conductive metals 217 and 230a may be patterned by using the third photoresist pattern 270c as a mask, thereby completely removing the conductive metal pattern 230a remaining on the active pattern 224. In FIG. 6C, a first insulating layer 215a may be deposited along an entire surface of the substrate 210. In addition, a second insulating layer 215b may be formed on the first insulating layer 215a, wherein the second insulating layer 215b may prevent signal interference at intersection regions of the gate and data lines 216 and 217. The first insulating layer 215a may be formed of a silicon oxidation layer at a first thickness, and the second insulating layer 215b may be formed of a silicon nitride layer with a second thickness greater than the first thickness of the first insulating layer 215a. Alternatively, the first insulating layer 215a may be formed of a silicon nitride layer, and the second insulating layer 215b may be formed of a silicon oxidation layer. Moreover, both the first insulating layer 215a and the second insulating layer 215b may be formed of a silicon oxidation layer or may be formed of a silicon nitride layer. Then, the second insulating layer 215b may be selectively etched by using a mask having the same pattern as the data line 217 and having a width larger than a width of the data line 217. For example, when the first insulating layer 215a is formed of a silicon oxidation layer and the second insulating layer 215b is formed of a silicon nitride layer, a selective etching according to differences of etching ratios between the silicon oxidation layer and the silicon nitride layer may be performed. Accordingly, only the second insulating layer 215b may be removed on the active pattern 224. In FIG. 6D, a gate electrode 221 may be formed of a conductive metal material on the active pattern 224 where the first insulating layer 215a may be formed. Then, impurity ions may be injected into predetermined regions of the active pattern 224 by using the gate electrode 221 as a mask, thereby forming a source region 224a and a drain region 224b. In FIG. 6E, a third insulating layer 215c may be deposited along an entire surface of the substrate 210 where the gate electrode 221 may be formed. Then, the third insulating layer 215c and the first insulating layer 215a may be partially removed by a photolithographic process to form first contact holes 240a that may expose portions of the source region 224a and the drain region 224b. In addition, the third insulating layer 215c, the second insulating layer 215b, and the first insulating layer 215a may be partially removed, thereby forming a second contact hole 240b that may expose a portion of the data line 217. In FIG. 6F, a transparent conductive material may be deposited along an entire surface of the substrate 210. Then, the transparent conductive material may be patterned using a photolithographic process to form a source electrode 222 connected to the source region 224a through the first contact hole 240a and a drain electrode 223 connected to the drain region 224b through the first contact hole 240a. In addition, a portion of the source electrode 222 may constitute a connection electrode 250 for electrically connecting the source region 224a and the data line 217 through the second contact hole 240b. Furthermore, a portion of the drain electrode 223 may extend towards a pixel region, thereby forming a pixel electrode 218. It will be apparent to those skilled in the art that various modifications and variation can be made in the LCD device and method of fabricating an LCD device of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a display device and a method of fabricating a display device, and more particularly, to a liquid crystal display (LCD) device and a method of fabrication an LCD device. 2. Description of the Related Art As the need for visual display devices increases, requirements for improved display devices having low power consumption, thin profiles, light weight, and high image quality has increased. One example of an improved display device is an LCD device that is suitable for mass-production. Accordingly, the LCD device has been developed to replace conventional cathode ray tube (CRT) devices. In general, an LCD device displays images by adjusting light transmittance ratios of liquid crystal cells by respectively supplying data signals according to image information to the liquid crystal cells arranged as a matrix configuration. Accordingly, the LCD device includes a color filter substrate, an array substrate, and a liquid crystal material layer formed between the color filter and array substrates. In addition, a thin film transistor (TFT) is commonly used as a switching device of the LCD device, wherein the TFT includes one of amorphous or polycrystalline silicon as a channel layer. During fabrication of the LCD device, a great number of mask processes (that is, a photolithography process) are required to fabricate the array substrate including the thin film transistor. Thus, to more efficiently produce LCD devices, there is a need to reduce the number of the mask processes. FIG. 1 is a partial plan view of an array substrate for an LCD device according to the related art. In FIG. 1 , a plurality of gate lines 16 and data lines 17 are arranged on an array substrate 10 along first and second directions, respectively, to define a plurality of pixel regions. In addition, a thin film transistor (TFT) is formed at each crossing of the gate and data lines 16 and 17 and a pixel electrode 18 is formed at each of the pixel regions. The TFT includes a gate electrode 21 connected to the gate line 16 , a source electrode 22 connected to the data line 17 , and a drain electrode 23 connected to the pixel electrode 18 . In addition, although not shown, the TFT includes first and second insulating layers for insulating the gate electrode 21 and the source/drain electrodes 22 and 23 . Furthermore, the TFT includes an active layer 24 that includes a conductive channel between the source electrode 22 and the drain electrode 23 by application of a gate voltage to the gate electrode 21 . In FIG. 1 , the source electrode 22 is electrically connected to a source region of the active layer 24 through a first contact hole 40 a formed on the insulating layers (not shown), and the drain electrode 23 is electrically connected to a drain region of the active layer 24 through the first contact hole 40 a . Although not shown, a third insulating layer is provided with a second contact hole 40 b formed on the drain electrode 23 , wherein the drain electrode 23 and the pixel electrode 18 are electrically connected to each other through the second contact hole 40 b. Hereinafter, a fabrication process of a general liquid crystal display device will be described in more detail with reference to FIGS. 2A to 2 F. FIGS. 2A to 2 F are cross sectional views along I-I′ of FIG. 1 of a method for fabricating an LCD device according to the related art. In FIG. 2A , an active pattern 24 composed of a polycrystalline silicon layer is formed on the substrate 10 using a photolithographic process. In FIG. 2B , a first insulating layer 15 a and a conductive metal layer are sequentially deposited along an entire surface of the substrate 10 where the active pattern 24 is formed. Then, the conductive metal material is patterned by using a photolithographic process; thereby forming a gate electrode 21 on the active pattern 24 with the first insulating layer 15 a interposed therebetween. Next, high concentration impurity ions are injected into predetermined regions of the active pattern 24 using the gate electrode 21 as a mask, thereby forming p+ or n+ type source/drain regions 24 a and 24 b. In FIG. 2C , a second insulating layer 15 b is deposited along an entire surface of the substrate 10 where the gate electrode 21 is formed, and the second and first insulating layers 15 b and 15 a are partially removed by a photolithographic process, thereby forming first contact holes 40 a that partially expose the source/drain regions 24 a and 24 b. In FIG. 2D , a conductive metal material is deposited along an entire surface of the substrate 10 and a photolithographic process is performed to forming a source electrode 22 connected to the source region 24 a and a drain electrode 23 connected to the drain region 24 b through the first contact hole 40 a . In addition, a portion of the conductive metal layer constituting the source electrode 22 is extended along one direction to form a data line 17 . In FIG. 2E , a third insulating layer 15 c is deposited along an entire surface of the substrate 10 , and a second contact hole 40 b is formed by a photolithographic process to expose a part of the drain electrode 23 . In FIG. 2F , a transparent conductive material is deposited along an entire surface of the substrate 10 where the third insulating layer 15 c is formed, and a pixel electrode 18 connected to the drain electrode 23 through the second contact hole 40 b is formed by a photolithographic process. During the fabrication method of the LCD device, at least six separate photolithographic processes are required to pattern the active pattern, the gate electrode, the first contact hole, the source/drain electrode, the second contact hole, and the pixel electrode. Each of the six photolithographic processes includes a series of processes for forming a desired pattern by transferring a pattern formed on a mask onto a substrate where a thin film is deposited. Then, a plurality of processes including photoresist deposition, light exposure, and a development process are performed. Accordingly, these photolithographic processes reduce production yield and may generate defects during formation of the TFT. In addition, since masks for forming the various patterns are very expensive, when the number of masks used during the fabrication processes increases, fabrication costs of the LCD device proportionally increases.
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<SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, the present invention is directed to an LCD device and a method of fabricating an LCD device that substantially obviates one or more the problems due to limitations and disadvantages of the related art. An object of the present invention is to provide an LCD device fabricated using a reduced number of fabrication processes. Another object of the present invention is to provide a method of fabricating an LCD device having a reduced number of fabrication processes. To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method of fabricating a liquid crystal display device includes forming an active pattern and a data line on a substrate, forming a first insulating layer on the data line, forming a second insulating layer on the substrate, forming a gate electrode on the second insulating layer above the active pattern, forming a third insulating layer on the substrate, forming first and second contact holes through the second and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively, and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the first exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole. In another aspect, a liquid crystal display device includes an active pattern and a data line formed on a substrate, a first insulating layer on the data line, a second insulating layer on the substrate, a gate electrode formed on the second insulating layer above the active pattern, a third insulating layer formed on the substrate, first and second contact holes extending through the second and third insulating layers to expose first and second portions of the active pattern, respectively, a third contact hole extending through the first, second, and third insulating layers to expose a portion of the data line, a source electrode formed on the third insulating layer, the source electrode having a first portion within the first contact hole to contact the exposed first portion of the active pattern and a second portion within the third contact hole to contact the exposed portion of the data line, and a drain electrode formed on the third insulating layer, the drain electrode having a first portion within the second contact hole to contact the exposed second portion of the active pattern and a second portion extending into a pixel region of the liquid crystal display device. In another aspect, a method of fabricating a liquid crystal display device includes forming an active pattern and a data line on a substrate, forming a first insulating layer on the substrate, forming a second insulating layer overlying the first insulating layer above the data line, forming a gate electrode on the first insulating layer above the active pattern, forming a third insulating layer on the substrate, forming first and second contact holes through the first and third insulating layers to expose first and second portions of the active pattern, and forming a third contact hole through the first, second, and third insulating layers exposing a portion of the data line, respectively, and forming source and drain electrodes on the third insulating layer, the source electrode connected to the first exposed portion of the active pattern through the first contact hole and connected to the exposed portion of the data line through the third contact hole, and the drain electrode connected to the second exposed portion of the active pattern through the second contact hole. In another aspect, a liquid crystal display device includes an active pattern and a data line formed on a substrate, a first insulating layer on the substrate, a second insulating layer on the first insulating layer above the data line, a gate electrode formed on the first insulating layer above the active pattern, a third insulating layer formed on the substrate, first and second contact holes extending through the first and third insulating layers to expose first and second portions of the active pattern, respectively, a third contact hole extending through the first, second, and third insulating layers to expose a portion of the data line, a source electrode formed on the third insulating layer, the source electrode having a first portion within the first contact hole to contact the exposed first portion of the active pattern and a second portion within the third contact hole to contact the exposed portion of the data line, and a drain electrode formed on the third insulating layer, the drain electrode having a first portion within the second contact hole to contact the exposed second portion of the active pattern and a second portion extending into a pixel region of the liquid crystal display device. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
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20040629
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20070508
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20050623
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72809.0
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NGUYEN, DUNG T
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LIQUID CRYSTAL DISPLAY DEVICE AND METHOD OF FABRICATING THE SAME
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UNDISCOUNTED
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ACCEPTED
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10,878,477
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ACCEPTED
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Programmable calibration circuit for power supply current sensing and droop loss compensation
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A circuit for regulating power is disclosed. The present invention provides circuits and methods for current sensing variations, static droop settings, mismatched phase outputs, and temperature variations in a multiphase power regulator. The circuits may include a calibration controller that senses and regulates both a current sensing circuit and the droop in a power regulator over a range of temperatures thus equalizing phase outputs. The present invention includes the schematic organization and implementation of the circuit, the circuit's calibration, its use, and implementation. This invention advantageously provides circuits and methods to properly power a processor or IC chip according to the unique power specifications of the processor or chip.
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1. A circuit comprising: a regulator circuit and a calibration control circuit, wherein said calibration control circuit includes a controller, an interface with nonvolatile memory, droop outputs, sense outputs, load voltage input, and temperature input; wherein said nonvolatile memory stores calibration data; said calibration control circuit interfaces with said regulator circuit via said sense outputs, said droop outputs, and said load voltage input; said calibration control circuit interfaces with said nonvolatile memory to store calibration data; said calibration control circuit interfaces with said temperature input to receive temperature data; said temperature data is used by said calibration control circuit to adjust said sense outputs and said droop outputs; and said calibration control circuit interfaces with said temperature input and said load voltage input to calibrate said calibration data stored in said nonvolatile memory. 2. The circuit of claim 1 where said regulator circuit is selected from the group consisting of a voltage mode regulator, a current mode regulator, a buck regulator, V-square, and hysteretics. 3. The circuit of claim 1 where said regulator circuit is selected from the group consisting of a single phase regulator, a two phase regulator, multiphase regulator, and an N phase regulator, where N can be any integer from 1 to infinity. 4. The circuit of claim 3 where said controller has at least one sense output for each phase of said multiphase regulator. 5. The circuit of claim 1 where said calibration control circuit adjusts said sense outputs and said droop outputs according to data stored in said nonvolatile memory. 6. The circuit of claim 1 where said nonvolatile memory stores regulator performance parameters. 7. The circuit of claim 1 where said nonvolatile memory stores application specific power curve data. 8. The circuit of claim 1 where said nonvolatile memory is either monolithic or non monolithic. 9. The circuit of claim 1 where said nonvolatile memory stores data for said droop outputs and said sense outputs where said data is based on said load voltage input and said temperature input. 10. The circuit of claim 1 where each said sense output comprises a digital to analog converter with registered input and an amplifier buffer. 11. The circuit of claim 1 where said droop output comprises a digital to analog converter with registered input and an amplifier buffer. 12. The circuit of claim 1 where said calibration control circuit includes a temperature output comprising a digital to analog converter with registered input and an amplifier buffer. 13. The circuit of claim 1 where said load voltage input comprises an analog to digital converter with registered output. 14. The circuit of claim 1 where said temperature input comprises a temperature sensor, an amplifier, and an analog to digital converter with registered output. 15. The circuit of claim 14 where said temperature sensor is selected from the group consisting of a thermister, a thermocouple, and an RTD. 16. The circuit of claim 14 where said temperature sensor is either external or internal to the circuit. 17. The circuit of claim 14 wherein said calibration control circuit includes a temperature output, said amplifier is an adjustable amplifier, and said controller adjusts said adjustable amplifier via said temperature output. 18. The circuit of claim 1 where said calibration control circuit includes an external interface to an external controller. 19. The circuit of claim 18 where said external interface to an external controller allows said external controller to interface with said calibration control circuit, monitor said load voltage input, monitor said temperature input, control sense outputs, droop output, read said nonvolatile memory, and write to nonvolatile memory. 20. The circuit of claim 18 where said external controller is selected from a group consisting of a processor, a computer, and a state machine. 21. The circuit of claim 1 where said regulator circuit calibration data is stored in a lookup table within said nonvolatile memory. 22. The circuit of claim 1 where said controller is selected from the group consisting of a state machine and a processor. 23. The circuit of claim 1 where said calibration control circuit includes an error output. 24. The circuit of claim 23 where said error output comprises a digital to analog converter with registered input and an amplifier buffer. 25. The circuit of claim 24 where said calibration control circuit interfaces with said regulator via said error output. 26. The regulator circuit of claim 1 further comprising: a multiphase clock register, multiple phases, an adjustable droop amplifier, and an error circuit with an error amplifier, wherein each phase of said regulator include a set register, gate driver, output FETs, a current sense circuit, an adjustable sense amplifier, and a pulse width moderator; and wherein: said multiphase clock register has N phases, where N is an integer from 1 to infinity; said multiple phases are N phases, where N is an integer from 1 to infinity; a phase of said multiphase clock generator drives the set input of said set register; said set register drives said gate driver and said output FETs; said output FETs drive the load of the circuit; said current sense circuit measures the current of said output FETs and feeds back to said set register via said adjustable sense amplifier and said pulse width modulator; said adjustable sense amplifier also feeds into said adjustable droop amplifier; said droop amplifier drives said error circuit; and said error circuit drives each pulse width modulator on each said phase. 27. The circuit of claim 26 where said regulator includes an interface from said multiphase clock generator to an external controller. 28. The circuit of claim 27 where said external controller is selected from the group consisting of a computer, a state machine, and a processor. 29. The circuit of claim 26 where said regulator includes an interface to said calibration control circuit; wherein said calibration control circuit interfaces with said multiphase regulator by adjusting said sense amplifiers in each phase via said sense outputs, by adjusting said adjustable droop amplifier via said droop output, and by monitoring load voltage output of said current sense circuit via said load voltage input. 30. The circuit of claim 26 where said current sense circuit is selected from the group consisting of RDSon of a power MOSFETs, DCR of an inductor, sense series resistor, and board traces. 31. The circuit of claim 26 where said adjustable droop amplifier is adjusted to compensate for regulator circuit variations. 32. The circuit of claim 26 where said adjustable sense amplifier is adjusted to compensate for regulator circuit variations. 33. The circuit of claim 26 where said error circuit includes an adjustable amplifier. 34. The circuit of claim 33 where said adjustable error amplifier is adjusted to compensate for regulator circuit variations. 35. The circuit of claim 34 where said calibration control circuit includes an error output that interfaces with said adjustable error amplifier. 36. The circuit of claim 34 where said adjustable error amplifier is adjusted to compensate for error circuit variations. 37. A circuit comprising: a multiphase clock register, multiple phases, an adjustable droop amplifier, and an error circuit with an error amplifier, wherein each phase of said regulator include a set register, gate driver, output FETs, a current sense circuit, an adjustable sense amplifier, and a pulse width moderator; and wherein: said multiphase clock register has N phases, where N is an integer from 1 to infinity; said multiple phases are N phases, where N is an integer from 1 to infinity; a phase of said multiphase clock generator drives the set input of said set register; said set register drives said gate driver and said output FETs; said output FETs drive the load of the circuit; said current sense circuit measures the current of said output FETs and feeds back to said set register via said adjustable sense amplifier and said pulse width modulator; said adjustable sense amplifier also feeds into said adjustable droop amplifier; said droop amplifier drives said error circuit; and said error circuit drives each pulse width modulator on each said phase. 38. The circuit of claim 37 where said multiphase regulator includes an interface from the multiphase clock generator to an external controller. 39. The circuit of claim 37 where said current sense circuit is selected from the group consisting of RDSon of a power MOSFETs, DCR of an inductor, sense series resistor, and board traces. 40. The circuit of claim 37 where said adjustable droop amplifier is adjusted to compensate for regulator circuit variations. 41. The circuit of claim 37 where said adjustable sense amplifier is adjusted to compensate for regulator circuit variations. 42. The circuit of claim 37 where said error circuit comprises a comparator and an amplifier. 43. The circuit of claim 42 where said error amplifier is an adjustable amplifier. 44. The circuit of claim 43 where said adjustable error amplifier is adjusted to compensate for regulator circuit variations. 45. The circuit of claim 37 where the load is selected from the group consisting of a processor, memory, flash, and an integrated circuit. 46. The circuit of claim 37 where said load is selected from the group consisting of the Intel Pentium® series processors, the Intel Centrino® series processors, the Intel Express® series processors, the Intel Xenon® series processors, the Intel Celeron® series processors, the AMD Athlon® series processors, the AMD Duron® series processors, the AMD K6® series processors, the AMD Opteron® series processors, or the Power PC Sonnet® series processors. 47. A method of calibrating a calibration control circuit connected with a regulator supplying power to a load, comprising the steps of: estimating anticipated operation specifications of said load; creating a set of output data based on said estimate; storing said output data in nonvolatile memory; placing said regulator and said calibration control circuit in a circuit with said load; sampling calibration control circuit inputs from load voltage input at the interface between said regulator; sampling calibration control circuit temperature input; adjusting sense outputs of said calibration control circuit until input load voltage meets load operation specifications; adjusting droop output of said calibration control circuit until input load voltage meets load operation specifications; creating output data that relates temperature input with sense outputs and temperature data with droop output; and storing the created output in nonvolatile memory; wherein one or more said steps may be performed in any appropriate order. 48. The method of claim 47 wherein the regulator is a multiphase regulator. 49. The method of claim 47 wherein the method is repeated at different operating temperatures. 50. The circuit of claim 47 wherein said nonvolatile memory is either monolithic or non monolithic. 51. The method of claim 47 wherein said output data is stored in a look up table. 52. The method of claim 47 wherein the method is repeated with different loads. 53. The method of claim 47 wherein said method is controlled and monitored via an external interface. 54. The method of claim 47 where the calibration control circuit and the regulator are part of the same circuit. 55. The method of claim 47 wherein said load voltage is measured with external measurement equipment, said output data is created externally, and said output data is transferred to said calibration control circuit. 56. The method of claim 47 wherein said calibration control circuit is controlled by an external controller that is selected from the set consisting of a processor, a computer, and a state machine. 57. The method of claim 47 wherein the regulator is a multiphase regulator and the method is repeated for each phases of said multiphase regulator. 58. The method of claim 57 wherein the method is repeated at different operating temperatures. 59. The method of claim 47 wherein the method is repeated with different loads. 60. The method of claim 47 wherein said calibration control circuit and said regulator are included in one control regulator. 61. The method of claim 60 wherein said control regulator is selected from a plurality of control regulator and said load is a chip selected from a plurality of chips, such that said chip is said load of said control regulator, wherein said calibration allows each control regulator to power each chip according to said chip's unique power requirements. 62. The method of claim 61 wherein said chips are selected from the group consisting of processors, RAM, controllers, and processors. 63. The method of claim 61 wherein said control regulator is selected from the group consisting of a single phase regulator, a two phase regulator, multiphase regulator, and an N phase regulator, where N can be any integer number from 1 to infinity. 64. A method of using a calibration control circuit comprising the steps of: receiving temperature data from temperature input; referencing memory for stored calibration data associated with said temperature data; setting sense output values of said calibration control circuit according said calibrated data; and setting droop output values of said calibration control circuit according to said calibrated data; wherein one or more said steps can be performed in any appropriate order. 65. The method of claim 64 wherein the method is continuously repeated at set intervals of time. 66. The method of claim 64 wherein the calibrated control regulator controls multiple phases and the method is repeated for multiple phases of said 67. The method of claim 64 where said each sense output is connected to a sense amplifier of said regulator circuit and said droop output is connected to droop amplifier of said regulator circuit.
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CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit, under 35 U.S.C. §119, of U.S. provisional Application Ser. No. 60/484,105, filed 30 Jun. 2003, the entire contents and substance of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION Multi-phase voltage regulators are commonly used over single-phase regulators because they produce higher current output, faster transient responses, and more efficient applications in microprocessor power supplies. Due to discrete components and power device mismatches, the load current is not always equally shared among all the phases of multi-phase regulators causing inadequate operation and excessive heat in the power devices of one or more phases of a multi-phase power supply. To overcome this problem, active current sharing may be utilized to force current equalization among all phases. This requires a current sensing circuit. Since sense resistors are both inefficient and expensive, other resistive elements such as RDSon of the power MOSFETs, DCR of the inductor, and board traces are used to measure the source current for each phase of the power supply. These elements have a high degree of variation from one to another over changing environmental conditions and over production lot variations. Historically, using these elements to sense current causes a mismatch in the current between the phases. Currently there are no reasonable solutions to this mismatch. The droop function is used in a power supply to automatically lower the output voltage based on the output current. This provides more headroom in the case of load transients, and also removes the number of required output capacitors, thus lowering costs while still meeting the required voltage tolerances. The droop is set by the manufacturer of a processor and is based on a function of the regulator output current. Thus, the droop function accuracy is directly related to the current sensing accuracy. There are many ways to set the droop based on the measured current. For instance, one may limit the DC gain of the error amplifier in the current mode power supply, lower the reference by a ratio related to the overall current, increase the feedback based on the ratio of the overall current, or lower the error based on the ratio of overall current. All these topologies require accurate current sensing and accurate ratio settings at which the load current adjusts the output voltage. Historically, setting the droop accurately has also been a major problem due to inadequacies in current sensing and processor batch variations. Presently, the droop setting is fixed, thus once the system has been built, the droop rate cannot be changed without overly costly retrofits. Today, variations in processor power requirements vary from processor to processor, even those manufactured by the same manufacturer within the same batch. Because the droop setting is fixed, the power supply is unable to adapt to the processors power needs. Therefore, processors with power specifications beyond what the power supply can produce are wasted. This processor waste is very inefficient and costly. Another phenomenon affecting current sensing circuit is temperature. Most elements used in current sensing have positive temperature coefficients; the resistance of the circuit increases as the temperature increases. This variation results in erroneous measurements of the current over temperature variations causing further droop inaccuracies. The present invention provides a cost effective and automated solution to this and other shortcomings of current devices, systems, and methods. SUMMARY OF THE INVENTION One embodiment of the present invention may be a circuit comprising a regulator circuit and a calibration control circuit. The calibration control circuit includes a controller, an interface with nonvolatile memory, droop outputs, sense outputs, load voltage input, and temperature input. The calibration control circuit interfaces with the regulator circuit via the sense outputs, the droop outputs, and the load voltage input. The calibration control circuit interfaces with the temperature input to receive temperature data. The temperature data may be used by the calibration control circuit to adjust the sense outputs and the droop outputs. The calibration control circuit also interfaces with the temperature input and the load voltage input to calibrate the calibration data which may be stored in nonvolatile memory. In another embodiment of the present invention the regulator circuit may be a voltage mode regulator, a current mode regulator, a buck regulator, V-square, hysteretics, or any other power regulator. In another embodiment of the present invention the regulator circuit may be a multiphase regulator with any number of phases from one to infinity. The controller has at least one sense output for each phase of the multiphase regulator. In another embodiment of the present invention the calibration control circuit adjusts the sense outputs and the droop outputs according to data stored in the nonvolatile memory. In another embodiment of the present invention the nonvolatile memory stores regulator performance parameters and application specific power curve data. The nonvolatile memory may be either monolithic on non monolithic. The data stored in the nonvolatile memory for the droop outputs and sense outputs may be based on the load voltage input and the temperature input. In one embodiment the regulator circuit calibration data may be stored in a lookup table within the nonvolatile memory. In another embodiment of the present invention the droop outputs and the sense outputs include a digital to analog converter with registered input and an amplifier buffer. In another embodiment of the present invention the load voltage input may include a digital to analog converter with registered output. The temperature input may also include an analog to digital converter with registered output with both an amplifier and a temperature sensor. The temperature sensor may be internal or external to the circuit and may be an RTD, thermister, or a thermocouple. In another embodiment of the invention the load may include such processors as the Intel Pentium® series processors, the Intel Centrino® series processors, the Intel Express® series processors, the Intel Xenon® series processors, the Intel Celeron® series processors, the AMD Athlon® series processors, the AMD Duron® series processors, the AMD K6® series processors, the AMD Opteron® series processors, or the Power PC Sonnet® series processors. In another embodiment of the present invention the calibration control circuit may include a temperature output with a digital to analog converter with registered input and an amplifier buffer. This amplifier may be an adjustable amplifier that may be adjusted via the controller's temperature output. In another embodiment of the present invention the calibration control circuit may include an external interface to an external controller. This processor may monitor the load voltage input, and the temperature input. The processor may also control the sense outputs, the droop output, read data from the nonvolatile memory, and write to the nonvolatile memory. This process may be a computer, a state machine, or any other controller. In another embodiment of the present invention the calibration control circuit includes an error output. This output may include a digital to analog converter with registered input and an amplifier buffer. This output may interface with the regulator's error circuit In another embodiment of the present invention the regulator circuit includes a multiphase clock register, multiple phases, an adjustable droop amplifier, and an error circuit with an error amplifier. Each phase of the regulator may be powered by a phase of the multiphase clock generator and includes a set register, gate driver, output FETs, a current sense circuit, an adjustable sense amplifier, and a pulse width moderator. This multiphase clock register may have N phases, where N is an integer from 1 to infinity. Likewise the regulator may have N phases. A phase of the multiphase clock generator drives the set input of said set register. The set register drives the gate driver and the output FETs. These output FETs drive the load of the circuit. The current sense circuit measures the current of the output FETs and feeds back to the register via the adjustable sense amplifier and the pulse width modulator. The adjustable sense amplifier also feeds into the adjustable droop amplifier. The droop amplifier drives the error circuit. The error circuit drives each pulse width modulator on each phase. In another embodiment of the present invention the multiphase regulator includes an interface to an external controller. In another embodiment of the present invention the calibration control circuit interfaces with the multiphase regulator by adjusting the sense amplifiers in each phase via the sense outputs. The calibration control circuit may also adjust the droop amplifier via the droop output. Further, the calibration control circuit may monitor the load voltage output of the current sense circuit via the load voltage input. In another embodiment of the present invention the current sense circuit may be a RDSon of a power MOSFETs DCR of an inductor, sense series resistor, or a board trace. In another embodiment of the present invention the adjustable droop amplifier may be adjusted to compensate for regulator circuit variations. The sense amplifier may likewise be adjusted to compensate for regulator circuit variations. The present invention also embodies the methods of calibrating a calibration control circuit connected with a regulator supplying power to a load. This method begins with estimating the anticipated operation specifications of circuit's load. Output data may then be created based on this estimate and stored in nonvolatile memory. Both the regulator and the calibration control circuit may be placed in a circuit with a load. The load voltage input and temperature input of the calibration control circuit may be sampled. The sense outputs and the droop output may be adjusted until the input load voltage meets load operation specifications. The controller then creates data that relates the temperature with the sense outputs and temperature with the droop output and store the data in nonvolatile memory. In this embodiment any number of steps may be omitted or performed in any beneficial order. This process is repeated over a range of anticipated operating temperatures, across each phase, and with various anticipated loads. This method may also be monitored and controlled by an external controller and measurement equipment. The external controller may create the output data and write it to the external memory. In another embodiment of the present invention the calibration control circuit and the regulator may be included in one circuit: the control regulator. In order to minimize waste due to production variations in chip manufacture, this control regulator may be used to power a chip. The control regulator may be selected from a plurality of control regulators and the load may be a chip which also may be selected from a plurality of chips. The two may be placed in the same circuit such that the chip may be the load of the control regulator and the calibration allows each control regulator to power each chip according to the chip's unique power requirements. These chips may be processors, RAM, controllers, microprocessors, or any other chip whose power specifications vary with manufacture or temperature. This embodiment reduces chip waste by allowing the chip manufacturer to use chips with a broader range of operating specs because the control regulator may be calibrated to account for the matched chips unique power requirements. In another embodiment of the present invention a calibration control circuit may be implemented in a circuit with a regulator by first sampling temperature data from temperature input. The controller then. references the memory for stored calibration data that may be associated with the sampled temperature. Finally the controller sets the sense output and the droop output of the calibration control circuit according to the calibrated data. These steps may be continuously repeated at set intervals of time and across each phase. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic of one embodiment of the present invention showing two phases of a multiphase regulator with a calibration control circuit. FIG. 2 is a schematic of one embodiment of the present invention showing the calibration control circuit. DETAILED DESCRIPTION OF THE INVENTION It is to be understood that the present invention is not limited to the particular methodology, compounds, materials, manufacturing techniques, uses, and applications, described herein, as these may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. It must be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to “an element” is a reference to one or more elements and includes equivalents thereof known to those skilled in the art. Similarly, for another example, a reference to “a step” or “a means” is a reference to one or more steps or means and may include sub-steps and subservient means. All conjunctions used are to be understood in the most inclusive sense possible. Thus, the word “or” should be understood as having the definition of a logical “or” rather than that of a logical “exclusive or” unless the context clearly necessitates otherwise. Structures described herein are to be understood also to refer to functional equivalents of such structures. Language that may be construed to express approximation should be so understood unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Preferred methods, techniques, devices, and materials are described, although any methods, techniques, devices, or materials similar or equivalent to those described herein may be used in the practice or testing of the present invention. Structures described herein are to be understood also to refer to functional equivalents of such structures. All references cited herein are incorporated by reference herein in their entirety. This invention is a new and innovative active current sharing application that can result in near perfect current match across phases of a multiphase regulator. This invention also provides accurate temperature-independent droop settings that can be programmed for specific and changing applications in the field. The disclosed circuit is digitally calibrated to compensate for the inaccuracies of the current sensing elements. This calibration data is preferably stored in nonvolatile memory, where it can be reused, modified, and restored throughout the life of the power supply. Thus, at power up, the current sensing mechanism is adjusted by the calibration parameters such that the overall gain of the sensing mechanism in all phases may be matched, and the total current across all phases is shared equally regardless of the temperature or the load. This invention provides near equivalent power to a load across all phases of a multiphase power supply. By calibrating the droop and sense settings over various temperatures for a specific load the power supply compensates for inaccuracies in the circuit. This calibration data may be storied in nonvolatile memory. Providing such equivalent power across phases enhances load performance. This calibration also provides the power supply with the necessary settings to meet the unique specifications of the load. This load may be any type of circuit. Typically the load may be an integrated processor, memory, or any other integrated circuit. Such processors may include the Intel Pentium® series processors, the Intel Centrino® series processors, the Intel Express® series processors, the Intel Xenon® series processors, the Intel Celeron® series processors, the AMD Athlon® series processors, the AMD Duron® series processors, the AMD K6® series processors, the AMD Opteron® series processors, or the Power PC Sonnet® series processors. The load may also be any type of memory, flash, integrated circuit, or any complete system application This invention may further power a circuit that requires near constant and consistent power over time, variations in temperature, and across phases. This invention also provides methods of using the calibration circuits of the present invention. The regulator may be placed in a circuit in such away that it powers a load. This load may be any type of circuit requiring application specific power. Through an external interface connected to a programmed processor or state machine, the regulator may be calibrated to meet the specific load requirements of the load. The load voltage and the temperature may be monitored while the droop and sense settings may be adjusted until the load voltage meets the load's specification. Data may be created corresponding to the temperature and the droop and sense settings. This data may then be stored in memory. The process may be repeated over an anticipated temperature range. This process may be performed during the testing and calibration phase of the entire circuit. Providing such consistency across the phases of the regulator and allowing the regulator to meet load specific specifications allows a circuit manufacturer to use loads with a greater range of power needs. Thus, the number of loads that may be wasted because the regulator is unable to meet their needs is minimized. Further, load performance is enhanced because the calibration circuit provides settings based on temperature variations. The present invention also may include a circuit comprising a regulator circuit and a calibration control circuit. The calibration control circuit may include a controller, an interface with nonvolatile memory, droop outputs, sense outputs, load voltage input, and a temperature input. The calibration control circuit interfaces with the regulator circuit via the sense outputs, the droop outputs, and the load voltage input. The calibration control circuit interfaces with said temperature input to receive temperature data. The temperature data may be used by the calibration control circuit to adjust the sense outputs and the droop outputs. The calibration control circuit also interfaces with the temperature input and the load voltage input to calibrate the calibration data which may be stored in nonvolatile memory. The regulator circuits of this invention may include a voltage mode regulator, a current mode regulator, a buck regulator, V-square, hysteretics, or any other power regulator. The regulator circuit may also be a multiphase regulator with any number of phases from one to infinity. The controller preferably has at least one sense output for each phase of a multiphase regulator. The calibration control circuits of this invention may adjust the sense outputs and the droop outputs according to data stored in the nonvolatile memory. The nonvolatile memory of the present invention may store regulator performance parameters and application specific power curve data. The nonvolatile memory may be either monolithic on non monolithic. The data stored in the nonvolatile memory for the droop outputs and the outputs may be based on the load voltage input and the temperature input. In one embodiment the regulator circuit calibration data may be stored in a lookup table within the nonvolatile memory. The outputs of the present invention may include a digital to analog converter with registered input and an amplifier buffer, while the inputs may include a digital to analog converter with registered output. The temperature input may further include an amplifier and a temperature sensor. The temperature sensor may be internal or external to the circuit and may be an RTD, thermister, or a thermocouple. The calibration control circuits of the present invention may include a temperature output. This output may include a digital to analog converter with registered input and an amplifier buffer. This amplifier may be an adjustable amplifier that may be adjusted via the controller's temperature output. The circuits of the present invention may include an external interface to an external controller. This processor may monitor the load voltage input, and the temperature input. The processor may also control the sense outputs, the droop output, read data from the nonvolatile memory, and write to the nonvolatile memory. This processor may be a computer, a state machine, or any other controller. The calibration control circuits may include an error output. This output may include a digital to analog converter with registered input and an amplifier buffer. This output may interface with the regulator's error circuit The regulator circuits may include a multiphase clock register, multiple phases, an adjustable droop amplifier, and an error circuit with an error amplifier. Each phase of the regulator may be powered by a single phase of the multiphase clock generator and includes a set register, gate driver, output FETs, a current sense circuit, an adjustable sense amplifier, and a pulse width moderator. This multiphase clock register may have N phases, where N is an integer from 1 to infinity. Likewise the regulator may have N phases. A phase of the multiphase clock generator may drive the set input of said set register. The set register drives the gate driver and the output FETs. These output FETs drive the load of the circuit. The current sense circuit measures the current of the output FETs and feeds back to the register via the adjustable sense amplifier and the pulse width modulator. The adjustable sense amplifier also feeds into the adjustable droop amplifier. The droop amplifier drives the error circuit. The error circuit drives each pulse width modulator on each phase. The multiphase regulator may include an interface to an external controller. The calibration control circuits of the present invention may interface with the multiphase regulator by adjusting the sense amplifiers in each phase via the sense outputs. The calibration control circuit may also adjust the droop amplifier via the droop output. Further, the calibration control circuit may monitor the load voltage output of the current sense circuit via the load voltage input. The calibration control circuit may adjust the error amplifier. The current sense circuit may include the RDSon of a power MOSFETs DCR of an inductor, sense series resistor, or a board trace. The adjustable droop amplifier may be adjusted to compensate for regulator circuit variations. The sense amplifier may likewise be adjusted to compensate for regulator circuit variations. This invention includes methods of calibrating a calibration control circuit connected with a regulator supplying power to a load. These methods may begin with estimating the anticipated operation specifications of circuit's load, creating a set of output data based on this estimate, and taking the output data and storing it in nonvolatile memory. Both the regulator and the calibration control circuit may be placed in a circuit with a load. The methods of the present invention may then sample the load voltage input at the interface between the regulator and the load and sample the temperature input of the calibration control circuit. The sense outputs and the droop output then may be adjusted until the input load voltage meets load operation specifications. The controller then may create data that relates the temperature with the sense outputs and temperature with the droop output and store the data in nonvolatile memory. In the methods of the present invention any number of steps may be omitted or performed in any beneficial order. The methods may the be repeated over a range of anticipated operating temperatures, across each phase, and with various anticipated loads. The methods also may be monitored and controlled by an external controller and measurement equipment. The external controller may create the output data and write it to the nonvolatile memory. The calibration control circuit and the regulator may be included in one circuit: the control regulator. In order to minimize waste due to production variations in chip manufacture, this control regulator may be used to power a chip. The control regulator may be selected from a plurality of control regulators and the load may be a chip which also may be selected from a plurality of chips. The two may be placed in the same circuit such that the chip may be the load of the control regulator and the calibration allows each control regulator to power each chip according to the chip's unique power requirements. These chips may be processors, RAM, controllers, microprocessors, or any other chip whose power specifications vary with manufacture or temperature. This embodiment reduces chip waste by allowing the chip manufacturer to use chips with a broader range of operating specs because the control regulator may be calibrated to account for the matched chips unique power requirements. In yet another application of the present invention the load may be any complete system application consisting of multiple components. The load of the invention may include such processors as the Intel Pentium® series processors, the Intel Centrino® series processors, the Intel Express® series processors, the Intel Xenon® series processors, the Intel Celeron® series processors, the AMD Athlon® series processors, the AMD Duron® series processors, the AMD K6® series processors, the AMD Opteron® series processors, the Power PC Sonnet® series processors, or any integrated circuit processor may also be included. The load may also be any type of memory, flash, integrated circuit, or any complete system application. The calibration control circuit may be implemented in a circuit with a regulator by first sampling temperature data from temperature input. The controller then references the memory for stored calibration data that may be associated with the sampled temperature. Finally the controller may set the sense output and the droop output of the calibration control circuit according to the calibrated data. These steps may be continuously repeated at set intervals of time, repeated across each phase, and in any beneficial and practical order. Referring to the figures, FIG. 1 is a schematic of one embodiment of the present invention showing two phases of a multiphase regulator connected with a calibration control circuit 190. This multiphase regulator may be a multiphase regulator of any number of phases from one to infinity. A multiphase clock generator 100 on each phase drives the set input of the phase control set register 110. This register in turn drives gate driver 120 and the output FET 130 to generate the source power for the specific phase output. A current sense circuit 140 may be placed between the output FET 130 and the load 165. This current sense circuit may be implemented by measuring the current across the sense resistors, an RDS on the output FET driver, the current across the inductor of a DCR circuit, or the current across the resistance of a board trace. No matter the implementation of the current sense circuit, the current sense circuit feeds back to the regulator circuit through the adjustable sense amplifier 150 and a pulse width modulator 160. The adjustable sense amplifier may be adjusted via the calibration control circuit 190. The adjustable sense amplifier 150 controls the variances in the current sensing circuit. By adjusting the feedback gain of the adjustable sense amplifier 150, variations in the current sense circuit of each phase can be balanced to equalize the load seen by each phase of a multi-phase regulator. The output of the adjustable sense amplifier 150 drives the current sense input of the pulse width modulator (PWM) 160 to generate the proper pulse width signal to the power output FET 130 to regulate the output power. The adjustable sense amplifier 150 also drives the shared summing input port to the adjustable droop amplifier 180. This adjustable droop amplifier 180 may be used to adjust the droop loss across the current sense circuit 140. The adjustment of the droop amplifier 180 may be used to drive an error circuit. The adjusted voltage driver circuit may be compared against the reference voltage at the error amplifier 175 to generate the error voltage value for the pulse width modulators 160. Adjusting the droop amplifier 180 may be equivalent to adjusting the reference voltage. The load voltage 165 may be monitored via the calibration control circuit 190. The output of the error amplifier 175 drives one port of each pulse width modulator 160 to compensate for the droop loss. The output of an individual pulse width modulator 160 drives its associated phase control set register 110 to control the output drive FET 130. The current sense circuit 140 also varies over operating. In one embodiment of the present invention a temperature sensor 210, in line with an adjustable temperature amplifier 200, and interfacing with the calibration control circuit 190 may be used to monitor the variations in the operating temperature. This temperature sensor may be internal or external to either the regulator circuit or the calibration control circuit 190. The data received from the temperature sensor 210 may be used to adjust the droop amplifier 180 and the sense amplifiers 150 to regulate the output power over variations in temperature. The calibration control circuit 190 in FIG. 1 is shown in more detail in FIG. 2. FIG. 2 shows one embodiment of the calibration control circuit. The calibration control circuit controls the adjustments to the droop amplifier via the droop output 550 and the sense amplifiers via sense outputs 530. The main component of the calibration control circuit is the controller 500. The controller 500 may be a state machine, a processor or any other logic device. The controller 500 adjusts the sense amplifiers of the regulator circuit via sense outputs 530. The controller 500 has an output for each phase of a multiphase regulator. These sense outputs 530 in one embodiment interface with the adjustable sense amplifiers via a digital to analog converter with registered input 510, and an amplifier 505. Likewise the droop output 550 from the controller 500 in one embodiment interfaces with the adjustable droop amplifier via a digital to analog converter with registered input 600 and an amplifier 640. Further, the temperature output 560 from the controller 500 in one embodiment interfaces with the adjustable temperature amplifier via a digital to analog converter with registered input 610 and an amplifier 650. The controller samples load voltage input 570 from the regulator circuit in one embodiment via an analog to digital converter with registered output 670. Likewise, the controller samples temperature input 580 from the temperature sensor in one embodiment via an analog to digital converter with registered output 680. The controller 500 interfaces with nonvolatile memory 590 that holds temperature dependent settings of the droop output and sense outputs. This nonvolatile memory 590 may be located on the calibration control circuit or may be located elsewhere. The controller 500 also interfaces with an external controller that may control the adjustments directly, read the status values of the sample inputs for temperature and load voltage, and to read and write the nonvolatile memory contents. It will be apparent to those skilled in the art that various modifications and variations can be made in the circuits or methods of the present invention without departing from the scope and spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only of the present invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Multi-phase voltage regulators are commonly used over single-phase regulators because they produce higher current output, faster transient responses, and more efficient applications in microprocessor power supplies. Due to discrete components and power device mismatches, the load current is not always equally shared among all the phases of multi-phase regulators causing inadequate operation and excessive heat in the power devices of one or more phases of a multi-phase power supply. To overcome this problem, active current sharing may be utilized to force current equalization among all phases. This requires a current sensing circuit. Since sense resistors are both inefficient and expensive, other resistive elements such as RDSon of the power MOSFETs, DCR of the inductor, and board traces are used to measure the source current for each phase of the power supply. These elements have a high degree of variation from one to another over changing environmental conditions and over production lot variations. Historically, using these elements to sense current causes a mismatch in the current between the phases. Currently there are no reasonable solutions to this mismatch. The droop function is used in a power supply to automatically lower the output voltage based on the output current. This provides more headroom in the case of load transients, and also removes the number of required output capacitors, thus lowering costs while still meeting the required voltage tolerances. The droop is set by the manufacturer of a processor and is based on a function of the regulator output current. Thus, the droop function accuracy is directly related to the current sensing accuracy. There are many ways to set the droop based on the measured current. For instance, one may limit the DC gain of the error amplifier in the current mode power supply, lower the reference by a ratio related to the overall current, increase the feedback based on the ratio of the overall current, or lower the error based on the ratio of overall current. All these topologies require accurate current sensing and accurate ratio settings at which the load current adjusts the output voltage. Historically, setting the droop accurately has also been a major problem due to inadequacies in current sensing and processor batch variations. Presently, the droop setting is fixed, thus once the system has been built, the droop rate cannot be changed without overly costly retrofits. Today, variations in processor power requirements vary from processor to processor, even those manufactured by the same manufacturer within the same batch. Because the droop setting is fixed, the power supply is unable to adapt to the processors power needs. Therefore, processors with power specifications beyond what the power supply can produce are wasted. This processor waste is very inefficient and costly. Another phenomenon affecting current sensing circuit is temperature. Most elements used in current sensing have positive temperature coefficients; the resistance of the circuit increases as the temperature increases. This variation results in erroneous measurements of the current over temperature variations causing further droop inaccuracies. The present invention provides a cost effective and automated solution to this and other shortcomings of current devices, systems, and methods.
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<SOH> SUMMARY OF THE INVENTION <EOH>One embodiment of the present invention may be a circuit comprising a regulator circuit and a calibration control circuit. The calibration control circuit includes a controller, an interface with nonvolatile memory, droop outputs, sense outputs, load voltage input, and temperature input. The calibration control circuit interfaces with the regulator circuit via the sense outputs, the droop outputs, and the load voltage input. The calibration control circuit interfaces with the temperature input to receive temperature data. The temperature data may be used by the calibration control circuit to adjust the sense outputs and the droop outputs. The calibration control circuit also interfaces with the temperature input and the load voltage input to calibrate the calibration data which may be stored in nonvolatile memory. In another embodiment of the present invention the regulator circuit may be a voltage mode regulator, a current mode regulator, a buck regulator, V-square, hysteretics, or any other power regulator. In another embodiment of the present invention the regulator circuit may be a multiphase regulator with any number of phases from one to infinity. The controller has at least one sense output for each phase of the multiphase regulator. In another embodiment of the present invention the calibration control circuit adjusts the sense outputs and the droop outputs according to data stored in the nonvolatile memory. In another embodiment of the present invention the nonvolatile memory stores regulator performance parameters and application specific power curve data. The nonvolatile memory may be either monolithic on non monolithic. The data stored in the nonvolatile memory for the droop outputs and sense outputs may be based on the load voltage input and the temperature input. In one embodiment the regulator circuit calibration data may be stored in a lookup table within the nonvolatile memory. In another embodiment of the present invention the droop outputs and the sense outputs include a digital to analog converter with registered input and an amplifier buffer. In another embodiment of the present invention the load voltage input may include a digital to analog converter with registered output. The temperature input may also include an analog to digital converter with registered output with both an amplifier and a temperature sensor. The temperature sensor may be internal or external to the circuit and may be an RTD, thermister, or a thermocouple. In another embodiment of the invention the load may include such processors as the Intel Pentium® series processors, the Intel Centrino® series processors, the Intel Express® series processors, the Intel Xenon® series processors, the Intel Celeron® series processors, the AMD Athlon® series processors, the AMD Duron® series processors, the AMD K6® series processors, the AMD Opteron® series processors, or the Power PC Sonnet® series processors. In another embodiment of the present invention the calibration control circuit may include a temperature output with a digital to analog converter with registered input and an amplifier buffer. This amplifier may be an adjustable amplifier that may be adjusted via the controller's temperature output. In another embodiment of the present invention the calibration control circuit may include an external interface to an external controller. This processor may monitor the load voltage input, and the temperature input. The processor may also control the sense outputs, the droop output, read data from the nonvolatile memory, and write to the nonvolatile memory. This process may be a computer, a state machine, or any other controller. In another embodiment of the present invention the calibration control circuit includes an error output. This output may include a digital to analog converter with registered input and an amplifier buffer. This output may interface with the regulator's error circuit In another embodiment of the present invention the regulator circuit includes a multiphase clock register, multiple phases, an adjustable droop amplifier, and an error circuit with an error amplifier. Each phase of the regulator may be powered by a phase of the multiphase clock generator and includes a set register, gate driver, output FETs, a current sense circuit, an adjustable sense amplifier, and a pulse width moderator. This multiphase clock register may have N phases, where N is an integer from 1 to infinity. Likewise the regulator may have N phases. A phase of the multiphase clock generator drives the set input of said set register. The set register drives the gate driver and the output FETs. These output FETs drive the load of the circuit. The current sense circuit measures the current of the output FETs and feeds back to the register via the adjustable sense amplifier and the pulse width modulator. The adjustable sense amplifier also feeds into the adjustable droop amplifier. The droop amplifier drives the error circuit. The error circuit drives each pulse width modulator on each phase. In another embodiment of the present invention the multiphase regulator includes an interface to an external controller. In another embodiment of the present invention the calibration control circuit interfaces with the multiphase regulator by adjusting the sense amplifiers in each phase via the sense outputs. The calibration control circuit may also adjust the droop amplifier via the droop output. Further, the calibration control circuit may monitor the load voltage output of the current sense circuit via the load voltage input. In another embodiment of the present invention the current sense circuit may be a RDSon of a power MOSFETs DCR of an inductor, sense series resistor, or a board trace. In another embodiment of the present invention the adjustable droop amplifier may be adjusted to compensate for regulator circuit variations. The sense amplifier may likewise be adjusted to compensate for regulator circuit variations. The present invention also embodies the methods of calibrating a calibration control circuit connected with a regulator supplying power to a load. This method begins with estimating the anticipated operation specifications of circuit's load. Output data may then be created based on this estimate and stored in nonvolatile memory. Both the regulator and the calibration control circuit may be placed in a circuit with a load. The load voltage input and temperature input of the calibration control circuit may be sampled. The sense outputs and the droop output may be adjusted until the input load voltage meets load operation specifications. The controller then creates data that relates the temperature with the sense outputs and temperature with the droop output and store the data in nonvolatile memory. In this embodiment any number of steps may be omitted or performed in any beneficial order. This process is repeated over a range of anticipated operating temperatures, across each phase, and with various anticipated loads. This method may also be monitored and controlled by an external controller and measurement equipment. The external controller may create the output data and write it to the external memory. In another embodiment of the present invention the calibration control circuit and the regulator may be included in one circuit: the control regulator. In order to minimize waste due to production variations in chip manufacture, this control regulator may be used to power a chip. The control regulator may be selected from a plurality of control regulators and the load may be a chip which also may be selected from a plurality of chips. The two may be placed in the same circuit such that the chip may be the load of the control regulator and the calibration allows each control regulator to power each chip according to the chip's unique power requirements. These chips may be processors, RAM, controllers, microprocessors, or any other chip whose power specifications vary with manufacture or temperature. This embodiment reduces chip waste by allowing the chip manufacturer to use chips with a broader range of operating specs because the control regulator may be calibrated to account for the matched chips unique power requirements. In another embodiment of the present invention a calibration control circuit may be implemented in a circuit with a regulator by first sampling temperature data from temperature input. The controller then. references the memory for stored calibration data that may be associated with the sampled temperature. Finally the controller sets the sense output and the droop output of the calibration control circuit according to the calibrated data. These steps may be continuously repeated at set intervals of time and across each phase.
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20040629
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20060411
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20050203
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72121.0
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TSAI, CAROL S W
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PROGRAMMABLE CALIBRATION CIRCUIT FOR POWER SUPPLY CURRENT SENSING AND DROOP LOSS COMPENSATION
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SMALL
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ACCEPTED
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10,878,623
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ACCEPTED
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Nanoparticulate megestrol formulations
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The present invention is directed to nanoparticulate compositions comprising megestrol. The megestrol particles of the composition have an effective average particle size of less than about 2000 nm.
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1. A megestrol nanoparticulate composition comprising: (a) particles of megestrol, megestrol acetate, or a salt thereof; and (b) associated with the surface thereof at least one surface stabilizer, wherein the megestrol particles have an effective average particle size of less than about 2000 nm. 2. The composition of claim 1, wherein the megestrol is selected from the group consisting of a crystalline phase, an amorphous phase, a semi-crystalline phase, a semi-amorphous phase, and mixtures thereof. 3. The composition of claim 1, wherein the effective average particle size of the nanoparticulate megestrol particles is selected from the group consisting of less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 100 nm, less than about 75 nm, and less than about 50 nm. 4. The composition of claim 1, wherein the composition is formulated for administration selected from the group consisting of oral, pulmonary, rectal, opthalmic, colonic, parenteral, intracisternal, intravaginal, intraperitoneal, local, buccal, nasal, and topical administration. 5. The composition of claim 1, wherein the composition is formulated into a dosage form selected from the group consisting of liquid dispersions, gels, aerosols, ointments, creams, controlled release formulations, fast melt formulations, lyophilized formulations, tablets, capsules, delayed release formulations, extended release formulations, pulsatile release formulations, and mixed immediate release and controlled release formulations. 6. The composition of claim 1, wherein the composition further comprises one or more pharmaceutically acceptable excipients, carriers, or a combination thereof. 7. The composition of claim 1, wherein the megestrol is present in an amount selected from the group consisting of from about 99.5% to about 0.001%, from about 95% to about 0.1%, and from about 90% to about 0.5%, by weight, based on the total combined weight of the megestrol and at least one surface stabilizer, not including other excipients. 8. The composition of claim 1, wherein the at least one surface stabilizer is present in an amount selected from the group consisting of from about 0.5% to about 99.999%, from about 5.0% to about 95%, and from about 10% to about 99.5%, by weight, based on the total combined dry weight of the megestrol and at least one surface stabilizer, not including other excipients. 9. The composition of claim 1, comprising at least two surface stabilizers, including a primary and a secondary surface stabilizer. 10. The composition of claim 9, wherein at least one surface stabilizer is selected from the group consisting of hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, and random copolymers of vinyl acetate and vinyl pyrrolidone. 11. The composition of claim 9, wherein at least one surface stabilizer is selected from the group consisting of sodium lauryl sulfate and dioctyl sodium sulfosuccinate. 12. The composition of claim 9, wherein at least one secondary surface stabilizer is present in an amount selected from the group consisting of from about 0.01% to about 99%, from about 0.1% to about 95%, and from about 1% to about 90%, by weight, based on the total combined dry weight of the megestrol, at least one primary surface stabilizer, and at least one secondary surface stabilizer, not including other excipients. 13. The composition of claim 1, wherein the surface stabilizer is selected from the group consisting of an anionic surface stabilizer, a cationic surface stabilizer, an ionic surface stabilizer, and a zwitterionic surface stabilizer. 14. The composition of claim 13, wherein the at least one surface stabilizer is selected from the group consisting of cetyl pyridinium chloride, gelatin, casein, phosphatides, dextran, glycerol, gum acacia, cholesterol, tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glycerol monostearate, cetostearyl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, polyethylene glycols, dodecyl trimethyl ammonium bromide, polyoxyethylene stearates, colloidal silicon dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, hydroxypropyl celluloses, hydroxypropyl methylcellulose, carboxymethylcellulose sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylmethyl-cellulose phthalate, noncrystalline cellulose, magnesium aluminum silicate, triethanolamine, polyvinyl alcohol, polyvinylpyrrolidone, 4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide and formaldehyde, poloxamers; poloxamines, a charged phospholipid, dioctylsulfosuccinate, dialkylesters of sodium sulfosuccinic acid, sodium lauryl sulfate, alkyl aryl polyether sulfonates, mixtures of sucrose stearate and sucrose distearate, p-isononylphenoxypoly-(glycidol), decanoyl-N-methylglucamide; n-decyl β-D-glucopyranoside; n-decyl β-D-maltopyranoside; n-dodecyl β-D-glucopyranoside; n-dodecyl β-D-maltoside; heptanoyl-N-methylglucamide; n-heptyl-β-D-glucopyranoside; n-heptyl β-D-thioglucoside; n-hexyl β-D-glucopyranoside; nonanoyl-N-methylglucamide; n-noyl β-D-glucopyranoside; octanoyl-N-methylglucamide; n-octyl-β-D-glucopyranoside; octyl β-D-thioglucopyranoside; lysozyme, PEG-phospholipid, PEG-cholesterol, PEG-cholesterol derivative, PEG-vitamin A, PEG-vitamin E, and random copolymers of vinyl acetate and vinyl pyrrolidone. 15. The composition of claim 13, wherein the at least one cationic surface stabilizer is selected from the group consisting of a polymer, a biopolymer, a polysaccharide, a cellulosic, an alginate, a nonpolymeric compound, and a phospholipid. 16. The composition of claim 13, wherein the surface stabilizer is selected from the group consisting of polymethylmethacrylate trimethylammonium bromide, polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate, hexadecyltrimethyl ammonium bromide, cationic lipids, sulfonium compounds, phosphonium compounds, quarternary ammonium compounds, benzyl-di(2-chloroethyl)ethylammonium bromide, coconut trimethyl ammonium chloride, coconut trimethyl ammonium bromide, coconut methyl dihydroxyethyl ammonium chloride, coconut methyl dihydroxyethyl ammonium bromide, decyl triethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride bromide, C12-15dimethyl hydroxyethyl ammonium chloride, C12-15dimethyl hydroxyethyl ammonium chloride bromide, coconut dimethyl hydroxyethyl ammonium chloride, coconut dimethyl hydroxyethyl ammonium bromide, myristyl trimethyl ammonium methyl sulphate, lauryl dimethyl benzyl ammonium chloride, lauryl dimethyl benzyl ammonium bromide, lauryl dimethyl (ethenoxy)4 ammonium chloride, lauryl dimethyl (ethenoxy)4 ammonium bromide, N-alkyl (C12-18)dimethylbenzyl ammonium chloride, N-alkyl (C14-18)dimethyl-benzyl ammonium chloride, N-tetradecylidmethylbenzyl ammonium chloride monohydrate, dimethyl didecyl ammonium chloride, N-alkyl and (C12-14) dimethyl 1-napthylmethyl ammonium chloride, trimethylammonium halide, alkyl-trimethylammonium salts, dialkyl-dimethylammonium salts, lauryl trimethyl ammonium chloride, ethoxylated alkyamidoalkyldialkylammonium salt, an ethoxylated trialkyl ammonium salt, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium, chloride monohydrate, N-alkyl(C12-14) dimethyl 1-naphthylmethyl ammonium chloride, dodecyldimethylbenzyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, C12 trimethyl ammonium bromides, C15 trimethyl ammonium bromides, C17 trimethyl ammonium bromides, dodecylbenzyl triethyl ammonium chloride, poly-diallyldimethylammonium chloride (DADMAC), dimethyl ammonium chlorides, alkyldimethylammonium halogenides, tricetyl methyl ammonium chloride, decyltrimethylammonium bromide, dodecyltriethylammonium bromide, tetradecyltrimethylammonium bromide, methyl trioctylammonium chloride, POLYQUAT 10™, tetrabutylammonium bromide, benzyl trimethylammonium bromide, choline esters, benzalkonium chloride, stearalkonium chloride compounds, cetyl pyridinium bromide, cetyl pyridinium chloride, halide salts of quaternized polyoxyethylalkylamines, MIRAPOL™, ALKAQUAT™, alkyl pyridinium salts; amines, amine salts, amine oxides, imide azolinium salts, protonated quaternary acrylamides, methylated quaternary polymers, lysozyme, and cationic guar. 17. The composition of claim 15 or 16, wherein the composition is bioadhesive. 18. The composition of claim 1, wherein the amount of megestrol is selected from the group consisting of 3 percent by weight, 5 percent by weight, and 9 percent by weight. 19. The composition of claim 18, additionally comprising hydroxypropyl methyl cellulose and dioctyl sodium sulfosuccinate as surface stabilizers. 20. The composition of claim 1, further comprising a megestrol composition having an effective average particle size of greater than about 2 microns. 21. The composition of claim 1, additionally comprising at least one additional nanoparticulate megestrol composition having an effective average particle size of less than about 2 microns, wherein said additional nanoparticulate megestrol composition has an effective average particle size which is different than the effective average particle size of the nanoparticulate megestrol composition of claim 1. 22. The composition of claim 1, additionally comprising at least one non-megestrol active agent. 23. The composition of claim 22, wherein said active agent is selected from the group consisting of amino acids, proteins, peptides, nucleotides, anti-obesity drugs, nutraceuticals, dietary supplements, central nervous symptom stimulants, carotenoids, corticosteroids, elastase inhibitors, anti-fungals, alkylxanthine, oncology therapies, anti-emetics, analgesics, opioids, antipyretics, cardiovascular agents, anti-inflammatory agents, anthelmintics, anti-arrhythmic agents, antibiotics, anticoagulants, antidepressants, antidiabetic agents, antiepileptics, antihistamines, antihypertensive agents, antimuscarinic agents, antimycobacterial agents, antineoplastic agents, immunosuppressants, antithyroid agents, antiviral agents, anxiolytics, sedatives, astringents, alpha-adrenergic receptor blocking agents, beta-adrenoceptor blocking agents, blood products, blood substitutes, cardiac inotropic agents, contrast media, corticosteroids, cough suppressants, diagnostic agents, diagnostic imaging agents, diuretics, dopaminergics, haemostatics, immunological agents, lipid regulating agents, muscle relaxants, parasympathomimetics, parathyroid calcitonin and biphosphonates, prostaglandins, radio-pharmaceuticals, sex hormones, anti-allergic agents, stimulants, anoretics, sympathomimetics, thyroid agents, vasodilators, vasomodulator, xanthines, Mu receptor antagonists, Kappa receptor antagonists, non-narcotic analgesics, monoamine uptake inhibitors, adenosine regulating agents, cannabinoid derivatives, Substance P antagonists, neurokinin-1 receptor antagonists, and sodium channel blockers. 24. The composition of claim 23, wherein said nutraceutical is selected from the group consisting of lutein, folic acid, fatty acids, fruit extracts, vegetable extracts, vitamin supplements, mineral supplements, phosphatidylserine, lipoic acid, melatonin, glucosamine/chondroitin, Aloe Vera, Guggul, glutamine, amino acids, green tea, lycopene, whole foods, food additives, herbs, phytonutrients, antioxidants, flavonoid constituents of fruits, evening primrose oil, flax seeds, fish oils, marine animal oils, and probiotics. 25. The composition of any of claims 22, 23, or 24, wherein at least one non-megestrol active agent has an effective average particle size of less than about 2 microns. 26. The composition of any of any of claims 22, 23, or 24, wherein at least one non-megestrol active agent has an effective average particle size of greater than about 2 microns. 27. The composition of claim 1, wherein upon administration the composition redisperses such that the megestrol particles have a particle size selected from the group consisting of less than about 2 microns, less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 150 nm, less than about 100 nm, less than about 75 nm, and less than about 50 nm. 28. The composition of claim 1, wherein the composition redisperses in a biorelevant media such that the megestrol particles have a particle size selected from the group consisting of less than about 2 microns, less than about 1900 nm, less than about 1800 mm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 150 nm, less than about 100 nm, less than about 75 nm, and less than about 50 nm. 29. The composition of claim 1, wherein the composition does not produce significantly different absorption levels when administered under fed as compared to fasting conditions. 30. The composition of claim 1, wherein the difference in absorption of the nanoparticulate megestrol composition, when administered in the fed versus the fasted state, is selected from the group consisting of less than about 100%, less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 35%, less than about 30%, less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than about 5%, and less than about 3%. 31. The composition of claim 1, wherein the composition does not produce significantly different rates of absorption (Tmax) when administered under fed as compared to fasting conditions. 32. The composition of claim 1, wherein the difference in the Tmax for the nanoparticulate megestrol composition, when administered in the fed versus the fasted state, is less than about 100%, less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 20%, less than about 15%, less than about 10%, less than about 5%, and less than about 3%. 33. The composition of claim 1, wherein upon administration the Tmax is less than that of a standard commercial non-nanoparticulate composition of megestrol, administered at the same dosage. 34. The composition of claim 1, wherein following administration the composition has a Tmax selected from the group consisting of less than about 5 hours, less than about 4.5 hours, less than about 4 hours, less than about 3.5 hours, less than about 3 hours, less than about 2.75 hours, less than about 2.5 hours, less than about 2.25 hours, less than about 2 hours, less than about 1.75 hours, less than about 1.5 hours, less than about 1.25 hours, less than about 1.0 hours, less than about 50 minutes, less than about 40 minutes, less than about 30 minutes, less than about 25 minutes, less than about 20 minutes, less than about 15 minutes, and less than about 10 minutes. 35. The composition of claim 34, wherein the composition exhibits a Tmax of less than 5 hours after administration. 36. The composition of claim 34, wherein the composition exhibits a Tmax not greater than about 3 hours after administration. 37. The composition of claim 1, wherein in comparative pharmacokinetic testing with a standard commercial non-nanoparticulate composition of megestrol, administered at the same dosage, the nanoparticulate composition exhibits a Tmax selected from the group consisting of less than about 100%, less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 25%, less than about 20%, less than about 15%, and less than about 10% of the Tmax exhibited by the non-nanoparticulate composition of megestrol. 38. The composition of claim 1, wherein in comparative pharmacokinetic testing with a standard commercial formulation of megestrol, the composition exhibits a Tmax not greater than about 50% of the Tmax exhibited by the standard commercial megestrol formulation. 39. The composition of claim 1, wherein in comparative pharmacokinetic testing with a standard commercial formulation of megestrol, the composition exhibits a Tmax not greater than about 33% of the Tmax exhibited by the standard commercial megestrol formulation. 40. The composition of claim 1, wherein in comparative pharmacokinetic testing with a standard commercial formulation of megestrol, the composition exhibits a Tmax not greater than about 25% of the Tmax exhibited by the standard commercial megestrol formulation. 41. The composition of claim 1, wherein upon administration the Cmax of the composition is greater than the Cmax of a standard commercial non-nanoparticulate composition of megestrol, administered at the same dosage. 42. The composition of claim 1, wherein in comparative pharmacokinetic testing with a standard commercial non-nanoparticulate composition of megestrol, administered at the same dosage, the nanoparticulate composition exhibits a Cmax selected from the group consisting of greater than about 5%, greater than about 10%, greater than about 15%, greater than about 20%, greater than about 30%, greater than about 40%, greater than about 50%, greater than about 60%, greater than about 70%, greater than about 80%, greater than about 90%, greater than about 100%, greater than about 110%, greater than about 120%, greater than about 130%, greater than about 140%, greater than about 150%, greater than about 200%, greater than about 500% and greater than about 800% than the Cmax exhibited by the non-nanoparticulate composition of megestrol. 43. The composition of claim 1, wherein the therapeutically effective amount of the megestrol is selected from the group consisting of ⅙, ⅕, ¼, ⅓rd, or ½ of the therapeutically effective amount of a standard commercial megestrol formulation. 44. The composition of claim 1, wherein the difference in absorption when the composition is administered in the fed versus the fasted state is selected from the group consisting of less than about 35%, less than about 30%, less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than about 5%, and less than about 3%. 45. The composition of claim 1, wherein the composition is in a liquid oral dosage form, and the viscosity of the composition is selected from the group consisting of less than about {fraction (1/200)}, less than about {fraction (1/175)}, less than about {fraction (1/150)}, less than about {fraction (1/125)}, less than about {fraction (1/100)}, less than about {fraction (1/50)}, and less than about {fraction (1/25)} of the viscosity of a standard commercial liquid oral megestrol formulation at about the same concentration per ml of megestrol. 46. The composition of claim 1 having a viscosity selected from the group consisting of from about 175 mPa s to about 1 mPa s, from about 150 mPa s to about 1 mPa, from about 125 mPa s to about 1 mPa s, from about 100 mPa s to about 1 mPa s, from about 75 mPa s to about 1 mPa s, from about 50 mPa s to about 1 mPa s, from about 25 mPa s to about 1 mPa s, from about 15 mPa s to about 1 mPa s, and from about 5 mPa s to about 1 mPa s. 47. A liquid oral megestrol acetate composition having a viscosity less than the viscosity of a standard commercial megestrol formulation. 48. The composition of claim 47, wherein the amount of megestrol acetate per ml is equal to or greater than the amount of megestrol acetate per ml of a standard commercial liquid oral megestrol acetate formulation. 49. The composition of claim 48, wherein the viscosity is selected from the group consisting of less than about {fraction (1/200)}, less than about {fraction (1/175)}, less than about {fraction (1/150)}, less than about {fraction (1/125)}, less than about {fraction (1/100)}, less than about {fraction (1/50)}, less than about {fraction (1/25)} of a standard commercial liquid oral megestrol formulation at about the same concentration per ml of megestrol acetate. 50. The composition of claim 1 having a viscosity selected from the group consisting of from about 175 mPa s to about 1 mPa s, from about 150 mPa s to about 1 mPa, from about 125 mPa s to about 1 mPa s, from about 100 mPa s to about 1 mPa s, from about 75 mPa s to about 1 mPa s, from about 50 mPa s to about 1 mPa s, from about 25 mPa s to about 1 mPa s, from about 15 mPa s to about 1 mPa s, and from about 5 mPa s to about 1 mPa s. 51. A megestrol acetate nanoparticulate composition comprising: (a) particles of megestrol acetate having an effective average particle size of less than about 2000 nm; and (b) associated with the surface thereof hydroxypropyl methylcellulose (HPMC) and dioctyl sodium sulfosuccinate (DOSS). 52. The composition of claim 51, wherein the ratio of megestrol acetate:HPMC is about 1:about 5 and the ratio of megestrol acetate:DOSS is about 1:about 100. 53. A method of making a nanoparticulate megestrol composition comprising contacting megestrol particles with at least one surface stabilizer for a time and under conditions sufficient to provide a nanoparticulate megestrol composition having an effective average particle size of less than about 2000 nm. 54. The method of claim 53, wherein said contacting comprising grinding. 55. The method of claim 54, wherein said grinding comprising wet grinding. 56. The method of claim 53, wherein said contacting comprises homogenizing. 57. The method of claim 53, wherein said contacting comprises: (a) dissolving the megestrol particles in a solvent; (b) adding the resulting megestrol solution to a solution comprising at least one surface stabilizer; and (c) precipitating the solubilized megestrol having at least one surface stabilizer associated with the surface thereof by the addition thereto of a non-solvent. 58. The method of claim 53, wherein the megestrol is selected from the group consisting of a crystalline phase, an amorphous phase, a semi-crystalline phase, a semi-amorphous phase, and mixtures thereof. 59. The method of claim 53, wherein the effective average particle size of the nanoparticulate megestrol particles is selected from the group consisting of less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 100 nm, less than about 75 nm, and less than about 50 mm. 60. The method of claim 53, wherein the megestrol is present in an amount selected from the group consisting of from about 99% to about 0.001%, from about 95% to about 0.5%, and from about 90% to about 0.5%, by weight, based on the total combined weight of the megestrol and at least one surface stabilizer, not including other excipients. 61. The method of claim 53, wherein at least one surface stabilizer is present in an amount selected from the group consisting of from about 0.5% to about 99.999%, from about 5.0% to about 99.9%, and from about 10% to about 99.5%, by weight, based on the total combined dry weight of the megestrol and at least one surface stabilizer, not including other excipients. 62. The method of claim 53, comprising at least two surface stabilizers, including a primary surface stabilizer and a secondary surface stabilizer. 63. The method of claim 62, wherein the primary surface stabilizer is selected from the group consisting of hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, and random copolymers of vinyl acetate and vinyl pyrrolidone 64. The method of claim 62, wherein the secondary surface stabilizer is selected from the group consisting of sodium lauryl sulfate and dioctyl sodium sulfosuccinate. 65. The method of claim 62, wherein the at least one secondary surface stabilizer is present in an amount selected from the group consisting of from about 0.01% to about 99%, from about 0.1% to about 95%, and from about 1% to about 90%, by weight, based on the total combined dry weight of the megestrol, at least one primary surface stabilizer, and at least one secondary surface stabilizer, not including other excipients. 66. The method of claim 53, wherein the surface stabilizer is selected from the group consisting of an anionic surface stabilizer, a cationic surface stabilizer, an ionic surface stabilizer, and a zwitterionic surface stabilizer. 67. The method of claim 66, wherein the at least one surface stabilizer is selected from the group consisting of cetyl pyridinium chloride, gelatin, casein, phosphatides, dextran, glycerol, gum acacia, cholesterol, tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glycerol monostearate, cetostearyl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, polyethylene glycols, dodecyl trimethyl ammonium bromide, polyoxyethylene stearates, colloidal silicon dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, hydroxypropyl celluloses, hydroxypropyl methylcellulose, carboxymethylcellulose sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylmethyl-cellulose phthalate, noncrystalline cellulose, magnesium aluminum silicate, triethanolamine, polyvinyl alcohol, polyvinylpyrrolidone, 4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide and formaldehyde, poloxamers; poloxamines, a charged phospholipid, dioctylsulfosuccinate, dialkylesters of sodium sulfosuccinic acid, sodium lauryl sulfate, alkyl aryl polyether sulfonates, mixtures of sucrose stearate and sucrose distearate, p-isononylphenoxypoly-(glycidol), decanoyl-N-methylglucamide; n-decyl P-D-glucopyranoside; n-decyl β-D-maltopyranoside; n-dodecyl β-D-glucopyranoside; n-dodecyl β-D-maltoside; heptanoyl-N-methylglucamide; n-heptyl-β-D-glucopyranoside; n-heptyl β-D-thioglucoside; n-hexyl β-D-glucopyranoside; nonanoyl-N-methylglucamide; n-noyl P-D-glucopyranoside; octanoyl-N-methylglucamide; n-octyl-p-D-glucopyranoside; octyl β-D-thioglucopyranoside; lysozyme, PEG-phospholipid, PEG-cholesterol, PEG-cholesterol derivative, PEG-vitamin A, PEG-vitamin E, and random copolymers of vinyl acetate and vinyl pyrrolidone. 68. The method of claim 66, wherein the at least one cationic surface stabilizer is selected from the group consisting of a polymer, a biopolymer, a polysaccharide, a cellulosic, an alginate, a nonpolymeric compound, and a phospholipid. 69. The method of claim 66, wherein the surface stabilizer is selected from the group consisting of polymethylmethacrylate trimethylammonium bromide, polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate, and hexadecyltrimethyl ammonium bromide, cationic lipids, sulfonium compounds, phosphonium compounds, quarternary ammonium compounds, benzyl-di(2-chloroethyl)ethylammonium bromide, coconut trimethyl ammonium chloride, coconut trimethyl ammonium bromide, coconut methyl dihydroxyethyl ammonium chloride, coconut methyl dihydroxyethyl ammonium bromide, decyl triethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride bromide, C12-15dimethyl hydroxyethyl ammonium chloride, C12-15dimethyl hydroxyethyl ammonium chloride bromide, coconut dimethyl hydroxyethyl ammonium chloride, coconut dimethyl hydroxyethyl ammonium bromide, myristyl trimethyl ammonium methyl sulphate, lauryl dimethyl benzyl ammonium chloride, lauryl dimethyl benzyl ammonium bromide, lauryl dimethyl (ethenoxy)4 ammonium chloride, lauryl dimethyl (ethenoxy)4 ammonium bromide, N-alkyl (C12-18)dimethylbenzyl ammonium chloride, N-alkyl (C14-18)dimethyl-benzyl ammonium chloride, N-tetradecylidmethylbenzyl ammonium chloride monohydrate, dimethyl didecyl ammonium chloride, N-alkyl and (C12-14) dimethyl 1-napthylmethyl ammonium chloride, trimethylammonium halide, alkyl-trimethylammonium salts, dialkyl-dimethylammonium salts, lauryl trimethyl ammonium chloride, ethoxylated alkyamidoalkyldialkylammonium salt, an ethoxylated trialkyl ammonium salt, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium, chloride monohydrate, N-alkyl(C12-14) dimethyl 1-naphthylmethyl ammonium chloride, dodecyldimethylbenzyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, C12 trimethyl ammonium bromides, C15 trimethyl ammonium bromides, C17 trimethyl ammonium bromides, dodecylbenzyl triethyl ammonium chloride, poly-diallyldimethylammonium chloride (DADMAC), dimethyl ammonium chlorides, alkyldimethylammonium halogenides, tricetyl methyl ammonium chloride, decyltrimethylammonium bromide, dodecyltriethylammonium bromide, tetradecyltrimethylammonium bromide, methyl trioctylammonium chloride, POLYQUAT 10™, tetrabutylammonium bromide, benzyl trimethylammonium bromide, choline esters, benzalkonium chloride, stearalkonium chloride compounds, cetyl pyridinium bromide, cetyl pyridinium chloride, halide salts of quaternized polyoxyethylalkylamines, MIRAPOL™, ALKAQUAT™, alkyl pyridinium salts; amines, amine salts, amine oxides, imide azolinium salts, protonated quaternary acrylamides, methylated quaternary polymers, and cationic guar. 70. The method of claim 53, wherein after preparation of the nanoparticulate megestrol composition, a second megestrol composition having an effective average particle size of greater than about 2 microns is combined with the nanoparticulate megestrol composition. 71. The method of claim 53, wherein either prior or subsequent to preparation of the nanoparticulate megestrol composition, at least one non-megestrol active agent is added to the nanoparticulate megestrol composition. 72. The method of claim 71, wherein said non-megestrol active agent is selected from the group consisting of amino acids proteins, peptides, nucleotides, anti-obesity drugs, nutraceuticals, dietary supplements, carotenoids, central nervous system stimulants, corticosteroids, elastase inhibitors, anti-fungals, alkylxanthine, oncology therapies, anti-emetics, analgesics, opioids, antipyretics, cardiovascular agents, anti-inflammatory agents, anthelmintics, anti-arrhythmic agents, antibiotics, anticoagulants, antidepressants, antidiabetic agents, antiepileptics, antihistamines, antihypertensive agents, antimuscarinic agents, antimycobacterial agents, antineoplastic agents, immunosuppressants, antithyroid agents, antiviral agents, anxiolytics, sedatives, astringents, alpha-adrenergic receptor blocking agents, beta-adrenoceptor blocking agents, blood products, blood substitutes, cardiac inotropic agents, contrast media, corticosteroids, cough suppressants, diagnostic agents, diagnostic imaging agents, diuretics, dopaminergics, haemostatics, immunological agents, lipid regulating agents, muscle relaxants, parasympathomimetics, parathyroid calcitonin and biphosphonates, prostaglandins, radio-pharmaceuticals, sex hormones, anti-allergic agents, stimulants, anoretics, sympathomimetics, thyroid agents, vasodilators, vasomodulator, xanthines, Mu receptor antagonists, Kappa receptor antagonists, non-narcotic analgesics, monoamine uptake inhibitors, adenosine regulating agents, cannabinoid derivatives, Substance P antagonists, neurokinin-1 receptor antagonists, and sodium channel blockers. 73. The method of claim 72, wherein said nutraceutical is selected from the group consisting of lutein, folic acid, fatty acids, fruit extracts, vegetable extracts, vitamin supplements, mineral supplements, phosphatidylserine, lipoic acid, melatonin, glucosamine/chondroitin, Aloe Vera, Guggul, glutamine, amino acids, green tea, lycopene, whole foods, food additives, herbs, phytonutrients, antioxidants, flavonoid constituents of fruits, evening primrose oil, flax seeds, fish oils, marine animal oils, and probiotics. 74. The method of any of claims 71, 72, or 73, wherein at least one non-megestrol active agent has an effective average particle size of less than about 2 microns. 75. The method of any of claims 71, 72, or 73, wherein at least one non-megestrol active agent has an effective average particle size of greater than about 2 microns. 76. A method of treating a subject in need with a nanoparticulate megestrol formulation comprising administering to the subject an effective amount of a nanoparticulate composition comprising megestrol particles having at least one surface stabilizer associated with the surface thereof, wherein the megestrol particles have an effective average particle size of less than about 2000 nm. 77. The method of claim 76, wherein the condition to be treated is selected from the group consisting of neoplastic diseases, breast cancer, endometrial cancer, uterine cancer, cervical cancer, prostate cancer, renal cancer, hormone replacement therapy in post-menopausal women, endometriosis, hirsutism, dysmenorrhea, uterine bleeding, HIV wasting, cancer wasting, cachexia, anorexia, castration, and oral contraception. 78. The method of claim 76, wherein the nanoparticulate megestrol formulation is administered in the form of an oral suspension. 79. The method of claim 76, wherein a maximum blood plasma concentration of megestrol is attained in about 1 hour or less after administration of the nanoparticulate megestrol formulation in fasting subjects. 80. The method of claim 76, wherein a maximum blood plasma concentration of megestrol of at least about 700 ng/ml is obtained. 81. The method of claim 80, wherein the maximum blood plasma concentration of megestrol is at least about 700 ng/ml and is attained in less than 5 hours after administration of the nanoparticulate megestrol formulation. 82. The method of claim 76, wherein the maximum blood plasma concentration of megestrol is at least about 400 ng/ml and is attained in less than 5 hours after administration of the nanoparticulate megestrol formulation. 83. The method of claim 76, wherein the nanoparticulate megestrol formulation is administered in an amount providing from about 1 mg/day to about 1000 mg/day of megestrol. 84. The method of claim 83, wherein the nanoparticulate megestrol formulation is administered in an amount providing from about 40 mg/day to about 800 mg/day of megestrol. 85. The method of claim 83, wherein the nanoparticulate megestrol formulation is administered in an amount providing from about 500 mg/day to about 700 mg/day of megestrol. 86. The method of claim 76, wherein the amount of nanoparticulate megestrol formulation is 575 mg/day, 625 mg/day or 675 mg/day. 87. The method of claim 76, wherein the amount of nanoparticulate megestrol formulation is 575 mg/day. 88. The method of claim 76, wherein the megestrol is selected from the group consisting of a crystalline phase, an amorphous phase, a semi-crystalline phase, a semi-amorphous phase, and mixtures thereof. 89. The method of claim 76, wherein the effective average particle size of the nanoparticulate megestrol particles is selected from the group consisting of less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 100 nm, less than about 75 nm, and less than about 50 nm. 90. The method of claim 76, wherein the composition is formulated for administration selected from the group consisting of oral, pulmonary, rectal, opthalmic, colonic, parenteral, intracisternal, intravaginal, intraperitoneal, local, buccal, nasal, and topical administration. 91. The method of claim 76, wherein the composition further comprises one or more pharmaceutically acceptable excipients, carriers, or a combination thereof. 92. The method of claim 76, wherein the megestrol is present in an amount selected from the group consisting of from about 99% to about 0.01%, from about 95% to about 0.5%, and from about 90% to about 0.5%, by weight, based on the total combined weight of the megestrol and at least one surface stabilizer, not including other excipients. 93. The method of claim 76, wherein the at least one surface stabilizer is present in an amount selected from the group consisting of from about 0.01% to about 99.5% by weight, from about 0.1% to about 95% by weight, and from about 0.5% to about 90% by weight, based on the total combined dry weight of the megestrol and at least one surface stabilizer, not including other excipients. 94. The method of claim 76, comprising at least one primary surface stabilizer and at least one secondary surface stabilizer. 95. The method of claim 94, wherein the primary surface stabilizer is selected from the group consisting of hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, and random copolymers of vinyl acetate and vinyl pyrrolidone 96. The method of claim 94, wherein the secondary surface stabilizer is selected from the group consisting of sodium lauryl sulfate and dioctyl sodium sulfosuccinate. 97. The method of claim 94, wherein the at least one secondary surface stabilizer is present in an amount selected from the group consisting of from about 0.01% to about 99%, from about 0.1% to about 95%, and from about 1% to about 90%, by weight, based on the total combined dry weight of the megestrol, at least one primary surface stabilizer, and at least one secondary surface stabilizer, not including other excipients. 98. The method of claim 76, wherein the surface stabilizer is selected from the group consisting of an anionic surface stabilizer, a cationic surface stabilizer, and an ionic surface stabilizer. 99. The method of claim 98, wherein the at least one surface stabilizer is selected from the group consisting of cetyl pyridinium chloride, gelatin, casein, phosphatides, dextran, glycerol, gum acacia, cholesterol, tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glycerol monostearate, cetostearyl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, polyethylene glycols, dodecyl trimethyl ammonium bromide, polyoxyethylene stearates, colloidal silicon dioxide, phosphates, sodium dodecylsulfate, carboxymethylcellulose calcium, hydroxypropyl celluloses, hydroxypropyl methylcellulose, carboxymethylcellulose sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylmethyl-cellulose phthalate, noncrystalline cellulose, magnesium aluminum silicate, triethanolamine, polyvinyl alcohol, polyvinylpyrrolidone, 4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide and formaldehyde, poloxamers; poloxamines, a charged phospholipid, dioctylsulfosuccinate, dialkylesters of sodium sulfosuccinic acid, sodium lauryl sulfate, alkyl aryl polyether sulfonates, mixtures of sucrose stearate and sucrose distearate, p-isononylphenoxypoly-(glycidol), decanoyl-N-methylglucamide; n-decyl β-D-glucopyranoside; n-decyl β-D-maltopyranoside; n-dodecyl β-D-glucopyranoside; n-dodecyl β-D-maltoside; heptanoyl-N-methylglucamide; n-heptyl-β-D-glucopyranoside; n-heptyl β-D-thioglucoside; n-hexyl β-D-glucopyranoside; nonanoyl-N-methylglucamide; n-noyl β-D-glucopyranoside; octanoyl-N-methylglucamide; n-octyl-p-D-glucopyranoside; octyl β-D-thioglucopyranoside; lysozyme, PEG-phospholipid, PEG-cholesterol, PEG-cholesterol derivative, PEG-vitamin A, PEG-vitamin E, and random copolymers of vinyl acetate and vinyl pyrrolidone. 100. The method of claim 98, wherein the at least one cationic surface stabilizer is selected from the group consisting of a polymer, a biopolymer, a polysaccharide, a cellulosic, an alginate, a nonpolymeric compound, and a phospholipid. 101. The method of claim 98, wherein the surface stabilizer is selected from the group consisting of benzalkonium chloride, polymethylmethacrylate trimethylammonium bromide, polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate, and hexadecyltrimethyl ammonium bromide. 102. The method of claim 98, wherein the surface stabilizer is selected from the group consisting of cationic lipids, sulfonium compounds, phosphonium compounds, quarternary ammonium compounds, benzyl-di(2-chloroethyl)ethylammonium bromide, coconut trimethyl ammonium chloride, coconut trimethyl ammonium bromide, coconut methyl dihydroxyethyl ammonium chloride, coconut methyl dihydroxyethyl ammonium bromide, decyl triethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride bromide, C12-15dimethyl hydroxyethyl ammonium chloride, C12-15dimethyl hydroxyethyl ammonium chloride bromide, coconut dimethyl hydroxyethyl ammonium chloride, coconut dimethyl hydroxyethyl ammonium bromide, myristyl trimethyl ammonium methyl sulphate, lauryl dimethyl benzyl ammonium chloride, lauryl dimethyl benzyl ammonium bromide, lauryl dimethyl (ethenoxy)4 ammonium chloride, lauryl dimethyl (ethenoxy)4 ammonium bromide, N-alkyl (C12-18)dimethylbenzyl ammonium chloride, N-alkyl (C14-18)dimethyl-benzyl ammonium chloride, N-tetradecylidmethylbenzyl ammonium chloride monohydrate, dimethyl didecyl ammonium chloride, N-alkyl and (C12-14) dimethyl 1-napthylmethyl ammonium chloride, trimethylammonium halide, alkyl-trimethylammonium salts, dialkyl-dimethylammonium salts, lauryl trimethyl ammonium chloride, ethoxylated alkyamidoalkyldialkylammonium salt, an ethoxylated trialkyl ammonium salt, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium, chloride monohydrate, N-alkyl(C12-14) dimethyl 1-naphthylmethyl ammonium chloride, dodecyldimethylbenzyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, C12 trimethyl ammonium bromides, C15 trimethyl ammonium bromides, C17 trimethyl ammonium bromides, dodecylbenzyl triethyl ammonium chloride, poly-diallyldimethylammonium chloride (DADMAC), dimethyl ammonium chlorides, alkyldimethylammonium halogenides, tricetyl methyl ammonium chloride, decyltrimethylammonium bromide, dodecyltriethylammonium bromide, tetradecyltrimethylammonium bromide, methyl trioctylammonium chloride, POLYQUAT 10™, tetrabutylammonium bromide, benzyl trimethylammonium bromide, choline esters, benzalkonium chloride, stearalkonium chloride compounds, cetyl pyridinium bromide, cetyl pyridinium chloride, halide salts of quaternized polyoxyethylalkylamines, MIRAPOL™, ALKAQUAT™, alkyl pyridinium salts; amines, amine salts, amine oxides, imide azolinium salts, protonated quaternary acrylamides, methylated quaternary polymers, and cationic guar. 103. A therapeutic method comprising orally administering to a mammalian subject in need an effective amount of a composition comprising megestrol acetate formulated in such a way as to provide a blood plasma concentration profile, after an initial dose of said composition, with a Tmax of said megestrol acetate of less than 5 hours, and a Cmax of said megestrol acetate of at least 30 ng/ml. 104. The method of claim 103, wherein said Tmax of megestrol acetate is not greater than 3 hours. 105. The method of claim 103, wherein said subject is a human. 106. The method of claim 103, wherein said composition is an oral suspension. 107. The method of claim 103, wherein said composition is a tablet. 108. The method of claim 103, wherein said method is used to treat cachexia. 109. A method of providing megestrol to a fed human subject comprising administering a nanoparticulate megestrol formulation, wherein absorption comprises AUC0-t in an amount of about 3000 ng hr/ml to about 15,000 ng hr/ml. 110. The method of claim 109, wherein Cmax is about 300 ng/ml to about 1700 ng/ml. 111. A method of providing megestrol to a fasted human subject comprising administering a nanoparticulate megestrol formulation, wherein absorption comprises AUC0-t in an amount of about 2000 ng hr/ml to about 9000 ng hr/ml. 112. The method of claim 111, wherein Cmax is about 300 ng/ml to about 2000 ng/ml.
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This application is a continuation-in-part of application Ser. No. 10/412,669 filed April, 14, 2003, which claims the priority benefit of U.S. provisional patent application Ser. No. 60/371,680, filed Apr. 12, 2002, and U.S. provisional patent application No. 60/430,348, filed Dec. 3, 2002. FIELD OF THE INVENTION The present invention relates to a nanoparticulate composition comprising megestrol and preferably at least one surface stabilizer associated with the surface of the drug. The nanoparticulate megestrol particles have an effective average particle size of less than about 2000 nm. BACKGROUND OF THE INVENTION A. Background Regarding Nanoparticulate Compositions Nanoparticulate compositions, first described in U.S. Pat. No. 5,145,684 (“the '684 patent”), are particles consisting of a poorly soluble therapeutic or diagnostic agent having adsorbed onto the surface thereof a non-crosslinked surface stabilizer. The '684 patent does not describe nanoparticulate compositions of megestrol. Methods of making nanoparticulate compositions are described, for example, in U.S. Pat. Nos. 5,518,187 and 5,862,999, both for “Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,718,388, for “Continuous Method of Grinding Pharmaceutical Substances;” and U.S. Pat. No. 5,510,118 for “Process of Preparing Therapeutic Compositions Containing Nanoparticles.” Nanoparticulate compositions are also described, for example, in U.S. Pat. No. 5,298,262 for “Use of Ionic Cloud Point Modifiers to Prevent Particle Aggregation During Sterilization;” U.S. Pat. No. 5,302,401 for “Method to Reduce Particle Size Growth During Lyophilization;” U.S. Pat. No. 5,318,767 for “X-Ray Contrast Compositions Useful in Medical Imaging;” U.S. Pat. No. 5,326,552 for “Novel Formulation For Nanoparticulate X-Ray Blood Pool Contrast Agents Using High Molecular Weight Non-ionic Surfactants;” U.S. Pat. No. 5,328,404 for “Method of X-Ray Imaging Using Iodinated Aromatic Propanedioates;” U.S. Pat. No. 5,336,507 for “Use of Charged Phospholipids to Reduce Nanoparticle Aggregation;” U.S. Pat. No. 5,340,564 for “Formulations Comprising Olin 10-G to Prevent Particle Aggregation and Increase Stability;” U.S. Pat. No. 5,346,702 for “Use of Non-Ionic Cloud Point Modifiers to Minimize Nanoparticulate Aggregation During Sterilization;” U.S. Pat. No. 5,349,957 for “Preparation and Magnetic Properties of Very Small Magnetic-Dextran Particles;” U.S. Pat. No. 5,352,459 for “Use of Purified Surface Modifiers to Prevent Particle Aggregation During Sterilization;” U.S. Pat. No. 5,399,363 and U.S. Pat. No. 5,494,683, both for “Surface Modified Anticancer Nanoparticles;” U.S. Pat. No. 5,401,492 for “Water Insoluble Non-Magnetic Manganese Particles as Magnetic Resonance Enhancement Agents;” U.S. Pat. No. 5,429,824 for “Use of Tyloxapol as a Nanoparticulate Stabilizer;” U.S. Pat. No. 5,447,710 for “Method for Making Nanoparticulate X-Ray Blood Pool Contrast Agents Using High Molecular Weight Non-ionic Surfactants;” U.S. Pat. No. 5,451,393 for “X-Ray Contrast Compositions Useful in Medical Imaging;” U.S. Pat. No. 5,466,440 for “Formulations of Oral Gastrointestinal Diagnostic X-Ray Contrast Agents in Combination with Pharmaceutically Acceptable Clays;” U.S. Pat. No. 5,470,583 for “Method of Preparing Nanoparticle Compositions Containing Charged Phospholipids to Reduce Aggregation;” U.S. Pat. No. 5,472,683 for “Nanoparticulate Diagnostic Mixed Carbamic Anhydrides as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,500,204 for “Nanoparticulate Diagnostic Dimers as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,518,738 for “Nanoparticulate NSAID Formulations;” U.S. Pat. No. 5,521,218 for “Nanoparticulate Iododipamide Derivatives for Use as X-Ray Contrast Agents;” U.S. Pat. No. 5,525,328 for “Nanoparticulate Diagnostic Diatrizoxy Ester X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,543,133 for “Process of Preparing X-Ray Contrast Compositions Containing Nanoparticles;” U.S. Pat. No. 5,552,160 for “Surface Modified NSAID Nanoparticles;” U.S. Pat. No. 5,560,931 for “Formulations of Compounds as Nanoparticulate Dispersions in Digestible Oils or Fatty Acids;” U.S. Pat. No. 5,565,188 for “Polyalkylene Block Copolymers as Surface Modifiers for Nanoparticles;” U.S. Pat. No. 5,569,448 for “Sulfated Non-ionic Block Copolymer Surfactant as Stabilizer Coatings for Nanoparticle Compositions;” U.S. Pat. No. 5,571,536 for “Formulations of Compounds as Nanoparticulate Dispersions in Digestible Oils or Fatty Acids;” U.S. Pat. No. 5,573,749 for “Nanoparticulate Diagnostic Mixed Carboxylic Anydrides as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,573,750 for “Diagnostic Imaging X-Ray Contrast Agents;” U.S. Pat. No. 5,573,783 for “Redispersible Nanoparticulate Film Matrices With Protective Overcoats;” U.S. Pat. No. 5,580,579 for “Site-specific Adhesion Within the GI Tract Using Nanoparticles Stabilized by High Molecular Weight, Linear Poly(ethylene Oxide) Polymers;” U.S. Pat. No. 5,585,108 for “Formulations of Oral Gastrointestinal Therapeutic Agents in Combination with Pharmaceutically Acceptable Clays;” U.S. Pat. No. 5,587,143 for “Butylene Oxide-Ethylene Oxide Block Copolymers Surfactants as Stabilizer Coatings for Nanoparticulate Compositions;” U.S. Pat. No. 5,591,456 for “Milled Naproxen with Hydroxypropyl Cellulose as Dispersion Stabilizer;” U.S. Pat. No. 5,593,657 for “Novel Barium Salt Formulations Stabilized by Non-ionic and Anionic Stabilizers;” U.S. Pat. No. 5,622,938 for “Sugar Based Surfactant for Nanocrystals;” U.S. Pat. No. 5,628,981 for “Improved Formulations of Oral Gastrointestinal Diagnostic X-Ray Contrast Agents and Oral Gastrointestinal Therapeutic Agents;” U.S. Pat. No. 5,643,552 for “Nanoparticulate Diagnostic Mixed Carbonic Anhydrides as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,718,388 for “Continuous Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,718,919 for “Nanoparticles Containing the R(−)Enantiomer of Ibuprofen;” U.S. Pat. No. 5,747,001 for “Aerosols Containing Beclomethasone Nanoparticle Dispersions;” U.S. Pat. No. 5,834,025 for “Reduction of Intravenously Administered Nanoparticulate Formulation Induced Adverse Physiological Reactions;” U.S. Pat. No. 6,045,829 “Nanocrystalline Formulations of Human Immunodeficiency Virus (HIV) Protease Inhibitors Using Cellulosic Surface Stabilizers;” U.S. Pat. No. 6,068,858 for “Methods of Making Nanocrystalline Formulations of Human Immunodeficiency Virus (HIV) Protease Inhibitors Using Cellulosic Surface Stabilizers;” U.S. Pat. No. 6,153,225 for “Injectable Formulations of Nanoparticulate Naproxen;” U.S. Pat. No. 6,165,506 for “New Solid Dose Form of Nanoparticulate Naproxen;” U.S. Pat. No. 6,221,400 for “Methods of Treating Mammals Using Nanocrystalline Formulations of Human Immunodeficiency Virus (HIV) Protease Inhibitors;” U.S. Pat. No. 6,264,922 for “Nebulized Aerosols Containing Nanoparticle Dispersions;” U.S. Pat. No. 6,267,989 for “Methods for Preventing Crystal Growth and Particle Aggregation in Nanoparticle Compositions;” U.S. Pat. No. 6,270,806 for “Use of PEG-Derivatized Lipids as Surface Stabilizers for Nanoparticulate Compositions;” U.S. Pat. No. 6,316,029 for “Rapidly Disintegrating Solid Oral Dosage Form,” U.S. Pat. No. 6,375,986 for “Solid Dose Nanoparticulate Compositions Comprising a Synergistic Combination of a Polymeric Surface Stabilizer and Dioctyl Sodium Sulfosuccinate,” U.S. Pat. No. 6,428,814 for “Bioadhesive Nanoparticulate Compositions Having Cationic Surface Stabilizers;” U.S. Pat. No. 6,431,478 for “Small Scale Mill;” and U.S. Pat. No. 6,432,381 for “Methods for Targeting Drug Delivery to the Upper and/or Lower Gastrointestinal Tract,” all of which are specifically incorporated by reference. In addition, U.S. Patent Application No. 20020012675 A1, published on Jan. 31, 2002, for “Controlled Release Nanoparticulate Compositions,” describes nanoparticulate compositions, and is specifically incorporated by reference. Amorphous small particle compositions are described, for example, in U.S. Pat. No. 4,783,484 for “Particulate Composition and Use Thereof as Antimicrobial Agent;” U.S. Pat. No. 4,826,689 for “Method for Making Uniformly Sized Particles from Water-Insoluble Organic Compounds;” U.S. Pat. No. 4,997,454 for “Method for Making Uniformly-Sized Particles From Insoluble Compounds;” U.S. Pat. No. 5,741,522 for “Ultrasmall, Non-aggregated Porous Particles of Uniform Size for Entrapping Gas Bubbles Within and Methods;” and U.S. Pat. No. 5,776,496, for “Ultrasmall Porous Particles for Enhancing Ultrasound Back Scatter.” B. Background Regarding Megestrol Megestrol acetate, also known as 17α-acetyloxy-6-methylpregna-4,6-diene-3,20-dione, is a synthetic progestin with progestational effects similar to those of progesterone. It is used in abortion, endometriosis, and menstrual disorders. It is also used in a variety of situations including treatment of breast cancer, contraception, and hormone replacement therapy in post-menopausal women. Megestrol acetate is also frequently prescribed as an appetite enhancer for patients in a wasting state, such as HIV wasting, cancer wasting, or anorexia. In combination with ethynyl estradiol it acts as an oral contraceptive. It is also administered to subjects after castration. Megestrol acetate is marketed by Par Pharmaceuticals, Inc. and under the brand name Megace® by Bristol Myers Squibb Co. Typical commercial formulations are relatively large volume. For example, Par Pharmaceuticals, Inc. megestrol acetate oral suspension contains 40 mg of micronized megestrol acetate per ml, and the package insert recommends an initial adult dosage of megestrol acetate oral suspension of 800 mg/day (20 mL/day). The commercial formulations of megestrol acetate are highly viscous suspensions, which have a relatively long residence time in the mouth and any tubing. Highly viscous substances are not well accepted by patient populations, particularly patients suffering wasting and those that are intubated. U.S. Pat. No. 6,028,065 for “Flocculated Suspension of Megestrol Acetate,” assigned to Pharmaceutical Resources, Inc. (Spring Valley, N.Y.), describes oral pharmaceutical micronized megestrol acetate compositions in the form of a stable flocculated suspension in water. The compositions comprise at least one compound selected from the group consisting of polyethylene glycol, propylene glycol, glycerol, and sorbitol; and a surfactant, wherein polysorbate and polyethylene glycol are not simultaneously present. U.S. Pat. No. 6,268,356, also for “Flocculated Suspension of Megestrol Acetate,” and assigned to Pharmaceutical Resources, Inc., describes methods of treating a neoplastic condition comprising administering the composition of U.S. Pat. No. 6,028,065. Another company that has developed a megestrol formulation is Eurand (Milan, Italy). Eurand's formulation is a modified form of megestrol acetate having increased bioavailability. Eurand structurally modifies poorly soluble drugs to increase their bioavailability. See www.eurand.com. For megestrol acetate, Eurand uses its' “Biorise” process, in which a New Physical Entity (NPE) is created by physically breaking down megestrol's crystal lattice. This results in drug nanocrystals and/or amorphous drug, which are then stabilized with biologically inert carriers. Eurand uses three types of carriers: swellable microparticles, composite swellable microparticles, and cyclodextrins. See e.g., http://www.eurand.com/page.php?id=39. Such a delivery system can be undesirable, as “breaking down” an active agent's crystalline structure can modify the activity of the active agent. A drug delivery system which does not alter the structure of the active agent is preferable. Among the progestins, megestrol acetate is one of the few that can be administered orally because of its reduced first-pass (hepatic) metabolism, compared to the parent hormone. In addition, it is claimed to be superior to 19-nor compounds as an antifertility agent because it has less effect on the endometrium and vagina. See Stedman 's Medical Dictionary, 25th Ed., page 935 (Williams & Wilkins, MD 1990). There is a need in the art for megestrol formulations which exhibit increased bioavailability, less variability, and/or less viscosity as compared to conventional microparticulate megestrol formulations. The present invention satisfies these needs. SUMMARY OF THE INVENTION The invention relates to nanoparticulate megestrol compositions. The compositions comprise megestrol and preferably at least one surface stabilizer associated with the surface of the megestrol particles. The nanoparticulate megestrol particles have an effective average particle size of less than about 2000 nm. Another aspect of the invention is directed to pharmaceutical compositions comprising a nanoparticulate megestrol composition of the invention. The pharmaceutical compositions preferably comprise megestrol, at least one surface stabilizer, and a pharmaceutically acceptable carrier, as well as any desired excipients. This invention further discloses a method of making a nanoparticulate megestrol composition according to the invention. Such a method comprises contacting megestrol particles and at least one surface stabilizer for a time and under conditions sufficient to provide a nanoparticulate megestrol composition. The one or more surface stabilizers can be contacted with megestrol either before, during, or after size reduction of the megestrol. The present invention is also directed to methods of treatment using the nanoparticulate compositions of the invention for conditions such as endometriosis, dysmenorrhea, hirsutism, uterine bleeding, neoplastic diseases, methods of appetite enhancement, contraception, hormone replacement therapy, and treating patients following castration. Such methods comprises administering to a subject a therapeutically effective amount of a nanoparticulate megestrol composition according to the invention. Finally, the present invention is directed to megestrol acetate compositions with improved physical (viscosity) and pharmacokinetic profiles (such as less variability) over traditional forms of megestrol acetate. Both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. Other objects, advantages, and novel features will be readily apparent to those skilled in the art from the following detailed description of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1: Illustrates viscosity in units of mPa s as a function of concentration. Circles indicate the experimental values and the line illustrates the expected trend; FIG. 2: Illustrates viscosity in units of Pa s as a function of shear rate for two commercial samples, Bristol Myers Squibb and Par Pharmaceuticals, both at an active concentration of 40 mg/mL; and FIG. 3: Shows a photograph of, from left to right, a nanoparticulate dispersion of megestrol acetate, a commercial sample of megestrol acetate marketed by Par Pharmaceuticals, and a commercial sample of megestrol acetate marketed by Bristol Myers Squibb. FIG. 4: The figure graphically shows the comparative bioavailability (via plasma concentration (ng/mL)) of several nanoparticulate megestrol compositions (575 mg/5 ml, 625 mg/5 ml and 675 mg/5 ml) versus a conventional megestrol acetate marketed by Bristol Myers Squibb. FIG. 5: The figure graphically shows on a natural log scale the comparative bioavailability (via plasma concentration (ng/mL)) of several nanoparticulate megestrol compositions (575 mg/5 ml, 625 mg/5 ml and 675 mg/5 ml) versus a conventional megestrol acetate marketed by Bristol Myers Squibb. DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to nanoparticulate compositions comprising megestrol particles having an effective average particle size of less than about 2 microns. The compositions comprise megestrol and preferably at least one surface stabilizer associated with the surface of the drug. As taught in the '684 patent, not every combination of surface stabilizer and active agent will result in a stable nanoparticulate composition. It was surprisingly discovered that stable nanoparticulate megestrol compositions can be made. For example, nanoparticulate megestrol compositions with hydroxypropyl methylcellulose (HPMC) and sodium lauryl sulfate (SLS) as surface stabilizers remained stable in an electrolyte solution mimicking the physiological pH of the stomach. Nanoparticulate megestrol compositions comprising HPMC and SLS are stable for several weeks at temperatures up to 40° C. with only minimal particle size growth. In addition, nanoparticulate megestrol compositions with hydroxypropylcellulose (HPC) and dioctyl sodium sulfosuccinate (DOSS) as surface stabilizers, HPMC and DOSS as surface stabilizers, polyvinylpyrrolidone (PVP) and DOSS as surface stabilizers, and Plasdone® S630 and DOSS as surface stabilizers were stable in electrolyte fluids and exhibited acceptable physical stability at 5° C. for 4 weeks. (Plasdone® S630 (ISP) is a random copolymer of vinyl acetate and vinyl pyrrolidone.) Moreover, the nanoparticulate megestrol/HPMC/SLS and nanoparticulate megestrol/HPMC/DOSS compositions also exhibited acceptable physical stability at 25° C. and 40° C. for 4 weeks. Advantages of the nanoparticulate megestrol compositions of the invention include, but are not limited to: (1) low viscosity liquid nanoparticulate megestrol dosage forms; (2) for liquid nanoparticulate megestrol compositions having a low viscosity better subject compliance due to the perception of a lighter formulation which is easier to consume and digest; (3) for liquid nanoparticulate megestrol compositions having a low viscosity—ease of dispensing because one can use a cup or a syringe; (4) faster onset of action; (5) smaller doses of megestrol required to obtain the same pharmacological effect as compared to conventional microcrystalline forms of megestrol; (6) increased bioavailability as compared to conventional microcrystalline forms of megestrol; (7) substantially similar pharmacokinetic profiles of the nanoparticulate megestrol compositions when administered in the fed versus the fasted state; (8) bioequivalency of the nanoparticulate megestrol compositions when administered in the fed versus the fasted state; (9) redispersibility of the nanoparticulate megestrol particles present in the compositions of the invention following administration; (10) bioadhesive nanoparticulate megestrol compositions; (11) improved pharmacokinetic profiles, such as more rapid megestrol absorption, greater megestrol absorption, and longer megestrol dose retention in the blood following administration; (12) the nanoparticulate megestrol compositions can be used in conjunction with other active agents; (13) the nanoparticulate megestrol compositions preferably exhibit an increased rate of dissolution as compared to conventional microcrystalline forms of megestrol; (14) improved performance characteristics for oral, intravenous, subcutaneous, or intramuscular injection, such as higher dose loading and smaller tablet or liquid dose volumes; (15) the nanoparticulate megestrol compositions are suitable for parenteral administration; (16) the nanoparticulate megestrol compositions can be sterile filtered; and (17) the nanoparticulate megestrol compositions do not require organic solvents or pH extremes. The present invention is described herein using several definitions, as set forth below and throughout the application. “About” will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which the term is used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, “about” will mean up to plus or minus 10% of the particular term. As used herein with reference to stable drug particles, “stable” means that the megestrol particles do not appreciably flocculate or agglomerate due to interparticle attractive forces or otherwise increase in particle size. “Conventional active agents or drugs” refers to non-nanoparticulate compositions of active agents or solubilized active agents or drugs. Non-nanoparticulate active agents have an effective average particle size of greater than about 2 microns. A. Preferred Characteristics of the Nanoparticulate Megestrol Compositions of the Invention 1. Low Viscosity Typical commercial formulations of megestrol, such as Megace®, are relatively large volume, highly viscous substances that are not well accepted by patient populations, particularly subjects suffering from wasting. “Wasting” is a condition in which a subject finds it difficult to eat because, for example, food makes the subject nauseous. A highly viscous medicine is not compatible with treating such a condition, as frequently the highly viscous substance can cause additional nausea. Moreover, viscous solutions can be problematic in parenteral administration because these solutions require a slow syringe push and can stick to tubing. In addition, conventional formulations of poorly water-soluble active agents, such as megestrol, tend to be unsafe for intravenous administration techniques, which are used primarily in conjunction with highly water-soluble substances. Liquid dosage forms of the nanoparticulate megestrol compositions of the invention provide significant advantages over conventional liquid megestrol dosage forms. The low viscosity and silky texture of liquid dosage forms of the nanoparticulate megestrol compositions of the invention results in advantages in both preparation and use. These advantages include, for example: (1) better subject compliance due to the perception of a lighter formulation which is easier to consume and digest; (2) ease of dispensing because one can use a cup or a syringe; (3) potential for formulating a higher concentration of megestrol resulting in a smaller dosage volume and thus less volume for the subject to consume; and (4) easier overall formulation concerns. Liquid megestrol dosage forms which are easier to consume are especially important when considering juvenile patients, terminally ill patients, and patients suffering from gastrointestinal tract dysfunction or other conditions where nausea and vomiting are symptoms. For example, patients suffering from cancer or AIDS-related complications are commonly hypermetabolic and, at various stages of disease, exhibit gastrointestinal dysfunction. Additionally, drugs used to treat these conditions often cause nausea and vomiting. Viscous or gritty formulations, and those that require a relatively large dosage volume, are not well tolerated by patient populations suffering from wasting associated with these diseases because the formulations can exacerbate nausea and encourage vomiting. The viscosities of liquid dosage forms of nanoparticulate megestrol according to the invention are preferably less than about {fraction (1/200)}, less than about {fraction (1/175)}, less than about {fraction (1/150)}, less than about {fraction (1/125)}, less than about {fraction (1/100)}, less than about {fraction (1/75)}, less than about {fraction (1/50)}, or less than about {fraction (1/25)} of existing commercial liquid oral megestrol acetate compositions, e.g. Megace®, at about the same concentration per ml of megestrol. Typically the viscosity of liquid nanoparticulate megestrol dosage forms of the invention is from about 175 mPa s to about 1 mPa s, from about 150 mPa s to about 1 mPa, from about 125 mPa s to about 1 mPa s, from about 100 mPa s to about 1 mPa s, from about 75 mPa s to about 1 mPa s, from about 50 mPa s to about 1 mPa s, from about 25 mPa s to about 1 mPa s, from about 15 mPa s to about 1 mPa s, or from about 5 mPa s to about 1 mPa s. Such a viscosity is much more attractive for subject consumption and may lead to better overall subject compliance. Viscosity is concentration and temperature dependent. Typically, a higher concentration results in a higher viscosity, while a higher temperature results in a lower viscosity. Viscosity as defined above refers to measurements taken at about 20° C. (The viscosity of water at 20° C. is 1 mPa s.) The invention encompasses equivalent viscosities measured at different temperatures. A viscosity of 1.5 mPa s for a nanoparticulate megestrol dispersion having a concentration of 30 mg/mL, measured at 20° C., was obtained by the inventors. An equivalent viscosity at 4% active agent concentration would be 1.7 mPa s. Higher and lower viscosities can be obtained by varying the temperature and concentration of megestrol. Another important aspect of the invention is that the nanoparticulate megestrol compositions of the invention are not turbid. “Turbid,” as used herein refers to the property of particulate matter that can be seen with the naked eye or that which can be felt as “gritty.” The nanoparticulate megestrol compositions of the invention can be poured out of or extracted from a container as easily as water, whereas a conventional standard commercial (i.e., non-nanoparticulate or solubilized) megestrol liquid dosage form exhibits notably more “sluggish” characteristics. The liquid formulations of this invention can be formulated for dosages in any volume but preferably equivalent or smaller volumes than existing commercial formulations. 2. Fast Onset of Activity The use of conventional formulations of megestrol is not ideal due to delayed onset of action. In contrast, the nanoparticulate megestrol compositions of the invention exhibit faster therapeutic effects. Preferably, following administration the nanoparticulate megestrol compositions of the invention have a Tmax of less than about 5 hours, less than about 4.5 hours, less than about 4 hours, less than about 3.5 hours, less than about 3 hours, less than about 2.75 hours, less than about 2.5 hours, less than about 2.25 hours, less than about 2 hours, less than about 1.75 hours, less than about 1.5 hours, less than about 1.25 hours, less than about 1.0 hours, less than about 50 minutes, less than about 40 minutes, less than about 30 minutes, less than about 25 minutes, less than about 20 minutes, less than about 15 minutes, or less than about 10 minutes. 3. Increased Bioavailability The nanoparticulate megestrol compositions of the invention preferably exhibit increased bioavailability and require smaller doses as compared to prior conventional megestrol compositions administered at the same dose. Any drug, including megestrol, can have adverse side effects. Thus, lower doses of megestrol which can achieve the same or better therapeutic effects as those observed with larger doses of conventional megestrol compositions are desired. Such lower doses can be realized with the nanoparticulate megestrol compositions of the invention because the greater bioavailability observed with the nanoparticulate megestrol compositions as compared to conventional drug formulations means that smaller doses of drug are required to obtain the desired therapeutic effect. Specifically, a once a day dose of about 375 mg/5 mL (75 mg/mL) of a nanoparticulate megestrol acetate composition is considered equivalent to an 800 mg dose of Megace®. Administration of nanoparticulate megestrol formulations of the present invention can exhibit bioavailability, as determined by AUC0-t, in an amount of about 3000 ng hr/ml to about 15,000 ng hr/ml, wherein Cmax is about 300 ng/ml to about 1400 ng/ml, 1500 ng/ml, 1600 ng/ml, 1645 ng/ml or 1700 ng/ml in a fed human subject and AUC0-t in an amount of about 2000 ng hr/ml to about 9000 ng hr/ml, wherein Cmax is about 300 ng/ml to about 2000 ng/ml in a fasted human subject. Preferably, nanoparticulate megestrol formulations of the present invention exhibit comparable bioavailability in a range of between about 75 and about 130%, more preferably between about 80% and about 125%, of the specified therapeutic parameter (e.g., AUC0-t or Cmax). 4. The Pharmacokinetic Profiles of the Nanoparticulate Megestrol Compositions of the Invention are not Substantially Affected by the Fed or Fasted State of the Subject Ingesting the Compositions The invention encompasses nanoparticulate megestrol compositions wherein the pharmacokinetic profile of the megestrol is not substantially affected by the fed or fasted state of a subject ingesting the composition. This means that there is no substantial difference in the quantity of megestrol absorbed or the rate of megestrol absorption when the nanoparticulate megestrol compositions are administered in the fed versus the fasted state. Thus, the invention encompasses nanoparticulate megestrol compositions that can substantially eliminate the effect of food on the pharmacokinetics of megestrol. The difference in absorption of the nanoparticulate megestrol composition of the invention, when administered in the fed versus the fasted state, is less than about 35%, less than about 30%, less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than about 5%, or less than about 3%. This is an especially important feature in treating patients with difficulty in maintaining a fed state. In addition, preferably the difference in the rate of absorption (i.e., Tmax) of the nanoparticulate megestrol compositions of the invention, when administered in the fed versus the fasted state, is less than about 100%, less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 20%, less than about 15%, less than about 10%, less than about 5%, less than about 3%, or essentially no difference. Benefits of a dosage form which substantially eliminates the effect of food include an increase in subject convenience, thereby increasing subject compliance, as the subject does not need to ensure that they are taking a dose either with or without food. 5. Redispersibility Profiles of the Nanoparticulate Megestrol Compositions of the Invention An additional feature of the nanoparticulate megestrol compositions of the invention is that the compositions redisperse such that the effective average particle size of the redispersed megestrol particles is less than about 2 microns. This is significant, as if upon administration the nanoparticulate megestrol particles present in the compositions of the invention did not redisperse to a substantially nanoparticulate particle size, then the dosage form may lose the benefits afforded by formulating megestrol into a nanoparticulate particle size. This is because nanoparticulate megestrol compositions benefit from the small particle size of megestrol; if the nanoparticulate megestrol particles do not redisperse into the small particle sizes upon administration, then “clumps” or agglomerated megestrol particles are formed. With the formation of such agglomerated particles, the bioavailability of the dosage form may fall. Preferably, the redispersed megestrol particles of the invention have an effective average particle size, by weight, of less than about 2 microns, less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 run, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 150 mm, less than about 100 nm, less than about 75 nm, or less than about 50 nm, as measured by light-scattering methods, microscopy, or other appropriate methods. Moreover, the nanoparticulate megestrol compositions of the invention exhibit dramatic redispersion of the nanoparticulate megestrol particles upon administration to a mammal, such as a human or animal, as demonstrated by reconstitution in a biorelevant aqueous media. Such biorelevant aqueous media can be any aqueous media that exhibit the desired ionic strength and pH, which form the basis for the biorelevance of the media. The desired pH and ionic strength are those that are representative of physiological conditions found in the human body. Such biorelevant aqueous media can be, for example, aqueous electrolyte solutions or aqueous solutions of any salt, acid, or base, or a combination thereof, which exhibit the desired pH and ionic strength. Biorelevant pH is well known in the art. For example, in the stomach, the pH ranges from slightly less than 2 (but typically greater than 1) up to 4 or 5. In the small intestine the pH can range from 4 to 6, and in the colon it can range from 6 to 8. Biorelevant ionic strength is also well known in the art. Fasted state gastric fluid has an ionic strength of about 0.1M while fasted state intestinal fluid has an ionic strength of about 0.14. See e.g., Lindahl et al., “Characterization of Fluids from the Stomach and Proximal Jejunum in Men and Women,” Pharm. Res., 14 (4): 497-502 (1997). It is believed that the pH and ionic strength of the test solution is more critical than the specific chemical content. Accordingly, appropriate pH and ionic strength values can be obtained through numerous combinations of strong acids, strong bases, salts, single or multiple conjugate acid-base pairs (i.e., weak acids and corresponding salts of that acid), monoprotic and polyprotic electrolytes, etc. Representative electrolyte solutions can be, but are not limited to, HCl solutions, ranging in concentration from about 0.001 to about 0.1 M, and NaCl solutions, ranging in concentration from about 0.001 to about 0.1 M, and mixtures thereof. For example, electrolyte solutions can be, but are not limited to, about 0.1 M HCl or less, about 0.01 M HCl or less, about 0.001 M HCl or less, about 0.1 M NaCl or less, about 0.01 M NaCl or less, about 0.001 M NaCl or less, and mixtures thereof. Of these electrolyte solutions, 0.01 M HCl and/or 0.1 M NaCl, are most representative of fasted human physiological conditions, owing to the pH and ionic strength conditions of the proximal gastrointestinal tract. Electrolyte concentrations of 0.001 M HCl, 0.01 M HCl, and 0.1 M HCl correspond to pH 3, pH 2, and pH 1, respectively. Thus, a 0.01 M HCl solution simulates typical acidic conditions found in the stomach. A solution of 0.1 M NaCl provides a reasonable approximation of the ionic strength conditions found throughout the body, including the gastrointestinal fluids, although concentrations higher than 0.1 M may be employed to simulate fed conditions within the human GI tract. Exemplary solutions of salts, acids, bases or combinations thereof, which exhibit the desired pH and ionic strength, include but are not limited to phosphoric acid/phosphate salts+sodium, potassium and calcium salts of chloride, acetic acid/acetate salts+sodium, potassium and calcium salts of chloride, carbonic acid/bicarbonate salts+sodium, potassium and calcium salts of chloride, and citric acid/citrate salts+sodium, potassium and calcium salts of chloride. 6. Bioadhesive Nanoparticulate Megestrol Compositions Bioadhesive nanoparticulate megestrol compositions of the invention comprise at least one cationic surface stabilizer, which are described in more detail below. Bioadhesive formulations of megestrol exhibit exceptional bioadhesion to biological surfaces, such as mucous. In the case of bioadhesive nanoparticulate megestrol compositions, the term “bioadhesion” is used to describe the adhesion between the nanoparticulate megestrol compositions and a biological substrate (i.e. gastrointestinal mucin, lung tissue, nasal mucosa, etc.). See e.g., U.S. Pat. No. 6,428,814 for “Bioadhesive Nanoparticulate Compositions Having Cationic Surface Stabilizers,” which is specifically incorporated by reference. The bioadhesive megestrol compositions of the invention are useful in any situation in which it is desirable to apply the compositions to a biological surface. The bioadhesive megestrol compositions coat the targeted surface in a continuous and uniform film which is invisible to the naked human eye. A bioadhesive nanoparticulate megestrol composition slows the transit of the composition, and some megestrol particles would also most likely adhere to tissue other than the mucous cells and therefore give a prolonged exposure to megestrol, thereby increasing absorption and the bioavailability of the administered dosage. 7. Pharmacokinetic Profiles of the Nanoparticulate Megestrol Compositions of the Invention The present invention also provides compositions of nanoparticulate megestrol having a desirable pharmacokinetic profile when administered to mammalian subjects. The desirable pharmacokinetic profile of the nanoparticulate megestrol compositions comprise the parameters: (1) that the Tmax of megestrol, when assayed in the plasma of the mammalian subject, is less than about 5 hours; and (2) a Cmax of megestrol is greater than about 30 ng/ml. Preferably, the Tmax parameter of the pharmacokinetic profile is not greater than about 3 hours. Most preferably, the Tmax parameter of the pharmacokinetic profile is not greater than about 2 hours. The desirable pharmacokinetic profile, as used herein, is the pharmacokinetic profile measured after the initial dose of megestrol. For example, in a subject receiving 40 mg of megestrol four times a day, the Tmax and Cmax after the initial dose must be less than about 5 hours and greater than about 30 ng/ml, respectively. The compositions can be formulated in any way as described below. Current formulations of megestrol include oral suspensions and tablets. According to the package insert of Megace®, the pharmacokinetic profile of the oral suspension contains parameters such that the median Tmax is 5 hours and the mean Cmax is 753 ng/ml. Further, the Tmax, and Cmax for the Megace® 40 mg tablet, after the initial dose, is 2.2 hours and 27.6 ng/ml, respectively. Physicians Desk Reference, 55th Ed., 2001. The nanoparticulate megestrol compositions of the invention simultaneously improve upon at least the Tmax and Cmax parameters of the pharmacokinetic profile of megestrol. In one embodiment, a threshold blood plasma concentration of megestrol of about 700 ng/ml is attained in less than about 5 hours after administration of the formulation, and preferably not greater than about 3 hours. Preferably, the Tmax of an administered dose of a nanoparticulate megestrol composition is less than that of a conventional standard commercial non-nanoparticulate megestrol composition, administered at the same dosage. In addition, preferably the Cmax of a nanoparticulate megestrol composition is greater than the Cmax of a conventional standard commercial non-nanoparticulate megestrol composition, administered at the same dosage. A preferred nanoparticulate megestrol composition of the invention exhibits in comparative pharmacokinetic testing with a standard commercial formulation of megestrol, such as Megace® oral suspension or tablet from Bristol Myers Squibb, a Tmax which is less than about 100%, less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 25%, less than about 20%, less than about 15%, or less than about 10% of the Tmax exhibited by the standard commercial formulation of megestrol. A preferred nanoparticulate megestrol composition of the invention exhibits in comparative pharmacokinetic testing with a standard commercial formulation of megestrol, such as Megace® oral suspension or tablet from Bristol Myers Squibb, a Cmax which is greater than about 5%, greater than about 10%, greater than about 15%, greater than about 20%, greater than about 30%, greater than about 40%, greater than about 50%, greater than about 60%, greater than about 70%, greater than about 80%, greater than about 90%, greater than about 100%, greater than about 110%, greater than about 120%, greater than about 130%, greater than about 140%, greater than about 150%, greater than about 200%, greater than about 500% or greater than about 800% than the Cmax exhibited by the standard commercial formulation of megestrol. There is no critical upper limit of blood plasma concentration so long as the dosage amounts set out below are not significantly exceeded. A suitable dose of megestrol, administered according to the method of the invention, is typically in the range of about 1 mg/day to about 1000 mg/day, or from about 40 mg/day to about 800 mg/day. In one embodiment, a nanoparticulate megestrol composition is administered at a dose of 575 mg/day. In other embodiments, the nanoparticulate megestrol composition is administered at doses of 625 mg/day or 675 mg/day. Preferably, the therapeutically effective amount of the nanoparticulate megestrol compositions of the invention is about ⅙, ⅕, ¼, ⅓, ½, ⅔, ¾ or ⅚ of the therapeutically effective amount of existing commercial megestrol formulations. Any standard pharmacokinetic protocol can be used to determine blood plasma concentration profile in humans following administration of a nanoparticulate megestrol composition, and thereby establish whether that composition meets the pharmacokinetic criteria set out herein. For example, a randomized single-dose crossover study can be performed using a group of healthy adult human subjects. The number of subjects should be sufficient to provide adequate control of variation in a statistical analysis, and is typically about 10 or greater, although for certain purposes a smaller group can suffice. Each subject receives by oral administration at time zero a single dose (e.g., 300 mg) of a test formulation of megestrol, normally at around 8 am following an overnight fast. The subjects continue to fast and remain in an upright position for about 4 hours after administration of the megestrol formulation. Blood samples are collected from each subject prior to administration (e.g., 15 minutes) and at several intervals after administration. For the present purpose it is preferred to take several samples within the first hour, and to sample less frequently thereafter. Illustratively, blood samples could be collected at 15, 30, 45, 60, and 90 minutes after administration, then every hour from 2 to 10 hours after administration. Additional blood samples may also be taken later, for example at 12 and 24 hours after administration. If the same subjects are to be used for study of a second test formulation, a period of at least 7 days should elapse before administration of the second formulation. Plasma is separated from the blood samples by centrifugation and the separated plasma is analyzed for megestrol by a validated high performance liquid chromatography (HPLC) procedure, such as for example Garver et al., J. Pharm. Sci. 74(6):664-667 (1985), the entirety of which is hereby incorporated by reference. Plasma concentrations of megestrol referenced herein are intended to mean total megestrol concentrations including both free and bound megestrol. Any formulation giving the desired pharmacokinetic profile is suitable for administration according to the present methods. Exemplary types of formulations giving such profiles are liquid dispersions and solid dose forms of nanoparticulate megestrol. Dispersions of megestrol have proven to be stable at temperatures up to 50° C. If the liquid dispersion medium is one in which the nanoparticulate megestrol has very low solubility, the nanoparticulate megestrol particles are present as suspended particles. The smaller the megestrol particles, the higher the probability that the formulation will exhibit the desired pharmacokinetic profile. 8. Combination Pharmacokinetic Profile Compositions In yet another embodiment of the invention, a first nanoparticulate megestrol composition providing a desired pharmacokinetic profile is co-administered, sequentially administered, or combined with at least one other megestrol composition that generates a desired different pharmacokinetic profile. More than two megestrol compositions can be co-administered, sequentially administered, or combined. While the first megestrol composition has a nanoparticulate particle size, the additional one or more megestrol compositions can be nanoparticulate, solubilized, or have a conventional microparticulate particle size. For example, a first megestrol composition can have a nanoparticulate particle size, conferring a short Tmax and typically a higher Cmax. This first megestrol composition can be combined, co-administered, or sequentially administered with a second composition comprising: (1) megestrol having a larger (but still nanoparticulate as defined herein) particle size, and therefore exhibiting slower absorption, a longer Tmax, and typically a lower Cmax; or (2) a microparticulate or solubilized megestrol composition, exhibiting a longer Tmax, and typically a lower Cmax. The second, third, fourth, etc., megestrol compositions can differ from the first, and from each other, for example: (1) in the effective average particle sizes of megestrol; or (2) in the dosage of megestrol. Such a combination composition can reduce the dose frequency required. If the second megestrol composition has a nanoparticulate particle size, then preferably the megestrol particles of the second composition have at least one surface stabilizer associated with the surface of the drug particles. The one or more surface stabilizers can be the same as or different from the surface stabilizer(s) present in the first megestrol composition. Preferably where co-administration of a “fast-acting” formulation and a “longer-lasting” formulation is desired, the two formulations are combined within a single composition, for example a dual-release composition. 9. Combination Active Agent Compositions The invention encompasses the nanoparticulate megestrol compositions of the invention formulated or co-administered with one or more non-megestrol active agents, which are either conventional (solubilized or microparticulate) or nanoparticulate. Methods of using such combination compositions are also encompassed by the invention. The non-megestrol active agents can be present in a crystalline phase, an amorphous phase, a semi-crystalline phase, a semi-amorphous phase, or a mixture thereof. The compound to be administered in combination with a nanoparticulate megestrol composition of the invention can be formulated separately from the nanoparticulate megestrol composition or co-formulated with the nanoparticulate megestrol composition. Where a nanoparticulate megestrol composition is co-formulated with a second active agent, the second active agent can be formulated in any suitable manner, such as immediate-release, rapid-onset, sustained-release, or dual-release form. If the non-megestrol active agent has a nanoparticulate particle size i.e., a particle size of less than about 2 microns, then preferably it will have one or more surface stabilizers associated with the surface of the active agent. In addition, if the active agent has a nanoparticulate particle size, then it is preferably poorly soluble and dispersible in at least one liquid dispersion media. By “poorly soluble” it is meant that the active agent has a solubility in a liquid dispersion media of less than about 30 mg/mL, less than about 20 mg/mL, less than about 10 mg/mL, or less than about 1 mg/mL. Useful liquid dispersion medias include, but are not limited to, water, aqueous salt solutions, safflower oil, and solvents such as ethanol, t-butanol, hexane, and glycol. Such non-megestrol active agents can be, for example, a therapeutic agent. A therapeutic agent can be a pharmaceutical agent, including biologics. The active agent can be selected from a variety of known classes of drugs, including, for example, amino acids, proteins, peptides, nucleotides, anti-obesity drugs, central nervous system stimulants, carotenoids, corticosteroids, elastase inhibitors, anti-fungals, oncology therapies, anti-emetics, analgesics, cardiovascular agents, anti-inflammatory agents, such as NSAIDs and COX-2 inhibitors, anthelmintics, anti-arrhythmic agents, antibiotics (including penicillins), anticoagulants, antidepressants, antidiabetic agents, antiepileptics, antihistamines, antihypertensive agents, antimuscarinic agents, antimycobacterial agents, antineoplastic agents, immunosuppressants, antithyroid agents, antiviral agents, anxiolytics, sedatives (hypnotics and neuroleptics), astringents, alpha-adrenergic receptor blocking agents, beta-adrenoceptor blocking agents, blood products and substitutes, cardiac inotropic agents, contrast media, corticosteroids, cough suppressants (expectorants and mucolytics), diagnostic agents, diagnostic imaging agents, diuretics, dopaminergics (antiparkinsonian agents), haemostatics, immunological agents, lipid regulating agents, muscle relaxants, parasympathomimetics, parathyroid calcitonin and biphosphonates, prostaglandins, radio-pharmaceuticals, sex hormones (including steroids), anti-allergic agents, stimulants and anoretics, sympathomimetics, thyroid agents, vasodilators, and xanthines. A description of these classes of active agents and a listing of species within each class can be found in Martindale's The Extra Pharmacopoeia, 31st Edition (The Pharmaceutical Press, London, 1996), specifically incorporated by reference. The active agents are commercially available and/or can be prepared by techniques known in the art. Exemplary nutraceuticals and dietary supplements are disclosed, for example, in Roberts et al., Nutraceuticals: The Complete Encyclopedia of Supplements, Herbs, Vitamins, and Healing Foods (American Nutraceutical Association, 2001), which is specifically incorporated by reference. Dietary supplements and nutraceuticals are also disclosed in Physicians' Desk Reference for Nutritional Supplements, 1 st Ed. (2001) and The Physicians' Desk Reference for Herbal Medicines, 1st Ed. (2001), both of which are also incorporated by reference. A nutraceutical or dietary supplement, also known as a phytochemical or functional food, is generally any one of a class of dietary supplements, vitamins, minerals, herbs, or healing foods that have medical or pharmaceutical effects on the body. Exemplary nutraceuticals or dietary supplements include, but are not limited to, lutein, folic acid, fatty acids (e.g., DHA and ARA), fruit and vegetable extracts, vitamin and mineral supplements, phosphatidylserine, lipoic acid, melatonin, glucosamine/chondroitin, Aloe Vera, Guggul, glutamine, amino acids (e.g., arginine, isoleucine, leucine, lysine, methionine, phenylanine, threonine, tryptophan, and valine), green tea, lycopene, whole foods, food additives, herbs, phytonutrients, antioxidants, flavonoid constituents of fruits, evening primrose oil, flax seeds, fish and marine animal oils, and probiotics. Nutraceuticals and dietary supplements also include bio-engineered foods genetically engineered to have a desired property, also known as “pharmafoods.” 10. Sterile Filtered Nanoparticulate Megestrol Compositions The nanoparticulate megestrol compositions of the invention can be sterile filtered. This obviates the need for heat sterilization, which can harm or degrade megestrol, as well as result in crystal growth and particle aggregation. Sterile filtration can be difficult because of the required small particle size of the composition. Filtration is an effective method for sterilizing homogeneous solutions when the membrane filter pore size is less than or equal to about 0.2 microns (200 nm) because a 0.2 micron filter is sufficient to remove essentially all bacteria. Sterile filtration is normally not used to sterilize conventional suspensions of micron-sized megestrol because the megestrol particles are too large to pass through the membrane pores. A sterile nanoparticulate megestrol dosage form is particularly useful in treating immunocompromised patients, infants or juvenile patients, and the elderly, as these patient groups are the most susceptible to infection caused by a non-sterile liquid dosage form. Because the nanoparticulate megestrol compositions of the invention can be sterile filtered, and because the compositions can have a very small megestrol effective average particle size, the compositions are suitable for parenteral administration. 11. Miscellaneous Benefits of the Nanoparticulate Megestrol Compositions of the Invention The nanoparticulate megestrol compositions preferably exhibit an increased rate of dissolution as compared to conventional microcrystalline forms of megestrol. In addition, the compositions of the invention exhibit improved performance characteristics for oral, intravenous, subcutaneous, or intramuscular injection, such as higher dose loading and smaller tablet or liquid dose volumes. Moreover, the nanoparticulate megestrol compositions of the invention do not require organic solvents or pH extremes. Another benefit of the nanoparticulate megestrol compositions of the invention is that is was surprisingly discovered that upon administration, nanoparticulate compositions of megestrol acetate reach therapeutic blood levels within one dose. This is in dramatic contrast to the current commercially available megestrol acetate composition (Megace® by Bristol Myers Squibb Co.), which requires multiple doses, administered over several days to a week, to build up to a therapeutic level of drug in the blood stream. B. Compositions The invention provides compositions comprising nanoparticulate megestrol particles and preferably at least one surface stabilizer. The one or more surface stabilizers are preferably associated with the surface of the megestrol particles. Surface stabilizers useful herein preferably do not chemically react with the megestrol particles or itself. Individual molecules of the surface stabilizer are essentially free of intermolecular cross-linkages. The present invention also includes nanoparticulate megestrol compositions together with one or more non-toxic physiologically acceptable carriers, adjuvants, or vehicles, collectively referred to as carriers. The compositions can be formulated for parenteral injection (e.g., intravenous, intramuscular, or subcutaneous), oral administration in solid, liquid, or aerosol form, vaginal, nasal, rectal, ocular, local (powders, ointments or drops), buccal, intracisternal, intraperitoneal, or topical administration, and the like. 1. Megestrol Particles As used herein the term megestrol, which is the active ingredient in the composition, is used to mean megestrol, megestrol acetate (17α-acetyloxy-6-methylpregna-4,6-diene-3,20-dione), or a salt thereof. The megestrol particles can be present in a crystalline phase, an amorphous phase, a semi-crystalline phase, a semi-amorphous phase, or a mixture thereof. Megestrol acetate is well known in the art and is readily recognized by one of ordinary skill. Generally, megestrol is used for treating breast cancer, endometrial cancer and, less frequently, prostate cancer. Megestrol is also frequently used as an appetite stimulant for patients in a wasting state, such as HIV wasting, cancer wasting, and anorexia. Megestrol may be used for other indications where progestins are typically used, such as hormone replacement therapy in post-menopausal women and oral contraception. Further, megestrol may be used for ovarian suppression in several conditions such as endometriosis, hirsutism, dysmenorrhea, and uterine bleeding, as well as uterine cancer, cervical cancer, and renal cancer. Megestrol is also used in patients following castration. 2. Surface Stabilizers The choice of a surface stabilizer for megestrol is non-trivial. Accordingly, the present invention is directed to the surprising discovery that nanoparticulate megestrol compositions can be made. Combinations of more than one surface stabilizer can be used in the invention. Preferred surface stabilizers include, but are not limited to, hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, random copolymers of vinyl pyrrolidone and vinyl acetate, sodium lauryl sulfate, dioctylsulfosuccinate or a combination thereof. Preferred primary surface stabilizers include, but are not limited to, hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, random copolymers of vinyl pyrrolidone and vinyl acetate, or a combination thereof. Preferred secondary surface stabilizers include, but are not limited to, sodium lauryl sulfate and dioctylsulfosuccinate. Other surface stabilizers which can be employed in the invention include, but are not limited to, known organic and inorganic pharmaceutical excipients. Such excipients include various polymers, low molecular weight oligomers, natural products, and surfactants. Surface stabilizers include nonionic, cationic, ionic, and zwitterionic surfactants. Representative examples of surface stabilizers include hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, sodium lauryl sulfate, dioctylsulfosuccinate, gelatin, casein, lecithin (phosphatides), dextran, gum acacia, cholesterol, tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glycerol monostearate, cetostearyl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers (e.g., macrogol ethers such as cetomacrogol 1000), polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters (e.g., the commercially available Tweens® such as e.g., Tween 20® and Tween 80® (ICI Specialty Chemicals)); polyethylene glycols (e.g., Carbowaxs 3550® and 934® (Union Carbide)), polyoxyethylene stearates, colloidal silicon dioxide, phosphates, carboxymethylcellulose calcium, carboxymethylcellulose sodium, methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose phthalate, noncrystalline cellulose, magnesium aluminium silicate, triethanolamine, polyvinyl alcohol (PVA), 4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide and formaldehyde (also known as tyloxapol, superione, and triton), poloxamers (e.g., Pluronics F68® and F108®, which are block copolymers of ethylene oxide and propylene oxide); poloxamines (e.g., Tetronic 908®, also known as Poloxamine 908®, which is a tetrafunctional block copolymer derived from sequential addition of propylene oxide and ethylene oxide to ethylenediamine (BASF Wyandotte Corporation, Parsippany, N.J.)); Tetronic 1508® (T-1508) (BASF Wyandotte Corporation), Tritons X-200®, which is an alkyl aryl polyether sulfonate (Rohm and Haas); Crodestas F-100®, which is a mixture of sucrose stearate and sucrose distearate (Croda Inc.); p-isononylphenoxypoly-(glycidol), also known as Olin-10G® or Surfactant 10-G® (Olin Chemicals, Stamford, Conn.); Crodestas SL-40® (Croda, Inc.); and SA9OHCO, which is C18H37CH2(CON(CH3)—CH2(CHOH)4(CH2OH)2 (Eastman Kodak Co.); decanoyl-N-methylglucamide; n-decyl β-D-glucopyranoside; n-decyl β-D-maltopyranoside; n-dodecyl β-D-glucopyranoside; n-dodecyl β-D-maltoside; heptanoyl-N-methylglucamide; n-heptyl-β-D-glucopyranoside; n-heptyl β-D-thioglucoside; n-hexyl β-D-glucopyranoside; nonanoyl-N-methylglucamide; n-noyl β-D-glucopyranoside; octanoyl-N-methylglucamide; n-octyl-β-D-glucopyranoside; octyl β-D-thioglucopyranoside; PEG-phospholipid, PEG-cholesterol, PEG-cholesterol derivative, PEG-vitamin A, PEG-vitamin E, lysozyme, random copolymers of vinyl pyrrolidone and vinyl acetate, and the like. Examples of useful cationic surface stabilizers include, but are not limited to, polymers, biopolymers, polysaccharides, cellulosics, alginates, phospholipids, and nonpolymeric compounds, such as zwitterionic stabilizers, poly-n-methylpyridinium, anthryul pyridinium chloride, cationic phospholipids, chitosan, polylysine, polyvinylimidazole, polybrene, polymethylmethacrylate trimethylammoniumbromide bromide (PMMTMABr), hexyldesyltrimethylammonium bromide (HDMAB), and polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate. Other useful cationic stabilizers include, but are not limited to, cationic lipids, sulfonium, phosphonium, and quarternary ammonium compounds, such as stearyltrimethylammonium chloride, benzyl-di(2-chloroethyl)ethylammonium bromide, coconut trimethyl ammonium chloride or bromide, coconut methyl dihydroxyethyl ammonium chloride or bromide, decyl triethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride or bromide, C12-15dimethyl hydroxyethyl ammonium chloride or bromide, coconut dimethyl hydroxyethyl ammonium chloride or bromide, myristyl trimethyl ammonium methyl sulphate, lauryl dimethyl benzyl ammonium chloride or bromide, lauryl dimethyl (ethenoxy)4 ammonium chloride or bromide, N-alkyl (C12-18)dimethylbenzyl ammonium chloride, N-alkyl (C14-18)dimethyl-benzyl ammonium chloride, N-tetradecylidmethylbenzyl ammonium chloride monohydrate, dimethyl didecyl ammonium chloride, N-alkyl and (C12-14) dimethyl 1-napthylmethyl ammonium chloride, trimethylammonium halide, alkyl-trimethylammonium salts and dialkyl-dimethylammonium salts, lauryl trimethyl ammonium chloride, ethoxylated alkyamidoalkyldialkylammonium salt and/or an ethoxylated trialkyl ammonium salt, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium, chloride monohydrate, N-alkyl(C12-14) dimethyl 1-naphthylmethyl ammonium chloride and dodecyldimethylbenzyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, C12, C15, C17 trimethyl ammonium bromides, dodecylbenzyl triethyl ammonium chloride, poly-diallyldimethylammonium chloride (DADMAC), dimethyl ammonium chlorides, alkyldimethylammonium halogenides, tricetyl methyl ammonium chloride, decyltrimethylammonium bromide, dodecyltriethylammonium bromide, tetradecyltrimethylammonium bromide, methyl trioctylammonium chloride (ALIQUAT 336™), POLYQUAT 10™, tetrabutylammonium bromide, benzyl trimethylammonium bromide, choline esters (such as choline esters of fatty acids), benzalkonium chloride, stearalkonium chloride compounds (such as stearyltrimonium chloride and Di-stearyldimonium chloride), cetyl pyridinium bromide or chloride, halide salts of quaternized polyoxyethylalkylamines, MIRAPOL™ and ALKAQUAT™ (Alkaril Chemical Company), alkyl pyridinium salts; amines, such as alkylamines, dialkylamines, alkanolamines, polyethylenepolyamines, N,N-dialkylaminoalkyl acrylates, and vinyl pyridine, amine salts, such as lauryl amine acetate, stearyl amine acetate, alkylpyridinium salt, and alkylimidazolium salt, and amine oxides; imide azolinium salts; protonated quaternary acrylamides; methylated quaternary polymers, such as poly[diallyl dimethylammonium chloride] and poly-[N-methyl vinyl pyridinium chloride]; and cationic guar. Such exemplary cationic surface stabilizers and other useful cationic surface stabilizers are described in J. Cross and E. Singer, Cationic Surfactants: Analytical and Biological Evaluation (Marcel Dekker, 1994); P. and D. Rubingh (Editor), Cationic Surfactants: Physical Chemistry (Marcel Dekker, 1991); and J. Richmond, Cationic Surfactants: Organic Chemistry, (Marcel Dekker, 1990). Particularly preferred nonpolymeric primary stabilizers are any nonpolymeric compound, such benzalkonium chloride, a carbonium compound, a phosphonium compound, an oxonium compound, a halonium compound, a cationic organometallic compound, a quarternary phosphorous compound, a pyridinium compound, an anilinium compound, an ammonium compound, a hydroxylammonium compound, a primary ammonium compound, a secondary ammonium compound, a tertiary ammonium compound, and quarternary ammonium compounds of the formula NR1R2R3R4(+). For compounds of the formula NR1R2R3R4(+): (i) none of R1-R4 are CH3; (ii) one of R1-R4 is CH3; (iii) three of R1-R4 are CH3; (iv) all of R1-R4 are CH3; (v) two of R1-R4 are CH3, one of R1-R4 is C6H5CH2, and one of R1-R4 is an alkyl chain of seven carbon atoms or less; (vi) two of R1-R4 are CH3, one of R1-R4 is C6H5CH2, and one of R1-R4 is an alkyl chain of nineteen carbon atoms or more; (vii) two of R1-R4 are CH3 and one of R1-R4 is the group C6H5(CH2)n, where n>1; (viii) two of R1-R4 are CH3, one of R—R4 is C6H5CH2, and one of R1-R4 comprises at least one heteroatom; (ix) two of R1-R4 are CH3, one of R—R4 is C6H5CH2, and one of R1-R4 comprises at least one halogen; (x) two of R1-R4 are CH3, one of R—R4 is C6H5CH2, and one of R1-R4 comprises at least one cyclic fragment; (xi) two of R1-R4 are CH3 and one of R—R4 is a phenyl ring; or (xii) two of R1-R4 are CH3 and two of R1-R4 are purely aliphatic fragments. Such compounds include, but are not limited to, behenalkonium chloride, benzethonium chloride, cetylpyridinium chloride, behentrimonium chloride, lauralkonium chloride, cetalkonium chloride, cetrimonium bromide, cetrimonium chloride, cethylamine hydrofluoride, chlorallylmethenamine chloride (Quaternium-15), distearyldimonium chloride (Quaternium-5), dodecyl dimethyl ethylbenzyl ammonium chloride (Quaternium-14), Quaternium-22, Quaternium-26, Quaternium-18 hectorite, dimethylaminoethylchloride hydrochloride, cysteine hydrochloride, diethanolammonium POE (10) oletyl ether phosphate, diethanolammonium POE (3)oleyl ether phosphate, tallow alkonium chloride, dimethyl dioctadecylammoniumbentonite, stearalkonium chloride, domiphen bromide, denatonium benzoate, myristalkonium chloride, laurtrimonium chloride, ethylenediamine dihydrochloride, guanidine hydrochloride, pyridoxine HCl, iofetamine hydrochloride, meglumine hydrochloride, methylbenzethonium chloride, myrtrimonium bromide, oleyltrimonium chloride, polyquaternium-1, procainehydrochloride, cocobetaine, stearalkonium bentonite, stearalkoniumhectonite, stearyl trihydroxyethyl propylenediamine dihydrofluoride, tallowtrimonium chloride, and hexadecyltrimethyl ammonium bromide. Most of these surface stabilizers are known pharmaceutical excipients and are described in detail in the Handbook of Pharmaceutical Excipients, published jointly by the American Pharmaceutical Association and The Pharmaceutical Society of Great Britain (The Pharmaceutical Press, 2000), specifically incorporated by reference. The surface stabilizers are commercially available and/or can be prepared by techniques known in the art. 3. Other Pharmaceutical Excipients Pharmaceutical megestrol compositions according to the invention may also comprise one or more binding agents, filling agents, lubricating agents, suspending agents, sweeteners, flavoring agents, preservatives, buffers, wetting agents, disintegrants, effervescent agents, and other excipients. Such excipients are known in the art. Examples of filling agents are lactose monohydrate, lactose anhydrous, and various starches; examples of binding agents are various celluloses and cross-linked polyvinylpyrrolidone, microcrystalline cellulose, such as Avicel® PH101 and Avicel® PH102, microcrystalline cellulose, and silicified microcrystalline cellulose (ProSolv SMCC™). Suitable lubricants, including agents that act on the flowability of the powder to be compressed, are colloidal silicon dioxide, such as Aerosil® 200, talc, stearic acid, magnesium stearate, calcium stearate, and silica gel. Examples of sweeteners are any natural or artificial sweetener, such as sucrose, xylitol, sodium saccharin, cyclamate, aspartame, and acsulfame. Examples of flavoring agents are Magnasweet® (trademark of MAFCO), bubble gum flavor, and fruit flavors, and the like. Examples of preservatives are potassium sorbate, methylparaben, propylparaben, benzoic acid and its salts, other esters of parahydroxybenzoic acid such as butylparaben, alcohols such as ethyl or benzyl alcohol, phenolic compounds such as phenol, or quarternary compounds such as benzalkonium chloride. Suitable diluents include pharmaceutically acceptable inert fillers, such as microcrystalline cellulose, lactose, dibasic calcium phosphate, saccharides, and/or mixtures of any of the foregoing. Examples of diluents include microcrystalline cellulose, such as Avicel® PH101 and Avicel® PH1 02; lactose such as lactose monohydrate, lactose anhydrous, and Pharmatose® DCL21; dibasic calcium phosphate such as Emcompress®; mannitol; starch; sorbitol; sucrose; and glucose. Suitable disintegrants include lightly crosslinked polyvinyl pyrrolidone, corn starch, potato starch, maize starch, and modified starches, croscarmellose sodium, cross-povidone, sodium starch glycolate, and mixtures thereof. Examples of effervescent agents are effervescent couples such as an organic acid and a carbonate or bicarbonate. Suitable organic acids include, for example, citric, tartaric, malic, fumaric, adipic, succinic, and alginic acids and anhydrides and acid salts. Suitable carbonates and bicarbonates include, for example, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, sodium glycine carbonate, L-lysine carbonate, and arginine carbonate. Alternatively, only the sodium bicarbonate component of the effervescent couple may be present. 4. Nanoparticulate Megestrol or Active Agent Particle Size As used herein, particle size is determined on the basis of the weight average particle size as measured by conventional particle size measuring techniques well known to those skilled in the art. Such techniques include, for example, sedimentation field flow fractionation, photon correlation spectroscopy, light scattering, and disk centrifugation. The compositions of the invention comprise nanoparticulate megestrol particles which have an effective average particle size of less than about 2000 nm (i.e., 2 microns). In other embodiments of the invention, the megestrol particles have an effective average particle size of less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 nm, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 150 nm, less than about 100 nm, less than about 75 nm, or less than about 50 nm, when measured by the above techniques. If the nanoparticulate megestrol composition additionally comprises one or more non-megestrol nanoparticulate active agents, then such active agents have an effective average particle size of less than about 2000 nm (i.e., 2 microns). In other embodiments of the invention, the nanoparticulate non-megestrol active agents can have an effective average particle size of less than about 1900 nm, less than about 1800 nm, less than about 1700 nm, less than about 1600 nm, less than about 1500 nm, less than about 1400 run, less than about 1300 nm, less than about 1200 nm, less than about 1100 nm, less than about 1000 nm, less than about 900 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 150 nm, less than about 100 nm, less than about 75 nm, or less than about 50 nm, as measured by light-scattering methods, microscopy, or other appropriate methods. By “an effective average particle size of less than about 2000 nm” it is meant that at least 50% of the nanoparticulate megestrol or nanoparticulate non-megestrol active agent particles have a particle size of less than about 2000 nm, by weight, when measured by the above-noted techniques. Preferably, at least about 70%, about 90%, about 95%, or about 99% of the nanoparticulate megestrol or nanoparticulate non-megestrol active agent particles have a particle size of less than the effective average, i.e., less than about 2000 mm, less than about 1900 nm, less than about 1800 nm, etc. If the nanoparticulate megestrol composition is combined with a conventional or microparticulate megestrol composition or non-megestrol active agent composition, then such a composition is either solubilized or has an effective average particle size of greater than about 2 microns. By “an effective average particle size of greater than about 2 microns” it is meant that at least 50% of the conventional megestrol or non-megestrol active agent particles have a particle size of greater than about 2 microns, by weight, when measured by the above-noted techniques. In other embodiments of the invention, at least about 70%, about 90%, about 95%, or about 99% of the conventional megestrol or non-megestrol active agent particles have a particle size greater than about 2 microns. 5. Concentration of Nanoparticulate Megestrol and Surface Stabilizers The relative amounts of nanoparticulate megestrol and one or more surface stabilizers can vary widely. The optimal amount of the individual components can depend, for example, the hydrophilic lipophilic balance (HLB), melting point, and the surface tension of water solutions of the stabilizer, etc. The concentration of megestrol can vary from about 99.5% to about 0.001%, from about 95% to about 0.1%, or from about 90% to about 0.5%, by weight, based on the total combined dry weight of the megestrol and at least one surface stabilizer, not including other excipients. The concentration of the at least one surface stabilizer can vary from about 0.5% to about 99.999%, from about 5.0% to about 99.9%, or from about 10% to about 99.5%, by weight, based on the total combined dry weight of the megestrol and at least one surface stabilizer, not including other excipients. If a combination of two or more surface stabilizers is employed in the composition, the concentration of the at least one primary surface stabilizer can vary from about 0.01% to about 99.5%, from about 0.1% to about 95%, or from about 0.5% to about 90%, by weight, based on the total combined dry weight of the megestrol, at least one primary surface stabilizer, and at least one secondary surface stabilizer, not including other excipients. In addition, the concentration of the at least one secondary surface stabilizer can vary from about 0.01% to about 99.5%, from about 0.1% to about 95%, or from about 0.5% to about 90%, by weight, based on the total combined dry weight of the megestrol, at least one primary surface stabilizer, and at least one secondary surface stabilizer, not including other excipients. C. Methods of Making Nanoparticulate Megestrol Compositions The nanoparticulate megestrol compositions can be made using, for example, milling, homogenization, or precipitation techniques. Exemplary methods of making nanoparticulate compositions are described in the '684 patent. Methods of making nanoparticulate compositions are also described in U.S. Pat. No. 5,518,187 for “Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,718,388 for “Continuous Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,862,999 for “Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,665,331 for “Co-Microprecipitation of Nanoparticulate Pharmaceutical Agents with Crystal Growth Modifiers;” U.S. Pat. No. 5,662,883 for “Co-Microprecipitation of Nanoparticulate Pharmaceutical Agents with Crystal Growth Modifiers;” U.S. Pat. No. 5,560,932 for “Microprecipitation of Nanoparticulate Pharmaceutical Agents;” U.S. Pat. No. 5,543,133 for “Process of Preparing X-Ray Contrast Compositions Containing Nanoparticles;” U.S. Pat. No. 5,534,270 for “Method of Preparing Stable Drug Nanoparticles;” U.S. Pat. No. 5,510,118 for “Process of Preparing Therapeutic Compositions Containing Nanoparticles;” and U.S. Pat. No. 5,470,583 for “Method of Preparing Nanoparticle Compositions Containing Charged Phospholipids to Reduce Aggregation,” all of which are specifically incorporated by reference. The resultant nanoparticulate megestrol compositions can be utilized in solid or liquid dosage formulations, such as controlled release formulations, solid dose fast melt formulations, aerosol formulations, lyophilized formulations, tablets, capsules, etc. 1. Milling to Obtain Nanoparticulate Megestrol Dispersions Milling megestrol to obtain a nanoparticulate megestrol dispersion comprises dispersing megestrol particles in a liquid dispersion medium in which megestrol is poorly soluble, followed by applying mechanical means in the presence of grinding media to reduce the particle size of megestrol to the desired effective average particle size. The dispersion medium can be, for example, water, safflower oil, ethanol, t-butanol, glycerin, polyethylene glycol (PEG), hexane, or glycol. The megestrol particles can be reduced in size in the presence of at least one surface stabilizer. Alternatively, the megestrol particles can be contacted with one or more surface stabilizers after attrition. Other compounds, such as a diluent, can be added to the megestrol/surface stabilizer composition either before, during, or after the size reduction process. Dispersions can be manufactured continuously or in a batch mode. 2. Precipitation to Obtain Nanoparticulate Megestrol Compositions Another method of forming the desired nanoparticulate megestrol composition is by microprecipitation. This is a method of preparing stable dispersions of poorly soluble active agents in the presence of one or more surface stabilizers and one or more colloid stability enhancing surface active agents free of any trace toxic solvents or solubilized heavy metal impurities. Such a method comprises, for example: (1) dissolving megestrol in a suitable solvent; (2) adding the formulation from step (1) to a solution comprising at least one surface stabilizer; and (3) precipitating the formulation from step (2) using an appropriate non-solvent. The method can be followed by removal of any formed salt, if present, by dialysis or diafiltration and concentration of the dispersion by conventional means. 3. Homogenization to Obtain Nanoparticulate Megestrol Compositions Exemplary homogenization methods of preparing nanoparticulate active agent compositions are described in U.S. Pat. No. 5,510,118, for “Process of Preparing Therapeutic Compositions Containing Nanoparticles.” Such a method comprises dispersing megestrol particles in a liquid dispersion medium, followed by subjecting the dispersion to homogenization to reduce the particle size of the megestrol to the desired effective average particle size. The megestrol particles can be reduced in size in the presence of at least one surface stabilizer. Alternatively, the megestrol particles can be contacted with one or more surface stabilizers either before or after attrition. Other compounds, such as a diluent, can be added to the megestrol/surface stabilizer composition either before, during, or after the size reduction process. Dispersions can be manufactured continuously or in a batch mode. D. Methods of Using Nanoparticulate Megestrol Formulations of the Invention 1. Applications of the Nanoparticulate Compositions of the Invention The nanoparticulate megestrol compositions of the invention may be used as an appetite stimulant to treat wasting conditions or cachexia. As used herein, the term “wasting” is used to mean a condition where the patient is losing body mass as a side effect of a disease progression, a disease treatment, or other condition. Examples of conditions where wasting is prevalent include, but are not limited to, HIV or AIDS, cancer, cachexia and anorexia. Additional conditions where the nanoparticulate megestrol compositions of the invention may be used include, but are not limited to, neoplastic diseases where the disease normally regresses or the patient's symptoms are normally reduced in response to megestrol, or any other progestin. The nanoparticulate megestrol compositions of the invention may also be used to treat conditions such as breast cancer, endometrial cancer, uterine cancer, cervical cancer, prostate cancer, and renal cancer. As used herein, the term “cancer” is used as one of ordinary skill in the art would recognize the term. Examples of cancers include, but are not limited to, neoplasias (or neoplasms), hyperplasias, dysplasias, metaplasias, and hypertrophies. The neoplasms may be benign or malignant, and they may originate from any cell type, including but not limited to epithelial cells of various origin, muscle cells, and endothelial cells. The present invention also provides methods of hormone replacement therapy in post-menopausal women, or in subjects after castration, comprising administering a nanoparticulate megestrol composition of the invention. Further, the compositions of the present invention may be used for ovarian suppression in several situations such as endometriosis, hirsutism, dysmenorrhea, and uterine bleeding. The present invention also provides methods of oral contraception comprising administering a nanoparticulate megestrol composition of the invention. In one embodiment, the compositions of the invention are administered in combination with estrogen or a synthetic estrogen. 2. Dosage Forms of the Invention The nanoparticulate megestrol compositions of the invention can be administered to a subject via any conventional means including, but not limited to, orally, rectally, ocularly, parenterally (e.g., intravenous, intramuscular, or subcutaneous), intracisternally, pulmonary, intravaginally, intraperitoneally, locally (e.g., powders, ointments or drops), or as a buccal or nasal spray. As used herein, the term “subject” is used to mean an animal, preferably a mammal, including a human or non-human. The terms patient and subject may be used interchangeably. Moreover, the nanoparticulate megestrol compositions of the invention can be formulated into any suitable dosage form, including but not limited to liquid dispersions, gels, aerosols, ointments, creams, controlled release formulations, fast melt formulations, lyophilized formulations, tablets, capsules, delayed release formulations, extended release formulations, pulsatile release formulations, and mixed immediate release and controlled release formulations. Nanoparticulate megestrol compositions suitable for parenteral injection may comprise physiologically acceptable sterile aqueous or nonaqueous solutions, dispersions, suspensions or emulsions, and sterile powders for reconstitution into sterile injectable solutions or dispersions. Examples of suitable aqueous and nonaqueous carriers, diluents, solvents, or vehicles including water, ethanol, polyols (propyleneglycol, polyethylene-glycol, glycerol, and the like), suitable mixtures thereof, vegetable oils (such as olive oil) and injectable organic esters such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants. The nanoparticulate megestrol compositions may also contain adjuvants such as preserving, wetting, emulsifying, and dispensing agents. Prevention of the growth of microorganisms can be ensured by various antibacterial and antifungal agents, such as parabens, chlorobutanol, phenol, sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the use of agents delaying absorption, such as aluminum monostearate and gelatin. Solid dosage forms for oral administration include, but are not limited to, capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active agent is admixed with at least one of the following: (a) one or more inert excipients (or carriers), such as sodium citrate or dicalcium phosphate; (b) fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and silicic acid; (c) binders, such as carboxymethylcellulose, alignates, gelatin, polyvinylpyrrolidone, sucrose, and acacia; (d) humectants, such as glycerol; (e) disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain complex silicates, and sodium carbonate; (f) solution retarders, such as paraffin; (g) absorption accelerators, such as quaternary ammonium compounds; (h) wetting agents, such as cetyl alcohol and glycerol monostearate; (i) adsorbents, such as kaolin and bentonite; and (j) lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, or mixtures thereof. For capsules, tablets, and pills, the dosage forms may also comprise buffering agents. Liquid nanoparticulate megestrol dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups, and elixirs. In addition to megestrol, the liquid dosage forms may comprise inert diluents commonly used in the art, such as water or other solvents, solubilizing agents, and emulsifiers. Exemplary emulsifiers are ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propyleneglycol, 1,3-butyleneglycol, dimethylformamide, oils, such as cottonseed oil, groundnut oil, corn germ oil, olive oil, castor oil, and sesame oil, glycerol, tetrahydrofurfuryl alcohol, polyethyleneglycols, fatty acid esters of sorbitan, or mixtures of these substances, and the like. Besides such inert diluents, the composition can also include adjuvants, such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents. 3. Dosage Quantities for the Nanoparticulate Megestrol Compositions of the Invention The present invention provides a method of achieving therapeutically effective plasma levels of megestrol in a subject at a lower dose than the standard commercial formulations. This can permit smaller dosing volumes depending on the megestrol concentration chosen. Such a method comprises orally administering to a subject an effective amount of a nanoparticulate megestrol composition. The nanoparticulate megestrol composition, when tested in fasting subjects in accordance with standard pharmacokinetic practice, produces a maximum blood plasma concentration profile of megestrol of greater than about 30 ng/ml in less than about 5 hours after the initial dose of the composition. As used herein, the phrase “maximum plasma concentration” is interpreted as the maximum plasma concentration that megestrol will reach in fasting subjects. A suitable dose of megestrol, administered according to the method of the invention, is typically in the range of about 1 mg/day to about 1000 mg/day, or from about 40 mg/day to about 800 mg/day. Preferably, the therapeutically effective amount of the megestrol of this invention is about ⅙, about ⅕, about ¼, about ⅓rd, or about ½ of the therapeutically effective amount of existing commercial megestrol formulations, e.g., Megace®. “Therapeutically effective amount” as used herein with respect to a drug dosage, shall mean that dosage that provides the specific pharmacological response for which the drug is administered in a significant number of subjects in need of such treatment. It is emphasized that “therapeutically effective amount,” administered to a particular subject in a particular instance will not always be effective in treating the diseases described herein, even though such dosage is deemed a “therapeutically effective amount” by those skilled in the art. It is to be further understood that drug dosages are, in particular instances, measured as oral dosages, or with reference to drug levels as measured in blood. One of ordinary skill will appreciate that effective amounts of megestrol can be determined empirically and can be employed in pure form or, where such forms exist, in pharmaceutically acceptable salt, ester, or prodrug form. Actual dosage levels of megestrol in the nanoparticulate compositions of the invention may be varied to obtain an amount of megestrol that is effective to obtain a desired therapeutic response for a particular composition and method of administration. The selected dosage level therefore depends upon the desired therapeutic effect, the route of administration, the potency of the administered megestrol, the desired duration of treatment, and other factors. Dosage unit compositions may contain such amounts of such submultiples thereof as may be used to make up the daily dose. It will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors: the type and degree of the cellular or physiological response to be achieved; activity of the specific agent or composition employed; the specific agents or composition employed; the age, body weight, general health, sex, and diet of the patient; the time of administration, route of administration, and rate of excretion of the agent; the duration of the treatment; drugs used in combination or coincidental with the specific agent; and like factors well known in the medical arts. The following examples are given to illustrate the present invention. It should be understood, however, that the invention is not to be limited to the specific conditions or details described in these examples. Throughout the specification, any and all references to a publicly available document, including a U.S. patent, are specifically incorporated by reference. In the examples that follow, the value for D50 is the particle size below which 50% of the megestrol particles fall. Similarly, D90 is the particle size below which 90% of the megestrol particles fall. The formulations in the examples that follow were also investigated using a light microscope. Here, “stable” nanoparticulate dispersions (uniform Brownian motion) were readily distinguishable from “aggregated” dispersions (relatively large, nonuniform particles without motion). Stable, as known in the art and used herein, means the particles don't substantially aggregate or ripen (increase in fundamental particle size). EXAMPLE 1 The purpose of this example was to describe preparation of nanoparticulate dispersions of megestrol acetate. Formulations 1, 2, 3, 4 and 5, shown in Table 1, were milled under high energy milling conditions using a NanoMill® (Elan Drug Delivery, Inc.) (see e.g., WO 00/72973 for “Small-Scale Mill and Method Thereof”) and a Dyno®-Mill (Willy Bachofen AG). TABLE 1 Identity and Identity and Quantity Quantity Quantity of Primary of Secondary of Surface Surface Mean D90 Formulation Megestrol Stabilizer Stabilizer (nm) (nm) 1 5% 1% HLPC-SL 0.05% DOSS 167 224 2 5% 1% HPMC 0.05% DOSS 156 215 3 5% 1% PVP 0.05% DOSS 167 226 4 5% 1% Plasdone ® 0.05% DOSS 164 222 S630* 5 5% 1% HPMC 0.05% SLS 148 208 *Plasdone ® S630 (ISP) is a random copolymer of vinyl acetate and vinyl pyrrolidone. Formulations 1-5 showed small, well-dispersed particles using the Horiba La-910 Laser Scattering Particle Size Distribution Analyzer (Horiba Instruments, Irvine, Calif.) and light microscopy. Formulations 1-5 were stable in electrolyte fluids and had acceptable physical stability at 5° C. for 4 weeks. Electrolyte fluids are representative of physiological conditions found in the human body. Formulations 1, 2, 3, and 4 also exhibited acceptable stability at 25° C. and 40° C. for 4 weeks. Formulation 5 exhibited acceptable stability at 40° C. for at least 3 weeks. EXAMPLE 2 This example compares the pharmacokinetic parameters of nanoparticulate megestrol acetate formulations of the present invention with conventional microparticulate formulations of megestrol acetate. Twelve male beagles, at least twelve months of age, were divided into 2 groups based on whether they were fasting or being fed. The dogs were acclimated for thirteen days prior to dosing. The animals weighed approximately 11.4 to 14.3 kg at the time of dosing, and the dose was adjusted to 10 mg/kg. Water was available ad libitum. The animals were fasted (food only) for twelve to sixteen hours prior to dosing on day 1. On day 1, each dog was administered a formulation by gavage. Following dosing, the gavage tube was flushed with 18 ml of water. In the fed study, the animals were fed a high fat meal about 1 hour prior to dosing. The dogs were subdivided into four groups, with each group receiving either Formulation A (nanoparticulate megestrol dispersion #1, comprising 4.0% megestrol acetate, 0.8% HPMC, and 0.4% DOSS), Formulation B (nanoparticulate megestrol dispersion #2, comprising 4.0% megestrol acetate, 0.8% HPMC, and 0.04% SLS), Formulation C (suspension of microparticulate megestrol acetate, Par Pharmaceutical, Inc., New York) or Formulation D (Megace® Oral Suspension, which is a suspension of microparticulate megestrol acetate). Each formulation was adjusted to administer a dose of 10 mg/kg of megestrol acetate to the subject. Prior to dosing, blood samples were taken from each subject. Blood samples were then collected from each subject at 15 and 30 minutes, as well as 1, 2, 3, 4, 6, 8, 24, 48, and 72 hours after dosing and centrifuged. Plasma was then separated and diluted when necessary, and subsequently analyzed for megestrol acetate by HPLC. Tables 2 and 3 summarize the pharmacokinetic data of the four formulations administered to fasted dogs and fed dogs, respectively. TABLE 2 Summary of Pharmacokinetic Data in Fasted Dogs Formulation A n = 3 Formulation B n = 3 Formulation C n = 3 Formulation D n = 3 Parameters (Mean ± SD) (Mean ± SD) (Mean ± SD) (Mean ± SD) AUC0-t 37774.23 ± 11648.60 21857.68 ± 10737.53 17395.95 ± 10428.73 10094.30 ± 1990.89 AUC0-inf 49408.88 ± 3392.80 27863.56 ± 15279.16 6948.48 ± * 12007.13 ± 1923.80 Cmax 2209.74 ± 351.54 1563.02 ± 787.37 484.98 ± 321.70 339.92 ± 175.86 Tmax 0.83 ± 0.29 0.50 ± 0.00 18.67 ± 9.24 2.67 ± 0.58 t1/2 42.01 ± 33.81 30.09 ± 19.37 26.57 ± * 25.59 ± 7.11 Kel 0.025 ± 0.018 0.032 ± 0.024 0.026 ± * 0.028 ± 0.007 AUC0-t (ng · hr/ml) = Area under the curve from time zero to the last measurable concentration; AUC0-inf (ng · hr/ml) = Area under the curve from time zero to infinity; Cmax (ng/ml) = Maximum plasma concentration; Tmax (hr) = Time to occurrence of Cmax; t1/2 (hr) = Apparent elimination half-life; Kel (1/hr) = elimination rate constant; * n = 1. TABLE 3 Summary of Pharmacokinetic Data in Fed Dogs Formulation A Formulation B Formulation C Formulation D n = 3 n = 3 n = 3 n = 3 Parameters (Mean ± SD) (Mean ± SD) (Mean ± SD) (Mean ± SD) AUC0-t 48543.56 ± 11608.55 36687.92 ± 12016.26 27332.11 ± 6488.79 31397.16 ± 5823.79 AUC0-inf 61734.90 ± 4918.52 42787.74 ± 14630.92 31720.98 ± 5580.32 40218.66 ± 8649.33* Cmax 3777.34 ± 2489.41 2875.82 ± 1334.32 2180.73 ± 406.28 2577.83 ± 665.31 Tmax 1.67 ± 2.02 3.00 ± 4.33 1.00 ± 0.00 0.83 ± 0.29 T1/2 34.35 ± 12.10 26.67 ± 7.80 26.16 ± 10.88 36.60 ± 9.62* Kel 0.022 ± 0.009 0.028 ± 0.010 0.31 ± 0.16 0.20 ± 0.005 AUC0-t (ng · hr/ml) = Area under the curve from time zero to the last measurable concentration; AUC0-inf (ng · hr/ml) = Area under the curve from time zero to infinity; Cmax(ng/ml) = Maximum plasma concentration; Tmax (hr) = Time to occurrence of Cmax; t1/2 (hr) = Apparent elimination half-life; Kel (1/hr) = elimination rate constant; *n = 2. The results in the fasted dogs show that the nanoparticulate megestrol formulations (Formulations A and B) showed dramatically superior bioavailability, as evidenced by the superior AUC and Cmax results, as compared to the conventional microparticulate megestrol formulations (Formulations C and D). Formulation A, with a Cmax of 2210, had a maximum concentration more than 4½ times that of Formulation C (485), and a maximum concentration more than 6½ times that of Formulation D (340). Formulation B, with a Cmax of 1563, had a maximum concentration more than 3.2 times that of Formulation C (485), and a maximum concentration more than 4.6 times that of Formulation D (340). Also, Formulation A, with an AUC of 49,409 ng hr/mL, had an oral bioavailability more than 7 times that of Formulation C (6948 ng hr/mL) and an oral bioavailability of more than 4 times that of Formulation D (12007 ng hr/mL). Formulation B, with an AUC of 27,864 ng hr/mL, had an oral bioavailability more than 4 times that of Formulation C (6949 ng hr/mL) and an oral bioavailability more than 2 times that of Formulation D (12,007 ng hr/mL). In addition, in the fasted dogs the nanoparticulate megestrol formulations (Formulations A and B) showed dramatically superior faster onset of action, as evidenced by the superior Tmax results, as compared to the conventional microparticulate megestrol formulations (Formulations C and D). Formulation A, with a Tmax of 0.83 hr, reached a maximum concentration of megestrol in less than {fraction (1/20)}th the time of Formulation C (18.67 hr), and in less than ⅓rd the time of Formulation D (2.67 hr). Formulation B, with a Tmax of 0.50 hr, reached a maximum concentration in less than {fraction (1/37)}th the time of Formulation C (18.67 hr), and in less than ⅕th the time of Formulation D (2.67 hr). Similarly, the results in the fed dogs show that the nanoparticulate megestrol formulations (Formulations A and B) showed dramatically superior bioavailability, as evidenced by the superior AUC and Cmax results, as compared to the conventional microparticulate megestrol formulations (Formulations C and D). Formulation A, with a Cmax of 3777, had a maximum concentration of about more than 1.7 times that of Formulation C (2181), and a maximum concentration of about more than 1.5 times that of Formulation D (2578). Formulation B, with a Cmax of 2876, had a maximum concentration of about more than 1.3 times that of Formulation C (2181), and a maximum concentration of about more than 1.1 times that of Formulation D (2578). Formulation A, with an AUC of 61,735 ng hr/mL, had an oral bioavailability of more than 1.9 times that of Formulation C (31721 ng hr/mL) and more than 1.5 times that of Formulation D (40219 ng hr/mL). Formulation B, with an AUC of 42788 ng hr/mL, had an oral bioavailability of more than 1.3 times that of Formulation C (31721 ng hr/mL) and an oral bioavailability of more than 1.1 times that of Formulation D (40218 ng hr/mL). EXAMPLE 3 This example demonstrates the physical stability of megestrol acetate dispersions at various concentrations and with the addition of sucrose, flavoring, and preservatives. Megestrol acetate was milled under high energy milling conditions using a NanoMill™2 System (Elan Drug Delivery, Inc.) in the presence of a preservative/buffer system consisting of sodium benzoate, citric acid monohydrate, and sodium citrate dihydrate. After milling, the resulting dispersion was diluted with water, sucrose, flavoring, and additional preservative/buffer to prepare dispersions containing 3% (w/w), 5% (w/w), or 9% (w/w) megestrol acetate. The resulting formulations are shown in Table 4. The physical stability of the formulations was then monitored at 25° C., 40° C., and 50° C. TABLE 4 Formulation Summary Concentrated Diluted, Flavored Dispersions Nanoparticle Formulation E Formulation F Formulation G Dispersion 3% Dispersion 5% Dispersion 9% Dispersion API and Excipients g/kg g/kg g/kg g/kg Megestrol Acetate, USP 325.000 30.000 50.000 90.000 Hydroxypropyl Methylcellulose, USP 65.000 6.000 10.000 18.000 Docusate Sodium, USP 3.250 0.300 0.500 0.900 Sodium Beuzoate, USP 1.214 1.826 1.777 1.681 Sodium Citrate Dihydrate, USP 0.910 0.091 0.089 0.084 Citric Acid Monohydrate, USP 0.061 1.369 1.333 1.260 Sucrose, USP 50.000 50.000 50.000 Natural and Artificial Lemon Flavor 0.400 0.400 0.400 Artificial Lime Flavor 0.400 0.400 0.400 Purified Water, USP 604.600 909.614 885.500 837.280 API = active pharmaceutical ingredient Particle size measurements (Table 5) were used to assess the physical stability. The results show almost no increase in the mean particle size at either 25° C. or 40° C., and only a slight increase in the mean particle size at 50° C. 126 days of stability measurements were obtained for the 5% and 9% dispersions and 33 days of stability were obtained for the 3% dispersion, which was prepared at a later date. TABLE 5 Mean particle size (nm) 3% Dispersion 5% Dispersion 9% Dispersion 25° C. 40° C. 50° C. 25° C. 40° C. 50° C. 25° C. 40° C. 50° C. 0 days 148 148 148 169 169 169 169 169 169 30 days 172 171 187 172 170 179 33 days 141 144 173 126 days 171 174 188 168 175 182 EXAMPLE 4 The purpose of this Example was to demonstrate the improved viscosity characteristics of the dispersions of this invention. The viscosities of three formulations of this invention (E, F, and G as described in Example 3) and two conventional commercial formulations (Formulations C and D as described in Example 2) were determined using a rheometer (model CVO-50, Bohlin Instruments). The measurements were performed at a temperature of 20° C. using a double gap (40/50) geometry. The viscosities of the Formulations of this invention were found to be nearly Newtonian (i.e., the viscosity being independent of shear rate), and were 1.5, 2.0, and 3.5 mPa s for the 30, 50, and 90 mg/mL concentrations, respectively. The viscosity dependence on concentration is illustrated in FIG. 1. The commercial formulations C and D were shear thinning in nature. Such samples cannot be characterized by a single viscosity but rather a series of viscosities measured at different shear rates. This is most conveniently illustrated as viscosity—shear rate curves as shown in FIG. 2. The commercial samples and the three formulations of this invention are compared in Table 6 below. Viscosities are in units of mPa s. TABLE 6 Shear Rates of Commercial Megestrol Formulations (D and C) and the Nanoparticulate Megestrol Formulations of the Invention (E, F, & G) Commercial Samples Formulations E, F, & G Shear Rate Formulation D Formulation C (E) 30 mg/mL (F) 50 mg/mL (G) 90 mg/mL s−1 (mPa s) (mPa s) (mPa s) (mPa s) (mPa s) 0.1 4010 2860 1.5 2.0 3.5 1 929 723 ″ ″ ″ 10 215 183 ″ ″ ″ 100 49.9 46.3 ″ ″ ″ * These samples were not measured at the 0.1 and 1 s−1 shear rates (the shear range was ca 2 to 100 s−1) but the assessment that these exhibit Newtonian flow properties justifies the entries. EXAMPLE 5 The purpose of this Example was to visually demonstrate the difference between the viscosity characteristics of liquid megestrol formulations of the invention as compared to conventional liquid megestrol formulations. A sample of a 50 mg/mL nanoparticulate dispersion of megestrol acetate and two conventional commercial formulations at 40 mg/mL (Formulations C and D as described in Example 2) were each placed in a vial, which was then shaken. Attached as FIG. 3 is a photograph of the thee vials, which from left to right are the nanoparticulate megestrol acetate dispersion, Formulation C, and Formulation D. The vial with the nanoparticulate dispersion shows a thin, silky, almost shear film coating the vial. In contrast, the vials containing the two commercial formulations show a gritty residue coating. Such a gritty residue is the same residue which coats a patient's mouth and throat upon administration. Such a coating is highly unpleasant, particularly for patients suffering from wasting (i.e., unable to eat). Thus, FIG. 3 visually demonstrates the appeal of a liquid oral nanoparticulate megestrol formulation of the invention as compared to conventional commercial liquid oral megestrol formulations. EXAMPLE 6 The purpose of this example was to prepare nanoparticulate compositions of megestrol acetate using various surface stabilizers. 5% megestrol acetate (Par Pharmaceuticals, Inc.) was combined with 1.25% of various surface stabilizers: tyloxapol (Sterling Organics), Tween 80 (Spectrum Quality Products), Pluronic F-108 (BASF), Plasdone S-630 (ISP), hydroxypropylmethylcellulose (HPMC) (Shin Etsu), hydroxypropylcellulose (HPC-SL) (Nippon Soda Co., Ltd.), Kollidon K29/32 (polyvinylpyrrolidone) (ISP), or lysozyme (Fordras). For each combination of megestrol acetate and surface stabilizer, the surface stabilizer was first dissolved in 7.875 g water for injection (WFI) (Abbott Laboratories, Inc.), followed by the addition of the milling media, PolyMill™-500 (Dow Chemical, Co.), and 0.42 g megestrol. The slurries were charged into each of eight 18 cc NanoMill® (Elan Drug Delivery) chambers and milled for 30 min. Upon completion of milling the dispersions were harvested with a 26 gauge needle yielding the following particle sizes shown in Table 7. All particle size distribution analyses were conducted on a Horiba LA-9 10 Laser Light Scattering Particle Size Distribution Analyzer (Horiba Instruments, Irvine, Calif.). RO-water was utilized as the liquid dispersing medium and a flow-through sample cell was used for all measurements. All samples were assayed in 150 cc liquid medium. TABLE 7 Megestrol Conc. Surface Stabilizer/Conc. Mean Particle Size 5% tyloxapol; 1.25% 214 nm 5% Tween 80; 1.25% 210 nm 5% Pluronic F-108; 1.25% 459 nm 5% Plasdone S-630; 1.25% 292 nm 5% HPMC; 1.25% 314 nm 5% HPC-SL; 1.25% 623 nm 5% PVP K29/32; 1.25% 24816 nm 5% lysozyme; 1.25% 179 nm The results show that tyloxapol, Tween 80, and lysozyme produced small particles without substantial aggregation. Pluronic F-108, Plasdone S-630, HPMC, HPC-SL, and K29/32 had larger particle sizes, indicating that aggregation was occurring. Thus, at the particular concentration of drug and surface stabilizer, using the described milling method, Pluronic F-108, Plasdone S-630, HPMC, HPC-SL, and K29/32 were not preferable surface stabilizers. These surface stabilizers may be useful in nanoparticulate compositions of megestrol at different drug or surface stabilizer concentrations, or when used in conjunction with another surface stabilizer. EXAMPLE 7 The purpose of this example was to prepare nanoparticulate compositions of megestrol acetate using various surface stabilizers. Megestrol acetate (Par Pharmaceuticals, Inc.) and various surface stabilizers, as shown in Table 8, were combined and milled, followed by determination of the particle size and stability of the resulting composition. Materials were obtained as in Example 6. All of the samples were milled using a Dyno®-Mill (Model KDL-Series, Willy Bachofen AG, Basel, Switzerland) equipped with a 150 cc stainless steel batch chamber. Cooling water (approximate temperature 5° C.) was circulated through the mill and chamber during operation. All particle size distribution analyses were conducted on a Horiba LA-910 Laser Light Scattering Particle Size Distribution Analyzer (Horiba Instruments, Irvine, Calif.), as described above in Example 6. Qualitative microscopic assessments of the formulations were performed using a Leica light microscope (Type 301-371.010). Sample preparation involved diluting the product dispersions in RO-water and dispensing about 10 μL onto a glass slide. Oil immersion was utilized in conjunction with 1000× magnification. The physical stability was assessed by storing the dispersion is 20 ml glass scintillation vials in a temperature/humidity controlled chamber at either 5° C., (25° C./60% RH), (40° C./75% RH), (50° C./75% RH), or 55° C. Samples were taken at varying time intervals and the particle size was analyzed. For all formulations, the surface stabilizer(s) was first dissolved in WFI (Abbott Laboratories, Inc.) (75.0 g for Exp. Nos. 1, 2, 3, 7, and 8; 75.2 g for Exp. Nos. 4 and 9; 74.9 g for Exp. Nos. 5 and 6; 70.3 g for Exp. Nos. 10 and 11), followed by combining the surface stabilizer solution megestrol acetate and PolyMill™500 polymeric grinding media. This mixture was then added to the appropriate milling chamber, milled for the time period shown in Table 8, followed by harvesting and vacuum filtering of the megestrol acetate dispersion. TABLE 8 Surface Mean Exp. Megestrol Stabilizer(s) and Particle No. Conc. Conc. Milling Time Size Stability 1 5% 1.25% lysozyme 20 min. 209 nm The sample showed substantial aggregation after incubation in normal saline for 30 minutes as determined by optical microscopy. 2 5% 1.25% Tween 80 75 min. 157 nm Upon storage at 5° C. for 15 days the sample grew to a mean diameter of 577 nm. 3 5% 1.25% tyloxapol 2 hrs. 208 nm Optical microscopoy revealed the presence of elongated “needle-like” crystals. 4 5% 1% Pluronic F127 2 hrs. 228 nm Upon storage at 25° C. for 5 days the sample grew to a mean diameter of 308 nm. 5 5% 1.25% HPMC 75 min. 161 nm Upon storage at 40° C. for 19 days, the sample grew to a mean diameter of 0.0625% SLS1 171 nm. Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in particle sizes of 164 nm and 209 nm, respectively. 6 5% 1.25% HPC-SL, 60 min. 167 nm Upon storage at 40° C. for 15 days, the sample grew to a mean diameter of 0.05% SLS 194 nm. Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in particle sizes of 183 nm and 179 nm, respectively. 7 5% 1.25% HPMC 45 min. 185 nm Upon storage at 40° C. for 6 days, the sample grew to a mean diameter of 313 nm. Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in particle sizes of 2041 nm and 1826 nm, respectively. Optical microscopy revealed aggregation in both the saline and HCl samples. 8 5% 1.25% HPC-SL 45 min. 176 nm Upon storage at 40° C. for 6 days, the sample grew to a mean diameter of 244 nm. Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in particle sizes of 873 nm and 524 nm, respectively. Optical microscopy revealed aggregation in both the saline and HCl samples. 9 5% 1% HPMC 70 min. 152 nm Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in 0.05% SLS particle sizes of 155 nm and 539 nm, respectively. Optical microscopy confirmed that aggregation was present in the sample incubated in saline. 10 10% 2% HPMC 70 min. 150 nm Following harvesting the sample was diluted to 4% API by adding WFI. 0.1% DOSS2 Upon storage at 40° C. for 40 days, the sample had a mean diameter of 146 nm. Optical microscopy revealed small, well dispersed particles. 11 10% 2% HPMC 70 min. 146 nm Upon storage at 40° C. for 19 days, the sample had a mean diameter of 149 nm. 0.1% SLS Optical microscopy revealed small, well dispersed particles. 12 10% 4% lysozyme 60 min. 108 nm Upon storage at 40° C. for 9 days the sample had a mean diameter of 124 nm. Optical microscopy revealed small, well dispersed particles. 1Sodium lauryl sulfate (Spectrum Quality Products) 2Dioctyl Sodium Sulfosuccinate (Cytec) The results shown in Table 8 indicate that the use of lysozyme (Exp. No. 1) as a surface stabilizer resulted in small well dispersed particles with a mean particle size of 209 nm, but the formulation showed aggregation when diluted into a normal saline solution. A megestrol acetate/tyloxapol sample was also stable at higher drug and stabilizer concentrations (Exp. No. 12). Tween 80, tyloxapol, and Pluronic F127 (Exp. Nos. 2, 3, and 4) were effective primary surface stabilizers and produced well-dispersed particles without significant aggregation. Stability measurements, however, revealed rapid crystal growth for all three stabilizers. 5% megestrol acetate/1.25% Tween 80 grew from 157 nm to 577 nm after 15 days at 5° C. 5% megestrol acetate/1.25% tyloxapol showed needle-like crystals when observed under optical microscopy. 5% megestrol acetate/1.25% Pluronic F127 grew from 228 nm to 308 nm after 5 days at 25° C. Because of the rapid crystal growth observed, Tween 80, tyloxapol, and Pluronic F127 were deemed not suitable surface stabilizers at the described drug/surface stabilizer concentrations prepared under the conditions described above. The HPC-SL formulation (Exp. No. 8) showed substantial aggregation indicating that a secondary charged stabilizer would be needed. SLS was added (Exp. No. 6) and the new formulation grew from 167 to 194 nm after storage at 40° C. for 15 days and did not show any substantial aggregation upon incubation in either 0.01N HCl or normal saline. The SLS appeared effective at preventing the aggregation but the sample showed some particle size growth. The HPMC formulation (Exp. No. 7) showed substantial aggregation indicating that a secondary charged stabilizer would be needed. SLS was added (Exp. Nos. 5 and 11), and the new formulations showed only minimal growth from 161 nm to 171 nm (Exp. No. 5), and from 146 to 149 nm (Exp. No. 11), after storage at 40° C. for 19 days. In addition, the composition of Exp. No. 5 did not show any substantial aggregation upon incubation in either 0.01N HCl or normal saline. The SLS was effective at preventing the aggregation without causing significant crystal growth. An attempt was made to reduce the concentration of the primary and secondary stabilizers (Exp. No. 9) and resulted in a post-milling mean diameter of 152 nm. Incubation for 30 minutes at 40° C. in normal saline resulted in particle sizes of 539 nm. Optical microscopy confirmed that aggregation was present in the sample incubated in saline. Docusate sodium (DOSS) was tried as a secondary stabilizer (Exp. No. 10) and resulted in well-dispersed particles with a mean diameter of 150 nm. Upon storage at 40° C. for 40 days, the sample had a mean diameter of 146 nm. Optical microscopy revealed small, well-dispersed particles. DOSS seemed to result in even less particle size growth than SLS. EXAMPLE 8 The purpose of this example was to prepare nanoparticulate compositions of megestrol acetate using various surface stabilizers and further including preservatives or excipients. The materials and methods were the same as in Example 7, except that for several of the examples different sources of megestrol acetate were used (See Table 9). In addition, for Exp. Nos. 5, a NanoMill® milling system (Elan Drug Delivery) was used. Several different combinations of megestrol acetate, surface stabilizer(s), and one or more preservatives or excipients were prepared, following by testing the compositions for particle size and stability. The surface stabilizer(s) and one or more preservatives were first dissolved in WFI, followed by combining the solution with megestrol acetate and the grinding media. This mixture was then added to the milling chamber and milled for the time period set forth in Table 9, below. For several of the experiments, following milling the megestrol acetate dispersion was combined with a flavored suspension. The stability of the resultant composition was then evaluated. The formulation details and results are shown in Table 9, below. TABLE 9 Surface Mean Megestrol Stabilizer(s) Milling Particle Exp. Conc. and Conc. Preservatives/Excipients Time Size Stability 1 10% 2% HPMC Sodium Benzoate (0.4 g), 75 min 146 nm After milling a flavored suspension was prepared 0.1% DOSS Sodium Citrate Dihydrate (20 mg) by adding sucrose (2.5 g), xanthan gum Citric Acid Monohydrate (0.3 g) (0.113 g), glycerol (13.75 g), lemon flavor (0.1 g), WFI (18.6 g), and 20.0 g of the milled dispersion. Upon storage at 40° C. for 24 days, the sample showed aggregation with a mean diameter of 837 nm. Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in particle sizes of 206 nm and 3425 nm, respectively. Optical microscopy confirmed that the sample incubated in saline had aggregated. 2 25% 5% HPMC Sodium Benzoate (0.11 g) 95 min. See right 16 g of the milled drug dispersion was combined 0.05% DOSS Citric Acid Monohydrate (0.08 g) column. with sucrose (5 g), lime flavor (80 mg), and WFI (78.9 g). The diluted drug dispersion had a mean diameter of 192. After 6 days at 55° C. the particles had a mean diameter of 10 microns, indicating substantial aggregation 3 25% 5% HPMC, Sodium Benzoate (0.11 g) 95 min. See right 16 g of the milled drug dispersion was combined 0.15% DOSS Citric Acid Monohydrate (0.08 g) column. with sucrose (5 g), lime flavor (80 mg), and WFI (78.9 g). The diluted drug dispersion had a mean diameter of 173 nm. After 12 days at 55° C. the particles had a mean diameter of 295 nm. 4 32.5%1 6.5% HPMC Sodium Benzoate (13.07 g) 15.5 hrs 160 nm Upon storage at 50° C. for 44 days, the 0.33% DOSS Sodium Citrate Dihydrate (0.65 g) mean diameter was 190 nm. Citric Acid Monohydrate (9.8 g) 5 32.5% 6.5% HPMC Sodium Benzoate (9.71 g) 12 hrs 147 nm Upon storage at 50° C. for 44 days the 0.33% DOSS Sodium Citrate Dihydrate (0.49 g) mean diameter was 178 nm. Citric Acid Monohydrate (7.28 g) 1Pharmacia 2Pharmabios In Exp. No. 1 of Table 9, a sweetened, flavored dispersion was prepared by mimicking the current commercial formulation of megestrol acetate that contains sucrose, xanthan gum, glycerol, lemon and lime flavors, and is preserved and buffered with sodium benzoate and citric acid. Upon storage at 40° C. for 24 days the sample showed aggregation with a mean diameter of 837 nm. Incubation for 30 minutes at 40° C. in 0.01N HCl or normal saline resulted in particle sizes of 206 nm and 3425 nm, respectively. Optical microscopy confirmed that the sample incubated in saline had aggregated. The aggregation upon storage indicated that this particular combination of drug and surface stabilizer, at the concentrations used and methodology employed to make the compositions, would not be an effective formulation. For Exp. Nos. 4 and 5, the formulation was scaled-up in a NanoMill™-2 system to determine if the scale-up would effect the physical stability. Two different sources of megestrol acetate were tested: Pharmacia and Pharmabios. The product of Exp. No. 4 had a mean diameter of 160 nm without ultrasound. Upon storage at 50° C. for 44 days the mean diameter was 190 nm. The composition of Exp. No. 5 had a post-milling mean diameter of 147 nm without ultrasound. Upon storage at 50° C. for 44 days the mean diameter was 178 nm. Both sources of active agent milled effectively and showed little particle size growth even at 50° C. The results of Examples 6 and 7 showed that high energy milling with polymeric attrition media could be used to produce stable nanoparticulate colloidal dispersions of megestrol acetate suitable for oral administration to animals or humans. The primary stabilizer HPMC required the presence of DOSS or SLS to prevent aggregation at the concentrations of drug and stabilizer tested (other combinations of drug and HPMC concentrations may result in a stable composition without the addition of a second surface stabilizer). In general, average particle sizes of less than about 160 nm could be obtained. Tests conducted with two sources of megestrol acetate revealed that both sources milled effectively and exhibited excellent physical stability. Based on mean particle size, physical stability, and the pre-clinical dog study, the best nanoparticulate megestrol acetate formulation for commercial development, based on the results of the data given in the examples, consisted of 32.5% megestrol acetate, 6.5% HPMC, and 0.325% DOSS (i.e., a drug:HPMC ratio of 1:5 and a drug:DOSS ratio of 1:100. The formulation milled effectively in the presence of preserved water (0.2% sodium benzoate, 0.01% sodium citrate dihydrate, and 0.15% citric acid monohydrate). Upon dilution with preserved water, flavors, and sucrose none of the dispersions showed severe aggregation, except for the dispersions containing xanthan gum (data not shown) or low levels of DOSS. The alcohol-based flavors did not effect the physical stability nor did several freeze-thaw cycles (data not shown). EXAMPLE 9 This example compares the pharmacokinetic parameters of nanoparticulate megestrol acetate formulations of the invention with a conventional microparticulate formulation of megestrol acetate. Results were obtained from a fasted study group consisting of 36 male subjects, 18 years of age or older. For a fed study group, results from 32 subjects were analyzed. Subjects in the fasted study group and the fed study group were administered study drugs in four successive periods. Treatment A (1×150 mg drug as 5 ml of a 3% megestrol acetate nanoparticulate formulation) was administered in the first period. Reference Treatment B (1×800 mg drug as 20 ml of a 4% megestrol acetate Megace® Oral Suspension) was administered in the second period. Treatment C (1×250 mg drug as 5 ml of a 5% megestrol acetate nanoparticulate formulation) was administered in the third period. Treatment D (1×450 mg drug as 5 ml of a 9% megestrol acetate nanoparticulate formulation) was administered in the fourth period. The formulations of Treatments A, C, and D are listed in Table 10 below, with particle size information (microns) provided in Table 11. In each period, subjects were confined from at least 10 hours prior to drug administration to after the last sample collection. In the fasted study group, no food was consumed from at least 10 hours before dosing to at least 4 hours after dosing. In the fed study group, a high-calorie breakfast (containing about 800 to 1000 calories, approximately 50% of which were from fat) was served within 30 minutes prior to dosing; dosing occurred within 5 minutes after the breakfast was completed. A controlled meal was served to both groups after 4 hours after dosing, and standard meals were served at appropriate times thereafter. The meals in all four periods were identical. Subjects in the fasted study group were not allowed fluid intake from 1 hour before dosing to 1 hour after. Subjects in the fed study group were also not allowed fluid intake during this period except for fluids provided with the high-calorie breakfast. Water was provided ad libitum to both study groups at all other times. Blood samples were obtained before dosing, at half-hourly intervals in the 6 hours following dosing, and at 7, 8, 12, 16, 20, 24, 36, 48, 72, and 96 hours after dosing. Megestrol acetate in plasma samples was then determined. Table 12 below summarizes pharmacokinetic data for the fasted study group, and Table 13 below summarizes pharmacokinetic data for the fed study group. Treatments A, C, and D in fasting subjects produced dose-normalized values for AUC0-T and AUC0-inf that were approximately twice those of Reference Treatment B. Maximum dose-normalized megestrol acetate concentrations in Treatments A, C, and D were approximately 9 to 12 times that of Reference Treatment B. The maximum megestrol acetate concentration for the 150 mg-dose of Treatment A was approximately twice that of the 800 mg-dose of reference Treatment B. Moreover, comparable values of AUC0-t and AUC0-inf were observed for the 450 mg-dose of Treatment D and the 800 mg-dose of Reference Treatment B. Treatments A, C, and D in fed subjects produced dose-normalized values for AUC0-t and AUC0-inf that were approximately 8 to 10% greater than those of Reference Treatment B. Maximum dose-normalized megestrol acetate concentrations in Treatments A, C, and D were approximately 38 to 46% greater than that of Reference Treatment B. Megestrol acetate onset for Treatments A, C, and D was comparable to Reference Treatment B. Nanoparticulate megestrol acetate formulations, therefore, exhibited superior oral bioavailability, relative to the Megace® Oral Suspension, in fasting and fed human subjects. TABLE 10 Formulations for Megestrol Acetate Oral Suspension 3, 5% and 9% Strengths 3% w/w 5% w/w 9% w/w Ingredients (30 mg/mL) (50 mg/mL) (90 mg/mL) Megestrol Acetate 3.000 5.000 9.000 Hydroxypropyl 0.600 1.000 1.800 Methylcellulose Docusate Sodium 0.030 0.050 0.090 Sodium Benzoate 0.183 0.178 0.168 Sodium Citrate Dihydrate 0.009 0.009 0.008 Citric Acid Monohydrate 0.137 0.133 0.126 Sucrose 5.000 5.000 5.000 Natural and Artificial Lemon 0.040 0.040 0.040 Flavor Artificial Lime Flavor 0.040 0.040 0.040 Purified Water 90.961 88.550 83.727 TOTAL 100.000 100.000 100.000 TABLE 11 Particle Size Data for the Megestrol Acetate Oral Suspensions* Strength 30 mg/g Strength 50 mg/g Strength 90 mg/g d(0.1) d(0.5) d(0.9) d(0.1) d(0.5) d(0.9) d(0.1) d(0.5) d(0.9) Initial 0.068 0.123 0.223 0.069 0.125 0.229 0.068 0.124 0.227 ACC/1 0.070 0.129 0.237 0.070 0.127 0.231 0.070 0.127 0.230 month ACC/2 0.070 0.127 0.231 0.070 0.127 0.233 0.073 0.126 0.221 months ACC/3 0.070 0.129 0.237 0.070 0.128 0.235 0.070 0.128 0.234 months RT 3 0.070 0.128 0.237 0.073 0.128 0.224 0.067 0.121 0.223 months *All particle sizes are given in microns. “d(0.1)” means distribution of smallest 10% of the particles, i.e., d(0.1) 10 μm means 10% of the particles are less than 10%. Similarly, “d(0.5)” means distribution of the smallest 50% of the particles, and “d(0.9)” means distribution of the smallest 90% of the particles. Thus, d(0.9) means that 90% of the particles are less than XX μm. TABLE 12 Summary of Pharmacokinetic Data in Fasted Human Subjects* Treatment A Ref. Treatment B Treatment C Treatment D Parameters (Mean ± SD) (Mean ± SD) (Mean ± SD) (Mean ± SD) AUC0-t 2800 ± 900 7000 ± 5000 4700 ± 1800 8500 ± 3200 AUC0-inf 3100 ± 1000 9000 ± 9000 5200 ± 2100 9000 ± 4000 Cmax 410 ± 120 190 ± 110 650 ± 200 950 ± 270 Tmax 1.7 ± 0.9 6 ± 6 1.6 ± 1.0 1.7 ± 1.1 t1/2 35 ± 13 31 ± 19 34 ± 10 34 ± 12 Kel 0.023 ± 0.011 0.026 ± 0.009 0.022 ± 0.008 0.023 ± 0.008 AUC0-t (ng · hr/ml) = Area under the curve from time zero to the last measurable concentration; AUC0-inf (ng · hr/ml) = Area under the curve from time zero to infinity; Cmax (ng/ml) = Maximum plasma concentration; Tmax (hr) = Time to occurrence of Cmax; t1/2 (hr) = Apparent elimination half-life; Kel (1/hr) = Elimination rate constant; *n = 36. TABLE 13 Summary of Pharmacokinetic Data in Fed Human Subjects* Treatment A Ref. Treatment B Treatment C Treatment D Parameters (Mean ± SD) (Mean ± SD) (Mean ± SD) (Mean ± SD) AUC0-t 3500 ± 1100 17000 ± 5000 5700 ± 1600 10500 ± 3000 AUC0-inf 3900 ± 1300 19000 ± 6000 6300 ± 2000 12000 ± 4000 Cmax 380 ± 140 1400 ± 400 590 ± 170 1080 ± 290 Tmax 3.8 ± 3.5 3.9 ± 0.9 3.4 ± 1.7 3.2 ± 1.7 t1/2 35 ± 12 33 ± 9 35 ± 10 38 ± 12 Kel 0.023 ± 0.013 0.023 ± 0.007 0.023 ± 0.009 0.021 ± 0.008 AUC0-t (ng · hr/ml) = Area under the curve from time zero to the last measurable concentration; AUC0-inf (ng · hr/ml) = Area under the curve from time zero to infinity; Cmax (ng/ml) = Maximum plasma concentration; Tmax (hr) = Time to occurrence of Cmax; t1/2 (hr) = Apparent elimination half-life; Kel (1/hr) = Elimination rate constant; *n = 32. EXAMPLE 10 This example compares the pharmacokinetic parameters of a nanoparticulate megestrol acetate formulations to a conventional microparticulate formulation of megestrol acetate (Megace® by Bristol Myers Squibb Co.). Results were obtained from a fasted study group consisting of 33 male subjects, 18 years of age or older. The nanoparticulate megestrol acetate compositions were prepared as described in Example 10. Subjects were administered study drugs in four successive periods. Treatment A (575 mg of nanoparticulate megestrol acetate formulation in 5 ml oral suspension) was administered in the first period. Reference Treatment B (800 mg of megestrol acetate (Megace® by Bristol Myers Squibb Co.) in 20 ml oral suspension) was administered in the second period. Treatment C (625 mg of nanoparticulate megestrol acetate formulation in 5 ml oral suspension) was administered in the third period. Treatment D (675 mg of nanoparticulate megestrol acetate formulation in 5 ml oral suspension) was administered in the fourth period. Table 14 provides the formulations of Treatments A, C and D. TABLE 14 Formulations of Nanoparticulate Megestrol Acetate Oral Suspensions 115 mg/mL 125 mg/mL 135 mg/mL Dosage Conc. Conc. Conc. FINAL AMOUNTS Weight (g) (mg/mL) Weight (g) (mg/mL) Weight (g) (mg/mL) Megestrol Acetate 37,500.0 115.00 37,500.0 125.00 37,500.0 135.00 HPMC 7,500.0 23.00 7,500.0 25.00 7,500.0 27.00 Docusate Sodium 375.0 1.15 375.0 1.25 375.0 1.35 Sodium Benzoate 530.4 1.63 481.4 1.60 439.7 1.58 Sodium Citrate Dihydrate 26.5 0.08 24.0 0.08 22.0 0.08 Citric Acid Monohydrate 397.8 1.22 361.1 1.20 329.8 1.19 Sucrose 15,473.0 47.45 14,044.0 46.81 12,826.7 46.18 Lemon Flavor 123.8 0.38 112.4 0.37 102.6 0.37 Lime Flavor 123.8 0.38 112.4 0.37 102.6 0.37 Water 277,080.1 — 251,489.7 — 229,690.5 — TOTAL (Weight, g) 339,130.4 312,000.0 — 288,888.9 — TOTAL (volume, L) 326.1 300.0 — 277.8 — The nanoparticulate megestrol acetate formulations were prepared by milling a concentrated dispersion of the drug substance followed by dilution to yield the final products. Hydroxypropyl methylcellulose and docusate sodium were used as stabilizing agents. The formulations were processed in a NanoMill-10 horizontal media mill (Netzsch USA) for 20 hours. The attrition media used was 500 μm crosslinked polystyrene (PolyMill™-500). The dispersion further comprised 0.13% sodium benzoate, 0.01% sodium citrate dihydrate, and 0.1% citric acid monohydrate. Milled dispersion was diluted to final megestrol acetate concentrations of 115 mg/mL (575 mg/5 mL), 125 mg/mL (625 mg/5 mL) and 135 mg/mL (675 mg/5 mL). The final compositions additionally contained sweetening and flavoring agents. Particle size determinations were performed on a Malvern Mastersizer 2000 instrument. The particle size distributions of the nanoparticulate megestrol acetate compositions are provided in Table 15. TABLE 15 Concentration Mean particle (mg/mL) size (nm) 50% < (nm) 90% < (nm) 115 144 130 234 125 144 127 237 135 145 131 236 In each period, subjects were confined from at least 11 hours prior to drug administration until after the 24.0 hour post-dose sample collection. After a supervised fast of at least 10 hours, subjects were fed a high-calorie meal containing about 800 to 1000 calories (approximately 150 calories from carbohydrates and 500-600 calories from fat). The meal consisted of two eggs fried in butter, two slices of toast with butter, two strips of bacon, approximately 128 g of hash brown potatoes and 200 ml of whole milk. The meals in all four periods were identical. The meal was completed within 30 minutes, and subjects were dosed 30 minutes after starting the meal. The suspensions of Treatments A, B, C and D were administered via Slip Tip syringe directly into the mouth and swallowed. The syringe was rinsed three (3) times with approximately 5 ml (Treatments A, C and D) or 20 ml (Treatment B) of water. Following drug administration, approximately 225 ml (Treatments A, C and D) or 180 ml (Treatment B) of water was ingested. For each period, a total of 24 blood samples were drawn from each subject. Blood samples were collected in EDTA blood tubes prior to drug administration and 0.250, 0.500, 0.750, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 8.00, 12.0, 16.0, 20.0, 24.0, 36.0, 48.0, 72.0 and 96.0 hours post-dose (1×7 mL for each sampling time). Table 16 below summarizes the pharmacokinetic data, while Table 17 provides the statistical comparisons of the treatments. TABLE 16 Pharmacokinetic Parameters Test-1 (Megtestrol Acetate Reference: 575 mg/5 mL (A)) (Megace 40 mg/mL (B)) Parameters Mean ± SD CV (%) Mean ± SD Cv (%) AUC0-t (ng-h/mL) 13657.52 ± 3900.50 28.56 16896.21 ± 4942.51 29.25 AUC0-inf (ng-h/mL) 14743.33 ± 4451.31 30.19 18274.06 ± 5623.07 30.77 Cmax (ng/mL) 1420.73 ± 420.79 2962 1400.66 ± 350.57 25.03 Tmax (h) 3.75 ± 1.57 41.85 3.88 ± 1.02 26.38 Tmax* (h) 4.50 ± 1.00 — 4.50 ± 1.00 — Kel (h−1) 0.0224 ± 0.0062 27.44 0.0238 ± 0.0054 22.84 T1/2 el (h) 32.78 ± 7.47 22.80 30.53 ± 6.66 21.80 Test-2 (Megtestrol Acetate Test-3 (Megestrol 625 mg/5 mL (C)) Acetate 675 mg/5 mL (D)) Parameters Mean ± SD CV (%) ± ± SD Cv (%) AUC0-t (ng-h/mL) 14682.37 ± 4844.60 33.00 15323.29 ± 4525.94 29.54 AUC0-inf (ng-h/mL) 16081.76 ± 5563.09 34.59 16738.88 ± 5432.52 32.45 Cmax (ng/mL) 1516.79 ± 389.01 25.65 1645.74 ± 455.71 27.69 Tmax (h) 2.52 ± 1.60 63.52 3.13 ± 1.64 52.55 Tmax* (h) 2.50 ± 3.50 — 3.50 ± 3.00 — Kel (h−1) 0.0211 ± 0.0055 26.21 0.0211 ± 0.0054 25.64 T1/2 el (h) 34.75 ± 7.81 22.48 34.83 ± 8.12 23.30 *Median and interquartile ranges are presented. AUC0-t (ng · h/ml) = Area under the curve from time zero to the last measurable concentration AUC0-inf (ng · h/ml) = Area under the curve from time zero to infinity Cmax (ng/ml) = Maximum plasma concentration Tmax (h) = Time to occurrence of Cmax t1/2 el (h) = elimination half-life Kel (l/h) = elimination rate constant TABLE 17 Treatment Comparisons Statistical Intra- Analysis Treatment 90% Geometric CL2 Subject (ANOVA) Comparisons Ratio1 Lower Upper CV AUC0-t Megestrol Actate 575 mg/5 mL (A) vs 81.06% 78.20% 84.03% 8.82% Megace 40 mg/mL (B) Megestrol Actate 625 mg/5 mL (C) vs 86.29% 83.24% 89.45% Megace 40 mg/mL (B) Megestrol Actate 675 mg/5 mL (D) vs 90.63% 87.43% 93.95% Megace 40 mg/mL (B) AUC0-inf Megestrol Actate 575 mg/5 mL (A) vs 80.92% 77.95% 84.00% 9.16% Megace 40 mg/mL (B) Megestrol Actate 625 mg/5 mL (C) vs 87.33% 84.12% 90.65% Megace 40 mg/mL (B) Megestrol Actate 675 mg/5 mL (D) vs 91.31% 87.96% 94.79% Megace 40 mg/mL (B) Cmax Megestrol Actate 575 mg/5 mL (A) vs 100.62% 94.10% 107.69% 16.51% Megace 40 mg/mL (B) Megestrol Actate 625 mg/5 mL (C) vs 108.18% 101.17% 115.69% Megace 40 mg/mL (B) Megestrol Actate 675 mg/5 mL (D) vs 116.72% 109.15% 124.82% Megace 40 mg/mL (B) 1Calculated using least-squares means 290% Geometric Confidence Interval using In-transformed data Tables 16 and 17 demonstrate that Treatments A, C, and D produced similar pharmakinetics as Treatment B. FIGS. 4 and 5 show that Treatments A, C and D produce similar concentration-time curves as Treatment B. It will be apparent to those skilled in the art that various modifications and variations can be made in the methods and compositions of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>A. Background Regarding Nanoparticulate Compositions Nanoparticulate compositions, first described in U.S. Pat. No. 5,145,684 (“the '684 patent”), are particles consisting of a poorly soluble therapeutic or diagnostic agent having adsorbed onto the surface thereof a non-crosslinked surface stabilizer. The '684 patent does not describe nanoparticulate compositions of megestrol. Methods of making nanoparticulate compositions are described, for example, in U.S. Pat. Nos. 5,518,187 and 5,862,999, both for “Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,718,388, for “Continuous Method of Grinding Pharmaceutical Substances;” and U.S. Pat. No. 5,510,118 for “Process of Preparing Therapeutic Compositions Containing Nanoparticles.” Nanoparticulate compositions are also described, for example, in U.S. Pat. No. 5,298,262 for “Use of Ionic Cloud Point Modifiers to Prevent Particle Aggregation During Sterilization;” U.S. Pat. No. 5,302,401 for “Method to Reduce Particle Size Growth During Lyophilization;” U.S. Pat. No. 5,318,767 for “X-Ray Contrast Compositions Useful in Medical Imaging;” U.S. Pat. No. 5,326,552 for “Novel Formulation For Nanoparticulate X-Ray Blood Pool Contrast Agents Using High Molecular Weight Non-ionic Surfactants;” U.S. Pat. No. 5,328,404 for “Method of X-Ray Imaging Using Iodinated Aromatic Propanedioates;” U.S. Pat. No. 5,336,507 for “Use of Charged Phospholipids to Reduce Nanoparticle Aggregation;” U.S. Pat. No. 5,340,564 for “Formulations Comprising Olin 10-G to Prevent Particle Aggregation and Increase Stability;” U.S. Pat. No. 5,346,702 for “Use of Non-Ionic Cloud Point Modifiers to Minimize Nanoparticulate Aggregation During Sterilization;” U.S. Pat. No. 5,349,957 for “Preparation and Magnetic Properties of Very Small Magnetic-Dextran Particles;” U.S. Pat. No. 5,352,459 for “Use of Purified Surface Modifiers to Prevent Particle Aggregation During Sterilization;” U.S. Pat. No. 5,399,363 and U.S. Pat. No. 5,494,683, both for “Surface Modified Anticancer Nanoparticles;” U.S. Pat. No. 5,401,492 for “Water Insoluble Non-Magnetic Manganese Particles as Magnetic Resonance Enhancement Agents;” U.S. Pat. No. 5,429,824 for “Use of Tyloxapol as a Nanoparticulate Stabilizer;” U.S. Pat. No. 5,447,710 for “Method for Making Nanoparticulate X-Ray Blood Pool Contrast Agents Using High Molecular Weight Non-ionic Surfactants;” U.S. Pat. No. 5,451,393 for “X-Ray Contrast Compositions Useful in Medical Imaging;” U.S. Pat. No. 5,466,440 for “Formulations of Oral Gastrointestinal Diagnostic X-Ray Contrast Agents in Combination with Pharmaceutically Acceptable Clays;” U.S. Pat. No. 5,470,583 for “Method of Preparing Nanoparticle Compositions Containing Charged Phospholipids to Reduce Aggregation;” U.S. Pat. No. 5,472,683 for “Nanoparticulate Diagnostic Mixed Carbamic Anhydrides as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,500,204 for “Nanoparticulate Diagnostic Dimers as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,518,738 for “Nanoparticulate NSAID Formulations;” U.S. Pat. No. 5,521,218 for “Nanoparticulate Iododipamide Derivatives for Use as X-Ray Contrast Agents;” U.S. Pat. No. 5,525,328 for “Nanoparticulate Diagnostic Diatrizoxy Ester X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,543,133 for “Process of Preparing X-Ray Contrast Compositions Containing Nanoparticles;” U.S. Pat. No. 5,552,160 for “Surface Modified NSAID Nanoparticles;” U.S. Pat. No. 5,560,931 for “Formulations of Compounds as Nanoparticulate Dispersions in Digestible Oils or Fatty Acids;” U.S. Pat. No. 5,565,188 for “Polyalkylene Block Copolymers as Surface Modifiers for Nanoparticles;” U.S. Pat. No. 5,569,448 for “Sulfated Non-ionic Block Copolymer Surfactant as Stabilizer Coatings for Nanoparticle Compositions;” U.S. Pat. No. 5,571,536 for “Formulations of Compounds as Nanoparticulate Dispersions in Digestible Oils or Fatty Acids;” U.S. Pat. No. 5,573,749 for “Nanoparticulate Diagnostic Mixed Carboxylic Anydrides as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,573,750 for “Diagnostic Imaging X-Ray Contrast Agents;” U.S. Pat. No. 5,573,783 for “Redispersible Nanoparticulate Film Matrices With Protective Overcoats;” U.S. Pat. No. 5,580,579 for “Site-specific Adhesion Within the GI Tract Using Nanoparticles Stabilized by High Molecular Weight, Linear Poly(ethylene Oxide) Polymers;” U.S. Pat. No. 5,585,108 for “Formulations of Oral Gastrointestinal Therapeutic Agents in Combination with Pharmaceutically Acceptable Clays;” U.S. Pat. No. 5,587,143 for “Butylene Oxide-Ethylene Oxide Block Copolymers Surfactants as Stabilizer Coatings for Nanoparticulate Compositions;” U.S. Pat. No. 5,591,456 for “Milled Naproxen with Hydroxypropyl Cellulose as Dispersion Stabilizer;” U.S. Pat. No. 5,593,657 for “Novel Barium Salt Formulations Stabilized by Non-ionic and Anionic Stabilizers;” U.S. Pat. No. 5,622,938 for “Sugar Based Surfactant for Nanocrystals;” U.S. Pat. No. 5,628,981 for “Improved Formulations of Oral Gastrointestinal Diagnostic X-Ray Contrast Agents and Oral Gastrointestinal Therapeutic Agents;” U.S. Pat. No. 5,643,552 for “Nanoparticulate Diagnostic Mixed Carbonic Anhydrides as X-Ray Contrast Agents for Blood Pool and Lymphatic System Imaging;” U.S. Pat. No. 5,718,388 for “Continuous Method of Grinding Pharmaceutical Substances;” U.S. Pat. No. 5,718,919 for “Nanoparticles Containing the R(−)Enantiomer of Ibuprofen;” U.S. Pat. No. 5,747,001 for “Aerosols Containing Beclomethasone Nanoparticle Dispersions;” U.S. Pat. No. 5,834,025 for “Reduction of Intravenously Administered Nanoparticulate Formulation Induced Adverse Physiological Reactions;” U.S. Pat. No. 6,045,829 “Nanocrystalline Formulations of Human Immunodeficiency Virus (HIV) Protease Inhibitors Using Cellulosic Surface Stabilizers;” U.S. Pat. No. 6,068,858 for “Methods of Making Nanocrystalline Formulations of Human Immunodeficiency Virus (HIV) Protease Inhibitors Using Cellulosic Surface Stabilizers;” U.S. Pat. No. 6,153,225 for “Injectable Formulations of Nanoparticulate Naproxen;” U.S. Pat. No. 6,165,506 for “New Solid Dose Form of Nanoparticulate Naproxen;” U.S. Pat. No. 6,221,400 for “Methods of Treating Mammals Using Nanocrystalline Formulations of Human Immunodeficiency Virus (HIV) Protease Inhibitors;” U.S. Pat. No. 6,264,922 for “Nebulized Aerosols Containing Nanoparticle Dispersions;” U.S. Pat. No. 6,267,989 for “Methods for Preventing Crystal Growth and Particle Aggregation in Nanoparticle Compositions;” U.S. Pat. No. 6,270,806 for “Use of PEG-Derivatized Lipids as Surface Stabilizers for Nanoparticulate Compositions;” U.S. Pat. No. 6,316,029 for “Rapidly Disintegrating Solid Oral Dosage Form,” U.S. Pat. No. 6,375,986 for “Solid Dose Nanoparticulate Compositions Comprising a Synergistic Combination of a Polymeric Surface Stabilizer and Dioctyl Sodium Sulfosuccinate,” U.S. Pat. No. 6,428,814 for “Bioadhesive Nanoparticulate Compositions Having Cationic Surface Stabilizers;” U.S. Pat. No. 6,431,478 for “Small Scale Mill;” and U.S. Pat. No. 6,432,381 for “Methods for Targeting Drug Delivery to the Upper and/or Lower Gastrointestinal Tract,” all of which are specifically incorporated by reference. In addition, U.S. Patent Application No. 20020012675 A1, published on Jan. 31, 2002, for “Controlled Release Nanoparticulate Compositions,” describes nanoparticulate compositions, and is specifically incorporated by reference. Amorphous small particle compositions are described, for example, in U.S. Pat. No. 4,783,484 for “Particulate Composition and Use Thereof as Antimicrobial Agent;” U.S. Pat. No. 4,826,689 for “Method for Making Uniformly Sized Particles from Water-Insoluble Organic Compounds;” U.S. Pat. No. 4,997,454 for “Method for Making Uniformly-Sized Particles From Insoluble Compounds;” U.S. Pat. No. 5,741,522 for “Ultrasmall, Non-aggregated Porous Particles of Uniform Size for Entrapping Gas Bubbles Within and Methods;” and U.S. Pat. No. 5,776,496, for “Ultrasmall Porous Particles for Enhancing Ultrasound Back Scatter.” B. Background Regarding Megestrol Megestrol acetate, also known as 17α-acetyloxy-6-methylpregna-4,6-diene-3,20-dione, is a synthetic progestin with progestational effects similar to those of progesterone. It is used in abortion, endometriosis, and menstrual disorders. It is also used in a variety of situations including treatment of breast cancer, contraception, and hormone replacement therapy in post-menopausal women. Megestrol acetate is also frequently prescribed as an appetite enhancer for patients in a wasting state, such as HIV wasting, cancer wasting, or anorexia. In combination with ethynyl estradiol it acts as an oral contraceptive. It is also administered to subjects after castration. Megestrol acetate is marketed by Par Pharmaceuticals, Inc. and under the brand name Megace® by Bristol Myers Squibb Co. Typical commercial formulations are relatively large volume. For example, Par Pharmaceuticals, Inc. megestrol acetate oral suspension contains 40 mg of micronized megestrol acetate per ml, and the package insert recommends an initial adult dosage of megestrol acetate oral suspension of 800 mg/day (20 mL/day). The commercial formulations of megestrol acetate are highly viscous suspensions, which have a relatively long residence time in the mouth and any tubing. Highly viscous substances are not well accepted by patient populations, particularly patients suffering wasting and those that are intubated. U.S. Pat. No. 6,028,065 for “Flocculated Suspension of Megestrol Acetate,” assigned to Pharmaceutical Resources, Inc. (Spring Valley, N.Y.), describes oral pharmaceutical micronized megestrol acetate compositions in the form of a stable flocculated suspension in water. The compositions comprise at least one compound selected from the group consisting of polyethylene glycol, propylene glycol, glycerol, and sorbitol; and a surfactant, wherein polysorbate and polyethylene glycol are not simultaneously present. U.S. Pat. No. 6,268,356, also for “Flocculated Suspension of Megestrol Acetate,” and assigned to Pharmaceutical Resources, Inc., describes methods of treating a neoplastic condition comprising administering the composition of U.S. Pat. No. 6,028,065. Another company that has developed a megestrol formulation is Eurand (Milan, Italy). Eurand's formulation is a modified form of megestrol acetate having increased bioavailability. Eurand structurally modifies poorly soluble drugs to increase their bioavailability. See www.eurand.com. For megestrol acetate, Eurand uses its' “Biorise” process, in which a New Physical Entity (NPE) is created by physically breaking down megestrol's crystal lattice. This results in drug nanocrystals and/or amorphous drug, which are then stabilized with biologically inert carriers. Eurand uses three types of carriers: swellable microparticles, composite swellable microparticles, and cyclodextrins. See e.g., http://www.eurand.com/page.php?id=39. Such a delivery system can be undesirable, as “breaking down” an active agent's crystalline structure can modify the activity of the active agent. A drug delivery system which does not alter the structure of the active agent is preferable. Among the progestins, megestrol acetate is one of the few that can be administered orally because of its reduced first-pass (hepatic) metabolism, compared to the parent hormone. In addition, it is claimed to be superior to 19-nor compounds as an antifertility agent because it has less effect on the endometrium and vagina. See Stedman 's Medical Dictionary, 25 th Ed., page 935 (Williams & Wilkins, MD 1990). There is a need in the art for megestrol formulations which exhibit increased bioavailability, less variability, and/or less viscosity as compared to conventional microparticulate megestrol formulations. The present invention satisfies these needs.
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<SOH> SUMMARY OF THE INVENTION <EOH>The invention relates to nanoparticulate megestrol compositions. The compositions comprise megestrol and preferably at least one surface stabilizer associated with the surface of the megestrol particles. The nanoparticulate megestrol particles have an effective average particle size of less than about 2000 nm. Another aspect of the invention is directed to pharmaceutical compositions comprising a nanoparticulate megestrol composition of the invention. The pharmaceutical compositions preferably comprise megestrol, at least one surface stabilizer, and a pharmaceutically acceptable carrier, as well as any desired excipients. This invention further discloses a method of making a nanoparticulate megestrol composition according to the invention. Such a method comprises contacting megestrol particles and at least one surface stabilizer for a time and under conditions sufficient to provide a nanoparticulate megestrol composition. The one or more surface stabilizers can be contacted with megestrol either before, during, or after size reduction of the megestrol. The present invention is also directed to methods of treatment using the nanoparticulate compositions of the invention for conditions such as endometriosis, dysmenorrhea, hirsutism, uterine bleeding, neoplastic diseases, methods of appetite enhancement, contraception, hormone replacement therapy, and treating patients following castration. Such methods comprises administering to a subject a therapeutically effective amount of a nanoparticulate megestrol composition according to the invention. Finally, the present invention is directed to megestrol acetate compositions with improved physical (viscosity) and pharmacokinetic profiles (such as less variability) over traditional forms of megestrol acetate. Both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. Other objects, advantages, and novel features will be readily apparent to those skilled in the art from the following detailed description of the invention.
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20040629
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20150811
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20050113
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69361.0
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SASAN, ARADHANA
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NANOPARTICULATE MEGESTROL FORMULATIONS
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UNDISCOUNTED
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CONT-ACCEPTED
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10,878,632
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ACCEPTED
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Tetracyclic compounds as c-Met inhibitors
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The present invention relates to compounds of the Formulae (I) and (II), wherein R1—R10 and G are defined herein, and their pharmaceutically acceptable salts. These compounds modulate the activity of c-Met and are therefore expected to be useful in the prevention and treatment of c-Met related disorders such as cancer.
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1. A compound of the formula I: wherein: R1 is an aryl or heteroaryl group, wherein said aryl or heteroaryl group is unsubstituted or optionally substituted with one or more substituents selected from the group consisting of halogen, —OH, —OR8, —COR8, —COOR8,—CONR8R9, —NR8R9, —CN, —NO2, —S(O)2R8, —SO2NR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl and aryl; each R2 and R3 is independently selected from the group consisting of hydrogen, halogen, —OH, —OR7, —NR7R8, —CN, —COR8, —COOR8, —CONR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl and alkynyl; or R2 and R3, together with the carbon atom to which they are attached can form a cycloalkyl or heterocycle; R4, R5, R6, and R7 are independently selected from the group consisting of hydrogen, halogen, —OR8, —COR6, —COOR8, —CONR8R9, —NR8R9, —CN, —NO2, —S(O)nR8 (wherein n is 0, 1 or 2), —SO2R7R8, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl, and aryl; and each R8 and R9 is independently selected from the group consisting of hydrogen, lower alkyl, cycloalkyl, heterocycle, alikenyl, alkynyl, aryl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl or R8 and R9 together with the atom to which they are attached form a heteroalicyclic ring optionally substituted with a group selected from the group consisting of alkyl, —OH and amino; and p is 1, 2, 3, 4 or 5, it being understood that when p is an integer greater than 1, the R2 and R3 groups on each carbon atom may be the same as or different from the R2 and R3 groups on any adjacent carbon atom; or a pharmaceutically acceptable salt thereof. 2. The compound of claim 1, wherein p is 1. 3. The compound of claim 1, wherein R1 is phenyl. 4. The compound of claim 3, wherein said phenyl group is substituted with an —OH or a halo group. 5. A compound of formula II: wherein: each R10 is independently seleted from the group consisting of halogen, —OH, —OR8, —COR8, —COOR8, —CONR8 R9, —NR8R9, —CN, —NO2, —S(O)2R8, —SO2NR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl and aryl; q is 1, 2, 3, 4 or5; G is nitrogen or carbon; each R2 and R3 is independently selected from the group consisting of hydrogen, halogen, —OH, —OR7, —NR7R8, —CN, —COR8, —COOR8, —CONR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl and alkynyl; or R2 and R3, together with the carbon atom to which they are attached can form a cycloalkyl or heterocycle; R4, R5, R6, and R7 are independently selected from the group consisting of hydrogen, halogen, —OR8, —COR8, —COOR8, —CONR8R9, —NR8R9, —CN, —NO2, —S(O)nR8 (wherein n is 0, 1, or 2), —SO2R8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl, and aryl; and R8 and R9 are selected from the group consisting of hydrogen, lower alkyl, cycloalkyl, heterocycle, allkenyl, alkynyl, aryl, aminoalkyl, alkylaminoalkyl, and dialkylaminoalkyl or R8 and R9 together with the atom to which they are attached form a heteroalicyclic ring optionally substituted with a group selected from the group consisting of alkyl, —OH and amino; and p is 1, 2, 3, 4 or 5, it being understood that when p is an integer greater than 1, the R2 and R3 groups on each carbon atom may be the same as or different from the R2 and R3 groups on any adjacent carbon atom; or a pharmaceutically acceptable salt thereof. 6. The compound of claim 5, wherein the variable p is 1. 7. The compound of claim 5, wherein R10 is —OH or halo and q is 1. 8. The compound of claim 5, wherein the variable G is nitrogen. 9. A compound selected from the group consisting of: a pharmaceutically acceptable salt thereof. 10. A compound which is: 11. A method for treating a c-Met related disorder comprising administering to a subject suffering from a c-Met related disorder a therapeutically effective amount of a compound of claim 1. 12. The method of claim 11, wherein said c-Met related disorder is a cancer. 13. The method of claim 12, wherein said cancer is selected from the group consisting of breast cancer, lung cancer, colorectal cancer, prostate cancer, pancreatic cancer, glioma, liver cancer, gastric cancer, head cancer, neck cancer, melanoma, renal cancer, leukemia, myeloma, and sarcoma. 14. A pharmaceutical composition comprising a compound of claim 1, or pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient.
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This application claims the benefit of U.S. Provisional Application Ser. No. 60/484,222, filed Jul. 2, 2003, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION The following is offered as background information only and is not admitted to be prior art to the present invention. Protein kinases (“PKs”) are enzymes that catalyze the phosphorylation of hydroxy groups on tyrosine, serine and threonine residues of proteins. The consequences of this seemingly simple activity are staggering; cell growth, differentiation and proliferation, i.e., virtually all aspects of cell life in one way or another depend on PK activity. Furthermore, abnormal PK activity has been related to a host of disorders, ranging from relatively non-life threatening diseases such as psoriasis to extremely virulent diseases such as glioblastoma (brain cancer). The PKs can be conveniently broken down into two classes, the protein tyrosine kinases (PTKs) and the serine-threonine kinases (STKs). One of the prime aspects of PTK activity is their involvement with growth factor receptors. Growth factor receptors are cell-surface proteins. When bound by a growth factor ligand, growth factor receptors are converted to an active form which interacts with proteins on the inner surface of a cell membrane. This leads to phosphorylation on tyrosine residues of the receptor and other proteins and to the formation inside the cell of complexes with a variety of cytoplasmic signaling molecules that, in turn, effect numerous cellular responses such as cell division (proliferation), cell differentiation, cell growth, expression of metabolic effects to the extracellular microenvironment, etc. For a more complete discussion, see Schlessinger and Ullrich, Neuron 9:303-391 (1992), which is incorporated by reference, including any drawings, as if fully set forth herein. Growth factor receptors with PTK activity are known as receptor tyrosine kinases (“RTKs”). They comprise a large family of transmembrane receptors with diverse biological activity. At present, at least nineteen (19) distinct subfamilies of RTKs have been identified. An example of these is the subfamily designated the “HER” RTKs, which include EGFR (epithelial growth factor receptor), HER2, HER3 and HER4. These RTKs consist of an extracellular glycosylated ligand binding domain, a transmembrane domain and an intracellular cytoplasmic catalytic domain that can phosphorylate tyrosine residues on proteins. Another RTK subfamily consists of insulin receptor (IR), insulin-like growth factor I receptor (IGF-1R) and insulin receptor related receptor (IRR). IR and IGF-1R interact with insulin, IGF-I and IGF-II to form a heterotetramer of two entirely extracellular glycosylated subunits and two subunits which cross the cell membrane and which contain the tyrosine kinase domain. A third RTK subfamily is referred to as the platelet derived growth factor receptor (“PDGFR”) group, which includes PDGFR, CSFIR, c-kit and c-fms. These receptors consist of glycosylated extracellular domains composed of variable numbers of immunoglobin-like loops and an intracellular domain wherein the tyrosine kinase domain is interrupted by unrelated amino acid sequences. Another group which, because of its similarity to the PDGFR subfamily, is sometimes subsumed into the later group is the fetus liver kinase (“flk”) receptor subfamily. This group is believed to be made of up of kinase insert domain-receptor fetal liver kinase-1 (KDR/FLK-1), flk-1R, flk-4 and fms-like tyrosine kinase 1 (flt-1). Still another member of the growth factor receptor family is the vascular endothelial growth factor (“VEGF”) receptor subgroup. VEGF is a dimeric glycoprotein similar to PDGF but has different biological functions and target cell specificity in vivo. In particular, VEGF is presently thought to play an essential role is vasculogenesis and angiogenesis. A further member of the tyrosine kinase growth factor receptor family is the fibroblast growth factor (“FGF”) receptor subgroup. This group consists of four receptors, FGFR1-4, and seven ligands, FGF1-7. While not yet well defined, it appears that the receptors consist of a glycosylated extracellular domain containing a variable number of immunoglobin-like loops and an intracellular domain in which the tyrosine kinase sequence is interrupted by regions of unrelated amino acid sequences. Still another member of the tyrosine kinase growth factor receptor family is MET, often referred to as c-Met. c-met is also known as hepatocyte growth factor receptor or scatter factor receptor. c-Met is thought to play a role in primary tumor growth and metastasis. A more complete listing of the known RTK subfamilies is described in Plowman et al., DN&P, 7(6):334-339 (1994), which is incorporated by reference, including any drawings, as if fully set forth herein. In addition to the RTKs, there also exists a family of entirely intracellular PTKs called “non-receptor tyrosine kinases” or “cellular tyrosine kinases.” This latter designation, abbreviated “CTK,” will be used herein. CTKs do not contain extracellular and transmembrane domains. At present, over 24 CTKs in 11 subfamilies (Src, Frk, Btk, Csk, Abl, Zap70, Fes, Fps, Fak, Jak and Ack) have been identified. The Src subfamily appear so far to be the largest group of CTKs and includes Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk. For a more detailed discussion of CTKs, see Bolen, Oncogene, 8:2025-2031 (1993), which is incorporated by reference, including any drawings, as if fully set forth herein. The serine/threonine kinases, STKs, like the CTKs, are predominantly intracellular although there are a few receptor kinases of the STK type. STKs are the most common of the cytosolic kinases; i.e., kinases that perform their function in that part of the cytoplasm other than the cytoplasmic organelles and cytoskelton. The cytosol is the region within the cell where much of the cell's intermediary metabolic and biosynthetic activity occurs; e.g., it is in the cytosol that proteins are synthesized on ribosomes. RTKs, CTKs and STKs have all been implicated in a host of pathogenic conditions including, significantly, cancer. Other pathogenic conditions which have been associated with PTKs include, without limitation, psoriasis, hepatic cirrhosis, diabetes, angiogenesis, restenosis, ocular diseases, rheumatoid arthritis and other inflammatory disorders, immunological disorders such as autoimmune disease, cardiovascular disease such as atherosclerosis and a variety of renal disorders. With regard to cancer, two of the major hypotheses advanced to explain the excessive cellular proliferation that drives tumor development relate to functions known to be PK regulated. That is, it has been suggested that malignant cell growth results from a breakdown in the mechanisms that control cell division and/or differentiation. It has been shown that the protein products of a number of proto-oncogenes are involved in the signal transduction pathways that regulate cell growth and differentiation. These protein products of proto-oncogenes include the extracellular growth factors, transmembrane growth factor PTK receptors (RTKs), cytoplasmic PTKs (CTKs) and cytosolic STKs, discussed above. In view of the apparent link between PK-related cellular activities and wide variety of human disorders, it is no surprise that a great deal of effort is being expended in an attempt to identify ways to modulate PK activity. Some of these have involved biomimetic approaches using large molecules patterned on those involved in the actual cellular processes (e.g., mutant ligands (U.S. application Ser. No. 4,966,849); soluble receptors and antibodies (Application No. WO 94/10202, Kendall and Thomas, Proc. Nat'l Acad. Sci., 90:10705-10709 (1994), Kim, et al., Nature, 362:841-844 (1993)); RNA ligands (Jelinek, et al., Biochemistry, 33: 10450-56); Takano, et al., Mol. Bio. Cell, 4:358A (1993); Kinsella, et al., Exp. Cell Res., 199: 56-62 (1992); Wright, et al., J. Cellular Phys., 152:448-57) and tyrosine kinase inhibitors (WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., Proc. Am. Assoc. Cancer Res., 35:2268 (1994)). In addition to the above, attempts have been made to identify small molecules which act as PK inhibitors. For example, bis-monocylic, bicyclic and heterocyclic aryl compounds (PCT WO 92/20642), vinylene-azaindole derivatives (PCT WO 94/14808) and 1-cyclopropyl-4-pyridylquinolones (U.S. Pat. No. 5,330,992) have been described as tyrosine kinase inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), quinazoline derivatives (EP Application No. 0 566 266 A1), selenaindoles and selenides (PCT WO 94/03427), tricyclic polyhydroxylic compounds (PCT WO 92/21660) and benzylphosphonic acid compounds (PCT WO 91/15495) have all been described as PTK inhibitors useful in the treatment of cancer. SUMMARY OF THE INVENTION The invention relates to a compound of the formula I: wherein: R1 is an aryl or heteroaryl group, wherein said aryl or heteroaryl group is unsubstituted or optionally substituted with one or more substituents selected from the group consisting of halogen, —OH, —OR8, —COR8, —COOR8, —CONR8R9, —NR8R9, —CN, —NO2, —S(O)2R8, —SO2NR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl and aryl; each R2 and R3 is independently selected from the group consisting of hydrogen, halogen, —OH, —OR7, —NR7R8, —CN, —COR8, —COOR8, —CONR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl and alkynyl; or R2 and R3, together with the carbon atom to which they are attached can form a cycloalkyl or heterocycle; R4, R5, R6, and R7 are independently selected from the group consisting of hydrogen, halogen, —OR8, —COR8, —COOR8, —CONR8R9, —NR8R9, —CN, —NO2, —S(O)nR6 (wherein n is 0, 1 or 2), —SO2R7R8, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl, and aryl; and each R8 and R9 is independently selected from the group consisting of hydrogen, lower alkyl, cycloalkyl, heterocycle, allkenyl, alkynyl, aryl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl or R8 and R9 together with the atom to which they are attached form a heteroalicyclic ring optionally substituted with a group selected from the group consisting of alkyl, —OH and amino; and p is 1, 2, 3, 4 or 5, it being understood that when p is an integer greater than 1, the R2 and R3 groups on each carbon atom may be the same as or different from the R2 and R3 groups on any adjacent carbon atom; or a pharmaceutically acceptable salt thereof. In a preferred embodiment, the variable p in a compound of formula I is 1. In another preferred embodiment, the aryl group on the compound of formula I is phenyl. In still another preferred embodiment the aryl group on the compound of formula I is a phenyl group substituted with an —OH or a halo group. The invention further relates to a compound of formula II: wherein: each R10 is independently selected from the group consisting of halogen, —OH, —OR8, —COR8, —COOR8, —CONR8R9, —NR8R9, —CN, —NO2, —S(O)2R8, —SO2NR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl and aryl; q is 1, 2, 3, 4 or 5; G is nitrogen or carbon; each R2 and R3 is independently selected from the group consisting of hydrogen, halogen, —OH, —OR7, —NR7R8, —CN, —COR8, —COOR8, —CONR8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl and alkynyl; or R2 and R3, together with the carbon atom to which they are attached can form a cycloalkyl or heterocycle; R4, R5, R6, and R7 are independently selected from the group consisting of hydrogen, halogen, —OR8, —COR8, —COOR8, —CONR8R9, —NR8R9, —CN, —NO2, —S(O)nR8 (wherein n is 0, 1 or 2), —SO2R8R9, —CF3, lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl, and aryl; and R8 and R9 are selected from the group consisting of hydrogen, lower alkyl, cycloalkyl, heterocycle, allkenyl, alkynyl, aryl, aminoalkyl, alkylaminoalkyl, and dialkylaminoalkyl or R8 and R9 together with the atom to which they are attached form a heteroalicyclic ring optionally substituted with a group selected from the group consisting of alkyl, —OH and amino; and p is 1, 2, 3, 4 or 5, it being understood that when p is an integer greater than 1, the R2 and R3 groups on each carbon atom may be the same as or different from the R2 and R3 groups on any adjacent carbon atom; or a pharmaceutically acceptable salt thereof. In a preferred embodiment, the variable p in the compound of formula II is 1. In another preferred embodiment, R10 in the compound of formula II is —OH or halo and q is 1. In still another preferred embodiment, the variable G in the compound of formula II is nitrogen. In yet another preferred embodiment, the compound of formula I or II is a compound selected from the group consisting of: a pharmaceutically acceptable salt thereof. In still another preferred embodiment, the compound of formula I or II is: The invention further relates to a method for treating a c-Met related disorder with a compound of formula I or II. In a preferred embodiment, the c-Met related disorder is a cancer. In another preferred embodiment, the cancer is selected from the group consisting of breast cancer, lung cancer, colorectal cancer, prostate cancer, pancreatic cancer, glioma, liver cancer, gastric cancer, head cancer, neck cancer, melanoma, renal cancer, leukemia, myeloma, and sarcoma. The invention still further relates to a pharmaceutical composition comprising a compound of formula I or II or pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A family of novel tetracyclic compounds have been discovered which exhibit c-Met modulating ability and have a ameliorating effect against disorders related to abnormal c-Met activity. c-Met is an attractive target from a clinical perspective because: 1) c-Met has been implicated in the growth and metastases of most types of cancer; 2) growth at the secondary site appears to be the rate-limiting step in metastasis; and 3) by the time of diagnosis, it is likely that the disease has already spread. c-Met is a receptor tyrosine kinase that is encoded by the Met protooncogene and transduces the biological effects of hepatocyte growth factor (HGF), which is also referred to as scatter factor (SF). Jiang et al., Crit. Rev. Oncol. Hematol. 29: 209-248 (1999). c-Met and HGF are expressed in numerous tissues, although their expression is normally confined predominantly to cells of epithelial and mesenchymal origin, respectively. c-Met and HGF are required for normal mammalian development and have been shown to be important in cell migration, cell proliferation and survival, morphogenic differentiation, and organization of 3-dimensional tubular structures (e.g., renal tubular cells, gland formation, etc.). It is proposed that c-Met-dependent tumor growth, invasion, and dissemination is mediated by these cellular actions. In addition to its effects on epithelial cells, HGF/SF has been reported to be an angiogenic factor, and c-Met signaling in endothelial cells can induce many of the cellular responses necessary for angiogenesis (proliferation, motility, invasion). The c-Met receptor has been shown to be expressed in a number of human cancers. c-Met and its ligand, HGF, have also been shown to be co-expressed at elevated levels in a variety of human cancers (particularly sarcomas). However, because the receptor and ligand are usually expressed by different cell types, c-Met signaling is most commonly regulated by tumor-stroma (tumor-host) interactions. Furthermore, c-Met gene amplification, mutation, and rearrangement have been observed in a subset of human cancers. Families with germline mutations that activate c-Met kinase are prone to multiple kidney tumors as well as tumors in other tissues. Numerous studies have correlated the expression of c-Met and/or HGF/SF with the state of disease progression of different types of cancer (including lung, colon, breast, prostate, liver, pancreas, brain, kidney, ovaries, stomach, skin, and bone cancers). Furthermore, the overexpression of c-Met or HGF have been shown to correlate with poor prognosis and disease outcome in a number of major human cancers including lung, liver, gastric, and breast. The strong correlation of c-Met with the biology of metastasis and invasion and disease pathogenesis comprises a novel mechanism for treatment of metastatic cancers. c-Met has been directly implicated in cancers without a successful treatment regimen such as pancreatic cancer, glioma, and hepatocellular carcinoma. A c-Met kinase inhibitor could fill an unmet medical need in the treatment of these cancers. These observations suggest that c-Met kinase inhibitors would be an effective treatment for primary tumors that are driven by c-Met, but more importantly, would prevent disseminated micrometastases from growing into life-threatening metastases. Therefore, the utility of a c-Met inhibitor extends to preventative and adjuvant therapy settings. In addition, certain cancers (e.g., papillary renal cell carcinoma, some gastric and lung cancers) can be treated which are believed to be driven by c-Met mutation/genetic alteration and dependent on c-Met for growth and survival. These cancers are expected to be sensitive to treatment. Various human cancers are the primary target indication for c-Met antagonists. These cancers include major cancers such as breast, lung, colorectal, prostate; as well as pancreatic cancer, glioma, liver cancer, gastric cancer, head and neck cancers, melanoma, renal cancer, leukemias, myeloma, and sarcomas. The compounds presented herein are exemplary only and are not to be construed as limiting the scope of this invention in any manner. In one aspect, this invention is directed to a pharmaceutical composition comprising one or more compounds of Formula (I) and (II) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable excipient. It is also an aspect of this invention that a compound described herein, or its salt, might be combined with other chemotherapeutic agents for the treatment of the diseases and disorders discussed above. For instance, a compound or salt of this invention might be combined with alkylating agents such as fluorouracil (5-FU) alone or in further combination with leukovorin; or other alkylating agents such as, without limitation, other pyrimidine analogs such as UFT, capecitabine, gemcitabine and cytarabine, the alkyl sulfonates, e.g., busulfan (used in the treatment of chronic granulocytic leukemia), improsulfan and piposulfan; aziridines, e.g., benzodepa, carboquone, meturedepa and uredepa; ethyleneimines and methylmelamines, e.g., altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylolmelamine; and the nitrogen mustards, e.g., chlorambucil (used in the treatment of chronic lymphocytic leukemia, primary macroglobulinemia and non-Hodgkin's lymphoma), cyclophosphamide (used in the treatment of Hodgkin's disease, multiple myeloma, neuroblastoma, breast cancer, ovarian cancer, lung cancer, Wilm's tumor and rhabdomyosarcoma), estramustine, ifosfamide, novembrichin, prednimustine and uracil mustard (used in the treatment of primary thrombocytosis, non-Hodgkin's lymphoma, Hodgkin's disease and ovarian cancer); and triazines, e.g., dacarbazine (used in the treatment of soft tissue sarcoma). Likewise a compound or salt of this invention might be expected to have a beneficial effect in combination with other antimetabolite chemotherapeutic agents such as, without limitation, folic acid analogs, e.g. methotrexate (used in the treatment of acute lymphocytic leukemia, choriocarcinoma, mycosis fungiodes breast cancer, head and neck cancer and osteogenic sarcoma) and pteropterin; and the purine analogs such as mercaptopurine and thioguanine which find use in the treatment of acute granulocytic, acute lymphocytic and chronic granulocytic leukemias. A compound or salt of this invention might also be expected to prove efficacious in combination with natural product based chemotherapeutic agents such as, without limitation, the vinca alkaloids, e.g., vinblastin (used in the treatment of breast and testicular cancer), vincristine and vindesine; the epipodophylotoxins, e.g., etoposide and teniposide, both of which are useful in the treatment of testicular cancer and Kaposi's sarcoma; the antibiotic chemotherapeutic agents, e.g., daunorubicin, doxorubicin, epirubicin, mitomycin (used to treat stomach, cervix, colon, breast, bladder and pancreatic cancer), dactinomycin, temozolomide, plicamycin, bleomycin (used in the treatment of skin, esophagus and genitourinary tract cancer); and the enzymatic chemotherapeutic agents such as L-asparaginase. In addition to the above, a compound or salt of this invention might be expected to have a beneficial effect used in combination with the platinum coordination complexes (cisplatin, etc.); substituted ureas such as hydroxyurea; methylhydrazine derivatives, e.g., procarbazine; adrenocortical suppressants, e.g., mitotane, aminoglutethimide; and hormone and hormone antagonists such as the adrenocorticosteriods (e.g., prednisone), progestins (e.g.; hydroxyprogesterone caproate); estrogens (e.g., diethylstilbesterol); antiestrogens such as tamoxifen; androgens, e.g., testosterone propionate; and aromatase inhibitors (such as anastrozole. Finally, the combination of a compound of this invention might be expected to be particularly effective in combination with mitoxantrone or paclitaxel for the treatment of solid tumor cancers or leukemias such as, without limitation, acute myelogenous (non-lymphocytic) leukemia. The above method can be carried out in combination with a chemotherapeutic agent selected from the group consisting of mitotic inhibitors, alkylating agents, antimetabolites, cell cycle inhibitors, enzymes, topoisomerase inhibitors, biological response modifiers, anti-hormones, antiangiogenic agents such as MMP-2, MMP-9 and COX-2 inhibitors, and anti-androgens. Examples of useful COX-II inhibitors include Vioxx™, CELEBREX™ (alecoxib), valdecoxib, paracoxib, rofecoxib, and Cox 189. Examples of useful matrix metalloproteinase inhibitors are described in WO 96/33172 (published Oct. 24, 1996), WO 96/27583 (published Mar. 7, 1996), European Patent Application No. 97304971.1 (filed Jul. 8, 1997), European Patent Application No. 99308617.2 (filed Oct. 29, 1999), WO 98/07697 (published Feb. 26, 1998), WO 98/03516 (published Jan. 29, 1998), WO 98/34918 (published Aug. 13, 1998), WO 98/34915 (published Aug. 13, 1998), WO 98/33768 (published Aug. 6, 1998), WO 98/30566 (published Jul. 16, 1998), European Patent Publication 606,046 (published Jul. 13, 1994), European Patent Publication 931,788 (published Jul. 28, 1999), WO 90/05719 (published May 31, 1990), WO 99/52910 (published Oct. 21, 1999), WO 99/52889 (published Oct. 21, 1999), WO 99/29667 (published Jun. 17, 1999), PCT International Application No. PCT/IB98/01113 (filed Jul. 21, 1998), European Patent Application No. 99302232.1 (filed Mar. 25, 1999), Great Britain patent application number 9912961.1 (filed Jun. 3, 1999), U.S. Provisional Application No. 60/148,464 (filed Aug. 12, 1999), U.S. Pat. No. 5,863,949 (issued Jan. 26, 1999), U.S. Pat. No. 5,861,510 (issued Jan. 19, 1999), and European Patent Publication 780,386 (published Jun. 25, 1997), all of which are incorporated herein in their entireties by reference. Preferred MMP-2 and MMP-9 inhibitors are those that have little or no activity inhibiting MMP-1. More preferred, are those that selectively inhibit MMP-2 and/or MMP-9 relative to the other matrix-metalloproteinases (i.e. MMP-1, MMP-3, MMP-4, MMP-5, MMP-6, MMP-7, MMP-8, MMP-10, MMP-11, MMP-12, and MMP-13). Some specific examples of MMP inhibitors useful in the present invention are AG-3340, RO 32-3555, RS 13-0830, and the compounds recited in the following list: 3-[[4-(4-fluoro-phenoxy)-benzenesulfonyl]-(1-hydroxycarbamoyl-cyclopentyl)- amino]-propionic acid; 3-exo-3-[4-(4-fluoro-phenoxy)-benzenesulfonylamino]-8-oxa-bicyclo[3.2.1]octane-3-carboxylic acid hydroxyamide; (2R, 3R) 1-[4- (2-chloro-4-fluoro-benzyloxy)-benzenesulfonyl]-3-hydroxy-3-methyl-pip eridine-2-carboxylic acid hydroxyamide; 4-[4-(4-fluoro-phenoxy)-benzenesulfonylamino]-tetrahydro-pyran-4-carboxylic acid hydroxyamide; 3-[[4-(4-fluoro-phenoxy)-benzenesulfonyl]-(1-hydroxycarbamoyl-cyclobutyl)-a mino]-propionic acid; 4-[4-(4-chloro-phenoxy)-benzenesulfonylam ino]-tetrahydro-pyran-4-carboxylic acid hydroxyamide; (R) 3-[4-(4-chloro-phenoxy)-benzenesulfonylamino]-tetrahydro-pyran-3-carboxylic acid hydroxyamide; (2R, 3R) 1-[4-(4-fluoro-2-methyl-benzyloxy)-benzenesulfonyl]-3-hydroxy-3-methyl-piperidine-2-carboxylic acid hydroxyamide; 3-[[(4-(4-fluoro-phenoxy)-benxenesulfonyl]-(1-hydroxycarbamoyl-1-methyl-ethyl)-amino]-propionic acid; 3-[[4-(4-fluoro-phenoxy)-benzenesulfonyl]-(4-hydroxycarbamoyl-tetrahydro-py ran-4-yl)-amino]-propionic acid; 3-exo-3-[4-(4-chloro-phenoxy)-benzenesulfonylamino]-8-oxa-bicyclo[3.2.1]octane-3-carboxylic acid hydroxyamide; 3-endo-3-[4-(4-fluoro-phenoxy)-benzenesulfonylamino]-8-oxa-bicyclo [3.2.1]octane-3-carboxylic acid hydroxyamide; and (R) 3-[4-(4-fluoro-phenoxy)-benzenesulfonylamino]-tetrahydro-furan-3-carboxyli c acid hydroxyamide; and pharmaceutically acceptable salts and solvates of said compounds. Other anti-angiogenesis agents, including other COX-II inhibitors and other MMP inhibitors, can also be used in the present invention. Compounds of the Formulae (I) and (II) can also be used with signal transduction inhibitors, such as agents that can inhibit EGFR (epidermal growth factor receptor) responses, such as EGFR antibodies, EGF antibodies, and molecules that are EGFR inhibitors; VEGF (vascular endothelial growth factor) inhibitors; and erbB2 receptor inhibitors, such as organic molecules or antibodies that bind to the erbB2 receptor, for example, HERCEPTIN.™. (Genentech, Inc. of South San Francisco, Calif., USA). EGFR inhibitors are described in, for example in WO 95/19970 (published Jul. 27, 1995), WO 98/14451 (published Apr. 9, 1998), WO 98/02434 (published Jan. 22, 1998), and U.S. Pat. No. 5,747,498 (issued May 5, 1998), and such substances can be used in the present invention as described herein. EGFR-inhibiting agents include, but are not limited to, the monoclonal antibodies C225 and anti-EGFR 22Mab (ImClone Systems Incorporated of New York, N.Y., USA), the compounds ZD-1839 (AstraZeneca), BIBX-1382 (Boehringer Ingelheim), MDX-447 (Medarex Inc. of Annandale, N.J., USA), and OLX-103 (Merck & Co. of Whitehouse Station, N.J., USA), VRCTC-310 (Ventech Research) and EGF fusion toxin (Seragen Inc. of Hopkinton, Mass.). These and other EGFR-inhibiting agents can be used in the present invention. VEGF inhibitors, for example SU-5416, SU 11248, SU-6668 (Sugen Inc. of South San Francisco, Calif., USA), can also be combined with a compound of the Formulae (I) and (II). VEGF inhibitors are described in, for example in WO 99/24440 (published May 20, 1999), PCT International Application PCT/IB99/00797 (filed May 3, 1999), in WO 95/21613 (published Aug. 17, 1995), WO 99/61422 (published Dec. 2, 1999), U.S. Pat. No. 5,834,504 (issued Nov. 10, 1998), WO 01/60814,WO 98/50356 (published Nov. 12, 1998), U.S. Pat. No. 5,883,113 (issued Mar. 16, 1999), U.S. Pat. No. 5,886,020 (issued Mar. 23, 1999), U.S. Pat. No. 5,792,783 (issued Aug. 11, 1998), WO 99/10349 (published Mar. 4, 1999), WO 97/32856 (published Sep. 12, 1997), WO 97/22596 (published Jun.26, 1997), WO 98/54093 (published Dec. 3, 1998), WO 98/02438 (published Jan. 22, 1998), WO 99/16755 (published Apr. 8, 1999), and WO 98/02437 (published Jan. 22, 1998), all of which are incorporated herein in their entireties by reference. Other examples of some specific VEGF inhibitors useful in the present invention are IM862 (Cytran Inc. of Kirkland, Wash., USA); anti-VEGF monoclonal antibody of Genentech, Inc. of South San Francisco, Calif.; and angiozyme, a synthetic ribozyme from Ribozyme (Boulder, Colo.) and Chiron (Emeryville, Calif.). These and other VEGF inhibitors can be used in the present invention as described herein. ErbB2 receptor inhibitors, such as GW-282974 (Glaxo Wellcome plc), and the monoclonal antibodies AR-209 (Aronex Pharmaceuticals Inc. of TheWoodlands, Tex., USA) and 2B-1 (Chiron), can furthermore be combined with a compound of the Formula (I) or (II), for example those indicated in WO 98/02434 (published Jan. 22, 1998), WO 99/35146 (published Jul. 15, 1999), WO 99/35132 (published Jul. 15, 1999), WO 98/02437 (published Jan. 22, 1998), WO 97/13760 (published Apr. 17, 1997), WO 95/19970 (published Jul. 27, 1995), U.S. Pat. No. 5,587,458 (issued Dec. 24, 1996), and U.S. Pat. No. 5,877,305 (issued Mar. 2, 1999), which are all hereby incorporated herein in their entireties by reference. ErbB2 receptor inhibitors useful in the present invention are also described in U.S. Provisional Application No. 60/117,341, filed Jan. 27, 1999, and in U.S. Provisional Application No. 60/117,346, filed Jan. 27, 1999, both of which are incorporated in their entireties herein by reference. The erbB2 receptor inhibitor compounds and substance described in the aforementioned PCT applications, U.S. patents, and U.S. provisional applications, as well as other compounds and substances that inhibit the erbB2 receptor, can be used with compounds of the Formulae (I) and (II), in accordance with the present invention. Compounds of the Formula (I) and (II) can also be used with other agents useful in treating cancer, including, but not limited to, agents capable of enhancing antitumor immune responses, such as CTLA4 (cytotoxic lymphocite antigen 4) antibodies, and other agents capable of blocking CTLA4; and anti-proliferative agents such as other farnesyl protein transferase inhibitors, for example the farnesyl protein transferase inhibitors described in the references cited in the “Background” section, of U.S. Pat. No., 6,258,824 B1. Specific CTLA4 antibodies that can be used in the present invention include those described in U.S. Provisional Application 60/113,647 (filed Dec. 23, 1998) which is incorporated by reference in its entirety, however other CTLA4 antibodies can be used in the present invention. The above method can be also be carried out in combination with radiation therapy, wherein the amount of a compound of the Formula (I) and (II), in combination with the radiation therapy, is effective in treating the above diseases. The level of radiation therapy administered may be reduced to a sub-efficacy dose when administered in combination with the compounds of the preferred embodiments of the present invention. Techniques for administering radiation therapy are known in the art, and these techniques can be used in the combination therapy described herein. The administration of the compound of the invention in this combination therapy can be determined as described herein. Another aspect of the invention is directed ot the use of compounds of the Formulae (I) and (II) in the preparation of a medicament, which is useful in the treatment of a disease mediated by abnormal Met kinase activity. “Pharmaceutically acceptable salt” or “pharmaceutically acceptable salt thereof” refer to those salts which retain the biological effectiveness and properties of the free bases and which are obtained by reaction with inorganic or organic acids, such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, acetic acid, benzenesulfonic acid (besylate), benzoic acid, camphorsulfonic acid, citric acid, fumaric acid, gluconic acid, glutamic acid, isethionic acid, lactic acid, maleic acid, malic acid, mandelic acid, mucic acid, pamoic acid, pantothenic acid, succinic acid, tartaric acid, and the like. A “pharmaceutical composition” refers to a mixture of one or more of the compounds described herein, or physiologically acceptable salts thereof, with other chemical components, such as physiologically acceptable carriers and excipients. The purpose of a pharmaceutical composition is to facilitate administration of a compound to an organism. As used herein, a “physiologically acceptable carrier” refers to a carrier or diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the administered compound. An “excipient” refers to an inert substance added to a pharmaceutical composition to further facilitate administration of a compound. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives (including microcrystalline cellulose), gelatin, vegetable oils, polyethylene glycols, diluents, granulating agents, lubricants, binders, disintegrating agents, and the like. “Alkyl” refers to a saturated aliphatic hydrocarbon including straight chain, branched chain or cyclic groups. Preferably, the alkyl group has 1 to 20 carbon atoms (whenever a numerical range; e.g., “1-20”, is stated herein, it means that the group, in this case the alkyl group, may contain 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkyl having 1 to 10 carbon atoms. Most preferably, it is a lower alkyl having 1 to 4 carbon atoms. The alkyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO2, —CZ3, —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. R and R′ are independently H, alkyl, or aryl, wherein alkyl or aryl may be further substituted with halogen, (CH2)nN(R″)2, (CH2)nCO2R″, (CH2)nOR″, (CH2)nOC(O)R′, alkoxycarbonyl, aryloxycarbonyl, aminocarbonyl, a heteroalicyclic ring, aryl, alkoxy, —OCZ3, aryloxy, C(O)NH2 or heteroaryl. R′ is H, alkyl or aryl. n is 0-3. “Alkenyl” refers to an aliphatic hydrocarbon having at least one carbon-carbon double bond, including straight chain, branched chain or cyclic groups having at least one carbon-carbon double bond. Preferably, the alkenyl group has 2 to 20 carbon atoms (whenever a numerical range; e.g., “2-20”, is stated herein, it means that the group, in this case the alkenyl group, may contain 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkenyl having 2 to 10 carbon atoms. Most preferably, it is a lower alkenyl having 2 to 6 carbon atoms. The alkenyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO 2, —CZ3 , —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. Wherein R and R′ are defined herein. “Alkynyl” refers to an aliphatic hydrocarbon having at least one carbon-carbon triple bond, including straight chain, branched chain or cyclic groups having at least one carbon-carbon triple bond. Preferably, the alkenyl group has 2 to 20 carbon atoms (whenever a numerical range; e.g., “2-20”, is stated herein, it means that the group, in this case the alkynyl group, may contain 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkynyl having 2 to 10 carbon atoms. Most preferably, it is a lower alkynyl having 2 to 6 carbon atoms. The alkynyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO2, —CZ3, —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. Wherein R and R′ are defined herein. A “cycloalkyl” or an “alicyclic” group refers to an all-carbon monocyclic or fused ring (i.e., rings which share an adjacent pair of carbon atoms) group wherein one or more of the rings does not have a completely conjugated pi-electron system. Examples, without limitation, of cycloalkyl groups are cyclopropane, cyclobutane, cyclopentane, cyclopentene, cyclohexane, adamantane, cyclohexadiene, cycloheptane and, cycloheptatriene. A cycloalkyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO2, —CZ3, —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. Wherein R and R′ are defined herein. An “aryl” group refers to an all-carbon monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups having a completely conjugated pi-electron system. Examples, without limitation, of aryl groups are phenyl, naphthalenyl and anthracenyl. The aryl group may be substituted or unsubstituted. When substituted, each substituted group is preferably one or more selected halogen, hydroxy, alkoxy, aryloxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO2, —CZ3, —OCZ3, —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. Wherein R and R′ are defined herein. As used herein, a “heteroaryl” group refers to a monocyclic or fused ring (i.e., rings which share an adjacent pair of atoms) group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur and, in addition, having a completely conjugated pi-electron system. Examples, without limitation, of heteroaryl groups are pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline, purine and carbazole. The heteroaryl group may be substituted or unsubstituted. When substituted, each substituted group is preferably one or more selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO2, —CZ3, —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, where Z is halogen. Wherein R and R′ are defined herein. A “heteroalicyclic ring” or “heteroalicycle” group refers to a monocyclic or fused ring group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur. The rings may also have one or more double bonds. However, the rings may not have a completely conjugated pi-electron system. The heteroalicyclic ring may be substituted or unsubstituted. The heteroalicyclic ring may contain one or more oxo groups. When substituted, the substituted group(s) is preferably one or more selected halogen, hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO2, —CZ3, —SR′, —SOR′, —SO2R′, —SO2OR′, —SO2NRR′, thiocarbonyl, —RNSO2R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. Wherein R and R′ are defined herein. Z refers to a halogen group selected from the group consisting of fluorine, chlorine, bromine and iodine. A “hydroxy” group refers to an —OH group. An “alkoxy” group refers to both an —O-alkyl and an —O-cycloalkyl group, as defined herein. An “alkoxycarbonyl” refers to a —C(O)—OR. An “aminocarbonyl” refers to a —C(O)—NRR′. An “aryloxycarbonyl” refers to —C(O)—Oaryl. An “aryloxy” group refers to both an —O-aryl and an —O-heteroaryl group, as defined herein. An “arylalkyl” group refers to -alkyl-aryl, where alkyl and aryl are defined herein. An “arylsulfonyl” group refers to a —SO2-aryl. An “alkylsulfonyl” group refer to a —SO2-alkyl. A “heteroaryloxyl” group refers to a heteroaryl-O— group with heteroaryl as defined herein. A “heteroalicycloxy” group refers to a heteroalicyclic-O— group with heteroalicyclic as defined herein. A “carbonyl” group refers to a —C(═O)—R. An “aldehyde” group refers to a carbonyl group where R is hydrogen. A “thiocarbonyl” group refers to a —C(═S)—R group. A “trihalomethanecarbonyl” group refers to a Z3C—C(O)— group. A “C-carboxyl” group refers to a —C(O)O—R groups. An “O-carboxyl” group refers to a R—C(O)O— group. A “carboxylic acid” group refers to a C-carboxyl group in which R is hydrogen. A “halo” or “halogen” group refers to fluorine, chlorine, bromine or iodine. A “trihalomethyl” group refers to a —CZ3 group. A “trihalomethanesulfonyl” group refers to a Z3CS(O)2 group. A “trihalomethanesulfonamido” group refers to a Z3CS(O)2NR— group. A “sulfinyl” group refers to a —S(O)—R group. A “sulfonyl” group refers to a —S(O)2R group. An “S-sulfonamido” group refers to a —S(O)2NRR′ group. An “N-Sulfonamido” group refers to a —NR—S(O)2 R group. An “O-carbamyl” group refers to a —OC(O)NRR′ group. An “N-carbamyl” group refers to a ROC(O)NR— group. An “O-thiocarbamyl” group refers to a —OC(S)NRR′ group. An “N-thiocarbamyl” group refers to a ROC(S)NR′— group. An “amino” group refers to an —NH2 or an —NRR′ group. A “C-amido” group refers to a —C(O)NRR′ group. An “N-amido” group refers to a R′C(O)NR— group. A “nitro” group refers to a —NO2 group. A “cyano” group refers to a —CN group. A “silyl” group refers to a —Si(R)3 group. A “phosphonyl” group refers to a P(═O)(OR)2 group. An “aminoalkyl” group refers to an -alkylNRR′ group. An “alkylaminoalkyl” group refers to an -alkyl-NR-alkyl group. A “dialkylamionalkyl” group refers to an -alkyl-N-(alkyl)2 group. A “perfluoroalkyl group” refers to an alkyl group where all of the hydrogen atoms have been replaced with fluorine atoms. The definitions of R1—R10, G, R, R′ and R″ are defined in the present specification. Compounds that have the same molecular formula but differ in the nature or sequence of bonding of their atoms or arrangements of their atoms in space are termed “isomers.” Isomers that differ in the arrangement of their atoms in space are termed “stereoisomers”. Stereoisomers that are not mirror images of one another are termed “diastereomers” and those that are non-superimposable mirror images of each other are termed “enantiomers”. When a compound has an asymmetric center, for example, it is bonded to four different groups, a pair of enantiomers is possible. An enantiomer can be characterized by the absolute configuration of its asymmetric center and is described by the R- and S-sequencing rules of Cahn and Prelog, or by the manner in which the molecule rotates the plane of polarized light and designated as dextrorotatory or levorotatory (i.e., as (+) or (−)-isomers respectively). A chiral compound can exist as either individual enantiomer or as a mixture thereof. A mixture containing equal proportions of the enantiomers is called a “racemic mixture”. The chemical formulae referred to herein may exhibit the phenomena of tautomerism and structural isomerism. This invention encompasses any tautomeric or structural isomeric form and mixtures thereof which possess the ability to modulate c-Met activity and is not limited to any one tautomeric or structural isomeric form. This invention encompasses any tautomeric or structural isomeric form and mixtures thereof which possess the ability to modulate c-Met activity and is not limited to any one tautomeric or structural isomeric form. The compounds of this invention may possess one or more asymmetric centers; such compounds can therefore be produced as individual (R)— or (S)-stereoisomers or as mixtures thereof. For example, if the R2 and R3 substituents in a compound of Formula (I) are different, then that carbon is an asymmetric center. Thus, the compound of Formula (I) can exist as an (R)— or (S)-stereoisomer. Unless indicated otherwise, the description or naming of a particular compound in the specification and claims is intended to include both individual enantiomers and mixtures, racemic or otherwise, thereof. The methods for the determination of stereochemistry and the separation of stereoisomers are well-known in the art (see discussion in Chapter 4 of “Advanced Organic Chemistry”, 4th edition J. March, John Wiley and Sons, New York, 1992). Thus, this invention also encompasses any stereoisomeric form, their corresponding enantiomers (d- and 1- or (+) and (−) isomers) and diastereomers thereof, and mixtures thereof, which possess the ability to modulate c-Met activity and is not limited to any one stereoisomeric form. The compounds of the Formulae (I) and (II) may exhibit the phenomena of tautomerism and structural isomerism. For example, the compounds described herein may adopt an E or a Z configuration about a double bond or they may be a mixture of E and Z. This invention encompasses any tautomeric or structural isomeric form and mixtures thereof which possess the ability to modulate c-Met activity and is not limited to any one tautomeric or structural isomeric form. It is contemplated that compounds of the Formula (I) and (II) would be metabolized by enzymes in the body of the organism such as human being to generate a metabolite that can modulate the activity of c-Met. Such metabolites are within the scope of the present invention. The term “method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by, practitioners of the chemical, pharmaceutical, biological, biochemical and medical arts. As used herein, the term “modulation” or “modulating” refers to the alteration of the catalytic activity of c-Met. In particular, modulating refers to the activation of the catalytic activity of c-Met, preferably the activation or inhibition of the catalytic activity of c-Met, depending on the concentration of the compound or salt to which c-Met is exposed or, more preferably, the inhibition of the catalytic activity of c-Met. The term “contacting” as used herein refers to bringing a compound of this invention and c-Met together in such a manner that the compound can affect the catalytic activity of c-Met, either directly, i.e., by interacting with c-Met itself, or indirectly, i.e., by interacting with another molecule on which the catalytic activity of c-Met is dependent. Such “contacting” can be accomplished in vitro, i.e., in a test tube, a petri dish or the like. In a test tube, contacting may involve only a compound and c-Met or it may involve whole cells. Cells may also be maintained or grown in cell culture dishes and contacted with a compound in that environment. In this context, the ability of a particular compound to affect a c-Met related disorder, i.e., the IC50 of the compound, defined below, can be determined before use of the compounds in vivo with more complex living organisms is attempted. For cells outside the organism, multiple methods exist, and are well-known to those skilled in the art, to get c-Met in contact with the compounds including, but not limited to, direct cell microinjection and numerous transmembrane carrier techniques. “In vitro” refers to procedures performed in an artificial environment such as, e.g., without limitation, in a test tube or culture medium. The skilled artisan will understand that, for example, isolated c-Met may be contacted with a modulator in an in vitro environment. Alternatively, an isolated cell may be contacted with a modulator in an in vftro environment. As used herein, “in vivo” refers to procedures performed within a living organism such as, without limitation, a mouse, rat, rabbit, ungulate, bovine, equine, porcine, canine, feline, primate, or human. As used herein, “c-Met related disorder,” refers to a condition characterized by inappropriate, i.e., under-activity or, more commonly, over-activity of the c-Met catalytic activity. A “c-Met related disorder” also refers to a condition where there may be a mutation in the gene that produces c-Met, which, in turn, produces a c-Met that has an increased or decreased c-Met catalytic activity. Inappropriate catalytic activity can arise as the result of either: (1) c-Met expression in cells which normally do not express c-Met, (2) increased c-Met expression leading to unwanted cell proliferation, differentiation and/or growth, or, (3) decreased c-Met expression leading to unwanted reductions in cell proliferation, differentiation and/or growth. Over-activity of a c-Met refers to either amplification of the gene encoding a c-Met or production of a level of c-Met activity which can correlate with a cell proliferation, differentiation and/or growth disorder (that is, as the level of the c-Met increases, the severity of one or more of the symptoms of the cellular disorder increases). Under-activity is, of course, the converse, wherein the severity of one or more symptoms of a cellular disorder increase as the level of the c-Met activity decreases. As used herein, the terms “prevent”, “preventing” and “prevention” refer to a method for barring an organism from acquiring a c-Met related disorder in the first place. As used herein, the terms “treat”, “treating” and “treatment” refer to a method of alleviating or abrogating a c-Met mediated cellular disorder and/or its attendant symptoms. With regard particularly to cancer, these terms simply mean that the life expectancy of an individual affected with a cancer will be increased or that one or more of the symptoms of the disease will be reduced. The term “organism” refers to any living entity comprised of at least one cell. A living organism can be as simple as, for example, a single eukaryotic cell or as complex as a mammal. In a preferred aspect, the organism is a mammal. In a particularly preferred aspect, the mammal is a human being. The term “therapeutically effective amount” as used herein refers to that amount of the compound being administered which will relieve to some extent one or more of the symptoms of the disorder being treated. In reference to the treatment of cancer, a therapeutically effective amount refers to that amount which has the effect of (1) reducing the size of the tumor, (2) inhibiting (that is, slowing to some extent, preferably stopping) tumor metastasis, (3) inhibiting to some extent (that is, slowing to some extent, preferably stopping) tumor growth, and/or, (4) relieving to some extent (or, preferably, eliminating) one or more symptoms associated with the cancer. By “monitoring” is meant observing or detecting the effect of contacting a compound with a cell expressing a c-Met. The observed or detected effect can be a change in cell phenotype, in the catalytic activity of c-Met or a change in the interaction of c-Met with a natural binding partner. Techniques for observing or detecting such effects are well-known in the art. For example, the catalytic activity of c-Met may be observed by determining the rate or amount of phosphorylation of a target molecule. “Cell phenotype” refers to the outward appearance of a cell or tissue or the biological function of the cell or tissue. Examples, without limitation, of a cell phenotype are cell size, cell growth, cell proliferation, cell differentiation, cell survival, apoptosis, and nutrient uptake and use. Such phenotypic characteristics are measurable by techniques well-known in the art. A “natural binding partner” refers to a polypeptide that binds to a c-Met in a cell. Natural binding partners can play a role in propagating a signal in a c-Met-mediated signal transduction process. A change in the interaction of the natural binding partner with c-Met can manifest itself as an increased or decreased concentration of the c-Met/natural binding partner complex and, as a result, in an observable change in the ability of c-Met to mediate signal transduction. As used herein, “administer” or “administration” refers to the delivery of a compound or salt of the present invention or of a pharmaceutical composition containing a compound or salt of this invention to an organism for the purpose of prevention or treatment of a c-Met-related disorder. A “pharmaceutical composition” refers to a mixture of one or more of the compounds described herein, or pharmaceutically acceptable salts or prodrugs thereof, with other chemical components, such as pharmaceutically acceptable excipients. The purpose of a pharmaceutical composition is to facilitate administration of a compound to an organism. “Pharmaceutically acceptable excipient” refers to an inert substance added to a pharmaceutical composition to further facilitate administration of a compound. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils and polyethylene glycols. “Pharmaceutically acceptable salt” refers to those salts, which retain the biological effectiveness and properties of the parent compound. Such salts include: (1) acid addition salt which is obtained by reaction of the free base of the parent compound with inorganic acids such as hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, sulfuric acid, and perhcloric acid and the like, or with organic acids such as acetic acid, oxalic acid, (D) or (L) malic acid, maleic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, tartaric acid, citric acid, succinic acid or malonic acid and the like, preferably hydrochloric acid or (L)-malic acid; or (2) salts formed when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base such as ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. The compounds of the Formulae (I) and (II) may also act as prodrugs. A “prodrug” refers to an agent, which is converted into the parent drug in vivo. Prodrugs are often useful because, in some situations, they may be easier to administer than the parent drug. They may, for instance, be bioavailable by oral administration whereas the parent drug is not. The prodrug may also have improved solubility in pharmaceutical compositions over the parent drug. An example, without limitation, of a prodrug would be a compound of the present invention, which is, administered as an ester (the “prodrug”), carbamate or urea. Indications A precise understanding of the mechanism by which the compounds of the invention, in particular, the compounds generated in vivo from the compounds of the invention, inhibit c-Met is not required in order to practice the present invention. However, while not hereby being bound to any particular mechanism or theory, it is believed that the compounds interact with the amino acids in the catalytic region of c-Met. The compounds disclosed herein may thus have utility as in vitro assays for c-Met as well as exhibiting in vivo therapeutic effects through interaction with c-Met. In another aspect, this invention relates to a method for treating or preventing a c-Met related disorder by administering a therapeutically effective amount of a compound of this invention, or a salt thereof, to an organism. It is also an aspect of this invention that a pharmaceutical composition containing a compound of this invention, or a salt thereof, is administered to an organism for the purpose of preventing or treating a c-Met related disorder. This invention is therefore directed to compounds that modulate PK signal transduction by affecting the enzymatic activity of c-Met, thereby interfering with the signal transduced by c-Met. More particularly, the present invention is directed to compounds which modulate c-Met mediated signal transduction pathways as a therapeutic approach to treat the many cancers described herein. A method for identifying a chemical compound that modulates the catalytic activity of c-Met is another aspect of this invention. The method involves contacting cells expressing c-Met with a compound of this invention (or its salt) and monitoring the cells for any effect that the compound has on them. Alternatively, the method can involve contacting the c-Met protein itself (i.e., not in a cell) with a chemical compound of the preferred embodiments of the present invention and monitoring the protein for any effect that the compound has on it. The effect may be observable, either to the naked eye or through the use of instrumentation. The effect may be, for example, a change or absence in a cell phenotype. The change or absence of change in the cell phenotype monitored, for example, may be, without limitation, a change or absence of change in the catalytic activity of c-Met in the cells or a change or absence of change in the interaction of c-Met with a natural binding partner. Pharmaceutical Compositions and Use A compbund of the present invention or a physiologically acceptable salt thereof, can be administered as such to a human patient or can be administered in pharmaceutical compositions in which the foregoing materials are mixed with suitable carriers or excipient(s). Techniques for formulation and administration of drugs may be found in “Remington's Pharmacological Sciences,” Mack Publishing Co., Easton, Pa., latest edition. Routes of Administration Suitable routes of administration may include, without limitation, oral, intraoral, rectal, transmucosal or intestinal administration or intramuscular, epicutaneous, parenteral, subcutaneous, transdermal, intramedullary, intrathecal, direct intraventricular, intravenous, intravitreal, intraperitoneal, intranasal, intramuscular, intradural, intrarespiratory, nasal inhalation or intraocular injections. The preferred routes of administration are oral and parenteral. Alternatively, one may administer the compound in a local rather than systemic manner, for example, via injection of the compound directly into a solid tumor, often in a depot or sustained release formulation. Furthermore, one may administer the drug in a targeted drug delivery system, for example, in a liposome coated with tumor-specific antibody. The liposomes will be targeted to and taken up selectively by the tumor. Composition/Formulation Pharmaceutical compositions of the present invention may be manufactured by processes well known in the art, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping, lyophilizing processes or spray drying. Pharmaceutical compositions for use in the methods of the present invention may be prepared by any methods of pharmacy, but all methods include the step of bringing in association the active ingredient with the carrier which constitutes one or more necessary ingredients. In particular, pharmaceutical compositions for use in accordance with the present invention may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen. Dosage forms include tablets, troches, dispersions, suspensions, solutions, capsules, patches, syrups, elixirs, gels, powders, magmas, lozenges, ointments, creams, pastes, plasters, lotions, discs, suppositories, nasal or oral sprays, aerosols and the like. For injection, the compounds of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such buffers with or without a low concentration of surfactant or cosolvent, or physiological saline buffer. For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art. For oral administration, the compounds can be formulated by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, lozenges, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient. Pharmaceutical preparations for oral use can be made using a solid excipient, optionally grinding the resulting mixture, and processing the mixture of granules, after adding other suitable auxiliaries if desired, to obtain tablets or dragee cores. Useful excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol, cellulose preparations such as, for example, maize starch, wheat starch, rice starch and potato starch and other materials such as gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethylcellulose, sodium carboxymethylcellulose, and/or polyvinyl-pyrrolidone (PVP). If desired, disintegrating agents may be added, such as cross-linked polyvinyl pyrrolidone, agar, or alginic acid. A salt such as sodium alginate may also be used. Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses. Pharmaceutical compositions which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with a filler such as lactose, a binder such as starch, and/or a lubricant such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, liquid polyethylene glycols, cremophor, capmul, medium or long chain mono- di- or triglycerides. Stabilizers may be added in these formulations, also. For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray using a pressurized pack or a nebulizer and a suitable propellant, e.g., without limitation, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetra-fluoroethane or carbon dioxide. In the case of a pressurized aerosol, the dosage unit may be controlled by providing a valve to deliver a metered amount. Capsules and cartridges of, for example, gelatin for use in an inhaler or insulator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch. The compounds may also be formulated for parenteral administration, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulating materials such as suspending, stabilizing and/or dispersing agents. Pharmaceutical compositions for parenteral administration include aqueous solutions of a water soluble form, such as, without limitation, a salt, of the active compound. Additionally, suspensions of the active compounds may be prepared in a lipophilic vehicle. Suitable lipophilic vehicles include fatty oils such as sesame oil, synthetic fatty acid esters such as ethyl oleate and triglycerides, or materials such as liposomes. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers and/or agents that increase the solubility of the compounds to allow for the preparation of highly concentrated solutions. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use. The compounds may also be formulated in rectal compositions such as suppositories or retention enemas, using, e.g., conventional suppository bases such as cocoa butter or other glycerides. In addition to the formulations described previously, the compounds may also be formulated as depot preparations. Such long acting formulations may be administered by implantation (for example, subcutaneously or intramuscularly) or by intramuscular injection. A compound of this invention may be formulated for this route of administration with suitable polymeric or hydrophobic materials (for instance, in an emulsion with a pharmacologically acceptable oil), with ion exchange resins, or as a sparingly soluble derivative such as, without limitation, a sparingly soluble salt. A non-limiting example of a pharmaceutical carrier for the hydrophobic compounds of the invention is a cosolvent system comprising benzyl alcohol, a nonpolar surfactant, a water-miscible organic polymer and an aqueous phase such as the VPD co-solvent system. VPD is a solution of 3% w/v benzyl alcohol, 8% w/v of the nonpolar surfactant Polysorbate 80, and 65% w/v polyethylene glycol 300, made up to volume in absolute ethanol. The VPD co-solvent system (VPD:D5W) consists of VPD diluted 1:1 with a 5% dextrose in water solution. This co-solvent system dissolves hydrophobic compounds well, and itself produces low toxicity upon systemic administration. Naturally, the proportions of such a co-solvent system may be varied considerably without destroying its solubility and toxicity characteristics. Furthermore, the identity of the co-solvent components may be varied: for example, other low-toxicity nonpolar surfactants may be used instead of Polysorbate 80, the fraction size of polyethylene glycol may be varied, other biocompatible polymers may replace polyethylene glycol, e.g., polyvinyl pyrrolidone, and other sugars or polysaccharides may substitute for dextrose. Alternatively, other delivery systems for hydrophobic pharmaceutical compounds may be employed. Liposomes and emulsions are well known examples of delivery vehicles or carriers for hydrophobic drugs. In addition, certain organic solvents such as dimethylsulfoxide also may be employed, although often at the cost of greater toxicity. Additionally, the compounds may be delivered using a sustained-release system, such as semipermeable matrices of solid hydrophobic polymers containing the therapeutic agent. Various sustained-release materials have been established and are well known by those skilled in the art. Sustained-release capsules may, depending on their chemical nature, release the compounds for a few weeks up to over 100 days. Depending on the chemical nature and the biological stability of the therapeutic reagent, additional strategies for protein stabilization may be employed. The pharmaceutical compositions herein also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include, but are not limited to, calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols. Many of the PK modulating compounds of the invention may be provided as physiologically acceptable salts wherein the claimed compound may form the negatively or the positively charged species. Examples of salts in which the compound forms the positively charged moiety include, without limitation, quaternary ammonium (defined elsewhere herein), salts such as the hydrochloride, sulfate, carbonate, lactate, tartrate, maleate, succinate, malate, acetate and methylsulfonate (CH3SO3), wherein the nitrogen atom of the quaternary ammonium group is a nitrogen of the selected compound of this invention which has reacted with the appropriate acid. Salts in which a compound of this invention forms the negatively charged species include, without limitation, the sodium, potassium, calcium and magnesium salts formed by the reaction of a carboxylic acid group in the compound with an appropriate base (e.g. sodium hydroxide (NaOH), potassium hydroxide (KOH), Calcium hydroxide (Ca(OH)2), etc.). Dosage Pharmaceutical compositions suitable for use in the present invention include compositions wherein the active ingredients are contained in an amount sufficient to achieve the intended purpose, i.e., the modulation of PK activity or the treatment or prevention of a PK-related disorder. More specifically, a therapeutically effective amount means an amount of compound effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated. Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein. For any compound used in the methods of the invention, the therapeutically effective amount or dose can be estimated initially from cell culture assays. Then, the dosage can be formulated for use in animal models so as to achieve a circulating concentration range that includes the IC50 as determined in cell culture (i.e., the concentration of the test compound which achieves a half-maximal inhibition of c-Met activity). Such information can then be used to more accurately determine useful doses in humans. Toxicity and therapeutic efficacy of the compounds described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the IC50 and the LD50 (both of which are discussed elsewhere herein) for a subject compound. The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage may vary depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient's condition. (See e.g., Fingl, et al., 1975, in “The Pharmacological Basis of Therapeutics”, Ch. 1 p.1). Dosage amount and interval may be adjusted individually to provide plasma levels of the active species which are sufficient to maintain the kinase modulating effects. These plasma levels are referred to as minimal effective concentrations (MECs). The MEC will vary for each compound but can be estimated from in vftro data, e.g., the concentration necessary to achieve 50-90% inhibition of a kinase may be ascertained using the assays described herein. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. HPLC assays or bioassays can be used to determine plasma concentrations. Dosage intervals can also be determined using MEC value. Compounds should be administered using a regimen that maintains plasma levels above the MEC for 10-90% of the time, preferably between 30-90% and most preferably between 50-90%. At present, the therapeutically effective amounts of compounds of the Formulae (I) and (II) may range from approximately 10 mg/m2 to 1000 mg/m2 perday. Even more preferably 25 mg/m2 to 500 mglm2. In cases of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration and other procedures known in the art may be employed to determine the correct dosage amount and interval. The amount of a composition administered will, of course, be dependent on the subject being treated, the severity of the affliction, the manner of administration, the judgment of the prescribing physician, etc. Packaging The compositions may, if desired, be presented in a pack or dispenser device, such as an FDA approved kit, which may contain one or more unit dosage forms containing the active ingredient. The pack may for example comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the compositions or of human or veterinary administration. Such notice, for example, may be of the labeling approved by the U.S. Food and Drug Administration for prescription drugs or of an approved product insert. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition. Suitable conditions indicated on the label may include treatment of a tumor, inhibition of angiogenesis, treatment of fibrosis, diabetes, and the like. EXAMPLES Experimental Part: Example 1 (4-Hydroxy-phenyl)-acetic acid hydrazide Neat anhydrous hydrazine 21.0 g (654 mmol) was added to a solution of p-hydroxyphenylacetic acid methyl ester 27.18 g (163.5 mmol) in MeOH (100 mL) and the mixture was heated to 50-55° C. and stirred at this temperature for 90 min (water bath). Cooled, stirred for extra 1 hour, the precipitate collected by filtration, compressed on the frit, washed with MeOH (3×10 mL) and dried on high vacuum. A second fraction was obtained by cooling the supernatants to −15° C. overnight and filtering the formed precipitate. Combined yield: 25.13 g of a white crystalline solid (92.5%) 1H-NMR(DMSO-d6, 400 MHz): δ 9.182 (brs, 1H), 9.108 (brs, 1H), 7.035 (app d, J=8.6 Hz, 2H), 6.666 (app d, J=8.6 Hz, 2H), 4.176 (br d, J=3.1 Hz, 2H), 3.207 (s, 2H); 13C-NMR (DMSO-d6, 100 MHz): 170.66, 156.45, 130.47 (2C), 127.00, 115.63 (2C), 40.48. Example 2 4-(5-Amino-[1,3,4]oxadiazol-2-ylmethyl)-phenol Solid BrCN 6.059 g (57.2 mmol) was added in one portion into ice-cooled slurry of (4-hydroxy -phenyl)-acetic acid hydrazide 8.642 g (52.0 mmol) and KHCO3 6.510 g (65 mmol) in MeOH (100 mL). The mixture was stirred at 0-5° C. for 1 hour, the ice bath allowed to melt and stirred at room temperature overnight (18 hr). The reaction mixture was diluted with water (100 mL), stirred for 1 hour, the precipitate was collected by filtration, washed with water and dried on high vacuum. A second fraction precipitated after concentrating and cooling the supernatants. Combined yield: 9.018 g (90.5%) of a white crystalline solid. 1H-NMR(DMSO-d6, 400 MHz): δ 9.334 (s, 1H), 7.040 (app d, J=9.0 Hz, 2H), 6.839 (br s, 2H), 6.706 (app d, J=8.6 Hz, 2H), 3.879 (s, 2H). Example 3 4-(4,5-Diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol A mixture of 4-(5-amino-[1,3,4]oxadiazol-2-ylmethyl)-phenol 4.902 g (25.64 mmol), water 40 mL and anhydrous hydrazine 13 mL was refluxed on an oil bath (190° C.) for 18 hours. The mixture was cooled, allowed to crystallize at room temperature for 2 hours, then placed into a freezer (−20° C.) overnight (16 hrs). The precipitated product was collected by filtration, washed with chilled MeOH (−15° C.) and dried on high vacuum. The crude product was re-crystallized from water (80 mL, reflux to +4° C. overnight). Filtered, washed with ice-cold water and dried on high vacuum. Y=1.658 g (31.5%) of a white crystalline solid. MS+cAPCI: 206(M+1). MS−cAPCI: 204,202(M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 9.234 (br s,1H), 7.034 (app d, J=8.6 Hz, 2H), 2H), 6.664 (app d, J=8.6 Hz, 2H), 5.453 (br s, 2H), 5.338 (s, 2H), 3.772 (s, 2H). Example 4 (4-Fluoro-phenyl)-acetic acid hydrazide Neat anhydrous hydrazine 20 mL was added to a slurry of (4-fluorophenyl)acetic acid methyl ester (Acros Organics USA, Morris Plains, N.J., 25.66 g, 152.5 mmol) in MeOH (120 mL) and the mixture was heated to 60° C. with reflux condenser under nitrogen for 2 hrs. Cooled to room temperature, evaporated to dryness (room temperature to 60° C., 100 Torr to 7 Torr). The solid residue was re-crystallized from 1-propanol , 100 mL (reflux to room temperature, overnight). The crystallized product was collected by filtration, washed with 1-propanol and dried on high vacuum. [1st fraction] Evaporating the supernatants to dryness on high vacuum, the obtained solid residue was dried on high vacuum overnight. The residue was then re-crystallized from benzene. (reflux to room temperature, overnight) The precipitated product was collected by filtration, washed with a mixture benzene-hexane (1:1), then with hexane. Dried on high vacuum. [2nd fraction] Combined yield: 24.855 g of a white crystalline flakes (97%) 1H-NMR(DMSO-d6, 400 MHz): δ 9.194 (br s, 1H), 7.272 (m, 2H), 7.107(m, 2H), 4.202 (br d, J=4.3 Hz, 2H), 3.329 (s, 2H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-116.96 (m, 1F). Example 5 5-(4-Fluoro-benzyl)-[1,3,4]oxadiazol-2-ylamine Solid BrCN 13.37 g (130 mmol, 1.1 eq.) was added in one portion into ice-cooled slurry of (4-Fluoro-phenyl)-acetic acid hydrazide (19.85 g, 118 mmol) and KHCO3 14.77 g (147.5 mmol, 1.25 eq.) in MeOH (150 mL) in a 1L flask. (Followed by MeOH 10 mL to wash the funnel). The mixture was stirred on ice bath at 0-5° C. for 2 hours in a loose-capped flask, then the bath allowed to melt gradually and then the mixture was stirred at 5 to 20° C. overnight (17 hrs). The reaction mixture was diluted with water (200 mL), stirred for 1 hour in an open flask, then cooled on ice bath. The precipitate was collected by filtration, washed with water and dried on highvac. [1st fraction]The supernatants were concentrated on rotavap form warm (40° C.) water bath to remove all MeOH and some water. The obtained slurry was cooled to room temperature, the precipitate was collected by filtration, washed with water and dried on highvac. [2nd fraction]. Combined yield: 20.836 g (91.5%) of a white crystalline solid. 1H-NMR(DMSO-d6, 400 MHz): δ 7.289 (m, 2H), 7.148 (m, 2H), 6.873 (br s, 2H), 4.014 (s, 2H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-116.01 (m, 1F). Example 6 5-(4-Fluoro-benzyl)-[1,2,4]triazole-3,4-diamine A mixture of 5-(4-fluoro-benzyl)-[1,3,4]oxadiazol-2-ylamine 10.182 g (52.7 mmol), water 80 mL and anhydrous hydrazine 20 mL was refluxed under nitrogen on an oil bath (190-200° C.) for 23 hours. The mixture was cooled and allowed to crystallize at room temperature under nitrogen overnight. The precipitated product was collected by filtration, washed with ice-cold water (10 mL) and dried on high vacuum. The crude product was re-crystallized from water 60 mL (reflux under nitrogen, than to +4° C. in a refrigerator overnight). The product was filtered, washed with ice-cold water and dried on high vacuum. Y=6.210 g (56.5%) of a large white crystals. 1H-NMR(DMSO-d6, 400 MHz): δ 7.267 (app d, J=8.6Hz, J=5.5Hz, 2H), 7.097 (app t, J=9.0 Hz, 2H), 5.509 (br s, 2H), 5.339 (s, 2H), 3.884 (s, 2H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-117.14 (m, 1F). Example 7 3,3,4-Trichloro-5-methoxy-1,3-dihydro-indol-2-one According to the procedure published by R. J. Bass in Tetrahedron 27, 3263-70 (1971), the chlorination of 5-methoxyindole-2-carboxylic acid provided 3,3,4-trichloro-5-methoxy-1,3-dihydro-indol-2-one in 47% Y (after re-crystallization). 1H-NMR(CDCl3, 400 MHz): δ 11.342 (br s, 1H), 7.207 (d, J=9.0Hz, 1H), 6.903 (d, J=8.6 Hz, 1H), 3.846 (s, 3H). Example 8 4-Chloro-5-methoxy-1H-indole-2,3-dione Hydrolysis of 3,3,4-trichloro-5-methoxy-1,3-dihydro-indol-2-one in MeOH-water mixture according to the procedure published in Tetrahedron 27, 3263-70 (1971) provided 4-chloro-5-methoxy-1H-indole-2,3-dione as a deep-brown shiny crystals in 96% Y. 1H-NMR(DMSO-d6, 400 MHz): δ 10.996 (br s, 1H), 7.338 (d, J=8.6 Hz, 1H), 6.791 (d, J=8.6 Hz, 1H), 3.825 (s, 3H). Example 9 3,3,4,7-Tetrachloro-5-methoxy-1,3-dihydro-indol-2-one 11.54 g of 3,3,4-trichloro-5-methoxy-1 ,3-dihydro-indol-2-one (43.3 mmol) was suspended in glacial AcOH (200 mL). 3.343 g (21.7 mmol) of N,N-dichlorourethane was added and the mixture was stirred at 60° C. for 2 days. The reaction mixture was cooled to room temperature, the precipitate collected by filtration and dried on high vacuum. Re-crystallization from benzene (150 mL) yielded 6.135 g of product (containing 5% of the start. material as an impurity). The AcOH-supernatants from the react. mixture were diluted with water (200 mL) and the precipitated second fraction was collected by filtration, dried on high vacuum. This second fraction was combined with evap. residue of the benzene supernatants from the first fraction re-crystallization and re-crystallized twice from benzene (2×100 mL). This re-crystallized material (2.300 g) contained 8% of the starting material as an impurity. Combined yield: 8.521 g (65.5%) of a white crystalline solid. 1H-NMR(DMSO-d6, 400 MHz): δ 11.842 (br s,1H), 7.370 (s,1H), 3.879 (s, 3H). Example 10 4,7-Dichloro-5-methoxy-1H-indole-2,3-dione 3.841 g of 3,3,4,7-tetrachloro-5-methoxy-1,3-dihydro-indol-2-one (12.76 mmol) was refluxed in a mixture of MeOH (125 mL) and water (75 mL) for 32 hours. Allowed to crystallize overnight, the precipitated product collected by filtration and dried on highvac. Y=2.708 g of a deep red-brown shiny crystalline solid (86%) The product contained 3% of 4-Chloro-5-methoxyisatin, originating from the impurity in the starting material. 1H-NMR(DMSO-d6, 400 MHz): δ 11.407 (br s,1H), 7.447 (s, 1H), 3.857 (s, 3H). Example 11 4-Chloro-5-hydroxy-1H-indole-2,3-dione 4-Chloro-5-hydroxy-1H-indole-2,3-dione 2.116 g (10 mmol) was suspended in anhydrous dichloromethane (20 mL) and cooled on ice bath under nitrogen. Boron tribromide 3.00 mL (31.7 mmol) was added neat (over 10 minutes) and the obtained mixture was stirred at 0° C. to room temperature for 30 minutes and at room temperature overnight (16 hr) under nitrogen. With cooling on ice bath, the reaction mixture was quenched by slow addition of crushed ice, the mixture was then diluted with methanol (80 mL) and water (150 mL) and stirred for 15 minutes. The precipitate was collected by filtration, washed with mixture of methanol+water (1:2) and dried on high vacuum. Y=1.716 g (87%) of a brown solid. 1H-NMR(DMSO-d6, 400 MHz): δ 10.877 (br s, 1H), 10.100 (br s, 1H), 7.150 (dAB, J=8.6 Hz, 1H), 6.698 (dAB, J=8.6 Hz, 1H). Example 12 Synthesis of 4-Chloro-2,3-dioxo-2,3-dihydro-1H-indole-5-carboxylic acid (two steps) 2-Chloro-4-(2-hydroxyim ino-acetylam ino)-benzoic acid To a solution of chloral hydrate (1.0 g, 6.00 mmol; Spectrum Quality Products, Inc., New Brunswick, N.J.) and water (80 mL) was added sodium sulfate (5 g), 4-amino-2-chloro-benzoic acid (855 mg, 4.98 mmol; Acros), concentrated aq. HCl (5 mL) and hydroxylamine hydrochloride (1.15 g, 16.5 mmol; Aldrich). It was refluxed for 20 minutes. The mixture was cooled to rt, the precipitate was filtered and washed with water. The title compound (1.08 g, 90%) was obtained as a white solid. 1H NMR (400 MHz, DMSO-d6) δ 7.63 (s, 1H), 7.67 (d, J=2.0 Hz, 1H), 7.69 (d, J=2.3 Hz, 1H), 7.82 (d, J=8.6 Hz, 1H), 7.95 (d, J=2.0 Hz, 1H), 10.52 (s, 1H), 12.31 (s, 1H), 12.95 (vbr s, 1H). 4-Chloro-2,3-dioxo-2,3-dihydro-1H-indole-5-carboxylic acid (Major Isomer) 2-chloro-4-[(-2-(hydroxyimino)ethanoyl)amino]benzoic acid (300 mg, 1.24 mmol) was dissolved in concentrated sulfuric acid (5 mL). It was stirred at 80° C. for 3 h. The reaction mixture was cooled to rt, poured into ice water and it was extracted twice with ethylacetate. The title compound was obtained as an orange solid (256 mg, 92%) containing 12% of the regioisomer (6-chloro-2,3-dioxoindoline-5-carboxylic acid). 1H NMR (400 MHz, d6-DMSO) δ 6.88 (d, J=8.6 Hz, 1H), 8.02 (d, J=8.2 Hz, 1H), 11.41 (s, 1H), 13.24 (brs, 1H). Example 13 4,7-Dimethyl-5-(2-morpholin-4-yl-ethoxy)-1H-indole-2,3-dione Step 1: N-(4-Hydroxy-2,5-dimethyl-phenyl)-acetamide To a suspension of 4-amino-2,5-dimethyl-phenol (6.85 g, 50 mmol) in 30 mL of water was added acetic anhydride (5.67 mL, 60 mmol). The mixture was vigorously stirred at 70° C. for 20 min and then cooled down to room temperature. The solid was collected by filtration and washed with water to give N-(4-hydroxy-2,5-dimethyl-phenyl)-acetamide as gray solid (8.1 g, 90%). 1H-NMR (400 MHz, DMSO-d6) δ 9.00 (s, 2H), 6.89 (s, 1H), 6.55 (s, 1H), 2.03 (s, 3H), 2.02 (s, 3H), 1.96 (s, 3H). MS (m/z) 180 [M+1]. Sep 2: N-[2,5-Dimethyl-4-(2-morpholin-4-yl-ethoxy)-phenyl]-acetamide To a suspension of N-(4-hydroxy-2,5-dimethyl-phenyl)-acetamide (8.0 g, 44.6 mmol) and 4-(2-chloro-ethyl)-morpholine hydochloride (9.97 g, 53.6 mmol) in 50 mL of dioxane was added a solution of NaOH (4.29 g in 50 mL of water). The mixture was refluxed for 2 h and evaporated to dryness under reduced pressure. The residue was dissolved in CH2Cl2 and washed with 0.5 N NaOH. The organic phase was dried (Na2SO4), evaporated, and crystallized from CH2Cl2-hexane to give N-[2,5-dimethyl-4-(2-morpholin-4-yl-ethoxy)-phenyl]-acetamide as gray solid (11.6 g, 89%). 1H-NMR (400 MHz, DMSO-d6) δ 9.08 (s, 1H), 7.00(s, 1H), 6.75 (s, 1H), 4.04 (t, 2H) 3.56 (t, 4H), 2.69 (t, 2H), 2.49 (m, 4H), 2.10 (s, 3H), 2.06 (s, 3H), 1.98 (s, 3H). MS (m/z) 293 [M+1]. Step 3: 2,5-Dimethyl-4-(2-morpholin-4-yl-ethoxy)-phenylamine hydrogen chloride The mixture of N-[2,5-dimethyl-4-(2-morpholin-4-yl-ethoxy)-phenyl]-acetamide (11.4 g, 39 mmol) in 3N aq.HCl (100 mL) was refluxed for 2 h and then concentrated under reduced pressure. The residue was lyophilized to give 2,5-dimethyl-4-(2-morpholin-4-yl-ethoxy)aniline dihydrochloride as gray solid quantitatively. 1H-NMR (400 MHz, DMSO-d6) δ 11.75 (brs, 1H), 10.17 (brs, 3H), 7.22 (s, 1H), 6.94 (s, 1H), 4.45 (t, 2H), 3.77-4.04 (m, 6H), 3.54 (t, 2H), 3.45 (m, 2H), 3.21 (m, 2H), 2.33 (s, 3H), 2.15 (s, 3H). MS (m/z) 251 [M+1]. Step 4: N-[2,5-D imethyl-4-(2-morpholin-4-yl-ethoxy)-phenyl]-2-hydroxyimino-acetamide To a solution of chloral hydrate (910 mg, 5.5 mmol) in 12 mL of water were added, in order: 13 g of anhydrous Na2SO4; a solution of 2,5-dimethyl-4-(2-morpholin-4-yl-ethoxy)-pheylamine hydrogen chloride (1.61 g, 5 mmol) in water (3 mL); and finally, a solution of hydroxylamine hydrochloride (1.12 g, 16 mmol) in 5 mL of water. The mixture was heated in an oil bath (130° C.) with stirring for 15 min, then cooled down to room temperature, diluted with water, neutralized to pH 7 with concentrate aq. NaHCO3, and extracted with EtOAc. The combined organic layer was was washed with water, dried (Na2SO4) and concentrated under reduced pressure to give N-[2,5-dimethyl-4-(2-morpholin-4-yl-ethoxy)-phenyl]-2-hydroxyimino-acetamide as yellow solid (1.45 g, 91%). 1H-NMR (400 MHz, DMSO-d6) δ 12.04 (s, 1H), 9.34 (s, 1H), 7.60 (s, 1H), 7.09 (s, 1H), 6.80 (s, 1H), 4.06 (t, 2H), 3.57 (t, 2H), 2.70 (t, 2H), 2.49 (m, 4H), 2.13 (s, 3H), 2.08 (s, 3H). MS (m/z) 322 [M+1]. Step 5: 4,7-Dimethyl-5-(2-morpholin-4-yl-ethoxy)-1 H-indole-2,3-dione To concentrated H2SO4 (3.5 mL) at 60° C. was added N-[2,5-dimethyl-4-(2-morpholin-4-yl-ethoxy)-phenyl]-2-hydroxyimino-acetamide (1.4 g, 4.36 mmol) in portions with stirring. After the addition was finished, the mixture was heated to 75° C. and kept at this temperature for 15 min. A dark-purple solution was formed and poured upon cracked ice. Then solid NaHCO3 is added and pH was adjusted to 8.0. The mixture was extracted with CH2Cl2, dried (Na2SO4), and crystallized from CH2Cl2-hexane to give 4,7-Dimethyl-5-(2-morpholin-4-yl-ethoxy)-1H-indole-2,3-dione as brown solid 1.15 g, 87%). 1H-NMR (400 MHz, DMSO-d6) δ 10.84 (s, 1H), 7.03 (s, 1H), 4.03 (t, 2H), 3.57 (t, 2H), 2.67 (t, 2H), 2.46 (t, 4H), 2.29 (s, 3H), 2.13 (s, 3H). MS (m/z) 305 [M+1]. Example 14 5-(2-Diethylamino-ethyl)-4,7-dimethyl-1H-indole-2,3-dione hydrochloride Synthetic Scheme: Step 1. N-[4-(2-Bromo-acetyl)-2,5-dimethyl-phenyl]-acetamide Neat bromoacetyl bromide 40.11 g(198.7 mmol) was added into a stirred slurry of aluminum chloride 34.2 g (256.5 mmol) in anhydrous dichloroethane (40 mL) at 0° C. over 1 min period and the mixture was stirred on ice bath for 1 hour under dry nitrogen. A solution prepared by dissolving 2,5-dimethylacetanilide 16.624 g (101.85 mmol) in hot anhydrous dichloroethane (80 mL) was added while hot (quickly, in order to prevent the starting acetanilide solution from congealing) into the ice-cooled aluminum chloride mixture and the obtained homogenous mixture was stirred at 0-5° C. for 90 minutes (the ice bath was allowed to melt) and at 5-10° C. for 30 minutes and then at 10° C. to room temperature for additional 4½ hours under nitrogen. The reaction mixture was poured onto crushed ice in a large beaker, stirred for 10 minutes. The aqueous phase was poured off, the remaining white sticky semi-solid material was mixed with hexane (0.7 L) and the mixture was stirred for 15 minutes. The precipitate was collected by filtration, washed with plenty of hexane and water (repeatedly), compressed on the frit, washed again with water, then dried by air suction, then on high vacuum (2 days). Y=29.08 g (100% ) of a white solid. The material contained 3% of the analogous chloroacetyl product as an impurity. 1H-NMR (DMSO-d6, 400 MHz): δ 9.355 (br s, 1H), 7.771 (s, 1 H), 7.542 (s, 1H), 4.823 (s, 2H), 2.363 (s, 3H), 2.234 (s, 3H), 2.096 (s, 3H). Step 2: N-[4-(2-Bromo-ethyl)-2,5-dimethyl-phenyl]-acetamide Triethylsilane 60 mL (375 mmol) was added to trifluoroacetic acid 360 mL and stirred until a homogenous mixture was obtained (15 minutes). This mixture was then added to solid N-[4-(2-bromo-acetyl)-2,5-dimethyl-phenyl]-acetamide 28.88 g (101.64 mmol) in an ice-cooled flask. The flask was capped with a Dryerite-filled tube (as a gas outlet) and the mixture was stirred on ice bath for 1 hour, then at room temperature for 1 day. The reaction mixture was evaporated and the obtained thick residue was suspended in hexane (0.3L). Water (100 mL) was added and the mixture was stirred and occasionally shaken for about 1 hour. The formed precipitate was collected by filtration, washed repeatedly with plenty of hexane and water, compressed on the frit, dried by air suction, then on high vacuum. Y=27.30 g of a white solid (99.5%). The material contained 3% of the analogous chloroethyl product, which originated from impurity in the starting material. 1H-NMR (DMSO-d6, 400 MHz): δ 9.175 (br s, 1H), 7.163 (s, 1H), 7.025 (s, 1H), 3.641 (t, J=7.4 Hz, 2H), 3.051 (t, J=7.8 Hz, 2H), 2.212 (s, 3H), 2.121 (s, 3H), 2.023 (s, 3H). Step 3: N-[4-(2-Diethylamino-ethyl)-2,5-dimethyl-phenyl]-acetamide A mixture of N-[4-(2-bromo-ethyl)-2,5-dimethyl-phenyl]-acetamide 9.00 g (33.3 mmol), diethylamine 150 mL and acetonitrile (110 mL) was stirred at reflux (oil bath) for 14 hours. The mixture was evaporated, the obtained solid was suspended in water (200 mL), made strongly alkaline with 15% aq. NaOH (20 mL) and the mixture was stirred and occasionally shaken for 6 hours. The solids were collected by filtration, compressed on the frit, washed with water and dried on highvac. (This was the fraction 1). The filtrates were diluted with saturated aqueous sodium bicarbonate 100 mL and extracted with ethyl acetate (2×250 mL). The combined org. extracts were dried (magnesium sulfate) and evaporated. The solid residue was dried on highvac. (Fraction 2). The combined fractions (1+2) were dissolved in hot benzene (100 mL), the obtained cloudy solution was diluted with ether (200 mL), filtered, diluted with additional ether (200 mL). With stirring, 4M HCl in dioxane (20 mL) was added dropwise and the obtained slurry was stirred for 2 hours. The precipitated solids were collected by quick filtration, rinsed with ether and dried on high vacuum. This crude acetanilide intermediate HCl salt (9.55 g, 96% Y) was dissolved in water (100 mL, with sonication) and the cloudy solution was filtered from a small amount of insoluble impurities (washed with additional water, 3×10 mL). The filtrates were concentrated down to approximatel 100 mL overall volume, concentrated hydrochloric acid (100 mL) was added and the mixture was refluxed on an oil bath (170-180° C.) for 2 hours. The reaction mixture was evaporated to dry and the residue was dried on high vacuum. Y=8.101 g of a light-tan very hygroscopic solid (83% overall). 1H-NMR (DMSO-d6, 400 MHz): δ 10.982 (br s, 1H), 10.327 (br s, 3H), 7.244 (s, 1H), 7.175 (s, 1H), 3.160 (m, 6H), 3.028 (m, 2H), 2.311 (s, 3H), 2.292 (s, 3H), 1.250 (t, J=7.4 Hz, 6H). Step 4: 5-(2-Diethylamino-ethyl)-4,7-dimethyl-1H-indole-2,3-dione hydrochloride 8.100 g of N-[4-(2-diethylamino-ethyl)-2,5-dimethyl-phenyl]-acetamide.2HCl (27.62 mmol), chloral hydrate 5.000 g (30.2 mmol) and sodium sulfate (anhydrous) 36 g was stirred in water 100 mL for 20 minutes. Hydroxylamine hydrochloride 6.25 g (90 mmol) in water 30 mL was added, the mixture was stirred at room temperature for 10 min, then placed on oil bath and stirred at 80-85° C. for 90 minutes. The react. mixture was diluted with saturated NaCl (250 mL) and stirred at room temperature overnight. The precipitate was collected by filtration, washed with saturated NaCl, dried by air suction, then on highvac overnight. The obtained dry intermediate (containing some salt) was added in small portions into 50 mL of an ice-cooled 5:1 (v/v) mixture of concentrated sulfuric acid (96%) and water, in a 0.5 L wide-mouth flask, over 10 minute period. (There was effervescence due to the HCl gas evolution). The cooling bath was removed and the mixture was stirred at room temperature until all chunks of the intermediate dissolved (2 hours). The formed dark thick mixture was then stirred on oil bath at 75-80° C. for 1 hour. The reaction mixture was cooled on ice bath and ice (1 handful) was added, followed after 10 minutes with saturated NaCl (450 mL). The deep purple mixture was stirred on ice bath for 3 hours. The precipitated solids were collected by filtration, washed with ice-cold saturated NaCl and dried by air suction and on highvac. The salt-containing product was extracted in a Soxhlet apparatus with mixture chloroform-anhydrous ethanol 1:1 (v/v), 200 mL, until all colorful material was extracted (oil bath, ½ day reflux). The extract was allowed to crystallize at room temperature overnight, the precipitated product first fraction (4.412 g) was collected by filtration, washed with anhydrous ethanol and dried on highvac. A second fraction (1.262 g) was collected by concentrating the supernatants to a small volume (approximatel 40 mL), re-heating to reflux, followed by crystallization overnight. Combined yield: 5.674 g of an orange cryst. solid (66% overall). 1H-NMR (DMSO-d6, 400 MHz): δ 11.033 (s,1H), 10.760 (br s, 1H), 7.289 (s,1H), 3.162 (m, 4H), 3.050 (m, 2H), 2.983 (m, 2H), 2.461 (s, 3H), 2.136 (s, 3H), 1.248 (t, J=7.4 Hz, 6H). Example 15 4,7-Dimethyl-5-(2-pyrrolidin-1-yl-ethyl)-1H-indole-2,3-dione hydrochloride Step 1: 2,5-Dimethyl-4-(2-pyrrolidin-1-yl-ethyl)-phenylamine A mixture of N-[4-(2-bromo-ethyl)-2,5-dimethyl-phenyl]-acetamide 9.00 g (33.3 mmol) and neat pyrrolidine 150 mL was stirred at 70° C. for 4½ hours. Evaporating the react mixture and drying the residue on highvac a solid was obtained. This material was dissolved in water (100 mL), treated with 15% aq. NaOH (20 mL) and cooled on ice bath for 1 hour. The precipitate was collected by filtration, washed with water and dried on highvac. (Fraction 1) The filtrates were diluted with saturated aqueous sodium bicarbonate 100 mL and extracted with ethyl acetate (2×250 mL). The combined org. extracts were dried (magnesium sulfate) and evaporated. The solid residue was dried on highvac. (Fraction 2). The combined fractions were dissolved in hot benzene (100 mL), THF (100 mL) was added, diluted with ether (0.5 L). With stirring, 4M HCl in dioxane (20 mL) was added dropwise and the obtained slurry was stirred for 2 hours. The precipitated solids were collected by quick filtration, rinsed with ether and dried on highvac. This crude acetanilide intermediate-HCl salt (9.85 g, 99.5% Y) was dissolved in water (70 mL, with 30 min stirring) and the obtained cloudy solution was filtered from a small amount of insoluble impurities (washed with additional water, 3×10 mL). The filtrates were combined with concentrated hydrochloric acid (100 mL) and the mixture was refluxed on oil bath (170-180° C.) for 2 hours. The reaction mixture was evaporated to driynes and the residue was dried on high vacuum. Y=8.53 g of a light-tan hygroscopic solid (88% overall). 1H-NMR (DMSO-d6, 400 MHz): 11.315 (br s,1H), 10.281 (br s, 3H), 7.233 (s,1 H), 7.150 (s, 1H), 3.529 (m, 2H), 3.204 (m, 2H), 3.014 (m, 4H), 2.301 (s, 3H), 2.287 (s, 3H), 1.999 (m, 2H), 1.883 (m, 2H). Step 2: 4,7-Dimethyl-5-(2-pyrrolidin-1-yl-ethyl)-1H-indole-2,3-dione hydrochloride 8.35 g of 2,5-dimethyl-4-(2-pyrrolidin-1-yl-ethyl)-phenylamine. 2HCl (29.29 mmol) 5.293 g of chloral hydrate (32 mmol) and 38 g of sodium sulfate (anhydrous) was suspended in water 100 mL, hydroxylamine hydrochloride 6.60 g (95 mmol) and water 40 mL was added and the mixture was refluxed under nitrogen on oil bath (140-150° C.) for 1 hour. The reaction mixture was stirred at room temperature overnight, the-precipitated solids were collected by filtration (without washing) and dried by air suction, then on highvac. The obtained intermediate was added in small portions into 50 mL of an ice-cooled 5:1(v/v) mixture of concentrated sulfuric acid (96%) and water, in a 0.5L wide-mouth flask, over 10 minute period. The cooling bath was removed and the mixture was stirred at room temperature until all chunks of the intermediate dissolved (1 hour). The formed dark thick mixture was then stirred on an oil bath at 75-80° C. for 1 hour. The reaction mixture was cooled on ice bath and ice (1 handful) was added, followed after 10 minutes with saturated NaCl (250 mL). The rest of the procedure was practically identical to the above preparation of 5-(2-Diethylamino-ethyl)-4,7-dimethyl-1H-indole-2,3-dione hydrochloride. Combined product yield was 4.536 g (50% overall) of a brick-red crystalline solid. 1H-NMR (DMSO-d6, 400 MHz): δ 11.100 (br s, 1H), 11.028 (s, 1H), 7.266 (s, 1H), 3.530 (m, 2H), 3.181 (m, 2H), 3.014 (m, 2H), 2.975 (m, 2H), 2.455 (s, 3H), 2.132 (s, 3H), 2.000 (br m, 2H), 1.882 (m, 2H). Example 16 4,7-Dimethyl-5-(2-morpholin-4-yl-ethyl)-1H-indole-2,3-dione hydrochloride Step 1: 2,5-Dimethyl-4-(2-morpholin-4-yl-ethyl)-phenylamine hydrochloride A mixture of N-[4-(2-bromo-ethyl)-2,5-dimethyl-phenyl]-acetamide 9.00 g (33.3 mmol) and neat morpholine 150 mL was stirred at 70° C. for 6 hours. Evaporating the reaction mixture and drying the residue on highvac, a solid was obtained. The material was dissolved in boiling water (50 mL), treated with 15% aq. NaOH (20 mL) and cooled on ice bath for 3 hours. The precipitate (a small amount of material, mostly the impurities) was collected by filtration, washed with water and discarded. The filtrates were diluted with saturated aqueous sodium bicarbonate 100 mL and extracted repeatedly with large volume of ethyl acetate (8×250 mL). The combined org. extracts were dried (magnesium sulfate) and evaporated. The solid residue was dried on highvac. The material was dissolved in refluxing benzene (100 mL), diluted with hot hexane (200 mL) and stirred at room temperature overnight. The formed precipitate was collected by filtration, washed with hexane and dried on high vacuum. (Fraction 1, 7.888 g). The benzene/hexane supernatants were evaporated to dryines, the residue dissolved in hot benzene (50 mL), the solution diluted with hot hexane (150 mL) and allowed to crystallize overnight. The precipitated material was collected by filtration, washed with hexane and dried on high vacuum. (Fraction 2, 0.570 g) The combined fractions (1+2) of this acetanilide intermediate (8.458 g, 92%) were dissolved in water 80 mL, concentrated hydrochloric acid 80 mL was added. The mixture was refluxed on oil bath (170-180° C.) for 3 hours. The reaction mixture was evaporated to dryines and the residue was dried on high vacuum. Y=9.343 g of a pale yellow hygroscopic solid (92% overall. 1H-NMR (DMSO-d6, 400 MHz): δ 11.593 (br s, 1H), 10.072 (br s, 3H), 7.194 (s, 1H), 7.115 (s, 1H), 3.964 (br m, 2H), 3.840 (br m, 2H), 3.490 (br d, 2H), 3.162 (br m, 2H), 3.063 (m, 4H), 2.290 (s, 6H). Step 2: 4,7-Dimethyl-5-(2-morpholin-4-yl-ethyl)-1H-indole-2,3-dione hydrochloride 8.100 g of 2,5-dimethyl-4-(2-morpholin-4-yl-ethyl)-phenylamine.2HCl (27.62 mmol), chloral hydrate 5.000 g (30.2 mmol) and sodium sulfate (anhydrous) 36 g was stirred in water 100 mL for 20 minutes. Hydroxylamine hydrochloride 6.25 g (90 mmol) in water 30 mL was added, the mixture was stirred at room temperature for 10 min, then placed on oil bath and stirred at 80-85° C. for 90 minutes. The react. mixture was diluted with saturated NaCl (250 mL) and stirred at room temperature overnight. The precipitate was collected by filtration, washed with saturated NaCl, dried by air suction, then on high vacuum overnight. The obtained dry intermediate (containing some salt) was added in small portions into 50 mL of an ice-cooled 5:1 (v/v) mixture of concentrated sulfuric acid (96%) and water, in a 0.5 L wide-mouth flask, over 10 minute period. (There was effervescence due to the HCl gas evolution). The cooling bath was removed and the mixture was stirred at room temperature until all chunks of the intermediate dissolved (2 hours). The formed dark thick mixture was then stirred on oil bath at 75-80° C. for 1 hour. The reaction mixture was cooled on ice bath and ice (1 handful) was added, followed after 10 minutes with saturated NaCl (450 mL). The deep purple mixture was stirred on ice bath for 3 hours. The precipitated solids were collected by filtration, washed with ice-cold saturated NaCl and dried by air suction and on highvac. The salt-containing product was extracted in a Soxhlet apparatus with mixture chloroform-anhydrous ethanol 1:1 (v/v), 200 mL, until all colorful material was extracted (oil bath, ½ day reflux). The extract was allowed to crystallize at room temperature overnight, the precipitated product first fraction (4.412 g) was collected by filtration, washed with anhydrous ethanol and dried on highvac. A second fraction (1.262 g) was collected by concentrating the supernatants to a small volume (approximatel 40 mL), re-heating to reflux, followed by crystallization overnight. Combined yield: 5.674 g of an orange cryst. solid (66% overall). 1H-NMR (DMSO-d6, 400 MHz): δ 11.033 (s, 1H), 10.760 (br s, 1H), 7.289 (s, 1H), 3.162 (m, 4H), 3.050 (m, 2H), 2.983 (m, 2H), 2.461 (s, 3H), 2.136 (s, 3H), 1.248 (t, J=7.4 Hz, 6H). Example 17 4-(9H-1,2,3a,4,9,10-Hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol In a pressure tube, 74 mg of 1H-indole-2,3-dione (0.500 mmol) and 103 mg of 4-(4,5-diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol (0.500 mmol) in a mixture of trifluoroethanol (8 mL) and water (4 mL) was stirred at 125° C. overnight (19 hr). The mixture was cooled to room temperature, allowed to crystallize for 3 hours. The precipitated product was collected by filtration, washed with MeOH+water 1:1, then with MeOH and dried on high vacuum. Y=126 mg of a yellow solid (79.5%). [An analogous parallel experiment performed in a mixture EtOH (4 mL) plus water (4 mL) plus AcOH (0.10 mL) yielded 126 mg(79.5%) of the identical product]. MS+cAPCI: 317(M+1). MS−cAPCI: 315(M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.187 (br s, 1H), 9.261 (s, 1H), 8.151 (app d, J=7.4 Hz, 1H), 7.701 (app t, J=7.2 Hz, 1H), 7.417 (app d, J=8.2 HZ, 1H), 7.324 (app t, J=7.8 Hz, 1H), 7.180 (app d, J=8.6 Hz, 2H), 6.685 (app d, J=8.6 Hz, 2H), 4.413 (s, 2H). Example 18 4-(5,8-Dichloro-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol (General Cyclization Procedure) In a pressure tube, 0.60 mmol of 4,7-dichloro-1H-indole-2,3-dione (130 mg) and 0.65 mmol of 4-(4,5-diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol (133.5 mg) in a mixture of trifluoroethanol (8 mL) and water (4 mL) was stirred at 125° C. overnight (16 hr). The mixture was cooled to room temperature, allowed to crystallize for 2 hours. The precipitated product was collected by filtration, washed with MeOH+water 1:1, then with chilled MeOH. Dried on high vacuum. Y=209 mg of a deep yellow solid (90.5%). MS+cAPCI: 387, 385 (M+1). MS−cAPCI: 385, 383 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.864 (br s, 1H), 9.259 (s, 1H), 7.797 (d, J=8.6 Hz, 1H), 7.406 (d, J=8.6 Hz, 1H), 7.250 (app d, J=8.6 Hz, 2H), 6.674 (app d, J=8.6 Hz, 2H), 4.408 (s, 2H). Example 19 4-(5-Chloro-6-methoxy-9H-1 ,2,3a,4,9, 10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 127 mg of 4-chloro-5-methoxy-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=190 mg of a light-red solid (83%). MS+cAPCI: 383, 381 (M+1). MS−cAPCI: 381, 379 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.178 (br s, 1H), 9.251 (s, 1H), 7.528 (d, J=9.0 Hz, 1H), 7.331 (d, J=8.6 Hz, 1H), 7.248 (app d, J=8.6 Hz, 2H), 6.668 (app d, J=8.6 Hz, 2H), 4.387 (s, 2H), 3.932 (s, 3H). Example 20 4-(5,8-Dichloro-6-methoxy-9H-1 ,2,3a,4,9, 10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 148 mg of 4,7-dichloro-5-methoxy-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=239 mg of a light-red solid (96%). MS+cAPCI: 417, 415 (M+1). MS−cAPCI: 415, 413 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.588 (br s, 1H), 9.253 (s, 1H), 7.659 (s, 1H), 7.245 (app d, J=8.6 Hz, 2H), 4.393 (s, 3H), 3.953 (s, 3H) Example 21 4-(5-Chloro-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 109 mg of 4-chloro-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=175 mg of a yellow solid (83%). MS+cAPCI: 353, 351 (M+1). MS−cAPCI: 353, 349 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.426 (br s, 1H), 9.252 (s, 1H), 7.682 (app t, J=8.2 Hz, 1H), 7.390 (app d, J=3.1 Hz, 1H), 7.370 (app d, J=2.8 Hz, 1H), 7.250 (app d, J=8.6 Hz, 2H), 6.672 (app d, J=8.6 Hz, 2H), 4.396 (s, 2H). Example 22 4-(8-Chloro-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 109 mg of 7-chloro-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=195 mg of a yellow solid (92.5%). MS+cAPCI: 353, 351 (M+1). MS−cAPCI: 353, 349, 348 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.628 (br s,1H), 9.265 (s, 1H), 8.140 (dd, J=7.8 Hz, J=1.2 Hz, 1H), 7.799 (dd, J=7.8 Hz, J=1.2 Hz,1H), 7.335 (app t, J=7.8 Hz, 1H), 7.184 (app d, J=8.6 Hz, 2H), 6.686 (app d, J=8.6 Hz, 2H), 4.424 (s, 2H). Example 23 4-(5,6,8-Trichloro-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 150.5 mg of 4,5,7-trichloro-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=237 mg of a yellow solid (94%). MS+cAPCI: 353, 351 (M+1). MS−cAPCI: 353, 349, 348 (M−1). 1H-NMR(DMSO-d6, 400 MHz): 13.016 (br s, 1H), 9.259 (s, 1H), 8.194 (s, 1H), 7.252 (app d, J=8.6 Hz, 2H), 6.677 (app d, J=8.6 Hz, 2H), 4.419 (s, 2H). Example 24 4-(5,8-Dimethyl-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol, dihydrate According to the general cyclization procedure (for Example 18), 105.5 mg of 4,7-dimethyl-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=67.5 mg of a light brown solid (29.5%). MS+cAPCI: 345 (M+1). MS−cAPCI: 343 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.107 (br s, 1H), 9.257 (s, 1H), 7.367 (br d, J=7.8 Hz, 1H), 7.215 (app d, J=8.6 Hz, 2H), 7.024 (br d, J=7.4 Hz, 1H), 6.678 (app d, J=8.6 Hz, 2H), 4.393 (s, 2H), 3.318 (s, 4H), 2.738 (s, 3H), 2.408 (s, 3H). Example 25 4-(6,8-Dimethyl-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 105.5 mg of 5,7-dimethyl-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=159 mg of a yellow solid (77%). MS+cAPCI: 345 (M+1). MS−cAPCI: 343, 342 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.049 (br s, 1H), 9.264 (s, 1H), 7.742 (br s, 1H), 7.315 (br s, 1H), 7.179 (app d, J=8.6 Hz, 2H), 6.690 (app d, J=8.6 Hz, 2H), 4.396 (s, 2H), 2.416 (s, 3H), 2.385 (s, 3H). Example 26 4-(6-Chloro-8-methyl-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 18), 117.5 mg of 5-chloro-7-methyl-1H-indole-2,3-dione (0.6 mmol) was used for the preparation. Y=201 mg of a yellow solid (92%). MS+cAPCI: 367, 365 (M+1). MS−cAPCI: 365, 363 (M−1). 1H-NMR(dDMSO, 400 MHz): δ 12.332 (br s, 1H), 9.263 (s, 1H), 8.025 (br d, J=2.0 Hz, 1H), 7.598 (br m, 1H), 7.202 (app d, J-8.6 Hz, 2H), 6.690 (app d, J=8.6 Hz, 2H), 4.404 (s, 2H), 2.466 (s, 3H). Example 27 5,8-Dichloro-3-(4-fluoro-benzyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorine (General Cyclization Procedure) In a pressure tube, 0.60 mmol of 4,7-dichloro-1H-indole-2,3-dione (130 mg) and 0.70 mmol of 5-(4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) in a mixture of trifluoroethanol (8 mL) and water (4 mL) was stirred at 125° C. overnight (14 hr). The mixture was cooled to room temperature, allowed to crystallize for 2 hours. The precipitated product was collected by filtration, washed with MeOH+water 1:1, then with chilled MeOH. Dried on high vacuum. Y=209 mg of a deep yellow solid (90%). 1H-NMR(DMSO-d6, 400 MHz): δ 12.858 (s,1H), 7.780 (d, J=8.6 Hz, 1H), 7.476 (app dd, J=8.7 Hz, J=5.5 Hz, 2H), 7.386 (d, J=8.6 Hz, 1H), 7.126 (app t, J=8.6 Hz, 2H), 4.536 (s, 2H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-116.30 (m, 1F). Example 28 5-Chloro-3-(4-fluoro-benzyl)-8-methyl-9H-1,2,3a,4,9,10-hexaazacyclopenta[b]fluorene According to the general cyclization procedure (for Example 27), 0.60 mmol of 4-chloro-7-methyl-1H-indole-2,3-dione (117.5 mg) and 0.70 mmol of 5-(4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) was used for the preparation. Y=188 mg of a yellow solid (85.5%). 1H-NMR(DMSO-d6, 400 MHz): δ 12.388 (s,1H), 7.494 (m, 1H), 7.474 (m, 2H), 7.263 (d, J=7.8 Hz, 1H), 7.123 (app t, J=9.0 Hz, 2H), 4.520 (s, 2H), 2.443 (s, 3H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-116.36 (m, 1F). Example 29 5,8-Dichloro-3-(4-fluoro-benzyl)-6-methoxy-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorene According to the general cyclization procedure (for Example 27), 0.60 mmol of 4,7-dichloro-1H-indole-2,3-dione (148 mg) and 0.70 mmol of 5-(4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) was used for the preparation. Y=240 mg of a bright-red solid (96%). 1H-NMR(DMSO-d6, 400 MHz): 6 12.576 (s,1H), 7.634 (s, 1H), 7.473 (app dd, J=8.6 Hz, J=5.5 Hz, 2H), 7.119 (app t, J=8.6 Hz, 2H), 4.520 (s, 2H), 3.941 (s, 3H); 19F-NMR (DMSO-d6, 376.5 MHz): δ-116.32 (m, 1F). Example 30 3-(4-Fluoro-benzyl)-5,8-dimethyl-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorene According to the general cyclization procedure (for Example 27), 0.60 mmol of 4,7-dimethyl-1H-indole-2,3-dione (105 mg) and 0.70 mmol of (4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) in 2 mL of ethylene glycol was stirred at 125° C. overnight (18 hr). The mixture was cooled to room temperature, diluted with water (10 mL), stirred for 15 min. The precipitated product was collected by filtration, washed with MeOH+water 1:1. Dried on high vacuum. The crude product (187 mg) was suspended in anhydrous ethanol (6 mL), heated to reflux, sonicated while hot, allowed to cool overnight, filtered, washed with ice-cold methanol, filtered and dried on high vacuum. .Y=165 mg of a orange-brown solid (79.5%). MS+cESI: 347 (M+1). MS+cESI: 345 (M+1). 1H-NMR(DMSO-d6, 400 MHz): 6 12.094 (s,1H), 7.444 (dd, J=8.6 Hz, J=5.5 Hz, 2H), 7.344 (d, J=7.8 Hz, 1H), 7.127 (app t, J=9.0 Hz, 2H), 6.999 (d, J=7.8 Hz, 1H), 4.520 (m, 2H). 2.710 (s, 3H), 2.401 (s, 3H); 19F-NMR(DMSO-d6) 376.5 MHz): δ-116.41 (m, 1F). Example 31 4-(5-Chloro-8-methyl-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl)-phenol According to the general cyclization procedure (for Example 27), 0.60 mmol of 4-chloro-7-methyl-1H-indole-2,3-dione (117.5 mg) and 0.70 mmol of 4-(4,5-diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol (144 mg) was used for the preparation. Y=157 mg of a bright-yellow solid (71.5%). MS+APCI: 365(M+1), 729(2M+1). MS−APCI: 363(M−1), 727(2M−1). 1H-NMR(DMSO-d6, 400 MHz): 6 12.368 (s,1H), 9.236 (s, 1H), 7.476 (app d, J=8.6 Hz, 1H), 7.252 (app t, J=7.8 Hz, 3H), 6.662 (app d, J=8.6 Hz, 2H), 4.387 (s, 2H), 2.440 (s, 3H). Example 32 5-Chloro-3-(4-fluoro-benzyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-6-ol According to a cyclization procedure for Example 30, 0.60 mmol of 4-chloro-5-hydroxy-1H-indole-2,3-dione (118.5 mg) and 0.70 mmol of (4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) in 2 mL of ethylene glycol was stirred at 125° C. overnight (16 hr). Y=170 mg of a brown solid (77%). MS+cAPCI: 369(M+1), 737(2M+1). MS−cAPCI: 367(M−1), 735(2M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.078 (br s,1H),10.229 (s,1H), 7.477 (app dd, J=8.6 Hz, J=5.4 Hz, 2H), 7.319 (dAB, J=8.6 Hz,1H), 7.210 (dAB, J=8.6 Hz,1H), 7.477 (app dd, J=8.6 Hz, 2H), 4.512 (s, 2H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-116.40 (m, 1F). Example 33 5-Chloro-3-(4-hydroxy-benzyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-6-ol According to a cyclization procedure for Example 30, 0.60 mmol of 4-chloro-5-hydroxy-1H-indole-2,3-dione (118.5 mg) and 0.70 mmol of 4-(4,5-diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol (144 mg) in 2 mL of ethylene glycol was stirred at 125° C. overnight (16 hr). Y=178 mg of a light-brown solid (81%). MS+cAPCI: 367(M+1), 733(2M+1). MS−cAPCI: 365(M−1), 731(2M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.054 (br s,1H), 10.226 (br s,1H), 9.232 (s,1H) 7.317 (dAB, J=8.6 Hz,1H), 7.239 (app d, J=8.2 Hz, 2H), 7.206 (dAB, J=8.6 Hz,1 H), 6.658 (app d, J=8.7 Hz, 2H), 4.377 (s, 2H). Example 34 [(3 S)-3-Amino-pyrrolidin-1-yl]-[5-chloro-3-(4-fluoro-benzyl)-9H-1,2,3a,4,9,10,-hexaaza-cyclopenta[b]fluoren-6-yl]-methanone 4-Chloro-2,3-dioxo-2,3-dihydro-1H-indole-5-carboxylicacid (114 mg, 0.51 mmol) and 5-(4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (105 mg, 0.51 mmol) were dissolved in Ethanol. It was refluxed for 24 h. The reaction mixture was cooled to rt. The precipitate was filtered and washed with ethanol. The title compound was obtained in good purity. 1H NMR (400 MHz, d6-DMSO) δ 4.54 (s, 2H), 7.11-7.15 (m, 2H), 7.41 (d, J=8.6 Hz, 1H), 7.47-7.51 (m, 2H), 8.15 (d, J=8.6 Hz, 1H), 13.04 (vbr s, 1H); 19F NMR (377 MHz, d6-DMSO) δ-116.3 (m, 1F). 5-Chloro-3-(4-fluoro-benzyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorene-6-carboxylic acid (68.5 mg, 0.17 mmol), Pyrrolidin-3-yl-carbamic acid tert-butyl ester (49 mg, 0.26 mmol), HOBt (38.5 mg, 0.29 mmol), EDC (46 mg, 0.24 mmol), and TEA (57 μl, 0.41 mmol) were dissolved in DMF (3 mL). It was stirred for 24 h at rt. DMF was removed and dichloromethane was added. It was washed with saturated sodiumbicarbonate and dried over sodiumsulfate. The solvent was removed and the residue was purified by chromatotron (15% methanol in dichloromethane). The BOC group was cleaved with 10% TFA in Dichloromethane. The solvent was removed and the residue was lyophilized. The title compound was obtained as a fluffy yellow solid (59%). 1H NMR (400 MHz, d6-DMSO, mixture of two rotamers) δ 1.88-1.98 (m, 1H), 2.14-2.26 (m, 1H), 3.12-3.24 (m, 1H), 3.29-3.33 (m, 0.5H), 3.45 (dd, J=6.1, 11.2 Hz, 0.5H), 3.52-3.59 (m, 1H), 3.64-3.69 (m, 0.5H), 3.73-3.78 (m, 1H), 3.85 (br s, 0.5H), 4.46 (s, 2H), 7.05 (t, J=8.8 Hz, 2H), 7.38-7.42 (m, 3H), 7.63 (dt, J =1.6, 7.1 Hz, 1H), 7.94 (br s, 1.5H), 8.03 (br s, 1.5H), 12.56 (br s, 1H); 19F NMR (377 MHz, d6-DMSO) δ-74.4 (s, 3 F), −116.3 (m, 1 F); MS m/z (relative intensity, %) 465.3 ([M+1]+, 100). Example 35 4-[5,8-Dimethyl-6-(2-morpholin-4-yl-ethoxy)-9H-1 ,2,3a,4,9, 10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl]-phenol A mixture of 4,7-dimethyl-5-(2-morpholin-4-yl-ethoxy)-1H-indole-2,3-dione (121.6 mg, 0.4 mmol) and 4-(4,5-diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol (82 mg, 0.4 mmol) in EtOH (15 mL) was heated with stirring in a pressure tube at 120° C. for 72 h. The solvent was removed and the residue was purified with a flash silica gel chromatography (CH2Cl2:MeOH:NH4OH=100:7:0.7) to give the title compound as a pink solid (50 mg, 27%). 1H-NMR (400 MHz, DMSO-d6) δ 11.87 (s, 1H), 9.23 (s, 1H), 7.18 (d, 2H), 7.17 (s, 1H), 6.65 (d, 2H), 4.36 (s, 2H), 4.10 (t, 2H), 3.58 (t, 4H), 2.72 (t, 2H), 2.61 (s, 3H), 2.49 (m, 4H), 2.40 (s, 3H). MS (m/z) 474 [M+1]. Example 36 3-(4-Fluoro-benzyl)-5,8-dimethyl-6-(2-morpholin-4-yl-ethoxy)-9H-1 ,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorine A reaction analogous to that in Example 36 using 5-(4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine as one of the reactants gave 3-(4-Fluoro-benzyl)-5,8-dimethyl-6-(2-morpholin-4-yl-ethoxy)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorine (28%) as a pink solid. 1H-NMR (400 MHz, DMSO-d6) δ 11.91 (s, 1H), 7.42 (m, 2H), 7.20 (s, 1H), 7.12 (m, 2H), 4.51 (s, 2H), 4.11 (t, 2H), 3.58 (t, 4H), 2.72 (t, 2HO, 2.60 (s, 3H), 2.49 (m, 4H), 2.41 (s, 3H). MS (m/z) 476 [M+1]. Example 37 4-[6-(2-Diethylamino-ethyl)-5,8-dimethyl-9H-1 ,2,3a,4,9, 10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl]-phenol hydrochloride 0.60 mmol of 5-(2-Diethylamino-ethyl)4,7-dimethyl-1H-indole-2,3-dione hydrochloride (186.5 mg) and 0.70 mmol of 4-(4,5-diamino-4H-[1,2,4]triazol-3-ylmethyl)-phenol (144 mg) in 1.5 mL of ethylene glycol was stirred at 125° C. for 1 day. The mixture was cooled to room temperature, diluted with water (5 mL), stirred for 10 min. Allowed to crystallize in a refrigerator (+5° C.) overnight. The precipitated product was collected by filtration, washed with water (3×1 mL) and dried on high vacuum. Y=206 mg of a brownish-orange solid (71.5%). MS+cAPSCI: 444 (M+1). MS−cAPCI: 442 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.101 (s,1H), 10.471 (br s, 1H), 9.293 (s, 1H) 7.346 (s, 1H), 7.188 (app d, J=8.2 Hz, 2H), 6.676 (app d, J=8.2 Hz, 2H), 4,389 (s, 2H), 3.231-3.131 (br m, 8H), 2.790 (s, 3H), 2.394 (s, 3H), 1.287 (t, J=7.4 Hz, 6H). Example 38 4-[5,8-Dimethyl-6-(2-morpholin4-yl-ethyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl]-phenol hydrochloride According to the procedure for Example 37, 0.60 mmol of 5-(N-morpholino-2-ethyl)-4,7-dimethyl-1H-indole-2,3-dione (195 mg) and 0.70 mmol of 4-(4,5-diamino4H-[1,2,4]triazol-3-ylmethyl)-phenol (144 mg) in 1.5 mL of ethylene glycol was stirred at 125° C. for 1 day. Y=207.5 mg of a biege solid (70%). MS+cAPSCI: 458 (M+1). MS−cAPCI: 456 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.099 (br s,1H), 9.279 (s, 1H) 7.321 (s, 1H), 7.191 (app d, J=8.2 Hz, 2H), 6.674 (app d, J=8.2 Hz, 2H), 4.398 (s, 2H), 3.833 (br m, 6H), 3.115 (br m, 6H) 2.793 (s, 3H), 2.404 (s, 3H). Example 39 4-[5,8-Dimethyl-6-(2-pyrrolidin-1-yl-ethyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-3-ylmethyl]-phenol hydrochloride According to the procedure for Example 37, 0.60 mmol of 5-(N-pyrrolidino-2-ethyl)-4,7-dimethy-1H-indole-2,3-dione (185.5 mg) and 0.70 mmol of 4-(4,5-diamino4H-[1,2,4]triazol-3-ylmethyl)-phenol (144 mg) in 1.5 mL of ethylene glycol was stirred at 125° C. for 1 day. Y=191 mg of a biege solid (66.5%). MS+cAPSCI: 442 (M+1). MS−cAPCI: 440 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.102 (br s,1H), 10.653 (br s, 1H), 9.281 (s, 1H) 7.348 (s, 1H), 7.190 (app d, J=8.2 Hz, 2H), 6.674 (app d, J=8.2 Hz, 2H), 4.397 (s, 2H), 3.583 (very br m, 2H), 3.278 (br m, 2H), 3.098 (br m, 4H), 2.790 (s, 3H), 2.403 (s, 3H), 2.012 (br m, 2H), 1.940 (br m, 2H). Example 40 3-(4-Fluoro-benzyl)-5,8-dimethyl-6-(2-morpholin-4-yl-ethyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorine hydrochloride According to the procedure for Example 37, 0.60 mmol of 5-(N-morpholino-2-ethyl)-4,7-dimethyl-1H-indole-2,3-dione hydrochloride (195 mg) and 0.70 mmol of (4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) in 1.5 mL of ethylene glycol was stirred at 125° C. for 1 day. Y=149 mg of an orange solid (50%). MS+cAPSCI: 460 (M+1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.092 (br s,1H), 7.433 (app dd, J=8.7 Hz, J=5.5 Hz, 2H), 7.315 (s, 1 H), 7.125 (app t, J=9.0 Hz, 2H), 4.532 (s, 2H), 3.757 (very br m, 4H), 3.027 (very br m, 8H), 2.753 (s, 3H), 2.400 (s, 3H); 9 F-NMR(DMSO-d6, 376.5 MHz): δ-116.38 (m, 1F). Example 41 3-(4-Fluoro-benzyl)-5,8-dimethyl-6-(2-pyrrolidin-1-yl-ethyl)-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluorine hydrochloride According to the procedure for Example 37, 0.60 mmol of 5-(N-pyrrolidino-2-ethyl)-4,7-dimethyl-1H-indole-2,3-dione hydrochloride (185.5 mg) and 0.70 mmol of (4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) in 1.5 mL of ethylene glycol was stirred at 125° C. for 1 day. Y=87 mg of an orange solid (30%). MS+cAPSCI: 444 (M+1). MS−cAPCI: 442 (M−1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.136 (s,1H),10.674 (br s, 1H), 7.433 (app dd, J=8.6 Hz, J=5.5 Hz, 2H), 7.364 (s, 1H), 7.125 (app t, J=9.0 Hz, 2H), 4.539 (s, 2H), 3.584 (br m, 2H), 3.268 (br m, 2H), 2.771 (s, 3H), 2.410 (s, 3H), 2.037 (br m, 2H), 1.909 (br m, 2H), 19F-NMR (DMSO-d6, 376.5 MHz): δ-116.36 (m, 1 F). Example 42 Diethyl-{2-[3-(4-fluoro-benzyl)-5,8-dimethyl-9H-1,2,3a,4,9,10-hexaaza-cyclopenta[b]fluoren-6-yl]-ethyl}-amine hydrochloride 0.60 mmol of 5-(N,N-diethylamino-2-ethyl)-4,7-dimethyl-1H-indole-2,3-dione hydrochloride (186.5 mg) and 0.70 mmol of (4-fluoro-benzyl)-[1,2,4]triazole-3,4-diamine (145 mg) in 1.5 mL of ethylene glycol was stirred at 125° C. for 1 day. The mixture was cooled to room temperature, diluted with water (5 mL), and neat diethylamine 0.5 mL was added. Stirred for 3 hours, the precipitate was collected by filtration, washed with water and dried on highvac. The obtained free base was suspended in water (10 mL), 2M HCl 0.5 mL was added, heated to boil, sonicated briefly while hot and then allowed to crystallize in a refrigerator (+5° C.) overnight. The precipitate was collected by filtration, washed with ice-cold water (2×1 mL) and dried on high vacuum. Y=172 mg of an orange-biege solid (59.5%). MS+cAPCI: 446 (M+1). MS-cAPCI: 444 (M-1). 1H-NMR(DMSO-d6, 400 MHz): δ 12.135 (s,1H), 10.374 (br s, 1H), 7.432 (app dd, J=8.6 Hz, J=3.1 Hz, 2H), 7.375 (s, 1H), 7.125 (app t, J=9.0 Hz, 2H), 4.534 (s, 2H), 3.226 (br m, 4H), 3.133 (br m, 4H), 2.777 (s, 3H), 2.408 (s, 3H), 1.282 (t, J=7.4 Hz, 6H); 19F-NMR(DMSO-d6, 376.5 MHz): δ-116.37 (m, 1 F). Biological Examples The following assays are employed to find those compounds demonstrating the optimal degree of the desired activity. Assay Procedures. The following assays may be used to determine the level of activity and effect of the different compounds of the present invention on one or more of the PKs. Similar assays can be designed along the same lines for any PK using techniques well known in the art. Several of the assays described herein are performed in an ELISA (Enzyme-Linked Immunosorbent Sandwich Assay) format (Voller, et al., 1980, “Enzyme-Linked Immunosorbent Assay,” Manual of Clinical Immunology, 2d ed., Rose and Friedman, Am. Soc. Of Microbiology, Washington, D.C., pp. 359-371). The general procedure is as follows: a compound is introduced to cells expressing the test kinase, either naturally or recombinantly, for a selected period of time after which, if the test kinase is a receptor, a ligand known to activate the receptor is added. The cells are lysed and the lysate is transferred to the wells of an ELISA plate previously coated with a specific antibody recognizing the substrate of the enzymatic phosphorylation reaction. Non-substrate components of the cell lysate are washed away and the amount of phosphorylation on the substrate is detected with an antibody specifically recognizing phosphotyrosine compared with control cells that were not contacted with a test compound. The presently preferred protocols for conducting the ELISA experiments for specific PKs is provided below. However, adaptation of these protocols for determining the activity of compounds against other RTKs, as well as for CTKs and STKs, is well within the scope of knowledge of those skilled in the art. Other assays described herein measure the amount of DNA made in response to activation of a test kinase, which is a general measure of a proliferative response. The general procedure for this assay is as follows: a compound is introduced to cells expressing the test kinase, either naturally or recombinantly, for a selected period of time after which, if the test kinase is a receptor, a ligand known to activate the receptor is added. After incubation at least overnight, a DNA labeling reagent such as 5-bromodeoxyuridine (BrdU) or H3-thymidine is added. The amount of labeled DNA is detected with either an anti-BrdU antibody or by measuring radioactivity and is compared to control cells not contacted with a test compound. MET Transphosphorylation Assay This assay is used to measure phosphotyrosine levels on a poly(glutamic acid:tyrosine (4:1)) substrate as a means for identifying agonists/antagonists of met transphosphorylation of the substrate. Materials and Reagents: 1. Corning 96-well Elisa plates, Corning Catalog #25805-96. 2. Poly(glu, tyr) 4:1, Sigma, Cat. No; P 0275. 3. PBS, Gibco Catalog #450-1300EB 4. 50 mM HEPES 5. Blocking Buffer: Dissolve 25 g Bovine Serum Albumin, Sigma Cat. No A-7888, in 500 ml PBS, filter through a 4 μm filter. 6. Purified GST fusion protein containing the Met kinase domain, Sugen, Inc. 7. TBST Buffer. 8. 10% aqueous (MilliQue H2O) DMSO. 9. 10 mM aqueous (dH2O) Adenosine-5′-triphosphate, Sigma Cat. No. A-5394. 10. 2× Kinase Dilution Buffer: for 100 ml, mix 10 mL 1M HEPES at pH 7.5 with 0.4 mL 5% BSA/PBS, 0.2 mL 0.1M sodium orthovanadate and 1 mL 5M sodium chloride in 88.4 mL dH2O. 11. 4× ATP Reaction Mixture: for 10 mL, mix 0.4 mL 1M manganese chloride and 0.02 mL 0.1M ATP in 9.56 mL dH2O. 12. 4× Negative Controls Mixture: for 10 mL, mix 0.4 mL 1M manganese chloride in 9.6 mL dH2O. 13. NUNC 96-well V bottom polypropylene plates, Applied Scientific Catalog #S-72092 14. 500 mM EDTA. 15. Antibody Dilution Buffer: for 100 mL, mix 10 mL 5% BSA/PBS, 0.5 mL 5% Carnation Instant Milk® in PBS and 0.1 mL 0.1M sodium orthovanadate in 88.4 mL TBST. 16. Rabbit polyclonal antophosphotyrosine antibody, Sugen, Inc. 17. Goat anti-rabbit horseradish peroxidase conjugated antibody, Biosource, Inc. 18. ABTS Solution: for 1 L, mix 19.21 g citric acid, 35.49 g Na2HPO4 and 500 mg ABTS with sufficient dH2O to make 1 L. 19. ABTS/H2O2: mix 15 mL ABST solution with 2 μL H2O2 five minutes before use. 20. 0.2M HCl Procedure: 1. Coat ELISA plates with 2 μg Poly(Glu-Tyr) in 100 μL PBS, store overnight at 4° C. 2. Block plate with 150 μL of 5% BSA/PBS for 60 min. 3. Wash plate twice with PBS, once with 50 mM Hepes buffer pH 7.4. 4. Add 50 μl of the diluted kinase to all wells. (Purified kinase is diluted with Kinase Dilution Buffer. Final concentration should be 10 ng/well.) 5. Add 25 μL of the test compound (in 4% DMSO) or DMSO alone (4% in dH2O) for controls to plate. 6. Incubate the kinase/compound mixture for 15 minutes. 7. Add 25 μL of 40 mM MnCl2 to the negative control wells. 8. Add 25 μL ATP/MnCl2 mixture to the all other wells (except the negative controls). Incubate for 5 min. 9. Add 25 μL 500 mM EDTA to stop reaction. 10. Wash plate 3× with TBST. 11. Add 100 μL rabbit polyclonal anti-Ptyr diluted 1:10,000 in Antibody Dilution Buffer to each well. Incubate, with shaking, at room temperature for one hour. 12. Wash plate 3× with TBST. 13. Dilute Biosource HRP conjugated anti-rabbit antibody 1: 6,000 in Antibody Dilution buffer. Add 100 μL per well and incubate at room temperature, with shaking, for one hour. 14. Wash plate 1× with PBS. 15. Add 100 μl of ABTS/H2O2 solution to each well. 16. If necessary, stop the development reaction with the addition of 100 μl of 0.2M HCl per well. 17. Read plate on Dynatech MR7000 elisa reader with the test filter at 410 nM and the reference filter at 630 nM. MET Transphosphorylation Assay Results: Table 1 shows the IC50 values obtained for a number of compounds of the preferred embodiments of the invention. TABLE 1 Compound Example Number c-MET IC50 (μM) 17 0.018 18 0.036 19 0.012 20 0.046 21 0.01 22 0.035 23 0.46 24 0.022 25 0.055 26 0.025 34 0.042 35 0.028 36 0.56 One skilled in the art would readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent herein. The molecular complexes and the methods, procedures, treatments, molecules, specific compounds described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention are defined by the scope of the claims. It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. All patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Thus, for example, in each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group. For example, if X is described as selected from the group consisting of bromine, chlorine, and iodine, claims for X being bromine and claims for X being bromine and chlorine are fully described.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The following is offered as background information only and is not admitted to be prior art to the present invention. Protein kinases (“PKs”) are enzymes that catalyze the phosphorylation of hydroxy groups on tyrosine, serine and threonine residues of proteins. The consequences of this seemingly simple activity are staggering; cell growth, differentiation and proliferation, i.e., virtually all aspects of cell life in one way or another depend on PK activity. Furthermore, abnormal PK activity has been related to a host of disorders, ranging from relatively non-life threatening diseases such as psoriasis to extremely virulent diseases such as glioblastoma (brain cancer). The PKs can be conveniently broken down into two classes, the protein tyrosine kinases (PTKs) and the serine-threonine kinases (STKs). One of the prime aspects of PTK activity is their involvement with growth factor receptors. Growth factor receptors are cell-surface proteins. When bound by a growth factor ligand, growth factor receptors are converted to an active form which interacts with proteins on the inner surface of a cell membrane. This leads to phosphorylation on tyrosine residues of the receptor and other proteins and to the formation inside the cell of complexes with a variety of cytoplasmic signaling molecules that, in turn, effect numerous cellular responses such as cell division (proliferation), cell differentiation, cell growth, expression of metabolic effects to the extracellular microenvironment, etc. For a more complete discussion, see Schlessinger and Ullrich, Neuron 9:303-391 (1992), which is incorporated by reference, including any drawings, as if fully set forth herein. Growth factor receptors with PTK activity are known as receptor tyrosine kinases (“RTKs”). They comprise a large family of transmembrane receptors with diverse biological activity. At present, at least nineteen (19) distinct subfamilies of RTKs have been identified. An example of these is the subfamily designated the “HER” RTKs, which include EGFR (epithelial growth factor receptor), HER2, HER3 and HER4. These RTKs consist of an extracellular glycosylated ligand binding domain, a transmembrane domain and an intracellular cytoplasmic catalytic domain that can phosphorylate tyrosine residues on proteins. Another RTK subfamily consists of insulin receptor (IR), insulin-like growth factor I receptor (IGF-1R) and insulin receptor related receptor (IRR). IR and IGF-1R interact with insulin, IGF-I and IGF-II to form a heterotetramer of two entirely extracellular glycosylated subunits and two subunits which cross the cell membrane and which contain the tyrosine kinase domain. A third RTK subfamily is referred to as the platelet derived growth factor receptor (“PDGFR”) group, which includes PDGFR, CSFIR, c-kit and c-fms. These receptors consist of glycosylated extracellular domains composed of variable numbers of immunoglobin-like loops and an intracellular domain wherein the tyrosine kinase domain is interrupted by unrelated amino acid sequences. Another group which, because of its similarity to the PDGFR subfamily, is sometimes subsumed into the later group is the fetus liver kinase (“flk”) receptor subfamily. This group is believed to be made of up of kinase insert domain-receptor fetal liver kinase-1 (KDR/FLK-1), flk-1R, flk-4 and fms-like tyrosine kinase 1 (flt-1). Still another member of the growth factor receptor family is the vascular endothelial growth factor (“VEGF”) receptor subgroup. VEGF is a dimeric glycoprotein similar to PDGF but has different biological functions and target cell specificity in vivo. In particular, VEGF is presently thought to play an essential role is vasculogenesis and angiogenesis. A further member of the tyrosine kinase growth factor receptor family is the fibroblast growth factor (“FGF”) receptor subgroup. This group consists of four receptors, FGFR1-4, and seven ligands, FGF1-7. While not yet well defined, it appears that the receptors consist of a glycosylated extracellular domain containing a variable number of immunoglobin-like loops and an intracellular domain in which the tyrosine kinase sequence is interrupted by regions of unrelated amino acid sequences. Still another member of the tyrosine kinase growth factor receptor family is MET, often referred to as c-Met. c-met is also known as hepatocyte growth factor receptor or scatter factor receptor. c-Met is thought to play a role in primary tumor growth and metastasis. A more complete listing of the known RTK subfamilies is described in Plowman et al., DN&P, 7(6):334-339 (1994), which is incorporated by reference, including any drawings, as if fully set forth herein. In addition to the RTKs, there also exists a family of entirely intracellular PTKs called “non-receptor tyrosine kinases” or “cellular tyrosine kinases.” This latter designation, abbreviated “CTK,” will be used herein. CTKs do not contain extracellular and transmembrane domains. At present, over 24 CTKs in 11 subfamilies (Src, Frk, Btk, Csk, Abl, Zap70, Fes, Fps, Fak, Jak and Ack) have been identified. The Src subfamily appear so far to be the largest group of CTKs and includes Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk. For a more detailed discussion of CTKs, see Bolen, Oncogene, 8:2025-2031 (1993), which is incorporated by reference, including any drawings, as if fully set forth herein. The serine/threonine kinases, STKs, like the CTKs, are predominantly intracellular although there are a few receptor kinases of the STK type. STKs are the most common of the cytosolic kinases; i.e., kinases that perform their function in that part of the cytoplasm other than the cytoplasmic organelles and cytoskelton. The cytosol is the region within the cell where much of the cell's intermediary metabolic and biosynthetic activity occurs; e.g., it is in the cytosol that proteins are synthesized on ribosomes. RTKs, CTKs and STKs have all been implicated in a host of pathogenic conditions including, significantly, cancer. Other pathogenic conditions which have been associated with PTKs include, without limitation, psoriasis, hepatic cirrhosis, diabetes, angiogenesis, restenosis, ocular diseases, rheumatoid arthritis and other inflammatory disorders, immunological disorders such as autoimmune disease, cardiovascular disease such as atherosclerosis and a variety of renal disorders. With regard to cancer, two of the major hypotheses advanced to explain the excessive cellular proliferation that drives tumor development relate to functions known to be PK regulated. That is, it has been suggested that malignant cell growth results from a breakdown in the mechanisms that control cell division and/or differentiation. It has been shown that the protein products of a number of proto-oncogenes are involved in the signal transduction pathways that regulate cell growth and differentiation. These protein products of proto-oncogenes include the extracellular growth factors, transmembrane growth factor PTK receptors (RTKs), cytoplasmic PTKs (CTKs) and cytosolic STKs, discussed above. In view of the apparent link between PK-related cellular activities and wide variety of human disorders, it is no surprise that a great deal of effort is being expended in an attempt to identify ways to modulate PK activity. Some of these have involved biomimetic approaches using large molecules patterned on those involved in the actual cellular processes (e.g., mutant ligands (U.S. application Ser. No. 4,966,849); soluble receptors and antibodies (Application No. WO 94/10202, Kendall and Thomas, Proc. Nat'l Acad. Sci., 90:10705-10709 (1994), Kim, et al., Nature, 362:841-844 (1993)); RNA ligands (Jelinek, et al., Biochemistry, 33: 10450-56); Takano, et al., Mol. Bio. Cell, 4:358A (1993); Kinsella, et al., Exp. Cell Res., 199: 56-62 (1992); Wright, et al., J. Cellular Phys., 152:448-57) and tyrosine kinase inhibitors (WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., Proc. Am. Assoc. Cancer Res., 35:2268 (1994)). In addition to the above, attempts have been made to identify small molecules which act as PK inhibitors. For example, bis-monocylic, bicyclic and heterocyclic aryl compounds (PCT WO 92/20642), vinylene-azaindole derivatives (PCT WO 94/14808) and 1-cyclopropyl-4-pyridylquinolones (U.S. Pat. No. 5,330,992) have been described as tyrosine kinase inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), quinazoline derivatives (EP Application No. 0 566 266 A1), selenaindoles and selenides (PCT WO 94/03427), tricyclic polyhydroxylic compounds (PCT WO 92/21660) and benzylphosphonic acid compounds (PCT WO 91/15495) have all been described as PTK inhibitors useful in the treatment of cancer.
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<SOH> SUMMARY OF THE INVENTION <EOH>The invention relates to a compound of the formula I: wherein: R 1 is an aryl or heteroaryl group, wherein said aryl or heteroaryl group is unsubstituted or optionally substituted with one or more substituents selected from the group consisting of halogen, —OH, —OR 8 , —COR 8, —COOR 8 , —CONR 8 R 9 , —NR 8 R 9 , —CN, —NO 2 , —S(O) 2 R 8 , —SO 2 NR 8 R 9 , —CF 3 , lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl and aryl; each R 2 and R 3 is independently selected from the group consisting of hydrogen, halogen, —OH, —OR 7 , —NR 7 R 8 , —CN, —COR 8 , —COOR 8 , —CONR 8 R 9 , —CF 3 , lower alkyl, cycloalkyl, heterocycle, alkenyl and alkynyl; or R 2 and R 3 , together with the carbon atom to which they are attached can form a cycloalkyl or heterocycle; R 4 , R 5 , R 6 , and R 7 are independently selected from the group consisting of hydrogen, halogen, —OR 8 , —COR 8 , —COOR 8 , —CONR 8 R 9 , —NR 8 R 9 , —CN, —NO 2 , —S(O) n R 6 (wherein n is 0, 1 or 2), —SO 2 R 7 R 8 , —CF 3 , lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl, and aryl; and each R 8 and R 9 is independently selected from the group consisting of hydrogen, lower alkyl, cycloalkyl, heterocycle, allkenyl, alkynyl, aryl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl or R 8 and R 9 together with the atom to which they are attached form a heteroalicyclic ring optionally substituted with a group selected from the group consisting of alkyl, —OH and amino; and p is 1, 2, 3, 4 or 5, it being understood that when p is an integer greater than 1, the R 2 and R 3 groups on each carbon atom may be the same as or different from the R 2 and R 3 groups on any adjacent carbon atom; or a pharmaceutically acceptable salt thereof. In a preferred embodiment, the variable p in a compound of formula I is 1. In another preferred embodiment, the aryl group on the compound of formula I is phenyl. In still another preferred embodiment the aryl group on the compound of formula I is a phenyl group substituted with an —OH or a halo group. The invention further relates to a compound of formula II: wherein: each R 10 is independently selected from the group consisting of halogen, —OH, —OR 8 , —COR 8 , —COOR 8 , —CONR 8 R 9 , —NR 8 R 9 , —CN, —NO 2 , —S(O) 2 R 8 , —SO 2 NR 8 R 9 , —CF 3 , lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl and aryl; q is 1, 2, 3, 4 or 5; G is nitrogen or carbon; each R 2 and R 3 is independently selected from the group consisting of hydrogen, halogen, —OH, —OR 7 , —NR 7 R 8 , —CN, —COR 8 , —COOR 8 , —CONR 8 R 9 , —CF 3 , lower alkyl, cycloalkyl, heterocycle, alkenyl and alkynyl; or R 2 and R 3 , together with the carbon atom to which they are attached can form a cycloalkyl or heterocycle; R 4 , R 5 , R 6 , and R 7 are independently selected from the group consisting of hydrogen, halogen, —OR 8 , —COR 8 , —COOR 8 , —CONR 8 R 9 , —NR 8 R 9 , —CN, —NO 2 , —S(O) n R 8 (wherein n is 0, 1 or 2), —SO 2 R 8 R 9 , —CF 3 , lower alkyl, cycloalkyl, heterocycle, alkenyl, alkynyl, and aryl; and R 8 and R 9 are selected from the group consisting of hydrogen, lower alkyl, cycloalkyl, heterocycle, allkenyl, alkynyl, aryl, aminoalkyl, alkylaminoalkyl, and dialkylaminoalkyl or R 8 and R 9 together with the atom to which they are attached form a heteroalicyclic ring optionally substituted with a group selected from the group consisting of alkyl, —OH and amino; and p is 1, 2, 3, 4 or 5, it being understood that when p is an integer greater than 1, the R 2 and R 3 groups on each carbon atom may be the same as or different from the R 2 and R 3 groups on any adjacent carbon atom; or a pharmaceutically acceptable salt thereof. In a preferred embodiment, the variable p in the compound of formula II is 1. In another preferred embodiment, R 10 in the compound of formula II is —OH or halo and q is 1. In still another preferred embodiment, the variable G in the compound of formula II is nitrogen. In yet another preferred embodiment, the compound of formula I or II is a compound selected from the group consisting of: a pharmaceutically acceptable salt thereof. In still another preferred embodiment, the compound of formula I or II is: The invention further relates to a method for treating a c-Met related disorder with a compound of formula I or II. In a preferred embodiment, the c-Met related disorder is a cancer. In another preferred embodiment, the cancer is selected from the group consisting of breast cancer, lung cancer, colorectal cancer, prostate cancer, pancreatic cancer, glioma, liver cancer, gastric cancer, head cancer, neck cancer, melanoma, renal cancer, leukemia, myeloma, and sarcoma. The invention still further relates to a pharmaceutical composition comprising a compound of formula I or II or pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient. detailed-description description="Detailed Description" end="lead"?
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20040629
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20060502
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20050120
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59393.0
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BALASUBRAMANIAN, VENKATARAMAN
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TETRACYCLIC COMPOUNDS AS C-MET INHIBITORS
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UNDISCOUNTED
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ACCEPTED
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10,878,833
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ACCEPTED
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Sleeve-like knitted structure for use as a castliner
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A castliner in the form of a three-dimensionally knitted sleeve comprises a microdenier yarn, and/or a spandex yarn, in particular, a spandex yarn having a flatter stress-strain curve than traditional spandex yarns. The use of the microdenier yarn contributes to the superior cushioning effect. The stretch and recovery properties of the particular spandex yarn contribute to superior fit and reduction of pressure points on the limb or body part to which the castliner is applied. Furthermore, the castliner is rendered water resistant and has significantly improved antimicrobial properties, both of which reduce incidents of skin irritation and unpleasant smell. As a result, the patient wearing the castliner of the invention is able to bathe and get wet without otherwise replacing the hard casting and castliner after such events.
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1. A castliner for use beneath an orthopedic cast comprising a microdenier yarn. 2. The castliner of claim 1, wherein the castliner further comprises spandex yarn. 3. The castliner of claim 2, wherein the spandex yarn comprises about 2 to about 20 percent by weight of the castliner. 4. The castliner of claim 2, wherein the spandex yarn has a stress-strain curve as shown by reference numerals 210a and 210b in FIG. 3. 5. The castliner of claim 1, characterized by a moisture vapor transmission rate of at least 800 grams per square meter per day; measured when the castliner is unstretched. 6. The castliner of claim 1, further comprising a fluorochemical treatment on the surface of the castliner. 7. The castliner of claim 6, wherein the castliner is characterized by a water uptake of less than 200 percent. 8. The castliner of claim 6, characterized by a drying time measured in open air of less than 5 hours. 9. The castliner of claim 6, characterized by a water contact angle greater than 140 degrees. 10. The castliner of claim 6, characterized by a water repellency rating of about 6 and greater. 11. The castliner of claim 1, characterized by an antimicrobial property characterized by a reduction in the growth rate of bacteria by at least log10(2). 12. A castliner for use beneath an orthopedic cast, comprising a spandex yarn having a stress-strain curve as shown by reference numerals 210a and 210b in FIG. 3. 13. The castliner of claim 12, further comprising a microdenier yarn knitted with the spandex yarn. 14. The castliner of claim 12, wherein the microdenier yarn is selected from the group consisting of polyester and nylon. 15. The castliner of claim 13, wherein the spandex yarn and the microdenier yarn are knitted together in a pattern selected from the group consisting of checkerboard, ribbed, double ribbed, and diamond. 16. The castliner of claim 13, wherein the spandex yarn comprises about 2 to 20 percent by weight of the castliner. 17. The castliner of claim 13, further comprising a fluorochemical treatment on the surface of the castliner. 18. A castliner in the form of a three-dimensionally knitted tubing for use beneath an orthopedic cast, comprising an acrylic yarn treated with a phase change material. 19. The castliner of claim 18, further comprising a spandex yarn knitted with the acrylic yarn. 20. A castliner in the form of a three-dimensionally knitted tubing for use beneath an orthopedic cast, comprising a microdenier polyester yarn knitted with a spandex yarn in a checkerboard pattern.
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CROSS-REFERENCE TO RELATED APPLICATION This application claims benefit of priority from Provisional Application No. 60/484,445 filed Jul. 2, 2003. FIELD OF THE INVENTION The present invention relates to a castliner, and particularly to a sleeve-like knitted structure, for use as a castliner having superior cushioning and enhanced comfortable conformance to the body, as well as exhibiting antimicrobial properties, decreased water uptake and an enhanced moisture transmission rate. More particularly the invention relates to a three-dimensional knitted sleeve adapted for use as a castliner and made from particular synthetic polymer fibers and knit in selected patterns. BACKGROUND OF THE INVENTION It is known to employ a cotton knit sock (e.g., single jersey knit) as a first layer and cotton or poly/cotton webbing for cushioning (also called padding) as a second layer under a hard shell casting material. Known casting materials are either of fiberglass or plaster-of-paris. In use, the known castliner comprises a cotton jersey sleeve, which is pulled over the limb being treated, and a cotton webbing wrapped around the limb. Typically, some skill is required for application of the castliner of this known type. Particular skill is needed during application of the layers of cotton webbing, which is cumbersome to apply. Especially important is the required thickness of cotton webbing which ultimately protects the limb during the cast removal process. A particular disadvantage of such known castliners is their poor water repellency and moisture transmission rate. Water retention by known castliners fosters the growth of bacteria causing patient complaints about: unpleasant odors, itching, and general discomfort. An improvement to the foregoing known cotton cast lining is described in U.S. Pat. No. 5,540,964 to Mallen. Mallen discloses a cast lining which is capable of transporting moisture from beneath the cast to the air space within the cast and ultimately to the outside area. In one embodiment of the Mallen invention a fabric is formed from a blend of hydrophobic synthetic fibers (e.g., polyester) and a second fiber (spandex). This fabric is constructed into a tube with or without open ends and used as castliner beneath an orthopedic cast. Mallen's cast lining tube is then made “hydrophilic” according to methods disclosed therein. In general, the Mallen fabric conforms closely to the limb being treated due to the elastic fiber content of the tubular cast lining. Mallen specifically discloses use of LYCRA® (branded spandex from INVISTA S.à r.l. of Wilmington, Del.) in its construction. Applicants have found various prior art cast lining materials disadvantageous in several modes of performance. First, jersey knit sleeve and cotton webbing can be difficult for unskilled casting room operators to apply uniformly. Second, the moisture absorption of these sleeve and webbing liners is high. Third, the sleeve and webbing lining can be stiff and can provide pressure points at joints especially. The Mallen (U.S. Pat. No. 5,540,964) cast lining is an improvement in conformance to the limb shape. It would be desirable to improve cushioning and moisture transmission rate while minimizing the pressure points caused by elastic yarns in the construction. Typically, points of increased pressure on the limb are present in areas of the limb joints and where the limb changes diameter most abruptly. Thus, a longstanding unmet need for a sleeve-like knitted castliner without the deficiencies of the prior art exists. SUMMARY OF THE INVENTION The present invention provides a castliner in the form of a three-dimensionally knitted tubing for use beneath an orthopedic cast with enhanced cushioning and comfortable conformance to the body. In addition, the sleeve-like knitted castliner of the present invention may provide enhanced moisture transmission rate, antimicrobial properties, and decreased water uptake. Moreover, the sleeve-like knitted castliner of the present invention may be easily and readily applied to limb or body portion in treatment by a relatively unskilled person. The present invention provides a sleeve-like knitted castliner for use beneath an orthopedic cast, comprising a micro-denier yarn. The invention further includes a castliner comprising a spandex yarn having a specified stress/strain curve defining the elastic modulus of the spandex yarn. A preferred castliner comprises a spandex yarn in an amount of about 2 to about 20 percent by weight of the total castliner. A preferred castliner comprises LYCRA® 902C or LYCRA® 906 brand spandex fiber available from INVISTA S.à r.l. of Wichita, Kans. and Wilmington, Del. The sleeve-like knitted castliner of the invention provides enhanced cushioning as compared to castliners of the prior art, and conforms tightly to the limb or body portion under treatment. Further in accordance with the present invention, there is provided a sleeve-like knitted castliner for use beneath an orthopedic cast, comprising an acrylic yarn treated with a phase change material. This castliner may also include a spandex yarn. BRIEF DESCRIPTIONS OF THE DRAWINGS FIG. 1 is a photograph of the castliner of the present invention showing both the inside and the outside of its knitted tubular structure. FIG. 2 is a graph showing the stress-strain curves for conventional spandex yarn and for LYCRA® Soft brand spandex fiber, which is an alternative spandex yarn. FIG. 3 is a graph showing a stress-strain curve for LYCRA® Soft brand spandex fiber. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention provides a castliner for use beneath an orthopedic cast. Such a castliner is shown generally at 100 in FIG. 1. The castliner comprises a microdenier yarn. The term microdenier means having a single filament denier of less than one, or a decitex (dtex) of 1.1 or less. The use of a microdenier yarn provides superior cushioning and comfort as compared to yarns of the prior art. The microdenier yarn may be polyester or nylon. Alternatively, the microdenier yarn may be acrylic. Suitable polyester microfiber yarns are those with yarn counts such as 55 dtex and 100 filaments and 78 dtex and 100 filaments known as MICROMATTIQUE® (Type 935T from INVISTA S.à r.l., Wilmington, Del.) and used typically as a 2 ply yarn in a preferred construction. The castliner may be in the form of a three-dimensional knitted tubing. By “three-dimensional” is meant that the castliner has some degree of depth to it, due to the cushioning characteristics imparted by the microdenier yarn. Further in accordance with the present invention, the castliner of the present invention may additionally comprise a spandex yarn, elastane yarn or polyester bicomponent yarns known as ELASTERELL-P™ from INVISTA™ of Wilmington, Del. The terms spandex and elastane are used interchangeably in the art. The spandex yarn is knitted with the microdenier yarn. An example of a branded spandex yarn suitable for use with the present invention is LYCRA®, sold by of INVISTA™ of Wilmington, Del. Such spandex yarns will be referred to hereinafter as traditional spandex yarns. Traditional spandex yarns such as LYCRA® have a dtex of about 10 to about 500. The castliner of the present invention may alternatively comprise a spandex yarn which is made from a filament characterized by a flatter stress/strain curve than the filament of the spandex yarn described in the previous paragraph. Such yarns will be referred to hereinafter as alternative spandex yarns. Examples of such alternative spandex yarns suitable for use with the present invention are LYCRA® 902C and LYCRA® 906, also sold by INVISTA™. LYCRA® 902C and LYCRA® 906 are copolyether based spandex with a combination of high elongation and flat stress-strain behavior and the low hysteresis in comparison with other commercially available spandex filaments with LYCRA® high unload power. To illustrate the difference between traditional LYCRA® yarns and LYCRA® 902C, reference is made to FIG. 2. FIG. 2 is graph of the stress-strain curves for a traditional spandex filament, and for LYCRA® 902C. Conventional LYCRA® filaments may have a stress-strain curve represented by 200a and 200b. LYCRA® 902C has a stress-strain curve represented by 210a and 210b. The latter stress-strain curve, 210a and 210b, is flatter than the stress-strain curve 200a and 200b. This distinction is based on the relative slope of the corresponding curves labeled 200a and 210a vs. curves 200b and 210b. For LYCRA® Soft brand spandex, the load and unload portions of the stress-strain curve can be substantially parallel within an elongation range of from about 300% to about 500%. The stress or force acting on the spandex filament, straining the filament, follows two different paths: path 200a (or 210a) while elongating and path 200b (or 210b) while retracting. This difference in path “a” and path “b” is known in the art as the hysteresis of the stress-strain curve. As a result of this low hysteresis in the stress-strain curve of the yarn of the present invention, pressure on the castliner treated limb is reduced for those points where the castliner is more greatly stretched versus traditional spandex yarns. The modulus of elasticity is the initial slope of the stress-strain curve. It should be noted that a castliner made from alternative spandex yarns will also have a unique stress/strain curve which may be distinct from the stress/strain curve of the filament. In any case, the stress/strain curve as described above quantifies the stretch and recovery properties. Regardless of whether traditional or alternative spandex yarns are used, the use of spandex yarns provides stretch and recovery properties to the cast liner. The spandex yarn, either traditional or alternative, typically comprises about 2 to about 20 percent by weight of the castliner. The spandex yarns used with the present invention, either traditional or alternative, may have covering filaments, such as nylon. In one alternative embodiment of the present invention, the spandex yarn may be knitted with an acrylic yarn, instead of a nylon or polyester yarn. In this embodiment, the acrylic yarn may contain a phase-change material. Such a material is a mixture of different chain-length hydrocarbons, and is commercially available from OUTLAST®, 6235 Lookout Road, Boulder, Colo. 80301, USA. The use of a phase change material (PCM) helps to reduce temperature spikes for the user, and to reduce sweat, thus making a castliner of the present invention more comfortable for the wearer. The castliner of the present invention may be constructed in the form of a circular knitted tubing using a seamless knitting machine. A suitable machine is the Santoni, SM8-8TOP, commercially available from Santoni of Italy. The seamless circular knitting machine is set to operate with 10 needles in the up position and 10 needles in the down position for the typical constructions used herein; but many variations know to the skilled practitioner of circular knitting are possible. In cases where the castliner knit tubing is being adapted for a finger castliner or for a full-body castliner, the numbers of needles used in either up or down positions is varied between about 2 to about 20. Patterns selected for the knit construction include a chess board, ribbed, doubled ribbed, or diamond patterns. In general, these patterns are three-dimensional knit structures. The inset of FIG. 1 illustrates a checkerboard pattern at 100a. In a preferred embodiment, a circular knitted tubing may be knitted into a checkerboard pattern from polyester yarns of 1.1 decitex (dtex) and less and from LYCRA® yarns, having covering filaments of nylon typically, the LYCRA® having a dtex of about 10 to about 500. In order to achieve very low levels of water uptake in the castliner rendering the castliner material hydrophobic, it may be advantageous to provide a fluorochemical surface treatment to the castliner. This treatment may provide the castliner with a water uptake of less than 200 percent, generally less 150 percent. A suitable fluorochemical treatment is provided by a TEFLON® fluoropolymer resin finish (known as ZONYL® 555 and available from E. I. DuPont.de Nemours and Company, Inc., Wilmington, Del., USA) applied to the yarns comprising the knitted tubing. A treatment with ZONYL® 555 padded onto the castliner material in an amount from about 2.5% to 7.5% by weight was found to be effective. The use of the fluorochemical surface treatment also improves drying time. Typically, the drying time of the cast liner of the present invention, measured in open air, is less than five hours. In addition, the use of the fluorochemical surface treatment also minimizes water contact with the patient. This measured by water contact angle, which, with the present invention, is greater than 140 degrees. This minimized water contact is also measured by water repellency. The castliner of the present invention is characterized by a water repellency rating of about 6 and greater. The castliner of the present invention may also include an antimicrobial agent. Such agent may be included in the yarn. Examples of yarns containing silver as an antimicrobial agent include a sheath-core yarn having silver particles in the sheath, FossFiber® with AgION™ commercially available from Foss Manufacturing Company, Inc., Hampton, N.H., Xstatic® yarn, available from SAUQUOIT Industries, Inc., Scranton, Pa., USA having silver deposited on the yarn, or A.M.Y.™ yarn, commercially available from UNIFI Inc., Greensboro, N.C., USA, having silver spun into the yarn polymer. Alternatively, a topical finish may be used on the castliner. In any case, the castliner of the present invention is characterized by a reduction in the growth rate of bacteria by at least log10(2) based on test methods know as ASTM E2149-01 “Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions” and MTCC Test Method 100-1999 “Assessment of Antibacterial Finishes on Textile Materials.” The knitted construction and the materials of the castliner of the present invention may provide improved moisture vapor transmission. A castliner of the present invention may be characterized by a moisture vapor transmission rate of at least 800 grams per square meter per day, measured when the castliner is stretched. This moisture vapor transmission rate can enhance the antimicrobial properties of the castliner as described above. The castliner of the present invention, constructed as described above, provides superior cushioning, comfort and simple application. In particular, the use of a microdenier yarn may contribute to the cushioning effect. The stretch and recovery properties of the spandex yarn of the castliner may contribute to provide a castliner having superior fit and reduction of pressure points on the limb or body part to which the castliner is applied. Furthermore, the castliner may be rendered water resistant and significantly improved in antimicrobial properties which reduce incidents of skin irritation and unpleasant smell. As a result, the patient wearing the castliner of the invention is able to bathe and get wet without otherwise replacing the hard casting and castliner after such events. The invention will be described in greater detail with reference to the following examples which are intended to illustrate the invention without restricting the scope thereof. Test Methods Water (Moisture) Uptake Test Method In this test method a circular sample 2 inches (51 mm) in diameter was cut. This circular sample was weighed (initial dry weight). Each sample was submerged in cool water for 30 seconds, force was applied to keep the sample submerged. By hand the sample was squeezed to force as much water from it as possible. The squeeze dry sample was weighed again (final wet weight). The average of three trials were taken. In the case of fluorochemical treated samples the hand squeeze procedure was omitted as these could be shaken to remove excess water. The difference between the initial weight and the wet weight expressed as a percentage increase in weight was called the moisture pickup. Water Repellency Rating (DuPont Water Drop Test) This test determines a finished fabric's resistance to wetting by aqueous liquids. Drops of water-alcohol mixtures of varying surface tensions are placed on the fabric, and the extent of surface wetting is determined visually. This test provides a rough index of aqueous stain resistance. Generally, the higher the water repellency rating, the better the finished fabric's resistance to staining by water-based substances. In this test, a fabric was placed face up on white blotting paper on a flat horizontal surface. Beginning with Test Liquid No. 1, which was a mixture of 2% isopropyl alcohol and 98% distilled water, drops were placed approximately 5 mm in diameter or 0.05 ml in volume on the test fabric in three locations. The drops were observed for 10 seconds from an approximate 45° angle. If at least two of the three drops do not penetrate or wet the fabric and do not show wicking around the drops, the drops of test Liquid No. 2, which was a mixture of 5% isopropyl alcohol and 95% distilled water, were placed on an adjacent site, and the step of placing the drops on the test fabric in three locations was repeated. The steps of observing the drops, and adding drops of test Liquid No. 2 were repeated, until at least two of the three drops had wet or showed wicking into the fabric within 10 seconds. The steps of observing the drops and adding drops were repeated for test Liquid No. 3, which was a mixture of 10% isopropyl alcohol and 90% distilled water, for test Liquid No. 4, which was a mixture of 20% isopropyl alcohol and 80% distilled water, for test Liquid No. 5, which was a mixture of 30% isopropyl alcohol and 70% distilled water, and for test Liquid No. 6, which was a mixture of 40% isopropyl alcohol and 60% distilled water. The fabric's water repellency rating was the highest numbered liquid for which at least two of the three drops did not wet or wick into the fabric. Drying Time Measured in Open Air In this test method a circular sample 2 inches (51 mm) in diameter was cut. This circular sample was weighed (initial dry weight). Each sample was submerged in cool water for 30 seconds, force was applied to keep the sample submerged exactly as had been done for the moisture pickup test method. While holding each sample with forceps the sample was shaken 3 times to expel excess water. After shaking the wet samples were weighed and then placed on a plastic sheet and allowed to air dry. The weight of each sample was recorded once per hour for a total of 3 hours. The difference in weight between the initial weight and weight after each hour of the test was the water loss per hour. This weight loss was expressed in grams of water evaporated from the samples and as a percentage loss in weight due to evaporation. Water Contact Angle The water contact angle method used was along the lines of ASTM D724-99 Standard Test Method for Surface Wet-Ability of Paper (Angle-of-Contact Method). Using a microscope and angle measuring comparators the contact angle was estimated visually. The measurement was repeated with a soap solution of the MTCC standard detergent 124 powder made up to 2 weight % in distilled water at 38° C. for those cases where the contact angle was quite high. Moisture Vapor Transmission Rate (MVTR) Moisture vapor transmission rate, or MVTR, is determined according to ASTM Standard E96-66, Procedure BW (Inverted Water Method at 23 C). Standard E96-66 permits determination of the rate of water vapor transmission of materials in sheet form. Procedure BW is for use when materials to be tested may in service be wetted on one surface but under conditions where the hydraulic head is relatively unimportant and moisture is governed by capillary and water vapor diffusion forces. ASTM Standard E96-66 provides further details of how to perform the measurements. Salzmann Medico Sub-bandage Pressure Monitor MST Mark 3 (Salzmann Group, St. Gallen, Switzerland) was used to evaluate pressure points as the castliner sleeve was fitted to the limb under treatment. In all cases a Size 4 mannequin leg form was used in testing. Pressure points could be measured in 6 separate areas of the leg, denoted as b, b1, c, d, f, and g. In not all cases did the castliner sleeve cover the entire mannequin leg form, as a result, fewer than 6 separate measurements may have been taken. Pressure is reported from the Salzmann MST Mark 3 in units of mm of mercury (mmHg). Fabric Stretch and Recovery Fabric stretch and recovery for a stretch woven fabric is determined using a universal electromechanical test and data acquisition system to perform a constant rate of extension tensile test. A suitable electromechanical test and data acquisition system is available from Instron Corp, 100 Royall Street, Canton, Mass., 02021 USA. Two fabric properties are measured using this instrument: fabric stretch and the fabric growth (deformation). The available fabric stretch is the amount of elongation caused by a specific load between 0 and 30 Newtons and expressed as a percentage change in length of the original fabric specimen as it is stretched at a rate of 300 mm per minute. The fabric growth is the unrecovered length of a fabric specimen which has been held at 80% of available fabric stretch for 30 minutes then allowed to relax for 60 minutes. Where 80% of available fabric stretch is greater than 35% of the fabric elongation, this test is limited to 35% elongation. The fabric growth is then expressed as a percentage of the original length. The elongation or maximum stretch of stretch woven fabrics in the stretch direction is determined using a three-cycle test procedure. The maximum elongation measured is the ratio of the maximum extension of the test specimen to the initial sample length found in the third test cycle at load of 30 Newtons. This third cycle value corresponds to hand elongation of the fabric specimen. Antimicrobial Activity The antimicrobial activity of the castliner of was measured using several test methods, these were: ASTM E2149-01 “Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions” and AATCC Test Method 100-1999 “Assessment of Antibacterial Finishes on Textile Materials” and the “Shake-Flask Test” with test # Dow 923, known in the art as the Shake-Flask test. All of these testing procedures were made available as a service from NAMSA, 6750 Wales Road, Northwood, Ohio 43619, USA with an ISO 10993 certificate of compliance. EXAMPLES Example 1 Part a—A second castliner sample of the invention was constructed from a double ply of 70 denier 100 filament COOLMAX® polyester yarn (INVISTA™ North America Inc.) and 8% by weight of 70 denier LYCRA® brand spandex single covered with 20 denier 7 filament nylon. Part b—A first castliner sample of the invention was constructed from a double ply of 70 denier 100 filament COOLMAX® polyester yarn (INVISTA™ North America Inc. and 8% by weight of 20 denier LYCRA® brand spandex single covered with 20 denier 7 filament nylon. Part c—A third castliner sample of the invention was constructed from a double ply of 70 denier 100 filament COOLMAX® polyester yarn (INVISTA™ North America Inc.) and 8% by weight of 40 denier LYCRA® brand spandex single covered with 20 denier 7 filament nylon. The three samples (a, b and c) were tested using the moisture uptake test method using a circular sample 2 inches (51 mm) in diameter cut from each tubing. Each of the samples (a, b and c) was also separately treated with a fluorochemical finish, ZONYL® 555 by a padding method. The 3 samples untreated with fluorochemical finish were controls for the 3 treated samples. The following table summarizes these results for moisture uptake by the materials of the castliner. ZONYL ® initial squeezed 555 (% by weight in weight % moisture Sample weight) grams ave. pickup a 0 1.628 5.379 330.41 b 0 1.026 3.468 338.01 c 0 1.380 4.510 326.79 a 2.5 1.8 2.947 163.70 b 5.0 1.466 1.909 130.20 c 7.5 1.568 1.911 121.88 These data show that the fluorochemical (ZONYL® 555) treated samples all performed with a moisture pickup of less than half that moisture pickup of the untreated samples. A castliner tubing of fluorochemical treated material would be expected to be highly moisture resistant. In order to estimate the amount of fluorochemical applied to the castliner, the treated samples were analyzed for total fluoride ion by ion chromatography (IC) using the standard methods know to practitioners in the art. These results for the ZONYL® treated materials are given in the following table. Total Fluorine as ZONYL ® 555 fluoride ion Sample (% by weight) (parts per million) a 2.5 1375 b 5.0 2010 All of the fluorochemical treated samples were measure for their contact angle with a water droplet (along the lines of the ASTM D724-99 method). In all samples a, b, and c the contact angle was not measurable with distilled water. The measurements were repeated with soap solution (AATCC standard detergent 124 powder; 2 weight % in distilled water). In all samples a, b, and c the soap solution contact angle was greater than 140 degrees of arc. Evidently, the very high surface energy imparted by the fluorochemical treatment to the castliner materials of construction prevented and substantial water wetting. Drying time measured in open air: In this test method a circular sample 2 inches (51 mm) in diameter was cut. This circular sample was weighed (initial dry). The three samples (a, b and c) were tested using the test method for drying time measured in open air. Identically to the moisture uptake method a circular sample 2 inches (51 mm) in diameter cut from each tubing. Each of the samples (a, b and c) was also separately treated with a fluorochemical finish, ZONYL® 555 by a padding method. The 3 samples untreated with fluorochemical finish were controls for the 3 treated samples. The following table summarizes these results for drying time measured in open air by the materials of the castliner tubing. These data show again that very little moisture is acquired by the fluorochemical treated castliner material and that these treated samples air dry at a substantially constant rate over the 3 hour measurement period. % water ZONYL ® uptake % water 555 (% (measured % water % water loss by after loss after loss after after 3 Sample weight) shaking) 1 hour 2 hours hours a 0 441.7 34.8 22.9 29.7 b 0 672.7 51.2 33.7 44.6 c 0 315.7 33.3 23.2 28 a 2.5 256.8 25.9 19.9 21.9 b 5.0 114. 30.8 20.4 23.1 c 7.5 7.5 9.6 0.0 0.0 These three samples were tested for interface pressure points using Salzmann Medico MST Mark 3 tester and a Size 4 mannequin leg form. Six potential leg pressure points could be measured, denoted as points b, b1, c, d, f, and g in the Salzmann Medico MST MKIII measurement protocol. Pressure points b and b1 corresponded to ankle and subcalf portions of the leg, c and d corresponded to calf and knee portions, while measurements f and g corresponded to the largest diameter portions of the thigh. Salzmann Medico MST MKIII Measurement Summary Sample a Sample b Sample c Measurement pressure pressure Pressure point (Size 4 leg) (mmHg) (mmHg) (mmHg) b 17 11 13 b1 16 11 13 c 17 11 12 d 15 10 12 f 15 10 9 g 10 5 — Moisture Vapor Transmission (MVT) rate was measured for sample a; in three states of stretch: relaxed, partial stretch and full stretch. The results are summarized in the following table showing a more stretched fabric transmits greater amounts of moisture. Sample a (70 denier weight in Transmission rate LYCRA ® in the weight grams after (grams per 24 hours construction) in grams 24 hours per square meter) a (relaxed) 217.58 214.83 869 a (partially 222.87 217.89 1573.68 stretched) a (fully) stretched) 221.56 215.37 1956.04 Example 2 In Part 1 of this example a castliner sample of the invention was constructed from a double ply of 70 denier 100 filament COOLMAX® polyester yarn (INVISTA™ North America Inc.) and 70 denier LYCRA® brand spandex single covered with 20 denier 7 filament nylon and then knitted and scoured; variations on this construction are noted in the following table. Those samples containing silver ion and a single sample treated with TINOSAN® antimicrobial (from Ciba Specialty Chemicals, Ardsley, N.Y., USA, 10502-2699) showed activity against the organisms tested: S. Aureus and Kleb. Pneumoniae. In Part 2 of this example a castliner sample of the invention was constructed from the materials noted in the table. Only the silver containing castliner was effective against any microbe tested. Apparently, the ZONYL®) 555 TEFLON®) treatment interferes with the antimicrobial action of the silver ion. However, this observation was not conclusive. % % Reduction Reduction of activity of activity Anti-microbial (Staph. (Kieb. Log10 kill Sample agent Test method Aureus) Pneumon.) rate comment Example 2, Part 1. FossFiber ™ Includes 15% ASTM 88.46 <1 staple fibers E2149 Xstatic ® Includes ASTM 99.96 3.397 Silver coated E2149 nylon yarn in each 4th feed Untreated ASTM — No control E2149 reduction treated TINOSAN ® AATCC100 54.4 97.93 <1 anti-microbial from Ciba Specialty Chemicals Example 2, Part 2. FossFiber ™ 48% ASTM — No and Zonyl ® FossFiber ™ E2149 reduction 555 48% TACTEL ® nylon, 4% LYCRA ® FossFiber ™ 48% ASTM 55. <1 FossFiber ™ E2149 48% TACTEL ® nylon, 4% LYCRA ® Untreated 48% ASTM — No control TACTEL ® E2149 reduction nylon, 24% cotton, 24% COOLMAX ® 4% LYCRA ® Untreated 96% ASTM — No control TACTEL ® E2149 reduction nylon, 4% LYCRA ®
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<SOH> BACKGROUND OF THE INVENTION <EOH>It is known to employ a cotton knit sock (e.g., single jersey knit) as a first layer and cotton or poly/cotton webbing for cushioning (also called padding) as a second layer under a hard shell casting material. Known casting materials are either of fiberglass or plaster-of-paris. In use, the known castliner comprises a cotton jersey sleeve, which is pulled over the limb being treated, and a cotton webbing wrapped around the limb. Typically, some skill is required for application of the castliner of this known type. Particular skill is needed during application of the layers of cotton webbing, which is cumbersome to apply. Especially important is the required thickness of cotton webbing which ultimately protects the limb during the cast removal process. A particular disadvantage of such known castliners is their poor water repellency and moisture transmission rate. Water retention by known castliners fosters the growth of bacteria causing patient complaints about: unpleasant odors, itching, and general discomfort. An improvement to the foregoing known cotton cast lining is described in U.S. Pat. No. 5,540,964 to Mallen. Mallen discloses a cast lining which is capable of transporting moisture from beneath the cast to the air space within the cast and ultimately to the outside area. In one embodiment of the Mallen invention a fabric is formed from a blend of hydrophobic synthetic fibers (e.g., polyester) and a second fiber (spandex). This fabric is constructed into a tube with or without open ends and used as castliner beneath an orthopedic cast. Mallen's cast lining tube is then made “hydrophilic” according to methods disclosed therein. In general, the Mallen fabric conforms closely to the limb being treated due to the elastic fiber content of the tubular cast lining. Mallen specifically discloses use of LYCRA® (branded spandex from INVISTA S.à r.l. of Wilmington, Del.) in its construction. Applicants have found various prior art cast lining materials disadvantageous in several modes of performance. First, jersey knit sleeve and cotton webbing can be difficult for unskilled casting room operators to apply uniformly. Second, the moisture absorption of these sleeve and webbing liners is high. Third, the sleeve and webbing lining can be stiff and can provide pressure points at joints especially. The Mallen (U.S. Pat. No. 5,540,964) cast lining is an improvement in conformance to the limb shape. It would be desirable to improve cushioning and moisture transmission rate while minimizing the pressure points caused by elastic yarns in the construction. Typically, points of increased pressure on the limb are present in areas of the limb joints and where the limb changes diameter most abruptly. Thus, a longstanding unmet need for a sleeve-like knitted castliner without the deficiencies of the prior art exists.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a castliner in the form of a three-dimensionally knitted tubing for use beneath an orthopedic cast with enhanced cushioning and comfortable conformance to the body. In addition, the sleeve-like knitted castliner of the present invention may provide enhanced moisture transmission rate, antimicrobial properties, and decreased water uptake. Moreover, the sleeve-like knitted castliner of the present invention may be easily and readily applied to limb or body portion in treatment by a relatively unskilled person. The present invention provides a sleeve-like knitted castliner for use beneath an orthopedic cast, comprising a micro-denier yarn. The invention further includes a castliner comprising a spandex yarn having a specified stress/strain curve defining the elastic modulus of the spandex yarn. A preferred castliner comprises a spandex yarn in an amount of about 2 to about 20 percent by weight of the total castliner. A preferred castliner comprises LYCRA® 902C or LYCRA® 906 brand spandex fiber available from INVISTA S.à r.l. of Wichita, Kans. and Wilmington, Del. The sleeve-like knitted castliner of the invention provides enhanced cushioning as compared to castliners of the prior art, and conforms tightly to the limb or body portion under treatment. Further in accordance with the present invention, there is provided a sleeve-like knitted castliner for use beneath an orthopedic cast, comprising an acrylic yarn treated with a phase change material. This castliner may also include a spandex yarn.
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20040628
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20060103
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20050203
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64810.0
| 0
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DOSTER GREENE, DINNATIA JO
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SLEEVE-LIKE KNITTED STRUCTURE FOR USE AS A CASTLINER
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,878,855
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ACCEPTED
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Federated identity brokering
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A method, system and apparatus for federated identity brokering. In accordance with the present invention, a credential processing gateway can be disposed between one or more logical services and one or more service requesting clients in a computer communications network. Acting as a proxy and a trusted authority to the logical services, the credential processing gateway can map the credentials of the service requesting clients to the certification requirements of the logical services. In this way, the credential processing gateway can act as a federated identity broker in providing identity certification services for a multitude of different service requesting clients without requiring the logical services to include a pre-configuration for specifically processing the credentials of particular service requesting clients.
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1. A federated identity brokering method comprising the steps of: intercepting a service request targeting a specific logical service; comparing a security credential associated with said service request to credential requirements specified by said specific logical service; modifying said security credential to comport with said credential requirements; and, routing said intercepted service request with said modified security credential to said specific logical service. 2. The method of claim 1, wherein said intercepting step comprises the steps of: retrieving an original service description for said specific logical service from a privately accessible registry; expanding said original service description to include broader credential requirements; changing a service address in said expanded service description for said specific logical service to specify a proxy to said specific logical service for performing said comparing, modifying and routing steps; and, publishing said expanded service description to a publicly accessible service registry. 3. The method of claim 1, wherein said comparing step comprises the step of comparing a digital signature applied to said service request with a list of digital signatures accepted by said specific logical service. 4. The method of claim 1, wherein said comparing step comprises the step of comparing an encryption scheme applied to said service request with a list of encryption schemes accepted by said specific logical service. 5. The method of claim 1, wherein said comparing step comprises the step of comparing an authorization associated with said service request with a list of authorizations required by said specific logical service. 6. The method of claim 3, wherein said modifying step comprises the steps of: validating an incoming digital signature with a certifying authority not trusted by said logical service; and, asserting a digital signature for said service request using a certifying authority which is trusted by said logical service. 7. A federated identity brokering system comprising: a gateway service/proxy configured for communicative coupling to a plurality of logical services and a plurality of service requestors; a private service description repository communicatively coupled to said gateway service/proxy and to said logical services and storing a plurality original endpoint service descriptions for said logical services, each of said original endpoint service descriptions indicating credential requirements for corresponding ones of said logical services; and, a public service description repository communicatively coupled to said service requestors and said gateway service/proxy and storing expanded versions of said original endpoint service descriptions for said logical services. 8. The system of claim 7, wherein said gateway service/proxy is disposed in a demilitarized zone, said logical services and said private service description repository are disposed in a private network domain, and wherein said public service description is exposed for access by said service requestors. 9. The system of claim 7, wherein said logical services are Web services. 10. The system of claim 7, wherein said credentials specify at least one of a security assertion, a digital signature, an encryption scheme, and a security authorization. 11. The system of claim 7, wherein said original endpoint service descriptions are formatted according to one of the Web services endpoint language (WSEL) and WS-Policy. 12. A machine readable storage having stored thereon a computer program for federated identity brokering, the computer program comprising a routine set of instructions which when executed by a machine cause the machine to perform the steps of: intercepting a service request targeting a specific logical service; comparing a security credential associated with said service request to credential requirements specified by said specific logical service; modifying said security credential to comport with said credential requirements; and, routing said intercepted service request with said modified security credential to said specific logical service. 13. The machine readable storage of claim 12, wherein said intercepting step comprises the steps of: retrieving an original service description for said specific logical service from a privately accessible registry; expanding said original service description to include broader credential requirements; changing a service address in said expanded service description for said specific logical service to specify a proxy to said specific logical service for performing said comparing, modifying and routing steps; and, publishing said expanded service description to a publicly accessible service registry. 14. The machine readable storage of claim 12, wherein said comparing step comprises the step of comparing a digital signature applied to said service request with a list of digital signatures accepted by said specific logical service. 15. The machine readable storage of claim 12, wherein said comparing step comprises the step of comparing an encryption scheme applied to said service request with a list of encryption schemes accepted by said specific logical service. 16. The machine readable storage of claim 12, wherein said comparing step comprises the step of comparing an authorization associated with said service request with a list of authorizations required by said specific logical service. 17. The machine readable storage of claim 14, wherein said modifying step comprises the steps of: validating an incoming digital signature with a certifying authority not trusted by said logical service; and, asserting a digital signature for said service request using a certifying authority which is trusted by said logical service.
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BACKGROUND OF THE INVENTION 1. Statement of the Technical Field The present invention relates to federated identity management, and more particularly to brokering federated identities in a computer communications network. 2. Description of the Related Art Logical services such as Web services represent the leading edge of distributed computing and are viewed as the foundation for developing a truly universal model for supporting the rapid development of component-based applications over the World Wide Web. Web services are known in the art to include a stack of emerging standards that describe a service-oriented, component-based application architecture. Specifically, Web services are loosely coupled, reusable software components that semantically encapsulate discrete functionality and are distributed and programmatically accessible over standard Internet protocols. Conceptually, Web services represent a model in which discrete tasks within processes are distributed widely throughout a value net. Notably, many industry experts consider the service-oriented Web services initiative to be the next evolutionary phase of the Internet. Typically, Web services can be defined by an interface such as the Web services definition language (WSDL), and can be implemented according to the interface, though the implementation details matter little so long as the implementation conforms to the Web services interface. Once a Web service has been implemented according to a corresponding interface, the implementation can be registered with a Web services registry, such as Universal Description, Discover and Integration (UDDI), as is well known in the art. Upon registration, the Web service can be accessed by a service requestor through the use of any supporting messaging protocol, including for example, the simple object access protocol (SOAP). Web services users typically can be known by multiple identities across multiple, secure, computing domains. In particular, each user can enjoy a unique identity within a particular secure domain which can differ from the identity enjoyed by the same user in a different secure domain. This multiplicity of identities for individual users can impede the ability of Web services in each secure domain to collaborate with one another in order to provide a higher level of function desirable to an end user or requesting process. Yet, it can be desirable to collaboratively arrange Web services in multiple secure domains so as to capitalize on the integration of information form the multiple different domains to form a cohesive application. The notion of a federated identity can require the exchanging of identity information in the form of security credentials between different secure domains to provide a level of collaboration necessary to arrange Web services into a cohesive coputing application. Presently, a wide variety of credential forms are known to be available including Kerberos, X.509, LTPA and the like. Notably, when accessing a single Web service provider, the credential format can be manageable problem. In contrast, handling with credential formats and their associated trust relationships can become an acute and complex problem when attempting to federate an arbitrarily large set of Web services providers. Generally, a canonical form of credentials can suffice as the sole solution to the problem of federated identities. Notwithstanding, the use of a canonical form of credentials can become unwieldy for large sets of providers. SUMMARY OF THE INVENTION The present invention addresses the deficiencies of the art in respect to the federation of identity in a computer communications network and provides a novel and non-obvious method, system and apparatus for the dynamic transformation of credential formats and for the exchange of credential information between computing processes in a computer communications network. Specifically, a gateway service/proxy can be disposed between a logical service and a requesting process. The gateway service/proxy can expand the service description of the logical service to include a broader security description. Consequently, the gateway service/proxy can accept and map a variety of credentials from requesting processes to the requirements of the logical service to validate the credentials of the requesting processes. A federated identity brokering method can include intercepting a service request targeting a specific logical service and comparing a security credential associated with the service request to credential requirements specified by the specific logical service. The security credential can be modified to comport with the credential requirements. Subsequently, the intercepted service request can be routed with the modified security credential to the specific logical service. The intercepting step can include retrieving an original service description for the specific logical service from a privately accessible registry and expanding the original service description to include broader credential requirements. Also, a service address in the expanded service description can be changed for the specific logical service to specify a proxy to the specific logical service for performing the comparing, modifying and routing steps. Finally, the expanded service description can be published to a publicly accessible service registry. Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. The embodiments illustrated herein are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein: FIG. 1 is a schematic illustration of a service delivery network configured for federated identity brokering in accordance with the present invention; FIG. 2 is a block diagram illustrating entity interactions in a federated identity brokering process in the network of FIG. 1; and, FIG. 3 is a flow chart illustrating a federated identity brokering process in the network of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a method, system and apparatus for federated identity brokering. In accordance with the present invention, a credential processing gateway can be disposed between one or more logical services and one or more service requesting clients in a computer communications network. Acting as a proxy and a trusted authority to the logical services, the credential processing gateway can map the credentials of the service requesting clients to the certification requirements of the logical services. In this way, the credential processing gateway can act as a federated identity broker in providing identity certification services for a multitude of different service requesting clients without requiring the logical services to include a pre-configuration for specifically processing the credentials of particular service requesting clients. In further illustration of the preferred embodiments of the present invention, FIG. 1 is a schematic illustration of a service delivery network configured for federated identity brokering in accordance with the present invention. Referring to FIG. 1, one or more service requesting clients 110 can be communicatively coupled to one or more logical services 130 over a data communications network 120. The service requesting clients 110 can include computing processes operating in host computing environments configured for network interoperability. The logical services 130, by comparison, can include distributed discoverable logical components, such as Web services, whose interface can be discovered through directory services such as UDDI. Each of the logical services 130 can be coupled to an internal service description repository 140A. The internal service description repository 140A can include a directory of service offerings for each of the logical services 130. Moreover, the internal service description repository 140A can include individual descriptions of the security assertion requirements each of the individual ones of the logical services 130 which are necessary for an external one of the service requesting clients 110 to access the individual ones of the logical services 130. In this regard, the individual descriptions can include an endpoint description of the security requirements and capabilities of the individual logical services 130, specified using extensions to WSDL, such as the Web services endpoint language (WSEL), WS-Policy, to name a few. Notably, access to the internal service description repository 140A can be limited through a private interface as would be expected where the internal service description repository 140A is disposed within a private Intranet. A credential processing gateway 160 having a certification authority process 150 also can be coupled to the internal service description repository 140A and further can be communicatively linked to the logical services 130. The credential processing gateway 160 can be configured to register subscribing ones of the services 130 and to perform federated identity brokering on behalf of subscribing ones of the services 130 for the service requesting clients 110. In this regard, an expanded service description repository 140B can be coupled to the credential processing gateway 160 and publicly exposed to the service requesting clients 110 over the data communications network 120. The expanded service description repository 140B can include expanded versions of the individual descriptions in the internal service description repository 140A. By expanded, it is meant that the service descriptions in the expanded service description repository 140B can include a wider selection of possible security assertions and credential formats which can be processed in the credential processing gateway 160 as compared to the credential processing capabilities of any of the logical services 130. The credential processing gateway 160, acting as a federated identity broker, can map the wider selection of possible security assertions and credential formats to the more narrow, acceptable set of credentials specified in the internal service description repository 140A for corresponding ones of the logical services 130. As a result, the individual logical services 130 need not require a canonicalized form of the security credentials of the service requesting clients 110. In more specific illustration, FIG. 2 is a block diagram depicting entity interactions in a federated identity brokering process in the network of FIG. 1. In the process of the present invention, a target service 240 can publish an endpoint service description to the service description repository 260 within an internal domain 290 such as an Intranet. Subsequently, the target service 240 can subscribe to the gateway service/proxy 230 in a demilitarized portion 280 of the network so that the gateway service proxy 230 can perform federated identity brokering on behalf of the target service 240. Notably, the gateway service/proxy 230 can be a trusted partner to the target service 240 as established by the trusted certifying authority 210. Upon receiving the subscription, the gateway service/proxy 230 can retrieve the endpoint service description from the service description repository 260 in the internal domain 290 and can expand the service description, posting the expanded form of the service description to a service description repository 250 in the demilitarized portion 280 of the network. In particular, the gateway service/proxy 230 can interpret the security and location properties of the service description in order to evaluate conversion capabilities. For instance, the gateway service/proxy 230 can expand the service description to include a broader set of allowable security interactions. Based upon the evaluation, a new endpoint and service description can be generated, including a new service address to reference the gateway service/proxy 230 in lieu of the target service 240. The service description repository 250 can be accessed by external entities in an external domain 270 as the service description repository 250 can be positioned within the demilitarized portion 280 of the network. A service requester 220 can access the service description repository 250 to located the target service 240. Responsive to the terms of the expanded form of the service description, the service requestor 220 can obtain credentials certified by a trusted certifying authority 210 in respect to the gateway service/proxy 230. The service requestor 220 in turn can submit the credentials to the gateway service/proxy 230 to establish the identity of the service requestor 220. Relying upon the knowledge of the trusted certifying authority 210, the gateway service/proxy 230 can map the requirements of the target service 240 with the certification provided by the service requestor 220. In particular, the gateway service/proxy 230 can validate the credentials through the operation of a trusted certifying authority 210, or internally where the gateway service/proxy 230 acts as a trusted certifying authority 210. If the service requestor 220 can be validated, the gateway service/proxy 230 can route a service request provided by the service requestor 220 to the target service 240, the gateway service/proxy 230 acting as a trusted party to the target service 240. In consequence, the target service 240 can process the request, returning a response to the gateway service/proxy 230 which in turn can route the response to the service requestor 220. FIG. 3 is a flow chart illustrating a preferred federated identity brokering process in the network of FIG. 1. Beginning block 310, an incoming service request can be evaluated with respect to the security content of the incoming service request. In this regard, in decision block 320 it can be determined whether the credential has been certified by an authority trusted by the target service. If not, in block 330 the credential can be separately validated against the originally specified certifying authority and a new credential can be generated by a certifying authority trusted by the target service in block 340. Regardless, the process can continue through to decision block 350. In decision block 350 the credentials specified in association with the request can be compared with a generated endpoint description for a target service specified in the service request to determine whether a conversion of the credentials will be required to comport with the required security of the target service. If so, in block 360 a modified form of the credentials can be generated to comport with the requirements of the target service. In either case, in block 370 a modified message can be composed based upon the incoming service request and the security credentials. Subsequently, in block 380 the target service can be invoked along with the modified message. Notably, a similar process can be repeated for handling a service response rather than a service request. The present invention can be realized in hardware, software, or a combination of hardware and software. An implementation of the method and system of the present invention can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system, or other apparatus adapted for carrying out the methods described herein, is suited to perform the functions described herein. A typical combination of hardware and software could be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which, when loaded in a computer system is able to carry out these methods. Computer program or application in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following a) conversion to another language, code or notation; b) reproduction in a different material form. Significantly, this invention can be embodied in other specific forms without departing from the spirit or essential attributes thereof, and accordingly, reference should be had to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Statement of the Technical Field The present invention relates to federated identity management, and more particularly to brokering federated identities in a computer communications network. 2. Description of the Related Art Logical services such as Web services represent the leading edge of distributed computing and are viewed as the foundation for developing a truly universal model for supporting the rapid development of component-based applications over the World Wide Web. Web services are known in the art to include a stack of emerging standards that describe a service-oriented, component-based application architecture. Specifically, Web services are loosely coupled, reusable software components that semantically encapsulate discrete functionality and are distributed and programmatically accessible over standard Internet protocols. Conceptually, Web services represent a model in which discrete tasks within processes are distributed widely throughout a value net. Notably, many industry experts consider the service-oriented Web services initiative to be the next evolutionary phase of the Internet. Typically, Web services can be defined by an interface such as the Web services definition language (WSDL), and can be implemented according to the interface, though the implementation details matter little so long as the implementation conforms to the Web services interface. Once a Web service has been implemented according to a corresponding interface, the implementation can be registered with a Web services registry, such as Universal Description, Discover and Integration (UDDI), as is well known in the art. Upon registration, the Web service can be accessed by a service requestor through the use of any supporting messaging protocol, including for example, the simple object access protocol (SOAP). Web services users typically can be known by multiple identities across multiple, secure, computing domains. In particular, each user can enjoy a unique identity within a particular secure domain which can differ from the identity enjoyed by the same user in a different secure domain. This multiplicity of identities for individual users can impede the ability of Web services in each secure domain to collaborate with one another in order to provide a higher level of function desirable to an end user or requesting process. Yet, it can be desirable to collaboratively arrange Web services in multiple secure domains so as to capitalize on the integration of information form the multiple different domains to form a cohesive application. The notion of a federated identity can require the exchanging of identity information in the form of security credentials between different secure domains to provide a level of collaboration necessary to arrange Web services into a cohesive coputing application. Presently, a wide variety of credential forms are known to be available including Kerberos, X.509, LTPA and the like. Notably, when accessing a single Web service provider, the credential format can be manageable problem. In contrast, handling with credential formats and their associated trust relationships can become an acute and complex problem when attempting to federate an arbitrarily large set of Web services providers. Generally, a canonical form of credentials can suffice as the sole solution to the problem of federated identities. Notwithstanding, the use of a canonical form of credentials can become unwieldy for large sets of providers.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention addresses the deficiencies of the art in respect to the federation of identity in a computer communications network and provides a novel and non-obvious method, system and apparatus for the dynamic transformation of credential formats and for the exchange of credential information between computing processes in a computer communications network. Specifically, a gateway service/proxy can be disposed between a logical service and a requesting process. The gateway service/proxy can expand the service description of the logical service to include a broader security description. Consequently, the gateway service/proxy can accept and map a variety of credentials from requesting processes to the requirements of the logical service to validate the credentials of the requesting processes. A federated identity brokering method can include intercepting a service request targeting a specific logical service and comparing a security credential associated with the service request to credential requirements specified by the specific logical service. The security credential can be modified to comport with the credential requirements. Subsequently, the intercepted service request can be routed with the modified security credential to the specific logical service. The intercepting step can include retrieving an original service description for the specific logical service from a privately accessible registry and expanding the original service description to include broader credential requirements. Also, a service address in the expanded service description can be changed for the specific logical service to specify a proxy to the specific logical service for performing the comparing, modifying and routing steps. Finally, the expanded service description can be published to a publicly accessible service registry. Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
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20040628
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20090825
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20060126
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80822.0
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H04L932
| 0
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PERUNGAVOOR, VENKATANARAY
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FEDERATED IDENTITY BROKERING
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UNDISCOUNTED
| 0
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ACCEPTED
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H04L
| 2,004
|
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10,878,883
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ACCEPTED
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Multi-modality diagnostic imager
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According to some embodiments, a multimodality diagnostic imaging system having one or more gamma cameras and a flat panel x-ray detector mounted on a common gantry to perform simultaneous FPCT and SPECT studies. In other embodiments, such systems may included EKG devices to gate said studies.
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1. A multimodality diagnostic imaging system, comprising: a gantry having a receiving aperture; at least one gamma ray detector mounted for rotation around the receiving aperture; an x-ray tube mounted for rotation around the receiving aperture; a flat panel x-ray detector mounted for rotation around the receiving aperture; wherein said diagnostic imaging system is operable to perform a computerized tomography scan and a single photon emission computerized tomography scan. 2. The system of claim 1, wherein the number of gamma cameras is one. 3. The system of claim 1, wherein the number of gamma cameras is two. 4. The system of claim 1, further comprising an electrocardiogram device, wherein said electrocardiogram device provides a signal to gate the SPECT and CT studies. 5. A method of performing multimodality scanning, comprising the steps of: providing a gantry; providing a flat panel x-ray detector on said gantry; performing a single photon emission computerized tomography study on a patient using the gantry; performing a computerized tomography study on a the patient using a flat panel x-ray detector. 6. A method of performing multimodality scanning, comprising the steps of providing a gantry having a receiving aperture; providing a flat panel x-ray detector mounted to rotate about the receiving aperture; providing a gamma ray detector mounted to rotate about the receiving aperture; acquiring data for a FPCT scan using said x-ray detector; rotating the flat panel x-ray detector about the aperture; and acquiring data for a SPECT study with said gamma camera; rotating the gamma camera about the aperture. 7. The method of claim 6, further comprising: blocking data acquisition by the flat panel x-ray detector while acquiring data with the gamma camera; and blocking data acquisition by the gamma camera while acquiring data with the flat panel x-ray detector.
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CROSS REFERENCE TO A RELATED APPLICATION This application claims benefit of priority under 35 U.S.C. section 119(e) of U.S. Provisional Application No. 60/483,567 filed Jun. 27, 2003 which is hereby incorporated by reference. BACKGROUND 1. Field of the Invention The present invention relates to, inter alia, diagnostic imaging systems, and, in particular to a diagnostic imaging system using multiple modalities. More particularly, some preferred embodiments of the invention relate to methods and apparatuses for the using of digital X-ray and gamma camera modalities in the same diagnostic imaging system. 2. Background Discussion Medial imaging systems are designed to operate in a number of imaging modalities. Examples of different modalities include simple planar x-ray, Computerized Tomography (CT), angiography, simple planar imaging by gamma ray cameras, Single Photon Emission Computerized Tomography (SPECT), Position Emission Tomography (PET), and others. The particular characteristics of each modality lend themselves to particular applications. Diagnostic imaging systems which use multiple imaging modalities have been and continue to be developed. These multimodality systems can yield synergistic advantages above and beyond just the advantages of each specific modality. For example, it is known in the art advantage is gained by combining SPECT and CT in a dual-modality system with each mode mounted on separate gantries with the patient supported and transported between them. Such a system allows for more accurate fusion of structural (anatomical) CT data and functional (disease) SPECT data due to decreased patient movement. Spatial image fusion of conventional CT with SPECT often are inaccurate due to patient motion during the long SPECT data acquisition period. Moreover, the lack of a common gantry increases error in the fusion of the structural (anatomical) and functional images. This problem is exacerbated by the use of traditional-style cylindrical CT detectors, with contributes to vibration and other motion, further degrading image fusion. Cylindrical CT detectors are used to perform spiral CT scans. Furthermore, such cylindrical CT detectors are bulky and expensive. A further problem is that as the CT data have to be taken either before or after the SPECT data are acquired, the conventional CT combined with SPECT cannot realize image registration in time domain, which limits the usefulness of the system in many motion related clinical studies. For example, in cardiac studies, image registration for image fusion is difficult due to the motion of the heart. Alternative x-ray detectors using solid state systems are available. Such solid states systems use semiconductors such as amorphous silicon. Other systems have been proposed which use overlapping layers to detect both emissive and transmitted radiation. However such overlapping layer systems have questionable sensitivity and resolution. There remains a need in the art for a system which takes advantage of the advantages of image fusion using a common gantry and detectors with common geometry, which can promote motion related clinical studies while avoiding the problems of a size and cost problems of a cylindrical CT detector. SUMMARY OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention can significantly improve upon existing methods and/or apparatuses. According to some embodiments of the invention, a multimodality diagnostic imaging system having one or more gamma cameras and a flat panel x-ray detector mounted on a common gantry to perform CT and SPECT studies. Preferably, such studies are performed with alternative frame acquisition between CT and SPECT. In other embodiments, such systems may included EKG devices to gate said studies. According to other embodiments of the present invention, a method performing a multimodality performing multimodality scanning including the steps of providing a gantry having a receiving aperture, providing a flat panel x-ray detector mounted to rotate about the receiving aperture and providing a gamma ray detector mounted to rotate about the receiving aperture. Further steps include acquiring data for a FPCT scan using said x-ray detector, rotating the flat panel x-ray detector about the aperture, acquiring data for a SPECT study with said gamma camera and rotating the gamma camera about the aperture. The above and/or other embodiments, aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims. BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the present invention, as well as further objects, features and advantages of the preferred embodiments will be more fully understood with reference to the following detailed description of the preferred embodiments, when taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a sectional view of a multimodality imaging system including one X-ray detector and one gamma ray detector, which may be employed in some embodiments of the present invention; FIG. 2 is a sectional view of a multimodality imaging system including one X-ray detector and two gamma ray detectors in a substantially parallel orientation, which may be employed in some embodiments of the present invention; FIG. 3 is a sectional view of a multimodality imaging system including one X-ray detector and two gamma ray detectors at variable angle, which may be employed in some embodiments of the present invention. FIG. 4 is sectional view of a multimodality imaging system including a bar X-ray detector-and one gamma ray detector, which may be employed in some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 depicts an embodiment of the present invention. Multimodality imaging system 2 showing a single head gamma camera configuration. Such a system is composed of a common gantry 4. A patient 5 will be laid on a table 7. A gamma ray detector 6 and a flat panel digital X-ray detector (FPDXD) 8 are mounted to the gantry to rotate around the axis of the gantry. X-ray tube 10 is always opposite the PPDXD 8. In another embodiment, FPDXD 8 and x-ray tube 10 are at a fixed angle from each other. In another embodiment, they may be at a variable angle from each other. FIG. 2 shows another embodiment of the present invention. Please note that like numbers indicate like elements. Multimodality imaging system 11 shows a parallel dual head gamma camera configuration. Such a system is includes a common gantry 12. A first gamma ray detector 14 and a second gamma ray detector 16 are mounted to gantry 12 such that they may rotate about the axis of the gantry. Also on the common gantry 12 is a flat panel digital X-ray detector (FPDXD) 18. X-ray tube 20 is always opposite the FPDXD 8. In one embodiment, FPDXD 8 and gamma camera 10 are at a fixed angle from each other. In another embodiment, they may be at a variable angle from each other. FIG. 3 shows yet another embodiment of the present invention similar to FIG. 2. However, multimodality imaging system 22 is shown with gamma cameras 14 and 16 at a variable angle. All other elements are similar to the embodiment of FIG. 2. The gamma ray detectors, FPDXD and x-ray tubes described are mounted to the gantry above FIG. 4 shows yet another embodiment of the present invention. The multimodality imaging system 24 is shown with a common gantry 26. A single gamma camera 28 and a single bar X-ray detector 30 are both mounted on the gantry 26. X-ray tube 32 is opposite bar X-ray detector 30. The multimodality systems shown in the above embodiments are capable of many modes of operation. The FPXPD is capable of performing simple planar X-rays, at a potentially high resolution. If the FPDXD system is rotated about the patient axis, it capable of performing a CT scan, thus making it Flat Panel Computerized tomography system, or FPCT system. Further, such a system is capable of taking planner gamma camera images. Further, such a system is capable of performing SPECT studies. In isolation, performing the above functions is well known to those skilled in the art. However, the various embodiments are capable of performing simultaneous SPECT-FPCT studies on a common gantry. Such studies not only yield the advantages of image fusion seen in conventional CT-SPECT studies, but also extend the fusion to the time domain and therefore, realize the CT-SPECT image fusion to the 4th, or temporal, dimension. Performing a SPECT scan using gamma cameras involves acquiring data with the gamma camera, advancing the camera by an angle of rotation, acquiring another set of data, repeated, until enough data has been acquired to build a tomographic image. The has been termed a step and shoot technique. In contrast, a spiral CT acquisition of a single slice will take one the order of one second and involve continuous rotation of the CT scanner. This difference in operation makes the registration of tomographic images difficult in the temporal domain difficult. However, an FPCT also operates in a step and shoot method, and its shoot (data acquisition) period is of the same order of magnitude as the gamma camera. Thus, it is possible to interleave data acquisitions by the two modalities. This allows for the potential of registration of tomographic images in the temporal domain. In addition, the present invention provides multi modalities with the size and cost advantages of using a flat panel x-ray detector. Further, the use of a common gantry reduces movement and vibration, those further increasing the potential quality of image fusion. Preferably, the two scans are done with alternative frame acquisition between CT and SPECT, further reducing patient movement between the two scans. With alternative frame acquisition between CT and SPECT refers to the scan modes at which CT and SPECT data are acquired at an interleaved fashion following a certain patterns. Yet another embodiment of the present invention uses an EKG signal from the patient being studied to “gate” the SPECT and FPCT studies. This allows data acquisition form both studies to occur only at the same point in the cardiac cycle. Yet another embodiment is the use of FPCT data to detect cardiac motion and thus act as a gate for both FPCT (itself) and SPECT studies. While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein.
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<SOH> BACKGROUND <EOH>1. Field of the Invention The present invention relates to, inter alia, diagnostic imaging systems, and, in particular to a diagnostic imaging system using multiple modalities. More particularly, some preferred embodiments of the invention relate to methods and apparatuses for the using of digital X-ray and gamma camera modalities in the same diagnostic imaging system. 2. Background Discussion Medial imaging systems are designed to operate in a number of imaging modalities. Examples of different modalities include simple planar x-ray, Computerized Tomography (CT), angiography, simple planar imaging by gamma ray cameras, Single Photon Emission Computerized Tomography (SPECT), Position Emission Tomography (PET), and others. The particular characteristics of each modality lend themselves to particular applications. Diagnostic imaging systems which use multiple imaging modalities have been and continue to be developed. These multimodality systems can yield synergistic advantages above and beyond just the advantages of each specific modality. For example, it is known in the art advantage is gained by combining SPECT and CT in a dual-modality system with each mode mounted on separate gantries with the patient supported and transported between them. Such a system allows for more accurate fusion of structural (anatomical) CT data and functional (disease) SPECT data due to decreased patient movement. Spatial image fusion of conventional CT with SPECT often are inaccurate due to patient motion during the long SPECT data acquisition period. Moreover, the lack of a common gantry increases error in the fusion of the structural (anatomical) and functional images. This problem is exacerbated by the use of traditional-style cylindrical CT detectors, with contributes to vibration and other motion, further degrading image fusion. Cylindrical CT detectors are used to perform spiral CT scans. Furthermore, such cylindrical CT detectors are bulky and expensive. A further problem is that as the CT data have to be taken either before or after the SPECT data are acquired, the conventional CT combined with SPECT cannot realize image registration in time domain, which limits the usefulness of the system in many motion related clinical studies. For example, in cardiac studies, image registration for image fusion is difficult due to the motion of the heart. Alternative x-ray detectors using solid state systems are available. Such solid states systems use semiconductors such as amorphous silicon. Other systems have been proposed which use overlapping layers to detect both emissive and transmitted radiation. However such overlapping layer systems have questionable sensitivity and resolution. There remains a need in the art for a system which takes advantage of the advantages of image fusion using a common gantry and detectors with common geometry, which can promote motion related clinical studies while avoiding the problems of a size and cost problems of a cylindrical CT detector.
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<SOH> SUMMARY OF THE PREFERRED EMBODIMENTS <EOH>The preferred embodiments of the present invention can significantly improve upon existing methods and/or apparatuses. According to some embodiments of the invention, a multimodality diagnostic imaging system having one or more gamma cameras and a flat panel x-ray detector mounted on a common gantry to perform CT and SPECT studies. Preferably, such studies are performed with alternative frame acquisition between CT and SPECT. In other embodiments, such systems may included EKG devices to gate said studies. According to other embodiments of the present invention, a method performing a multimodality performing multimodality scanning including the steps of providing a gantry having a receiving aperture, providing a flat panel x-ray detector mounted to rotate about the receiving aperture and providing a gamma ray detector mounted to rotate about the receiving aperture. Further steps include acquiring data for a FPCT scan using said x-ray detector, rotating the flat panel x-ray detector about the aperture, acquiring data for a SPECT study with said gamma camera and rotating the gamma camera about the aperture. The above and/or other embodiments, aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims.
|
20040628
|
20060711
|
20050203
|
75457.0
| 0
|
TANINGCO, MARCUS H
|
MULTI-MODALITY DIAGNOSTIC IMAGER
|
UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,879,099
|
ACCEPTED
|
Toggle-lever clamping device for clamping work pieces with self-compensation
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A toggle-lever clamping device for clamping work pieces includes a box-shaped body which supports a clamping member movable between a forward disengaging position and a backward position for clamping the work piece. The device also includes control elements operatively connected to the clamping member by elements of an intermediate toggle-lever connecting link, and an articulated quadrilateral system; the intermediate connecting link is in the form of an axially yieldable flat spring having a plurality of side by side arranged elastically yieldable spring sections, aligned according to its longitudinal axis. The articulated quadrilateral system and the intermediate connecting link are constructed and disposed in such a way as to maintain an irreversible locking condition of the clamping member to clamp work pieces, compensating differences in thickness of the work pieces.
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1. Toggle-lever clamping device for clamping work pieces, of the type comprising: a box-shaped body having a longitudinal axis; at least one hook-shaped clamping member which partially protrudes from an elongated aperture at a fore end of said box-shaped body, said clamping member being movably supported between a forward disengaging position and a backward clamping position in which it locks a work piece; control means being provided for controlling the clamping member, said control means being operatively connected to the clamping member by an intermediate toggle-lever connecting link, having a longitudinal axis, and an articulated quadrilateral system, said intermediate toggle-lever connecting link having a dead center position, corresponding to a condition of irreversibility of the clamping member movement in its backward clamping position, characterised in that the intermediate toggle-lever connecting link is in the form of an axially yielding flat spring, said flat spring comprising a plurality of side by side arranged elastically yieldable spring sections; and in that the articulated quadrilateral system and the intermediate toggle-lever connecting link are constructed and disposed in such a way as to maintain an irreversible clamping condition of the clamping member to lock the work piece, compensating differences in thickness of the work pieces by means of a corresponding elastic yielding of the intermediate connecting link. 2. Toggle-lever clamping device for work pieces according to claim 1, in which the articulated quadrilateral system comprises a first crank member having a lever arm hinged to the toggle-lever connecting link, and a second crank member, said first and second crank members being pivotally supported by to the box-shaped body and hinged to the clamping member, at axially spaced apart points, characterised in that the toggle-lever connecting link, in the direction of the longitudinal axis of the box-shaped body, is disposed between the articulated quadrilateral system and the thrust member of the control means; and in that the toggle-lever connecting link is connected to the thrust member, respectively to the lever arm of the first crank member by hinge pins, said hinge pins being disposed on opposing sides of the thrust member in the backward position of the clamping member. 3. Toggle-lever clamping device for work pieces according to claim 2, characterised in that the first crank member of the articulated quadrilateral system has a length greater than the second crank member. 4. Toggle-lever clamping device for work pieces according to claim 3, characterised in that the ratio between the length of the first crank member and the length of the second crank member of the articulated quadrilateral system is comprised between 1.5 to 2.5. 5. Toggle-lever clamping device for work pieces according to claim 2, characterised in that the first crank member of the articulated quadrilateral system has a length greater than the lever arm of said crank member. 6. Toggle-lever clamping device for work pieces according to claim 5, characterised in that the ratio between the length of the first crank member of the articulated quadrilateral system and the length of its lever arm is comprised between 2 to 3. 7. Toggle-lever clamping device for work pieces according to claim 2, characterised in that the lever arm of the first crank member and the first crank member itself form an angle ranging between 90° to 120°. 8. Toggle-lever clamping device for work pieces according to claim 1, characterised in that each elastically yielding spring section of the intermediate toggle-lever connecting link comprises a shaped annular element having opposite internal stop surfaces, the different elastically yielding spring sections being side by side arranged, and being connected to one another along the longitudinal axis of the connecting link. 9. Toggle-lever clamping device for work pieces according to claim 8, characterised in that each elastically yielding spring section of the intermediate toggle-lever connecting link comprises a figure-of-eight shaped annular element, having opposite internal arch shaped stop surfaces. 10. Toggle-lever clamping device for work pieces according to claim 1, characterised by comprising additional limiting means for limiting the yielding in the axial direction of the toggle connecting link. 11. Toggle-lever clamping device for work pieces according to claim 11, characterised in that said additional limiting means comprise at least one limiting plate connected to the hinge pins of the toggle-lever connecting link by a first and a second through holes, at least one of said first and second through holes being in the form of slot extending in the axial direction of the connecting link.
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BACKGROUND OF THE INVENTION This invention concerns a toggle-lever clamping device for clamping work pieces, used in particular for underbody tightening and/or centering sheet metal parts in the manufacturing of motor vehicles, or for other similar uses. STATE OF THE ART In general, toggle-lever clamping devices are known, which are normally used for tightening and/or centering work pieces, along edges or through appropriate holes of the same work pieces, locking them against a shoulder surface of the same device, or against supporting structure. A clamping device of the aforementioned kind is for example described in DE 39 36 396. The device comprises a box-shaped body having a longitudinal axis, and a hook-shaped clamping member protruding from an elongated aperture at a fore end of the box-shaped body; the clamping member is supported by the box-shaped body to perform a movement in a longitudinal and cross direction, between a forward disengaging position and a backward clamping position in which it locks the work piece. The clamping device is also provided with control means for the clamping member, which comprises a thrust member sliding parallel to the longitudinal axis of the box-shaped body, an intermediate toggle-lever connecting link and an articulated quadrilateral system. The articulated quadrilateral system in turn comprises a first and second crank members spaced apart in the direction of the longitudinal axis of the box-shaped body, which are pivotally supported to rotate on a respective pivotal axes; the crank members are in turn connected to the clamping member by means of respective hinge pins. One of the crank members, in particular the crank member close to the fore end of the box-shaped body, is provided with a lever arm articulated to the toggle-lever connecting link. A clamping device of this kind however has the drawback that whenever it is required to lock work pieces of different thickness, an operator must necessarily adjust the position of the device with respect to the work piece to be locked, and/or provide a shoulder and/or supporting surface for the work pieces having a suitable disposition for clamping the work pieces, in relation to their thickness. This involves considerable consumption of time and costs due to the need to stop the production lines in order to carry out the necessary setting operations. For the purposes of this description, the expression “different thickness” is understood to mean that the differences in thickness of the work pieces are in the range of millimetres. OBJECTS OF THE INVENTION An object of this invention is to provide a clamping device for work pieces, of the aforementioned kind, which is structurally simple, highly reliable, and which can clamp work pieces of different thickness without the need for adjustments and/or settings by an operator, by automatically compensating the differences in thickness of the work pieces. Another object of this invention is to provide a clamping device of the aforementioned kind, which can be optionally used as a conventional clamping device, in which the internal stresses are limited, and the slack between inner mechanical is automatically taken up. BRIEF DESCRIPTION OF THE INVENTION The above can be achieved by means of a toggle-lever clamping device for clamping work pieces, of the type comprising: a box-shaped body having a longitudinal axis; at least one hook-shaped movable clamping member which partially protrudes from an elongated aperture at a fore end of said box-shaped body, said clamping member being movably supported between a forward disengaging position and a backward clamping position in which it locks a work piece; control means being provided for controlling the clamping member, said control means being operatively connected to the clamping member by an intermediate toggle-lever connecting link, having a longitudinal axis, and an articulated quadrilateral system, said intermediate toggle-lever connecting link having a dead center position, which corresponds to a condition of irreversibility of the clamping member movement in its backward clamping position, characterised in that the intermediate toggle-lever connecting link is in the form of an axially yielding flat spring, said flat spring comprising a plurality of side by side arranged elastically yieldable spring sections; and in that the articulated quadrilateral system and the intermediate toggle-lever connecting link are constructed and disposed in such a way as to maintain an irreversible clamping condition of the clamping member to lock the work piece, compensating differences in thickness of the work pieces by means of a corresponding elastic yielding of the intermediate connecting link. BRIEF DESCRIPTION OF THE DRAWINGS These and further features of the clamping device according to this invention, will be more clearly evident from the following description with reference to the accompanying drawings, in which: FIG. 1 shows a longitudinal sectional view of a clamping device for clamping work pieces according to the invention, with the clamping member is in a backward position in which it clamps a work piece; FIG. 2 shows a longitudinal sectional view of the clamping device for clamping work pieces of FIG. 1, with the clamping member in a forward disengaging position in which it releases a work piece; FIGS. 3, 4 and 5 show an intermediate toggle-lever connecting link of the clamping device, in three different axially deformed conditions; FIG. 6 shows an enlarged detail of the connecting link of the device, according to another embodiment; FIG. 7 shows a longitudinal section of the toggle-lever connecting link of FIG. 6, according to line 7-7. DETAILED DESCRIPTION OF THE INVENTION The general features of this invention will be illustrated hereunder by means of some embodiments. The toggle-lever clamping device for clamping work pieces according to the invention, shown in the FIGS. 1 to 5, comprises a box-shaped body 10 having a longitudinal axis, which supports at least one movable clamping member 11, in this case one. The clamping member 11 comprises a hook-shaped fore portion 11A which partially protrudes from an elongated aperture 10′ at a fore end of the box-shaped casing 10, and a rear portion or shank 11B supported by the box-shaped body 10 to perform a longitudinal movement and a cross movement, between a forward disengaging position and a backward clamping position in which it clamps a work piece P against a shoulder, for example a supporting plate 12 secured to the fore end of the box-shaped body 10. The clamping member 11, by its rear shank 11B, is operatively connected to control means capable of imparting the aforesaid movement to the clamping member 11. The clamping device can be provided with a hollow centering stem 13, defining a longitudinal centering axis for the work pieces, which can be secured to the fore end of the box-shaped body 10, for example by means of the supporting plate 12. The centering stem 13 is provided with a cavity for housing the hook-shaped portion 11A of the clamping member 11 in its forward position, as shown in FIG. 2, and a side slit from which the clamping member protrudes in its backward position to clamp the work piece, as shown in FIG. 1. The device also comprises control means operatively connected to the clamping member 11 in turn comprising for example a pneumatic or electric linear actuator 15, having a rod 16 operatively connected to a thrust member 14, sliding parallel to the longitudinal axis of the box-shaped body 10. As an alternative, the control means can comprise a manual control lever, not shown, operatively connected to the clamping member 11. Preferentially, the sliding axis of the thrust member 14, the longitudinal axis of the box-shaped body 10 and the aforesaid centering axis are parallely arranged and substantially close to each other, so as to have the smallest possible dimensions in the cross movement direction of the clamping member 11. The thrust member 14 on one side is provided with a fork shaped extension member 14′, to which is connected, by means of a hinge pin 17, an intermediate toggle-lever connecting link 18 having a longitudinal axis, which is of the axially controlled elastically yielding type; the hinge pin 17 for connecting the toggle link 18 to the fork shaped extension 14′ of the thrust member 14, is thus spaced apart on a side of the sliding axis of the thrust member 14. The intermediate connecting link 18 is in turn connected, by means of a hinge pin 19, to a lever arm 20′ of a first crank member 20 of an articulated quadrilateral system, which supports the clamping member 11 and operatively connects it to the control means. The connecting link 18 and the lever arm 20′ form a toggle-lever mechanism which has a per se known dead center position, which corresponds with a condition of irreversibility of the clamping member movement 11 in its backward position in which it clamps the work piece. The articulated quadrilateral system comprises the aforesaid first crank member 20, disposed close to the thrust member 14, which is supported by the box-shaped body 10 to rotate according to a first pivotal axis 21; the crank member 20 is connected to the clamping member 11 by means of a first hinge axis 22. The lever arm 20′ of the first crank member 20 is disposed at an angle with respect to the same crank member 20, and faces towards the thrust member 14. Preferentially, the arm 20′ of the first crank member 20 and the first crank member 20 itself form an angle ranging from 90° to 120°. The articulated quadrilateral system also comprises a second crank member 23, disposed towards the fore end of the box-shaped body 10, which is supported by the same box-shaped body 10 to rotate according to a second pivotal axis 24; the second crank member 23 is connected to the clamping member 11 by means of a second hinge axis 25. The intermediate toggle-lever connecting link 18 is in the form of an axially yielding flat spring, preferentially consisting of a pack of flat springs, comprising a plurality of side by side arranged elastically yieldable spring sections, aligned according to the longitudinal axis of the connecting link 18. A constructional structure of this kind allows the connecting link 18 to undergo considerable axial elastic deformation, at the same time achieving high reaction forces to the deformation of the connecting link 18 itself, which enable the clamping member 11 to exert high clamping forces on the work pieces. Thanks to its high controlled elastic yielding capacity, the toggle-lever connecting link 18 consequently allows to automatically compensate any differences in thickness of the work pieces, up to differences in thickness in the range of some millimetres; moreover, the articulated quadrilateral system 20,23,11B and the intermediate connecting link 18 are shaped and disposed in such a way as to maintain the irreversible locking condition of the clamping member to lock work pieces, once the toggle-lever mechanism has gone slightly beyond its dead center position. Each elastically yielding spring section of the intermediate toggle-lever connecting link 18 preferably comprises an annular shaped element 18′ with opposite internal stop surfaces 18″; the different elastically yielding spring sections are side by side arranged and are connected to one another along the axis of the connecting link 18 itself. Preferentially, the elastically yielding spring sections of the intermediate connecting link 18 comprise annular elements 18′ shaped in a figure-of-eight, each having opposite arch shaped internal stop surfaces 18″. In the FIGS. 3 to 5, the intermediate connecting link 18 is shown in three different conditions of axial deformation, in relation to the thickness of the work pieces P, which are clamped. In particular, FIG. 3 shows the connecting link 18 in the case in which a work piece of limited thickness is clamped; in such case, the connecting link 18 is in a slightly axially deformed condition, with the opposite stop surfaces 18″ spaced apart from each other by a space d1. FIG. 4 shows the connecting link 18 in the case in which a work piece of greater thickness is clamped; in such case, the connecting link 18 is in a more axially deformed condition, with the opposite stop surfaces 18″ spaced apart from each other by a distance d2 shorter than d1. Lastly, FIG. 5.shows the connecting link 18 in the case in which a work piece of the maximum thickness permitted by the device is clamped; in such case, the connecting link 18 is in a totally axially deformed condition, with the opposite stop surfaces 18″ in contact with each other, at a space d3 equivalent to zero. The toggle-lever connecting link 18, in the direction of the longitudinal axis of the box-shaped body 10, is disposed between the articulated quadrilateral system and the thrust member 14 of the control means; such disposition of the connecting link results in a considerable reduction of the dimensions of the device in the direction of the cross movement of the clamping member 11, achieving a considerable improvement in the possibilities of handling the work pieces and the tools necessary for the various operations close to the clamping device. Moreover, the hinge pins 17 and 19 of the toggle-lever connecting link 18, respectively with the thrust member 14 and with the arm 20′ of the first crank member 20, are disposed on opposite sides of the thrust member 14 in the backward position of the clamping member 11. The first crank member 20 of the articulated quadrilateral system has a length greater than the second crank member 23 of the same system; preferentially, the ratio between the length of the first crank member 20 and that of the second crank member 23 of the articulated quadrilateral system is comprised between 1.5 to 2.5. The first crank member 20 of the articulated quadrilateral system is also of a greater length than the lever arm 20′ of the same crank member 20; in particular, the ratio between the length of the first crank member 20 of the articulated quadrilateral system and that of its lever arm 20′ is comprised for example between 2 to 3. The clamping device also comprises scraping and cleaning means capable of preventing the penetration of dirt through the elongated aperture at the fore end of the box-shaped body 10; the cleaning means in turn comprise a closing plate 26, housed in an appropriate seat at the fore end of the box-shaped body 10, and a movable scraping member 27, which have respective cross scraping edges which slide in contact with corresponding shaped side surfaces of the clamping member 11 during its movement. As illustrated in FIGS. 6 and 7, the clamping device of the invention can further comprise additional limiting means for limiting the yielding of the toggle connecting link 18 in the axial direction. Such an additional limiting means preferentially comprise at least one limiting plate 30 connected to the hinge pins 17, 19 of the toggle-lever connecting link 18 respectively by a first and a second through holes 31, 32 at the ends of the limiting plate 30; in this case, the device comprises a first and a second limiting plate 30, parallely arranged on opposite sides of the flat spring of the connecting link 18. In order to allow a controlled axial yielding movement of the toggle-lever connecting link 18, at least one of said first and second through holes 31 and 32 is in the form of a slot extending in the axial direction of the connecting link axis, as illustrated in FIGS. 6 and 7, in which only the hole 31 is in the form of a slot. Therefore, it is possible to modify the operation of the device, as regards the axial yielding of the connecting link 18, by simply providing the same device with limiting plates 30 having a slot or hole 31 of different axial dimensions. In this way, the clamping device can be used according to different manners, in relation to the clamping requirements of the work pieces in the production lines. In particular, according to a first use, the device is not provided with the limiting plates 30 for the connecting link yielding, thus allowing a complete axial yielding of the same toggle-lever connecting link 18, in such a way to automatically compensate great differences in the work piece thickness, up to some millimetres. According to a second use, the device is provided with the limiting plates 30 for the connecting link each having a respective slot or hole 31, thus allowing a predetermined axial yielding movement of the toggle-lever connecting link 18; in such a way it is allowed a more limited compensation of the work piece thickness and/or an axial preloading of the connecting link 18, while evidencing possible work piece thickness differences when the clamping member 11 doesn't reach a correct clamping position. According to a third use, the device is provided with limiting plates 30 for the connecting link yielding, having slots or through holes 31 of greater length, thus allowing to the connecting link 18 of the device to assume a nearly rigid configuration in order to define an exact clamping geometry, while compensating also internal clearances of the device. In the second and third cases, the flat spring of the connecting link 18 can have a limited thickness, since the axial thrust in these cases is exerted by the limiting plates 30, so it is not necessary to have a flat spring of full thickness dimensions. What has been described and shown with reference to the accompany drawings has been given purely by way of example in order to illustrate the general features of the invention, and of several of its preferential embodiments; consequently, other modifications and variations to the toggle-lever clamping device for clamping work pieces are possible, without thereby deviating from the scope of the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>This invention concerns a toggle-lever clamping device for clamping work pieces, used in particular for underbody tightening and/or centering sheet metal parts in the manufacturing of motor vehicles, or for other similar uses.
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<SOH> BRIEF DESCRIPTION OF THE INVENTION <EOH>The above can be achieved by means of a toggle-lever clamping device for clamping work pieces, of the type comprising: a box-shaped body having a longitudinal axis; at least one hook-shaped movable clamping member which partially protrudes from an elongated aperture at a fore end of said box-shaped body, said clamping member being movably supported between a forward disengaging position and a backward clamping position in which it locks a work piece; control means being provided for controlling the clamping member, said control means being operatively connected to the clamping member by an intermediate toggle-lever connecting link, having a longitudinal axis, and an articulated quadrilateral system, said intermediate toggle-lever connecting link having a dead center position, which corresponds to a condition of irreversibility of the clamping member movement in its backward clamping position, characterised in that the intermediate toggle-lever connecting link is in the form of an axially yielding flat spring, said flat spring comprising a plurality of side by side arranged elastically yieldable spring sections; and in that the articulated quadrilateral system and the intermediate toggle-lever connecting link are constructed and disposed in such a way as to maintain an irreversible clamping condition of the clamping member to lock the work piece, compensating differences in thickness of the work pieces by means of a corresponding elastic yielding of the intermediate connecting link.
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20040630
|
20051220
|
20050127
|
63405.0
| 0
|
WILSON, LEE D
|
TOGGLE-LEVER CLAMPING DEVICE FOR CLAMPING WORK PIECES WITH SELF-COMPENSATION
|
SMALL
| 0
|
ACCEPTED
| 2,004
|
|||
10,879,133
|
ACCEPTED
|
Method for forming conductive line of semiconductor device
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A method for conductive line of semiconductor device is disclosed. A cobalt silicide layer is formed on an impurity junction region exposed through a contact hole. The cobalt silicide layer stabilizes a contact resistance so that the contact resistance of the impurity junction region does not vary in subsequent thermal processes.
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1. A method for forming conductive line of semiconductor device, comprising the steps of: forming a lower insulating film on a semiconductor substrate including a gate electrode and an impurity junction region; etching the lower insulating film to form a first contact hole exposing a top surface of the gate electrode and a second contact hole exposing the impurity junction region; forming a cobalt silicide layer on the impurity junction region exposed through the second contact hole; forming a stacked structure of a Ti film and a TiN film on the semiconductor substrate including the first and the second contact holes; forming a conductive layer on the lower insulating film including the first and the second contact holes; and patterning the conductive layer to form a conductive line pattern. 2. The method according to claim 1, wherein the step of forming the cobalt silicide layer comprises: forming a cobalt film on the semiconductor substrate including the first and the second contact holes; performing a rapid thermal process to react the cobalt film with a surface of the impurity junction region; and removing an unreacted portion of the cobalt film. 3. The method according to claim 2, wherein the cobalt film is formed by a PVD method and has a thickness ranging from 50 to 150 Å. 4. The method according to claim 2, wherein the rapid thermal process comprises: a first rapid thermal process performed at a temperature ranging from 650 to 750° C. for 10 to 30 seconds; and a second rapid thermal process performed at a temperature ranging from 800 to 880° C. for 10 to 30 seconds. 5. The method according to claim 2, wherein the unreacted portion of the cobalt film is removed using SC-1 solution. 6. The method according to claim 1, wherein the step of forming a stacked structure of a Ti film and a TiN film comprises: forming the Ti film having a thickness ranging from 100 to 200 Å via a first PVD process; and forming the TiN film having a thickness ranging from 100 to 400 Å via a second PVD process. 7. The method according to claim 1, wherein the conductive line pattern is a bit line pattern or a metal wiring.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to method for forming conductive line of semiconductor device, and in particular to an improved method for forming conductive line of semiconductor device which provides improved contact resistance characteristics. 2. Description of the Background Art A bit line structure, which is a data I/O path of semiconductor device, comprises a polycide structure consisting of a polysilicon layer and a tungsten silicide layer. In case of a highly integrated and high-speed semiconductor device, a tungsten bit line having low resistance is used instead since this structure has a limitation due to high sheet resistance. Resistance stabilization is required for the tungsten bit lone because the contact resistance varies by the subsequent thermal processes. Generally, the contact resistance is greatly increased during a subsequent thermal process in a P+ region where a thick Ti film is formed due to loss of dopants in a source/drain region. Therefore, a bit line comprising a relatively thin Ti film is used. However, although the thin Ti film stabilizes the contact resistance of P+ region, contact resistances of N+ region and tungsten silicide layer of gate electrode are largely increased. Therefore, the thickness of the Ti film is adjusted so that the contact resistances of P+ region and N+ region and gate region have moderate values. However, as the contact area becomes smaller, the contact resistance, especially the contact resistance of gate electrode, is drastically increased as illustrated in FIG. 1. The thickness of the Ti film must be increased to reduce the contact resistance. However, increase in the thickness of the Ti film increase the contact resistance of P+ region as described above, resulting in a degradation of device characteristic. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide method for forming conductive line of semiconductor device wherein a cobalt silicide layer is formed on a surface of a source/drain region to stabilize contact characteristics and improve reliability of the device. In order to achieve the above-described object of the invention, there is provided a method for forming conductive line of semiconductor device, comprising: forming a lower insulating film on a semiconductor substrate including a gate electrode and an impurity junction region; etching the lower insulating film to form a first contact hole exposing a top surface of the gate electrode and a second contact hole exposing the impurity junction region; forming a cobalt silicide layer on the impurity junction region exposed through the second contact hole; forming a stacked structure of a Ti film and a TiN film on the semiconductor substrate including the first and the second contact holes; forming a conductive layer on the lower insulating film including the first and the second contact holes; and patterning the conductive layer to form a conductive line pattern. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein: FIG. 1 is a graph illustrating variation of contact resistance according to variation of contact area. FIGS. 2A through 2D are cross-sectional diagrams illustrating method for forming conductive line of semiconductor device in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming conductive line of semiconductor device in accordance with a preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. FIGS. 2A through 2D are cross-sectional diagrams illustrating method for forming conductive line of semiconductor device in accordance with the present invention. Referring to FIG. 2A, a device isolation film (not shown) for defining an active region is formed on a semiconductor substrate 11. Thereafter, a stacked structure of a gate oxide film 15, a polysilicon film 17 for gate electrode, a tungsten silicide layer 19 and a hard mask film 21 is formed on the semiconductor substrate 11. The stacked structure is then etched to form a gate electrode. Next, an n-type or a p-type impurity is ion-implanted in the semiconductor substrate 11 using the gate electrode as an implant mask to form an impurity junction region 13. Thereafter, an insulating film (not shown) is formed on the semiconductor substrate 11 and then anisotropically etched to form an insulating film spacer 23 at a sidewall of the gate electrode. Next, a lower insulating film 25 planarizing the entire surface is formed on a semiconductor substrate 11. The lower insulating film 25 and the hard mask film 21 are selectively etched to form a first contact hole 27 exposing the tungsten silicide layer 19 and a second contact hole 29 exposing the impurity junction region 13. Natural oxide films at the bottoms of the first contact hole 27 and the second contact hole 29 may be removed. Thereafter, a cobalt film 31 is formed on the semiconductor substrate 11 including the first and the second contact holes 27 and 29. Preferably, the cobalt film 31 is formed via a PVD process and has a thickness ranging from 50 to 150 Å. A stacked structure of a cobalt film and a titanium nitride film may be used in place of the cobalt film 31. Referring to FIG. 2B, the cobalt film 31 is subjected to a rapid thermal process to react the cobalt film 31 with a surface of the impurity junction region 13, thereby forming a cobalt silicide layer 33. Preferably, the rapid thermal process comprises a first rapid thermal process performed at a temperature ranging from 650 to 750° C. for 10 to 30 seconds and a second rapid thermal process performed at a temperature ranging from 800 to 880° C. for 10 to 30 seconds. The first rapid thermal process may be omitted. Referring to FIG. 2C, an unreacted portion of the cobalt film 31 is removed. Preferably, the removal process is performed using a SC-1 solution which is a mixture solution of NH4OH, H2O2 and H2O. Now referring to FIG. 2D, a stacked structure 35 of a Ti film and a TiN film is formed on the semiconductor substrate 11 including the first and the second contact holes 27 and 29. Preferably, the Ti film has a thickness ranging from 100 to 200 Å and formed via a first PVD process and the TiN film has a thickness ranging from 100 to 400 Å and formed via a second PVD process. Thereafter, a conductive layer 37 is formed on the lower insulating film 25 including the first and the second contact holes 27 and 29. Preferably, the conductive layer 37 comprises tungsten. The conductive layer 37 is then patterned to form a conductive line pattern such as a bit line pattern or a metal wiring. As discussed earlier, in accordance with the present invention, a cobalt silicide layer is formed on a surface of a source/drain region to stabilize contact characteristics and improve reliability of the device. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiment is not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalences of such metes and bounds are therefore intended to be embraced by the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to method for forming conductive line of semiconductor device, and in particular to an improved method for forming conductive line of semiconductor device which provides improved contact resistance characteristics. 2. Description of the Background Art A bit line structure, which is a data I/O path of semiconductor device, comprises a polycide structure consisting of a polysilicon layer and a tungsten silicide layer. In case of a highly integrated and high-speed semiconductor device, a tungsten bit line having low resistance is used instead since this structure has a limitation due to high sheet resistance. Resistance stabilization is required for the tungsten bit lone because the contact resistance varies by the subsequent thermal processes. Generally, the contact resistance is greatly increased during a subsequent thermal process in a P+ region where a thick Ti film is formed due to loss of dopants in a source/drain region. Therefore, a bit line comprising a relatively thin Ti film is used. However, although the thin Ti film stabilizes the contact resistance of P+ region, contact resistances of N+ region and tungsten silicide layer of gate electrode are largely increased. Therefore, the thickness of the Ti film is adjusted so that the contact resistances of P+ region and N+ region and gate region have moderate values. However, as the contact area becomes smaller, the contact resistance, especially the contact resistance of gate electrode, is drastically increased as illustrated in FIG. 1 . The thickness of the Ti film must be increased to reduce the contact resistance. However, increase in the thickness of the Ti film increase the contact resistance of P+ region as described above, resulting in a degradation of device characteristic.
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<SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, it is an object of the present invention to provide method for forming conductive line of semiconductor device wherein a cobalt silicide layer is formed on a surface of a source/drain region to stabilize contact characteristics and improve reliability of the device. In order to achieve the above-described object of the invention, there is provided a method for forming conductive line of semiconductor device, comprising: forming a lower insulating film on a semiconductor substrate including a gate electrode and an impurity junction region; etching the lower insulating film to form a first contact hole exposing a top surface of the gate electrode and a second contact hole exposing the impurity junction region; forming a cobalt silicide layer on the impurity junction region exposed through the second contact hole; forming a stacked structure of a Ti film and a TiN film on the semiconductor substrate including the first and the second contact holes; forming a conductive layer on the lower insulating film including the first and the second contact holes; and patterning the conductive layer to form a conductive line pattern.
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20040630
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20060905
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20050630
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60221.0
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THAI, LUAN C
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METHOD FOR FORMING CONDUCTIVE LINE OF SEMICONDUCTOR DEVICE
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UNDISCOUNTED
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ACCEPTED
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10,879,218
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ACCEPTED
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Model-based synthesis of band moire images for authenticating security documents and valuable products
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The present invention relies on a band moiré image layout model capable of predicting the band moiré image layer layout produced when superposing a base band grating layer of a given layout and revealing line grating layer of a given layout. Both the base band grating layer and the revealing line grating layer may have a rectilinear or a curvilinear layout. The resulting band moiré image layout may also be rectilinear or curvilinear. Thanks to the band moiré image layout model, one can choose the layout of two layers selected from the set of base band grating layer, revealing line grating layer and band moiré image layer and obtain the layout of the third layer by computation, i.e. automatically. Base band grating layers and revealing line grating layers may be produced which yield, upon displacement of the revealing layer on top of the base layer or vice-versa, a band moiré image whose patterns move either along a predetermined direction or in the case of a concentric band moiré image, either inwards or outwards in respect to the center of the concentric moiré bands. In addition, it is possible to conceive a revealing line grating layer which when translated on top of the base band grating layer, generates a band moiré image which is subject to a periodic deformation. Furthermore, thanks also to the availability of a large number of geometric transformations and transformation variants (i.e. different values for the transformation constants), one may create documents having their own individualized document protection. A computing system may automatically generate upon request an individualized protected security document having specific base band grating and revealing line grating layouts. The computing system may then upon request generate and issue a security document incorporating the base band grating layer, a base band grating layer or a revealing line grating layer allowing to authenticate a previously issued security document. The presented methods may be used for creating an individualized protection for various categories of documents (banknotes, identity documents, checks, diploma, travel documents, tickets) and valuable products (optical disks, CDs, DVDs, CD-ROMs, packages for medical drugs, products with affixed labels, watches).
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1. A method for authenticating devices subject to counterfeiting attempts, said devices being selected from the set of security documents and valuable products, the method comprising the steps of: a) superposing a device with a base layer comprising a base band grating and a revealing layer comprising a revealing line grating, thereby producing a moire layer comprising a band moire image and b) comparing said band moire image with a reference band moire image and depending on the result of the comparison, accepting or rejecting the device, where the respective layouts of the base band grating layer, the revealing line grating layer and the band moiré image layer are related according to a band moiré image layout model, said band moiré image layout model enabling to choose the layout of two of said three layers and obtain the third layer by computation. 2. The method of claim 1, where the base band grating layer is synthesized by carrying out the steps of i) selecting a layout for the band moiré image layer; ii) selecting a layout for the revealing layer; iii) computing, according to the band moiré image layout model the layout of the base band grating layer. 3. The method of claim 2, where the revealing layer layout is curvilinear and where the superposition of base band grating and revealing line grating yields a rectilinear band moiré image. 4. The method of claim 2, where the revealing layer layout is rectilinear, where the superposition of base band grating and revealing line grating yields a curvilinear concentric band moiré image and where moving the revealing layer on top of the base layer has the effect of creating a dynamic band moiré image whose patterns move in an orientation selected from the set of inwards and outwards orientations. 5. The method of claim 2, where the revealing layer layout is periodic, where the superposition of base band grating and revealing line grating yields a curvilinear concentric band moiré image, and where moving the revealing layer on top of the base layer along a preferred orientation has the effect of creating a dynamic band moiré image whose patterns move in an orientation selected from the set of inwards and outwards orientations. 6. The method of claim 2, where the revealing layer layout is curvilinear, where the base band grating has the same curvilinear layout as the revealing layer and where the superposition of base band grating and revealing line grating yields according to the band moiré image layout model again the same curvilinear band moiré image layout. 7. The method of claim 2, where the revealing layer layout is laid out along spirals, where the superposition of base band grating and revealing line grating yields a curvilinear band moiré image, which when rotating the revealing layer on top of the base layer yield a dynamic band moiré image whose patterns move in an orientation selected from the set of inwards and outwards orientations. 8. The method of claim 2, where, according to said band moiré image layout model, the layout of the band moiré image is expressed by a geometric transformation M which transforms the band moiré image from a transformed space (xt,yt) to an original space (x,y), where the layout of the revealing line grating is expressed by a geometric transformation G which transforms the revealing line grating from the transformed space (xt,yt) into the original space (x,y), and where the layout of the base band grating is expressed by a geometric transformation H which transforms the base band grating from the transformed space (xt,yt) to the original space (x,y), said transformation H being a function of the transformations M and H. 9. The method of claim 8, where transformations M, G, and H are given as M(xt,yt)=(m1(xt,yt,m2(xt,yt)), G(xt,yt)=(x,g2(xt,yt)), and H(xt,yt)=(h1(xt,yt,h2(xt,yt)), and where said transformation H(xt,yt) is given by equations h 1 ( x t , y t ) = ( g 2 ( x t , y t ) - m 2 ( x t , y t ) ) · t x T r + m 1 ( x t , y t ) h 2 ( x t , y t ) = g 2 ( x t , y t ) · t y T r + m 2 ( x t , y t ) · T r - t y T r where Tr is the period of the revealing line grating in the original space and where (tx,ty) is the base band replication vector in the original space. 10. The method of claim 1, where the base layer is formed by several base band gratings and where moving the revealing layer on top of the base layer generates a moiré layer formed by several band moiré images which move in different orientations and at different speeds. 11. The method of claim 1, where displacing the revealing layer on top of the base layer generates a moiré layer formed of moving band moiré image patterns whose shapes remain intact. 12. The method of claim 1, where displacing the revealing layer in a direction different from a predetermined direction generates a moiré layer formed of moving band moiré image patterns whose shapes become deformed. 13. The method of claim 1, where displacing the revealing layer on top of the base layer generates a moiré layer formed of moving band moiré image patterns whose shapes become periodically deformed. 14. The method of claim 1, where the base layer and the revealing layer are partitioned onto different portions, each portion being characterized by its specific pair of matching revealing line and base band grating layouts, said layouts yielding, when superposed on top of one another, the same band moiré image layout. 15. The method of claim 1, where devices subject to counterfeiting attempts are individualized according to the geometric transformations transforming the base band grating and the revealing line grating from transformed space to the original space and according to the constants present in said transformations. 16. The method of claim 1, where the revealing line grating comprises lines selected from the group of continuous lines, dotted lines, interrupted lines and partially perforated lines. 17. The method of claim 1, where the base layer is imaged on an opaque support and the revealing layer on a transparent support. 18. The method of claim 1, where the base layer and the revealing layer are located on two different areas of the same device, thereby enabling the visualization of the moire pattern to be performed by superposition of the base layer and of the revealing layer of said device. 19. The method of claim 1, where the base layer is created by a process for transferring an image onto a support, said process being selected from the set comprising lithographic, photolithographic, photographic, electrophotographic, engraving, etching, perforating, embossing, ink jet and dye sublimation processes. 20. The method of claim 1, where the base layer is embodied by an element selected from the set of transparent devices, opaque devices, diffusely reflecting devices, paper, plastic, optically variable devices and diffractive devices. 21. The method of claim 1, where the revealing layer is an element selected from the set comprising an opaque support with transparent lines, cylindric microlenses and Fresnel zone lenses emulating the behavior of cylindric microlenses. 22. The method of claim 1, where the device subject to counterfeiting attempts is an element selected from the group of banknote, check, trust paper, identification card, passport, travel document, ticket, valuable document, watch, valuable product, label affixed on a valuable product, package of a valuable product. 23. The method of claim 1, where the base bands comprise multiple patterns selected from the set of typographic characters, logos, signs and symbols. 24. The method of claim 1 where the base bands comprise patterns printed using at least one non-standard ink, thus making its faithful reproduction difficult using the standard cyan, magenta, yellow and black printing colors available in common photocopiers and desktop systems. 25. The method of claim 1, where base bands comprise patterns reproduced with a metallic ink, thereby creating at specular observation angles strongly visible moiré patterns. 26. The method of claim 1, where an additional reference band moiré image printed on a layer selected from the set of base and revealing layers facilities verifying the authenticity of the device subject to counterfeiting attempts by comparing said reference band moiré image and the band moiré image produced by the superposition of base and revealing layers. 27. A device subject to counterfeiting attempts, said device being selected from the set of security documents and valuable products, said device comprising: (a) a base band grating layer whose base bands comprise base band patterns, and (b) a corresponding revealing line grating layer, where the superposition of the base band grating layer and of the revealing line grating layer form a band moiré image layer and where the respective layouts of the base band grating layer, the revealing line grating layer and the band moiré image layer are related according to a band moiré image layout model, said band moiré image layout model enabling to choose the layout of two of said three layers and obtain the third layer by computation. 28. The device subject to counterfeiting attempts of claim 27, where given a reference band moiré image layout and a given revealing line grating layout, the base band grating layout yielding in superposition with the revealing line grating layout the reference band moiré image layout is automatically computed according the band moiré image layout model. 29. The device subject to counterfeiting attempts of claim 27, where the revealing layer layout is curvilinear and where the superposition of base band grating and revealing line grating yields a rectilinear band moiré image. 30. The device subject to counterfeiting attempts of claim 27, where the revealing layer layout is rectilinear, where the superposition of base band grating and revealing line grating yields a curvilinear band moiré image and where moving the revealing layer on top of the base layer has the effect of creating a dynamic band moiré image whose patterns move in an orientation selected from the set of inwards and outwards orientations. 31. The device subject to counterfeiting attempts of claim 27, where the revealing layer layout is rectilinear, where the superposition of base band grating and revealing line grating yields a circular band moiré image, and where moving the revealing layer on top of the base layer along a preferred orientation has the effect of creating a dynamic band moiré image whose patterns move in an orientation selected from the set of inwards and outwards orientations. 32. The device subject to counterfeiting attempts of claim 27, where the revealing layer layout is curvilinear, where the base band grating has the same curvilinear layout as the revealing layer and where the superposition of base band grating and revealing line grating yield according to the band moiré image layout model again the same curvilinear band moiré image layout. 33. The device subject to counterfeiting attempts of claim 27, where the revealing layer layout is laid out along spirals, where the superposition of base band grating and revealing line grating yields a curvilinear band moiré image, and where rotating the revealing layer on top of the base layer yields a dynamic band moiré image whose patterns move in an orientation selected from the set of inwards and outwards orientations. 34. The device subject to counterfeiting attempts of claim 27, where, according to said band moiré image layout model, the layout of the band moiré image is expressed by a geometric transformation M which transforms the band moiré image from a transformed space (xt,yt) to an original space (x,y), where the layout of the revealing line grating is expressed by a geometric transformation G which transforms the revealing line grating from the transformed space (xt,yt) into the original space (x,y), and where the layout of the base band grating is expressed by a geometric transformation H which transforms the base band grating from the transformed space (xt,yt) to the original space (x,y), said transformation H being a function of the transformations M and H. 35. The device subject to counterfeiting attempts of claim 34, where transformations M, G, and H are given as M(xt,yt)=(m1(xt,yt,m2(xt,yt)), G(xt,yt)=(x,g2(xt,yt), and H(xt,yt)=(h1(xt,yt,h2(xt,yt)), and where said transformation H(xt,yt) is computed according to h 1 ( x t , y t ) = ( g 2 ( x t , y t ) - m 2 ( x t , y t ) ) · t x T r + m 1 ( x t , y t ) h 2 ( x t , y t ) = g 2 ( x t , y t ) · t y T r + m 2 ( x t , y t ) · T r - t y T r where Tr is the period of the revealing line grating in the original space and where (tx,ty) is the band replication vector in the original space. 36. The device subject to counterfeiting attempts of claim 27, where the base layer is formed by several base band gratings and where moving the revealing layer on top of the base layer generates a moiré layer formed by several band moiré images which move according to different orientations and speeds. 37. The device subject to counterfeiting attempts of claim 27, where displacing the revealing layer on top of the base layer generates a moiré layer formed of moving band moiré image patterns whose shapes remain intact. 38. The device subject to counterfeiting attempts of claim 27, where displacing the revealing layer in a direction different from a predetermined direction generates a moiré layer formed of moving band moiré image patterns whose shapes become deformed. 39. The device subject to counterfeiting attempts of claim 27, where displacing the revealing layer on top of the base layer generates a moiré layer formed of moving band moiré image patterns whose shapes become periodically deformed. 40. The device subject to counterfeiting attempts of claim 27, where the base layer and the revealing layer are partitioned into different portions, each portion being characterized by its pair of matching revealing line and base band grating layouts, said layouts, when superposed on top of one another, forming, despite being different between different portions, the same band moiré image layout. 41. The device subject to counterfeiting attempts of claim 34, where documents are individualized according to the geometric transformations transforming the base band grating and the revealing line grating from transformed space to the original space and according to constants present in said transformations. 42. The device subject to counterfeiting attempts of claim 27, where the revealing line grating comprises lines selected from the group of continuous lines, dotted lines, interrupted lines and partially perforated lines. 43. The device subject to counterfeiting attempts of claim 27, where the base layer is imaged on an opaque support and the revealing layer on a transparent support. 44. The device subject to counterfeiting attempts of claim 27, where the base layer and the revealing layer are located on two different areas of the same document, thereby enabling the visualization of the band moire image to be performed by superposition of the base layer and of the revealing layer of said document. 45. The device subject to counterfeiting attempts of claim 27, where the base layer is created by a process for transferring an image onto a support, said process being selected from the set comprising lithographic, photolithographic, photographic, electrophotographic, engraving, etching, perforating, embossing, ink jet and dye sublimation processes. 46. The device subject to counterfeiting attempts of claim 27, where the base layer is embodied by an element selected from the set of transparent devices, opaque devices, diffusely reflecting devices, paper, plastic, optically variable devices and diffractive devices. 47. The device subject to counterfeiting attempts of claim 27, where the revealing layer is an element selected from the set comprising an opaque support with transparent lines, cylindric microlenses and Fresnel zone lenses emulating the behavior of cylindric microlenses. 48. The device subject to counterfeiting attempts of claim 27, where said device is an element selected from the group of banknote, check, trust paper, identification card, passport, travel document, ticket, valuable document, watch, valuable product, label affixed on a valuable product, package of a valuable product. 49. The device subject to counterfeiting attempts of claim 27, where the base bands comprise multiple patterns selected from the set of typographic characters, logos, signs and symbols. 50. The device subject to counterfeiting attempts of claim 27 where the base bands comprise patterns printed using at least one non-standard ink, thus making its faithful reproduction difficult using the standard cyan, magenta, yellow and black printing colors available in common photocopiers and desktop systems. 51. The device subject to counterfeiting attempts of claim 27, where base bands comprise patterns reproduced with a metallic ink, thereby creating at specular observation angles strongly visible moiré patterns. 52. The device subject to counterfeiting attempts of claim 27, where an additional reference moiré image printed on a layer selected from the set of base and revealing layers facilities verifying the authenticity of the document by comparing said reference moiré image and the band moiré image produced by the superposition of base and revealing layers. 53. A document security computing and delivery system comprising a server system and client systems, said server system comprising: a) a repository module operable for registering documents and creating associations between document content information and corresponding band moiré image synthesizing information; b) a base band grating layer and revealing line grating layer synthesizing module operable for synthesizing base band grating layers and revealing line grating layers according to corresponding band moiré image synthesizing information; c) an interface module operable for receiving requests from client systems, operable for interacting with a base band grating layer and revealing line grating layer synthesizing module and further operable for delivering security documents, base band grating layers and revealing line grating layers to the client systems; where the base band grating layer and revealing line grating layer synthesizing module is operable for synthesizing base band gratings and revealing line gratings according to a band moiré image layout model, said band moiré image layout model enabling to choose the layout of two layers selected from the set of base band grating layer, revealing line grating layer and band moiré image layer and to obtain the layout of the third layer by computation. 54. The document security computing and delivery system of claim 53, where the band moiré image synthesizing information comprises: i) a reference band moiré image in an original coordinate space; ii) a preferred revealing line grating period Tr in the original coordinate space; iii) a moiré displacement orientation β in the original space; and iv) transformations G and M mapping respectively the revealing layer and the band moiré image layer from a transformed coordinate space to the original coordinate space. 55. The document security computing and delivery system of claim 53, where the band moiré image synthesizing information comprises: i) a reference band moiré image in an original coordinate space; ii) a preferred revealing line grating period Tr in the original coordinate space; iii) a moiré displacement orientation β in the original space; and iv) transformations G and H mapping respectively the revealing line grating layer and the base band grating layer from the transformed space to the original space. 56. The document security computing and delivery system of claim 54, where the base band grating layer and revealing line grating layer synthesizing module is also operable for computing from the transformations G and M mapping respectively the revealing layer and the band moiré image layer from the transformed space to the original space a transformation H mapping the base band layer from the transformed space to the original space. 57. The document security computing and delivery system of claim 53, where the client system is operable for emitting document registration requests, operable for emitting security document synthesizing requests, operable for emitting base band grating layer synthesizing requests and operable for emitting revealing line grating synthesizing requests.
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BACKGROUND OF THE INVENTION The present invention relates generally to the field of anti-counterfeiting and authentication methods and devices and, more particularly, to methods, security devices and apparatuses for authenticating documents and valuable products by band moiré patterns. Counterfeiting of documents such as banknotes is becoming now more than ever a serious problem, due to the availability of high-quality and low-priced color photocopiers and desk-top publishing systems. The same is also true for other valuable products such as CDs, DVDs, software packages, medical drugs, watches, etc., that are often marketed in easy to falsify packages. The present invention is concerned with providing a novel security element and authentication means offering enhanced security for devices needing to be protected against counterfeits, such as banknotes, checks, credit cards, identity cards, travel documents, valuable business documents, industrial packages or any other valuable products. The theory on which the present invention relies will be published at the beginning of August 2004, as a scientific contribution: “Band Moiré Images”, by R: D. Hersch and S. Chosson, SIGGRAPH'2004, ACM Computer Graphics Proceedings, Vol. 23, No. 3. Various sophisticated means have been introduced in the prior art for counterfeit prevention and for authentication of documents or valuable products. Some of these means are clearly visible to the naked eye and are intended for the general public, while other means are hidden and only detectable by the competent authorities, or by automatic devices. Some of the already used anti-counterfeit and authentication means include the use of special paper, special inks, watermarks, micro-letters, security threads, holograms, etc. Nevertheless, there is still an urgent need to introduce further security elements, which do not considerably increase the cost of the produced documents or goods. Moiré effects have already been used in prior art for the authentication of documents. For example, United Kingdom Pat. No. 1,138,011 (Canadian Bank Note Company) discloses a method which relates to printing on the original document special elements which, when counterfeited by means of halftone reproduction, show a moiré pattern of high contrast. Similar methods are also applied to the prevention of digital photocopying or digital scanning of documents (for example, U.S. Pat. No. 5,018,767, inventor Wicker). In all these cases, the presence of moiré patterns indicates that the document in question is counterfeit. Other prior art methods, on the contrary, take advantage of the intentional generation of a moiré pattern whose existence, and whose precise shape, are used as a means of authenticating the document. One known method in which a moiré effect is used to make visible a hidden pattern image encoded within a document (see background of U.S. Pat. No. 5,396,559 to McGrew, background of U.S. Pat. No. 5,901,484 to Seder, U.S. Pat. No. 5,708,717 to Alasia and U.S. Pat. No. 5,999,280 to Huang) is based on the physical presence of that image on the document as a latent image, using the technique known as “phase modulation”. In this technique, a line grating or a random screen of dots is printed on the document, but within the pre-defined borders of the latent image on the document the same line grating (or respectively, the same random dot-screen) is printed at a different phase, or possibly at a different orientation. For a layman, the latent image thus printed on the document is difficult to distinguish from its background; but when a revealing layer comprising an identical, but unmodulated, line grating or grating of lenticular lenses (respectively, random dot-screen) is superposed on the document, thereby generating a moiré effect, the latent image pre-designed on the document becomes clearly visible, since within its pre-defined borders the moiré effect appears in a different phase than in the background. Such a latent image may be recovered, since it is physically present on the document and only filled by lines at different phases or by a different texture. A second limitation of this technique resides in the fact that there is no enlargement effect: the pattern image revealed by the superposition of the base layer and of the revealing transparency has the same size as the latent pattern image. It should be stressed the disclosed band moire image synthesizing methods completely differ from the above mentioned technique of phase modulation since no latent image is present when generating a band moire image and since the band moiré image pattern shapes resulting from the superposition of a base band grating and a revealing line grating are a transformation of the original pattern shapes embedded within the base band grating. This transformation comprises always an enlargement, and possibly a rotation, a shearing, a mirroring, and/or a bending transformation. In addition, in the present invention, base band grating and revealing line grating layers can be created where translating respectively rotating the revealing layer on top of the base layer yields a displacement of the band moiré image patterns. Phase based modulation techniques allowing to hide latent images within a base layer are not capable of smoothly displacing and possibly transforming the revealed latent image when moving the revealing layer on top of the base layer. For example, they are unable to create a continuous displacement of the band moiré image patterns, such as for example the band moiré image patterns moving towards the center of a circular band moiré image layout. A further means of distinguishing phase modulation techniques from band moirés consists in verifying, once the revealing line grating is laid out on top of the base layer, if respectively a moiré pattern is produced by sampling only a single instance (i.e. one latent pattern image) or multiple instances of a base layer pattern (i.e. multiple base bands incorporating each one an instance of the base band pattern). U.S. Pat. No. 5,999,280, Holographic Anti-Imitation Method and Device for preventing unauthorized reproduction, inventor P. P. Huang, issued Dec. 7, 1999, discloses a holographic anti-imitation method and device where the superposition of a viewing device on top of a hidden pattern merged on a background pattern allows to visualize that hidden pattern. This disclosure relies on a technique similar to the phase modulation technique presented in the background section of U.S. Pat. No. 5,396,559 to McGrew, implemented on a holographic device. In contrast to U.S. Pat. No. 5,999,280, our invention relies on a completely different principle: several instances of the base band patterns are sampled and produce band moire image patterns which are enlarged and transformed instances of these base band patterns. Furthermore, our invention allows to generate dynamic band moire images, i.e. animations with dynamically behaving band moire image pattern shapes, which are impossible to achieve with patent U.S. Pat. No. 5,999,280. In U.S. Pat. No. 5,712,731 (Drinkwater et al.) a moiré based method is disclosed which relies on a periodic 2D array of microlenses. However, this last disclosure has the disadvantage of being limited only to the case where the superposed revealing structure is a microlens array and the periodic structure on the document is a constant 2D dot-screen with identical dot-shapes replicated horizontally and vertically. Thus, in contrast to the present invention, that invention excludes the use of gratings of lines as the revealing layer, both imaged on a transparent support (e.g. film) or as a grating of cylindric microlenses. Other moiré based methods disclosed by Amidror and Hersch in U.S. Pat. No. 6,249,588 and its continuation-in-part U.S. Pat. No. 5,995,638 rely on the superposition of arrays of screen dots which yields a moiré intensity profile indicating the authenticity of the document. These inventions are based on specially designed 2D periodic structures, such as dot-screens (including variable intensity dot-screens such as those used in real, gray level or color halftoned images), pinhole-screens, or microlens arrays, which generate in their superposition periodic moiré intensity profiles of chosen colors and shapes (typographic characters, digits, the country emblem, etc.) whose size, location and orientation gradually vary as the superposed layers are rotated or shifted on top of each other. In a third invention, U.S. patent application Ser. No. 09/902,445, Amidror and Hersch disclose new methods improving their previously disclosed methods mentioned above. These new improvements make use of the theory developed in the paper “Fourier-based analysis and synthesis of moirés in the superposition of geometrically transformed periodic structures” by I. Amidror and R. D. Hersch, Journal of the Optical Society of America A, Vol. 15, 1998, pp. 1100-1113 (hereinafter, “[Amidror98]”), and in the book “The Theory of the Moiré Phenomenon” by I. Amidror, Kluwer, 2000. According to this theory, said invention discloses how it is possible to synthesize aperiodic, geometrically transformed dot screens which in spite of being aperiodic in themselves, still generate, when they are superposed on top of one another, periodic moiré intensity profiles with undistorted elements, just like in the periodic cases disclosed by Hersch and Amidror in their previous U.S. Pat. No. 6,249,588 and its continuation-in-part U.S. Pat. No. 5,995,638. U.S. patent application Ser. No. 09/902,445 further disclosed how cases which do not yield periodic moirés can still be advantageously used for anticounterfeiting and authentication of documents and valuable products. In U.S. patent application Ser. No. 10/183,550 “Authentication with build-in encryption by using moiré intensity profiles between random layers”, inventor Amidror discloses how a moiré intensity profile is generated by the superposition of two specially designed random or pseudo-random dot screens. An advantage of that invention relies in its intrinsic encryption system offered by the random number generator used for synthesizing the specially designed random dot screens. However, the disclosures above made by inventors Hersch and Amidror (U.S. Pat. No. 6,249,588, U.S. Pat. No. 5,995,638. U.S. patent application Ser. No. 09/902,445) or Amidror (U.S. application Ser. No. 10/183,550) making use of the moiré intensity profile to authenticate documents have two limitations. The first limitation is due to the fact that the revealing layer is made of dot screens, i.e. of a set (2D array) of tiny dots laid out on a 2D surface. When dot screens are embodied by an opaque layer with tiny transparent dots or holes (e.g. a film with small transparent dots), only a limited amount of light is able to traverse the dot screen and the resulting moiré intensity profile is not easily visible. In these inventions, to make the moiré intensity profile clearly visible, one needs to work in transparent mode; both the revealing and the base layers need to be placed in front of a light source and the base layer should be preferably printed on a partly transparent support. In reflective mode, one needs to use a microlens array as master screen which, thanks to the light focussing capabilities of the lenses, make the moiré intensity profile clearly visible. The second limitation is due to the fact that the base layer is made of a two-dimensional array of similar dots (dot screen) where each dot has a very limited space within which only a few tiny shapes such as a few typographic characters or a single logo must be placed. This space is limited by the 2D frequency of the dot screen, i.e. by its two period vectors. The higher the 2D frequency, the less space there is for placing the tiny shapes which, when superposed with a 2D circular dot screen as revealing layer, produce as 2D moiré an enlargement of these tiny shapes. In U.S. patent application Ser. No. 10/270,546 (filed 16th of Oct. 2002, “Authentication of documents and articles by moiré patterns”, inventors Hersch and Chosson), a significant improvement was made by the discovery that a rectilinear base band grating incorporating original shapes superposed with a revealing straight line grating yields rectilinear moiré bands comprising moiré shapes which are a linear transformation of the original shapes incorporated within the base band grating. These moiré bands form a band moiré image. Since band moiré have a much better light efficiency than moiré intensity profiles relying on dots screens, band moiré images can be advantageously used in all case where the previous disclosures relying on 2D screens fail to show strong enough moiré patterns. In particular, the base band grating incorporating the original pattern shapes may be printed on a reflective support and the revealing line screen may simply be a film with thin transparent lines. Due to the high light efficiency of the revealing line screen, the band moiré patterns representing the transformed original band patterns are clearly revealed. A further advantage of band moiré images resides in the fact that it may comprise a large number of patterns, for example one or several words, one or several sophisticated logos, one or several symbols, and one or several signs. U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson), describes the layout of rectilinear band moiré images, when the layouts of base layer and the revealing layer are known. However it does not tell in which direction and at which speed the moiré shape moves when translating the rectilinear revealing layer on top of the rectilinear base layer. Furthermore, since it does not disclose a model for predicting the layout of the moiré image that can be produced when superposing a curvilinear base layer and a curvilinear revealing layer, band moirés image relying on curvilinear base or revealing layers need to be generated by a trial and error procedure. One tries first to generate examples of curvilinear line moirés produced by the superposition of line grating (according to the theory describing prior art line grating, see the article by I. Amidror and R. D. Hersch, Fourier-based analysis and synthesis of moirés in the superposition of geometrically transformed periodic structures, Journal of the Optical Society of America A, Vol. 15, 1998; pp. 1100-1113 or the book of I. Amidror, The Theory of the Moiré Phenomenon, Kluwer, 2000, pages 249-352). Then, one replaces curvilinear lines of the line grating by bands, yielding a band grating. And finally, one verifies if the result is visually pleasing or not, and if not modifies the parameters of the base and revealing transformations and visualize again the results. When one of the layers layout is curvilinear, this trial and error method does not allow to compute a base band grating layer layout given a reference band moiré image layout and a revealing line grating layout. In addition, since the method relies on trial and error, it does not support the derivation of complicated geometric transformations, such as computing a base layer, which in superposition with a revealing layer forming a spiral shaped line grating yields a meaningful, visually pleasant band moiré image. The only reference band moiré image available with the trial and error method is the band moiré image produced by superposing the base and revealing layer derived thanks to the trial and error procedure. Furthermore, U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson) does neither give a precise technique for generating a reference rectilinear band moiré image layout with curvilinear base and revealing layer layouts nor does it give a means of generating a desired reference curvilinear band moiré image layout with a predetermined rectilinear or curvilinear revealing layer layout. U.S. patent application Ser. No. 10/270,546 teaches a method for creating variations of the appearing moiré patterns when moving the revealing layer on top of the base layer, however these variations rely only on modifications of the shapes embedded within the base band layer and do not rely, as in the present disclosure, on the geometric transformations of the base layer and/or the revealing layer. The present disclosure provides a band moiré image layout model allowing to compute not only the layout of a rectilinear band moiré image produced by superposing a rectilinear base band layer and a rectilinear revealing layer, but also in which direction and at which speed the rectilinear moiré shapes move when translating a the rectilinear revealing layer on top of the rectilinear base layer. For a curvilinear base layer and a curvilinear or rectilinear revealing layer, that model computes exactly the layout of the resulting rectilinear or curvilinear band moiré image obtained by superposing the base and revealing layers. Furthermore, one may specify a desired rectilinear or curvilinear band moiré image as well as one of the layers and the model is able to compute the layout of the other layer. Let us also note that the properties of the moiré produced by the superposition of two line gratings are well known (see for example K. Patorski, The moiré Fringe Technique, Elsevier 1993, pp. 14-16). Moiré fringes (moiré lines) produced by the superposition of two line gratings (i.e. set of lines) are exploited for example for the authentication of banknotes as disclosed in U.S. Pat. No. 6,273,473, Self-verifying security documents, inventors Taylor et al. Curved moiré fringes (moiré lines) produced by the superposition of curvilinear gratings are also known (see for example Oster G., Wasserman M., Zwerling C. Theoretical Interpretation of Moiré Patterns. Journal of the Optical Society of America, Vol. 54, No. 2, 1964, 169-175) and have been exploited for the protection of documents by a holographic security device (U.S. Pat. No. 5,694,229, issued Dec. 2, 1997, K. J. Drinkwater, B. W. Holmes). In U.S. patent application Ser. No. 10/270,546 as well as in the present invention, instead of using a line grating as base layer, we use as base layer a band grating incorporating in each band an image made of one-dimensionally compressed original patterns of varying shapes, sizes, intensities and possibly colors. Instead of obtaining simple moiré fringes (moiré lines) when superposing the base layer and the revealing line grating, we obtain a band moiré image which is an enlarged and transformed instance of the original band image. Joe Huck, a prepress professional, in his publication (2003) entitled “Mastering Moirés. Investigating Some of the Fascinating Properties of Interference Patterns, see also http://pages.sbcglobal.net/joehuck”, created band moiré images, both for artistic purposes and for creating designs incorporating moiré shapes floating within different perceived depth planes thanks to parallax effects. His publication only reports about vertically replicated horizontal base bands and a revealing layer made of horizontal lines, thereby generating moiré shapes moving only in the vertical direction. In contrast to the present invention, he neither provided a general-purpose framework for predicting the geometry of band moiré images as a function of base and revealing layer layouts, nor did he consider geometric transformations of base and revealing layers. In addition, he didn't consider applying band moiré images for document authentication. SUMMARY The present invention relates to the protection of devices which may be subject to counterfeiting attempts. Such devices comprise security documents such as banknotes, checks, trust papers, securities, identification cards, passports, travel documents, tickets, valuable business documents and valuable products such as optical disks, CDs, DVDs, software packages, medical products, watches. These devices need advanced authentication means in order to prevent counterfeiting attempts. The invention also relates to a document security computing and delivery system allowing to synthesize and deliver the security document as well as its corresponding authentication means. The present invention relies on a band moiré image layout model capable of predicting the band moiré image layer layout produced when superposing a base band grating layer of a given layout and a revealing line grating layer of a given layout. Both the base band grating layer and the revealing line grating layer may have a rectilinear or a curvilinear layout. The resulting band moiré image layout may also be rectilinear or curvilinear. Thanks to the band moiré image layout model, one can choose the layout of two layers selected from the set of base band grating layer, revealing line grating layer and band moiré image layer and obtain the layout of the third layer by computation, i.e. automatically. In contrast to the prior art invention described in U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson), there is no need to proceed according to a manual trial and error procedure in order to create a revealing line grating layer layout and a base band grating layer layout which yield upon superposition a visually attractive easily perceivable band moiré image. In the present invention, one may simply define the band moiré image layout as well as the revealing line grating layout and compute the corresponding base band grating layout, which when superposed with the specified revealing line grating layout generates the specified band moiré image layout. The present disclosure also describes methods for computing the direction and speed at which rectilinear moiré shapes move when translating the corresponding rectilinear revealing line grating layer on top of the rectilinear base band grating layer. Furthermore, base band grating layer and revealing line grating layer layouts may be produced which yield, upon displacement of the revealing layer on top of the base layer (or vice-versa), a band moiré image whose patterns move along one direction or in the case of a concentric band moiré image, inwards or outwards in respect to the center of concentric moiré bands. In addition, it is possible to conceive a periodically varying revealing line grating layer which when translated on top of the base band grating layer, generates a band moiré image which is subject to a periodic deformation. Furthermore, thanks to the availability of a large number of geometric transformations and transformation variants (i.e. different values for the transformation constants), one may create classes of documents where each class of documents has its own individualized document protection. In addition, thanks to the band moire layout model, it is possible to synthesize one band moiré image partitioned into different portions synthesized each one according to a different pair of matching geometric transformations. This makes it practically impossible for potential counterfeiters to resynthesize a base layer without knowing in detail the relevant geometric transformations as well as the constants used to synthesize the authentic base layer. Thanks to the band moire image layout model, a computing system may automatically generate upon request an individualized protected security document by creating for a given document content information a corresponding band moiré image layout information. This computing system may then upon request synthesize and issue the security document with its embedded base band grating layer, the base band grating layer or the revealing line grating layer. To further enhance the security of documents, it is possible to synthesize a base band grating layer with non-overlapping shapes of different colors, for example created with non-standard inks, such as iridescent inks, inks visible under UV light or metallic inks, i.e. inks which are not available in standard color copiers or printers. The base band grating and revealing line grating layers may be printed on various supports, opaque or transparent materials. The revealing layer may be embodied by a line grating imaged on an transparent support or by other means such as cylindric microlenses. Such cylindric microlenses offer a high light efficiency and allow to reveal band moiré image patterns whose base band grating patterns are imaged at a high frequency on the base band layer. The base band grating layer may also be reproduced on an optically variable device and revealed either by a line grating imaged on a transparent support, by cylindric microlenses, or by a diffractive device such as Fresnel zone plates emulating cylindric microlenses. The fact that the generated band moiré patterns are very sensitive to any microscopic variations in the base and revealing layers makes any document protected according to the present invention extremely difficult to counterfeit, and serves as a means to distinguish between a real document and a falsified one. The present invention offers an additional protection by allowing to produce individual layouts either for individual or for classes of security documents. In addition, thanks to the band moiré image layout model, both the base band grating layer and the revealing line grating layer may be automatically generated. In the present disclosure different variants of the invention are described, some of which may be disclosed for the use of the general public (hereinafter: “overt” features), while other variants may be hidden (for example one of the set of base bands in a base layer combining multiple sets of base bands) and only detected by the competent authorities or by automatic devices (hereinafter: “covert” features). BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, one may refer by way of example to the accompanying drawings, in which: FIGS. 1A and 1B show respectively a grating of lines and a 2D circular dot screen (prior art); FIGS. 2A and 2B show the generation of moiré fringes when two line gratings are superposed (prior art); FIG. 3 shows the moiré fringes and band moiré patterns generated by the superposition of a revealing line grating and of a base layer incorporating a grating of lines on the left side and base bands with the patterns “EPFL” on the right side (U.S. patent application Ser. No. 10/270,546, Hersch & Chosson); FIG. 4 shows separately the base layer of FIG. 3; FIG. 5 shows separately the revealing layer of FIG. 3; FIG. 6 shows that the produced band moiré patterns are a transformation of the original base band patterns; FIG. 7 shows schematically the superposition of oblique base bands and of a revealing line grating (horizontal continuous lines); FIG. 8 shows oblique base bands Bi, horizontal base bands Hi, corresponding oblique moiré bands Bi′ and corresponding horizontal moiré bands Hi′; FIG. 9 shows the linear transformation between the base band parallelogram ABCD and the moiré parallelogram ABEF; FIG. 10 shows a possible layout of text patterns along the oblique base bands and the corresponding revealed band moiré text patterns; FIG. 11 shows another layout of text patterns along the horizontal base bands, and the corresponding moiré text patterns; FIG. 12A shows a base layer comprising three sets of rectilinear base bands with different periods and orientations; FIG. 12B shows a rectilinear revealing layer; FIG. 12C shows the superposition of the rectilinear revealing layer shown in FIG. 12B and of the base layer shown in FIG. 12A; FIG. 12D shows the same superposition as in FIG. 12C, but with a translated revealing layer; FIGS. 13A, 13B, 13C and 13D show respectively the base layer, the revealing layer and superpositions of base layer and revealing layer according to two different relative superposition positions yielding a multicomponent moiré image inspired from the US flag, where different band moiré image components move along different orientations at different speeds; FIG. 14. shows the parameters of the base layer shown in FIG. 13A and of the revealing layer shown in FIG. 13B, expressed in pixels (e.g. at 1200 dpi); FIG. 15A shows a rectilinear reference moiré image; FIGS. 15B and 16B illustrate respectively the application of a same geometric transformation to both the base and the revealing layer, yielding a circular base band layer (FIG. 15B) and a circular revealing layer in the transformed space (FIG. 16B); FIG. 16A shows the curvilinear circular band moiré image resulting from the superposition of the base layer shown in FIG. 15B and of the revealing layer shown in FIG. 16B; FIGS. 17A and 17B show the indices of oblique base band borders n, of revealing lines m and of corresponding moiré band border lines k before (FIG. 17A) and after (FIG. 17B) applying the geometric transformations; FIG. 18 shows a base band parallelogram Pλt of orientation t linearly transformed into a moiré parallelogram Pλt′ of the same orientation; FIGS. 19A and 19B shows respectively the geometrically transformed base and revealing layers of respectively FIGS. 12A and 12B with a revealing layer transformation producing cosinusoidal revealing lines; FIGS. 19C and 19D show the rectilinear moire images induced by the superposition of the transformed layers shown in FIGS. 19A and 19B for two different relative vertical positions; FIGS. 20A and 20B show respectively the geometrically transformed base and revealing layers of respectively FIGS. 12A and 12B with a revealing layer transformation producing a circular revealing layer; FIG. 20C shows the band moire image induced by the exact superposition of the transformed layers shown in FIGS. 20A and 20B; FIG. 20D shows the deformed moire image induced by the superposition, when slightly translating the revealing layer (FIG. 20B) on top of the base layer (FIG. 20A); FIG. 21A shows a reference band moire image layout and FIG. 21B the corresponding band moiré image with the same layout, obtained thanks to the band moire layout model; FIG. 22A shows the transformed base layer computed according to the band moire layout model and FIG. 22B the rectilinear revealing layer used to generate the moiré image shown in FIG. 21B; FIG. 23A shows a cosinusoidal revealing layer and FIG. 23B a base layer transformed according to the band moire layout model; FIG. 24 shows the resulting band moiré image which has the same layout as the desired reference moiré image shown in FIG. 21A; FIG. 25 shows a spiral shaped revealing layer; FIG. 26 shows the curvilinear base layer computed so as to form, when superposed with the spiral shaped revealing layer of FIG. 25 a circular band moiré image; FIG. 27 shows the circular band moiré image obtained when superposing the revealing layer of FIG. 26 and the base layer of FIG. 27; FIGS. 28A and 28B show respectively a base and a revealing layer partitioned into different portions created according to different pairs of matching geometric transformations, laid out into distinct areas; FIG. 29 shows the band moiré image obtained by superposing the base layer shown in FIG. 28A and the revealing layer shown in FIG. 28B, which, despite being composed of several distinct portions, has the same layout as the desired reference moiré image shown in FIG. 21A; FIGS. 30A and 30B, illustrate schematically a possible embodiment of the present invention for the protection of optical disks such as CDs, CD-ROMs and DVDs; FIG. 31 illustrates schematically a possible embodiment of the present invention for the protection of products that are packed in a box comprising a sliding part; FIG. 32 illustrates schematically a possible embodiment of the present invention for the protection of pharmaceutical products; FIG. 33 illustrates schematically a possible embodiment of the present invention for the protection of products that are marketed in a package comprising a sliding transparent plastic front; FIG. 34 illustrates schematically a possible embodiment of the present invention for the protection of products that are packed in a box with a pivoting lid; FIG. 35 illustrates schematically a possible embodiment of the present invention for the protection of products that are marketed in bottles (such as whiskey, perfumes, etc.); FIG. 36 shows a watch, whose armband comprises a moving revealing line grating layer yielding a band moiré image; and FIG. 37 illustrates a block diagram of a computing system operable for delivering base band grating and revealing line grating layers associated to the security documents to be delivered, respectively authenticated. DETAILED DESCRIPTION OF THE INVENTION In U.S. Pat. No. 6,249,588, its continuation-in-part U.S. Pat. No. 5,995,638, U.S. patent application Ser. No. 09/902,445, Amidror and Hersch, and in U.S. patent application Ser. No. 10/183'550, Amidror disclose methods for the authentication of documents by using the moiré intensity profile. These methods are based on specially designed two-dimensional structures (dot-screens, pinhole-screens, microlens structures), which generate in their superposition two-dimensional moiré intensity profiles of any preferred colors and shapes (such as letters, digits, the country emblem, etc.) whose size, location and orientation gradually vary as the superposed layers are rotated or shifted on top of each other. In reflective mode and with a revealing layer (called master screen in the above mentioned inventions) embodied by an opaque layer with tiny transparent dots or holes (e.g. a film with tiny transparent holes), the amount of reflected light is too low and therefore the moiré shapes are nearly invisible. Therefore, in reflective mode, the revealing layer to be used in these inventions must be a microlens array. In addition, in these inventions, the base layer is made of a set (2D array) of similar dots (dot screen) where each dot has a very limited space within which tiny shapes such as characters, digits or logos must be placed. This space is limited by the 2D frequency of the dot screen, i.e. by its two period vectors. The higher the 2D frequency, the less space there is for placing the tiny shapes which, when superposed with a 2D circular dot screen as revealing layer, produce as 2D moiré an enlargement of these tiny shapes. Since much more light passes through a line grating of a given period and relative aperture than through a dot screen of the same period and of the same relative aperture as dot diameter, band moiré images induced by line gratings have a much higher dynamic range than 2D moirés images obtained by superposing a dot screen and an array of tiny holes. In U.S. patent application Ser. No. 10/270,546 (Hersch & Chosson), the present inventors proposed to use a line grating as revealing layer and to introduce as base layer a base band grating made of replicated bands comprising freely chosen flat patterns or flat images (FIGS. 3,4,5). The present disclosure provides new inventive steps in respect to U.S. patent application Ser. No. 10/270,546 (Hersch & Chosson) by disclosing a model (hereinafter called “band moire image layout model”) allowing the computation of the direction and the speed in which rectilinear band moiré image shapes move when translating a rectilinear revealing layer on top of a rectilinear base layer. Furthermore, given any layout of rectilinear or curvilinear base and revealing layers, the band moire layout model computes the layout of the resulting rectilinear or curvilinear band moiré image obtained by superposing the base and revealing layers. In addition, one may specify a desired rectilinear or curvilinear band moiré image as well as one of the layers and the band moire layout model is able to compute the layout of the other layer. A base band grating differs from a line grating by having instead of a 1D intensity profile a 2D intensity profile, i.e. an intensity profile which varies according to the current position both in the transversal and in the longitudinal line directions. A base band becomes a full 2D image of its own, which can be revealed by superposing on the corresponding base band grating a revealing layer made of thin transparent lines. It is well known from the prior art that the superposition of two line gratings generates moiré fringes, i.e. moiré lines as shown in FIG. 2A (see for example K. Patorski, The Moiré Fringe Technique, Elsevier 1993, pp. 14-16). One prior art method of analyzing moiré fringes relies on the indicial equations of the families of lines composing the base and revealing layer line gratings. The moiré fringes formed by the superposition of these indexed line gratings form a new family of indexed lines whose equation is deduced from the equation of the base and revealing layer line families (see Oster G., Wasserman M., Zwerling C. Theoretical Interpretation of Moiré Patterns. Journal of the Optical Society of America, Vol. 54, No. 2, 1964, 169-175, hereinafter referenced as [Oster 64]). FIG. 2B shows the oblique base lines with indices n=−1, 0, 1, 2, 3, . . . , the horizontal revealing layer lines with indices m=0, 1, 2, 3, 4, . . . and the moiré lines with indices k=1, 0, −1, −2 . . . . The moiré fringes comprise highlight moiré lines connecting the intersections of oblique and horizontal base lines and dark moiré lines located between the highlight moiré lines. Each highlight moiré line can be characterized by an index k=n−m (1) The family of oblique base lines is described by y=tan θ·x+n·λ·tan θ (2) where θ is the angle of the oblique base lines and λ the horizontal spacing between successive base lines (FIG. 2B). The family of horizontal revealing lines is described by y=m·Tr (3) By expressing indices n and m as a function of x and y, n = y - x · tan θ λ · tan θ m = y T r ( 4 ) and by expressing k according to equation (1) k = n - m = y · T r - x · T r · tan θ - y · λ · tan θ λ · T r · tan θ ( 5 ) we deduce the equation describing the family of moiré lines y = x · T r · tan θ T r - λ · tan θ + k · T r · λ · tan θ T r - λ · tan θ ( 6 ) Equation (6) fully describes the family of subtractive moiré lines: the moiré line orientation is given by the slope of the line family and the moiré period can be deduced from the vertical spacing between two successive lines of the moiré line family. In the section on curvilinear band moirés, we make use of indicial equation (6) in order to deduce the transformation of the moiré images whose base and revealing layers are geometrically transformed. Both in U.S. patent application Ser. No. 10/270,546 and in the present invention, we extend the concept of line grating to band grating. A band of width Tb corresponds to one line instance of a line grating (of period Tb) and may incorporate as original shapes any kind of patterns, which may vary along the band, such as black white patterns (e.g. typographic characters), variable intensity patterns and color patterns. For example, in FIG. 3, a line grating 31 and its corresponding band grating 32 incorporating in each band the vertically compressed and mirrored letters EPFL are shown. When revealed with a revealing line grating 33, one can observe on the left side the well known moiré fringe 35 and on the right side, band moiré patterns 34 (EPFL), which are an enlargement and transformation of the letters located in the base bands. These band moiré patterns 34 have the same orientation and repetition period as the moiré fringes 35. FIG. 4 shows the base layer of FIG. 3 and FIG. 5 shows its revealing layer. The revealing layer (line grating) may be photocopied on a transparent support and placed on top of the base layer. The reader may verify that when shifting the revealing line grating vertically, the band moiré patterns also undergo a vertical shift. When rotating the revealing line grating, the band moiré patterns are subject to a shearing and their global orientation is accordingly modified. FIG. 3 also shows that the base band layer (or more precisely a single set of base bands) has only one spatial frequency component given by period Tb. Therefore, while the space between each band is limited by period Tb, there is no spatial limitation along the band. Therefore, a large number of patterns, for example a text sentence, may be placed along each band. This is an important advantage over the prior art moiré profile based authentication methods relying on two-dimensional structures (U.S. Pat. No. 6,249,588, its continuation-in-part U.S. Pat. No. 5,995,638, U.S. patent application Ser. No. 09/902,445, Amidror and Hersch, and in U.S. patent application Ser. No. 10/183'550, Amidror). In the section “Geometry of rectilinear band grating moirés”, we establish the part of the band moiré image layout model which describes the superposition of a rectilinear base band grating layer and a rectilinear revealing line grating layer. The base band layer comprises base bands replicated according to any replication vector t (FIG. 7). This part of the model gives the linear transformation between the one-dimensionally compressed image located within individual base bands and the band moiré image. It also gives the vector specifying the orientation along which the band moiré image moves when displacing the revealing layer on top of the base layer or vice-versa. The linear transformation comprises an enlargement (scaling), possibly a rotation, possibly a shearing and possibly a mirroring of the original patterns. Note that all drawings showing base band patterns and revealing line grating layers are strongly enlarged in order to allow to photocopy the drawings and verify the appearance of the moiré patterns. However, in real security documents, the base band period Tb and the revealing line grating period Tr are much lower, making it very difficult or impossible to make photocopies of the base band patterns with standard photocopiers or desktop systems. Terminology The term “devices which may be subject to counterfeiting attempts” refers to security documents such as banknotes, checks, trust papers, securities, identification cards, passports, travel documents, tickets, valuable business documents such as contracts, etc. and to valuable products such as optical disks, CDs, DVDs, software packages, medical products, watches, etc. These devices are protected by incorporating into them or associating to them a base layer comprising a base band grating and a revealing layer comprising a line grating made of thin transparent lines. Such devices are authenticated by placing the revealing layer on top of the base layer and by verifying if the resulting band moiré image has the same layout as the original reference band moiré image or by moving the revealing layer on top of the base layer and verifying if the resulting dynamic band moiré image has the expected behavior. Expected behaviors are for example band moiré image patterns remaining intact while moving along specific orientations, band moiré image patterns moving radially, or band moiré image patterns subject to a periodic deformation. The term “image” characterizes images used for various purposes, such as illustrations, graphics and ornamental patterns reproduced on various media such as paper, displays, or optical media such as holograms, kinegrams, etc. . . . . Images may have a single channel (e.g. gray or single color) or multiple channels (e.g. RGB color images). Each channel comprises a given number of intensity levels, e.g. 256 levels). Multi-intensity images such as gray-level images are often called bytemaps. Printed images may be printed with standard colors (cyan, magenta, yellow and black, generally embodied by inks or toners) or with non-standard colors (i.e. colors which differ from standard colors), for example fluorescent colors (inks), ultra-violet colors (inks) as well as any other special colors such as metallic or iridescent colors (inks). The term “band moiré image” refers to the image obtained when superposing a base band grating layer and a revealing line grating layer. The terms band moiré image and band moiré image layer are used interchangeably. Each base band (FIG. 6, 62) of a base band grating comprises a base band image. The base band image may comprise various patterns (e.g. the “EPFL” pattern in base band 62), black-white, gray or colored, with pattern shapes forming possibly typographic characters, logos, symbols or line art. These patterns are revealed as band moiré image patterns (or simply band moiré patterns) within the band moiré image (FIG. 6, 64) produced when superposing the revealing line grating layer on top of the base band grating layer. A base layer comprising a repetition of base bands is called base band grating layer or simply base band grating, base band layer or when the context is unambiguous, base layer. Similarly, a revealing layer made of a repetition of revealing lines is called revealing line grating layer or simply revealing line grating or when the context is unambiguous, revealing layer. Both the base band gratings and the revealing line gratings may either be rectilinear or curvilinear. If they are rectilinear, the band borders, respectively the revealing lines, are straight. If they are curvilinear, the band borders, respectively the revealing lines, are curved. In the present invention, curvilinear base band gratings and curvilinear revealing line gratings are generated from their corresponding rectilinear base band and revealing line gratings by geometric transformations. The geometric transformations transform the gratings from transformed coordinate space (simply called transformed space) to the original coordinate space (simply called original space). This allows to scan pixel by pixel and scanline by scanline the base grating layer, respectively the revealing line grating layer in the transformed space and find the corresponding locations of the corresponding original base grating layer, respectively revealing line grating layer within the original space. In the present invention, we use the term line gratings in a generic way: a line grating may be embodied by a set of transparent lines (e.g. FIG. 1A, 11) on an opaque or partially opaque support (e.g. FIG. 1A, 10), by cylindric microlenses (also called lenticular lenses) or by diffractive devices (Fresnel zone plates) acting as cylindric microlenses. Sometimes, we use instead of the term “line grating” the term “grating of lines”. In the present invention, these two terms should be considered as equivalent. In addition, lines gratings need not be made of continuous lines. A revealing line grating may be made of interrupted lines and still produce band moiré patterns. In the literature, line gratings are often sets of parallel lines, where the white (or transparent) part (τ in FIG. 2A) is half the full width, i.e. with a ratio of τ/T=½. In the present invention, regarding the line gratings used as revealing layers, the relative width of the transparent part (aperture) is generally lower than ½, for example ⅕, ⅛, or 1/10. The term “printing” is not limited to a traditional printing process, such as the deposition of ink on a substrate. Hereinafter, it has a broader signification and encompasses any process allowing to create a pattern or to transfer a latent image onto a substrate, for example engraving, photolithography, light exposition of photo-sensitive media, etching, perforating, embossing, thermoplastic recording, foil transfer, ink-jet, dye-sublimation, etc. The Geometry of Rectilinear Band Moiré Images FIG. 6 shows the superposition of an oblique base band grating and of a horizontal revealing line grating. Since the superposition of a base band grating and revealing line grating with any freely chosen orientations can always be rotated so as to bring the revealing line grating in the horizontal position, we will in the following explanations consider such a layout, without loss of generality. FIG. 6 shows that the moiré patterns are a transformation of the original base band patterns 61 that are located in the present embodiment within each repetition of the base bands 62 of the base band layer. FIG. 6 also shows the equivalence between the original oblique base band 61 and the derived horizontal base band 63, parallel to the horizontally laid out revealing layer 65. The geometric model we are describing relies on the assumption that the revealing line grating is made of transparent straight lines with a small relative aperture, i.e. the revealing line grating can be assimilated to a grating of sampling lines. Let us analyze how the revealing line grating (dashed lines in FIG. 7) samples the underlying base layer formed by replications of oblique base band B0, denoted as base bands B1, B2, B3, B4 (FIG. 7). Base bands are replicated with replication vector t. Oblique base bands B1, B2, B3, B4 are by construction exact replicates of base band B0. The gray parallelograms located respectively in bands B1, B2, B3, B4 (FIG. 7) are therefore exact replicates of the base parallelogram P0 located in band B0. The revealing line grating (revealing lines L0, L1, L2, L3, L4, FIG. 7), superposed on top of the base layer samples the replicated base bands and produces a moiré image (FIG. 3). The intersections of the revealing lines (sampling lines) with replica of base band parallelogram P0, i.e. the sampled line segments l1, l2, l3, l4 are identical to the sampled line segments l1′, l2′, l3′, l4′ within base band parallelogram P0. We observe therefore a linear transformation mapping base band parallelogram P0 to moiré parallelogram P0′. The transformation depends on the relative angle θ between base bands and revealing lines, on the base band replication vector t, and on the revealing line period Tr (FIG. 7). The observed linear transformation also applies to all other base band parallelograms which are horizontal neighbors of base band parallelogram P0 and which form a horizontal band H0 parallel to the revealing lines. Successive horizontal bands are labelled H0, H1, H2, H3 (FIG. 8). Base band parallelograms at the intersection of oblique base band u and horizontal band v are now denominated Pu,v. Neighboring parallelograms within a horizontal band [ . . . ,P1,0, P0,0, P−1,0, . . . ] are mapped to horizontal moiré neighbor parallelograms [ . . . , P1,0′, P0,0′, P−1,0′, . . . ]. Neighboring parallelograms within an oblique base band [ . . . , P0,0, P0,1, . . . ] are mapped to oblique moiré neighbor parallelograms [ . . . , P0,0′, P0,1′, . . . ] Therefore, horizontal base bands H0, H1 are mapped onto horizontal moiré bands H0′, H1′ and oblique base bands B0, B1 are mapped onto oblique moiré bands B0′, B1′ (FIG. 10). Since base band parallelograms Pi,i are replica, corresponding moiré parallelograms Pi,i′ are also replica. When moving the revealing line grating down with a vertical translation of one period Tr, the moiré parallelograms Pu,v′ move to the position of the moiré parallelograms Pu+1,v+1′ (e.g. in FIG. 8, parallelogram P0,0′ moves to the position of parallelogram P1,1′). Let us establish the parameters of the linear transformation mapping base band parallelograms to moiré parallelograms. According to FIG. 9, points A and B of the base band parallelogram remain fix points and point G of the base band parallelogram P0,0 is mapped into point H of the moiré parallelogram P0,0′. The coordinates of point H are given by the intersection of revealing line L1 and the upper boundary of oblique base band B0. One obtains the coordinates of point G by subtracting from the coordinates of point H the replication vector t=(tx,ty). We obtain H=(Tr/tan θ,Tr) and G=(Tr/tan θ−tx,Tr−ty) (7) With B as fix point, i.e. (λ,0)->(λ,0), and with G->H, we obtain the linear transformation mapping base band parallelograms to moiré parallelograms [ x ′ y ′ ] = [ p q r s ] [ x y ] = [ 1 t x T r - t y 0 T r T r - t y ] [ x y ] ( 8 ) Interestingly, with a constant replication vector t, the linear transformation parameters remain constant when modifying angle θ between the base band and the revealing line grating. However, the orientation φ of the moiré parallelogram depends on θ. The moiré parallelogram angle can be derived from line segment {overscore (BH)}, where point B has the coordinates (λ,0) and where λ=(ty/tan θ)−tx. With point H given by Eq. (7), we obtain for the moiré parallelogram orientation φ tan ϕ = T r T r tan θ - λ ( 9 ) One can easily verify that indeed, the slope of the moiré parallelogram obtained by the proposed linear transformation between base layer and moiré layer is identical to the slope of the moiré line described by its indicial equation (6). This can be explained by considering that moiré lines are a special case of band moiré images. If we replace the oblique base band layer with a line grating of the same orientation, period and phase, we obtain within the oblique moiré parallelogram bands the corresponding moiré lines. Expressed as a function of its oblique base band width Tb, with λ=Tb/sin θ, the moiré parallelogram orientation tan ϕ = T r · sin θ T r · cos θ - T b ( 10 ) is identical to the familiar moiré line orientation formula developed according to geometric considerations by Tollenaar (see D. Tollenaar, Moiré-Interferentieverschijnselen bij rasterdruk, Amsterdam Instituut voor Grafische Technick, 1945, English translation: Moiré in halftone printing interference phenomena, published in 1964, reprinted in Indebetouw G. Czarnek R. (Eds.). 618-633, Selected Papers on Optical Moiré and Applications, SPIE Milestone Series, Vol. MS64, SPIE Press, 1992, hereinafter referenced as [Tollenaar 45]). Since both the oblique and the horizontal moiré parallelogram bands are replica (FIG. 8), let us deduce the moiré band replication vector pm. Since base bands are replicated by replication vector t=(tx,ty) and since there is a linear mapping between base band parallelogram P0,0 and moiré parallelogram P0,0′, whose diagonal is the moiré band replication vector pm (FIG. 9), by mapping point (tx,ty) according to the linear transformation given by the system of equations (6), we obtain replication vector pm p m = ( t x + t y · t x T r - t y , t y · T r T r - t y ) = T r T r - t y · t ( 11 ) The orientation of replication vector pm gives the angle along which the moiré band image travels when displacing the horizontal revealing layer on top of the base layer. This moiré band replication vector is independent of the oblique base band orientation, i.e. one may, for the same base band replication vector t=(tx,ty) conceive different oblique base bands yielding the same moiré band replication vector. However, differently oriented oblique base bands will yield differently oriented oblique moiré bands. Corresponding moiré parallelograms will be different, but they will all have replication vector pm as their diagonal. Again, it is possible to verify that in the special case when the oblique base band layer is replaced by a line grating having the same geometric layout, the moiré bands become moiré lines and their respective period Tm (distance between two moiré lines, see FIG. 2B) can be deduced from moiré band replication vector pm. For this purpose, we carry out the dot product between replication vector pm and a unit vector perpendicular to the moiré lines who have the orientation φ (Eq. 9). With tx=(ty/tan θ)−(Tb/sin θ), and we obtain the well known formula for the moiré line period [Tollenaar 45]). T m = T b · T r T b 2 + T r 2 - 2 · T b · T r · cos θ ( 12 ) When rotating either the base band layer or the revealing layer, we modify angle θ and the linear transformation changes accordingly (Eq. 6). When translating the base band layer or revealing layer, we just modify the origin of the coordinate system. Up to a translation, the band moiré patterns remain identical. In the special case where the band grating (base layer) and the revealing layer have the same orientation, i.e. tx=0 and θ=0, according to Eq. (10), the moiré patterns are simply a vertically scaled version of the patterns embedded in the replicated base bands, with a vertical scaling factor of Tr/(Tr−ty)=1(1−ty/Tr). In that case, the width Tb of the base band grating is equal to the vertical component ty of the replication vector t. Synthesis of Rectilinear Band Moiré Images By considering the revealing line grating as a sampling line array, we were able to define the linear transformation between the base layer and the moiré image. The base layer is formed by an image laid out within a single base band replicated with vector t so as to cover the complete base layer space. In order to better understand the various moiré image design alternatives, let us try to create a text message within the base layer according to different layout alternatives. One may for example conceive vertically compressed microtext (or graphical elements) running along the oblique base bands at orientation θ (FIG. 10, left). In the moiré image, the corresponding linearly transformed enlarged microtext will then run along the oblique moiré bands at orientation φ (FIG. 10, right). The microtext's vertical orientation can also be chosen. With equation (9) expressing the relationship between orientations within the base band layer and orientations within the moiré image layer, one may compute the vertical bar orientation (angle θv of the vertical bar of letter “L” in FIG. 10, left) of the microtext which in the moiré image yields an upright text, i.e. a text whose vertical orientation (angle φv=φ+90°) is perpendicular to its baseline (FIG. 10, right). We first express θυ as a function of φυ, replace φυ by φ+90°, and finally express φ as a function of θ. We obtain the microtext's vertical orientation θυ, yielding an upright text in the moiré image cot θ v = 1 λ T r - cot θ + λ T r ( 13 ) Clearly, the orientation of the revealed moiré text baseline (angle φ) is given by the orientation of the oblique band (angle θ). The height of the characters depends on the oblique base band base λ or, equivalently, on its width Tb. The moiré band repetition vector pm which defines how the moiré image is translated when moving the revealing layer up and down, depends according to Eq. (11) on replication vector t=(tx,ty). Once the moiré text baseline orientation θ and oblique band base λ are chosen, one may still modify replication vector t by moving its head along the oblique base band border. By choosing a vertical component ty closer to Tr, the vertical enlargement factor s becomes larger according to Eq. (8) and the moiré image becomes higher, i.e. the text becomes more elongated. Alternatively, instead of designing the microtext within the oblique base bands, one may design microtext within a horizontal base band (FIG. 11) whose height is given by the vertical component ty of base band replication vector t=(tx,ty). By replicating this horizontal base band with replication vector t, we populate the base layer. The vertical orientation of the microtext can be freely chosen. It defines the layout of the corresponding oblique bands and therefore, the vertical orientation φ of the revealed moiré text image (linearly transformed enlarged microtext). The selected replication vector t defines the vertical size of the moiré band H0′ (FIG. 11), i.e. the vertical extension of the revealed moiré text image and its displacement direction pm when the revealing layer moves on top of the base layer (Eq. 11). The choice of the revealing line period Tr depends on the base layer resolution. Generally the period Tr of the revealing line grating is between 5% to 10% smaller or larger than the horizontal base band layer width ty. Considering equation (8), factor s=Tr/(Tr−ty) defines the vertical enlargement between the image located within a horizontal base band (H0 in FIG. 11) and the moiré image located within the corresponding moiré horizontal band H0′. The horizontal base band width ty should offer enough resolution to sample the vertically compressed text or graphical design (vertical compression factor: s). At 1200 dpi, a horizontal base band width of half a millimeter corresponds to 24 pixels. This is enough for displaying text or line graphics. Therefore, at a resolution between 1200 dpi and 600 dpi, we generally select a revealing line grating period between one half to one millimeter. The aperture of the revealing layer, i.e. the width of its transparent lines is between 10% to 15% of its period Tr. The creation of moiré images does not necessarily need a sophisticated computer-aided design system. Let us illustrate the moiré image creation procedure in the case of a microtext laid out within a horizontal base band. One may simply start by defining the period Tr of the revealing layer. Then one creates the desired “moiré” image within a horizontal parallelogram, whose sides define the orientation φ of the oblique moiré band borders Bi′ (FIG. 10). The horizontal parallelogram height defines the vertical size of the moiré band H0′, i.e. the vertical component of replication vector pm and therefore according to Eq. (11) the vertical component ty of replication vector t. One needs then to linearly transform the horizontal moiré image parallelogram in order to fit it within a horizontal band of height ty. This “flattening” operation has one degree of freedom, i.e. point F (FIG. 9) may be freely mapped to a point D located at the top border of the horizontal base band. The mapping between point F and point D yields the value of λ and the horizontal component tx of replication vector t. By modifying the position of point D along the top border of the horizontal base band, one modifies the horizontal component tx of vector t and therefore the orientation pm along which the moiré parallelogram moves when translating the revealing layer on top of the base layer (FIG. 11). Examples of Rectilinear Moiré Images We first consider the simple text strings “EPFL”, “VALID” and “CARD”. Each text string has a specific layout and a specific replication vector t. All distance values are given in pixels at 1200 dpi. “EPFL” is laid out within an oblique band of orientation θ=−1.8°, tx=−15.65, ty=43. “VALID” and “CARD” are each laid out within a horizontal band, with respective replication vectors (tx=9.64, ty=36) and (tx=11.25, ty=42) and respective character verticals at orientations θ=162.7° and θ=14.92° (FIG. 12A). The revealing layer has a period Tr=39 (FIG. 12B, top right). The corresponding base layers superposed with the single revealing layer yield a moiré image composed of 3 differently oriented text pieces travelling up or down along different directions at different relative speeds (FIG. 12C and FIG. 12D). FIG. 12D shows that a translation of the revealing layer on top of the base layer (or vice-versa) yields, up to a vertical translation, the same band moiré image. When the revealing layer moves vertically by one period, the moire bands also move by one period along their displacement orientation given by vector pm (Eq. 11). With a revealing layer displacement speed of u revealing lines per second perpendicular to the revealing lines, the moiré displacement speed vector is therefore u·pm per second. According to Eq. 11 the speed amplification a between revealing layer and moire band image displacement speeds is a=Tr(Tr−ty). As an example, we show a dynamic design (FIG. 13) inspired by the US flag, where the three superposed independent base band gratings (FIG. 13A) generate upon superposition with the revealing layer (FIG. 13B) corresponding moiré image components moving according to their specific relative speeds and orientations (FIGS. 13C and 13D). When two layers have their patterns superposed one on top of the other, we either give priority to one layer (e.g. the USA pattern has priority over the red stripes) or simply superpose the two layers (stars and red stripes). FIG. 14 shows the three base layers and an enlargement of the corresponding base bands (the vertical enlargement factor is twice the horizontal enlargement factor). Note that when the revealing layer period Tr is smaller than the horizontal base band width ty, we obtain according to Eq. (8) a negative vertical enlargement factor s, i.e. a mirrored moiré image (see “USA” base band pattern in FIG. 14). In such cases, base band patterns need to be vertically mirrored to produce a non-mirrored moiré image Curvilinear Band Moirés In addition to periodic band moiré images, one may also create interesting curvilinear band moiré images. It is known from the Fourier analysis of geometrically transformed periodic line gratings [Amidror98] that the moiré generated by the superposition of two geometrically transformed periodic line gratings is a geometric transformation of the moiré formed between the original periodic line gratings. This result is however limited to a base layer formed by a periodic profile line grating and cannot be simply transposed to base layer formed by a band grating. In the next section “Model for the layout of geometrically transformed moiré images”, we disclose the part of the band moiré image layout model which enables computing the layout of moiré images whose base and revealing layers are geometrically transformed. FIGS. 15A, 15B, 16A and 16B give an example of a curvilinear base band grating incorporating the words “VALID OFFICIAL DOCUMENT” revealed by a curvilinear line grating. The curvilinear base band layer (FIG. 15B) as well as the curvilinear revealing line grating (FIG. 16B) in the transformed space xt,yt are obtained from the corresponding rectilinear gratings in the (x,y) original space by the transformation x=g1(xt,yt)=h1(xt,yt), y=g2(xt,yt)=h2(xt,yt) x = h 1 ( x t , y t ) = atan ( x t - c x , y t - c y ) 2 · π · w x y = h 2 ( x t , y t ) = c 1 · ( x t - c x ) 2 + ( y t - c y ) 2 ( 14 ) where (cx,cy) gives the center point in the transformed coordinate space, wx gives the width of the original base layer and c1 is a constant radial scaling factor. Note that the transformations yielding circular gratings may easily be modified to yield elliptic gratings by expressing h2 for example as y = h 2 ( x t , y t ) = c 1 · ( x t - c x a ) 2 + ( y t - c y b ) 2 where a and b are freely chosen constants. To generate the curvilinear base band layer rb(xt,yt), the transformed space within which the curvilinear base band grating is located is traversed pixel by pixel and scanline by scanline. At each pixel (xt,yt), the corresponding position (x,y)=(h1(xt,yt),h2(xt,yt)) in the original rectilinear base band layer is found and its intensity (possibly obtained by interpolation of neighbouring pixels) is assigned to the current curvilinear base band layer pixel rb(xt,yt). As an example, FIG. 15A gives a reference original moiré image in the original coordinate space, from which the original rectilinear base band layer is derived. FIG. 15B gives the corresponding curvilinear base band layer in the transformed space and FIG. 16B the curvilinear revealing line grating in the transformed space. The curvilinear line grating can be reproduced on a transparent support. When placing the curvilinear revealing line grating on top of the curvilinear base band layer (FIG. 15B) at the exact superposition position, i.e. with the coordinate system of the base layer located exactly on top of the coordinate system of the revealing layer, the revealed moiré image shown in FIG. 16A is a circular transformation of the original moire image, i.e. the moire image formed by the superposition of the original non-transformed rectilinear base and revealing layers. When the base layer and the revealing layer are not exactly superposed at the correct relative positions and orientation, the moiré image is still visible, but deformed. By moving and rotating the revealing layer on top of the base layer, one reaches easily the exact superposition position, where the moiré image is a circularly laid out text message (FIG. 16A). Model for the Layout of Geometrically Transformed Moiré Images In this section, we describe the geometric transformation that a moiré image undergoes, when its base band grating and its revealing line grating are subject to a geometric transformation. We then derive conditions and equations of the geometric transformations to be applied either to the rectilinear base band grating and/or to the revealing line grating in order to obtain a desired geometric moire image transformation. Starting with a rectilinear base band grating and a rectilinear revealing line grating, one may apply to them either the same or different non-linear geometric transformations. The curvilinear band moiré image we obtain is a transformation of the original band moiré image obtained by superposing the rectilinear base band and revealing layers. We derive the geometric transformation which gives the mapping between the resulting curvilinear band moiré image and the original rectilinear band moiré image. This mapping completely defines the layout of the curvilinear band moiré image. The key element for deriving the transformation between curvilinear and original moiré images is the determination of parameters within the moiré image, which remain invariant under the layer transformations, i.e. the geometric transformation of base and revealing layers. One parameter remaining invariant is the index k of the moiré parallelogram oblique border lines (FIG. 17A), which correspond to the moiré lines shown in FIG. 2B. The curved (transformed) moiré parallelograms are given by the intersections of curved base band borders and curved revealing lines (FIG. 17B). According to the indicial approach, we may describe any point within the base layer space or respectively within the revealing layer space as being located on one oblique base band line of index n (n being a real number) or respectively on one revealing grating line of index m (m being a real number). Clearly, under a geometric transformation of their respective layers, indices n and m remain constant. The intersection between the family of oblique base band lines of index n and of revealing grating lines of index m yields the family of moiré image lines of index k=n−m (k being a real number), both before applying the geometric transformations and after applying these transformations. Eq. (4) gives the family of moiré image lines parallel to the borders of the moiré parallelogram before applying the geometric transformations. Let us define the geometric transformation between transformed base layer space (xt,yt) and original base layer space (x,y) by x=h1(xt,yt); y=h2(xt,yt) (15) and the geometric transformation between transformed revealing layer space (xt,yt) and original revealing layer space (x,y) by y=g2(xt,yt) (16) Note that any superposition of original base and revealing layers can be rotated so as to obtain a horizontal revealing layer, whose line family equation depends only on the y-coordinate. The transformation from transformed space to original space comprises therefore only the single function y=g2(xt,yt). We can insert these geometric transformations into respectively the oblique line equation (2) and the revealing line equation (3), and with equation (5), we obtain the implicit equation of the moiré lines in the transformed space according to their indices k. n = h 2 ( x t , y t ) - h 1 ( x t , y t ) · tan θ λ · tan θ ; m = g 2 ( x t , y t ) T r k = n - m = h 2 ( x t , y t ) · T r - h 1 ( x t , y t ) · T r · tan θ - g 2 ( x t , y t ) · λ · tan θ λ · T r · tan θ ( 17 ) Since the moiré line indices k are the same in the original (Eq. 5) and in the transformed spaces (Eq. 17), by equating them and bringing all terms into the same side of the equation, we obtain an implicit equation establishing a relationship between transformed and original moiré space coordinates having the form Fk(xt,yt,x,y)=0. Fk(xt,yt,x,y)=h2(xt,yt)·Tr−h1(xt,yt)·Tr·tan θ−g2(xt,yt)·λ·tan θ+x·Tr·tan θ+y·(λ·tan θ−Tr)=0 (18) To completely specify the mapping between each point of the transformed moiré space and each point of the original moiré space, we need an additional implicit equation relating transformed and original moiré image layer coordinates. We observe that replicating oblique base bands with the replication vector t is identical to replicating horizontal base bands with replication vector t (FIG. 8). We can therefore concentrate our attention on the moiré produced by superposing the horizontal revealing line grating (FIG. 18, continuous horizontal lines) and the horizontal base bands (FIG. 18, horizontal base bands separated by dashed horizontal lines). Clearly, base band parallelogram Pλt with base λ and with replication vector t as parallelogram sides is mapped by the linear transformation (Eq. 8) into the moiré parallelogram Pλt′ having the same base λ and parallelogram sides given by moiré band replication vector pm. Note that successive vertically adjacent replica of moiré parallelogram Pλt′ are mapped by the linear transformation into identical replica of the base band parallelogram Pλt Therefore, within the moiré image, each infinite line of orientation pm, called d-line is only composed of replica of a single line segment db parallel to t within the base band. This is true, independently of the value of the revealing grating period Tr. With a given horizontal base band (e.g. FIG. 18, 181) of width ty and a base band replication vector t forming an angle β with the horizontal, we can generate an infinite number of oblique base band layouts by rotating oblique base band borders (e.g. oblique base band border 182) around their intersection points with horizontal base band border 183. The smaller the difference between angles θ and β, the smaller the base segment λ (FIG. 18). Oblique base bands oriented according to vector t, i.e. with an angle θ=β, become infinitely thin. At this orientation, an infinite number of oblique base band borders fall into a single d-line 185. This d-line becomes therefore the moiré line located at the intersections between oblique base band borders and revealing lines 184. This moiré line (d-line 185) remains identical when the oblique base band borders are intersected with a geometrically transformed revealing line layer. Therefore, d-lines within the moiré image space remain invariant under geometric transformation of the revealing layer. For example, when superposing the base layer of FIG. 12A with the revealing layer of FIG. 12B and applying to the revealing layer a rotation, a translation or any other transformation, points of the original moiré image move only along their respective d-lines. Under geometric transformation of the base layer, straight d-lines are transformed into curved d-lines. In the moiré image space, a point located on a straight d-line will remain, after application of a geometric transformation to the revealing layer and of a (generally different) geometric transformation to the base layer, on the corresponding transformed curved d-line. By numbering the d-lines according to d-parallelogram borders (FIG. 18), we can associate every point within the moiré image to a d-line index (real number). Since the d-line indices are the same in the original and in the transformed moiré image, we can equate them and establish an implicit equation of the form Fd(xt,yt,x,y)=0. The d-line family equations in the original and transformed spaces are respectively y=x·tan β+d·λ·tan θ (19) and h2(xt,yt)=h1(xt,yt)·tan β+d·λ·tan θ (20) where β is the angle of replication vector t with the horizontal and where d is the d-line index. If we extract the line index d from equation (19) and also from equation (20), by equating them, we obtain the following implicit equation Fd(xt,yt,x,y)=h2(xt,yt)−h1(xt,yt)·tan β+x·tan β−y=0 (21) We can now solve for x and y the equation system formed by Fk(xt,yt,x,y)=0 (Eq. 18) and Fd(xt,yt,x,y)=0 (Eq. 21) and obtain, by replacing respectively in equations (18) and (21) λ=ty cot θ−tx tan β=ty/tx (22) the transformation (m1(xt,yt),m2(xt,yt)) of the moiré image from transformed moiré space to original moiré space x = m 1 ( x t , y t ) = h 1 ( x t , y t ) + ( h 2 ( x t , y t ) - g 2 ( x t , y t ) ) · t x T r - t y y = m 2 ( x t , y t ) = h 2 ( x t , y t ) · T r T r - t y - g 2 ( x t , y t ) · t y T r - t y ( 23 ) The transformation (m1(xt,yt),m2(xt,yt)) is independent of the oblique base band orientation. Relevant parameters are the revealing layer line period Tr and the base band replication vector t=(tx,ty). Equations (23) define the transformation M: (xt,yt)->(x,y) of the moiré image from transformed moiré space to original moiré space as a function of the transformation of the base band grating H: (xt,yt)->(x,y), and of the transformation of the revealing line grating G: (xt,yt)->(x,y) from transformed space to the original space. In the present formulation, according to Eq.(23), M(xt,yt)=(m1(xt,yt,m2(xt,yt)), H(xt,yt)=(h1(xt,yt,h2(xt,yt)), and G(xt,yt)=(x,g2(xt,yt), where x takes all real values. However, different formula equivalent to equation (23) may be associated to the transformations M, H, and G Equations (23) show that when the transformations of base layer and revealing layer are identical i.e. (h2(xt,yt)=g2(xt,yt), the moiré transformation is identical to the transformation of the base layer, i.e. m1(xt,yt)=h1(xt,yt) and m2(xt,yt)=h2(xt,yt). This is confirmed by FIG. 16A, which shows that the moiré obtained from the superposition of the circularly transformed base and revealing layers (respectively FIGS. 15B and 16B) is also circular, i.e. the original moiré text laid out along horizontal lines becomes, due to the resulting circular moiré transformation expressed by m1(xt,yt) and m2(xt,yt), laid out in a circular manner. Having obtained the full expression for the induced moiré transformation when transforming base and revealing layers, we can select a given moiré transformation i.e. m1(xt,yt) and m2(xt,yt), select either the revealing layer transformation g2(xt,yt) or the base layer transformation given by h1(xt,yt),h2(xt,yt) and derive, by solving equation system (23) the other layer transformation. The easiest way to proceed is to freely define the moiré transformation m1(xt,yt) and m2(xt,yt) and the revealing layer transformation g2(xt,yt), and then deduce the base layer transformation given by h1(xt,yt) and h2(xt,yt). h 1 ( x t , y t ) = ( g 2 ( x t , y t ) - m 2 ( x t , y t ) ) · t x T r + m 1 ( x t , y t ) h 2 ( x t , y t ) = g 2 ( x t , y t ) · t y T r + m 2 ( x t , y t ) · T r - t y T r ( 24 ) Equations (24) express the transformation H of the base band grating layer from transformed space to original space as a function of the transformations M and G transforming respectively the band moiré image and the revealing line grating from transformed space to original space. The transformations M, G and H, embodied by the set of equations (23) or equivalently, by the set of equations (24), form a band moiré image layout model completely describing the relations between the layout of the base band grating layer, the layout of the revealing line grating layer and the layout of the resulting band moiré image layer. The layout of two of the layers may be freely specified and the layout of the third layer may then be computed thanks to this band moiré image layout model. In some of the examples given in the next section, we freely choose a revealing layer transformation g2(xt,yt), and require as band moiré image transformation the identity transformation, i.e. m1(xt,yt)=xt and m2(xt,yt)=yt. This allows us to generate the same band moiré image before and after the layer transformations. We obtain periodic band moiré images, despite the fact that both the base layer and the revealing layer are curved, i.e. non-periodic. We then show examples, where we freely chose the revealing layer and require the band moiré image transformation to be a known geometric transformation, for example a transformation yielding circularly laid out band moiré patterns. Moiré Design Variants with Curvilinear Base and Revealing Layers Let us now apply the knowledge disclosed in the previous section and create various examples of rectilinear and curvilinear moirés images with at least one the base or revealing layers being curvilinear. EXAMPLE A Rectilinear Moiré Image and a Cosinusoidal Revealing Layer In order to generate a rectilinear moiré image with a cosinusoidal revealing layer, we transform the original base and revealing layer shown in FIGS. 12A and 12B. We want the superposition of the transformed base and revealing layer to yield the same rectilinear moiré image (FIG. 19C) as the moiré image formed by the original rectilinear layers (FIG. 12C), i.e. m1(xt,yt)=xt and m2(xt,yt)=yt. We define the revealing layer transformation g2(xt,yt)=yt+c1 cos(2π(xt+c3)/c2) (25) with c1, c2 and c3 representing constants and deduce from equations (21) the geometric transformation to be applied to the base layer, i.e. h1(xt,yt)=xt+c1 cos(2π(xt+c3)/c2)(tx/Tr) h2(xt,yt)=yt+c1 cos(2π(xt+c3)/c2)(tx/Tr) (26) We can move the revealing layer (FIG. 19B) up and down on top of the base layer (FIG. 19A), and the moiré image shapes (FIG. 19C) will simply be translated (FIG. 19D) without incurring deformations. We can verify that such a vertical translation does not, up to a translation, modify the resulting moiré image (presently an identity) by inserting into equations (23) the transformations g2 (Eq. 25) and h1, h2 (Eqs. 26) and by replacing in g2(xt,yt) coordinate yt by its translated version yt+Δyt. We obtain m1(xt,yt)=xt−txΔyt/(Tr−ty) and m2(xt,yt)=yt−tyΔyt/(Tr−ty), (27) i.e. the original moiré image is simply translated according to vector t=(tx,ty), scaled by the relative vertical displacement Δyt/(Tr−ty). EXAMPLE B Rectilinear Moiré Image and a Circular Revealing Layer We introduce a revealing layer transformation yielding a perfectly circular revealing line grating (FIG. 20B) g2(xt,yt)=c1√{square root over ((xt−cx)2+(yt−cy)2)} (28) where cx and cy are constants giving the center of the circular grating and c1 is a scaling constant. In order to obtain a rectilinear moiré image, we define the base layer transformations according to Eq. 24 h 1 ( x t , y t ) = x t + ( c 1 ( x t - c x ) 2 + ( y t - c y ) 2 - y t ) · t x T r h 2 ( x t , y t ) = c 1 ( x t - c x ) 2 + ( y t - c y ) 2 · t y T r + y t · T r - t y T r ( 29 ) The resulting base layer is shown in FIG. 20A. FIG. 20C, shows that the superposition of a strongly curved base band grating and of a perfectly circular revealing line grating yields the original rectilinear moiré image. However, as shown in FIG. 20D, a small displacement of the revealing layer yields a clearly visible deformation (i.e. distortion) of the resulting band moiré image. Note that by varying parameters c1, cx and cy one may create a large number of variants of the same transformation. Furthermore, by replacing in the preceding equations (28) and (29) beneath the square root xt−cx with (xt−cx)/a and yt−cy by (yt−cy)/b, where a and b are freely chosen constants, one may extend this example to concentric elliptic revealing line gratings. Examples A and B show that rectilinear moiré images can be generated with curvilinear base and revealing layers. Let us now show examples where thanks to the band moiré image layout model, we can obtain curvilinear moiré images which have the same layout as predefined reference moiré images. EXAMPLE C Circular Band Moiré Image and Rectilinear Revealing Layer In the present example, we choose a circular moiré image and also freely choose the revealing layer layout. The desired reference circular moiré image layout is given by the transformation mapping from transformed moiré space back into the original moiré space, i.e. x = m 1 ( x t , y t ) = π - atan ( y t - c y , x t - c x ) 2 · π · w x y = m 2 ( x t , y t ) = c m ( x t - c x ) 2 + ( y t - c y ) 2 ( 30 ) where constant cm expresses a scaling factor, constants cx and cy give the center of the circular moiré image layout in the transformed moiré space, wx expresses the width of the original rectilinear reference band moiré image and function a tan(y,x) returns the angle α of a radial line of slope y/x, with the returned angle a in the range (−π<=α<=π). The corresponding desired reference circular moiré image is shown in FIG. 21A. We take as revealing layer a rectilinear layout identical to the original rectilinear revealing layer, i.e. g2(xt,yt)=yt. This rectilinear revealing layer is shown in FIG. 22B. By inserting the curvilinear moiré image layout equations (30) and the curvilinear revealing layer layout equation g2(xt,yt)=yt into the band moire layout model equations (24), one obtains the deduced curvilinear base layer layout equations h 1 ( x t , y t ) = ( y t - c m ( x t - c x ) 2 + ( y t - c y ) 2 ) · t x T r + π - atan ( y t - c y , x t - c x ) 2 · π · w x h 2 ( x t , y t ) = c m ( x t - c x ) 2 + ( y t - c y ) 2 · T r - t y T r + y t · t y T r ( 31 ) These curvilinear base layer layout equations express the geometric transformation from transformed base layer space to the original base layer space. The corresponding curvilinear base layer in the transformed space is shown in FIG. 22A. The resulting moiré image formed by the superposition of the base layer (FIG. 22A) and of the revealing layer (FIG. 22B) is shown in FIG. 21B. When the revealing layer (FIG. 22B) is moved over the base layer (FIG. 22A), the corresponding circular moiré image patterns move radially and change their shape correspondingly. In the present example, the text letter width becomes larger or smaller, depending if the letters move respectively towards the exterior or the interior of the circular moiré image. In a similar manner as in example B, the present example may be easily generalized to elliptic band moiré images. EXAMPLE D Curvilinear Moiré Image and Cosinusoidal Revealing Layer Let us now take a curvilinear revealing layer and still generate the same desired curvilinear moiré image as in the previous example (reference band moiré image shown in FIG. 21A). As example, we take as curvilinear revealing layer a cosinusoidal layer whose layout is obtained from the rectilinear revealing layer by a cosinusoidal transformation g2(xt,yt)=yt+c1 cos(2πxt/c2) (32) where constants c1 and c2 give respectively the amplitude and period of the cosinusoidal transformation. The corresponding cosinusoidal revealing layer is shown in FIG. 23A. By inserting the curvilinear moiré image layout equations (30) and the curvilinear revealing layer layout equation (32) into the band moire layout model equations (24), one obtains the deduced curvilinear base layer layout equations h 1 ( x t , y t ) = ( y t + c 1 cos ( 2 π x t c 2 ) - c m ( x t - c x ) 2 + ( y t - c y ) 2 ) · t x T r + π - atan ( y t - c y , x t - c x ) 2 · π · w x h 2 ( x t , y t ) = c m ( x t - c x ) 2 + ( y t - c y ) 2 · T r - t y T r + ( y t + c 1 cos ( 2 π x t c 2 ) ) · t y T r ( 33 ) These curvilinear base layer layout equations express the geometric transformation from the transformed base layer space to the original base layer space. The corresponding curvilinear base layer is shown in FIG. 23B. The superposition of the curvilinear base layer (FIG. 23B) and curvilinear revealing layer (FIG. 23A) is shown in FIG. 24. When the revealing layer (FIG. 23A) is moved vertically over the base layer (FIG. 23B), the corresponding circular moiré image patterns move radially and change their shape correspondingly, as in example C. However, when the revealing layer (FIG. 23A) is moved horizontally over the base layer (FIG. 23B), the circular moiré patterns become strongly deformed. After a horizontal displacement equal to the period c2 of the cosinusoidal revealing layer transformation, the circular moiré patterns have again the same layout and appearance as in the initial base and revealing layer superposition, i.e the deformation fades away as the revealing layer reaches a horizontal position close to an integer multiple of period c2. This yields a moiré image which deforms itself periodically upon horizontal displacement of the revealing layer on top of the base layer. Note that the dynamicity of the band moiré image patterns relies on the types of geometric transformations applied to generate the base and revealing layer in the transformed space and not, as in U.S. patent application Ser. No. 10/270,546 (Hersch, Chosson) on variations of the shapes embedded within the base band layer. The present example may also easily be generalized to elliptic band moiré images. EXAMPLE E Circularly Transformed Moiré Image Generated with a Spiral Shaped Revealing Layer Let us show a further example relying on the band moiré layout model in order to obtain a circularly transformed moiré image. We choose as revealing layer layout a spiral shaped revealing layer. The desired reference circular moiré image layout is given by the geometric transformation described by Eqs. (30) which transform from transformed moiré space back into the original moiré space. The spiral shaped revealing line grating layout (FIG. 25) comprising multiple spirals is expressed by the following transformation mapping from transformed space to original space y = g 2 ( x t , y t ) = c m ( x t - c x ) 2 + ( y t - c y ) 2 + π + atan ( y t - c y , x t - c x ) 2 · π T r · n s ( 34 ) where cx and cy are constants giving the center of the spiral line grating, cm is the scaling factor (same as in Eq. 30), Tr is the revealing line grating period in the original space and nS is the number of spirals leaving the center of the spiral line grating. By inserting the curvilinear moiré image layout equations (30) and the spiral shaped revealing layer layout equation (34) into the band moire layout model equations (24), one obtains the deduced the curvilinear base layer layout equations h 1 ( x t , y t ) = π + atan ( y t - c y , x t - c x ) 2 · π · ( w x + t x · n s ) h 2 ( x t , y t ) = c m ( x t - c x ) 2 + ( y t - c y ) 2 + π + atan ( y t - c y , x t - c x ) 2 · π · t y · n s . ( 35 ) These curvilinear base layer layout equations express the geometric transformation from the transformed base layer space to the original base layer space. They completely define the layout of the base band grating layer (FIG. 26) which, when superposed with the revealing layer (FIG. 25) whose layout is defined by Eq. (34) yield a circular band moiré image (FIG. 27), with a layout defined by Eq. (27). FIG. 27 shows the curvilinear moiré image obtained when superposing exactly the origin the coordinate system of the revealing layer on the origin of the coordinate system of the base layer. When rotating the revealing layer on top of the base layer around its center point given by coordinates (cx,cy), a dynamic band moiré image is created with band moiré image patterns moving toward the exterior or the interior of the circular band moiré image, depending if respectively a positive or a negative rotation is applied. For the sake of simplicity, we considered in the preceding examples mainly transformations yielding circular revealing, base or moiré image layers. As described in some of the examples, by inserting into the formula instead of the radius of a circle √{square root over ((xt−cx)2+(yt−cy)2)} the corresponding distance from the center to a point (xt,yt) of an ellipse ( x t - c x a ) 2 + ( y t - c y b ) 2 where a and b are freely chosen constants, the considered concentric circular layers may be extended to form concentric elliptic layers. We therefore call “concentric layouts” both the circular and the elliptic layouts. The previous examples shows that thanks to the band moire layout model, we are able to compute the exact layout of curvilinear base and revealing layers so as to generate a desired rectilinear or curvilinear moiré image of a given predefined layout. Base and Revealing Layers Partitioned into Different Portions Synthesized with Different Pairs of Base and Revealing Layers Transformations One may freely choose the curvilinear revealing layer layout and deduce from a desired rectilinear or curvilinear moiré image layout the corresponding curvilinear base layer layout or vice-versa. Let us denote the base layer and revealing layer geometric transformations producing a desired rectilinear or curvilinear moiré image layout as a “pair of matching geometric transformations” and the corresponding layer layouts in the transformed space as a “pair of matching base and revealing layer layouts”. In order to provide additional security and make counterfeiting even harder, one may partition the desired moiré image into several portions and render each portion with a specific pair of matching geometric transformations. Corresponding portions of both the base layer and the revealing layer will be rendered with different pairs of geometric transformations. For example, we can generate the desired reference circular band moiré image shown in FIG. 21A by specifying two different moiré image portions, each one generated with a different pair of matching geometric transformations. Examples in FIGS. 28A and 28B show respectively the base layer and the revealing layer with different portions created according to different pairs of matching geometric transformations. The image portions at the left and right extremity of the image (base layer 281 and 283, revealing layer 284 and 286) are generated with the matching transformations described in Example D (cosinusoidal revealing layer). The image portion at the center of the image (base layer 282, revealing layer 285) is generated with the matching transformation described in Example C (rectilinear revealing layer). FIG. 29 shows the curvilinear moiré image obtained by superposing the base layer of FIG. 28A and the revealing layer of FIG. 28B. One may verify that thanks to the band moire layout model, despite the partition of the base layer and revealing layer into different portions laid out differently, according to different pairs of matching geometric transformations, the band moiré image induced by the superposition of the partitioned base and revealing layers has the same layout as the desired reference band moiré image. Perspectives Offered by the Band Moiré Layout Model The relationships between geometric transformations applied to the base and revealing layers and the resulting geometric transformation of the band moiré image (see Eqs. (23) and (24)), represent a model for describing the layout of the band moiré image as a function of the layouts of the base band grating and of the revealing line grating. By applying this model one may compute the base and/or the revealing layer layouts, i.e the geometric transformations to be applied to the original rectilinear base and/or revealing layers in order to obtain a reference moiré image layout, i.e. a moiré image layout according to a known geometric transformation applied to the original rectilinear band moiré image. The examples presented in the previous sections represent only a few of the many possible transformations that may be applied to the moire layer, to the base layer and/or to the revealing layer. Many other transformations can be applied, for example transformations which may produce zone plate gratings [Oster 64], hyperbolic sine gratings, or gratings mapped according to conformal transformations. In more general terms, any continuous function of the type f(xt,yt) is a candidate function for the functions g2(xt,yt),h2(xt,yt), and/or m2(xt,yt). Only a more detailed analysis of such candidate functions enables verifying if they are usable in the context of geometric layer transformations, i.e. if they yield, at least for certain constants and within given regions of the transformed space, base bands, revealing lines and moiré bands suitable for document authentication. A catalogue of implicit functions f(xt,yt)=c, where c represents a constant, usable as candidate geometric transformation functions can be found in the book “Handbook and Atlas of Curves”, by Eugene V. Shikin, CRC Press, 1995 or on pages 319-329 of the book “Handbook of Mathematics and Computational Science” by J. W. Harris and H Stocker, published by Springer Verlag in 1998. A library of suitable functions f(xt,yt) with corresponding constant ranges may be established, for example for the transformation (m1(xt,yt),m2(xt,yt)) transforming a band moiré image from transformed space to original space and for the transformation g2(xt,yt) transforming a revealing line grating from transformed space to original space. Once a library of transformation functions is established, which comprises for each transformation corresponding ranges of constants, thousands of different layouts become available for the band moiré image layout, the revealing line grating layout and according to Eq. (24) for the base band layer layout. The very large number of possible geometric transformations for generating curvilinear base band layers and curvilinear revealing line gratings allows to synthesize individualized base and revealing layers, which, only as a specific pair, are able to produce the desired reference band moiré image (e.g. a rectilinear or a curvilinear moiré image) if they are superposed according to specific geometric conditions (relative position and/or relative orientation). One of the layers, e.g. the curvilinear revealing layer may be publicly available (e.g. downloadable from a Web server) and may serve as an authentication means. It would be very difficult to create, without knowledge of the revealing layer's layout (i.e. without knowledge of the geometric transformation mapping it from transformed space to original space) a base layer which would yield in superposition with that revealing layer a rectilinear moiré image. Furthermore, since the base layer and the revealing layer may be divided into many portions each generated according to a different pair of matching geometric transformations, it becomes impossible for potential counterfeiters to resynthesize the base layer without knowing in detail the relevant geometric transformations as well as the constants and positions used to synthesize the base layer. In addition, it is possible to reinforce the security of widely disseminated documents such as banknotes, diploma, entry tickets, travel documents and valuable products by often modifying the parameters which define the geometric layout of the base layer and of its corresponding revealing layer. One may for example have geometric transformations and their associated constants which depend on a security document's issue date or production series number. For example, each series of a document may be mapped onto a different set of geometric layouts, given by different transformations and/or transformation constants. Multichromatic Base Band Patterns The present invention is not limited only to the monochromatic case. It may largely benefit from the use of different colors for producing the patterns located in the bands of the base layer. One may generate colored base bands in the same way as in standard multichromatic printing techniques, where several (usually three or four) halftoned layers of different colors (usually: cyan, magenta, yellow and black) are superposed in order to generate a full-color image by halftoning. By way of example, if one of these halftoned layers is used as a base layer according to the present invention, the band moiré patterns that will be generated with a revealing transparent line grating will closely approximate the color of this base layer. If several different colored layers are used for the base band according to the present invention, they will generate when superposed with a revealing transparent line grating a band moiré pattern approximating the color resulting from the superposition of these different colored layers. Another possible way of using colored bands in the present invention is by using a base layer whose individual bands are composed of patterns comprising sub-elements of different colors. Color images with subelements of different colors printed side by side may be generated according to the multicolor dithering method described in U.S. patent application Ser. No. 09/477,544 filed Jan. 4, 2000 (Ostromoukhov, Hersch) and in the paper “Multi-color and artistic dithering” by V. Ostromoukhov and R. D. Hersch, SIGGRAPH Annual Conference, 1999, pp. 425-432. An important advantage of this method as an anticounterfeiting means is gained from the extreme difficulty in printing perfectly juxtaposed sub-elements of patterns, due to the high required precision in the alignment of the different colors (registration precision). Only the best high-performance security printing equipment which is used for printing security documents such as banknotes is capable of offering such a registration precision. Registration errors which are unavoidable when counterfeiting the document on lower-performance equipment will cause small shifts between the different colored sub-elements of the base layer elements; such registration errors will be largely magnified by the band moiré, and they will significantly corrupt the shape and the color of the band moiré image obtained by the revealing line grating layer. The document protection by microstructure patterns is not limited to documents printed with black-white or standard color inks (cyan, magenta, yellow and possibly black). According to pending U.S. patent application Ser. No. 09/477,544 (Method an apparatus for generating digital halftone images by multi-color dithering, inventors V. Ostromoukhov, R. D. Hersch, filed Jan. 4, 2000), it is possible, with multicolor dithering, to use special inks such as non-standard color inks, inks visible under UV light, metallic inks, fluorescent or iridescent inks (variable color inks) for generating the patterns within the bands of the base layer. In the case of a metallic ink (see U.S. patent application Ser. No. 10/440,355, Hersch, Emmel, Collaud), for example, when seen at a certain viewing angle, the band moiré patterns appear as if they would have been printed with normal inks and at another viewing angle (specular observation angle), due to specular reflection, they appear much more strongly. A similar variation of the appearance of the band moiré patterns can be attained with iridescent inks. Such variations in the appearance of the band moiré patterns completely disappear when the original document is scanned and reproduced or photocopied. Using special inks visible under ultra-violet light (hereinafter called UV inks) for printing the base layer allows to reveal moiré images under UV light, but may either hide them completely or partially under normal viewing conditions. If UV inks which are partly visible under day light are combined with standard inks, for example by applying the multicolor dithering method cited above, photocopiers will not be able to extract the region where the UV ink is applied and therefore potential counterfeiters will not be able to generate the base layer, even with expensive printing equipment (offset). In the resulting forgered document, under UV light, no moiré image will appear. Another advantage of the multichromatic case is obtained when non-standard inks are used to create the pattern in the bands of the base layer. Non-standard inks are often inks whose colors are located out the gamut of standard cyan magenta and yellow inks. Due to the high frequency of the colored patterns located in the bands of the base layer and printed with non-standard inks, standard cyan, magenta, yellow and black reproduction systems will need to halftone the original color thereby destroying the original color patterns. Due to the destruction of the patterns within the bands of the base layer, the revealing layer will not be able to yield the original band moiré patterns. This provides an additional protection against counterfeiting. Embodiments of Base and Revealing Layers The base layer with one or several base band gratings and the revealing layer made of a revealing line grating may be embodied with a variety of technologies. Important embodiments for the base layer are offset printing, ink-jet printing, dye sublimation printing and foil stamping. It should be noted that the layers (the base layer, the revealing layer, or both) may be also obtained by perforation instead of by applying ink. In a typical case, a strong laser beam with a microscopic dot size (say, 50 microns or even less) scans the document pixel by pixel, while being modulated on and off, in order to perforate the substrate in predetermined pixel locations. A revealing line grating may be created for example as partially perforated lines made of perforated segments of length l and unperforated segments of length m, with pairs of perforated and unperforated parts (l,m) repeated over the whole line length. For example, one may choose l= 8/10 mm and m= 2/10 mm. Successive lines may have their perforated segments at the same or at different phases. Different parameters for the values l and m may be chosen for different successive lines in order to ensure a high resistance against tearing attempts. Different laser microperforation systems for security documents have been described, for example, in “Application of laser technology to introduce security features on security documents in order to reduce counterfeiting” by W. Hospel, SPIE Vol. 3314, 1998, pp. 254-259. In yet another category of methods, the layers (the base layer, the revealing layer, or both) may be obtained by a complete or partial removal of matter, for example by laser or chemical etching. To vary the color of band moiré patterns, one may also chose to have the revealing line grating made of a set of colored lines instead of transparent lines (see article by I. Amidror, R. D. Hersch, Quantitative analysis of multichromatic moiré effects in the superposition of coloured periodic layers, Journal of Modern Optics, Vol. 44, No. 5, 1997, 883-899). Although the revealing layer (line grating) will generally be embodied by a film or plastic support incorporating a set of transparent lines, it may also be embodied by a line grating made of cylindric microlenses. Cylindric microlenses offer a higher light intensity compared with corresponding partly transparent line gratings. When the period of the base band layer is small (e.g. less than ⅓ mm), cylindric microlenses as revealing layer may also offer a higher precision. One can also use as revealing layer curvilinear cylindric microlenses. One may also use instead of cylindric microlenses a diffractive device emulating the behavior of cylindric microlenses, in the same manner as it is possible to emulate a microlens array with a diffractive device made of Fresnel Zone Plates (see B. Saleh, M. C. Teich, Fundamentals of Photonics, John Wiley, 1991, p. 116). In the case that the base layer is incorporated into an optically variable surface pattern, such as a diffractive device, the image forming the base layer needs to be further processed to yield for each of its pattern image pixels or at least for its active pixels (e.g. black or white pixels) a relief structure made for example of periodic function profiles (line gratings) having an orientation, a period, a relief and a surface ratio according to the desired incident and diffracted light angles, according to the desired diffracted light intensity and possibly according to the desired variation in color of the diffracted light in respect to the diffracted color of neighbouring areas (see U.S. Pat. No. 5,032,003 inventor Antes and U.S. Pat. No. 4,984,824 Antes and Saxer). This relief structure is reproduced on a master structure used for creating an embossing die. The embossing die is then used to emboss the relief structure incorporating the base layer on the optical device substrate (further information can be found in U.S. Pat. No. 4,761,253 inventor Antes, as well as in the article by J. F. Moser, Document Protection by Optically Variable Graphics (Kinemagram), in Optical Document Security, Ed. R. L. Van Renesse, Artech House, London, 1998, pp. 247-266). It should be noted that in general the base and the revealing layers need not be complete: they may be masked by additional layers or by random shapes. Nevertheless, the moiré patterns will still become apparent. Authentication of Documents with Static and Dynamically Varying Band Moiré Images The present invention presents improved methods for authenticating documents and valuable products, which are based on band moiré patterns produced by base and revealing layers computed according to a band moire layout model. Several embodiments of particular interest are given here by way of example, without limiting the scope of the invention to these particular embodiments. In one embodiment of the present invention, the band moiré image can be visualized by superposing the base layer and the revealing layer which both appear on two different areas of the same document or article (banknote, check, etc.). In addition, the document may incorporate, for comparison purposes, in a third area of the document a reference image showing the band moiré image layout produced when base layer and revealing layer are placed one on top of the other according to a preferred orientation and possibly according to a preferred relative position. Furthermore, the band moiré image can be partitioned into different portions, each corresponding base layer portion and a revealing layer portion being laid out differently according to corresponding pairs of matching geometric transformations. Nevertheless, the band moiré image resulting from the superposition of base and revealing layers should be continuous, i.e. without breaks at the boundaries between band moire image portions and have the same layout as the reference band moiré image. When moving the revealing layer on top of the base layer, the moiré image may remain continuous or on the contrary, one portion of the moiré image may become strongly deformed, possibly in a periodic manner. In a second embodiment of the present invention, only the base layer appears on the document itself, and the revealing layer is superposed on it by a human operator or an apparatus which visually or optically validates the authenticity of the document. For comparison purposes, the reference band moiré image may be represented as an image on the document or on a separate device, for example on the revealing device. As in the first embodiment, the band moiré image can be partitioned into different portions, each corresponding base layer portion and revealing layer portion being laid out differently according to corresponding pairs of matching geometric transformations. And as in the first embodiment, upon moving of one layer on top of the other, different portions of the moiré image may behave differently, by either remaining without deformation or by being deformed. In a further embodiment, document authentication is carried out by observing the dynamic band moiré image variations produced when moving or rotating the revealing layer on top of the base layer (or vice-versa). Thanks to the comprehensive band moiré image layout model, geometric transformations of the base and/or revealing layers may be computed so as to yield given predetermined dynamic moiré image variations, for example no deformation of the band moiré image patterns when moving the revealing layer vertically on top of the base layer and a strong periodic deformation of the band moiré image patterns when moving the revealing layer horizontally on top of the base layer. Examples of dynamic band moiré image variations have been described in the preceding sections. Such dynamic band moiré image variations comprise moiré patterns moving along different orientations and according to different relative speeds, concentrically laid out moiré patterns moving in a radial manner, and moiré patterns which deform themselves periodically upon displacement of the revealing layer on top of the base layer. This enumeration is given only by way of example. Different transformations of the base and/or revealing layers yield different types of dynamic moiré patterns. Any attempt to falsify a document produced in accordance with the present invention by photocopying, by means of a desk-top publishing system, by a photographic process, or by any other counterfeiting method, be it digital or analog, will inevitably influence (even if slightly) the layout, shape or patterns of the base band layer incorporated in the document. Factors which may be responsible for an inaccurate reproduction of the base band layer are the following: use of a transformation mapping from transformed space to original space which is different from the original transformation applied to the authentic document, resampling effects when scanning the base layer, halftoning or dithering effects when reproducing the base layer, and dot gain or ink spreading effects when printing the base layer. Since the band moiré image is very sensitive to any microscopic variations in the base or the revealing layers, any document protected according to the present invention becomes very difficult to counterfeit, and serves as a means to distinguish between a real document and a falsified one. When the base band layer is printed on the document with a standard printing process, high security is offered without requiring additional costs in the document production. Even if the base band layer is imaged into the document by other means, for example by generating the base layer on an optically variable device (e.g. a kinegram) and by embedding this optically variable device into the document or article to be protected, no additional costs incur due to the incorporation of the base band layer into the optically variable device. Authentication of Valuable Products by Dynamically Varying Band Moiré Images In the same way as described in U.S. patent application Ser. No. 10/270,546, various embodiments of the present invention can be also used as security devices for the protection and authentication of industrial packages, such as boxes for pharmaceutics, cosmetics, etc. However, since the base band layer and revealing line layer are computed according to a band moire layout model, their respective layouts can be exactly computed in order to produce a band moiré image with the same layout and appearance as a reference moiré image. Furthermore, the possibility of partitioning the base and revealing layers into portions having different layouts but generating a same band moiré image offers a much stronger protection than the band moiré images produced according to U.S. patent application Ser. No. 10/270,546. In addition, thanks to the band moire layout model, it is possible to create specific dynamic variations of the band moiré images (see section “Authentication of documents with static and dynamically varying band moiré images”), which can serve as an authentication reference. Let us enumerate examples of security documents protected according to the previously disclosed methods. Packages that include a transparent part or a transparent window are very often used for selling a large variety of products, including, for example, audio and video cables, connectors, integrated circuits (e.g flash memories), perfumes, etc., where the transparent part of the package may be also used for authentication and anticounterfeiting of the products, by using a part of the transparent window as the revealing layer (where the base layer is located on the product itself). The base layer and the revealing layer can be also printed on separate security labels or stickers that are affixed or otherwise attached to the product itself or to the package. A few possible embodiments of packages which can be protected by the present invention are illustrated below, and are similar to the examples described in U.S. patent application Ser. No. 09/902,445 (Amidror and Hersch) in FIGS. 17-22. therein. However, since in the present invention, the band moiré images are clearly visible in reflective mode and since the band moiré layout model provides a strong additional protection, the incorporation of base band patterns in the base layer and the use of a line grating as the revealing layer makes the protection of valuable products more effective than with the methods described in U.S. patent application Ser. No. 09/902,445 (Amidror and Hersch) and in U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson). FIG. 30A illustrates schematically an optical disk 391, carrying at least one base layer 392, and its cover (or box) 393 carrying at least one revealing layer (revealing line grating) 394. When the optical disk is located inside its cover (FIG. 39B), a band moiré moire image 395 is generated between one revealing layer and one base layer. While the disk is slowly inserted or taken out of its cover 393, this band moiré image varies dynamically. This dynamically moving band moiré image serves therefore as a reliable authentication means and guarantees that both the disk and its package are indeed authentic (see section “Authentication of documents with static and dynamically varying band moiré images”). In a typical case, the band moiré image may comprise the logo of the company, or any other desired text or symbols, either in black and white or in color. FIG. 31 illustrates schematically a possible embodiment of the present invention for the protection of products that are packed in a box comprising a sliding part 311 and an external cover 312, where at least one element of the moving part, e.g. a product, carries at least one base layer 313, and the external cover 312 carries at least one revealing layer (revealing line grating) 314. By sliding the product into the cover, a dynamically varying band moiré image is formed. FIG. 32 illustrates a possible protection for pharmaceutical products such as medical drugs. The base layer 321 may cover the full surface of the possibly opaque support of the medical product. The revealing layer 322 may be embodied by a moveable stripe made of a sheet of plastic incorporating the revealing line grating. By pulling the revealing layer in and out or by moving it laterally, a dynamically moving band moiré image is formed. FIG. 33 illustrates schematically another possible embodiment of the present invention for the protection of products that are marketed in a package comprising a sliding transparent plastic front 331 and a rear board 332, which may be printed and carry a description of the product. Such packages are often used for selling video and audio cables, or any other products, that are kept within the hull (or recipient) 333 of plastic front 331. Often packages of this kind have a small hole 334 in the top of the rear board and a matching hole 335 in plastic front 331, in order to facilitate hanging the packages in the selling points. The rear board 332 may carry at least one base layer 336, and the plastic front may carry at least one revealing layer 337, so that when the package is closed, band moiré patterns are generated between at least one revealing layer and at least one base layer. Here, again, while the sliding plastic front 331 is slided along the rear board 332, a dynamically moving band moiré image is formed. FIG. 34 illustrates schematically yet another possible embodiment of the present invention for the protection of products that are packed in a box 340 with a rotating lid 341. The rotating lid 341 carries at least one base layer 342, and the box itself carries at least one revealing layer 343. When the box is closed, base layer 342 is located just behind revealing layer 343, so that band moiré patterns are generated. And when opening the box by rotating its lid 341, a dynamically moving band moiré image is formed. Depending on the base layer and revealing transformations, the generated band moiré image patterns may also move radially (as described in Example E). FIG. 35 illustrates schematically yet another possible embodiment of the present invention for the protection of products that are marketed in bottles (such as vine, whiskey, perfumes, etc.). For example, the product label 351 which is affixed to bottle 352 may carry base layer 353, while another label 354, which may be attached to the bottle by a decorative thread 355, carries the revealing layer 356. The authentication of the product can be done in by superposing and moving the revealing layer 356 of label 354 on top of the base layer 353 of label 351. This forms a dynamically moving band moiré image, for example with the name of the product evolving in shape and layout according to the relative superposition positions of the base and revealing layers. FIG. 36 illustrates a further embodiment of the present invention for the protection of watches 362. A base band grating layer may be created on the plastic armband 361 of a watch. The revealing line grating may be part of a second layer 360 able to move slightly along the armband. When the revealing line grating moves on top of the base band grating located on the armband, moire patterns may move in various directions and at different speeds. The moiré patterns may also move radially in and out when the revealing line grating moves on top of the base band grating located on the armband (see Example C). Computing System for the Synthesis of Base and/or Revealing Layers Thanks to the comprehensive band moiré image layout model, a large number of possible transformations as well as many different transformation and positioning constants can be used to automatically generate base band grating layers and revealing line grating layers yielding a large number of rectilinear or curvilinear static band moiré images or dynamic band moiré images exhibiting specific properties when moving one layer on top of the other. The large number of possible band moiré images which can be automatically generated provides the means to create individualized security documents and corresponding authentication means. Different classes or instances of documents may have individualized base layer layouts, individualized revealing layer layouts and either the same or different band moiré image layouts. A correspondence can be established between document content information and band moiré image synthesizing information, i.e. information about the respective layouts of base band grating, revealing line grating and band moiré image layers. For example, on a travel ticket, the information may comprise a ticket number, the name of the ticket holder, the travel date, and the departure and arrival locations. On a business contract, the information may incorporate the title of the document, the names of the contracting parties, the signature date, and reference numbers. On a diploma, the information may comprise the issuing institution, the name of the document holder and the document delivery date. On a bank check, the information may comprise the number printed on the check as well as the name of the person or the company which emits the check. On a banknote, the information may simply comprise the number printed on a banknote. One may easily create for a given document content information a corresponding band moiré image layout information, i.e. one transformation and one set of constants for the band moiré image layer layout and one transformation and one set of constants for the revealing line grating layer layout, said transformations and constants being selected from a large set of available transformations and transformation constants, for example stored within a transformation library. Individualized security documents comprising individualized base layers and corresponding revealing layers as authentication means may be created and distributed via a document security computing and delivery system (see FIG. 36, 370). The document security computing and delivery system operable for the synthesis and delivery of security documents and of authentication means comprises a server system 371 and client systems 372, 378. The server system comprises a base layer and revealing layer synthesizing module 375, a repository module 376 creating associations between document content information and corresponding band moiré image synthesizing information and an interface 377 for receiving requests for registering a security document, for generating a security document comprising a base layer, for generating a base layer to be printed on a security document or for creating a revealing layer laid out so as to reveal the band moiré image associated to a particular document or base layer. Client systems 372, 378 emit requests 373 to the server system and get the replies 374 delivered by the interface 377 of the server system. Within the server system, the repository module 376, i.e. the module creating associations between document content information and corresponding band moiré image synthesizing information is operable for computing from document information a key to access the corresponding document entry in the repository. The base band grating layer and revealing line grating layer synthesizing module 375 is operable, when given corresponding band moiré image synthesis information, for synthesizing the base band grating layer and the revealing line grating layer. Band moiré image synthesizing information comprises: a desired reference band moiré image in the original space, a band moiré orientation φ in the original space (as default value, e.g. 90°), a preferred revealing layer period Tr in the original space, a moiré displacement orientation β in the original space (orientation of replication vector t, i.e. β=a tan ty/tx) and the transformations g2(xt,yt) and m1(xt,yt), m2(xt,yt) mapping respectively the revealing layer and the band moiré image layer from the transformed space to the original space or as an alternative, the transformations g2(xt,yt) and h1(xt,yt),h(xt,yt) mapping respectively the revealing layer and the base band layer from the transformed space to the original space. The base band grating layer and revealing line grating layer synthesizing module is operable for synthesizing the base layer and the revealing layer from band moiré image synthesizing information either provided within the request from the client system or provided by the repository module. According to the band moiré image synthesizing information, the base band period replication vector t is computed and the base band layer is created in the original space. The module is also operable for computing from the transformation m1(xt,yt),m2(xt,yt) defining the band moiré image layout in the transformed space the corresponding transformation h1(xt,yt),h2(xt,yt) defining the base band layer layout in the transformed space. The server system's interface module 377 may receive from client systems (a) a request comprising document content information for creating a new document entry; (b) a request to register in a document entry band moiré image synthesis information delivered within the request message; (c) a request to generate band moiré image synthesis information associated to a given document and to register it into the corresponding document entry; (d) a request to issue a base layer for a given document; (c) a request to issue a revealing layer for a given document; Upon receiving a request 373, the server system's interface module interacts with the repository module in order to execute the corresponding request. In the cases of requests to issue a base or a revealing layer, the server system's interface module 377 transmits the request first to the repository module 376 which reads from the document entry the corresponding band moiré image synthesis information and forwards it to the base and revealing grating layer synthesizing module 375 for synthesizing the requested base or revealing layer. The interface module 377 delivers the requested base or revealing layer to the client system. The client system may print the corresponding layer or display it on a computer. Generally, for creating a new document, the interface module will deliver the printable base layer which comprises the base band grating. For authenticating a document, the interface module will deliver the revealing layer which comprises the line grating. As an alternative, the server system may further offer two (or more) levels of protection, one offered to the large public and one reserved to authorized personal, by providing for one document at least two different revealing layers, generating each one a different type of static or dynamic band moiré image. Thanks to the document security computing and delivery system, one may create sophisticated security document delivery services, for example the delivery of remotely printed (or issued) security documents, the delivery of remotely printed (or issued) authenticating devices (i.e. revealing layers), and the delivery of reference band moiré images, being possibly personalized according to information related to the security document to be issued or authenticated. Further Advantages of the Present Invention The advantages of the new authentication and anticounterfeiting methods disclosed in the present invention are numerous. 1. The comprehensive band moiré layout model disclosed in the present invention enables computing the exact layout of a band moiré image generated by the superposition of a base band grating and of a revealing line grating to which known geometric transformations are applied. The comprehensive band moiré layout model also allows specifying a given revealing line grating layout and computing a base band grating layout yielding, when superposed with the revealing line grating, a desired reference band moiré image layout. 2. An unlimited number of geometric transformations being available, a large number of base band grating and revealing line grating designs can be created according to different criteria. For example, the triplet formed by base band grating layout, revealing line grating layout and band moiré image layout may be different for each individual document, for each class of documents or for documents issued within different time intervals. The immense number of variations in base band grating layout, revealing line grating layout and band moiré image layout makes it very difficult for potential counterfeiters to forger documents whose layouts may vary according to information located within the document or according to time. 3. Since the same band moiré image may be generated when superposing different revealing layers on top of correspondingly computed base layers, base and revealing layers may be divided into several portions, each yielding the same band moiré image layout, but with different layouts of base and revealing layers. Since the shape of the masks determining the different portions within the base and revealing layers may be freely chosen, one may create revealing line and base band layers having a complex interlaced structure. Furthermore, the number of different portions may be freely chosen, thereby enabling the generation of very complex base layer and revealing layer layouts, which are extremely hard to forger. 4. Since the comprehensive band moiré layout model allows, for a given band moiré image layout, to freely chose the layout of the revealing line grating, one may optimize the layouts of the base and the revealing layers so as to reveal details which are only printable at the high resolution and with the possibly non-standard inks of the original printing device. Lower resolution devices or devices which do not print with the same inks as the original printing device will not be able to print these details and therefore no valid band moire image will be generated when superposing the revealing layer on top of a counterfeited base layer. 5. The band moiré layout model also allows predicting how moving the revealing layer on top of the base layer or vice-versa affects the resulting band moiré image. Depending on the respective layouts of a pair of base band grating and revealing line grating layers, the following situations may occur when moving the revealing layer on top of the base layer (or vice-versa): the revealing layer may move on top of the base layer without inducing new deformations of the revealed band moiré image; the revealing layer may move on top of the base layer only along one predetermined direction without deforming the revealed band moiré image; in all other directions, the revealed band moire image is subject to a deformation; when moving the revealing layer on top of the base layer, the revealed band moire image is subject to a periodic deformation; when moving the revealing layer on top of the base layer, the revealed band moire image is subject to a radial displacement and possibly a smooth deformation of its width to height ratio. any displacement of the revealing layer on top of the base layer induces a deformation of the revealed band moiré image. 6. The comprehensive band moiré layout model also allows to conceive base band grating and revealing line grating layouts, which generate, when moving the revealing layer on top of the base layer, a desired reference dynamic transformation of the resulting band moiré image. Example C shows that a rectilinear revealing layer superposed on top of a correspondingly computed base layer yields a circularly laid out band moiré image. When moving the rectilinear revealing layer on top of the base layer, the moiré image patterns move radially toward the exterior or the interior of the circular and moiré image layout and may possibly be subject to a smooth deformation of its width to height ratio. Example E shows another example, where rotating the revealing layer on top of the base layer, at the coordinate system origin, yields moiré image patterns which move toward the exterior or the interior of the circular and moiré image layout, depending on the rotation direction. 7. A curvilinear band moiré image having the same layout as a reference band moiré image can be generated by deducing according to the band moiré layout model the geometric transformations to be applied to the base layer and to the revealing layer. Since one of the two layer transformations can be freely chosen, the curvilinear base band layer may be conceived to incorporate orientations and frequencies, which have a high probability of generating undesired secondary moirés when scanned by a scanning device (color photocopier, desktop scanner). Such orientations are the horizontal, vertical and 45 degrees orientations, as well as the frequencies close to the frequencies of scanning devices (300 dpi, 600 dpi, 1200 dpi). 8. The base band layer generated according to the band moiré layout model may be populated with opaque color patterns printed side by side at a high registration accuracy, for example with the method described in U.S. patent application Ser. No. 09/477,544 (Ostromoukhov, Hersch). Since the band moiré patterns generated by the superposition of the base grating and of the revealing line grating are very sensitive to any microscopic variations of the pattern residing in the base bands of the base layer, any document protected according to the present invention is very difficult to counterfeit. The revealed band moiré patterns serve as a means to easily distinguish between a real document and a falsified one. 9. A further important advantage of the present invention is that it can be used for authenticating documents by having the base band or the revealing line layer placed on any kind of support, including paper, plastic materials, diffractive devices (holograms, kinegrams) etc., which may be opaque, semi-transparent or transparent. Furthermore, the present invented method can be incorporated into the background of security documents (for example by placing the base layer in the background and by allowing to write or print on top of it). Because it can be produced using standard original document printing processes, the present method offers high security without additional cost. 10. A further advantage relies on the fact that model-based synthesis of band moiré images enables generating a huge number of base layer variants, and revealing layer variants and band moiré image variants. Many different base layer and revealing layer layout pairs may be conceived so as to generated, upon superposition of base and revealing layer, the same band moiré image layout. A same band moiré image layout may however behave completely differently upon displacement of the revealing layer on top of the base layer. The band moiré image patterns may either remain as they are, undergo a smooth attractive transformation or be subject to a deformation which seems to destroy them, possibly in a periodic manner. Both the properties of static band moiré images (no revealing layer movement) or/and the properties of dynamic band moiré images may serve as authentication means. 11. A further advantage lies on the fact that both the base layer and the revealing layer can be automatically generated by a computer. A computer program generating automatically the base and revealing layers needs as input an original desired reference band moiré image, parameters of the base band grating and of the revealing line grating in the original space as well as geometric transformations and related constants enabling to create the base band grating layer and the revealing line grating layer in the transformed space. It is therefore possible to create a computer server operable for delivering both base layers and revealing layers. The computer server may be located within the computer of the authenticating personal or at a remote site. The delivery of the base and revealing layers may occur either locally, or remotely over computer networks. 12. Based on the computer server described in the section “Computing server for the synthesis of base and/or revealing layers” one may create sophisticated security document delivery services, for example the delivery of remotely printed (or issued) security documents and the delivery of remotely printed (or issued) authenticating devices, being possibly personalized according to information related to the security document to be issued or authentified. REFERENCES CITED U.S. Patent Documents U.S. Pat. No. 5,995,638 (Amidror, Hersch), 11/1999. Methods and apparatus for authentication of documents by using the intensity profile of moiré patterns, due assignee EPFL. U.S. Pat. No. 6,249,588 (Amidror, Hersch), 6/2001. Method and apparatus for authentication of documents by using the intensity profile of moiré patterns, due assignee EPFL. U.S. Pat. No. 5,018,767 (Wicker), May 28, 1991. Counterfeit protected document. U.S. Pat. No. 5,396,559 (McGrew), Mar. 7, 1995. Anticounterfeiting method and device utilizing holograms and pseudorandom dot patterns. U.S. Pat. No. 5,708,717 (Alasia), Jan. 13, 1998. Digital anti-counterfeiting software method and apparatus U.S. Pat. No. 5,999,280 (Huang), Dec. 7, 1999, Holographic anti-imitation method and device for preventing unauthorized reproduction, U.S. Pat. No. 5,694,229, (Drinkwater, B. W. Holmes), Dec. 2, 1997, Holographic Security Device U.S. Pat. No. 5,712,731 (Drinkwater et. al.), Jan. 27, 1998, Security device for security documents such as bank notes and credit cards. U.S. Pat. No. 5,032,003, (Antes), Jul. 16, 1991, Optically variable surface pattern. U.S. Pat. No. 4,984,824 (Antes and Saxer), Jan. 15, 1991, Document with an optical diffraction safety element. U.S. Pat. No. 4,761,253 (Antes), Aug. 2, 1988, Method and apparatus for producing a relief pattern with a microscopic structure, in particular having an optical diffraction effect U.S. Pat. No. 6,273,473, Self-verifying security documents (Taylor, Hardwick, Jackson, Zientek, Hibbert), Aug. 14, 2001, U.S. patent application Ser. No. 09/477,544 (Ostromoukhov, Hersch), Method and apparatus for generating digital halftone images by multi color dithering, filed 4th of Jan. 2000, due assignee EPFL. U.S. patent application Ser. No. 09/902,445, (Amidror and Hersch), 6/2001, Authentication of documents and valuable articles by using the moire intensity profile, filed 11th of Jun. 2001,due assignee EPFL. U.S. patent application Ser. No. 10/183,550, (Amidror), “Authentication with build-in encryption by using moiré intensity profiles between random layers, filed 28th of Jun. 2002, due assignee EPFL. U.S. patent application Ser. No. 10/270,546 filed 16th of Oct. 2002, “Authentication of documents and articles by moiré patterns”, inventors Hersch and Chosson, due assignee EPFL U.S. patent application Ser. No. 10/440,355, filed 19th of May 2003, Reproduction of security documents and color images with metallic inks, inventors Hersch, Emmel, Collaud, due assignee EPFL. Foreign Patent Documents United Kingdom Patent No. 1,138,011 (Canadian Bank Note Company), 12/1968. Improvements in printed matter for the purpose of rendering counterfeiting more difficult. OTHER PUBLICATIONS I. Amidror and R. D. Hersch, Fourier-based analysis and synthesis of moirés in the superposition of geometrically transformed periodic structures, Journal of the Optical Society of America A, Vol. 15, 1998; pp. 1100-1113. I. Amidror, The Theory of the Moiré Phenomenon, Kluwer Academic Publishers, 2000, Chapter 10, Moiré between repetitive non-periodic layer, 249-352. I. Amidror, R. D. Hersch, Quantitative analysis of multichromatic moiré effects in the superposition of coloured periodic layers, Journal of Modern Optics, Vol. 44, No. 5, 1997, 883-899 J. W. Harris and H Stocker, Handbook of Mathematics and Computational Science, Springer Verlag 1998, 319-329 W. Hospel, Application of laser technology to introduce security features on security documents in order to reduce counterfeiting, SPIE Vol. 3314, 1998, pp. 254-259. J. Huck, Mastering Moirés. Investigating Some of the Fascinating Properties of Interference Patterns, 2003, paper available by contacting the author, see http://pages.sbcglobal.net/joehuck/Pages/kit.html O. Mikami, New imaging functions of Moiré by fly's eye lenses, Japan Journal of Applied Physics, Vol. 14, No. 3, 1975; pp. 417-418. O. Mikami, New image-rotation using Moiré lenses, Japan Journal of Applied Physics, Vol. 14, No. 7, 1975; pp. 1065-1066. J. F. Moser, Document Protection by Optically Variable Graphics (Kinemagram), in Optical Document Security, Ed. R. L. Van Renesse, Artech House, London, 1998, pp. 247-266 K. Patorski, The moiré Fringe Technique, Elsevier 1993, pp. 14-21 G. Oster, M. Wasserman and C. Zwerling, Theoretical Interpretation of Moiré Patterns. Journal of the Optical Society of America, Vol. 54, No. 2, 1964, 169-175 V. Ostromoukhov and R. D. Hersch, Multi-color and artistic dithering, SIGGRAPH Annual Conference, 1999, pp. 425-432. B. Saleh, M. C. Teich, Fundamentals of Photonics, John Wiley, 1991, p. 116 D. Tollenaar, Moiré-Interferentieverschijnselen bij rasterdruk, Amsterdam Instituut voor Grafische Technick, 1945, English translation: Moiré in halftone printing interference phenomena, published in 1964, reprinted in Indebetouw G Czarnek R. (Eds.). 618-633, Selected Papers on Optical Moiré and Applications, SPIE Milestone Series, Vol. MS64, SPIE Press, 1992,
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates generally to the field of anti-counterfeiting and authentication methods and devices and, more particularly, to methods, security devices and apparatuses for authenticating documents and valuable products by band moiré patterns. Counterfeiting of documents such as banknotes is becoming now more than ever a serious problem, due to the availability of high-quality and low-priced color photocopiers and desk-top publishing systems. The same is also true for other valuable products such as CDs, DVDs, software packages, medical drugs, watches, etc., that are often marketed in easy to falsify packages. The present invention is concerned with providing a novel security element and authentication means offering enhanced security for devices needing to be protected against counterfeits, such as banknotes, checks, credit cards, identity cards, travel documents, valuable business documents, industrial packages or any other valuable products. The theory on which the present invention relies will be published at the beginning of August 2004, as a scientific contribution: “Band Moiré Images”, by R: D. Hersch and S. Chosson, SIGGRAPH'2004, ACM Computer Graphics Proceedings, Vol. 23, No. 3. Various sophisticated means have been introduced in the prior art for counterfeit prevention and for authentication of documents or valuable products. Some of these means are clearly visible to the naked eye and are intended for the general public, while other means are hidden and only detectable by the competent authorities, or by automatic devices. Some of the already used anti-counterfeit and authentication means include the use of special paper, special inks, watermarks, micro-letters, security threads, holograms, etc. Nevertheless, there is still an urgent need to introduce further security elements, which do not considerably increase the cost of the produced documents or goods. Moiré effects have already been used in prior art for the authentication of documents. For example, United Kingdom Pat. No. 1,138,011 (Canadian Bank Note Company) discloses a method which relates to printing on the original document special elements which, when counterfeited by means of halftone reproduction, show a moiré pattern of high contrast. Similar methods are also applied to the prevention of digital photocopying or digital scanning of documents (for example, U.S. Pat. No. 5,018,767, inventor Wicker). In all these cases, the presence of moiré patterns indicates that the document in question is counterfeit. Other prior art methods, on the contrary, take advantage of the intentional generation of a moiré pattern whose existence, and whose precise shape, are used as a means of authenticating the document. One known method in which a moiré effect is used to make visible a hidden pattern image encoded within a document (see background of U.S. Pat. No. 5,396,559 to McGrew, background of U.S. Pat. No. 5,901,484 to Seder, U.S. Pat. No. 5,708,717 to Alasia and U.S. Pat. No. 5,999,280 to Huang) is based on the physical presence of that image on the document as a latent image, using the technique known as “phase modulation”. In this technique, a line grating or a random screen of dots is printed on the document, but within the pre-defined borders of the latent image on the document the same line grating (or respectively, the same random dot-screen) is printed at a different phase, or possibly at a different orientation. For a layman, the latent image thus printed on the document is difficult to distinguish from its background; but when a revealing layer comprising an identical, but unmodulated, line grating or grating of lenticular lenses (respectively, random dot-screen) is superposed on the document, thereby generating a moiré effect, the latent image pre-designed on the document becomes clearly visible, since within its pre-defined borders the moiré effect appears in a different phase than in the background. Such a latent image may be recovered, since it is physically present on the document and only filled by lines at different phases or by a different texture. A second limitation of this technique resides in the fact that there is no enlargement effect: the pattern image revealed by the superposition of the base layer and of the revealing transparency has the same size as the latent pattern image. It should be stressed the disclosed band moire image synthesizing methods completely differ from the above mentioned technique of phase modulation since no latent image is present when generating a band moire image and since the band moiré image pattern shapes resulting from the superposition of a base band grating and a revealing line grating are a transformation of the original pattern shapes embedded within the base band grating. This transformation comprises always an enlargement, and possibly a rotation, a shearing, a mirroring, and/or a bending transformation. In addition, in the present invention, base band grating and revealing line grating layers can be created where translating respectively rotating the revealing layer on top of the base layer yields a displacement of the band moiré image patterns. Phase based modulation techniques allowing to hide latent images within a base layer are not capable of smoothly displacing and possibly transforming the revealed latent image when moving the revealing layer on top of the base layer. For example, they are unable to create a continuous displacement of the band moiré image patterns, such as for example the band moiré image patterns moving towards the center of a circular band moiré image layout. A further means of distinguishing phase modulation techniques from band moirés consists in verifying, once the revealing line grating is laid out on top of the base layer, if respectively a moiré pattern is produced by sampling only a single instance (i.e. one latent pattern image) or multiple instances of a base layer pattern (i.e. multiple base bands incorporating each one an instance of the base band pattern). U.S. Pat. No. 5,999,280, Holographic Anti-Imitation Method and Device for preventing unauthorized reproduction, inventor P. P. Huang, issued Dec. 7, 1999, discloses a holographic anti-imitation method and device where the superposition of a viewing device on top of a hidden pattern merged on a background pattern allows to visualize that hidden pattern. This disclosure relies on a technique similar to the phase modulation technique presented in the background section of U.S. Pat. No. 5,396,559 to McGrew, implemented on a holographic device. In contrast to U.S. Pat. No. 5,999,280, our invention relies on a completely different principle: several instances of the base band patterns are sampled and produce band moire image patterns which are enlarged and transformed instances of these base band patterns. Furthermore, our invention allows to generate dynamic band moire images, i.e. animations with dynamically behaving band moire image pattern shapes, which are impossible to achieve with patent U.S. Pat. No. 5,999,280. In U.S. Pat. No. 5,712,731 (Drinkwater et al.) a moiré based method is disclosed which relies on a periodic 2D array of microlenses. However, this last disclosure has the disadvantage of being limited only to the case where the superposed revealing structure is a microlens array and the periodic structure on the document is a constant 2D dot-screen with identical dot-shapes replicated horizontally and vertically. Thus, in contrast to the present invention, that invention excludes the use of gratings of lines as the revealing layer, both imaged on a transparent support (e.g. film) or as a grating of cylindric microlenses. Other moiré based methods disclosed by Amidror and Hersch in U.S. Pat. No. 6,249,588 and its continuation-in-part U.S. Pat. No. 5,995,638 rely on the superposition of arrays of screen dots which yields a moiré intensity profile indicating the authenticity of the document. These inventions are based on specially designed 2D periodic structures, such as dot-screens (including variable intensity dot-screens such as those used in real, gray level or color halftoned images), pinhole-screens, or microlens arrays, which generate in their superposition periodic moiré intensity profiles of chosen colors and shapes (typographic characters, digits, the country emblem, etc.) whose size, location and orientation gradually vary as the superposed layers are rotated or shifted on top of each other. In a third invention, U.S. patent application Ser. No. 09/902,445, Amidror and Hersch disclose new methods improving their previously disclosed methods mentioned above. These new improvements make use of the theory developed in the paper “Fourier-based analysis and synthesis of moirés in the superposition of geometrically transformed periodic structures” by I. Amidror and R. D. Hersch, Journal of the Optical Society of America A, Vol. 15, 1998, pp. 1100-1113 (hereinafter, “[Amidror98]”), and in the book “The Theory of the Moiré Phenomenon” by I. Amidror, Kluwer, 2000. According to this theory, said invention discloses how it is possible to synthesize aperiodic, geometrically transformed dot screens which in spite of being aperiodic in themselves, still generate, when they are superposed on top of one another, periodic moiré intensity profiles with undistorted elements, just like in the periodic cases disclosed by Hersch and Amidror in their previous U.S. Pat. No. 6,249,588 and its continuation-in-part U.S. Pat. No. 5,995,638. U.S. patent application Ser. No. 09/902,445 further disclosed how cases which do not yield periodic moirés can still be advantageously used for anticounterfeiting and authentication of documents and valuable products. In U.S. patent application Ser. No. 10/183,550 “Authentication with build-in encryption by using moiré intensity profiles between random layers”, inventor Amidror discloses how a moiré intensity profile is generated by the superposition of two specially designed random or pseudo-random dot screens. An advantage of that invention relies in its intrinsic encryption system offered by the random number generator used for synthesizing the specially designed random dot screens. However, the disclosures above made by inventors Hersch and Amidror (U.S. Pat. No. 6,249,588, U.S. Pat. No. 5,995,638. U.S. patent application Ser. No. 09/902,445) or Amidror (U.S. application Ser. No. 10/183,550) making use of the moiré intensity profile to authenticate documents have two limitations. The first limitation is due to the fact that the revealing layer is made of dot screens, i.e. of a set (2D array) of tiny dots laid out on a 2D surface. When dot screens are embodied by an opaque layer with tiny transparent dots or holes (e.g. a film with small transparent dots), only a limited amount of light is able to traverse the dot screen and the resulting moiré intensity profile is not easily visible. In these inventions, to make the moiré intensity profile clearly visible, one needs to work in transparent mode; both the revealing and the base layers need to be placed in front of a light source and the base layer should be preferably printed on a partly transparent support. In reflective mode, one needs to use a microlens array as master screen which, thanks to the light focussing capabilities of the lenses, make the moiré intensity profile clearly visible. The second limitation is due to the fact that the base layer is made of a two-dimensional array of similar dots (dot screen) where each dot has a very limited space within which only a few tiny shapes such as a few typographic characters or a single logo must be placed. This space is limited by the 2D frequency of the dot screen, i.e. by its two period vectors. The higher the 2D frequency, the less space there is for placing the tiny shapes which, when superposed with a 2D circular dot screen as revealing layer, produce as 2D moiré an enlargement of these tiny shapes. In U.S. patent application Ser. No. 10/270,546 (filed 16th of Oct. 2002, “Authentication of documents and articles by moiré patterns”, inventors Hersch and Chosson), a significant improvement was made by the discovery that a rectilinear base band grating incorporating original shapes superposed with a revealing straight line grating yields rectilinear moiré bands comprising moiré shapes which are a linear transformation of the original shapes incorporated within the base band grating. These moiré bands form a band moiré image. Since band moiré have a much better light efficiency than moiré intensity profiles relying on dots screens, band moiré images can be advantageously used in all case where the previous disclosures relying on 2D screens fail to show strong enough moiré patterns. In particular, the base band grating incorporating the original pattern shapes may be printed on a reflective support and the revealing line screen may simply be a film with thin transparent lines. Due to the high light efficiency of the revealing line screen, the band moiré patterns representing the transformed original band patterns are clearly revealed. A further advantage of band moiré images resides in the fact that it may comprise a large number of patterns, for example one or several words, one or several sophisticated logos, one or several symbols, and one or several signs. U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson), describes the layout of rectilinear band moiré images, when the layouts of base layer and the revealing layer are known. However it does not tell in which direction and at which speed the moiré shape moves when translating the rectilinear revealing layer on top of the rectilinear base layer. Furthermore, since it does not disclose a model for predicting the layout of the moiré image that can be produced when superposing a curvilinear base layer and a curvilinear revealing layer, band moirés image relying on curvilinear base or revealing layers need to be generated by a trial and error procedure. One tries first to generate examples of curvilinear line moirés produced by the superposition of line grating (according to the theory describing prior art line grating, see the article by I. Amidror and R. D. Hersch, Fourier-based analysis and synthesis of moirés in the superposition of geometrically transformed periodic structures, Journal of the Optical Society of America A, Vol. 15, 1998; pp. 1100-1113 or the book of I. Amidror, The Theory of the Moiré Phenomenon, Kluwer, 2000 , pages 249-352). Then, one replaces curvilinear lines of the line grating by bands, yielding a band grating. And finally, one verifies if the result is visually pleasing or not, and if not modifies the parameters of the base and revealing transformations and visualize again the results. When one of the layers layout is curvilinear, this trial and error method does not allow to compute a base band grating layer layout given a reference band moiré image layout and a revealing line grating layout. In addition, since the method relies on trial and error, it does not support the derivation of complicated geometric transformations, such as computing a base layer, which in superposition with a revealing layer forming a spiral shaped line grating yields a meaningful, visually pleasant band moiré image. The only reference band moiré image available with the trial and error method is the band moiré image produced by superposing the base and revealing layer derived thanks to the trial and error procedure. Furthermore, U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson) does neither give a precise technique for generating a reference rectilinear band moiré image layout with curvilinear base and revealing layer layouts nor does it give a means of generating a desired reference curvilinear band moiré image layout with a predetermined rectilinear or curvilinear revealing layer layout. U.S. patent application Ser. No. 10/270,546 teaches a method for creating variations of the appearing moiré patterns when moving the revealing layer on top of the base layer, however these variations rely only on modifications of the shapes embedded within the base band layer and do not rely, as in the present disclosure, on the geometric transformations of the base layer and/or the revealing layer. The present disclosure provides a band moiré image layout model allowing to compute not only the layout of a rectilinear band moiré image produced by superposing a rectilinear base band layer and a rectilinear revealing layer, but also in which direction and at which speed the rectilinear moiré shapes move when translating a the rectilinear revealing layer on top of the rectilinear base layer. For a curvilinear base layer and a curvilinear or rectilinear revealing layer, that model computes exactly the layout of the resulting rectilinear or curvilinear band moiré image obtained by superposing the base and revealing layers. Furthermore, one may specify a desired rectilinear or curvilinear band moiré image as well as one of the layers and the model is able to compute the layout of the other layer. Let us also note that the properties of the moiré produced by the superposition of two line gratings are well known (see for example K. Patorski, The moiré Fringe Technique, Elsevier 1993, pp. 14-16). Moiré fringes (moiré lines) produced by the superposition of two line gratings (i.e. set of lines) are exploited for example for the authentication of banknotes as disclosed in U.S. Pat. No. 6,273,473, Self-verifying security documents, inventors Taylor et al. Curved moiré fringes (moiré lines) produced by the superposition of curvilinear gratings are also known (see for example Oster G., Wasserman M., Zwerling C. Theoretical Interpretation of Moiré Patterns. Journal of the Optical Society of America, Vol. 54, No. 2, 1964, 169-175) and have been exploited for the protection of documents by a holographic security device (U.S. Pat. No. 5,694,229, issued Dec. 2, 1997, K. J. Drinkwater, B. W. Holmes). In U.S. patent application Ser. No. 10/270,546 as well as in the present invention, instead of using a line grating as base layer, we use as base layer a band grating incorporating in each band an image made of one-dimensionally compressed original patterns of varying shapes, sizes, intensities and possibly colors. Instead of obtaining simple moiré fringes (moiré lines) when superposing the base layer and the revealing line grating, we obtain a band moiré image which is an enlarged and transformed instance of the original band image. Joe Huck, a prepress professional, in his publication (2003) entitled “Mastering Moirés. Investigating Some of the Fascinating Properties of Interference Patterns, see also http://pages.sbcglobal.net/joehuck”, created band moiré images, both for artistic purposes and for creating designs incorporating moiré shapes floating within different perceived depth planes thanks to parallax effects. His publication only reports about vertically replicated horizontal base bands and a revealing layer made of horizontal lines, thereby generating moiré shapes moving only in the vertical direction. In contrast to the present invention, he neither provided a general-purpose framework for predicting the geometry of band moiré images as a function of base and revealing layer layouts, nor did he consider geometric transformations of base and revealing layers. In addition, he didn't consider applying band moiré images for document authentication.
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<SOH> SUMMARY <EOH>The present invention relates to the protection of devices which may be subject to counterfeiting attempts. Such devices comprise security documents such as banknotes, checks, trust papers, securities, identification cards, passports, travel documents, tickets, valuable business documents and valuable products such as optical disks, CDs, DVDs, software packages, medical products, watches. These devices need advanced authentication means in order to prevent counterfeiting attempts. The invention also relates to a document security computing and delivery system allowing to synthesize and deliver the security document as well as its corresponding authentication means. The present invention relies on a band moiré image layout model capable of predicting the band moiré image layer layout produced when superposing a base band grating layer of a given layout and a revealing line grating layer of a given layout. Both the base band grating layer and the revealing line grating layer may have a rectilinear or a curvilinear layout. The resulting band moiré image layout may also be rectilinear or curvilinear. Thanks to the band moiré image layout model, one can choose the layout of two layers selected from the set of base band grating layer, revealing line grating layer and band moiré image layer and obtain the layout of the third layer by computation, i.e. automatically. In contrast to the prior art invention described in U.S. patent application Ser. No. 10/270,546 (Hersch and Chosson), there is no need to proceed according to a manual trial and error procedure in order to create a revealing line grating layer layout and a base band grating layer layout which yield upon superposition a visually attractive easily perceivable band moiré image. In the present invention, one may simply define the band moiré image layout as well as the revealing line grating layout and compute the corresponding base band grating layout, which when superposed with the specified revealing line grating layout generates the specified band moiré image layout. The present disclosure also describes methods for computing the direction and speed at which rectilinear moiré shapes move when translating the corresponding rectilinear revealing line grating layer on top of the rectilinear base band grating layer. Furthermore, base band grating layer and revealing line grating layer layouts may be produced which yield, upon displacement of the revealing layer on top of the base layer (or vice-versa), a band moiré image whose patterns move along one direction or in the case of a concentric band moiré image, inwards or outwards in respect to the center of concentric moiré bands. In addition, it is possible to conceive a periodically varying revealing line grating layer which when translated on top of the base band grating layer, generates a band moiré image which is subject to a periodic deformation. Furthermore, thanks to the availability of a large number of geometric transformations and transformation variants (i.e. different values for the transformation constants), one may create classes of documents where each class of documents has its own individualized document protection. In addition, thanks to the band moire layout model, it is possible to synthesize one band moiré image partitioned into different portions synthesized each one according to a different pair of matching geometric transformations. This makes it practically impossible for potential counterfeiters to resynthesize a base layer without knowing in detail the relevant geometric transformations as well as the constants used to synthesize the authentic base layer. Thanks to the band moire image layout model, a computing system may automatically generate upon request an individualized protected security document by creating for a given document content information a corresponding band moiré image layout information. This computing system may then upon request synthesize and issue the security document with its embedded base band grating layer, the base band grating layer or the revealing line grating layer. To further enhance the security of documents, it is possible to synthesize a base band grating layer with non-overlapping shapes of different colors, for example created with non-standard inks, such as iridescent inks, inks visible under UV light or metallic inks, i.e. inks which are not available in standard color copiers or printers. The base band grating and revealing line grating layers may be printed on various supports, opaque or transparent materials. The revealing layer may be embodied by a line grating imaged on an transparent support or by other means such as cylindric microlenses. Such cylindric microlenses offer a high light efficiency and allow to reveal band moiré image patterns whose base band grating patterns are imaged at a high frequency on the base band layer. The base band grating layer may also be reproduced on an optically variable device and revealed either by a line grating imaged on a transparent support, by cylindric microlenses, or by a diffractive device such as Fresnel zone plates emulating cylindric microlenses. The fact that the generated band moiré patterns are very sensitive to any microscopic variations in the base and revealing layers makes any document protected according to the present invention extremely difficult to counterfeit, and serves as a means to distinguish between a real document and a falsified one. The present invention offers an additional protection by allowing to produce individual layouts either for individual or for classes of security documents. In addition, thanks to the band moiré image layout model, both the base band grating layer and the revealing line grating layer may be automatically generated. In the present disclosure different variants of the invention are described, some of which may be disclosed for the use of the general public (hereinafter: “overt” features), while other variants may be hidden (for example one of the set of base bands in a base layer combining multiple sets of base bands) and only detected by the competent authorities or by automatic devices (hereinafter: “covert” features).
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20040630
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20100706
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20060105
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83155.0
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G09B1918
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THOMAS, MIA M
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MODEL-BASED SYNTHESIS OF BAND MOIRE IMAGES FOR AUTHENTICATING SECURITY DOCUMENTS AND VALUABLE PRODUCTS
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UNDISCOUNTED
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ACCEPTED
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G09B
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10,879,254
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ACCEPTED
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Error Protection For Lookup Operations in Content-Addressable Memory Entries
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Error protection for lookup operations in a content-addressable memory (CAM) entries is disclosed. Values extended to include error protection or error protection fields are stored in CAM entries and a lookup operation is performed on a similarly extended lookup word to determine whether or not an entry is matched, that is, if all or all but some predetermined number of bits match one of the extended entries. For example, one implementation includes multiple CAM entries and logic configured to perform a lookup operation in parallel on each of the CAM entries based on a lookup word to determine whether or not a hit results, where the hit is determined if an entry matches the lookup word in all or all but k bit positions, where n and k are integers, n>k, and k>0.
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1. A method for identifying matching values in a content-addressable memory, the method comprising: determining a plurality of extended values based on a plurality of values, each of the plurality of extend values including a particular value of the plurality values and an error-correcting or error-detecting code generated based on the particular value, wherein each of the plurality of extend values are guaranteed to differ each other by at least n bits; programming a plurality of content-addressable memory entries with the plurality of extended values; and performing a lookup operation on said content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions; wherein n and k are integers, n>k, and k>0. 2. The method of claim 1, wherein k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. 3. The method of claim 1, comprising identifying a position of the entry in said content-addressable entries if the hit is determined for the entry. 4. The method of claim 1, wherein the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. 5. The method of claim 1, wherein said determining whether or not a hit results includes discriminating between a full and a partial hit, wherein the full hit corresponds to the entry matching the lookup word in all bit positions, and the partial hit corresponds to the entry matching the lookup word in all but k bit positions. 6. The method of claim 5, comprising in response to said determining the partial hit, performing a lookup operation in a second data structure to verify the hit result. 7. The method of claim 6, comprising in response to said determining the partial hit, updating the entry. 8. The method of claim 5, comprising in response to said determining the partial hit, updating the entry. 9. The method of claim 5, wherein k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. 10. A method for identifying matching values in a content-addressable memory, the method comprising: determining a plurality of extended values based on a plurality of values, each of the plurality of extend values including a particular value of the plurality values and an error-correcting or error-detecting code determined based on the particular value, wherein each of the plurality of extend values are guaranteed to differ each other by at least three bits; programming a plurality of content-addressable memory entries with the plurality of extended values; and performing a lookup operation on said content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but one bit position. 11. The method of claim 10, wherein said determining whether or not a hit results includes discriminating between a full and a partial hit, wherein the full hit corresponds to the entry matching the lookup word in all bit positions, and the partial hit corresponds to the entry matching the lookup word in all but one bit positions. 12. The method of claim 11, comprising in response to said determining the partial hit, performing a lookup operation in a second data structure to verify the hit result. 13. The method of claim 11, comprising in response to said determining the partial hit, updating the entry. 14. The method of claim 10, wherein the hit is also determined if the entry of said content-addressable memory entries matches the lookup word in all but two bit positions. 15. The method of claim 14, wherein said determining whether or not a hit results includes discriminating between a full and a partial hit, wherein the full hit corresponds to the entry matching the lookup word in all bit positions, and the partial hit corresponds to the entry matching the lookup word in all but two bit positions. 16. The method of claim 15, comprising in response to said determining the partial hit, performing a lookup operation in a second data structure to verify the hit result. 17. The method of claim 15, comprising in response to said determining the partial hit, updating the entry. 18. The method of claim 10, wherein the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. 19. An apparatus for identifying matching values in a content-addressable memory, the apparatus comprising: means for determining a plurality of extended values based on a plurality of values, each of the plurality of extend values including a particular value of the plurality values and an error-correcting or error-detecting code determined based on the particular value, wherein each of the plurality of extend values are guaranteed to differ each other by at least n bits; means for programming a plurality of content-addressable memory entries with the plurality of extended values; and means for performing a lookup operation on said content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions; wherein n and k are integers, n>k, and k>0. 20. The apparatus of claim 19, wherein k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. 21. The apparatus of claim 19, including means for generating the lookup word, the lookup word including an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. 22. The apparatus of claim 19, wherein said determining whether or not a hit results includes discriminating between a full and a partial hit, wherein the full hit corresponds to the entry matching the lookup word in all bit positions, and the partial hit corresponds to the entry matching the lookup word in all but k bit positions. 23. The apparatus of claim 22, comprising means for performing a lookup operation in a second data structure to verify the hit result in response to said determining the partial hit. 24. The apparatus of claim 22, comprising means for updating the entry in response to said determining the partial hit. 25. The apparatus of claim 22, wherein k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. 26. An apparatus comprising: a plurality of content-addressable memory entries; logic configured to perform a lookup operation on said content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions; wherein n and k are integers, n>k, and k>0. 27. The apparatus of claim 26, wherein said logic is configured to identify a position of the entry in said content-addressable entries if the hit is determined for the entry. 28. The apparatus of claim 26, wherein k=1. 29. The apparatus of claim 28, wherein n=3. 30. The apparatus of claim 26, wherein k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. 31. The apparatus of claim 26, wherein said determining whether or not a hit results includes discriminating between a full and a partial hit, wherein the full hit corresponds to the entry matching the lookup word in all bit positions, and the partial hit corresponds to the entry matching the lookup word in all but k bit positions. 32. The apparatus of claim 31, wherein k=1. 33. The apparatus of claim 32, wherein n=3. 34. The apparatus of claim 31, wherein k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number.
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TECHNICAL FIELD One embodiment of the invention relates to communications and computer systems, especially networked routers, packet switching systems, and other devices; and more particularly, one embodiment relates to error protection for lookup operations in a content-addressable memory entries; and more particularly, one embodiment stores values extended to include error-protection or error-protection fields and determines a match to a similarly extended lookup word if all or all but some predetermined number of bits match one of the extended entries. BACKGROUND The communications industry is rapidly changing to adjust to emerging technologies and ever increasing customer demand. This customer demand for new applications and increased performance of existing applications is driving communications network and system providers to employ networks and systems having greater speed and capacity (e.g., greater bandwidth). In trying to achieve these goals, a common approach taken by many communications providers is to use packet switching technology. Increasingly, public and private communications networks are being built and expanded using various packet technologies, such as Internet Protocol (IP). Note, nothing described or referenced in this document is admitted as prior art to this application unless explicitly so stated. A network device, such as a switch or router, typically receives, processes, and forwards or discards a packet based on one or more criteria, including the type of protocol used by the packet, addresses of the packet (e.g., source, destination, group), and type or quality of service requested. Additionally, one or more security operations are typically performed on each packet. But before these operations can be performed, a packet classification operation must typically be performed on the packet. Packet classification as required for, inter alia, access control lists (ACLs) and forwarding decisions, is a demanding part of switch and router design. The packet classification of a received packet is increasingly becoming more difficult due to ever increasing packet rates and number of packet classifications. For example, ACLs require matching packets on a subset of fields of the packet flow label, with the semantics of a sequential search through the ACL rules. IP forwarding requires a longest prefix match. Known approaches of packet classification include using custom application-specific integrated circuits (ASICs), custom circuitry, software or firmware controlled processors, and associative memories, including, but not limited to binary content-addressable memories (binary CAMs) and ternary content-addressable memories (ternary CAMs or TCAMs). Each entry of a binary CAM typically includes a value for matching against, while each TCAM entry typically includes a value and a mask. The associative memory compares a lookup word against all of the entries in parallel, and typically generates an indication of the highest priority entry that matches the lookup word. An entry matches the lookup word in a binary CAM if the lookup word and the entry value are identical, while an entry matches the lookup word in a TCAM if the lookup word and the entry value are identical in the bits that are not indicated by the mask as being irrelevant to the comparison operations. Associative memories are very useful in performing packet classification operations. As with most any system, errors can occur. For example, array parity errors can occur in certain content-addressable memories as a result of failure-in-time errors which are typical of semiconductor devices. When a packet classification lookup operation is performed on an associative memory with corrupted entries, a bit error in an entry can result in a false hit, or a false miss. A false hit occurs when the corrupted value of an entry matches the lookup value when it otherwise would not match that entry (and thus another entry or no entry should have been match). A false miss occurs when an entry should have been matched except for the corruption in the entry. This could result in no entry being matched or another lower-priority entry being match. When these lookup operations are used for packet classification, an incorrect match or miss presents a problem especially when identifying a route or performing a security classification. Error-correcting and error-detecting codes are well-known. For example, ANDREW S. TANENBAUM, COMPUTER NETWORKS, Prentice-Hall, 1981, pp. 125-132, discusses error-correcting and error-detecting codes, and is hereby incorporated by reference. Assume a codeword contains n bits of which m are data bits and r are error-correcting or error-detecting bits (e.g., redundant or check bits), with n=m+r. There are many well-known ways to generate the error-detecting and error-correcting bits. Given two codewords, it is possible to determine how many bits differ (e.g., by exclusively-OR'ing or one bit summing the corresponding bits of the two codewords and summing these results). The number of bit positions in which two codewords or a set of codewords differ is called the Hamming distance. A Hamming distance of d, means that it will require d single-bit errors to convert one codeword to another codeword. To detect j errors, a Hamming distance of j+1 is required because with such a code, there is no way that j single-bit errors can change a valid codeword into another valid codeword. Similarly, to correct j errors, a distance 2j+1 code because that way the legal codewords are so far apart that even with j changes, the original codeword is still closer than any other codeword, so it can be uniquely determined. A prior approach protects the associative memory entries with error detection or correction values when the associative memory is not being used to perform a lookup operation. For example, using a background operation, the associative memory entries are periodically checked and corrected for errors (e.g., read from their location and if an error, the correct value is written back). Another prior approach is to periodically over write each associative memory entry with the correct value. These and other prior approaches do not immediately detect the error, nor detect the error when a lookup operation is performed on the corrupted entry. Thus, there can be significant periods (e.g., several seconds to minutes which can be a very long time in the context of a packet switch) before such corrupted entry is corrected. Some random access memory (RAM) add error-correcting or error-detecting codes to each memory cell. As part of a read operation of a memory location, the data portion and the error-correcting or error-detecting code is read, which is then used to detect a possible error and/or correct a discovered error in the data portion. This is especially convenient to do as only one set of error-detecting/error correcting circuitry is required (i.e., to operate on the data read from the specified memory location). However, this approach is impractical for an associative memory, as each associative memory entry would need this complete circuitry, and the result of the error-corrected operation for each memory location would need to be compared to the lookup word for every lookup operation. Desired is a mechanism to reduce or eliminate the possible false hits or misses due to corrupted associative memory entries. SUMMARY Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for providing error protection for lookup operations in a content-addressable memory (CAM) entries. One embodiment stores values extended to include error-protection or error-protection fields and determines a match to a similarly extended lookup word if all or all but some predetermined number of bits match one of the extended entries. One embodiment for identifying matching values in a content-addressable memory determines a set of extended values based on an original set of values, with each of the extend values including its original value and an error-correcting or error-detecting code generated based on the original value, such that each of the extend values are guaranteed to differ each other by at least n bits. Content-addressable memory entries are programmed with the extended values. Lookup operations are then performed on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, with a hit being determined if an entry matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment includes multiple content-addressable memory entries, and logic configured to perform lookup operations simultaneously and in parallel on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment identifies a position of the matching entry. In one embodiment, the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. One embodiment identifies whether a determined hit is a full hit (all bits matched) or a partial hit (all but k bits matched). In one embodiment, k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. In one embodiment, in response to determining that there was a partial hit, a lookup operation is performed in a second data structure to verify the hit result. In one embodiment, in response to determining that there was a partial hit, the partially matching entry is updated to remove the any bit errors in the entry. One embodiment for identifying matching values in a content-addressable memory determines a set of extended values based on an original set of values, with each of the extend values including its original value and an error-correcting or error-detecting code generated based on the original value, such that each of the extend values are guaranteed to differ each other by at least three bits. Content-addressable memory entries are programmed with the extended values. Lookup operations are then performed on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, with a hit being determined if an entry matches the lookup word in all or all but one bit positions. One embodiment also determines a hit if an entry matches the lookup word in all but two bit positions. One embodiment identifies a position of a matching entry. In one embodiment, the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. One embodiment identifies whether a determined hit is a full hit or a partial hit. In one embodiment, in response to determining that there was a partial hit, a lookup operation is performed in a second data structure to verify the hit result. In one embodiment, in response to determining that there was a partial hit, the partially matching entry is updated to remove the any bit errors in the entry. BRIEF DESCRIPTION OF THE DRAWINGS The appended claims set forth the features of the invention with particularity. The invention, together with its advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which: FIG. 1A is a block diagram illustrating the generating of extend values/CAM entries including its original value and an error-correcting or error-detecting code generated based on the original value performed in one embodiment; FIG. 1B is a flow diagram illustrating a process used in one embodiment for generating of extend values/CAM entries including its original value and an error-correcting or error-detecting code generated based on the original value performed in one embodiment; FIG. 1C is a block diagram illustrating exemplary programmed CAM entries in one or more content addressable memories; FIG. 2A is a block diagram illustrating the generating of an extend lookup word including its original lookup value and an error-correcting or error-detecting code generated based on the original lookup value performed in one embodiment; FIG. 2B is a flow diagram illustrating a process used in one embodiment for generating of an extend lookup word including its original lookup value and an error-correcting or error-detecting code generated based on the original lookup value performed in one embodiment; FIG. 3A is a flow diagram illustrating a process used in one embodiment for performing a lookup operation on a set of extended CAM entries based on a lookup word; FIG. 3B is a flow diagram illustrating a process used in one embodiment for performing a lookup operation on a set of extended CAM entries based on a lookup word; FIG. 4A is a block diagram illustrating an embodiment that generates extended CAM entries and programs a CAM with extended entry matching logic and performs lookup operations thereon using generated extended lookup values; FIG. 4B is a block illustrating a system or component used in one embodiment that generates extended CAM entries and programs a CAM with extended entry matching logic and performs lookup operations thereon using generated extended lookup values; FIG. 5 is a block diagram illustrating one embodiment of a CAM with extended entry matching logic; FIG. 6A is a block diagram illustrating circuitry used in one embodiment of a CAM with extended entry matching logic for use in identifying whether or not three bits of an extended lookup word match all or all but one bit of a three-bit extended CAM entry; FIG. 6B is a block diagram illustrating circuitry used in one embodiment of a CAM with extended entry matching logic for use in identifying whether or not nine bits of an extended lookup word match all or all but one bit of a nine-bit extended CAM entry; and FIG. 6C is a block diagram illustrating circuitry used in one embodiment of a CAM with extended entry matching logic for use in identifying whether or not twenty-seven bits of an extended lookup word match all or all but one bit of a twenty-seven-bit extended CAM entry. DETAILED DESCRIPTION Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for providing error protection for lookup operations in a content-addressable memory entries. One embodiment stores values extended to include error-protection or error-protection fields and determines a match to a similarly extended lookup word if all or all but some predetermined number of bits match one of the extended entries. Embodiments described herein include various elements and limitations, with no one element or limitation contemplated as being a critical element or limitation. Each of the claims individually recites an aspect of the invention in its entirety. Moreover, some embodiments described may include, but are not limited to, inter alia, systems, networks, integrated circuit chips, embedded processors, ASICs, methods, and computer-readable media containing instructions. One or multiple systems, devices, components, etc. may comprise one or more embodiments, which may include some elements or limitations of a claim being performed by the same or different systems, devices, components, etc. The embodiments described hereinafter embody various aspects and configurations within the scope and spirit of the invention, with the figures illustrating exemplary and non-limiting configurations. Note, computer-readable media and means for performing methods and processing block operations are disclosed and are in keeping with the extensible scope and spirit of the invention. As used herein, the term “packet” refers to packets of all types or any other units of information or data, including, but not limited to, fixed length cells and variable length packets, each of which may or may not be divisible into smaller packets or cells. The term “packet” as used herein also refers to both the packet itself or a packet indication, such as, but not limited to all or part of a packet or packet header, a data structure value, pointer or index, or any other part or direct or indirect identification of a packet or information associated therewith. For example, often times a router operates on one or more fields of a packet, especially the header, so the body of the packet is often stored in a separate memory while the packet header is manipulated, and based on the results of the processing of the packet (i.e., the packet header in this example), the entire packet is forwarded or dropped, etc. Additionally, these packets may contain one or more types of information, including, but not limited to, voice, data, video, and audio information. The term “item” is used generically herein to refer to a packet or any other unit or piece of information or data, a device, component, element, or any other entity. The phrases “processing a packet” and “packet processing” typically refer to performing some steps or actions based on the packet contents (e.g., packet header or other fields), and such steps or action may or may not include modifying, storing, dropping, and/or forwarding the packet and/or associated data. The term “system” is used generically herein to describe any number of components, elements, sub-systems, devices, packet switch elements, packet switches, routers, networks, computer and/or communication devices or mechanisms, or combinations of components thereof. The term “computer” is used generically herein to describe any number of computers, including, but not limited to personal computers, embedded processing elements and systems, control logic, ASICs, chips, workstations, mainframes, etc. The term “processing element” is used generically herein to describe any type of processing mechanism or device, such as a processor, ASIC, field programmable gate array, computer, etc. The term “device” is used generically herein to describe any type of mechanism, including a computer or system or component thereof. The terms “task” and “process” are used generically herein to describe any type of running program, including, but not limited to a computer process, task, thread, executing application, operating system, user process, device driver, native code, machine or other language, etc., and can be interactive and/or non-interactive, executing locally and/or remotely, executing in foreground and/or background, executing in the user and/or operating system address spaces, a routine of a library and/or standalone application, and is not limited to any particular memory partitioning technique. The steps, connections, and processing of signals and information illustrated in the figures, including, but not limited to any block and flow diagrams and message sequence charts, may typically be performed in the same or in a different serial or parallel ordering and/or by different components and/or processes, threads, etc., and/or over different connections and be combined with other functions in other embodiments, unless this disables the embodiment or a sequence is explicitly or implicitly required (e.g., for a sequence of read the value, process the value—the value must be obtained prior to processing it, although some of the associated processing may be performed prior to, concurrently with, and/or after the read operation). Furthermore, the term “identify” is used generically to describe any manner or mechanism for directly or indirectly ascertaining something, which may include, but is not limited to receiving, retrieving from memory, determining, defining, calculating, generating, etc. Moreover, the terms “network” and “communications mechanism” are used generically herein to describe one or more networks, communications media or communications systems, including, but not limited to the Internet, private or public telephone, cellular, wireless, satellite, cable, local area, metropolitan area and/or wide area networks, a cable, electrical connection, bus, etc., and internal communications mechanisms such as message passing, interprocess communications, shared memory, etc. The term “message” is used generically herein to describe a piece of information which may or may not be, but is typically communicated via one or more communication mechanisms of any type. The term “storage mechanism” includes any type of memory, storage device or other mechanism for maintaining instructions or data in any format. “Computer-readable medium” is an extensible term including any memory, storage device, storage mechanism, and other storage and signaling mechanisms including interfaces and devices such as network interface cards and buffers therein, as well as any communications devices and signals received and transmitted, and other current and evolving technologies that a computerized system can interpret, receive, and/or transmit. The term “memory” includes any random access memory (RAM), read only memory (ROM), flash memory, integrated circuits, and/or other memory components or elements. The term “storage device” includes any solid state storage media, disk drives, diskettes, networked services, tape drives, and other storage devices. Memories and storage devices may store computer-executable instructions to be executed by a processing element and/or control logic, and data which is manipulated by a processing element and/or control logic. The term “data structure” is an extensible term referring to any data element, variable, data structure, database, and/or one or more organizational schemes that can be applied to data to facilitate interpreting the data or performing operations on it, such as, but not limited to memory locations or devices, sets, queues, trees, heaps, lists, linked lists, arrays, tables, pointers, etc. A data structure is typically maintained in a storage mechanism. The terms “pointer” and “link” are used generically herein to identify some mechanism for referencing or identifying another element, component, or other entity, and these may include, but are not limited to a reference to a memory or other storage mechanism or location therein, an index in a data structure, a value, etc. The term “one embodiment” is used herein to reference a particular embodiment, wherein each reference to “one embodiment” may refer to a different embodiment, and the use of the term repeatedly herein in describing associated features, elements and/or limitations does not establish a cumulative set of associated features, elements and/or limitations that each and every embodiment must include, although an embodiment typically may include all these features, elements and/or limitations. In addition, the phrase “means for xxx” typically includes computer-readable medium containing computer-executable instructions for performing xxx. In addition, the terms “first,” “second,” etc. are typically used herein to denote different units (e.g., a first element, a second element). The use of these terms herein does not necessarily connote an ordering such as one unit or event occurring or coming before another, but rather provides a mechanism to distinguish between particular units. Additionally, the use of a singular tense of a noun is non-limiting, with its use typically including one or more of the particular thing rather than just one (e.g., the use of the word “memory” typically refers to one or more memories without having to specify “memory or memories,” or “one or more memories” or “at least one memory”, etc.). Moreover, the phrases “based on x” and “in response to x” are used to indicate a minimum set of items x from which something is derived or caused, wherein “x” is extensible and does not necessarily describe a complete list of items on which the operation is performed, etc. Additionally, the phrase “coupled to” is used to indicate some level of direct or indirect connection between two elements or devices, with the coupling device or devices modifying or not modifying the coupled signal or communicated information. The term “subset” is used to indicate a group of all or less than all of the elements of a set. The term “subtree” is used to indicate all or less than all of a tree. Moreover, the term “or” is used herein to identify a selection of one or more, including all, of the conjunctive items. Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for providing error protection for lookup operations in a content-addressable memory (CAM) entries. One embodiment stores values extended to include error-protection or error-protection fields and determines a match to a similarly extended lookup word if all or all but some predetermined number of bits match one of the extended entries. One embodiment for identifying matching values in a content-addressable memory determines a set of extended values based on an original set of values, with each of the extend values including its original value and an error-correcting or error-detecting code generated based on the original value, such that each of the extend values are guaranteed to differ each other by at least n bits. Content-addressable memory entries are programmed with the extended values. Lookup operations are then performed on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, with a hit being determined if an entry matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment includes multiple content-addressable memory entries, and logic configured to perform lookup operations simultaneously and in parallel on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment identifies a position of the matching entry. In one embodiment, the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. One embodiment identifies whether a determined hit is a full hit (all bits matched) or a partial hit (all but k bits matched). In one embodiment, k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. In one embodiment, in response to determining that there was a partial hit, a lookup operation is performed in a second data structure to verify the hit result. In one embodiment, in response to determining that there was a partial hit, the partially matching entry is updated to remove the any bit errors in the entry. One embodiment for identifying matching values in a content-addressable memory determines a set of extended values based on an original set of values, with each of the extend values including its original value and an error-correcting or error-detecting code generated based on the original value, such that each of the extend values are guaranteed to differ each other by at least three bits. Content-addressable memory entries are programmed with the extended values. Lookup operations are then performed on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, with a hit being determined if an entry matches the lookup word in all or all but one bit positions. One embodiment also determines a hit if an entry matches the lookup word in all but two bit positions. One embodiment identifies a position of a matching entry. In one embodiment, the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. One embodiment identifies whether a determined hit is a full hit or a partial hit. FIG. 1A is a block diagram illustrating the generating of extend values/CAM entries including its original value and an error-correcting or error-detecting code generated based on the original value performed in one embodiment. An original value 100 (e.g., one normally stored in a CAM entry) is identified. An extended value/CAM entry 110 is generated to include original value 110 (e.g., in original value field 111) and the error code portion 112 generated by error-correcting or error-detecting code generator 105 (stored in error code field 112). Note, the format of extended value/CAM entry 110 is extensible and can an vary among embodiments. For example, fields 111 and 112 might be in a different order and/or bits from each of the fields 111 and 112 interleaved. Also, there are many well-known error-correcting and/or error-detecting code generation mechanisms, and thus these will not be discussed in detail. Embodiments are extensible and are not limited to any particular known or to be developed error-correcting or error-detecting code generation algorithm or mechanism. Rather, embodiments leverage these various techniques to match the needs of the operating environment and application. For example, if bit error rates are low, then an error-correcting and/or error-detecting code generation mechanism with a small Hamming distance will typically be sufficient. In environments with a higher bit error rate, an error-correcting and/or error-detecting code generation mechanism with a larger Hamming distance will typically be used. Also, one embodiment updates or refreshes CAM entries periodically, so the selection of the error-correcting and/or error-detecting code generation mechanism will typically take into consideration the bit error generation rate and this refresh rate. Also, this Hamming distance determines a maximum number of differences in bits that will be interpreted as a match. For example, with a Hamming distance of three, one embodiment identifies an entry as matching if there are zero or one bit differences between the entry and the lookup word. Typically, if all entries are guaranteed to be different by n bits, whether due to adding error code portions to original values or simply the original values themselves (e.g., without being supplemented with error code portions), then up to k bit differences can be determined to be considered as a match, where n and k are integers, n>k, and k>0. Note, the difference between n and k might vary among embodiments, and can range from one to n−1. Typically, embodiments use a value of k less than n/2, so that a single partially matching entry will be identified. If a value of k greater than or equal to n/2 is used and the entries actually vary in distance by n bits, then there could be a corrupted entry that matches in all but k bits and there could also be a corrupted entry that matches by n-k bits (which would be closer to the original lookup word). One embodiment uses a value for k much smaller than n/2, such as k=1 or k=2, to limit the number of corrupted bits which will result is a hit (e.g., a partial hit). One embodiment also determines whether or not there was a suspected hit (e.g., not all bits matched and more than k bits differing, but less than n/2 bits differing), so that this entry can be corrected by software or by some other mechanism if needed (e.g., the entry is corrupted). Note, when integer division is used, the value of k less than n/2 (non-integer division) is equivalent to k being less than or equal to the result of the integer division of (n/2) when n is an odd number and k being less than the result of the integer division of (n/2) when n is an even number. One embodiment, in response to identifying a matching corrupted entry within the range employed by the embodiment, performs another lookup operation in a second data structure, either based on the lookup word or on the matching entry or its identified position in the CAM entries, to verify that the corrupted entry corresponds to an entry that matches the lookup word and/or to acquire the correct value of the entry so that it can update the entry with the correct value to remove the bit errors. FIG. 1B is a flow diagram illustrating a process used in one embodiment for generating of extend values/CAM entries including its original value and an error-correcting or error-detecting code generated based on the original value performed in one embodiment. Processing begins with process block 140, and proceeds to process block 142. While there are more values to extend, then the next original value is identified in process block 144; an error-correction or error-detection code is generated based on the original value in process block 146; the original value and the error code are combined in some manner to create the extended value in process block 148; and the extended value is programmed into a CAM entry (e.g., an extended CAM entry) in process block 150. Note, one embodiment performs blocks 144-148 for all original values, and then subsequently programs the CAM entries in succession or in some other manner. For example, FIG. 1C illustrates these extended values 181-189 programmed in CAM entries 180. When all extended values have been generated and extended entries programmed, then processing is complete as indicated by process block 152. FIG. 2A is a block diagram illustrating the generating of an extend lookup word including its original lookup value and an error-correcting or error-detecting code generated based on the original lookup value performed in one embodiment. An original lookup value 200 (e.g., one normally used as for a lookup operation in a CAM) is identified. An extended lookup word 210 is generated to include original lookup value 200 (e.g., in original lookup value field 211) and the error code portion 212 generated by error-correcting or error-detecting code generator 205 (stored in error code field 212). Note, the format of extended lookup word 210 is extensible and can an vary among embodiments. For example, fields 211 and 212 might be in a different order and/or bits from each of the fields 211 and 212 interleaved. FIG. 2B is a flow diagram illustrating a process used in one embodiment for generating of an extend lookup word including its original lookup value and an error-correcting or error-detecting code generated based on the original lookup value performed in one embodiment. Processing begins with process block 240, and proceeds to process block 242, wherein an original lookup value is identified. In process block 244, an error-correction or error-detection code is generated based on the original lookup value. In process block 246, the original lookup value and the error code are combined in some manner to create the extended lookup value (i.e., in a manner consistent with the creation of the extended CAM entries). In process block 248, the a lookup operation is performed on the extended CAM entries based on the extended lookup value to indicate whether or not a hit results, typically along with an identification of the matching extended CAM entry. One embodiment also indicates whether or not the hit was a complete hit (e.g., all bits matched) or a partial hit (e.g., less than all bits matched but within the predetermined number of bits required to be considered a partial hit). One embodiment also indicates whether or not there was a suspected hit (e.g., not all bits matched and more than k bits differing, but less than n/2 bits differing). In one embodiment, in response to a partial or suspected hit, the corresponding CAM entry is updated to correct any bit errors. In one embodiment, in response to a partial or suspected hit, a lookup operation is performed on a second data structure, (e.g., the one used in generating the CAM entries or a different one), to confirm whether or not whether an entry was actually matched. In one embodiment, in response to a partial or suspected hit, the entry is updated to remove any bit errors. Processing is complete as indicated by process block 249. FIG. 3A is a flow diagram illustrating a process used in one embodiment for performing a lookup operation on a set of extended CAM entries based on a lookup word. Processing begins with process block 300, and proceeds to process block 302, wherein a lookup value is identified. In process block 304, a lookup operation is performed on the CAM entries based on the lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment discriminates between whether a determined hit is a full hit (all bits matched) or a partial hit (all but k bits matched). As determined in process block 306, if a hit result was determined, then in process block 310, one or more hit indications are generated to identify the hit. One embodiment signals whether the hit was a full hit or a partial hit. Otherwise, in process block 308, a miss indication is generated. Processing is complete as indicated by process block 312. FIG. 3B is a flow diagram illustrating a process used in one embodiment for performing a lookup operation on a set of extended CAM entries based on a lookup word. Processing begins with process block 340, and proceeds to process block 342, wherein a lookup value is identified. In process block 344, a lookup operation is performed on the CAM entries based on the lookup word to determine whether or not a full or partial hit results, wherein a full hit is determined if an entry of said content-addressable memory entries matches the lookup word in all bit positions and a partial hit results if an entry matches the lookup word in all but k bit positions, wherein n and k are integers, n>k, and k>0. As determined in process block 346, if a miss result (e.g., not a full or partial hit) was determined, then in process block 348, one or more miss indications are generated to identify the miss. As determined in process block 350, if a full hit result was determined, then in process block 352, one or more hit or full hit indications are generated to identify the hit, typically including indicating the position of the matching entry. Otherwise, in process block 354, a lookup operation is performed on a second data structure to verify that the identified partially matching entry actually matches the lookup value. For example, a second data structure might include an array in memory of entries corresponding to the non-corrupted entries stored in the CAM. Using the identified position of the partially matching entry, the correct entry value can be retrieved from the second data structure. As determined in process block 356, if the uncorrupted value of the entry does not match the lookup word, then in process block 358, one or more miss indications are generated to identify the miss. Otherwise, in process block 360, one or more hit or partial hit indications are generated to identify the hit, typically including indicating the position of the matching entry. In one embodiment, the matching CAM entry is also updated to remove the bit errors (e.g., by overwriting the corrupted CAM entry with the correct entry value). Processing is complete as indicated by process block 362. Note, as one skilled in the art would readily understand, there are many different possible ways of signaling between a hit or not a hit (i.e., a miss) and among a partial hit, full hit or no hit (i.e., miss), such as, but not limited to using a signal line or signaling bit for each possible result or encoding the information on possibly fewer signal lines. For example, one embodiment uses a single line or bit to identify whether there was a hit or no hit. One embodiment uses an additional line to identify if there was a hit, whether the hit was a full or partial hit. One embodiment encodes these signals on one or more lines or in on or more bits. For example: 00=no hit, 01=partial hit, 10=full hit (and an indication of either hit can be generated using an OR operation on these encoded signals or values). FIG. 4A illustrates a system 400 using error protected CAM entries. that generates extended CAM entries and programs a CAM with extended entry matching logic and performs lookup operations thereon using generated extended lookup values. System 400 may be, for example, part of a router, communications, computer or any other system or component. In one embodiment, control logic 410 generates extended entries, programs, updates, generates extended lookup values and performs lookup operations on associative memory or memories 412 by providing updates and extended lookup words 411. In one embodiment, control logic 410 includes custom circuitry, such as, but not limited to discrete circuitry, ASICs, memory devices, processors, etc. Control logic 410 also typically stores indications of desired actions to be taken via updates 414 in adjunct memory or memories 415. In one embodiment, control logic 410 includes a memory for storing a second data structure of the original, uncorrupted CAM entries for use in verifying a partial match and/or for updated corrupted CAM entries. A hit result 413 (e.g., whether or not there was a hit, and possibly whether the hit was a full or partial hit) is typically provided to control logic 410 and to adjunct memory or memories 415, which produces result 416. In one embodiment, a single chip or ASIC contains system 400. In one embodiment, a single chip or ASIC contains system 400 except for packet processor 405. In one embodiment, less than all or even no two components of system 400 reside on the same chip or ASIC. In one embodiment, packets 401 are received by packet processor 405. In addition to other operations (e.g., packet routing, security, etc.), packet processor 405 typically generates lookup value 403 (either an original or extended lookup value) which is provided to control logic 410, which generates the extended lookup value 411 if required, and initiates one or more CAM lookup operations on content-addressable memory or memories 412. A result 407 (e.g., a packet classification identification or action) is typically returned to packet processor 405, and in response, one or more of the received packets are manipulated and forwarded as indicated by packets 409. FIG. 4B is a block illustrating a system or component used in one embodiment for generating and/or programming an associative memory with extended entries and/or performing lookup operations thereon using generated extended lookup values. System 420 may be part of a router, communications, computer or any other system or component. In one embodiment, system 420 performs one or more processes corresponding to one of the diagrams illustrated herein or otherwise described herein. In one embodiment, system 420 includes a processing element 421, memory 422, storage devices 423, one or more content-addressable memories with extended entry matching logic 424, and an interface 425 for connecting to other devices, which are coupled via one or more communications mechanisms 429 (shown as a bus for illustrative purposes). Various embodiments of system 420 may include more or less elements. The operation of system 420 is typically controlled by processing element 421 using memory 422 and storage devices 423 to perform one or more tasks or processes, such as programming and performing extended lookup operations using content-addressable memory or memories 424. Memory 422 is one type of computer readable media, and typically comprises random access memory (RAM), read only memory (ROM), flash memory, integrated circuits, and/or other memory components. Memory 422 typically stores computer executable instructions to be executed by processing element 421 and/or data which is manipulated by processing element 421 for implementing functionality in accordance with one embodiment of the invention. Storage devices 423 are another type of computer readable media, and typically comprise solid state storage media, disk drives, diskettes, networked services, tape drives, and other storage devices. Storage devices 423 typically store computer executable instructions to be executed by processing element 421 and/or data which is manipulated by processing element 421 for implementing functionality in accordance with one embodiment of the invention. In one embodiment, processing element 421 provides control and data information (e.g., lookup words, modification data, profile IDs, etc.) to content-addressable memory or memories 424, which perform lookup operations to generate lookup results and possibly error indications, which are received and used by processing element 421 and/or communicated to other devices via interface 425. FIG. 5 illustrates a CAM 500, which includes extended entry matching logic to determine whether or not a hit results (e.g., a full or a partial hit). Note, as used in this document, the term “extended” refers to those values etc. actually extended to include an error-correcting or error-detecting value to guarantee an appropriate Hamming distance, as well as those values natively having an appropriate distance without having to add any additional field or value. Typically, information is not guaranteed to provide such distance, so for ease of reader understanding, this term is typically used. As shown, CAM 500 includes extended CAM cells 510 and 520 which store the values to be matched (511 and 522) against lookup word 520 by comparison logic (512 and 522) to generate indications of whether or not a hit (i.e. a full or partial hit) results for each extended CAM cell (510 and 520). If a hit is identified by a high value, then OR gate 540 can be used to identify based on results 515 and 525 whether a hit resulted (high) or no hit resulted (low—i.e., a miss) 541. Encoder 550 (possibly a priority encoder) is used to identify (551) the position of the matching (i.e., full or partial hit) entry (e.g., which CAM cell 510, 520 matched). Note, one embodiment extends the notification of whether or not a hit results by signaling an indication of whether or not it was a full or a partial hit. Comparison logic 512, 522 may vary among embodiments. For example, in one embodiment, comparison logic 512, 522 includes a processing element. In one embodiment, comparison logic 512, 522 includes discrete logic. In one embodiment, comparison logic 512, 522 includes logic to exclusively-OR or one-bit sum each of the corresponding bits of the lookup word 530 and corresponding stored value (511, 521) in the CAM cell (510, 520), with these results each summed to identify the number of different bit positions between the lookup word 530 and corresponding stored value (511, 521). One or more comparison operations can be performed to identify a hit (i.e., the sum is less than or equal to k) or individually a full hit (i.e., the sum is zero) and a partial hit (i.e., the sum is greater than zero and is less than or equal to k). One embodiment, determines and provides external indications of whether a determined hit was a full hit or a partial hit. FIGS. 6A-C illustrate a modular way to identify whether or not there is a full or partial match, with k being equal to one. In other words, whether or not there is a full match (no bits differ) or a partial match (one bit position differs between a lookup word and the entire CAM entry). FIG. 6A illustrates building blocks and a configuration for use with three bit lookup words and CAM entries. FIG. 6B uses these building blocks and illustrates a configuration for use with nine bit lookup words and CAM entries. FIG. 6C uses some of these building blocks and illustrates a configuration for use with nine bit lookup words and CAM entries. FIG. 6A illustrates circuitry used in a CAM with extended entry matching logic for use in identifying whether or not three bits of an extended lookup word match all or all but one bit of a three-bit extended CAM entry. Three bit input stage 600 includes the 3-bit value 601 of the stored entry and receives the 3-bit value 602 of the lookup word, and provides signals 603-605 whether the corresponding bits match. Three bit compare (TBC) circuitry 610 then uses OR and AND gates as shown to generate a MISS signal 611 (i.e., high if two or more bits differ, else low—i.e., low if a full or partial hit) and a HIT_L signal 612 (i.e., low if all bits match, else high). Output stage 620 generates a full hit signal 622 (i.e., high if a full hit, else low) and a partial hit signal 621 (i.e., high if a partial hit, else low). Thus, in order to identify whether there was a hit (i.e., either a full or partial hit), either the inverted value of MISS (HIT_L) signal 611 or the output of an OR gate OR'ing signals 621 and 622 can be used. FIG. 6B illustrates circuitry 650 used in a CAM with extended entry matching logic for use in identifying whether or not nine bits of an extended lookup word match all or all but one bit of a three-bit extended CAM entry. Three three-bit input stages 600 (FIG. 6A), four three bit compares (TBCs) 610 (FIG. 6A), and one output stage 620 (FIG. 6A) are used and interconnected as shown. FIG. 6C illustrates circuitry 670 used in a CAM with extended entry matching logic for use in identifying whether or not twenty-seven bits of an extended lookup word match all or all but one bit of a three-bit extended CAM entry. Nine three-bit input stages 600 (FIG. 6A), thirteen three bit compares (TBCs) 610 (FIG. 6A), and one output stage 620 (FIG. 6A) are used and interconnected as shown. In view of the many possible embodiments to which the principles of our invention may be applied, it will be appreciated that the embodiments and aspects thereof described herein with respect to the drawings/figures are only illustrative and should not be taken as limiting the scope of the invention. For example and as would be apparent to one skilled in the art, many of the process block operations can be re-ordered to be performed before, after, or substantially concurrent with other operations. Also, many different forms of data structures could be used in various embodiments. The invention as described herein contemplates all such embodiments as may come within the scope of the following claims and equivalents thereof.
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<SOH> BACKGROUND <EOH>The communications industry is rapidly changing to adjust to emerging technologies and ever increasing customer demand. This customer demand for new applications and increased performance of existing applications is driving communications network and system providers to employ networks and systems having greater speed and capacity (e.g., greater bandwidth). In trying to achieve these goals, a common approach taken by many communications providers is to use packet switching technology. Increasingly, public and private communications networks are being built and expanded using various packet technologies, such as Internet Protocol (IP). Note, nothing described or referenced in this document is admitted as prior art to this application unless explicitly so stated. A network device, such as a switch or router, typically receives, processes, and forwards or discards a packet based on one or more criteria, including the type of protocol used by the packet, addresses of the packet (e.g., source, destination, group), and type or quality of service requested. Additionally, one or more security operations are typically performed on each packet. But before these operations can be performed, a packet classification operation must typically be performed on the packet. Packet classification as required for, inter alia, access control lists (ACLs) and forwarding decisions, is a demanding part of switch and router design. The packet classification of a received packet is increasingly becoming more difficult due to ever increasing packet rates and number of packet classifications. For example, ACLs require matching packets on a subset of fields of the packet flow label, with the semantics of a sequential search through the ACL rules. IP forwarding requires a longest prefix match. Known approaches of packet classification include using custom application-specific integrated circuits (ASICs), custom circuitry, software or firmware controlled processors, and associative memories, including, but not limited to binary content-addressable memories (binary CAMs) and ternary content-addressable memories (ternary CAMs or TCAMs). Each entry of a binary CAM typically includes a value for matching against, while each TCAM entry typically includes a value and a mask. The associative memory compares a lookup word against all of the entries in parallel, and typically generates an indication of the highest priority entry that matches the lookup word. An entry matches the lookup word in a binary CAM if the lookup word and the entry value are identical, while an entry matches the lookup word in a TCAM if the lookup word and the entry value are identical in the bits that are not indicated by the mask as being irrelevant to the comparison operations. Associative memories are very useful in performing packet classification operations. As with most any system, errors can occur. For example, array parity errors can occur in certain content-addressable memories as a result of failure-in-time errors which are typical of semiconductor devices. When a packet classification lookup operation is performed on an associative memory with corrupted entries, a bit error in an entry can result in a false hit, or a false miss. A false hit occurs when the corrupted value of an entry matches the lookup value when it otherwise would not match that entry (and thus another entry or no entry should have been match). A false miss occurs when an entry should have been matched except for the corruption in the entry. This could result in no entry being matched or another lower-priority entry being match. When these lookup operations are used for packet classification, an incorrect match or miss presents a problem especially when identifying a route or performing a security classification. Error-correcting and error-detecting codes are well-known. For example, ANDREW S. TANENBAUM, C OMPUTER N ETWORKS , Prentice-Hall, 1981, pp. 125-132, discusses error-correcting and error-detecting codes, and is hereby incorporated by reference. Assume a codeword contains n bits of which m are data bits and r are error-correcting or error-detecting bits (e.g., redundant or check bits), with n=m+r. There are many well-known ways to generate the error-detecting and error-correcting bits. Given two codewords, it is possible to determine how many bits differ (e.g., by exclusively-OR'ing or one bit summing the corresponding bits of the two codewords and summing these results). The number of bit positions in which two codewords or a set of codewords differ is called the Hamming distance. A Hamming distance of d, means that it will require d single-bit errors to convert one codeword to another codeword. To detect j errors, a Hamming distance of j+1 is required because with such a code, there is no way that j single-bit errors can change a valid codeword into another valid codeword. Similarly, to correct j errors, a distance 2j+1 code because that way the legal codewords are so far apart that even with j changes, the original codeword is still closer than any other codeword, so it can be uniquely determined. A prior approach protects the associative memory entries with error detection or correction values when the associative memory is not being used to perform a lookup operation. For example, using a background operation, the associative memory entries are periodically checked and corrected for errors (e.g., read from their location and if an error, the correct value is written back). Another prior approach is to periodically over write each associative memory entry with the correct value. These and other prior approaches do not immediately detect the error, nor detect the error when a lookup operation is performed on the corrupted entry. Thus, there can be significant periods (e.g., several seconds to minutes which can be a very long time in the context of a packet switch) before such corrupted entry is corrected. Some random access memory (RAM) add error-correcting or error-detecting codes to each memory cell. As part of a read operation of a memory location, the data portion and the error-correcting or error-detecting code is read, which is then used to detect a possible error and/or correct a discovered error in the data portion. This is especially convenient to do as only one set of error-detecting/error correcting circuitry is required (i.e., to operate on the data read from the specified memory location). However, this approach is impractical for an associative memory, as each associative memory entry would need this complete circuitry, and the result of the error-corrected operation for each memory location would need to be compared to the lookup word for every lookup operation. Desired is a mechanism to reduce or eliminate the possible false hits or misses due to corrupted associative memory entries.
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<SOH> SUMMARY <EOH>Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for providing error protection for lookup operations in a content-addressable memory (CAM) entries. One embodiment stores values extended to include error-protection or error-protection fields and determines a match to a similarly extended lookup word if all or all but some predetermined number of bits match one of the extended entries. One embodiment for identifying matching values in a content-addressable memory determines a set of extended values based on an original set of values, with each of the extend values including its original value and an error-correcting or error-detecting code generated based on the original value, such that each of the extend values are guaranteed to differ each other by at least n bits. Content-addressable memory entries are programmed with the extended values. Lookup operations are then performed on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, with a hit being determined if an entry matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment includes multiple content-addressable memory entries, and logic configured to perform lookup operations simultaneously and in parallel on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, wherein the hit is determined if an entry of said content-addressable memory entries matches the lookup word in all or all but k bit positions, wherein n and k are integers, n>k, and k>0. One embodiment identifies a position of the matching entry. In one embodiment, the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. One embodiment identifies whether a determined hit is a full hit (all bits matched) or a partial hit (all but k bits matched). In one embodiment, k is less than or equal to the result of the integer division of (n/2) when n is an odd number and k is less than the result of the integer division of (n/2) when n is an even number. In one embodiment, in response to determining that there was a partial hit, a lookup operation is performed in a second data structure to verify the hit result. In one embodiment, in response to determining that there was a partial hit, the partially matching entry is updated to remove the any bit errors in the entry. One embodiment for identifying matching values in a content-addressable memory determines a set of extended values based on an original set of values, with each of the extend values including its original value and an error-correcting or error-detecting code generated based on the original value, such that each of the extend values are guaranteed to differ each other by at least three bits. Content-addressable memory entries are programmed with the extended values. Lookup operations are then performed on the content-addressable memory entries based on a lookup word to determine whether or not a hit results, with a hit being determined if an entry matches the lookup word in all or all but one bit positions. One embodiment also determines a hit if an entry matches the lookup word in all but two bit positions. One embodiment identifies a position of a matching entry. In one embodiment, the lookup word includes an original lookup value and a lookup word error-correcting or error-detecting code generated based on the original lookup value. One embodiment identifies whether a determined hit is a full hit or a partial hit. In one embodiment, in response to determining that there was a partial hit, a lookup operation is performed in a second data structure to verify the hit result. In one embodiment, in response to determining that there was a partial hit, the partially matching entry is updated to remove the any bit errors in the entry.
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20040629
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20071030
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20051229
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93715.0
| 0
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ELMORE, STEPHEN C
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ERROR PROTECTION FOR LOOKUP OPERATIONS IN CONTENT-ADDRESSABLE MEMORY ENTRIES
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,879,286
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ACCEPTED
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Standoff for use with uncoiled bare wire and insulated runs of an open coil electric resistance heater, method of use, and an open coil resistance heater using the standoff
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An open coil resistance heater uses one or more standoffs to engage and support the generally straight or uncoiled run of bare or insulated wire that is part of the resistance wire of the heater. The standoff has slots, which are sized to engage the bare or insulated wires for support purposes, and is removably mountable to the heater frame for supporting the run of uncoiled wire.
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1. In an open coil electric resistance heater having at least one resistance wire element for heating, a coiled portion of the resistance wire element being supported by a plurality of insulators, with the plurality of insulators being supported by a frame, the at least one resistance wire element including at least one run of uncoiled wire run, the improvement comprising at least one standoff made of electrically insulating material, the at least one standoff further comprising a standoff body including means for mounting the body to the frame, the standoff body having at least one slot sized to engage and support a portion of the at least one run of uncoiled wire. 2. The heater of claim 1, wherein the coiled portion of the resistance wire element terminates in at least one run of uncoiled wire lead for connection to a source of power, the uncoiled wire lead being supported by the at least one slot. 3. The heater of claim 2, wherein the coiled portion of the resistance wire element terminates in a pair of runs of uncoiled wire leads, the standoff body having a pair of slots for supporting each of the runs of the uncoiled wire leads. 4. The heater of claim 2, wherein the heater is a two-stage heater having a pair of electric resistance elements for heating, the at least one standoff supporting a portion of at least one of the runs of uncoiled wire lead for one of the electric resistance elements. 5. The heater of claim 4, wherein the standoff body has a pair of slots for supporting each of the runs of the uncoiled wire leads of the one electric resistance element. 6. The heater of claim 2, further comprising a pair of standoffs mounted to the frame for supporting respective portions of the at least one run of uncoiled wire lead. 7. The heater of claim 6, wherein the heater has a pair of runs of uncoiled wire leads, with each standoff body having a pair of slots for supporting each of the runs of the uncoiled wire leads. 8. The heater of claim 2, wherein the at least one run of uncoiled wire lead includes one or more portions surrounded by an insulator, the slot of the standoff being sized for supporting either bare uncoiled wire lead adjacent to the insulator or a portion of the insulator. 9. The heater of claim 3, wherein each run of uncoiled wire lead includes a portion surrounded by an insulator, each slot of the standoff being sized to supporting either bare uncoiled wire lead adjacent to the insulator or a portion of the insulator. 10. The heater of claim 1, wherein the means for mounting further comprises a pair of opposing slots in the standoff body, and a cutout in the frame, each slot engaging a respective portion of the frame adjacent the cutout for mounting, a portion of the frame including a tab adjacent to one of the respective portions of the frame, bending of the tab retaining the standoff in the cutout. 11. The heater of claim 10, further comprising a pair of standoffs, and first and second cutouts in the frame for respective mounting of each standoff. 12. The heater of claim 10, wherein the cutout is sized to allow for rotation of the standoff and for mounting of the standoff to the frame. 13. The heater of claim 11, wherein the first cutout is sized to allow for rotation of the standoff, for mounting to the frame and for a crossover wire of the resistance wire element, and the second cutout is sized to allow for rotation of the standoff and for mounting to the frame. 14. In an open coil two stage electric resistance heater having a pair of resistance wire elements for heating, a coiled portion of each resistance wire element being supported by a plurality of insulators, with the plurality of insulators being supported by a frame, each resistance wire element terminating in a pair of uncoiled and partially insulated wire leads for connection to a source of power via a terminal mounted to the heater, the improvement comprising at least one standoff, the at least one standoff made of electrically insulating material and further comprising a standoff body including means for mounting the body to the frame, the standoff body having opposing slots, each opposing slot sized to engage and support a bare wire portion of one of the pair of runs of uncoiled wire lead of one of the resistance wire elements. 15. The heater of claim 14, further comprising a pair of standoffs for supporting the pair of runs of uncoiled wire lead. 16. An uncoiled electric resistance wire standoff comprising a standoff body made of an electrically insulating material, the standoff body further comprising means for mounting the body to a heater frame, the standoff body having at least one slot sized to engage and support a portion of an uncoiled wire of an open coil electric resistance heater. 17. The standoff of claim 16, wherein the standoff body has two slots, each sized to engage one of a pair of uncoiled wires of an open coil electric resistance heater. 18. The standoff of claim 16, wherein mounting means further comprises a pair of opposing slots in the standoff body, the slots sized to engage portions of a metal frame of the open coil electric resistance heater. 19. The standoff of claim 16, wherein the standoff body has at least one L-shaped arm extending from a side face of the standoff body, a portion of the L-shaped arm and the side face forming the slot. 20. The standoff of claim 19, wherein the standoff body has a pair of opposing L-shaped arms to engage a pair of runs of uncoiled wire. 21. The standoff of claim 16, wherein the at least one slot is sized to engage an insulated resistance wire. 22. The standoff of claim 17, wherein the means for mounting further comprises a pair of opposing slots in a body portion of the standoff, each slot sized to engage a portion of a heater frame for mounting purposes. 23. The standoff of claim 20, wherein the means for mounting further comprises a pair of opposing slots in a body portion of the standoff, each slot sized to engage a portion of a heater frame for mounting purposes. 24. In a method of heating using an open coil electric resistance heater, wherein the heater has at least one resistance wire element for heating, a coiled portion of the resistance wire element being supported by a plurality of insulators, with the plurality of insulators being supported by a frame, the at least one resistance wire element including at least one run of uncoiled wire portion, the at least one resistance wire element being energized to generate heat, the improvement comprising supporting the at least one uncoiled wire portion using at least one standoff made of an electrically insulating material that is mounted to the frame and positioned between the uncoiled portion and the frame. 25. The method of claim 24, wherein the uncoiled wire portion extends from a terminal end of the coiled portion of the resistance wire element to a terminal block, the standoff being positioned between the terminal end and the terminal block for supporting the uncoiled wire portion. 26. The method of claim 25, wherein the heating is either radiant or convection heating.
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FIELD OF THE INVENTION The present invention is directed to a standoff for use in an open coil electric resistance heater, and in particular to a standoff that engages uncoiled portions of the electrical resistance wire of the heater to minimize shorting or grounding conditions. BACKGROUND ART The use of a single resistance wire formed into a helical coil for use in electric resistance heating either for heating moving air, for radiant heating or for convection heating is well known in the prior art. In one type of heater, the resistance coils are energized to heat air passing over the coils, the heated air then being directed in a particular manner for heating purposes. One application using such a heater is an electric clothes dryer. Examples of open coil heaters are found in U.S. Pat. Nos. 5,329,098, 5,895,597, and 5,925,273, all owned by Tutco, Inc. of Cookeville, Tenn. Each of these patents is incorporated by reference in its entirety herein. One type of an open coil electric resistance heater is a two stage heater described in U.S. Pat. No. 5,925,273. A side view of this type of heater is shown in FIG. 1 and designated by the reference numeral 10. The heater 10 has two heater elements 10a and 10b, optimally for use in a clothes dryer. The elements 10a and 10b are supplied with electricity via terminals 12 extending from the terminal block 28. The heater elements 10a, 10b are supported by a metal plate 14, which in turn supports a plurality of support insulators 16, which are well known in the art. The support insulators 16 support and isolate coiled portions of the elements, 10a and 10b, during operation of the heater. The heater 10 includes opposing sidewalls (one shown as 6 in FIG. 1), wherein projections in the plate 14 extend through slots 20 in the sidewall 6 to allow the sidewalls to support the plate. Each of the electric heater elements, 10a and 10b, is arranged in series of electrically continuous coils which are mounted on the plate 14 in a spaced-apart substantially parallel arrangement. Each heater assembly 10a and 10b is arranged substantially equally and oppositely on both sides of the plate. Crossover portions 22a and 22b of each heater element 10a and 10b are provided wherein each crossover links one coil of each of the elements mounted on one side of the plate 14 with another coil of the same element found on the other side of the plate. The plate 14 has several cutout portions (not shown) to provide adequate clearance for the crossover portions, 22a and 22b, and the anticipated drooping or sagging movement of such portions. Electricity is supplied to the heater assembly through the terminal block 28. The heater elements, 10a and 10b, are arranged so that the terminal connector portions or wire leads 32 and 34 which extend from an end 38 of each of the mounted coil sections to the terminal block are as short as possible. This aids in eliminating or reducing the need for supporting the connector portions. For the longer runs, the wire leads, 32 and 34, are partially enclosed with an insulating member 36. The insulating member 36 may be formed from any type of insulating material suitable for this purpose, e.g., a ceramic type. The insulating member is generally tubular in shape and rigid. One of the most significant aspects of the open coil heater design is that of routing the uncoiled connector portions extending from the ends of heater coils (resistance wire leads) so they are protected from contact with either adjacent live heater wire sections or from contact with bare metal, either of which creates a potential failure. The resistance wire leads for connecting to the termination point(s) for ultimate connection to a source of electrical power must therefore be routed and protected from dead metal and from electrically live parts of a different polarity than the resistance wire leads. When physical separation cannot be achieved using design techniques available to the technology, the prior art, as noted above, has used insulating tubes made of appropriate materials for the application, e.g., ceramic tubes are used for routing and isolating the resistance wires lead, see items 36 in FIG. 1. However, the mere use of ceramic tubes alone to protect the resistance wire leads does not always solve all of the problems in these types of heaters. The manufacturing of open coil heaters that use insulating tubes to protect a length of bare resistance wire lead section often requires more than one tube section for each wire lead. That is, to span longer sections it is necessary to use multiple tube pieces. At the point where two tubes meet there is, of course, a narrow opening and when electrical spacing requirements per safety standards are considered, the opening can be or is significant. The same condition may exist at the free end of a ceramic tube, i.e. where there is no adjacent tube. Even under the best of conditions there are over-the-surface and through-the-air distance conditions occurring where an electric potential exists. This electrical potential could result in either a ground out or an electrical short should movement occur, both of which are dangerous conditions to be avoided. There are practical reasons why multiple tubes may be required to span one section of bare resistance wire. The first is that longer sections of insulating tubes are more expensive to manufacture than shorter sections, so that using a number of shorter sections may be more economical. Another reason that longer tubes are shunned is that shipping and handling relatively long tubes during heater assembly result in damage or breakage. Further it is often more economical to have available multiple short pieces that are of a lower cost per unit length in order to accommodate various length requirements than to have exact lengths made for every requirement. A given length requirement can be fulfilled by using two or more short pieces of insulating tubes to span the longer required distance. Even when a single insulating tube is of sufficient length to span the distance from the end of the heating coil to the termination point, there may be lack of clearance at a tube end between the wire exiting the tube and adjacent dead metal. A further problem results should a tube break and the result is another potential electrical short or ground out condition being created. It is also impractical to use an insulating tube with a wall thickness great enough to overcome the dangerous electrical conditions noted above. Thick walled tubes are costly to produce and handle during the manufacture of open coil heaters. In the art of open coil heaters, separate tabs, clips, straps or stand-offs made of metal have been used to position and permanently restrain the insulating tubes containing resistance wires as described above. However, this method of restraint often creates mechanical stress resulting in tube breakage. Though a break in the tube in itself doesn't mean the wires will move from their intended routing, a possible electrical short or a ground condition may result as an effect of the wire contacting the above described metal restraining means. In light of the shortcomings in protecting the bare wire leads or the problems when using ceramic leads of open coil electric resistance heaters, a need has developed for improved ways to minimize the possibility of shorting or grounding conditions. The present invention responds to this need by providing a standoff for use with the resistance wire leads or other uncoiled runs to minimize these grounding/shorting conditions. SUMMARY OF THE INVENTION It is a first object of the invention to provide an improved open coil resistance heater. It is another object of the invention to provide an open coil resistance heater that uses one or more standoffs that support uncoiled wire runs, particularly wire leads of the heater. Yet another object of the invention is a standoff for use with an open coil heater or other type of heater whereby the standoff can engage wire runs, particularly wire leads, of the heater to protect them from shorting/grounding in the run. One further object of the invention is an improvement in methods of providing heat using electric resistance heaters, wherein the heater includes one or more standoffs for the heater's uncoiled wire, particularly wire leads, to minimize shorting or grounding conditions. Other objects and advantages will become apparent as a description of the invention proceeds. In satisfaction of the foregoing objects and advantages of the invention, the invention is an improvement in heaters employing open coil electric resistance elements. More particularly, the invention involves heaters that contain one or more runs of uncoiled or generally straight wire runs. A given run may extend between two coiled portions of the heater element. Alternatively, the run may extend between the coiled portion of the heating element and a terminal block or the like that is adapted for connection to a source of power, this run forming a wire lead to assist connecting the resistance wire to a supply of power. The coiled portion of the resistance wire element is supported by a plurality of insulators, with the plurality of insulators being supported by a frame. The invention is the use of one or more standoffs that are made of electrically insulating material. Each standoff further comprises a standoff body including means for mounting the body to the frame. Each standoff body has at least one slot sized to engage and support a portion of the run of uncoiled wire, either in a bare state or in an insulated state. If the heater employs a pair of runs that require support, the standoff body can be configured to have a pair of slots to accommodate the pair of wire runs. The slots can be sized to support either bare wire or insulated wire. The standoff is especially adapted for two stage heaters, wherein the heating element most remote from the terminal block has long runs of wire that can use one or more standoffs for support. In one embodiment, the standoff can be used with insulated wire leads wherein the insulation is positioned adjacent the standoff such that the standoff is supporting a bare wire run and offering an insulating effect on the bare wire run as well. The means for mounting the standoff can involve any number of mounting configurations from fasteners, to specially configured slots in the heater frame, to adhesives or combinations thereof. In one mode, the mounting means comprises a pair of opposing slots in the standoff body, and a cutout in the frame. Each slot engages a respective portion of the frame adjacent the cutout for mounting, a portion of the frame including a tab adjacent to one of the respective portions of the frame. To secure the standoff, the tab can be bent to retain the standoff in the cutout. Depending on the length of the uncoiled wire run, more than one cutout and standoff can be utilized for wire run support. The cutout can be shaped to allow for rotation of the standoff for mounting purposes, and/or sized to allow for both standoff rotation and crossover wire passage to link coils on opposite sides of the frame. The invention also entails an improvement in a method of heating using an open coil electric resistance heater, wherein the heater has at least one resistance wire element for heating, a coiled portion of the resistance wire element being supported by a plurality of insulators, with the plurality of insulators being supported by a frame, the wire element including one or more uncoiled wire runs that require support. The run or runs can be the uncoiled bare or insulated wire leads beginning at coiled portions of the wire element and terminating in a pair of uncoiled bare wire leads for connection to a source of power via a terminal mounted to the heater. As noted above, the uncoiled runs, bare or insulated can also extend between two coiled portions of the resistance wire element. As part of this method, at least one resistance wire element is energized to generate heat, either via radiation or convection. The improvement in the method comprises supporting the bare or insulated wire runs using at least one standoff made of the electrically insulating material that is mounted to the frame and positioned so as to support one or more uncoiled wire runs. BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the drawings of the invention wherein: FIG. 1 is a side view of a prior art open coil electric resistance heater; FIG. 2 is a perspective view of the standoff of FIG. 2; FIG. 3 is a perspective view of a portion of an open coil electric resistance heater using a standoff for wire lead support; FIG. 4 is a plan view of a portion of a frame configured for standoff mounting; FIG. 5 is an enlarged view of a portion of the frame of FIG. 4 showing greater detail; FIG. 6 is an alternative embodiment of the standoff of FIG. 2; and FIG. 7 is a schematic of yet another embodiment wherein the standoff supports an uncoiled portion of resistance wire. DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention offers advantages in the field of open coil resistance heaters in that the problems in grounding or shorting as a result of wire leads or other uncoiled wire runs coming into contact with dead metal or the like are significantly reduced. This improvement is achieved by using a standoff to support the uncoiled wire runs that extend between the coiled resistance wires and terminals for later connection to a power source. One embodiment of the standoff aspect of the invention is illustrated in FIG. 2, and is designated by the reference numeral 40. The standoff 40 includes a generally rectangular standoff body 41 having a pair of L-shaped arms 43, each extending from one side of the body 41. Each free end 45 (the longer leg of the L-shaped arm) of the arms 41 coupled with a portion of the side face 47 of the body 41 forms a slot 49. The length of the slot is determined by the thickness of the body 41. The width of the slot is determined by the length of the shorter leg 51 of the L-shaped arm 43. The depth of the slot 49 is controlled by the length of the longer leg 45 of the L-shaped arm 43. In the embodiment depicted in FIG. 2, each slot 49 is sized to engage bare resistance wire. However, the slot 49 could be made bigger to engage an insulated resistance wire, such as one that is surrounded by a ceramic tube as shown in FIG. 1. This could be accomplished by making the shorter leg portion 51 longer, thus increasing the distance between the side face 47 and free end leg 45. Referring to FIG. 3, a perspective view of a portion of a two stage heater is shown, wherein a coiled portion 55 from one stage and a second coiled portion 56 from another stage are shown schematically. The standoff 40 is shown supporting a bare wire lead 53 that extends from the coiled portion 55. Adjacent to the standoff 40 is an insulator tube 57 that surrounds the bare wire lead 53 and terminates at the terminal (not shown). Although not shown, the wire lead of other coiled portion positioned beneath frame 59 extends through the other slot 49 in the standoff and the other insulator tube 57 in route to the terminal block. The straight wire lead 53 is one end of the electric resistance element used in one stage of the two stage heater, akin to element 10b of FIG. 1 and its wire lead 32. As is evident from FIG. 1, the element 10b furthest removed from the terminal block 28 has the longest runs of uncoiled wire leads, with the pair of wire leads for the heating element disposed on either side of the frame. In these types of heaters and as noted above, the standoff 40 has opposing slots 49 to support each uncoiled wire lead of the heating element, one on either side of the frame 59. When using the standoff to support bare wire leads that also use insulation such as the tubes 57 shown in FIG. 3, the exposed portion of the wire lead is further minimized by the insulating coverage provided by the slot 49. While FIG. 3 shows the standoff 40 supporting bare wire leads adjacent to wire lead encased in an insulator tube, the standoff 40 could be used to support one, or a pair of bare wire leads that are not insulated at all. As mentioned above, the standoff could also support the insulated wire lead rather than the bare wire lead, with the slot or slots sized appropriately to accommodate the insulation. Also, the standoff could be used in heaters that would employ only one run of bare lead wire, such that only one slot would be needed for wire lead support. FIG. 3 also illustrates a crossover 65 which links the coil portion 56 to another coiled portion disposed on the other side of the frame 59 as part of the other element of the two elements making up the two stage heater. The standoff is made from electrically insulating material, and can be virtually any type that would achieve this insulating purpose. Preferred materials are ceramic materials, similar to the materials used as support insulators for the coils of the heaters as described in the Tutco patents mentioned above. The standoffs can be made in any known manner. The standoff embodiment of FIGS. 2 and 3 also includes means for mounting the standoff 40 to the frame 59 of a heater, the frame 59 being similar to the frame 14 shown in FIG. 1. It should be understood that the means for mounting the standoff 40 onto a frame as described below is but one embodiment of the invention, and alternatives as detailed below also fall within the scope of the invention. In one preferred mode, the standoff 40 is configured with slots to engage a specially configured metal frame to keep it in place. Turning to FIGS. 4 and 5, FIG. 4 shows a larger segment of the frame shown in FIG. 3 and FIG. 5 shows an enlarged part of the frame of FIG. 4. The frame 59 has a pair of cutouts 71 and 73. The frame 59 also depicts cutouts 78, which allow for mounting of the support insulators for coil retention, and a cutout 82 for terminal block mounting. Since the manner in which the support insulators and terminal block are mounted to the frame is well known, a further description of this aspect of the frame is not deemed necessary for understanding of the invention. The cutout 71 serves two purposes; it allows for mounting of the standoff 40 and creates a space for the crossover portion of the heating element. Cutout 73 does not require a crossover and needs to be sized just to allow the standoff to be mounted to the frame 59. Each of the cutouts 71, 73 is configured the same for mounting of the standoff. Referring to FIG. 5, cutout 71 includes an entry zone 75 that allows the standoff to be first inserted into the cutout. One recess 77 is intended to receive an end of the standoff, with the recess forming an edge 79. Referring now to FIGS. 2 and 5, the standoff body 41 has a slot 81, which is sized to engage the frame portion outlined at 83 (see FIG. 5). The standoff 40 includes another slot 85 opposed to slot 81 for attachment to another part of the frame 59 as detailed below. When the standoff 40 is positioned within the cutout 73 for entry through zone 75, the standoff end containing the slot 81 is guided into the recess 77 such that the slot 81 is engaged by the frame portion 83. The standoff 40 is then rotated so that the slot 85 passes over tab 87 and frame portion outlined as 89. The sidewall of the standoff eventually contacts the edge 88 of the cutout 73, causing the standoff to come to rest. The tab 87 is then bent upward or downward, see FIG. 2 for an upward bend, to prevent the standoff slot 85 from being disengaged from frame portion 89. Turning back to the slot 81, the recess 77 in the frame 59 and the slot 81 in the opposite end of the standoff 40 are sized so that the slot 81 engages sufficient frame to hold it in place The recess 77 is also sized so that its edge 79 abuts a portion of the sidewall of the standoff body 41, outlined as 91 in FIG. 2. This abutting engagement between the edge 79 and sidewall portion 91 keeps the standoff from rotating or moving once the slot 81 engages the frame portion 83. To remove the standoff 40, the tab 87 would first be realigned with the plane of the frame 59. The standoff 40 can then be turned such that the slot 85 can be disengaged from frame portion 89, and the slot 81 can be disengaged from frame portion 83. While the manner in which the standoff is mounted to the frame is only described for cutout 73, it should be understood that the same mounting arrangement and technique is employed for cutout 71. Further, while the frame 59 shows two cutouts for supporting the wire lead of a heating element, the heater could be the type wherein only one cutout and one standoff are required. Alternatively, the run or runs of the wire lead may be such that more than two cutouts and standoffs are required. As part of the standoff mounting, the wire leads 53, see FIG. 3, are preferably first inserted into the opposing slots 49 prior to mounting of the standoff 40 to the frame 59. In this regard, cutout 73 is provided with an ample opening so that there is sufficient room to maneuver the standoff in a position to engage the wire lead 53 and slot 49 without having to move the wire lead any substantial distance for slot engagement. While the standoff is shown mounted to the frame using a particular cutout configuration in the frame, and slots in the standoff body, other ways as would be within the skill of the art could be employed to mount the standoff to the frame. For example, the standoff could be mounted with fasteners, other shaped slotted arrangements, adhesives, snap fittings, or one or more combinations of these techniques. In one mode, the standoff could be formed with flanges instead of slots, wherein the flanges would extend from the standoff body. Fasteners such as screws or rivets, adhesives, or other attaching techniques could be employed to secure the flanges to the frame, with the flanges configured appropriately depending on the mounting technique, e.g., fasteners with preformed throughholes when using fasteners. It should also be understood that the standoff 40 of FIG. 2 is designed to support a wire lead on both sides of the frame 59 since a pair of L-shaped arms 43 are utilized. In this mode, and referring back to FIG. 1, such a standoff would be used to support each of wire leads 32 and 34. However, in other instances, the standoff could be made with only one slot 49 with the body sized to still retain slots 81 and 85 for mounting purposes, but without the other L-shaped arm. FIG. 6 shows this embodiment by reference numeral 40′ wherein the standoff body 41′ is sized to accommodate the slots 81 and 85 without the need for the presence of the other L-shaped arm 43. The standoff mounting arrangement described in FIGS. 3-5 is intended for a two-stage heater such as that disclosed in U.S. Pat. No. 5,925,273, but it is not so limited. That is, the standoff could be used in a single stage open coil heater wherein the wire lead extending between the coil and the terminal connection for one heating element, bare or insulated, require support, or any other heater that would have excessive runs of wire leads that require support. While the invention has been described to support the uncoiled portions of the resistance wire heating element that functioned as the wire leads, the standoff can be used to support other uncoiled wire runs of a heater. A particular heater may have a run of wire that does not terminate at a terminal block or like, but still needs support for the length of the run. In this situation, the standoff could be mounted to the frame in such a position that its slot can support the uncoiled wire run. The run may involve a lengthy crossover that may need support to prevent shorting or a run between adjacent coils. FIG. 7 illustrates an example wherein a pair of coils, 101 and 103, are mounted on a frame (mounting not shown), with a run of uncoiled wire 105 extending between the coil. Because of the configuration of the heater, the run 105 requires support and a standoff 107 is used to support the run 105 via slot 109. The standoff can be mounted to the frame (not shown) in any of the manners described above. As noted above, the method of heating using the inventive standoff in a heater can include methods wherein the wire resistance element is used in forced convection heating that employs air as the convective fluid passing over the wire. Alternatively, the resistance wire element can be used for radiant heating or free or natural convection heating. As such, an invention has been disclosed in terms of preferred embodiments thereof which fulfills each and every one of the objects of the present invention as set forth above and provides a new and improved standoff-containing open coil resistance heater, the standoff itself, and a method of heating. Of course, various changes, modifications and alterations from the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention only be limited by the terms of the appended claims.
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<SOH> BACKGROUND ART <EOH>The use of a single resistance wire formed into a helical coil for use in electric resistance heating either for heating moving air, for radiant heating or for convection heating is well known in the prior art. In one type of heater, the resistance coils are energized to heat air passing over the coils, the heated air then being directed in a particular manner for heating purposes. One application using such a heater is an electric clothes dryer. Examples of open coil heaters are found in U.S. Pat. Nos. 5,329,098, 5,895,597, and 5,925,273, all owned by Tutco, Inc. of Cookeville, Tenn. Each of these patents is incorporated by reference in its entirety herein. One type of an open coil electric resistance heater is a two stage heater described in U.S. Pat. No. 5,925,273. A side view of this type of heater is shown in FIG. 1 and designated by the reference numeral 10 . The heater 10 has two heater elements 10 a and 10 b , optimally for use in a clothes dryer. The elements 10 a and 10 b are supplied with electricity via terminals 12 extending from the terminal block 28 . The heater elements 10 a , 10 b are supported by a metal plate 14 , which in turn supports a plurality of support insulators 16 , which are well known in the art. The support insulators 16 support and isolate coiled portions of the elements, 10 a and 10 b , during operation of the heater. The heater 10 includes opposing sidewalls (one shown as 6 in FIG. 1 ), wherein projections in the plate 14 extend through slots 20 in the sidewall 6 to allow the sidewalls to support the plate. Each of the electric heater elements, 10 a and 10 b , is arranged in series of electrically continuous coils which are mounted on the plate 14 in a spaced-apart substantially parallel arrangement. Each heater assembly 10 a and 10 b is arranged substantially equally and oppositely on both sides of the plate. Crossover portions 22 a and 22 b of each heater element 10 a and 10 b are provided wherein each crossover links one coil of each of the elements mounted on one side of the plate 14 with another coil of the same element found on the other side of the plate. The plate 14 has several cutout portions (not shown) to provide adequate clearance for the crossover portions, 22 a and 22 b , and the anticipated drooping or sagging movement of such portions. Electricity is supplied to the heater assembly through the terminal block 28 . The heater elements, 10 a and 10 b , are arranged so that the terminal connector portions or wire leads 32 and 34 which extend from an end 38 of each of the mounted coil sections to the terminal block are as short as possible. This aids in eliminating or reducing the need for supporting the connector portions. For the longer runs, the wire leads, 32 and 34 , are partially enclosed with an insulating member 36 . The insulating member 36 may be formed from any type of insulating material suitable for this purpose, e.g., a ceramic type. The insulating member is generally tubular in shape and rigid. One of the most significant aspects of the open coil heater design is that of routing the uncoiled connector portions extending from the ends of heater coils (resistance wire leads) so they are protected from contact with either adjacent live heater wire sections or from contact with bare metal, either of which creates a potential failure. The resistance wire leads for connecting to the termination point(s) for ultimate connection to a source of electrical power must therefore be routed and protected from dead metal and from electrically live parts of a different polarity than the resistance wire leads. When physical separation cannot be achieved using design techniques available to the technology, the prior art, as noted above, has used insulating tubes made of appropriate materials for the application, e.g., ceramic tubes are used for routing and isolating the resistance wires lead, see items 36 in FIG. 1 . However, the mere use of ceramic tubes alone to protect the resistance wire leads does not always solve all of the problems in these types of heaters. The manufacturing of open coil heaters that use insulating tubes to protect a length of bare resistance wire lead section often requires more than one tube section for each wire lead. That is, to span longer sections it is necessary to use multiple tube pieces. At the point where two tubes meet there is, of course, a narrow opening and when electrical spacing requirements per safety standards are considered, the opening can be or is significant. The same condition may exist at the free end of a ceramic tube, i.e. where there is no adjacent tube. Even under the best of conditions there are over-the-surface and through-the-air distance conditions occurring where an electric potential exists. This electrical potential could result in either a ground out or an electrical short should movement occur, both of which are dangerous conditions to be avoided. There are practical reasons why multiple tubes may be required to span one section of bare resistance wire. The first is that longer sections of insulating tubes are more expensive to manufacture than shorter sections, so that using a number of shorter sections may be more economical. Another reason that longer tubes are shunned is that shipping and handling relatively long tubes during heater assembly result in damage or breakage. Further it is often more economical to have available multiple short pieces that are of a lower cost per unit length in order to accommodate various length requirements than to have exact lengths made for every requirement. A given length requirement can be fulfilled by using two or more short pieces of insulating tubes to span the longer required distance. Even when a single insulating tube is of sufficient length to span the distance from the end of the heating coil to the termination point, there may be lack of clearance at a tube end between the wire exiting the tube and adjacent dead metal. A further problem results should a tube break and the result is another potential electrical short or ground out condition being created. It is also impractical to use an insulating tube with a wall thickness great enough to overcome the dangerous electrical conditions noted above. Thick walled tubes are costly to produce and handle during the manufacture of open coil heaters. In the art of open coil heaters, separate tabs, clips, straps or stand-offs made of metal have been used to position and permanently restrain the insulating tubes containing resistance wires as described above. However, this method of restraint often creates mechanical stress resulting in tube breakage. Though a break in the tube in itself doesn't mean the wires will move from their intended routing, a possible electrical short or a ground condition may result as an effect of the wire contacting the above described metal restraining means. In light of the shortcomings in protecting the bare wire leads or the problems when using ceramic leads of open coil electric resistance heaters, a need has developed for improved ways to minimize the possibility of shorting or grounding conditions. The present invention responds to this need by providing a standoff for use with the resistance wire leads or other uncoiled runs to minimize these grounding/shorting conditions.
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<SOH> SUMMARY OF THE INVENTION <EOH>It is a first object of the invention to provide an improved open coil resistance heater. It is another object of the invention to provide an open coil resistance heater that uses one or more standoffs that support uncoiled wire runs, particularly wire leads of the heater. Yet another object of the invention is a standoff for use with an open coil heater or other type of heater whereby the standoff can engage wire runs, particularly wire leads, of the heater to protect them from shorting/grounding in the run. One further object of the invention is an improvement in methods of providing heat using electric resistance heaters, wherein the heater includes one or more standoffs for the heater's uncoiled wire, particularly wire leads, to minimize shorting or grounding conditions. Other objects and advantages will become apparent as a description of the invention proceeds. In satisfaction of the foregoing objects and advantages of the invention, the invention is an improvement in heaters employing open coil electric resistance elements. More particularly, the invention involves heaters that contain one or more runs of uncoiled or generally straight wire runs. A given run may extend between two coiled portions of the heater element. Alternatively, the run may extend between the coiled portion of the heating element and a terminal block or the like that is adapted for connection to a source of power, this run forming a wire lead to assist connecting the resistance wire to a supply of power. The coiled portion of the resistance wire element is supported by a plurality of insulators, with the plurality of insulators being supported by a frame. The invention is the use of one or more standoffs that are made of electrically insulating material. Each standoff further comprises a standoff body including means for mounting the body to the frame. Each standoff body has at least one slot sized to engage and support a portion of the run of uncoiled wire, either in a bare state or in an insulated state. If the heater employs a pair of runs that require support, the standoff body can be configured to have a pair of slots to accommodate the pair of wire runs. The slots can be sized to support either bare wire or insulated wire. The standoff is especially adapted for two stage heaters, wherein the heating element most remote from the terminal block has long runs of wire that can use one or more standoffs for support. In one embodiment, the standoff can be used with insulated wire leads wherein the insulation is positioned adjacent the standoff such that the standoff is supporting a bare wire run and offering an insulating effect on the bare wire run as well. The means for mounting the standoff can involve any number of mounting configurations from fasteners, to specially configured slots in the heater frame, to adhesives or combinations thereof. In one mode, the mounting means comprises a pair of opposing slots in the standoff body, and a cutout in the frame. Each slot engages a respective portion of the frame adjacent the cutout for mounting, a portion of the frame including a tab adjacent to one of the respective portions of the frame. To secure the standoff, the tab can be bent to retain the standoff in the cutout. Depending on the length of the uncoiled wire run, more than one cutout and standoff can be utilized for wire run support. The cutout can be shaped to allow for rotation of the standoff for mounting purposes, and/or sized to allow for both standoff rotation and crossover wire passage to link coils on opposite sides of the frame. The invention also entails an improvement in a method of heating using an open coil electric resistance heater, wherein the heater has at least one resistance wire element for heating, a coiled portion of the resistance wire element being supported by a plurality of insulators, with the plurality of insulators being supported by a frame, the wire element including one or more uncoiled wire runs that require support. The run or runs can be the uncoiled bare or insulated wire leads beginning at coiled portions of the wire element and terminating in a pair of uncoiled bare wire leads for connection to a source of power via a terminal mounted to the heater. As noted above, the uncoiled runs, bare or insulated can also extend between two coiled portions of the resistance wire element. As part of this method, at least one resistance wire element is energized to generate heat, either via radiation or convection. The improvement in the method comprises supporting the bare or insulated wire runs using at least one standoff made of the electrically insulating material that is mounted to the frame and positioned so as to support one or more uncoiled wire runs.
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20040630
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20060711
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20060105
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68386.0
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H05B306
| 0
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PATEL, VINOD D
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STANDOFF FOR USE WITH UNCOILED BARE WIRE AND INSULATED RUNS OF AN OPEN COIL ELECTRIC RESISTANCE HEATER, METHOD OF USE, AND AN OPEN COIL RESISTANCE HEATER USING THE STANDOFF
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UNDISCOUNTED
| 0
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ACCEPTED
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H05B
| 2,004
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10,879,335
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ACCEPTED
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Methods for driving electro-optic displays
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An electro-optic display, having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states, is driven by displaying a first image on the display, and rewriting the display to display a second image thereon, wherein, during the rewriting of the display, any pixel which has undergone a number of transitions exceeding a predetermined value without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image.
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1. A method for driving an electro-optic display having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states, the method comprising: displaying a first image on the display; and rewriting the display to display a second image thereon, wherein, during the rewriting of the display any pixel which has undergone a number of transitions exceeding a predetermined value, the predetermined value being at least one, without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image. 2. A method according to claim 1 wherein the rewriting of the display is effected such that, once a pixel has been driven from one extreme optical state towards the opposed extreme optical state by a pulse of one polarity, the pixel does not receive a pulse of the opposed polarity until it has reached the opposed extreme optical state. 3. A method according to claim 1 wherein said predetermined value is not greater than N/2, where N is the total number of gray levels capable of being displayed by a pixel. 4. A method according to claim 1 wherein the rewriting of the display is effected by applying to the or each pixel any one or more of voltages −V, 0 and +V. 5. A method according to claim 1 wherein the rewriting of the display is effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded. 6. A method according to claim 1 wherein the rewriting of the display is effected such that the impulse applied to a pixel during a transition depends only upon the initial and final gray levels of that transition. 7. A method according to claim 1 wherein, for at least one transition undergone by the at least one pixel from a gray level R2 to a gray level R1, there is applied to the pixel a sequence of impulses of the form: −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) where “IP(Rx)” represents the relevant value from an impulse potential matrix having one value for each gray level, and TM(R1,R2) represents the relevant value from a transition matrix having one value for each R1/R2 combination. 8. A method according to claim 7 wherein for all transitions in which the initial and final gray levels are different, the sequence of impulses of the form: −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2). 9. A method according to claim 7 wherein, in the −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) sequence, the final TM(R1,R2) section occupies more than one half of the maximum update time. 10. A method according to claim 1 wherein the rewriting of the display is effected such that a transition to a given gray level is always effected by a final pulse of the same polarity. 11. A method according to claim 10 wherein gray levels other than the two extreme optical states are approached from the direction of the nearer extreme optical state. 12. A method according to claim 7 wherein the TM(R1,R2) values are chosen such that the sign of each value is dependent only upon R1. 13. A method according to claim 12 wherein the TM(R1,R2) values are chosen to be positive for one or more light gray levels and negative for one or more dark gray levels so that gray levels other than the two extreme optical states are approached from the direction of the nearer extreme optical state. 14. A method according to claim 7 wherein the at least one transition further comprises an additional pair of pulses of the form [+y][−y], where y is an impulse value, which may be either negative or positive, the [+y] and [−y] pulses being inserted into the −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) sequence. 15. A method according to claim 14 wherein the at least one transition further comprises a second additional pair of pulses of the form [+z][−z], where z is an impulse value different from y and may be either negative or positive, the [+z] and [−z] pulses being inserted into the −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) sequence. 16. A method according to claim 7 wherein the at least one transition further comprises a period when no voltage is applied to the pixel. 17. A method according to claim 16 wherein the period when no voltage is applied to the pixel occurs between two elements of the −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) sequence. 18. A method according to claim 16 wherein the period when no voltage is applied to the pixel occurs between at an intermediate point within a single element of the −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) sequence. 19. A method according to claim 16 wherein the at least one transition comprise at least two periods when no voltage is applied to the pixel. 20. A method according to claim 7 wherein the display comprises a plurality of pixels divided into a plurality of groups, and the transition is effected by (a) selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period; (b) repeating the scanning of the groups of pixels during a second frame period; and (c) interrupting the scanning of the groups of pixels during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. 21. A method according to claim 1 wherein the electro-optic display comprises an electrochromic or rotating bichromal member electro-optic medium. 22. A method according to claim 1 wherein the electro-optic display comprises an encapsulated electrophoretic medium. 23. A method according to claim 1 wherein the electro-optic display comprises a microcell electrophoretic medium. 24. A method for driving an electro-optic display having a plurality of pixels divided into a plurality of groups, the method comprising: (a) selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period; (b) repeating the scanning of the groups of pixels during a second frame period; and (c) interrupting the scanning of the groups of pixels during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. 25. A method according to claim 24 wherein the first and second frame periods are equal in length. 26. A method according to claim 25 wherein the length of the pause period is a sub-multiple of the length of one of the first and second frame periods. 27. A method according to claim 24 wherein the method comprises scanning the groups of pixels during at least first, second and third frame periods, and interrupting the scanning of the groups of pixels during at least first and second pause periods between successive frame periods. 28. A method according to claim 27 wherein the first, second and third frame periods are substantially equal in length, and the total length of the pause periods is equal to one frame period or one frame period minus one pause period. 29. A method according to claim 24 wherein the pixels are arranged in a matrix having a plurality of rows and a plurality of columns with each pixel defined by the intersection of a given row and a given column, and wherein each group of pixels comprises one row or one column of the matrix. 30. A method according to claim 24 wherein the scanning of the display is effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded. 31. A method according to claim 24 wherein the electro-optic display comprises an electrochromic or rotating bichromal member electro-optic medium. 32. A method according to claim 24 wherein the electro-optic display comprises an encapsulated electrophoretic medium. 33. A method according to claim 24 wherein the electro-optic display comprises a microcell electrophoretic medium. 34. A method for driving an electro-optic display having a plurality of pixels, the pixels being driven with a pulse width modulated waveform capable of applying a plurality of differing impulses to each pixel, the method comprising: (a) storing data indicating whether application of a given impulse to a pixel will produce a gray level higher or lower than a desired gray level; (b) detecting when two adjacent pixels are both required to be in the same gray level; and (c) adjusting the impulses applied to the two pixels so that one pixel is below the desired gray level, while the other pixel is above the desired gray level. 35. A method according to claim 34 wherein the pixels are divided into two groups such that each pixel has at least one neighbor of the opposite group, and different drive schemes are used for the two groups. 36. A method according to claim 34 wherein the electro-optic display comprises an electrochromic or rotating bichromal member electro-optic medium. 37. A method according to claim 34 wherein the electro-optic display comprises an encapsulated electrophoretic medium. 38. A method according to claim 34 wherein the electro-optic display comprises a microcell electrophoretic medium.
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REFERENCE TO RELATED APPLICATIONS This application claims benefit of the following Provisional Applications: (a) Ser. No. 60/481,040, filed Jun. 30, 2003; (b) Ser. No. 60/481,053, filed Jul. 2, 2003; and (c) Ser. No. 60/481,405, filed Sep. 22, 2003. This application is also a continuation-in-part of copending application Ser. No. 10/814,205, filed Mar. 31, 2004, which itself claims benefit of the following Provisional Applications: (d) Ser. No. 60/320,070, filed Mar. 31, 2003; (e) Ser. No. 60/320,207, filed May 5, 2003; (f) Ser. No. 60/481,669, filed Nov. 19, 2003; (g) Ser. No. 60/481,675, filed Nov. 20, 2003; and (h) Ser. No. 60/557,094, filed Mar. 26, 2004. The aforementioned copending application Ser. No. 10/814,205 is also a continuation-in-part of copending application Ser. No. 10/065,795, filed Nov. 20, 2002 (Publication No. 2003/0137521), which itself claims benefit of the following Provisional Applications: (i) Ser. No. 60/319,007, filed Nov. 20, 2001; (j) Ser. No. 60/319,010, filed Nov. 21, 2001; (k) Ser. No. 60/319,034, filed Dec. 18, 2001; (l) Ser. No. 60/319,037, filed Dec. 20, 2001; and (m) Ser. No. 60/319,040, filed Dec. 21, 2001. This application is also related to application Ser. No. 10/249,973, filed May 23, 2003, which is a continuation-in-part of the aforementioned application Ser. No. 10/065,795. application Ser. No. 10/249,973 claims priority from Provisional Applications Ser. No. 60/319,315, filed Jun. 13, 2002 and Ser. No. 60/319,321, filed Jun. 18, 2002. This application is also related to copending application Ser. No. 10/063,236, filed Apr. 2, 2002 (Publication No. 2002/0180687). The entire contents of these copending applications, and of all other U.S. patents and published and copending applications mentioned below, are herein incorporated by reference. BACKGROUND OF INVENTION This invention relates to methods for driving electro-optic displays. The methods of the present invention are especially, though not exclusively, intended for use in driving bistable electrophoretic displays. The term “electro-optic” as applied to a material or a display, is used herein in its conventional meaning in the imaging art to refer to a material having first and second display states differing in at least one optical property, the material being changed from its first to its second display state by application of an electric field to the material. Although the optical property is typically color perceptible to the human eye, it may be another optical property, such as optical transmission, reflectance, luminescence or, in the case of displays intended for machine reading, pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range. The term “gray state” is used herein in its conventional meaning in the imaging art to refer to a state intermediate two extreme optical states of a pixel, and does not necessarily imply a black-white transition between these two extreme states. For example, several of the patents and published applications referred to below describe electrophoretic displays in which the extreme states are white and deep blue, so that an intermediate “gray state” would actually be pale blue. Indeed, as already mentioned the transition between the two extreme states may not be a color change at all. The terms “bistable” and “bistability” are used herein in their conventional meaning in the imaging art to refer to displays comprising display elements having first and second display states differing in at least one optical property, and such that after any given element has been driven, by means of an addressing pulse of finite duration, to assume either its first or second display state, after the addressing pulse has terminated, that state will persist for at least several times, for example at least four times, the minimum duration of the addressing pulse required to change the state of the display element. It is shown in published U.S. patent application No. 2002/0180687 that some particle-based electrophoretic displays capable of gray scale are stable not only in their extreme black and white states but also in their intermediate gray states, and the same is true of some other types of electro-optic displays. This type of display is properly called “multi-stable” rather than bistable, although for convenience the term “bistable” may be used herein to cover both bistable and multi-stable displays. The term “impulse” is used herein in its conventional meaning in the imaging art of the integral of voltage with respect to time. However, some bistable electro-optic media act as charge transducers, and with such media an alternative definition of impulse, namely the integral of current over time (which is equal to the total charge applied) may be used. The appropriate definition of impulse should be used, depending on whether the medium acts as a voltage-time impulse transducer or a charge impulse transducer. Several types of electro-optic displays are known. One type of electro-optic display is a rotating bichromal member type as described, for example, in U.S. Pat. Nos. 5,808,783; 5,777,782; 5,760,761; 6,054,071 6,055,091; 6,097,531; 6,128,124; 6,137,467; and 6,147,791 (although this type of display is often referred to as a “rotating bichromal ball” display, the term “rotating bichromal member” is preferred as more accurate since in some of the patents mentioned above the rotating members are not spherical). Such a display uses a large number of small bodies (typically spherical or cylindrical) which have two or more sections with differing optical characteristics, and an internal dipole. These bodies are suspended within liquid-filled vacuoles within a matrix, the vacuoles being filled with liquid so that the bodies are free to rotate. The appearance of the display is changed to applying an electric field thereto, thus rotating the bodies to various positions and varying which of the sections of the bodies is seen through a viewing surface. This type of electro-optic medium is typically bistable. Another type of electro-optic display uses an electrochromic medium, for example an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least in part from a semi-conducting metal oxide and a plurality of dye molecules capable of reversible color change attached to the electrode; see, for example O'Regan, B., et al., Nature 1991, 353, 737; and Wood, D., Information Display, 18(3), 24 (March 2002). See also Bach, U., et al., Adv. Mater., 2002, 14(11), 845. Nanochromic films of this type are also described, for example, in U.S. Pat. No. 6,301,038, International Application Publication No. WO 01/27690, and in U.S. patent application 2003/0214695. This type of medium is also typically bistable. Another type of electro-optic display, which has been the subject of intense research and development for a number of years, is the particle-based electrophoretic display, in which a plurality of charged particles move through a suspending fluid under the influence of an electric field. Electrophoretic displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption when compared with liquid crystal displays. Nevertheless, problems with the long-term image quality of these displays have prevented their widespread usage. For example, particles that make up electrophoretic displays tend to settle, resulting in inadequate service-life for these displays. Numerous patents and applications assigned to or in the names of the Massachusetts Institute of Technology (MIT) and E Ink Corporation have recently been published describing encapsulated electrophoretic media. Such encapsulated media comprise numerous small capsules, each of which itself comprises an internal phase containing electrophoretically-mobile particles suspended in a liquid suspending medium, and a capsule wall surrounding the internal phase. Typically, the capsules are themselves held within a polymeric binder to form a coherent layer positioned between two electrodes. Encapsulated media of this type are described, for example, in U.S. Pat. Nos. 5,930,026; 5,961,804; 6,017,584; 6,067,185; 6,118,426; 6,120,588; 6,120,839; 6,124,851; 6,130,773; 6,130,774; 6,172,798; 6,177,921; 6,232,950; 6,249,721; 6,252,564; 6,262,706; 6,262,833; 6,300,932; 6,312,304; 6,312,971; 6,323,989; 6,327,072; 6,376,828; 6,377,387; 6,392,785; 6,392,786; 6,413,790; 6,422,687; 6,445,374; 6,445,489; 6,459,418; 6,473,072; 6,480,182; 6,498,114; 6,504,524; 6,506,438; 6,512,354; 6,515,649; 6,518,949; 6,521,489; 6,531,997; 6,535,197; 6,538,801; 6,545,291; 6,580,545; 6,639,578; 6,652,075; 6,657,772; 6,664,944; 6,680,725; 6,683,333; 6,704,133; 6,710,540; 6,721,083; 6,724,519; and 6,727,881; and U.S. Patent Applications Publication Nos. 2002/0019081; 2002/0021270; 2002/0053900; 2002/0060321; 2002/0063661; 2002/0063677; 2002/0090980; 2002/0106847; 2002/0113770; 2002/0130832; 2002/0131147; 2002/0145792; 2002/0171910; 2002/0180687; 2002/0180688; 2002/0185378; 2003/0011560; 2003/0011868; 2003/0020844; 2003/0025855; 2003/0034949; 2003/0038755; 2003/0053189; 2003/0102858; 2003/0132908; 2003/0137521; 2003/0137717; 2003/0151702; 2003/0189749; 2003/0214695; 2003/0214697; 2003/0222315; 2004/0008398; 2004/0012839; 2004/0014265; 2004/0027327; 2004/0075634; and 2004/0094422; and International Applications Publication Nos. WO 99/67678; WO 00/05704; WO 00/38000; WO 00/38001; WO00/36560; WO 00/67110; WO 00/67327; WO 01/07961; WO 01/08241; WO 03/092077; WO 03/107315; WO 2004/017035; and WO 2004/023202. Many of the aforementioned patents and applications recognize that the walls surrounding the discrete microcapsules in an encapsulated electrophoretic medium could be replaced by a continuous phase, thus producing a so-called “polymer-dispersed electrophoretic display” in which the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be regarded as capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet; see for example, the aforementioned 2002/0131147. Accordingly, for purposes of the present application, such polymer-dispersed electrophoretic media are regarded as sub-species of encapsulated electrophoretic media. An encapsulated electrophoretic display typically does not suffer from the clustering and settling failure mode of traditional electrophoretic devices and provides further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates. (Use of the word “printing” is intended to include all forms of printing and coating, including, but without limitation: pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; ink jet printing processes; and other similar techniques.) Thus, the resulting display can be flexible. Further, because the display medium can be printed (using a variety of methods), the display itself can be made inexpensively. A related type of electrophoretic display is a so-called “microcell electrophoretic display”. In a microcell electrophoretic display, the charged particles and the suspending fluid are not encapsulated within capsules but instead are retained within a plurality of cavities formed within a carrier medium, typically a polymeric film. See, for example, International Application Publication No. WO 02/01281, and U.S. Patent Application Publication No. 2002/0075556, both assigned to Sipix Imaging, Inc. Although electrophoretic media are often opaque (since, for example, in many electrophoretic media, the particles substantially block transmission of visible light through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in a so-called “shutter mode” in which one display state is substantially opaque and one is light-transmissive. See, for example, the aforementioned U.S. Pat. Nos. 6,130,774 and 6,172,798, and U.S. Pat. Nos. 5,872,552; 6,144,361; 6,271,823; 6,225,971; and 6,184,856. Dielectrophoretic displays, which are similar to electrophoretic displays but rely upon variations in electric field strength, can operate in a similar mode; see U.S. Pat. No. 4,418,346. Other types of electro-optic displays may also be capable of operating in shutter mode. The bistable or multi-stable behavior of particle-based electrophoretic displays, and other electro-optic displays displaying similar behavior (such displays may hereinafter for convenience be referred to as “impulse driven displays”), is in marked contrast to that of conventional liquid crystal (“LC”) displays. Twisted nematic liquid crystals act are not bi- or multi-stable but act as voltage transducers, so that applying a given electric field to a pixel of such a display produces a specific gray level at the pixel, regardless of the gray level previously present at the pixel. Furthermore, LC displays are only driven in one direction (from non-transmissive or “dark” to transmissive or “light”), the reverse transition from a lighter state to a darker one being effected by reducing or eliminating the electric field. Finally, the gray level of a pixel of an LC display is not sensitive to the polarity of the electric field, only to its magnitude, and indeed for technical reasons commercial LC displays usually reverse the polarity of the driving field at frequent intervals. In contrast, bistable electro-optic displays act, to a first approximation, as impulse transducers, so that the final state of a pixel depends not only upon the electric field applied and the time for which this field is applied, but also upon the state of the pixel prior to the application of the electric field. Whether or not the electro-optic medium used is bistable, to obtain a high-resolution display, individual pixels of a display must be addressable without interference from adjacent pixels. One way to achieve this objective is to provide an array of non-linear elements, such as transistors or diodes, with at least one non-linear element associated with each pixel, to produce an “active matrix” display. An addressing or pixel electrode, which addresses one pixel, is connected to an appropriate voltage source through the associated non-linear element. Typically, when the non-linear element is a transistor, the pixel electrode is connected to the drain of the transistor, and this arrangement will be assumed in the following description, although it is essentially arbitrary and the pixel electrode could be connected to the source of the transistor. Conventionally, in high resolution arrays, the pixels are arranged in a two-dimensional array of rows and columns, such that any specific pixel is uniquely defined by the intersection of one specified row and one specified column. The sources of all the transistors in each column are connected to a single column electrode, while the gates of all the transistors in each row are connected to a single row electrode; again the assignment of sources to rows and gates to columns is conventional but essentially arbitrary, and could be reversed if desired. The row electrodes are connected to a row driver, which essentially ensures that at any given moment only one row is selected, i.e., that there is applied to the selected row electrode a voltage such as to ensure that all the transistors in the selected row are conductive, while there is applied to all other rows a voltage such as to ensure that all the transistors in these non-selected rows remain non-conductive. The column electrodes are connected to column drivers, which place upon the various column electrodes voltages selected to drive the pixels in the selected row to their desired optical states. (The aforementioned voltages are relative to a common front electrode which is conventionally provided on the opposed side of the electro-optic medium from the non-linear array and extends across the whole display.) After a pre-selected interval known as the “line address time” the selected row is deselected, the next row is selected, and the voltages on the column drivers are changed to that the next line of the display is written. This process is repeated so that the entire display is written in a row-by-row manner. It might at first appear that the ideal method for addressing such an impulse-driven electro-optic display would be so-called “general grayscale image flow” in which a controller arranges each writing of an image so that each pixel transitions directly from its initial gray level to its final gray level. However, inevitably there is some error in writing images on an impulse-driven display. Some such errors encountered in practice include: (a) Prior State Dependence; With at least some electro-optic media, the impulse required to switch a pixel to a new optical state depends not only on the current and desired optical state, but also on the previous optical states of the pixel. (b) Dwell Time Dependence; With at least some electro-optic media, the impulse required to switch a pixel to a new optical state depends on the time that the pixel has spent in its various optical states. The precise nature of this dependence is not well understood, but in general, more impulse is required that longer the pixel has been in its current optical state. (c) Temperature Dependence; The impulse required to switch a pixel to a new optical state depends heavily on temperature. (d) Humidity Dependence; The impulse required to switch a pixel to a new optical state depends, with at least some types of electro-optic media, on the ambient humidity. (e) Mechanical Uniformity; The impulse required to switch a pixel to a new optical state may be affected by mechanical variations in the display, for example variations in the thickness of an electro-optic medium or an associated lamination adhesive. Other types of mechanical non-uniformity may arise from inevitable variations between different manufacturing batches of medium, manufacturing tolerances and materials variations. (f) Voltage Errors; The actual impulse applied to a pixel will inevitably differ slightly from that theoretically applied because of unavoidable slight errors in the voltages delivered by drivers. General grayscale image flow suffers from an “accumulation of errors” phenomenon. For example, imagine that temperature dependence results in a 0.2 L* (where L* has the usual CIE definition: L*=116(R/R0)1/3−16 where R is the reflectance and R0 is a standard reflectance value) error in the positive direction on each transition. After fifty transitions, this error will accumulate to 10 L*. Perhaps more realistically, suppose that the average error on each transition, expressed in terms of the difference between the theoretical and the actual reflectance of the display is ±0.2 L*. After 100 successive transitions, the pixels will display an average deviation from their expected state of 2 L*; such deviations are apparent to the average observer on certain types of images. This accumulation of errors phenomenon applies not only to errors due to temperature, but also to errors of all the types listed above. As described in the aforementioned 2003/0137521, compensating for such errors is possible, but only to a limited degree of precision. For example, temperature errors can be compensated by using a temperature sensor and a lookup table, but the temperature sensor has a limited resolution and may read a temperature slightly different from that of the electro-optic medium. Similarly, prior state dependence can be compensated by storing the prior states and using a multi-dimensional transition matrix, but controller memory limits the number of states that can be recorded and the size of the transition matrix that can be stored, placing a limit on the precision of this type of compensation. Thus, general grayscale image flow requires very precise control of applied impulse to give good results, and empirically it has been found that, in the present state of the technology of electro-optic displays, general grayscale image flow is infeasible in a commercial display. Almost all electro-optic medium have a built-in resetting (error limiting) mechanism, namely their extreme (typically black and white) optical states, which function as “optical rails”. After a specific impulse has been applied to a pixel of an electro-optic display, that pixel cannot get any whiter (or blacker). For example, in an encapsulated electrophoretic display, after a specific impulse has been applied, all the electrophoretic particles are forced against one another or against the capsule wall, and cannot move further, thus producing a limiting optical state or optical rail. Because there is a distribution of electrophoretic particle sizes and charges in such a medium, some particles hit the rails before others, creating a “soft rails” phenomenon, whereby the impulse precision required is reduced when the final optical state of a transition approaches the extreme black and white states, whereas the optical precision required increases dramatically in transitions ending near the middle of the optical range of the pixel. Various types of drive schemes for electro-optic displays are known which take advantage of optical rails. For example, FIGS. 9 and 10 of the aforementioned 2003/0137521 (reproduced below), and the related description at Paragraphs [0177] to [0180], describe a “slide show” drive scheme in which the entire display is driven to both optical rails before any new image is written. Such a slide show drive scheme produces accurate grayscale levels, but the flashing of the display as it is driven to the optical rails is distracting to the viewer. It has also been suggested (see the aforementioned U.S. Pat. No. 6,531,997) that a similar drive scheme be employed in which only the pixels, whose optical states need to be changed in the new image, be driven to the optical rails. However, this type of “limited slide show” drive scheme is, if anything, even more distracting to the viewer, since the solid flashing of a normal slide show drive scheme is replaced by image dependent flashing, in which features of the old image and the new image flash in reverse color on the screen before the new image is written. Obviously, a pure general grayscale image flow drive scheme cannot rely upon using the optical rails to prevent errors in gray levels since in such a drive scheme any given pixel can undergo an infinitely large number of changes in gray level without ever touching either optical rail. In one aspect, this invention seeks to provide methods for achieving control of gray levels in electro-optic displays which achieve stability of gray levels similar to those achieved by slide show drive schemes but which do not suffer from the distracting flashing of slide show drive schemes. Preferred methods of the present invention can give the viewer a visual experience similar to that provided by a pure general grayscale image flow drive scheme. In another aspect, this invention seeks to provide methods for achieving fine control of gray levels in displays driven by pulse width modulation. When driving an active matrix display having a bistable electro-optic medium to write gray scale images thereon, it is desirable to be able to apply a precise amount of impulse to each pixel, so as to achieve accurate control of the gray scale displayed. The driving method used may rely modulation of the voltage applied to each pixel and/or modulation of the “width” (duration) for which the voltage is applied. Since voltage modulated drivers and their associated power supplies are relatively costly, pulse width modulation is commercially attractive. However, during the scanning of an active matrix display using such pulse width modulation, conventional driver circuitry only allows one to apply a single voltage to any given pixel during any one scan of the matrix. Consequently, pulse width modulation driving of active matrix displays is effected by scanning the matrix multiple times, with the drive voltage being applied during none, some or all of the scans, depending upon the change desired in the gray level of the specific pixel. Each scan may be regarded as a frame of the drive waveform, with the complete addressing pulse being a superframe formed by a plurality of successive frames. It should be noted that, although the drive voltage is only applied to any specific pixel electrode for one line address time during each scan, the drive voltage persists on the pixel electrodes during the time between successive selections of the same line, only slowly decaying, so that the pixel is driven between successive selections of the same line. As already mentioned, each row of the matrix needs to be individually selected during each frame so that for high resolution displays (for example, 800×600 pixel displays) in practice the frame rate cannot exceed about 50 to 100 Hz; thus each frame typically lasts 10 to 20 ms. Frames of this length lead to difficulties in fine control of gray scale with many fast switching electro-optic medium. For example, some encapsulated electrophoretic media substantially complete a switch between their extreme optical states (a transition of about 30 L* units) within about 100 ms, and with such a medium a 20 ms frame corresponds to a gray scale shift of about 6 L* units. Such a shift is too large for accurate control of gray scale; the human eye is sensitive to differences in gray levels of about 1 L* unit, and controlling the impulse only in graduations equivalent to about 6 L* units is likely to give rise to visible artifacts, such as “ghosting” due to prior state dependence of the electro-optic medium, and pulses needed to ensure that the waveform used is DC balanced (see the applications mentioned in the “Cross Reference to Related Applications” section above). More specifically, ghosting may be experienced because, as discussed in some of the aforementioned patents and applications, the variation of gray level with applied impulse is not linear, and the total impulse needed for any specific change in gray level may vary with the time at which the impulse is applied and the intervening gray levels. For example, in a simple 4 gray level (2 bit) display having gray levels 0 (black), 1 (dark gray), 2 (light gray) and 3 (white), driven by a simple pulse width modulation drive scheme, these non-linearities may result in the actual gray level achieved after a notional 0-2 transition being different from the gray level achieved after a notional 1-2 transition, with the production of highly undesirable visual artifacts. This invention provides methods for achieving fine control of gray levels in displays driven by pulse width modulation, thus avoiding the aforementioned problems. SUMMARY OF INVENTION Accordingly, in one aspect, this invention provides a method for driving an electro-optic display having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states. The method comprises: displaying a first image on the display; and rewriting the display to display a second image thereon, wherein, during the rewriting of the display any pixel which has undergone a number of transitions exceeding a predetermined value, the predetermined value being at least one, without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image. This method may hereinafter for convenience be referred to as the “limited transitions method” of the present invention. In one form of this limited transitions method, the rewriting of the display is effected such that, once a pixel has been driven from one extreme optical state towards the opposed extreme optical state by a pulse of one polarity, the pixel does not receive a pulse of the opposed polarity until it has reached the opposed extreme optical state. Also, in the limited transitions methods, the predetermined value (predetermined number of transitions) is not greater than N/2, where N is the total number of gray levels capable of being displayed by a pixel. The limited transitions method may be effected using a tri-level driver, i.e., the rewriting of the display may be effected by applying to the or each pixel any one or more of voltages −V, 0 and +V. The limited transitions method may also be DC-balanced, i.e., the rewriting of the display may be effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded. In the limited transitions method of the present invention, the rewriting of the display may be effected such that the impulse applied to a pixel during a transition depends only upon the initial and final gray levels of that transition. Alternatively, the method may be adapted to take account of other states of the display, as described in more detail below. In one preferred form of the limited transitions method, for at least one transition undergone by the at least one pixel from a gray level R2 to a gray level R1, there is applied to the pixel a sequence of impulses of the form: −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) where “IP(Rx)” represents the relevant value from an impulse potential matrix having one value for each gray level, and TM(R1,R2) represents the relevant value from a transition matrix having one value for each R1/R2 combination. (For convenience, impulse sequences of this type may hereinafter be abbreviated as “−x/ΔIP/x” sequences.) Such −x/ΔIP/x sequences may be used for all transitions in which the initial and final gray levels are different. Also, in such −x/ΔIP/x sequences, the final “x” section may occupy more than one half of the maximum update time. The TM(R1,R2) or x values may be chosen such that the sign of each value is dependent only upon R1; in particular, these values may be chosen to be positive for one or more light gray levels and negative for one or more dark gray levels so that gray levels other than the two extreme optical states are approached from the direction of the nearer extreme optical state. The aforementioned −x/ΔIP/x sequences may contain additional pulses. In particular, such sequences may comprise an additional pair of pulses of the form [+y][−y], where y is an impulse value, which may be either negative or positive, the [+y] and [−y] pulses being inserted into the −x/ΔIP/x sequence. The sequence may further comprise a second additional pair of pulses of the form [+z][−z], where z is an impulse value different from y and may be either negative or positive, the [+z] and [−z] pulses being inserted into the −x/ΔIP/x sequence. The −x/ΔIP/x sequences may further comprise a period when no voltage is applied to the pixel. This “no voltage” period may occur between two elements of the −x/ΔIP/x sequence, or within a single element thereof. The −x/ΔIP/x sequences may include two or more “no voltage” periods. When using the aforementioned −x/ΔIP/x sequences, the display may comprise a plurality of pixels divided into a plurality of groups, and the transition may be effected by (a) selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period; (b) repeating the scanning of the groups of pixels during a second frame period; and (c) interrupting the scanning of the groups of pixels during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. In the limited transitions method, the rewriting of the display may be effected such that a transition to a given gray level is always effected by a final pulse of the same polarity. In particular, gray levels other than the two extreme optical states may be approached from the direction of the nearer extreme optical state. This invention also provides a method for driving an electro-optic display having a plurality of pixels divided into a plurality of groups. This method comprises: (a) selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period; (b) repeating the scanning of the groups of pixels during a second frame period; and (c) interrupting the scanning of the groups of pixels during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. This method may hereinafter for convenience be referred to as the “interrupted scanning” method of the present invention. In such an interrupted scanning method, typically the first and second frame periods are equal in length. The length of the pause period may be a sub-multiple of the length of one of the first and second frame periods. The interrupted scanning method may include multiple pause periods; thus the method may comprise scanning the groups of pixels during at least first, second and third frame periods, and interrupting the scanning of the groups of pixels during at least first and second pause periods between successive frame periods. The first, second and third frame periods may be substantially equal in length, and the total length of the pause periods be equal to one frame period or one frame period minus one pause period. Typically, in the interrupted scanning method, the pixels are arranged in a matrix having a plurality of rows and a plurality of columns with each pixel defined by the intersection of a given row and a given column, and each group of pixels comprises one row or one column of the matrix. The interrupted scanning method is preferably DC balanced, i.e., the scanning of the display is preferably effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded. In another aspect, this invention provides a method for driving an electro-optic display having a plurality of pixels, the pixels being driven with a pulse width modulated waveform capable of applying a plurality of differing impulses to each pixel. This method comprises: (a) storing data indicating whether application of a given impulse to a pixel will produce a gray level higher or lower than a desired gray level; (b) detecting when two adjacent pixels are both required to be in the same gray level; and (c) adjusting the impulses applied to the two pixels so that one pixel is below the desired gray level, while the other pixel is above the desired gray level. This method may hereinafter for convenience be referred to as the “balanced gray level” method of the present invention. In this method, the pixels may be divided into two groups such that each pixel has at least one neighbor of the opposite group, and different drive schemes be used for the two groups. Each the methods of the present invention as described above may be carried out with any of the aforementioned types of electro-optic media. Thus, the methods of the present invention may be used with electro-optic displays comprising an electrochromic or rotating bichromal member electro-optic medium, an encapsulated electrophoretic medium, or a microcell electrophoretic medium. Other types of electro-optic media may also be employed. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic representation of an apparatus of the present invention, a display which is being driven by the apparatus, and associated apparatus, and is designed to show the overall architecture of the system. FIG. 2 is a schematic block diagram of the controller unit shown in FIG. 1 and illustrates the output signals generated by this unit. FIG. 3 is a schematic block diagram showing the manner in which the controller unit shown in FIGS. 1 and 2 generates certain output signals shown in FIG. 2. FIGS. 4 and 5 illustrate two different sets of reference voltages which can be used in the display shown in FIG. 1. FIG. 6 is a schematic representation of tradeoffs between pulse width modulation and voltage modulation approaches in a look-up table method of the present invention. FIG. 7 is a block diagram of a custom driver useful in a look-up table method of the present invention. FIG. 8 is a flow chart illustrating a program which may be run by the controller unit shown in FIGS. 1 and 2. FIGS. 9 and 10 illustrate two drive schemes of the present invention. FIGS. 11A and 11B illustrate two parts of a further drive scheme of the present invention. FIG. 12 illustrates the preferred −x/ΔIP/x sequence for use in the methods of the present invention. FIG. 13 illustrates schematically how the waveform shown in FIG. 12 may be modified to include an additional pair of drive pulses. FIG. 14 illustrates one waveform produced by modifying the waveform of FIG. 12 in the manner illustrated in FIG. 13. FIG. 15 illustrates a second waveform produced by modifying the waveform of FIG. 12 in the manner illustrated in FIG. 13. FIG. 16 illustrates schematically how the waveform shown in FIG. 15 may be further modified to include an additional pair of drive pulses. FIG. 17 illustrates one waveform produced by modifying the waveform of FIG. 15 in the manner illustrated in FIG. 16. FIGS. 18-20 illustrate three modifications of the waveform shown in FIG. 12 to incorporate a period of zero voltage. FIGS. 21A-21E show five non contiguous waveforms which can be used in the methods of the present invention. FIG. 22 illustrates a problem in addressing an electro-optic display using various numbers of frames of a monopolar voltage. FIG. 23 illustrates one approach to solving the problem shown in FIG. 22 using a non-contiguous variant of a method of the present invention. FIG. 24 illustrates a second approach to solving the problem shown in FIG. 13 using a non-contiguous variant of a method of the present invention. FIG. 25 illustrates a waveform which may be used in a non-contiguous variant of a method of the present invention. FIG. 26 illustrates a base waveform which can be modified to produce the waveform shown in FIG. 25. FIG. 27 illustrates a problem in addressing an electro-optic display using various numbers of frames of a monopolar voltage while maintaining DC balance. FIG. 28 illustrates one approach to solving the problem shown in FIG. 18 using a non-contiguous addressing method. FIG. 29 illustrates a second approach to solving the problem shown in FIG. 18 using the non-contiguous addressing method. FIG. 30 illustrates the gray levels obtained in a nominally four gray level electro-optic display without using a non-contiguous addressing method, as described in the Example below. FIG. 31 illustrates the gray levels obtained from the same display as in FIG. 30 using various non-contiguous addressing sequences. FIG. 32 illustrates the gray levels obtained from the same display as in FIG. 30 using a modified non-contiguous drive scheme. FIG. 33 illustrates a simple DC balanced waveform which may be used to drive an electro-optic display. FIGS. 34 and 35 illustrate two modifications of the waveform shown in FIG. 33 to incorporate a period of zero voltage. FIG. 36 illustrates schematically how the waveform shown in FIG. 33 may be modified to include an additional pair of drive pulses. FIG. 37 illustrates one waveform produced by modifying the waveform of FIG. 33 in the manner illustrated in FIG. 36. FIG. 38 illustrates a second waveform produced by modifying the waveform of FIG. 33 in the manner illustrated in FIG. 36. FIG. 39 illustrates schematically how the waveform shown in FIG. 38 may be further modified to include a third pair of drive pulses. FIG. 40 illustrates one waveform produced by modifying the waveform of FIG. 38 in the manner illustrated in FIG. 39. FIG. 41 is a graph illustrating the reduced dwell time dependency which can be achieved by a compensation voltage method. FIG. 42 is a graph illustrating the effect of dwell time dependence in an electro-optic display. DETAILED DESCRIPTION From the foregoing, it will be apparent that the present invention provides several different improvements in methods for driving electro-optic displays. In the description below, the various different improvements provided by the present invention will normally be described separately, although it will be understood by those skilled in the imaging art that in practice a single display may make use of more than one of these major aspects; for example, a display which uses the limited transitions method of the present invention may also make use of the interrupted scanning method. Furthermore, since the improvements provided by the present invention can be applied to a wide variety of methods for driving electro-optic displays described in the applications mentioned in Paragraphs [0001] to [0004] hereof, including such features as temperature compensation and the like, it is deemed desirable, before setting out the details of the present improved methods, to given a general introduction describing these prior art methods. General Introduction As already mentioned, the methods of the present invention relate to driving electro-optic displays, typically having a plurality of pixels, each of which is capable of displaying at least three gray levels. The present methods may of course be applied to electro-optic displays having a greater number of gray levels, for example 4, 8, 16 or more. Also as already mentioned, driving bistable electro-optic displays requires very different methods from those normally used to drive liquid crystal displays (“LCD's”). In a conventional (non-cholesteric) LCD, applying a specific voltage to a pixel for a sufficient period will cause the pixel to attain a specific gray level. Furthermore, the liquid material is only sensitive to the magnitude of the electric field, not its polarity. In contrast, bistable electro-optic displays act as impulse transducers, so there is no one-to-one mapping between applied voltage and gray state attained; the impulse (and thus the voltage) which must be applied to a pixel to achieve a given gray state varies with the “initial” gray state of the relevant pixel. Furthermore, since bistable electro-optic displays need to be driven in both directions (white to black, and black to white) it is necessary to specify both the polarity and the magnitude of the impulse needed. At this point, it is considered desirable to define certain terms which are used herein in accordance with their conventional meaning in the display art. Most of the discussion below will concentrate upon one or more pixels of a display undergoing a single gray scale transition (i.e., a change from one gray level to another) from an “initial” state to a “final” state. Obviously, the initial state and the final state are so designated only with regard to the particular single transition being considered and in most cases the pixel with have undergone transitions prior to the “initial” state and will undergo further transitions after the “final” state. As explained below, some methods of the invention take account not only of the initial and final states of the pixel but also of “prior” states, in which the pixel existed prior to achieving the initial state. Where it is necessary to distinguish between multiple prior states, the term “first prior state” will be used to refer to the state in which the relevant pixel existed prior to the initial state, the term “second prior state” will be used to refer to the state in which the relevant pixel existed prior to the first prior state, and so on. The term “non-zero transition” is used to refer to a transition which effects a change of at least one unit in gray scale; the term “zero transition” may be used to refer to a “transition” which effects no overall change in gray scale of the selected pixel (although the gray level of the pixel may vary during the transition, the final gray level of the pixel after the transition is the same as the initial gray level thereof prior to the transition; also, of course, other pixels of the display may be undergoing non-zero transitions at the same time). As discussed in more detail below, prior states which may be taken into account in the methods of the present invention are of two types, namely “gray level” prior states (i.e., states determined a specific number of non-zero transitions prior to the transition being considered) and “temporal” prior states (i.e., states determined a specific time prior to the transition being considered). As will readily be apparent to those skilled in image processing, a method of the present invention may take account of only of the initial state of each pixel and the final state, and such a method may make use of a look-up table, which will be two-dimensional. However, as already mentioned, some electro-optic media display a memory effect and with such media it is desirable, when generating the output signal representative of the pulse or series of pulses to be applied to a pixel to effect a transition, to take into account not only the initial state of each pixel but also at least one prior state of the same pixel, in which case the look-up table will be three-dimensional. In some cases, it may be desirable to take into account more than one prior state of each pixel (the plurality of prior states thus taken into account may be any combination of gray level and temporal prior states), thus resulting in a look-up table having four (if only two prior states are taken into account) or more dimensions. From a formal mathematical point of view, the present methods may be regarded as using an algorithm that, given information about the initial, final and (optionally) prior states of an electro-optic pixel, as well as (optionally—see more detailed discussion below) information about the physical state of the display (e. g., temperature and total operating time), will produce a function V(t) which can be applied to the pixel to effect a transition to the desired final state. From this formal point of view, a device controller used to carry out the present methods may be regarded as essentially a physical embodiment of this algorithm, the controller serving as an interface between a device wishing to display information and an electro-optic display. Ignoring the physical state information for the moment, the algorithm is, in accordance with preferred methods of the present invention, encoded in the form of a look-up table or transition matrix. This matrix will have one dimension each for the desired final state, and for each of the other states (initial and any prior states) are used in the calculation. The elements of the matrix will contain a function V(t) that is to be applied to the electro-optic medium. The elements of the look-up table or transition matrix may have a variety of forms. In some cases, each element may comprise a single number. For example, an electro-optic display may use a high precision voltage modulated driver circuit capable of outputting numerous different voltages both above and below a reference voltage, and simply apply the required voltage to a pixel for a standard, predetermined period. In such a case, each entry in the look-up table could simply have the form of a signed integer specifying which voltage is to be applied to a given pixel. In other cases, each element may comprise a series of numbers relating to different portions of a waveform. For example, there are described below embodiments of the invention which use single- or double-prepulse waveforms, and specifying such a waveform necessarily requires several numbers relating to different portions of the waveform. Also described below is an embodiment of the invention which in effect applies pulse length modulation by applying a predetermined voltage to a pixel during selected ones of a plurality of sub-scan periods (frames) during a complete scan (superframe). In such an embodiment, the elements of the transition matrix may have the form of a series of bits specifying whether or not the predetermined voltage is to be applied during each sub-scan period (frame) of the relevant transition. Finally, as discussed in more detail below, in some cases, such as a temperature-compensated display, it may be convenient for the elements of the look-up table to be in the form of functions (or, in practice, more accurately coefficients of various terms in such functions). It will be apparent that the look-up tables used in some embodiments of the invention may become very large. To take an extreme example, consider a process of the invention for a 256 (28) gray level display using an algorithm that takes account of initial, final and two prior states. The necessary four-dimensional look-up table has 232 entries. If each entry requires (say) 64 bits (8 bytes), the total size of the look-up table would be approximately 32 Gbyte. While storing this amount of data poses no problems on a desktop computer, it may present problems in a portable device. However, in practice the size of such large look-up tables can be substantially reduced. In many instances, it has been found that there are only a small number of types of waveforms needed for a large number of different transitions, with, for example, the length of individual pulses of a general waveform being varied between different transitions. Consequently, the length of individual entries in the look-up table can be reduced by making each entry comprises (a) a pointer to an entry in a second table specifying one of a small number of types of waveform to be used; and (b) a small number of parameters specifying how this general waveform should be varied for the relevant transition. The values for the entries in the look-up table may be determined in advance through an empirical optimization process. Essentially, one sets a pixel to the relevant initial state, applies an impulse estimated to approximately equal that needed to achieve the desired final state and measures the final state of the pixel to determine the deviation, if any, between the actual and desired final state. The process is then repeated with a modified impulse until the deviation is less than a predetermined value, which may be determined by the capability of the instrument used to measure the final state. In the case of methods which take into account one or more prior states of the pixel, in addition to the initial state, it will generally be convenient to first determine the impulse needed for a particular transition when the state of the pixel is constant in the initial state and all preceding states used in determining the impulse, and then to “fine tune” this impulse to allow for differing previous states. The methods of the present invention desirably provide for modification of the impulse to allow for variation in temperature and/or total operating time of the display; compensation for operating time may be required because some electro-optic media “age” and their behavior changes after extended operation. Such modification may be done in one of two ways. Firstly, the look-up table may be expanded by an additional dimension for each variable that is to be taken into account in calculating the output signal. Obviously, when dealing with continuous variables such as temperature and operating time, it is necessary to quantize the continuous variable in order to maintain the look-up table at a practicable finite size. In order to find the waveform to be applied to the pixel, the calculation means may simply choose the look-up table entry for the table closest to the measured temperature. Alternatively, to provide more accurate temperature compensation, the calculation means may look up the two adjacent look-up table entries on either side of the measured continuous variable, and apply an appropriate interpolation algorithm to calculate the required entry at the measured intermediate value of the variable. For example, assume that the matrix includes entries for temperature in increments of 10° C. If the actual temperature of the display is 25° C., the calculation would look up the entries for 20° and 30° C., and use a value intermediate the two. Note that since the variation of characteristics of electro-optic media with temperature is often not linear, the set of temperatures for which the look-up table stores entries may not be distributed linearly; for example, the variation of many electro-optic media with temperature is most rapid at high temperatures, so that at low temperatures intervals of 20° C. between look-up tables might suffice, whereas at high temperatures intervals of 5° C. might be desirable. An alternative method for temperature/operating time compensation is to use look-up table entries in the form of functions of the physical variable(s), or perhaps more accurately coefficients of standard terms in such functions. For simplicity consider the case of a display which uses a time modulation drive scheme in which each transition is handled by applying a constant voltage (of either polarity) to each pixel for a variable length of time, so that, absent any correction for environmental variables, each entry in the look-up table could consist only of a single signed number representing the duration of time for which the constant voltage is to be applied, and its polarity. If it is desired to correct such a display for variations in temperature such that the time T. for which the constant voltage needs to be applied for a specific transition at a temperature t is given by: Tt=T0+AΔt +B(Δt)2 where T0 is the time required at some standard temperature, typically the mid-point of the intended operating temperature range of the display, and Δt is the difference between t and the temperature at which T0 is measured; the entries in the look-up table can consist of the values of T0, A and B for the specific transition to which a given entry relates, and the calculation means can use these coefficients to calculate Tt at the measured temperature. To put it more generally, the calculation means finds the appropriate look-up table entry for the relevant initial and final states, then uses the function defined by that entry to calculate the proper output signal having regard to the other variables to be taken into account. The relevant temperature to be used for temperature compensation calculations is that of the electro-optic material at the relevant pixel, and this temperature may differ significantly from ambient temperature, especially in the case of displays intended for outdoor use where, for example, sunlight acting through a protective front sheet may cause the temperature of the electro-optic layer to be substantially higher than ambient. Indeed, in the case of large billboard-type outdoor signs, the temperature may vary between different pixels of the same display if, for example, part of the display falls within the shadow of an adjacent building, while the reminder is in full sunlight. Accordingly, it may be desirable to embed one or more thermocouples or other temperature sensors within or adjacent to the electro-optic layer to determine the actual temperature of this layer. In the case of large displays, it may also be desirable to provide for interpolation between temperatures sensed by a plurality of temperature sensors to estimate the temperature of each particular pixel. Finally, in the case of large displays formed from a plurality of modules which can replaced individually, the method and controller of the invention may provide for different operating times for pixels in different modules. The methods of the present invention may also allow for the residence time (i.e., the period since the pixel last underwent a non-zero transition) of the specific pixel being driven. It has been found that, at least in some cases, the impulse necessary for a given transition various with the residence time of a pixel in its optical state, this phenomenon, which does not appear to have previously been discussed in the literature, hereinafter being referred to as “dwell time dependence” or “DTD”, although the term “dwell time sensitivity” was used in the aforementioned Application Ser. No. 60/320,070. Thus, it may be desirable or even in some cases in practice necessary to vary the impulse applied for a given transition as a function of the residence time of the pixel in its initial optical state. In one approach to allowing for DTD, the look-up table contains an additional dimension, which is indexed by a counter indicating the residence time of the pixel in its initial optical state. In addition, the controller may require an additional storage area that contains a counter for every pixel in the display, and a display clock, which increments by one the counter value stored in each pixel at a set interval. The length of this interval must be an integral multiple of the frame time of the display, and therefore must be no less than one frame time. (The frame time of the display may not be constant, but instead may vary from scan to scan, by adjusting either the line time or the delay period at the end of the frame. In this case, the relationship between the frame counter and the elapsed time may be calculated by summing the frame times for the individual frames comprising the update.) The size of this counter and the clock frequency will be determined by the length of time over which the applied impulse will be varied, and the necessary time resolution. For example, storing a 4-bit counter for each pixel would allow the impulse to vary at 0.25 second intervals over a 4-second period (4 seconds*4 counts/sec=16 counts=4 bits). The counter may optionally be reset upon the occurrence of certain events, such as the transition of the pixel to a new state. Upon reaching its maximum value, the counter may be configured to either “roll over” to a count of zero, or to maintain its maximum value until it is reset. The methods of the present invention may take account of not only the initial state of the relevant pixel and one or more gray level prior states of the same pixel, but also one or more temporal prior states of the pixel, i.e., data representing the state of the relevant pixel at defined points in time prior to the transition being considered. The output signal from the method is determined dependent upon the gray level and temporal prior states, and the initial state of the pixel. Allowing for both the gray state levels in which a given pixel existed prior to the initial state and the length of time for which the pixel remained in those gray levels reduces “image drift” (i.e., inaccuracy in gray levels). It is believed (although the invention is in no way limited by this belief) that such image drift is due to polarization within the electro-optic medium. Table 1 below illustrates a relatively simple application of a prior temporal/gray level state method to a two-bit (four gray level) gray scale display in which the various gray levels of denoted 0 (black), 1 (dark gray), 2 (light gray) and 3 (white). (Obviously, the method can be applied to applied to displays having large numbers of gray levels, for example a four-bit, 16 gray level, display having gray levels denoted from 0 (black) to 15 (white).) The middle line of Table 1 shows successive gray levels of a single pixel of the display; Table 1 assumes that the display is being updated continuously, so that the interval between adjacent columns of the display is one superframe (i.e., the interval necessary for a complete updating of the display). Obviously, if the present invention is applied to a display of a type (for example, a weather radar display) in which each updating if followed by a rest interval during which no rewriting of the display is effected, the interval between columns of Table 1 would be to be taken as one superframe plus the associated rest interval. TABLE 1 S10 S9 S8 S7 S6 S5 S4 S3 S2 S1 2 0 0 0 3 3 1 1 1 2 R5 R4 R4 R4 R3 R3 R2 R2 R2 R1 The top line of Table 1 shows the various temporal states Sx of the display, while the bottom of the table shows the corresponding gray level states Rx, the difference being that the temporal states change at intervals of one superframe, whereas the gray level states change only when there is a change in gray level (non-zero transition) of the relevant pixel. The right hand column of Table 1 represents the desired final state of the display after the transition being considered, while the penultimate column represents the initial state prior to this transition. Table 1 assumes a non-zero transition (i.e., that the final gray level is different from the initial gray level), since, at least in some cases, a zero transition in any one pixel of a bistable electro-optic display may be effected simply by not applying any voltage to the pixel during the relevant superframe. Thus, S1=R1=the desired final state of the pixel; S2=R2=the initial state of the pixel; S3=the first temporal prior state of the pixel; S4=the second temporal prior state of the pixel; and similarly for S5 to S10, while: R3=the first gray level prior state of the pixel; R4=the second gray level prior state of the pixel; and R5=the third gray level prior state of the pixel. The basic look-up table method described in the aforementioned 2003/0137521 uses a look-up table indexed by (i.e., having dimensions corresponding to) R1 and R2, and optionally any one or more successive ones of R3, R4 and R5. In contrast, the prior temporal/gray level state method uses a look-up table indexed by at least R1 (=S1), R2 (=S2), R3 and S3. Optionally, the prior temporal/gray level state method may use a look-up table indexed by any one or more successive ones of R4, R5 etc., and any one or more successive ones of S4, S5 etc. It is not necessary that the prior temporal/gray level state method take account of an equal number of temporal and gray level prior states, nor is it necessary that the prior temporal/gray level state method take account of successive temporal prior states extending over the same time interval as the gray level prior states of which the method takes account. Indeed, since the variations in impulse due to changes in temporal prior states tend to be smaller than those due to changes in gray level prior states, it may, for example, in some cases be advantageous for the prior temporal/gray level state method to take account of (say) the first and second gray level prior states (R3 and R4 respectively) and only the first temporal prior state (S3), even though clearly the second gray level prior state R4 occurs at a time prior to the first temporal prior state S3. As compared with the basic look-up table method, the prior temporal/gray level state method allows better compensation for effects (such as polarization fields building up with the electro-optic medium) due to the electro-optic medium “dwelling” in particular gray states for extended periods. This better compensation can reduce the overall complexity of the display controller and/or reduce the magnitude of image artifacts such as prior state ghosting. The prior temporal/gray level state method may make use of any of the optional features of the basic look-up table method described above. Thus, the elements of the look-up table or transition matrix may have a variety of forms. In some cases, each element may comprise a single number. In other cases, each element may comprise a series of numbers relating to different portions of a waveform. In still other cases, such as a temperature-compensated display, it may be convenient for the elements of the look-up table to be in the form of functions (or, in practice, more accurately coefficients of various terms in such functions). Similarly, to prevent the look-up tables becoming too large, the length of individual entries in the look-up table may be reduced by making each entry (a) a pointer to an entry in a second table specifying one of a small number of types of waveform to be used; and (b) a small number of parameters specifying how this general waveform should be varied for the relevant transition. Furthermore, since the data comprising a look-up table can be treated as a general multi-dimensional data set, any standard functions, algorithms and encodings known to those skilled in the art of data storage and processing may be employed to reduce one or more of (a) the size of the storage required for the data set, (b) the computational effort required to extract the data, or (c) the time required to locate and extract a specific element from the set. These storage techniques include, for example, hash functions, loss-less and lossy compression, and representation of the data set as a combination of basis functions. The values for the entries in the look-up table used in the prior temporal/gray level state method may be determined in advance through an empirical optimization process essentially similar to that described above for the basic look-up table method, although of course modified to allow for consideration of the one or more temporal prior states considered. To take into account the required number of temporal and gray level prior states of the pixel, it will generally be convenient to first determine the impulse needed for a particular transition when the state of the pixel is constant in the initial state and all prior states used in determining the impulse, and then to “fine tune” this impulse to allow for differing temporal and gray level prior states. The prior temporal/gray level state method desirably provides for modification of the impulse to allow for variation in temperature and/or total operating time of the display, in exactly the same way as described above for the basic look-up table method. Prior state, temperature, operation time and other external variables may be used to modify the structure of the transitions comprising the waveform, for example by inserting 0 V periods within a transition, while leaving the net impulse unchanged. Both the basic look-up table method and the prior temporal/gray level state method may of course be modified to take account of any other physical parameter which has a detectable effect upon the impulse needed to effect any one or more specific transitions of an electro-optic medium. For example, the method could be modified to incorporate corrections for ambient humidity if the electro-optic medium is found to be sensitive to humidity. For a bistable electro-optic medium, the look-up table may have the characteristic that, for any zero transition in which the initial and final states of the pixel are the same, the entry will be zero, or in other words, no voltage will be applied to the pixel. As a corollary, if no pixels on the display change during a given interval, then no impulses need be applied. This enables ultra-low power operation, as well as ensuring that the electro-optic medium is not overdriven while a static image is being displayed. In general, the look-up table may only retain information about non-null transitions. In other words, for two images, I and I+1, if a given pixel is in the same state in I and I+1, then state I+1 need not be stored in the prior state table, and no further information need be stored until that pixel undergoes a transition. However, as discussed below, at least in some cases it may still be advantageous to apply impulses to pixels undergoing zero transitions. The look-up table methods described above can be practiced with controllers having a variety of physical forms. and using any conventional data processing components. For example, the methods could be practiced using a general purpose digital computer in conjunction with appropriate equipment (for example, one or more digital analog converters, “DAC's”) to convert the digital outputs from the computer to appropriate voltages for application to pixels. Alternatively, the methods could be practiced using an application specific integrated circuit (ASIC). In particular, the controller could have the form of a video card which could be inserted into a personal computer to enable the images generated by the computer to be displayed on an electro-optic screen instead of or in addition to an existing screen, such as a LCD. Since the construction of the controller is well within the level of skill in the image processing art, it is unnecessary to describe its circuitry in detail herein. A preferred physical embodiment of the controller is a timing controller integrated circuit (IC). This IC accepts incoming image data and outputs control signals to a collection of data and select driver IC's, in order to produce the proper voltages at the pixels to produce the desired image. This IC may accept the image data through access to a memory buffer that contains the image data, or it may receive a signal intended to drive a traditional LCD panel, from which it can extract the image data. It may also receive any serial signal containing information that it requires to perform the necessary impulse calculations. Alternately, this timing controller can be implemented in software, or incorporated as a part of the CPU. The timing controller may also have the ability to measure any external parameters that influence the operation of the display, such as temperature. The controller can operate as follows. The look-up table(s) are stored in memory accessible to the controller. For each pixel in turn, all of the necessary initial, final and (optionally) prior and physical state information is supplied as inputs. The state information is then used to compute an index into the look-up table. In the case of quantized temperature or other correction, the return value from a look-up using this index will be one voltage, or an array of voltages versus time. The controller will repeat this process for the two bracketing temperatures in the look-up table, then interpolate between the values. For the algorithmic temperature correction, the return value of the look-up will be one or more parameters, which can then be inserted into an equation along with the temperature, to determine the proper form of the drive impulse, as already described. This procedure can be accomplished similarly for any other system variables that require real-time modification of the drive impulse. One or more of these system variables may be determined by, for example, the value of a programmable resistor, or a memory location in an EPROM, which is set on the display panel at the time of construction in order to optimize the performance of the display. An important feature of the display controller is that, unlike most displays, in most practical cases several complete scans of the display will be required in order to complete an image update. The series of scans required for one image update should be considered to be an uninterruptible unit. If the display controller and image source are operating asynchronously, then the controller must ensure that the data being used to calculate applied impulses remains constant across all scans. This can be accomplished in one of two ways. Firstly, the incoming image data could be stored in a separate buffer by the display controller (alternatively, if the display controller is accessing a display buffer through dual-ported memory, it could lock out access from the CPU). Secondly, on the first scan, the controller may store the calculated impulses in an impulse buffer. The second option has the advantage that the overhead for scanning the panel is only incurred once per transition, and the data for the remaining scans can be output directly from the buffer. Optionally, imaging updating may be conducted in an asynchronous manner. Although it will, in general, take several scans to effect a complete transition between two images, individual pixels can begin transitions, or reverse transitions that have already started, in mid-superframe. In order to accomplish this, the controller must keep track of what portion of the total transition have been accomplished for a given pixel. If a request is received to change the optical state of a pixel that is not currently in transition, then the counter for that pixel can be set to zero, and the pixel will begin transitioning on the next frame. If the pixel is actively transitioning when a new request is received, then the controller will apply an algorithm to determine how to reach the new state from the current mid-transition state. This may be effected, for example, by adding an extra dimension to the look-up table to indicate how many frames into the update a given pixel is before the request to transition to a new state is given. In this way, transitions can be specified not just between final gray states, but also between intermediate points in any transition to a new final gray state. In order to minimize the power necessary to operate a display, and to maximize the image stability of the electro-optic medium, the display controller may stop scanning the display and reduce the voltage applied to all pixels to, or close to, zero, when there are no pixels in the display that are undergoing transitions. Very advantageously, the display controller may turn off the power to its associated row and column drivers while the display is in such a “hold” state, thus minimizing power consumption. In this scheme, the drivers would be reactivated when the next pixel transition is requested. FIG. 1 of the accompanying drawings shows schematically an apparatus, useful for carrying out the driving methods of the present invention, in use, together with associated apparatus. The overall apparatus (generally designated 10) shown in FIG. 1 comprises an image source, shown as a personal computer 12 which outputs on a data line 14 data representing an image. The data line 14 can be of any conventional type and may be a single data line or a bus; for example, the data line 14 could comprise a universal serial bus (USB), serial, parallel, IEEE-1394 or other line. The data which are placed on the line 14 can be in the form of a conventional bit mapped image, for example a bit map (BMP), tagged image file format (TIF), graphics interchange format (GIF) or Joint Photographic Experts Group (JPEG) file. Alternatively, however, the data placed on the line 14 could be in the form of signals intended for driving a video device; for example, many computers provide a video output for driving an external monitor and signals on such outputs may be used in the present invention. It will be apparent to those skilled in imaging processing that the apparatus described below may have to perform substantial file format conversion and/or decoding to make use of the disparate types of input signals which can be used, but such conversion and/or decoding is well within the level of skill in the art, and accordingly, the apparatus will be described only from the point at which the image data used as its original inputs have been converted to a format in which they can be processed by the apparatus. The data line 14 extends to a controller unit 16, as described in detail below. This controller unit 16 generates one set of output signals on a data bus 18 and a second set of signals on a separate data bus 20. The data bus 18 is connected to two row (or gate) drivers 22, while the data bus 20 is connected to a plurality of column (or source) drivers 24. (The number of row drivers 22 and column drivers 24 is greatly reduced in FIG. 1 for ease of illustration.) The row and column drivers control the operation of a bistable electro-optic display 26. The apparatus shown in FIG. 1 is chosen to illustrate the various units used, and is most suitable for a developmental, “breadboard” unit. In actual commercial production, the controller 16 will typically be part of the same physical unit as the display 26, and the image source may also be part of this physical unit, as in conventional laptop computers equipped with LCD's, and in personal digital assistants. Also, the apparatus is illustrated in FIG. 1, and will be mainly described below, in conjunction with an active matrix display architecture which has a single common, transparent electrode (not shown in FIG. 1) on one side of the electro-optic layer, this common electrode extending across all the pixels of the display. Typically, this common electrode lies between the electro-optic layer and the observer and forms a viewing surface through which an observer views the display. On the opposed side of the electro-optic layer is disposed a matrix of pixel electrodes arranged in rows and columns such that each pixel electrode is uniquely defined by the intersection of a single row and a single column. Thus, the electric field experienced by each pixel of the electro-optic layer is controlled by varying the voltage applied to the associated pixel electrode relative to the voltage (normally designated “Vcom”) applied to the common front electrode. Each pixel electrode is associated with at least one transistor, typically a thin film transistor. The gates of the transistors in each row are connected via a single elongate row electrode to one of the row drivers 22. The source electrodes of the transistors in each column are connected via a single elongate column electrode to one of column drivers 24. The drain electrode of each transistor is connected directly to the pixel electrode. It will be appreciated that the assignment of the gates to rows and the source electrodes to columns is arbitrary, and could be reversed, as could the assignment of source and drain electrodes. However, the following description will assume the conventional assignments. During operation, the row drivers 22 apply voltages to the gates such that the transistors in one and only one row are conductive at any given time. Simultaneously, the column drivers 24 apply predetermined voltages to each of the column electrodes. Thus, the voltages applied to the column drivers are applied to only one row of the pixel electrodes, thus writing (or at least partially writing) one line of the desired image on the electro-optic medium. The row driver then shifts to make the transistors in the next row conductive, a different set of voltages are applied to the column electrodes, and the next line of the image is written. It is emphasized that the methods of the present invention are not confined to such active matrix displays. Once the correct waveforms for each pixel of the image have been determined in accordance with the methods of the present invention, any switching scheme may be used to apply the waveforms to the pixels. For example, the present methods can be used in a so-called “direct drive” scheme, in which each pixel is provided with a separate drive line. In principle, the present methods can also be used in a passive matrix drive scheme of the type used in some LCD's, but it should be noted that, since many bistable electro-optic media lack a threshold for switching (i.e., the media will change optical state if even a small electric field is applied for a prolonged period), such media are unsuitable for passive matrix driving. However, since it appears that the present methods will find their major application in active matrix displays, they will be described herein primarily with reference to such displays. The controller unit 16 (FIG. 1) has two main functions. Firstly, using the methods of the present invention, the controller calculates a two-dimensional matrix of impulses (or waveforms) which must be applied to the pixels of a display to change an initial image to a final image. Secondly, the controller 16 calculates, from this matrix of impulses, all the timing signals necessary to provide the desired impulses at the pixel electrodes to drive a bistable electro-optic display. As shown in FIG. 2, the controller unit 16 seen in FIG. 1 has two main sections, namely a frame buffer 16A, which buffers the data representing the final image which the controller 16B is to write to the display 26 (FIG. 1), and the controller proper, denoted 16B. The controller 16B reads data from the buffer 16A pixel by pixel and generates various signals on the data buses 18 and 20 as described below. The signals shown in FIG. 2 are as follows: D0:D5—a six-bit voltage value for a pixel (obviously, the number of bits in this signal may vary depending upon the specific row and column drivers used) POL—pixel polarity with respect to Vcom (see below) START—places a start bit into the column driver 24 to enable loading of pixel values HSYNC—horizontal synchronization signal, which latches the column driver PCLK—pixel clock, which shifts the start bit along the row driver VSYNC—vertical synchronization signal, which loads a start bit into the row driver OE—output enable signal, which latches the row driver. Of these signals, VSYNC and OE supplied to the row drivers 22 are essentially the same as the corresponding signals supplied to the row drivers in a conventional active matrix LCD, since the manner of scanning the rows in the apparatus shown in FIG. 1 is in principle identical to the manner of scanning an LCD, although of course the exact timing of these signals may vary depending upon the precise electro-optic medium used. Similarly, the START, HSYNC and PCLK signals supplied to the column drivers are essentially the same as the corresponding signals supplied to the column drivers in a conventional active matrix LCD, although their exact timing may vary depending upon the precise electro-optic medium used. Hence, it is considered that no further description of these output signals in necessary. FIG. 3 illustrates, in a highly schematic manner, the way in which the controller 16B shown in FIG. 2 generates the D0:D5 and POL signals. As described above, the controller 16B stores data representing the final image 120 (the image which it is desired to write to the display), the initial image 122 previously written to the display, and optionally one or more prior images 12 which were written to the display before the initial image. The embodiment of the invention shown in FIG. 3 stores two such prior images 123. (Obviously, the necessary data storage can be within the controller 16B or in an external data storage device.) The controller 16B uses the data for a specific pixel (illustrated as the first pixel in the first row, as shown by the shading in FIG. 3) in the initial, final and prior images 120. 122 and 123 as pointers into a look-up table 124, which provides the value of the impulse which must be applied to the specific pixel to change the state of that pixel to the desired gray level in the final image. The resultant output from the look-up table 124, and the output from a frame counter 126, are supplied to a voltage v. frame array 128, which generates the D0:D5 and POL signals. The controller 16B (FIG. 2) is designed for use with a TFT LCD driver that is equipped with pixel inversion circuitry, which ordinarily alternates the polarity of neighboring pixels with respect to the top plane. Alternate pixels will be designated as even and odd, and are connected to opposing sides of the voltage ladder. Furthermore, a driver input, labeled “polarity”, serves to switch the polarity of the even and odd pixels. The driver is provided with four or more gamma voltage levels, which can be set to determine the local slope of the voltage-level curve. A representative example of a commercial integrated circuit (IC) with these features is the Samsung KS0652 300/309 channel TFT-LCD source driver. As previously discussed, the display to be driven uses a common electrode on one side of the electro-optic medium, the voltage applied to this common electrode being referred to as the “top plane voltage” or “Vcom”. In one embodiment, illustrated in FIG. 4 of the accompanying drawings, the reference voltages of the driver are arranged so that the top plane voltage is placed at one half the maximum voltage (Vmax) which the driver can supply, i.e., Vcom=Vmax/2 and the gamma voltages are arranged to vary linearly above and below the top plane voltage. (FIGS. 4 and 5 are drawn assuming an odd number of gamma voltages so that, for example, in FIG. 4 the gamma voltage VGMA(n/2+1/2) is equal to Vcom. If an even number of gamma voltages are present, both VGMA(n/2) and VGMA(n/2+1) are set equal to Vcom. Similarly, in FIG. 5, if an even number of gamma voltages are present, both VGMA(n/2) and VGMA(n/2+1) are set equal to the ground voltage Vss.) The pulse length necessary to achieve all needed transitions is determined by dividing the largest impulse needed to create the new image by Vmax/2. This impulse can be converted into a number of frames by multiplying by the scan rate of the display. The necessary number of frames is then multiplied by two, to give an equal number of even and odd frames. These even and odd frames will correspond to whether the polarity bit is set high or low for the frame. For each pixel in each frame, the controller 16B must apply an algorithm which takes as its inputs (1) whether the pixel is even or odd; (2) whether the polarity bit is high or low for the frame being considered; (3) whether the desired impulse is positive or negative; and (4) the magnitude of the desired impulse. The algorithm then determines whether the pixel can be addressed with the desired polarity during that frame. If so, the proper drive voltage (impulse/pulse length) is applied to the pixel. If not, then the pixel is brought to the top plane voltage (Vmax/2) to place it in a hold state, in which no electric field is applied to the pixel during that frame. For example, consider two neighboring pixels in the display, an odd pixel 1 and an even pixel 2. Further, assume that when the polarity bit is high, the odd pixels will be able to access the positive drive voltage range (i.e. above the top plane voltage), and the even pixels will be able to access the negative voltages (i.e. below the top plane voltage ). If both pixels 1 and 2 need to be driven with a positive impulse, then the following sequence must occur: (a) during the positive polarity frames, pixel 1 is driven with a positive voltage, and pixel 2 is held at the top plane voltage; and (b) during the negative polarity frames, pixel 1 is held at the top plane voltage, while pixel 2 is driven with a positive voltage. Although typically frames with positive and negative polarity will be interleaved 1:1 (i.e., will alternate with each other), but this is not necessary; for example, all the odd frames could be grouped together, followed by all the even frames. This would result in alternate columns of the display being driven in two separate groups. The major advantage of this embodiment is that the common front electrode does not have to be switched during operation. The primary disadvantage is that the maximum drive voltage available to the electro-optic medium is only half of the maximum voltage of the driver, and that each line may only be driven 50% of the time. Thus. the refresh time of such a display is four times the switching time of the electro-optic medium under the same maximum drive voltage. In a second embodiment of this form of the invention, the gamma voltages of the driver are arranged as shown in FIG. 5, and the common electrode switches between V=0 and V=Vmax. Arranging the gamma voltages in this way allows both even and odd pixels to be driven simultaneously in a single direction, but requires that the common electrode be switched to access the opposite drive polarity. In addition, because this arrangement is symmetric about the top plane voltage, a particular input to the drivers will result in the same voltage being applied on either an odd or an even pixel. In this case, the inputs to the algorithm are the magnitude and sign of the desired impulse, and the polarity of the top plane. If the current common electrode setting corresponds to the sign of the desired impulse, then this value is output. If the desired impulse is in the opposite direction, then the pixel is set to the top plane voltage so that no electric field is applied to the pixel during that frame. As in the embodiment previously described, in this embodiment the necessary length of the drive pulse can be calculated by dividing the maximum impulse by the maximum drive voltage, and this value converted into frames by multiplying by the display refresh rate. Again, the number of frames must be doubled, to account for the fact that the display can only be driven in one direction with respect to the top plane at a time. The major advantage of this second embodiment is that the full voltage of the driver can be used, and all of the outputs can be driven at once. However, two frames are required for driving in opposed directions. Thus. the refresh time of such a display is twice the switching time of the electro-optic medium under the same maximum drive voltage. The major drawback is the need to switch the common electrode, which may result in unwanted voltage artifacts in the electro-optic medium, the transistors associated with the pixel electrodes, or both. In either embodiment, the gamma voltages are normally arranged on a linear ramp between the maximum voltages of the driver and the top plane voltage. Depending upon the design of the driver, it may be necessary to set one or more of the gamma voltages at the top plane value, in order to ensure that the driver can actually produce the top plane voltage on the output. Reference has already been made above to the need to adapt the method of the present invention to the limitations of conventional drivers designed for use with LCD's. More specifically, conventional column drivers for LCD's, and particularly super twisted nematic (STN) LCD's (which can usually handle higher voltages than other types of column drivers), are only capable of applying one of two voltages to a drive line at any given time, since this is all that a polarity-insensitive LC material requires. In contrast, to drive polarity-sensitive electro-optic displays, a minimum of three driver voltage levels are necessary. The three driver voltages required are V−, which drives a pixel negative with respect to the top plane voltage, V+, which drives a pixel positive with respect to the top plane voltage, and 0 V with respect to the top plane voltage, which will hold the pixel in the same display state. The methods of the present invention can, however, be practiced with this type of conventional LCD driver, provided that the controller is arranged to apply an appropriate sequence of voltages to the inputs of one or more column drivers, and their associated row drivers, in order to apply the necessary impulses to the pixels of an electro-optic display. There are two principal variants of this approach. In the first variant, all the impulses applied must have one of three values: +I, −I or 0, where: +I=−(−I)=Vapp*tpulse where Vapp is the applied voltage above the top plane voltage, and tpulse is the pulse length in seconds. This variant only allows the display to operate in a binary (black/white) mode. In the second variant, the applied impulses may vary from +I to −I, but must be integral multiples of Vapp/freq, where freq is the refresh frequency of the display. This variant takes advantage of the fact that, as already noted, conventional LCD drivers are designed to reverse polarity at frequent intervals to avoid certain undesirable effects which might otherwise be produced in the display. Consequently, such drivers are arranged to receive from the controller a polarity or control voltage, which can either be high or low. When a low control voltage is asserted, the output voltage on any given driver output line can adopt one of two out of the possible three voltages required, say V1 or V2, while when a high control voltage is asserted, the output voltage on any given line can adopt one of a different two of the possible three voltages required, say V2 or V3. Thus, while only two out of the three required voltages can be addressed at any specific time, all three voltages can be achieved at differing times. The three required voltages will usually satisfy the relationship: V2=(V3+V1)/2 and V1 may be at or near the logic ground. In this method, the display will be scanned 2*tpulse*freq times. For half these scans (i.e., for tpulse*freq scans), the driver will be set to output either V1 or V2, which will normally be equal to −V and Vcom, respectively. Thus, during these scans, the pixels are either driven negative, or held in the same display state. For the other half of the scans, the driver will be switched to output either V2 or V3, which will normally be at Vcom and +V respectively. In these scans, the pixels are driven positive or held in the same display state. Table 2 below illustrates how these options can be combined to produce a drive in either direction or a hold state; the correlation of positive driving with approach to a dark state and negative driving with approach to a light state is of course a function of the specific electro-optic medium used. TABLE 2 Drive sequence for achieving bi-directional drive plus hold with STN drivers Driver outputs Desired Drive V1 − V2 V2 − V3 positive (drive dark) V2 V3 negative (drive white) V1 V2 hold V2 V2 There are several different ways to arrange the two portions of the drive scheme (i.e., the two different types of scans or “frames”). For example, the two types of frames could alternate. If this is done at a high refresh rate, then the electro-optic medium will appear to be simultaneously lightening and darkening, when in fact it is being driven in opposed direction in alternate frames. Alternatively, all of the frames of one type could occur before any of the frames of the second type; this would result in a two-step drive appearance. Other arrangements are of course possible; for example two or more frames of one type followed by two or more of the opposed type. Additionally, if there are no pixels that need to be driven in one of the two directions, then the frames of that polarity can be dropped, reducing the drive time by 50%. While this first variant can only produce binary images, the second variant can render images with multiple gray scale levels. This is accomplished by combining the drive scheme described above with modulation of the pulse widths for different pixels. In this case, the display is again scanned 2*tpulse*freq times, but the driving voltage is only applied to any particular pixel during enough of these scans to ensure that the desired impulse for that particular pixel is achieved. For example, for each pixel, the total applied impulse could be recorded, and when the pixel reached its desired impulse, the pixel could be held at the top plane voltage for all subsequent scans. For pixels that need to be driven for less than the total scanning time, the driving portion of this time (i.e., the portion of the time during which an impulse is applied to change the display state of the pixel, as opposed to the holding portion during which the applied voltage simply maintains the display state of the pixel) may be distributed in a variety of ways within the total time. For example, all driving portions could be set to start at the beginning of the total time, or all driving portions could instead be timed to complete at the end of the total time. As in the first variant, if at any time in the second variant no further impulses of a particular polarity need to be applied to any pixel, then the scans applying pulses of that polarity can be eliminated. This may mean that the entire pulse is shortened, for example, if the maximum impulse to be applied in both the positive and negative directions is less than the maximum allowable impulse. To take a highly simplified case for purposes of illustration, consider the application of the gray scale scheme described above to a display having four gray levels, namely black (level 0), dark gray (level 1), light gray (level 2) and white (level 3). One possible drive scheme for such a display is summarized in Table 3 below. TABLE 3 Frame No. 1 2 3 4 5 6 Parity Odd Even Odd Even Odd Even Transition 0-3 + 0 + 0 + 0 0-2 + 0 + 0 0 0 0-1 + 0 0 0 0 0 0-0 0 0 0 0 0 0 3-0 0 − 0 − 0 − 2-0 0 − 0 − 0 0 1-0 0 − 0 0 0 0 For ease of illustration, this drive scheme is assumed to use only six frames, although in practice a greater number would typically be employed. These frames are alternately odd and even. White-going transitions (i.e., transitions in which the gray level is increased) are driven only on the odd frames, while black-going transitions (i.e., transitions in which the gray level is decreased) are driven only on the even frames. On any frame when a pixel is not being driven, it is held at the same voltage as the common front electrode, as indicated by “0” in Table 3. For the 0-3 (black-white) transition, a white-going impulse is applied (i.e., the pixel electrode is held at a voltage relative to the common front electrode which tends to increase the gray level of the pixel) in each of the odd frames, Frames 1, 3 and 5. For a 0-2 (black to light gray) transition, on the other hand, a white-going impulse is applied only in Frames 1 and 3, and no impulse is applied in Frame 5; this is of course arbitrary, and, for example, a white-going impulse could be applied in Frames 1 and 5 and no impulse applied in Frame 3. For a 0-1 (black to dark gray) transition, a white-going impulse is applied only in Frame 1, and no impulse is applied in Frames 3 and 5; again, this is arbitrary, and, for example, a white-going impulse could be applied in Frame 3 and no impulse applied in Frames 1 and 5. The black-going transitions are handled in a manner exactly similar to the corresponding white-going transitions except that the black-going impulses are applied only in the even frames of the drive scheme. It is believed that those skilled in driving electro-optic displays will readily be able to understand the manner in which the transitions not shown in Table 3 are handled from the foregoing description. The sets of impulses described above can either be stand-alone transitions between two images (as in general image flow), or they may be part of a sequence of impulses designed to accomplish an image transition (as in a slide-show waveform, as discussed in more detail below). Although emphasis has been laid above on driving methods which permit the use of conventional drivers designed for use with LCD's, the present methods can make use of custom drivers, and a driver which is intended to enable accurate control of gray states in an electro-optic display, while achieving rapid writing of the display will now be described with reference to FIGS. 6 and 7. As already discussed, to first order, many electro-optic media respond to a voltage impulse, which can be expressed as V times t (or more generally, by the integral of V with respect to t) where V is the voltage applied to a pixel and t is the time over which the voltage is applied. Thus, gray states can be obtained by modulating the length of the voltage pulse applied to the display, or by modulating the applied voltage, or by a combination of these two. In the case of pulse width modulation in an active matrix display, the attainable pulse width resolution is simply the inverse of the refresh rate of the display. In other words, for a display with a 100 Hz refresh rate, the pulse length can be subdivided into 10 ms intervals. This is because each pixel in the display is only addressed once per scan, when the select line for the pixels in that row are activated. For the rest of the time, the voltage on the pixel may be maintained by a storage capacitor, as described in the aforementioned WO 01/07961. As the response speed of the electro-optic medium becomes faster, the slope of the reflectivity versus time curve becomes steeper and steeper. Thus, to maintain the same gray scale resolution, the refresh rate of the display must increase accordingly. Increasing the refresh rate results in higher power consumption, and eventually becomes impractical as the transistors and drivers are expected to charge the pixel and line capacitance in a shorter and shorter time. On the other hand, in a voltage modulated display, the impulse resolution is simply determined by the number of voltage steps, and is independent of the speed of the electro-optic medium. The effective resolution can be increased by imposing a nonlinear spacing of the voltage steps, concentrating them where the voltage/reflectivity response of the electro-optic medium is steepest. FIG. 6 of the accompanying drawings is a schematic representation of the tradeoffs between the pulse width modulation (PWM) and voltage modulation (VM) approaches. The horizontal axis represents pulse length, while the vertical axis represents voltage. The reflectivity of the particle-based electrophoretic display as a function of these two parameters is represented as a contour plot, with the bands and spaces representing differences of 1 L* in the reflected luminance of the display. (It has been found empirically that a difference in luminance of 1 L* is just noticeable to an average subject in dual stimulus experiments.) The particular particle-based electrophoretic medium used in the experiments summarized in FIG. 6 had a response time of 200 ms at the maximum voltage (16 V) shown in the Figure. The effects of pulse width modulation alone can be determined by traversing the plot horizontally along the top, while the effects of voltage modulation alone are seen by examining the right vertical edge. From this plot, it is clear that, if a display using this particular medium were driven at a refresh rate of 100 Hz in a pulse width modulation (PWM) mode, it would not be possible to obtain a reflectivity within ±1 L* in the middle gray region, where the contours are steepest. In voltage modulation (VM) mode, achieving a reflectivity within ±1 L* would require 128 equally spaced voltage levels, while running at a frame rate as low as 5 Hz (assuming, of course, that the voltage holding capability of the pixel, provided by a capacitor, is high enough). In addition, these two approaches can be combined to achieve the same accuracy with fewer voltage levels. To further reduce the required number of voltage levels, they could be concentrated in the steep middle portion of the curves shown in FIG. 6 but made sparse in the outer regions. This could be accomplished with a small number of input gamma voltages. To further reduce the required number of voltage levels, they could be concentrated at advantageous values. For example, very small voltages are not useful for achieving transitions if application of such a small voltage over the allotted address time is not sufficient to make any of the desired gray state transitions. Choosing a distribution of voltages that excludes such small voltages allows the allowed voltages to be more advantageously placed. Since bistable electro-optic displays are sensitive to the polarity of the applied electric field, as noted above, it is not desirable to reverse the polarity of the drive voltage on successive frames (images), as is usually done with LCD's, and frame, pixel and line inversion are unnecessary, and indeed counterproductive. For example, LCD drivers with pixel inversion deliver voltages of alternating polarity in alternate frames. Thus, it is only possible to deliver an impulse of the proper polarity in one half of the frames. This is not a problem in an LCD, where the liquid crystal material in not sensitive to polarity, but in a bistable electro-optic display it doubles the time required to address the electro-optic medium. Similarly, because bistable electro-optic displays are impulse transducers and not voltage transducers, the displays integrate voltage errors over time, which can result in large deviations of the pixels of the display from their desired optical states. This makes it important to use drivers with high voltage accuracy, and a tolerance of ±3 mV or less is recommended. To enable a driver to address a monochrome XGA (1024×768) display panel at a 75 Hz refresh rate, a maximum pixel clock rate of 60 MHz is required; achieving this clock rate is within the state of the art. As already mentioned, one of the primary virtues of particle-based electrophoretic and other similar bistable electro-optic displays is their image stability, and the consequent opportunity to run the display at very low power consumption. To take maximum advantage of this opportunity, power to the driver should be disabled when the image is not changing. Accordingly, the driver should be designed to power down in a controlled manner, without creating any spurious voltages on the output lines. Because entering and leaving such a “sleep” mode will be a common occurrence, the power-down and power-up sequences should be as rapid as possible, and should have minimal effects on the lifetime of the driver. In addition, there should be an input pin that brings all of the driver output pins to Vcom, which will hold all of the pixels at their current optical state without powering down the driver. The present drivers are useful, inter alia, for driving medium to high resolution, high information content portable displays, for example a 7 inch (178 mm) diagonal XGA monochrome display. To minimize the number of integrated circuits required in such high resolution panels, it is desirable to use drivers with a high number (for example, 324) of outputs per package. It is also desirable that the driver have an option to run in one or more other modes with fewer of its outputs enabled. The preferred method for attaching the integrated circuits to the display panel is tape carrier package (TCP), so it is desirable to arrange the sizing and spacing of the driver outputs to facilitate use of this method. The present drivers will typically be used to drive small to medium size active matrix panels at around 10-30 V Accordingly, the drivers should be capable of driving capacitative loads of approximately 100 pF. A block diagram of a preferred driver (generally designated 200) useful in the methods of the invention is given in FIG. 7 of the accompanying drawings. This driver 200 comprises a shift register 202, a data register 204, a data latch 206, a digital to analogue converter (DAC) 208 and an output buffer 210. This driver differs from those typically used to drive LCD's in that it provides for a polarity bit associated with each pixel of the display, and for generating an output above or below the top plane voltage controlled by the relevant polarity bit. The signal descriptions for this preferred driver are given in the following Table 4: TABLE 4 Symbol Pin Name Description VDD Logic power supply 2.7-3.6 V AVDD Driver power supply 10-30 V VSS Ground 0 V Y1-Y324 Driver outputs, fed to the D/A converted 64 level column electrodes of the analog outputs display D0(0:5) Display data input, odd 6 bit gray scale data for dots odd dots, D0: 0 = least significant bit (LSB) D1(0:5) Display data input, even 6 bit gray scale data for dots even dots, D1: 0 = LSB D0POL Odd dot polarity control Determines which set of input gamma voltages current odd dot will reference. D0POL = 1: odd dot will reference VGAM6-11 D0POL = 0: odd dot will reference VGAM1-6 D1POL Even dot polarity control Determines which set of input gamma voltages current even dot will reference. D1POL = 1: odd dot will reference VGAM6-11 D1POL = 0: odd dot will reference VGAM1-6 SHL Shift direction control Controls shift direction input in 162 bit shift register SHL = H: DIO1 input, Y1->Y324 SHL = L: DIO1 output, Y324->Y1 DIO1 Start pulse input/output SHL = H: Used as the start pulse input pin SHL = L: Used as the start pulse output pin DIO2 Start pulse input/output SHL = H: Used as the for 256 lines start pulse output pin for 256 lines active SHL = L: Used as the start pulse input pin for 256 lines, tie low if not used DIO3 Start pulse input/output SHL = H: Used as the for 260 lines start pulse output pin for 260 lines active SHL = L: Used as the start pulse input pin for 260 lines, tie low if not used DIO4 Start pulse input/output SHL = H: Used as the for 300 lines start pulse output pin for 300 lines active SHL = L: Used as the start pulse input pin for 300 lines, tie low if not used DIO5 Start pulse input/output SHL = H: Used as the for 304 lines start pulse output pin for 304 lines active SHL = L: Used as the start pulse input pin for 304 lines, tie low if not used DIO6 Start pulse input/output SHL = H: Used as the for 320 lines start pulse output pin for 320 lines active SHL = L: Used as the start pulse input pin for 320 lines, tie low if not used DIO7 Start pulse input/output SHL = H: Used as the for 324 lines start pulse output pin for 324 lines active SHL = L: Used as the start pulse input pin for 324 lines, tie low if not used CLK1 Shift clock input Two 6 bit gray values and two polarity control values for two display dots are loaded at every rising edge CLK2 Latch input Latches the contents of the data register on a rising edge and transfers latched values to the D/A converter block. BL Blanking input (this does Sets all outputs to not actually blank the VGAM6 level BL = H: bistable display, but All outputs set to simply stops the driver VGAM6 BL = L: All writing to the display, outputs reflect D/A thus allowing the image values already written to remain) VGAM1-6 Lower gamma reference Determine grayscale voltages voltage outputs through resistive DAC system VGAM6-11 Upper gamma reference Determine grayscale voltages voltage outputs through resistive DAC system The driver 200 operates in the following manner. First, a start pulse is provided by setting (say) DIO1 high to reset the shift register 202 to a starting location. (As will readily be apparent to those skilled in display driver technology, the various DIOx inputs to the shift register are provided to enable the driver to be used with displays having varying numbers of columns, and only one of these inputs is used with any given display, the others being tied permanently low.) The shift register now operates in the conventional manner used in LCD's; at each pulse of CLK1, one and only one of the 162 outputs of the shift register 202 goes high, the others being held low, and the high output being shifted one place at each pulse of CLK1. As schematically indicated in FIG. 7, each of the 162 outputs of the shift register 202 is connected to two inputs of data register 204, one odd input and one even input. The display controller (cf. FIG. 2) provides two six-bit impulse values D0(0:5) and D1(0:5) and two single-bit polarity signals D0POL and D1POL on the inputs of the data register 204. At the rising edge of each clock pulse CLK1, two seven-bit numbers (D0POL+D0(0:5) and D1POL+D1(0:5)) are written into registers in data register 204 associated with the selected (high) output of shift register 202. Thus, after 162 clock pulses CLK1, 324 seven-bit numbers (corresponding to the impulse values for one complete line of the display for one frame) have been written into the 324 registers present in data register 204. At the rising edge of each clock pulse CLK2, these 324 seven-bit numbers are transferred from the data register 204 to the data latch 206. The numbers thus placed in the data latch 206 are read by the DAC 208 and, in conventional fashion, corresponding analogue values are placed on the outputs of the DAC 208 and fed, via the buffer 210 to the column electrodes of the display, where they are applied to pixel electrodes of one row selected in conventional fashion by a row driver (not shown). It should be noted, however, that the polarity of each column electrode with respect to Vcom is controlled by the polarity bit D0POL or D1POL written into the data latch 206 and thus these polarities do not alternate between adjacent column electrodes in the conventional manner used in LCD's. FIG. 8 is a flow chart illustrating a program which may be run by the controller unit shown in FIGS. 1 and 2. This program (generally designated 300) is intended for use with a look-up table method (described in more detail below) in which all pixels of a display are erased and then re-addressed each time an image is written or refreshed. The program begins with a “powering on” step 302 in which the controller is initialized, typically as a result of user input, for example a user pushing the power button of a personal digital assistant (PDA). The step 302 could also be triggered by, for example, the opening of the case of a PDA (this opening being detected either by a mechanical sensor or by a photodetector), by the removal of a stylus from its rest in a PDA, by detection of motion when a user lifts a PDA, or by a proximity detector which detects when a user's hand approaches a PDA. The next step 304 is a “reset” step in which all the pixels of the display are driven alternately to their black and white states. It has been found that, in at least some electro-optic media, such “flashing” of the pixels is necessary to ensure accurate gray states during the subsequent writing of an image on the display. It has also been found that typically at least five flashes (counting each successive black and white state as one flash) are required, and in some cases more. The greater the number of flashes, the more time and energy that this step consumes, and thus the longer the time that must elapse before the user can see a desired image upon the display. Accordingly, it is desirable that the number of flashes be kept as small as possible consistent with accurate rendering of gray states in the image subsequently written. At the conclusion the reset step 304, all the pixels of the display are in the same black or white state. The next step 306 is a writing or “sending out image” step in which the controller 16 sends out signals to the row and column drivers 22 and 24 respectively (FIGS. 1 and 2) in the manner already described, thus writing a desired image on the display. Since the display is bistable, once the image has been written, it does not need to be rewritten immediately, and thus after writing the image, the controller can cause the row and column drivers to cease writing to the display, typically by setting a blanking signal (such as setting signal BL in FIG. 7 high). The controller now enters a decision loop formed by steps 308, 310 and 312. In step 308, the controller 16 checks whether the computer 12 (FIG. 1) requires display of a new image. If so, the controller proceeds, in an erase step 314 to erase the image written to the display at step 306, thus essentially returning the display to the state reached at the end of reset step 304. From erase step 314, the controller returns to step 304, resets as previously described, and proceeds to write the new image. If at step 308 no new image needs to be written to the display, the controller proceeds to a step 310, at which it determines when the image has remained on the display for more than a predetermined period. As is well known to those skilled in display technology, images written on bistable media do not persist indefinitely, and the images gradually fade (i.e., lose contrast). Furthermore, in some types of electro-optic medium, especially electrophoretic media, there is often a trade-off between writing speed of the medium and bistability, in that media which are bistable for hours or days have substantially longer writing times than media which are only bistable for seconds or minutes. Accordingly, although it is not necessary to rewrite the electro-optic medium continuously, as in the case of LCD's, to provide an image with good contrast, it may be desirable to refresh the image at intervals of (say) a few minutes. Thus, at step 310 the controller determines whether the time which has elapsed since the image was written at step 306 exceeds some predetermined refresh interval, and if so the controller proceeds to erase step 314 and then to reset step 304, resets the display as previously described, and proceeds to rewrite the same image to the display. (The program shown in FIG. 8 may be modified to make use of both local and global rewriting. If so, step 310 may be modified to decide whether local or global rewriting is required. If, in this modified program, at step 310 the program determines that the predetermined time has not expired, no action is taken. If, however, the predetermined time has expired, step 310 does not immediately invoke erasure and rewriting of the image; instead step 310 simply sets a flag (in the normal computer sense of that term) indicating that the next image update should be effected globally rather than locally. The next time the program reaches step 306, the flag is checked; if the flag is set, the image is rewritten globally and then the flag is cleared, but if the flag is not set, only local rewriting of the image is effected.) If at step 310 it is determined that the refresh interval has not been exceeded, the controller proceeds to a step 312, where it determines whether it is time to shut down the display and/or the image source. In order to conserve energy in a portable apparatus, the controller will not allow a single image to be refreshed indefinitely, and terminates the program shown in FIG. 8 after a prolonged period of inactivity. Accordingly, at step 310 the controller determines whether a predetermined “shut-down” period (greater than the refresh interval mentioned above) has elapsed since a new image (rather than a refresh of a previous image) was written to the display, and if so the program terminates, as indicated at 314. Step 314 may include powering down the image source. Naturally, the user still has access to a slowly-fading image on the display after such program termination. If the shut-down period has not been exceeded, the controller proceeds from step 312 back to step 308. Some general considerations regarding waveforms to be used in the methods of the present invention will be discussed. Waveforms for bistable displays that exhibit the aforementioned memory effect can be grouped into two major classes, namely compensated and uncompensated. In a compensated waveform, all of the pulses are precisely adjusted to account for any memory effect in the pixel. For example, a pixel undergoing a series of transitions through gray scale levels 1-3-4-2 might receive a slightly different impulse for the 4-2 transition than a pixel that undergoes a transition series 1-2-4-2. Such impulse compensation could occur by adjusting the pulse length, the voltage, or by otherwise changing the V(t) profile of the pulses. In an uncompensated waveform, no attempt is made to account for any prior state information (other than the initial state). In an uncompensated waveform, all pixels undergoing the 4-2 transition would receive precisely the same pulse. For an uncompensated waveform to work successfully, one of two criteria must be met. Either the electro-optic material must not exhibit a memory effect in its switching behavior, or each transition must effectively eliminate any memory effect on the pixel. In general, uncompensated waveforms are best suited for use with systems capable of only coarse impulse resolution. Examples would be a display with tri-level drivers, or a display capable of only 2-3 bits of voltage modulation. A compensated waveform requires fine impulse adjustments, which are not possible with these systems. Obviously, while a coarse-impulse system is preferably restricted to uncompensated waveforms, a system with fine impulse adjustment can implement either type of waveform. The simplest uncompensated waveform is 1-bit general image flow (1-bit GIF). In 1-bit GIF, the display transitions smoothly from one pure black-and-white image to the next. The transition rule for this sequence can be stated simply: if a pixel is switching from white to black, then apply an impulse I. If it is switching from black to white, apply the impulse of the opposite polarity, −I. If a pixel remains in the same state, then no impulse is applied to that pixel. As previously stated, the mapping of the impulse polarity to the voltage polarity of the system will depend upon the response function of the material. Another uncompensated waveform that is capable of producing grayscale images is the uncompensated n-prepulse slide show (n-PP SS). The uncompensated slide show waveform has three basic sections. First, the pixels are erased to a uniform optical state, typically either white or black. Next, the pixels are driven back and forth between two optical states, again typically white and black. Finally, the pixel is addressed to a new optical state, which may be one of several gray states. The final (or writing) pulse is referred to as the addressing pulse, and the other pulses (the first (or erasing) pulse and the intervening (or blanking) pulses) are collectively referred to as prepulses. A waveform of this type will be described below with reference to FIGS. 9 and 10. Prepulse slide show waveforms can be divided into two basic forms, those with an odd number of prepulses, and those with an even number of prepulses. For the odd-prepulse case, the erasing pulse may be equal in impulse and opposite in polarity to the immediately previous writing pulse (again, see FIG. 9 and discussion thereof below). In other words, if the pixel is written to gray from black, the erasing pulse will take the pixel back to the black state. In the even-prepulse case, the erasing pulse should be of the same polarity as the previous writing pulse, and the sum of the impulses of the previous writing pulse and the erasing pulse should be equal to the impulse necessary to fully transition from black to white. In other words, if a pixel is written from black in the even-prepulse case, then it must be erased to white. After the erasing pulse, the waveform includes either zero or an even number of blanking pulses. These blanking pulses are typically pulses of equal impulse and opposite polarity, arranged so that the first pulse is of opposite polarity to the erasing pulse. These pulses will generally be equal in impulse to a full black-white pulse, but this is not necessarily the case. It is also only necessary that pairs of pulses have equal and opposite impulses it is possible that there may be pairs of widely varying impulses chained together, i.e. +I, −I, +0.1I, −0.1I, +4I, −4I. The last pulse to be applied is the writing pulse. The impulse of this pulse is chosen based only upon the desired optical state (not upon the current state, or any prior state). In general, but not necessarily, the pulse will increase or decrease monotonically with gray state value. Since this waveform is specifically designed for use with coarse impulse systems, the choice of the writing pulse will generally involve mapping a set of desired gray states onto a small number of possible impulse choices, e.g. 4 gray states onto 9 possible applied impulses. Examination of either the even or odd form of the uncompensated n-prepulse slide show waveform will reveal that the writing pulse always begins from the same direction, i.e. either from black or from white. This is an important feature of this waveform. Since the principle of the uncompensated waveform is that the pulse length can not be compensated accurately to ensure that pixels reach the same optical state, one cannot to expect to reach an identical optical state when approaching from opposite extreme optical states (black or white). Accordingly, there are two possible polarities for either of these forms, which can be labeled “from black” and “from white.” One major shortcoming of this type of waveform is that it has large-amplitude optical flashes between images. This can be improved by shifting the update sequence by one superframe time for half of the pixels, and interleaving the pixels at high resolution, as discussed below with reference to FIGS. 9 and 10. Possible patterns include every other row, every other column, or a checkerboard pattern. Note, this does not mean using the opposite polarity, i.e. “from black” versus “from white”, since this would result in non-matching gray scales on neighboring pixels. Instead, this can be accomplished by delaying the start of the update by one “superframe” (a grouping of frames equivalent to the maximum length of a black-white update) for half of the pixels (i.e. the first set of pixels completes the erase pulse, then the second set of pixels begin the erase pulse as the first set of pixels begin the first blanking pulse). This will require the addition of one superframe for the total update time, to allow for this synchronization. Limited Transitions Method of the Present Invention To avoid the aforementioned flashing problems of the drive schemes shown in FIGS. 9 and 10, while also avoiding the problems of general grayscale image flow previously discussed, it is advantageous, in accordance with the limited transitions method of the present invention, to arrange the drive scheme so that any given pixel can only undergo a predetermined maximum number (at least one) of gray scale transitions before passing through one extreme optical state (black or white). A transition away from the extreme optical state start from an accurately known optical state, in effect canceling out any previously accumulated errors. Various techniques for minimizing the optical effects of such passage of pixels through extreme optical states (such as flashing of the display) are discussed below. Before describing the limited transitions method of the present invention in detail, other ways of reducing the flashing problem will first be described. A first, simple drive scheme will now be described with reference to a simple two-bit gray scale system having black (level 0), dark gray (level 1), light gray (level 2) and white (level 3) optical states, transitions being effected using a pulse width modulation technique, and a look-up table for transitions as set out in Table 5 below. TABLE 5 Transition Impulse Transition Impulse 0-0 0 0-0 0 0-1 n 1-0 −n 0-2 2n 2-0 −2n 0-3 3n 3-0 −3n where n is a number dependent upon the specific display, and −n indicates a pulse having the same length as a pulse n but of opposite polarity. It will further be assumed that at the end of the reset pulse 304 in FIG. 8 all the pixels of the display are black (level 0). Since, as described below, all transitions take place through an intervening black state, the only transitions effected are those to or from this black state. Thus, the size of the necessary look-up table is significantly reduced, and obviously the factor by which look-up table size is thus reduced increases with the number of gray levels of the display. FIG. 9 shows the transitions of one pixel associated with the drive scheme of FIG. 8. At the beginning of the reset step 304, the pixel is in some arbitrary gray state. During the reset step 304, the pixel is driven alternately to three black states and two intervening white states, ending in its black state. The pixel is then, at 306, written with the appropriate gray level for a first image, assumed to be level 1. The pixel remains at this level for some time during which the same image is displayed; the length of this display period is greatly reduced in FIG. 9 for ease of illustration. At some point, a new image needs to be written, and at this point, the pixel is returned to black (level 0) in erase step 308, and is then subjected, in a second reset step designated 304′, to six reset pulses, alternately white and black, so that at the end of this reset step 304′, the pixel has returned to its black state. Finally, in a second writing step designated 306′, the pixel is written with the appropriate gray level for a second image, assumed to be level 2. Numerous variations of the drive scheme shown in FIG. 9 are of course possible. One useful variation is shown in FIG. 10. The steps 304, 306 and 308 shown in FIG. 10 are identical to those shown in FIG. 9. However, in step 304′,five reset pulses are used (obviously a different odd number of pulses could also be used), so that at the end of step 304′, the pixel is in its white state (level 3), and in the second writing step 306′, writing of the pixel is effected from this white state rather than the black state as in FIG. 9. Successive images are then written alternately from black and white states of the pixel. In a further variation of the drive schemes shown in FIGS. 9 and 10, erase step 308 is effected to as to drive the pixel white (level 3) rather than black. An even number of reset pulses are then applied to that the pixel ends the reset step in a white state, and the second image is written from this white state. As with the drive scheme shown in FIG. 10, in this scheme successive images are written alternately from black and white states of the pixel. It will be appreciated that in all the foregoing schemes, the number and duration of the reset pulses can be varied depending upon the characteristics of the electro-optic medium used. Similarly, voltage modulation rather than pulse width modulation may be used to vary the impulse applied to the pixel. The black and white flashes which appear on the display during the reset steps of the drive schemes described above are of course visible to the user and may be objectionable to many users. To lessen the visual effect of such reset steps, it is convenient to divide the pixels of the display into two (or more) groups and to apply different types of reset pulses to the different groups. More specifically, if it necessary to use reset pulses which drive any given pixel alternately black and white, it is convenient to divide the pixels into at least two groups and to arrange the drive scheme so that one group of pixels are driven white at the same time that another group are driven black. Provided the spatial distribution of the two groups is chosen carefully and the pixels are sufficiently small, the user will experience the reset step as an interval of gray on the display (with perhaps some slight flicker), and such a gray interval is typically less objectionable than a series of black and white flashes. For example, in one form of such a “two group reset” step, the pixel in odd-numbered columns may be assigned to one “odd” group and the pixels in the even-numbered columns to the second “even” group. The odd pixels could then make use of the drive scheme shown in FIG. 9, while the even pixels could make use of a variant of this drive scheme in which, during the erase step, the pixels are driven to a white rather a black state. Both groups of pixels would then be subjected to an even number of reset pulses during reset step 304′, so that the reset pulses for the two groups are essentially 180° out of phase, and the display appears gray throughout this reset step. Finally, during the writing of the second image at step 306′, the odd pixels are driven from black to their final state, while the even pixels are driven from white to their final state. In order to ensure that every pixel is reset in the same manner over the long term (and thus that the manner of resetting does not introduce any artifacts on to the display), it is advantageous for the controller to switch the drive schemes between successive images, so that as a series of new images are written to the display, each pixel is written to its final state alternately from black and white states. Obviously, a similar scheme can be used in which the pixels in odd-numbered rows form the first group and the pixels in even-numbered rows the second group. In a further similar drive scheme, the first group comprises pixels in odd-numbered columns and odd-numbered rows, and even-numbered columns and even-numbered rows, while the second group comprises in odd-numbered columns and even-numbered rows, and even-numbered columns and odd-numbered rows, so that the two groups are disposed in a checkerboard fashion. Instead of or in addition to dividing the pixels into two groups and arranging for the reset pulses in one group to be 180° out of phase with those of the other group, the pixels may be divided into groups which use different reset steps differing in number and frequency of pulses. For example, one group could use the six pulse reset sequence shown in FIG. 9, while the second could use a similar sequence having twelve pulses of twice the frequency. In a more elaborate scheme, the pixels could be divided into four groups, with the first and second groups using the six pulse scheme but 180° out of phase with each other, while the third and fourth groups use the twelve pulse scheme but 180° out of phase with each other. In accordance with the limited transitions method of the present invention, further reductions in flashing problems may be effected by using a drive scheme which permits any given to assume a non-zero but limited number of successive gray states before touching an optical rail. In such a drive scheme, when the display is rewritten to display a new image thereon, any pixel, which has undergone a number of transitions exceeding a predetermined value without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state. In a preferred form of such a drive scheme, a pixel driven to an extreme optical state is driven to the extreme optical state which is closer in gray level to the optical state desired after the transition, assuming of course that this desired optical state is not one of the extreme optical states. Also, in a preferred form of such a drive scheme using a look-up table as previously described, the maximum number of transitions which a pixel is allowed to undergo without touching an optical rail (extreme optical state) is set equal to the number of prior optical states taken into account in the transition matrix; such a method requires no extra controller logic or memory. Driving methods which limit the maximum number of transitions before touching an optical rail need not significantly increase the time taken for a complete rewriting of the display. For example, consider a four gray level (2 bit) display in which a transition from white to black or vice versa takes 200 msec, so that a general grayscale image flow drive scheme takes this time to completely rewrite the display. The only case where a transition needs to be modified in such a display is when a pixel is repeatedly toggled between the two central gray levels. If such a pixel is toggled between the two central gray levels for a number of transitions which exceeds the predetermined number, the limited transitions method of the present invention requires that the next toggling be effected via one optical rail (extreme optical state). It has been found that in such a case the transition to the optical rail takes about 70 msec, while the subsequent transition to the gray level takes about 130 msec, so that the total transition time is only about 200 msec. Thus, the present limited transitions method does not require any increase in transition time as compared with general grayscale image flow. A limited transitions drive method which reduces the objectionable effects of reset steps will now be described with reference to FIGS. 11A and 11B. In this scheme, the pixels are again divided into two groups, with the first (even) group following the drive scheme shown in FIG. 11A and the second (odd) group following the drive scheme shown in FIG. 11B. Also in this scheme, all the gray levels intermediate black and white are divided into a first group of contiguous dark gray levels adjacent the black level, and a second group of contiguous light gray levels adjacent the white level, this division being the same for both groups of pixels. Desirably but not essentially, there are the same number of gray levels in these two groups; if there are an odd number of gray levels, the central level may be arbitrarily assigned to either group. For ease of illustration, FIGS. 11A and 11B show this drive scheme applied to an eight-level gray scale display, the levels being designated 0 (black) to 7 (white); gray levels 1, 2 and 3 are dark gray levels and gray levels 4, 5 and 6 are light gray levels. In the drive scheme of FIGS. 11A and 11B, gray to gray transitions are handled according to the following rules: (a) in the first, even group of pixels, in a transition to a dark gray level, the last pulse applied is always a white-going pulse (i.e., a pulse having a polarity which tends to drive the pixel from its black state to its white state), whereas in a transition to a light gray level, the last pulse applied is always a black-going pulse; (b) in the second, odd group of pixels, in a transition to a dark gray level, the last pulse applied is always a black-going pulse, whereas in a transition to a light gray level, the last pulse applied is always a white-going pulse; (c) in all cases, a black-going pulse may only succeed a white-going pulse after a white state has been attained, and a white-going pulse may only succeed a black-going pulse after a black state has been attained; and (d) even pixels may not be driven from a dark gray level to black by a single black-going pulse nor odd pixels from a light gray level to white using a single white-going pulse. (Obviously, in all cases, a white state can only be achieved using a final white-going pulse and a black state can only be achieved using a final black-going pulse.) The application of these rules allows each gray to gray transition to be effected using a maximum of three successive pulses. For example, FIG. 11A shows an even pixel undergoing a transition from black (level 0) to gray level 1. This is achieved with a single white-going pulse (shown of course with a positive gradient in FIG. 11A) designated 1102. Next, the pixel is driven to gray level 3. Since gray level 3 is a dark gray level, according to rule (a) it must be reached by a white-going pulse, and the level I/level 3 transition can thus be handled by a single white-going pulse 1104, which has an impulse different from that of pulse 1102. The pixel is now driven to gray level 6. Since this is a light gray level, it must, by rule (a) be reached by a black-going pulse. Accordingly, application of rules (a) and (c) requires that this level 3/level 6 transition be effected by a two-pulse sequence, namely a first white-going pulse 1106, which drives the pixel white (level 7), followed by a second black-going pulse 1108, which drives the pixel from level 7 to the desired level 6. The pixel is next driven to gray level 4. Since this is a light gray level, by an argument exactly similar to that employed for the level 1/level 3 transition discussed earlier, the level 6/level 4 transition is effected by a single black-going pulse 1110. The next transition is to level 3. Since this is a dark gray level, by an argument exactly similar to that employed for the level 3/level 6 transition discussed earlier, the level 4/level 3 transition is handled by a two-pulse sequence, namely a first black-going pulse 1112, which drives the pixel black (level 0), followed by a second white-going pulse 1114, which drives the pixels from level 0 to the desired level 3. The final transition shown in FIG. 11A is from level 3 to level 1. Since level 1 is a dark gray level, it must, according to rule (a) be approached by a white-going pulse. Accordingly, applying rules (a) and (c), the level 3/level 1 transition must be handled by a three-pulse sequence comprising a first white-going pulse 1116, which drives the pixel white (level 7), a second black-going pulse 1118, which drives the pixel black (level 0), and a third white-going pulse 1120, which drives the pixel from black to the desired level 1 state. FIG. 11B shows an odd pixel effecting the same 0-1-3-6-4-3-1 sequence of gray states as the even pixel in FIG. 11A. It will be seen, however, that the pulse sequences employed are very different. Rule (b) requires that level 1, a dark gray level, be approached by a black-going pulse. Hence, the 0-1 transition is effected by a first white-going pulse 1122, which drives the pixel white (level 7), followed by a black-going pulse 1124, which drives the pixel from level 7 to the desired level 1. The 1-3 transition requires a three-pulse sequence, a first black-going pulse 1126, which drives the pixel black (level 0), a second white-going pulse 1128, which drives the pixel white (level 7), and a third black-going pulse 1130, which drives the pixel from level 7 to the desired level 3. The next transition is to level 6 is a light gray level, which according to rule (b) is approached by a white-going pulse, the level 3/level 6 transition is effected by a two-pulse sequence comprising a black-going pulse 1132, which drives the pixel black (level 0), and a white-going pulse 1134, which drives the pixel to the desired level 6. The level 6/level 4 transition is effected by a three-pulse sequence, namely a white-going pulse 1136, which drives the pixel white (level 7), a black-going pulse 1138, which drives the pixel black (level 0) and a white-going pulse 1140, which drives the pixel to the desired level 4. The level 4/level transition 3 transition is effected by a two-pulse sequence comprising a white-going pulse 1142, which drives the pixel white (level 7), followed by a black-going pulse 1144, which drives the pixel to the desired level 3. Finally, the level 3/level 1 transition is effected by a single black-going pulse 1146. It will be seen from FIGS. 11A and 11B that this drive scheme ensures that each pixel follows a “sawtooth” pattern in which the pixel travels from black to white without change of direction (although obviously the pixel may rest at any intermediate gray level for a short or long period), and thereafter travels from white to black without change of direction. Thus, rules (c) and (d) above may be replaced by a single rule (e) as follows: (e) once a pixel has been driven from one extreme optical state (i.e., white or black) towards the opposed extreme optical state by a pulse of one polarity, the pixel may not receive a pulse of the opposed polarity until it has reached the aforesaid opposed extreme optical state. Thus, this drive scheme is a “rail-stabilized gray scale” or “RSGS” drive scheme. Such a RSGS drive scheme is a special case of a limited transitions drive scheme which ensures that a pixel can only undergo, at most, a number of transitions equal to N/2 (or more accurately (N−1)/2) transitions, where N is the total number of gray levels capable of being displayed, without requiring a transition to take place via an optical rail. Such a drive scheme prevents slight errors in individual transitions (caused, for example, by unavoidable minor fluctuations in voltages applied by drivers) accumulating indefinitely to the point where serious distortion of a gray scale image is apparent to an observer. Furthermore, this drive scheme is designed so that even and odd pixels always approach a given intermediate gray level from opposed directions, i.e., the final pulse of the sequence is white-going in one case and black-going in the other. If a substantial area of the display, containing substantially equal numbers of even and odd pixels, is being written to a single gray level, this “opposed directions” feature minimizes flashing of the area. For reasons similar to those discussed above relating to other drive schemes which divide pixels into two discrete groups, when implementing the sawtooth drive scheme of FIGS. 11A and 11B, careful attention should be paid to the arrangements of the pixels in the even and odd groups. This arrangement will desirably ensure that any substantially contiguous area of the display will contain a substantially equal number of odd and even pixels, and that the maximum size of a contiguous block of pixels of the same group is sufficiently small not to be readily discernable by an average observer. As already discussed, arranging the two groups of pixels in a checkerboard pattern meets these requirements. Stochastic screening techniques may also be employed to arrange the pixels of the two groups. However, in this sawtooth drive scheme, use of a checkerboard pattern tends to increase the energy consumption of the display. In any given column of such a pattern, adjacent pixels will belong to opposite groups, and in a contiguous area of substantial size in which all pixels are undergoing the same gray level transition (a not uncommon situation), the adjacent pixels will tend to require impulses of opposite polarity at any given time. Applying impulses of opposite polarity to consecutive pixels in any column requires discharging and recharging the column (source) electrodes of the display as each new line is written. It is well known to those skilled in driving active matrix displays that discharging and recharging column electrodes is a major factor in the energy consumption of a display. Hence, a checkerboard arrangement tends to increase the energy consumption of the display. A reasonable compromise between energy consumption and the desire to avoid large contiguous areas of pixels of the same group is to have pixels of each group assigned to rectangles, the pixels of which all lie in the same column but extend for several pixels along that column. With such an arrangement, when rewriting areas having the same gray level, discharging and recharging of the column electrodes will only be necessary when shifting from one rectangle to the next. Desirably, the rectangles are 1×4 pixels, and are arranged so that rectangles in adjacent columns do not end on the same row, i.e., the rectangles in adjacent columns should have differing “phases”. The assignment of rectangles in columns to phases may be effected either randomly or in a cyclic manner. One advantage of the sawtooth drive scheme shown in FIGS. 11A and 11B is that any areas of the image which are monochrome are simply updated with a single pulse, either black to white or white to black, as part of the overall updating of the display. The maximum time taken for rewriting such monochrome areas is only one-half of the maximum time for rewriting areas which require gray to gray transitions, and this feature can be used to advantage for rapid updating of image features such as characters input by a user, drop-down menus etc. The controller can check whether an image update requires any gray to gray transitions; if not, the areas of the image which need rewriting can be rewritten using the rapid monochrome update mode. Thus, a user can have fast updating of input characters, drop-down menus and other user-interaction features of the display seamlessly superimposed upon a slower updating of a general grayscale image. A limited transitions drive scheme does not necessarily require the use of counters to measure the number of transitions undergone by each pixel of a display, and does not bar the use of drive schemes (such as the cyclic RSGS drive scheme already described with reference to FIGS. 11A and 11B) which require certain transitions to take place via an optical rail even if the predetermined number of transitions has not been reached, provided that the algorithm used to determine the manner of effecting transitions does not permit any pixel to undergo more than the predetermined number of transitions without touching an optical rail. Furthermore, it will be appreciated that the check on the number of transitions undergone by a given pixel without touching an optical rail need not be made at every rewriting of the image on the display, especially in the case of displays (for example in watches) which are updated at frequent intervals. For example, the check might be made on only alternate updates, provided that all pixels which either exceeded with predetermined number of transitions or might exceed this number after the next update were driven to optical rails. Another preferred limited transitions method of the invention will now be described, though by way of illustration only. This preferred method is used to operate a four gray level (2 bit) active matrix display which uses a transition matrix which takes account of only the initial and final gray levels (designated “R2” and “R1” respectively) of the transition to be effected, and no additional prior states. The display controller is a tri-level pulse width modulation (PWM) controller capable of applying −V, 0 or +V to each pixel electrode relative to the common front electrode, which is held at 0. The display controller contains two RAM image buffers. One buffer (“A”) stores the image currently on the display. Normally, the controller is in sleep mode, preserving the data in the RAM and keeping the display drivers inactive. The bistability of the electro-optic medium keeps the same image on the display. When an image update command is received, the controller loads the new image into the second buffer (“B”). Then, for each pixel of the display, the controller looks up (in FLASH memory) a multi-frame drive waveform, based on the desired final state R1 of the pixel (from buffer “B”) and the current, initial state R2 of each pixel (from buffer “A”). The data in the flash memory file is organized as a three-dimensional array of voltage values, V(R1, R2, frame), where as already indicated R1 and R2 are each integers from 1 to 4 (corresponding to the four available gray levels), and “frame” is the frame number, i.e., the number of the relevant frame within the superframe used for each transition. Typically, the superframe might be 1 second long, with each frame occupying 20 ms, so that the frame number can range from 1 to 50. Thus, the array has 4×4×50=800 entries. Since each entry in the array must be capable of representing any one of the voltage values −V, 0 and +V, typically two bits will be used to store each voltage value (array value). It will immediately be apparent that, since each of the 800 array entries may have any one of the three possible voltage values, there are a huge number of possible arrays (waveforms), the number being far too large to search exhaustively. In theory, there are 3800 or about 5×10381 possible arrays; since there are about 1078 atoms in the universe and 109 seconds in an average human lifetime, practical capabilities are at least 200 orders of magnitude short of an exhaustive search. Fortunately, existing knowledge about the behavior of electro-optic displays, and especially the need for DC balance therein, impose additional constraints upon the possible waveforms and enable the search for an optimum or near optimum waveform to be confined within practicable limits. As discussed in the aforementioned U.S. Pat. Nos. 6,504,524 and 6,531,997 and the aforementioned 2003/0137521, it is known that most, if not all, electro-optic media require direct current (DC) balanced waveforms, or deleterious effects may occur. Such effects may include damage to electrodes and long term drift (over a period of hours) of gray states over a range of several L* units when DC imbalanced waveforms are used. Accordingly, it seems prudent to make every effort to use DC balanced drive wave schemes. From what has been said above, it might at first appear that such DC balancing may not be achievable, since the impulse, and thus the current through the pixel, required for any particular gray to gray transition is substantially constant. However, this is only true to a first approximation, and it has been found empirically that, at least in the case of particle-based electrophoretic media (and the same appears to be true of other electro-optic media), the effect of (say) applying five spaced 50 msec pulses to a pixel is not the same as applying one 250 msec pulse of the same voltage. Accordingly, there is some flexibility in the current which is passed through a pixel to achieve a given transition, and this flexibility can be used to assist in achieving DC balance. For example, the look-up table can store multiple impulses for a given transition, together with a value for the total current provided by each of these impulses, and the controller can maintain, for each pixel, a register arranged to store the algebraic sum of the impulses applied to the pixel since some prior time (for example, since the pixel was last in a black state). When a specific pixel is to be driven from a white or gray state to a black state, the controller can examine the register associated with that pixel, determine the current required to DC balance the overall sequence of transitions from the previous black state to the forthcoming black state, and choose that one of the multiple stored impulses for the white/gray to black transition needed which will either accurately reduce the associated register to zero, or at least to as small a remainder as possible (in which case the associated register will retain the value of this remainder and add it to the currents applied during later transitions). It will be apparent that repeated applications of this process can achieve accurate long term DC balancing of each pixel. It is necessary to consider the precise definition of DC balance in a waveform. To determine if a waveform is DC balanced, a resistive model of the electro-optic medium is normally used. Such a model is not completely accurate, but may be assumed to be sufficiently accurate for present purposes. Using such a model, the characteristic that defines a DC balanced waveform is that the integral of the applied voltage with time (the applied impulse) is bounded. Note that the definition requires that be integral be “bounded” and not “zero.” To illustrate this point, consider a monochrome addressing waveform which uses a 300 ms×−15V square pulse to drive the transition from white to black, and a 300 ms×15V square pulse to drive the transition from black to white. This waveform is clearly DC balanced, but the integral of applied voltage is not zero at every point in time; this integral varies between 0 and ±4.5 V-sec. However, this waveform DC is balanced in as much as the integral is bounded; the integral never reaches 9 or 18 V-sec, for example. For further consideration of DC balanced waveforms, some definition of terms is advisable. The term “impulse” has already been defined as meaning the definite integral of voltage with respect to time (in V-sec) applied during a particular interval, usually an addressing pulse or pulse element. The term “impulse potential” will be used to mean the sum of all impulses applied to the display since an arbitrary starting point (typically the beginning of a series of transitions under consideration. At the starting point, the impulse potential is arbitrarily set to zero, and as impulses are applied the impulse potential rises and falls. Using these terms, the definition of DC balance is that a waveform is DC balanced if and only if the impulse potential is bounded. Having a bounded impulse potential means that one must be able to say what the impulse potential will be in each of a finite number of possible cases. For a time-independent controller (i. e., a controller in which the impulse of the waveform is influenced only by the initial and final states of the transition under consideration, and not dwell times, temperature, or other factors, such as the R1/R2 controller mentioned above), in order to show that a waveform is DC balanced, it is necessary to be able to prove that the impulse potential will be bounded after each transition in any infinitely long sequence of optical states. One sufficient condition for such proof is that the impulse potential can be expressed as a function of a fixed number of prior states, and this provides a working concept of DC balance for controllers for electro-optic displays, i.e., that the impulse potential can be expressed as a function of a finite number of prior and current optical states. Note that the impulse potential of any pixel of the display does not change from the end of one image update to the beginning of another image update, because no voltage is applied during this period. For each combination of a (finite) number of prior states, the controller applies a fixed impulse (the impulse determined by the data in the flash memory already mentioned), and these fixed impulses can be listed. To list them, it is necessary to enumerate prior state combinations back by at least the number of prior states being used in the controller (i.e. for an R1/R2 controller, the number of prior states used in the enumeration needs to be defined for all combinations of prior states two back). To define the impulse potential at the end of the update, knowing the fixed impulse applied during the impulse, one needs to be able to define the impulse potential at the beginning of the update for all states in the enumeration. This means that the net impulse applied by a waveform must be a function of one fewer prior state than the number needed to uniquely define the impulse potential at the end. To translate this to the problem of determining the optimum waveform to be applied by a controller, this means that the impulse potential for a waveform must be a function of one fewer prior states than the number of states used to determine the waveform. For example, if a controller has impulse data determined by three states, R1, R2, and R3 (where R3 is the gray level immediately prior to the initial gray level for the transition under consideration), each combination of R1 and R2 must leave the electro-optic medium at the same impulse potential, independent of R3. In other words, the controller has to “know” the impulse potential of the electro-optic medium when it starts the transition being considered, so it can apply the right impulse to produce the proper value of impulse potential following the transition. If the impulse potential in the above example were allowed to vary based on all of R1, R2, and R3, then, in the next transition, there would be no way for the controller to “know” the starting impulse potential, since the R3 information previously used would have been discarded. As already indicated, the limited transitions method of the present invention is preferably carried out using an R1/R2 controller (i.e., a controller in which the impulse applied during any transition depends only upon the initial and final gray levels of that transition), and from the foregoing discussion it will be seen that in such a controller the impulse potential must be uniquely defined as a function of R1 only. Further complications in determining the optimum waveform arise from a phenomenon which may be called “impulse hysteresis”. Except in rare situations of extreme overdrive at the optical rails, electro-optic media driven with voltage of one polarity always get blacker, and electro-optic medium driven with voltage of the opposite polarity always get whiter. However, for some electro-optic media, and in particular some encapsulated electro-optic media, the variation of optical state with impulse displays hysteresis; as the medium is driven further toward white, the optical change per applied impulse unit decreases, but if the polarity of the applied voltage is abruptly reversed so that the display is driven in the opposed direction, the optical change per impulse unit abruptly increases. In other words the magnitude of the optical change per impulse unit is strongly dependent not only upon the current optical state but also upon the direction of change of the optical state. This impulse hysteresis produces an inherent “restoring force” tending to bring the electro-optic medium towards middle gray levels, and confounds efforts to drive the medium from state to state with unipolar pulses (as in general gray scale image flow) while still maintaining DC balance. As pulses are applied, the medium rides the three-dimensional R1/R2/impulse hysteresis surface until it reaches an equilibrium. This equilibrium is fixed for each pulse length and is generally in the center of the optical range. For example, it has been found empirically that driving one encapsulated four gray level electro-optic medium from black to dark gray required a 100 ms×−15 V unipolar impulse, but driving it back from dark gray to black required a 300 ms×15 V unipolar impulse. This waveform was not DC balanced, for obvious reasons. A solution to the impulse hysteresis problem is to use a bipolar drive, that is to say to drive the electro-optic medium on a (potentially) non-direct path from one gray level to the next, first applying an impulse to drive the pixel into either optical rail as required to maintain DC balance and then applying a second impulse to reach the desired optical state. For example, in the above situation, one could go from black to dark gray by applying 100 ms×−15 V of impulse, but go back from dark gray to white by first applying additional negative voltage, then positive voltage, riding the R1/R2 impulse curve down to the black state. Such indirect transitions also avoid the problem of accumulation of errors by rail stabilization of gray scale, as already discussed. The impulse hysteresis phenomenon and the prior state dependence of electro-optic media, as discussed above and in the aforementioned patents and applications, require that the waveform for each transition vary depending upon the prior state history of the pixel being considered. As described in the aforementioned 2003/0137521, the optimum waveform for each transition may be determined (i.e., the transition table corresponding to the aforementioned data array may be “tuned”) by using an initial “guessed” transition matrix to create a waveform, which is used to address the electro-optic medium through a fixed, typically pseudo-random or prior-state-complete series of optical states. A program subtracts the actual optical state achieved in each prior state combination from the target gray states for the same combination to compute an error matrix, which is the same dimensions as the transition matrix. Each element in the error matrix corresponds to an element in the transition matrix. If an element in the transition matrix is too high, the corresponding element in the error matrix will be pushed higher. PID (proportional-integral-differential) control can then be used to drive the error matrix toward zero. There are cross-terms (each element in the transition matrix affects more than one element in the error matrix) but these effects are minor and tend to decrease as the magnitudes of the values in the error matrix decrease, as the tuning proceeds through multiple iterations. (Note that sometimes the I or D constants of the PID controller may be set to 0, yielding PI, PD, or P control.) When this tuning process is completed, it is found that a certain number of prior optical states need to be in the transition matrix to achieve a certain gray level precision performance. For example, using this process with one specific encapsulated electro-optic medium yielded a waveform in which the controller recorded one more prior optical state than was in the transition matrix, and calculated the impulse in the first section of the waveform using arithmetic to ensure DC balance. In this waveform, the impulse potential was allowed to be different for each prior state combination covered by the transition matrix. The correlation between the number of dimensions in the transition matrix (“TM dimension”) and the maximum optical error for this waveform was found to be as set out in Table 6 below: TABLE 6 TM Dimension Maximum Optical Error (L*) 1 10.6 2 3.8 3 2.1 4 1.7 Since limit of visual perception for the average observer is around 1 L* unit, the data in this table indicate that it is very useful to have more than one dimension in the transition matrix, with a two dimensional matrix being superior to a one dimensional, a three dimensional matrix being superior to a two dimensional, etc. Having regard to all of the foregoing points, a preferred waveform was devised for the R1/R2 2 bit gray scale controller already mentioned. This waveform maintained fixed impulse potentials for each final optical state R1, but used a two dimensional transition matrix. It was rail stabilized, to reduce the accumulation of error, and was designed to have low divergence during toggling because it respected the impulse hysteresis curve. In the notation used below, numbers represent impulse. Negative impulse was applied by applying −V (i.e. −15V) for a given time, and positive impulse was applied by applying +V for a given time (i.e., the waveform was pulse width modulated), so that the magnitude of the volt-time product equaled the magnitude of the impulse. Voltage modulation could alternatively be used. In the preferred waveform, the following sequence of impulses was applied during each update, reading from left to right in time: −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) where “IP(Rx)” represents the relevant value from an impulse potential matrix (in this case a vector) having one value for each gray level, and TM(R1,R2) represents the relevant value from a transition matrix having one value for each R1/R2 combination. TM(R1,R2) can of course be negative for certain values of R1 and R2. (As already noted, for convenience, impulse sequences of this type may hereinafter be abbreviated as “−x/ΔIP/x” sequences.) The values in the transition matrix could be adjusted as desired, without worrying about DC balance, because the net impulse of the first and third sections of this waveform is always zero. The difference in impulse potential between the initial and final state is applied in the middle section of the waveform. Empirically, it has been found that the final drive pulse almost always has more effect on the final gray level than the initial pulse, so the transition matrix for this waveform can be tuned with the same PID approach described above. The values set for the impulse potentials influence the update speed of the waveform for fixed final gray levels. For example, all the impulse potentials could be set to zero, but this results in a long update time, because the final drive pulse (third section) is always countered by an equally long initial pulse (first section). Thus, the final drive pulse, in this case, cannot be longer than half the total update time. By careful selection of impulse potentials, it is possible to use a much larger fraction of the total update time for the final pulse; for example, one can achieve final drive pulses occupying more than half, and as much as 80% of the total maximum update time. Preferably, the lengths of the various pulses are selected by computer, using a gradient following optimization method, like PID control, finite difference combination evaluation, etc. As noted in Paragraphs [0073] to [0077] of the aforementioned 2003/0137521 and above, transitions in electro-optic media are typically temperature sensitive, and it has been found that the uncompensated stability of gray levels versus temperature is increased when all of the transitions to a particular gray level always come from the same optical rail. The reason for this is straightforward; as the temperature varies, the switching speed of the electro-optic medium becomes gets faster or slower. Suppose that, in a 2 bit gray level display, the dark gray to light gray transition bounces off the black rail, but the white to light gray transition bounces off the white rail. If the switching speed of the medium becomes slower, the light gray state addressed from black will become darker, but the light gray state addressed from black will become lighter. Thus, it is important for a temperature stable waveform that a given gray level always be approached from the same “side”, i.e., that the final pulse of the waveform always be of the same polarity. In the preferred drive scheme described above using the −TM(R1,R2) IP(R1)−IP(R2) TM(R1,R2) sequence, this requires choosing the TM(R1,R2) values so that the sign of each value is dependent only on R1, at least for some gray levels. One preferred approach is to allow the TM values to be of either sign for the black and white states, but positive only for light gray, and negative only for dark gray, and thus that the intermediate gray levels be approached only from the nearer optical rail. This preferred waveform is fully compatible with techniques such as insertion of short pause periods into the waveform to increase impulse resolution, as described below. As already indicated, the aforementioned −x/ΔIP/x pulse sequences may be modified to contain additional pulses. One such modification allows the inclusion of an additional class of pulses, hereinafter referred to as “y” pulses. “y” pulses are characterized by being of the form [+y][−y], where y is an impulse value, and may be either negative or positive (in other words, the form [−y][+y] is equally valid. The y pulse is distinct from the previously-described “x” pulses, in that the [−x] and [+x] halves of the “x” pulse pair are disposed before and after the ΔIP pulse, whereas the “y” pulses can be disposed at other locations within the pulse sequence. A second such modification adds a 0 V “pulse” (i.e., a period when no voltage is applied to the relevant pixel) at an arbitrary point within the pulse sequence to improve the performance of that sequence, by, for example, shifting the gray level resulting from the transition up or down by a small amount, or reducing or changing the impact of prior state information on the final state of the pixel. Such 0 V sections may be inserted either between the different pulse elements, or in the middle of a single pulse element. A preferred method for constructing a rail-stabilized waveform, using a transition table as described in the aforementioned 2003/0137521 is as follows: (a) set the value (typically derived empirically) of the impulse potential for each gray level, and insert into the transition table the appropriate ΔIP pulse for each transition; (b) for each transition, pick a value for x, and insert a −x pulse before, and a +x pulse after, the ΔIP pulse (as already noted, the value of x may be negative, so the −x and +x pulses can have either polarity); (c) for each transition, pick a value for y, and insert a −y and +y pulses into the pulse sequence. The −y/+y pulse combination may be inserted into the sequence at any pulse boundary, for example before the −x pulse, before the ΔIP pulse, before the +x pulse, or after the +x pulse; (d) for each transition, insert n frames, where n=0 or more, of 0 V at any point or points in the pulse sequence; and (e) repeat the above steps as many times as desired, until the waveform performance reaches the desired level. This process will be illustrated with reference to the accompanying drawings. FIG. 12 shows the basic −x/ΔIP/+x structure of the waveform for one transition, it being assumed for the sake of illustration that the values of both x and ΔIP are positive. Unless it is desired to provide a 0 V interval between the ΔIP and the +x pulses, it is not necessary to reduce the voltage applied at the junction between these two pulses, so that the ΔIP and +x pulses form, in effect, one long positive pulse. FIG. 13 illustrates symbolically the insertion of a [−y][+y] pair of pulses into the basic −x/ΔIP/+x waveform shown in FIG. 12. The −y and +y pulses do not have to be consecutive, but can be inserted at different places into the original waveform. There are two especially advantageous special cases. In the first special case, the “−y, +y” pulse pair is placed at the beginning of the −x/ΔIP/+x waveform, before the −x pulse, to produce the waveform shown in FIG. 14. It has been found that, when y and x are of opposite sign, as illustrated in FIG. 14, the final optical state can be finely tuned by even moderately coarse adjustment of the duration y. Thus, the value of x can be adjusted for coarse control and the value of y for final control of the final optical state of the electro-optic medium. This is believed to happen because the y pulse augments the −x pulse, thus changing the degree to which the electro-optic medium is pushed into one of its optical rails. The degree of pushing into one of the optical rails is known to give fine adjustment of the final optical state after a pulse away from that optical rail (in this case, provided by the x pulse). In a second special case, illustrated in FIG. 15, the −y pulse is again placed at the beginning of the −x/ΔIP/+x waveform, before the −x pulse, but the +y pulse is placed at the end of the waveform, after the +x pulse. In this type of waveform, the final y pulse provides coarse tuning because the final optical state is very sensitive to the magnitude of y. The x pulse provides a finer tuning, since the final optical state typically does not depend as strongly on the magnitude of the drive into the optical rail. As already indicated, more than one pair of “y” pulses may be inserted into the basic −x/ΔIP/+x waveform to allow “fine tuning” of gray scale levels of the electro-optic medium, and the impulses of such multiple pairs of “y” pulses may differ from one another. FIG. 16 illustrates symbolically, in a manner similar to that of FIG. 13, the insertion of a second pair of y-type pulses (denoted “−z”, “+z”) into the waveform of FIG. 15. It will readily be apparent that since the −z and +z pulses can be introduced at any pulse boundary of the waveform shown in FIG. 15, a large number of different waveforms can result from the introduction of the −z and +z pulses. A preferred resulting waveform is shown in FIG. 17; this type of waveform is useful for fine tuning of the final optical state, for the following reasons. Consider the situation without the −z and +z pulses (i.e. the FIG. 15 waveform discussed above). The x pulse element is used for fine tuning, and the final optical state can be decreased by increasing x and increased by decreasing x. However, it is undesirable to decrease x beyond a certain point because then the electro-optic medium is not brought sufficiently close to an optical rail, as required for stability of the waveform. To avoid this problem, instead of decreasing x, one can (in effect) increase the −x pulse without changing the +x pulse by adding the −z, +z pulse pair as shown in FIG. 17, with z having the opposite sign from x. The +z pulse augments the −x pulse, while the −z pulse maintains the transition at the desired net impulse, thus maintaining an overall DC balanced transition table. In the limited transitions waveform scheme of the present invention, it is acceptable for the “diagonal elements” (the transition table elements corresponding to null transitions in which the initial and final gray levels are the same, so called because in a normal matrix representation of a transition table such elements lie on the leading diagonal; such diagonal elements have ΔIP=0) to contain both x and y pulses. Any given transition table element may contain zero or more sets of x and/or y pulses. The limited transitions method of the present invention may also make use of pause periods between adjacent frames of a transition; such pause periods are discussed in more detail below with reference to the interrupted scanning method of the present invention. Typically, in an active matrix display, the pixels are divided into a series of groups (normally a plurality of rows), each of these plurality of groups is selected in succession (i.e., typically the rows of the matrix are scanned) and there is applied to each of the pixels in the selected group either a drive voltage or a non-drive voltage. The scanning of all the groups of pixels is completed within a frame period. The scanning of the groups of pixels is repeated, and, in a typical electro-optic display, the scanning will be repeated more than once during the group of frames (conveniently referred to as a superframe) required for a complete rewriting of the display. Normally, a fixed scan rate is used for updating, for example 50 Hz, which allows for 20 msec frames. However, this frame length may provide insufficient resolution for optimal waveform performance. In many cases, frames of length t/2 are desirable, for example 10 msec frames in a normally 20 msec frame length waveform. It is possible to combine frames of differing delay times to generate a pulse resolution of n/2. To take one specific case a single frame of length 1.5*t may be inserted at the beginning of the waveform, and a similar frame at the end of the waveform (immediately before the terminating 0 V frame, which should occur at the ordinary frame rate and which is normally used at the end of the waveform to prevent undesirable effects caused by varying residual voltages on pixels). The two longer frames can be realized by simply adding a 0.5*t delay time between the scanning of two adjacent frames. The waveform would then have the structure: t ms frame: t/2 ms delay: t ms frame [. . . ] t ms frame: t/2 ms delay: t ms frame (all outputs to 0V) For a normal frame length of 20 msec, the initial and final frames plus their respective delays would amount to 30 msec each. Using this waveform, structure, the initial and final pulses are allowed to vary by 10 msec in length, by using the following algorithm: (a) If the length of the initial pulse is evenly divisible by t, then the first frame consists of a 0 V drive, and a corresponding number of frames of t ms are activated to achieve the desired pulse length; or (b) If the length of the initial pulse leaves a remainder of t/2 when divided by t, then the first frame of 1.5*t is active, and a corresponding number of t msec frames following the initial frame are activated to achieve the desired pulse length. The same algorithm is followed for the final pulse. Note that the initial and final pulses must be start- and end-justified, respectively, for this algorithm to work properly. In addition, in order to maintain DC balance, the initial and final pulses may be corresponding parts of a −x/+x pair. Whether or not pause periods are employed, it has been found that the effect of the waveform used to effect a transition is modified by the presence of a period of zero voltage (in effect a time delay) during or before any of the pulses in the waveform, and the limited transitions method of the present invention may include periods of zero voltage within or between successive pulses in the waveform, i.e., the waveform may be “non-contiguous” as that term is used above and in the aforementioned application Ser. No. 10/814,205. FIGS. 18 to 20 illustrate variations of the basic −x/ΔIP/+x waveform of FIG. 12 incorporating such zero voltage periods. In the waveform of FIG. 18, a time delay is inserted between the −x pulse and the ΔIP pulse. In the waveform of FIG. 19, a time delay is inserted within the ΔIP pulse, or, which amounts to the same thing, the ΔIP pulse is split into two separate pulses separated by the time delay. The waveform of FIG. 20 is similar to that of FIG. 19, except that the time delay is inserted within the +x pulse. Time delays can be incorporated into a waveform to achieve optical states not achievable without such delays. Time delays can also be used to fine-tune the final optical state. This fine-tuning ability is important, because in an active matrix drive, the time resolution of each pulse is defined by the scan rate of the display. The time resolution offered by the scan rate can be coarse enough that precise final optical states cannot be achieved without some additional means of fine tuning. Interrupted Scanning Method of the Present Invention As already mentioned, this invention provides an “interrupted scanning” method for driving an electro-optic display having a plurality of pixels divided into a plurality of groups. The method comprises selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period. The scanning of the groups of pixels is repeated during a second frame period (it being understood that any specific pixel may have the drive voltage applied during the first frame period and the non-drive voltage applied during the second frame period, or vice versa). In the interrupted scanning method invention, the scanning of the groups of pixels is interrupted during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. In this method, the first and second frame periods are typically equal in length, and the length of the pause period is typically a sub-multiple (desirably, one half, one fourth etc.) of the length of one of the frame periods. The interrupted scanning method may include multiple pause periods between different pairs of adjacent frame periods. Such multiple pause periods are preferably of substantially equal length, and the total length the multiple pause periods is preferably equal to either one complete frame period, or equal to one frame period less one pause period. For example, as discussed in more detail below, one embodiment of the first method might use multiple 20 ms frame periods, and either three or four 5 ms pause periods. In this interrupted scanning method, the groups of pixels will of course typically be the rows of a conventional row/column active matrix pixel array. The interrupted scanning method comprises selecting each of the plurality of groups of pixels in succession (i.e., typically, scanning the rows of the matrix) and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period. The scanning of the groups of pixels is repeated, and in a typical electro-optic display, the scanning will be repeated more than once during the superframe required for a complete rewriting of the display. The scanning of the groups of pixels is interrupted during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. Although a drive voltage is only applied to any specific pixel electrode for one line address time during each scan, the drive voltage persists on the pixel electrodes during the time between successive selections of the same line, only slowly decaying, so that the pixel continues to driven during the time when other lines of the matrix are being selected, and the interrupted scanning method relies upon this continued driving of the pixel during its “non-selected” time. Ignoring for the moment the slow decay of the voltage on the pixel electrode during its non-selected time, a pixel which is set to the driving voltage during the frame period immediately preceding the pause period will continue to experience the driving voltage during the pause period, so that for such a pixel the preceding frame period is in effect lengthened by the length of the pause period. On the other hand, a pixel which is set to the non-driving (typically zero) voltage during the frame period immediately preceding the pause period will continue to experience the zero voltage during the pause period. It may be desirable to adjust the length of the pause period to allow for the slow decay of the voltage on the pixel electrode in order to ensure that the total impulse delivered to the pixel during the pause period has the desired value. To take a simple example of the interrupted scanning method for purposes of illustration, consider a simple pulse width modulated drive scheme having a superframe consisting of a plurality of (say 10) 20 ms frames. Typically, the last frame of the superframe will set all pixels to the non-driving voltage, since bistable electro-optic displays are normally only driven when the displayed image is to be changed, or at relatively long intervals when it is deemed desirable to refresh the displayed image, so that each superframe will typically be followed by a lengthy period in which the display is not driven, and it is highly desirable to set all pixels to the non-driving voltage at the end of the superframe in order to prevent rapid changes in some pixels during this lengthy non-driven period. To modify such a drive scheme in accordance with the interrupted scanning method of the present invention, a 10 ms pause period may be inserted between two successive 20 ms frames, and this simple modification halves the maximum possible difference between the applied impulse and the impulse ideally needed to complete a given transition, thereby in practice approximately halving the maximum deviation in achieved gray scale level. The 10 ms pause period is conveniently inserted after the penultimate frame in each superframe but may be inserted at other points in the superframe if desired. In practice, it is desirable, in this example, not only to insert the 10 ms pause period but also to insert one additional 20 ms frame into each superframe. The unmodified drive scheme enables one to apply to any given pixel impulses of: 0, 20, 40, 60 . . . 160, 180 units application of the driving voltage for 1 ms. Thus, the maximum difference between the available impulses and the ideal impulse for a given transition is 10 units. (Since the last frame of the superframe sets all pixels to the non-driving voltage, only the first nine frames of the superframe are available for application of the driving voltage.) As already explained, any pixel which is set to the driving voltage in the frame preceding the pause period continues to experience this driving voltage for a period equal to the frame period plus the pause period, and thus experiences an impulse of 30 units instead of 20 units for this frame. Accordingly, the modified drive scheme permits one to apply to any given pixel impulses of: 0, 20, 30, 40, 50, 60 units etc. Insertion of the additional frame into the superframe is desirable to enable the modified drive scheme to deliver an impulse of exactly 180 units. Since any impulse which is an exact multiple of 20 units requires that the relevant pixel be set to the non-driving voltage during the frame preceding the pause period, achieving an impulse of exactly 180 units requires an 11-frame superframe, so that any pixel to receive the 180 impulse can be set to the driving voltage during 9 frames, to the non-driving voltage during the frame preceding the pause period, and (as always) to the non-driving voltage during the last frame of the superframe. Thus, when using the modified drive scheme, the maximum difference between the available impulses and the ideal impulse for a given transition is reduced to 5 units. (Although the modified drive scheme is not capable of applying an impulse of 10 units, in practice this is of little consequence. To produce reasonably consistent gray scale levels, the number of available impulse levels has to be substantially larger than the number of gray levels of the display, so that it is unlikely that any gray scale transition will require an impulse as small as 10 units.) The pause periods can of course be of any number and length required to achieve the desired control over the impulse applied. For example, instead of modifying the aforementioned drive scheme to include one 10 ms pause period, the drive scheme could be modified to include three 5 ms pause periods after different 20 ms drive frames, desirably with the addition to the drive scheme of three further 20 ms drive frames not followed by pause periods. This modified drive scheme permits one to apply to any given pixel impulses of: 0, 20, 25, 30, 35 . . . 170, 175, 180 units thereby reducing the maximum difference between the available impulses and the ideal impulse for a given transition is reduced to 2.5 units, a four-fold reduction as compared with the original unmodified drive scheme. The preceding discussion of the interrupted scanning method has ignored the question of polarity of the applied impulses. As discussed above and in the aforementioned 2003/0137521, bistable electro-optic media require application of impulses of both polarities. In some drive schemes, such as slide show drive schemes (cf. the discussion of FIGS. 9 and 10 above), before a new image is written to the display, all the pixels of the display are first driven to one extreme optical state, either black or white, and thereafter the pixels are driven to their final gray states by impulses of a single polarity. Such drive schemes can be modified in accordance with the interrupted scanning method in the manner already described. Other drive schemes require application of impulses of both polarities to drive the pixels to their final gray states. The impulses of the two polarities may be applied in separate frames (see, for example, Paragraphs [0128] to [0132] of the aforementioned 2003/0137521 and the discussion of Table 3 above) or, as discussed above, impulses of the two polarities may be applied in the same frames, for example using a tri-level drive scheme in which the common front electrode is held at a voltage of V/2, while individual pixel electrodes are held at 0, V/2 or V. When the impulses of the two polarities are applied in separate frames, the interrupted scanning method is desirably effected by providing at least two separate pause periods, one following a frame in which impulses of one polarity are applied and the second following a frame in which impulses of the opposed polarity are applied. However, when using a drive scheme in which impulses of both polarities are applied in the same frames, the interrupted scanning method may make use of only a single pause period since, as will be apparent from the foregoing discussion, the effect of including a pause period after a frame is to increase the magnitude of the impulse applied to any pixel to which a driving voltage was applied in the frame, regardless of the polarity of this driving voltage. Also as discussed in the aforementioned 2003/0137521 and above, many bistable electro-optic media are desirably driven with drive schemes which achieve long term direct current (DC) balance, and such DC balance is conveniently effected using a drive scheme in which a DC balance section, which does not substantially change the gray level of the pixel, is applied before the main drive section, which does change the gray level, the two sections being chosen so that the algebraic sum of the impulses applied is zero or at least very small. If the main drive section is modified in accordance with the interrupted scanning method, it is highly desirable that the DC balance section be modified to prevent the additional impulses caused by the insertion of the pause periods accumulating to cause substantial DC imbalance. However, it is not necessary that the DC balance section be modified in a manner which is an exact mirror image of the modification of the main drive section, since the DC balance section can have gaps (zero voltage frames) and most electro-optic medium are not harmed by short term DC imbalances. Thus, in the drive scheme discussed above using a single 10 ms pause period inserted among ten 20 ms frames, DC balance can be achieved by making the first frame of the drive scheme 30 ms in duration. Applying or not applying a driving voltage to a pixel during this frame brings the overall impulse to a multiple of 20 units, so that this impulse can readily be balanced later. In the drive scheme using three 5 ms pause periods, the first two frames of the drive scheme can similarly be 25 and 30 ms in duration (in either order), again bringing the overall impulse to a multiple of 20 units. From the foregoing description, it will be seen that the interrupted scanning method of the present invention requires a trade-off between increased addressing time caused by the need to include one additional frame in each superframe for each pause period inserted, and the improved control of impulse and hence gray scale produced by the method. However, the interrupted scanning method can provide very substantial improvement in impulse control with only modest increase in addressing time; for example, the drive scheme described above in which a superframe comprising ten 20 ms frames is modified to include three 5 ms pause periods yields a four-fold improvement in impulse accuracy at the cost of less than a 40 per cent increase in addressing time. Balanced Gray Level Method of the Present Invention As already mentioned, this invention also provides a balanced gray level method for driving an electro-optic display having a plurality of pixels arranged in an array. The pixels are driven with a pulse width modulated waveform capable of applying a plurality of differing impulses. Drive circuitry stores data indicating whether application of a given impulse will produce a gray level higher or lower than a desired gray level. When two adjacent pixels are both required to be in the same gray level, the impulses applied to the two pixels are adjusted to that one pixel is below the desired gray level, while the other pixel is above the desired gray level. In a preferred form of this method, the pixels are divided into two groups, hereinafter designated “even” and “odd”. The two groups of pixels may be arranged in a checkerboard pattern (so that the pixels in each row and column alternate between the two groups) or in other arrangements as described above and in the aforementioned 2003/0137521, Paragraphs [0181] to [0183] and [0199] to [0202], provided that each pixel has at least one neighbor of the opposite group, and different drive schemes are used for the two groups. If the stored data indicates that one of the available impulses will produce substantially the desired gray level transition, this impulse is applied for that transition for both the even and odd pixels. However, if the stored data indicates that the impulse required for a particular gray level transition is substantially half-way between two of the available impulses, one of these impulses is used for the transition in even pixels and the other of these impulses is used for the transition in odd pixels. Thus, if two adjacent pixels are intended to be in the same gray state (the condition where precise control of gray scale is of maximum importance) one of these pixels will have a gray level slightly above the desired level, while the other will have a gray level slightly below the desired level. Ocular and optical averaging will result in an average of the two gray levels being seen, thus producing an apparent gray level closer to the desired level than can be achieved with the available impulses. In effect, this balanced gray level method uses small-signal spatial dithering (applied to correct errors in applied impulse) superimposed on large signal true gray scale to increase by a factor of two the available impulse levels. Since each pixel is still at approximately the correct gray scale level, the effective resolution of the display is not compromised. A complete implementation of the necessary calculations, in MATHLAB pseudo-code is given below. The floor function rounds down to the nearest integer, and the mod function computes the remainder of its first argument divided by its second argument: quotient=floor(desired_impuslse) remainder=mod(desired_impulse,1) if remainder<=0.25 even_parity_impulse=quotient odd_parity_impuslse=quotient else if remainder<=0.75 even_parity_impulse=quotient+1 odd_parity_impulse=quotient else even_parity_impulse=quotient+1 odd_parity_impulse=quotient+1 end. In some drive schemes previously described, for example the cyclic RSGS drive scheme described above with reference to FIGS. 11A and 11B, the pixels of the display are already divided into two groups and different drive schemes are applied to the two groups, so that the magnitude of the impulses needed to achieve the desired gray level will be different of the two groups. Such “two group” drive schemes can be modified in accordance with the balanced gray level method but the detailed implementation of the method differs somewhat from the simple case discussed above. Instead of simply comparing the available impulses with that required for the desired transition, one calculates the errors in gray scale for the two groups separately, takes the arithmetic average of the errors, and determines whether this arithmetic average would be reduced by shifting one of the groups to a different available impulse. Note that in this case, the reduction in arithmetic average may differ depending upon which group is shifted to a different impulse, and obviously whichever shift produces the smaller average should be effected. Again, this method can be thought of as small-signal spatial dithering implemented on top of large signal intrinsic gray scale, with the small signal dithering used to correct for errors in impulse due to the limitation of the pulse width modulation drive scheme used. Because each pixel is still approximately at the correct gray level in this scheme, and the corrections are only to correct for impulse rounding errors, effective display resolution is not compromised. To put it another way, this method implements small signal spatial dithering on top of large signal true gray scale. The various methods of the present invention may make use of various additional variations and techniques described in the aforementioned applications, especially the aforementioned 2003/0137521 and application Ser. No. 10/814,205, which variations and techniques are described in the “Additional Background Information” section below. It will be appreciated that in the overall waveform used to drive an electro-optic display, in at least some cases certain transitions may be effected in accordance with the various methods of the present invention, while other transitions may not make use of the methods of the present invention but may make use of other types of transitions described below. Additional Background Information Part A: Non-Contiguous Addressing As already briefly indicated, the present methods may make use of “non-contiguous addressing” as that term in used in the aforementioned application Ser. No. 10/814,205. As there described, such non-contiguous addressing has two principal variants, a DC imbalanced variant and a DC balanced variant. The DC imbalanced variant effects at least one transition between gray levels using an output signal which has a non-zero net impulse (i.e., the length of positive and negative segments is not equal), and therefore is not internally DC balanced, and is non-contiguous, (i.e. the pulse contains portions of zero voltage or opposite polarity). The output signal used in the non-contiguous addressing method may or may not be non-periodic (i.e., it may or may not consist of repeating units such as +/−/+/− or ++/−−/++/−−). Such a non-contiguous waveform (which may hereinafter be referred to as a “fine tuning” or “FT” waveform) may have no frames of opposite polarity, and/or may include only three voltage levels, +V, 0, and −V with respect to the effective front plane voltage of the display (assuming, as is typically the case, an active matrix display having a pixel electrode associated with each pixel and a common front electrode extending across multiple pixels, and typically the whole display, so the electric field applied to any pixel of the electro-optic medium is determined by the voltage difference between its associated pixel electrode and the common front electrode). Alternatively, an FT waveform may include more than three voltage levels. An FT waveform may consist of any one of the types of waveforms described above (such n-prepulse etc), with a non-contiguous waveform appended. An FT waveform may (and typically will) be dependent on one or more prior image states, and can be used in order to achieve a smaller change in optical state than can be achieved using standard pulse width modulation (PWM) techniques. (Thus, the exact FT waveform employed will vary from one transition to another in a look-up table, in contrast to certain prior art waveforms in which pulses of alternating polarity are employed, for example, allegedly to prevent sticking of electrophoretic particles to surfaces such as capsule walls.) In a preferred variant of the non-contiguous addressing method, there is provided a combination of all waveforms required to achieve all allowed optical transitions in a display (a “transition matrix”), in which at least one waveform is an FT waveform of the present invention and the combination of waveforms is DC-balanced. In another preferred variant of the non-contiguous addressing method, the lengths of all voltage segments are integer multiples of a single interval (the “frame time”); a voltage segment is a portion of a waveform in which the voltage remains constant. Non-contiguous addressing is based upon the discovery that, in many impulse driven electro-optic media, a waveform which has zero net impulse, and which thus might theoretically be expected to effect no overall change in the gray level of a pixel, can in fact, because of certain non-linear effects in the properties of such media, effect a small change in gray level, which can be used to achieve finer adjustment of gray levels than is possible using a simple PWM drive scheme or drivers with limited ability to vary the width and/or height of a pulse. The pulses which may up such a “fine tuning” waveform may be separate from the “major drive” pulses which effect a major change in gray level, and may precede or follow such major drive pulses. Alternatively, in some cases, the fine adjustment pulses may be intermingled with the major drive pulses, either a separate block of fine tuning pulses at a single point in the sequence of major drive pulses, or interspersed singly or in small groups at multiple points in the sequence of major drive pulses. Although non-contiguous addressing has very general applicability, it will primarily be described using as an example drive schemes using source drivers with three voltage outputs (positive, negative, and zero) and waveforms constructed from the following three types of waveform elements (since it is believed that the necessary modifications of the present invention for use with other types of drivers and waveform elements will readily be apparent to those skilled in the technology of electro-optic displays): 1) Saturation pulse: A sequence of frames with voltages of one sign or one sign and zero volts that drives the reflectance approximately to one extreme optical state (an optical rail, either the darkest state, here called the black state, or the brightest state, here called the white state); 2) Set pulse: A sequence of frames with voltages of one sign or one sign and zero volts that drives the reflectance approximately to a desired gray level (black, white or an intermediate gray level); and 3) FT sequence: A sequence of frames with voltages that are individually selected to be positive, negative, or zero, such that the optical state of the ink is moved much less than a single-signed sequence of the same length. Examples of FT drive sequences having a total length of five scan frames are: [+−+−−] (here, the voltage of each frame is represented sequentially by a + for positive voltage, 0 for zero voltage, and − for a negative voltage), [−−0++], [0 0 0 0 0], [0 0+−0], and [0−+0 0]. These sequences are shown schematically in FIGS. 21A-21E respectively of the accompanying drawings, in which the circles represent the starting and end points of the FT sequence, and there are five scan frames between these points. An FT sequence may be used either to allow fine control of the optical state, as previously described, or to produce a change in the optical state similar to that for a sequence of monopolar (single-signed) voltages but having a different net voltage impulse (where impulse is defined as the integral of the applied voltage over time). FT sequences in the waveform can thus be used as a tool to achieve DC balance. The use of an FT sequence to achieve fine control of the optical state will first be described. In FIG. 22, the optical states achievable using zero, one, two, three, or more frames of a monopolar voltage are indicated schematically as points on the reflectivity axis. From this Figure, it will be seen that the length of the monopolar pulse can be chosen to achieve a reflectance represented by its corresponding point on this axis. However, one may wish to achieve a gray level, such as that indicated by “target” in FIG. 22, that is not well approximated by any of these gray levels. An FT sequence can be used to fine-tune the reflectance to the desired state, either by fine tuning the final state achieved after a monopolar drive pulse, or by fine-tuning the initial state and then using a monopolar drive sequence. A first example of an FT sequence, shown in FIG. 23, shows an FT sequence being used after a two-pulse monopolar drive. The FT sequence is used to fine-tune the final optical state to the target state. Like FIG. 22, FIG. 23 shows the optical states achievable using various numbers of scan frames, as indicated by the solid points. The target optical state is also shown. The optical change by applying two scan frames is indicated, as is an optical shift induced by the FT sequence. A second example of an FT sequence is shown in FIG. 24; in this case, the FT sequence is used first to fine tune the optical state into a position where a monopolar drive sequence can be used to achieve the desired optical state. The optical states achievable after the FT sequence are shown by the open circles in FIG. 24. An FT sequence can also be used with a limited transitions waveform of the present invention, such as a rail-stabilized gray scale waveform, such as that described above with reference to FIGS. 11A and 11B. As mentioned above, the essence of a limited transitions waveform is that a given pixel is only allowed to make a limited number of gray-to-gray transitions before being driven to one of its extreme optical states. Thus, such waveforms use frequent drives into the extreme optical states (referred to as optical rails) to reduce optical errors while maintaining DC balance (where DC balance is a net voltage impulse of zero and is described in more detail below). Well resolved gray scale can be achieved using these waveforms by selecting fine-adjust voltages for one or more scan frames. However, if these fine-adjust voltages are not available, another method must be used to achieve fine tuning, preferably while maintaining DC balance as well. FT sequences may be used to achieve these goals. First, consider a cyclic version of a rail-stabilized grayscale waveform, in which each transition consists of zero, one, or two saturation pulses (pulses which drive the pixel into an optical rail) followed by a set pulse as described above (which takes the pixel to the desired gray level). To illustrate how FT sequences can be used in this waveform, a symbolic notation will be used for the waveform elements: “sat” to represent a saturation pulse; “set” to represent a set pulse; and “N” to represent an FT drive sequence. The three basic types of cyclic rail-stabilized grayscale waveforms are: set (for example, transition 1104 in FIG. 11A) sat-set (for example, transition 1106/1108 in FIG. 11A) sat-sat′-set (for example, transition 1116/1118/1120 in FIG. 11A) where sat and sat′ are two distinct saturation pulses. Modification of the first of these types with an FT sequence gives the following waveforms: N-set set-N that is, an FT sequence followed by a set pulse or the same elements in reverse order. Modification of the second of these types with one or more FT sequences gives, for example, the following FT-modified waveforms: N-sat-set sat-N-set sat-set-N sat-N-set-N′ N-sat-set-N′ N-sat-N′-set N-sat-N′-set-N″ where N, N′, and N″ are three FT sequences, which may or may not be different from one another. Modification of the second of these types can be achieved by interspersing FT sequences between the three waveform elements following essentially the previously described forms. An incomplete list of examples includes: N- sat-sat′-set N-sat-sat′-set-N′ sat-N-sat′-N′-set-N″ N-sat-N′-sat′-N″-set-N″. Another base waveform which can be modified with an FT sequence is the single-pulse slide show gray scale with drive to black (or white). In this waveform, the optical state is first brought to an optical rail, then to the desired image. The waveform of each transition can be symbolically represented by either of the two sequences: sat-set set. Such a waveform may be modified by inclusion of FT drive sequence elements in essentially the same manner as already described for the rail-stabilized gray scale sequence, to produce sequences such as: sat-set-N sat-N-set etc. The above two examples describe the insertion of FT sequences before or after saturation and set pulse elements of a waveform. It may be advantageous to insert FT sequences part way through a saturation or set pulse, that is the base sequence: sat-set would be modified to a form such as: {sat, part I}-N-{sat, part II}-set or sat-{set, part I}-N-{set, part II}. As already indicated, it has been discovered that the optical state of many electro-optic media achieved after a series of transitions is sensitive to the prior optical states and also to the time spent in those prior optical states, and methods have been described for compensating for prior state and prior dwell time sensitivities by adjusting the transition waveform accordingly. FT sequences can be used in a similar manner to compensate for prior optical states and/or prior dwell times. To describe this concept in more detail, consider a sequence of gray levels that are to be represented on a particular pixel; these levels are denoted R1, R2, R3, R4, and so on, where R1 denotes the next desired (final) gray level of the transition being considered, R2 is the initial gray level for that transition, R3 is the first prior gray level, R4 is the second prior gray level and so on. The gray level sequence can then be represented by: Rn Rn-1 Rn-2 . . . R3 R2 R1 The dwell time prior to gray level i is denoted Di. Di may represent the number of frame scans of dwell in gray level i. The FT sequences described above could be chosen to be appropriate for the transition from the current to the desired gray level. In the simplest form, these FT sequences are then functions of the current and desired gray level, as represented symbolically by: N=N(R2, R1) to indicate that the FT sequence N depends upon R2 and R1. To improve device performance, and specifically to reduce residual gray level shifts correlated to prior images, it is advantageous to make small adjustments to a transition waveform. Selection of FT sequences could be used to achieve these adjustments. Various FT sequences give rise to various final optical states. A different FT sequence may be chosen for different optical histories of a given pixel. For example, to compensate for the first prior image (R3), one could choose an FT sequence that depends on R3, as represented by: N=N(R3, R2, R1) That is, an FT sequence could be selected based not only on R1 and R2, but also on R3. Generalizing this concept, the FT sequence can be made dependent on an arbitrary number of prior gray levels and/or on an arbitrary number of prior dwell times, as represented symbolically by: N=N(Dm, Dm-1, . . . D3, D2; Rn, Rn-1, . . . R3, R2, R1) where the symbol Dk represents the dwell time spent in the gray level Rk and the number of optical states, n, need not equal the number of dwell times, m, required in the FT determination function. Thus FT sequences may be functions of prior images and/or prior and current gray level dwell times. As a special case of this general concept, it has been found that insertion of zero voltage scan frames into an otherwise monopolar pulse can change the final optical state achieved. For example, the optical state achieved after the sequence of FIG. 25, into which a zero voltage scan frame has been inserted, will differ somewhat from the optical state achieved after the corresponding monopolar sequence of FIG. 26, with no zero voltage scan frame but the same total impulse as the sequence of FIG. 25. It has also been found that the impact of a given pulse on the final optical state depends upon the length of delay between this pulse and a previous pulse. Thus, one can insert zero voltage frames between pulse elements to achieve fine tuning of a waveform. The present methods may extend to the use of FT drive elements and insertion of zero-volt scan frames in monopolar drive elements in other waveform structures. Other examples include but are not limited to double-prepulse (including triple-prepulse, quadruple-prepulse and so on) slide show gray scale waveforms, where both optical rails are visited (more than once in the case of higher numbers of prepulses) in going from one optical state to another, and other forms of rail-stabilized gray scale waveforms. FT sequences could also be used in general image flow gray scale waveforms, where direct transitions are made between gray level. While insertion of zero voltage frames can be thought of as a specific example of insertion of an FT sequence, where the FT sequence is all zeros, attention is directed to this special case because it has been found to be effective in modifying final optical states. The preceding discussion has focused on the use of FT sequences to achieve fine tuning of gray levels. The use of such FT sequences to achieve DC balance will now be considered. FT sequences can be used to change the degree of DC imbalance (preferably to reduce or eliminate DC imbalance) in a waveform. By DC balance is meant that all full-circuit gray level sequences (sequences that begin and end with the same gray level), have zero net voltage impulse. A waveform can be made DC balanced or less strongly DC imbalanced by use of one or more FT sequences, taking advantage of the fact that FT sequences can either (a) change the optical state in the same way as a saturation or set pulse but with a substantially different net voltage impulse; or (b) result in an insubstantial change in the optical state but with a net DC imbalance. The following illustration shows how FT sequences can be used to achieve DC balance. In this example, a set pulse can be of variable length, namely one, two, three or more scan frames. The final gray levels achieved for each of the number of scan frames are shown in FIG. 27, in which the number next to each point represents the number of scan frames used to achieve the gray level. FIG. 27 shows the optical states available using scan frames of positive voltage, monopolar drive where the number labels specify the number of monopolar frames used to produce the final gray level. Suppose that, in order to maintain DC balance in this example, a net voltage impulse of two positive voltage frames need to be applied. The desired (target) gray level could be achieved by using three scan frames of impulse; however, in doing so, the system would be left DC imbalanced by one frame. On the other hand, DC balance could be achieved by using two positive voltage scan frames instead of three, but the final optical state will deviate significantly from the target. One way to achieve DC balance is to use two positive voltage frames to drive the electro-optic medium to the vicinity of the desired gray level, and also use a DC balanced FT sequence (an FT sequence that has zero net voltage impulse) to make the final adjustment sufficiently close to the target gray level, as illustrated symbolically in FIG. 28, in which the target gray level is achieved using two scan frames followed by an FT sequence of zero net voltage impulse chosen to give the proper change in optical state. Alternatively, one could use three positive voltage scan frames of monopolar drive to bring the reflectance to the target optical state, then use an FT sequence that has a net DC imbalance equivalent to one negative voltage scan frame. If one chooses an FT sequence that results in a substantially unchanged optical state, then the final optical state will remain correct and DC-balance will be restored. This example is shown in FIG. 29. It will be appreciated that typically use of FT sequences will involve some adjustment of optical state along with some effect on DC balance, and that the above two examples illustrate extreme cases. The following Example is now given, though by way of illustration only, to show experimental uses of FT sequences in accordance with the present invention. EXAMPLE Use of FT sequences in cyclic RSGS waveform This Example illustrates the use of FT sequences in improving the optical performance of a waveform designed at achieve 4 gray level (2-bit) addressing of a single pixel display. This display used an encapsulated electrophoretic medium and was constructed substantially as described in Paragraphs [0069] to [0076] of the aforementioned 2002/0180687. The single-pixel display was monitored by a photodiode. Waveform voltages were applied to the pixel according to a transition matrix (look-up table), in order to achieve a sequence of gray levels within the 2-bit (4-state) grayscale. As already explained, a transition matrix or look-up table is simply a set of rules for applying voltages to the pixel in order to make a transition from one gray level to another within the gray scale. The waveform was subject to voltage and timing constraints. Only three voltage levels, −15V, 0V and +15V were applied across the pixel. Also, in order to simulate an active matrix drive with 50 Hz frame rate, voltages were applied in 20 ms increments. Tuning algorithms were employed iteratively in order to optimize the waveform, i.e. to achieve a condition where the spread in the actual optical state for each of the four gray levels across a test sequence was minimized. In an initial experiment, a cyclic rail-stabilized grayscale (cRSGS) waveform was optimized using simple saturation and set pulses. Consideration of prior states was limited to the initial (R2) and desired final (R1) gray levels in determining the transition matrix. The waveform was globally DC balanced. Because of the coarseness of the minimum impulse available for tuning (20 ms at 15 V), and the absence of states prior to R2 in the transition matrix, quite poor performance was anticipated from this waveform. The performance of the transition matrix was tested by switching the test pixel through a “pentad-complete” gray level sequence, which contained all gray level pentad sequences in a random arrangement. (Pentad sequence elements are sequences of five gray levels, such as 0-1-0-2-3 and 2-1-3-0-3, where 0, 1, 2 and 3 represent the four gray levels available.) For a perfect transition matrix, the reflectivity of each of the four gray levels is exactly the same for all occurrences of that gray level in the random sequence. The reflectivity of each of the gray levels will vary significantly for realistic transition matrices. The bar graph of FIG. 30 indeed shows the poor performance of the voltage and timing limited transition matrix. The measured reflectivity of the various occurrences of each of the target gray levels is highly variable. The cRSGS waveform optimized without FT sequences developed in this part of the experiment is hereinafter referred to as the base waveform. FT sequences were then incorporated into the cRSGS waveform; in this experiment, the FT sequences were limited to five scan frames, and included only DC balanced FT sequences. The FT sequences were placed at the end of the base waveform for each transition, i.e., the waveform for each transition had one of the following forms: set-N sat-set-N sat-sat′-set-N. Successful incorporation of FT sequence elements into the waveform required two steps; first, ascertaining the effect of various FT sequences on the optical state at each gray level and second selecting FT sequences to append to the various waveform elements. To ascertain the effect of various FT sequences on the optical state of each gray level, an “FT efficacy” experiment was performed. First, a consistent starting point was established by switching the electrophoretic medium repeatedly between black and white optical rails. Then, the film was taken to one of the four gray levels (0, 1, 2, or 3), here referred to as the optical state R2. Then, the base waveform appropriate to make the transition from R2 to one of the other gray levels (here called R1) with an appended FT sequence was applied. This step was repeated with all of the 51 DC balanced, 5-frame FT sequences. The final optical state was record for each of the FT sequences. The FT sequences were then ordered according to their associated final reflectivity. This process was repeated for all combinations of initial (R2) and final (R1) gray levels. The ordering of FT sequences for the final gray level 1 (R1=1) and the current gray level 0, 2 and 3 (R2=0, 2, 3) are shown in Tables 7-9, respectively, where the columns labeled “Frame 1” to “Frame 5” show the potential in volts applied during the five successive frames of the relevant FT sequence. The final optical states achieved for the waveform using the various FT sequences are plotted in FIG. 31. From this Figure, it will be seen that FT sequences can be used to affect a large change in the final optical state, and that the choices of five-scan-frame FT sequences afforded fine control over the final optical state, all with no net voltage impulse difference. TABLE 7 Final optical states for gray level 0 to 1 for various FT sequences. Index Optical Number (L*) Frame 1 Frame 2 Frame 3 Frame 4 Frame 5 1 35.13 0 15 15 −15 −15 2 35.20 15 0 15 −15 −15 3 35.22 15 15 0 −15 −15 4 35.48 15 15 −15 −15 0 5 35.65 15 15 −15 0 −15 6 36.07 0 15 −15 15 −15 7 36.10 15 −15 0 15 −15 8 36.23 15 0 −15 15 −15 9 36.26 15 −15 15 0 −15 10 36.32 15 −15 15 −15 0 11 36.34 −15 0 15 15 −15 12 36.36 −15 15 0 15 −15 13 36.37 0 0 15 0 −15 14 36.42 0 15 0 0 −15 15 36.47 0 0 0 15 −15 16 36.51 −15 15 15 0 −15 17 36.51 0 15 0 −15 0 18 36.55 0 0 15 −15 0 19 36.59 −15 15 15 −15 0 20 36.59 0 15 −15 0 0 21 36.59 0 −15 15 15 −15 22 36.68 15 0 0 0 −15 23 36.73 15 −15 −15 0 15 24 36.76 15 0 0 −15 0 25 36.79 15 0 −15 0 0 26 36.86 0 15 −15 −15 15 27 36.87 15 −15 0 0 0 28 37.00 15 0 −15 −15 15 29 37.03 −15 0 0 0 15 30 37.05 15 −15 −15 15 0 31 37.11 −15 0 0 15 0 32 37.19 15 −15 0 −15 15 33 37.19 −15 15 −15 0 15 34 37.22 0 −15 0 0 15 35 37.24 −15 0 15 0 0 36 37.26 −15 0 15 −15 15 37 37.33 0 −15 0 15 0 38 37.43 0 0 −15 0 15 39 37.43 −15 15 −15 15 0 40 37.49 −15 −15 15 0 15 41 37.50 −15 15 0 0 0 42 37.53 −15 15 0 −15 15 43 37.55 0 −15 15 −15 15 44 37.58 0 −15 15 0 0 45 37.61 0 0 −15 15 0 46 37.62 −15 −15 0 15 15 47 37.69 0 0 0 −15 15 48 37.72 0 0 0 0 0 49 37.85 −15 −15 15 15 0 50 37.96 −15 0 −15 15 15 51 37.99 0 −15 −15 15 15 TABLE 8 Final optical states for gray level 2 to 1 for various FT sequences. Index Optical Number (L*) Frame 1 Frame 2 Frame 3 Frame 4 Frame 5 1 34.85 0 15 15 −15 −15 2 34.91 15 0 15 −15 −15 3 35.07 15 15 −15 −15 0 4 35.15 15 15 0 −15 −15 5 35.35 15 15 −15 0 −15 6 35.43 0 15 −15 15 −15 7 35.46 15 −15 0 15 −15 8 35.51 0 0 15 −15 0 9 35.52 0 15 −15 0 0 10 35.52 0 0 0 15 −15 11 35.61 15 −15 15 −15 0 12 35.62 0 0 15 0 −15 13 35.63 15 −15 0 0 0 14 35.65 −15 15 0 15 −15 15 35.67 0 15 0 −15 0 16 35.70 −15 0 15 15 −15 17 35.75 15 −15 15 0 −15 18 35.76 0 15 0 0 −15 19 35.77 15 0 −15 0 0 20 35.78 15 0 −15 15 −15 21 35.80 −15 15 15 −15 0 22 35.97 −15 15 15 0 −15 23 35.98 15 0 0 −15 0 24 36.00 0 −15 15 15 −15 25 36.06 0 0 0 0 0 26 36.09 −15 0 0 15 0 27 36.10 −15 0 0 0 15 28 36.10 15 0 0 0 −15 29 36.14 −15 0 15 0 0 30 36.28 −15 15 0 0 0 31 36.38 15 −15 −15 0 15 32 36.40 0 15 −15 −15 15 33 36.41 0 −15 0 0 15 34 36.44 0 −15 0 15 0 35 36.45 15 −15 −15 15 0 36 36.49 −15 15 −15 0 15 37 36.49 0 −15 15 0 0 38 36.55 −15 0 15 −15 15 39 36.57 −15 15 −15 15 0 40 36.59 0 0 −15 0 15 41 36.63 0 0 −15 15 0 42 36.72 15 −15 0 −15 15 43 36.72 15 0 −15 −15 15 44 36.77 0 0 0 −15 15 45 36.81 −15 15 0 −15 15 46 36.89 0 −15 15 −15 15 47 36.98 −15 −15 15 0 15 48 37.16 −15 −15 15 15 0 49 37.19 −15 −15 0 15 15 50 37.42 −15 0 −15 15 15 51 37.51 0 −15 −15 15 15 TABLE 9 Final optical states for gray level 3 to 1 for various FT sequences. Index Optical Number (L*) Frame 1 Frame 2 Frame 3 Frame 4 Frame 5 1 36.86 0 15 15 −15 −15 2 36.92 15 0 15 −15 −15 3 37.00 15 15 −15 −15 0 4 37.13 15 15 0 −15 −15 5 37.39 15 15 −15 0 −15 6 37.47 0 15 −15 15 −15 7 37.48 15 −15 0 15 −15 8 37.50 0 15 −15 0 0 9 37.52 0 0 15 −15 0 10 37.53 0 0 0 15 −15 11 37.60 15 −15 15 −15 0 12 37.62 15 −15 0 0 0 13 37.63 0 0 15 0 −15 14 37.65 0 15 0 −15 0 15 37.67 −15 15 0 15 −15 16 37.71 −15 0 15 15 −15 17 37.76 0 15 0 0 −15 18 37.77 15 −15 15 0 −15 19 37.79 15 0 −15 15 −15 20 37.80 15 0 −15 0 0 21 37.82 −15 15 15 −15 0 22 37.96 15 0 0 −15 0 23 38.01 −15 15 15 0 −15 24 38.03 0 −15 15 15 −15 25 38.04 0 0 0 0 0 26 38.09 −15 0 0 15 0 27 38.09 15 0 0 0 −15 28 38.15 −15 0 0 0 15 29 38.16 −15 0 15 0 0 30 38.24 −15 15 0 0 0 31 38.40 15 −15 −15 0 15 32 38.43 0 −15 0 0 15 33 38.44 0 −15 0 15 0 34 38.44 0 15 −15 −15 15 35 38.46 15 −15 −15 15 0 36 38.51 −15 15 −15 0 15 37 38.52 0 −15 15 0 0 38 38.59 −15 0 15 −15 15 39 38.61 −15 15 −15 15 0 40 38.65 0 0 −15 0 15 41 38.66 0 0 −15 15 0 42 38.74 15 0 −15 −15 15 43 38.74 15 −15 0 −15 15 44 38.82 0 0 0 −15 15 45 38.89 −15 15 0 −15 15 46 38.95 0 −15 15 −15 15 47 39.02 −15 −15 15 0 15 48 39.21 −15 −15 15 15 0 49 39.22 −15 −15 0 15 15 50 39.44 −15 0 −15 15 15 51 39.53 0 −15 −15 15 15 Next, a cRSGS waveform was constructed using FT sequences chosen using the results represented in Tables 7 to 9 and FIG. 31 (specifically Sequence 33 from Table 7, Sequence 49 from Table 8 and Sequence 4 from Table 9), and their analogs for the other final gray levels. It is noted that the region between ˜36.9 and ˜37.5 L* on the y-axis in FIG. 31 shows the overlap between optical reflectance of the same final (R1) state with different initial (R2) states made available by using DC balanced FT sequences. Therefore, a target gray level for R1=1 was chosen at 37.2 L*, and the FT sequence for each R2 that gave the final optical state closest to this target was selected. This process was repeated for the other final optical states (R1=0, 2 and 3). Finally, the resultant waveform was tested using the pseudo-random sequence containing all five-deep state histories that was described earlier. This sequence contains 324 transitions of interest. The cRSGS waveform modified by the selected FT sequences was used to achieve all the transitions in this sequence, and the reflectivity of each of the optical states achieved was recorded. The optical states achieved are plotted in FIG. 32. It is apparent by comparing FIG. 32 with FIG. 30 that the spread in reflectivity of each of the gray levels was greatly reduced by incorporation of the FT sequences. In summary, non-contiguous addressing provides FT sequences which either (i) allow changes in the optical state or (ii) allow a means of achieving DC balance, or at least a change in the degree of DC imbalance, of a waveform. As already noted, it is possible to give a rather mathematical definition of an FT sequence, for example, for the DC imbalanced variant of the method: (a) Application of a DC imbalanced FT sequence that results in a change in optical state that is substantially different from the change in optical state of its DC reference pulse. The “DC reference pulse” is a pulse of voltage V0, where V0 is the voltage corresponding to the maximum voltage amplitude applied during the FT sequence but with the same sign as the net impulse of the FT sequence. The net impulse of a sequence is the area under the voltage versus time curve, and is denoted by the symbol G. The duration of the reference pulse is T=G/V0. This FT sequence is utilized to introduce a DC imbalance that differs significantly from the net DC imbalance of its reference pulse. (b) Application of a DC imbalanced FT sequence that results in a change in optical state that is much smaller in magnitude than the optical change one would achieve with its time reference pulse. The “time-reference pulse” is defined as a single-signed-voltage pulse of the same duration as the FT sequence, but where the sign of the reference pulse is chosen to give the largest change in optical state. That is, when the electro-optic medium is near its white state, a negative voltage pulse may drive the electro-optic medium only slightly more white, whereas a positive voltage may drive the electro-optic medium strongly toward black. The sign of the reference pulse in this case is positive. The goal of this type of FT pulse is to adjust the net voltage impulse (for DC balancing, for example) while not strongly affecting the optical state. Non-contiguous addressing also relates to the concept of using one or more FT sequences between or inserted into pulse elements of a transition waveform, and to the concept of using FT sequences to balance against the effect of prior gray levels and prior dwell times One specific example of the present invention is the use of zero voltage frames inserted in the middle of a pulse element of a waveform or in between pulse elements of a waveform to change the final optical state. Non-contiguous addressing also allows fine tuning of waveforms to achieve desired gray levels with desired precision, and a means by which a waveform can be brought closer to DC balanced (that is, zero net voltage impulse for any cyclic excursion to various gray levels), using source drivers that do not permit fine tuning of the voltage, especially source drivers with only two or three voltage levels. Part B: DC Balanced Addressing Method The sawtooth (cRSGS) drive scheme described above with reference to FIGS. 11A and 11B is well adapted for use in DC balancing, in that this drive scheme ensures that only a limited number of transitions can elapse between successive passes of any given pixel though the black state, and indeed that on average a pixel will pass through the black state on one-half of its transitions. However, DC balancing is not confined to balancing the aggregate of the impulses applied to the electro-optic medium during a succession of transitions, but also extends to making at least some of the transitions undergone by the pixels of the display “internally” DC balanced, as will now be described in detail. DC balanced transitions are advantageous for driving encapsulated electrophoretic and other impulse-driven electro-optic media for display applications. Such transitions can be applied, for example, to an active-matrix display that has source drivers that can output only two or three voltages. Although other types of drivers can be used, most of the detailed description below will focus on examples using source drivers with three voltage outputs (positive, negative, and zero). In the following description of a DC balanced addressing method, as in the preceding description of other aspects of the invention, the gray levels of an electro-optic medium will be denoted 1 to N, where 1 denotes the darkest state and N the lightest state. The intermediate states are numbered increasing from darker to lighter. A drive scheme for an impulse driven imaging medium makes use of a set of rules for achieving transitions from an initial gray level to a final gray level. The drive scheme can be expressed as a voltage as a function of time for each transition, as shown in Table 10 for each of the 16 possible transitions in a 2-bit (4 gray level) gray scale display. TABLE 10 final gray level 1 2 3 4 initial gray 1 V11(t) V12(t) V13(t) V14(t) level 2 V21(t) V22(t) V23(t) V24(t) 3 V31(t) V32(t) V33(t) V34(t) 4 V41(t) V42(t) V43(t) V44(t) In Table 10, Vij(t) denotes the waveform used to make the transition from gray level i to gray level j. DC-balanced transitions are ones where the time integral of the waveform Vij(t) is zero. The term “optical rails” has already been defined above as meaning the extreme optical states of an electro-optic medium. The phrase “pushing the medium towards or into an optical rail” will be employed below. By “towards”, is meant that a voltage is applied to move the optical state of the medium toward one of the optical rails. By “pushing”, is meant that the voltage pulse is of sufficient duration and amplitude that the optical state of the electro-optic medium is brought substantially close to one of the optical rails. It is important to note that “pushing into an optical rail” does not mean that the optical rail state is necessarily achieved at the end of the pulse, but that an optical state substantially close to the final optical state is achieved at the end of the pulse. For example, consider an electro-optic medium with optical rails at 1% and 50% reflectivities. A 300 msec pulse was found to bring the final optical state (from 1% reflectivity) to 50% reflectivity. One may speak of a 200 msec pulse as pushing the display into the high-reflectivity optical rail even though it achieves a final reflectivity of only 45% reflectance. This 200 msec pulse is thought of as pushing the medium into one of the optical rails because the 200 msec duration is long compared to the time required to traverse a large fraction of the optical range, such as the middle third of the optical range (in this case, 200 msec is long compared to the pulse required to bring the medium across the middle third of the reflectivity range, in this case, from 17% to 34% reflectance). Three different types of DC balanced transitions will now be described, together with a hybrid drive scheme using both DC balanced and DC imbalanced transitions. In the following description for convenience pulses will a denoted by a number, the magnitude of the number indicating the duration of the pulse. If the number is positive, the pulse is positive, and if the number is negative, the pulse is negative. Thus, for example, if the available voltages are +15V, 0V, and −15V, and the pulse duration is measured in milliseconds (msec), then a pulse characterized by x=300 indicates a 300 msec, 15V pulse, and x=−60 indicates a 60 msec, −15V pulse. Type I. In the first and simplest type of DC balanced transition, a voltage pulse (“x”) is preceded by a pulse (“−x”) of equal length but of opposite sign, as illustrated in FIG. 33. (Note that the value of x can itself be negative, so the positive and negative pulses may appear in the opposite order from that shown in FIG. 33.) As mentioned above, it has been found that the effect of the waveform used to effect a transition is modified by the presence of a period of zero voltage (in effect a time delay) during or before any of the pulses in the waveform, in accordance with the non-contiguous addressing method of the present invention. FIGS. 34 and 35 illustrate modifications of the waveform of FIG. 33. In FIG. 34, a time delay is inserted between the two pulses of FIG. 33 while in FIG. 35 the time delay in inserted within the second pulse of FIG. 33, or, which amounts to the same thing, the second pulse of FIG. 33 is split into two separate pulses separated by the time delay. As already described, time delays can be incorporated into a waveform to achieve optical states not achievable without such delays. Time delays can also be used to fine-tune the final optical state. This fine-tuning ability is important, because in an active matrix drive, the time resolution of each pulse is defined by the scan rate of the display. The time resolution offered by the scan rate can be coarse enough that precise final optical states cannot be achieved without some additional means of fine tuning. While time delays offer a small degree of fine tuning of the final optical state, additional features such as those described below offer additional means of coarse and fine tuning of the final optical state. Type II. A Type II waveform consists of a Type I waveform as described above with the insertion of a positive and negative pulse pair (denoted “+y” and “−y” pulses) at some point into the Type I waveform, as indicated symbolically in FIG. 36. The +y and −y pulses do not have to be consecutive, but can be present at different places into the original waveform. There are two especially advantageous forms of the Type II waveform. Type II: Special Case A: In this special form, the “−y,+y” pulse pair is placed before the “−x,+x” pulse pair. It has been found that, when y and x are of opposite sign, as illustrated in FIG. 37, the final optical state can be finely tuned by even moderately coarse adjustment of the duration y. Thus, the value of x can be adjusted for coarse control and the value of y for final control of the final optical state of the electro-optic medium. This is believed to happen because the y pulse augments the −x pulse, thus changing the degree to which the electro-optic medium is pushed into one of its optical rails. The degree of pushing into one of the optical rails is known to give fine adjustment of the final optical state after a pulse away from that optical rail (in this case, provided by the x pulse). Type II: Special Case B: For reasons indicated above, it has been found advantageous to use waveforms with at least one pulse element long enough to drive the electro-optic medium substantially into one optical rail. Also, for a more visually pleasing transition, it is desirable to arrive to the final optical state from the nearer optical rail, since achieving gray levels near an optical rail requires only a short final pulse. Waveforms of this type require at least one long pulse for driving into an optical rail and a short pulse to achieve the final optical state near that optical rail, and hence cannot have the Type I structure described above. However, special cases of the Type II waveform can achieve this type of waveform. FIG. 38 shows one example of such a waveform, where the +y pulse is placed after the −x,+x pulse pair and the −y pulse is placed before the −x,+x pulse pair. In this type of waveform, the final +y pulse provides coarse tuning because the final optical state is very sensitive to the magnitude of y. The +x pulse provides a finer tuning, since the final optical state typically does not depend as strongly on the magnitude of the drive into the optical rail. Type III. A third type (Type III) of DC balanced transition introduces yet another DC-balanced pulse pair (denoted “−z”, “+z”) into the waveform, as shown schematically in FIG. 39. A preferred example of such a Type III waveform is shown in FIG. 40; this type of waveform is useful for fine tuning of the final optical state, for the following reasons. Consider the situation without the +z and −z pulses (i.e. the Type II waveform discussed above). The x pulse element is used for fine tuning, and the final optical state can be decreased by increasing x and increased by decreasing x. However, it is undesirable to decrease x beyond a certain point because then the electro-optic medium is not brought sufficiently close to an optical rail, as required for stability of the waveform. To avoid this problem, instead of decreasing x, one can (in effect) increase the −x pulse without changing the x pulse by adding the −z,+z pulse pair as shown in FIG. 40, with z having the opposite sign from x. The z pulse augments the −x pulse, while the −z pulse maintains the transition at zero net impulse, i.e., maintains a DC-balanced transition. The Type I, II and III waveforms discussed above can of course be modified in various ways. Additional pairs of pulses can be added to the waveform to achieve more general structures. The advantage of such additional pairs diminishes with increasing number of pulse elements, but such waveforms are a natural extension of the Type I, II and III waveforms. Also, as already discussed, one or more time delays can be inserted in various places in any of the waveforms, in the same manner as illustrated in FIGS. 34 and 35. As mentioned earlier, time delays in pulses affect the final optical state achieved, and are thus useful for fine tuning. Also, the placement of time delays can change the visual appearance of transitions by changing the position of transition elements relative to other elements in the same transition as well as relative to transition elements of other transitions. Time delays can also be used to align certain waveform transition elements, and this may be advantageous for some display modules with certain controller capabilities. Also, in recognition of the fact that small changes in the ordering of the applied pulses may substantially change the optical state following the pulses, the output signal may also be formed by transposing all or part of one of the above-described pulse sequences, or by repeated transpositions of all or part of one of the above described sequences, or by the insertion of one or more 0 V periods at any location within one of the above-described sequences. In addition, these transposition and insertion operators can be combined in any order (e.g., insert 0 V section, then transpose, then insert 0 V section). It is important to note that all such pulse sequences formed by these transformations retain the essential character of having zero net impulse. Finally, DC balanced transitions can be combined with DC imbalanced transitions to form a complete drive scheme. For example, the −x/ΔIP/x waveform described above and illustrated in FIG. 12, while satisfactory for transitions between differing optical states, is less satisfactory for zero transitions in which the initial and final optical states are the same. For these zero transitions there is used, in this example, a Type II waveform such as the ones shown in FIGS. 37 and 38. This complete waveform is shown symbolically in Table 11, from which it will be seen that the −x/ΔIP/x waveform is used for non-zero transitions and the Type II waveform for zero transitions. TABLE 11 final gray level 1 2 3 4 initial gray 1 Type II −x/ΔIP/x −x/ΔIP/x −x/ΔIP/x level 2 −x/ΔIP/x Type II −x/ΔIP/x −x/ΔIP/x 3 −x/ΔIP/x −x/ΔIP/x Type II −x/ΔIP/x 4 −x/ΔIP/x −x/ΔIP/x −x/ΔIP/x Type II The use of DC balanced transitions is not of course confined to transition matrices of this type, in which DC balanced transitions are confined to the “leading diagonal” transitions, in which the initial and final gray levels are the same; to produce the maximum improvement in control of gray levels, it is generally desirable to maximize the number of transitions which are DC balanced. However, depending upon the specific electro-optic medium being used, it may be difficult to DC balance transitions involving transitions to or from extreme gray levels, for example to or from black and white, gray levels 1 and 4 respectively. Furthermore, in choosing which transitions are to be DC balanced, it is important not to imbalance the overall transition matrix, i.e., to produce a transition matrix in which a closed loop beginning and ending at the same gray level is DC imbalanced. For example, a rule that transitions involving only a change of 0 or 1 unit in gray level are DC balanced but other transitions are DC imbalanced is not desirable, since this would imbalance the entire transition matrix, as shown by the following example; a pixel undergoing the sequence of gray levels 2-4-3-2 would experience transitions 2-4 (DC imbalanced), 4-3 (balanced) and 3-2 (balanced), so that the entire loop would be imbalanced. A practical compromise between these two conflicting desires may be to use DC balanced transitions in cases where only mid gray levels (levels 2 and 3) are involved and DC imbalanced transitions where the transition begins or ends at an extreme gray level (level 1 or 4). Obviously, the mid gray levels chosen for such a rule may vary with the specific electro-optic medium and controller used; for example, in three-bit (8 gray level) display it might be possible to use DC balanced transitions in all transitions beginning or ending at gray levels 2-7 (or perhaps 3-6) and DC imbalanced transitions in all transitions beginning or ending at gray levels 1 and 8 (or 1, 2, 7 and 8). From the foregoing, it will be seen that the use of DC balanced transitions allows fine tuning of waveforms to achieve desired gray levels with high precision, and provides a means by which a waveform transition can have zero net voltage, using source drivers that do not permit fine tuning of the voltage, especially source drivers with only two or three voltage levels. It is believed that DC balanced waveform transitions offer better performance than DC imbalanced waveforms. This invention applies to displays in general, and especially, although not exclusively, to active-matrix display modules with source drivers that offer only two or three voltages. This invention also applies to active-matrix display modules with source drivers that offer more voltage levels. The use of DC balanced transitions can provide certain additional advantages. As noted above, in some driving methods of the invention, the transition matrix is a function of variables other than prior optical state, for example the length of time since the last update, or the temperature of the display medium. It is quite difficult to maintain DC balance in these cases with non-balanced transitions. For example, consider a display that repeatedly transitions from white to black at 25° C. and then from black to white at 0° C. The slower response at low temperature will typically dictate using a longer pulse length. As a result, the display will experience a net DC imbalance towards white. On the other hand, if all transitions are internally balanced, then different transition matrices can be freely mixed without introducing DC imbalance. Part C: Defined Region Method The objectionable effects of reset steps, as described above, may be further reduced by using local rather than global updating, i.e., by rewriting only those portions of the display which change between successive images, the portions to be rewritten being chosen on either a “local area” or a pixel-by-pixel basis. For example, it is not uncommon to find a series of images in which relatively small objects move across a larger static background, as for example in diagrams illustrating parts in mechanical devices or diagrams used in accident reconstruction. To use local updating, the display controller needs to compare the final image with the initial image and determine which area(s) differ between the two images and thus need to be rewritten. The controller may identify one or more local areas, typically rectangular areas having axes aligned with the pixel grid, which contain pixels which need to be updated, or may simply identify individual pixels which need to be updated. Any of the drive schemes already described may then be applied to update only the local areas or individual pixels thus identified as needing rewriting. Such a local updating scheme can substantially reduce the energy consumption of a display. Use of a “defined region” updating method of this type permits updating of a bistable electro-optic display using different updating methods in different regions of the display. Electro-optic displays are known in which the entire display can be driven in a one-bit or in a grayscale mode. When the display is in one-bit mode, updates are effected using a one-bit general image flow (GIF) waveform, whereas when the display is in grayscale mode, updates are effected using a multi-prepulse slide show waveform, or some other slow waveform, even if, in a specific area of the display, only one-bit information is being updated. Such an electro-optic display may be modified to carry out a defined region updating method by defining two additional commands in the controller, namely a “DEFINE REGION” command and a “CLEAR ALL REGIONS” command. The DEFINE REGION command typically takes as arguments locations sufficient to define completely a rectangular area of the display, for example the locations of the upper right and lower left comers of the defined region; this command may also have an additional argument specifying the bit depth to which the defined region is set, although this last argument is not necessary in simple forms of the defined region method in which the defined region is always monochrome. The bit depth set by the last argument of course overrides any bit depth previously set for the defined region. Alternatively, the DEFINE REGION command could specify a series of points defining the vertices of a polygon. The CLEAR ALL REGIONS command may take no arguments and simply reset the entire display to a single predefined bit depth, or might take a single argument specifying which of various possible bit depths is to be adopted by the entire display after the clearing operation. It will be appreciated that a defined region method is not restricted to the use of only two regions and more regions could be provided if desired. For example, in an image editing program it might be helpful to have a main region showing the image being edited at full bit depth, and both an information display region (for example, a box showing present cursor position) and a dialog box region (providing a dialog box for entry of text by the user) running in one-bit mode. The defined region method will primarily be described below in a two-region version, since the necessary modifications to enable use of more than two regions will readily be apparent to those skilled in the construction of display controllers. In order to keep track of the depths of the different regions, the controller may keep an array of storage elements, one element being associated with each pixel in the display, and each element storing a value representing the current bit depth for the associated pixel. For example, an SVGA (800×600) display capable of operating in either 1-bit or 2-bit mode could use an 800×600 array of 1-bit elements (each containing 0 for 1-bit mode, 1 for 2-bit mode). In such a controller, the DEFINE REGION command would set the elements within the defined region of the display to the requested bit depth, while the CLEAR ALL REGIONS command would reset all elements of the array to the same value (either a predetermined value or one defined by the argument of the command). Optionally, when a region is defined or cleared, the controller could execute an update sequence on the pixels within that region to transfer the display from one mode to the other, in order to ensure DC balancing or to adjust the optical states of the relevant pixels, for example by using an FT sequence as described above. When a display is operating in defined region mode, a new image is sent to the controller, and the display must be redrawn, there are three possible cases: 1. Only pixels within the defined (say) one-bit region have changed. In this case, a one-bit (fast) waveform can be used to update the display; 2. Only pixels within the non-defined (grayscale) regions have changed. In this case, a grayscale (slow) waveform must be used to update the display (note that since by definition not pixels are changed within the defined region, the legibility of the defined region, for example a dialog box, during the redrawing is not a problem); and 3. Pixels in both the defined and non-defined regions have changed. In this case, the grayscale pixels are updated using the grayscale waveform, and the one-bit pixels are updated using the one-bit waveform (the shorter one-bit waveforms must be zero-padded appropriately to match the length of the grayscale update). The controller may determine, before scanning thee display, which of these cases exists by performing the following logical tests (assuming a one-bit value associated with each pixel and storing the pixel mode, as defined above): (Old_image XOR new_image)>0: pixels are changed in the display (Old_image XOR new_image) AND mode_array>0: grayscale pixels are changed (Old_image XOR new_image) AND (NOT mode_array)>0: monochrome pixels are changed As the controller scans the display, for case 1 or case 2 it can use one waveform look-up table for all pixels, since the unchanged pixels will receive 0 V, assuming that a null transition in one-bit mode is the same as in grayscale mode (in other words, that both waveforms are local-update). If instead the grayscale waveform is global-update (all pixels are updated whenever the display is updated), then the controller will need to test to see if a pixel is within the appropriate region to determine whether to apply the global-update waveform or not. For Case 3, the controller must check the value of the mode bit array for each pixel as it scans to determine which waveform to use. Optionally, if the lightness values of the black and white states achieved in one-bit mode are identical to those achieved in grayscale mode, in Case 3 above the grayscale waveform can be used for all pixels in the display, thus eliminating the need for transfer functions between the one-bit and grayscale waveforms. The defined region method may make use of any of the optional features of the basic look-up table method, as described above. The primary advantage of the defined region method is that it enables the use of a fast one-bit waveform on a display that is displaying a previously written grayscale image. Prior art display controllers typically only allow the display to be in either grayscale or one-bit mode at any one time. While it is possible to write one-bit images in grayscale mode, the relevant waveforms are quite slow. In addition, the defined region method is essentially transparent to the host system (the system, typically a computer) which supplies images to the controller, since the host system does not have to advise the controller which waveform to use. Finally, the defined region method allows both one-bit and grayscale waveforms to be used on the display at the same time, whereas other solutions require two separate update events if both kinds of waveforms are being used. The aforementioned drive schemes may be varied in numerous ways depending upon the characteristics of the specific electro-optic display used. For example, in some cases it may be possible to eliminate many of the reset steps in the drives schemes described above. For example, if the electro-optic medium used is bistable for long periods (i.e., the gray levels of written pixels change only very slowly with time) and the impulse needed for a specific transition does not vary greatly with the period for which the pixel has been in its initial gray state, a look-up table may be arranged to effect gray state to gray state transitions directly without any intervening return to a black or white state, resetting of the display being effected only when, after a substantial period has elapsed, the gradual “drift” of pixels from their nominal gray levels has caused noticeable errors in the image presented. Thus, for example, if a user was using a display of the present invention as an electronic book reader, it might be possible to display numerous screens of information before resetting of the display were necessary; empirically, it has been found that with appropriate waveforms and drivers, as many as 1000 screens of information can be displayed before resetting is necessary, so that in practice resetting would not be necessary during a typical reading session of an electronic book reader. It will readily be apparent to those skilled in display technology that a single apparatus of the present invention could usefully be provided with a plurality of different drive schemes for use under differing conditions. For example, since in the drive schemes shown in FIGS. 9 and 10, the reset pulses consume a substantial fraction of the total energy consumption of the display, a controller might be provided with a first drive scheme which resets the display at frequent intervals, thus minimizing gray scale errors, and a second scheme which resets the display only at longer intervals, thus tolerating greater gray scale errors but reduce energy consumption. Switching between the two schemes can be effected either manually or dependent upon external parameters; for example, if the display were being used in a laptop computer, the first drive scheme could be used when the computer is running on mains electricity, while the second could be used while the computer was running on internal battery power. Part D: Compensation Voltage Method The methods of the present invention can be used in combination with a “compensation voltage” method and apparatus, which will now be described in detail. The compensation voltage method and apparatus seek to achieve results similar to the basic look-up table methods described above without the need to store very large look-up tables. The size of a look-up table grows rapidly with the number of prior states with regard to which the look-up table is indexed. For this reason, as already discussed, there is a practical limitation and cost consideration to increasing the number of prior states used in choosing an impulse for achieving a desired transition in a bistable electro-optic display. In the compensation voltage method and apparatus, the size of the look-up table needed is reduced, and compensation voltage data is stored for each pixel of the display, this compensation voltage data being calculated dependent upon at least one impulse previously applied to the relevant pixel. The voltage finally applied to the pixel is the sum of a drive voltage, chosen in the usual way from the look-up table, and a compensation voltage determined from the compensation voltage data for the relevant pixel. In effect, the compensation voltage data applies to the pixel a “correction” such as would otherwise be applied by indexing the look-up table for one or more additional prior states. The look-up table used in the compensation voltage method may be of any of the types described above. Thus, the look-up table may be a simple two-dimensional table which allows only for the initial and final states of the pixel during the relevant transition. Alternatively, the look-up table may take account of one or more temporal and/or gray level prior states. The compensation voltage may also take into account only the compensation voltage data stored for the relevant pixel but may optionally also take into account of one or more temporal and/or gray level prior states. The compensation voltage may be applied to the relevant pixel not only during the period for which the drive voltage is applied to the pixel but also during so-called “hold” states when no drive voltage is being applied to the pixel. The exact manner in which the compensation voltage data is determined may vary widely with the characteristics of the bistable electro-optic medium used. Typically, the compensation voltage data will periodically be modified in a manner which is determined by the drive voltage applied to the pixel during the present and/or one or more scan frames. In preferred forms of the invention, the compensation voltage data consists of a single numerical (register) value associated with each pixel of the display. In a preferred embodiment, scan frames are grouped into superframes in the manner already described so that a display update can be initiated only at the beginning of a superframe. A superframe may, for example, consist of ten display scan frames, so that for a display with a 50 Hz scan rate, a display scan is 20 ms long and a superframe 200 ms long. During each superframe while the display is being rewritten, the compensation voltage data associated with each pixel is updated. The updating consists of two parts in the following order: (1) Modifying the previous value using a fixed algorithm independent of the pulse applied during the relevant superframe; and (2) Increasing the value from step (1) by an amount determined by the impulse applied during the relevant superframe. In a particularly preferred embodiment, steps (1) and (2) are carried out as follows: (1) Dividing the previous value by a fixed constant, which is conveniently two; and (2) Increasing the value from step (1) by an amount proportional to the total area under the voltage/time curve applied to the electro-optic medium during the relevant superframe. In step (2), the increase may be exactly or only approximately proportional to the area under the voltage/time curve during the relevant superframe. For example, as described in detail below with reference to FIG. 41, the increase may be “quantized” to a finite set of classes for all possible applied waveforms, each class including all waveforms with a total area between two bounds, and the increase in step (2) determined by the class to which the applied waveform belongs. The following example is now given. The display used was a two-bit gray scale encapsulated electrophoretic display, and the drive method employed used a two-dimensional look-up table as shown in Table 12 below, which takes account only of the initial and final states of the desired transition; in this Table, the column headings represent the desired final state of the display and the row headings represent the initial state, while the numbers in individual cells represent the voltage in volts to be applied to the pixel for a predetermined period. TABLE 12 to: to: to: to: 0 1 2 3 from: 0 0 +6 +9 +15 from: 1 −6 0 +6 +9 from: 2 −9 −6 0 +6 from: 3 −15 −9 −6 0 To allow for practice of the compensation voltage method, a single numerical register was associated with each pixel of the display. The various impulses shown in Table 12 were classified and a pulse class was associated with each impulse, as shown in Table 13 below. TABLE 13 pulse voltage (V) −15 −9 −6 0 +6 +9 +15 pulse class −30 −18 −12 0 12 18 30 During each superframe, the numerical register associated with each pixel was divided by 2, and then increased by the numerical value shown in Table 13 for the pulse being applied to the relevant pixel during the same superframe. The voltage applied to each pixel during the superframe was the sum of the drive voltage, as shown in Table 12 and a compensation voltage, Vcomp, given by the formula: VComp=A*(pixel register) where the pixel register value is read from the register associated with the relevant pixel and “A” is a pre-defined constant. In a laboratory demonstration of this preferred compensation voltage method, single pixel displays using an encapsulated electrophoretic medium sandwiched between parallel electrodes, the front one of which was formed of ITO and light-transmissive, were driven by 300 millisecond +/−15V square wave pulses between their black and white states. The display started in its white state, was driven black, then back to white after a dwell time. It was found that the lightness of the final white state was a function of dwell time, as shown in FIG. 41 of the accompanying drawings. Thus, this encapsulated electrophoretic medium was sensitive to dwell time, with the L* of the white state varying by about 3 units depending upon dwell time. To show the effect of the compensation voltage method, the experiment was repeated, except that a compensation voltage, consisting of an exponentially decaying voltage starting at the end of each drive pulse, was appended to each pulse. The applied voltage was the sum of the drive voltage and the compensation voltage. As shown in FIG. 41, the white state for various dwell times in the case with the compensation voltage was much more uniform than for the uncompensated pulses. Thus, this experiment demonstrated that use of such compensation pulses in accordance with the present invention can greatly reduce the dwell time sensitivity of an encapsulated electrophoretic medium. The compensation voltage method of the present invention may make use of any of the optional features of the basic look-up table method described above. From the foregoing description, it will be seen that the present invention provides methods for controlling the operation of electro-optic displays which allow accurate control of gray scale without requiring inconvenient flashing of the whole display to one of its extreme states at frequent intervals. The present invention also allows for accurate control of the display despite changes in the temperature and operating time thereof, while lowering the power consumption of the display. These advantages can be achieved inexpensively, since the necessary controllers can be constructed from commercially available components. Part E: DTD Integral Reduction Method As mentioned above, it has been found that, at least in some cases, the impulse necessary for a given transition in a bistable electro-optic display varies with the residence time of a pixel in its optical state, this phenomenon, which does not appear to have previously been discussed in the literature, hereinafter being referred to as “dwell time dependence” or “DTD”. Thus, it may be desirable or even in some cases in practice necessary to vary the impulse applied for a given transition as a function of the residence time of the pixel in its initial optical state. The phenomenon of dwell time dependence will now be explained in more detail with reference to FIG. 42 of the accompanying drawings, which shows the reflectance of a pixel a function of time for a sequence of transitions denoted R3 →R2→R1, where each of the Rk terms indicates a gray level in a sequence of gray levels, with R's with larger indices occurring before R's with smaller indices. The transitions between R3 and R2 and between R2 and R1 are also indicated. DTD is the variation of the final optical state R1 caused by variation in the time spent in the optical state R2, referred to as the dwell time. The DTD integral reduction method provides a method for reducing dwell time dependence when driving bistable electro-optic displays. Although the invention is in no way limited by any theory as to its origin, DTD appears to be, in large part, caused by remnant electric fields experienced by the electro-optic medium. These remnant electric fields are residues of drive pulses applied to the medium. It is common practice to speak of remnant voltages resulting from applied pulses, and the remnant voltage is simply the scalar potential corresponding to remnant electric fields in the usual manner appropriate to electrostatic theory. These remnant voltages can cause the optical state of a display film to drift with time. They also can change the efficacy of a subsequent drive voltage, thus changing the final optical state achieved after that subsequent pulse. In this manner, the remnant voltage from one transition waveform can cause the final state after a subsequent waveform to be different from what it would be if the two transitions were very separate from each other. By “very separate” is meant sufficiently separated in time so that the remnant voltage from the first transition waveform has substantially decayed before the second transition waveform is applied. Measurements of remnant voltages resulting from transition waveforms and other simple pulses applied to an electro-optic medium indicate that the remnant voltage decays with time. The decay appears monotonic, but not simply exponential. However, as a first approximation, the decay can be approximated as exponential, with a decay time constant, in the case of most encapsulated electrophoretic media tested, of the order of one second, and other bistable electro-optic media are expected to display similar decay times. Accordingly, the DTD integral reduction method provides a method of driving a bistable electro-optic display having at least one pixel which comprises applying to the pixel a waveform V(t) such that: J = ∫ 0 T V ( t ) M ( T - t ) ⅆ t ( 1 ) (where T is the length of the waveform, the integral is over the duration of the waveform, V(t) is the waveform voltage as a function of time t, and M(t) is a memory function that characterizes the reduction in efficacy of the remnant voltage to induce dwell-time-dependence arising from a short pulse at time zero) is less than about 1 volt sec. Desirably J is less than about 0.5 volt sec., and most desirably less than about 0.1 volt sec. In fact J should be arranged to be as small as possible, ideally zero. Waveforms can be designed that give very low values of J and hence very small DTD, by generating compound pulses. For example, a long negative voltage pulse preceding a shorter positive voltage pulse (with a voltage amplitude of the same magnitude but of opposite sign) can result in a much-reduced DTD. It is believed that the two pulses provide remnant voltages with opposite signs. When the ratio of the lengths of the two pulses are correctly set, the remnant voltages from the two pulses can be caused to largely cancel each other. The proper ratio of the length of the two pulses can be determined by the memory function for the remnant voltage. In a presently preferred embodiment, J is calculated by: J = ∫ 0 T V ( t ) exp ( - T - t τ ) ⅆ t ( 2 ) where T is a decay (relaxation) time best determined empirically. For some encapsulated electrophoretic media, it has been found experimentally that waveforms that give rise to small J values also give rise to particularly low DTD, while waveforms with particularly large J values give rise to large DTD. In fact, good correlation has been found between J values calculated by Equation (2) above with T set to one second, roughly equal to the measured decay time of the remnant voltage after an applied voltage pulse. Thus, it is advantageous to use waveforms where each transition (or at least most of the transitions in the look-up table) from one gray level to another is achieved with a waveform that gives a small value of J. This J value is preferably zero, but empirically it has been found that, at least for the encapsulated electrophoretic media described in the aforementioned patents and application, as long as J had a magnitude less than about 1 volt sec. at ambient temperature, the resulting dwell time dependence is quite small. Thus, one can provide a waveform for achieving transitions between a set of optical states, where, for every transition, a calculated value for J has a small magnitude. The J is calculated by a memory function that is presumably monotonically decreasing. This memory function is not arbitrary but can be estimated by observing the dwell time dependence of the display film to simple voltage pulse or compound voltage pulses. As an example, one can apply a voltage pulse to the display film to achieve a transition from a first to a second optical state, wait a dwell time, then apply a second voltage pulse to achieve a transition from the second to a third voltage pulse. By monitoring the shift in the third optical state as a function of the dwell time, one can determine an approximate shape of the memory function. The memory function has a shape approximately similar to the difference in the third optical state from its value for long dwell times, as a function of the dwell time. The memory function would then be given this shape, and would have amplitude of unity when its argument is zero. This method yields only an approximation of the memory function, and for various final optical states, the measured shape of the memory function is expected to change somewhat. However, the gross features, such as the characteristic time of decay of the memory function, should be similar for various optical states. However, if there are significant differences in shape with final optical state, then the best memory function shape to adopt is one gained when the third optical state is in the middle third of the optical range of the display medium. The gross features of the memory function should also be estimable by measuring the decay of the remnant voltage after an applied voltage pulse. Although, the methods discussed here for estimating the memory function are not exact, it has been found that J values calculated from even an approximate memory are a good guide to waveforms having low DTD. A useful memory function expresses the gross features of the time dependence of the DTD as described above. For example, a memory function that is exponential with a decay time of one second has been found to work well in predicting waveforms that gave low DTD. Changing the decay time to 0.7 or 1.3 second does not destroy the effectiveness of the resulting J values as predictors of low DTD waveforms. However, a memory function that does not decay, but remains at unity indefinitely, is noticeably less useful as a predictor, and a memory function with a very short decay time, such as 0.05 second, was not a good predictor of low DTD waveforms. An example of a waveform that gives a small J value is the waveform shown in FIGS. 39 and 40 described above, where the x, y, and z pulses are all of durations much smaller than the characteristic decay time of the memory function. This waveform functions well when this condition is met because this waveform is composed of sequential opposing pulse elements whose remnant voltages tend to approximately cancel. For x and y values that are not much smaller than the characteristic decay time of the memory function but not larger than this decay time, it is found that that waveforms where x and y are of opposite sign tend to give lower J values, and x and y pulse durations can be found that actually permit very small J values because the various pulse elements give remnant voltages that cancel each other out after the waveform is applied, or at least largely cancel each other out. It will be appreciated that the J value of a given waveform can be manipulated by inserting periods of zero voltage into the waveform, or adjusting the lengths of any periods of zero voltage already present in the waveform. Thus a wide variety of waveforms can be used while still maintaining a J value close to zero. The DTD integral reduction method has general applicability. A waveform structure can be devised described by parameters, its J values calculated for various values of these parameters, and appropriate parameter values chosen to minimize the J value, thus reducing the DTD of the waveform. Part F: Remnant Voltage Method It has been found that the extent of DC imbalance in an electro-phoretic medium used in a display can be ascertained by measuring the open-circuit electrochemical potential (hereinafter for convenience called the “remnant voltage” of the medium. When the remnant voltage of a pixel is zero, it has been perfectly DC balanced. If its remnant voltage is positive, it has been DC unbalanced in the positive direction. If its remnant voltage is negative, it has been DC unbalanced in the negative direction. Remnant voltage data may be used to maintain long-term DC balancing of the display. In such a remnant voltage method, measurement of a remnant voltage is desirably effected by a high impedance voltage measurement device, for example a metal oxide semiconductor (MOS) comparator. When the display is one having small pixels, for example a 100 dots per inch (DPI) matrix display, in which each pixel has an area of 10−4 square inch or about 6×10−2 mm2, the comparator needs to have an ultra-low input current, as the resistance of such a single pixel is of the order of 1012 ohm. However, suitable comparators are readily available commercially; for example, the Texas Instruments INA111 chip is suitable, as it has an input current on only about 20 pA. (Technically, this integrated circuit is an instrumentation amplifier, but if its output is routed into a Schmitt trigger, it acts as a comparator.) For displays having large single pixels, such as large direct-drive displays (defined below) used in signage, where the individual pixels may have areas of several square centimeters, the requirements for the comparator are much less stringent, and almost any commercial FET input comparator may be used, for example the LF311 comparator from National Semiconductor Corporation. It will readily be apparent to those skilled in the art of electronic displays that, for cost and other reasons, mass-produced electronic displays will normally have drivers in the form of application specific integrated circuits (ASIC's), and in this type of display the comparator would typically be provided as part of the ASIC. Although this approach would require provision of feedback circuitry within the ASIC, it would have the advantage of making the power supply and oscillator sections of the ASIC simpler and smaller in area. If tri-level general image flow drive is required, this approach would also make the driver section of the ASIC simpler and smaller in area. Thus, this approach would typically reduce the cost of the ASIC. Conveniently, a driver which can apply a driving voltage, electronically short or float the pixel, is used to apply the driving pulses. When using such a driver, on each addressing cycle where DC balance correction is to be effected, the pixel is addressed, electronically shorted, then floated. (The term “addressing cycle” is used herein in its conventional meaning in the art of electro-optic displays to refer to the total cycle needed to change from a first to a second image on the display. As noted above, because of the relatively low switching speeds of electrophoretic displays, which are typically of the order of tens to hundreds of milliseconds, a single addressing cycle may comprise a plurality of scans of the entire display.) After a short delay time, the comparator is used to measure the remnant voltage across the pixel, and to determine whether it is positive or negative in sign. If the remnant voltage is positive, the controller may slightly extend the duration of (or slightly increase the voltage of) negative-going addressing pulses on the next addressing cycle. If, however, the remnant voltage is negative, the controller may slightly extend the duration of (or slightly increase the voltage of) positive-going voltage pulses on the next addressing cycle. Thus, the remnant voltage method places the electro-optic medium into a bang-bang feedback loop, adjusting the length of the addressing pulses to drive the remnant voltage toward zero. When the remnant voltage is near zero, the medium exhibits ideal performance and improved lifetime. In particular, use of the present invention may allow improved control of gray scale. As noted earlier, it has been observed that the gray scale level obtained in electro-optic displays is a function not only of the starting gray scale level and the impulse applied, but also of the previous states of the display. It is believed that one of the reasons for this “history” effect on gray scale level is that the remnant voltage affects the electric field experienced by the electro-optic medium; the actual electric field influencing the behavior of the medium is the sum of the voltage actually applied via the electrodes and the remnant voltage. Thus, controlling the remnant voltage ensures that the electric field experienced by the electro-optic medium accurately corresponds to that applied via the electrodes, thus permitting improved control of gray scale. The remnant voltage method is especially useful in displays of the so-called “direct drive” type, which are divided into a series of pixels each of which is provided with a separate electrode, the display further comprising switching means arranged to control independently the voltage applied to each separate electrode. Such direct drive displays are useful for the display of text or other limited character sets, for example numerical digits, and are described in, inter alia, the aforementioned International Application Publication No. 00/05704. However, the remnant voltage method can also be used with other types of displays, for example active matrix displays which use an array of transistors, at least one of which is associated with each pixel of the display. Activating the gate line of a thin film transistor (TFT) used in such an active matrix display connects the pixel electrode to the source electrode. The remnant voltage is small compared to the gate voltage (the absolute value of the remnant voltage typically does not exceed about 0.5 V), so the gate drive voltage will still turn the TFT on. The source line can then be electronically floated and connected to a MOS comparator, thus allowing reading the remnant voltage of each individual pixel of the active matrix display. It should be noted that, although the remnant voltage on a pixel of an electrophoretic display does closely correlate with the extent to which the current flow through that pixel has been DC balanced, zero remnant voltage does not necessarily imply perfect DC balance. However, from the practical point of view, this makes little difference, since it appears to be the remnant voltage itself rather than the DC balance history which is responsible for the adverse effects noted herein. It will readily be apparent to those skilled in the display art that, since the purpose of the remnant voltage method is to reduce remnant voltage and DC imbalance, this method need not be applied on every addressing cycle of a display, provided it is applied with sufficient frequency to prevent a long-term build-up of DC imbalance at a particular pixel. For example, if the display is one which requires use of a “refresh” or “blanking” pulse at intervals, such that during the refresh or blanking pulse all of the pixels are driven to the same display state, normally one of the extreme display states (or, more commonly, all of the pixels are first driven to one extreme display state, and then to the other extreme display state), the remnant voltage method might be practiced only during the refresh or blanking pulses. Although the remnant voltage method has primarily been described in its application to encapsulated electrophoretic displays, this method may be also be used with unencapsulated electrophoretic displays, and with other types of display, for example electrochromic displays, which display a remnant voltage. From the foregoing description, it will be seen that the remnant voltage method provides a method for driving electrophoretic and other electro-optic displays which reduces the cost of the equipment needed to ensure DC balancing of the pixels of the display, while providing increasing display lifetime, operating window and long-term display optical performance. As already indicated, a preferred type of electro-optic medium for use in present invention is an encapsulated particle-based electrophoretic medium. Such electrophoretic media used in the methods of the present invention may employ the same components and manufacturing techniques as in the aforementioned E Ink and MIT patents and applications, to which the reader is referred for further information. Numerous changes and modifications can be made in the preferred embodiments of the present invention already described without departing from the spirit and skill of the invention. Accordingly, the foregoing description is to be construed in an illustrative and not in a limitative sense.
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<SOH> BACKGROUND OF INVENTION <EOH>This invention relates to methods for driving electro-optic displays. The methods of the present invention are especially, though not exclusively, intended for use in driving bistable electrophoretic displays. The term “electro-optic” as applied to a material or a display, is used herein in its conventional meaning in the imaging art to refer to a material having first and second display states differing in at least one optical property, the material being changed from its first to its second display state by application of an electric field to the material. Although the optical property is typically color perceptible to the human eye, it may be another optical property, such as optical transmission, reflectance, luminescence or, in the case of displays intended for machine reading, pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range. The term “gray state” is used herein in its conventional meaning in the imaging art to refer to a state intermediate two extreme optical states of a pixel, and does not necessarily imply a black-white transition between these two extreme states. For example, several of the patents and published applications referred to below describe electrophoretic displays in which the extreme states are white and deep blue, so that an intermediate “gray state” would actually be pale blue. Indeed, as already mentioned the transition between the two extreme states may not be a color change at all. The terms “bistable” and “bistability” are used herein in their conventional meaning in the imaging art to refer to displays comprising display elements having first and second display states differing in at least one optical property, and such that after any given element has been driven, by means of an addressing pulse of finite duration, to assume either its first or second display state, after the addressing pulse has terminated, that state will persist for at least several times, for example at least four times, the minimum duration of the addressing pulse required to change the state of the display element. It is shown in published U.S. patent application No. 2002/0180687 that some particle-based electrophoretic displays capable of gray scale are stable not only in their extreme black and white states but also in their intermediate gray states, and the same is true of some other types of electro-optic displays. This type of display is properly called “multi-stable” rather than bistable, although for convenience the term “bistable” may be used herein to cover both bistable and multi-stable displays. The term “impulse” is used herein in its conventional meaning in the imaging art of the integral of voltage with respect to time. However, some bistable electro-optic media act as charge transducers, and with such media an alternative definition of impulse, namely the integral of current over time (which is equal to the total charge applied) may be used. The appropriate definition of impulse should be used, depending on whether the medium acts as a voltage-time impulse transducer or a charge impulse transducer. Several types of electro-optic displays are known. One type of electro-optic display is a rotating bichromal member type as described, for example, in U.S. Pat. Nos. 5,808,783; 5,777,782; 5,760,761; 6,054,071 6,055,091; 6,097,531; 6,128,124; 6,137,467; and 6,147,791 (although this type of display is often referred to as a “rotating bichromal ball” display, the term “rotating bichromal member” is preferred as more accurate since in some of the patents mentioned above the rotating members are not spherical). Such a display uses a large number of small bodies (typically spherical or cylindrical) which have two or more sections with differing optical characteristics, and an internal dipole. These bodies are suspended within liquid-filled vacuoles within a matrix, the vacuoles being filled with liquid so that the bodies are free to rotate. The appearance of the display is changed to applying an electric field thereto, thus rotating the bodies to various positions and varying which of the sections of the bodies is seen through a viewing surface. This type of electro-optic medium is typically bistable. Another type of electro-optic display uses an electrochromic medium, for example an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least in part from a semi-conducting metal oxide and a plurality of dye molecules capable of reversible color change attached to the electrode; see, for example O'Regan, B., et al., Nature 1991, 353, 737; and Wood, D., Information Display, 18(3), 24 (March 2002). See also Bach, U., et al., Adv. Mater., 2002, 14(11), 845. Nanochromic films of this type are also described, for example, in U.S. Pat. No. 6,301,038, International Application Publication No. WO 01/27690, and in U.S. patent application 2003/0214695. This type of medium is also typically bistable. Another type of electro-optic display, which has been the subject of intense research and development for a number of years, is the particle-based electrophoretic display, in which a plurality of charged particles move through a suspending fluid under the influence of an electric field. Electrophoretic displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption when compared with liquid crystal displays. Nevertheless, problems with the long-term image quality of these displays have prevented their widespread usage. For example, particles that make up electrophoretic displays tend to settle, resulting in inadequate service-life for these displays. Numerous patents and applications assigned to or in the names of the Massachusetts Institute of Technology (MIT) and E Ink Corporation have recently been published describing encapsulated electrophoretic media. Such encapsulated media comprise numerous small capsules, each of which itself comprises an internal phase containing electrophoretically-mobile particles suspended in a liquid suspending medium, and a capsule wall surrounding the internal phase. Typically, the capsules are themselves held within a polymeric binder to form a coherent layer positioned between two electrodes. Encapsulated media of this type are described, for example, in U.S. Pat. Nos. 5,930,026; 5,961,804; 6,017,584; 6,067,185; 6,118,426; 6,120,588; 6,120,839; 6,124,851; 6,130,773; 6,130,774; 6,172,798; 6,177,921; 6,232,950; 6,249,721; 6,252,564; 6,262,706; 6,262,833; 6,300,932; 6,312,304; 6,312,971; 6,323,989; 6,327,072; 6,376,828; 6,377,387; 6,392,785; 6,392,786; 6,413,790; 6,422,687; 6,445,374; 6,445,489; 6,459,418; 6,473,072; 6,480,182; 6,498,114; 6,504,524; 6,506,438; 6,512,354; 6,515,649; 6,518,949; 6,521,489; 6,531,997; 6,535,197; 6,538,801; 6,545,291; 6,580,545; 6,639,578; 6,652,075; 6,657,772; 6,664,944; 6,680,725; 6,683,333; 6,704,133; 6,710,540; 6,721,083; 6,724,519; and 6,727,881; and U.S. Patent Applications Publication Nos. 2002/0019081; 2002/0021270; 2002/0053900; 2002/0060321; 2002/0063661; 2002/0063677; 2002/0090980; 2002/0106847; 2002/0113770; 2002/0130832; 2002/0131147; 2002/0145792; 2002/0171910; 2002/0180687; 2002/0180688; 2002/0185378; 2003/0011560; 2003/0011868; 2003/0020844; 2003/0025855; 2003/0034949; 2003/0038755; 2003/0053189; 2003/0102858; 2003/0132908; 2003/0137521; 2003/0137717; 2003/0151702; 2003/0189749; 2003/0214695; 2003/0214697; 2003/0222315; 2004/0008398; 2004/0012839; 2004/0014265; 2004/0027327; 2004/0075634; and 2004/0094422; and International Applications Publication Nos. WO 99/67678; WO 00/05704; WO 00/38000; WO 00/38001; WO00/36560; WO 00/67110; WO 00/67327; WO 01/07961; WO 01/08241; WO 03/092077; WO 03/107315; WO 2004/017035; and WO 2004/023202. Many of the aforementioned patents and applications recognize that the walls surrounding the discrete microcapsules in an encapsulated electrophoretic medium could be replaced by a continuous phase, thus producing a so-called “polymer-dispersed electrophoretic display” in which the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be regarded as capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet; see for example, the aforementioned 2002/0131147. Accordingly, for purposes of the present application, such polymer-dispersed electrophoretic media are regarded as sub-species of encapsulated electrophoretic media. An encapsulated electrophoretic display typically does not suffer from the clustering and settling failure mode of traditional electrophoretic devices and provides further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates. (Use of the word “printing” is intended to include all forms of printing and coating, including, but without limitation: pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; ink jet printing processes; and other similar techniques.) Thus, the resulting display can be flexible. Further, because the display medium can be printed (using a variety of methods), the display itself can be made inexpensively. A related type of electrophoretic display is a so-called “microcell electrophoretic display”. In a microcell electrophoretic display, the charged particles and the suspending fluid are not encapsulated within capsules but instead are retained within a plurality of cavities formed within a carrier medium, typically a polymeric film. See, for example, International Application Publication No. WO 02/01281, and U.S. Patent Application Publication No. 2002/0075556, both assigned to Sipix Imaging, Inc. Although electrophoretic media are often opaque (since, for example, in many electrophoretic media, the particles substantially block transmission of visible light through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in a so-called “shutter mode” in which one display state is substantially opaque and one is light-transmissive. See, for example, the aforementioned U.S. Pat. Nos. 6,130,774 and 6,172,798, and U.S. Pat. Nos. 5,872,552; 6,144,361; 6,271,823; 6,225,971; and 6,184,856. Dielectrophoretic displays, which are similar to electrophoretic displays but rely upon variations in electric field strength, can operate in a similar mode; see U.S. Pat. No. 4,418,346. Other types of electro-optic displays may also be capable of operating in shutter mode. The bistable or multi-stable behavior of particle-based electrophoretic displays, and other electro-optic displays displaying similar behavior (such displays may hereinafter for convenience be referred to as “impulse driven displays”), is in marked contrast to that of conventional liquid crystal (“LC”) displays. Twisted nematic liquid crystals act are not bi- or multi-stable but act as voltage transducers, so that applying a given electric field to a pixel of such a display produces a specific gray level at the pixel, regardless of the gray level previously present at the pixel. Furthermore, LC displays are only driven in one direction (from non-transmissive or “dark” to transmissive or “light”), the reverse transition from a lighter state to a darker one being effected by reducing or eliminating the electric field. Finally, the gray level of a pixel of an LC display is not sensitive to the polarity of the electric field, only to its magnitude, and indeed for technical reasons commercial LC displays usually reverse the polarity of the driving field at frequent intervals. In contrast, bistable electro-optic displays act, to a first approximation, as impulse transducers, so that the final state of a pixel depends not only upon the electric field applied and the time for which this field is applied, but also upon the state of the pixel prior to the application of the electric field. Whether or not the electro-optic medium used is bistable, to obtain a high-resolution display, individual pixels of a display must be addressable without interference from adjacent pixels. One way to achieve this objective is to provide an array of non-linear elements, such as transistors or diodes, with at least one non-linear element associated with each pixel, to produce an “active matrix” display. An addressing or pixel electrode, which addresses one pixel, is connected to an appropriate voltage source through the associated non-linear element. Typically, when the non-linear element is a transistor, the pixel electrode is connected to the drain of the transistor, and this arrangement will be assumed in the following description, although it is essentially arbitrary and the pixel electrode could be connected to the source of the transistor. Conventionally, in high resolution arrays, the pixels are arranged in a two-dimensional array of rows and columns, such that any specific pixel is uniquely defined by the intersection of one specified row and one specified column. The sources of all the transistors in each column are connected to a single column electrode, while the gates of all the transistors in each row are connected to a single row electrode; again the assignment of sources to rows and gates to columns is conventional but essentially arbitrary, and could be reversed if desired. The row electrodes are connected to a row driver, which essentially ensures that at any given moment only one row is selected, i.e., that there is applied to the selected row electrode a voltage such as to ensure that all the transistors in the selected row are conductive, while there is applied to all other rows a voltage such as to ensure that all the transistors in these non-selected rows remain non-conductive. The column electrodes are connected to column drivers, which place upon the various column electrodes voltages selected to drive the pixels in the selected row to their desired optical states. (The aforementioned voltages are relative to a common front electrode which is conventionally provided on the opposed side of the electro-optic medium from the non-linear array and extends across the whole display.) After a pre-selected interval known as the “line address time” the selected row is deselected, the next row is selected, and the voltages on the column drivers are changed to that the next line of the display is written. This process is repeated so that the entire display is written in a row-by-row manner. It might at first appear that the ideal method for addressing such an impulse-driven electro-optic display would be so-called “general grayscale image flow” in which a controller arranges each writing of an image so that each pixel transitions directly from its initial gray level to its final gray level. However, inevitably there is some error in writing images on an impulse-driven display. Some such errors encountered in practice include: (a) Prior State Dependence; With at least some electro-optic media, the impulse required to switch a pixel to a new optical state depends not only on the current and desired optical state, but also on the previous optical states of the pixel. (b) Dwell Time Dependence; With at least some electro-optic media, the impulse required to switch a pixel to a new optical state depends on the time that the pixel has spent in its various optical states. The precise nature of this dependence is not well understood, but in general, more impulse is required that longer the pixel has been in its current optical state. (c) Temperature Dependence; The impulse required to switch a pixel to a new optical state depends heavily on temperature. (d) Humidity Dependence; The impulse required to switch a pixel to a new optical state depends, with at least some types of electro-optic media, on the ambient humidity. (e) Mechanical Uniformity; The impulse required to switch a pixel to a new optical state may be affected by mechanical variations in the display, for example variations in the thickness of an electro-optic medium or an associated lamination adhesive. Other types of mechanical non-uniformity may arise from inevitable variations between different manufacturing batches of medium, manufacturing tolerances and materials variations. (f) Voltage Errors; The actual impulse applied to a pixel will inevitably differ slightly from that theoretically applied because of unavoidable slight errors in the voltages delivered by drivers. General grayscale image flow suffers from an “accumulation of errors” phenomenon. For example, imagine that temperature dependence results in a 0.2 L* (where L* has the usual CIE definition: in-line-formulae description="In-line Formulae" end="lead"? L* =116( R/R 0 ) 1/3 −16 in-line-formulae description="In-line Formulae" end="tail"? where R is the reflectance and R 0 is a standard reflectance value) error in the positive direction on each transition. After fifty transitions, this error will accumulate to 10 L*. Perhaps more realistically, suppose that the average error on each transition, expressed in terms of the difference between the theoretical and the actual reflectance of the display is ±0.2 L*. After 100 successive transitions, the pixels will display an average deviation from their expected state of 2 L*; such deviations are apparent to the average observer on certain types of images. This accumulation of errors phenomenon applies not only to errors due to temperature, but also to errors of all the types listed above. As described in the aforementioned 2003/0137521, compensating for such errors is possible, but only to a limited degree of precision. For example, temperature errors can be compensated by using a temperature sensor and a lookup table, but the temperature sensor has a limited resolution and may read a temperature slightly different from that of the electro-optic medium. Similarly, prior state dependence can be compensated by storing the prior states and using a multi-dimensional transition matrix, but controller memory limits the number of states that can be recorded and the size of the transition matrix that can be stored, placing a limit on the precision of this type of compensation. Thus, general grayscale image flow requires very precise control of applied impulse to give good results, and empirically it has been found that, in the present state of the technology of electro-optic displays, general grayscale image flow is infeasible in a commercial display. Almost all electro-optic medium have a built-in resetting (error limiting) mechanism, namely their extreme (typically black and white) optical states, which function as “optical rails”. After a specific impulse has been applied to a pixel of an electro-optic display, that pixel cannot get any whiter (or blacker). For example, in an encapsulated electrophoretic display, after a specific impulse has been applied, all the electrophoretic particles are forced against one another or against the capsule wall, and cannot move further, thus producing a limiting optical state or optical rail. Because there is a distribution of electrophoretic particle sizes and charges in such a medium, some particles hit the rails before others, creating a “soft rails” phenomenon, whereby the impulse precision required is reduced when the final optical state of a transition approaches the extreme black and white states, whereas the optical precision required increases dramatically in transitions ending near the middle of the optical range of the pixel. Various types of drive schemes for electro-optic displays are known which take advantage of optical rails. For example, FIGS. 9 and 10 of the aforementioned 2003/0137521 (reproduced below), and the related description at Paragraphs [0177] to [0180], describe a “slide show” drive scheme in which the entire display is driven to both optical rails before any new image is written. Such a slide show drive scheme produces accurate grayscale levels, but the flashing of the display as it is driven to the optical rails is distracting to the viewer. It has also been suggested (see the aforementioned U.S. Pat. No. 6,531,997) that a similar drive scheme be employed in which only the pixels, whose optical states need to be changed in the new image, be driven to the optical rails. However, this type of “limited slide show” drive scheme is, if anything, even more distracting to the viewer, since the solid flashing of a normal slide show drive scheme is replaced by image dependent flashing, in which features of the old image and the new image flash in reverse color on the screen before the new image is written. Obviously, a pure general grayscale image flow drive scheme cannot rely upon using the optical rails to prevent errors in gray levels since in such a drive scheme any given pixel can undergo an infinitely large number of changes in gray level without ever touching either optical rail. In one aspect, this invention seeks to provide methods for achieving control of gray levels in electro-optic displays which achieve stability of gray levels similar to those achieved by slide show drive schemes but which do not suffer from the distracting flashing of slide show drive schemes. Preferred methods of the present invention can give the viewer a visual experience similar to that provided by a pure general grayscale image flow drive scheme. In another aspect, this invention seeks to provide methods for achieving fine control of gray levels in displays driven by pulse width modulation. When driving an active matrix display having a bistable electro-optic medium to write gray scale images thereon, it is desirable to be able to apply a precise amount of impulse to each pixel, so as to achieve accurate control of the gray scale displayed. The driving method used may rely modulation of the voltage applied to each pixel and/or modulation of the “width” (duration) for which the voltage is applied. Since voltage modulated drivers and their associated power supplies are relatively costly, pulse width modulation is commercially attractive. However, during the scanning of an active matrix display using such pulse width modulation, conventional driver circuitry only allows one to apply a single voltage to any given pixel during any one scan of the matrix. Consequently, pulse width modulation driving of active matrix displays is effected by scanning the matrix multiple times, with the drive voltage being applied during none, some or all of the scans, depending upon the change desired in the gray level of the specific pixel. Each scan may be regarded as a frame of the drive waveform, with the complete addressing pulse being a superframe formed by a plurality of successive frames. It should be noted that, although the drive voltage is only applied to any specific pixel electrode for one line address time during each scan, the drive voltage persists on the pixel electrodes during the time between successive selections of the same line, only slowly decaying, so that the pixel is driven between successive selections of the same line. As already mentioned, each row of the matrix needs to be individually selected during each frame so that for high resolution displays (for example, 800×600 pixel displays) in practice the frame rate cannot exceed about 50 to 100 Hz; thus each frame typically lasts 10 to 20 ms. Frames of this length lead to difficulties in fine control of gray scale with many fast switching electro-optic medium. For example, some encapsulated electrophoretic media substantially complete a switch between their extreme optical states (a transition of about 30 L* units) within about 100 ms, and with such a medium a 20 ms frame corresponds to a gray scale shift of about 6 L* units. Such a shift is too large for accurate control of gray scale; the human eye is sensitive to differences in gray levels of about 1 L* unit, and controlling the impulse only in graduations equivalent to about 6 L* units is likely to give rise to visible artifacts, such as “ghosting” due to prior state dependence of the electro-optic medium, and pulses needed to ensure that the waveform used is DC balanced (see the applications mentioned in the “Cross Reference to Related Applications” section above). More specifically, ghosting may be experienced because, as discussed in some of the aforementioned patents and applications, the variation of gray level with applied impulse is not linear, and the total impulse needed for any specific change in gray level may vary with the time at which the impulse is applied and the intervening gray levels. For example, in a simple 4 gray level (2 bit) display having gray levels 0 (black), 1 (dark gray), 2 (light gray) and 3 (white), driven by a simple pulse width modulation drive scheme, these non-linearities may result in the actual gray level achieved after a notional 0-2 transition being different from the gray level achieved after a notional 1-2 transition, with the production of highly undesirable visual artifacts. This invention provides methods for achieving fine control of gray levels in displays driven by pulse width modulation, thus avoiding the aforementioned problems.
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<SOH> SUMMARY OF INVENTION <EOH>Accordingly, in one aspect, this invention provides a method for driving an electro-optic display having at least one pixel capable of achieving any one of at least four different gray levels including two extreme optical states. The method comprises: displaying a first image on the display; and rewriting the display to display a second image thereon, wherein, during the rewriting of the display any pixel which has undergone a number of transitions exceeding a predetermined value, the predetermined value being at least one, without touching an extreme optical state, is driven to at least one extreme optical state before driving that pixel to its final optical state in the second image. This method may hereinafter for convenience be referred to as the “limited transitions method” of the present invention. In one form of this limited transitions method, the rewriting of the display is effected such that, once a pixel has been driven from one extreme optical state towards the opposed extreme optical state by a pulse of one polarity, the pixel does not receive a pulse of the opposed polarity until it has reached the opposed extreme optical state. Also, in the limited transitions methods, the predetermined value (predetermined number of transitions) is not greater than N/2, where N is the total number of gray levels capable of being displayed by a pixel. The limited transitions method may be effected using a tri-level driver, i.e., the rewriting of the display may be effected by applying to the or each pixel any one or more of voltages −V, 0 and +V. The limited transitions method may also be DC-balanced, i.e., the rewriting of the display may be effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded. In the limited transitions method of the present invention, the rewriting of the display may be effected such that the impulse applied to a pixel during a transition depends only upon the initial and final gray levels of that transition. Alternatively, the method may be adapted to take account of other states of the display, as described in more detail below. In one preferred form of the limited transitions method, for at least one transition undergone by the at least one pixel from a gray level R 2 to a gray level R 1 , there is applied to the pixel a sequence of impulses of the form: in-line-formulae description="In-line Formulae" end="lead"? −TM(R 1 ,R 2 ) IP(R 1 )−IP(R 2 ) TM(R 1 ,R 2 ) in-line-formulae description="In-line Formulae" end="tail"? where “IP(Rx)” represents the relevant value from an impulse potential matrix having one value for each gray level, and TM(R 1 ,R 2 ) represents the relevant value from a transition matrix having one value for each R 1 /R 2 combination. (For convenience, impulse sequences of this type may hereinafter be abbreviated as “−x/ΔIP/x” sequences.) Such −x/ΔIP/x sequences may be used for all transitions in which the initial and final gray levels are different. Also, in such −x/ΔIP/x sequences, the final “x” section may occupy more than one half of the maximum update time. The TM(R 1 ,R 2 ) or x values may be chosen such that the sign of each value is dependent only upon R 1 ; in particular, these values may be chosen to be positive for one or more light gray levels and negative for one or more dark gray levels so that gray levels other than the two extreme optical states are approached from the direction of the nearer extreme optical state. The aforementioned −x/ΔIP/x sequences may contain additional pulses. In particular, such sequences may comprise an additional pair of pulses of the form [+y][−y], where y is an impulse value, which may be either negative or positive, the [+y] and [−y] pulses being inserted into the −x/ΔIP/x sequence. The sequence may further comprise a second additional pair of pulses of the form [+z][−z], where z is an impulse value different from y and may be either negative or positive, the [+z] and [−z] pulses being inserted into the −x/ΔIP/x sequence. The −x/ΔIP/x sequences may further comprise a period when no voltage is applied to the pixel. This “no voltage” period may occur between two elements of the −x/ΔIP/x sequence, or within a single element thereof. The −x/ΔIP/x sequences may include two or more “no voltage” periods. When using the aforementioned −x/ΔIP/x sequences, the display may comprise a plurality of pixels divided into a plurality of groups, and the transition may be effected by (a) selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period; (b) repeating the scanning of the groups of pixels during a second frame period; and (c) interrupting the scanning of the groups of pixels during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. In the limited transitions method, the rewriting of the display may be effected such that a transition to a given gray level is always effected by a final pulse of the same polarity. In particular, gray levels other than the two extreme optical states may be approached from the direction of the nearer extreme optical state. This invention also provides a method for driving an electro-optic display having a plurality of pixels divided into a plurality of groups. This method comprises: (a) selecting each of the plurality of groups of pixels in succession and applying to each of the pixels in the selected group either a drive voltage or a non-drive voltage, the scanning of all the groups of pixels being completed in a first frame period; (b) repeating the scanning of the groups of pixels during a second frame period; and (c) interrupting the scanning of the groups of pixels during a pause period between the first and second frame periods, this pause period being not longer than the first or second frame period. This method may hereinafter for convenience be referred to as the “interrupted scanning” method of the present invention. In such an interrupted scanning method, typically the first and second frame periods are equal in length. The length of the pause period may be a sub-multiple of the length of one of the first and second frame periods. The interrupted scanning method may include multiple pause periods; thus the method may comprise scanning the groups of pixels during at least first, second and third frame periods, and interrupting the scanning of the groups of pixels during at least first and second pause periods between successive frame periods. The first, second and third frame periods may be substantially equal in length, and the total length of the pause periods be equal to one frame period or one frame period minus one pause period. Typically, in the interrupted scanning method, the pixels are arranged in a matrix having a plurality of rows and a plurality of columns with each pixel defined by the intersection of a given row and a given column, and each group of pixels comprises one row or one column of the matrix. The interrupted scanning method is preferably DC balanced, i.e., the scanning of the display is preferably effected such that, for any series of transitions undergone by a pixel, the integral of the applied voltage with time is bounded. In another aspect, this invention provides a method for driving an electro-optic display having a plurality of pixels, the pixels being driven with a pulse width modulated waveform capable of applying a plurality of differing impulses to each pixel. This method comprises: (a) storing data indicating whether application of a given impulse to a pixel will produce a gray level higher or lower than a desired gray level; (b) detecting when two adjacent pixels are both required to be in the same gray level; and (c) adjusting the impulses applied to the two pixels so that one pixel is below the desired gray level, while the other pixel is above the desired gray level. This method may hereinafter for convenience be referred to as the “balanced gray level” method of the present invention. In this method, the pixels may be divided into two groups such that each pixel has at least one neighbor of the opposite group, and different drive schemes be used for the two groups. Each the methods of the present invention as described above may be carried out with any of the aforementioned types of electro-optic media. Thus, the methods of the present invention may be used with electro-optic displays comprising an electrochromic or rotating bichromal member electro-optic medium, an encapsulated electrophoretic medium, or a microcell electrophoretic medium. Other types of electro-optic media may also be employed.
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20040629
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20090505
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20050203
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96705.0
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SHERMAN, STEPHEN G
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METHODS FOR DRIVING ELECTRO-OPTIC DISPLAYS
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UNDISCOUNTED
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CONT-ACCEPTED
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10,879,586
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ACCEPTED
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System and method for transferring data in high latency firewalled networks
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A system and method are provided for establishing multiple parallel connections between a client and a server on a single server port. Data may be transferred on the multiple parallel connections between the server and the client through an opening in a network firewall that corresponds to the single server port. A control process may accept N connection requests from a client then transfer each accepted connection to a relay process that manages that connection. Each relay process may relay data between the server and the client via the single server port. A single collective data transfer may be executed on the N parallel connections, thereby increasing throughput and data transfer rates. If the data transfer rate is primarily limited by network latency, using N parallel connections provides the advantage of increasing the data transfer rate by approximately a factor of N.
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1. A method of increasing data transfer rates in a network including a firewall, the method comprising: receiving a connection request from a client for a plurality of parallel connections to a specified server process operating at a server, the connection request received at the server on a communication port; transmitting a list of available server ports to the client in response to the connection request; receiving a first request from the client for a connection to a first one of the available server ports, the first request received at the server on said communication port; accepting a first connection to the client, the first connection accepted at the server on said communication port; creating a first process at the server to manage the first connection to the client on said communication port; establishing a first local connection to the specified server process, the connection established by the first process to the first one of the available server ports on the specified server process; receiving a second request from the client for a connection to a second one of the available server ports, the second request received at the server on said communication port; accepting a second connection to the client, the second connection accepted at the server on said communication port; creating a second process at the server to manage the second connection to the client on said communication port; establishing a second local connection to the specified server process, the connection established by the second process to the second one of the available server ports on the specified server process; and executing a data transfer between the specified server process and the client, wherein the data transfer occurs in parallel on the first connection and the second connection at the server on said communication port, and wherein the first process and the second process relay data between the first and second ones of the available server ports on the specified server process and the client via the first connection and the second connection at the server on said communication port. 2. The method of claim 1, wherein the first process and second process are created by and are child processes of a control process operating at the server. 3. The method of claim 2, wherein creating a first process at the server to manage the first connection to the client comprises transferring the first connection on said communication port from the control process to the first process via inheritance. 4. The method of claim 2, wherein creating a second process at the server to manage the first connection to the client-comprises transferring the second connection on said communication port from the control process to the second process via inheritance. 5. The method of claim 1 further comprising: listening on said communication port at the server for other requests from the client for connections to other ones of the available server ports. 6. The method of claim 1 further comprising: receiving a third request from the client for a connection to a third one of the available server ports, the third request received at the server on said communication port; accepting a third connection to the client, the third connection accepted at the server on said communication port; creating a third process at the server to manage the third connection to the client on said communication port; and establishing a third local connection to the specified server process, the connection established by the third process to the third one of the available server ports on the specified server process. 7. The method of claim 1, wherein said communication port is a well-known port. 8. The method of claim 7, wherein the firewall is typically open to the well-known port. 9. The method of claim 7, wherein the firewall typically permits the client to access the well-known port. 10. The method of claim 1, wherein said communication port is a port reserved for communication with clients. 11. A method for increasing data transfer rates in a network including a firewall, the method comprising: accepting a first connection to a client, the first connection accepted at a server on a communication port; creating a first process at the server to manage the first connection to the client, wherein the first process manages the first connection to the client at the server on said communication port; accepting a second connection to the client, the second connection accepted at the server on said communication port; creating a second process at the server to manage the second connection to the client, wherein the second process manages the second connection to the client at the server on said communication port; and transferring data in parallel between the client and the server using the first connection and the second connection at the server on said communication port. 12. The method of claim 11, wherein accepting a first connection to a client comprises accepting the first connection by a control process operating at the server, and wherein accepting a second connection to the client comprises accepting the second connection by the control process operating at the server. 13. The method of claim 12, wherein creating a first process at the server to manage the first connection to the client comprises creating, by the control process, the first process. 14. The method of claim 12, wherein the first process and second process are child processes of the control process operating at the server. 15. The method of claim 12, wherein creating a first process at the server to manage the first connection to the client comprises: creating, by the control process, the first process; and transferring the first connection on said communication port from the control process operating at the server to the first process by inheritance. 16. The method of claim 12, wherein creating a second process at the server to manage the second connection to the client comprises: creating, by the control process, the second process; and transferring the second connection on said communication port from the control process operating at the server to the second process by inheritance. 17. The method of claim 11, wherein the first process and the second process are relay processes operating at the server that relay data between the client and a specified server process on said communication port. 18. The method of claim 11, wherein said communication port is a well-known port. 19. The method of claim 18, wherein the firewall is typically open to the well-known port. 20. The method of claim 18, wherein the firewall permits the client to access the well-known port. 21. The method of claim 11 further comprising: establishing a first local connection between the first process and a specified server process that responds to a request for a connection made by the client; and establishing a second local connection between the second process and the specified server process that responds to a request for a connection made by the client. 22. The method of claim 21 further comprising: transferring data in parallel between the client and the server using the first connection and the local first connection, and the second connection and the local second connection. 23. The method of claim 11 further comprising: accepting a third connection to the client, the third connection accepted at the server on said communication port; and creating a third process at the server to manage the third connection to the client, wherein the third process manages the third connection to the client at the server on said communication port. 24. The method of claim 11 further comprising: listening on said communication port at the server for one or more requests from the client for one or more connections to a specified server process on one or more available server ports. 25. A system for increasing data transfer rates in a network including a firewall, the system comprising: a control process operating at the server that accepts a first connection to a client and a second connection to the client, wherein the first connection and the second connection are accepted at the server on a communication port; a first relay process that receives the first connection transferred by the control process; and a second relay process that receives the second connection transferred by the control process. 26. The system of claim 25, wherein the first relay process manages the first connection to the client at the server on said communication port. 27. The system of claim 26, wherein the second relay process manages the second connection to the client at the server on said communication port. 28. The system of claim 27, wherein the first relay process establishes a first local connection to a specified server process. 29. The system of claim 28, wherein the second relay process establishes a second local connection to the specified server process. 30. The system of claim 29, wherein the first relay process and the second relay process relay data in parallel between the specified server process and the client on the first connection at the server on said communication port and the second connection at the server on said communication port. 31. The system of claim 25, wherein the control process accepts the first connection and the second connection in response to at least two requests from the client to be connected to a specified server process, the at least two requests from the client received by the control process on said communication port at the server. 32. The system of claim 25, wherein the first relay process and the second relay process are created at the server by the control process. 33. The system of claim 25, wherein the first relay process, the second relay process, and the control process are operating system processes running at the server. 34. The system of claim 25, wherein the first relay process inherits the first connection from the control process, and wherein the second relay process inherits the second connection from the control process. 35. The system of claim 25, wherein said communication port is a well-known port. 36. The system of claim 35, wherein the firewall is typically open to the well-known port. 37. The system of claim 35, wherein the firewall permits the client to access the well-known port. 38. A system for increasing data transfer rates in a network including a firewall, the system comprising: a control process that accepts two or more connections to a client at the server on a communication port; a first relay process that maintains a first connection to the client at the server on said communication port, wherein the first relay process is created by and receives the first connection from the control process; a second relay process that maintains a second connection to a client at the server on said communication port, wherein the second relay process is created by and receives the second connection from the control process; a server process that is accessed by the client such that data is transferred between the client and the server over the first connection and the second connection in parallel. 39. A system for increasing data transfer rates in a network including a firewall, the system comprising: request receiving means for receiving a first request from a client for a connection to a first one of a plurality of available server ports and a second request from the client for a connection to a second one of the plurality of available server ports, the first request and the second request received at the server on a communication port; connection accepting means for accepting a first connection and a second connection to the client, the first connection and the second connection accepted at the server on said communication port; and data transfer means for transferring data in parallel between the client and the server using the first connection and the second connection. 40. The system of claim 39, wherein the data transfer means includes: a first connection managing means for managing the first connection between the client and a server process that responds to a request for a connection made by the client; and a second connection managing means for managing the second connection between the client and the server process that responds to a request for a connection made by the client. 41. The system of claim 40, wherein the first connection managing means and the second connection managing means facilitate a collective data transfer in parallel over the first connection and the second connection via said communication port. 42. The system of claim 40, wherein the first connection is transferred from the connection accepting means to the first connection managing means via inheritance. 43. The system of claim 40 further comprising local connection establishing means for establishing a first local connection between the first connection managing means and the server process on a first one of the plurality of available server ports and for establishing a second local connection between the second connection managing means and the server process on a second one of the plurality of available server ports. 44. A system for increasing data transfer rates in a network including a firewall, the system comprising: first connection accepting means for accepting a first connection to a client, the first connection accepted at a server on a communication port; first process creating means for creating a first process to manage the first connection to the client at the server on said communication port; second connection accepting means for accepting a second connection to the client, the second connection accepted at the server on said communication port; and second process creating means for creating a second process to manage the second connection to the client at the server on said communication port. 45. A method of increasing data transfer rates in a network including a firewall, wherein the method is conducted by an operating system control process running at a server, the method comprising: receiving a first request from a client for a connection to a server process, the first request received at the server on a communication port; accepting a first connection to the client, the first connection accepted at the server on said communication port; creating a first child process to manage the first connection to the client, wherein the first connection is transferred to the first child process by inheritance; receiving a second request from the client for a connection to the server process, the second request received at the server on said communication port; and accepting a second connection to the client, the second connection accepted at the server on said communication port. 46. The method of claim 45 further comprising: creating a second child process to manage the second connection to the client, wherein the second connection is transferred to the second child process by inheritance. 47. The method of claim 46 further comprising: executing a collective data transfer between the server process and the client in parallel on the first connection to the client and the second connection to the client, wherein the first child process and the second child process relay data between the client and the server process via said communication port. 48. The method of claim 45, wherein said communication port is a well-known port. 49. The method of claim 45, wherein said communication port is a port reserved for communication with the client. 50. The method of claim 48, wherein the firewall permits the client to access the well-known port. 51. A method of increasing data transfer rates in a network including a firewall, the method comprising: receiving a first request from a client for a connection to a first available port on a server process, the first request received at the server on a communication port; accepting a first connection to the client, the first connection accepted at the server on said communication port; establishing a first local connection to the first available port on the server process; receiving a second request from the client for a connection to a second available port on the server process, the second request received at the server on said communication port; accepting a second connection to the client, the second connection accepted at the server on said communication port; establishing a second local connection to the second available port on the server process; transferring data in parallel between the client and the server process via the first connection, the first local connection, the second connection, and the second local connection. 52. The method of claim 51, wherein the method is conducted by a control process running at the server.
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FIELD OF THE INVENTION The invention generally relates to systems and methods of increasing data transfer rates in high-latency networks with firewalls. BACKGROUND OF THE INVENTION Users of networked computer systems desire to transfer data reliably and efficiently to and from other networked computer systems. The Transfer Control Protocol/Internet Protocol (TCP/IP) provides the ability to,send and receive data to and from various TCP/IP networked computer systems. File transfer protocol (FTP) is one example of a service that runs on a TCP/IP networked computer system. FTP enables large amounts of data to be transferred from a client side to a server side, or vice versa. Services such as FTP typically initiate communication on a reserved communication port on the server. The reserved communication port is sometimes referred to as a “well-known port.” For example, a user of a client machine may request a connection to an FTP server on the well-known port to transmit/receive data to/from the FTP server. The FTP server may respond by establishing a unique connection between the client and the FTP server. A unique connection is determined by an IP address of the client, an IP address of the server, and the port on the server being accessed. Firewalls are used to secure their hosts by screening data transfers between their hosts and their user community. Conventional firewalls are typically programmed to restrict inbound traffic for a particular set of users and/or a particular set of hosts and/or ports. Firewalls decide to pass data based on the type of protocol used for the data transfer, the destination IP address, and/or source IP address. Most firewalls are programmed to pass data on any connection to a well-known port on a server. For example, if a server has a well-known port for an FTP service, a firewall typically passes or otherwise permits data transfers to and from the well-known FTP port. Some services use a single connection to transfer all the data to/from the server. For large transfers of data occurring on a single connection, throughput is limited to that of a single connection. “Latency” refers to the amount of time it takes a block of data to get from one designated point to another, in a network. Conventional systems have attempted to address a problem of slow data transfer in high latency firewalled networks by establishing multiple connections between the client and the server. Some conventional systems establish these multiple connections by allocating ports on a server dynamically. This process typically involves establishing multiple connections between the client and the server, in real time, by assigning each communication channel a new server port. A firewall in the network typically permits the connections to be established provided the firewall is aware of the protocol being used. For example, the firewall may inspect the protocol information associated with a data transfer in order to determine what new ports should be allocated. Thus, the firewall must be able to recognize the protocol information in order to assign the communication channel a port on the server. Using dynamic port allocation, the firewall opens a corresponding communication port in the firewall not otherwise left open for each of the unique connections established between the client and the server. For example, a client may request a large transfer of data from a server, and the client and the server may negotiate to execute the transfer on three parallel connections between the client and the server. As a result, the firewall would open three corresponding communication ports in the firewall for passing the data channeled on each connection and close them once the transfer is complete. Dynamic port allocation is problematic because it leaves the firewall exposed to security risks at three corresponding communication ports. Because the firewall decides to open three corresponding ports to pass data, the part of the network being protected by the firewall is more vulnerable than when the data transfer is being executed on a single connection. Because some firewalls use dynamic port allocation to regulate data traffic, the manufacturers of firewalls-need to be “aware” of the protocols being used to transfer data through the firewall. More specifically, conventional firewalls must be able to recognize and understand protocol information as it passes through the firewall in order to determine what new ports should be allocated. This results in compatibility problems with installed, or otherwise existing, firewalls when new protocols are created. These and other drawbacks exist. SUMMARY OF THE INVENTION The invention generally relates to a system and method of decreasing latency and increasing data transfer rates in a network including a firewall. According to one aspect of the invention, multiple parallel connections may be established between a client and a server using a single server port reserved for communication with a client. Data may be transferred on the multiple parallel connections between an operating system client process and an operating system server process, for example. According to another aspect of the invention, the multiple parallel connections may all be established at the server on a communication port that is typically open through the firewall including, for example, a well-known port (i.e. a port to which the firewall typically permits access). This arrangement may be advantageous, because it enables data transferred on each of the multiple parallel connections to pass through the corresponding opening in the firewall. Because multiple connections may be passed through a single corresponding opening in the firewall, the problems associated with overexposing the protected network at multiple open ports in the firewall may be avoided. Additionally, because the multiple connections may be established on the same communication port at the server, the firewall need not allocate new ports on the server for the data transfer. According to another aspect of the invention, N parallel connections between a communication port at a server and a client may be established. The communication port may be a well-known port or a port reserved for communication with the client. A single collective data transfer may be executed on the N parallel connections, thereby increasing throughput and data transfer rates. If the data transfer rate is primarily limited by network latency, using N parallel connections provides the advantage of increasing the data transfer rate by approximately a factor of N. The number of connections (N) may be determined by the client, by the server, or may be negotiated between the client and the server. According to another aspect of the invention, the N connections may be accepted by a data traffic manager at the server. Typically, a firewall allows any number of connections to be initiated between a client and a server. However, a single process on the server typically receives connections on a given port at the server at any given time. In various embodiments, a single process on the server side may “listen” for connection requests from the client on a communication port, including a well-known port at the server. Once a connection is accepted by this process, the connection may be transferred or “handed off” to another, typically a new process on the server side. In the meantime, the single process on the server side continues to listen for new connection requests. This new server process that receives the connection on the communication port may be a “child” process created by the single process. Thus, a connection between the client and the communication port at the server may remain active, while other connections between the client and the single process on the server side on the communication port are being initiated. According to another aspect of the invention, the data traffic manager may include a control process. The control process may listen on a communication port for connection requests from the client. Once a connection is established, the control process may transfer the connection to another server process that maintains and/or manages the active connection between the client and the communication port at the server. The control process may continue to listen on the communication port for another connection request from the client. The invention may repeat these operations N times to establish N parallel connections between the client and the communication port at the server. Accordingly, the firewall passes any data channeled on these parallel connections, because the firewall “sees” N connections to the server on the same communication port. According to another aspect of the invention, the control process may accept N parallel connections to the client on the communication port, which may include a well-known port at the server. Because more than one connection may be accepted by the control process at a given time, the control process need not transfer a connection to the client to another server process before listening on the communication port for other connection requests. According to another embodiment, the control process may maintain and/or manage the N connections to client on the communication port, without transferring each connection to a new process on the server side. For example, the control process may accept N connections from the client on the communication port at the server. The control process may then establish N local connections to a specified server process, to which the client has requested access. The control process may relay data between the specified server process and the client via the communication port on the server. According to another aspect of the invention, a data traffic manager, which may include a control process, may-manage connections to the server and the server processes. A client may contact the control process of the data traffic manager and request N connections to a server or specified server process. The control process may contact an existing server process, or create a new server process. The control process may inform the server process that the client is requesting N connections to the server process. In response to the control process, the server process may transmit a list of N available server ports on which the client can initiate connections to the server. According to another aspect of the invention, once the client has received a list of N available ports from the specified server process, the client may contact the control process, which is listening at the server on the communication port, to request a first connection to a selected first one of the available ports. The control process may then accept the first connection to the client on the communication port at the server. Once the first connection is accepted, a first relay process may be created by the control process. The control process may then transfer the first connection between the client and the control process on the communication port to the first relay process. The first relay process may be a “child” process of the control process, and the connection may be transferred by inheritance, for example. The first relay process may manage the active first connection, and the control process may then begin listening or continue listening on the communication port for other connection requests from the client. According to another aspect of the invention, the first relay process may be an operating system process running at the server. The first relay process may establish a new local connection to the selected first one of the available ports at the server in order to relay data to and from the specified server process. Once this connection is established, the first relay process is connected to 1) the client via the communication port at the server and 2) the specified server process on the selected first one of the available ports. The first relay process may relay data between the selected first one of the available ports at the specified server process and the client via the communication port at the server. According to another aspect of the invention, the client may contact the control process, which is listening on the communication port at the server, to request a second connection to the specified server process on a selected second one of the available ports. The control process may then accept the second connection to the client on the communication port at the server. Once the second connection is accepted, a second relay process may be created by the control process. The control process may transfer the second connection between the client and the control process to the second relay process. The second relay process may be a “child” process of the control process, and the connection may be transferred by inheritance, for example. The second relay process may manage the active second connection, and the control process may then begin listening or continue listening on the communication port for other connection requests from the client. According to another aspect of the invention, the second relay process may be an operating system process running at the server. The second relay process may establish a new local connection to the selected second one of the available ports at the server in order to relay data to and from the specified server process. Once this connection is established, the second relay process is connected to 1) the client via the communication port at the server and 2) the specified server process on the selected second one of the available ports. The second relay process may relay data between the selected second one of the available ports at the specified server process and the client via the communication port at the server. According to another aspect of the invention, the control process may continue to listen for other connection requests from the client. The control process may ultimately accept N parallel connections and creates N relay processes. A single collective data transfer may be executed on the N connections in parallel, thereby increasing throughput and data transfer rates. According to another aspect of the invention the relay processes may be created to pass data to or from a specified server process to which the client has requested access. These relay processes may be newly created “child” processes of the control process that accepted the connection to the client on the communication port at the server. The relay processes provide the advantage of “freeing” the control process from the burden of continuously passing data between the communication port and the specified server process on the N parallel connections. According to another aspect of the invention, the relay processes maintain N active parallel connections on the communication port at the server. Thus, the specified server process may pass the data to the N relay processes, which subsequently pass the data to the client on the N active parallel connections via the communication port at the server. The firewall may pass the data transferred on the active N parallel connections, because the connections all originate on the same communication port at the server. Because all the connections originate on the communication port at the server, the firewall does not need to allocate ports dynamically, therefore, N multiple parallel connections may be established without the firewall having any knowledge of the underlying protocols. Accordingly, the firewalls that may be used with the invention are not required to recognize the protocols used to transfer data between a client and a server. According to another aspect of the invention, each one of the N local ports on the specified server process may transmit data on N parallel connections to a corresponding local port on each of the N relay processes; and the N relay processes may relay the data to the client via the communication port at the server. According to another aspect of the invention, each of the N relay process s may receive data on each of the N parallel connections from the client via the communication port at the server. The N relay processes may relay the data from the N local ports on the relay processes to the N local ports on the specified server process. According to another aspect of the invention, if the data transfer rate is primarily limited by network latency, using N parallel connections provides the advantage of transferring data at a rate approaching N times faster than if the client and the specified server process had established a single connection for the data transfer. A single collective data transfer may be executed on the N connections in parallel, thereby increasing throughput and data transfer rates. This may be especially advantageous in larger data transfers. In some embodiments of the invention, the data may be split into smaller chunks and passed over the N parallel connections. According to another aspect of the invention, the data traffic manager may be used with any type of existing or subsequently developed protocol for transferring data. Unlike dynamic port allocation, the invention may use the same communication port to initiate all N connections; therefore the firewall need not be aware of the protocol being used to transfer the data. As a result, new protocols may be created and used with existing firewalls that would not otherwise operate with newer protocols. It is to be understood that the invention is not limited to data transfers occurring in a specific network direction (i.e. client to server, server to client, etc.), but encompasses any data transfer in a network including a firewall. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: FIG. 1 is a schematic diagram of a system for increasing data transfer rates according to various embodiments of the invention. FIG. 2 illustrates a process for establishing multiple parallel connections between a client and a server according to various embodiments of the invention. FIG. 3 illustrates a system for increasing data transfer rates including relationships between local ports at the server according to various embodiments of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention generally relates to a system and method that compensates for latency and increases data transfer rates in a network that includes a firewall. FIG. 1 is a schematic diagram of a system for increasing data transfer rates according to one embodiment of the invention. For purposes of illustration, the data transfer has been depicted to occur in the server-to-client direction. However, it is to be understood that the invention is not limited to data transfers occurring in a particular network direction (i.e. client to server, server to client, etc.), but may encompass various data transfers in networks including a firewall. While described below as a well-known port at the server, the following description applies generally to all communication ports in a network. According to the various embodiments of the invention, multiple parallel connections may be established between client 102 and server 101 using a single server communication port 105, which may be a well-known port that is accessible through firewall 104. The source and the target of the data transfer may also include an operating system client process 115 and an operating system server process 114. Firewall 104 may be a conventional firewall that includes various “rules” for determining whether to pass data through the firewall or provide access to various addresses. These rules may include for, for example, instructions to firewall 104 to pass certain data being transferred to/from certain ports on server 101. In the embodiment depicted in FIG. 1, rule A 109 instructs firewall 104 to pass data transferred between client 102 and server 101 via server port A 105. The multiple parallel connections may all be established at server 101 on server port A 105. This arrangement may be advantageous, because it enables data transferred on each of the multiple parallel connections to pass through opening 109 in firewall 104 which corresponds to server port A 105. Because these multiple connections may be passed through a single corresponding opening 109 in firewall 104, the configuration of firewall 104 is simplified and network security is increased. First relay process 106 and second relay process 107 through Nth relay process 108 each manage an active connection with client 102 at server 101 on server port A 105. The relay processes manage data transmitted/received between server process 114 and client 102. Each of the multiple parallel connections may include a local server connection from server process 114 to a relay process (106-108) and a connection from a client process 115 to a relay process. For example, second relay process 107 manages data transferred between server process 114 on server port A 105 and client process 115 on client port Y 111. A single process on the server typically receives connections on a given port at the server at any given time. In other words, one process (e.g. control process 103) on server 101 may “listen” for connection requests from client 102 on a well-known port at server 101. Additionally, nearly all firewalls allow more than one connection between a client and a given port at a server to remain active. Thus, a connection between client 102 and control process 103 on server port A 105 at server 101 may remain active, while other connections between client 102 and control process 103 on server port A 105 are being initiated. Once a connection is initiated, control process 103 may create a new “child” process and “hand off” or transfer the connection to the newly created child process. Because conventional operating systems typically allow a single process on the server to “listen” for a connection request at any given time, some embodiments of the invention repeat the following operations N times to generate N parallel connections between client 102 and a specified server process (e.g. 114) at server 101 on well known-port 105: (1) establish a connection between client 102 and control process 103, which is listening on well-known port 105 at server 101; (2) create a relay process (e.g. 106, 107, and 108) that may be a child process of control process 103; (3) transfer the connection between client 102 and control process 103 on well-known port 105 at server 101 to a relay process; and (3) connect the relay process to specified server process 114 to which client 102 requested a connection on an available server port. In some embodiments, data traffic manager 113 may accept the N connections between client 102 and server 101. Data traffic manager 113 may include control process 103 relay processes, 106-108. Control-process 103 may listen on well-known port 105 at server 101 for connection requests from client 102. Once a connection is established, control process 103 may transfer the connection to another server process (e.g. one of relay processes 106-108) that manages the active connection between client 102 and well-known port 105. Relay processes 106-108 may be child processes of control process 103. Control process 103 may continue to listen on well-known port 105 for another connection request. Control process 103 may repeat these operations N times to generate N parallel connections between client 102 and well-known port 105 at server 101. Accordingly, firewall 104 passes any data channeled on these parallel connections, because firewall 104 “sees” N connections to server 101 on well-known port 105. In a network where latency is the primary factor limiting the data transfer rate, using N parallel connections provides the advantage of increasing the data transfer rate by a factor approaching N. One advantage of the invention is that the data traffic manager 113 may be used with any type of existing or subsequently developed protocol for transferring data. Unlike dynamic port allocation, various embodiments of the invention may use the same communication port to initiate all N connections; therefore firewall 104 need not be aware of the protocol being used to transfer the data. As a result, new protocols may be created and used with existing firewalls that would not otherwise operate with newer protocols. These protocols can be implemented using various software programs located at the client and the server without need to reconfigure the firewall deployed there between. FIG. 2 illustrates a process for establishing multiple parallel connections between client 102 and server 101 via well-known port 105 according to one embodiment of the invention. In an operation 201, client 102 contacts control process 103, which is listening at server 101 on well-known port 105. Client 102 may ask control process 103 for a connection to an existing or non-existing server process 114. The number of connections (i.e. N) to be established may be determined by client 102 or server 101. The number of connections may also be established by negotiations between the client and the server. In an operation 202, control process 103 may contact an existing server process 114, or create a new server process, in response to the request from client 102. Control process 103 may inform server process 114 that client 102 is requesting N connections to server process 114. In an operation 203, server process 114 may transmit a list of N available server ports on which client 102 can initiate connections to server process 114, in response to control process 103. The N available server ports may be ports on server 101. In an operation 204, once client 102 has received a list of N available ports from server process 114, client 102 may contact control process 103 to request a first connection to a selected first one of the N available server ports. Control process 103 may then accept the first connection to client 102 on well-known port 105 at server 101. In an operation 205, once the first connection is accepted, first relay process 106 may be created by control process 103. First relay process 106 may be a child of control process 103. In this manner, control process 103 may then transfer the first connection between client 102 and control process 103 to first relay process 106. This connection may be transferred, for example, by inheritance. First relay process 106 then establishes a connection to server process 114 on a selected first one of the N available server ports. First relay process 106 manages the first connection and relays data between the selected first one of the available server ports and client 102. First relay process 106 provides the advantage of “freeing” control process 103 from having to continuously pass data between the first one of the available server ports on the server process 114 and client 102 via well-known port 105. Control process 103 may then continue listening on well-known port 105 for other connection requests from client 102. In an operation 206, client 102 may contact control process 103, which is listening on well-known port 105 at server 101, to request a second connection to server process 114 on a selected second one of the available ports. Control process 103 may then accept the second connection to client 102 on well-known port 105 at server 101. In an operation 207, once the second connection is accepted, second relay process 107 may be created by control process 103. Second relay process 107 may also be a child of control process 103. In this manner, control process 103 may transfer the second connection between client 102 and control process 103 to second relay process 107. Second relay process 107 then establishes a connection to server process 114 on a selected second one of the N available server ports. Second relay process 107 manages the active second connection on well-known port 105 and relays data between the selected second one of the available server ports and client 102. Second relay process 107 provides the advantage of “freeing” control process 103 from having to continuously pass data between the second one of the available server ports on server process 114 and client 102 via well-known port 105. Control process 103 may then continue listening on well-known port 105 for other connection requests from client 102. In operations 208 and 209, N-2 connections are established between client 102 and server process 114 at server 101 on well-known port 105 in a similar manner that the first and second connections were established in operations 204-207. In operations 210 and 211, client 102 transmits/receives data through firewall 104 on N multiple parallel connections to/from well-known port 105 at server 101. Similarly, server process 114 transmits/receives data on well-known port 105 at server 101. Data received at well-known port 105 is relayed to the corresponding selected available ports; and data transmitted from the corresponding selected available ports is relayed on well-known port 105 at server 101 to client 102. FIG. 3 illustrates a system for increasing data transfer rates including relationships between local ports at the server according to various embodiments of the invention. The relay processes 106, 107, and 310 are created to transfer data between a server process 114 to which the client 102 has requested access, as described above. In this example, relay processes 106, 107, and 310 maintain three active parallel connections on the well-known port 105 at server 101. As would be apparent, any number of relay processes may be used to manage the active parallel connections. Thus, server process 114 may pass the data to the three relay processes 106, 107, and 310, which subsequently pass the data to client 102 on the three active parallel connections via well-known 105 port at server 101. Server process 114, control process 103, and relay processes 106, 107, and 310 may be operating system processes running at server 101, as would be apparent. Similarly, client process 115 may be an operating system process running at client 102, as would also be apparent. As described above, the relay processes 106, 107, and 310 receive active connections from control process 103. In response to receiving an active connection to client 102 on well-known port 105 at server 101, relay processes 106, 107, and 310 may establish new local connections to the selected ones of the available ports 312-314 at server 101 in order to relay data to/from server process 114. For example, first relay process 106 may manage an active connection to client port X 110 via server port A 105. First relay process 106 may initiate a local connection between server port B 312 on server process 114 and server port E 307. First relay process 106 may then relay data between client 102 and server 101 via server port A 105, which in some embodiments is a well-known port. Once this connection is established, first relay process 106 is connected to 1) client 102 at client port X 110 via well-known port A 105 at server 101 and 2) server process 114 on server port B 312. First relay process 106 may relay data between server port B 312 at server process 114 and client 102 via well-known port A 105 at server 101. Firewall 104 passes the data transferred on the active connection between server port B 312 and client port X 110, as discussed above. In a similar manner, a second relay process 107, may initiate a local connection between server port C 313 on server process 114 and server port F 309. Once this connection is established, second relay process 107 is connected to 1) client 102 at client port Y 111 via well-known port A 105 at server 101 and 2) server process 114 on local server port C 313. Second relay process 107 may relay data between server port C 313 at server process 114 and client 102 via well-known port A 105 at server 101. Firewall 104 passes the data transferred on the active connection between server port C 313 and client port Y 111, because the connection originated on well-known port A 105 at server 101. Control process 103 may continue to accept other connections between client 102 and server process 114. The dotted line 321 between the client and control process 103 illustrates that control process 103 may continue to actively listen for additional connection requests then pass, by inheritance, each additional connection to a relay process. Control process 103 may ultimately accept N (in this example three) parallel connections and create N relay processes. As a result, the system 300 may transfer data through firewall 104 on N connections to/from N local server process ports to the client via the same well-known port 105 on the server. In some embodiments, the N local ports on the server process may transmit data on N parallel connections to a corresponding local port on each of the N relay processes; and the N relay processes may relay the data to the client via the well-known port at the server. Similarly, the N relay processes may receive data on each of the N parallel connections from the client via the well-known port at the server. The N relay processes may then relay the data from the N local ports on the relay processes to the N local ports on the server process. Once N connections are established between a server process and the client, data may be transferred at a rate approaching N times faster than if the client and the server process had established a single connection for the data transfer. A single collective data transfer may be executed on the N connections in parallel, thereby increasing throughput and data transfer rates. This may be especially advantageous in larger data transfers. In various embodiments of the invention, the data may be split into smaller chunks and passed over the N parallel connections. In some embodiments, the control process may relay data to/from a specified server process from/to a client on N connections via the well-known port without creating relay processes. In these embodiments, the control process may accept N connections from the client on the well-known port, then establish N local connections to the specified server process. Data may then be relayed between the client and the specified server process by the control process via the well-known port at the server. Again, it is to be understood that the invention is not limited to data transfers occurring in specific network direction (i.e. client to server, server to client, etc.), but encompasses any data transfer in a network including a firewall. Various embodiments of the invention may be implemented to increase data transfer rates to/from any network entity. In addition, various embodiments of the invention may be used at the client side or at the server side or at a combination thereof. It should also be understood that various embodiments of the invention may be implemented in software, hardware, or on a combination thereof. Additional features and advantages of the invention are set forth in the description that follows, and in part are apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention are realized and gained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. Although particular embodiments of the invention have been shown and described, it will be understood that it is not intended to limit the invention to the embodiments described above and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the invention as defined by the claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Users of networked computer systems desire to transfer data reliably and efficiently to and from other networked computer systems. The Transfer Control Protocol/Internet Protocol (TCP/IP) provides the ability to,send and receive data to and from various TCP/IP networked computer systems. File transfer protocol (FTP) is one example of a service that runs on a TCP/IP networked computer system. FTP enables large amounts of data to be transferred from a client side to a server side, or vice versa. Services such as FTP typically initiate communication on a reserved communication port on the server. The reserved communication port is sometimes referred to as a “well-known port.” For example, a user of a client machine may request a connection to an FTP server on the well-known port to transmit/receive data to/from the FTP server. The FTP server may respond by establishing a unique connection between the client and the FTP server. A unique connection is determined by an IP address of the client, an IP address of the server, and the port on the server being accessed. Firewalls are used to secure their hosts by screening data transfers between their hosts and their user community. Conventional firewalls are typically programmed to restrict inbound traffic for a particular set of users and/or a particular set of hosts and/or ports. Firewalls decide to pass data based on the type of protocol used for the data transfer, the destination IP address, and/or source IP address. Most firewalls are programmed to pass data on any connection to a well-known port on a server. For example, if a server has a well-known port for an FTP service, a firewall typically passes or otherwise permits data transfers to and from the well-known FTP port. Some services use a single connection to transfer all the data to/from the server. For large transfers of data occurring on a single connection, throughput is limited to that of a single connection. “Latency” refers to the amount of time it takes a block of data to get from one designated point to another, in a network. Conventional systems have attempted to address a problem of slow data transfer in high latency firewalled networks by establishing multiple connections between the client and the server. Some conventional systems establish these multiple connections by allocating ports on a server dynamically. This process typically involves establishing multiple connections between the client and the server, in real time, by assigning each communication channel a new server port. A firewall in the network typically permits the connections to be established provided the firewall is aware of the protocol being used. For example, the firewall may inspect the protocol information associated with a data transfer in order to determine what new ports should be allocated. Thus, the firewall must be able to recognize the protocol information in order to assign the communication channel a port on the server. Using dynamic port allocation, the firewall opens a corresponding communication port in the firewall not otherwise left open for each of the unique connections established between the client and the server. For example, a client may request a large transfer of data from a server, and the client and the server may negotiate to execute the transfer on three parallel connections between the client and the server. As a result, the firewall would open three corresponding communication ports in the firewall for passing the data channeled on each connection and close them once the transfer is complete. Dynamic port allocation is problematic because it leaves the firewall exposed to security risks at three corresponding communication ports. Because the firewall decides to open three corresponding ports to pass data, the part of the network being protected by the firewall is more vulnerable than when the data transfer is being executed on a single connection. Because some firewalls use dynamic port allocation to regulate data traffic, the manufacturers of firewalls-need to be “aware” of the protocols being used to transfer data through the firewall. More specifically, conventional firewalls must be able to recognize and understand protocol information as it passes through the firewall in order to determine what new ports should be allocated. This results in compatibility problems with installed, or otherwise existing, firewalls when new protocols are created. These and other drawbacks exist.
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<SOH> SUMMARY OF THE INVENTION <EOH>The invention generally relates to a system and method of decreasing latency and increasing data transfer rates in a network including a firewall. According to one aspect of the invention, multiple parallel connections may be established between a client and a server using a single server port reserved for communication with a client. Data may be transferred on the multiple parallel connections between an operating system client process and an operating system server process, for example. According to another aspect of the invention, the multiple parallel connections may all be established at the server on a communication port that is typically open through the firewall including, for example, a well-known port (i.e. a port to which the firewall typically permits access). This arrangement may be advantageous, because it enables data transferred on each of the multiple parallel connections to pass through the corresponding opening in the firewall. Because multiple connections may be passed through a single corresponding opening in the firewall, the problems associated with overexposing the protected network at multiple open ports in the firewall may be avoided. Additionally, because the multiple connections may be established on the same communication port at the server, the firewall need not allocate new ports on the server for the data transfer. According to another aspect of the invention, N parallel connections between a communication port at a server and a client may be established. The communication port may be a well-known port or a port reserved for communication with the client. A single collective data transfer may be executed on the N parallel connections, thereby increasing throughput and data transfer rates. If the data transfer rate is primarily limited by network latency, using N parallel connections provides the advantage of increasing the data transfer rate by approximately a factor of N. The number of connections (N) may be determined by the client, by the server, or may be negotiated between the client and the server. According to another aspect of the invention, the N connections may be accepted by a data traffic manager at the server. Typically, a firewall allows any number of connections to be initiated between a client and a server. However, a single process on the server typically receives connections on a given port at the server at any given time. In various embodiments, a single process on the server side may “listen” for connection requests from the client on a communication port, including a well-known port at the server. Once a connection is accepted by this process, the connection may be transferred or “handed off” to another, typically a new process on the server side. In the meantime, the single process on the server side continues to listen for new connection requests. This new server process that receives the connection on the communication port may be a “child” process created by the single process. Thus, a connection between the client and the communication port at the server may remain active, while other connections between the client and the single process on the server side on the communication port are being initiated. According to another aspect of the invention, the data traffic manager may include a control process. The control process may listen on a communication port for connection requests from the client. Once a connection is established, the control process may transfer the connection to another server process that maintains and/or manages the active connection between the client and the communication port at the server. The control process may continue to listen on the communication port for another connection request from the client. The invention may repeat these operations N times to establish N parallel connections between the client and the communication port at the server. Accordingly, the firewall passes any data channeled on these parallel connections, because the firewall “sees” N connections to the server on the same communication port. According to another aspect of the invention, the control process may accept N parallel connections to the client on the communication port, which may include a well-known port at the server. Because more than one connection may be accepted by the control process at a given time, the control process need not transfer a connection to the client to another server process before listening on the communication port for other connection requests. According to another embodiment, the control process may maintain and/or manage the N connections to client on the communication port, without transferring each connection to a new process on the server side. For example, the control process may accept N connections from the client on the communication port at the server. The control process may then establish N local connections to a specified server process, to which the client has requested access. The control process may relay data between the specified server process and the client via the communication port on the server. According to another aspect of the invention, a data traffic manager, which may include a control process, may-manage connections to the server and the server processes. A client may contact the control process of the data traffic manager and request N connections to a server or specified server process. The control process may contact an existing server process, or create a new server process. The control process may inform the server process that the client is requesting N connections to the server process. In response to the control process, the server process may transmit a list of N available server ports on which the client can initiate connections to the server. According to another aspect of the invention, once the client has received a list of N available ports from the specified server process, the client may contact the control process, which is listening at the server on the communication port, to request a first connection to a selected first one of the available ports. The control process may then accept the first connection to the client on the communication port at the server. Once the first connection is accepted, a first relay process may be created by the control process. The control process may then transfer the first connection between the client and the control process on the communication port to the first relay process. The first relay process may be a “child” process of the control process, and the connection may be transferred by inheritance, for example. The first relay process may manage the active first connection, and the control process may then begin listening or continue listening on the communication port for other connection requests from the client. According to another aspect of the invention, the first relay process may be an operating system process running at the server. The first relay process may establish a new local connection to the selected first one of the available ports at the server in order to relay data to and from the specified server process. Once this connection is established, the first relay process is connected to 1) the client via the communication port at the server and 2) the specified server process on the selected first one of the available ports. The first relay process may relay data between the selected first one of the available ports at the specified server process and the client via the communication port at the server. According to another aspect of the invention, the client may contact the control process, which is listening on the communication port at the server, to request a second connection to the specified server process on a selected second one of the available ports. The control process may then accept the second connection to the client on the communication port at the server. Once the second connection is accepted, a second relay process may be created by the control process. The control process may transfer the second connection between the client and the control process to the second relay process. The second relay process may be a “child” process of the control process, and the connection may be transferred by inheritance, for example. The second relay process may manage the active second connection, and the control process may then begin listening or continue listening on the communication port for other connection requests from the client. According to another aspect of the invention, the second relay process may be an operating system process running at the server. The second relay process may establish a new local connection to the selected second one of the available ports at the server in order to relay data to and from the specified server process. Once this connection is established, the second relay process is connected to 1) the client via the communication port at the server and 2) the specified server process on the selected second one of the available ports. The second relay process may relay data between the selected second one of the available ports at the specified server process and the client via the communication port at the server. According to another aspect of the invention, the control process may continue to listen for other connection requests from the client. The control process may ultimately accept N parallel connections and creates N relay processes. A single collective data transfer may be executed on the N connections in parallel, thereby increasing throughput and data transfer rates. According to another aspect of the invention the relay processes may be created to pass data to or from a specified server process to which the client has requested access. These relay processes may be newly created “child” processes of the control process that accepted the connection to the client on the communication port at the server. The relay processes provide the advantage of “freeing” the control process from the burden of continuously passing data between the communication port and the specified server process on the N parallel connections. According to another aspect of the invention, the relay processes maintain N active parallel connections on the communication port at the server. Thus, the specified server process may pass the data to the N relay processes, which subsequently pass the data to the client on the N active parallel connections via the communication port at the server. The firewall may pass the data transferred on the active N parallel connections, because the connections all originate on the same communication port at the server. Because all the connections originate on the communication port at the server, the firewall does not need to allocate ports dynamically, therefore, N multiple parallel connections may be established without the firewall having any knowledge of the underlying protocols. Accordingly, the firewalls that may be used with the invention are not required to recognize the protocols used to transfer data between a client and a server. According to another aspect of the invention, each one of the N local ports on the specified server process may transmit data on N parallel connections to a corresponding local port on each of the N relay processes; and the N relay processes may relay the data to the client via the communication port at the server. According to another aspect of the invention, each of the N relay process s may receive data on each of the N parallel connections from the client via the communication port at the server. The N relay processes may relay the data from the N local ports on the relay processes to the N local ports on the specified server process. According to another aspect of the invention, if the data transfer rate is primarily limited by network latency, using N parallel connections provides the advantage of transferring data at a rate approaching N times faster than if the client and the specified server process had established a single connection for the data transfer. A single collective data transfer may be executed on the N connections in parallel, thereby increasing throughput and data transfer rates. This may be especially advantageous in larger data transfers. In some embodiments of the invention, the data may be split into smaller chunks and passed over the N parallel connections. According to another aspect of the invention, the data traffic manager may be used with any type of existing or subsequently developed protocol for transferring data. Unlike dynamic port allocation, the invention may use the same communication port to initiate all N connections; therefore the firewall need not be aware of the protocol being used to transfer the data. As a result, new protocols may be created and used with existing firewalls that would not otherwise operate with newer protocols. It is to be understood that the invention is not limited to data transfers occurring in a specific network direction (i.e. client to server, server to client, etc.), but encompasses any data transfer in a network including a firewall. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
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20040630
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20090428
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20060302
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75834.0
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G06F1516
| 0
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AVELLINO, JOSEPH E
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SYSTEM AND METHOD FOR TRANSFERRING DATA IN HIGH LATENCY FIREWALLED NETWORKS
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SMALL
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ACCEPTED
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G06F
| 2,004
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10,879,588
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ACCEPTED
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Bandpass filter with integrated variable gain function using improved resistor array
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The invention enables a gain adjustment in a receiver to improve signal quality by varying resistance of an input resistor array of a bandpass filter, the array having a plurality of resistors in series with switches that out of the path of the current when the resistors are in use.
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1. A method, comprising: filtering a signal with a bandpass filter; measuring the signal to noise ratio of the filtered signal; and adjusting the bandpass filter to increase the gain if the signal to noise ratio is insufficient by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use. 2. The method of claim 1, further comprising: measuring image rejection and DC offset rejection of the filtered signal; and adjusting a center frequency of the bandpass filter. 3. The method of claim 1, wherein the bandpass filter comprises two cross-coupled low pass filters. 4. The method of claim 3, wherein the cross-coupling includes cross-coupled variable resistors. 5. The method of claim 4, wherein adjusting the resistance of the cross-coupled resistors varies the center frequency of the bandpass filter. 6. The method of claim 1, wherein the switches are located perpendicular to and between the resistors. 7. The method of claim 1, wherein the bandpass filter gain is adjustable between 0 and 30 db in 10 db steps. 8. A system, comprising: means for filtering a signal with a bandpass filter; means for measuring sufficiency of the signal to noise ratio of the filtered signal; and means for adjusting the bandpass filter to increase the gain if the signal to noise ratio is insufficient by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use. 9. A system, comprising: a bandpass filter capable of filtering a received signal and capable of amplifying an amplitude of the received signal by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use; and at least one baseband circuit, communicatively coupled to the bandpass filter, capable of measuring sufficiency of the signal to noise ratio of a signal output from the bandpass filter. 10. The system of claim 9, wherein the bandpass filter can vary the amplification of the received signal based on feedback from the baseband circuit. 11. The system of claim 9, further comprising at least one measurement, communicatively coupled to the filter, capable of measuring image rejection and DC offset rejection, and wherein the bandpass filter is capable of adjusting a center frequency of the filter based on the measuring. 12. The system of claim 9, wherein the bandpass filter comprises two cross-coupled low pass filters. 13. The system of claim 12, wherein the cross-coupling includes cross-coupled variable resistors. 14. The system of claim 13, wherein adjusting the resistance of the cross-coupled resistors varies the center frequency of the bandpass filter. 15. The system of claim 9, wherein the switches are located perpendicular to and between the resistors 16. The system of claim 9, wherein the bandpass filter gain is adjustable between 0 and 30 db in 10 db steps. 17. A receiver incorporating the system of claim 9.
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CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of, and incorporates by reference, U.S. patent application Ser. No. 10/840,271, filed May 7, 2004, entitled “Bandpass Filter With Integrated Variable Gain Function” by inventor Meng-An Pan, which is a continuation-in-part of, and incorporates by reference, U.S. patent application Ser. No. 10/813,270, filed Mar. 31, 2004, entitled “Programmable IF Frequency Filter For Enabling A Compromise Between DC Offset Rejection And Image Rejection” by inventor Meng-An Pan. BACKGROUND 1. Technical Field This invention relates generally to wireless communication systems, and more particularly, but not exclusively, to a bandpass filter with integrated variable gain function. 2. Description of the Related Art Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), and/or variations thereof. Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, et cetera communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channel pair (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system) and communicate over that channel or channel pair. For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the internet, and/or via some other wide area network. For each wireless communication device to participate in wireless communications, it includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). As is known, the receiver receives RF signals, removes the RF carrier frequency from the RF signals directly or via one or more intermediate frequency stages, and demodulates the signals in accordance with a particular wireless communication standard to recapture the transmitted data. The transmitter converts data into RF signals by modulating the data to RF carrier in accordance with the particular wireless communication standard and directly or in one or more intermediate frequency stages to produce the RF signals. Bandpass filters (BPFs) in receivers can incorporate gain setting functions. However, the conventional technique of gain settings may not be accurate due to resistance of switches in an input resistor array. Accordingly, a new method of gain control is implemented such that the BPF can have gain that is less dependent on the switch on resistance. SUMMARY Embodiments of the invention incorporate variable gain settings in a bandpass filter such that gain is less dependent on the switch on resistance. In an embodiment of the invention, a system comprises a bandpass filter and a baseband circuit coupled together. The bandpass filter filters a received signal and amplifies an amplitude of the received signal by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use. The baseband circuit measures sufficiency of the signal to noise ratio of a signal output from the bandpass filter and provides feedback to the bandpass filter to adjust gain accordingly so that overall noise performance is improved. In an embodiment of the invention, a method comprises: filtering a signal with a bandpass filter; measuring signal quality (e.g., signal to noise ratio) of the filtered signal; and adjusting the bandpass filter to increase the gain if required to improve signal quality by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use. BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. FIG. 1 is a block diagram illustrating a network system according to an embodiment of the present invention; FIG. 2 is a circuit diagram illustrating a receiver; FIG. 3A and FIG. 3B are charts illustrating variable gain in the bandpass filter of the receiver of FIG. 2 and corresponding noise figures; FIGS. 4A and 4B are diagrams illustrating a channel select filter (bandpass filter) of the receiver IF section of FIG. 2 and its electrical equivalent, respectively; FIG. 5 is a flowchart illustrating a method for variable gain selection in the filter. FIG. 6 is a diagram illustrating a bandpass filter of the receiver IF section of FIG. 2 according to an embodiment of the invention; and FIG. 7 is a diagram illustrating a bandpass filter of the receiver IF section of FIG. 2 according to an embodiment of the invention. DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS The following description is provided to enable any person having ordinary skill in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles, features and teachings disclosed herein. FIG. 1 is a block diagram illustrating a network system 10 according to an embodiment of the present invention. The system 10 includes a plurality of base stations and/or access points 12-16, a plurality of wireless communication devices 18-32 and a network hardware component 34. The wireless communication devices 18-32 may be laptop host computers 18 and 26, personal digital assistant hosts 20 and 30, personal computer hosts 24 and 32 and/or cellular telephone hosts 22 and 28. The base stations or access points 12 are operably coupled to the network hardware 34 via local area network connections 36, 38 and 40. The network hardware 34, which may be a router, switch, bridge, modem, system controller, etc. provides a wide area network connection 42 for the communication system 10. Each of the base stations or access points 12-16 has an associated antenna or antenna array to communicate with the wireless communication devices in its area. Typically, the wireless communication devices register with a particular base station or access point 12-14 to receive services from the communication system 10. For direct connections (i.e., point-to-point communications), wireless communication devices communicate directly via an allocated channel. Typically, base stations are used for cellular telephone systems and like-type systems, while access points are used for in-home or in-building wireless networks. Regardless of the particular type of communication system, each wireless communication device includes a built-in radio and/or is coupled to a radio. The radio includes a transmitter capable of adjusting power amplifier output power and therefore has characteristics of reduced power requirements, thereby extending the life of an associated power supply. FIG. 2 is a circuit diagram illustrating a receiver 200 with low-intermediate frequency, which is 100 KHz in this embodiment. An antenna 205 is coupled to a low noise amplifier (LNA) 210, which is coupled to down converters (mixers) 220 and 225. The down converters 220 and 225 are coupled to bandpass filters (BPFs) 230 and 235, respectively, which are coupled to programmable gain amplifiers 240 and 245, respectively. The gain amplifiers 240 and 245 output analog signals to baseband digital processing circuits 285 and 290, respectively. Further, an LO generator 280 is coupled to the down converters 220 and 225. A wideband radio signal strength indicator (WRSSI) 215 is coupled to connections between the down converters 220 and 225 and the bandpass filters 230 and 235. The antenna 205 receives signals and passes the signals to the LNA 210, which amplifies the received signals and passes them to the down converters 220 and 225, which shifts the frequency of the received signals downwards. The BPFs 230 and 235 discriminate against unwanted frequencies outside of a selected band. The BPFs 230 and 235 also perform channel selection to compromise between image rejection and DC offset rejection and further perform gain functions, as will be discussed in further detail below. In an embodiment of the invention, each BPF 230 and 235 can comprise 3 biquads with configurations as shown in Table I below. TABLE I (Center Frequency of 100 KHz) Biquad1 Biquad2 Biquad3 Center 100 KHz 186 KHz 13.4 KHz Frequency BW 200 KHz 100 KHz 100 KHz Q 0.5 1.866 0.134 Gain Setting 20 dB, 0 dB 10 dB, 0 dB 0 dB 30 dB 20 dB 10 dB 0 dB 20 dB 20 dB 0 dB 0 dB 10 dB 0 dB 10 dB 0 dB 0 dB 0 dB 0 dB 0 dB Current 1.7 mA (I and Q) 1.7 mA (I and Q) 1.7 mA (I and Q) Each BPF 230 and 235 can have gain settings of 30 dB, 20 dB, 10 dB and 0 dB. IF can be centered at 112 KHz, 108 KHz, 104 KHz, and 100 KHz. Further, the BPFs 230 and 235 can change the IQ polarity. Control words will vary the coupling resistor 410 values, which is Rx in FIG. 4, and change the IF frequency of the channel select filter 400. Control words for changing the channel selection (frequency selection) of the BPFs 230 and 235 are shown in Table II below. TABLE II Center Frequency BPF Center Frequency Control Word (4 bit) 112 KHz 1000 108 KHz 0100 104 KHz 0010 100 KHz 0001 Control words also vary Rf and Ri (FIG. 4A) values to change the gain of the bandpass filter 230 and 235. As shown in FIG. 3A, in an embodiment of the invention, the BPFs 230 and 235 can have variable gain from 0 db to 30 db in 10 db steps. Control words for the varying gain are shown in Table III below. It will be appreciated by one of ordinary skill in the art that the gain settings are not limited to the values shown in Table III. TABLE III Gain Gain Control Word (2 bit) Noise Figure @ 100 KHz 30 db 11 18.9 20 db 10 21 10 db 01 39 0 db 00 41 The LO generator 280 determines how to bring an incoming RF signal received at the antenna 205 down to 100 KHz. The PGAs 240 and 245 increase the gain of the BPFs 230 and 235 output. The baseband digital processing circuits 285 and 290 convert analog signals from the PGAs 240 and 245 to digital data and determine if the current gain is adequate (e.g., if signal to noise ratio too low). The baseband digital processing circuits 285 and 290 then adjust the BPF 230 and 235 gain function accordingly by varying Rf and Ri (FIG. 4A). In an embodiment of the invention, the receiver 200 can include measurement circuits (not shown) in place of or in addition to the baseband digital processing circuits 285 and 290 that measure the DC offset rejection and image rejection of the filtered signals and provide feedback to the BPFs 230 and 235 so that a new IF frequency can be chosen to form a better compromise between DC offset rejection and image rejection. FIG. 3A is a chart illustrating variable gain in the bandpass filter of the receiver of FIG. 2. Gain can be varied by the variation of resistance in the BPFs 230 and 235 as derived below based on the circuits shown in FIG. 4A and FIG. 4B below. Resistance variation (for resistors 410 in FIG. 4A) also enables IF frequency shifting to compensate for DC offset rejection and image rejection. For a low pass filter: y x = Gain 1 + j ω ω 0 , wherein ωo is the corner frequency. For a bandpass filter: y x = Gain 1 + j ( ω - ω c ) ω 0 , wherein ωc is the center frequency. Therefore, for the channel select filter electrical equivalent 420 (FIG. 4B): y x = Gain j W W 0 + 1 - j2Q = Gain 1 + j ( ω ω o - 2 Q ) = Gain 1 + j ω - 2 Q ω o ω o = Gain 1 + j ω - ω c ω o Therefore , ω o = 1 R f C ω c = 1 R x C Q = ω c 2 ω o Gain = R f R i FIG. 3B are charts showing noise figures for the BPFs 230 and 235. As gain is increased, noise decreases, thereby improving the signal to noise ratio. FIG. 4A and FIG. 4B are diagrams illustrating a BPF 400 (e.g., the bandpass filters 230 and 235) and its electrical equivalent, respectively. The filter 400 is an active RC filter that enables achievement of a high dynamic range. The filter 400 comprises two cross coupled low pass filters having cross coupled variable resistors 410, each having a resistance Rx. As derived above, variation of Rx shifts the bandpass filter IF frequency up or down. Specifically, the IF frequency of the filter 400 is inversely proportional to Rx. In addition, variation of a feedback resistor, Rf, and of an input resistor, Ri, enable changes in gain of the filter 400 as gain is equal to Rf/Ri. Rf and Ri are set to default values (e.g., zero gain) initially and gain, if any, is applied. After filtering and amplification (by the PGAs 240, 245), the baseband digital processing circuits 285 and 290 determine if the gain is adequate based on the signal to noise ratio. If the gain is insufficient, then the baseband digital processing circuits 285 and 290 provide feedback to the BPFs 230 and 235 and Rf and Ri are adjusted to increase gain in the BPFs 230 and 235. In an embodiment of the invention, Ri can include the resistor arrays structures shown in FIG. 6 and/or FIG. 7. FIG. 5 is a flowchart illustrating a method 500 for variable gain selection in the filter 400. In an embodiment of the invention, the filter 400, 600 or 700 (e.g., the BPFs 230 and 235) and the baseband digital processing circuits 285 and 290 perform the method 500. First, gain in the filter 400 is set (510) to a default setting (e.g., 0 by setting Rf and Ri to be equal to each other). Next, the signal is amplified (520) according to the setting. The signal to noise ratio is then measured (530). If (540) it is determined that the gain is sufficient because the signal to noise ratio is sufficient, the method 500 then ends. Otherwise, the gain setting is adjusted (550) upwards and the amplifying (520), measuring (530), and determining (540) are repeated until the signal to noise ratio is adequate. In an embodiment of the invention, the measuring (530) can determine if the gain is appropriate (too high or too low) and the adjusting (550) can adjust the gain up or down accordingly. FIG. 6 is a diagram illustrating a BPF 600 of the receiver IF section of FIG. 2 according to an embodiment of the invention. The BPF 600 is substantially similar to the BPF 400 except that the resistor array structure of Ri is shown in more detail. The BPF 600 (e.g., the bandpass filters 230 and 235) includes two variable resistors Ri. Each of the variable resistors Ri can comprise 3 resistors, Ri1, Ri2, and Ri3, in parallel with a switch, S1, S2, and S3, for each resistor, respectively. Gain for the BPF 600 is equal to Rf/Ri. Ri1, Ri2, and Ri3 can each have equal or different resistances. Three gain settings are achieved. With S1 on and S2, S3 off Gain will be Rf/Ri1. With S2 on and S1, S3 off Gain will be Rf/Ri2. With S3 on and S1, S3 off Gain will be Rf/Ri3. However, each switch itself provides a small resistance, which must be added to the resistance of each resistor, thereby decreasing gain to less than what was designed. Rf can also be variable and share a similar array structure as Ri. FIG. 7 is a diagram illustrating a BPF 700 (e.g., the bandpass filters 230 and 235) of the receiver IF section of FIG. 2 according to an embodiment of the invention. The BPF 700 is substantially similar to the BPF 400 except for the resistor array structure of Ri. Gain is equal to Rf/Ri, wherein Ri comprises a plurality of resistors R1, R2, and R3 coupled in series. Each of the resistors can have equal or different resistances. Capacitors run in parallel with the resistors R2 and R3 as well as Rf. Switches are located perpendicular to the resistors (e.g., out of the path of the resistors). Specifically, S1 is perpendicularly coupled between R1 and R2; S2 is perpendicularly coupled between R2 and R3; and S3 is perpendicularly coupled between R2 and Rf. As such, the switches are outside of the path of the current flow and therefore do not add their own resistance to Ri, thereby increasing the accuracy of gain settings. Specifically, with S1 on and S2, S3 off, the gain will be (Rf+R3+R2)/(R1). With S2 on and S1, S3 off, the gain will be (Rf+R3)/(R1+R2). With S3 on and S1, S3 off, the gain will be (Rf)/(R1+R2+R3). In other words, gain settings are independent of any switch resistance. In an embodiment of the invention, Rf can have structure similar to Ri. The gain settings of the BPF in this embodiment are 20 dB, 10 dB and 0 dB which are equivalent gains of 10, 3.16 and 1, respectively. Therefore Rf, R1, R2, R3 are chosen such that: 20 dB=20 log (10)=S1 on, S2 off, S3 off=(Rf+R3+R2)/(R1) 10 dB=20 log (3.16)=S1 off, S2 on, S3 off=(Rf+R3)/(R1+R2) 0 dB=20 log (1)=S1 off, S2 off, S3 on=(Rf)/(R1+R2+R3) The foregoing description of the illustrated embodiments of the present invention is by way of example only, and other variations and modifications of the above-described embodiments and methods are possible in light of the foregoing teaching. Components of this invention may be implemented using a programmed general purpose digital computer, using application specific integrated circuits, or using a network of interconnected conventional components and circuits. Connections may be wired, wireless, modem, etc. The embodiments described herein are not intended to be exhaustive or limiting. The present invention is limited only by the following claims.
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<SOH> BACKGROUND <EOH>1. Technical Field This invention relates generally to wireless communication systems, and more particularly, but not exclusively, to a bandpass filter with integrated variable gain function. 2. Description of the Related Art Communication systems are known to support wireless and wire lined communications between wireless and/or wire lined communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), and/or variations thereof. Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, home entertainment equipment, et cetera communicates directly or indirectly with other wireless communication devices. For direct communications (also known as point-to-point communications), the participating wireless communication devices tune their receivers and transmitters to the same channel or channel pair (e.g., one of the plurality of radio frequency (RF) carriers of the wireless communication system) and communicate over that channel or channel pair. For indirect wireless communications, each wireless communication device communicates directly with an associated base station (e.g., for cellular services) and/or an associated access point (e.g., for an in-home or in-building wireless network) via an assigned channel. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the internet, and/or via some other wide area network. For each wireless communication device to participate in wireless communications, it includes a built-in radio transceiver (i.e., receiver and transmitter) or is coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). As is known, the receiver receives RF signals, removes the RF carrier frequency from the RF signals directly or via one or more intermediate frequency stages, and demodulates the signals in accordance with a particular wireless communication standard to recapture the transmitted data. The transmitter converts data into RF signals by modulating the data to RF carrier in accordance with the particular wireless communication standard and directly or in one or more intermediate frequency stages to produce the RF signals. Bandpass filters (BPFs) in receivers can incorporate gain setting functions. However, the conventional technique of gain settings may not be accurate due to resistance of switches in an input resistor array. Accordingly, a new method of gain control is implemented such that the BPF can have gain that is less dependent on the switch on resistance.
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<SOH> SUMMARY <EOH>Embodiments of the invention incorporate variable gain settings in a bandpass filter such that gain is less dependent on the switch on resistance. In an embodiment of the invention, a system comprises a bandpass filter and a baseband circuit coupled together. The bandpass filter filters a received signal and amplifies an amplitude of the received signal by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use. The baseband circuit measures sufficiency of the signal to noise ratio of a signal output from the bandpass filter and provides feedback to the bandpass filter to adjust gain accordingly so that overall noise performance is improved. In an embodiment of the invention, a method comprises: filtering a signal with a bandpass filter; measuring signal quality (e.g., signal to noise ratio) of the filtered signal; and adjusting the bandpass filter to increase the gain if required to improve signal quality by varying resistance of an input resistor array of the filter, the array having a plurality of resistors in series with switches that are out of the path of the current when the resistors are in use.
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20040630
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20080520
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20051006
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86496.0
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LE, LANA N
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BANDPASS FILTER WITH INTEGRATED VARIABLE GAIN FUNCTION USING IMPROVED RESISTOR ARRAY
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UNDISCOUNTED
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CONT-ACCEPTED
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10,879,640
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ACCEPTED
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Apparatus for distributing content objects to a personalized access point of a user over a network-based environment and method
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An apparatus is provided for distributing content objects to a personalized access point of a user over a network-based environment. The apparatus includes a server, a selection client, and a retrieval client. The server includes a database operative to store indicia associated with at least one content object and further operative to store user identifiers as well as information about which content objects have been selected by a particular user. The selection client communicates with the server via a communication link. The selection client is configured to allow a user to select content objects to add to a personalized access point by submitting an indicia and a user identifier to the server. The retrieval client communicates with the server over a communication link allowing a user to retrieve information from a personalized access point. In response to the submission of the indicia and user identifier, at least one of: (a) a content object, and (b) a link to a content object are added to the personalized access point of the particular user and the particular user can retrieve the content object through the personalized access point from the retrieval client. A method is also provided.
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1. An apparatus for distributing content objects to a personalized access point of a user over a network based environment, comprising: a server including a database operative to store indicia associated with at least one content object and further operative to store user identifiers as well as information about which content objects have been selected by a particular user; a selection client communicating with the server via a communication link and configured to allow a user to select content objects to add to a personalized access point by submitting an indicia and a user identifier to the server; and a retrieval client communicating with the server over a communication link allowing a user to retrieve information from a personalized access point; wherein, in response to submission of the indicia and user identifier, at least one of: (a) a content object, and (b) a link to a content object are added to the personalized access point of the particular user and wherein the particular user can retrieve the content object through their personalized access point from the retrieval client. 2. The apparatus of claim 1 wherein the selection client is comprised of at least one of a personal computer, a wireless client, a networked cash register, a bar code scanner, and an electronic product code reader. 3. The apparatus of claim 1 wherein the selection client comprises one of: a web page, a computer kiosk, and a computer readable file storage medium. 4. The apparatus of claim 1 wherein the selection client is further configured to accept payment of content access fees, wherein the payment enables access to the selected content for a predetermined length of time. 5. The method of claim 1 wherein the retrieval client is further configured to limit access to content which requires an access fee if the current date is greater than the content selection date plus the pre-determined length of time. 6. The apparatus of claim 1 wherein the indicia is provided in a visually perceptible location on at least one of: a web page, an email message, a label, a brochure, a pamphlet, a product, product documentation, a product package, a billboard, a sign, and an advertisement. 7. The apparatus of claim 2 wherein the selection client is configured to allow another person to interact with the selection client on behalf of the user. 8. The apparatus of claim 2 where the selection client is a wireless client, and further comprising a wireless network, and wherein the wireless client has a user interface operative to submit the indicia and the user identifier to the server. 9. The apparatus of claim 1 where the selection client is further operative to accept content contributions from a user. 10. The apparatus of claim 1 where the retrieval client is further operative to allow a user to manage any content contributed by them. 11. An apparatus for distributing content through one or more distributed information access points to a centralized access point of a user, comprising: at least one server operative to store one or more of: a) content, b) links to content, c) information about content, and d) information about users including information about which content a user has chosen; a centralized access point of a user accessible via a communications link and operative to provide the user with access to content chosen by or for the user; at least one distributed information access point accessible via a communications link and operative to implement one or more of: a) list one or more content objects, b) allow a user to choose content for addition to their centralized access point, and c) provide the user with logon access to their centralized access point; and an administrative interface in communication with the server and operative to create groupings of content into one or more distributed information access points; wherein a user is enabled with the capability to log on to their centralized access point from one or more distributed information access point(s) and access content chosen from one or more distributed information access point(s). 12. The apparatus of claim 11 wherein the distributed information access point comprises one or more of: a) a web page; b) a plurality of web pages; c) a portion of a web page; d) an email message; and e) a portion of an email message. 13. The apparatus of claim 11 wherein the distributed information access point is further operative to accept content contributions from a user. 14. The apparatus of claim 11 wherein the centralized access point is further operative to enable a user to manage any content contributed by them. 15. The apparatus of claim 11 wherein the administrative interface is further operative to manage content contributed by users. 16. A method of distributing content through distributed information access points, comprising: providing a database on a server accessible over a communication link capable of storing information about: a) content, and b) users; assembling content into one or more distributed information access points which are in communication with the database over the communication link; presenting one or more distributed information access points to one or more potential users at a visually perceptible location; selecting content from one or more of an entire range of distributed information access points for addition to a centralized access point of the particular user; and accessing the centralized access point of the particular user from one or more distributed information access points to gain access to the selected content. 17. The method of claim 16 wherein selecting and accessing are implemented by the particular user. 18. The method of claim 16 wherein the visually perceptible location comprises one or more of: a) an email message; b) a portion of an email message; c) a web page; and d) a portion of a web page. 19. The method of claim 16 wherein selecting content from one or more distributed information access points comprises using a device with a communications link to submit information to the database on the server. 20. The method of claim 19 wherein submitting information to the database on the server comprises submitting information about: (a) the selected content, and (b) the particular user.
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RELATED PATENT DATA This patent application is a continuation application of U.S. patent application Ser. No. 09/569,361, filed May 11, 2000, entitled “Apparatus for Distributing Information Over a Network-Based Environment, Method of Distributing Information to Users, and Method for Associating Content Objects With a Database Wherein the Content Objects are Accessible Over a Network Communication Medium by a User”, naming John R. Knapp and Edward K. E. Snyders as inventors, and which is now U.S. Pat. No.______, the disclosure of which is incorporated by reference herein. TECHNICAL FIELD This invention pertains to electronic commerce and business. More particularly, the present invention relates to aggregating, enhancing, and distributing content objects with customers over a network-based environment such as via the Internet or some other form of interactive network. BACKGROUND OF THE INVENTION The storage and retrieval of information has evolved from storing and retrieving information in textbooks and libraries, to storing and retrieving information from online networks such as the Internet. More particularly, the recent adoption and acceptance of online networks such as the Internet has led to a significant increase in the availability of information to the general public. Users frequently access information from the Internet using a personal computer (PC) and a modem. With such a computer, a user can search through the world's best libraries, connect into computer systems located anywhere on the planet, and read online magazines. Furthermore, users can shop for almost anything, located nearly anywhere in the world. However, this greatly expanded capability to retrieve information has led to a syndrome that can best be characterized as “sipping information from a fire hose”. As a result, users become overwhelmed and either fail to find the information they seek or they lose track of the information. As a result of losing track of the information, they cannot find it again at a later point in time. Several techniques have evolved in order to enable a user to collect desirable information from the Internet. However, each of these techniques falls far short of meeting the needs of information providers and information users. More recently, the World Wide Web (WWW) has become the main vehicle for delivering information over the Internet to users. The World Wide Web (WWW) is a network system that enables easy access to distributed documents over the Internet using a client/server architecture. The World Wide Web provides an Internet facility that links documents locally and remotely. A Web document, referred to as a Web page, includes links in a page that let users jump from page to page (hypertext links) whether the pages are stored on the same server or on servers around the world. These Web pages are accessed and read via a Web browser such as Netscape Navigator or Internet Explorer. A user often looks for information on the World Wide Web (WWW) during an online session using a Web search engine, such as AltaVista, Google, or Yahoo! In order to locate items of interest by way of hypertext links, many search engines gather information about content that is available on the Internet using Web crawlers. A Web crawler is a program that gathers information by following hypertext links that have been encountered by the program. The program sends a universal resource locator (URL), as well as document text, back to indexing software on the search engine for each encountered document. The indexing software extracts information from the documents. For example, words, document size and date of creation can be extracted by the indexing software. Such information has been organized into a database, typically based on the frequency of use of individual words present within a document. Accordingly, a keyword search that is implemented by a user with the search engine results in a database being searched, and a search result being generated without actually going directly to the World Wide Web (WWW). The search engine then generates a results page having hypertext links to the Web pages that were located in the database. A user then merely clicks on the link in order to go to the corresponding Web page. However, the World Wide Web (WWW) has merely increased the accessibility of large amounts of information to Internet users. There is a need, therefore, to provide improvements in the way demand for information is identified, content is generated in response to a defined demand, and the way in which users access desired information. SUMMARY OF THE INVENTION A system and method are provided to document and quantify demand for particular information that is a requested by an individual user by sampling a worldwide user community by way of a networked system. Accordingly, user demand is aggregated in order to learn what information is desired by people. The aggregated demand is then used to compel a contributor to contribute information such as content objects. Additionally, information in the form of content objects available on the networked system is enhanced by way of an approval process, by ranking content, and by categorizing content. Furthermore, content is distributed to users in several manners: by way of a primary Web site, and by way of predetermined but dynamic groups of aggregated content objects which are made available via banners and/or tokens. According to one aspect, an apparatus is provided for distributing information over a network-based environment. The apparatus includes a first client, a server, and a second client. The server communicates with the first client via a communication link and includes a database operative to store indicia associated with at least one content object and user identifiers. The second client communicates with the server over a communication link. The second client is remote from the first client and is operative to submit indicia and a user identifier to the server. In response to submission of the indicia and the user identifier, at least one of: (a) a content object, and (b) a link to the content object are received into a personalized access point of the server. The user can access the personalized access point of the server with the first client. According to another aspect, a method is provided for distributing information to users. The method includes: providing a database capable of being associated with content objects that are accessible over a communication medium by a user at a client; associating at least one content object with a distribution mechanism; requesting a desired one of the at least one content object; and receiving the requested content object into a network-based personalized access point. According to yet another aspect, a method is provided for associating content objects with a database wherein the content objects are accessible over a network communication medium by a user. The method includes: receiving a suggestion for a new content object for addition to the database; approving the suggested content object; generating a list of information users desiring the approved content object; compelling an information provider to provide the desired content object based at least in part on demand identified by the generated list; and making the generated content object available to the database. According to even another aspect, a method is provided for distributing information to users. The method includes: providing a database on a server at a first location operative to store indicators that are associated with content objects, wherein the content objects are accessible over a communication link; presenting an indicator at a visually perceptible location to a user; while at a second location, submitting the indicator and a user identifier to the server at the first location; and in response to submitting the indicator and the user identifier, subscribing to one of: (a) a content object associated with the link, and (b) a link to the content object; and receiving one of the content object and the link into a personalized access point; wherein the personalized access point is viewable at a third location provided in communication with the web-based server over a communication link. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described below with reference to the following accompanying drawings. FIG. 1 is a block diagram overview of a basic system configuration of an exemplary system for aggregating, organizing, ranking, and distributing content objects between information providers and information users over a network-based environment according to one embodiment of the present invention. FIG. 2 is a process flow diagram showing part of the logic processing for aggregating and distributing content objects. FIG. 3 is second process flow diagram showing part of the logic processing for enhancing aggregated content objects by assessing demand for content and compelling content providers to contribute content objects to the network. FIG. 4 is a third process flow diagram showing part of the logic processing for distributing aggregated content objects to users via a wireless Web appliance and product associated indicia that identify a set of predefined, yet dynamic aggregated content objects. FIG. 5 is a diagram showing the assembly of FIGS. 6A and 6B. FIGS. 6A and 6B together form a diagram of a screen display for a HowZone.com home page comprising a point of entry into a HowZone.com web site having a dynamically generated category network. FIG. 7 is a diagram of a screen display for a Web page illustrating a “Business” category page that is at a down-tree location from the screen display of FIGS. 6A and 6B. FIG. 8 is a diagram of a screen display for a personal HowZone for a new user prior to selecting any content objects. FIG. 9 is a diagram of a screen display for a content detail page having a link usable to add the described content object to a user's personal HowZone. FIG. 10 is a diagram of a screen display for the personal HowZone of FIG. 8, after the addition of a content object to the user's personal HowZone. FIG. 11 is a diagram of a screen display for a hosted, or distributed, HowZone which is located on another Web site, and showing an alternate method for displaying HowZone content objects. FIG. 12 is a diagram of a screen display for the HowZone content detail page which is generated by selecting an item from the scrolling list of FIG. 11, and containing a link that enables a user to add the selected item to their personal HowZone. FIG. 13 is a diagram of a screen display for the personal HowZone of FIG. 10 showing the aggregation of content objects within the personal HowZone after selecting the link of FIG. 12 which enables adding the selected item to the personal HowZone. FIG. 14 is a diagram of a screen display showing one exemplary personal HowZone for a specific user containing a listing of all content objects previously selected by such user and showing a pop-up menu selected by a user for enabling the assignment of a ranking to a content object. FIG. 15 is a diagram of the screen display of FIG. 14, but showing a user selecting the send ratings button in order to send ratings of the user's content objects to the HowZone server, or system. FIG. 16 is a diagram of the screen display of FIG. 7 illustrating a page from the content object listing and further illustrating the number of users, rating and cost for each content object. FIG. 17 is a diagram of a screen display for a content detail page for a single content object of FIG. 16. FIG. 18 is a diagram of a screen display used by HowZone administrators to add a new category to the category listing in the screen displays of FIGS. 7 and 16. FIG. 19 is a diagram of a screen display illustrating the basic elements of an exemplary category network page for an “automobiles” category with a “top” parent category as viewed by a user. FIG. 20 is a diagram of a dynamically generated category network corresponding with the screen displays of FIGS. 7 and 16, and illustrating the case where a dynamic category network includes two categories having multiple parents. FIG. 21 is a diagram of a screen display for a “business” category page displaying “include files” for a header, a footer, and a commerce banner. FIG. 22 is a diagram of the screen display of FIG. 21 where the “business” category page includes a different commerce banner caused by using a different “include” file for the commerce banner. FIG. 23 is a diagram of a screen display similar to the screen display of FIG. 22, but wherein an original entry point is provided to the corresponding screen display, thereby illustrating a “multiple-point-of-entry” capability of the HowZone network. FIG. 24 is a diagram of a screen display showing a link, found on each category page, and used to collect suggestions from users. FIG. 25 is a diagram of a screen display for a user request form. FIG. 26 is a diagram of a screen display for a HowZone administrative page used to approve user requests for new content. FIG. 27 is a diagram of a screen display showing a freshly requested and approved content object provided within a HowZone category network. FIG. 28 is a diagram of a screen display showing a content detail page for a content object which is not yet available on the HowZone system, and further showing information about the content object, and providing a link which enables a user to join a waitlist. FIG. 29 is a diagram of a screen display showing a page where a user joins the waitlist. FIG. 30 is a diagram of a screen display for a content detail page having a waitlist and showing a potential contributor that they can earn money for making this contribution. FIG. 31 is a diagram showing the assembly of FIGS. 32A through 32C. FIGS. 32A through 32C together form a diagram of a screen display providing a form usable by an expert to indicate their interest in making a specific contribution to the HowZone system. FIG. 33 is a diagram showing the assembly of FIGS. 34A and 34B. FIGS. 34A and 34B together form a diagram of a screen display for a HowZone.com administrative page that enables approval of a potential contributor to the HowZone system. FIG. 35 is a diagram of a screen display for a “business” category entry present within a category network and below a “top” category entry. FIG. 36 is a diagram of a screen display similar to that depicted in FIGS. 34A and 34B, but illustrating a “multiple-point-of-entry” category tree capability wherein the parent category “top” does not appear above the category “business”. FIG. 37 is a diagram of a screen display illustrating an alternative vehicle for distributing content comprising a content object window which will be embedded within pages of other web sites. FIG. 38 is a simplified schematic diagram of a point-of-purchase customer at a bricks and mortar store, and further showing merchandise containing a HowZone.com content distribution token having product-associated indicia, enabling a customer to remotely select aggregated content objects for their personal HowZone via a wireless web appliance. FIG. 39 is an enlarged partial view of the wireless web appliance of FIG. 38 further showing the user interface. FIG. 40 is a diagram of a screen display for a user's personal HowZone, and showing a user graphically selecting a contributions link. FIG. 41 is a diagram showing the assembly of FIGS. 42A and 42B. FIGS. 42A and 42B together form a diagram of a screen display showing an exemplary list of contributions made by a user. FIG. 43 is a diagram of a screen display for a content builder for a content object type of link. FIG. 44 is a diagram of a screen display for a user's personal HowZone and including a recently approved content object which has appeared within a HowZone.com category network, and selected by the user for addition to their personal HowZone. FIG. 45 is a diagram of a screen display for a content object that has been selected by user from within the user's personal HowZone, and which is presented within a separate window from the user's personal HowZone. FIG. 46 is a diagram of a screen display of a content builder for a content object type of tutorial. FIG. 47 is a diagram of a screen display illustrating a user selecting a file from the user's hard disk in order to upload using a HowZone.com content builder, wherein the uploaded files are stored on a HowZone.com web server. FIG. 48 is a diagram of a screen display for a completed tutorial page with graphics being uploaded to HowZone.com. FIG. 49 is a diagram of a screen display showing a content builder having one page, and further showing the contributor adding a second page. FIG. 50 is a diagram showing the assembly of FIGS. 51A and 51B. FIGS. 51A and 51B together form a diagram of a screen display showing a completed tutorial being saved into the HowZone.com system. FIG. 52 is a diagram of a screen display for an administrative page usable by HowZone.com personnel, or staff, to approve a content object. FIG. 53 is a diagram of a screen display for a content object type of tutorial illustrating a HowZone.com navigation system extending across a top-most portion of the screen display. FIG. 54 is a diagram of a screen display illustrating a dynamically generated pop-up navigation tool present within the HowZone.com tutorial delivery system. FIG. 55 is a diagram showing the assembly of FIGS. 56A and 56B. FIGS. 56A and 56B together form a diagram of a screen display illustrating another page which is just been selected using the pop-up navigation tool of FIG. 54. FIG. 57 is a diagram of a screen display showing a dedicated discussion forum that is provided with each tutorial, wherein users can discuss things that the users are learning. FIG. 58 is a diagram of a screen display showing that each tutorial has a dedicated student note taking function, where users can keep personal notes similar to margin notes a person might write in the margin of a textbook. FIG. 59 is a diagram of a screen display showing that tutorials can contain links to external Web pages, and that access to such pages is implemented via the same pop-up navigational tool present within the HowZone.com system. FIG. 60 is a diagram showing the assembly of FIGS. 61A and 61B. FIGS. 61A and 61B together form a diagram of a screen display showing an external web page appearing within the HowZone.com tutorial display and navigation system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8). I. Overview A system and a method are described for aggregating, enhancing, and distributing content objects with users over a network-based environment. According to one implementation, the users are customers and the content objects are provided by experts who desire to share information with such customers. First, a determination is made as to specific information that is desired by individuals. Secondly, a provider of information is encouraged to contribute information that matches the information that has been determined to be desired by individuals. Furthermore, contributors are given the ability to contribute information by uploading content and/or by distributing links to content that is available over a network system. Contributed information is distributed to individuals by making such information perceptible to individuals at distributed information access points. One technique entails making the information visually perceptible to individuals. One suitable distributed information access point is provided by a token placed on a product, product packaging, a sign or an advertisement. Other distributed information access points comprise viewer perceptible screen displays on client computers or wireless web appliances. Distributed information access points enable placement of visually perceptible information in front of individuals, with distribution of such information being centralized through the network-based system. One form of a distributed information access point comprises a rich media banner ad. Another form of a distributed information access point involves co-branding information by placing a visually perceptible medium on a third-party web site where it can be viewed by an individual. In order to organize links and/or uploaded content so that it can be viewed by individuals, a dynamically generated category network is implemented to sort and distribute information. By using a category network, portions of the network can be utilized to co-brand specific information using distributed access points. A web site provided by Applicant's invention enables users to select links and/or content objects from the dynamically generated category network, placing such selections into a personalized access point. One form of such personalized access point comprises a personal web page present on Applicant's web site. Yet another feature described below entails users ranking selected information, with the rankings giving indications that help other users select desirable information from Applicant's web site. In order to learn more information about the specific information that individuals desire, a system and a method are provided to document and quantify demand for particular information that has been requested by an individual user. The quantification and documentation is carried out by sampling a world-wide user community which accesses Applicant's web site within a network environment and through use of a network system. Such a system and method use a user comment form, a centralized editorial and approval function, and a “Join the Waitlist” function. All of these functions are accessed through a distributed stand-alone access point, as will be described below with reference to the following figures and embodiments. In operation, a user requests information, Applicant's web site (via a system administrator/staff) checks the requested information, then posts the request in public where other users can join a waiting list. The waiting list, or waitlist, publicly displays a proven demand to potential contributors of information. In order to entice a potential contributor to contribute information that has been documented as being desired by specific individuals, a system and method are provided to use documented and quantified world-wide user demand for particular information in order to compel an individual and/or organization to contribute the particular information using a network system. In other words, a perspective contributor is shown a “waiting list” of users who desire particular information. The system and method allow anyone to make a contribution by uploading web pages with graphics to be stored on Applicant's web site and system. The system and method then present the information to individuals who potentially desire such information. Additionally, users are allowed to provide links to other pages, and to add such links to Applicants' web site. The system and method uses distributed information access points to more effectively reach a world-wide user community. User convenience is increased by providing a greater number of access points to information that is demographically selected to be more highly desired by users at that particular distribution point. The system and method uses a host web site that is connected to a world-wide network system in order to provide space for the distributed access points. The system and method also uses a centralized server system that is connected to a world-wide network system in order to provide the information and functionality found within the distributed access points. However, any type of network environment can be used. Applicant's system creates subsets of information, and loads the subsets of information into a file which can be included in a web page. A server on Applicant's web site then drives the information and functionality located in such file. The use of a dynamically generated category network supports co-branding, wherein a portion of a category network is presented on a third-party web site. Information contained within distributed information access points is provided to a world-wide user community through the use of such dynamically generated category network and within a network system. Personal web pages on Applicant's web site provide a system and method that allows any individual user within the world-wide user community to select information from any distributed stand-alone access point that is capable of being accessed within a network system. The information selected by any individual user is added to their own personalized, centralized consumption access point that is accessed with a network system. In one form, the personalized access point comprises a personal web site. Typically, such access is carried out using a client, such as a client computer. Accordingly, a user's personal web page keeps all of their collected information in one place, on a server of Applicant's web site. Enabling users to rank selected information and drive content ranking simplifies the content object selection process of other users. Accordingly, contributors will be encouraged to do a good job so that they receive a relatively high ranking, and are listed higher within a listing on Applicant's web site that ranks orders from contributors based upon how highly they are ranked by previous users. As will be described below in greater detail, staff and administrators at Applicant's web site are able to manage content categories, manage suggestions for content objects, manage content contributors, manage content objects, co-brand categories, and place commerce on content categories. Accordingly, the operation of Applicant's web site, as well as related web properties, is highly automated and is browser based. Accordingly, such administrative implementation scales, or can be increased in capacity or size, without limitation. Content categories provide an organizational framework for Applicant's web site. The categories can be added, moved, hidden, deleted and have their appearance modified using a web browser by way of a dial-up or other Internet connection. Accordingly, a user does not need to be trained with HTML programming in order to carry out such tasks. In order to manage suggestions for content objects, site visitors make suggestions which staff at Applicant's web site review and approve. The process consists of displaying an administrative page, as will be discussed below in greater detail. The administrative page contains suggestions, and the staff review and optimally reword such suggestions, then approve the content object for posting within one or more categories. This task is also performed using a web browser via an Internet connection. For purposes of managing content contributors, content contributors are the organizations and individuals who contribute content objects to Applicant's web site. It is required that the content contributors be approved before they are allowed to make contributions to Applicant's web site. The process comprises displaying an administrative page that shows qualifications submitted by the contributors, reviewing the contributors, and approving the contributors. This task is also performed using a web browser and an Internet connection. For purposes of managing content objects, content objects are assigned to one or more categories, with the content objects appearing within the category network for review, selection and use by site visitors. The content objects can be added, moved, edited, hidden or deleted using a web browser on an Internet connection. With respect to co-branding of content categories, content categories are dynamically generated, database-driven web pages whose appearance is driven by separate files. Once these files have been assigned to a content category, the content category takes on the respective appearance assigned by such files. Based on input from sales and marketing personnel, staff at Applicant's web site will assign such files to these categories using a web browser on an Internet connection. According to one implementation, such files can be resident on a client's server, and can be maintained by the client. Alternately, such files can be uploaded and stored within the Applicant's system or another web server. When placing commerce on content categories, content categories support commerce by assigning separate files which appear on the content categories. Once these commerce files have been assigned to respective content categories, commerce carried out within these categories is made visible to site visitors. Based on input from customers and sales and marketing personnel, staff at Applicant's web site will assign these commerce files to respective categories using a web browser and an Internet connection. The commerce files can also reside on a client's server, and can be maintained by such client. II. Implementation Details Reference will now be made to a preferred embodiment of Applicant's invention. One exemplary implementation is described below and depicted with reference to the drawings comprising a system and method for aggregating demand for information, compelling contributors to contribute content that satiates the demand, aggregating content so that users can easily access the aggregated content, enhancing the existing content, and distributing the content to users over a network system. While the invention is described by way of a preferred embodiment, it is understood that the description is not intended to limit the invention to this embodiment, but is intended to cover alternatives, equivalents, and modifications such as are included within the scope of the appended claims. In an effort to prevent obscuring the invention at hand, only details germane to implementing the invention will be described in great detail, with presently understood peripheral details being incorporated by reference, as needed, as being presently understood in the art. A. Client/Server Exemplary Architecture FIG. 1 illustrates a preferred embodiment of Applicant's invention wherein a basic system configuration is provided for aggregating demand, enhancing content, and distributing content objects with customers, and is identified with reference numeral 100. System 100 is usable with an online network 102 within a network-based environment in the form of a networked computer system 104. According to one construction, network 102 is provided by the Internet 106, and more particularly, the World Wide Web (WWW) 108. According to one construction, network 102 is a client/server network having one or more clients, such as clients 110 and 112, and a web server 114. According to one construction, client 110 comprises a client computer 111, client 112 comprises a client wireless system 113, and web server 114 comprises a web server computer 115. One suitable wireless system 113 comprises a cellular system. For purposes of this disclosure, the term “client” is understood to include a workstation or a computer, such as a personal computer, a hand-held computer, or a portable electronic device such as a wireless web appliance having computing capabilities, and provided within a client/server environment. A “client” is also intended to include a device present in a network, such as the Internet, that includes a software program for enabling a user to interact with the network and send and receive files, electronic mail, and/or data. Even furthermore, “client” is intended to include, in a network environment, a computer or workstation connected to the network and the server and including web-enabled appliances, or any other device having processing capabilities. It is further understood that a “client” can include a software component such as a web browser. Also for purposes of this disclosure, the term “server” is understood to include one or more computers located at one or more physical locations and having a hardware component that serves code and data to the World Wide Web (WWW), and includes a web server computer including a software program that receives, manages, and responds to requests for documents and files. For example, such request can be structured using Hypertext Transfer Protocol (HTTP), wherein the requests are processed and then sent back to the client. Furthermore, for the purposes of this disclosure, the term “server” is understood to include computers located at one or more physical locations. These computers are understood to have a hardware component that serves data from a relational database as well as computers which provide the logic processing to access database information that is used to dynamically generate the code and data served to the World Wide Web (WWW) by the web server computer. As shown in FIG. 1, it is understood that one form of online network 102 comprises a networked computer system 104. Networked computer system 104 includes a web server computer 115 as well as client computer 111 and client wireless system 113. More particularly, client computer 111 includes a web browser 120, including a web document 122. According to one construction, web browser 120 comprises a software program configured to enable a user to access files from any computer that is interconnected with the Internet 106. Web document 122 comprises an electronic page or document that is visually perceptible by a user as an image on a visually perceptible interface for a client, such as a client computer. Similarly, client wireless system 113 includes web browser 120 and web document 122, wherein web browser 120 and web document 122 are provided within a wireless web appliance 126. Wireless web appliance 126 remotely communicates via a wireless network 124 and a communication medium, or link, 117 via the Internet 106 with online network 102. Furthermore, web server 114 communicates with Internet 106 via communication medium, or link, 118. With respect to client computer 111 and client wireless system 113, two variations of a client 110 and 112 are illustrated which are suitable for implementing the features of Applicant's invention. For purposes of explanation, client 110 will be used for the following discussion. More particularly, web server computer 115 comprises a hardware component capable of serving code and data to the World Wide Web (WWW) 108. Web server computer 115 enables the implementation of web server 114, and includes a software program that receives, manages, and responds to client requests for web documents and files. Accordingly, web server 114 includes system 100 for aggregating, enhancing, and distributing content objects that are consumed by users over a network-based environment. Web server 114 includes a web site 128 upon which system 100 is implemented, and is viewable by a user with a web browser 120 at clients 110 and 112, respectively. Web site 128 includes one or more web pages 130 and a database 132, in which links of searchable content objects are catalogued, and from which such links and/or content objects can be retrieved by a user at client 110. As shown in FIG. 1, web site 128 includes one or more web pages 130 and a database 132. Each web page 130 includes a unit of information provided in the form of a data unit that includes text and/or graphics, audio, video, and/or other dynamic media. Client 110 and/or 112 can be used by a user in order to present such a data unit on a screen to a user, such as an individual searching for content objects identified by links which are retrieved from database 132. For purposes of this disclosure, individual web pages can be active and include “hot buttons”, or “clickable icons”, or “links” which will also be referred to hereafter as “triggers”. “Triggers” enable the launching of a simple application-software program and/or access to linked pages. It is understood that database 132 includes a collection of inter-related and/or non-related data including links that are stored together on web server computer 115, and which can include individual web sites that are accessible by a user via clients 110 and/or 112. As also shown in FIG. 1, it is understood that a client computer 110 or 112 forms a general purpose machine capable of processing data by way of a set of instructions that is stored in a data storage device, such as memory. For the case where a computer is involved, the computer and peripheral components include hardware on which one or more software programs are implemented. Such hardware can include a processor or microprocessor; a hard disk drive; interface devices such as a display screen, a keyboard and a tactile input device; and other associated components that are readily understood in the art. Furthermore, it is understood that web server computer 115 can include hardware such as one or more processors, or microprocessors; one or more data storage devices, such as a hard disk drive (HDD); memory, such as random access memory (RAM); and interface devices, such as a display screen, keyboard and/or a tactile input device. As shown in FIG. 1, a visually perceptible medium 133, such as a token 134, can be applied directly on a product or on provided packaging, or printed on advertising materials, brochures, flyers or other notices. According to one construction, medium 133 comprises token 134, which is in the form of an adhesive applique or sticker on which an indicator 136 comprising indicia 135 is printed. In one form, indicia 135 includes an identification number that identifies a specific set of content objects, a single content object, or a link to one or more content objects. A user identifier 138, such as a user identification element, is presented by a user along with indicia 135 which has been retrieved by the user from token 134 at a visually perceptible location for submission to a client 110 or 112. As utilized herein, the term “indicator” refers to anything that indicates, points out, shows or reveals something. Furthermore, the term “indicia” refers to an indicator such as an identifying marking or statement used to single out one thing from another thing, or to serve as a directional guide that shows the location, nature, quality or existence of something, such as an item. According to FIG. 1, client computer 111 communicates with Internet 106 by way of a communication medium, or link, 116, such as an Integrated Services Digital Network (ISDN) telecommunications line, or a landline telephone line. ISDN is an international telecommunications standard for transmitting voice, video and data over digital telephone lines. However, it is understood that communication medium 116 can also include an analog telephone line, or any other communication medium or communication link capable of interconnecting a client 110 with an online network 102. According to the implementation illustrated by client wireless system 113, communication medium 117 comprises a wireless communication link provided between a wireless network 124, such as a cellular network, and the Internet 106. One presently commercially available implementation for client wireless system 113 is provided by Sprint PCS Wireless Web, a wireless internet solution comprising a client wireless system 113 presently available from Sprint PCS, P.O. Box 140, London, Ky. 40744-7960, with further information available on the World Wide Web (WWW) at http://www.sprintpcs.com/wireless/index.html. Such client wireless system 113 includes a wireless web appliance 126 comprising a wireless telephone, including a wireless web browser 120 on which web documents 122 are visually perceptible and viewable by a user remotely, and in a wireless manner with web server computer 115. Accordingly, such solution includes a wireless web connection that is provided between wireless web appliance 126 and wireless network 124. It is further understood that web browser 120 comprises a compact web browser that is capable of being implemented on a wireless web-enabled telephone. However, it is understood that wireless web appliance 126 can take the form of a laptop computer, a pen computer, a hand-held computer, an electronic organizer, or any other device having wireless connectivity and a web browser capable of being interconnected with the Internet 106. According to another construction, it is envisioned that client wireless system 113 utilizes a Wireless Application Protocol (WAP). WAP comprises a carrier-independent, transaction-oriented protocol provided for wireless data networks, and designed for substantially all types of networks. One version of WAP has been initially implemented on GSM networks. Suitable wireless telephones, such as digital wireless telephones, are presently available from Nokia Americas, of Irving, Tex.; Erickson North America, of Richardson, Tex.; and Motorola, Inc., of Schaumburg, Ill., which are capable of being utilized with WAP Version 1.1, which was released in June 1999. These web telephones include relatively large viewable screens and a scrolling mouse such that a visually interactive computer telephony system is provided to a user that enables remote and wireless connectivity via web browser 120 with web sites such as web site 128 on web server computer 115. However, it is understood that other wireless technologies can also be used. As illustrated in FIG. 1, a visually perceptible medium 133 is presented for visual identification to a user of client 110 or client 112. Where a user visually perceives medium 133 at client 110, typically medium 133 comprises a portion of a screen display which is displayed to a user on a monitor of client computer 111 by way of web browser 120. As will be described below with reference to FIGS. 5-59, there exist a number of embodiments for presenting medium 133 in a visually perceptible manner to a user at client 110. According to another implementation, medium 133 is presented to a user in a visually perceptible manner. The user visually identifies indicia 135, then logs into web site 128 via Internet 106 and wireless web appliance 126. The user then submits an identification number 136, comprising indicia 135, and their user identifier 138 to web server computer 115 such that content objects associated with identification number 136 are made available to this user via a network-based personalized access point within web site 128, as will be discussed below in greater detail. It is further understood that such selection of content objects may be carried out on behalf of the User by another user or automated selection system as directed by the user. For example, the selection of content objects may be carried out by a clerk at a cash register within a store on behalf of a customer. Similarly, the selection of content objects can be carried out by a salesperson at a sales booth within a trade show on behalf of a user wherein the user carries a smart card that identifies the user and the user's personal web page, and the salesperson swipes the smart card into a card reader in order to retrieve the user's identification. An even further example contemplates such selection of content objects being carried out when a user purchases a product at a web site, and the web site checkout page requires an inputting of personal user and payment information, and includes a checkbox that directs the transfer of information into the user's personal web page when the user checks the box. According to such implementation, a user selects indicia 135 at one location using appliance 126, and consumes information that corresponds with indicia 135 at another location. For example, a user submits indicia 135 via web appliance 126, then receives content objects and/or links to content objects and consumes content objects corresponding with indicia 135 when they return home from the store using their home-based personal computer. The content objects can be consumed directly by viewing received content, or by accessing content objects using links. Accordingly, client wireless system 113 comprises a mobile internet service that allows access by way of links which are retrieved from web site 128 to content objects present within online network 102. The collection of such content objects, the provision of such content objects, and the availability with which such content objects are aggregated, ranked, distributed, dispersed, and received by the user falls within the novel aspects of Applicant's invention, as described below with reference to FIGS. 2-61. Accordingly, system 10 of FIG. 1 enables the aggregation of content objects according to the process flow diagram of FIG. 2, and as detailed in FIGS. 5-61. Furthermore, system 10 enables the enhancement of aggregated content objects by assessing demand for content and compelling content providers to contribute content objects to the network, as described below with reference to the process flow diagram of FIG. 3, and further in reference to FIGS. 5-61. Even furthermore, system 10 illustrates one technique for distributing aggregated content objects to users by way of a wireless web appliance, and by using product-associated indicia that identify a set of predefined, yet dynamic aggregated content objects, as shown in the process flow diagram of FIG. 4 and in reference to FIGS. 5-61. It is understood that system 10 aggregates content objects in a number of different ways. FIG. 2 illustrates one implementation for aggregating content objects, as will be described below with reference to FIG. 2. System 10 also enhances aggregated content objects by assessing the demand for content and compelling content providers to contribute content objects to the network. FIG. 3 illustrates one exemplary implementation for enhancing aggregated content objects in such manner. System 10 also distributes aggregated content objects to users by way of a wireless web appliance and product-associated indicia that identify a set of predefined, yet dynamic aggregated content objects. FIG. 4 illustrates one exemplary implementation for distributing such aggregated content objects to users. However, it is understood, with respect to the implementations depicted in FIGS. 2-4, that other implementations are readily known for aggregating, enhancing and distributing content objects to users, as will be described below with reference to screen displays 5-61. Furthermore, it is understood that alternative implementations will be readily understood with reference to the following general discussion relating to the novel aspects of Applicant's invention. In order to better understand the claimed aspects of Applicant's invention, a detailed example is presented below for aggregating content objects, enhancing aggregated content objects, and distributing aggregated content objects with respect to FIGS. 2-4, respectively. FIG. 2 forms a process flow diagram showing the logic processing for aggregating content objects using system 10 (of FIG. 1). More particularly, FIG. 2 illustrates logic processing used to aggregate content objects. As shown in FIG. 2, a logic flow diagram illustrates the steps implemented by the system of Applicant's invention when aggregating content objects. In Step “S1”, a web site on a web server provides a database capable of being associated with content objects that are accessible over a communication medium. One such database comprises database 132 of web site 128, accessible over one or more of communication links 116, 117, and 118 (of FIG. 1). After performing Step “S1”, the process proceeds to Step “S2”. In Step “S2”, the system associates one or more content objects with a distribution mechanism. One suitable distribution mechanism is provided by a visually perceptible medium 133 in the form of token 134 having indicia 135 such as identification number 136. It is understood that identification number 136 can take a number of forms, including numerical code, alpha-numeric code, alpha code, universal product code (UPC), electronic product code (EPC), or bar code. Another form of distribution mechanism is the utilization of any other form of visually perceptible medium 133, such as presenting an icon, window, banner, or electronic token over a visually perceptible interface to a user, such as a display of a client computer 111 (of FIG. 2). After performing Step “S2”, the process proceeds to Step “S3”. In Step “S3”, an individual requests a desired content object for personal consumption from distributed information access points such as a visually perceptible medium. Various forms of a visually perceptible medium are envisioned, including one or more objects and/or links located within a web page, a portion of a co-branded web page, a banner, a button, a clickable icon, a clickable graphic, or a hypertext link located on someone else's web page, a content object token, and/or a networked device such as a networked cash register, bar code scanner or electronic product code reader. After performing Step “S3”, the process proceeds to Step “S4”. In Step “S4”, requested content objects or links to content objects are received into a network-based personalized access point. One such network-based personalized access point comprises a personal web page located within a web site 128 of a web server computer 115 in system 10 (of FIG. 1). After performing Step “S4”, the process proceeds to Step “S5”. In Step “S5”, the requested content objects are dynamically modified to provide subscribing users with access to current or modified information within their personalized access point. After performing Step “S5”, the aggregating of content objects of Applicant's invention terminates. It is understood that FIG. 1 illustrates one aspect of Applicant's invention. However, it is also understood that Applicant's invention can be applied to any device that is capable of connecting to a network-based environment such as intranets, or any interconnected arrangement of devices capable of aggregating and distributing information to users. FIG. 3 forms a process flow diagram showing the logic processing for enhancing aggregated content objects by assessing demand for content and compelling content providers to contribute content objects to a network. In Step “SS1”, a server of Applicant's web site receives a suggestion from a user for a new content object for addition to a database. For example, database 132 of web site 128 can be accessed by a user via client 110 in order to suggest a new content object which is to be added to database 132 (of FIG. 1). Optionally, client 112 can be used to access database 132 where full web browser capabilities are provided on the corresponding wireless web appliance. After performing Step “SS1”, the process proceeds to Step “SS2”. In Step “SS2”, a third party, such as a provider and/or web site administrator for web site 128, approves the suggested content object. For example, a web administrator can review the suggested new content object of Step “SS1”, then approve the suggested content object, thereby presenting the suggested content object onto a web page 130 of web site 128 (of FIG. 1). After performing Step “SS2”, the process proceeds to Step “SS3”. In Step “SS3”, a list of information users desiring the content object, or a waitlist, is generated or created which includes information users that desire the suggested or approved content object. After performing Step “SS3”, the process proceeds to Step “SS4”. In Step “SS4”, an information provider is compelled to generate the desired content object which was suggested, approved and placed onto a waitlist, based at least in part on demand that is identified by the generated waitlist. After performing Step “SS4”, the process proceeds to Step “SS5”. In Step “SS5”, the generated content object is contributed, or made available, to the database. For example, a generated content object is consequently added to database 132 of web site 128 (of FIG. 1). After performing Step “SS5”, the process proceeds to Step “SS6”. In Step “SS6”, users placed on waitlists are notified of the availability of a requested content object. Accordingly, users who have previously joined a waiting list, or waitlist, are notified that a content object that they are waiting for is now available. Such users can then gain access to the content object. For example, one notification technique involves notifying the users by e-mail where an e-mail message contains a clickable link that allows a user to add the content object to their personal web page by clicking on the link. After performing Step “SS6”, the process is terminated. As shown in FIG. 4, a logic flow diagram illustrates the steps implemented by the system of Applicant's invention showing part of the logic processing for distributing aggregated content objects to users by way of a wireless web appliance and product-associated indicia that identify a set of predefined, yet dynamic aggregated content objects. In Step “SSS1”, a database is provided on a server at a first location. The database is operative to store indicators that are associated with the content objects. The content objects are accessible over a communication link. After performing Step “SSS1”, the proceeds to Step “SSS2”. In Step “SSS2”, an individual or user observes a visually perceptible medium in the form of a token upon which an indicator such as visually perceptible indicia is/are provided or presented to the individual/user. The product-associated indicia identify a set of predefined, yet dynamic aggregated content objects. The dynamic feature of the aggregated content objects relates to the ability of a content provider and/or system administrator to periodically change or update components of the set of predefined aggregated content objects that are identified by the product-associated indicia. After performing Step “SSS2”, the process proceeds to Step “SSS3”. In Step “SSS3”, a network user subscribes to content objects by submitting the indicator as well as user information, or identifier, to a web page. For example, a user submits indicia 135 in the form of an identification number 136 and user identifier 138 to web page 130 (of FIG. 1). According to one implementation, user identifier 138 comprises a user-assigned alpha-numeric identification which identifies the particular user so that a content object corresponding with identification number 136 can be deposited within such user's personal web page at Applicant's web site. The indicia are understood to identify a set of predefined, yet dynamic aggregated content objects to which the user wishes to subscribe. After performing Step “SSS3”, the process proceeds to Step “SSS4”. In Step “SSS4”, a subscriber, or user who has subscribed to content objects, receives the content objects and/or links to the content objects into a network-based personalized access point. For example, a user of client 110 or 112 subscribes to content objects by submitting indicia and user information to web page 130. One or more aggregated content objects that are identified by the indicia are received within a personal web page of web site 128 which forms a network-based personalized access point which is accessible by the user at client 110 and/or 112. Exemplary details are provided below with reference to FIG. 15. After performing Step “SSS4”, the process terminates. It is understood that FIGS. 2-4 each illustrate a particular aspect of Applicant's invention. However, it is also understood that Applicant's invention can be applied to other systems and methods for aggregating content objects, enhancing aggregated content objects, and distributing aggregated content objects to users by way of a network. FIGS. 5-61 illustrate by example graphical user interface features as seen from a client by a user or system administrator and comprising hypertext mark-up language (HTML), front end user tools that are provided as an extension to a web server 114, and software resident in memory on web server computer 115 (of FIG. 1). Such user interface features are implemented on a web server computer and are presented below to illustrate one implementation of Applicant's system and method for aggregating, enhancing, and distributing content objects with customers over a network-based environment. According to one implementation, the network-based environment comprises an online network which is shown as the Internet, and more particularly, as the World Wide Web (WWW). As shown in FIGS. 5-61, a graphical user interface on a client such as a display screen is used to display individual web pages in the form of screen displays, or screens. Each screen contains icons, or triggers, that may be clicked on in order to select different services and/or to navigate between the web pages. FIGS. 5-19, 21-37, and 40-61 each form diagrams of exemplary screen displays that the computerized system of Applicant's invention provides to a user during various steps when navigating through the content object web site. For purposes of this disclosure, it is understood that a screen displays at least a portion of a web page, and that the screen includes a window which is a predefined part of virtual space. Accordingly, a screen can include selection buttons, pop-up menus, pull-down menus, icons, links, buttons, scrolling lists, data entry fields, embedded content objects, radio buttons, check boxes, and other usable and selectable items capable of being configured or selected with a cursor using a tactile input device such as a pointer, a mouse, and/or a keyboard or button. It is further understood that in dynamically generated, database driven web sites such as these that web pages are created, upon demand, from data stored in databases within the Applicant's web site and system and on other web servers elsewhere on the World Wide Web (WWW). Applicant's system and method are implemented by way of Applicant's web site, HowZone.com, corresponding to web site 128 of online network 102 (of FIG. 1). One exemplary web site address is http://www.HowZone.com. Individual, private web ages within such web site are only accessible by registered and assigned users who want to aggregate, enhance, and/or distribute content objects within the system of Applicant's invention and on Applicant's web site. For example, the screen displays of FIGS. 13 and 14 illustrate personal user web pages, or “personal HowZones”, where a user can access links to content objects and/or content objects which have been collected therein using Applicant's web site. Each user's “personal HowZone” is accessed by an opening security screen (not shown) which can be presented to a user who is accessing Applicant's web site or presented to a user via other distributed information access points managed by Applicant's system. Such an opening security screen to a user's “personal HowZone” prevents the general public from accessing information which has been provided to that user's personal HowZone, or personal web page. Furthermore, the aggregating of content objects encompasses the adding of particular links to content objects. Additionally, such aggregation encompasses the provision of content within content objects to the personal web site by a user and/or an authorized party such as a system administrator on Applicant's HowZone.com web site. An opening security screen (not shown) is provided as a login screen to users that are entering their “personal HowZone”. Such an opening security screen, or login screen, includes user identification information (identifier 138 of FIG. 1) and a password which are entered into a web site identification block in the form of text and/or numeric information. For example, an opening security screen to a user's “personal HowZone” comprises a login and password access screen that is presented to the user by way of Applicant's HowZone.com web site as described below in greater detail with reference to FIGS. 5-61. Further details of such access are also described below in greater detail. B. Category Network FIGS. 6A and 6B, assembled according to FIG. 5, together form a diagram of a home page screen display that a client 110 (of FIG. 1) provides to a user immediately following access to the web site of FIG. 1. For the case of individuals who want to search the web site for information, the user merely navigates through the web site using a web site browser. A generic browser overlay 140 is shown in FIG. 6 in which the screen display 142 is presented. With reference to FIGS. 7-19, 21-37, and 40-52, overlay 140 has been omitted in order to simplify the drawings. However, it is understood that overlay 140 will be used to access and present the corresponding screen displays for such figures to a user. A similar overlay 1140 is shown with respect to FIGS. 53-61. The screen display of FIG. 6 is presented to a user following access to Applicant's HowZone.com web site. One technique for accessing the web site comprises entering a Uniform Resource Locator (URL), or address, that defines the route to a file located on the World Wide Web (WWW). As shown in FIG. 6, the URL address http://www.HowZone.com is entered within an address entry field 146 so as to access screen display 142. With respect to navigation within Applicant's web site, HowZone.com, a dynamically generated category network is employed in order to provide relatively easy access to content objects within the web site. A user of Applicant's web site can browse the category network, further described below with reference to FIG. 20, in order to quickly find relevant information in the form of content objects. Various links are provided within the screen displays of Applicant's web site to enable up-tree (toward a point of entry) and down-tree (downward away from a point of entry) navigation within the category network. For example, clicking on a link within the category tree as displayed on screen display 142 results in the display of a content detail page corresponding with such link. The content is then categorized and the presentation order is determined by a relative ranking of the content. In order to organize content, Applicant's web site performs content categorization and ranking. Furthermore, Applicant's web site assigns relative value to the organized content, and further helps users find the organized content, as will be described below in greater detail in the screen displays corresponding with the following figures. Applicant's web site, HowZone.com, provides a descriptive content detail page for each content object. Additionally, users of a content object can rank the content object, with the rankings being aggregated on Applicant's web site where they are periodically generated and displayed. Details of the above-described content object categorization and ranking techniques will be described below in greater detail with reference to FIGS. 8-61. FIG. 6 illustrates a home page screen display which forms a point of entry for a user accessing Applicant's web site by way of an interface at a client. For example, a user accesses web site 128 of client 110 by way of a computer monitor, a keyboard and a mouse (see FIG. 1). Screen display 142 of FIG. 6 includes a URL 144 which is entered by a user desiring to access Applicant's web site which is entered within an address entry field 146 of browser overlay 140. Screen display 142 includes a header 148 which is herein illustrated as a graphical and textual entry, or logo, identifying Applicant's web site as “HowZone.com”. Screen display 142 also includes a “site navigation bar 150” which includes a home page identifier 152. Furthermore, screen display 142 includes a “current category” listing box 154, a “user input” section 156, a “content object links” listing box 158, and an “other embedded” content box 160. As shown in FIG. 6, site navigation bar 150 includes home page identifier 152, which comprises a point of entry for a user entering Applicant's web site, HowZone.com. Such identifier 152 forms a base entry point, or point of entry (POE), for the category tree which is used to hierarchically categorize content objects associated with Applicant's web site. For example, node 1 of FIG. 20 corresponds with the “top” home page identifier 152 of FIG. 6, according to one organization of a category tree. Additionally, site navigation bar 150 includes a “HOME” link 162, a “LOGIN” link 164, a “JOIN” link 166, and an “ABOUT” link 168. As shown in FIG. 6, “HOME” link 162 is disabled because link 162 enables a user to access the screen display of FIG. 6. “LOGIN” link 164 enables a user to navigate to a login screen (not shown) and access their personal HowZone. “JOIN” link 166 enables a user to navigate to a join screen display for enabling a user to obtain their own personal HowZone comprising a personal web page on Applicant's web site and corresponding with FIG. 14. “ABOUT” link 168 enables a user to navigate to a screen display (not shown) that provides information about Applicant's HowZone.com web site to the user. Sub-category listing box 154 includes a plurality of dynamically generated links to sub-categories of the current category. For example, a “business” link 170 enables a user to navigate to a corresponding screen display associated with a node in Applicant's category tree. An associated set of categories, comprising sub-categories of such “business” category, will be displayed within a similar current category listing box. An “other embedded content” box 160 contains embedded content associated with a third-party web site, and containing links which enable a user to access third-party information and/or to conduct purchases. For example, a “buy now” link 178 enables a user to submit a purchase request to a third-party web site in order to buy content such as a featured printer which is displayed within box 160. “User input” section 156 can notify Applicant's web site about information that is not seen on Applicant's web site. For example, “Tell us what you want to learn” link 172 enables a user to inform Applicant's web site about information that they would like to learn. Similarly, “Tell us what you want to share” link 174 enables a user to inform Applicant's web site as to information that they would like to submit to Applicant's web site in order to meet a perceived demand for such information by other users of Applicant's web site. A “content objects link” listing box 158, entitled “My Know-How”, contains an updatable listing of dynamically generated links to content objects that are stored within Applicant's web site, and which correspond with the category presently associated with box 154. For example, a “programming for overachievers” link 176 comprises a link to a content detail page that is accessible by way of a network system that is retrievable over a network-based environment, such as the Internet. Applicant's web site tracks information associated with the content objects that are represented and identified by link 176. For example, a “number of users” field 180 tracks the number of users that have selected the content object represented by link 176. A “current rating” field 182 tracks the average rating that such users have attributed to link 176, after reviewing the content that is associated with link 176. Furthermore, an “access fee” field 184 displays an access fee, or cost, associated with a user retrieving information via link 176. Furthermore, screen display 142 of FIG. 6 includes a footer capable of containing information such as copyright notices for Applicant's web site, as well as a counter 188 that indicates the number of users that have accessed such web site, or a particular screen display associated with such web site. It is envisioned that additional information can be provided within footer 186, such as information that identifies Applicant's web site, wherein such information is easily updatable due to the features of footer 186. FIG. 7 is a diagram of a “business” category screen display that a client provides to a user after clicking on the business sub-category link 170 on the screen display of FIG. 6. More particularly, navigation bar 150 includes a “top” link 190 which allows a user to navigate back to the screen display of FIG. 6, and a “business” present page identifier 192 which corresponds with the “business” category displayed in FIG. 7. As shown in FIG. 7, business present page identifier 192 corresponds with a business category that has a parent of “top” which is located in an up-tree direction from the business category. Current category listing box 154 lists the “departments” or sub-categories that are present in a down-tree direction within the business category. For example, a “technology” sub-category link 194 is provided within current category listing box 154. Furthermore, content objects link listing box 158 contains knowledge and tools associated with the “business” category. For example, content objects link listing box 158 includes a “creating a pdf file from Quark XPress” link 196. A user can navigate to the “technology” sub-category of the “business” category by selecting link 194. Similarly, a user can navigate to a screen display and page which allows a user to gain access to information about how to create a pdf file from Quark XPress by selecting link 196. For purposes of understanding the navigation between screen displays of FIGS. 5-61, it is understood that web site 128 (of FIG. 1) comprises a database-driven web site such that the illustration of fields is understood to include a database behind such fields. Furthermore, a category network is dynamically generated. The category network, described below in greater detail with reference to FIG. 20, uses a building block called a “category” which uses a concept referred to as a “parent”. It is understood that each “category” has a corresponding “parent”. Accordingly, a grandparent, parent, child relationship forms an association which generates a tree structure. It is understood that categories can have multiple parents. However, it is also understood that one or more of the categories may have no parent relationship. As illustrated by the categories and sub-categories provided within navigation bar 150 and listing box 154, each category is displayed to a user by a web browser via Applicant's HowZone.com web site or via a third-party web site. The use of such a third-party web site can potentially have a different visual appearance. Each of such displayed categories has an “up-tree parent” unless the category is point of entry, or home page, identifier 152 (of FIG. 5). Such “up-tree parent” provides a navigable back path, or a hyperlink, that enables a user to navigate all the way up the tree to the point of entry identified by the point of entry, or home page, identifier 152 (of FIG. 5). Additionally, each category has a “down-tree child” which extends as far as the inheritance continues to exist as a navigable path, or hyperlink. Such “down-tree child” is manifest in the form of the sub-categories present within box 154. It is further understood that a selected sub-category, such as “technology” link 194 identified in box 154 will allow a user to navigate to a new screen display which will provide yet further sub-categories to a “technology” category. Additionally, each category has a listing of content objects assigned to the category. It is understood that content objects can be assigned to multiple categories, and that the listing of content objects are assigned to each category as navigable hyperlinks which lead to a page containing information about that content object and providing links to allow the user to join a waitlist, contribute to the content object, or subscribe to the content object. Each category also includes header information. For example, a “HowZone.com header 148” is depicted in FIGS. 6 and 7. Such header information can include one or more of a logo or other graphics, a clickable button, a hyperlink, or other visually perceptible medium. Other information associated with categories includes footer information, such as copyright notices and other information. For example, counter 188 is illustrated in footer 186 of FIG. 6. Finally, each category can have other information such as commercial offerings or sponsorship of third-party links, as will be described below in greater detail with reference to several figures. The use of a footer makes updating of the information relatively easy. A password-protected administrative function is provided in association with the HowZone.com category network. Each category is provided with a unique name, a display name which is not necessarily unique, a parent attribute, a date of creation and date modified fields, one or more display and delete toggles, and include files for use with a page header, a footer, and other embedded information or commerce links. It is understood that all of the “include” files have an optionally selected “subs” inherent function which causes each sub-category beneath this category to inherit and display the same “include” files. Each category is provided with a category identification, or I.D. Additionally, the administrative function includes a display which lists each category, an “add new category” function, and an “edit existing category” function. As discussed above, one characteristic of “categories” present within a category tree is that such “categories” have “include” files. Examples of “include” files are provided by a header, a footer, embedded commerce links or other information. These “include” files have an optionally selected “down-tree inheritance” characteristic which passes on the “include” file. In this case, the inherited “include” file causes all down-tree categories to display the same “include” file. For the case where there is no “include” file assigned to a page or none is inherited from a parent, a default “include” file is caused to be selected and visually displayed. “Include” files can reside on any server that is connected to the World Wide Web (WWW). As a category page is displayed, the “include” files are read and placed into the page. Given the dynamic nature of a category network structure, it is possible for a given department to have multiple parents. In such a case, the inheritance of “include” files is arbitrated by making a specific declaration as to the parent from which an “include” file is inherited. Reference is made to “other information” above. One example of such “other information” is provided by commerce listings such as the content provided within the “other embedded content” box 160 of FIG. 6. The box descriptor “departments” present within listing box 154 describes all the branches extending from a “business category” of the category tree. According to the category tree implemented by Applicant's web site, a user is enabled access at multiple points of entry within the category tree, or network. More particularly, a back path is dynamically generated by forming an ordered list of user selections. This list can be created at any time so as to enable a user to access a point of entry at multiple locations by merely selecting the locations from within the site navigation bar 150 where they are generated and displayed to the user. A user gains access to any particular category page within what the Applicant calls a dynamically generated multiple point of entry category network (DMPCN) by entering a [URL]+[?cid=#], where the “?cid=#” is a category identification. Accordingly, a user can specify any category in this way, and enter the network at that specified point. The point is then referred to as a point of entry (POE). Although the point of entry category may have parent categories, they will not appear to the user entering the category network at this point. Only down-tree children are displayed to a user via the site navigation bar 150 and only once they navigate in a down-tree direction by clicking links in box 154. For example, the point of entry category may not actually be at the top of the network. In the case of the tree shown in FIG. 20, the point of entry may be located at node 2 such that the point of entry is not located at the top of the network, but only down-tree categories appear to a user who uses node 2 as a point of entry. Accordingly, if a user enters the network part way down the tree structure, no upward navigation path is provided to the user, unless a link is explicitly added to the corresponding header file. The provision of a dynamically generated multiple point of entry category network (DMPCN) enables a web site provider to sell sponsors a “private tree”. Sponsors link to the “private tree” by adding to their web site, a hypertext link, button or trigger linking to a HowZone provided URL+[?cid=#] as described above. Such “private trees” can be used to display the sponsors' co-branded commerce by using “include” file. To add further value to the sponsors' web site, no access is provided in an up-tree direction from their private area unless a HowZone.com administrator optionally puts a specific “go-to-top” link in the header of the sponsors' web page. Accordingly, a HowZone.com web site administrator is provided with the ability to sell portions of the overall tree to selected sponsors, and furthermore to implement co-branded commerce. C. Personal Web Page FIG. 8 is a diagram of a “personal HowZone” comprising a private or personal web page for a new user of Applicant's web site, HowZone.com. Users can add relevant information to their personal web page, making selections that are identified from a visually perceptible medium. The screen display of FIG. 8 is absent of any content objects because no content objects have been selected by the new user at this point. A membership login screen (not shown) is provided to a user who wishes to join Applicant's web site in order to obtain a “personal HowZone”, or personal web page. Once registered, the user receives a “personal HowZone” web page, with an associated user identification and a password. Upon receipt of such “personal HowZone” web page, the web page does not initially contain any content objects. A user is then provided with the ability to browse for content objects within Applicant's web site, HowZone.com or within other co-branded HowZones that are accessed via a partner's web site or other distributed information points managed by Applicant's system. Upon finding content objects of interest, the user can add these content objects to their personal web page, or “personal HowZone”. For purposes of this disclosure, it is understood that the term “personal HowZone” comprises a dynamically generated personal web page that is presented and tailored for use specifically by a single, identified user. Upon creation, such web page is empty of any content objects. As shown in FIG. 8, a “personal HowZone”, or personal web page, 198 is shown for “Suzi Henriot”, who is identified within site navigation bar 1150. Navigation bar 1150 includes a user identifier 200, herein identifying “Suzi Henriot”, an “account” link 202, a “contributions” link 204, a “browse” 206, a “my history” link 208, and a “logout” link 210. User identifier 200 enables a user to access their personal account. Link 204 enables a user to make contributions to the HowZone.com web site, as will be described below in greater detail. Link 206 enables a user to browse the HowZone.com web site for content objects which are of potential interest to the user. Link 208 enables a user to review the history of use of content objects they have subscribed to in the past. Link 210 enables a user to logout from their personal web page. A personal content object listing box 212 contains a box descriptor entitled “MY KNOW-HOW”. Within such box 212 are provided specific content objects which have been selected for consumption by the user. However, the screen display of FIG. 8 does not show any content objects since such screen display represents a personal web page for a brand new user. Personal content object listing box 212 also includes an “expires” descriptor 214 and a “ratings” descriptor 216 which identify when access to selected content objects expires, and further identify user-issued ratings for such content objects, which will be described below in greater detail. A bottom portion of listing box 212 includes a “send ratings” button 218 which enables a user to submit and send ratings for content objects that have been added to the user's personal web page and displayed within listing box 212. “Reset” button 220 enables a user to reset “ratings” information that has been entered within “ratings” pull-down menu 236 below “ratings” descriptor 216. FIG. 9 is a diagram of a content detail page which has been selected by a user of the HowZone.com web site corresponding with selecting a link from within content objects link listing box 158 (of FIGS. 6 and 7). By navigating through the dynamic category network of Applicant's web site or other distributed information access point, a user encounters such content objects when browsing through the web site or other distributed information access point, then selects such content objects if they are of interest. The screen display of FIG. 9 comprises a content detail page and includes an “add to your personal HowZone” link 222, which adds the corresponding content object to the user's personal web page 198 (of FIG. 8). More particularly, a corresponding content object entitled “what is a wireless LAN?” will be added to the listing box 212 of FIG. 8 when a user clicks on link 222 of FIG. 9. A content object title 224 is displayed to a user, along with a subscription cost statement 226 and a description 228 of the content object. “Go back” link 227 enables a user to navigate backwards to the screen display of FIG. 8. A “contributor” link 230 opens up a pop-up menu (not shown) that shows a profile of the specific content object contributor. Here, the content object contributor is identified as “John Knapp”. When a user identifies a content object of interest, the user views the content detail page shown by the screen display of FIG. 9. If the user wants to add the content object to their personal HowZone, the user clicks link 222, thereby adding the content object to the user's personal HowZone present within box 212 of FIG. 8. If there is cost associated with adding such content object, the user can pay for the corresponding charge by way of a credit card transaction which is implemented by way of an associated commerce page (not shown) which provides a credit card transaction screen display to be displayed to a user, and from which credit card information can be entered and transmitted therefrom. It is understood that, when a user adds a content object to their personal HowZone, they are actually adding a “link” to that specific content object, wherein the link is actually provided on the user's personal web page, within box 212 of FIG. 8. Such link then enables the user to navigate to the specific content object when viewing their personal HowZone. Once a content object link has been added to a user's personal HowZone, the user can then navigate to such content object by selecting the link from their personal HowZone present within box 212 of FIG. 8. For purposes of this embodiment, link 222 is present in all currently active content objects that are capable of being displayed to a user from Applicant's web site or from a partner's web site. Any user who has an account with Applicant's web site can select content objects by clicking a link on a content detail page and, if required, by paying an access fee. In operation, a selected content object is added to an enrollments database table which maintains a relationship between the specific user and the content objects which have been selected. The enrollments table includes fields for user identification (I.D.), content object identification (I.D.), rating, date record created, date record modified, and date subscription expires. In summary, the following functionality becomes available to a user: browsing content listings, viewing content detail pages, selecting content objects, and paying fees (if required). FIG. 10 is a diagram of the personal web page, corresponding with the personal web page of FIG. 8, but showing the addition of a link to a content object that has been added to the user's personal web page, or personal HowZone. As shown in FIG. 10, a specific content object access link 232 is provided which corresponds with the content object title 224 entitled “what is a wireless LAN?” of FIG. 9. As shown in FIG. 10, box 212 contains link 232 to a specific content object. An expiration date field 234 lists an expiration date of 2000-03-07 beneath the “expires” descriptor 214. A “ratings” pull-down menu 236 is provided beneath the “ratings” descriptor 216, enabling a user to select one of a plurality of ratings that correspond with the content object identified by link 232. A user merely selects button 218 in order to submit, or send, the ratings to Applicant's HowZone.com web site. A user merely selects reset button 220 in order to reset the selected ratings for the content object corresponding with link 232. It is understood that, after selecting a content object by selecting link 222 of FIG. 2, the user can return to his/her personal HowZone in order to access one or more specific content objects by way of link 232 in FIG. 10. After selecting such content object(s) via link 222 of FIG. 9, link 232 appears within the user's “personal HowZone”, or personal web page. In order to create such a dynamically generated personal web page, Applicant's HowZone.com system reads from enrollments tables, and retrieves links to all content objects for that user where the enrollment expiration date is greater than the current date, corresponding with an expiration date provided within date field 234. FIG. 11 is a diagram of a screen display showing one of many alternate methods for displaying content objects associated with Applicant's system. More particularly, “HowZone” content objects are displayed to a user in a small area by way of a hosted, or distributed, HowZone which is located on another web site, such as a third-party web site. These distributed information access points may appear to the user like a banner containing one of a variety of selection methods, a box containing hypertext links or a button, clickable icon or graphic, indicia or link. As shown in FIG. 11, a HowZone.com banner 238 is displayed to a user who is navigating around the World Wide Web (WWW). Upon encountering banner 238, the user can select content objects, and can view the corresponding content detail pages. For example, users will encounter specific HowZone.com banners 238 located on web sites other than HowZone.com's web site. Additionally, users will encounter HowZone.com banners 238 attached or affixed within e-mail. In each case, the user is able to select any content object they desire, and view the corresponding content detail pages. For example, in FIG. 11, banner 238 includes a banner descriptor 244, a scrolling list 242, a “HowZone.com” header 148, a “JOIN” link 246, and a “MyHowZone” link 248. Scrolling list 242 enables a user to scroll through text 250 that corresponds with and describes the content, or content object(s), described by content object link 240 of scrolling list 242. A user who encounters banner 238 merely needs to click on “JOIN” link 246 in order to navigate to a corresponding web page that enables the user to join HowZone.com and to register for their own personal web page. Selection of “MyHowZone” link 248 enables a user who has already registered to access their “personal HowZone”. Selection of link 240 displays a corresponding content detail page which is described below in greater detail with reference to FIG. 12. FIG. 12 is a diagram of a content detail page screen display that a client provides to a user after clicking on the content object link 240 on the screen display of FIG. 11. The corresponding content detail page illustrated in FIG. 12 includes an “add to personal HowZone” link 222. A user can review the content detail page in order to determine whether they want to add a link corresponding with the content object to their “personal HowZone”. If a user decides that they would like to add such link to their personal web site, the user merely clicks link 222. If there is a cost associated with adding such link, the user is then required to complete a credit card transaction by way of a commerce page (not shown) which requests credit card transaction information and authorization from the user. Upon selection of link 222, the link corresponding with the content object is then made available for consumption by the user at the user's personal web page. According to one implementation, the link corresponding to a specific content object is added to the user's personal web page. According to another implementation, an actual content object is added to the user's personal web page. In further implementations, one or more content objects and/or links corresponding with such content objects are added to a user's personal web page in response in selecting link 222. For example, link 222 may add a link and/or a plurality of aggregated content objects to a user's personal web page. Link 222 is present in the content detail pages which correspond to all currently active content objects. A user of Applicant's web site who has an account can select content objects by merely clicking link 222 on the content detail page of FIG. 12 and, if required, by paying an access fee. Selection of the content object is added to an enrollments database table which contains the relationship between a user record within the user database table and the selected content object within the content objects database table. The enrollments table includes fields for user identification, object, identification, rating, date record created, date record modified, and date subscription expires, as was previously described above. Another feature provided by Applicant's system comprises the ability for users to rank content objects in order to help other users select information from Applicant's web site. For example, users can rank content objects that are displayed on Applicant's HowZone.com web site, and other users can review the rankings. Based at least in part on the rankings, those other users can then select information corresponding with the ranked content objects. Individual rankings that are implemented by each user are stored within the enrollments database table. Those rankings are read, and an average ranking is created and stored in a content object database table. This average ranking is read from this database table, and is displayed beside the content object in the content object listing. Furthermore, the average ranking is displayed in the content detail page, and the display order in the content object listing is sorted with the highest ranked content objects being listed first. A content object title 252 is provided, corresponding with the content object associated with link 240 of FIG. 11. FIG. 13 is a diagram of a screen display for a user's personal web page, or “personal HowZone”, that a client provides to a user after clicking on link 222 of FIG. 12. Box 212, shown also in FIGS. 8 and 10, is then updated in response to a user selecting link 222 of FIG. 12, thereby causing the addition of link 196 to a specific content object entitled “creating a pdf file from Quark XPress”. Accordingly, link 196 is added into box 212, along with existing link 232. Accordingly, links 196 and 232 enable a user to access two distinct content objects by way of box 212, and view an expiration date corresponding with each link, as well as to submit a rating for each link via a respective pull-down menu 236. It is further understood that more than one content object can be associated, or integrated, with one link. D. User Ranking of Content Objects As shown in FIG. 14, a user's personal web page, or “personal HowZone”, aggregates content objects that are accessible over a communication medium by a user at an access point. One such access point is provided by the content detail page of FIG. 9, via link 222. Another such access point is provided via banner 238 (of FIG. 11) and by clicking on link 222 (of FIG. 12). The aggregated content objects are selected by a user from one of such access points, wherever such access points reside, and Applicant's web site presents all the content objects to a user in one central location; namely, at the user's personal web page, or “personal HowZone”. After selecting a content object, a user can return to their “personal HowZone” where they can access their content, as shown in FIG. 13. Following selection of the content object, a link corresponding with the content object appears in the user's “personal HowZone”. Alternatively, an actual content object is displayed to a user in their “personal HowZone”, or personal web page. In creating such a dynamically generated personal web page, Applicant's web page and system reads from an enrollments table, and retrieves all content objects from the content object database table for that specific user where the enrollment expiration (or expiry) date is found to be greater than the current date. FIG. 14 is a diagram of a personal web page, or “personal HowZone”, for a user named “John Knapp”. The personal web page contains a listing within box 212, with box 212 having a box descriptor entitled “MY KNOW-HOW”. Box 212 contains a listing of links corresponding with all content objects that the user has selected. Each content object link has a reminder that tells the user when the content object subscription will expire beneath “expires” descriptor 214 in the form of expiration date field 234. Additionally, each content object has an ability to display a rating beneath “ratings” descriptor 216 via “ratings” pull-down menu 236. As shown in FIG. 14, a content object access link 254 is provided to a content object entitled “wireless phone service comparisons”. The content object corresponding with link 254 is set to expire on 2000-05-18, and a user has selected pull-down menu 236, and is about to assign a rating of “5”, wherein ratings are available ranging between 1-10. Following the selection of rating “5”, a user then merely needs to send the rating by selecting button 218. Accordingly, the screen display of FIG. 14 shows a user in the process of using pull-down menu 236 in order to assign a ranking to a specific content object identified by link 254. As shown in FIG. 14, a user has selected pull-down menu 236 via a tactile input device such as a mouse, by clicking on the mouse to open the pull-down menu and then selecting a number ranging between 1-10. A user can repeat such operation for any other content object that is identified by one of the links present within box 212. Accordingly, each content object identified by a link within box 212 and present within a user's personal web page has an associated pull-down menu that is used to rate the corresponding content object(s). On a scale of 1-10, 10 is provided as the highest rating. When a content object is newly added to box 212, displayed as a listing of a new link, the pull-down menu 236 initially appears blank. In order to rate a particular content object, the user manipulates the pull-down menu to select a rating number, then clicks the tactile input device in order to send the selected rating by selecting button 218. According to one implementation, the ability to use pull-down menu 236 and assign a rating to a link corresponding to a new content object is only enabled during the several weeks after a user has subscribed to a specific content object. In effect, the rating that is issued by the user is dynamic, and the user can change the rating at will. FIG. 15 is a diagram showing the personal web page of FIG. 14, but after selecting rating “5” for the content object corresponding with link 254, and after selecting “send ratings” button 218 of FIG. 14. As shown in FIG. 13, a user has sent ratings relating to a link of a content object to Applicant's web site, herein Applicant's HowZone.com system. The screen of FIG. 15 shows one exemplary user's personal web page corresponding with their “personal HowZone”. After clicking button 218 in FIG. 14, the user's content objects listing in the user's personal web page is automatically reordered by Applicant's system, placing highest-ranked links at the top of the individual's personal web page. Such automatic reordering of ranked content object links is one beneficial feature of Applicant's invention. Optionally, actual content objects can be displayed and ranked in a similar manner. It is understood that a user can send content object ratings in the above manner to Applicant's system as often as the user wants to by simply clicking button 218 within box 212 of the user's personal web page. It is also understood that ratings which are sent by a user upon clicking button 218 are stored within an enrollments database table which relates the user to the specific content object. As discussed previously above, such enrollments table includes specific fields, such as a field for a user identification (I.D.), as well as other fields. It is further understood that this aggregated rating which is the average of all ratings issued by all current users of the content object is stored in a content object database table. FIG. 16 is a diagram of a screen display that a client provides to a user corresponding with the screen display of FIG. 7 when navigating Applicant's web page. A content object identified and accessed by link 196 is associated with information that shows the number of users who have accessed the information identified by number of users field 180, the average user rating identified by current rating field 182, and a cost associated with an access fee field 184 which users will pay in order to obtain the information corresponding with link 196. Accordingly, the ratings which are issued by all of the users that have subscribed to a content object are averaged, then displayed in the content object listing via rating field 182. It is important to understand that the content objects are displayed with the most highly rated content objects being listed first. In other words, the content object links are displayed in ranked order. The ratings issued by all users which have subscribed to a content object are added together, and the sum is then divided by the number of users. In other words, the ratings are averaged. The resulting averaged ratings are then stored in a content object database table. The content object listing is a dynamically generated web page which reads and displays information from a database. As this page is being prepared in order to display it to a user, the database is read, and the resulting content objects, along with their ratings, are returned from the database. While the page is being assembled prior to displaying the page to the user, the content objects are sorted into descending order by the average rating. FIG. 17 is a diagram of a screen display that a client provides to a user after the user selects a link corresponding with a content object which shows a content detail page for the corresponding single content object. As is apparent from viewing the screen display of FIG. 17, the same rating is shown in FIG. 17 as was displayed in the category listing of FIG. 16. Accordingly, each content object has a content detail page which also shows the average daily rating. When a user clicks on a content object to view the content detail page, the same rating appears on the content detail page, corresponding with what is shown in FIG. 17. This page is also dynamically generated by a database and it is created in the same way in which information is generated with respect to the screen display of FIG. 16. E. Dynamically Generated Multiple Point-of-Entry Category Network FIG. 18 is a diagram of an add new category screen display that a system administrator for Applicant's web site can access by way of the World Wide Web (WWW). The screen display allows a system administrator to add a new category to a category network within Applicant's web site. It is understood that the page representing the screen display of FIG. 18 is password protected, and only an authorized system administrator can access the corresponding page. Typically, an administrator would be required to enter a name within an internal database name entry box 256 which must be unique. Secondly, the administrator enters a display name within a user readable name entry box 258 which is not necessarily unique. Entry box 256 receives an internal database name comprising an internal name that is used solely within the database, and is viewable only by a system administrator. Entry box 258 receives a user readable name comprising a name which appears in readable form to a user on Applicant's web site. In operation, an administrator then assigns one or more parents to the category “aut.rac”, displayed as “racing”, wherein the assigned parents are displayed within a scrolling list box 260. New category parents are added by selecting one or more category parents, such as “Automobiles” category parent indicator 262, “Sports & Hobbies” category parent indicator 264, and “Competition” category parent indicator 266. Technologies for selecting multiple items within a scrolling list box are presently understood in the art, and entail using a mouse, cursor, and shift or control key to select multiple items. By assigning one or more parents to a category, the administrator determines where in a category network a specific category will appear. A “display this category” section 272 includes a “yes” radio button 268 and a “no” radio button 270, wherein buttons 268 and 270 are alternately selectable by a user in order to determine whether or not a new category will be visibly displayed to users. An administrator can assign “include” files for a header, a footer, and “other” information, such as advertisements, so that a category page will have a desired appearance. Header file section 274 enables the administrator to add a specific header file or cause it to be inherited from a parent by selecting a parent via dynamically generated pop-up menu 286. Similarly, a footer file section 276 enables an administrator to assign “include” files for a footer. Furthermore, “include 1” section 278, “include 2” section 280, and “include 3” section 282 enable the assignment of “include” files for other information, such as advertisements. Each of such sections 274-282 includes an include file entry box 284. A pop-up menu 286 is also provided in order to further define the “include” files and their association. An administrator, perhaps, instead of assigning an include file for a header, a footer, or other information, can use pop-up menus 286 in order to assign a category from which the “include” files will be inherited. Accordingly, they will assume the same appearance. Optionally, an administrator can check a “subs inherit” check box 288 in order to cause other categories, lower on the inheritance tree, to receive the “include” files from this category. As a result, the categories beneath the present one are caused to display the same “include” files, and they will have the same visual appearance to a user. An “add category” button 290 enables addition of the new category to Applicant's tree structure. A “reset” button 292 is provided for resetting information displayed within FIG. 18. A “reload” button 294 is provided in order to reload information presented within the screen display of FIG. 18. A “go back” link 296 enables a user to exit this page without making any changes to, the database or to Applicant's web site. The screen display of FIG. 18, in summary, provides an administrative function and is available to pre-approved staff or administrators of Applicant's web site by way of a password-protected web page (not shown). A category network is made up of individual categories which have an attribute called a parent. For example, a “fax machine” category may have a parent category entitled “office products”, and another parent category entitled “home office”. Such a dynamic parent relationship that allows multiple parents creates a category network. Through a common user interface, categories are given their basic “look and feel” by assigning “include” files to the top portion, or header; the bottom portion, or footer; and various other areas of the page, or “include” files. This hierarchy allows branding to be varied, and further allows a variety of product sales opportunities for companies which wish to partner with Applicant's web site. It is understood that “include” files may be resident on a partner company's web server so that they remain under the partner company's control, and may be modified by the partner company at will. Alternately, they may be uploaded to and stored within Applicant's web site and system or, further alternately, they may be stored on yet another server. In fact, they may be stored on any Internet-connected server capable of storing data and making that data available to the Internet. As shown in FIG. 18, each “include” file section 278, 280 and 282 includes a check box which causes the categories beneath this category, or the ones which have this category as a parent, to use the same “include” files. Accordingly, the categories beneath this category take on the same appearance as the parent category. Such an inheritance allows the category network to have consistent appearance which can be varied on child categories as well. Also adjacent each “include” file section 278, 280 and 282 is a pop-up menu 286 containing a dynamically generated list of all the parent categories. Selection of one of these parent categories causes the category to inherit the appearance imposed by the “include” files on the parent category, or for that matter the parents' parent category. Since a category can have multiple parents, pop-up menu 286 is necessary in order to declare a specific parent from which a specific category should inherit its appearance. As shown in FIG. 18, an “add category” page is shown. Categories can also be edited through the same user interface. This technique allows instant reconfiguration of the category network by adding or changing parents. In operation, category information is stored in a database table, and the parent/child relationships are then stored in a separate database table which is solely employed to store the relationships between categories. If a category has only one parent category, there is only one entry in the relationships database table to identify the sole parent category as a parent to the category in question. If a category has two or more parent categories, there are two or more entries (one for each category-parent relationship) in the relationships database table. FIG. 19 is a diagram of a category network page screen display that a client provides to a user by way of Applicant's web site, and following addition of the category to Applicant's web site using the technique depicted in FIG. 18. The screen display of FIG. 19 is displayed to a user by way of a client such as a computer having a screen display. The screen display of FIG. 19 comprises a web page which represents an “automobiles” category identified by an “automobiles” present page identifier 298. Site navigation bar 150 also includes “top” link 190 which represents a parent category to the “automobiles” category that is identified by the category network page of FIG. 19. Accordingly, FIG. 19 illustrates the “automobiles” category, with current category listing box 154 including a “racing” sub-category link 300, and with content objects link listing box 158 including a textual statement 302 that encourages a user to make a suggestion for desired content objects relating to this topic. Once a category has been added by an administrator, the category immediately appears on each parent category as a selectable hypertext link. For example, the newly added “racing” category appears on the parent “automobiles” category as a sub-category of the “automobiles” category within box 154. A user can navigate to a category page corresponding with the newly added “racing” category merely by clicking on “racing” sub-category link 300. Additionally, a user can trace their previous steps in a backwards direction up the category tree by clicking on link 190, corresponding with the parent category “top”. Such action enables a user to traverse the category network in an “up-tree direction”. Accordingly, it is possible that a new category may not have a content object assigned to it at the time the new category is added. Once content objects have been assigned to the new category, the content objects will appear on the corresponding category page, and the content object can be selected by users for inclusion into their personal web page, or personal HowZone. It is understood that the category network resulting from Applicant's dynamically generated category network is publicly viewable by users and contributors of information. A category is accessed by a user who clicks on the specific category which is displayed within box 154 of a parent category network page. In this manner, a user can navigate from a parent to a child, and thereby traverse the category network in a “down-tree” direction. As shown in FIG. 19, site navigation bar 150 is provided on each page within the category network. Bar 150 provides a historical path that a user has taken in order to navigate to the current category page by displaying a set of navigable links. For example, “top” link 190 is displayed alongside the present category for the category page in FIG. 19. Here, “top” link 190 corresponds with a “TOP” category that is the parent to the “automobiles” category identified by the “automobiles” present page identifier 298. FIG. 20 is an exemplary navigational tree structure realized by Applicant's dynamically generated category network, as implemented using Applicant's system and web site. As shown in FIG. 20, the concept of a dynamic category network is illustrated, wherein individual numbered categories are illustrated as potentially having multiple parents. It is understood that each numbered category corresponds with an actual category, such as the “automobiles” category identified by present page identifier 298 of FIG. 19. For example, category 7 is shown as having parent categories 5 and 6. Because it is possible for a category to have multiple parents, users can take different paths in order to navigate to the same category. For example, a user can enter the category network of FIG. 20 at category 1, and can further navigate to category 7 in one of two possible ways. One way involves navigating successfully through categories 1, 2, 4, and 7. Another way involves navigating successfully through categories 1, 3, 6 and 7. As shown in FIG. 20, a user can also navigate to category 7 by way of categories 5 and 6. It is also possible to enable navigation to category 7 by way of categories 1, 2 or 3, if desirable, by modifying the navigational tree structure. In such a configuration, it would be even easier for a user to navigate to category 7 from various locations within the navigational tree structure, thereby making it easier to navigate through Applicant's web site. The above-described dynamic parent assignment of FIG. 20 imparts a network structure which gives Applicant's web site, HowZone.com, more techniques to present content and to display commerce in front of a user community which is utilizing Applicant's web site and associated functionality. FIG. 21 is a diagram of a “business” category network page screen display that is displayed to a user via a client. More particularly, the screen display of FIG. 21 illustrates the implementation of “include” files which were previously discussed with reference to FIG. 18, as applied to header 148, footer 186, and “other embedded content” depicted in box 160. While navigating the category network of Applicant's web site, users encounter “include” files which impart branding and commerce features to each category page. With reference to header 148, a logo identifying Applicant's web site as “HowZone.com” is illustrated to a user who navigates to the category page of FIG. 21. However, it is understood that any of a number of different textual and/or logo designs could be presented within header 148. For example, a privately branded third-party logo could be illustrated within header 148, along with selected down-tree categories (not shown). It is understood that a privately branded third-party logo comprises a logo that identifies a web page as belonging to a third-party entity, such as some “other” store or Internet site, but which is actually hosted on Applicant's web site under such third-party logo. Footer 186 includes page counter 188. However, it is also understood that footer 186 can include a copyright notice, or any other type of textual and/or graphical information that is easily added/updated within a footer format. Box 160 displays “other” information via a single “include” file which shows a third-party Internet commerce site from which printers can be purchased. For example, the “other” information can include textual and/or graphical information for “ABC Office Products”, a third-party commerce site, including links which enable a user to navigate to the site and purchase identified office products therefrom via box 160. Box 160 includes a commerce content object 304, including one or more links 306. As shown in content object 304, link 306 enables a user to navigate directly to a third-party web site in order to purchase a multiple-function peripheral device having facsimile, printing, copying, scanning, and messaging capabilities. It is understood that one or more of the “include” files can be assigned to the “business” category which is shown in the screen display of FIG. 21. The assignment of such “include” files to a category and corresponding screen display can be carried out by staff of Applicant's web site, or the “include” files can be inherited by sub-categories from a parent, such as from the “top” category parent. For purposes of this disclosure, an “include” file comprises a “snippet” of HTML, which is called by Applicant's web site, HowZone.com, when a page needs to be served to a user who is accessing Applicant's web site. The “snippet” of HTML is then inserted into the rest of the HTML which the user is accessing, thereby making up the category page when the page is requested by a user. Such a modular approach to HTML page assembly is readily understood within the art. However, Applicant has provided the additional feature of “inheritance” of the “include” files which adds a significant benefit over the prior art techniques. Furthermore, Applicant has provided the capability of utilizing multiple parent categories for a single sub-category which further extends the capabilities of Applicant's system over presently understood prior art techniques. FIG. 22 illustrates a screen display showing the “business” category page previously depicted in FIG. 21. However, box 160 displays a different “include” file comprising a commerce content object 1304 that differs from commerce content object 304 (of FIG. 21). As shown in FIG. 22, commerce content object 1304 comprises an advertisement from an office supply store that differs from the office supply store associated with commerce content object 304 (of FIG. 21). Additionally, commerce content object 1304 does not include any links, whereas commerce content object 304 (of FIG. 21) includes links such as link 306 (of FIG. 21) which enables a user to buy an office product from a corresponding office products web site. By changing the “include” file corresponding with commerce content object 1304, the page illustrated by the screen display of FIG. 22 is imparted with a different appearance. Such appearance is changed by an administrator using an administrative function of Applicant's web site whenever it is desirable. An administrator of Applicant's web site can control which “include” files will appear on which category page(s). Furthermore, such administrator can control which “include” files are inherited from specific parent categories, and which “include” files are passed on to child (or sub-) categories. For the case where there are no “include” files specified for a category or inherited from a parent category, a default “include” file is made to appear instead. FIG. 23 illustrates a screen display that depicts a “multiple-point-of-entry” capability that is provided by Applicant's system and web site. As shown by the screen display in FIG. 23, site navigation bar 150 does not include the parent category corresponding with “top” link 190 (of FIG. 22). Instead, only the “business” present page identifier 192, corresponding with the “business” category, is provided on site navigation bar 150. Such an ability to provide “multiple-point-of-entry” capabilities enables Applicant's web site to specially configure a subset of a dynamically generated category tree, wherein the subset supports co-branding in order to present information within one or more distributed access points. According to the screen display of FIG. 23, a co-branded header is depicted as “ABC Office Products”. Such header 1148 differs from header 148 (of FIG. 22) which identifies Applicant's web site as “HowZone.com”. FIG. 23 illustrates the ability to co-brand, or independently label, a subset of Applicant's dynamically generated category tree for selective distribution of information. Independent labelling of selected content is supported by multiple points of entry where each point of entry can appear isolated from other portions of the same dynamically generated category network. In essence, each category within the dynamically generated category network is capable of displaying a unique appearance which is inherited from a parent category up the category tree. Each category includes navigational links and one or more content objects. Each content object is capable of being assigned to multiple categories, and the categories can have multiple parents, as was previously described above. Those categories having multiple parents receive inherited characteristics/features from a specific parent that govern appearance. Each category page within Applicant's category network is accessed with a web browser by entering a Uniform Resource Locator (URL). By appending a category identification (cid), or I.D., a user is enabled entry into the category network at that specific location. More particularly, a ?cid=## is appended to the URL, thereby specifying an entry point. An “up-tree” navigation path is generated as a user traverses a category tree by holding past category identifications (cids) as variables within the current page. The up-tree navigation path is generated using these variables. When entering the category network at a specific point, such as at the “business” category of FIG. 23, the parents of this category are not displayed. As a user proceeds in a “down-tree” direction to categories which are children of the point of entry (POE), the “up-tree” navigation path is displayed to a user within site navigation bar 150. After proceeding along a “down-tree” navigation path, the user can use the displayed “up-tree” navigation links within bar 150 in order to get back to the point of entry, or for that matter any intermediate location identified by a link and displayed within the navigation path. For example, if a user goes to a URL of http://www.HowZone.com, the user will navigate directly to the top of a category tree. If the same user goes to a URL of http://www.HowZone.com?=cid3, that user will be directed to a category I.D. 3, and an “up-tree” path will not be displayed to the user on the screen display. As a user proceeds along a “down-tree” navigation path of a category tree, the “up-tree” navigation path will be displayed to the user. This displayed path gives the user a way to traverse back to any point along the navigation path extending as far back as the original point of entry. For the case where the point of entry is not at the top of the category network, there is no way to navigate to the top of the category tree. Furthermore, the user will not even be made aware that there are any parent categories existing above the topmost category that is provided at the displayed point of entry from which the user first arrived. The user will only be able to traverse the category network in a “down-tree” direction, with the displayed “up-tree” navigation path extending only as far as the original point of entry. Accordingly, this feature gives Applicant's web site the ability to have an infinite number of distinct category trees present within the category network. Furthermore, it enables the category network to support an infinite number of potential customers by enabling co-branding, or independent branding of selected portions of the category tree as identified by the “ABC Office Products” header 1148 of FIG. 23. F. Documentation/Quantification of Demand for Information FIG. 24 illustrates a screen display for an “automobiles” category page including link 172 which is used to collect suggestions from users of Applicant's web site. Link 172 is located on each category page of Applicant's web site. In operation, a user selects, or clicks, link 172 in order to navigate to a user request form which is described below with reference to FIG. 25. Accordingly, link 172 comprises a content object request link that is present on each category page. By selecting link 172, a user navigates to user request form 308 of FIG. 25 where the user can describe and submit their request. Users are then encouraged to disclose to Applicant's web site the specific things that they would like to learn, or in which they show an interest. Accordingly, the process begins when a user clicks link 172, then navigates to form 308 (of FIG. 25) where the user enters information. FIG. 25 illustrates a screen display that presents a request form 308 which enables a user to describe a request regarding information which they would like to learn, and to submit the request. As shown in FIG. 25, a user identification (I.D.) text/data entry field 310 enables a user to enter a user identification. Accordingly, field 310 enables a user to submit their user identification. A suggestion input section 312 includes a plurality of radio buttons which enable a user to identify the type of suggestion being submitted based upon a list of exclusively selectable items that are identified by each radio button 314. A request data entry box 316 is provided into which a user types or imports a description of what the user is requesting. Payment data entry field 318 enables a user to insert a description of what they would be willing to pay for the above-described request, as detailed in box 316. Accordingly, a user can describe what they are interested in. Hence, a user can assign a monetary value to their request. A “submit” button 324 enables a user to submit information which has been added to field 310, section 312, box 316, and field 318. Accordingly, “submit” button 324 enables a user to submit their request to Applicant's web site. A reset button 326 enables a user to reset the information provided within form 308 of FIG. 25. A “go back” link 328 enables a user to return to the screen display of FIG. 24. An “apply for user I.D.” link 320 enables a user to navigate to a screen display where the user can register for and receive a user identification. Typically, the user I.D. comprises a user identification number and/or name. Additionally, a “what are these?” link 322 enables a user to navigate to a screen display (not shown) that explains each of the suggested input sections provided within section 312. As shown in FIG. 25, user request form 308 enables a user to provide information about their specific requests, then submit the information to Applicant's web site, HowZone.com. Accordingly, Applicant's web site is able to document submitted interest in a topic on the part of one or more individuals or users of Applicant's web site. For example, a user can provide a URL which directs staff at Applicant's web site to a specific web page that is related to the user's request, such as by inserting the URL within box 316. Field 318 then enables the user to assign a value, such as a dollar amount, to which the user is willing to pay, which is directly related to the requested information, and which indicates how valuable the provision of the requested information is to that particular user. Applicant's web site then maintains a compilation of user requests within a database. Furthermore, Applicant's web site will notify a user by way of e-mail when the user's requested information becomes available. For example, an information provider may be encouraged to provide such information because of a documented demand which has been accumulated by individuals submitting requests by way of form 308 of FIG. 25, and a user will be notified by e-mail when the information is made available. FIG. 26 illustrates a screen display of an administrative page 330 for Applicant's web site where requests are approved by a system administrator. Administrative page 330 enables a system administrator to review user requests that have been submitted by way of form 308 (of FIG. 25). More particularly, a system administrator accesses a web page corresponding with the screen display of FIG. 26. Such screen display displays a user's request in an editable form 332. The user's request is called up from a database, then loaded into form 332 when the system administrator accesses this editable form 332 of administrative page 330. As shown in FIG. 26, form 332 includes a “contributor” e-mail link 334 which enables navigation back to the user request form 308 of FIG. 25. A contribution-type descriptor 336 is herein identified as a “tutorial”, which corresponds with selected radio button 314 of input section 312 (of FIG. 25). Form 332 also includes a “title” entry box 338, a descriptor entry scrolling list box 340, a “department” pop-up menu 342, a “suggested link” data entry box 344, a “suggested user access fee” data entry box 346, a “suggested user access duration” data entry box 348, a “disposition” section 350 including radio buttons such as “listed” radio button 352, an “edit contribution” button 354, a “reset” button 356, and a “go back” link 358. When an administrator accesses administrative page 330, a user request displays a “disposition” within “disposition” section 350 by selecting the radio button for “conceived”. Such automatic selection of the “conceived” radio button indicates that a suggestion has been “conceived”, or suggested, but the suggestion has not yet been approved by staff or an administrator of Applicant's web site. One feature provided by Applicant's system enables an administrator, upon accessing page 330, to directly contact a user by e-mail in order to discuss the user's request. One such technique would entail providing a link to the contributor's e-mail address directly on one of form 308 and statement 302 of FIGS. 25 and 26, respectively. Optionally, box 344 of FIG. 26 can be configured so as to launch an e-mail program that automatically configures the contributor's e-mail address and prompts the administrator to submit an e-mail to the contributor. An administrator writes a publicly visible title for the user request by inserting a title within title entry box 338. The administrator can then edit the user's description in order to prepare a publicly visible description by editing the text which is provided within descriptor entry scrolling list box 340. The administrator can then assign the user request to a specific category where the request will appear to users of Applicant's web site. Such assignment is carried out by the administrator accessing a list of specific categories which are selected from pop-up menu 342. A system administrator can also add or edit URLs which have been provided by the user, or which the administrator feels is appropriate for the user request. More particularly, a URL is entered and/or revised within “suggested link” data entry box 344. Furthermore, the administrator can add or edit the original dollar value that was assigned by a user by merely editing a “suggested user access fee”, $20.00, that is displayed within access fee data entry box 346, or by entering such a number within box 346. The number entered within box 346 will then become the suggested access fee for a content object that is yet to be created using techniques described further below. By entering a value within “suggested user access duration” data entry box 348, an administrator can assign an access period for the content object which has yet to be created. If an administrator decides to approve a user request, the administrator then sets the “disposition” of the user request within “disposition” section 350 to the “listed” radio button 352, in which case the user request will appear as a content object within the category network of Applicant's web site, HowZone.com. If the administrator decides to reject a user request, the administrator merely needs to set the “disposition” section 350 to the “denied” radio button. For this case, the user request is then discarded. Generally, user requests are stored in the database as a content object. The content object is assigned a status of “conceived”, and it can be edited by staff that maintain Applicant's web site. The user requests do not appear in listings until they have been approved by such staff and/or an approved administrator. Each user request is collected as a free-form description. As part of the approval process, Applicant's web -site staff add a title, and they edit the corresponding description. The staff also assigns the request so that it appears in a particular category, and adds or edits a URL, a suggested access fee and a duration, as discussed above. As a further part of the approval process, such staff attempts to determine the uniqueness and appropriateness of the user request. Such an undertaking by staff may result in reclassification of the request, or in editing of the request, as discussed above in greater detail. Once a user request is approved, the status of the corresponding content object is changed to “listed” within the “disposition” section 350. Content objects that have a “listed” status are then publicly visible, and, at that instant, other users can join a “waitlist” in order to be notified when that content object has been made publicly available for their consumption. As shown in FIG. 26, an administrator selects “edit contribution” button 354 by clicking on the button in order to execute the edits which have been made by the administrator to the user request. FIG. 27 illustrates a screen display showing a newly requested content object that has been approved by an administrator for addition to the category network of Applicant's web site. A pre-existing “racing” link, also shown in FIG. 24, represents a corresponding content object which is accessed by clicking on a “racing” sub-category link 360 within current category listing box 154. A newly requested and approved content object is accessed by way of “Mitsubishi Montero Racing” content object link 362, which is provided to a user within content objects link listing box 158 once the new content object has been approved, and receives a “listed” status. After such receipt, the new content object appears within the category network by adding link 362 within box 158, as well as further displaying associated links indicative of adding the content object within the category tree at various corresponding locations within Applicant's web site. While navigating through Applicant's web site using various links, users can visually identify the names of the corresponding content objects by way of the links, and users can click on such links in order to view information about the requested and approved content objects. As previously discussed with reference to FIG. 26, content objects which have a status of “listed” within “disposition” section 350 (of FIG. 26) are made visible within the category network alongside content objects having a status of “under construction” and “active”. By making “listed” content objects visible alongside “under construction” and “active” content objects, many of content objects are listed within Applicant's web site, and any requested, yet still unavailable, content objects receive significant exposure and viewership which is needed in order to aggregate and/or build consumer demand. It is understood that a user anywhere within Applicant's web site needs to merely click on the associated link, or name, of any content object in order to display an associated content detail page. The action of selecting such an associated link also indicates that a user is interested in such identified content object. FIG. 28 illustrates the screen display for a content detail page for a content object that has not yet been made available to users of Applicant's web site. General information 364 about the content object “Mitsubishi Montero Racing” is displayed to a user. A “join the waitlist” link 366 enables a user to join a waitlist by way of the screen display of FIG. 29. The screen display of FIG. 28 is displayed to a user when the user selects link 362 of FIG. 27. A user can read content object information 364 which pertains to the specific content object. If the user reads the information, then determines that they would like to access this particular content object, the user merely needs to click on link 366 in order to navigate to the screen display of FIG. 29 in order to join a waitlist. Upon joining the waitlist, the user will be notified when the content object will become available for consumption by the user. By reviewing information 364 of FIG. 28, the user becomes aware that the content object that they are interested in receiving does not yet exist in Applicant's web site. Furthermore, the user is given the ability to join a waitlist by way of the screen display of FIG. 29 comprising a list of people who are waiting for this specific content object to be made available to them. By selecting link 366, the user is given the ability to join the waitlist by navigating to the screen display of FIG. 29. Furthermore, the selection of link 366 is a strong indication to the web site host that the user is strongly interested in this particular content object. Such interest can be utilized in efforts to coerce or encourage a content object provider to provide the desired content. Also according to FIG. 28, a “make it happen” link 368 and a “Perhaps You!” link 372 enable a user to become a contributor by navigating to the screen display of FIG. 32. Go back link 370 enables a user to navigate back to the screen display of FIG. 27. FIG. 29 is a diagram of a screen display illustrating a page where a user joins a waitlist. A text entry field 374 is provided to enable a user to enter a user identification. A payment entry field 376 enables a user to enter a payment quantity that they would be willing to pay for receiving the content object that is described in the screen display of FIG. 28. An “apply for user I.D.” link 378 enables a user to submit a request for a user I.D. via a separate screen display (not shown). A waitlist counter statement 380 indicates the number of users currently on the waitlist for this content object. A “submit” button 382 enables a user to submit the information entered within fields 374 and 376 to Applicant's web site, thereby adding them to the waitlist for the content object described in FIG. 28. A “reset” button 384 enables a user to reset the information which has been entered into fields 374 and 376. A “go back” link 386 enables a user to navigate back to the screen display of FIG. 28. After a user selects link 366 of FIG. 28, the user navigates to the screen display of FIG. 29 where they are able to join a waitlist by way of entering information in fields 374 and 376 and by selecting button 382. A user provides their user identification within field 374 and further inputs how much they would be willing to pay to gain access to the content object described in FIG. 28. It is understood that Applicant's web site, HowZone.com, will maintain a waiting list, or waitlist, for content objects that have not yet been made available to users by content providers. Only registered users will be enabled the ability to joint a waitlist. Registered users will be asked to provide their e-mail address, with the e-mail address being stored in a user information database that is accessible by Applicant's web site. The waitlist is then stored in an enrollments database, wherein the enrollments database relates a user with a content object. The user information is stored in a user information database, and the content object is stored in a content object information database. G. Compelling Contribution of Information FIG. 30 is a diagram of a screen display illustrating a content detail page that includes a waitlist. The following group of screen displays disclose the process by which a potential contributor of content objects is approved by authorized staff or an administrator at Applicant's web site. Approved staff at Applicant's web site place a specific content object listing into the category network, or category tree, of Applicant's web site using the administrative page 330 depicted above with reference to FIG. 26. As shown in FIG. 30, a “day trading” content object title 388 is presented to users along with general content object information 1364. The “content object” information 1364 associated with the “day trading” content object of FIG. 30 indicates that “5” users would like this content object, are willing to pay $5.00 for five weeks, and that the “status” indicates that a tutor to provide this content object. Since the “status” indicates that a tutor is needed, the “day trading” content object associated with FIG. 30 has yet to have any content assigned to it. By interacting with the screen display of FIG. 30, users are able to read about the “day trading” content object, then to join a waitlist by way of link 366. A knowledgeable user will see the waitlist, or waiting list, and realize how many people want this specific knowledge indicated by the “day trading” content object and associated description. One technique for encouraging a contributor to meet the aggregated demand that is displayed in FIG. 30 is to have staff of Applicant's web site contact a likely contributor, then make the contributor aware of the waiting list displayed in FIG. 30 which is aggregated via Applicant's “waitlist” feature provided by FIG. 29. Another technique involves contributors navigating through Applicant's web site, then encountering the enumerated number of users who are waiting (by joining the waitlist) to obtain the specific content object. The contributor can also see what these users are willing to pay for the content object. As a result, contributors will be more likely to contribute, and the content library within Applicant's web site will grow relatively quickly as users identify the content objects in which they have an interest, and contributors realize the aggregated demand for the specific content object, as well as the dollar value that individuals are willing to pay to obtain such desired content object. By selecting link 368 or link 372, a potential contributor navigates to the screen display of FIG. 32, where they fill out a form announcing their intent to make a contribution to Applicant's web site. It is understood that Applicant's web site encourages content object contributions from individuals as well as organizations. By displaying the size of the waitlist via user waitlist number display 390 within the screen display of FIG. 30, user demand is plainly made visible to a potential contributor, as well as to other potential users. Furthermore, earning potential is made plainly visible by way of a “suggested access fee” statement 392. Accordingly, a potential contributor merely needs to look at number display 390 and statement 392 in order to realize aggregated user demand, as well as such users' willingness to pay for the content object, thereby showing the size of the waiting list and also showing the earning potential to the potential contributor if they are to contribute the desired content object. According to one business model, Applicant's web site will not always charge an access fee for a user. In such cases, the earning potential for a contributor may actually be zero, and the contributor makes a contribution based solely upon knowledge that the user demand will be met as a result of their contribution being made to Applicant's web site. According to another business model, Applicant's web site will occasionally engage a contributor in a revenue sharing model, wherein advertising revenue and/or access fee revenue is shared with contributors based upon the amount of contribution and/or based upon a defined contractual relationship. FIG. 32 is a diagram of a screen display illustrating a contributor form 394 that an expert uses in order to state their interest in submitting a specific contribution to Applicant's web site. More particularly, FIGS. 32A-32C, assembled according to FIG. 31, form another screen which is accessed by clicking on link 368 or link 372 of FIG. 30. Contributor form 394 includes a description 395 of the terms by which a contributor is encouraged to contribute content, as well as the terms of payment for such contribution. Form 394 also includes a contributor user I.D. field entry box 396. A contributor, in the form of an expert, fills in form 394 by entering their user identification, as well as further information described below. Form 394 also includes a user waitlist number display 390, indicating the number of users currently on the waitlist; an income potential field 400, indicating the immediate income potential pursuant to the terms of the above-described contribution agreement; a suggested content object title entry box 402; a suggested content object description entry box 404; a suggested user access fee entry box 406; a suggested user access duration entry box 408; a contributor qualifications entry box 410; a URL entry box 412; payment method radio buttons 414 and 416; credit card number entry box 418; credit card expiration date entry box 420; credit card user name entry box 422; submit button 424; reset button 426; and “go back” link 428. In an operation, an expert, or contributor, fills in form 394 and, if Applicant's web site charges a fee to host the expert's contribution, the expert provides credit card information by way of selecting one of radio buttons 414 or 416, and filling out boxes 418, 420 and 422. An “I need a user I.D.” link 398, similar to link 378 of FIG. 29, enables a user to navigate to a screen display (not shown) where the user can request and receive a user identification, such as a user identification number. An expert also submits a written summary of their qualifications within box 410. Such written summary aids staff at Applicant's web site in determining the expert's qualifications to contribute content objects to Applicant's web site. An expert can also refer web site staff to a URL by way of box 412 in order to submit content such as submitting an on-line resume for the expert, or to submit sample published content objects in order to discern qualifications of the expert. Experts submit information to Applicant's web site via form 394 which pertains to the expert in order to enable staff at Applicant's web site to make decisions about whether the contributor is truly an expert. Furthermore, staff can determine whether the contributions from this contributor should be added to Applicant's web site. Information collected from form 394 is then stored in a database at Applicant's web site. For the case where Applicant's web site charges an expert a hosting fee in order to keep the expert's content within Applicant's system, the expert's credit card information is obtained from form 394 and the expert is charged a hosting fee, such as a monthly or one-time fee. For the case where an expert's content is based upon “fee-for-access”, Applicant's web site collects fees from users of the expert's content, and where revenue is shared with the contributor (or expert), payments are made to the contributor by issuing a credit against the credit card which is provided within form 394. In this manner, a need to issue checks is eliminated, and a fully automated transaction process is implemented via form 394. From a contributor's standpoint, the contribution of content into Applicant's web site will most likely reduce the credit card balance, in some cases even necessitating the credit card company to disburse money back to the expert who holds the credit card. FIGS. 34A-34B, assembled together according to FIG. 33, comprise a diagram of a screen display showing an approval administrative page 429 where a contributor is approved by an administrator or authorized staff of Applicant's web site. Once a contributor has submitted their information by way of contributor form 394 (of FIG. 32), staff at Applicant's web site are able to use administrative page 429 to review the contributor's qualifications, discuss details with the contributor by way of e-mail, and to decide whether to accept the contributor's contribution by importing it into Applicant's web site where it is made available to users. More particularly, a contributor e-mail link 430 allows an administrative user to send e-mail to the contributor in order to send comments and inquiries to the contributor by way of a separate e-mail client. A particular type of contribution is identified textually within field 432 as a “tutorial”. A title for the contribution is identified by field 434 as “day trading”. A description of the contribution is provided within description field 436 as “something about day trading”. A department is described within a department field 438 shown as a “business” department. A URL field 440 enables the display of an associated URL for an existing document, although none is shown within field 440 of FIG. 34. An anticipated access fee is shown in “access fee” field 442; here the anticipated access fee is $5.00. An anticipated access duration is shown within an “access duration” field 444, here listed as five weeks. A summary of a contributor's qualifications is provided within contributor qualifications field 446. A URL for review by the administrator and/or staff is provided within URL field 448, although none is shown in FIG. 34. A payment method is provided within credit card field 450, with a corresponding credit card number provided within field 452, an expiration date provided within field 454, and a credit card user name provided within field 456. Furthermore, disposition of a contribution is categorized by one of radio buttons 458 and 460. Waiting radio button 458 indicates that the editable contribution is waiting for review by the administrator. Selection of “construction” radio button 460 indicates that the staff has approved the contributor, which changes the status of the content object to “construction”. Once this has occurred, the contributor can make their contribution. Accordingly, Applicant's web site controls the approval process, and only approved contributors can contribute content objects. After the contributor has been approved, a related content object is added to the contributor's list of contributions. This list of contributions is accessed within the contributor's personal web page, or personal HowZone, and the contributor can begin to create, upload, and/or link to the contributor's content. Administrative page 429 also includes an “edit contribution” button 462 which edits the content on the administrative page during the approval process of the contributor. A “reset” button 464 enables the administrator to reset details on the administrative page. A “go back” link 466 enables the administrator to navigate back to exit this function without making changes. H. Distribution of Content Objects to an Audience FIG. 35 is a diagram of a screen display illustrating a “business” category placed within the category network, or category tree, of Applicant's web site. It is understood that Applicant's web site, HowZone.com, does not solely interact with users who access Applicant's web site. Instead, the content on Applicant's web site is delivered to certain users by establishing a visually perceptible presence where the users are connected to a network or users are visiting or shopping. In order to implement this feature, components of Applicant's web site and category tree are broken down into component parts by selecting relevant sub-categories of Applicant's category network, and utilizing a subset of the total number of content objects provided on Applicant's web site. Partner web sites embed the resulting sub-categories, or pages, into the partner web site. Additionally, Applicant's system utilizes specific content objects by putting the content objects into a self-contained HTML content delivery device, or content bomb, that is posted on a third-party web site. Applicant's system also places labeling, or tokens, on products that are located in bricks-and-mortar stores, such as on store shelves, thus making it easy for users to identify relevant content objects of interest in an actual, physical marketplace. Accordingly, several distribution techniques and procedures are provided for placing content objects at visible locations, in front of a relatively large audience of potential consumers. As shown in FIG. 35, users navigate into Applicant's web site, HowZone.com, where they encounter content objects within a category network that are arranged according to a category tree structure, as described above. Typically, a user will start at the top of the category tree; for example, a user might start at “top” link 190, then navigate down to the “business” category identified by “business” present page identifier 192. According to some prior art techniques, web traffic is developed by creating a web site, and traditional advertising and coupon offers are used to drive traffic to the created web site. However, this is a relatively expensive proposition for a company. Applicant's web site, HowZone.com, uses a category system as described above which has a multiple point-of-entry (POE) capability which supports co-branding, and which lets Applicant's web site create partner-specific pages, wherein a partner can embed such pages in their respective web site. FIG. 36 is a diagram of a screen display showing the multiple point-of-entry (POE) capability of Applicant's web site. As shown in the screen display of FIG. 36, the “top” category link of FIG. 35 is not illustrated in FIG. 36. Additionally, the screen display of FIG. 36 illustrates co-branding, wherein header 1148 illustrates the web site as “ABC Office Products”. Accordingly, “ABC Office Products” is a partner that is promoting one or more links to Applicant's web site, wherein the partner can maintain a user's focus on content objects that are relevant to the partner's business and which appear like their own web site. Partners for Applicant's web site then select which categories to list within their portion of the category tree within Applicant's web site. The partners then select which content objects to place within those categories. The partners generate commerce offerings for inclusion on the pages. For example, content box 160 illustrates one such commerce offering. Furthermore, the partners select co-branding page appearance for their portion of the category network present on Applicant's invention. The specifics of such category tree are illustrated within site navigation bar 150, as well as within listing box 154. Applicant's web site furthermore provides a partner with a URL which the partner can use in order to link to a personalized section of the category tree for Applicant's web site. In operation, the partner (here, “ABC Office Products”) drives user traffic to the pages which correspond to their personalized section of Applicant's category network. Users can then add content to their personalized HowZones when viewing the partner web site. Each category page present within the category network of Applicant's invention is accessed by way of a web browser by entering a URL. If a category identification (cid), or I.D., is appended to the URL, then the user will enter the category network at that location. For example, if a user goes to a URL entitled “http://www.HowZone.com”, the user will be at the top of the category tree. If the user goes to a URL of “http://www.HowZone.com?=cid3”, they will be at a category I.D. 3, and no “up-tree” path will appear to the user. It is understood that Applicant's web site will prepare branches of the tree for specific partners, and the partners will be linked to the branches by specifying the appropriate “cid” number. FIG. 37 is a diagram of a screen display showing one alternative method for distributing content to users through one type of distributed information access point. More particularly, a content object distribution mechanism comprising a content object banner 238 is shown embedded within a co-branded web site. Banner 238 is viewed by generic browser overlay 140, and contains a co-branded header 1148, identifying the partner as “ABC Outdoor Equipment”. Banner 238 is displayed alongside ABC web site content 457 displayed on the “ABC Outdoor Equipment” web site. Details of banner 238 were described previously with reference to FIG. 8. According to such description, banner 238 includes a scrolling list 242, a “join” link 246, and a “MyHowZone” link 248. Banner 238 also includes header 148, which indicates the source of banner 238 as identifying Applicant's web site, HowZone.com. The display and distribution of banner 238 by way of third-party web sites provides an interface for users. First, users can read content object descriptions in a pop-up window, then users can click on the “Add to your personal HowZone” link 222 of FIG. 12 in order to add the corresponding content object to their personal web page, or personal HowZone. Secondly, users can join and obtain a free personal web page, or personal HowZone, if they don't already have one. Thirdly, users can access their personal web page, or personal HowZone, by way of link 248. Even furthermore, users can jump to Applicant's web site, HowZone.com, by clicking on header 148, which also serves as a link that enables a user to navigate to the home page of Applicant's web site. As shown in FIG. 37, banner 238 provides an additional distribution method over that previously disclosed with reference to FIG. 36. In operation, partners of Applicant's web site, such as “ABC Outdoor Equipment”, will select individual content objects which they feel will aid the partner in selling more products and/or services to users. Staff at Applicant's web site then put these content objects in a menu selection structure within a “snippet” of HTML. Banner 238 provides one snippet of HTML in which the menu selection structure is found. Accordingly, banner 238 provides a portable piece of HTML which is put onto a web page that is frequented by users who are potentially interested in the selected content objects. Typically, such users will be interested in buying products that are sold by the partner of Applicant's web site, in this case “ABC Outdoor Equipment”. It is further understood that a portable piece of HTML may be distributed using a banner ad, as shown in FIG. 37. However, it is also understood that a “snippet” of HTML can further comprise stand-alone HTML tables of various shapes and sizes and containing similar information and links. It is even further understood that the same information and links can take the form of text containing hypertext links which can be embedded anywhere within any web page. It is understood that the use of banners enables the selling of products. However, banners oftentimes are ignored by users who navigate through a third-party web site. By inserting “snippets” of HTML in the form of “distributed HowZones”, Applicant's web site dispenses know-how, which in turn sells products to users of partner web sites. Accordingly, the enhanced banners 238 distributed by Applicant's web site are generally welcomed by users, and are not ignored. One reason for such banner 238 not being ignored is that traditional functionality is associated with banner 238 because the banner provides the ability to obtain a personal web page on Applicant's web site. Accordingly, content objects can be accumulated and/or aggregated by a user where they can later retrieve such content objects through the collected association of links which have been distributed thereto. For purposes of this disclosure, the enhanced banner 238 is referred to as a “distributed HowZone” which includes self-contained HTML, wherein the self-contained HTML provides a link to one or more servers associated with Applicant's web site. Enhanced banner 238 illustrates one exemplary menu selection structure comprising a scrolling list 242. However, it is understood that the menu selection structure can take any of a number of different forms, including pop-up menus and multiple pop-up menus in which one pop-up menu is embedded in a second pop-up menu, hereinafter referred to as a “pop-up content bomb”. Irrespective of the format of the main selection structure, a user can navigate through a menu selection structure, view content detail pages, and choose content objects. Once a user has selected an element from within enhanced banner 238, a pop-up window provides a description, as in FIG. 12, and a link, such as link 222 of FIG. 12, which the user clicks on in order to add the selected content object to the user's personal web page, or personal HowZone. Accordingly, enhanced banner 238 provides a “distributed HowZone” to users of co-branded web sites, as well as to users of Applicant's web site. Such enhanced banners 238 can also be enabled with a logon function by way of link 248 which enables users to access their personal web page. Furthermore, such enhanced banners 238 can be enabled with a “join” function by way of link 246 which enables a user who does not presently have a personal web page on Applicant's web site to link to Applicant's web site so that they can obtain such a personal web page. It is further understood that content object selections made by a user from any distributed HowZone found on any third-party web site are centrally aggregated into that user's personal HowZone. It is even further understood that the user can access their personal HowZone from within any distributed HowZone on any third-party web site and it will contain all content objects selected by that user from any distributed HowZone or from the HowZone.com web site. The above features are provided by using a content library, as previously disclosed, which contains content object detail pages having a selection link. A user accesses any of these content object detail pages by inputting a URL that is provided in a specified format. One exemplary format is as follows: http://www.HowZone.com/contentdetail.php3?cid=9 The above URL requests a detail page, and provides a content I.D. (cid). The corresponding links on specific items appear in the menu selection structure of enhanced banner 238. When users click an item, the associated content detail page is displayed in response thereto. Accordingly, enhanced banner 238 provides a portable piece of HTML that may be distributed by banner ad distribution companies such as DoubleClick, Inc., which is located at 450 W. 33rd Street, New York, N.Y. 10001. Details of such advertisement distribution over networks is described in U.S. Pat. No. 5,948,061, assigned to DoubleClick, Inc., herein incorporated by reference. FIG. 38 is a simplified schematic diagram showing a point-of-purchase customer, or user, 468 encountering a product package 459 on which a content distribution token 461 is applied. Token 461 includes a web site identifier 463 and indicia 465. Indicia 465 provides a distribution mechanism that is associated with at least one content object. User 468 enters a personal user number and indicia 465 in order to cause distribution of the associated content objects to be distributed to the user's personal web page within Applicant's system. Further details on how the indicia are entered in order to induce the distribution are described below in greater detail with reference to FIG. 39. As shown in FIG. 38, product package 459 contains a label, or token, which is provided in a visibly perceptible location on package 459. Optionally, token 461 can be applied or printed directly onto a product. Even further optionally, token 461 can be provided on a brochure, pamphlet, leaflet, billboard, or other advertising circular, or for that matter, on any visually perceptible medium from which the user can visibly discern indicia 465. Accordingly, such indicia can be submitted to Applicant's web site and server by way of a wireless web appliance 467, as previously described above with reference to FIG. 1. According to one implementation, product package 459 represents a product which is sold by a partner of Applicant's web site at a “bricks-and-mortar” physical store. In addition to having product features printed directly on the product package, token 461 comprises a label that is adhered and/or printed onto the box or package 459. Furthermore, such label is reprinted in product documentation and on the product itself. Accordingly, token 461 enables yet another distribution technique for distributing the location of content objects to users by way of Applicant's system and web site. Partners of Applicant's web site will select individual content objects they think will help them sell the product within product package 459. Staff at Applicant's web site then associate these content objects by way of database records containing links to content on Applicant's web site servers, or located elsewhere. These content objects are associated one to the other, and the staff generate a product-specific identification number that corresponds with an aggregated set of content objects, comprising indicia 465. Such staff maintain the association as long as the partner relationship exists. Accordingly, Applicant's web site provides a web-based user selection facility, wherein the entering of indicia 465 selects the associated content objects, and puts links to the content objects in the user's personal web page. Optionally, the content objects can be directly distributed to the user's personal web page in response to receipt of indicia 465 being delivered from the user via appliance 467 and Applicant's web site. Applicant also provides artwork representing the logo for Applicant's web site, as well as product-specific indicia 465, representing an identification number relating to Applicant's web site and which relates to the product, and which can be placed on the product packaging, on product documentation, directly on the product, or on the partner's web site. Furthermore, the indicia 465 can be placed in advertisements that are distributed by the partners or by other third parties. As shown in FIG. 38, users 468 encounter indicia 465, comprising identification numbers, while they are shopping at a bricks-and-mortar store, or while they are reading a paper or other written material. The user then connects to Applicant's web site, HowZone.com, via wireless web appliance 467. A user selection facility as described above supports web-enabled appliances, such as a web-enabled cell phone, as well as standard web browsers. Depending on the type of user, separate facilities are provided to support access. Also, content objects which are associated with a product-specific indicia 465 may include one or more of the following: user guides for complex products, on-line warranty registration interfaces, service request interfaces, support interfaces, tutorials, tips and tricks, application guides, and maintenance reminders. A web-enabled cell phone facility provides limited access to one specific web site whose only purpose is accepting input from indicia 465 by users, comprising identification numbers. It is understood that users connect to Applicant's web site by way of a web cell phone or a web personal computer. Such users can input their user identification and a product-specific identification number comprising indicia 465. Applicant's web site and system put the content objects associated with the product-specific indicia 465 into the user's personal HowZone. Alternatively, Applicant's web site and system place links to such content objects in the user's personal web page. Accordingly, users consume the content objects, directly or indirectly, and the users are enticed to buy more product which is associated with token 461. FIG. 39 illustrates in greater detail a user interface 470 for wireless web appliance 467. More particularly, user interface 470 includes a screen display 472 comprising a “select token” element 474, a “token indicia” element 476, a “user I.D.” element 478, and a “go” button 480, and a key pad 482. Element 474 indicates to a user that they are to select information off a particular token with indicia 465 (of FIG. 5) being entered within “token indicia” element 476, and a user identification being inserted within “user I.D.” element 478. “Go” button 480 is selected in order to submit the corresponding indicia and user identification to Applicant's web site, wherein the corresponding content objects are loaded into Applicant's personal web page corresponding with the indicia which has been submitted thereby. Key pad 482 enables a user to selectively configure screen display 472 so as to add required information and submit such information therein to Applicant's web site. I. Content Linking, Uploading, and/or Delivery FIG. 40 is a diagram of a screen display illustrating a personal web page, or personal HowZone, 1198 configured for user “John Knapp”. A user identifier 1200 is provided within site navigation bar 1150 entitled “Personalized for John Knapp”. Links 202, 204, 206, 208 and 210 enable navigation through additional web pages of “John Knapp's” personal HowZone. As shown in FIG. 40, “contributions” link 204 is being selected by user “John Knapp” by way of personal web page 1198. Once a user has volunteered to be a contributor to Applicant's web site, and the contribution has been approved by the staff at Applicant's web site, a contributor can access their contributions page by way of their personal web page 1198 via link 204. If a user wants to manage a content contribution, the user accesses their contributions by selecting link 204. Individual content object links such as link 254 are displayed within box 212. Additionally, further details of each content object can be obtained by selecting an associated “more” link 486 that opens a new screen display (not shown) containing more information about the content object. Applicant's web site stores information about content objects, as well as contributors, in databases. All access to these databases is implemented by way of a web browser such as Netscape Navigator or Microsoft Internet Explorer. Applicant's web site makes no distinction between users and contributors, such as between students and teachers, and therefore everyone can be both a student and a teacher. Each user's personal web page, or personal HowZone, holds both content objects that they have selected, as well as content contributions they have made to Applicant's web site. In the latter case, the content contributions are accessed by way of a link which is found within their personal web page, such as by way of content object link 254. The content upload and delivery system of Applicant's web site supports the upload and storage of web content onto servers at Applicant's web site. Furthermore, the content upload and delivery system supports the storage of links to web pages within a database. The management of this content is done by individual users, using their personal web pages. Furthermore, the content is approved by staff at Applicant's web site using the administrative page 585 of FIG. 52. In operation, individual users access content from within their personal web pages, such as from web page 1198 of FIG. 40. FIG. 42 is a diagram of a screen display showing content contributions that a user has made to Applicant's web site. More particularly, FIGS. 40A and 40B, assembled together according to FIG. 41, form another screen which is accessed by selecting link 204 in FIG. 40. Accordingly, a user can visually identify a listing of all content contributions that they have made, as well as statistics associated with each of the listings. More particularly, an exemplary “wireless phone service comparisons” contribution 490 is shown associated with an “edit contributions” link 492 which enables editing of such contribution. Furthermore, contribution 490 is associated with the following information: renewals by way of a renewals field 494, current number of users by way of a current users field 496, total number of users by way of a total users field 498, and ratings by way of an average rating field 500. A user can select a single, specific contribution which they desire to manage by simply clicking on link 492. It is understood that contributions only appear within the listing of FIG. 42 after the contributor has been approved by the staff at Applicant's web site according to the techniques previously described above. The content contributions listing, provided beneath content contributions heading 488, and all related statistics, are stored in a database, and the page which is displayed to a user is dynamically generated, and contains current information. A user selects a content object they wish to manage, then clicks onto the link associated with that content object, such as link 492. It is understood that several different types of content objects are provided within Applicant's web site and system. Several types of links include links to external web pages, links to discussion forums, “tools” like maintenance reminders and on-line warranty registration interfaces, and “tutorials”. By example, a tutorial content object comprises a set of web files, a tutorial specific discussion forum, and student note-taking tools, as well as external web page links. All of the above are stored within Applicant's web site and system. These web files, tools and links are displayed to a user through a content delivery mechanism provided on Applicant's web site, within a standard web browser using JavaScript capabilities. A “go back” link 502 is also provided, enabling a user to navigate back to the screen display of FIG. 40. FIG. 43 is a diagram of a screen display showing a link content builder page 504 provided for a content object type comprising a link. All other content object types, except for tutorial content objects, use a similar content builder page. As shown in the screen display of FIG. 43, link content builder page 504 includes a “date created/modified” field 506, a contributor profile entry box 508, and other information associated with building content, such as a content title field 509, herein described as “How to Clean a Clogged Drain”. Additionally, page 504 includes a URL entry box 510, a “test URL” link 512, an “Exit, Not Done” button 514, and a “go back” link 518. When a contributor wishes to manage a contribution that takes the form of a link, or any other type of content object, save for a tutorial, the user uses a page such as page 504 in FIG. 43. The contributor inputs their personal profile by typing, or entering, the profile in a standard web page text entry field provided within contributor profile entry box 508. The contributor then inputs a full URL which will become the link that a user retrieves in order to follow and access the content object using Applicant's web site. If a contributor is finished with working on a content object at the present time, but the content object is still not ready for a user, the contributor can click “Exit, Not Done” button 514 so they can save their work, leave and come back at a later time in order to finish work on this content object. If a contributor is done with the work on the content object and is ready to submit it for approval, the user can click on “Exit, Done!” button 516. However, it is understood that approval by staff at Applicant's web site may or may not be required, based upon work flow rules that have been established by Applicant's web site. The above-described information is then stored in a database, and the associated page that a user sees is dynamically generated, with the page containing current information. In most cases, a contributor will want a user to know about the contributor. In order to meet this user desire, the contributor will input a profile within contributor profile entry box 508. The contributor wants the users to be able to access content so they also input a URL into box 510. At this stage in the work flow process, a contributor can only modify their profile and the link to the content object. Applicant's web site and staff maintain control over the other elements which are displayed in non-editable form on page 504. The only way to change the other non-editable elements is by using Applicant's web site administrative page which is shown below in greater detail with reference to FIG. 52. FIG. 44 is a diagram of a screen display illustrating another personal web page 198. A content object access link 520 entitled “How to Clear a Clogged Drain” is provided within box 212 and is associated with a “more” link 522. Upon completion and approval of the content object assigned to link 520 by staff at Applicant's web site, the content object appears within the category network of Applicant's web site, and associated web pages. Therefore, a user can select the content object by way of the associated links which are provided embedded within Applicant's web site. This enables the user to add such content object to their personal, or personalized, web page 198, and the URL that is input by the contributor by way of the content builder page in FIG. 43 is assigned to a hypertext link within the user's personal web page. FIG. 45 is a diagram of a screen display showing a content object that a user has accessed from within their personal web page of FIG. 44 which is accessed by selecting content object access link 520 within FIG. 44. In response thereto, the corresponding content object is presented to a user by way of a separate window 530 comprising the screen display of FIG. 45. More particularly, screen display 528 is generated when a user selects link 520 in FIG. 44 from within their personal web page 198. As a result, the content object is loaded into the user's web browser. The page is loaded into a window which is separate from the one containing the user's personal web page. Accordingly, screen display 528 comprises a separate window from the user's personal web page. The content object types are loaded into separate windows so that a user always has access to their personal web page by merely selecting the other window in which the personal web page is displayed. After a user is done reviewing a content object within screen display 528, the user then closes window 530 in which screen display 528 is presented to the user. As shown in FIG. 45, individual content objects are loaded into a standard web browser window 530, and a user is free to manipulate any links that are found within this content object. For the case of discussion forms or other types of content objects that require a user identification, Applicant's web site and system passes a user identification number into the content object by appending the user identification as an argument onto the link. For example, one appended exemplary user identification link comprises “http:URLaddress.com?userid=1”. Accordingly, a user is not forced to use a second login process. Therefore, access to a personal web page requires login by a user so that Applicant's web site and system know and can monitor the identification of a particular user. FIG. 46 is a diagram of a screen display showing a content builder page 1504 for a “tutorial” type of content object similar to the content builder page 504 for the “link” type of content object of FIG. 43. For the “tutorial” type of content object, content builder page 1504 includes a contributor profile and a contributor profile entry box 534 in which a potential contributor can input their profile information. A content type field 536 identifies the content type as a “tutorial”. A content elements box 538 contains contributed content elements by indicating file names or links, when such content elements were added, as well as when such content elements were last modified. As shown in FIG. 46, no content elements are present within box 538 because the screen display of FIG. 46 shows link content builder page 504 at an initial stage where a “tutorial” type of content object is just starting to be built by a contributor. The screen display of FIG. 46 differs from a screen display showing how content is built for content objects other than a tutorial. For example, content builder page 504 of FIG. 43 shows how content is built for a “link” type of content object. In contrast, link content builder page 1504 of FIG. 46 shows how content is built for a “tutorial” content object. When a contributor has been approved for a “tutorial” type of content object, and the contributor is ready to create a tutorial, the contributor uses the content builder of FIG. 46 in order to upload and, later, manage web files for the contributor's tutorial. As shown in box 538, when a potential contributor first begins, the contributor is presented with an empty content elements box 538. An “add page” link 541 enables a user to begin the process of adding a tutorial which will be stored within the Applicant's web site and system. It is understood that contributor profile entry box 534 is essentially the same as contributor profile entry box 508 (of FIG. 43). The information displayed in the screen display of FIG. 46 is stored in a database that is associated with Applicant's web site. A user sees a page that is dynamically generated and which contains current information that is contained within the database. In operation, a contributor adds a profile, then uploads pages to Applicant's web site and system, more particularly onto one or more servers for Applicant's web site. FIG. 47 is a diagram of a screen display in which a local file selection dialog box 537 is shown opened, wherein a user is in the process of selecting a file from the user's hard disk on a client. By selecting one or more files in a box 537, the user can upload information to the content builder on Applicant's web site. The user uploads files, then stores the files on a web server of Applicant's web site. As shown in FIG. 47, file selection dialog box 537 comprises a Macintosh dialog box which is enabled by a Macintosh operating system provided by Apple Computer, of Cupertino, Calif. However, it is understood that the appearance of the dialog box 537 depends on the operating system of the client computer. As shown in FIG. 47, a file selection dialog box 537 is opened by selecting local file selection browse button 562 that is associated with either a page upload entry box 560 or a graphic upload entry box 564. By selecting one of browse buttons 562, file selection dialog box 537 is opened as shown in FIG. 47. A user then selects either a page or a file for graphic upload by selecting the item from within a file selection scrolling list box 550 utilizing a tactile input device such as a mouse. By way of box 537, a user can select page or graphics files located on the user's hard disk drive via file selection scrolling list box 550. Additionally, it is understood that a user can generate such files ahead of time, then upload the files via box 537. An “eject” button 540 is provided within box 537 to eject a removable floppy disk from a client computer to facilitate uploading of a page or file. A “desktop” button 542 enables a user to navigate to the top of a user's file tree. A “cancel” button 544 enables a user to close file selection dialog box 537. An “open” button 546 enables a user to select a chosen file from file selection scrolling list box 550. The selected file is then added to the content builder add tutorial page 548 (of FIG. 48) before being uploaded to Applicant's web site. The information contained within content builder add tutorial page 548 of FIG. 47 is stored in a database, and the page a user sees is dynamically generated and contains current information. As shown in FIGS. 46 and 49, content elements box 538 comprises an add/edit page, with such page supporting the upload of tutorial web pages and web graphics which may appear within the web pages of a specific tutorial. It is understood that tutorials present within Applicant's web site and system are capable of containing any mix of pages which are stored within Applicant's web site, and links to external web pages. Each element present within a tutorial, including stored web pages and external links, has a title which is used by the tutorial navigation system of Applicant's web site as described below. FIG. 48 is a diagram of a screen display including a content builder add tutorial page 548 showing a completed first tutorial content builder page, including graphics which are being uploaded to Applicant's web site, as selected by way of the screen display 548 including box 537 and button 552 of FIG. 47. Upon completion of the first tutorial, a user then uploads the resulting page to Applicant's web site by selecting “upload/reload page” button 552. Button 552 also enables a user to later modify a page, or graphics on the page, by selecting button 552 in order to reload the files. Accordingly, old files present on Applicant's web site and system are replaced by selecting button 552 during such an operation. A “go back” button 554 enables a user to navigate back to page 1504 of FIG. 46. As shown in FIG. 48, a page title entry box 555 enables a user to insert a page title such as “Introduction”. Additionally, as shown in FIG. 48, a tutorial page can alternatively comprise a remote web page by entering a URL within a remote web page URL entry box 556 (of FIG. 48). A “test URL” link 557 enables a user to test a URL that has been entered within a remote web page URL entry box 556 by navigating to the web page corresponding with the URL. As shown in FIG. 48, a user can assign page order by manipulating the “appears” display order pop-up menu 558 in order to select a page order identifier such as “first”, “last”, or “after page number______”. It is understood that such pop-up menu is dynamically generated, and contains a listing of all current pages that are present within the tutorial. Accordingly, a user can select any one of such pages present within the tutorial, and can insert another tutorial page at a preselected location between such pages that are already present. As shown in FIG. 48, a user can prepare tutorial pages one at a time, then upload the prepared pages by way of box 560 and button 552. It is understood that Applicant's web site and system does not include HTML editing tools. Instead, a contributor builds web pages and graphics using other software such as independently or commercially available HTML editing tools, then uploads the prepared web pages and/or graphics by way of the features provided in the screen display of FIG. 48. FIG. 49 is a diagram of a screen display showing a resultant content builder page 1504 after a tutorial page has been uploaded to Applicant's web site in response to selecting button 552 of FIG. 48. As a result, the content is added onto page 1504. The addition of two pieces of content is shown in content elements box 538. As shown in FIG. 49, contributor profile scrolling text entry box 561 contains a contributor profile entitled “I Know Day Trading Really Really Well”. Content elements box 538 illustrates a page that has been added to the link content builder page 504 as identified within file name field 565, “add graphics” link 567, a “date added” field 569, a “date modified” field 571, and a “delete” link 581. Link 581 enables a user of page 504 to delete content that has been added within box 538. Content elements box 538 also illustrates a chart that has been added therein. Additionally, a user is shown in the process of adding another page by selecting “add page” link 541 which navigates the user back to content builder add tutorial page 548 of FIG. 48. Accordingly, a user can continue to add pages to their tutorial using the features of content builder add tutorial page 548 (of FIG. 48). The resulting information is stored within a database. A user sees a dynamically generated page which contains current information. Accordingly, there is no practical limit to the number of pages that may be contained within a tutorial, except for limitations in memory associated with storing such pages. As shown in FIG. 49, a user may delete any page they have added but no longer want by merely selecting “delete” link 581. Furthermore, a user may add graphics to an existing page, or they may edit an existing page, or an existing graphics object by selecting an edit content element link 563. However, it is understood that the editing of an existing page is limited to the following: changing the title of the existing page; changing the order of the existing page within the tutorial; and uploading a revised version of the existing page. Furthermore, it is understood that the editing of an existing graphic is limited to uploading a revised version of the graphic. Furthermore, it is understood that, within Applicant's web site and system, all uploaded elements for a specific tutorial are stored within a single directory present within the web server of Applicant's web site. FIG. 51 is a diagram of a screen display illustrating a completed tutorial showing four pages and a link which have been added and saved into Applicant's web site and system. More particularly, FIGS. 51A and 51B, assembled according to FIG. 50, form another screen that shows a completed tutorial. After a user has completed adding content objects to their tutorial, the user then tells Applicant's web site that they are done by clicking “EXIT, DONE!” button 516. If the user is not done, but the user wishes to save the work that they have done by adding content objects to their tutorial, the user can return later by selecting “EXIT, NOT DONE” button 514, which saves their work at a location where they can later return to the work to continue adding content objects to the tutorial by way of “ADD PAGE” link 541. Furthermore, “GO BACK” link 518 enables a user to navigate backwards to the screen display of FIG. 42. The information contained within page 1504 in FIG. 51 is stored in a database, and the page is dynamically generated when requested by the user and contains information read from the database as the page is generated. It is understood that the content elements displayed within FIG. 51 can include links to external files. The editing of such content elements will be limited to: changing the title of a content element; changing the order of content elements within the tutorial; and changing the URL associated with locating the content element. It is further understood that tutorials within Applicant's web site and system will have tutorial-specific discussion forms, and a student note-taking capability. FIG. 52 is a diagram of a screen display showing an administrative page 585 that enables staff at Applicant's web site to approve a content object that is being contributed by a specific contributor identified by link 430. The type of contribution is identified by field 432. An approval team of staff members at Applicant's web site is provided with the ability to use private administrative pages, such as page 585, to issue approvals when a content object is completed. Such approval team staff members are provided with the ability to edit the name, description, location within the category network, URL, access fee (if any), and access duration (if limited). Such editing is carried out by way of modifying the content presented within title field 1434, description field 1436, department field 1438, existing document URL field 1440, suggested user access fee field 1442, and suggested user access duration field 1444. A “test URL” link 583 enables a user to test view the content provided at the corresponding URL within field 1444. Mutual selection of one of radio buttons 566, 568 or 570 enables an administrative user to selectively configure the disposition of such content object between a status of “under construction”, “ready”, and “open”, respectively. Link 430 provides an e-mail connection with the content provider which enables approval team staff members to discuss the content object by way of e-mail with the associated contributor, using one of a number of e-mail services presently available and understood within the art. Once an approval team staff member at Applicant's web site has determined that the content object is ready to be approved, the staff member then sets the disposition to radio button 568, and clicks “edit contribution” button 1462. “Reset” button 1464 enables such staff member to reset the information provided within page 585. “Go back” link 1466 enables a user to exit the page without making any changes. Information that is input by way of page 585 is stored within a database. The page that a user sees is dynamically generated, and contains current information read from a database as the page is generated. The approval team staff members at Applicant's web site are able to review and approve content objects in order to maintain quality and control of information that is compiled and disseminated by Applicant's web site to users. Additionally, administrative staff members can bypass the approval process if it is determined that such approval process becomes a bottleneck by slowing down distribution of information to users and by disabling such functionality from Applicant's web site. FIG. 53 is a diagram of a screen display showing a content object type of tutorial via a tutorial content object page 572. A tutorial of page 572 contains at least one content object presented within a browser overlay 1140 that identifies Applicant's web site and navigation system. Such browser overlay is illustrated as being provided by a Netscape Navigator Version 4.5. However, it is understood that other types of browsers can also be utilized. As shown in FIG. 53, a pop-up navigation menu 575 enables a user to navigate the content object of page 572 by selecting page titles which bring the user to a specific page of information of the content object. A “close” link 573 enables a user to close the content object of page 572. It is understood that this is one of many potential tutorial navigation and content object presentation methods. Other alternate systems are possible, such as placing navigational links beside or below content or within another browser window. Once a tutorial has been approved and users select the content object so that it is linked and/or added to their personal web page, users can access the tutorial by clicking a link within their personal web page. Such link points to a display in navigation structure provided by browser overlay 1140 and comprising an HTML frame set with a dynamically generated navigation frame presented on top, and with content pages presented below, such as page 572. Accordingly, the individual tutorial pages, such as page 572, linked with, and/or stored within, the web server of Applicant's web site, are loaded into this display structure. A user navigates pages, such as page 572, with the tutorial by using a JavaScript pop-up menu system, such as pop-up navigation menu 575, that is presented within the top frame of browser overlay 1140 within the display and navigation structure. Such information is stored in a database. Accordingly, the tutorial is displayed in a web browser window that is separate from the web browser window containing the user's personal web site. FIG. 54 is a diagram of a screen display showing a dynamically generated pop-up navigation tool/window 574 comprising a window that can be opened by a user within the tutorial delivery system of Applicant's web site. In order to change pages, a user manipulates a tactile input device, such as a mouse, by clicking and dragging across a dynamically generated page list associated with a window of pop-up navigation tool/window 574. When the user releases their mouse, the selected page of the tutorial is presented within the associated bottom frame of page 572. For example, a user is shown releasing their mouse on a selected page 576 entitled “Preflighting Your Publication”. Accordingly, the associated information is retrieved from storage within Applicant's system, and the page is presented to the user. Furthermore, it is understood that pop-up navigation tool/window 574 is formed using standard JavaScript techniques as is known within the art. FIG. 56 is a diagram of a screen display showing another content object page 578 which has just been selected using the pop-up navigation tool/window 574 of FIG. 54. More particularly, FIGS. 56A and 56B, assembled according to FIG. 55, form another screen which shows such page 578 that corresponds with the selected page entitled “Preflighting Your Publication”. FIG. 57 is a diagram of a screen display representing a dedicated discussion forum that each tutorial contains where users can discuss things that they are learning from the tutorial. A user can access the tutorial specific discussion forum by selecting it from navigation pop-up navigation menu 575. A user identity is passed to the forum so that the user does not need to log on to the forum, after previously having logged into Applicant's web site. Accordingly, a second login procedure is eliminated. The information associated with page 582 is stored in a database, and again, the information is dynamically generated and updated as often as every minute. It is understood that the discussion forum functionality provided by such tutorial discussion utilizes a separate application presently available from http://www.araxe.fr/w-agora. Such separate application is integrated within Applicant's web site. FIG. 58 is a diagram of a screen display representing a student notepad page 584 that is provided with each tutorial. More particularly, each tutorial has a dedicated student note-taking function that is enabled by page 584, wherein users can keep their personal notes similar to notes that the user might write within.. the margins of a textbook that they are reading. Such functionality is navigated to by selecting “student notepad” within pop-up navigation menu 575. Accordingly, a user can access the tutorial note-taking tool, which is private and only accessible by such user, by selecting it via pop-up navigation menu 575. The corresponding information is stored within a database, and is updated dynamically as often as every minute. The private note-taking tool functionality utilizes a presently available application, such as that available from http://keilor.cs.umass.edu/diary/index.php3. Such separate application is integrated within Applicant's web site. FIG. 59 is a diagram of a screen display showing the ability for tutorials to contain links to external web pages by selecting a Quark XPress external web page link 586 present within pop-up navigation tool/window 574. Accordingly, a user can access external web pages merely by selecting external web page link 586 via pop-up navigation tool/window 574, using the corresponding pop-up navigation menu 575. Again, the link to the external web page is stored in a database. Furthermore, the tutorial can consist exclusively of external links, wherein a listing of links is merely provided by such tutorial. Such facility, coupled with an access fee in commercial application, enables Applicant's web site the ability to deliver a complete pay-for-use content distribution system and method. FIG. 61 is a diagram of a screen display showing an external web 588 appearing within a tutorial display and navigation system of Applicant's web site. More particularly, FIGS. 61A and 61B, assembled according to FIG. 60, form another screen display showing web page 588 where a user selects an external web page, then loads it within a bottom frame of browser overlay 1140. The user may then manipulate any links that are found within the external web page, such as “support” link 590. The external web pages, present within a tutorial, appear within the same structure as tutorial pages that are stored within a web server of Applicant's web site. In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The storage and retrieval of information has evolved from storing and retrieving information in textbooks and libraries, to storing and retrieving information from online networks such as the Internet. More particularly, the recent adoption and acceptance of online networks such as the Internet has led to a significant increase in the availability of information to the general public. Users frequently access information from the Internet using a personal computer (PC) and a modem. With such a computer, a user can search through the world's best libraries, connect into computer systems located anywhere on the planet, and read online magazines. Furthermore, users can shop for almost anything, located nearly anywhere in the world. However, this greatly expanded capability to retrieve information has led to a syndrome that can best be characterized as “sipping information from a fire hose”. As a result, users become overwhelmed and either fail to find the information they seek or they lose track of the information. As a result of losing track of the information, they cannot find it again at a later point in time. Several techniques have evolved in order to enable a user to collect desirable information from the Internet. However, each of these techniques falls far short of meeting the needs of information providers and information users. More recently, the World Wide Web (WWW) has become the main vehicle for delivering information over the Internet to users. The World Wide Web (WWW) is a network system that enables easy access to distributed documents over the Internet using a client/server architecture. The World Wide Web provides an Internet facility that links documents locally and remotely. A Web document, referred to as a Web page, includes links in a page that let users jump from page to page (hypertext links) whether the pages are stored on the same server or on servers around the world. These Web pages are accessed and read via a Web browser such as Netscape Navigator or Internet Explorer. A user often looks for information on the World Wide Web (WWW) during an online session using a Web search engine, such as AltaVista, Google, or Yahoo! In order to locate items of interest by way of hypertext links, many search engines gather information about content that is available on the Internet using Web crawlers. A Web crawler is a program that gathers information by following hypertext links that have been encountered by the program. The program sends a universal resource locator (URL), as well as document text, back to indexing software on the search engine for each encountered document. The indexing software extracts information from the documents. For example, words, document size and date of creation can be extracted by the indexing software. Such information has been organized into a database, typically based on the frequency of use of individual words present within a document. Accordingly, a keyword search that is implemented by a user with the search engine results in a database being searched, and a search result being generated without actually going directly to the World Wide Web (WWW). The search engine then generates a results page having hypertext links to the Web pages that were located in the database. A user then merely clicks on the link in order to go to the corresponding Web page. However, the World Wide Web (WWW) has merely increased the accessibility of large amounts of information to Internet users. There is a need, therefore, to provide improvements in the way demand for information is identified, content is generated in response to a defined demand, and the way in which users access desired information.
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<SOH> SUMMARY OF THE INVENTION <EOH>A system and method are provided to document and quantify demand for particular information that is a requested by an individual user by sampling a worldwide user community by way of a networked system. Accordingly, user demand is aggregated in order to learn what information is desired by people. The aggregated demand is then used to compel a contributor to contribute information such as content objects. Additionally, information in the form of content objects available on the networked system is enhanced by way of an approval process, by ranking content, and by categorizing content. Furthermore, content is distributed to users in several manners: by way of a primary Web site, and by way of predetermined but dynamic groups of aggregated content objects which are made available via banners and/or tokens. According to one aspect, an apparatus is provided for distributing information over a network-based environment. The apparatus includes a first client, a server, and a second client. The server communicates with the first client via a communication link and includes a database operative to store indicia associated with at least one content object and user identifiers. The second client communicates with the server over a communication link. The second client is remote from the first client and is operative to submit indicia and a user identifier to the server. In response to submission of the indicia and the user identifier, at least one of: (a) a content object, and (b) a link to the content object are received into a personalized access point of the server. The user can access the personalized access point of the server with the first client. According to another aspect, a method is provided for distributing information to users. The method includes: providing a database capable of being associated with content objects that are accessible over a communication medium by a user at a client; associating at least one content object with a distribution mechanism; requesting a desired one of the at least one content object; and receiving the requested content object into a network-based personalized access point. According to yet another aspect, a method is provided for associating content objects with a database wherein the content objects are accessible over a network communication medium by a user. The method includes: receiving a suggestion for a new content object for addition to the database; approving the suggested content object; generating a list of information users desiring the approved content object; compelling an information provider to provide the desired content object based at least in part on demand identified by the generated list; and making the generated content object available to the database. According to even another aspect, a method is provided for distributing information to users. The method includes: providing a database on a server at a first location operative to store indicators that are associated with content objects, wherein the content objects are accessible over a communication link; presenting an indicator at a visually perceptible location to a user; while at a second location, submitting the indicator and a user identifier to the server at the first location; and in response to submitting the indicator and the user identifier, subscribing to one of: (a) a content object associated with the link, and (b) a link to the content object; and receiving one of the content object and the link into a personalized access point; wherein the personalized access point is viewable at a third location provided in communication with the web-based server over a communication link.
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20040628
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20090407
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20050127
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95521.0
| 5
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PARRY, CHRISTOPHER L
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APPARATUS FOR DISTRIBUTING CONTENT OBJECTS TO A PERSONALIZED ACCESS POINT OF A USER OVER A NETWORK-BASED ENVIRONMENT AND METHOD
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
| 2,004
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10,879,671
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ACCEPTED
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Method for manufacturing flash memory device and flash memory device
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The present invention relates to a method for manufacturing a flash memory device and a flash memory device manufactured by the same. In the present invention, an annealing process of a tunnel insulating film is performed at a relatively low temperature to optimize the threshold voltage of a NHVN transistor. Furthermore, in case of portions not compensated through the annealing process of the tunnel insulating film, the quality of the tunnel insulating film is compensated through a subsequent liner oxide film deposition process and a HDP oxide film annealing process. Therefore, the present invention can improve reliability of the tunnel insulating film and thus provide a flash memory device having good properties.
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1. A method for manufacturing a flash memory device, comprising the steps of: forming a tunnel insulating film on a semiconductor substrate; forming a first polysilicon film on the insulating film; forming a pad nitride film on the first polysilicon film; forming a trench by selectively etching the pad nitride film, the first polysilicon film, the tunnel insulating film and the semiconductor substrate; forming a liner oxide film on the inner sidewall of the trench; forming a first oxide film and filling the trench with the first oxide; applying a first annealing process to the first oxide film; removing the pad nitride film; forming a second polysilicon film on the first polysilicon layer exposed by removing the pad nitride film, wherein the first polysilicon film and the second polysilicon film form a floating gate; forming a dielectric film on the entire structure having the second polysilicon layer; forming a control gate on the dielectric film; and forming source/drain regions in the semiconductor substrate exposed between the gates. 2. The method as claimed in claim 1, wherein edges of the second polysilicon layer is overlapped with the first oxide layer. 3. The method as claimed in claim 1, wherein the step of forming the control gate includes: forming a third polysilicon film on the dielectric film; forming a tungsten silicide layer on the third polysilicon film; and patterning the tungsten silicide layer and the third polysilicon film. 4. The method as claimed in claim 1, wherein the first oxide film is formed with high-density plasma (HDP). 5. The method as claimed in claim 1, wherein the step of forming the tunnel insulating film includes the steps of: performing a wet oxidization process for the top of the semiconductor substrate to form a pure oxide; and forming the tunnel insulating film by performing a second annealing process to the pure oxide using a N2 gas. 6. The method as claimed in claim 5, wherein the wet oxidization process is performed under a temperature condition of 750° C. to 850° C. 7. The method as claimed in claim 5, wherein the second annealing process is under a temperature condition of 900° C. to 910° C. 8. The method as claimed in claim 7, wherein the second annealing process is performed for 20 to 30 minutes. 9. The method as claimed in claim 1, wherein the step of forming the tunnel insulating film includes the steps of: performing a wet oxidization process for the top of the semiconductor substrate to form pure oxide; and forming the tunnel insulating film by performing a third annealing process to the pure oxide using a N2O gas. 10. The method as claimed in claim 9, wherein the third annealing process is performed by supplying the N2O gas of 10slm for 10 to 30 minutes. 11. The method as claimed in claim 9, wherein the third annealing process is performed under a temperature condition of 900° C. to 950° C. 12. The method as claimed in claim 9, wherein the step of forming the tunnel insulating film further includes the step of performing a post annealing process using a N2 gas under a temperature condition of 900 to 950° C. for 5 to 30 minutes after the third annealing process. 13. The method as claimed in claim 1, further comprising the steps of performing a dry oxidization process under a temperature condition of 700° C. to 1000° C. to form a wall oxide film before the liner oxide film is formed. 14. The method as claimed in claim 1, wherein the step of forming the liner oxide film is performed under a temperature condition of 800° C. to 850° C. 15. The method as claimed in claim 1, wherein the liner oxide film is formed in thickness of 30 Å to 200 Å. 16. The method as claimed in claim 1, wherein the first annealing process is performed using a N2 gas under a temperature condition of 800 to 950° C. 17. The method as claimed in claim 12, wherein the N2 gas is supplied 5slm to 20slm. 18. The method as claimed in claim 12, wherein the first annealing process is performed for 30 to 120 minutes.
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BACKGROUND 1. Field of the Invention The present invention relates to a method for manufacturing a flash memory device and a flash memory device manufactured by the same, and more specifically, to a method for manufacturing a flash memory device and a flash memory device manufactured by the same, which can improve the quality of a tunnel oxide film. 2. Discussion of Related Art Recently, there is an increasing demand for a flash memory device that can be electrically programmed and erased and has a refresh function of rewriting data in a given period. Research for higher-integration technology of a memory device has been actively made in order to develop a large-capacity memory device capable of storing lots of data therein. In this case, programming refers to an operation of writing data into the memory cell and erasure refers to an operation of erasing data written into the memory cell. For higher-integration of a memory device, an NAND-type flash memory device in which a plurality of memory cells are serially connected (i.e., structure in which a drain or a source among neighboring cells are shard) to form a single string, The NAND-type flash memory device is a memory device from which information is sequentially read unlike a NOR-type flash memory device. The programming and erasure operations of the NAND-type flash memory device are performed by controlling the threshold voltage Vt of the memory cell by injecting or discharging electrons into or from a floating gate through F-N tunneling scheme. In the NAND-type flash memory device, securing reliability of the memory cell is an integral problem. In particular, the data retention properties of the memory cell come to the front as an important problem. As described above, however, in the NAND-type flash memory device, the programming and erasure operations are performed through F-N tunneling scheme. In such repetitive F-N tunneling process, electrons are trapped in the tunnel oxide film of the memory cell, which causes the threshold voltage Vt of the memory cell to shift. Thus, there occurs a case where data originally stored in the memory cell may be erroneously recognized when reading the data. That is, there occurs a problem that reliability of the memory cell is degraded. Shift in the threshold voltage of the memory cell is caused by electrons trapped in the tunnel oxide film by means of repetitive F-N tunneling process due to cycling. In the above, the cycling refers to a process of repeatedly performing the programming operation and the erasure operation. In order to prevent the shift in the threshold voltage of the memory cell, there was proposed a method for reducing an erasure voltage sufficiently below a verify voltage by controlling a bias condition (i.e., bias voltage) upon programming and erasure. In this method, however, the threshold voltage is increased as much as the bias voltage. This still poses a problem that the threshold voltage shifts. As another method for preventing shift in the threshold voltage of the memory cell, there is a method for reducing a thickness of the tunnel oxide film to reduce the amount of electrons trapped at the time of F-N tunneling. This method for reducing the thickness of the tunnel oxide film, however, has a limit due to a fundamental data retention quality problem or a read disturbance problem. SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for manufacturing a flash memory device and a flash memory device manufactured by the same, in which the quality of a tunnel insulating film is improved to minimize a shift in the threshold voltage of a memory cell due to cycling and the data retention quality of the memory cell is thus improved to increase reliability of the memory cell. In order to accomplish the above object, according to a preferred embodiment of the present invention, there is provided a method for manufacturing a flash memory device, comprising the steps of: forming a tunnel insulating film on a semiconductor substrate; forming a first polysilicon film on the insulating film; forming a pad nitride film on the first polysilicon film; forming a trench by selectively etching the pad nitride film, the first polysilicon film, the tunnel insulating film and the semiconductor substrate; forming a liner oxide film on the inner sidewall of the trench; forming a first oxide film and filling the trench with the first oxide; applying a first annealing process to the first oxide film; removing the pad nitride film; forming a second polysilicon film on the first polysilicon layer exposed by removing the pad nitride film, wherein the first polysilicon film and the second polysilicon film form a floating gate; forming a dielectric film on the entire structure having the second polysilicon layer; forming a control gate on the dielectric film; and forming source/drain regions in the semiconductor substrate exposed between the gates. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2, and FIG. 3A to FIG. 3H are cross-sectional view of NAND-type flash memory devices shown to explain a method for manufacturing a flash memory device according to a preferred embodiment of the present invention; FIG. 4 shows CCST (Constant Current Stress Test) quality of a tunnel insulating film fabricated by a manufacture method according to a preferred embodiment of the present invention; FIG. 5 shows CV (Capacitance Voltage) stress quality of a tunnel insulating film fabricated by a manufacture method according to a preferred embodiment of the present invention; FIG. 6 shows bake retention quality of a tunnel insulating film fabricated by a manufacture method according to a preferred embodiment of the present invention; FIG. 7 shows bake retention quality of a tunnel insulating film formed by means of an annealing process using a N2O gas at a temperature of 900° C.; FIG. 8 shows cycling quality depending on a bias of a tunnel insulating film formed by means of an annealing process using a N2O gas at a temperature of 900° C.; and FIG. 9 shows cycling quality depending on a bias of a tunnel insulating film formed by means of an annealing process using a N2O gas at a temperature of 1000° C. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Now the preferred embodiments according to the present invention will be described with reference to the accompanying drawings. FIG. 1 and FIG. 2, and FIG. 3A to FIG. 3H are cross-sectional view of NAND-type flash memory devices shown to explain a method for manufacturing a flash memory device according to a preferred embodiment of the present invention. FIG. 3A to FIG. 3E show portions of a memory cell region CELL in the flash memory device shown in FIG. 1 and FIG. 2. In these drawings, for example a NAND-type flash memory device is shown. Referring to FIG. 1, a P-type semiconductor substrate P-sub 10 is provided. The semiconductor substrate 10 can be divided into a cell region CELL, a low voltage NMOS (LVN) transistor region LVN, a triple LVN (TLVN) transistor region TLVN, a low voltage PMOS (LVP) transistor region LVP, a high voltage NMOS (HVN) transistor region HVN, a native LVN (NLVN) transistor region NLVN, and a native high voltage NMOS (NHVN) transistor region NHVN. A screen oxide film (not shown) is formed on the semiconductor substrate 10. In this case, the screen oxide film is formed in order to prevent the interface of the semiconductor substrate 10 from being damaged due to an ion implantation process performed in a subsequent process. Thereafter, a triple N-well (TN-well) 11 and a P-well 12: are formed within the semiconductor substrate 10. A N-well 13 is then formed in the LVP region LVP. At this time, the TN-well 11 can be formed in a dose of 1.0E13 to 3.0E13 using phosphorus (P) with ion implantation energy of 1.0 MeV to 2.0 MeV. Further, the P-well 12 can be formed through at least three-times ion implantation process. The ion implantation process for forming the P-well 12 is performed in a dose of 1.0E13 to 3.0E13 using boron (B) with ion implantation energy of 500 KeV to 600 KeV and then in a dose of 1.0E13 to 2.0E12 with ion implantation energy of 200 KeV to 300 KeV. Finally, the ion implantation process is performed in a dose of 2.0E12 to 7.0E12 with ion implantation energy of 50 KeV to 200 KeV. At this time, in each step, the tilt is 0° to 45° and the twist is 0° to 270°. At this time, the tilt refers to an implantation angle and the twist refers to an implantation turning angle. Next, in order to form a channel, the LVN transistor region LVN is experienced by a double ion implantation process. The double ion implantation process is performed in a dose of 5.0E111 to 8.0E12 using boron with ion implantation energy of 30 KeV to 70 KeV and then in a dose of 5.0E12 to 8.0E14 with ion implantation energy of 10 KeV to 30 KeV. In each step, the tilt is 0° to 45° and the twist is 0° to 270°. Referring to FIG. 2, a gate oxide film 14 for a high voltage (HV) transistor is thickly formed in the HVN region HVN. In this case, the gate oxide film 14 can be formed by forming a photoresist pattern (not shown) or a pad nitride film (not shown) on the entire structure so that the HVN region HVN is opened, and then performing a wet oxidization process and a annealing process using the photoresist pattern or the pad nitride film as a mask. For example, the gate oxide film 14 can be formed in thickness of 300 Å to 400 Å by performing a wet oxidization process under a temperature range of 750° C. to 800° C. and then performing an annealing process using N2 under a temperature range of 900° C. to 910° C. for 20 to 30 minutes. Next, the gate oxide film 14 of a proper thickness is stripped. At this time, the process of stripping the gate oxide film 14 can be performed in three steps; the first step using buffer oxide etchant (BOE, 300:1), the second step using a H2SO4 solution, and the third step using C-1(NH4OH/H2O2/H2O). Further, it is preferred that in a target at the time of the stripping process, the remaining oxide film remains 15 Å to 45 Å in thickness. Before a tunnel insulating film 15 is formed, the entire structure is experienced by a pre-cleaning process. The pre-cleaning process is performed in order to strip all the oxide films remaining on the entire structure. In this case, the pre-cleaning process can be performed in two steps; the first step using DHF (diluted HF) and the second step using SC-1(NH4OH/H2O2/H2O). Thereafter, the tunnel insulating film 15 is formed on the entire structure. At this time, the tunnel insulating film 15 can be formed in thickness of 60 Å to 90 Å by performing a wet oxidization process under a temperature condition of 750° C. to 850° C. and then performing an annealing process using N2 under a temperature condition of 900° C. to 910° C. for 20 to 30 minutes. Alternately, the tunnel insulating film 15 can be formed in such a way that pure oxide is formed in thickness of 60 Å to 90 Å and an annealing process using N2O gas of 10slm is then performed under a temperature condition of 900° C. to 950° C. for 10 to 30 minutes to form an oxynitride film of 70 Å to 100 Å in thickness. Alternately, the tunnel insulating film 15 can be performed in such a way that pure oxide is formed in thickness of 60 Å to 90 Å, an annealing process using N2O gas of 10slm is performed under a temperature condition of 900° C. to 950° C. for 10 to 30 minutes to form an oxynitride film of 70 Å to 100 Å in thickness, and a post annealing process is then performed using N2 gas at a temperature of 900° C. to 950° C. for 5 to 30 minutes. In the above, the reason why the annealing process is performed under a temperature condition of 900 to 950° C. is that the threshold voltage of the NHVN transistor is lowered if the annealing process is performed at a temperature of over 1000° C. The NHVN transistor is usually used as a transmission transistor in a high voltage pump circuit. This NHVN transistor is not experienced by additional ion implantation process for a high voltage transmission route. Thus, if the annealing process is performed at a temperature of 1000° C. in the process of forming the tunnel insulating film 15, the threshold voltage is too lowered and the circuit thus erroneously operates due to EDR (Electrical Design Rule) spec out. This may cause a serious problem in reliability. For reference, Table 1 below shows the threshold voltage and EDR target of the NHVN transistor depending on a temperature in the annealing process of the tunnel insulating film 15. As shown in Table 1, when the annealing process is performed at a temperature of 1000° C., the low specification of the EDR threshold voltage deviates from −0.27V. TABLE 1 N2O N2O Item EDR Target 900° C. 1000° C. Remark NHVN 1 −0.12 ± 0.15 V −0.186 −0.316 1000° C. (W/L, spec-out 10/3.0 2 25 ± 85 μA/μm 31.572 31.579 3 <10 μA/μm 2.780 3.360 The self-aligned shallow trench isolation (SA-STI) process will be hereinafter described with reference to FIG. 3A to FIG. 3E. For explanation's convenience, explanation on the cell region CELL only will be given. It is determined that other regions except for the cell region CELL can be easily implemented by those skilled in the art through description later. Referring to FIG. 3A, a first polysilicon film 16 is formed on the entire structure. It is preferred that the first polysilicon film 16 is deposited under a temperature condition of 530° C. to 680° C. and at a low pressure of 0.1 torr to 3 torr so that the grain size is minimized to prevent concentration of an electric field. The sing N2O gas of 10slm is then performed under a temperature condition of 900° C. to 950° C. for 10 to 30 minutes to form an oxynitride film of 70 Å to 100 Å in thickness can be deposited in thickness of 200 Å to 800 Å. A pad nitride film 17 is then formed the first polysilicon film 16. The pad nitride film 17 can be deposited by means of a LP-CVD (Low Pressure Chemical Vapor Deposition) method. It is preferred that the pad nitride film 16 is deposited in thickness of 500 Å or more. Reference to FIG. 3B, an ISO (ISOlation) mask 18 is formed on the entire structure. In this case, the ISO mask 18 is formed by covering photoresist on the entire structure and then sequentially performing exposure and development processes using the photomask. Thereafter, the pad nitride film 17, the first polysilicon film 16, the tunnel insulating film 15 and the semiconductor substrate 10 are sequentially etched by means of an etch process using the ISO mask 18, thus forming a trench 19 of a shallow trench isolation (STI) structure. Thereby the semiconductor substrate 10 is defined into a field region and an active region. Then, in order to compensate for the sidewall of the trench 19 that is damaged when the trench 19 is formed, a dry oxidation process is performed. In this case, the dry oxidization process can be performed in a deposition target of 50 Å to 150 Å under a temperature condition of 700° C. to 1000° C. A wall oxide film (not shown) is thereby formed at the sidewall of the trench 19. Furthermore, the oxidization process for forming the wall oxide film can be performed in order to make rounded the top and/or bottom edge portions of the trench 19 and reduce the critical dimension of the active region as well as compensate for etch damage at the sidewall of the trench 19 when the trench 19 is formed. Referring to FIG. 3C, a liner oxide film 20 is formed on the wall oxide film, i.e., on the inner sidewall of the trench 19. In the above, the liner oxide film 20 can be formed by depositing DCS-HTO (Dichlorosilane, SiH2Cl2—High Temperature Oxide) on the inner wall of the trench 19 (actually, on the wall oxide film) in thickness of 30 Å to 200 Å and then performing an annealing process at a temperature of 800° C. to 850° C. The reason why the liner oxide film 20 is deposited on the inner sidewall of the trench 19 is to prevent the tunnel insulating film 15 from being damaged at the edge portion of the active region by plasma in a subsequent process of forming a high-density plasma (HDP) oxide film 21. By reference to FIG. 3D, the HDP oxide film 21 is deposited on the entire structure so that the trench 19 is gap-filled. The HDP oxide film 21 is deposited in thickness of about 4000 Å to 10000 Å. The HDP oxide film 21 is then experienced by an annealing process. At this time, the annealing process can be performed using N2 gas of 5slm to 20slm for 30 to 120 minutes. Alternately, the annealing process can be performed using N2 gas of 5slm to 20slm at a temperature of 800° C. to 950° C. for 30 to 120 miniutes. In this case, the annealing process is a curing process, which is performed in order to improve the properties of the tunnel insulating film 15. Referring to FIG. 3E, the entire structure is experienced by a polishing process. The polishing process can be performed using a chemical mechanical polishing (CMP) process. A uniform EFH (Effective Fox Height) can be obtained on the wafer through the polishing process. Furthermore, the pad nitride film 17 is removed by phosphoric acid (H3PO4). Referring to FIG. 3F, a second polysilicon film 22 is formed on the first polysilicon film 16 exposed by removing the pad nitride film 17. Edges of the second polysilicon film are overlapped with the HDP oxide film 21. The second polysilicon film 22 functions as a floating gate 23 together with the first polysilicon film 16. The second polysilicon film 22 can be formed by depositing a doped polysilicon film under a temperature condition of 400° C. to 600° C. and patterning the doped polysilicon film by means of a lithography process. Referring to FIG. 3G, a dielectric film 27 is formed on the entire structure. At this time, the dielectric film 27 can be formed using oxide/nitride/oxide (ONO). For instance, the oxide film 24 being the bottom layer can be formed in thickness of 40 Å to 60 Å using DCS-HTO under a temperature condition of 800° C. to 850° C. Further, the nitride film 25 being the intermediate layer can be formed in thickness of 40 Å to 80 Å using a nitride film under a temperature condition of 600° C. to 700° C. Lastly, the oxide film 26 being the top layer can be formed in thickness of 40 Å to 60 Å using DCS-HTO under a temperature condition of 800° C. to 850° C. Referring to FIG. 3H, a third polysilicon film 28 is formed on the entire structure. The third polysilicon film 28 functions as a control gate. In this case, the third polysilicon film 28 can be deposited in thickness of 500 Å to 2000 Å using a doped polysilicon film under a temperature condition of 400° C. to 550° C. Also, the doping concentration of the third polysilicon film 28 is 0.5E20/cm2 to 5.0E20/cm2. For explanation's convenience, manufacturing processes hereinafter will be simply described without showing drawings. A tungsten silicide layer Wsix (not shown) and a hard mask layer (not shown) are sequentially formed on the entire structure. An anti-reflective film (not shown) can be also formed on the hard mask layer. The tungsten silicide layer can be deposited in thickness of 500 to 2000 Å under a temperature condition of 400° C. to 500° C. The hard mask layer can be deposited 800 Å to 2000 Å in thickness using PE-TEOS (Plasma Enhanced-Tetra Ethyle Ortho Silicate, Si(OC2H54). The anti-reflective film can be deposited using an oxynitride film in thickness of 300 Å to 1500 Å. Thereafter, an etch process using a lithography process is performed to define gates (including a control gate and a floating gate). Thereby, the tunnel insulating film 15 formed on the semiconductor substrate 10 is exposed between the patterned gates. In this state, a source/drain ion implantation process is performed to form source and drain regions (not shown) within the semiconductor substrate 10 between the gates. In the above, the source/drain ion implantation process can be formed using phosphorus (P) in a dose of 2.0E12 to 8.0E14 with ion implantation energy of 5 KeV to 30 KeV. At this time, the tilt is set to 0° to 45° and the twist is set to 0° to 270°. Through the manufacturing method described above according to a preferred embodiment of the present invention respective transistors including the memory cell are formed. In the above, a few sentences have been described in short for explanation's convenience. However, those skilled in the art will easily implement the flash memory device according to a preferred embodiment of the present invention through the manufacturing method described above. Hereinafter, the quality of the tunnel insulating film manufactured through the manufacturing method according to a preferred embodiment of the present invention will be described. FIG. 4 to FIG. 6 show the quality of the tunnel insulating film fabricated by the method for manufacturing the flash memory device according to a preferred embodiment of the present invention. As described above, FIG. 4 to FIG. 6 show the quality of the tunnel insulating film 15 in case where the tunnel insulating film (15 in FIG. 2) is formed by means of an annealing process using a N2O gas at a temperature of about 900° C., the liner oxide film (20 in FIG. 3C) is deposited in the SA-STI process as the subsequent process, the HDP oxide film (21 in FIG. 3D) is deposited, and the annealing process is then performed. FIG. 4 shows the quality of a constant current stress test (CCST). From FIG. 4, it can be seen that the CCST uniformity of the tunnel insulating film 15 is very good. FIG. 5 shows a capacitance voltage (CV) stress quality of the tunnel insulating film 15. From FIG. 5, it can be seen that the CV threshold voltage is reduced after 1.0 C (−0.01 A/cm2×100 second) stress is applied. Even in the DC stress test, the same result to cycling was obtained. Furthermore, such quality improvements of the tunnel insulating film 15 can be obtained by applying the process of depositing the liner oxide film 20 and the annealing process of the HDP oxide film 21, which are proposed in the manufacturing method according to a preferred embodiment of the present invention. Such quality improvements of the tunnel insulating film 15 can be known through bake. As shown in FIG. 6, if a 512M main chip is baked at a temperature of 250° C. for 48 hours after 10K E/W (Erase/Write) cycling, it can be seen that the programming threshold voltage varies about 0.3V. Moreover, it can be seen that the threshold voltage of the NHVN transistor has almost no change compared to Table 1 and shows a characteristic close to the EDR target, as shown in Table 2. TABLE 2 N2O 900° C. + N2O N2O Liner ox + Item EDR Target 900° C. 1000° C. HDP ANL Remark NHVN 1 −0.12 ± 0.15 V −0.186 −0.316 −0.143 1000° C. spec-out 10/3.0 2 25 ± 85 μA/μm 31.572 31.579 31.579 3 <10 μA/μm 2.780 3.360 3.360 For reference, the main test items for measuring reliability of the memory cell are E/W cycling and bake operation. E/W cycling is a test operation for testing reliability of the memory cell, wherein the programming operation and the erasure operation are repeatedly performed. Usually, the E/W cycling is performed within 10K to 100K considering the lifespan of the memory cell. The bake operation is for testing reliability of the memory cell like the E/W cycling, wherein reliability of the memory cell under the worst condition, in particular a data retention characteristic is tested. The bake operation specified in the data sheet is performed at a temperature of 250° C. for 48 hours. For example, if the programming threshold voltage is changed over 0.5V compared to the initial state after 10K E/W cycling, the program verify threshold voltage condition is 1.0V to 3.0V and a margin for variation in the threshold voltage of a current programmed memory cell (distribution of the threshold voltage in the programmed memory cell is about 1.5V) is thus about 0.5V, so that fail occurs. Distribution of the threshold voltage of the main cell in the test chip is confirmed only for a current program. It is, however, determined that the distribution will be the same even in the erasure. Meanwhile, FIG. 7 to FIG. 9 are views for explaining variation in the quality of the tunnel insulating film. FIG. 7 shows variation in an excessive threshold voltage of a tunnel insulating film due to trapped electrons upon application of 10K cycling after the tunnel insulating film is formed by means of an annealing process using a N2O gas at a temperature of 900° C. As shown in FIG. 7, erasure (−1.5V or less) and programming (1.0 to 3.0V) verify fails occur. The main reason of the data retention quality fail in the bake after the 10K cycling is that as the programming and erasure operations are repeatedly performed formed for F-N tunneling upon 10K E/W cycling, electrons trapped in the tunnel insulating film are re-trapped upon baking performed at a temperature of 250° C., so that the threshold voltage is reduced to about 1.0V. FIG. 8 shows variation in the threshold voltage of a tunnel insulating film when cycling is applied to the tunnel insulating film with varying bias condition after the tunnel insulating film is formed by means of an annealing process using a N2O gas at a temperature of 900° C. In order to prevent fails of programmed and erased cells due to variation in an excessive threshold voltage after 10K cycling, the bias condition is increased and the erasure bias is then set sufficiently lower than the verify bias. However, there is a problem that the threshold voltage is increased as much as the bias is increased. FIG. 9 shows variation in the threshold voltage in the bake after 10K E/W cycling is applied to a tunnel insulating film that is formed by means of an annealing process using a N2O gas at a temperature of 1000° C. It can be seen that the threshold voltage is below 0.2V in case of the tunnel insulating film. As shown in FIG. 7 to FIG. 9, it is most preferred that the annealing process of the tunnel insulating film is performed at a temperature of 1000° C. in view of properties of the tunnel insulating film. As described above, however, there occurs a problem that the threshold voltage of the NHVN transistor is too lowered. If the annealing process of the tunnel insulating film is performed at a temperature of 900° C., however, there is almost no change in the threshold voltage of the NHVN transistor. In the present invention, accordingly, the annealing process of the tunnel insulating film is performed at a temperature of approximately 900° C. to optimize the threshold voltage of the NHVN transistor. Further, portions not compensated through the annealing process of the tunnel insulating film are compensated through a subsequent liner oxide film deposition process and a HDP oxide film annealing process. According to the present invention as described above, an annealing process of a tunnel insulating film is performed at a relatively low temperature to optimize the threshold voltage of a NHVN transistor. Furthermore, in case of portions not compensated through the annealing process of the tunnel insulating film, the quality of the tunnel insulating film is compensated through a subsequent liner oxide film deposition process and a HDP oxide film annealing process, thus improving the quality of the tunnel insulating film. It is thus possible to improve a cell cycling quality and a bake retention quality. Therefore, the present invention has an effect that reliability of the tunnel insulating film is improved to increase the yield. Although the foregoing description has been made with reference to the preferred embodiments, it is to be understood that changes and modifications of the present invention may be made by the ordinary skilled in the art without departing from the spirit and scope of the present invention and appended claims.
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<SOH> BACKGROUND <EOH>1. Field of the Invention The present invention relates to a method for manufacturing a flash memory device and a flash memory device manufactured by the same, and more specifically, to a method for manufacturing a flash memory device and a flash memory device manufactured by the same, which can improve the quality of a tunnel oxide film. 2. Discussion of Related Art Recently, there is an increasing demand for a flash memory device that can be electrically programmed and erased and has a refresh function of rewriting data in a given period. Research for higher-integration technology of a memory device has been actively made in order to develop a large-capacity memory device capable of storing lots of data therein. In this case, programming refers to an operation of writing data into the memory cell and erasure refers to an operation of erasing data written into the memory cell. For higher-integration of a memory device, an NAND-type flash memory device in which a plurality of memory cells are serially connected (i.e., structure in which a drain or a source among neighboring cells are shard) to form a single string, The NAND-type flash memory device is a memory device from which information is sequentially read unlike a NOR-type flash memory device. The programming and erasure operations of the NAND-type flash memory device are performed by controlling the threshold voltage Vt of the memory cell by injecting or discharging electrons into or from a floating gate through F-N tunneling scheme. In the NAND-type flash memory device, securing reliability of the memory cell is an integral problem. In particular, the data retention properties of the memory cell come to the front as an important problem. As described above, however, in the NAND-type flash memory device, the programming and erasure operations are performed through F-N tunneling scheme. In such repetitive F-N tunneling process, electrons are trapped in the tunnel oxide film of the memory cell, which causes the threshold voltage Vt of the memory cell to shift. Thus, there occurs a case where data originally stored in the memory cell may be erroneously recognized when reading the data. That is, there occurs a problem that reliability of the memory cell is degraded. Shift in the threshold voltage of the memory cell is caused by electrons trapped in the tunnel oxide film by means of repetitive F-N tunneling process due to cycling. In the above, the cycling refers to a process of repeatedly performing the programming operation and the erasure operation. In order to prevent the shift in the threshold voltage of the memory cell, there was proposed a method for reducing an erasure voltage sufficiently below a verify voltage by controlling a bias condition (i.e., bias voltage) upon programming and erasure. In this method, however, the threshold voltage is increased as much as the bias voltage. This still poses a problem that the threshold voltage shifts. As another method for preventing shift in the threshold voltage of the memory cell, there is a method for reducing a thickness of the tunnel oxide film to reduce the amount of electrons trapped at the time of F-N tunneling. This method for reducing the thickness of the tunnel oxide film, however, has a limit due to a fundamental data retention quality problem or a read disturbance problem.
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<SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for manufacturing a flash memory device and a flash memory device manufactured by the same, in which the quality of a tunnel insulating film is improved to minimize a shift in the threshold voltage of a memory cell due to cycling and the data retention quality of the memory cell is thus improved to increase reliability of the memory cell. In order to accomplish the above object, according to a preferred embodiment of the present invention, there is provided a method for manufacturing a flash memory device, comprising the steps of: forming a tunnel insulating film on a semiconductor substrate; forming a first polysilicon film on the insulating film; forming a pad nitride film on the first polysilicon film; forming a trench by selectively etching the pad nitride film, the first polysilicon film, the tunnel insulating film and the semiconductor substrate; forming a liner oxide film on the inner sidewall of the trench; forming a first oxide film and filling the trench with the first oxide; applying a first annealing process to the first oxide film; removing the pad nitride film; forming a second polysilicon film on the first polysilicon layer exposed by removing the pad nitride film, wherein the first polysilicon film and the second polysilicon film form a floating gate; forming a dielectric film on the entire structure having the second polysilicon layer; forming a control gate on the dielectric film; and forming source/drain regions in the semiconductor substrate exposed between the gates.
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20041018
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20060801
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20051020
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77616.0
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TSAI, HUI JEY
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METHOD FOR MANUFACTURING FLASH MEMORY DEVICE AND FLASH MEMORY DEVICE
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UNDISCOUNTED
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ACCEPTED
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10,879,703
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ACCEPTED
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Gallium nitride materials and methods associated with the same
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Semiconductor materials including a gallium nitride material region and methods associated with such structures are provided. The semiconductor structures include a strain-absorbing layer formed within the structure. The strain-absorbing layer may be formed between the substrate (e.g., a silicon substrate) and an overlying layer. It may be preferable for the strain-absorbing layer to be very thin, have an amorphous structure and be formed of a silicon nitride-based material. The strain-absorbing layer may reduce the number of misfit dislocations formed in the overlying layer (e.g., a nitride-based material layer) which limits formation of other types of defects in other overlying layers (e.g., gallium nitride material region), amongst other advantages. Thus, the presence of the strain-absorbing layer may improve the quality of the gallium nitride material region which can lead to improved device performance.
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1-32. (canceled) 33. A semiconductor structure comprising: a semiconductor material region; a strain-absorbing layer formed on the semiconductor material region; and a nitride-based material layer formed directly on the strain-absorbing layer, wherein the misfit dislocation density in the nitride-based material layer is less than about 1010 defects/cm2. 34. The structure of claim 33, wherein the semiconductor material region is a substrate. 35. The structure of claim 34, wherein the substrate is substantially planar. 36. The structure of claim 33, wherein the substrate is silicon. 37. The structure of claim 33, wherein the substrate is silicon carbide. 38. The structure of claim 33, wherein the misfit dislocation density is less than about 108 defects/cm2. 39. The structure of claim 33, wherein the misfit dislocation density is less than about 105 defects/cm2. 40. The structure of claim 33, wherein the misfit dislocation density is less than about 102 defects/cm2. 41. The structure of claim 33, wherein the strain-absorbing layer comprises a silicon nitride-based material. 42. The structure of claim 41, wherein the silicon nitride-based material has an amorphous structure. 43. The structure of claim 33, wherein the nitride-based material layer comprises an aluminum nitride-based material. 44. The structure of claim 33, wherein the nitride-based material layer comprises a gallium nitride material. 45. The structure of claim 33, wherein the nitride-based material layer is compositionally-graded. 46. The structure of claim 33, further comprising a gallium nitride material region formed over the nitride-based material layer. 47. The structure of claim 46, further comprising a compositionally-graded transition layer formed between the gallium nitride material region and the nitride-based material layer. 48. The structure of claim 33, wherein the strain-absorbing layer has a thickness of less than 100 Angstroms. 49. The structure of claim 33, wherein the strain-absorbing layer has a thickness of greater than 10 Angstroms. 50. The structure of claim 33, wherein the substrate has a thickness of greater than about 125 micron. 51. The structure of claim 33, wherein the strain-absorbing layer is substantially planar. 52. The structure of claim 33, wherein the semiconductor material region is an underlying layer. 54. The structure of claim 33, wherein the semiconductor material region comprises a gallium nitride material. 55. The structure of claim 33, wherein the semiconductor material region comprises an aluminum nitride-based material. 56. The structure of claim 33, wherein the semiconductor material region comprises a different material than the nitride-based material layer. 57. The structure of claim 33, wherein the semiconductor material region has a different crystal structure than the nitride-based material layer. 58-64. (canceled) 65. A method of forming semiconductor structure comprising: forming a strain-absorbing layer formed on the semiconductor material region; and forming a nitride-based material layer formed directly on the strain-absorbing layer, wherein the misfit dislocation density in the nitride-based material layer is less than about 1010 defects/cm2.
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FIELD OF INVENTION The invention relates generally to gallium nitride materials and, more particularly, to gallium nitride material-based structures including a strain-absorbing layer, as well as methods associated with the same. BACKGROUND OF INVENTION Gallium nitride materials include gallium nitride (GaN) and its alloys such as aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), and aluminum indium gallium nitride (AlInGaN). These materials are semiconductor compounds that have a relatively wide, direct bandgap which permits highly energetic electronic transitions to occur. Such electronic transitions can result in gallium nitride materials having a number of attractive properties including the ability to efficiently emit blue light, the ability to transmit signals at high frequency, and others. Accordingly, gallium nitride materials are being widely investigated in many microelectronic applications such as transistors, field emitters, and optoelectronic devices. In many applications, gallium nitride materials are grown on a substrate. However, differences in the properties between gallium nitride materials and substrates can lead to difficulties in growing layers suitable for many applications. For example, gallium nitride (GaN) has a different thermal expansion coefficient (i.e., thermal expansion rate) and lattice constants than many substrate materials including sapphire, silicon carbide and silicon. This differences in thermal expansion and lattice constants may lead to formation of defects including misfit dislocations. Misfit dislocations may have a number of negative effects including degrading overlying semiconductor material regions when the dislocations propagate to those regions, creation of electronic states within energy bands of those regions that negatively effect device performance, and promoting formation of other types of crystal defects (e.g., point defects, line defects and planar defects). These effects can negatively impact device performance. SUMMARY OF INVENTION The invention provides semiconductor structures including structures that comprise a gallium nitride material region and a strain-absorbing layer, as well as methods associated with the same. In one embodiment, a semiconductor structure is provided. The structure comprises a silicon substrate having a top surface; and, an amorphous silicon nitride-based material layer covering a majority of the top surface of the substrate. A nitride-based material overlying layer is formed on the silicon nitride-based material layer. In another embodiment, a semiconductor structure is provided. The structure comprises a silicon substrate including a top surface; and, a silicon nitride-based material layer having a thickness of less than 100 Angstroms and covering a majority of the top surface of the substrate. A single crystal nitride-based material overlying layer is formed on the silicon nitride-based material layer. In another embodiment, a semiconductor structure is provided. The structure comprises a silicon substrate including a top surface; and, an amorphous silicon nitride-based material layer covering substantially the entire top surface of the silicon substrate and having a thickness of less than 100 Angstroms. A compositionally-graded transition layer is formed on the amorphous silicon nitride-based material layer. A gallium nitride material region is formed on the transition layer. In another embodiment, a semiconductor structure is provided. The structure comprises a semiconductor material region; and, a strain-absorbing layer formed on the semiconductor material region. A nitride-based material layer is formed directly on the strain-absorbing layer, wherein the misfit dislocation density in the nitride-based material layer is less than about 1010 defects/cm2. In another embodiment, a method of forming a semiconductor structure is provided. The method comprises providing a silicon substrate in a reaction chamber; and, introducing a nitrogen source into the reaction chamber to form an amorphous silicon nitride-based material layer. The method further comprises introducing a second source into the reaction chamber to form a nitride-based material overlying layer on the silicon nitride-based material layer. Other aspects, embodiments and features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. The accompanying figures are schematic and are not intended to be drawn to scale. In the figures, each identical, or substantially similar component that is illustrated in various figures is represented by a single numeral or notation. For purposes of clarity, not every component is labeled in every figure. Nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. All patent applications and patents incorporated herein by reference are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 illustrates a gallium nitride material-based semiconductor structure including a strain-absorbing layer according to one embodiment of the present invention. FIG. 2 illustrates a gallium nitride material-based semiconductor structure including a strain-absorbing layer according to another embodiment of the present invention. FIG. 3 illustrates a gallium nitride material-based semiconductor structure including a strain-absorbing layer formed between layers within the structure according to another embodiment of the present invention. FIG. 4 schematically illustrates a FET device including a strain-absorbing layer according to another embodiment of the invention. FIG. 5 is a copy of a STEM (scanning transmission electron microscope) image that illustrates the presence of a silicon nitride strain-absorbing layer between an aluminum nitride layer and a silicon substrate as described in Example 1. FIGS. 6 and 7 are copies of high-resolution TEM images that illustrates the presence of a silicon nitride strain-absorbing layer between an aluminum nitride layer and a silicon substrate as described in Example 1. FIG. 8 is a copy of an image published in R. Liu, et. al., Applied Phys. Lett. 83(5), 860 (2003) that illustrates an aluminum nitride layer and silicon substrate interface without the presence of a silicon nitride strain-absorbing layer as described in the Comparative Example. DETAILED DESCRIPTION The invention provides semiconductor structures including a gallium nitride material region and methods associated with such structures. The semiconductor structures can include a strain-absorbing layer formed within the structure. The strain-absorbing layer may be formed between the substrate (e.g., a silicon substrate) and an overlying layer, or between layers within the structure. As described further below, it may be preferable for the strain-absorbing layer to be very thin, have an amorphous structure and be formed of a silicon nitride-based material. The strain-absorbing layer may reduce the number of misfit dislocations formed in the overlying layer (e.g., a nitride-based material layer) which may limit formation of other types of defects in other overlying layers (e.g., gallium nitride material region), amongst other advantages. Thus, the presence of the strain-absorbing layer may improve the quality of the gallium nitride material region which can lead to improved device performance. FIG. 1 illustrates a semiconductor structure 10 according to one embodiment of the invention. In the illustrative embodiment, the semiconductor structure includes a strain-absorbing layer 12 formed between a substrate 14 and an overlying layer 15. As shown, the structure includes a transition layer 16 formed on the overlying layer and a gallium nitride material region 18 formed on the transition layer. As described further below, the composition, thickness and crystal structure of the strain-absorbing layer may contribute to reducing the number of misfit dislocations in the overlying layer which may decrease defect formation in the gallium nitride material region. This increases the quality of the gallium nitride material region and improves device performance. Semiconductor structures of the invention may form the basis of a number of semiconductor devices including transistors (e.g., FET), Schottky diodes, light emitting diodes and laser diodes, amongst others. When a layer is referred to as being “on” or “over” another layer or substrate, it can be directly on the layer or substrate, or an intervening layer also may be present. A layer that is “directly on” another layer or substrate means that no intervening layer is present. It should also be understood that when a layer is referred to as being “on” or “over” another layer or substrate, it may cover the entire layer or substrate, or a portion of the layer or substrate. The strain-absorbing layer helps absorb strain that arises due to lattice differences between the crystal structure of the substrate and the crystal structure of overlying layer 15 (e.g., when overlying layer 15 is formed of an aluminum nitride-based or gallium nitride material). In the absence of the strain-absorbing layer, this strain is typically accommodated by the generation of misfit dislocations in overlying layer 15 at the interface with the substrate. Thus, by providing an alternative mechanism for accommodating stress, the presence of the strain-absorbing layer may reduce the generation of misfit dislocations. Furthermore, the strain-absorbing layer can help absorb strain that arises due to differences in the thermal expansion rate of the substrate as compared to the thermal expansion rate of the overlying layer and/or the gallium nitride material region. Such differences can lead to formation of misfit dislocations at the overlying layer/substrate interface, or cracking in either the overlying layer and/or gallium nitride material region. As described further below, transition layer 16 also helps absorb this thermally-induced strain. In certain preferred embodiments, strain-absorbing layer 12 is formed of a silicon nitride-based material. Silicon nitride-based materials include any silicon nitride-based compound (e.g., SixNy, such as SiN and Si3N4, SiCN, amongst others) including non-stoichiometric silicon nitride-based compounds. In some embodiments, a SiN strain-absorbing layer may be preferred. Silicon nitride material-based strain-absorbing layers may be particularly preferred when formed directly on a silicon substrate, as described further below. It should also be understood that it is possible for the strain-absorbing layer to be formed of other types of materials according to other embodiments of the invention. Though all of the advantages associated with silicon nitride-based materials may not be achieved in these embodiments. In some embodiments, it is preferable for the strain-absorbing layer to have an amorphous (i.e., non-crystalline) crystal structure. Amorphous strain-absorbing layers are particularly effective in accommodating strain and, thus, reducing the generation of misfit dislocations. However, it should be understood that in certain embodiments of the invention the strain-absorbing layer may have a single crystal or poly-crystalline structure. In these cases, however, all of the advantages associated with the amorphous layer may not be realized. In some embodiments, it is preferred for the strain-absorbing layer to be very thin, particularly when formed of amorphous and/or silicon nitride-based materials. It has been discovered that very thin strain-absorbing layers (e.g., silicon nitride-based strain-absorbing layers) may enable formation of overlying layer(s) having an epitaxial relationship with the substrate, while also being effective in reducing the number of misfit dislocations. In certain cases (e.g., when the strain-absorbing layer is amorphous), it is desirable for the strain-absorbing layer to have a thickness that is large enough to accommodate sufficient strain associated with lattice and thermal expansion differences between the substrate and overlying layer 15 to reduce generation of misfit dislocations. In these cases, it may also be desirable for the strain-absorbing layer to be thin enough so that the overlying layer has an epitaxial relationship with the substrate. This can be advantageous for formation of a high quality, single crystal gallium nitride material region. If the strain-absorbing layer is too thick, then the overlying layer is not formed with epitaxial relationship with the substrate. In some embodiments, the strain-absorbing layer has a thickness of less than about 100 Angstroms which, in these embodiments, can allow the epitaxial relationship between the substrate and the overlying layer. In some embodiments, it may be preferable for the strain-absorbing layer to have a thickness of less than about 50 Angstroms to allow for the epitaxial relationship. The strain-absorbing layer may have a thickness of greater than about 10 Angstroms which, in these embodiments, is sufficient to accommodate strain (e.g., resulting from lattice and thermal expansion differences) and can facilitate forming a strain-absorbing layer that covers the entire substrate, as described further below. In other embodiments, the strain-absorbing layer may have a thickness of greater than about 20 Angstroms to sufficiently accommodate strain. Suitable thickness ranges for the strain-absorbing layer include all of those defined by the ranges described above (e.g., greater than about 10 Angstroms and less than about 100 Angstroms, greater than about 10 Angstroms and less than about 50 Angstroms, and the like). Also, the strain-absorbing layer thickness may be between about 20 Angstroms and about 70 Angstroms. It should be understood that suitable thicknesses of the strain-absorbing layer may depend on a number of factors including the composition and crystal structure of the strain-absorbing layer; the composition, thickness and crystal structure of the overlying layer; as well as the composition, thickness, and crystal structure of the substrate, amongst other factors. Suitable thicknesses may be determined by measuring the effect of thickness on misfit dislocation density and other factors (e.g., the ability to deposit an overlying layer having an epitaxial relationship with the substrate, etc.). It is also possible for the strain-absorbing layer to have a thickness outside the above ranges. In some cases, the thickness of the strain-absorbing layer is relatively uniform across the entire layer. For example, in these cases, the strain-absorbing layer may have a thickness uniformity variation of less than 25 percent, or less than 10 percent, across the entire strain-absorbing layer. As described further below, in some embodiments, the strain-absorbing layer may be formed by nitridating a top surface region of a silicon substrate. That is, the surface region of the substrate may be converted from silicon to a silicon nitride-based material to form the strain-absorbing layer. It should be understood that, as used herein, such strain-absorbing layers may be referred to as being “formed on the substrate”, “formed over the substrate”, “formed directly on the substrate” and as “covering the substrate”. Such phrases also refer to strain-absorbing layers that are formed by depositing a separate layer (e.g., using a separate nitrogen source and silicon source) on the top surface of the substrate and are not formed by converting a surface region of the substrate. In the illustrative embodiment, the strain-absorbing layer covers substantially the entire top surface of the substrate. This arrangement may be preferable to minimize the number of misfit dislocations in the overlying layer. In other embodiments, the strain-absorbing layer may cover a majority of the top surface of the substrate (e.g., greater than 50 percent or greater than 75 percent of the top surface area). Also, in the illustrative embodiment, strain-absorbing layer 12 is formed across the entire area between the substrate and the overlying layer. That is, the strain-absorbing layer separates the substrate and the overlying layer at all points with the strain-absorbing layer being directly on the substrate and the overlying layer being directly on the strain-absorbing layer. This arrangement may be preferable to minimize the number of misfit dislocations in the overlying layer. In other embodiments, the strain-absorbing layer may be formed across a majority of the area (e.g., greater than 50 percent, or greater than 75 percent) between the substrate and the overlying layer. If the strain-absorbing layer is not present across the entire (or, at least, the majority of the) area between the substrate and the overlying layer, the above-noted advantages associated with the strain-absorbing layer may not be realized. The extent that the strain-absorbing layer covers the substrate (and the area between the overlying layer and the substrate) in the present invention may be distinguished from certain prior art techniques in which a discontinuous silicon nitride layer is formed (in some cases, inadvertently) between a silicon substrate and an overlying layer. It should be understood that, in other embodiments, the strain-absorbing layer may be positioned in other locations such as between two different layers (e.g., the embodiment of FIG. 3). In these embodiments, the strain-absorbing layer may reduce the formation of misfit dislocations in the layer that overlies the strain-absorbing layer. As noted above, the presence of the strain-absorbing layer advantageously results in very low misfit dislocation densities within the overlying layer (e.g., at, or very near, an interface between the strain-absorbing layer and the overlying layer). Misfit dislocations typically are formed at (or, very near) the interface between two materials as a result of incoherency due to differences in atomic structures of the materials. In some embodiments of the invention, the misfit dislocation density in the overlying layer is less than about 1010 defects/cm2; and, in other embodiments, less than about 108 defects/cm2. Even lower misfit dislocation densities in the overlying layer may be achieved, for example, less than about 105 defects/cm2. In some cases, the presence of misfit dislocations may not be readily detectable which generally means that the misfit dislocation density is less than about 102 defects/cm2. The specific misfit dislocation density depends, in part, on the particular structure including factors such as the thickness, composition and crystal structure of the strain-absorbing layer; the composition, thickness and crystal structure of the overlying layer; as well as the composition, thickness, and crystal structure of the substrate, amongst other factors. It should be understood that the above-described misfit dislocation density ranges may be found in the overlying layer at, or very near (e.g., 20 nm), the interface with the strain-absorbing layer; and, also may be found at other regions within the overlying layer. Misfit dislocation density may be measured using known techniques. The techniques generally involve inspection of the atomic structure of a sample (e.g., an interface) using high magnification to determine the presence of misfit dislocations over a representative area. For example, high resolution transmission electron microscopy (TEM) may be used. One suitable technique involves counting the number of dislocations over a representative area using high resolution-TEM images. The misfit dislocation density is calculated by dividing the number of dislocations by the area. Typically, the misfit dislocation density is expressed in units of defects/cm2. It should be understood that, in certain embodiments of the invention, the overlying layer may have misfit dislocation densities greater than the above-noted ranges. The very low misfit dislocation densities achievable in the overlying layer in structures of the present invention may lead to a number of advantages including reducing defects in the gallium nitride material region, as described further below. It may be preferred for structure 10 to include an overlying layer 15 formed of a nitride-based material. Suitable nitride-based materials include, but are not limited to, aluminum nitride-based materials (e.g., aluminum nitride, aluminum nitride alloys) and gallium nitride based-materials (e.g., gallium nitride, gallium nitride alloys). In some cases, the overlying layer has a constant composition. In other cases, as described further below, the overlying layer may be compositionally-graded. Suitable compositionally-graded layers are described further below and have been described in commonly-owned U.S. Pat. No. 6,649,287, entitled “Gallium Nitride Materials and Methods” filed on Dec. 14, 2000, which is incorporated herein by reference. It may be preferable for the overlying layer to have a single crystal structure. As noted above, in some embodiments, the thickness of the strain-absorbing layer is controlled so that the overlying layer has an epitaxial relationship with the substrate. It may be advantageous for the overlying layer to have a single crystal structure because it facilitates formation of a single crystal, high quality gallium nitride material region. In some embodiments, the overlying layer has a different crystal structure than the substrate. It should also be understood that the overlying layer may not have a single crystal structure and may be amorphous or polycrystalline, though all of the advantages associated with the single crystal overlying layers may not be achieved. The overlying layer may have any suitable thickness. For example, the overlying layer may be between about 10 nanometers and 5 microns, though other thicknesses are also possible. In the illustrative embodiment, transition layer 16 is formed directly on the overlying layer. In certain embodiments, such as when the overlying layer has a constant composition, it may be preferred for the transition layer to be formed of a compositionally-graded material (e.g., a compositionally-graded nitride-based material). Suitable compositionally-graded layers have been described in commonly-owned U.S. Pat. No. 6,649,287 which is incorporated by reference above. Compositionally-graded transition layers have a composition that is varied across at least a portion of the layer. Compositionally-graded transition layers are particularly effective in reducing crack formation in gallium nitride material regions formed on the transition layer by lowering thermal stresses that result from differences in thermal expansion rates between the gallium nitride material and the substrate (e.g., silicon). According to one set of embodiments, the transition layer is compositionally-graded and formed of an alloy of gallium nitride such as AlxInyGa(1-x-y)N, AlxGa(1-x)N, and InyGa(1-y)N. In these embodiments, the concentration of at least one of the elements (e.g., Ga, Al, In) of the alloy is varied across at least a portion of the thickness of the transition layer. When transition layer 16 has an AlxInyGa(1-x-y)N composition, x and/or y may be varied. When the transition layer has a AlxGa(1-x)N composition, x may be varied. When the transition layer has a InyGa(1-y)N composition, y may be varied. In certain preferred embodiments, it is desirable for the transition layer to have a low gallium concentration at a back surface which is graded to a high gallium concentration at a front surface. It has been found that such transition layers are particularly effective in relieving internal stresses within gallium nitride material region 18. For example, the transition layer may have a composition of AlxGa(1-x)N, where x is decreased from the back surface to the front surface of the transition layer (e.g., x is decreased from a value of 1 at the back surface of the transition layer to a value of 0 at the front surface of the transition layer). In one preferred embodiment, structure 10 includes an aluminum nitride overlying layer 15 and a compositionally-graded transition layer 16. The compositionally-graded transition layer may have a composition of AlxGa(1-x)N, where x is graded from a value of 1 at the back surface of the transition layer to a value of 0 at the front surface of the transition layer. The composition of the transition layer, for example, may be graded discontinuously (e.g., step-wise) or continuously. One discontinuous grade may include steps of AlN, Al0.6Ga0.4N and Al0.3Ga0.7N proceeding in a direction toward the gallium nitride material region. It should be understood that, in other cases, transition layer 16 may have a constant composition and may not be compositionally-graded (e.g., when the overlying layer is compositionally-graded). It should also be understood that in some embodiments of the invention, as shown in FIG. 2, a separate transition layer is not present between the overlying layer and the gallium nitride material region. In the illustrative embodiment of FIG. 2, structure 20 includes overlying layer 15 formed directly on top of strain-absorbing layer 12 and gallium nitride material region 18 formed directly on the overlying layer. In this embodiment, it may be preferable for the overlying layer to be compositionally-graded as described above. The overlying layer and/or transition layer are typically (though not always) not part of the active region of the device. As described above, the overlying layer and/or transition layer may be formed to facilitate deposition of gallium nitride material region 18. However, in some cases, the overlying layer and/or transition layer may have other functions including functioning as a heat spreading layer that helps remove heat from active regions of the semiconductor structure during operation of a device. For example, such transition layers that function as heat spreading layers have been described in commonly-owned, co-pending U.S. patent application Ser. No. 09/792,409 entitled “Gallium Nitride Materials Including Thermally-Conductive Regions,” filed Feb. 23, 2001, which is incorporated herein by reference. Active regions of the device may be formed in gallium nitride material region 18. Gallium nitride material region 18 comprises at least one gallium nitride material layer. As used herein, the phrase “gallium nitride material” refers to gallium nitride (GaN) and any of its alloys, such as aluminum gallium nitride (AlxGa(1-x)N), indium gallium nitride (InyGa(1-y)N), aluminum indium gallium nitride (AlxInyGa(1-x-y)N), gallium arsenide phosporide nitride (GaAsaPbN(1-a-b)), aluminum indium gallium arsenide phosporide nitride (AlxInyGa(1-x-y)AsaPbN(1-a-b)), amongst others. Typically, when present, arsenic and/or phosphorous are at low concentrations (i.e., less than 5 weight percent). In certain preferred embodiments, the gallium nitride material has a high concentration of gallium and includes little or no amounts of aluminum and/or indium. In high gallium concentration embodiments, the sum of (x+y) may be less than 0.4, less than 0.2, less than 0.1, or even less. In some cases, it is preferable for the gallium nitride material layer to have a composition of GaN (i.e., x+y=0). Gallium nitride materials may be doped n-type or p-type, or may be intrinsic. Suitable gallium nitride materials have been described in U.S. Pat. No. 6,649,287, incorporated by reference above. In some cases, gallium nitride material region 18 includes only one gallium nitride material layer. In other cases, gallium nitride material region 18 includes more than one gallium nitride material layer. For example, the gallium nitride material region may include multiple layers (e.g., 18a, 18b, 18c) as shown in FIG. 4. In certain embodiments, it may be preferable for the gallium nitride material of layer 18b to have an aluminum concentration that is greater than the aluminum concentration of the gallium nitride material of layer 18a. For example, the value of x in the gallium nitride material of layer 18b (with reference to any of the gallium nitride materials described above) may have a value that is between 0.05 and 1.0 greater than the value of x in the gallium nitride material of layer 18a, or between 0.05 and 0.5 greater than the value of x in the gallium nitride material of layer 18a. For example, layer 18b may be formed of Al0.26Ga0.74N, while layer 18a is formed of GaN. This difference in aluminum concentration may lead to formation of a highly conductive region at the interface of the layers 18b, 18a (i.e., a 2-D electron gas region). In the illustrative embodiment, layer 18c may be formed of GaN. Suitable gallium nitride material layer arrangements have been described, for example, in commonly-owned, co-pending U.S. patent application Ser. No. 10/740,376 entitled “Gallium Nitride Material Devices Including an Electrode-Defining Layer and Methods of Forming the Same,” filed Dec. 17, 2003 which is incorporated herein by reference. Gallium nitride material region 18 also may include one or more layers that do not have a gallium nitride material composition such as other III-V compounds or alloys, oxide layers, and metallic layers. Gallium nitride material region 18 is of high enough quality so as to permit the formation of devices therein. As noted above, the presence of the strain-absorbing layer may reduce the misfit dislocation density in the overlying layer which can reduce formation of defects in the gallium nitride material region. For example, the generation of point defects, line defects, and planar defects may be reduced. By limiting defect generation in the gallium nitride material region, device performance can be improved. The low misfit dislocation densities can also limit creation of electronic states within energy bands of the gallium nitride material regions which also negatively effect device performance. Preferably, gallium nitride material region 18 also has a low crack level. As described above, the transition layer (particularly when compositionally-graded) and/or overlying layer may reduce crack formation. Gallium nitride materials having low crack levels have been described in U.S. Pat. No. 6,649,287 incorporated by reference above. In some cases, the gallium nitride material region has a crack level of less than 0.005 μm/μm2. In some cases, the gallium nitride material region has a very low crack level of less than 0.001 μm/μm2. In certain cases, it may be preferable for the gallium nitride material region to be substantially crack-free as defined by a crack level of less than 0.0001 μm/μm2. In certain cases, gallium nitride material region 18 includes a layer (or layers) which have a single crystal (i.e., monocrystalline) structure. In some cases, the gallium nitride material region includes one or more layers having a Wurtzite (hexagonal) structure. The thickness of gallium nitride material region 18 and the number of different layers are dictated, at least in part, by the requirements of the specific device. At a minimum, the thickness of the gallium nitride material region is sufficient to permit formation of the desired structure or device. The gallium nitride material region generally has a thickness of greater than 0.1 micron, though not always. In other cases, gallium nitride material region 18 has a thickness of greater than 0.5 micron, greater than 2.0 microns, or even greater than 5.0 microns. As described above, in certain preferred embodiments, substrate 14 is a silicon substrate. As used herein, a silicon substrate refers to any substrate that includes a silicon surface. Examples of suitable silicon substrates include substrates that are composed entirely of silicon (e.g., bulk silicon wafers), silicon-on-insulator (SOI) substrates, silicon-on-sapphire substrate (SOS), and SIMOX substrates, amongst others. Suitable silicon substrates also include substrates that have a silicon wafer bonded to another material such as diamond, AlN, or other polycrystalline materials. Silicon substrates having different crystallographic orientations may be used, though single crystal silicon substrates are preferred. In some cases, silicon (111) substrates are preferred. In other cases, silicon (100) substrates are preferred. It should be understood that other types of substrates may also be used including sapphire, silicon carbide, indium phosphide, silicon germanium, gallium arsenide, gallium nitride, aluminum nitride, or other III-V compound substrates. However, in embodiments that do not use silicon substrates, all of the advantages associated with silicon substrates may not be achieved. In some embodiments, it may be preferable to use non-nitride material-based substrates such as silicon, sapphire, silicon carbide, indium phosphide, silicon germanium and gallium arsenide. Substrate 14 may have any suitable dimensions and its particular dimensions are dictated by the application. Suitable diameters include, but are not limited to, about 2 inches (50 mm), 4 inches (100 mm), 6 inches (150 mm), and 8 inches (200 mm). Advantageously, the strain-absorbing layer may be used to form a high quality gallium nitride material region on substrates (e.g., silicon substrates) over a variety of thicknesses. In some cases, it may be preferable for the substrate to be relatively thick, such as greater than about 125 micron (e.g., between about 125 micron and about 800 micron, or between about 400 micron and 800 micron). Relatively thick substrates may be easy to obtain, process, and can resist bending which can occur, in some cases, in thinner substrates. In other embodiments, thinner substrates (e.g., less than 125 microns) are used, though these embodiments may not have the advantages associated with thicker substrates, but can have other advantages including facilitating processing and/or reducing the number of processing steps. In some processes, the substrate initially is relatively thick (e.g., between about 200 microns and 800 microns) and then is thinned during a later processing step (e.g., to less than 150 microns). In some preferred embodiments, the substrate is substantially planar in the final device or structure. Substantially planar substrates may be distinguished from substrates that are textured and/or have trenches formed therein (e.g., as in U.S. Pat. No. 6,265,289). As shown, the layers/regions of the device (e.g., strain-absorbing layer, overlying layer, transition layer, gallium nitride material region) may also be substantially planar in the final device or structure. As described further below, such layers/regions may be grown in vertical (e.g., non-lateral) growth processes. Planar substrates and layers/regions can be advantageous in some embodiments, for example, to simplify processing. Though it should be understood that, in some embodiments of the invention, lateral growth processes may be used as described further below. FIG. 3 illustrates a semiconductor structure 22 according to another embodiment of the invention. In this embodiment, strain-absorbing layer 12 is formed between layers within the structure, and is not formed directly on the substrate. For example, the strain-absorbing layer may be formed between an underlying layer 24 and an overlying layer 15. In this embodiment, the strain-absorbing layer may reduce the formation of misfit dislocations in overlying layer 15 as described above in connection with the embodiments of FIG. 1. Underlying layer 24 may be formed of a variety of semiconductor materials. In some embodiments, the underlying layer is formed of a nitride-based material. Suitable nitride-based materials include, but are not limited to, aluminum nitride-based materials (e.g., aluminum nitride, aluminum nitride alloys) and gallium nitride materials. In some embodiments, it may be preferred for the underlying material to have a different composition than the overlying material. The underlying layer may also have a different crystal structure than the overlying layer. In other embodiments, the underlying material may be formed of non-nitride based materials. The semiconductor structures illustrated in FIGS. 1-3 may form the basis of a variety of semiconductor devices. Suitable devices include, but are not limited to, transistors (e.g., FETs) as well as light-emitting devices including LEDs and laser diodes. The devices have active regions that are typically, at least in part, within the gallium nitride material region. Also, the devices include a variety of other functional layers and/or features (e.g., electrodes). The strain-absorbing layer may be included in structures and devices described in commonly-owned, co-pending U.S. patent application Ser. No. 10/740,376, incorporated by reference above. For example, FIG. 4 schematically illustrates a FET device 30 according to one embodiment of the invention which is similar to a FET device described in U.S. patent application Ser. No. 10/740,376 except device 30 includes strain-absorbing layer 12. Device 30 includes a source electrode 34, a drain electrode 36 and a gate electrode 38 formed on gallium nitride material region 18 (which includes a first layer 18b and a second layer 18a). The device also includes an electrode defining layer 40 which, as shown, is a passivating layer that protects and passivates the surface of the gallium nitride material region. A via 42 is formed within the electrode defining layer in which the gate electrode is, in part, formed. Strain-absorbing layer 12 is formed directly on the substrate and overlying layer 15 is formed directly on the strain-absorbing layer. In some embodiments, the overlying layer is compositionally-graded. In some embodiments, the overlying layer may have a constant composition (e.g., aluminum nitride or an aluminum nitride alloy) and a compositionally-graded transition layer is formed on the strain-absorbing layer. The strain-absorbing layer may also be included in structures and devices described in U.S. Pat. No. 6,649,287 which is incorporated herein by reference above. The strain-absorbing layer may also be included in structures and devices described in commonly-owned U.S. Pat. No. 6,611,002 entitled “Gallium Nitride Material Devices and Methods Including Backside Vias” which is incorporated herein by reference. It should be understood that other structures and devices that use the strain-absorbing layer may be within the scope of the present invention including structures and devices that are not specifically described herein. Other structures may include other layers and/or features, amongst other differences. Semiconductor structure 10 may be manufactured using known semiconductor processing techniques. In embodiments in which the strain-absorbing layer is a silicon nitride-based material (e.g., amorphous SiN), the strain-absorbing layer may be formed by nitridating a top surface of the silicon substrate as noted above. In a nitridation process, nitrogen reacts with a top surface region of the silicon substrate to form a silicon nitride-based layer. The top surface may be nitridated by exposing the silicon substrate to a gaseous source of nitrogen at elevated temperatures. For example, ammonia may be introduced into a reaction chamber in which a silicon substrate is positioned. The temperature in the reaction chamber may be between about 1000° C. and about 1100° C. and the pressure may be between about 20 torr and about 40 torr (in some cases, about 30 torr). The reaction between nitrogen and the silicon substrate is allowed to proceed for a reaction time selected to produce a layer having a desired thickness. It should be understood that other processes may be used to form silicon nitride-based strain-absorbing layers including processes (e.g., CVD processes) that use separate nitrogen and silicon sources. Also, when the strain-absorbing layer is formed of another type of material (non-silicon nitride-based material), other deposition processes known in the art are used. In some embodiments, the strain-absorbing layer may be formed in-situ with the overlying layer (and, in some cases, subsequent layers) of the structure. That is, the strain-absorbing layer may be formed during the same deposition step as the overlying layer (and, in some cases, subsequent layers). In processes that grow a silicon nitride-based material strain-absorbing layer by introducing a nitrogen source (e.g., ammonia) into a reaction chamber as described above, a second source gas may be introduced into the chamber after a selected time delay after the nitrogen source. The second source reacts with the nitrogen source to form the overlying layer, thus, ending growth of the strain-absorbing layer. For example, when the overlying layer is formed of aluminum nitride, an aluminum source (e.g., trimethylaluminum) is introduced into the chamber at a selected time after the nitrogen source (e.g., ammonia). The time delay is selected so that the strain-absorbing layer grows to a desired thickness. The reaction between the second source (e.g., aluminum source) and the nitrogen source is allowed to proceed for a sufficient time to produce the overlying layer. When the overlying layer has a single crystal structure, the reaction conditions are selected appropriately. For example, the reaction temperature may be greater than 700° C., such as between about 1000° C. and about 1100° C. In some cases, lower growth temperatures may be used including temperatures between about 500° C. and about 600° C. It should also be understood that the strain-absorbing layer may be formed in a separate process than the overlying layer and subsequent layers. For example, the strain-absorbing layer may be formed on the substrate in a first process. Then, at a later time, the overlying layers may be formed on the strain-absorbing layer in a second process. In the processes described above, the overlying layer is grown in a vertical growth process. That is, the overlying layer is grown in a vertical direction with respect to the strain-absorbing layer. The ability to vertically grow the strain-absorbing layer having low misfit dislocation densities may be advantageous as compared to lateral growth processes which may be more complicated. Transition layer 16 and gallium nitride material region 18 may also be grown in the same deposition step as the overlying layer and the strain-absorbing layer. In such processes, suitable sources are introduced into the reaction chamber at appropriate times. Suitable MOCVD processes to form compositionally-graded transition layers and gallium nitride material region over a silicon substrate have been described in U.S. Pat. No. 6,649,287 incorporated by reference above. When gallium nitride material region 18 has different layers, in some cases, it is preferable to use a single deposition step to form the entire region 18. When using the single deposition step, the processing parameters may be suitably changed at the appropriate time to form the different layers. It should also be understood that the transition layer and the gallium nitride material region may be grown separately from the strain-absorbing layer and overlying layer. The gallium nitride material region and transition layer may be grown in a vertical growth process. That is, these regions are grown in a vertical direction with respect to underlying layers. The ability to vertically grow the gallium nitride material region having low misfit dislocation densities may be advantageous as compared to lateral growth processes which may be more complicated. However, in other embodiments of the invention (not shown), it is possible to grow, at least a portion of, gallium nitride material region 18 using a lateral epitaxial overgrowth (LEO) technique that involves growing an underlying gallium nitride layer through mask openings and then laterally over the mask to form the gallium nitride material region, for example, as described in U.S. Pat. No. 6,051,849. In other embodiments of the invention (not shown), it is possible to grow the gallium nitride material region 18 using a pendeoepitaxial technique that involves growing sidewalls of gallium nitride material posts into trenches until growth from adjacent sidewalls coalesces to form a gallium nitride material region, for example, as described in U.S. Pat. No. 6,265,289. In these lateral growth techniques, gallium nitride material regions with very low defect densities are achievable. For example, at least a portion of the gallium nitride material region may have a defect density of less than about 105 defects/cm2. Commonly-owned, co-pending U.S. patent application Ser. No. 10/740,376, incorporated by reference above, further describes techniques used to grow other layers and features shown in the embodiment of FIG. 4. It should also be understood that other processes may be used to form structures and devices of the present invention as known to those of ordinary skill in the art. The following examples are meant to be illustrative and is not limiting. EXAMPLE 1 This example illustrates the formation of a silicon nitride-based material strain-absorbing layer on a silicon substrate according to one embodiment of the present invention. A 100 mm silicon substrate was placed in a reaction chamber. Ammonia gas was introduced into the chamber as a nitrogen source. The temperature was maintained at 1030° C. and the pressure at about 30 torr. A layer of amorphous silicon nitride (SiN) was formed. About 6 seconds after the introduction of ammonia, TMA was introduced into the chamber as an aluminum source. The temperature and pressure were respectively maintained at 1030° C. and about 30 torr. Growth proceeded for 30 minutes. FIGS. 5-7 are copies of micrograph images that illustrate the resulting structure. FIG. 5 is a copy of a STEM (scanning transmission electron microscope) image. FIGS. 6 and 7 are copies of high-resolution TEM images. The images show the presence of an amorphous silicon nitride strain-absorbing layer formed between a single crystal aluminum nitride layer and a single crystal silicon substrate. In particular, the high-resolution TEM images show the crystal structures of the resulting layers and substrate. The images show that the crystal structure of the silicon nitride layer is amorphous, the crystal structure of the silicon substrate is cubic and the crystal structure of the aluminum nitride is hexagonal. The aluminum nitride layer has an epitaxial relationship with the substrate. The images also show the absence of misfit dislocations at (or near) the interface of the amorphous silicon nitride strain-absorbing layer and the aluminum nitride layer. This example establishes that strain-absorbing layers of the present invention may be used to limit misfit dislocation density. Comparative Example This example illustrates the presence of misfit dislocations in an aluminum nitride layer formed directly on a silicon substrate in the absence of a strain-absorbing layer of the present invention. FIG. 8 is a copy of an image published in R. Liu, et. al., Applied Phys. Lett. 83(5), 860 (2003). The image illustrates an aluminum nitride layer formed directly on a silicon substrate, without the presence of a silicon nitride strain-absorbing layer, following procedures described in the article. Misfit dislocations are indicated by “”. The interface coherence is indicated by solid lines that connect {111}Si and {1-100}AlN lattice planes. Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.
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<SOH> BACKGROUND OF INVENTION <EOH>Gallium nitride materials include gallium nitride (GaN) and its alloys such as aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), and aluminum indium gallium nitride (AlInGaN). These materials are semiconductor compounds that have a relatively wide, direct bandgap which permits highly energetic electronic transitions to occur. Such electronic transitions can result in gallium nitride materials having a number of attractive properties including the ability to efficiently emit blue light, the ability to transmit signals at high frequency, and others. Accordingly, gallium nitride materials are being widely investigated in many microelectronic applications such as transistors, field emitters, and optoelectronic devices. In many applications, gallium nitride materials are grown on a substrate. However, differences in the properties between gallium nitride materials and substrates can lead to difficulties in growing layers suitable for many applications. For example, gallium nitride (GaN) has a different thermal expansion coefficient (i.e., thermal expansion rate) and lattice constants than many substrate materials including sapphire, silicon carbide and silicon. This differences in thermal expansion and lattice constants may lead to formation of defects including misfit dislocations. Misfit dislocations may have a number of negative effects including degrading overlying semiconductor material regions when the dislocations propagate to those regions, creation of electronic states within energy bands of those regions that negatively effect device performance, and promoting formation of other types of crystal defects (e.g., point defects, line defects and planar defects). These effects can negatively impact device performance.
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<SOH> SUMMARY OF INVENTION <EOH>The invention provides semiconductor structures including structures that comprise a gallium nitride material region and a strain-absorbing layer, as well as methods associated with the same. In one embodiment, a semiconductor structure is provided. The structure comprises a silicon substrate having a top surface; and, an amorphous silicon nitride-based material layer covering a majority of the top surface of the substrate. A nitride-based material overlying layer is formed on the silicon nitride-based material layer. In another embodiment, a semiconductor structure is provided. The structure comprises a silicon substrate including a top surface; and, a silicon nitride-based material layer having a thickness of less than 100 Angstroms and covering a majority of the top surface of the substrate. A single crystal nitride-based material overlying layer is formed on the silicon nitride-based material layer. In another embodiment, a semiconductor structure is provided. The structure comprises a silicon substrate including a top surface; and, an amorphous silicon nitride-based material layer covering substantially the entire top surface of the silicon substrate and having a thickness of less than 100 Angstroms. A compositionally-graded transition layer is formed on the amorphous silicon nitride-based material layer. A gallium nitride material region is formed on the transition layer. In another embodiment, a semiconductor structure is provided. The structure comprises a semiconductor material region; and, a strain-absorbing layer formed on the semiconductor material region. A nitride-based material layer is formed directly on the strain-absorbing layer, wherein the misfit dislocation density in the nitride-based material layer is less than about 10 10 defects/cm 2 . In another embodiment, a method of forming a semiconductor structure is provided. The method comprises providing a silicon substrate in a reaction chamber; and, introducing a nitrogen source into the reaction chamber to form an amorphous silicon nitride-based material layer. The method further comprises introducing a second source into the reaction chamber to form a nitride-based material overlying layer on the silicon nitride-based material layer. Other aspects, embodiments and features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. The accompanying figures are schematic and are not intended to be drawn to scale. In the figures, each identical, or substantially similar component that is illustrated in various figures is represented by a single numeral or notation. For purposes of clarity, not every component is labeled in every figure. Nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. All patent applications and patents incorporated herein by reference are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.
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20051229
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86613.0
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TRAN, TAN N
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GALLIUM NITRIDE MATERIALS AND METHODS ASSOCIATED WITH THE SAME
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ACCEPTED
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10,879,724
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ACCEPTED
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Adaptive de-interlacing method and apparatus based on phase corrected field, and recording medium storing programs for executing the adaptive de-interlacing method
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There is disclosed an adaptive de-interlacing method and apparatus based on a phase corrected field of an input interlaced picture signal, and a recording medium storing computer programs for executing the method. The method includes: generating a phase corrected kth field by compensating a phase of the kth field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected kth field and the (k−1)th field of the interlaced picture signal; calculating a second motion vector between the (k−1)th field and the (k+1)th field of the interlaced picture signal; and determining whether there is motion of the input picture based on the first and second motion vector values, and generating a kth progressive frame based on the result and the kth field. Thus, a serration phenomenon is minimized after de-interlacing by more exactly detecting the motion information of a corresponding inserted field.
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1. An adaptive de-interlacing method based on a phase corrected field of an input interlaced picture signal comprising: generating a phase corrected kth field of the input interlaced picture signal by compensating a phase of the kth field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected kth field and a (k−1)th field of the interlaced picture signal; calculating a second motion vector between the (k−1)th field and a (k+1)th field of the interlaced picture signal; and determining whether there is motion of an input picture based on the first and second motion vector values, and generating a kth progressive frame based on a result of the motion determination and the kth field, where k comprises an integer. 2. The method of claim 1, wherein if one of the first and second motion vector values is larger than a predetermined critical value, it is determined that there is motion of the input picture, and then, a kth progressive frame is generated by using the phase corrected kth field and the kth field. 3. The method of claim 1, wherein if the first and second motion vector values are smaller than the predetermined critical value, it is determined that there is no motion of the input picture, and then, a kth progressive frame is generated by using the (k−1)th field and the kth field. 4. The method of claim 1, further comprising: generating an adaptive motion vector based on the first and second motion vectors. 5. The method of claim 4, wherein if the first motion vector is (dx1, dy1) and the second motion vector is (dx2, dy2), the adaptive motion vector is (dx2/w, dy2/w), where w = dx1 2 + dy1 2 dx2 2 + dy2 2 6. The method of claim 4, further comprising: generating an adaptive motion compensated field based on the generated adaptive motion vector, the (k−1)th field, and the (k+1)th field. 7. The method of claim 4, wherein a correlation between the first and second motion vectors is calculated, and then, if the calculated correlation is larger than a predetermined critical value, a progressive frame is generated by using the adaptive motion vector. 8. The method of claim 1, wherein if the kth field is an odd field, the phase corrected kth field is an even field, and if the kth field is an even field, the phase corrected k h field is an odd field. 9. An adaptive de-interlacing apparatus based on a phase corrected field of an input interlaced picture signal, comprising: a phase corrector, which generates a phase corrected kth field by compensating a phase of a kth field of the input interlaced picture signal by 1 line frequency; a first motion vector calculator, which calculates a first motion vector between the phase corrected kth field and a (k−1)th field of the input interlaced picture signal; a second motion vector calculator, which calculates a second motion vector between the (k−1)th field and a (k+1)th field of the input interlaced picture signal; and a picture converter, which determines whether there is motion of an input picture based on the first and second motion vector values, and generates a kth progressive frame based on a result of the motion determination and the kth field, where k comprises an integer. 10. The apparatus of claim 9, wherein if one of the first and second motion vector values is larger than a predetermined critical value, the picture converter determines that there is motion of the input picture, and then generates a kth progressive frame by using the phase corrected kth field and the kth field. 11. The apparatus of claim 9, wherein if the first and second motion vector values are smaller than a predetermined critical value, the picture converter determines that there is no motion of the input picture, and then, generates a kth progressive frame by using the (k−1)th field and the kth field. 12. The apparatus of claim 9, further comprising: an adaptive motion vector calculating and motion compensating unit which calculates an adaptive motion vector based on the first and second motion vectors, and then, generates an adaptive motion compensated field by using the calculated adaptive motion vector, the (k−1)th field, and the (k+1)th field. 13. The apparatus of claim 12, wherein if the first motion vector is (dx1, dy1) and the second motion vector is (dx2, dy2), the adaptive motion vector is (dx2/w, dy2/w), where w = dx1 2 + dy1 2 dx2 2 + dy2 2 . 14. The apparatus of claim 12, wherein if there is motion of the input picture and the correlation between the first and second motion vectors is larger than a predetermined critical value, the picture converter generates a kth progressive frame by using the kth field and the adaptive motion compensated field. 15. The apparatus of claim 9, wherein if the kth field is an odd field, the phase corrected kth field is an even field, and if the kth field is an even field, the phase corrected kth field is an odd field. 16. A computer readable medium storing computer programs for executing an adaptive de-interlacing method based on a phase corrected field of an input interlaced picture signal, the method comprising: generating a phase corrected kth field by compensating a phase of the kth field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected kth field and a (k−1)th field of the interlaced picture signal; calculating a second motion vector between the (k−1)th field and a (k+1)th field of the interlaced picture signal; and determining whether there is motion of an input picture based on the first and second motion vector values, and generating a kth progressive frame based on a result of the motion determination and the kth field, where k comprises an integer. 17. The medium of claim 16, wherein if one of the first and second motion vector values is larger than a predetermined critical value, it is determined that there is motion of the input picture, and then, a kth progressive frame is generated by using the phase corrected kth field and the kth field. 18. The medium of claim 16, wherein if the first and second motion vector values are smaller than a predetermined critical value, it is determined that there is no motion of the input picture, and then, a kth progressive frame is generated by using the (k−1)th field and the kth field. 19. The medium of claim 16, further comprising: generating an adaptive motion vector based on the first and second motion vectors. 20. The medium of claim 19, wherein if the first motion vector is (dx1, dy1) and the second motion vector is (dx2, dy2), the adaptive motion vector is (dx2/w, dy2/w), where w = dx1 2 + dy1 2 dx2 2 + dy2 2 . 21. The medium of claim 19, further comprising: generating an adaptive motion compensated field based on the generated adaptive motion vector, the (k−1)th field and the (k+1)th field. 22. The medium of claim 19, wherein a correlation between the first and second motion vectors is calculated, and then, if the calculated correlation is larger than a predetermined critical value, a progressive frame is generated by using the adaptive motion vector. 23. The medium of claim 16, wherein if the kth field is an odd field, the phase corrected kth field is an even field, and if the kth field is an even field, the phase corrected kth field is an odd field.
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BACKGROUND OF THE INVENTION This application claims the priority of Korean Patent Application No. 2003-53888, filed on Aug. 4, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 1. Field of the Invention The present invention relates to an apparatus for and a method of converting a picture format, and more particularly, to an adaptive de-interlacing apparatus and method based on a phase corrected field corresponding to a predetermined interlaced field by which an input interlaced picture signal is converted into a progressive picture signal. 2. Description of the Related Art A general television picture signal is compressed in the frequency domain using an interlacing method to form one frame with two fields. However, lately, a picture is commonly displayed on a personal computer (PC) and a high definition television (HDTV) using a progressive method. Therefore, to display an interlaced picture, a progressive scanning should be performed to generate picture lines, which are omitted in the interlaced picture, with an optional method. This is realized using a de-interlacing method. FIG. 1 is a drawing to describe a conventional video data de-interlacing method. With reference to FIG. 1, during de-interlacing, a field including only all vertically odd or even samples is converted into a frame. At this time, an output frame F0({right arrow over (x)},n) is defined by Equation, 1. F 0 ( x -> , n ) = { F ( x -> , n ) ( y mod 2 = n mod 2 ) , F i ( x -> , n ) otherwise [ Equation 1 ] where {right arrow over (x)} denotes a spatial position, and n is a field number. Also, F({overscore (x)},n) is an input field, and Fi({right arrow over (x)},n) is an interpolated pixel. FIG. 2 shows a conventional de-interlacing method based on motion compensation. In this method, motion information of a picture is extracted to interpolate vacant lines of a present field, and then the vacant lines of the present field are interpolated using pixels of a preceding field or a next preceding field based on the extracted motion information. In the de-interlacing method based on an MC, it is assumed that a motion vector between adjacent even parity fields or adjacent odd parity fields has uniform velocity, and then a field is inserted in the middle position between two adjacent even or odd parity fields. The video line interpolating method using an MC is disclosed in U.S. Pat. No. 6,233,018. However, since a moving picture does not always have the uniform velocity, and the position of an inserted field is not right middle position between two adjacent fields with the same phase, a serration phenomenon appears, which degrades the quality of the moving picture. SUMMARY OF THE INVENTION The present invention provides an adaptive de-interlacing method and apparatus to exactly detect motion information and minimize a serration phenomenon after de-interlacing, by using a phase corrected field which corrects a phase of a corresponding inserted field for converting an input interlaced picture signal to a progressive signal, and also provides a recording medium storing computer programs for executing the method. According to an aspect of the present invention, there is provided an adaptive de-interlacing method based on a phase corrected field of an input interlaced picture signal, including: generating a phase corrected kth field by compensating a phase of the kth field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected kth field and the (k−1)th field of the interlaced picture signal; calculating a second motion vector between the (k−1)th field and the (k+1)th field of the interlaced picture signal; and determining whether there is motion of the input picture based on the first and second motion vector values, and generating a kth progressive frame based on the result and the kth field. Also, the method may further include: generating an adaptive motion vector based on the first and second motion vectors; generating an adaptive motion compensated field based on the generated adaptive motion vector, the (k−1)th field, and the (k+1)th field; and calculating a correlation between the first and second motion vectors, and if the calculated correlation is larger than the critical value, generating a progressive frame based on the adaptive motion vector. According to another aspect of the present invention, there is provided an adaptive de-interlacing apparatus based on a phase corrected field of an input interlaced picture signal, including: a phase corrector, which generates a phase corrected kth field by compensating a phase of the kth field of the input interlaced picture signal by 1 line frequency; a first motion vector calculator, which calculates a first motion vector between the phase corrected kth field and the (k−1)th field of the interlaced picture signal; a second motion vector calculator which calculates a second motion vector between the (k−1)th field and the (k+1)th field of the interlaced picture signal; and a picture converter, which determines whether there is motion of the input picture based on the first and second motion vector values, and generates a kth progressive frame based on the result and the kth field. According to another aspect of the present invention, there is provided a recording medium storing computer programs for executing an adaptive de-interlacing method based on a phase corrected field of an input interlaced picture signal, the method including: generating a phase corrected kth field by compensating a phase of the kth field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected kth field and the (k−1)th field of the interlaced picture signal; calculating a second motion vector between the (k−1)th field and the (k+1)th field of the interlaced picture signal; and determining whether there is motion of the input picture based on the first and second motion vector values, and generating a kth progressive frame based on the result and the kth field. BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: FIG. 1 is a drawing to describe a conventional video data de-interlacing method; FIG. 2 shows a conventional de-interlacing method based on motion compensation; FIG. 3 is a block diagram of an adaptive de-interlacing apparatus according to an embodiment of the present invention; FIG. 4 shows a phase correction procedure of a kth field and a calculation procedure of a motion vector between the phase corrected kth field and a (k−1)th field, according to the present invention; FIG. 5 is a flowchart of an adaptive de-interlacing method according to an embodiment of the present invention; FIG. 6 is a block diagram of an adaptive de-interlacing apparatus according to another embodiment of the present invention; FIG. 7 shows an adaptive motion vector calculation procedure and an adaptive motion compensation procedure, according to the present invention; and FIG. 8 is a flowchart of an adaptive de-interlacing method according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 3 is a block diagram of an adaptive de-interlacing apparatus according to the present invention. With reference to FIG. 3, the de-interlacing apparatus according to the present invention converts an input interlaced picture signal to a progressive picture signal, and includes a first field memory 310, a second field memory 320, a phase corrector 330, a first motion vector calculator 340, a second motion vector calculator 350, and a picture converter 390. The picture converter 390 includes a motion detector 360, a selector 370, and an interleaving unit 380. A (k+1)th field of an interlaced picture signal is input to the first field memory 310, and the first field memory 310 and the second field memory 320 are used for generating a kth field and a (k−1)th field, respectively. The phase corrector 330 generates a phase corrected kth field by delaying an output of the first field memory 310, that is, a phase of a kth field by 1-horizontal period. When the kth field is an odd field, the phase corrected kth field is an even field opposite to the phase of the kth field. The first motion vector calculator 340 calculates a first motion vector MV1=(dx1, dy1) between the (k−1)th field, which is an output by the second field memory 320, and the phase corrected kth field, which is an output by the phase corrector 330, and then outputs the first motion vector to the motion detector 360. The second motion vector calculator 350 calculates a second motion vector MV2=(dx2, dy2) between an input (k+1)th field and a (k−1)th field, which is an output of the second field memory 320, and then outputs the second motion vector to the motion detector 360. The motion detector 360 determines whether there is motion of an input picture by comparing the first and second motion vector values respectively calculated in the first motion vector calculator 340 and second motion vector calculator 350 to a predetermined critical value, and then generates motion information according to the determined result, and finally outputs the motion information to the selector 370. In the present embodiment, if one of the first and second motion vector values is larger than a predetermined critical value, it is determined that there is motion of an input picture. Selectively, it is also possible to determine whether there is motion of an input picture by using one of the first and the second motion vectors. The selector 370 outputs one of the (k−1)th field from the second field memory 320 input based on the motion information input from the motion detector 360 and the phase corrected kth field from the phase corrector 330 to the interleaving unit 380. For example, when there is no motion of an input picture, the selector 370 outputs the (k−1)th field from the second field memory 320. Also, when there is motion of an input picture, the selector 370 outputs the phase corrected kth field from the phase corrector 330. The interleaving unit 380 generates and outputs a kth progressive frame based on the field signal input from the selector 370 and the kth field signal input from the first field memory 310. For example, if the kth field is an odd field and there is motion of an input picture, the interleaving unit 380 generates and outputs a progressive frame based on the kth field input from the first field memory 310 and the phase corrected kth field from the phase corrector 330, that is, the even fields. FIG. 4 shows a phase correction procedure of a kth field output from the first field memory 310, which is performed in the phase corrector 330 and the first motion vector calculator 340 shown in FIG. 3, and shows a calculation procedure of a motion vector between the phase corrected kth field and the (k−1)th field. FIG. 5 is a flowchart of an adaptive de-interlacing method performed in the adaptive de-interlacing apparatus shown in FIG. 3. A phase corrected kth field is generated in step 510 by correcting a phase of a kth field of an input interlaced picture signal by 1 line frequency. For example, if the kth field of the input interlaced picture signal is an odd field, the phase corrected kth field is an even field opposite to the phase of the kth field. A first motion vector between the phase corrected kth field generated in step 510 and the (k−1)th field of the input interlaced picture signal is calculated in step 520. A second motion vector between the (k−1)th field and (k+1)th field of the input interlaced picture signal is calculated in step 530. In step 540, it is determined whether there is motion of the input picture based on the calculated first and second motion vector values. In the present embodiment, if one of the first and second motion vector values is larger than a predetermined critical value, it is determined that there is motion of the input picture. Selectively, it is also possible to determine whether there is motion of the input picture by using one of the first and the second motion vectors. A kth progressive frame is generated in step 550 by using one of the (k−1)th field and the phase corrected kth field, according to whether there is motion of the input picture as determined in step 540. When the kth field is an odd field and there is no motion of the input picture, a progressive frame is generated and output in step 552 by using the kth field and the (k−1)th field which is an even field. When the kth field is an odd field and there is motion of the input picture, a progressive frame is generated and output in step 554 by using the kth field and the phase corrected kth field, that is, an even field. FIG. 6 is a block diagram of an adaptive de-interlacing apparatus according to another embodiment of the present invention. With reference to FIG. 6, a de-interlacing apparatus according to the present invention converts an input interlaced picture signal to a progressive picture signal, and includes a first field memory 610, a second field memory 620, a phase corrector 630, a first motion vector calculator 640, a second motion vector calculator 650, an adaptive motion vector calculating and motion compensating unit 670, and a picture converter 700. The picture converter 700 further includes a motion detector 660, a selector 680, and an interleaving unit 690. Since the first field memory 610, the second field memory 620, and the phase corrector 630 of FIG. 6 performs the same operation as the corresponding first field memory 310, second field memory 320, and phase corrector 330 of FIG. 3, detailed descriptions thereof will be omitted. The first motion vector calculator 640 calculates a first motion vector MV1=(dx1, dy1) between a (k−1)th field, which is an output of the second field memory 620, and a phase corrected kth field, which is an output of the phase corrector 630, and then outputs, the first motion vector to the motion detector 660 and the adaptive motion vector calculating and motion compensating unit 670. The second motion vector calculator 650 calculates a second motion vector MV2=(dx2, dy2) between an input (k+1)th field and a (k−1)th field, which is an output of the second field memory 620, and then outputs the second motion vector to the motion detector 660 and the adaptive motion vector calculating and motion compensating unit 670. The second motion vector calculator 650 also outputs the input (k+1)th field signal and the (k−1)th field signal, which is an output of the second field memory 620, to the adaptive motion vector calculating and motion compensating unit 670. The motion detector 660 determines whether there is motion of the input picture and whether the first and second motion vectors are valid, based on the input first and second motion vector values, generates motion information according to the determination result, and finally outputs the motion information to the selector 680. In the present embodiment, if one of the first and second motion vector values is larger than a predetermined critical value, it is determined that there is motion of the input picture. Selectively, it is also possible to determine whether there is motion of the input picture by using one of the first and second motion vectors. When it is determined that there is motion, by calculating the correlation between the first and second motion vectors, it is determined whether the first and second motion vectors are valid. In the present embodiment, if the correlation is larger than the predetermined critical value, it is determined that the first and second motion vectors are valid. The adaptive motion vector calculating and motion compensating unit 670 calculates an adaptive motion vector (dx2/w, dy2/w) based on the input first motion vector MV1=(dx1, dy1) and second motion vector MV2=(dx2, dy2), where w is calculated according to Equation 2. w = dx1 2 + dy1 2 dx2 2 + dy2 2 [ Equation 2 ] The adaptive motion vector calculating and motion compensating unit 670 generates an adaptive motion compensated field by performing a motion compensation based on the calculated adaptive motion vector and the input (k+1)th field and (k−1)th field information, and then outputs this to the selector 680. FIG. 7 shows an adaptive motion vector calculation and adaptive motion compensation method performed in the adaptive motion vector calculating and motion compensating unit 670. The selector 680 outputs one of the (k−1)th field from the second field memory 620, the phase corrected kth field from the phase corrector 630, and the adaptive motion compensated field from the adaptive motion vector calculating and motion compensating unit 670 to the interleaving unit 690 based on the motion information input from the motion detector 660. For example, if the motion information shows that there is no motion of the input picture, the selector 680 outputs the (k−1)th field from the second field memory 620. Also, if the motion information shows that there is motion of the input picture and the first and second motion vectors are not valid, the selector 680 outputs the phase corrected kth relative field from the phase corrector 630. Also, if the motion information shows that there is motion of the input picture and the first and second motion vectors are valid, the selector 680 outputs the adaptive motion compensated field input from the adaptive motion vector calculating and motion compensating unit 670. The interleaving unit 690 generates and outputs a kth progressive frame based on the field signal input from the selector 680 and the kth field signal input from the first field memory 610. For example, when the kth field is an odd field and there is no motion of the input picture, the interleaving unit 690 generates and outputs a kth progressive frame by using the kth field input from the first field memory 610 and the (k−1)th even field input from the second field memory 620. Also, when the kth field is an odd field and there is motion of the input picture and the first and second motion vectors are not valid, the interleaving unit 690 generates and outputs a kth progressive frame by using the kth field input from the first field memory 610 and the phase corrected kth field, which is an even field, input from the phase corrector 630. Also, when the kth field is an odd field and there is motion of the input picture and the first and second motion vectors are valid, the interleaving unit 690 generates and outputs a kth progressive frame by using the kth field input from the first field memory 610 and the adaptive motion compensated field, which is an even field, input from the adaptive motion vector calculating and motion compensating unit 670. FIG. 8 is a flowchart of an adaptive de-interlacing method performed in the de-interlacing apparatus shown in FIG. 6. A phase corrected kth field is generated in step 810 by correcting a phase of a kth field of an input picture signal by 1 line frequency. For example, if the kth field of the input interlaced picture signal is an odd field, the phase corrected kth field is an even field opposite to the phase of the kth field. A motion vector between the phase corrected kth field generated in step 810 and the (k−1)th field of the input interlaced picture signal, that is, a first motion vector MV1=(dx1, dy1) is calculated in step 820. A motion vector between the (k−1)th field and (k+1)th field of the input interlaced picture signal, that is, a second motion vector MV2=(dx2, dy2) is calculated in step 830. An adaptive motion vector (dx2/w, dy2/w) is calculated in step 840 based on the first motion vector MV1=(dx1, dy1) and the second motion vector MV2=(dx2, dy2), where w is calculated according to Equation 2. Also, an adaptive motion compensated field is generated by performing a motion compensation based on the calculated adaptive motion vector and the input (k+1)th field signal and (k−1)th field signal. In step 850, it is determined whether there is motion of the input picture and whether the first and second motion vectors are valid, based on the first and second motion vector values calculated in steps 820 and 830, and the motion information according to the determination result is also generated in step 850. In the present embodiment, if one of the first and second motion vector values is larger than a predetermined critical value, it is determined that there is motion of the input picture. Selectively, it is also possible to determine whether there is motion of the input picture by using one of the first and second motion vectors. When it is determined that there is motion, by calculating the correlation between the first and second motion vectors, it is determined whether the first and second motion vectors are valid. In the present embodiment, if the correlation is larger than the predetermined critical value, it is determined that the first and second motion vectors are valid. A kth progressive frame is generated in step 860 by using the kth field and one of the (k−1)th field, the phase corrected kth field, and the adaptive motion compensated field, based on the motion information generated in step 850. When the kth field is an odd field and there is no motion of the input picture, a kth progressive frame is generated in step 862 by using the kth field and the (k−1)th field which is an even field. When the kth field is an odd field and there is motion of the input picture and the first and second motion vectors are not valid, a kth progressive frame is generated in step 864 by using the kth field and the phase corrected kth field which is an even field. When the kth field is an odd field and there is motion of the input picture and the first and second motion vectors are valid, a kth progressive frame is generated in step 866 by using the kth field and the adaptive motion compensated field which is an even field. The present invention may be embodied in a general-purpose computer by running a program from a computer readable medium, including but not limited to storage media such as magnetic storage media (ROMs, RAMs, floppy disks, magnetic tapes, etc.), optically readable media (CD-ROMs, DVDs, etc.), and carrier waves (transmission over the internet). The present invention may be embodied as a computer readable medium having stored thereon a computer readable program code unit that can be executed by computer systems connected via a network during distributed processing. As described above, according to the present invention, it is possible to minimize the serration phenomenon after de-interlacing by detecting motion of an input picture based on a phase corrected field which corrects a phase of a corresponding inserted field, and also by more exactly detecting the motion information of a corresponding inserted field. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>This application claims the priority of Korean Patent Application No. 2003-53888, filed on Aug. 4, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 1. Field of the Invention The present invention relates to an apparatus for and a method of converting a picture format, and more particularly, to an adaptive de-interlacing apparatus and method based on a phase corrected field corresponding to a predetermined interlaced field by which an input interlaced picture signal is converted into a progressive picture signal. 2. Description of the Related Art A general television picture signal is compressed in the frequency domain using an interlacing method to form one frame with two fields. However, lately, a picture is commonly displayed on a personal computer (PC) and a high definition television (HDTV) using a progressive method. Therefore, to display an interlaced picture, a progressive scanning should be performed to generate picture lines, which are omitted in the interlaced picture, with an optional method. This is realized using a de-interlacing method. FIG. 1 is a drawing to describe a conventional video data de-interlacing method. With reference to FIG. 1 , during de-interlacing, a field including only all vertically odd or even samples is converted into a frame. At this time, an output frame F 0 ({right arrow over (x)},n) is defined by Equation, 1. F 0 ( x -> , n ) = { F ( x -> , n ) ( y mod 2 = n mod 2 ) , F i ( x -> , n ) otherwise [ Equation 1 ] where {right arrow over (x)} denotes a spatial position, and n is a field number. Also, F({overscore (x)},n) is an input field, and F i ({right arrow over (x)},n) is an interpolated pixel. FIG. 2 shows a conventional de-interlacing method based on motion compensation. In this method, motion information of a picture is extracted to interpolate vacant lines of a present field, and then the vacant lines of the present field are interpolated using pixels of a preceding field or a next preceding field based on the extracted motion information. In the de-interlacing method based on an MC, it is assumed that a motion vector between adjacent even parity fields or adjacent odd parity fields has uniform velocity, and then a field is inserted in the middle position between two adjacent even or odd parity fields. The video line interpolating method using an MC is disclosed in U.S. Pat. No. 6,233,018. However, since a moving picture does not always have the uniform velocity, and the position of an inserted field is not right middle position between two adjacent fields with the same phase, a serration phenomenon appears, which degrades the quality of the moving picture.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides an adaptive de-interlacing method and apparatus to exactly detect motion information and minimize a serration phenomenon after de-interlacing, by using a phase corrected field which corrects a phase of a corresponding inserted field for converting an input interlaced picture signal to a progressive signal, and also provides a recording medium storing computer programs for executing the method. According to an aspect of the present invention, there is provided an adaptive de-interlacing method based on a phase corrected field of an input interlaced picture signal, including: generating a phase corrected k th field by compensating a phase of the k th field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected k th field and the (k−1) th field of the interlaced picture signal; calculating a second motion vector between the (k−1) th field and the (k+1) th field of the interlaced picture signal; and determining whether there is motion of the input picture based on the first and second motion vector values, and generating a k th progressive frame based on the result and the k th field. Also, the method may further include: generating an adaptive motion vector based on the first and second motion vectors; generating an adaptive motion compensated field based on the generated adaptive motion vector, the (k−1) th field, and the (k+1) th field; and calculating a correlation between the first and second motion vectors, and if the calculated correlation is larger than the critical value, generating a progressive frame based on the adaptive motion vector. According to another aspect of the present invention, there is provided an adaptive de-interlacing apparatus based on a phase corrected field of an input interlaced picture signal, including: a phase corrector, which generates a phase corrected k th field by compensating a phase of the k th field of the input interlaced picture signal by 1 line frequency; a first motion vector calculator, which calculates a first motion vector between the phase corrected k th field and the (k−1) th field of the interlaced picture signal; a second motion vector calculator which calculates a second motion vector between the (k−1) th field and the (k+1) th field of the interlaced picture signal; and a picture converter, which determines whether there is motion of the input picture based on the first and second motion vector values, and generates a k th progressive frame based on the result and the k th field. According to another aspect of the present invention, there is provided a recording medium storing computer programs for executing an adaptive de-interlacing method based on a phase corrected field of an input interlaced picture signal, the method including: generating a phase corrected k th field by compensating a phase of the k th field of the input interlaced picture signal by 1 line frequency; calculating a first motion vector between the phase corrected k th field and the (k−1) th field of the interlaced picture signal; calculating a second motion vector between the (k−1) th field and the (k+1) th field of the interlaced picture signal; and determining whether there is motion of the input picture based on the first and second motion vector values, and generating a k th progressive frame based on the result and the k th field.
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20040630
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20071023
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20050210
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67870.0
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KOSTAK, VICTOR R
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ADAPTIVE DE-INTERLACING METHOD AND APPARATUS BASED ON PHASE CORRECTED FIELD, AND RECORDING MEDIUM STORING PROGRAMS FOR EXECUTING THE ADAPTIVE DE-INTERLACING METHOD
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UNDISCOUNTED
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ACCEPTED
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10,879,735
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ACCEPTED
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Device for applying a cap on the neck of a bottle or similar container, gripping assembly forming part of this device, and method to be performed by this device
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A device for applying a cap on the neck of a bottle or similar container comprises an applying head movable along an axis and provided with an assembly for gripping the cap having a tubular body with an end mouth which is adapted to receive and hold within it the cap. Inside said tubular body is mounted freely slidable an ejector member. Stop means are provided to limit the upwards displacement of the ejector member with respect to a fixed reference when the applying head moves upwards subsequent to an application of a cap.
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1. A device for applying a cap on the neck of a bottle or similar container, comprising an applying head movable along an axis and provided with an assembly for gripping the cap having a tubular body with an end mouth which is adapted to receive and hold within it the cap, and in which inside said tubular body is mounted an ejector member, slidable along said axis, wherein said ejector member is mounted freely slidable within the tubular body of the gripping assembly and that stop means are provided to limit the upward displacement of said ejector member relative to a fixed reference when the applying head moves upwards after the application of the cap on the bottle. 2. A device as claimed in claim 1, wherein said ejector member is mounted freely slidable within said tubular body of the gripping assembly between two extreme end stop positions. 3. A device as claimed in claim 1, wherein said stop means comprise at least a stop surface that fixed with respect to a fixed reference, and at least an element rigidly connected to the ejector member and positioned outside said tubular body. 4. A device as claimed in claim 1, wherein said element positioned outside the tubular body is rigidly connected to the ejector member by means of transverse pin which engages longitudinal slits obtained in the wall of the tubular body of the gripping assembly. 5. A device as claimed in claim 4, wherein said element is ring shaped, with an stop surface able to co-operate with said fixed stop surface. 6. A device as claimed in claim 1, wherein said ejector member has a cup-shaped cylindrical body. 7. A device as claimed in claim 5, wherein said tubular body has a circumferential series of longitudinal slits, two diametrically opposite slits comprised in said series being engaged by said transverse pin. 8. A device as claimed in claim 7, wherein said longitudinal slits are obtained in an intermediate portion with reduced diameter of the tubular body of the gripping assembly. 9. An assembly for gripping the cap, able to be associated to an applying head comprised in a device for applying a cap on the neck of a bottle or similar container, in which said gripping assembly has a tubular body with an end mouth that is able to receive and hold within it the cap, and in which inside said tubular body is slidably mounted along an axis an ejector member, wherein said ejector member is mounted freely slidable within the tubular body of the gripping assembly and that stop means are provided to limit the upwards displacement of said ejector member with respect to a fixed reference when the applying head moves upwards subsequent to the application of the cap on the bottle. 10. A machine for applying stoppers or caps on the neck of a bottle or similar container, comprising a carrousel structure with a plurality of applying devices as claimed in claim 1. 11. A method for applying a cap on the neck of a bottle or similar container, in which an applying head is provided, slidable along an axis and fitted with an assembly for gripping the cap, said grip assembly having a tubular body with an end mouth that is able to receive and hold within it the cap, and in which within said tubular assembly an ejector member is mounted slidable along said axis, in which the applying head picks up a cap by means of said gripping assembly, and it subsequently lowered over the neck of the bottle to apply the cap thereon, and then rises again in which moreover, during the rising of the head said ejector member ejects the cap from the gripping assembly if the cap has remained therein as a result of its failure to be applied on the neck of the bottle. wherein said ejector member is mounted freely slidable within the tubular body of the gripping assembly and in that during the rise of the head said freely slidable ejector member is prevented from rising beyond a predetermined fixed reference, so that the further rise of the head causes the ejector member to be approached to the gripping mouth with the consequent ejection of a cap that has remained within it after the application of the cap.
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BACKGROUND OF THE INVENTION The present invention relates to devices for applying a stopper or cap on the neck of a bottle or similar container, of the type comprising an applying head movable along an axis and provided with an assembly for gripping the cap having a tubular body with an end mouth for receiving and holding the cap, and wherein is slidably mounted an ejector member inside said tubular body along said axis. A device of the type specified above is disclosed, for instance, in European patent application EP 1 103 513 A1, which refers to a screwing device in which the applying head is provided both with an axial movement, and with a rotary movement for screwing a cap onto the threaded neck of a bottle. In known devices of this kind, an ejector member is provided to eject the cap from the gripping assembly if, for any reason, the operation of applying the cap is not performed and the cap remains caught within the gripping assembly. A high production rate machine for applying caps on bottles typically has a general carrousel configuration, with a plurality of applying heads which operate moving in synchronism along the carrousel together with the supports for the bottles. While each applying head and the corresponding bottle positioned below it move along the carrousel, the applying head previously loaded with a cap moves downwards and rotates, screwing the cap on the neck of the bottle, then returns to a raised position. Obviously, if the screwing operation is not performed, for example because the bottle is missing, or because of a misaligned positioning of the cap in the gripping assembly of the head, the cap remains in the gripping assembly also during the final phase of re-raising of the head, so it must be eliminated before the head, as the rotation of the carrousel continues, reaches the position where a new cap is picked up to perform a new cycle on a new bottle. In prior art devices, the ejector member is constituted by a stem element which is mounted axially slidable through the head and which is controlled in its axial position by a respective actuating transmission. For example, in the case of conventional machines, both the axial motion of the head and the axial motion of the ejector stem are obtained by using cam-following rollers, borne by said elements, which roll on cam tracks during the rotation of the carrousel. The provision of an ejector member according to the prior art described above therefore entails a construction complication and it is a source of drawbacks from the standpoint of the compatibility of the machine with the regulations on cleanliness and health to be enforced in the case of certain types of bottles and containers, in relation to their content. The provision of an ejector member slidably guided through the applying head is not advantageous from this point of view, because the ejector member continually moves between the lower area of the head, which must be kept clean and aseptic, and the upper area, which is kept isolated by the lower part because it includes the various actuation mechanisms of the machine and the related lubrication system. SUMMARY OF THE INVENTION The main object of the present invention therefore is to provide a device of the type set out at the start of the present description which is capable of overcoming the aforementioned drawbacks. An additional object of the invention is to provide a device of the type set out above, in which the ejector member is characterised by an extremely simple, low cost structure. Yet a further object of the invention is to provide a device of the type set out above, in which the ejector member does not require an additional constructive complication of the machine in relation to the need to control its axial position. Lastly, an object of the invention is to reach the above objects whilst assuring the cleanliness of the environment where the cap is applied on the bottle. These and other objects and advantages of the invention are achieved by means of a device having the characteristics set out at the start of the present description and further characterised in that the aforesaid ejector member is mounted freely slidable within the tubular body of the gripping assembly and in that stop means are provided to limit the upwards displacement of said ejector member relative to a fixed reference when the applying head moves upwards after a cap application phase. Thanks to the aforesaid characteristic, the structure of the ejector member can be extremely simplified. Moreover, since the ejector member is mounded freely slidable within the gripping assembly, it is not necessary to provide and system for the positive control of the axial position of the ejector member, with a consequent further simplification relative to prior art machines. With the device according to the invention, if during a rotation of the carrousel the cap borne by the applying head is not applied to a respective bottle, so that the applying head is raised again with the cap still caught within the gripping assembly, the ejector member ejects the cap without any positive command being required on the ejector member. During the re-raising of the head, after the ejector member comes in contact with the aforesaid stop means it is no longer able to follow the head in its rising movement. Therefore, the additional rising of the head causes a relative displacement of the ejector member in the direction of the head gripping mouth, with the consequent ejection of the cap. The aforesaid stop means can be constituted by any fixed stop surface able to come in contact with any part or element rigidly connected to the ejector member. For example, in a preferred embodiment, the ejector member is constituted by a cylindrical body slidably mounted in the tubular body of the gripping assembly and said cylindrical body is rigidly connected to a ring mounted slidably outside the tubular body of the gripping assembly, through a diametrical pin which engages longitudinal slits obtained in the wall of the tubular body of the gripping assembly. The aforesaid ring which is slidably mounted outside the tubular body of the gripping assembly, and which is rigidly connected to the ejector member, comes in contact with the aforesaid stop surface determining the arrest of the ejector member during the head raising phase, with the consequent relative approach of the ejector member to the grip mouth. Naturally, the conformation of the ejector member, the conformation of the stop means, and the conformation of the part connected to the ejector member destined to co-operate with the stop surface can also be wholly different from the example mentioned herein. BRIEF DESCRIPTION OF THE DRAWINGS Additional characteristics and advantages of the present invention shall become readily apparent from the description that follows with reference to the accompanying drawings, provided purely by way of explanatory and non limiting example, in which: FIG. 1 is a schematic elevation view of an applying head according to the present invention, in a first operating phase, FIG. 2 is a view in enlarged scale of a detail of the head of FIG. 1, in a second operating phase, FIG. 3 is a schematic diagram showing the configuration of a machine using the device according to the invention, seen in plan view, FIG. 4 is a partially sectioned schematic view of the gripping assembly comprised in the device according to the invention, and FIG. 5 is an exploded perspective bottom view of the assembly of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION In FIG. 1, the reference number 1 globally designates a screwing head, for screwing plastic caps of the type designated by the reference C on the threaded neck of bottles. The accompanying drawings show only the screwing head and in detail the assembly for gripping the cap C borne by the head 1. Not shown, instead, is the structure of the machine whereon the head 1 is mounted, which can be obtained in any known manner. As mentioned above, machines of this kind typically have a carrousel structure with a plurality of screwing heads which move circumferentially along the carrousel in synchronism with respective supports for the bottles. At each revolution of the carrousel, each screwing head moves axially and rotates to screw a cap on a respective bottle. During each operating cycle, according to the prior art, each screwing head picks up a respective cap from a cap loader, which drops rotating over the neck of a respective bottle to screw the cap and then rises to a top dead centre position where it is again ready to pick up a new cap. FIG. 3 of the accompanying drawings schematically shows a plan view of the circumferential trajectory T travelled by each screwing head 1 in its movement around the central axis A of the carrousel. In the illustrated example, the movement of the carrousel is clockwise, as shown by the arrow F. The reference P designates the area where each screwing head is at its top dead centre and is thus able to pick up a cap which moves circumferentially along a trajectory E, borne, also in accordance with the prior art, by a cap loader disk, which rotates around an axis B parallel to the axis A. The cycle of application of a cap on a bottle starts with the pick up in proximity to P of a new capsule by the screwing head and is performed whilst the latter moves along the circumferential trajectory T. In accordance with the prior art are also obtained the means for actuating the movement of the screwing head 1 along its axis 2 (FIG. 1), as well as the rotation of the screwing head 1 around the axis 2. Such Means can be obtained in any known fashion and in themselves they are outside the scope of the present invention. For this reason, said constructive detail have been omitted from the accompanying drawings, also to make them more readily and easily understandable. The screwing head 1 bears at its lower end a gripping head 3, more clearly visible in FIGS. 2-5. According to a characteristic known in itself, the gripping assembly 3 comprises a body 4 with tubular conformation which defines within it a seat 5 for gripping the cap C. For this purpose, the body 4 has a mouth 6 provided with means able elastically to hold the cap C. In the illustrated example, according to a known technique, said means comprise a plurality of balls 7 and one or more elastic rings 8 which surround them circumferentially. The balls 7 project through openings of the inner surface of the seat 5 in such a way as to be pressed against the lateral wall of the cap C by the elastic rings 8. When the screwing head 1 is lowered on a cap C carried by the loader disk to pick it up, the cap C enters the seat 5 overcoming the action of the elastic rings 8 and is held within said seat by effect of the elastic reaction of the rings 8, which thrust the balls 7 against the lateral wall of the cap C. During the screwing of the cap, the screwing head 1 is lowered along the axis 2 in the direction of the neck of the bottle positioned below it, and it simultaneously rotates to screw the cap on the neck of the bottle. Once the screwing operation is completed, the head 1 is raised again, whilst the cap C, being screwed on the bottle, remains integral with the bottle and thus exits the seat 5 of the gripping assembly 3, overcoming the action of the elastic rings 8. As illustrated above, it may occur that the cap screwing operation is not completed successfully, for instance if the bottle is missing below the screwing head or for any other reason, for example because of a misaligned positioning of the cap within the gripping assembly 3. In this case, it is obviously necessary to eject the cap C that has not been used by the gripping member before the latter must pick up a new cap for a new cycle. For this purpose, inside the tubular body 4 of the gripping member 3 is slidably mounted an ejector member 9 that in the illustrated example has a cup-shaped cylindrical body. In prior art solutions, the ejector member is constituted by a rod sliding through the screwing head 1 which is positively actuated by means of actuation means, for example of the cam type, in order positively to control its position in the axial sense in each phase of the operation of the machine. In the present invention, instead, the ejector member 9 is free and not subject to any command over its position. With reference to the preferred embodiment illustrated herein, to the ejector member 9 is rigidly connected a ring 10 which is slidably mounted outside the tubular body 4, over an intermediate portion with reduced diameter, designated by the reference number 4a in FIG. 5. The external ring 10 is rigidly connected to the internal ejector member 9 by means of a diameter pin 11 which engages a pair of longitudinal slits 12 obtained in the intermediate portion 4a of the tubular body 4 and which are part of a plurality of slits 12, serving a lightening function as well, obtained in said body 4. As FIGS. 1, 2 and 4 clearly show, the ejector member 9 is thus free to slide within the tubular body 4 of the gripping assembly, said movement having two end stop positions defined by the engagement of the transverse pin 11 against the two opposite ends of the pair of longitudinal slits 12 engaged by the pin 11. Again with reference to the drawings, in a normal static condition of the device the ejector member 9 is kept by gravity in its lower end stop position, closer to the end mouth 6 of the gripping assembly 3. When a cap is picked up, the gripping member 3 is lowered onto it, so it penetrates in the seat 5 of the gripping member, making the ejector member 9 move rearwards to the position shown in FIG. 1. The relative position between tubular body 4 and ejector member 9 does not change during the phase in which the cap is screwed onto the bottle. Once the screwing operation is completed, when the screwing head 1 rises again, the upwards displacement of the ejector member 9 is limited by the presence of stop members that come in contact with a circumferential flange 10a of the ring 10 integral with the ejector member 9. Said stop means can be defined for example by a pair of walls 13, 14 (see FIGS. 1-3) situated circumferentially along the trajectory T of the carrousel (FIG. 3) immediately upstream, with reference to the direction of the movement, relative to the area P where a new cap is to be picked up. As illustrated in FIG. 2, after the ring 10 comes in contact with the stop walls 13, 14, the further rise of the screwing head 1 causes a relative upwards displacement of the tubular body 4 with respect to the ejector member 9 or, which is the same, a relative downwards movement of the ejector member 9 with respect to the tubular body 4. The ejector member 9 thus moves in the direction of the mouth 6 of the gripping assembly 3 causing the ejection of the cap C, if said cap has not been screwed onto the bottle and therefore needs to be ejected from the gripping assembly. Naturally, the arrest against the walls 13,14 takes place only if a cap C has remained in the gripping member 3. In the case of correct operation, instead, after the cap has been applied onto the bottle the movable equipment constituted by the ejector member 9 and by the walls 10, 11 connected thereto falls by gravity in its lower end stop position. With reference to the specific embodiment illustrated herein, the transverse pin 1 engages opposite holes 10b of the ring 10 (FIG. 5), a through transverse hole 9a obtained in the bottom wall of the cup-shaped ejector member 9, and is held in position by means of a screw 20 (FIG. 2) which engages a hole obtained starting from the bottom surface of the cup-shaped member 8. In FIG. 5, the balls 7 are not shown, for the sake of simplicity. Obviously, the conformation of the ejector member 9 can be wholly different from the one illustrated by way of example herein, and different can be the conformation and arrangement of the part or of the element positioned outside the tubular body 4 which is rigidly connected to the internal ejector member 9 and which co-operates with the stop means to limit the upwards travel of the ejector member 9 during the rise of the head if a cap has remained in the gripping member 3 after an attempted application onto a bottle. It is readily apparent that, thanks to the characteristics set out above, the structure of the ejector member is extremely simplified, since it is constituted by an element that is freely slidable within the tubular body of the gripping assembly. The machine whereon the device is mounted, moreover, benefits from a considerable simplification, since it need not be provided with any type of command, be it mechanical or electrical, of the axial movement of the ejector member. Lastly, the device is also better than prior art devices from the viewpoint of safety and hygiene, because it has no sliding parts that continually move between the lower area of the machine, usually held in sterile atmosphere, and the upper area of the machine, where the mechanical members with their lubrications are typically housed. Naturally, without altering the principle of the invention, the construction details and the embodiments may vary widely from what is described and illustrated purely by way of example herein, without thereby departing from the scope of the present invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to devices for applying a stopper or cap on the neck of a bottle or similar container, of the type comprising an applying head movable along an axis and provided with an assembly for gripping the cap having a tubular body with an end mouth for receiving and holding the cap, and wherein is slidably mounted an ejector member inside said tubular body along said axis. A device of the type specified above is disclosed, for instance, in European patent application EP 1 103 513 A1, which refers to a screwing device in which the applying head is provided both with an axial movement, and with a rotary movement for screwing a cap onto the threaded neck of a bottle. In known devices of this kind, an ejector member is provided to eject the cap from the gripping assembly if, for any reason, the operation of applying the cap is not performed and the cap remains caught within the gripping assembly. A high production rate machine for applying caps on bottles typically has a general carrousel configuration, with a plurality of applying heads which operate moving in synchronism along the carrousel together with the supports for the bottles. While each applying head and the corresponding bottle positioned below it move along the carrousel, the applying head previously loaded with a cap moves downwards and rotates, screwing the cap on the neck of the bottle, then returns to a raised position. Obviously, if the screwing operation is not performed, for example because the bottle is missing, or because of a misaligned positioning of the cap in the gripping assembly of the head, the cap remains in the gripping assembly also during the final phase of re-raising of the head, so it must be eliminated before the head, as the rotation of the carrousel continues, reaches the position where a new cap is picked up to perform a new cycle on a new bottle. In prior art devices, the ejector member is constituted by a stem element which is mounted axially slidable through the head and which is controlled in its axial position by a respective actuating transmission. For example, in the case of conventional machines, both the axial motion of the head and the axial motion of the ejector stem are obtained by using cam-following rollers, borne by said elements, which roll on cam tracks during the rotation of the carrousel. The provision of an ejector member according to the prior art described above therefore entails a construction complication and it is a source of drawbacks from the standpoint of the compatibility of the machine with the regulations on cleanliness and health to be enforced in the case of certain types of bottles and containers, in relation to their content. The provision of an ejector member slidably guided through the applying head is not advantageous from this point of view, because the ejector member continually moves between the lower area of the head, which must be kept clean and aseptic, and the upper area, which is kept isolated by the lower part because it includes the various actuation mechanisms of the machine and the related lubrication system.
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<SOH> SUMMARY OF THE INVENTION <EOH>The main object of the present invention therefore is to provide a device of the type set out at the start of the present description which is capable of overcoming the aforementioned drawbacks. An additional object of the invention is to provide a device of the type set out above, in which the ejector member is characterised by an extremely simple, low cost structure. Yet a further object of the invention is to provide a device of the type set out above, in which the ejector member does not require an additional constructive complication of the machine in relation to the need to control its axial position. Lastly, an object of the invention is to reach the above objects whilst assuring the cleanliness of the environment where the cap is applied on the bottle. These and other objects and advantages of the invention are achieved by means of a device having the characteristics set out at the start of the present description and further characterised in that the aforesaid ejector member is mounted freely slidable within the tubular body of the gripping assembly and in that stop means are provided to limit the upwards displacement of said ejector member relative to a fixed reference when the applying head moves upwards after a cap application phase. Thanks to the aforesaid characteristic, the structure of the ejector member can be extremely simplified. Moreover, since the ejector member is mounded freely slidable within the gripping assembly, it is not necessary to provide and system for the positive control of the axial position of the ejector member, with a consequent further simplification relative to prior art machines. With the device according to the invention, if during a rotation of the carrousel the cap borne by the applying head is not applied to a respective bottle, so that the applying head is raised again with the cap still caught within the gripping assembly, the ejector member ejects the cap without any positive command being required on the ejector member. During the re-raising of the head, after the ejector member comes in contact with the aforesaid stop means it is no longer able to follow the head in its rising movement. Therefore, the additional rising of the head causes a relative displacement of the ejector member in the direction of the head gripping mouth, with the consequent ejection of the cap. The aforesaid stop means can be constituted by any fixed stop surface able to come in contact with any part or element rigidly connected to the ejector member. For example, in a preferred embodiment, the ejector member is constituted by a cylindrical body slidably mounted in the tubular body of the gripping assembly and said cylindrical body is rigidly connected to a ring mounted slidably outside the tubular body of the gripping assembly, through a diametrical pin which engages longitudinal slits obtained in the wall of the tubular body of the gripping assembly. The aforesaid ring which is slidably mounted outside the tubular body of the gripping assembly, and which is rigidly connected to the ejector member, comes in contact with the aforesaid stop surface determining the arrest of the ejector member during the head raising phase, with the consequent relative approach of the ejector member to the grip mouth. Naturally, the conformation of the ejector member, the conformation of the stop means, and the conformation of the part connected to the ejector member destined to co-operate with the stop surface can also be wholly different from the example mentioned herein.
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20040630
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20080527
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20050825
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66621.0
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PARADISO, JOHN ROGER
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DEVICE FOR APPLYING A CAP ON THE NECK OF A BOTTLE OR SIMILAR CONTAINER, GRIPPING ASSEMBLY FORMING PART OF THIS DEVICE, AND METHOD TO BE PERFORMED BY THIS DEVICE
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UNDISCOUNTED
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ACCEPTED
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10,879,743
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ACCEPTED
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Vehicular hood structure and vehicle body front portion structure
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In order to archive to improve impact absorbing efficiency and lower production costs, a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, and a front-ear direction inner member that is disposed along the vehicle body front-rear direction between the front end portion configuration member and the rear end portion configuration member and which bridges the front end portion configuration member and the rear end portion configuration member is provided.
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1. A vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, and a front-ear direction inner member that is disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member and which bridges the front end portion inner member and the rear end portion inner member. 2. The vehicular hood structure of claim 1, wherein respective couplings between the hood outer member, the front end portion inner member, the rear end portion inner member and the front-rear direction inner member are couplings in a separation direction and a shearing direction. 3. The vehicular hood structure of claim 1, wherein a surface of the front-rear direction inner member opposing the outer member is smoothly formed, has a shape along an undersurface of the outer member and extends as far as front and rear ends of the outer member. 4. The vehicular hood structure of claim 1, wherein a front end portion of the front-rear direction inner member extends above a hood lock or a hood stopper. 5. The vehicular hood structure of claim 3, wherein a front end portion of the front-rear direction inner member is nipped and joined between the outer member and the front end portion inner member, and a rear end portion of the front-rear direction inner member is nipped and joined between the outer member and the rear end portion inner member. 6. The vehicular hood structure of claim 3, wherein side wall portions of a front end portion of the front-rear direction inner member are joined to one of the front end portion inner member or a lock reinforcement. 7. The vehicular hood structure of claim 3, wherein lower portions of left and right side walls of the front-ear direction inner member are joined to correspond to at least one of end portions of a hood lock striker. 8. The vehicular hood structure of claim 6, wherein a stepped portion including a fold line in the vehicle body front-rear direction is formed in the side wall portion of the front-rear direction inner member. 9. The vehicular hood structure of claim 1, wherein front and rear end portions of the front-rear direction inner members plurally disposed at predetermined intervals in the vehicle width direction are nipped and joined between the outer member and the front end portion inner member and the outer member and the rear end portion inner member, and between adjacent joint portions, gaps are formed between the outer member and the front end portion inner member and the outer member and the rear end portion inner member. 10. The vehicular hood structure of claim 1, wherein an impact absorbing bracket is provided between, at least one of a lower surface of the front-ear direction inner member and an upper surface of the front end portion inner member and the lower surface of the front-rear direction inner member and an upper surface of the rear end portion inner member. 11. The vehicular hood structure of claim 1, wherein a recessed portion formed in a front portion of the rear end portion inner member is partially or completely closed off by the front-ear direction inner member. 12. A vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes at least one open portion formed in the inner member, with a rear end edge portion of the open portion at a hood rear portion being set on an arcuate line where a vehicle width-direction center portion thereof is convex towards the vehicle body front. 13. A vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, a plurality of front-rear direction inner members that are disposed along the vehicle body front-ear direction between the front end portion inner member and the rear end portion inner member and which bridge the front end portion inner member and the rear end portion inner member, at least one open portion formed in the inner member, and at least one reinforcement member disposed along the vehicle body front-ear direction at a rear end edge portion of the open portion at a hood rear portion at interval with the plurality of front-ear direction inner members between the plurality of front-ear direction inner members. 14. A vehicle body front portion structure comprising: a vehicular hood comprising a hood outer member configuring a vehicle body outer side surface and a hood inner member that is disposed at the inner side of the outer member and includes at least one open portion; and a front bumper, wherein at a side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from a point end portion of the front bumper to a front end edge portion of the open portion is substantially constant. 15. The vehicle body front portion structure of claim 14, wherein the length from the point end portion of the front bumper to the front end edge portion of the open portion is a length of an arcuate curved line along the outer contour of the vehicle body. 16. A vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, front-rear direction inner side members that are disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member at sides portions and which bridge the front end portion inner member and the rear end portion inner member, and at least one front-rear direction inner center member that is disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member and which bridges the front end portion inner member and the rear end portion inner member. 17. The vehicular hood structure of claim 8, wherein at a coupling portion of the front-rear direction inner member, the front-rear direction inner member is coupled via another member. 18. The vehicular hood structure of claim 13, wherein the at least one reinforcement member is formed integrally with the rear end portion inner member.
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CROSS-REFERENCE TO RELATED APPLICATION This application claims priority under 35 USC 119 from Japanese Patent Applications Nos. 2003-189499, 2003-191695 and 2003-193382 the disclosures of which are incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular hood structure and a vehicle body front portion structure, and in particular to a vehicular hood structure and a vehicle body front portion structure that protects a collision body at the time of a collision in a vehicle such as an automobile. 2. Description of the Related Art Conventionally, with respect to a vehicular hood structure that protects a collision body at the time of a collision in a vehicle such as an automobile, a configuration is known where one inner member formed by press molding is integrated with an outer member by hemming, and a lock reinforcement is attached between the outer member and the inner member at a hood lock striker support portion (e.g., see Japanese Patent Application Laid-Open Publication (JP-A) No.11-321714). A configuration is also known where the thickness of an aluminium alloy serving as the outer member is 0.5 mm to 2.0 mm and a reinforcement member that lines the outer member is about 3 mm to 15 mm (e.g., see JP-A No.2001-191962). A configuration including an annularly-formed outer frame and an inner skeletal member that bridges the outer frame along the vehicle body front-rear direction is also known (e.g., see JP-A No. 6-72355). A configuration where the lock reinforcement includes walls extending in the vehicle body front-ear direction at the left and right sides of a hood lock striker is also known (e.g., see JP-A No.6-312670). A configuration where the inner member comprises an annular frame skeleton and an inner skeleton that forms a closed cross section by being coupled to the frame skeleton inward of the frame skeleton, and where the longitudinal walls of the cross section are substantially vertical surfaces, is also known (e.g., see JP-A No. 5-278637). A configuration where the side end portions of the hood curve back inward and end portions hang down is also known (e.g., see JP-A No. 2001-301541). However, with respect to the technology of JP-A No. 11-321714, the production costs are high because the inner member is a large pressed part. Also, because the closed cross section, which is formed by the outer member and the inner member and extends in the vehicle body front-rear direction and the vehicle width direction, and the lock reinforcement are disposed, deformation of the hood for absorbing impact when a collision body collides with the hood is obstructed, a reaction force in the vehicle body front-rear direction is generated, and the impact absorbing efficiency is lowered. With respect to the vehicular hood structure (FIGS. 4 and 8) of JP-A No. 11-321714, a configuration is known where, in an automobile hood (also called a bonnet) where an inner panel (also called an inner frame) is integrated with an outer panel, a reinforcement panel attached to the inner panel is folded in the shape of Mt. Fuji by a front slanted panel, a top panel and a rear slanted panel, with a slit being disposed in the top panel so that the top panel is divided into a front top panel and a rear top panel, and edge reinforcement members that reinforce the edges of the front top panel and the rear top panel are attached to the front top panel and the rear top panel, whereby, when a collision body hits the vicinity of the attachment portion of the striker from the outer panel side, the outer panel is deformed, the outer panel is received by the edge reinforcement members respectively disposed at the front top panel and the rear top panel, the energy of the collision body is initially absorbed, and then the front slanted panel and the rear slanted panel secondarily absorb the energy of the flexing obstacle. However, in JP-A No.11-321714, the reinforcement panel is disposed in the front portion region of the hood. As a result, when a collision body collides with the rear portion region of the hood, the reinforcement panel has no energy absorbing effect with respect to the collision body. Moreover, in the vehicle body front portion structure (FIGS. 5, 6 and 7) of JP-A No. 11-321714, a configuration is known where, with respect to an automobile hood where the inner panel is integrated with the outer panel, the inner panel is one molded part that is press-molded, and an open portion is formed in the inner panel in order to reduce weight and improve hood rigidity. However, in JP-A No. 11-321714, the closed cross-sectional structure is formed by adhering the edge portion of the open portion of the inner panel to the undersurface of the outer panel, and although hood rigidity is improved, the collision load on the collision body is not uniform, regardless of differences in the vehicle width direction of the collision positions, when a collision body collides with the front portion region of the hood. SUMMARY OF THE INVENTION In consideration of the above-described facts, it is an object of the present invention to provide a vehicular hood structure with which it is possible to improve impact absorbing efficiency and lower production costs. It is another object of the invention to provide a vehicular hood structure that can improve energy absorbing efficiency with respect to a collision body when a collision body collides with the rear portion region of a hood. It is yet another object of the invention to provide a vehicle body front portion structure that can make uniform a collision load on a collision body, regardless of differences in the vehicle width direction of collision positions, when a collision body collides with the front portion region of a hood. A first aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, and a front-rear direction inner member that is disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member and which bridges the front end portion inner member and the rear end portion inner member. Thus, because the inner member of the hood is divided into the front end portion inner member, the rear end portion inner member and the front-ear direction inner member, the inner member can be divided into plural long parts. As a result, progressive molding becomes possible and production yield increases. As a result, material costs, mold costs and processing costs of the hood can be reduced, and it becomes possible to reduce production costs. Also, because the front-rear direction inner member is disposed along the vehicle body front-ear direction between the front end portion inner member and the rear end portion inner member, when a collision body collides with the hood, deformation of the hood for absorbing the impact is smoothly carried out and a reaction force in the vehicle body front-rear direction is not generated. As a result, the impact absorbing efficiency can be improved A second aspect of the invention provides the vehicular hood structure of the first aspect, wherein respective couplings between the hood outer member, the front end portion inner member, the rear end portion inner member and the front-rear direction inner member are couplings in a separation (peeling) direction and a shearing direction. Thus, in addition to the content of the first aspect, in both the separation direction and the shearing direction, the strength of the respective couplings between the hood outer member, the front end portion inner member, the rear end portion inner member and the front-rear direction inner member is improved, whereby sufficient joint strengths can be obtained even in joints resulting from adhesion. A third aspect of the invention provides the vehicular hood structure of the first aspect, wherein a surface of the front-rear direction inner member opposing the outer member is smoothly formed, has a shape along (according to) an undersurface of the outer member and extends as far as front and rear ends of the outer member. Thus, in addition to the content of the first aspect, in the vicinity of the front and rear end portions of the hood, by making flatly smooth the cross section of the surface of the front-ear direction inner member opposing the outer member, when a collision body collides with the hood, the possibility to generate an unnecessary deceleration load in the front-rear direction with respect to the collision body can be reduced. A fourth aspect of the invention provides the vehicular hood structure of the first aspect, wherein a front end portion of the front-ear direction inner member extends above a hood lock or a hood stopper. Thus, in addition to the content of the first aspect, because the front-rear direction inner member that generates an excellent collision acceleration is disposed above the hood lock or the hood stopper, an excellent collision acceleration can be generated even at a position above the hood lock or the hood stopper, where control of the collision load has conventionally been difficult. A fifth aspect of the invention provides the vehicular hood structure of the third aspect, wherein a front end portion of the front-rear direction inner member is nipped and joined between the outer member and the front end portion inner member, and a rear end portion of the front-rear direction inner member is nipped and joined between the outer member and the rear end portion inner member. Thus, in addition to the content of the third aspect, because each front-rear direction inner member disposed between the front end portion inner member and the rear end portion inner member has a dual supported beam structure, the timing of the load generation can be quickened. A sixth aspect of the invention provides the vehicular hood structure of the third aspect, wherein side wall portions of a front end portion of the front-rear direction inner member are joined to one of the front end portion inner member or a lock reinforcement. Thus, in addition to the content of the third aspect, because the front-rear direction inner member has a dual supported beam structure, the timing of the load generation can be quickened. A seventh aspect of the invention provides the vehicular hood structure of the third aspect, wherein lower portions of left and right side walls of the front-ear direction inner member are joined to correspond to at least one of end portions of a hood lock striker. Thus, in addition to the content of the third aspect, when a collision body collides with the hood directly above the hood lock striker, the cross section of the inner member expands in the vehicle width direction and is deformed. As a result, it becomes possible to control the deformation mode of the inner member using the load where both end portions of the hood lock striker are deformed so that they relatively move away from each other in the vehicle width direction. An eighth aspect of the invention provides the vehicular hood structure of either of the sixth or seventh aspects, wherein a stepped portion including a fold line in the vehicle body front-rear direction is formed in the side wall portion of the front-rear direction inner member. Thus, in addition to the content of either of the sixth or seventh aspects, the stepped portion including the fold line is disposed, whereby rapid change of geometrical moment of inertia (second moment of area) can be alleviated. A ninth aspect of the invention provides the vehicular hood structure of the first aspect, wherein front and rear end portions of the front-rear direction inner members plurally disposed at predetermined intervals in the vehicle width direction are nipped and joined between the outer member and the front end portion inner member and the outer member and the rear end portion inner member, and between adjacent joint portions, gaps are formed between the outer member and the front end portion inner member and the outer member and the rear end portion inner member. Thus, in addition to the content of the first aspect, control is effected, due to the flatly smooth surfaces of the front-rear direction inner members, so that an unnecessary collision acceleration is not generated at the portions where the front-rear direction inner members are present. Further, due to that gaps are formed between the outer member and the front end portion inner member and the outer member and the rear end portion inner member, between adjacent joint portions, the generation of an unnecessary acceleration for which there is the possibility for the front and rear end portions of the front end portion inner member and the rear end portion inner member to be joined to the inner surface of the outer member can be prevented. A tenth aspect of the invention provides the vehicular hood structure of either of the first or ninth aspect, wherein an impact absorbing bracket is provided (intervened) between, at least one of a lower surface of the front-rear direction inner member and an upper surface of the front end portion inner member and the lower surface of the front-rear direction inner member and an upper surface of the rear end portion inner member. Thus, in addition to the content of either of the first or ninth aspect, geometrical moment of inertia (second moment of area) of the front-rear direction inner member is determined by the rigidity required in the hood center region. For this reason, there is little freedom for the cross-sectional height of the front-rear direction inner member in the vicinity of the front and rear end portions, but by intervening the impact absorbing bracket, it becomes possible to generate a desired load (reaction force). An eleventh aspect of the invention provides the vehicular hood structure of the first aspect, wherein a recessed portion formed in a front portion of the rear end portion inner member is partially or completely closed off by the front-rear direction inner member. Thus, in addition to the content of the first aspect, an elastic deformation mode resulting from the recess can be eliminated, and the generation of a reaction force can be promptly launched A twelfth aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes at least one open portion formed in the inner member, with a rear end edge portion of the open portion at a hood rear portion being set on an arcuate line where a vehicle width-direction center portion thereof is convex towards the vehicle body front. Thus, the rear end edge portion at the hood rear portion of the at least one open portion formed in the inner member is set on an arcuate line where a vehicle width-direction center portion thereof is convex towards the vehicle body front. Thus, when a collision body collides with the vehicle width-direction center portion of the rear portion region of the hood, the rear end edge portion of the open portion formed in the inner member approaches lines joining the impact position of the collision body on the hood with both vehicle width-direction end portions of the hood rear end. Thus, immediately after the collision, the rear portion of the hood including the inner member can be made to sink towards the vehicle body bottom together with the collision body. For this reason, when a collision body collides with the rear portion region of the hood, an unnecessary forward G can be reduced, and the energy absorbing effect with respect to the collision body can be improved. A thirteenth aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, a plurality of front-rear direction inner members that are disposed along the vehicle body front-ear direction between the front end portion inner member and the rear end portion inner member and which bridge the front end portion inner member and the rear end portion inner member, at least one open portion formed in the inner member, and at least one reinforcement member disposed along the vehicle body front-ear direction at a rear end edge portion of the open portion at a hood rear portion at interval with the plurality of front-ear direction inner members between the plurality of front-ear direction inner members. Thus, because at least one reinforcement member (preferably, reinforcement members) is disposed along the vehicle body front-ear direction at the rear end edge portion of the open portion at the hood rear portion at intervals with the left and right front-ear direction inner members, when a collision body collides with the hood, the generated load of the rear portion region of the hood can be increased virtually without increasing the generated load at the front portion region of the hood. As a result, when a collision body collides with the rear portion region of the hood, the energy absorbing effect with respect to the collision body can be improved. A fourteenth aspect of the invention provides a vehicle body front portion structure comprising: a vehicular hood comprising a hood outer member configuring a vehicle body outer side surface and a hood inner member that is disposed at the inner side of the outer member and includes at least one open portion; and a front bumper, wherein at a side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from a terminal end site of the front bumper to a front end edge portion of the open portion is substantially constant. Thus, at the side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from the terminal end site of the front bumper to the front end edge portion of the open portion of the inner member that is disposed at the inner side of the outer member of the vehicular hood and includes at least one open portion is substantially constant. Thus, even when a vertically long collision body hits any position in the vehicle width direction of the front bumper, the length between the position on the hood upper surface at which the uppermost portion of the collision body hits and the front end edge portion of the open portion can be made substantially uniform. As a result, when a collision body collides with the front portion region of the hood, the collision load on the collision body can be made uniform regardless of differences in the vehicle width direction of the collision position. A fifteenth aspect of the invention provides the vehicle body front portion structure of the fourteenth aspect, wherein the length from the terminal end site of the front bumper to the front end edge portion of the open portion is a line length of an arcuate curved line along the outer contour of the vehicle body. Thus, at the side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from the terminal end site of the front bumper to the front end edge portion of the open portion of the inner member that is disposed at the inner side of the outer member of the vehicular hood and includes at least one open portion is a line length of an arcuate curved line along the outer contour of the vehicle body and is substantially constant. Thus, even when a vertically long collision body hits a position in the vehicle width direction of the front bumper, the length between the position on the hood upper surface at which the uppermost portion of the collision body hits and the front end edge portion of the open portion can be made substantially uniform. As a result, when a collision body collides with the front portion region of the hood, the collision load on the collision body can be made uniform regardless of differences in the vehicle width direction of the collision position. A sixteenth aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, front-rear direction inner side members that are disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member at sides portions and which bridge the front end portion inner member and the rear end portion inner member, and at least one front-rear direction inner center member that is disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member and which bridges the front end portion inner member and the rear end portion inner member. A seventeenth aspect of the invention provides the vehicular hood structure of the eighth aspect, wherein at a coupling portion of the front-rear direction inner member, the front-rear direction inner member is coupled via another member. An eighteenth aspect of the invention provides the vehicular hood structure of the thirteenth aspect, wherein the at least one reinforcement member is formed integrally with the rear end portion inner member. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view, seen from below a vehicle body, showing a vehicular hood structure pertaining to a first embodiment of the invention; FIG. 2 is an exploded plan view, seen from below the vehicle body, showing an inner panel of the vehicular hood structure pertaining to the first embodiment of the invention; FIG. 3 is an enlarged cross-sectional view along line 3-3 of FIG. 1; FIG. 4 is an enlarged cross-sectional view along line 4-4 of FIG. 1; FIG. 5 is an enlarged cross-sectional view along line 5-5 of FIG. 1; FIG. 6 is an enlarged cross-sectional view along line 6-6 of FIG. 1; FIG. 7 is an enlarged cross-sectional view along line 7-7 of FIG. 1; FIG. 8 is a plan view showing a vehicular hood structure pertaining to a second embodiment of the invention; FIG. 9 is an enlarged cross-sectional view along line 9-9 of FIG. 8; FIG. 10 is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center front end portion of the vehicular hood structure pertaining to the second embodiment of the invention; FIG. 11 is an enlarged cross-sectional view along line 11-11 of FIG. 8; FIG. 12 is an enlarged cross-sectional view along line 12-12 of FIG. 8; FIG. 13 is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center rear end portion of the vehicular hood structure pertaining to the second embodiment of the invention; FIG. 14 is an enlarged cross-sectional view along line 14-14 of FIG. 8; FIG. 15 is an enlarged cross-sectional view along line 15-15 of FIG. 13; FIG. 16 is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center front end portion of a vehicular hood structure pertaining to a modified example of the second embodiment of the invention; FIG. 17 is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center front end portion of a vehicular hood structure pertaining to a modified example of the second embodiment of the invention; FIG. 18A is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center front end portion of a vehicular hood structure pertaining to a modified example of the second embodiment of the invention, and FIG. 18B is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center front end portion of a vehicular hood structure pertaining to a modified example of the second embodiment of the invention; FIG. 19A is a cross-sectional view along line 19-19 of FIG. 18A, and FIG. 19B is a cross-sectional view along line 19-19 of FIG. 18B; FIG. 20 is a cross-sectional view along line 20-20 of FIGS. 19A and 19B; FIG. 21 is a cross-sectional view showing a deformed state of FIGS. 19A and 19B; FIG. 22 is a cross-sectional view corresponding to FIG. 12 of the vehicular hood structure pertaining to the modified example of the second embodiment of the invention; FIG. 23 is a perspective view, seen from diagonally above the vehicle body front, showing a vehicle width-direction center rear end portion of a vehicular hood structure pertaining to a modified example of the second embodiment of the invention; FIG. 24 is a perspective view showing, seen from diagonally above the vehicle body front, a vehicle width-direction center front end portion of a vehicular hood structure pertaining to a modified example of the second embodiment of the invention; FIG. 25 is an enlarged cross-sectional view along line 25-25 of FIG. 24; FIG. 26 is a schematic plan view, seen from below the vehicle body, showing a vehicular hood structure pertaining to a third embodiment of the invention; FIG. 27 is a schematic plan view, seen from below the vehicle body, showing a vehicular hood structure pertaining to a fourth embodiment of the invention; FIG. 28 is an enlarged cross-sectional view along line 5-5 of FIG. 27; FIG. 29 is an enlarged cross-sectional view along line 6-6 of FIG. 27; FIG. 30 is a schematic plan view, seen from below the vehicle body, showing a vehicular hood structure pertaining to a modified example of the fourth embodiment of the invention; and FIG. 31 is an enlarged cross-sectional view along line 3-3 of FIG. 1 showing a vehicle body front portion structure pertaining to a fifth embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION A first embodiment of a vehicular hood structure of the invention will be described in accordance with FIGS. 1 to 7. In the drawings, the IN arrow represents a vehicle width inner side direction, the UP arrow represents a vehicle body up direction, and the FR arrow represents a vehicle body front direction. As shown in FIG. 3, in the present embodiment, an automobile hood 10 is configured by an outer panel 12, which serves as an outer member configuring a vehicle body outer side surface of the hood 10, and an inner panel 14, which is disposed at the inner side of the outer panel 12 and configures an engine room side portion. As shown in FIG. 2, the inner panel 14 of the hood 10 is configured by an inner front 16 that configures a front end portion of the inner panel 14, an inner rear 18 that configures a rear end portion of the inner panel 14, inner sides 20 serving as front-rear direction inner members configuring both vehicle width-direction end portions of the inner panel 14, and three inner centers 22 that are disposed between the left and right inner sides 20 in the vehicle front-rear direction and serve as front-rear direction inner members that bridge the inner front 16 and the inner rear 18. As shown in FIG. 3, rear end portions 22A of the three inner centers 22 are joined to an upper surface of a front flange 18A of the inner rear 18, and front end portions 22B of the three inner centers 22 are joined to an upper surface of a rear flange 16A of the inner front 16. An extension portion 22C is formed at the inner center 22 disposed in the vehicle width-direction center and extends from the front end portion 22B downward towards the vehicle body front side. A front end edge portion 22D of the extension portion 22C is joined to a front surface of a front flange 16B of the inner front 16. Thus, the inner centers 22 and the inner front 16 are joined from a substantial vehicle body vertical direction at the portions where the front end portions 22B and the rear flange 16A are joined, and are also joined from a substantial vehicle body vertical direction at the portion where the front end edge portion 22D and the front flange 16B are joined. As a result, when a load in a separation direction acts on the portions where the front end portions 22B and the rear end flange 16A are joined, a load in a shearing direction acts on the portion where the front end edge portion 22D and the front flange 16B are joined. As shown in FIG. 1, four open portions 30 that extend in the vehicle body front-rear direction are formed in the inner panel 14 by the linear left right inner sides 20 and the three inner centers 22 disposed in parallel along the vehicle body front-rear direction. As shown in FIG. 4, side wall portions 16C of the inner front 16 are joined to vehicle width-direction inner side surfaces of side wall portions 20A of the inner sides 20 at the portions where the inner front 16 and the inner sides 20 are joined, and upper wall portions 16D of the inner fronts 16 are joined to lower surfaces of upper wall portions 20B of the inner sides 20. Thus, the inner sides 20 and the inner front 16 are joined from a substantial vehicle-width direction at the portions where the side wall portions 20A and the side wall portions 16C are joined, and are also joined from a substantial vehicle-width direction at the portions where the upper wall portions 20B and the upper wall portions 16D are joined. As a result, when a load in the separation direction acts on the portions where the side wall portions 20A and the side wall portions 16C are joined, a load in the shearing direction acts on the portions where the upper wall portions 20B and the upper wall portions 16D are joined. Also, side wall portions 12A of the outer panel 12 are joined to vehicle width-direction outer side surfaces of the side wall portions 20A of the inner sides 20. As shown in FIG. 5, side wall portions 18B of the inner rear 18 are joined to vehicle width-direction inner side surfaces of the side wall portions 20A of the inner sides 20 at the portions where the inner rear 18 and the inner sides 20 are joined, and upper wall portions 18C of the inner rear 18 are joined to the lower surfaces of the upper wall portions 20B of the inner sides 20 at the portions where the inner rear 18 and the inner sides 20 are joined. Thus, the inner sides 20 and the inner rear 18 are joined from a substantial vehicle-width direction at the portions where the side wall portions 20A and the side wall portions 18B are joined, and are also joined from a substantial vehicle-width direction at the portions where the upper wall portions 20B and the upper wall portions 18C are joined. As a result, when a load in the separation direction acts on the portions where the side wall portions 20A and the side wall portions 18B are joined, a load in the shearing direction acts on the portions where the upper wall portions 20B and the upper wall portions 18C are joined. As shown in FIG. 6, flanges 16E are formed towards the vehicle width-direction outer sides at the lower end portions of the side wall portions 16C of the inner front 16, and a positioning-use convex portion 16F is formed at the bases of the flanges 16E. It should be noted that reference letter S in FIG. 6 represents a collision body. As shown in FIG. 7, a recess 32 for passing a washer hose 31 is formed in the front flange 18A serving as the front portion of the inner rear 18. The recess 32 is partially (the state shown in FIG. 7) or completely (not shown) closed off by the rear end portions 22A of the inner centers 22. Thus, when a collision body collides with a site above the recess 32 in the hood 10, an elastic deformation mode resulting from the recess 32 can be eliminated by the rear end portions 22A of the inner centers 22, whereby the generation of a reaction force can be promptly launched. This is also efficient in terms of the production process in comparison to a structure where a hole is formed in the inner rear 18 and the washer hose 31 is passed through this hole. Next, the operation of the present embodiment will be described. In the present embodiment, the inner panel 14 of the hood 10 has a divided structure configured by the inner front 16, the inner rear 18, the inner sides 20 and the inner centers 22. Thus, the inner panel 14 can be divided into plural long parts. As a result, progressive molding becomes possible and production yield increases. For this reason, material costs, mold costs and processing costs can be reduced, and it becomes possible to reduce production costs. Also, because the inner panel 14 can be transported and stored in a state where the inner panel 14 is divided, transport and storage of the inner panel 14 become easy. Also, in the present embodiment, as shown in FIG. 3, the inner centers 22 and the inner front 16 are joined from a substantial vehicle body vertical direction at the portions where the front end portions 22B and the rear flange 16A are joined, and are also joined from a substantial vehicle body front-rear direction at the portion where the front end edge portion 22D and the front flange 16B are joined. Also, as shown in FIG. 4, the inner sides 20 and the inner front 16 are joined from a substantial vehicle width-direction at the portions where the side wall portions 20A and the side wall portions 16C are joined, and are also joined from a substantial vehicle body vertical direction at the portions where the upper wall portions 20B and the upper wall portions 16D are joined. Moreover, as shown in FIG. 5, the inner sides 20 and the inner rear 18 are joined from a substantial vehicle width-direction at the portions where the side wall portions 20A and the side wall portions 18B are joined, and are also joined from a substantial vehicle body vertical direction at the portions where the upper wall portions 20B and the upper wall portions 18C are joined. As a result, the respective coupling strengths of the divided inner front 16, the inner rear 18, the inner sides 20 and the inner centers 22 are improved with respect to both the separation direction and the shearing direction. For this reason, a sufficient bonding strength is obtained even at joints resulting from adhesion, and the torsional rigidity of the inner panel 14 can be sufficiently secured. Also, in the present embodiment, as shown in FIG. 1, the inner sides 20 and the inner centers 22 have a dual beam structure disposed along the vehicle body front-rear direction between the inner front 16 and the inner rear 18. As a result, when a collision body collides with the hood 10, deformation of the hood 10 for absorbing the impact is smoothly carried out and a reaction force in the vehicle body front-rear direction is not generated, whereby the impact absorbing efficiency can be improved. Also, the timing of the load generation when a collision body has collided with the hood 10 can be quickened. Next, a second embodiment of the vehicular hood structure of the invention will be described in accordance with FIGS. 8 to 15. It should be noted that identical reference numerals will be given to members that are the same as those of the first embodiment, and that description of those members will be omitted. As shown in FIG. 8, in the present embodiment, one inner center 22 is disposed in the vehicle width-direction center portion of the hood. As shown in FIG. 9, a front end portion 22E of the inner center 22 of the present embodiment extends towards the vehicle body front from the rear flange 16A of the inner front 16, and extends as far as above a hood lock reinforcement 42 disposed above a hood lock or a hood stopper. Also, an upper surface 22F of the inner center 22 opposing the outer panel 12 has a shape that is flatly smooth and is along an undersurface 12B of the outer panel 12, and the upper surface 22F of the inner center 22 is joined by adhesion or welding to the undersurface 12B of the outer panel 12. Reference numeral 41 in FIG. 9 represents a hood lock striker. As shown in FIG. 10, the cross-sectional shape of the inner center 22 seen from the vehicle body front-rear direction is a hat shape where the open portion is oriented towards the vehicle body bottom, and left and right flanges 22G formed at the open end portion are joined to the rear flange 16A of the inner front 16. As shown in FIG. 11, a gap 44 is formed between the outer panel 12 and the rear flange 16A of the inner front 16 at a site where the inner center 22 of the hood 10 is not present. As shown in FIG. 12, the rear end portion 22A of the inner center 22 extends towards the vehicle body rear from the front flange 18A of the inner rear 18, and the upper surface 22F of the inner center 22 is joined by adhesion or welding to the undersurface 12B of the outer panel 12. As shown in FIG. 13, the left and right flanges 22G of the inner center 22 are joined to the front flange 18A of the inner rear 18. As shown in FIG. 14, a gap 46 is formed between the outer panel 12 and the front flange 18A of the inner rear 18 at a site where the inner center 22 of the hood 10 is not present. Next, the operation of the present embodiment will be described. In the present embodiment, in addition to the operation and effects of the first embodiment, the front end portion 22E of the inner center 22 extends towards the vehicle body front from the rear flange 16A of the inner front 16, and the rear end portion 22A of the inner center 22 extends towards the vehicle body rear from the front flange 18A of the inner rear 18. Also, the upper surface 22F of the inner center 22 opposing the outer panel 12 has a shape that is flatly smooth and is along the undersurface 12B of the outer panel 12, and the upper surface 22F of the inner center 22 is joined by adhesion or welding to the undersurface 12B of the outer panel 12. As a result, the cross section of the upper surface 22F of the inner center 22 can be made flatly smooth in the vicinity of the front end portion and in the vicinity of the rear end portion of the hood 10, and the potential to generate an unnecessary deceleration load in the front-ear direction with respect to a collision body at the time of a collision with a collision body can be reduced. Also, in the present embodiment, the front end portion 22E of the inner center 22 extends as far as above the hood lock reinforcement 42. Namely, the inner center 22, which generates an excellent collision acceleration, is disposed above the hood lock reinforcement 42. For this reason, an excellent collision acceleration can be generated even at a position above the hood lock reinforcement 42, at which control of the collision load has conventionally been difficult. Moreover, the rigidity of the hood 10 in a case where the site directly above the hood lock reinforcement 42 is pressed can be improved. Also, in the present embodiment, as shown in FIG. 11, the gap 44 is formed between the outer panel 12 and the rear flange 16A of the inner front 16 at a site where the inner center 22 is not present at the hood 10, and as shown in FIG. 14, the gap 46 is formed between the outer panel 12 and the front flange 18A of the inner rear 18 at a site where the inner center 22 is not present at the hood 10. As a result, when a collision body collides with a site where the inner center 22 of the hood 10 is not present, generation of an unnecessary collision acceleration can be prevented, and a secondary collision acceleration can be reduced. Moreover, it becomes easy for a rust-preventing coating to enter between the outer panel 12 and the inner front 16 or the inner rear 18, so that the rust-preventing performance is improved. Also, in the embodiment and a modified embodiment thereof as shown in FIG. 15 in which plural inner centers 22 are provided, even when a collision body S collides with the hood 10 between adjacent inner centers 22 at the site of the outer panel 12 opposing the inner rear 18, deformation of the outer panel 12 can be suppressed by the adjacent inner centers 22. As a result, the outer panel 12 can be prevented from abutting against the inner rear 18 to prevent an unnecessary acceleration from being generated. As shown in FIG. 16, both side wall portions 22H may extend downward at the front end portion 22E of the inner center 22, and the flanges 22G at the lower ends of both side wall portions may be joined by adhesion or welding to the inner panel 14 or the hood lock reinforcement 42. In this case, the inner panel 14 or the hood lock reinforcement 42 can be supported at both side wall portions 22H of the inner center 22. As a result, it becomes difficult for local deformation to occur at a collision portion when a collision body collides with the front portion of the hood 10, so that unnecessary acceleration in the front-ear direction can be reduced. Also, the rigidity in a case where the site of the hood 10 directly above the hood lock reinforcement 42 is pressed can be further improved. As shown in FIG. 17, fold lines 22J along the vehicle body front-ear direction may be formed in both side wall portions 22H at the front end portion 22E of the inner center 22, and joint portions 22K formed at the lower ends of both side wall portions 22H may be joined by adhesion or welding to the inner panel 14 or the hood lock reinforcement 42. In this case, the fold lines 22J can alleviate a second moment of area of the inner center 22 generated when a collision body collides with the hood 10 from suddenly changing at the sites where both side wall portions 22H of the inner center 22 are joined to the inner panel 14 or the hood lock reinforcement 42 and the sites rearward of these sites. As a result, the sites joined to the inner panel 14 or the hood lock reinforcement 42 are also deformed in the same manner as the collision portion at the frontward side of the collision portion when a collision body collides with the front portion of the hood 10. For this reason, unnecessary front-rear acceleration can be further reduced. Also, because both side wall portions 22H bend (curve) inward of the cross-sectional hat shape with the fold lines 22J as starting points, it becomes easy to control the load in a case where the site of the hood 10 directly above the hood lock reinforcement 42 is pressed. Also, as shown in FIGS. 18A, 19A and 20, the hood lock striker 41 may be directly joined to the front end portion 22E to eliminate the hood lock reinforcement. As a result, the portions where the inner center 22 is joined to the inner front 16 may be eliminated or the portions 22k where the inner center 22 is joined to the inner front 16 may be disposed as positions separated from the hood lock striker 41 as much as possible in the vehicle width direction, or fold lines 22L and 22M along the vehicle body front-ear direction may be formed in both side wall portions 22H, whereby movement of the hood lock striker 41 towards the vehicle width-direction outer sides is not obstructed. In this case, as shown in FIG. 21, when a collision body collides with the site of the hood 10 directly above the hood lock striker 41, the hood lock striker 41 also expands and is deformed in the vehicle width direction when both side wall portions 22H expand and are deformed in the vehicle width direction at the front end portion 22E of the inner center 22. As a result, it becomes easier for both side wall portions 22H to expand in the vehicle width direction at the front end portion 22E of the inner center 22. For this reason, a rise in acceleration can be controlled because the deformation stroke can be lengthened. Also, by eliminating the hood stroke reinforcement, the number of parts can be reduced and the hood lock striker 41 can be pressed via the outer panel 12 and the inner center 22 of the hood 10, whereby the locking of the hood 10 becomes easy and reliable. For this reason, poor locking of the hood 10 can be prevented. Also, as shown in FIGS. 18B and 19B, the front end portion 22E of the inner center 22 may be divided in two, and the leading end portions of the flanges 22G of the inner center 22 may be joined to an upper surface of an upper wall portion 22N formed between the left and right fold lines 22J of the separate member. Also, as shown in FIGS. 22 and 23, the rear end portion 22A of the inner center 22 may extend towards the vehicle body rear from the front flange 18A of the inner rear 18, the upper surface 22F of the inner center 22 may be joined by adhesion or welding to the lower surface 12B of the outer panel 12, and the flanges 22G formed at the open end portion may be joined by adhesion or welding to an upper surface of a rear portion 18D of the inner rear 18. In this case, when a collision body collides with the hood 10 in the vicinity of the rear end portion of the hood 10, local deformation of the outer panel 12 can be suppressed by the rear end portion 22A of the inner center 22. As a result, the outer panel 12 can be prevented from abutting against the rear portion 18D of the inner rear 18 to prevent an unnecessary acceleration from being generated. Also, even in a case where a collision body collides with the hood 10 between adjacent inner centers 22 at the site of the outer panel 12 opposing the inner rear 18, deformation of the outer panel 12 can be suppressed by the adjacent inner centers 22. As a result, the outer panel 12 can be prevented from abutting against the inner rear 18 to prevent an unnecessary acceleration from being generated. Moreover, the rigidity of the hood 10 is improved because the rear end portion 22A of the inner center 22 is disposed between the outer panel 12 and the inner rear 18. Also, as shown in FIGS. 24 and 25, an impact absorbing bracket 50, where the shape seen from the vehicle body front-rear direction is a hat shape where an open portion thereof is oriented downward, may be disposed between the flanges 22G of the inner center 22 and the rear flange 16A of the inner front 16, the flanges 22G of the inner center 22 may be joined by adhesion or welding to an upper wall portion 50A of the impact absorbing bracket 50, and flanges 50B of the impact absorbing bracket 50 may be joined by adhesion or welding to the upper surface of the rear flange 16A of the inner front 16. In this case, because the second moment of area of the inner center 22 is determined by the rigidity in the central vicinity of the hood 10, there is little freedom for the cross-sectional height of the front end portion 22E of the inner center 22, but by disposing the impact absorbing bracket 50, the freedom for the cross-sectional height increases, it becomes possible to enlarge the gap between the outer panel 12 and the inner front 16, unnecessary impact acceleration can be prevented from being generated, and the secondary impact acceleration can be reduced. Also, the shape and plate thickness of the inner front 16 are also determined by the relation between peripheral parts and the torsional rigidity of the hood 10, there is little design freedom for this site and control of the acceleration is impossible, but by adjusting the shape and plate thickness of the impact absorbing bracket 50, control of the acceleration becomes possible. It should be noted that the impact absorbing bracket 50 may also be disposed between the flanges 22G of the inner center 22 and the front flange 18A of the inner rear 18. Also, in the second embodiment, the cross-sectional shape of the inner center 22 is a hat shape where the open portion thereof is oriented downward and one inner center 22 is disposed in the vehicle width-direction center portion of the hood 10; however, instead of this, the cross-sectional shape of the inner center 22 may be a cross-sectional hat shape where the open portion thereof is oriented upward and plural inner centers 22 may be disposed at predetermined intervals in the vehicle width direction as shown in FIG. 15. Moreover, the configuration of the second embodiment (FIGS. 8 to 15) and a combinable configuration of the respective configurations shown in FIGS. 16 to 25 may be singly or plurally selectively combined. Specific embodiments of the invention have been described in detail above, but the invention is not limited to these embodiments. Other various embodiments within the scope of the invention will be apparent to those skilled in the art. Next, a third embodiment of the vehicular hood structure of the invention will be described in accordance with FIGS. 1, 2 and 26. It should be noted that identical reference numerals will be given to members that are the same as those of the first embodiment, and that description of those members will be omitted. The shape, when seen in plan view, of the front end edge portion 18E of the inner rear 18 configuring rear end edge portions 30A of the open portions 30 is an arcuate line shape where the vehicle width-direction center portion thereof is convex towards the vehicle body front. Thus, the rear end edge portions 30A of the open portions 30 are set on an arcuate line where the vehicle width-direction center portion thereof is convex towards the vehicle body front. Next, the operation of the present embodiment will be described. In the present embodiment, the rear end edge portions 30A of the open portions 30 formed in the inner panel 14 are set on the front end edge portion 18E of the inner rear 18, i.e. on an arcuate line where the vehicle width-direction center portion thereof is convex towards the vehicle body front. As a result, when a collision body collides with the vehicle width-direction center portion (impact position P) of the rear portion region of the hood 10, the rear end edge portions 30A of the open portions 30 formed in the inner panel 14 approach lines L joining the impact position P of the collision body on the hood 10 with both vehicle width-direction end portions of the hood rear end, e.g., hood hinge attachment portions (attachment positions Q). Thus, immediately after the collision, the rear portion of the hood 10 including the inner rear 18 can be made to sink towards the vehicle body bottom together with the collision body. For this reason, when a collision body collides with the rear portion region of the hood 10, an unnecessary forward G can be reduced, and the energy absorbing effect with respect to the collision body can be improved. Next, a fourth embodiment of the vehicular hood structure of the invention will be described in accordance with FIGS. 27 to 29. It should be noted that identical reference numerals will be given to members that are the same as those of the third embodiment, and that description of those members will be omitted. As shown in FIG. 27, in the present embodiment, short band-like reinforcement panels 40 respectively serving as reinforcement members are disposed at the rear end edge portions 30A of both open portions 30 at the vehicle width-direction outer sides. Also, long band-like reinforcement panels 42 respectively serving as reinforcement members are disposed at the rear end edge portions 30A of the two open portions 30 at the vehicle-width direction inner sides. As shown in FIG. 28, rear portions 40A of the reinforcement panels 40 are nipped between the outer panel 12 and the front flange 18A of the inner rear 18, and front portions 40B of the reinforcement panels 40 extend inside the open portions 30. As shown in FIG. 29, front-rear direction mid-portions 42A of the reinforcement panels 42 are nipped between the outer panel 12 and the front flange 18A of the inner rear 18, and rear portions 42B of the reinforcement panels 42 are nipped between the outer panel 12 and a rear flange 18F of the inner rear 18. Also, front portions 42C of the reinforcement panels 42 extend inside the open portions 30. Next, the operation of the present embodiment will be described. In the present embodiment, the reinforcement panels 40 and 42 nipped between the inner panel 14 and the outer panel 12 of the hood 10 are disposed along the vehicle body front-ear direction at the rear end edge portions 30A of the open portions 30 at intervals with the left or right inner sides 20 or the inner centers 22. For this reason, when a collision body collides with the hood 10, the generated load of the rear portion region of the hood 10 can be increased virtually without increasing the generated load at the front portion region of the hood 10. As a result, when a collision body collides with the rear portion region of the hood 10, the energy absorbing effect with respect to the collision body can be improved. With respect to the third and fourth embodiments, the invention is not limited to these embodiments. Other various embodiments within the scope of the invention will be apparent to those skilled in the art. For example, although four open portions 30 were formed in the inner panel 14 of the hood 10 in the third and fourth embodiments, the number of the open portions is not limited to four and may be any number, such as one or more. Also, although the inner panel 14 of the hood 10 had a divided structure comprising the inner front 16, the inner rear 18, the inner sides 20 and the inner centers 22, the inner panel 14 of the hood 10 may have another divided structure. The inner panel 14 of the hood 10 may also have an integrated structure. Also, although the band-like reinforcement panels 40 and 42 serving as reinforcement members were used in the fourth embodiment, the reinforcement members are not limited to panels and may be members of cross-sectionally “U” shapes or cross-sectionally hat shapes. Also, as shown in FIG. 30, the reinforcement members (e.g., the reinforcement panels 40 and 42) may be integrally formed with the inner rear 18 configuring the rear end portion of the inner panel 14. Next, an embodiment of a vehicle body front portion structure of the invention will be described in accordance with FIGS. 1, 2, 31. It should be noted that identical reference numerals will be given to members that are the same as those of the first embodiment, and that description of those members will be omitted. The shape, when seen in plan view, of a rear end edge portion 16G of the inner front 16 configuring front end edge portions 30A of the open portions 30 is an arcuate line shape where the vehicle width-direction center portion thereof is concave towards the vehicle body front. In the vehicle body of the present embodiment, as shown in FIG. 31, a length L from the front end edge portions 30A of the open portions 30 to a front portion lower end 40A serving as a terminal end site of the front bumper 40 is a substantially constant L at a side cross-section at all positions in the vehicle width direction, and the length L from the front portion lower end 40A of the front bumper 40 to the front end edge portion 30A of the open portions 30 is a line length of an arcuately line along the outer contour of the vehicle body. The shape, when seen in plan view, of a front end edge portion 16H of the inner front 16 is an arcuate line shape where the vehicle width-direction center portion thereof is convex towards the vehicle body front. Next, the operation of the present embodiment will be described. In the present embodiment, as shown in FIG. 1, the front end edge portions 30A of the open portions 30 formed in the inner panel 14 are set on an arcuate line where the vehicle width-direction center portion thereof is concave towards the vehicle body front. As shown in FIG. 31, in the vehicle body of the present embodiment, the length L from the front end edge portions 30A of the open portions 30 to the front portion lower end 40A of the front bumper 40 are substantially constant at the side cross-section at all positions in the vehicle width direction. As a result, assuming that the height of the front portion lower end 40A of the front bumper 40 from the ground is H, in the present embodiment, the length L+H reaching a road surface R from the front end edge portions 30A of the open portions 30 via the front bumper 40 are substantially constant at the side cross-section at all positions in the vehicle width direction. For this reason, even when a collision body that is long in the vertical direction and is present on the road surface R hits any positions on the front bumper 40 in the vehicle width direction, the length between the position on the hood at which an upper portion of the collision body hits and the front end edge portions 30A of the open portions 30 can be made substantially uniform, whereby the impact load on the upper portion of the collision body can be made uniform when the upper portion of the collision body collides with the front portion region of the hood 10. Also, in the present embodiment, the shape, when seen in plan view, of the rear end edge portion 16G of the inner front 16 has an arcuate line shape where the vehicle width-direction center portion thereof is concave towards the vehicle body front, and the shape, when seen in plan view, of the front end edge portion 16H of the inner front 16 has an arcuate line shape where the vehicle width-direction center portion thereof is convex towards the vehicle body front. Thus, the width of the inner front 16 in the vehicle body front-rear direction becomes substantially constant. As a result, the yield at the time of molding the inner front 16 is improved, productivity is improved, transportation and storage space are reduced, and it becomes possible to reduce transportation costs and management costs. A specific embodiment of the vehicle body front portion structure has been described in detail, but the invention is not limited to this embodiment. That other various embodiments within the scope of the invention are possible will be apparent to those skilled in the art. For example, although four open portions 30 were formed in the inner panel 14 of the hood 10 in the embodiment of the vehicle body front portion structure, the number of the open portions is not limited to four and may be any number, such as one or more. Also, in the embodiment of the vehicle body front portion structure, although the inner panel 14 of the hood 10 had a divided structure comprising the inner front 16, the inner rear 18, the inner sides 20 and the inner centers 22, the inner panel 14 of the hood 10 may have another divided structure. The inner panel 14 of the hood 10 may also have an integrated structure.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a vehicular hood structure and a vehicle body front portion structure, and in particular to a vehicular hood structure and a vehicle body front portion structure that protects a collision body at the time of a collision in a vehicle such as an automobile. 2. Description of the Related Art Conventionally, with respect to a vehicular hood structure that protects a collision body at the time of a collision in a vehicle such as an automobile, a configuration is known where one inner member formed by press molding is integrated with an outer member by hemming, and a lock reinforcement is attached between the outer member and the inner member at a hood lock striker support portion (e.g., see Japanese Patent Application Laid-Open Publication (JP-A) No.11-321714). A configuration is also known where the thickness of an aluminium alloy serving as the outer member is 0.5 mm to 2.0 mm and a reinforcement member that lines the outer member is about 3 mm to 15 mm (e.g., see JP-A No.2001-191962). A configuration including an annularly-formed outer frame and an inner skeletal member that bridges the outer frame along the vehicle body front-rear direction is also known (e.g., see JP-A No. 6-72355). A configuration where the lock reinforcement includes walls extending in the vehicle body front-ear direction at the left and right sides of a hood lock striker is also known (e.g., see JP-A No.6-312670). A configuration where the inner member comprises an annular frame skeleton and an inner skeleton that forms a closed cross section by being coupled to the frame skeleton inward of the frame skeleton, and where the longitudinal walls of the cross section are substantially vertical surfaces, is also known (e.g., see JP-A No. 5-278637). A configuration where the side end portions of the hood curve back inward and end portions hang down is also known (e.g., see JP-A No. 2001-301541). However, with respect to the technology of JP-A No. 11-321714, the production costs are high because the inner member is a large pressed part. Also, because the closed cross section, which is formed by the outer member and the inner member and extends in the vehicle body front-rear direction and the vehicle width direction, and the lock reinforcement are disposed, deformation of the hood for absorbing impact when a collision body collides with the hood is obstructed, a reaction force in the vehicle body front-rear direction is generated, and the impact absorbing efficiency is lowered. With respect to the vehicular hood structure ( FIGS. 4 and 8 ) of JP-A No. 11-321714, a configuration is known where, in an automobile hood (also called a bonnet) where an inner panel (also called an inner frame) is integrated with an outer panel, a reinforcement panel attached to the inner panel is folded in the shape of Mt. Fuji by a front slanted panel, a top panel and a rear slanted panel, with a slit being disposed in the top panel so that the top panel is divided into a front top panel and a rear top panel, and edge reinforcement members that reinforce the edges of the front top panel and the rear top panel are attached to the front top panel and the rear top panel, whereby, when a collision body hits the vicinity of the attachment portion of the striker from the outer panel side, the outer panel is deformed, the outer panel is received by the edge reinforcement members respectively disposed at the front top panel and the rear top panel, the energy of the collision body is initially absorbed, and then the front slanted panel and the rear slanted panel secondarily absorb the energy of the flexing obstacle. However, in JP-A No.11-321714, the reinforcement panel is disposed in the front portion region of the hood. As a result, when a collision body collides with the rear portion region of the hood, the reinforcement panel has no energy absorbing effect with respect to the collision body. Moreover, in the vehicle body front portion structure ( FIGS. 5, 6 and 7 ) of JP-A No. 11-321714, a configuration is known where, with respect to an automobile hood where the inner panel is integrated with the outer panel, the inner panel is one molded part that is press-molded, and an open portion is formed in the inner panel in order to reduce weight and improve hood rigidity. However, in JP-A No. 11-321714, the closed cross-sectional structure is formed by adhering the edge portion of the open portion of the inner panel to the undersurface of the outer panel, and although hood rigidity is improved, the collision load on the collision body is not uniform, regardless of differences in the vehicle width direction of the collision positions, when a collision body collides with the front portion region of the hood.
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<SOH> SUMMARY OF THE INVENTION <EOH>In consideration of the above-described facts, it is an object of the present invention to provide a vehicular hood structure with which it is possible to improve impact absorbing efficiency and lower production costs. It is another object of the invention to provide a vehicular hood structure that can improve energy absorbing efficiency with respect to a collision body when a collision body collides with the rear portion region of a hood. It is yet another object of the invention to provide a vehicle body front portion structure that can make uniform a collision load on a collision body, regardless of differences in the vehicle width direction of collision positions, when a collision body collides with the front portion region of a hood. A first aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, and a front-rear direction inner member that is disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member and which bridges the front end portion inner member and the rear end portion inner member. Thus, because the inner member of the hood is divided into the front end portion inner member, the rear end portion inner member and the front-ear direction inner member, the inner member can be divided into plural long parts. As a result, progressive molding becomes possible and production yield increases. As a result, material costs, mold costs and processing costs of the hood can be reduced, and it becomes possible to reduce production costs. Also, because the front-rear direction inner member is disposed along the vehicle body front-ear direction between the front end portion inner member and the rear end portion inner member, when a collision body collides with the hood, deformation of the hood for absorbing the impact is smoothly carried out and a reaction force in the vehicle body front-rear direction is not generated. As a result, the impact absorbing efficiency can be improved A second aspect of the invention provides the vehicular hood structure of the first aspect, wherein respective couplings between the hood outer member, the front end portion inner member, the rear end portion inner member and the front-rear direction inner member are couplings in a separation (peeling) direction and a shearing direction. Thus, in addition to the content of the first aspect, in both the separation direction and the shearing direction, the strength of the respective couplings between the hood outer member, the front end portion inner member, the rear end portion inner member and the front-rear direction inner member is improved, whereby sufficient joint strengths can be obtained even in joints resulting from adhesion. A third aspect of the invention provides the vehicular hood structure of the first aspect, wherein a surface of the front-rear direction inner member opposing the outer member is smoothly formed, has a shape along (according to) an undersurface of the outer member and extends as far as front and rear ends of the outer member. Thus, in addition to the content of the first aspect, in the vicinity of the front and rear end portions of the hood, by making flatly smooth the cross section of the surface of the front-ear direction inner member opposing the outer member, when a collision body collides with the hood, the possibility to generate an unnecessary deceleration load in the front-rear direction with respect to the collision body can be reduced. A fourth aspect of the invention provides the vehicular hood structure of the first aspect, wherein a front end portion of the front-ear direction inner member extends above a hood lock or a hood stopper. Thus, in addition to the content of the first aspect, because the front-rear direction inner member that generates an excellent collision acceleration is disposed above the hood lock or the hood stopper, an excellent collision acceleration can be generated even at a position above the hood lock or the hood stopper, where control of the collision load has conventionally been difficult. A fifth aspect of the invention provides the vehicular hood structure of the third aspect, wherein a front end portion of the front-rear direction inner member is nipped and joined between the outer member and the front end portion inner member, and a rear end portion of the front-rear direction inner member is nipped and joined between the outer member and the rear end portion inner member. Thus, in addition to the content of the third aspect, because each front-rear direction inner member disposed between the front end portion inner member and the rear end portion inner member has a dual supported beam structure, the timing of the load generation can be quickened. A sixth aspect of the invention provides the vehicular hood structure of the third aspect, wherein side wall portions of a front end portion of the front-rear direction inner member are joined to one of the front end portion inner member or a lock reinforcement. Thus, in addition to the content of the third aspect, because the front-rear direction inner member has a dual supported beam structure, the timing of the load generation can be quickened. A seventh aspect of the invention provides the vehicular hood structure of the third aspect, wherein lower portions of left and right side walls of the front-ear direction inner member are joined to correspond to at least one of end portions of a hood lock striker. Thus, in addition to the content of the third aspect, when a collision body collides with the hood directly above the hood lock striker, the cross section of the inner member expands in the vehicle width direction and is deformed. As a result, it becomes possible to control the deformation mode of the inner member using the load where both end portions of the hood lock striker are deformed so that they relatively move away from each other in the vehicle width direction. An eighth aspect of the invention provides the vehicular hood structure of either of the sixth or seventh aspects, wherein a stepped portion including a fold line in the vehicle body front-rear direction is formed in the side wall portion of the front-rear direction inner member. Thus, in addition to the content of either of the sixth or seventh aspects, the stepped portion including the fold line is disposed, whereby rapid change of geometrical moment of inertia (second moment of area) can be alleviated. A ninth aspect of the invention provides the vehicular hood structure of the first aspect, wherein front and rear end portions of the front-rear direction inner members plurally disposed at predetermined intervals in the vehicle width direction are nipped and joined between the outer member and the front end portion inner member and the outer member and the rear end portion inner member, and between adjacent joint portions, gaps are formed between the outer member and the front end portion inner member and the outer member and the rear end portion inner member. Thus, in addition to the content of the first aspect, control is effected, due to the flatly smooth surfaces of the front-rear direction inner members, so that an unnecessary collision acceleration is not generated at the portions where the front-rear direction inner members are present. Further, due to that gaps are formed between the outer member and the front end portion inner member and the outer member and the rear end portion inner member, between adjacent joint portions, the generation of an unnecessary acceleration for which there is the possibility for the front and rear end portions of the front end portion inner member and the rear end portion inner member to be joined to the inner surface of the outer member can be prevented. A tenth aspect of the invention provides the vehicular hood structure of either of the first or ninth aspect, wherein an impact absorbing bracket is provided (intervened) between, at least one of a lower surface of the front-rear direction inner member and an upper surface of the front end portion inner member and the lower surface of the front-rear direction inner member and an upper surface of the rear end portion inner member. Thus, in addition to the content of either of the first or ninth aspect, geometrical moment of inertia (second moment of area) of the front-rear direction inner member is determined by the rigidity required in the hood center region. For this reason, there is little freedom for the cross-sectional height of the front-rear direction inner member in the vicinity of the front and rear end portions, but by intervening the impact absorbing bracket, it becomes possible to generate a desired load (reaction force). An eleventh aspect of the invention provides the vehicular hood structure of the first aspect, wherein a recessed portion formed in a front portion of the rear end portion inner member is partially or completely closed off by the front-rear direction inner member. Thus, in addition to the content of the first aspect, an elastic deformation mode resulting from the recess can be eliminated, and the generation of a reaction force can be promptly launched A twelfth aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes at least one open portion formed in the inner member, with a rear end edge portion of the open portion at a hood rear portion being set on an arcuate line where a vehicle width-direction center portion thereof is convex towards the vehicle body front. Thus, the rear end edge portion at the hood rear portion of the at least one open portion formed in the inner member is set on an arcuate line where a vehicle width-direction center portion thereof is convex towards the vehicle body front. Thus, when a collision body collides with the vehicle width-direction center portion of the rear portion region of the hood, the rear end edge portion of the open portion formed in the inner member approaches lines joining the impact position of the collision body on the hood with both vehicle width-direction end portions of the hood rear end. Thus, immediately after the collision, the rear portion of the hood including the inner member can be made to sink towards the vehicle body bottom together with the collision body. For this reason, when a collision body collides with the rear portion region of the hood, an unnecessary forward G can be reduced, and the energy absorbing effect with respect to the collision body can be improved. A thirteenth aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, a plurality of front-rear direction inner members that are disposed along the vehicle body front-ear direction between the front end portion inner member and the rear end portion inner member and which bridge the front end portion inner member and the rear end portion inner member, at least one open portion formed in the inner member, and at least one reinforcement member disposed along the vehicle body front-ear direction at a rear end edge portion of the open portion at a hood rear portion at interval with the plurality of front-ear direction inner members between the plurality of front-ear direction inner members. Thus, because at least one reinforcement member (preferably, reinforcement members) is disposed along the vehicle body front-ear direction at the rear end edge portion of the open portion at the hood rear portion at intervals with the left and right front-ear direction inner members, when a collision body collides with the hood, the generated load of the rear portion region of the hood can be increased virtually without increasing the generated load at the front portion region of the hood. As a result, when a collision body collides with the rear portion region of the hood, the energy absorbing effect with respect to the collision body can be improved. A fourteenth aspect of the invention provides a vehicle body front portion structure comprising: a vehicular hood comprising a hood outer member configuring a vehicle body outer side surface and a hood inner member that is disposed at the inner side of the outer member and includes at least one open portion; and a front bumper, wherein at a side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from a terminal end site of the front bumper to a front end edge portion of the open portion is substantially constant. Thus, at the side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from the terminal end site of the front bumper to the front end edge portion of the open portion of the inner member that is disposed at the inner side of the outer member of the vehicular hood and includes at least one open portion is substantially constant. Thus, even when a vertically long collision body hits any position in the vehicle width direction of the front bumper, the length between the position on the hood upper surface at which the uppermost portion of the collision body hits and the front end edge portion of the open portion can be made substantially uniform. As a result, when a collision body collides with the front portion region of the hood, the collision load on the collision body can be made uniform regardless of differences in the vehicle width direction of the collision position. A fifteenth aspect of the invention provides the vehicle body front portion structure of the fourteenth aspect, wherein the length from the terminal end site of the front bumper to the front end edge portion of the open portion is a line length of an arcuate curved line along the outer contour of the vehicle body. Thus, at the side cross-section of all positions in the vehicle width direction of the vehicle body front portion, the length from the terminal end site of the front bumper to the front end edge portion of the open portion of the inner member that is disposed at the inner side of the outer member of the vehicular hood and includes at least one open portion is a line length of an arcuate curved line along the outer contour of the vehicle body and is substantially constant. Thus, even when a vertically long collision body hits a position in the vehicle width direction of the front bumper, the length between the position on the hood upper surface at which the uppermost portion of the collision body hits and the front end edge portion of the open portion can be made substantially uniform. As a result, when a collision body collides with the front portion region of the hood, the collision load on the collision body can be made uniform regardless of differences in the vehicle width direction of the collision position. A sixteenth aspect of the invention provides a vehicular hood structure comprising an outer member configuring a vehicle body outer side surface of a hood and an inner member disposed at the inner side of the outer member, wherein the vehicular hood structure includes a front end portion inner member configuring a front end portion of the inner member, a rear end portion inner member configuring a rear end portion of the inner member, front-rear direction inner side members that are disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member at sides portions and which bridge the front end portion inner member and the rear end portion inner member, and at least one front-rear direction inner center member that is disposed along the vehicle body front-rear direction between the front end portion inner member and the rear end portion inner member and which bridges the front end portion inner member and the rear end portion inner member. A seventeenth aspect of the invention provides the vehicular hood structure of the eighth aspect, wherein at a coupling portion of the front-rear direction inner member, the front-rear direction inner member is coupled via another member. An eighteenth aspect of the invention provides the vehicular hood structure of the thirteenth aspect, wherein the at least one reinforcement member is formed integrally with the rear end portion inner member.
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20040630
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20060530
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20050106
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81016.0
| 0
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MORROW, JASON S
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VEHICULAR HOOD STRUCTURE AND VEHICLE BODY FRONT PORTION STRUCTURE
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,879,824
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ACCEPTED
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Internal connection dental implant
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An internal connection dental implant and implant assembly in which the implant includes a lobed configuration for installing the implant and a beveled surface positioned on the proximal side of the lobed configuration for providing stability between the implant and a corresponding abutment.
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1. A dental implant comprising: a body having a longitudinal axis, a distal end and an open proximal end; implant retaining means provided on an external portion of said body; an internal bore provided within a portion of said body, said internal bore having a proximal end at the open proximal end of said body and a distal end; a first portion of said internal bore comprising an internally facing surface having a proximal end and a distal end, said surface extending from near the proximal end of said internal bore toward the distal end of said internal bore, said surface being beveled inwardly toward its distal end at an angle of about 8° to about 40° relative to said longitudinal axis; a second portion of said internal bore comprising an internally facing drive region positioned between the distal end of said surface and the distal end of said internal bore; and a third portion of said internal bore comprising an internally threaded region positioned within said drive region and the distal end of said internal bore. 2. The dental implant of claim 1 wherein said surface is a substantially frustoconical surface beveled toward its distal end at an angle of about 8° to about 30°. 3. The dental implant of claim 2 wherein said surface is beveled toward its distal end at an angle of about 8° to about 20°. 4. The dental implant of claim 1 wherein said surface is a substantially frustoconical surface having a diametrical dimension at its proximal end and a length dimension, said diametrical dimension being measured in a direction perpendicular to said longitudinal axis and said length dimension being measured in a direction parallel to said longitudinal axis, wherein said length dimension ranges from about 15% to about 40% of said diametrical dimension. 5. The dental implant of claim 4 wherein said length dimension ranges from about 15% to about 25% of said diametrical dimension. 6. The dental implant of claim 5 wherein said surface is beveled toward its distal end at an angle of about 8° to about 20°. 7. The dental implant of claim 1 wherein said internal wrench engaging portion includes a plurality of concave lobes and a plurality of convex lobes alternating with said concave lobes, the radially outermost points of each of said concave lobes lying on a circle defining a major diameter and the radially innermost points of each of said convex lobes lying on a circle defining a minor diameter. 8. The dental implant of claim 7 wherein a portion of each of said concave lobes has a circular configuration and a portion of each of said convex lobes has a circular configuration. 9. The dental implant of claim 7 wherein said minor diameter is about 60% to about 90% of said major diameter. 10. The dental implant of claim 7 wherein a portion of each of said concave lobes has an elliptical configuration and a portion of each of said convex lobes has an elliptical configuration. 11. The dental implant of claim 7 wherein said each of plurality of concave lobes is of the same size and configuration as each of said plurality of convex lobes. 12. The dental implant of claim 4 wherein said internal wrench engaging portion includes a plurality of concave lobes and a plurality of convex lobes alternating with said concave lobes, the radially outermost points of each of said concave lobes lying on a circle defining a major diameter and the radially innermost points of each of said convex lobes lying on a circle defining a minor diameter and wherein said major diameter is about 60% to about 90% of said diametrical dimension. 13. A dental implant comprising: a body having a longitudinal axis, a proximal end and a distal end; implant retaining means provided on an external portion of said body; an internal bore provided within a portion of said body, said internal bore having a proximal end at the proximal end of said body and a distal end; an internally facing surface having a proximal end and a distal end, said surface extending from near the proximal end of said internal bore toward the distal end of said internal bore, said surface being beveled inwardly toward its distal end; an internally facing drive region positioned within said internal bore between the distal end of said surface and the distal end of said internal bore, said drive region including a plurality of concave lobes and a plurality of convex lobes alternating with said concave lobes, the radially outermost points of each of said convex lobes lying on a circle defining a major diameter and the radially innermost points of each of said concave lobes lying on a circle defining a minor diameter, said plurality of concave lobes being of the same size and configuration as said plurality of convex lobes; and an internally threaded portion positioned within said internal bore and between said drive region and the distal end of said body. 14. The dental implant of claim 13 wherein a portion of each of said concave lobes has a circular configuration and a portion of each of said convex lobes has a circular configuration. 15. The dental implant of claim 13 wherein a portion of each of said concave lobes has an elliptical configuration and a portion of each of said convex lobes has an elliptical configuration. 16. The dental implant of claim 13 wherein said minor diameter is about 60% to about 90% of said major diameter. 17. The dental implant of claim 13 wherein said surface is a substantially frustoconical surface beveled toward its distal end at an angle of about 8° to about 30° relative to said longitudinal axis. 18. The dental implant of claim 17 wherein said surface is beveled toward its distal end at an angle of about 8° to about 20° relative to said longitudinal axis. 19. The combination of a dental implant of claim 1 and an abutment connectable to said implant wherein said abutment has a proximal end and a distal end and comprises: a first abutment surface engaging said surface when said dental implant and said abutment are connected; a second abutment surface corresponding to and adjacent to said drive region when said dental implant and said abutment are connected; a prosthesis mounting portion; a central bore extending through at least a portion of said prosthesis mounting portion and to the distal end of said abutment; and an abutment screw extending through said central bore and into said internally threaded bore when said dental implant and said abutment are connected.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to the field of dental implants and more specifically to an internal connection implant. The invention also relates to the combination of an internal connection implant and a complementary abutment. 2. Description of the Prior Art A wide variety of dental implants currently exists in the art. Such dental implants commonly include a body with external threads for mounting and retaining the implant within the patient's mouth. Installation of the implant involves rotation of the implant into a predrilled or tapped site using a drive member such as a ratchet or other rotation means. The implant also includes a drive region which may be located externally or internally. Various structures for both externally and internally driving the implant currently exist. While many internally driven dental implants provide satisfactory torque transfer and stability between implant and abutment, implant connection failures continue to exist. Accordingly, there is a continuing need for an internal connection or internally driven implant which provides improved torque transfer and implant/abutment stability, with a structure that can also minimize implant connection failure. SUMMARY OF THE INVENTION The present invention relates to a dental implant and combination dental implant and abutment assembly and more specifically to an internal connection dental implant and combined internal connection implant and abutment assembly. In general, the dental implant of the present invention includes a drive or indexing region which equalizes the stress distribution and provides for increased torque carrying capacity across the entire implant connection, thereby providing a drive means which minimizes implant connection failures and which is usable for all sizes of implants. The implant in accordance with the present invention also includes a stabilizing region which provides the implant and abutment with a highly stable connection. In the preferred embodiment, the drive and indexing region includes a plurality of equally dimensioned and equally configured concave and convex lobes which are positioned between a minor diameter and a major diameter. This lobed configuration provides increased surface area for contact with a wrench or other drive means during installation, as well as providing an outer implant wall of sufficient thickness to improve resistance to implant connection failures, particularly when accommodating off-axis loading. In the preferred embodiment, the stabilizing region for minimizing relative movement, so called micromotion, between the implant and a corresponding abutment, and thus improving stability between the implant and such abutment, includes a beveled surface positioned between the drive and indexing section and the proximal end of the implant. This beveled surface mates with a corresponding beveled surface of the abutment. The angle of this beveled surface is sufficient to form a friction fit so as to stabilize the interface between the implant and the abutment. Accordingly, it is an object of the present invention to provide an internal connection dental implant and assembly facilitating improved rotational or drive torque, while at the same time minimizing failures of the implant connection during installation and use. Another object of the present invention is to provide an internal connection dental implant and assembly which provides stability between the implant and the corresponding abutment. These and other objects of the present invention will become apparent with reference to the drawings, the description of the preferred embodiment and the appended claims. DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric, broken apart view showing the dental implant assembly in accordance with the present invention. FIG. 2 is a view, partially in section, of the dental implant assembly of FIG. 1 in its assembled form as viewed along a plane cut through its longitudinal center. FIG. 3 is a plan view as viewed from the proximal end of the dental implant in accordance with the present invention. FIG. 4 is a view, partially in section, as viewed along the section line 4-4 of FIG. 3. FIG. 5 is a view, partially in section, as viewed along the section line 5-5 of FIG. 3. FIG. 6 is an enlarged, fragmentary view, partially in section, of the proximal end portion of the dental implant in accordance with the present invention. FIG. 7 is a further embodiment of a lobed configuration for the dental implant in accordance with the present invention. FIG. 8 is an elevational view of one embodiment of an abutment in accordance with the present invention as viewed from the distal end of the abutment. FIG. 9 is a view, partially in section, of the abutment of FIG. 8 as viewed along the section line 9-9 of FIG. 8. FIG. 10 is an enlarged, fragmentary side view of the distal end portion of the abutment of FIGS. 8 and 9 in accordance with the present invention. FIG. 11 is an enlarged, fragmentary view, partially in section, showing the relationship between the dental implant and abutment in the area of the stabilizing region. FIG. 12 is an enlarged, fragmentary view, partially in section, showing the relationship between the dental implant and the abutment in the area of the distal end of the abutment and the drive region. FIG. 13 is an isometric, broken apart view of a direct drive tool for installing the dental implant in accordance with the present invention. FIG. 14 is a view, partially in section, of the tool of FIG. 13 being used to rotate an implant. FIG. 15 is an isometric, broken apart view of a fixture mount assembly for installing the dental implant in accordance with the present invention. FIG. 16 is a view, partially in section, of the fixture mount assembly of FIG. 15 in preassembled form within an implant. DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is directed to a dental implant and a dental implant assembly and more specifically to an internal drive or internal connection implant and a corresponding dental implant assembly. Reference is first made to FIGS. 1 and 2 showing the dental implant assembly 10 in broken apart form (FIG. 1) and in assembled or connected form (FIG. 2). The dental assembly 10 includes a dental implant 11, an abutment 12 and an abutment or connection screw 14. The dental implant 11 includes a distal end 15, a proximal end 16, a body portion 13 and a plurality of external threads 18 on the body. The abutment includes a distal end 19, a proximal end 20 and an internal connection bore or opening 17. The connection screw 14 includes a distal end 21 and a proximal end 23. The screw 14 is provided with a plurality of external threads 24 near its distal end 21 and a head 22 near its proximal end 23. The head 22 is provided with wrench engaging means 25 such as an internal hex, an internal square or other driving surface. Reference is next made to FIGS. 3, 4, 5 and 6 showing various views of the dental implant 11. The implant 11 includes a distal end 15, a proximal end 16 and an implant retaining means in the form of the external threads 18 on the outer surface of the implant. These threads 18 facilitate installation of the implant and anchor and retain the implant in the jawbone of the patient following installation. While the preferred embodiment shows the implant retaining means as comprising a single continuous thread 18 over a substantial portion of the outer surface of the implant, such retaining means can include any retaining means currently known in the art or hereinafter known in the art including, but not limited to, multiple threads, tapered threads, alternating threads of different heights, or retaining means which do not comprise threads. The implant 11 further includes an outer wall portion 26 located near the proximal end 16. As shown in FIGS. 4 and 5, the wall 26 is defined by an outer, unthreaded, generally cylindrical surface 28 and an inner surface 29. The surface 29 defines, and is defined by, the internal lobed configuration hereinafter described. Because the surface 29 defines both convex and concave lobes as described below, the thickness of the wall 26 will vary from thin wall sections as shown in FIG. 4 to thick wall sections as shown in FIG. 5. The outer diametrical dimension of the wall portion 26 defines the diameter of the implant in this particular region of the implant. The interior of the implant 11 includes a stabilizing region 30, a drive and indexing region 31 and an internally threaded bore 32. The region 30 begins at or near the surface 34 and ends at the point 33 where it transitions into the drive and indexing region 31. The region 31, in turn begins at or about the point 33 and ends at its distal end 42. An accommodation region 44 is provided between the distal end 42 and the bore 32. The bore 32 extends from the region 44 toward the distal end 15 of the implant 11. The internal threads of the bore 32 compliment and receive the external threads 24 of the screw 14 when the implant 11, the abutment 12 and screw 14 are in their assembled position as shown in FIG. 2. As shown best in FIGS. 3 and 6, the proximal end 16 of the implant 11 is provided with a generally annular proximal surface 34 which defines the top of the wall portion 26. If desired, this surface may be provided with radiused edges. An interior beveled surface 35 extends from the surface 34 toward the distal end 15 of the implant. This surface 35 by itself and in combination with a corresponding surface in the abutment forms the stabilizing region 30 of the implant. The surface 35 is an internal, substantially frustoconical surface which slopes inwardly as it extends toward the distal end 15 at an angle “A” relative to the longitudinal center line 36 of the implant 11 and the combined implant/abutment assembly. The surface 35 preferably extends for a distance which is about 10 to 40% of the implant diameter in the drive or indexing region 31 as described above, more preferably about 15 to 30% of such implant diameter, and most preferably about 15 to 25% of such implant diameter. As indicated above, the surface 35 slopes inwardly toward the distal end 15 at the angle “A”. This angle can be any angle which functions to form a friction fit with a corresponding surface of the abutment as described below and thus lock and/or stabilize the implant 11 with the abutment 12. Preferably, however, this angle “A” is about 8° to about 40°, more preferably about 8° to about 30° and most preferably about 8° to about 20°. The angle “A” as shown in FIG. 6 is about 12°. Further, this angle “A” is preferably greater than the angle of a “Morse taper” and less than 45°. The drive and indexing region 31 of the implant is comprised of a lobe configuration having a plurality of internally facing lobes which includes a plurality of outwardly extending or concave lobes 38 and a similar number of inwardly extending convex lobes 39. In the preferred embodiment, the concave lobes 38 (as well as the convex lobes 39) are angularly spaced from one another by 60°. Thus, in the preferred embodiment, there are six concave lobes 38 and six convex lobes 39. Both the concave lobes 38 and the convex lobes 39 are defined by portions of circles, with the transition between the concave lobes 38 and the convex lobes 39 being comprised of arcs tangent to the circle of each concave lobe 38 and its adjacent convex lobe 39. Still further, it is preferable for the circles which form portions of the concave lobes 38 and the circles which form portions of the convex lobes 39 to be nominally, and thus substantially, of the same radius. Specifically, while the radii of both the concave lobes 38 and the convex lobes 39 in the preferred embodiment are designed and intended to be nominally the same, the radii of one of the lobes 38 or 39 is slightly larger and the other is slightly smaller than the nominal radius to accommodate manufacturing and other tolerances and to assure clearance, when assembled. With reference to FIG. 3, a circle intersecting the outermost points of each of the concave lobes 38 forms an outer or major diameter of the lobe configuration. A circle which intersects the innermost points of each of the convex lobes 39 forms an inner or minor diameter of the lobed configuration. Preferably, the difference between the major 40 and minor 41 diameters is kept as small as possible, while still providing sufficient torque transfer to rotate and thus install the implant into the jaw bone of a patient and to also withdraw the implant, if needed. Because the minor diameter 41 must be greater than the outermost diameter of the threaded portion 32 to allow the threaded portion 24 of the screw to pass, minimizing the diametrical difference between the major 40 and minor 41 diameters minimizes the major diameter 40 and thus maximizes the thickness of the implant wall portion 26. This in turn maximizes the strength of the implant 11 and reduces implant connection failures, both during installation and during use. This reduction in failures is particularly applicable for situations involving off-axis loading. Preferably the minor diameter 41 is about 60% to 90% of the major diameter 40, more preferably about 70% to 90% and most preferably about 80% to 90%. As shown best in FIG. 6, the drive and indexing region 31 extends from the point 33 to its distal end 42. The point 33 defines the transition from the region 30 to the region 31 and thus the distal or ending point of the surface 35 and the beginning or proximal end of the lobe configuration. Preferably, each of the lobes 38 and 39 extends from its proximal end 33 to its distal end 42 along substantially parallel lines. Thus, the surfaces of the lobes 38 and 39 defined by the inner surface 29 of the wall 26 extend substantially parallel to the longitudinal axis 36 of the implant. Preferably, the length of the surface 29 defining the lobes 38 and 39 between the point 33 and the distal end 42 is about twice the length of the surface 35. Further, the length of the surface 29 is preferably about 20 to 60% of the implant diameter in the drive or indexing region 31, more preferably about 25 to 50% of such implant diameter and most preferably, about 30 to 40% of such implant diameter. Accordingly, in the preferred embodiment, the drive and indexing region 31 comprises a plurality of outwardly extending concave lobes 38 and a plurality of inwardly extending or convex lobes 39. These lobes 38 and 39 are portions of circles having substantially the same or similar radii and have side walls defined by the surface 29 which are substantially parallel to each other and to the longitudinal axis 36 of the implant. The minor diameter 41 of the lobe configuration is greater than the diameter of the internally threaded bore 32 and the difference between the minor diameter 41 and the major diameter 40 should be kept as small as possible, while still providing sufficient torque transferability to install the implant and to remove it, if needed. This structure provides an outer wall 26 of increased diameter to resist, and thus reduce, implant connection failure during installation or use, regardless of the implant size and particularly when in situations involving off-axis loading. Although the preferred lobe configuration comprises a plurality of concave lobes 38 and complimentary convex lobes 39 formed of portions of substantially equal radii, certain advantages of the present invention can also be achieved by lobed configurations which are formed of circles with unequal radii or formed of configurations other than circles. For example, convex and concave lobes which are formed as portions of ellipses are also contemplated. Such a configuration is shown in FIG. 7 in which the outwardly extending concave lobes 38a and the inwardly extending convex lobes 39a are defined by portions of ellipses. In these alternate configurations, the corresponding configurations of the loads on the abutment and the drive tools and placement heads are similarly altered. Reference is next made to FIGS. 8, 9 and 10 showing one form of an abutment 12 usable with the implant 11. The abutment 12 includes a region 45 corresponding to the implant region 31. This region 45 includes a lobed configuration comprised of a plurality of externally facing lobes including a plurality of outwardly extending convex lobes 46 which compliment, and are designed for engagement with, the concave lobes 38, and a plurality of concave lobes 48 which compliment, and are designed for engagement with, the convex lobes 39. Thus, when assembled as shown in FIGS. 1 and 2, the lobed configuration 45 of the abutment is designed for insertion into and seating within the lobed configuration of the region 31. The dimensions of the lobes 46 and 48, including their major and minor diameters, approximate or are slightly smaller than the major 40 and minor 41 diameters of the lobes 38 and 39. Also, like the lobed configuration of the region 31, the lobes 46 and 48 have side walls which extend substantially parallel to each other and substantially parallel to the longitudinal axis 36 of the implant assembly. Preferably, the length of the lobes 46 and 48 between their proximal end 49 and their distal end 50 is slightly shorter than the corresponding length of the lobes 38 and 39. Thus the lobes 46 and 48 are designed to slide into the lobes 38 and 39, respectively, in relatively close tolerances. The distal end 19 of the abutment 12 includes and is defined by a lead-in portion or region 53 which includes the beveled lead-in surface 51. This lead-in surface 51 helps to guide the lobed configuration 45 of the abutment 12 into the lobed configuration region 31 of the implant 11. When the abutment and implant are in assembled form as shown in FIG. 2, the lead-in region 53 and the surface 51 are accommodated within the accommodation section 44 (FIGS. 2, 6 and 12). A locking or stabilizing portion 57 of the abutment 12 is positioned adjacent to the proximal end 49 of the lobed configuration 45 and extends from that end 49 to the end 54. This portion 57 includes a beveled surface 52 which bevels inwardly from its proximal end 54 toward the end 49. This surface 52 is an external, substantially frustoconical surface which forms an angle “B” with the center line 36 of the implant and the implant assembly when assembled. Preferably, this angle “B” is the same as angle “A”, however, certain advantages of the present invention can be achieved with angles “A” and “B” which are different from one another. Preferably, however, the angle “B” is about 8 to 40°, more preferably about 8 to 30° and most preferably about 8 to 20°. Extending outwardly from the proximal end 54 of the surface 52 abutment is a shoulder which includes a distal facing surface 55. This surface 55 has a generally annular configuration with radiused corners. In some abutment configurations, the shoulder can be eliminated. When the abutment 12 is assembled within the implant 11, as shown best in FIGS. 2 and 11, the surfaces 52 and 35 engage one another in a friction fit engagement. The friction fit between the beveled surfaces 52 and 35 provides a tapered locking engagement between these two surfaces. This provides stability between the abutment 12 and the implant 11 to preclude or reduce any rocking or micromotion between the abutment 12 and the implant 11. The abutment 12 further includes a main body portion 58 between the section 57 and the proximal end 20. This body 58 supports the prosthetic tooth or other appliance. A throughhole or bore 17 extends through a portion of the body 58 and through the stabilizing portion 57, the lobed configuration 45 and the lead-in region 53. The throughhole 17 is defined at its proximal end by the bore 59 and at its distal end by the bore 60. The bores 59 and 60 are joined by the abutment screw support shoulder 61. When the abutment is assembled and installed in a patient as shown in FIG. 2, the abutment screw 14 extends through the bore 17, with its external threads 24 engaging the internal threads 32 of the implant 11. The head 22 of the screw 14 includes a shoulder portion which mates with and seats against the shoulder 61 of the abutment. As the abutment screw 14 is advanced against the shoulder 61, the surface 52 is forced into and against the surface 35, with the lobed configuration 45 of the abutment positioned within the lobed configuration 31 of the implant. The embodiment of the abutment shown in FIGS. 8, 9 and 10 is a pre-angled abutment which results in off-axis loading. Thus, the throughhole 17 is aligned with the abutment sections 53, 45 and 57 and the longitudinal axis 36 of the implant when assembled, but is not fully aligned with the body portion 58 of the abutment. Abutments can assume various configurations, including pre-angled abutments with various angles and straight abutments which are not provided with or intended for off-axis mounting. In these straight abutments, the throughhole 17 would extend through the distal end 20 of the abutment. FIGS. 13-16 show two embodiments of drive means for installing the implant 11. Specifically, FIGS. 13 and 14 illustrate a direct drive embodiment, while FIGS. 15 and 16 illustrate an implant with a preassembled fixture mount. With reference to FIGS. 13 and 14, the direct drive includes a guide portion 66, a drive portion 65, a surface portion 68 and a rotation region 69. The guide portion 66 comprises a generally cylindrical, unthreaded structure extending generally parallel to the longitudinal axis of the drive member 63. The region 65 comprises a lobed configuration substantially matching the lobed configuration 45 of the abutment (FIG. 9) so that when the drive member 63 is inserted into the implant 11 and rotated, the lobed configuration 65 mates with and engages the lobed configuration 31 in driving relationship. The rotation portion 69 may comprise a hex, a square or any other means to which a motorized or non-motorized instrument or the like can be applied to rotate the drive member 63 and thus the implant 11. FIGS. 15 and 16 show a preassembly comprising an implant and an accompanying fixture mount assembly. The assembly includes the mount 70 and the retaining screw 71. The adapter includes a lobed configuration 73 substantially matching the lobed configuration 45 of the abutment (FIG. 9) so that when the mount 70 is inserted into the implant 11 in its assembled form as shown in FIG. 16, the lobed configuration 73 mates with and engages the lobed configuration 31 in driving relationship. A rotation member 74 is formed at the proximal end of the adapter 70 and may be a hexagonal shape as shown, a square, or any other shape that will accommodate a drive member. The mount 70 includes a central bore or throughhole 79 to receive the screw 71. The bore 79 includes an internally threaded portion 81 to capture the screw 71 within the adapter 70. The screw includes an externally threaded portion 75 at its distal end, an elongated shaft 76 and a head 78 with a slot 77 or other rotation means. When assembled with an implant 11, as shown in FIG. 16, the lobed portion 73 is inserted into the open end of the implant 11 to mate with the corresponding lobed portion 31 of the implant. The screw 71 is then inserted through the open end of the bore 79 and the distal end is threaded into the internal threads 32 of the implant 11. The screw 71 is tightened until the lower surface of the mount 78 tightly engages the proximal end 80 of the mount, thereby firmly securing the fixture mount assembly within the implant 11. Having described the structure of the dental implant and dental implant assembly of the present invention, its installation can be best understood as follows. First, after preparing the implant site within the patient's mouth, the implant is installed by rotating the same, either with a direct drive member 63 such as is shown in FIGS. 13 and 14 or with a preassembled fixture mount as shown in FIGS. 15 and 16. After the implant is installed to the desired installation depth, the drive member 63 or the fixture mount assembly is removed from the implant. The abutment is then positioned within the open end of the implant, with the lobed configuration 45 and surface 52 of the abutment being positioned within and engaging the lobed configuration 31 and surface 35 of the implant. The abutment screw 14 is then inserted into the open end of the bore 17 and rotated by a ratchet or other rotation tool known in the art. Rotation of the screw 14 forces the beveled surface 52 against the beveled surface 35 forming a tight friction fit. This provides stability between the abutment and the implant. Although the description of the preferred embodiment has been quite specific, it is contemplated that various modifications could be made without deviating from the spirit of the present invention. Accordingly, it is contemplated that the scope of the present invention be dictated by the appended claims rather than by the description of the preferred embodiment.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to the field of dental implants and more specifically to an internal connection implant. The invention also relates to the combination of an internal connection implant and a complementary abutment. 2. Description of the Prior Art A wide variety of dental implants currently exists in the art. Such dental implants commonly include a body with external threads for mounting and retaining the implant within the patient's mouth. Installation of the implant involves rotation of the implant into a predrilled or tapped site using a drive member such as a ratchet or other rotation means. The implant also includes a drive region which may be located externally or internally. Various structures for both externally and internally driving the implant currently exist. While many internally driven dental implants provide satisfactory torque transfer and stability between implant and abutment, implant connection failures continue to exist. Accordingly, there is a continuing need for an internal connection or internally driven implant which provides improved torque transfer and implant/abutment stability, with a structure that can also minimize implant connection failure.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention relates to a dental implant and combination dental implant and abutment assembly and more specifically to an internal connection dental implant and combined internal connection implant and abutment assembly. In general, the dental implant of the present invention includes a drive or indexing region which equalizes the stress distribution and provides for increased torque carrying capacity across the entire implant connection, thereby providing a drive means which minimizes implant connection failures and which is usable for all sizes of implants. The implant in accordance with the present invention also includes a stabilizing region which provides the implant and abutment with a highly stable connection. In the preferred embodiment, the drive and indexing region includes a plurality of equally dimensioned and equally configured concave and convex lobes which are positioned between a minor diameter and a major diameter. This lobed configuration provides increased surface area for contact with a wrench or other drive means during installation, as well as providing an outer implant wall of sufficient thickness to improve resistance to implant connection failures, particularly when accommodating off-axis loading. In the preferred embodiment, the stabilizing region for minimizing relative movement, so called micromotion, between the implant and a corresponding abutment, and thus improving stability between the implant and such abutment, includes a beveled surface positioned between the drive and indexing section and the proximal end of the implant. This beveled surface mates with a corresponding beveled surface of the abutment. The angle of this beveled surface is sufficient to form a friction fit so as to stabilize the interface between the implant and the abutment. Accordingly, it is an object of the present invention to provide an internal connection dental implant and assembly facilitating improved rotational or drive torque, while at the same time minimizing failures of the implant connection during installation and use. Another object of the present invention is to provide an internal connection dental implant and assembly which provides stability between the implant and the corresponding abutment. These and other objects of the present invention will become apparent with reference to the drawings, the description of the preferred embodiment and the appended claims.
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20040629
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20070731
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20051229
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91128.0
| 1
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WEHNER, CARY ELLEN
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INTERNAL CONNECTION DENTAL IMPLANT
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SMALL
| 0
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ACCEPTED
| 2,004
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10,879,837
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ACCEPTED
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System and method for protecting a computing device from computer exploits delivered over a networked environment in a secured communication
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A network security module for protecting computing devices connected to a communication network from identified security threats communicated in a secured communication is presented. The network security module is interposed, either logically or physically, between the protected computer and the communication network. Upon detecting a secured communication, the network security module obtains a decryption key from the computing device to decrypt the secured communication. The network security module then processes the decrypted communication according to whether the decrypted communication violates protective security measures implemented by the network security module.
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1. A network security module, interposed between a computing device and a network such that all network activities between the computing device and the network pass through the network security module, for protecting the computing device from an identified security threat on the network, the network security module comprising: a computing device connection connecting the network security module to the computing device; a network connection connecting the network security module to the network; a decoder module that temporarily decrypts a secured communication using an obtained decryption key; and a security enforcement module that controls network activities between the computing device and the network by implementing obtained security measures, thereby protecting the computing device from an identified security threat on the network. 2. The network security module of claim 1, wherein the security enforcement module controls network activities between the computing device and the network by obtaining the temporarily decrypted secured communication and evaluating the temporarily decrypted secured communication according to the obtained security measures. 3. The network security module of claim 1, wherein the decoder module obtains the decryption key to temporarily decrypt the secured communication from a decoding module on the computing device. 4. The network security module of claim 3 further comprising a secondary communication connection connecting the network security module to the computing device, and wherein the decoder module obtains the decryption key to temporarily decrypt the secured communication from a decoding module on the computing device over the secondary communication connection. 5. The network security module of claim 1, wherein the secured communication is encrypted according to the Secure Sockets Layer protocol. 6. The network security module of claim 1, wherein the secured communication is encrypted according to the Transport Layer Security protocol. 7. A method for protecting a computing device from an identified security threat delivered over a network, implemented on a network security module interposed between the computing device and the network such that all network activities between the computing device and the network pass through the network security module, the method comprising: obtaining protective security measures for protecting the computing device from an identified security threat; detecting a secured communication directed to the computing device; temporarily decrypting the secured communication; and implementing the protective security measures on the temporarily decrypted secured communication. 8. The method of claim 7 further comprising obtaining a decryption key from the computing device for decrypting the secured communication. 9. The method of claim 8, wherein the decryption key is obtained from the computing device over a secondary communication connection between the network security module and the computing device. 10. The method of claim 9, wherein the decryption key is obtained from a decoding module on the computing device. 11. The method of claim 9, wherein the secured communication is encrypted according to the Secure Sockets Layer protocol. 12. The method of claim 9, wherein the secured communication is encrypted according to the Transport Layer Security protocol. 13. The method of claim 7 further comprising obtaining configuration information regarding the computing device from the computing device, and wherein obtaining protective security measures for protecting the computing device from an identified security threat comprises obtaining protective security measures for protecting the computing device according to the configuration information regarding the computing device. 14. A network security module, interposed between a network device and a network such that all network activities between the network device and the network pass through the network security module, for protecting the network device from an identified security threat on the network, the network security module comprising: a network device connection connecting the network security module to the network device; a network connection connecting the network security module to the network; a decoder means that temporarily decrypts a secured communication using an obtained decryption key; and a security enforcement means that controls network activities between the network device and the network by implementing obtained security measures, thereby protecting the network device from an identified security threat on the network. 15. The network security module of claim 14, wherein the security enforcement means controls network activities between the network device and the network by obtaining the temporarily decrypted secured communication from the decoder means and evaluating the temporarily decrypted secured communication according to the obtained security measures. 16. The network security module of claim 14, wherein the decoder means obtains the decryption key to temporarily decrypt the secured communication from a decoding module on the network device. 17. The network security module of claim 16 further comprising a secondary communication connection connecting the network security module to the network device, and wherein the decoder means obtains the decryption key to temporarily decrypt the secured communication from a decoding means on the network device over the secondary communication connection. 18. The network security module of claim 14, wherein the secured communication is encrypted according to the Secure Sockets Layer protocol. 19. The network security module of claim 14, wherein the secured communication is encrypted according to the Transport Layer Security protocol.
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CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No. 60/544,772, filed Feb. 13, 2004. FIELD OF THE INVENTION The present invention relates to a system and method for protecting a computing device from computer exploits delivered over a networked environment in a secured communication. BACKGROUND OF THE INVENTION As more and more computers, and other computing devices, are inter-connected through various networks, such as the Internet, computer security has become increasingly more important, particularly from invasions or attacks delivered over a network or over an information stream. As those skilled in the art will recognize, these attacks come in many different forms, including, but certainly not limited to, computer viruses, computer worms, system component replacements, denial of service attacks, even misuse/abuse of legitimate computer system features, all of which exploit one or more computer system vulnerabilities for illegitimate purposes. While those skilled in the art will realize that the various computer attacks are technically distinct from one another, for purposes of the present invention and for simplicity in description, all of these attacks will be generally referred to hereafter as computer exploits, or more simply, exploits. When a computer system is attacked or “infected” by a computer exploit, the adverse results are varied, including disabling system devices; erasing or corrupting firmware, applications, or data files; transmitting potentially sensitive data to another location on the network; shutting down the computer system; or causing the computer system to crash. Yet another pernicious aspect of many, though not all, computer exploits is that an infected computer system is used to infect other computers. FIG. 1 is a pictorial diagram illustrating an exemplary networked environment 100 over which a computer exploit is commonly distributed. As shown in FIG. 1, the typical exemplary networked environment 100 includes a plurality of computers 102-108 all inter-connected via a communication network 110, such as an intranet or via a larger communication network including the global TCP/IP network commonly referred to as the Internet. For whatever reason, a malicious party on a computer connected to the network 110, such as computer 102, develops a computer exploit 112 and releases it on the network. The released computer exploit 112 is received by, and infects, one or more computers, such as computer 104, as indicated by arrow 114. As is typical with many computer exploits, once infected, computer 104 is used to infect other computers, such as computer 106 as indicated by arrow 116, which in turn infects yet other computers, such as computer 108 as indicated by arrow 118. Clearly, due to the speed and reach of the modern computer networks, a computer exploit 112 can “grow” at an exponential rate, and quickly become a local epidemic that quickly escalates into a global computer pandemic. A traditional defense against computer exploits, and particularly computer viruses and worms, is anti-virus software. Generally, anti-virus software scans incoming data, arriving over a network, looking for identifiable patterns associated with known computer exploits. Upon detecting a pattern associated with a known computer exploit, the anti-virus software may respond by removing the computer virus from the infected data, quarantining the data, or deleting the “infected” incoming data. Unfortunately, anti-virus software typically works with “known,” identifiable computer exploits. Frequently, this is done by matching patterns within the data to what is referred to as a “signature” of the exploit. One of the core deficiencies in this exploit detection model is that an unknown computer exploit may propagate unchecked in a network until a computer's anti-virus software is updated to identify and respond to the new computer exploit. As anti-virus software has become more sophisticated and efficient at recognizing thousands of known computer exploits, so too have the computer exploits become more sophisticated. For example, many recent computer exploits are now polymorphic, or in other words, have no identifiable pattern or “signature” by which they can be recognized by anti-virus software in transit. These polymorphic exploits are frequently unrecognizable by anti-virus software because they modify themselves before propagating to another computer system. Another defense that is common today in protecting against computer exploits is a hardware or software network firewall. As those skilled in the art will recognize, a firewall is a security system that protects an internal network from unauthorized access originating from external networks by controlling the flow of information between the internal network and the external networks. All communications originating outside of the firewall are first sent to a proxy that examines the communication, and determines whether it is safe or permissible to forward the communication to the intended target. Unfortunately, properly configuring a firewall so that permissible network activities are uninhibited and that impermissible network activities are denied is a sophisticated and complicated task. In addition to being technically complex, a firewall configuration is difficult to manage. When firewalls are improperly configured, permissible network traffic may be inadvertently shut down and impermissible network traffic may be allowed through, compromising the internal network. For this reason, changes to firewalls are generally made infrequently, and only by those well versed in the subject of technical network design. As yet a further limitation of firewalls, while a firewall protects an internal network, it does not provide any protection for specific computers. In other words, a firewall does not adapt itself to a specific computer's needs. Instead, even if a firewall is used to protect a single computer, it still protects that computer according to the firewall's configuration, not according to the single computer's configuration. Yet another issue related to firewalls is that they do not provide protection from computer exploits originating within the borders established by a firewall. In other words, once an exploit is able to penetrate the network protected by a firewall, the exploit is uninhibited by the firewall. This situation frequently arises when an employee takes a portable computer home (i.e., outside of the corporate firewall protection) and uses it at home in a less secured environment. Unknown to the employee, the portable computer is then infected. When the portable computer is reconnected to the corporate network within the protection of the firewall, the exploit is often free to infect other computers unchecked by the firewall. As mentioned above, computer exploits now also leverage legitimate computer system features in an attack. Thus, many parties other than firewall and anti-virus software providers must now join in defending computers from these computer exploits. For example, operating system providers must now, for economic and contractual reasons, continually analyze their operating system functions to identify weaknesses or vulnerabilities that may be used by a computer exploit. For purposes of the present discussion, any avenue by which a computer exploit may attack a computer system will be generally referred to as a computer system vulnerability, or simply a vulnerability. As vulnerabilities are identified and addressed in an operating system, or other computer system components, drivers, applications, the provider will typically release a software update to remedy the vulnerability. These updates, frequently referred to as patches, should be installed on a computer system in order to secure the computer system from the identified vulnerabilities. However, these updates are, in essence, code changes to components of the operating system, device drivers, or software applications. As such, they cannot be released as rapidly and freely as anti-virus updates from anti-virus software providers. Because these updates are code changes, the software updates require substantial in-house testing prior to being released to the public. Unfortunately, even with in-house testing, a software update may cause one or more other computer system features to break or malfunction. Thus, software updates create a huge dilemma to parties that rely upon the computer systems. More specifically, does a party update their computer systems to protect them from the vulnerability and risk disrupting their computer systems' operations, or does the party refrain from updating their computer systems and run the risk that their computer systems may be infected? Under the present system, there is a period of time, referred to hereafter as a vulnerability window, that exists between when a new computer exploit is released on the network 110 and when a computer system is updated to protect it from the computer exploit. As the name suggests, it is during this vulnerability window that a computer system is vulnerable, or exposed, to the new computer exploit. FIGS. 2A-2B are block diagrams of exemplary timelines illustrating this vulnerability window. In regard to the following discussions regarding timelines, significant times or events will be identified and referred to as events in regard to a timeline. FIG. 2A illustrates a vulnerability window of computer systems with regard to one of the more recent, sophisticated class of computer exploits that are now being released on public networks. As will be described below, this new class of computer exploits take advantage of a system provider's proactive security measures to identify computer system vulnerabilities, and subsequently, create and deliver a computer exploit. With reference to FIG. 2A, at event 202, an operating system provider identifies the presence of a vulnerability in the released operating system. For example, in one scenario, the operating system provider, performing its own internal analysis of a released operating system, uncovers a previously unknown vulnerability that could be used to attack a computer system. In an alternative scenario, the previously unknown vulnerability is discovered by third parties, including organizations that perform system security analyses on computer systems, and relays information regarding the vulnerability to the operating system provider. Once the operating system provider is aware of the presence of the security vulnerability, the operating system provider addresses the vulnerability which, at event 204, leads to the creation and release of a patch to secure any computer systems running the operating system. Typically, an operating system provider will make some type of announcement that there is a system patch available, along with a recommendation to all operating system users to install the patch. The patch is usually placed in a known location on the network 110 for downloading and installation onto affected computer systems. Unfortunately, as happens all too often, after the operating system provider releases the patch, at event 206, a malicious party downloads the patch and, using some reverse engineering as well as any information made public by the operating system or others, identifies the specifics regarding the “fixed” vulnerability in the operating system. Using this information, the malicious party creates a computer exploit to attack the underlying vulnerability. At event 208, the malicious party releases the computer exploit onto the network 110. While the goal of issuing a software patch, also known as a “fix,” is to correct an underlying vulnerability, the “fix” is often a complex piece of software code which itself, unfortunately, may create or contain a new vulnerability that could be attacked by a computer exploit created by a malicious party. Thus, in addition to evaluating what the “fix” corrects, the “fix” is also evaluated for potential vulnerabilities. While a “fix” is available, the malicious party realizes that, for various reasons including those described above, not every vulnerable computer system will be immediately upgraded. Thus, at event 208, the malicious party releases the computer exploit 112 onto the network 110. The release of the computer exploit 112 opens a vulnerability window 212, as described above, in which the vulnerable computer systems are susceptible to this computer exploit. Only when the patch is finally installed on a computer system, at event 210, is the vulnerability window 212 closed for that computer system. While many computer exploits released today are based on known vulnerabilities, such as in the scenario described in regard to FIG. 2A, occasionally, a computer exploit is released on the network 110 that takes advantage of a previously unknown vulnerability. FIG. 2B illustrates a vulnerability window 230 with regard to a timeline 220 under this scenario. Thus, as shown on timeline 220, at event 222, a malicious party releases a new computer exploit. As this is a new computer exploit, there is neither an operating system patch nor an anti-virus update available to protect vulnerable computer systems from the attack. Correspondingly, the vulnerability window 230 is opened. At some point after the new computer exploit is circulating on the network 110, the operating system provider and/or the anti-virus software provider detects the new computer exploit, as indicated by event 224. As those skilled in the art will appreciate, typically, the presence of the new computer exploit is detected within a matter of hours by both the operating system provider and the anti-virus software provider. Once the computer exploit is detected, the anti-virus software provider can begin its process to identify a pattern, or “signature,” by which the anti-virus software may recognize the computer exploit. Similarly, the operating system provider begins its process to analyze the computer exploit to determine whether the operating system must be patched to protect it from the computer exploit. As a result of these parallel efforts, at event 226, the operating system provider and/or the anti-virus software provider releases an update, i.e., a software patch to the operating system or an anti-virus update, which addresses the computer exploit. Subsequently, at event 228, the update is installed on a user's computer system, thereby protecting the computer system and bringing the vulnerability window 230 to a close. As can be seen from the examples above, which are only representative of all of the possible scenarios in which computer exploits pose security threats to a computer system, a vulnerability window exists between the times that a computer exploit 112 is released on a network 110, and when a corresponding update is installed on a user's computer system to close the vulnerability window. Sadly, whether the vulnerability window is large or small, an infected computer costs the computer's owner substantial amounts of money to “disinfect” and repair, if it is at all possible. This cost can be enormous when dealing with large corporations or entities that may have thousands or hundreds of thousands of devices attached to a network 110. Such a cost is further amplified by the possibility that such an exploit tamper or destroys customer data, all of which may be extremely difficult or impossible to trace and remedy. What is needed is a system and method for securing a computer system against computer exploits in a responsive manner and according to the individual computer system's needs, even before a protective update is available and/or installed on the computer system. These, and other issues found in the prior art, are addressed by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a pictorial diagram illustrating an exemplary network environment, as found in the prior art, over which a computer exploit is commonly distributed; FIGS. 2A and 2B are block diagrams illustrating exemplary timelines demonstrating different vulnerability windows of computer systems with regard to computer exploits released on a network; FIGS. 3A and 3B are pictorial diagrams illustrating exemplary networked environments suitable for implementing aspects of the present invention; FIGS. 4A and 4B are pictorial diagrams of exemplary timelines for demonstrating how the present invention minimizes the vulnerability window associated with computer exploits; FIG. 5 is a flow diagram of an exemplary routine for dynamically controlling a computer system's network access according to published security information, in accordance with the present invention; FIG. 6 is a flow diagram illustrating an exemplary routine implemented by a security service for publishing the security information for network security modules in the exemplary networked environment, in accordance with the present invention; FIG. 7 is a flow diagram illustrating an exemplary routine implemented by a security service to receive and respond to a request for security information from a network security module; FIG. 8 is a flow diagram illustrating an exemplary method implemented by a network security module, for controlling the flow of network traffic between a computer and the network according to security measures obtained from the security service; FIG. 9 is a pictorial diagram illustrating an exemplary network security module implemented as a hardware device external to the computer; FIG. 10 is a block diagram illustrating logical components of a network security module, formed in accordance with the present invention; FIG. 11 is a block diagram illustrating how computer exploits may be delivered to a computing device using secured communications; FIG. 12 is a block diagram illustrating how a network security module, adapted according to aspects of the present invention, is able to protect a computing device from a computer exploit delivered to the computing device using secured communications; and FIGS. 13A and 13B illustrate a block diagram of an exemplary routine for detecting secured communications and processing secured communications in accordance with aspects of the present invention. SUMMARY OF THE INVENTION In accordance with aspects of the present invention, a network security module interposed between a computing device and a network, for protecting the computing device from an identified security threat over the network is presented. The network security module is positioned such that all network activities between the computing device and the network pass through the network security module. The network security module includes a computing device connection. The computing device connection connects the network security module to the computing device. The network security module also includes a network connection that connects the network security module to the network. It is through the computing device connection and network connection that network activities pass through the network security module. The network security module also includes a decoder module. The decoder module temporarily decrypts secured communications using an obtained decryption key. The network security module further includes a security enforcement module that controls the network activities between the computing device and the network. The security enforcement module implements obtained security measures, thereby protecting the computing device from an identified security threat on the network. In accordance with further aspects of the present invention, a method, implemented on a network security module interposed between a computing device and a network such that all network activities between the computing device and the network must pass through the network security module, for protecting the computing device from an identified security threat, is presented. Protective security measures are obtained. The protective security measures, when enforced, protect the computing device from an identified security threat. A secured communication directed to the computing device is detected. The secured communication is then temporarily decrypted. Thereafter, the protective security measures are implemented on the temporarily decrypted secure communication. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 3A is a pictorial diagram illustrating an exemplary networked environment 300 suitable for implementing aspects of the present invention. The exemplary networked environment 300 includes a computer 302 connected to a network 110. It should be noted that while the present invention is generally described in terms of operating in conjunction with a personal computer, such as computer 302, it is for illustration purposes only, and should not be construed as limiting upon the present invention. Those skilled in the art will readily recognize that almost any networked computing device may be attacked by a computer exploit. Accordingly, the present invention may be advantageously implemented to protect numerous types of computers, computing devices, or computing systems including, but not limited to, personal computers, tablet computers, notebook computers, personal digital assistants (PDAs), mini- and mainframe computers, wireless phones (frequently referred to as cell phones), hybrid computing devices such as wireless phone/PDA combinations, and the like. The present invention may also be advantageously implemented to protect hardware devices, peripheral devices, software applications, device drivers, operating systems, and the like. It should be appreciated that the network 110 may include any number of actual communication networks. These actual communication networks include, but are not limited to, the Internet, wide and local area networks, intranets, cellular networks, IEEE 802.11 and Bluetooth wireless networks, and the like. Accordingly, while the present invention is discussed in terms of a computer network, and in particular the Internet, it is for illustration purposes only, and should not be construed as limiting upon the present invention. The exemplary networked environment 300 also includes a network security module 304 and a security service 306. The network security module 304 is interposed between a computer, such as computer 302, and the network 110. The network security module 304 may be interposed between the computer 302 and the network 110 either physically or logically. Communications between the computer 302 and the network 110 flow through the network security module 304. According to the present invention, the network security module 304 selectively controls the network activities between the computer 302 and the network 110 according to security information corresponding to the computer's specific configuration, including, but not limited to, the particular operating system revision installed on the computer 302, anti-virus information, including revision information for both the anti-virus software and corresponding signature data files, installed applications, device drivers, and the like, all of which may be a potential target of a computer exploit to take advantage of a computer system vulnerability. According to one embodiment of the present invention, in order to periodically obtain security information from the security service 306, the network security module 304 periodically issues a security information request to the security service 306 for security information corresponding to the particular, specific configuration of the computer 302. The network security module 304 may be configured to periodically obtain the security information from the security service 306. For example, the network security module 304 may be configured to obtain security information from the security service 306 every minute. Alternatively, the network security module 304 may be configured to obtain security information from the security service 306 according to a user specified period of time. Obtaining security information corresponding to a computer's particular, specific configuration is important as many users must delay updating their computer systems for a myriad of reasons. For example, a delay in updating an operating system or anti-virus software may occur because a computer has been inactive for a while. Thus, while the most recent revision of operating system and/or anti-virus software may provide adequate protection from a newly discovered computer exploit, a computer may not be “up to date”, and thus, susceptible to the computer exploit and must implement security measures that corresponds with the computer's particular configuration. Accordingly, the security information request may include, but is not limited to, information identifying the computer's operating system revision, including installed patches; the particular anti-virus software and revision used by the computer, as well as software and data file updates; and network-enabled application information, such as e-mail or browser identifiers, revisions, firmware providers and versions, and other security settings. According to aspects of the present invention, the network security module 304 obtains the computer's particular configuration information as one of the acts of updating a computer system component. For example, when a user installs an operating system patch on the computer 302, as one of the acts of installing the operating system patch, the network security module 304 is notified of the now current revision of the operating system. Similarly, other computer system features, such as a network-enabled application or anti-virus software, notify the network security module 304 as they are updated, all so that the network security module may obtain the most accurate and sufficient security information to protect the computer 302 according to the computer's specific current configuration. Based on the computer's particular configuration information in the security information request, the security service 306 identifies relevant security information to protect the computer from known or perceived computer system vulnerabilities. Identifying relevant security information is described in greater detail below. The security information includes protective security measures, to be implemented by the network security module 304, that enable the network security module to insulate the computer 302 from computer exploits of known vulnerabilities. Protective security measures may include any number of network activity controls, or combinations thereof, including, but not limited to: blocking all network activities between the computer 302 and the network 110, except communications between certain known, secure network locations, such as the security service 306 or the anti-virus software service 308 for installing patches or updates; blocking network traffic on specific communication ports and addresses; blocking communications to and/or from certain network-related applications, such as an e-mail or Web browser application; and blocking access to particular hardware or software components on the computer 302. Thus, upon receiving the security response, the network security module implements the security measures. As mentioned above, the network security module 304 is interposed between the computer 302 and the network 110 and, as such, all network activities between the computer and the network must flow through the network security module. As network traffic flows through the network security module 304, the network security module monitors the network traffic and implements the protective security measures received from the security service 306, such as blocking all network access except communications between known, secure locations, and the like. According to further aspects of the present invention, a security response may also include a designated security level, such as levels red, yellow, and green. The security levels represent information that identifies, to the computer's 302 user, a representative level of protective measures implemented by the network security module 304. For example, a security level of red may indicate that the network security module 304 is currently blocking all network activities between the computer 302 and the network 110 except access to and from known, secure locations. Alternatively, a security level of yellow may indicate that the network security module 304 is currently implementing some protective security measures, yet the computer 302 may still otherwise communicate with the network 110. Still further, a security level of green may indicate that the network security module 304 is not implementing any protective security measures, and communications between the computer 302 and the network 110 are unrestricted. In accordance with the above described security levels, and for description purposes, a security level of red may also be referred to as full lock-down, a security level of yellow may also be referred to as partial lock-down, and a security level of green may also be referred to as free network access. While the above description identifies three security levels and a schema of red, yellow, and green, they are illustrative, and should not be construed as limiting upon the present invention. Those skilled in the art will readily recognize that any number of security levels may be implemented with alternative schemas for their representation to a user. As the network security module 304 operates in an autonomic manner, i.e., requiring no user intervention, the above-identified security levels, as well as any corresponding visual representations of the security levels, are for user information purposes only. They may be used to provide the user with an indication of the level of restrictions that are implemented by the network security module 304. This visual indication may be especially useful when a user is trying to determine whether a network connection is malfunctioning, or that network activity is restricted due to current network security concerns. According to aspects of the present invention and as an added measure of security, when the network security module 304 is powered up, the network security module enters a default state. This default state corresponds to the highest level of security, i.e., full lock-down, such that network activities between the computer 302 and trusted network locations are permissible. Either as part of the power up, or as part of the periodic communication with the security service 306, the network security module 304 obtains up-to-date security information and, depending on that security information, may impose less restrictive security measures. Clearly, implementing a default state of full lock-down at the network security module 304 is beneficial to the computer 302 as a vulnerability could have been identified, or an exploit released on the network 110 during the time that the network security module was powered off. In accordance with one embodiment of the present invention, the network security module 304 does not request or access information from the computer 302. Instead, the network security module 304 operates on information transmitted to it from the computer 302 in connection with certain events. Thus, when a network security module 304 first commences to protect a computer, such as when a network security module is first interposed between a computer 302 and the network 110, the network security module will not have any specific configuration information corresponding to the computer system. As mentioned above, when the network security module 304 has no configuration information regarding the computer 302, or when the network security module 304 is powered up, the network security module enters its default state, i.e., full lock-down. However, as mentioned above, full lock-down will still permit the computer 302 to communicate with known, secure locations. As an example, these known, secure locations include the location, or locations, where operating system updates are located. Thus, a user may run an update process that results in configuration information being sent to the network security module 304, even when the computer 302 is configured with the latest operating system, anti-virus software, application, and device driver revisions and updates that are available. Alternatively, a specific program may be provided that notifies the network security module 304 of the computer system's current configuration. In order to ensure that communications between the network security module 304 and the security service 306 are authentic and uncorrupted, in one embodiment of the present invention, communications between the network security module and the security service, such as security requests and security information, are delivered in encrypted, secured communications, such as secured communications using the Secure Sockets Layer (SSL) protocol. Similarly, communications between the network security module 304 and the computer 302 are also similarly secured. According to optional aspects of the present invention, the network security module 304 continues to operate, i.e., obtain security information corresponding to the computer 302, even when the computer is powered off. For example, the network security module 304 may continue to obtain security information for the computer 302, all according to the latest operating system and/or anti-virus software revision data provided the computer when in was powered on. According to one embodiment, the network security module 304 is connected to the auxiliary power rail of a computer that, as is known to those skilled in the art, provides power to peripheral devices even when the computer 302 is powered off. Additionally, if the network security module 304 operates only when the computer 302 is operating, when the network security module resumes operation, the network security module implements a full lock-down while it obtains the most recent security information corresponding to the computer's current configuration. According to another embodiment of the present invention, the network security module 304 may be optionally disabled by a user. This is useful as there are certain times that the necessity of full access to a network outweighs the risk of an attack from a computer exploit. For example, it may be necessary to disable the network security module 304 when attempting to diagnose networking problems/issues. Alternatively, some emergency situations, such as using the E911 voice over IP (VoIP) service may necessitate that the network security module 304 be disabled. According to one aspect of the invention, when disabled, the network security module 304 continues to obtain security information from the security service 306, though it does not implement the protective security measures. Continually updating the security information is beneficial to the user, especially if the network security module 304 is only temporarily disabled, as the network security module will have the most recent security information when re-enabled. Alternatively, if the network security module 304 is disabled and not continually updating, after a predetermined period of no communication with the security service 306, the network security module may revert to its default condition, i.e., a full lock-down of network activity. The security service 306 may be implemented as a single server/source for all security information, or alternatively, as a hierarchy of servers/sources distributed throughout the network 110. In a hierarchical system, a network security module 304 is initially configured with a root server/service in security service, one that will always be present. However, as part of the security information returned by the security service, perhaps in the first communication between the network security module 304 and the security service, the security service provides information regarding the hierarchy of the security service. This information may be provided as one or more ranges of network addresses, all of which are nodes in the security service hierarchy and that are able to provide the network security module 304 the appropriate security information. Thereafter, the network security module 304 need not necessarily query the original node to obtain information. Obviously, one advantage of implementing the security service in a hierarchical manner is that the security service may be easily scaled up or down in order to accommodate the number of network security module requesting information, and the original node in the security service hierarchy will not be overwhelmed by security information requests from all network security modules in a network. Under a hierarchical structure distributed in the network 110, load balancing may also occur and redundancy may be built into the system such that if one node in the hierarchy fails, others may step in and provide the security information. According to aspects of the present invention, the network security module 304 is transparent to the computer 302 and to the network 110, using a technique known in the art as port mimicking. Generally speaking, using port mimicking, the network security module 304 appears as the network 110 to the computer 302, and appears as the computer to devices on the network. Thus, network activity freely flows between the computer 302 and the network 110 through the network security module 304, unless the network security module determines that the communication is directed to the network security module, such as notification of an operating system update or a security information response, or unless the network security module must block the network activity according to the protective security measures. As described above, the network security module 304 obtains security information from the security service 306 as a result of a query. Those skilled in the art will recognize this as a poll system, i.e., polling the security service 306 for the security information. However, in an alternative embodiment, the security service 306 advantageously broadcasts important security information to the network security modules in the network 110. For example, depending on the periodic intervals at which the network security modules in the networked environment 300 obtain security information from the security service 306, if a particularly virulent computer exploit begins to circulate the network 110, rather than wait for network security modules to request important security information, the security service broadcasts security information to the network security modules. This security information, referred to hereafter as a security bulletin, will typically include all configurations that are susceptible to the computer exploit, protective security measures to be taken, as well as indicating the corresponding security level. According to one embodiment of the present invention, the security bulletins are XML documents, organized according to a predetermined schema. A system that broadcasts information to listeners is referred to as a push system, i.e., the security service 306 pushes important security information to the network security modules. According to aspects of the present invention, security bulletins are broadcast over the network 110 using a “guaranteed delivery” service. In a guaranteed delivery service, security bulletins are identified as high priority items, and in agreement with the network service providers, are delivered before the delivery of other network traffic that would otherwise be delivered first. In addition to delivering the security bulletins over the same network 110 upon which the computer 302 communicates, there are many times that it would be advantageous to communicate “out of band,” i.e., over a second communication link separate from the network 110. FIG. 3B is a pictorial diagram illustrating an alternatively configured networked environment 310 for implementing aspects of the present invention, including a second communication link 314 for delivering security information to the network security modules attached to the network 110. As shown in FIG. 3B, the alternatively configured networked environment 310 includes similar components as those described above in regard to the networked environment 300, including the computer 302, the security service 306, and the network security module 304. However, the security service 306 is additionally configured to transmit security information, including both security information and/or security bulletins, to a network security module 304 specifically adapted with a receiving device 312 to receive the information over the second communication link 314. According to aspects of the present invention, the second communication link 314 may be a satellite communication link, a radio frequency broadcast, or some other form of secondary communication between the security service 306 and the network security module 304. Those skilled in the art will appreciate that any number of communication channels may be used. According to alternative aspects of the invention, the second communication link 314 may be a one-way communication link from the security service 306 and the network security module 304, or a two-way communication link for communications between the security service and the security module. Additionally, software updates or patches, as mentioned above, may also be available for download over the second communication link 314 from the security service 306. While the network security module 304 is interposed between the computer 302 and the Internet 110, actual embodiments of a network security module may vary. In each case, the network security module 304 is treated as a trusted component by the computer 302. According to one embodiment, the network security module 304 is implemented as a hardware device, sometimes called a “dongle,” external to the computer 302, with connections to the network 110 and to the computer. Alternatively, the network security module 304 may be implemented as a hardware component integrated within the computer 302, or as an integrated sub-component within the computer's network interface. Integrating the network security module 304 within the computer 302 or as a sub-component on the computer's network interface may be especially useful when the computer 302 is connected to the network 110 via a wireless connection. According to another alternative embodiment, the network security module may be implemented as logic, such as microcoding or firmware, within a component of the computer 302, including, but not limited to, the processor, graphics processing unit, north bridge, or south bridge. As yet a further alternative embodiment, the network security module 304 may be implemented as a software module operating in conjunction with, or as part of, the operating system, or as a separate application installed on the computer 302. The software implemented network security module 304 may operate on a second processor in the computer 302. The second processor may or may not be implementing other computer system tasks asymmetrically with the computer's main processor. Accordingly, the network security module 304 should not be construed as limited to any particular embodiment. It should be pointed out that one of the benefits realized by the present invention is that the system mitigates the effects of many exploits. For example, those skilled in the art will recognize that a denial of service (DOS) attack is an attempt to overwhelm a computer with network requests, to the end that the computer exhausts its resources and crashes, or alternatively, erroneously enters an ambiguous state that is more vulnerable to external attacks/exploits. However, with a network security module 304 responding to a security service 306 by implementing protective security measures, such exploits, including the potentially overwhelming network requests, never reach the computer 302. In order to more fully understand how the above-described components operate to provide enhanced security to the computer 302, reference is made to exemplary scenarios, illustrated on timelines with corresponding events. FIGS. 4A and 4B are block diagrams illustrating exemplary timelines for demonstrating the operation of the components of the present invention. More particularly, FIG. 4A is a block diagram illustrating an exemplary timeline 400 for demonstrating how the present invention minimizes the vulnerability window 406 of a computer 302 with regard to the release of a new computer exploit on the network 110. It should be noted that while the following is presented as a computer exploit attacking an operating system, it is for illustration purposes, and should not be construed as limiting upon the present invention. The present invention may be utilized to protect code modules, services, even hardware devices on a computer system. As shown on the timeline 400, at event 402, a malicious party releases a new computer exploit onto the network 110. The release of the new computer exploit commences the vulnerability window 406 for computers connected to the network 110 targeted by the new computer exploit, such as computer 302. At event 404, the presence of the new computer exploit is detected, either by the operating system provider, the anti-virus provider, or others, as described above. Upon detecting the presence of the new computer exploit, even before the nature or mode of attack of the exploit is identified, at event 408, the operating system provider, publishes security information via the security service 306. Typically, when a computer exploit is discovered, and its nature, extent, or mode of attack is not well known, the security service will set the security level for all apparently affected computer systems at red, i.e., full lock-down. At block 410, the network security module 304 obtains the security information, either in its periodic request or as a security bulletin, and implements the corresponding security measures, in this case, full lock-down. Beneficially, upon implementing the security measures from the security service 306, the vulnerability window 406 of targeted computers is closed. In contrast to the vulnerability window 230 of FIG. 2B, vulnerability window 406 is relatively small, thereby minimizing the exposure of targeted computer systems to the new computer exploit. Clearly, the actual length of time that a vulnerability window is open, such as vulnerability window 406, depends upon a small number of factors. One factor is the amount of time that passes before the computer exploit is detected. As discussed above, a new computer exploit is typically detected within fifteen minutes to a few hours from release. A second factor, much more variable than the first, is the amount of time it takes for the network security module 304 to obtain security information from the security service 306. Assuming that the network security module 304 may continually obtain security information, it may take mere seconds to obtain the security information and implement the corresponding security measures. However, if the network security module 304 cannot continually communicate with the security service 306, or if the periodic time frame for obtaining the security information is long, implementing the protective security measures may take a very long time. According to aspects of the present invention, if the network security module 304 is out of contact with the security service 306 for a predetermined amount of time, the network security module defaults to a full lock-down status, pending future communication from the security service. After the initial security information is published, the operating system provider or anti-virus software provider will typically continue analyzing the computer exploit in order to better understand how it operates, and/or what specific computer system features it attacks. From this analysis, a second, perhaps less restrictive, set of protective measures is identified that vulnerable computer systems must take to prevent the computer exploit from infecting them. Accordingly, at event 412, updated security information is published with a security level of yellow and identifying protective measures to block at-risk network activities, i.e., partial lock-down. For example, as described above, the protective security measures may include simply blocking access to and from a specific range of communication ports, including the source and/or destination ports, or disabling e-mail communications, Web access, or other network activities directed to the operating system, applications, device drivers, and the like, installed on a protected computer system, while permitting other network activities to flow freely. It should be understood that “at-risk” network activities include network activities that represent a threat to a computing system by an exploit, whether or not the exploit attacks computer system flaws or simply abuses legitimate computer system features. Additionally, the “at-risk” network activities include network activities directed to a computer system that are unilaterally initiated by another device. In other words, “at-risk” network activities includes the network activities of exploits directed at a computer system that has done nothing more that connect to the network. At event 414, the updated security information is obtained by the network security module 304, and the corresponding protective security measures are implemented. At event 416, after the operating system provider and/or anti-virus provider has generated and made available a software update, additional updated security information is published. This additional updated security information may identify that the security level is green, provided that a software update, such as an update from the operating system provider, the anti-virus software provider, or application provider, is installed on the computer 302. Subsequently, at event 418, the additional updated security information is obtained, the software updates are installed on the computer 302, and the network security module 304 enables free, i.e., unrestricted, network access. FIG. 4B is a block diagram illustrating an alternative exemplary timeline 420 for demonstrating how the present invention eliminates the vulnerability window that may exist with regard to the release of a computer exploit on the network 110, more particularly, an exploit that takes advantage of a previously identified vulnerability rather than an entirely new attack. As mentioned, the use of a previously known vulnerability is much more commonplace than entirely new attacks. At event 422, the operating system provider identifies the presence of a vulnerability in the current release of the operating system. In response to the threat posed by the identified vulnerability, at event 424, the operating system provider publishes mitigating security information, setting the security level and identifying corresponding protective security measures. In the present example shown in FIG. 4B, assuming that the vulnerability poses a substantial risk to the computers connected to the network 110, the operating system provider publishes security information setting the security level to red with security measures to implement a full lock-down. At event 426, the network security module 304 obtains the latest security information and implements the full lock-down. It should be noted that security measures are implemented that protect the computer 302 from the identified vulnerability before a patch or “fix” is available. As the majority of computer exploits are somehow derived from information gained by analyzing the vulnerabilities that a patch corrects, a malicious party is proactively denied the opportunity to create an exploit to attack the vulnerability. Thus, no vulnerability window is opened. Obviously, this result is a substantial benefit to the computer user, especially in contrast to the corresponding time line 200 illustrated in FIG. 2A when the network security module is not implementing the security measures. Frequently, after further analysis of the computer exploit, an operating system provider may determine a less restrictive set of protective measures that will protect the computers connected to the network from the computer exploit. Thus, as shown in FIG. 4B, at event 428, an updated security bulletin is published, setting the security level at yellow and including corresponding protective security measures, i.e., partial lock-down, that specifically address the exploited vulnerability, while enabling all other network activities. Correspondingly, at event 430, the updated security information is obtained and the network security module 304 implements the partial lock-down. Once an operating system patch or anti-virus update is available which, if installed on a computer 302, would protect it from a computer exploit targeting the vulnerability, at event 432, the operating system provider publishes the information, and indicates that once installed, the network security modules may permit free network access, i.e., setting the security level to green once the patch is installed. Correspondingly, at event 434, after the patch or anti-virus update is installed on the computer 302, the network security module 304 enables free access. FIG. 5 is a flow diagram illustrating an exemplary routine 500 for dynamically controlling a computer's network access according to published security information. FIG. 5 includes two starting terminals, starting terminal 502 corresponding to the startup of a network security module 304, and starting terminal 520 corresponding to receiving an update notice from the computer system 302. Beginning first at starting terminal 502 and proceeding to block 504, the network security module 304 implements full lock-down related security measures. As described above, when in full lock-down, the computer is limited to accessing known, trusted network locations, including the security service 306, in order to obtain the latest security status information and any available updates. At block 506, the network security module 304 obtains the latest security information from the security service 306 corresponding to the computer's current configuration. According to aspects of the present invention, the network security module 304 may obtain the latest security information from the security service by issuing a request to the security service for that information. Alternatively, the network security module 304 may obtain the latest security information as a broadcast from the security service 306, either over a second communication link or as a broadcast over the network. At decision block 508, based on the latest security information obtained from the security service 306, the network security module 304 determines whether the currently implemented security measures, and corresponding security level, are up to date with the obtained security information. According to one aspect of the present invention, this determination is made as a simple comparison of revision information for the computer system that the network security module currently has stored against what the security service publishes as the latest revisions. If the currently implemented security measures are not up to date, at block 510, the network security module 304 obtains security measures for the computer system according to information that the network security module has stored regarding the computer system. Alternatively (not shown), the security measures may be included with the obtained security information. Once the network security module 304 has the security measures, at block 512, the network security module implements the security measures and sets the corresponding security level, e.g., red, yellow, or green. After implementing the security measures for the computer system, or alternatively, if the currently implemented security measures are up to date for the computer system, at block 514, the network security module 304 enters a delay state. This delay state corresponds to the time period for which the network security module 304 periodically queries the security service 306 to obtain the latest security information. After delaying for the predetermined amount of time, the process returns to block 506, where the process of obtaining the latest security information from the security service 306, determining if the currently implemented security measures are up to date for the computer system, and implementing any new security measures, is repeated. As shown in FIG. 5, the exemplary routine 500 does not have an ending terminal as it is designed to operate continuously to protect the computer 302 from computer exploits. However, those skilled in the art will recognize that the routine 500 will terminate if the network security module 304 is powered off, disconnected from the exemplary networked environment 300, or explicitly disabled by a user, as described above. With reference to the alternative starting terminal 520, this entry point represents the situation when the network security module 304 receives update notices from the computer system. As previously discussed, applications adapted to take advantage of the present invention will, as one of the steps to update the computer system, notify the network security module of now current revision information. For example, while updating the anti-virus software, one step of the process would be to issue a notice, intended for the network security module 304, advising the network security module of the now current revision. Thus, at block 522, the network security module receives an update notice. At block 524, the update notice information is stored by the network security module for later use in determining whether the currently implemented security measures are up to date. Operating system updates, as well as other code module updates, may also be adapted to provide notice to the network security module 304 so that the security system may make more informed decisions as to the appropriate security measures necessary to protect any given computer system. After storing the information, the routine 500 proceeds to block 506 where the steps of obtaining the latest security information from the security service 306, determining if the currently implemented security measures are up to date for the computer system, and implementing any new security measures is begun, as described above. As an alternative (not shown), after receiving updated computer system information at block 524, the network security module may wait to obtain security status information until a current delay state is finished. FIG. 6 is a flow diagram illustrating an exemplary routine 600 for broadcasting security information for network security modules, such as network security module 304, in the exemplary networked environment 300. Beginning at block 602, the security service 306 obtains security related information from a variety of sources. For example, the security service 306 would typically obtain information from operating system providers, anti-virus software providers regarding the latest revisions, patches, and updates available, as well as the computer exploits and/or vulnerabilities that are addressed via the various patches and updates. Other sources may also be polled for security related information, including various government agencies, security specialists, and the like. At block 604, the security service 306 obtains information regarding a vulnerability of the computer systems connected to the network 110. This information may come from an operating system provider, an anti-virus software provider, or other party as the vulnerability is detected. At block 606, the security service 306, based on the threat posed by the vulnerability, determines a security level, e.g., red, yellow, or green, as well as protective security measures to be implemented by the network security modules, such as network security module 304, to secure the affected computers from an attack by a computer exploit on the vulnerability. At block 606, the security service 306 broadcasts a security bulletin, comprising the security level and corresponding protective security measures, to the network security modules attached to the network 110, as described above. As discussed above, the security service 306 may broadcast the security bulletin by issuing a network-wide broadcast to all network security modules. This network-wide broadcast may be over the network 110, optionally using the guaranteed delivery option described above, or over a second communication link 314 to the network security devices in the networked environment 300. After broadcasting the security bulletin, the routine 600 terminates. FIG. 7 is a flow diagram illustrating an exemplary routine 700 implemented by a security service 306 to receive and respond to a security information request from a network security module 304. Beginning at block 702, the security service 306 receives a security information request from a network security device 304. As already mentioned, the security information request may include information corresponding to the computer's current configuration. At block 704, according to the particular computer's configuration information in the security information request provided by the network security module, the security service 306 identifies relevant security information corresponding to the computer's current configuration information in the security information request. According to one embodiment, the security service 306 identifies the relevant security information by determining protective security measures needed to protect the computer 302 according to the computer's configuration information. According to an alternative embodiment, the security service 306 identifies the relevant security information by returning all security information corresponding to the particular computer's configuration for further processing by the network security module to determine which protective security measures should be implemented. As yet a further alternative, the security service 306 identifies the relevant security information by returning all security information corresponding to the particular computer's configuration which is then forwarded to the computer 302 from the network security device such that the computer can inform the network security module which protective security measures to implement. Combinations of the above described alternatives may also be utilized, as well as other systems. Accordingly, the present invention should not be construed as limited to any one particular embodiment. At block 706, the security service 306 returns the relevant security information to the requesting network security module 304. Thereafter, the routine 700 terminates. FIG. 8 is a flow diagram illustrating an exemplary method 800 implemented by a network security module 304, for controlling the flow of network traffic between a computer 302 and the network according to security measures obtained from the security service 306. Beginning at block 802, the network security module 304 receives network traffic, including both network traffic coming to the computer 302, as well as network traffic originating with the computer. At decision block 804, a determination is made as to whether the network traffic is to or from a trusted network site, such as the security service, an anti-virus software provider, an operating system provider, and the like. If the network traffic is to or from a trusted network site, the routine proceeds to block 810 where the network traffic is permitted to flow through the network security module 304, and the routine 800 subsequently terminates. However, if the network traffic is not to or from a trusted network site, the routine proceeds to decision block 806. At decision block 806, another determination is made as to whether the network traffic is restricted according to the currently implemented security measures. If the network traffic is not restricted according to the currently implemented security measures, the routine proceeds to block 810, where the network traffic is permitted to flow through the network security module 304, and the routine 800 subsequently terminates. However, if the network traffic is restricted according to the currently implemented security measures, the routine proceeds to block 808, where the network traffic is not permitted to flow through the network security module 304. Thereafter, the routine 800 terminates. While the network security module 304 is interposed between the computer 302 and the Internet 110, the actual embodiment of the network security module may vary. According to one embodiment, the network security module 304 may be implemented as a hardware device, physically external to the computer 302, with connections to the Internet 110 and to the computer 302. FIG. 9 is a pictorial diagram illustrating an exemplary network security module 304 implemented as a hardware device external to the computer 302. As shown in FIG. 9, as an external device, the network security module 304 includes a connection 902 to the network 110 and a corresponding connection 904 to the computer 302. All network activity between the computer 302 and the network 110 is carried on the connection 904 to the computer. The illustrated network security module 304 also includes a secondary computer connection 918 between the computer 302 and the network security module for communicating information between the two. The illustrated network security module 304 further includes an enable/disable switch 906, status indicators 910-916, and an optional connection 908 to an external power source. As previously mentioned, it may be desirable to disable the network security module 304 from enforcing its current security measures. According to the illustrated embodiment of FIG. 9, the enable/disable switch 906 is a toggle switch to disable the network security module 304 when it is desirable to bypass the current security measures, and also to enable the network security module 304 such that it enforces the current security measures it has obtained from the security service 306. Status indicators 910-916 are included to provide a visual indication of the network security module's current status. Status indicators, as previously discusses, are for informational purposes only. They provide optional visual clues to the computer user as to the protective security measures implemented by the network security module 304. Each indicator corresponds to a particular security status. For example, status indicator 910 may correspond to a security level of red, meaning a total lock-down of network activities, and is illuminated in red when the network security module 304 is implementing a total lock-down. Status indicator 912 may correspond to a security level of yellow, i.e., a partial lock-down of network activities, and be illuminated in yellow when the network security module 304 is implementing the partial lock-down. Similarly, status indicator 914 may correspond to the security level green, i.e., free network access, and is illuminated in green when the network security module 304 is permitting unrestricted network access. Status indicator 916 may correspond to the enabled/disabled status of the network security module 304, such that the status indicator is illuminated, perhaps as with a flashing red light, when the network security module is disabled. While the present invention may be implemented as illustrated in FIG. 9, it should be viewed as illustrative only. Numerous modifications and alterations may be made to the physical embodiment illustrated in FIG. 9 without departing from the scope of the present invention. Accordingly, the present invention should not be construed as limited to any particular physical embodiment. As an alternative to a physical embodiment (not shown), the network security module 304 may be a component integrated as a component within the computer 302, or as a sub-component within the computer's network interface. These two embodiments may be especially useful when the computer 302 is connected to the Internet 110 via a wireless connection. As yet a further alternative embodiment, the network security module 304 may be implemented as a software module integrated within the operating system, or as a separate module installed on the computer 302. Accordingly, the network security module 304 should not be construed as limited to any particular embodiment, physical or logical. FIG. 10 is a block diagram illustrating exemplary logical components of a network security module 304, formed in accordance with the present invention. The network security module 304 includes a memory 1002, security status indicator module 1004, a comparison module 1006, a security enforcement module 1008, an update request module 1010, a network connection 1012, a computer connection 1014, a secondary computer connection 1018, and a coder/decoder module 1020. The memory 1002, including volatile and non-volatile memory areas, stores the current security measures to be implemented by the network security module 304. The memory 1002 also stores the configuration information provided to the network security module 304, including current revision information of the operating system, anti-virus software and signatures, applications, and the like. Other information may also be stored in the memory 1002, including trusted location addresses, update sources, and the like. Information such as trusted location addresses, are likely stored in non-volatile memory. The security status indicator module 1004 is for representing to the computer user the network security module's 304 current security status. For example, when the network security module 304 is implemented as a physical device, such as illustrated in FIG. 9, the security status indicator module 1004 controls the status indicators 910-916 according to the network security modules current security status. The comparison module 1006 performs the comparisons between the security information stored in the memory 1002 and the security information obtained from the security service 306 to determine whether the security information stored in the memory 1002 is up to date for the computer's current configuration. The security enforcement module 1008 is that component that implements the security measures necessary to protect the computer 302 from perceived threats. Thus, the security enforcement module 1008 controls the flow of network activities between the computer 302 and the network 110 according to the security measures stored in the memory 1002. The update request module 1010 is used in a poll system to periodically request the latest security information from the security service 306. In a push system, the update request module 1010 may act as a receiver of security information from the security service and work in cooperation with the comparison module 1006 to identify protective security measures for sufficiently protecting the computer 302 according to the information received from the security service 306. Alternatively, the update request module may communicate with the computer 302 to determine/identify the protective security measures for sufficiently protecting the computer according to the information received from the security service 306. All of the components of the network security module 304 are inter-connected via a common system bus 1016. The coder/decoder module 1020 is used to encode and decode secured communications between the network security module 304 and the security service 306, as well as secured communications between the computer 302 and the network security module. Information decoded by the coder/decoder module 1020 is provided to the security enforcement module 1008 for implementing current security measures. According to one embodiment, the secured communications between the computer 302 and the network security module 304 are delivered via the secondary computer connection 1018. However, the present invention should not be construed as limited to comprising a secondary computer connection 1018. In an alternative embodiment, the network security module 304 communicates with the computer 302 using just the principal computer connection 1014. While individual components of a network security module 304 have been described, it should be understood that they are logical components, and may be combined together, or with other components not described, in an actual embodiment. Accordingly, the above-described components should be viewed as illustrative, and not construed as limiting upon the present invention. While the network security module 304 as described, operating alone or in conjunction with anti-virus software, is able to protect a computing device from many computer exploits/attacks, in some situations, certain directed exploits may be able to bypass the network security module and/or the anti-virus software. In particular, one technique used by malicious parties to attack a computing device is to insulate the exploit from detection by using secured communications between an infected computer/exploit origin and the targeted computing device. FIG. 11 is a block diagram illustrating how computer exploits may be delivered to a computing device using secured communications. As an example of how computer exploits may be delivered to a computing device using secured communications, and with reference to FIG. 11, a malicious party on computer 102 has an exploit 112. In order to infect another computer, such as computer 1104, the malicious party may offer the exploit 112 as a legitimate resource/content to others, but offers to deliver it via secured communications. As is known to those skilled in the art, secured communications are encrypted, typically with public and private cryptographic keys, such that only the possessor of a decryption key (the private key) is able to decrypt and view the content of the secured communications. Examples of secured communication protocols include Secure Socket Layer (SSL) and Transport Layer Security (TLS) protocols. Continuing with the present example, an unsuspecting user, via computing device 1104, is duped into believing that the exploit 112 is indeed legitimate content and requests the exploit from the computer 102. The computer 102 and computing device 1104 negotiate and exchange cryptographic keys for encrypting and decrypting the exploit 112. Thereafter, a transmission encoder 1106 encodes the exploit for delivery, and securely delivers the encrypted exploit to the computing device 1104 through the network 110, as indicated by arrow 1108. Because the exploit 122 is delivered in an encrypted state, it is very likely that it can pass a network security module 304 (not shown) and any anti-virus software. Upon reaching the computing device 1104, a transmission decoder module 1110 decodes/decrypts the secured communication and it is presented to the browser display module 1112. Those skilled in the art will recognize that frequently, the transmission decoder module 1110 is an integral part of the browser display module 1112. The browser display module 1112, upon displaying the exploit, enables the exploit 112 to infect the computing device 1104. In accordance with aspects of the present invention, the network security module 304 may be used to protect a computing device from a computer exploit delivered via secured communications. With reference again to FIG. 10, the network security module 304 obtains the cryptographic key necessary to decrypt the secured communication from the computing device via the secondary computer connection 1018. Once the cryptographic key is obtained, the coder/decoder module 1020 temporarily decodes the secured communication for processing. As will be described in greater detail below, if the secured communication is found to violate the security measures implemented by the network security module 304, or to be an exploit, the secured communication is prohibited from reaching the computing device 1104. However, if the secured communication is not in violation of the implemented security measures, and is not an exploit, the secured communication is permitted to flow to the computing device 1104. According to aspects of the present invention, the secondary computer connection 1018 (FIG. 10) may be one of a variety of communication channels to the computing device 1104. For example, the secondary computer connection 1018 may be a Universal Serial Bus (USB) connection, an IEEE 1394 connection, or a standard serial or parallel data connection. As described above, one of the purposes of the secondary computer connection 1018 is to provide a communication channel through which the network security module 304 may obtain a cryptographic decryption key from the transmission decoder 1110 to temporarily decrypt the secured communication. Accordingly, as an alternative embodiment, the secondary computer connection 1018 may also be the computer connection 1014 on which network activity between the computing device and the network 110 is carried. According to this alternative embodiment, the distinction between the computer connection 1014 and the secondary computer connection 1018 is a logical, not physical, distinction. FIG. 12 is a block diagram of an exemplary environment 1200 illustrating how a network security module 304, adapted according to aspects of the present invention, is able to protect a computing device 1104 from a computer exploit 112 delivered to the computing device via a secured communication. Similar to the example of FIG. 11, the malicious party on computer 102 attempts to deliver the computer exploit 112 to the computing device 1104 via secured communications, as indicated by arrow 1108. However, a network security module 304, interposed between the network 110 and the computing device 1104, first obtains the secured communication. As part of enforcing the security measures associated with the current security level, or simply as an ongoing security precaution, the network security module 304 evaluates incoming network activity to determine whether any of the communications are secured communications. Upon detecting a secured communication, the network security module 304 requests the cryptographic decoding key from the transmission decoder module 1110 on the computing device 1102 over the secondary computer connection 1018, as indicated by arrow 1202. Using the cryptographic decoding key, the network security module 304 temporarily decrypts the secured communication and processes the decrypted communication data according to any security measures implemented by the network security module. According to additional aspects of the present invention, the network security module 304, operating in conjunction with anti-virus software, may also deliver the temporarily decrypted communication data to the anti-virus software for its evaluation as an exploit/virus. Upon detecting that the secured communication is either prohibited network activity according to the implemented security measures, or that it represents an exploit as detected by any anti-virus software, the network security module 304 prohibits the secured communication/exploit from reaching the computing device 1104, as indicated by arrow 1204. In this manner, the computing device 1104 is protected, even from communications delivered over secure communication channels. Alternatively, if the secured communication is not in violation of any implemented security measures and is not an exploit, the secure communication is relayed to the computing device 1104. While the above descriptions of FIGS. 11 and 12 illustrate that the transmission decoder 1110 is a separate module from the browser display module 1112, it is for illustration purposes only. Those skilled in the art will readily recognize that the transmission decoder 1110 is quite often an integral component of a browser display module 1112 found on a computing device. FIGS. 13A and 13B illustrate a block diagram of an exemplary routine 1300 for detecting and processing secured communications, in accordance with aspects of the present invention. It should be appreciated that while the exemplary routine 1300 may be implemented on a network security module 304, it may also be separately implemented and executed as a software module operating in conjunction with a browser display module 1112 to protect the computing device 1104 from exploits 112. Beginning at block 1302 (FIG. 13A), the exemplary routine 1300 monitors network activities, and in particular, incoming network activities. Upon detecting an incoming network activity, at decision block 1304, a determination is made as to whether the network activity is a secured communication directed to the protected computing device. If the network activity is not a secured communication directed to the protected computing device, at block 1306, the network activity is relayed to the protected computing device. Thereafter, the process returns to block 1302 for additional monitoring of network activity. While not shown, additional processing may occur on the unsecured network activity. For example, if the exemplary routine 1300 is implemented on a network security module, such as network security module 304, additional processing may occur, such as determining whether the network activity is in violation of any security measures implemented by the network security module. This processing of unsecured network activity has been described above. If the network activity is a secured communication, at block 1308, a decryption key for decrypting the secured communication is obtained. At block 1310, the secured communication is temporarily decrypted using the obtained decryption key. Thereafter, at decision block 1312 (FIG. 13B), a determination is made as to whether the decrypted communication is prohibited according to the security measures implemented by the network security module 304. If the communication represents prohibited network activity, at block 1314, the secured communication is disallowed, i.e., not forwarded to the computing device. Thereafter, the routine 1300 returns to block 1302 (FIG. 13A) to continue monitoring network activity. If the decrypted communication is not prohibited by the implemented security measures, at decision block 1316 an additional determination may be made as to whether the decrypted communication is an exploit. As mentioned above, the network security module 304 may operate in conjunction with external anti-virus software. In this environment, the network security module 304 delivers the temporarily decrypted communication to the anti-virus software for evaluation as to whether it is an exploit, or infected by an exploit. If the decrypted communication is determined to be an exploit, at block 14314, the secured communication is disallowed, and the routine 1300 returns to block 14302 (FIG. 13A) to continue monitoring network activity. Alternatively, if the decrypted communication is determined to not be an exploit, at block 1318, the secured communication is forwarded to the computing device. Thereafter, the routine 1300 returns to block 1302 (FIG. 13A) to continue monitoring network activity. While numerous embodiments, including the preferred embodiment, of the invention have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>As more and more computers, and other computing devices, are inter-connected through various networks, such as the Internet, computer security has become increasingly more important, particularly from invasions or attacks delivered over a network or over an information stream. As those skilled in the art will recognize, these attacks come in many different forms, including, but certainly not limited to, computer viruses, computer worms, system component replacements, denial of service attacks, even misuse/abuse of legitimate computer system features, all of which exploit one or more computer system vulnerabilities for illegitimate purposes. While those skilled in the art will realize that the various computer attacks are technically distinct from one another, for purposes of the present invention and for simplicity in description, all of these attacks will be generally referred to hereafter as computer exploits, or more simply, exploits. When a computer system is attacked or “infected” by a computer exploit, the adverse results are varied, including disabling system devices; erasing or corrupting firmware, applications, or data files; transmitting potentially sensitive data to another location on the network; shutting down the computer system; or causing the computer system to crash. Yet another pernicious aspect of many, though not all, computer exploits is that an infected computer system is used to infect other computers. FIG. 1 is a pictorial diagram illustrating an exemplary networked environment 100 over which a computer exploit is commonly distributed. As shown in FIG. 1 , the typical exemplary networked environment 100 includes a plurality of computers 102 - 108 all inter-connected via a communication network 110 , such as an intranet or via a larger communication network including the global TCP/IP network commonly referred to as the Internet. For whatever reason, a malicious party on a computer connected to the network 110 , such as computer 102 , develops a computer exploit 112 and releases it on the network. The released computer exploit 112 is received by, and infects, one or more computers, such as computer 104 , as indicated by arrow 114 . As is typical with many computer exploits, once infected, computer 104 is used to infect other computers, such as computer 106 as indicated by arrow 116 , which in turn infects yet other computers, such as computer 108 as indicated by arrow 118 . Clearly, due to the speed and reach of the modern computer networks, a computer exploit 112 can “grow” at an exponential rate, and quickly become a local epidemic that quickly escalates into a global computer pandemic. A traditional defense against computer exploits, and particularly computer viruses and worms, is anti-virus software. Generally, anti-virus software scans incoming data, arriving over a network, looking for identifiable patterns associated with known computer exploits. Upon detecting a pattern associated with a known computer exploit, the anti-virus software may respond by removing the computer virus from the infected data, quarantining the data, or deleting the “infected” incoming data. Unfortunately, anti-virus software typically works with “known,” identifiable computer exploits. Frequently, this is done by matching patterns within the data to what is referred to as a “signature” of the exploit. One of the core deficiencies in this exploit detection model is that an unknown computer exploit may propagate unchecked in a network until a computer's anti-virus software is updated to identify and respond to the new computer exploit. As anti-virus software has become more sophisticated and efficient at recognizing thousands of known computer exploits, so too have the computer exploits become more sophisticated. For example, many recent computer exploits are now polymorphic, or in other words, have no identifiable pattern or “signature” by which they can be recognized by anti-virus software in transit. These polymorphic exploits are frequently unrecognizable by anti-virus software because they modify themselves before propagating to another computer system. Another defense that is common today in protecting against computer exploits is a hardware or software network firewall. As those skilled in the art will recognize, a firewall is a security system that protects an internal network from unauthorized access originating from external networks by controlling the flow of information between the internal network and the external networks. All communications originating outside of the firewall are first sent to a proxy that examines the communication, and determines whether it is safe or permissible to forward the communication to the intended target. Unfortunately, properly configuring a firewall so that permissible network activities are uninhibited and that impermissible network activities are denied is a sophisticated and complicated task. In addition to being technically complex, a firewall configuration is difficult to manage. When firewalls are improperly configured, permissible network traffic may be inadvertently shut down and impermissible network traffic may be allowed through, compromising the internal network. For this reason, changes to firewalls are generally made infrequently, and only by those well versed in the subject of technical network design. As yet a further limitation of firewalls, while a firewall protects an internal network, it does not provide any protection for specific computers. In other words, a firewall does not adapt itself to a specific computer's needs. Instead, even if a firewall is used to protect a single computer, it still protects that computer according to the firewall's configuration, not according to the single computer's configuration. Yet another issue related to firewalls is that they do not provide protection from computer exploits originating within the borders established by a firewall. In other words, once an exploit is able to penetrate the network protected by a firewall, the exploit is uninhibited by the firewall. This situation frequently arises when an employee takes a portable computer home (i.e., outside of the corporate firewall protection) and uses it at home in a less secured environment. Unknown to the employee, the portable computer is then infected. When the portable computer is reconnected to the corporate network within the protection of the firewall, the exploit is often free to infect other computers unchecked by the firewall. As mentioned above, computer exploits now also leverage legitimate computer system features in an attack. Thus, many parties other than firewall and anti-virus software providers must now join in defending computers from these computer exploits. For example, operating system providers must now, for economic and contractual reasons, continually analyze their operating system functions to identify weaknesses or vulnerabilities that may be used by a computer exploit. For purposes of the present discussion, any avenue by which a computer exploit may attack a computer system will be generally referred to as a computer system vulnerability, or simply a vulnerability. As vulnerabilities are identified and addressed in an operating system, or other computer system components, drivers, applications, the provider will typically release a software update to remedy the vulnerability. These updates, frequently referred to as patches, should be installed on a computer system in order to secure the computer system from the identified vulnerabilities. However, these updates are, in essence, code changes to components of the operating system, device drivers, or software applications. As such, they cannot be released as rapidly and freely as anti-virus updates from anti-virus software providers. Because these updates are code changes, the software updates require substantial in-house testing prior to being released to the public. Unfortunately, even with in-house testing, a software update may cause one or more other computer system features to break or malfunction. Thus, software updates create a huge dilemma to parties that rely upon the computer systems. More specifically, does a party update their computer systems to protect them from the vulnerability and risk disrupting their computer systems' operations, or does the party refrain from updating their computer systems and run the risk that their computer systems may be infected? Under the present system, there is a period of time, referred to hereafter as a vulnerability window, that exists between when a new computer exploit is released on the network 110 and when a computer system is updated to protect it from the computer exploit. As the name suggests, it is during this vulnerability window that a computer system is vulnerable, or exposed, to the new computer exploit. FIGS. 2A-2B are block diagrams of exemplary timelines illustrating this vulnerability window. In regard to the following discussions regarding timelines, significant times or events will be identified and referred to as events in regard to a timeline. FIG. 2A illustrates a vulnerability window of computer systems with regard to one of the more recent, sophisticated class of computer exploits that are now being released on public networks. As will be described below, this new class of computer exploits take advantage of a system provider's proactive security measures to identify computer system vulnerabilities, and subsequently, create and deliver a computer exploit. With reference to FIG. 2A , at event 202 , an operating system provider identifies the presence of a vulnerability in the released operating system. For example, in one scenario, the operating system provider, performing its own internal analysis of a released operating system, uncovers a previously unknown vulnerability that could be used to attack a computer system. In an alternative scenario, the previously unknown vulnerability is discovered by third parties, including organizations that perform system security analyses on computer systems, and relays information regarding the vulnerability to the operating system provider. Once the operating system provider is aware of the presence of the security vulnerability, the operating system provider addresses the vulnerability which, at event 204 , leads to the creation and release of a patch to secure any computer systems running the operating system. Typically, an operating system provider will make some type of announcement that there is a system patch available, along with a recommendation to all operating system users to install the patch. The patch is usually placed in a known location on the network 110 for downloading and installation onto affected computer systems. Unfortunately, as happens all too often, after the operating system provider releases the patch, at event 206 , a malicious party downloads the patch and, using some reverse engineering as well as any information made public by the operating system or others, identifies the specifics regarding the “fixed” vulnerability in the operating system. Using this information, the malicious party creates a computer exploit to attack the underlying vulnerability. At event 208 , the malicious party releases the computer exploit onto the network 110 . While the goal of issuing a software patch, also known as a “fix,” is to correct an underlying vulnerability, the “fix” is often a complex piece of software code which itself, unfortunately, may create or contain a new vulnerability that could be attacked by a computer exploit created by a malicious party. Thus, in addition to evaluating what the “fix” corrects, the “fix” is also evaluated for potential vulnerabilities. While a “fix” is available, the malicious party realizes that, for various reasons including those described above, not every vulnerable computer system will be immediately upgraded. Thus, at event 208 , the malicious party releases the computer exploit 112 onto the network 110 . The release of the computer exploit 112 opens a vulnerability window 212 , as described above, in which the vulnerable computer systems are susceptible to this computer exploit. Only when the patch is finally installed on a computer system, at event 210 , is the vulnerability window 212 closed for that computer system. While many computer exploits released today are based on known vulnerabilities, such as in the scenario described in regard to FIG. 2A , occasionally, a computer exploit is released on the network 110 that takes advantage of a previously unknown vulnerability. FIG. 2B illustrates a vulnerability window 230 with regard to a timeline 220 under this scenario. Thus, as shown on timeline 220 , at event 222 , a malicious party releases a new computer exploit. As this is a new computer exploit, there is neither an operating system patch nor an anti-virus update available to protect vulnerable computer systems from the attack. Correspondingly, the vulnerability window 230 is opened. At some point after the new computer exploit is circulating on the network 110 , the operating system provider and/or the anti-virus software provider detects the new computer exploit, as indicated by event 224 . As those skilled in the art will appreciate, typically, the presence of the new computer exploit is detected within a matter of hours by both the operating system provider and the anti-virus software provider. Once the computer exploit is detected, the anti-virus software provider can begin its process to identify a pattern, or “signature,” by which the anti-virus software may recognize the computer exploit. Similarly, the operating system provider begins its process to analyze the computer exploit to determine whether the operating system must be patched to protect it from the computer exploit. As a result of these parallel efforts, at event 226 , the operating system provider and/or the anti-virus software provider releases an update, i.e., a software patch to the operating system or an anti-virus update, which addresses the computer exploit. Subsequently, at event 228 , the update is installed on a user's computer system, thereby protecting the computer system and bringing the vulnerability window 230 to a close. As can be seen from the examples above, which are only representative of all of the possible scenarios in which computer exploits pose security threats to a computer system, a vulnerability window exists between the times that a computer exploit 112 is released on a network 110 , and when a corresponding update is installed on a user's computer system to close the vulnerability window. Sadly, whether the vulnerability window is large or small, an infected computer costs the computer's owner substantial amounts of money to “disinfect” and repair, if it is at all possible. This cost can be enormous when dealing with large corporations or entities that may have thousands or hundreds of thousands of devices attached to a network 110 . Such a cost is further amplified by the possibility that such an exploit tamper or destroys customer data, all of which may be extremely difficult or impossible to trace and remedy. What is needed is a system and method for securing a computer system against computer exploits in a responsive manner and according to the individual computer system's needs, even before a protective update is available and/or installed on the computer system. These, and other issues found in the prior art, are addressed by the present invention.
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<SOH> SUMMARY OF THE INVENTION <EOH>In accordance with aspects of the present invention, a network security module interposed between a computing device and a network, for protecting the computing device from an identified security threat over the network is presented. The network security module is positioned such that all network activities between the computing device and the network pass through the network security module. The network security module includes a computing device connection. The computing device connection connects the network security module to the computing device. The network security module also includes a network connection that connects the network security module to the network. It is through the computing device connection and network connection that network activities pass through the network security module. The network security module also includes a decoder module. The decoder module temporarily decrypts secured communications using an obtained decryption key. The network security module further includes a security enforcement module that controls the network activities between the computing device and the network. The security enforcement module implements obtained security measures, thereby protecting the computing device from an identified security threat on the network. In accordance with further aspects of the present invention, a method, implemented on a network security module interposed between a computing device and a network such that all network activities between the computing device and the network must pass through the network security module, for protecting the computing device from an identified security threat, is presented. Protective security measures are obtained. The protective security measures, when enforced, protect the computing device from an identified security threat. A secured communication directed to the computing device is detected. The secured communication is then temporarily decrypted. Thereafter, the protective security measures are implemented on the temporarily decrypted secure communication.
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20040629
|
20100511
|
20050818
|
62970.0
| 0
|
NOBAHAR, ABDULHAKIM
|
SYSTEM AND METHOD FOR PROTECTING A COMPUTING DEVICE FROM COMPUTER EXPLOITS DELIVERED OVER A NETWORKED ENVIRONMENT IN A SECURED COMMUNICATION
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UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,879,863
|
ACCEPTED
|
Tissue homogenizer
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A tissue homogenizer. The tissue homogenizer comprises a first chamber, a pair of blades, a first filter and a second filter. The first chamber has a first opening and a second opening. The blades are disposed in the first chamber. The first filter is disposed in the first chamber between the first opening and the blades. The second filter is disposed in the first chamber between the second opening and the blades. A tissue piece is placed between the first filter and the second filter cut by the blade, and moved by a fluid through the second filter to generate homogenized tissue pieces.
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1. A tissue homogenizer, comprising: a first chamber, comprising a first opening and a second opening; a blade, disposed in the first chamber; and a second filter, disposed in the first chamber between the second opening and the blade, wherein a tissue piece placed in the first chamber is cut by the blade, and a fluid moves a plurality of cut tissue pieces through the second filter to produce a plurality of homogenized tissue pieces. 2. The tissue homogenizer as claimed in claim 1, further comprising a second chamber, comprising a containing portion, with the first chamber disposed therein, wherein the homogenized tissue pieces are impelled by the fluid through the second opening and contained in the containing portion. 3. The tissue homogenizer as claimed in claim 2, wherein the containing portion is a conical. 4. The tissue homogenizer as claimed in claim 2, wherein the first chamber further comprises a third opening, an interstice is formed between the first chamber and an inner wall of the second chamber, and the fluid circulates from the second opening to the first chamber through the third opening along the interstice. 5. The tissue homogenizer as claimed in claim 4, wherein the interstice is narrower than the size of the homogenized tissue pieces. 6. The tissue homogenizer as claimed in claim 2, further comprising a lid and sealing the first opening and the second chamber to limit the flow of the fluid. 7. The tissue homogenizer as claimed in claim 2, wherein the second chamber is a centrifuge tube. 8. The tissue homogenizer as claimed in claim 1, further comprising a first filter disposed in the first chamber between the first opening and the blade. 9. The tissue homogenizer as claimed in claim 1, further comprising a driving mechanism, connected to the blade and driving the blade to cut tissue pieces. 10. The tissue homogenizer as claimed in claim 9, wherein the driving mechanism rotates the blade to cut the tissue piece. 11. The tissue homogenizer as claimed in claim 9, wherein the driving mechanism has a directing mechanism, disposed on the driving mechanism to direct the fluid. 12. The tissue homogenizer as claimed in claim 11, wherein the directing mechanism is a vane.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tissue homogenizer and in particular to a tissue homogenizer for homogenizing live histiocyte. 2. Description of the Related Art In conventional culture preparation, a tissue piece is cut in a culture dish by scalpel blade, soaked in protease enzyme to separate cells from cytoplasm, and applied to a culture experiment. When cut by scalpel blade, however, the tissue piece is easily polluted and difficult to collect. This conventional method of cutting tissue (homogenizing) wasteful; and when primary tissue is limited, may prevent successful culture. U.S. Pat. No. 4,874,137 teaches homogenization of tissue piece by ultrasonic wave. U.S. Pat. No. 4,509,695 teaches homogenization of tissue which is originally cooled by liquid nitrogen and then pulverized. U.S. Pat. Nos. 5,829,696, 5,533,683, 4,525,395 and 4,509,695 teach homogenization of tissue piece by pulverizing. The methods mentioned above can damage histiocytes. As well, the degree of homogenization is controlled by an operator creating inconsistent result. SUMMARY OF THE INVENTION The present invention comprises a first chamber, a pair of blades, a first filter and a second filter. The first chamber has a first opening and a second opening. The blades are disposed in the first chamber. The first filter is disposed in the first chamber between the first opening and the blades. The second filter is disposed in the first chamber between the second opening and the blades. A tissue piece is placed between the first filter and the second filter for cutting by the blade and a fluid moves the cut tissue pieces through the second filter for homogenization. The present invention successively cuts, filters, and collects finally the homogenized tissue pieces in a sealed device. The present invention produces homogenized tissue pieces at lower cost in a shorter time, and prevents tissue waste. As well, because the present invention homogenizes the tissue piece by cutting, histiocytes are undamaged and can be applied in live histiocyte culture. Additionally, the present invention provides precise control of homogenized tissue piece by size the filter. BRIEF DESCRIPTION OF THE DRAWINGS The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: FIG. 1 shows the main structure of the tissue homogenizer of the present invention; FIG. 2 shows homogenization of tissue pieces; FIG. 3 shows the complete tissue homogenizer of the present invention; FIG. 4 shows the complete tissue homogenizer homogenizing tissue pieces. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows the main structure of the tissue homogenizer 100 of the present invention comprising a first chamber 110, a driving mechanism 121, a pair of vanes (directing mechanism) 122, a pair of blades 123, a first filter 131 and a second filter 132. The first chamber 110 has a first opening 111 and a second opening 112. The driving mechanism 121 extends into the first chamber 110 from the first opening 111. The vanes 122 and the blades 123 are disposed on the driving mechanism 121 in the first chamber 110. The first filter 131 is disposed between the vanes 122 and the blades 123. The second filter 132 is disposed between the second opening 112 and the blades 123. FIG. 2 shows the tissue homogenizer 100 homogenizing tissue pieces 150. The tissue pieces 150 are disposed between the first filter 131 and the second filter 132. The first filter 131 restricts the distribution of the tissue pieces 150. The first chamber 110 is filled with a fluid. The driving mechanism 121 is rotated to drive the vanes 122 and the blades 123. The blades 123 cut the tissue pieces 150. The vanes 122 impel the fluid from the first filter 131 to the second filter 132. The fluid moves the cut tissue pieces filtered by the second filter 132 generating homogenized tissue pieces 151. The first filter 131 can be omitted to simplify the present invention, wherein distribution of the tissue pieces 150 is restricted by the first chamber 110. FIG. 3 shows the complete tissue homogenizer, further comprising a second chamber 140 with a containing portion 141. The containing portion 141 is conical and disposed at an end of the second chamber 140. The first chamber 110 is disposed in the second chamber 140 at an interstice d from the inner wall thereof. Additionally, the first chamber 110 further comprises third openings 113. The fluid flows from the second opening 112, along the interstice d, and back to the first chamber 110 through the third openings 113. A lid 160 seals the first opening 111 and the second chamber 140 to limit the flow of the fluid. In FIG. 4, homogenized tissue pieces 151 are impelled by the fluid through the second opening 112 and contained in the containing portion 141. The fluid circulates from the second opening 112 to the first chamber 110 through the third opening 113 along the interstice d. The fluid is directed by vanes 122. Thus, the fluid is recycled. The width of the interstice d is smaller than the homogenized tissue pieces 151 to prevent reflux into the first chamber 110. The second chamber 140 is a centrifuge tube. The fluid is culture medium. The homogenized tissue pieces 151 provide live histiocytes. The present invention can also receive fluid directly into the first opening 111 to direct the homogenized tissue pieces 151. Additionally, the second chamber can be replaced by a third filter with through holes smaller than the second filter 132 to gather homogenized tissue pieces 151. The present invention successively cuts, filters, and collects finally the homogenized tissue pieces in a sealed device. The present invention produces homogenized tissue pieces at lower cost in a shorter time, and prevents tissue waste. As well, because the present invention homogenizes the tissue piece by cutting, histiocytes are undamaged and can be applied in live histiocyte culture. Additionally, the present invention provides precise control of homogenized tissue piece by size the filter. While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a tissue homogenizer and in particular to a tissue homogenizer for homogenizing live histiocyte. 2. Description of the Related Art In conventional culture preparation, a tissue piece is cut in a culture dish by scalpel blade, soaked in protease enzyme to separate cells from cytoplasm, and applied to a culture experiment. When cut by scalpel blade, however, the tissue piece is easily polluted and difficult to collect. This conventional method of cutting tissue (homogenizing) wasteful; and when primary tissue is limited, may prevent successful culture. U.S. Pat. No. 4,874,137 teaches homogenization of tissue piece by ultrasonic wave. U.S. Pat. No. 4,509,695 teaches homogenization of tissue which is originally cooled by liquid nitrogen and then pulverized. U.S. Pat. Nos. 5,829,696, 5,533,683, 4,525,395 and 4,509,695 teach homogenization of tissue piece by pulverizing. The methods mentioned above can damage histiocytes. As well, the degree of homogenization is controlled by an operator creating inconsistent result.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention comprises a first chamber, a pair of blades, a first filter and a second filter. The first chamber has a first opening and a second opening. The blades are disposed in the first chamber. The first filter is disposed in the first chamber between the first opening and the blades. The second filter is disposed in the first chamber between the second opening and the blades. A tissue piece is placed between the first filter and the second filter for cutting by the blade and a fluid moves the cut tissue pieces through the second filter for homogenization. The present invention successively cuts, filters, and collects finally the homogenized tissue pieces in a sealed device. The present invention produces homogenized tissue pieces at lower cost in a shorter time, and prevents tissue waste. As well, because the present invention homogenizes the tissue piece by cutting, histiocytes are undamaged and can be applied in live histiocyte culture. Additionally, the present invention provides precise control of homogenized tissue piece by size the filter.
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20040629
|
20070918
|
20050630
|
75483.0
| 0
|
ROSENBAUM, MARK
|
TISSUE HOMOGENIZER
|
UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,880,025
|
ACCEPTED
|
Polymer and metal composite implantable medical devices
|
A device and a method of manufacturing an implantable medical device, such as a stent, are described herein. The device includes a metallic region composed of a bioerodable metal and a polymer region composed of a biodegradable polymer contacting the metallic region. The metallic region may erode at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. In certain embodiments, the polymer region is an outer layer and the metallic region is an inner layer of the device. A further aspect of the invention includes device and a method of manufacturing the device that includes a mixture of a biodegradable polymer and bioerodable metallic particles. The mixture may be used to fabricate an implantable medical device or to coat an implantable medical device. In some embodiments, the metallic particles are metallic nanoparticles.
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1. An implantable medical device, comprising: a metallic region comprising a bioerodable metal; and a polymer region comprising a biodegradable polymer contacting the metallic region, wherein the metallic region erodes at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. 2. The device of claim 1, wherein the implantable medical device is a stent. 3. The device of claim 1, wherein the polymer comprises at least one material selected from the group consisting of poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), and polyester amide. 4. The device of claim 1, wherein the metallic region comprises at least one material selected from the group consisting of magnesium, zinc, and iron. 5. The device of claim 1, wherein the biodegradable polymer comprises a pure or substantially pure biodegradable polymer. 6. The device of claim 1, wherein the biodegradable polymer comprises a mixture of at least two types of biodegradable polymers. 7. The device of claim 1, wherein the biodegradable polymer comprises a bulk eroding polymer. 8. The device of claim 1, wherein the biodegradable polymer comprises a surface eroding polymer. 9. The device of claim 1, wherein the bioerodable metal comprises a pure or substantially pure bioerodable metal. 10. The device of claim 1, wherein the bioerodable metal comprises a mixture comprising at least two types of metals. 11. The device of claim 1, wherein the bioerodable metal comprises an alloy comprising at least two types of metals. 12. The device of claim 1, wherein the polymer region comprises an active agent. 13. The device of claim 1, wherein the metallic region comprises pores comprising an active agent. 14. The device of claim 1, wherein the polymer region is configured to release an active agent. 15. The device of claim 1, wherein the metallic region erodes at a faster rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. 16. The device of claim 1, wherein the polymer region comprises an outer layer and the metallic region comprises an inner layer of the device. 17. The device of claim 1, wherein the polymer region is configured to delay, inhibit, or prevent erosion of the metallic region. 18. The device of claim 1, wherein the polymer region is configured to inhibit or prevent erosion of the metallic region in a manner that allows the metallic region to provide mechanical support to a bodily lumen. 19. The device of claim 1, wherein the polymer region is configured to inhibit or prevent erosion of the metallic region for at least a portion of, all of, or longer than the time period that the metallic region is desired to provide mechanical support of a bodily lumen. 20. The device of claim 1, wherein the metallic region is configured to completely or almost completely erode before the polymer region is completely or almost completely eroded. 21. The device of claim 1, wherein the metallic region is configured to erode when the metallic region is exposed to bodily fluids due to degradation of the polymer region. 22. The device of claim 1, wherein the polymer region is configured to delay, inhibit, or prevent exposure of the metallic region to bodily fluids a majority of, all of, or longer than a desired treatment time of the implantable medical device. 23. The device of claim 1, wherein the metallic region starts to erode when the polymer region is partially degraded. 24. The device of claim 1, wherein the metallic region starts to erode when the polymer region is completely degraded. 25. The device of claim 1, wherein the metallic region starts to erode when a majority of the polymer region is degraded. 26. The device of claim 1, wherein the polymer region is configured to have a water diffusivity that inhibits or prevents erosion of the metallic region for a selected time period. 27. The device of claim 1, wherein the device comprises greater radial strength than an equivalent device fabricated from the biodegradable polymer, wherein the equivalent device comprises the same dimensions and structure as the device. 28. The device of claim 1, wherein the device comprises greater flexibility than an equivalent device fabricated from the metal, wherein the equivalent device comprises the same dimensions and structure as the device. 29. The device of claim 1, wherein the device comprises a stent with a smaller profile than an equivalent device fabricated from the biodegradable polymer, wherein the equivalent device comprises an equivalent stent with the same dimensions and structure as the stent. 30. The device of claim 29, wherein the smaller profile comprises thinner struts. 31. The device of claim 1, wherein the device comprises sufficient radio-opacity to be imaged by X-Ray radiation. 32. The device of claim 1, wherein the metallic region comprises a cylindrical or substantially cylindrical coil or mesh of metallic wire. 33. The device of claim 1, wherein the metallic region comprises a pattern of struts on a metallic tube. 34. The device of claim 1, wherein the polymer region comprises a coating comprising the biodegradable polymer on the metallic region. 35. The device of claim 1, wherein the polymer region comprises a uniform or substantially uniform composition and uniform or substantially uniform erosion rate. 36. The device of claim 1, wherein the metallic region comprises a uniform or substantially uniform composition and uniform or substantially uniform erosion rate. 37. The device of claim 1, wherein the polymer region comprises at least two layers, wherein at least two layers comprise different erosion rates. 38. The device of claim 1, wherein the metallic region comprises at least two layers, wherein at least two layers comprise different erosion rates. 39. The device of claim 1, further comprising a second metallic region contacting the polymer region, wherein the polymer region is between the metallic region and the second metallic region. 40. The device of claim 1, further comprising a second polymer region contacting the metallic region, wherein the metallic region is between the polymer region and the second polymer region. 41. A method of manufacturing an implantable medical device, comprising: forming a metallic region comprising a bioerodable metal; and forming a polymer region comprising a biodegradable polymer contacting the metallic region, wherein the metallic region erodes at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. 42. The method of claim 41, wherein the implantable medical device is a stent. 43. The method of claim 41, wherein the polymer region comprises at least one material selected from the group consisting of poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), and polyester amide. 44. The method of claim 41, further comprising modifying the polymer region to obtain a desired erosion rate. 45. The method of claim 41, further comprising modifying the metallic region to obtain a desired erosion rate. 46. The method of claim 41, wherein forming the metallic region comprises forming a cylindrical or substantially cylindrical coil or mesh of metallic wire. 47. The method of claim 41, wherein forming the metallic region comprises forming a pattern of struts on a metallic tube. 48. The method of claim 41, wherein forming the polymer region comprising the biodegradable polymer contacting the metallic region comprises forming a coating comprising the biodegradable polymer on the metallic region. 49. The method of claim 41, further comprising forming a second metallic region contacting the polymer region, wherein the polymer region is between the metallic region and the second metallic region. 50. The method of claim 41, further comprising forming a second polymer region contacting the metallic region, wherein the metallic region is between the polymer region and the second polymer region. 51. An implantable medical device, comprising: a mixture comprising a biodegradable polymer and bioerodable metallic particles. 52. The device of claim 51, wherein the device is fabricated from the mixture. 53. The device of claim 51, wherein the device is coated with the mixture. 54. The device of claim 51, wherein the mixture further comprises a biostable polymer and/or biostable metallic particles. 55. The device of claim 51, wherein the mixture comprises metallic particles that include at least one particle composed of a mixture or alloy of at least of one bioerodable metal and at least one biostable metal. 56. The device of claim 51, wherein the implantable medical device is a stent. 57. The device of claim 51, wherein the polymer comprises at least one material selected from the group consisting of poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), and polyester amide. 58. The device of claim 51, wherein the bioerodable metallic particles comprise bioerodable metallic nanoparticles. 59. The device of claim 51, wherein the bioerodable metallic particles comprise at least one material selected from the group consisting of magnesium, magnesium oxide, zinc, zinc oxide, iron, and iron oxide. 60. The device of claim 51, wherein the device is bioerodable. 61. The device of claim 51, wherein the device is configured to completely or almost completely erode in a selected period of time. 62. The device of claim 51, wherein the device comprises greater radial strength than an equivalent device fabricated from the biodegradable polymer, wherein the equivalent device comprises the same dimensions and structure as the device. 63. The device of claim 51, wherein the device comprises greater flexibility than an equivalent device fabricated from the biodegradable polymer, wherein the equivalent device comprises the same dimensions and structure as the device. 64. The device of claim 51, wherein the device is a stent with a smaller profile than an equivalent stent fabricated from the biodegradable polymer, wherein the equivalent device comprises an equivalent stent with the same radial strength and the same dimensions and structure as the device. 65. The device of claim 64, wherein the smaller profile comprises thinner struts. 66. The device of claim 51, wherein the device comprises sufficient radio-opacity to be imaged by X-Ray radiation. 67. The device of claim 51, wherein the mixture further comprises an active agent. 68. A method of manufacturing an implantable medical device, comprising: mixing a biodegradable polymer and bioerodable metallic particles to form a biodegradable mixture; and using the mixture to fabricate an implantable medical device or to coat an implantable medical device. 69. The method of claim 68, further comprising mixing a biostable polymer and/or biostable metallic particles with the biodegradable polymer and the bioerodable metallic particles. 70. The method of claim 68, further comprising mixing metallic particles that include at least one particle composed of a mixture or alloy of at least of one bioerodable metal and at least one biostable metal with the biodegradable polymer and the bioerodable metallic particles. 71. The method of claim 68, wherein the implantable medical device is a stent. 72. The method of claim 68, wherein the polymer comprises at least one material selected from the group consisting of poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), and polyester amide. 73. The method of claim 68, wherein the bioerodable metallic particles comprise bioerodable metallic nanoparticles. 74. The method of claim 68, wherein the bioerodable metallic particles comprise at least one material selected from the group consisting of magnesium, magnesium oxide, zinc, zinc oxide, iron, and iron oxide. 75. The method of claim 68, wherein the device is bioerodable. 76. The method of claim 68, wherein the device is configured to completely or almost completely erode in a selected period of time. 77. The method of claim 68, wherein the device fabricated from the mixture comprises greater radial strength than an equivalent device fabricated from the biodegradable polymer, wherein the equivalent device comprises the same dimensions and structure as the device. 78. The method of claim 68, wherein the device fabricated from the mixture comprises greater flexibility than an equivalent device fabricated from the biodegradable polymer, wherein the equivalent device comprises the same dimensions and structure as the device. 79. The method of claim 68, wherein the device fabricated from the mixture is a stent with a smaller profile than an equivalent stent fabricated from the biodegradable polymer, wherein the equivalent device comprises an equivalent stent with the same radial strength and the same dimensions and structure as the device. 80. The method of claim 79, wherein the smaller profile comprises thinner struts. 81. The method of claim 68, wherein the device comprises sufficient radio-opacity to be imaged by X-Ray radiation. 82. The method of claim 68, further comprising modifying the composition of the mixture of the biodegradable polymer and the bioerodable metallic particles to obtain a desired property. 83. The method of claim 82, wherein the desired property comprises a desired degree of radio-opacity of the device. 84. The method of claim 82, wherein the desired property comprises a desired radial strength of the device. 85. The method of claim 82, wherein the desired property comprises a desired erosion rate. 86. The method of claim 82, wherein the desired property comprises a desired radial strength of the device. 87. The method of claim 82, wherein the desired property comprises a desired erosion rate. 88. The method of claim 82, wherein modifying the composition of the mixture of the biodegradable polymer and the bioerodable metallic particles comprises modifying the ratio of the biodegradable polymer to the metallic particles in the mixture. 89. The method of claim 82, wherein modifying the composition of the mixture of the biodegradable polymer and the bioerodable metallic particles comprises modifying the composition of the metallic particles. 90. The method of claim 82, wherein modifying the composition of the mixture of the biodegradable polymer and the bioerodable metallic particles comprises modifying the concentration of at least one type of metallic particle in the mixture. 91. The method of claim 82, wherein modifying the composition of the mixture of the biodegradable polymer and the bioerodable metallic particles comprises modifying the composition of at least one metallic particle. 92. The method of claim 68, wherein mixing the biodegradable polymer and the bioerodable metallic particles comprises mixing the biodegradable polymer and the bioerodable metallic particles in an extruder. 93. The method of claim 68, further comprising mixing an active agent with the biodegradable polymer and the bioerodable metallic particles. 94. The method of claim 68, wherein using the mixture to fabricate the implantable medical device comprises forming a tube from the mixture. 95. The method of claim 68, wherein using the mixture to fabricate the implantable medical device comprises forming a tube from the mixture using an extruder. 96. The method of claim 68, wherein using the mixture to fabricate the implantable medical device comprises forming a sheet from the mixture, and forming a tube from the sheet. 97. The method of claim 68, wherein using the mixture to fabricate the implantable medical device comprises forming a pattern comprising a pattern of struts on a tube comprising the mixture. 98. The method of claim 68, wherein forming a pattern comprises laser cutting a pattern.
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CROSS-REFERENCE This is a continuation-in-part of application Ser. No. 10/767,296 filed on Jan. 28, 2004, which is a divisional application of application Ser. No. 10/235,033, which was filed on Sep. 3, 2002, which is a continuation of application Ser. No. 09/797,313, filed on Mar. 1, 2001, which is a division of application Ser. No. 08/837,993, filed on Apr. 15, 1997, and issued Jun. 5, 2001 as U.S. Pat. No. 6,240,616. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to polymer and metal composite implantable medical devices, such as stents. 2. Description of the State of the Art This invention relates to radially expandable endoprostheses which are adapted to be implanted in a bodily lumen. An “endoprosthesis” corresponds to an artificial device that is placed inside the body. A “lumen” refers to a cavity of a tubular organ such as a blood vessel. A stent is an example of an endoprosthesis. Stents are generally cylindrically shaped devices which function to hold open and sometimes expand a segment of a blood vessel or other anatomical lumen such as urinary tracts and bile ducts. Stents are often used in the treatment of atherosclerotic stenosis in blood vessels. “Stenosis” refers to a narrowing or constriction of the diameter of a bodily passage or orifice. In such treatments, stents reinforce body vessels and prevent restenosis following angioplasty in the vascular system. “Restenosis” refers to the reoccurrence of stenosis in a blood vessel or heart valve after it has been treated (as by balloon angioplasty or valvuloplasty) with apparent success. Stents have been made of many materials including metals and polymers. Polymer materials include both biostable and biodegradable polymer materials. Metallic stents are typically formed from biostable metals. However, bioerodable metal stents have been described. U.S. Pat. No. 6,287,332 B1 to Bolz et al., U.S. Pat. Appl. Pub. No. 2002/0004060 A1 to Heublein et. al. The cylindrical structure of stents is typically composed of a scaffolding that includes a pattern or network of interconnecting structural elements or struts. The scaffolding can be formed from wires, tubes, or planar films or sheets of material rolled into a cylindrical shape. In addition, a medicated stent may be fabricated by coating the surface of either a metallic or polymeric scaffolding with a polymeric carrier. The polymeric carrier can include an active agent or drug. Furthermore, the pattern that makes up the stent allows the stent to be radially expandable and longitudinally flexible. Longitudinal flexibility facilitates delivery of the stent and radial rigidity is needed to hold open a bodily lumen. The pattern should be designed to maintain the longitudinal flexibility and radial rigidity required of the stent. A number of techniques have been suggested for the fabrication of stents from tubes and planar films or sheets. One such technique involves laser cutting or etching a pattern onto a material. A pattern may be formed on a planar film or sheet of a material which is then rolled into a tube. Alternatively, a desired pattern may be formed directly onto a tube. Other techniques involve forming a desired pattern into a sheet or a tube via chemical etching or electrical discharge machining. Laser cutting of stents has been described in a number of publications including U.S. Pat. No. 5,780,807 to Saunders, U.S. Pat. No. 5,922,005 to Richter and U.S. Pat. No. 5,906,759 to Richter. The first step in treatment of a diseased site with a stent is locating a region that may require treatment such as a suspected lesion in a vessel, typically by obtaining an X-Ray image of the vessel. To obtain an image, a contrast agent which contains a radio-opaque substance such as iodine is injected into a vessel. Radio-opaque refers to the ability of a substance to absorb X-Rays. The X-ray image depicts a profile of the vessel from which a physican can identify a potential treatment region. The treatment then involves both delivery and deployment of the stent. “Delivery” refers to introducing and transporting the stent through a bodily lumen to a region in a vessel that requires treatment. “Deployment” corresponds to the expanding of the stent within the lumen at the treatment region. Delivery and deployment of a stent are accomplished by positioning the stent about one end of a catheter, inserting the end of the catheter through the skin into a bodily lumen, advancing the catheter in the bodily lumen to a desired treatment location, expanding the stent at the treatment location, and removing the catheter from the lumen. In the case of a balloon expandable stent, the stent is mounted about a balloon disposed on the catheter. Mounting the stent typically involved compressing or crimping the stent onto the balloon. The stent is then expanded by inflating the balloon. The balloon may then be deflated and the catheter withdrawn. In the case of a self-expanding stent, the stent may secured to the catheter via a retractable sheath or a sock. When the stent is in a desired bodily location, the sheath may be withdrawn allowing the stent to self-expand. The stent may be visualized during delivery and deployment using X-Ray imaging if it contains radio-opaque materials. By looking at the position of stent with respect to the treatment region, the stent may be advanced with the catheter to a location. After implantation of the stent additional contrast agent may be injected to obtain an image of the treated vessel. There are several desirable properties for a stent to have that greatly facilitate the delivery, deployment, and treatment of a diseased vessel. Longitudinal flexibility is important for successful delivery of the stent. In addition, radial strength is vital for holding open a vessel. Also, as the profile of a stent decreases, the easier is its delivery, and the smaller the disruption of blood flow. Additionally, in order to visualize a stent during deployment it is also important for a stent to include at least some radio-opaque materials. Furthermore, it is also desirable for a stent to be bioeroable. Many treatments utilizing stents require the presence of a stent in the vessel for between about six and twelve months. Stents fabricated from biodegradable polymers may be configured to completely erode after the clinical need for them has ended. Although current biodegradable polymer-fabricated stents, biostable metal stents, bierodable metal stents, and polymer-coated metal stents each have certain advantages, they also possess potential shortcomings. Biodegradable polymer-fabricated stents may be configured to degrade after they are no longer needed and also possess a desired degree of flexibility. However, in order to have adequate mechanical strength, such stents require significantly thicker struts than a metallic stent, which results in a larger profile. Inadequete radial strength may contribute to relatively high incidence of recoil of polymer stents after implantation into vessels. In addition, biodegradable polymers, unlike metals, are not radio-opaque which makes visualization of a stent difficult during delivery and after deployment. Moreover, although biostable metallic stents possess favorable mechanical properties, are radio-opaque, and have smaller profiles than polymer-fabricated stents, they are not bioerodable. Bioerodable metallic stents tend to erode too fast, resulting in complete or nearly complete bioerosion before the end of a treatment time. Therefore, there is a present need for stents that possess more of the favorable properties of polymers and metals. SUMMARY OF THE INVENTION The present invention is directed to implantable medical devices, such as stents, and methods of manufacturing such devices that include a metallic region composed of a bioerodable metal and a polymer region composed of a biodegradable polymer contacting the metallic region. The metallic region may erode at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. In certain embodiments, the polymer region is an outer layer and the metallic region is an inner layer of the device. In some embodiments, the metallic region erodes at a faster rate than the polymer region when exposed to bodily fluids. Further aspects of the invention are directed to implantable medical devices and methods of manufacturing such devices that include a mixture of a biodegradable polymer and bioerodable metallic particles. In some embodiments, the metallic particles are metallic nanoparticles. In some embodiments, the mixture may be used to coat an implantable medical device. In other embodiments, an implantable medical device may be fabricated from the mixture. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts an example of a stent. FIGS. 2 and 3 depict degradation as a function of time for a polymer. FIG. 4 depicts a schematic illustration of a cross-section of a strut. FIGS. 5A and 5B depict erosion profiles of a stent. FIG. 6 depicts a schematic illustration of a cross-section of a strut. DETAILED DESCRIPTION OF THE INVENTION The term “implantable medical device” is intended to include self-expandable stents, balloon-expandable stents, stent-grafts, and grafts. The structural pattern of the device can be of virtually any design. A stent, for example, may include a pattern or network of interconnecting structural elements or struts. FIG. 1 depicts a three-dimensional view of a stent 100 which shows struts 105. The implantable medical device has a cylindrical axis 110. The pattern shown in FIG. 1 should not be limited to what has been illustrated as other stent patterns are easily applicable with the method of the invention. A stent such as stent 100 may be fabricated from a tube by forming a pattern with a technique such as laser cutting or chemical etching. Various embodiments of the present invention relate to implantable medical devices and methods of manufacturing such devices that possess desired combinations and degrees of properties such as radial strength, flexibility, radio-opacity, low profile or form factor, biodegradability, and drug delivery capability. Implantable medical devices that possess certain desired combinations and degrees of properties may not be fabricated either from polymeric or metallic materials alone. As indicated above, polymeric materials typically are flexible. Also, many biodegradable polymers have erosion rates that make them suitable for treatments that require the presence of a device in a vessel only for a six to twelve month time frame. In addition, metals are radio-opaque and have favorable mechanical properties such as relatively high tensile strength. The embodiments of the present invention involve composite devices and methods of making composite devices that possess desirable properties of polymers and metals to a greater extent than previous composite devices. For stents made from a biodegradable polymer, the stent may be intended to remain in the body for a duration of time until its intended function of, for example, maintaining vascular patency and/or drug delivery is accomplished. For biodegradable polymers used in coating applications, after the process of degradation, erosion, absorption, and/or resorption has been completed, no polymer will remain on the stent. In some embodiments, very negligible traces or residue may be left behind. The duration is typically in the range of six to twelve months. It is desirable for the stent to provide mechanical support to a vessel for approximately this duration. Therefore, a preferred erosion profile in such treatments may be slow or minimal degradation for as long as mechanical support for the vessel may be desired. This preferred erosion profile may then include a rapid degradation occurring approximately after the stent is no longer required. A stent configuration that may achieve such a profile may include a slow eroding, flexible outer region and a fast eroding, stiff, strong inner region that provides mechanical support as long as support is desired. Additionally, it would be also be desirable for such a stent to have a small form factor and radio-opacity. Although biodegradable polymer-fabricated stents are configured to erode, they are not radio-opaque. In addition, in order to have adequate strength, the struts may be significantly thicker than struts in metal stents. For example, a polymer-fabricated stent composed of poly(L-lactic acid) may require struts more than 50% thicker struts than a metallic stent. On the other hand, a metallic stent fabricated from a bioerodable metal, such as magnesium, erodes too quickly to remain intact for the typical treatment time of six to twelve months. Polymers can be biostable, bioabsorbable, biodegradable, or bioerodable. Biostable refers to polymers that are not biodegradable. The terms biodegradable, bioabsorbable, and bioerodable, as well as degraded, eroded, and absorbed, are used interchangeably and refer to polymers that are capable of being completely eroded or absorbed when exposed to bodily fluids such as blood and can be gradually resorbed, absorbed and/or eliminated by the body. Biodegradation refers generally to changes in physical and chemical properties that occur in a polymer upon exposure to bodily fluids as in a vascular environment. The changes in properties may include a decrease in molecular weight, deterioration of mechanical properties, and decrease in mass due to erosion or absorption. Mechanical properties may correspond to strength and modulus of the polymer. Deterioration of the mechanical properties of the polymer decreases the ability of a stent, for example, to provide mechanical support in a vessel. The decrease in molecular weight may be caused by, for example, hydrolysis and/or metabolic processes. Hydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water. Consequently, the degree of degradation of a polymer is strongly dependent on the diffusivity of water in the polymer. A decrease in molecular weight of the polymer can result in deterioration of mechanical properties and contributes to erosion or absorption of the polymer into the bodily fluids. Therefore, the time frame of degradation of a polymer part is dependent on water diffusion, hydrolysis, decrease in molecular weight, and erosion. Furthermore, polymer erosion spans a continuum from bulk eroding to surface eroding. Bulk eroding refers to degradation of a polymer throughout the bulk of a polymer part exposed to bodily fluids. Alternatively, a polymer may be surface eroding. A surface eroding polymer typically has relatively low water diffusivity. As a result, surface erosion is a heterogeneous process in which degradation and erosion tend to occur at or near a surface of the polymer exposed to the bodily fluids. Furthermore, the time frame of the degradation of various properties depends on such properties as the diffusivity of water in the polymer and whether the polymer is bulk eroding or surface eroding. For example, for a bulk eroding polymer, the molecular weight loss, deterioration of mechanical properties, and erosion tend to occur sequentially over different time frames. FIG. 2 illustrates degradation as a function of time for a bulk eroding polymer part. A curve 120 represents the decrease in molecular weight that occurs within the bulk of the polymer material. The decrease in molecular weight causes deterioration in mechanical properties of the polymer, which is shown by a curve 125. A curve 130 represents the total erosion of the polymer. Some bulk eroding polymers, may exhibit relatively little erosion even with a substantial loss of molecular weight and deterioration of mechanical properties, as depicted in FIG. 2. For such polymers, much of the erosion may occur over a relatively short time frame, as in a time period 135. Additionally, the water diffusivity in the polymer increases as a bulk-eroding polymer degrades. Alternatively, for a surface eroding polymer, changes in the various properties may occur over similar time frames since the degradation is limited to a region at or near an exposed surface. In FIG. 3, a curve 140 depicts the total erosion as a function of time for a surface-eroding polymer part. The erosion rate is substantially dependent on the surface area of a part. Since degradation is heterogeneous, the decrease in molecular weight and deterioration of the mechanical properties occur at or near the surface of a surface-eroding polymer part. In the bulk or away from the surface of a surface-eroding polymer part, the molecular weight and mechanical properties are unchanged or substantially unchanged. Representative examples of polymers that may be used to fabricate an implantable medical device using the methods disclosed herein include, but are not limited to, poly(N-acetylglucosamine) (Chitin), Chitoson, poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), polyester amide, poly(glycolic acid-co-trimethylene carbonate), co-poly(ether-esters) (e.g. PEO/PLA), polyphosphazenes, biomolecules (such as fibrin, fibrinogen, cellulose, starch, collagen and hyaluronic acid), polyurethanes, silicones, polyesters, polyolefins, polyisobutylene and ethylene-alphaolefin copolymers, acrylic polymers and copolymers other than polyacrylates, vinyl halide polymers and copolymers (such as polyvinyl chloride), polyvinyl ethers (such as polyvinyl methyl ether), polyvinylidene halides (such as polyvinylidene chloride), polyacrylonitrile, polyvinyl ketones, polyvinyl aromatics (such as polystyrene), polyvinyl esters (such as polyvinyl acetate), acrylonitrile-styrene copolymers, ABS resins, polyamides (such as Nylon 66 and polycaprolactam), polycarbonates, polyoxymethylenes, polyimides, polyethers, polyurethanes, rayon, rayon-triacetate, cellulose, cellulose acetate, cellulose butyrate, cellulose acetate butyrate, cellophane, cellulose nitrate, cellulose propionate, cellulose ethers, and carboxymethyl cellulose. Additional representative examples of polymers that may be especially well suited for use in fabricating an implantable medical device according to the methods disclosed herein include ethylene vinyl alcohol copolymer (commonly known by the generic name EVOH or by the trade name EVAL), poly(butyl methacrylate), poly(vinylidene fluoride-co-hexafluororpropene) (e.g., SOLEF 21508, available from Solvay Solexis PVDF, Thorofare, N.J.), polyvinylidene fluoride (otherwise known as KYNAR, available from ATOFINA Chemicals, Philadelphia, Pa.), ethylene-vinyl acetate copolymers, and polyethylene glycol. Additionally, some metals are considered bioerodable since they tend to erode or corrode relatively rapidly when exposed to bodily fluids. Biostable metals refer to metals that are not bioerodable. Biostable metals have negligible erosion or corrosion rates when exposed to bodily fluids. In general, metal erosion or corrosion involves a chemical reaction between a metal surface and its environment. Erosion or corrosion in a wet environment, such as a vascular environment, results in removal of metal atoms from the metal surface. The metal atoms at the surface lose electrons and become actively charged ions that leave the metal to form salts in solution. A bioerodable stent suitable for use as a stent material forms erosion products that do not negatively impact bodily functions. Representative examples of biodegradable metals that may be used to fabricate an implantable medical device may include, but are not limited to, magnesium, zinc, and iron. In one embodiment, a bioerodable metal stent may be completely eroded when exposed to bodily fluids, such as blood, between about a week and about three months, or more narrowly, between about one month and about two months. In general, it may be desirable to manufacture an implantable medical that includes relatively distinct regions that have different erosion profiles when exposed to bodily fluids. In this way the erosion profile of the stent may be customized to various treatments. Various embodiments of an implantable medical device with such erosion profiles may include a metallic region composed of a bioerodable metal and a polymer region composed of a biodegradable polymer. The metallic region may erode at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. In some embodiments, the polymer region may be an outer region or layer of the device and the metallic region may be an inner region or layer of the device. An outer region or layer may refer to a region or layer that is exposed first to a vascular environment. Direct contact or exposure of the inner region or layer to a vascular environment may be inhibited or prevented by an outer region or a region that is closer to the vascular environment. For example, a strut of a stent may include an inner region or core with an outer region or coating that inhibits or prevents direct contact or exposure of the inner region or core to a vascular environment. The metallic region may be configured to provide mechanical support for at least some of the time the device is implanted in a bodily lumen. In certain embodiments, the implantable medical device may include a metallic region that includes a cylindrical or substantially cylindrical cross-sectional pattern of struts. The strut pattern can also be square, rectangular, oval, or another cross-sectional shape. For example, the metallic region may be a cylindrical or substantially cylindrical coil or mesh of metallic wire. In addition, a metallic region may be a pattern of struts formed on a metallic tube by cutting or etching. The polymer region may be a biodegradable polymer coating on the metallic region. In some embodiments, the polymer region may include an active agent. The polymer region may be configured to release the active agent for a selected amount of time. The release may occur through the brake-up of the polymer and/or via migration of the active agent out of the polymer. The selected amount of time may correspond approximately to a desired treatment time of a stent. Additionally, the metallic region may have pores that are configured to include an active agent. For example, the metallic region can be formed by sintering particles, fibers, and wires of material. In some embodiments, the metallic region may erode at a faster rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. In some embodiments, the polymer region may be configured to delay, inhibit, or prevent erosion of the metallic region in a manner that allows the metallic region to provide mechanical support to a bodily lumen. For example, the polymer region may be configured to delay, inhibit, or prevent erosion of the metallic region for a selected time period. The selected time period may be at least a portion of the time period that the metallic region is desired to provide mechanical support. It may be desirable for a metallic region to provide mechanical support for a majority of, all of, or longer than a desired treatment time of the stent. Some embodiments may include a metallic region that is configured to erode when the metallic region is exposed to bodily fluids due to degradation of the polymer region. The metallic region may be exposed to bodily fluids by erosion of the polymer region and/or diffusion of bodily fluids through the polymer region. In some embodiments, a metal region may start to erode when the polymer region is only partially degraded and/or eroded. Partially means less than 50% of the polymer, or alternatively less than 40%, 30%, 20%, 10%, or 5%. In other embodiments, the metal region may start to erode when the polymer region is completely (greater than 99%) degraded and/or eroded or when a majority of the polymer is degraded and/or eroded. Majority includes over 50%, 60%, 70%, 80%, 90%, or alternatively, over 95% of the polymer. In some embodiments, an outer polymer region may be a bulk eroding polymer. Representative examples of bulk eroding polymers include, but are not limited to, poly(L-lactide), poly(glycolide), poly(D,L-lactide), poly(trimethylene carbonate), polycaprolactone, and copolymers thereof. During a treatment time, the polymer degrades resulting in a decrease in the molecular weight of the polymer region and deterioration of mechanical properties. A polymer may be selected that has a relatively low water diffusivity. In some embodiments, the polymer may be capable of absorbing less than about 3% by volume, or more narrowly, less than about 1% of its volume. However, water diffusivity in the polymer increases as the polymer region degrades. The increased diffusivity of water may result in erosion of the metallic region prior to complete erosion of the polymer region. In an embodiment, the metallic region may be configured to completely or almost completely erode before the polymer region is completely eroded. In other embodiments, the polymer region may be configured to completely or almost completely erode before the metallic region is completely eroded. In other embodiments, an outer polymer region may be a surface eroding polymer. Representative examples of surface eroding polymers include, but are not limited to, polyorthoesters, polyanhydrides and copolymers thereof. A surface eroding polymer may be selected that has a water diffusivity that inhibits or prevents erosion of the metallic region for a selected time period. The metallic region may be configured to erode when erosion of the polymer region exposes a portion of the metallic region to bodily fluids. Due to higher water diffusivity in a bulk eroding polymer, it is expected that the erosion of the metallic region will occur later and over a smaller time frame with a surface eroding polymer as an outer region than with a bulk eroding polymer as an outer region. FIG. 4 depicts a schematic illustration of an embodiment of a cross-section of a strut 150 of a stent that includes an outer region 155 and an inner region 160. Outer region 155 is a relatively slow eroding polymer region and inner region 160 is a relatively fast eroding metallic region. FIGS. 5A and 5B illustrate examples of erosion as a function of time for such a stent with an outer biodegradable polymer region and an inner bioerodable metallic inner region. FIG. 5A depicts erosion for a stent with a bulk eroding polymer region and FIG. 5B depicts erosion for a stent with a surface eroding polymer region. In FIG. 5A, a curve 170 represents the total erosion of the polymer region and curve 175 represents the total erosion of the inner metallic region. In FIG. 5B, a curve 180 represents the total erosion of the polymer region a curve 185 represents the total erosion of the metallic region. A time 190 corresponds to an approximate time of implantation of the stent in a vessel. From time 190 to approximately a time 195 in FIG. 5A and between time 190 and approximately time 200 in FIG. 5B, there is minimal erosion of the metallic region. At some time during a time period 205 in FIG. 5A and a time period 210 in FIG. 5B, the stent may be no longer required for treatment. During time periods 205 and 210, the polymer and metallic regions may be completely or almost completely eroded and the metallic regions may no longer provide mechanical support. The erosion of the metallic region rises sharply during time periods 205 and 210 due to degradation and/or erosion of the polymer regions. A comparison of curve 175 to curve 185 illustrates the sharper erosion profile of the metallic region when a surface eroding polymer is used rather than bulk eroding polymer for the polymer region. In certain embodiments, the device may have more desirable properties than a polymer-fabricated device; a biostable or bioerodable metal device; or a polymer-coated biostable metal device. For instance, the device may have a greater radial strength than an equivalent device fabricated from the biodegradable polymer in which the equivalent device has the same structure and dimensions as the device. Dimensions may include the length and radius of a stent and cross-sectional dimensions of struts of the stent. Structure may include the structure of a pattern of a stent. In addition, the device may have greater flexibility than an equivalent device fabricated from the metal in which the equivalent device has the same dimensions and structure as the device. Additionally, the device may include a stent with a smaller profile than an equivalent device fabricated from the biodegradable polymer. An equivalent device is an equivalent stent with the same radial strength and same dimensions and structure as the device. A smaller profile may correspond to thinner struts. Also, the device may have sufficient radio-opacity to be imaged by X-Ray radiation, unlike a polymer-fabricated device. Also, as discussed above, the device may also be capable of completely eroding away when it is no longer required for treatment. In certain embodiments, the metallic region and the polymer region may be configured to have certain desired properties such as erosion rate and mechanical properties. Desired properties may be obtained by forming the polymer region and/or the metallic region from polymers and/or metals, respectively, to obtain the desired properties. The polymer may have a uniform or substantially uniform composition and uniform or substantially uniform properties such as erosion rate and mechanical properties. The polymer region may be a pure or a substantially pure biodegradable polymer. Alternatively, the polymer may be a uniform or substantially uniform mixture of at least two types of polymers. Similarly, the metallic region may have a uniform or substantially, uniform composition and uniform or substantially uniform properties such as erosion rate and mechanical properties. The metal may a pure or substantially pure metal. Also, the metal region may be a uniform or substantially uniform alloy that includes at least two types of metals. In addition, the metal region may be a uniform or substantially uniform mixture that includes at least two types of metals. The properties such as erosion rate may be uniform or substantially uniform. Alternatively, it may be desirable in other embodiments to have a polymer region and/or metallic region that have nonuniform composition with nonuniform properties. In some embodiments, the polymer region may be a nonuniform mixture of at least two types of polymers. Similarly, the metallic region may be a nonuniform mixture of at least two types of metals. In other embodiments, the polymer region may include at least two uniform or substantially uniform layers in which at least two layers have different erosion rates. Different layers may correspond to different pure or substantially pure polymers or polymer mixtures. In some embodiments, one layer may be a bulk eroding polymer and another layer may be a surface eroding polymer. In one embodiment, the surface eroding polymer can be disposed over the bulk eroding polymer. Alternatively, the bulk eroding polymer can be disposed over the surface eroding polymer. In a similar manner, the metallic region may include at least two layers in which at least two layers have different erosion rates. Thus, the erosion and erosion rate may be customized to any number of treatment applications. For example, FIG. 6 depicts a schematic illustration of a cross-section of strut 220. Strut 220 in FIG. 6 may have a polymer region that includes a polymer layer 225, a polymer layer 230, and a metallic region 235. In addition, strut 220 in FIG. 6 may have a metallic region that includes a metallic layer 230, a metallic layer 235, and a polymer region 225. In other embodiments, the properties such as the erosion rate of a stent may be further customized by forming a stent with at least three alternating polymer and metallic regions. In one embodiment, a second metallic region may be formed that contacts the polymer region in which the polymer region is between the metallic region and the second metallic region. Additionally, another embodiment may include forming a second polymer region that contacts the metallic region in which metallic region is between the polymer region and the second polymer region. In some embodiments, one or more of the polymer regions may include an active agent. In other embodiments, one or more of the metallic regions may include an active agent. For example, strut 220 in FIG. 6 may have a polymer region 225, a polymer region 235, and a metallic region 230 between the polymer regions. In addition, strut 220 in FIG. 6 may have a polymer region 230, a metallic region 235, and a metallic region 225. A polymer region may be biostable or biodegradable. Similarly, a metallic region may be biostable or biodegradable. Preferably, one or all of the polymeric regions are biodegradable and one or all of the metallic regions are degradable as well. Further embodiments of incorporating desirable properties into implantable medical devices may include a device that is at least partially composed of a material that is a mixture of a biodegradable polymer and bioerodable metallic material. In some embodiments, an implantable medical device may be composed of a mixture having a biodegradable polymer and bioerodable metallic particles. In an embodiment, a method of manufacturing the device may include mixing a biodegradable polymer and bioerodable metallic particles to form the mixture. In certain embodiments, the biodegradable polymer and the bioerodable metallic particles may be mixed in a mixing apparatus such as an extruder. Certain embodiments may further include mixing a biostable polymer and/or biostable metallic particles with the biodegradable polymer and bioerodable metallic particles. Other embodiments may further include mixing the biodegradable polymer and bioerodable metallic particles with metallic particles that include at least one particle composed of a mixture or alloy of at least of one bioerodable metal and at least one biostable metal. Some embodiments of the method may further include using the mixture to fabricate an implantable medical device or to coat an implantable medical device. In certain embodiments, the metallic particles may be metallic nanoparticles. A “nanoparticle” refers to a particle with a dimension in the range of about 1 nm to about 10,000 nm. A significant advantage of nanoparticles over larger particles is that nanoparticles may form a more uniform mixture in a polymer matrix. A resulting mixture may then have a more uniform improvement of properties such a radial strength and flexibility. Additionally, nanoparticles may be absorbed by bodily fluids such as blood without negative impact to bodily functions. Representative examples of metallic particles may include magnesium, zinc, aluminum, and oxides of such metals. In some embodiments, the mixture may also include an active agent. In other embodiments, the nanoparticles can include an active agent or a drug. The biodegradable polymer may be a pure or substantially pure biodegradable polymer. Alternatively, the biodegradable polymer may be a mixture of at least two types of biodegradable polymers. A metallic particle may be a pure or substantially pure bioerodable metal or bieoerodable metal compound. Alternatively, a metallic particle may be a mixture of at least two types of bioerodable metals or bioerodable metallic compounds. A metallic particle may also be an alloy composed of at least two types of bioerodable metals. The metallic particles may be a mixture of at least two types of metallic particles. In certain embodiments, an implantable medical device manufactured from the mixture including a biodegradable polymer and bioerodable metallic particles may be configured to have desired properties. A desired property may include, but is not limited to, a desired erosion rate, a desired degree of radio-opacity, or desired mechanical performance, for example, a desired radial strength. In some embodiments, desired properties of a device may be obtained by modifying the composition of the mixture of the biodegradable polymer and bioerodable metallic particles. In one embodiment, the composition of the biodegradable polymer may be modified. Differences in erosion rates and/or mechanical performance of different biodegradable polymers may be used to obtain desired properties of the mixture. Similarly, the composition of the mixture may be modified by modifying the composition of the metallic particles. For example, the ratio or concentration of different types of metallic particles in the mixture or the composition of individual particles may be altered to obtain desired properties. In other embodiments, the ratio of polymer to metallic particles or metal may also be modified. Since a polymer and metallic particles may have different erosion rates, the ratio of polymer to metallic particles may be modified to obtain a desired erosion rate. For example, if a bioerodable metal has a faster erosion rate than the biodegradable polymer, decreasing the ratio of polymer to metallic particles may increase the erosion rate of a device. Additionally, the radial strength of a device may be increased by decreasing the ratio of polymer to metallic particles. Several embodiments may include various ways of using the mixture to fabricate or to coat an implantable medical device. In an embodiment, fabricating a device may include forming a tube from the mixture. A tube may be formed from the mixture using an extruder. Alternatively, a planar film or sheet may be formed from the mixture, also through extrusion. A tube may then be formed from the planar film or sheet by rolling and bonding the film or sheet. In an embodiment, a stent pattern of struts, such as the one pictured in FIG. 1, may be formed on the tube. The pattern may be formed by a technique such as laser cutting or chemical etching. Examples of lasers that may be used for cutting stent patterns include, but are not limited to, excimer, CO2, or YAG. In another embodiment, fibers may be formed from the polymer and metallic particle mixture and formed into a stent. In other embodiments, the mixture may be used to coat an implantable medical device with the mixture. The device to be coated may be a polymer-fabricated stent; a metallic stent; or a stent fabricated from polymer and metallic particles. In some embodiments, a stent coated by the mixture may be completely or almost completely bioerodable. The mixture for use as a coating may be composed of a biodegradable polymer and a bioerodable metal. In one embodiment, the substrate stent may be a polymer-fabricated stent composed of a biodegradable polymer. In another embodiment, the substrate stent may be a metallic stent that is composed of a bioerodable metal. Other embodiments may include coating a stent fabricated from a mixture of biodegradable polymer and bioerodable metallic particles. In certain embodiments, a device fabricated or coated with a polymer and metallic particle mixture may have more desirable properties than a polymer-fabricated device, a metallic device, or a polymer-coated metal device. A device fabricated from the mixture of polymer and metallic particles may have greater radial strength and greater flexibility than an equivalent device fabricated from the polymer. An equivalent device is the same dimensions and structure as the device. Moreover, a device manufactured with a polymer and metallic particle mixture may be a stent with a smaller profile than an equivalent stent fabricated from the polymer. A smaller profile may include thinner struts. The equivalent device is an equivalent stent with the same radial strength and the same dimensions and structure as the device. Furthermore, due to the metallic particles, the device may have sufficient radio-opacity to be imaged by X-Ray radiation. In addition, the composition of metallic particles in the mixture may be modified to obtain desired properties of the device. For example, the composition may be modified to obtain a desired degree of radio-opacity and mechanical behavior such as radial strength and/or flexibility. Additionally, cutting stent patterns on polymer parts can be difficult since many polymers absorb little or no energy from laser light emitted by lasers conventionally used for cutting patterns. However, the metallic particles in the polymer and metallic particle mixture may help to overcome this difficulty by increasing the absorption of energy from the laser light. While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications can be made without departing from this invention in its broader aspects. Therefore, the appended claims are to encompass within their scope all such changes and modifications as fall within the true spirit and scope of this invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to polymer and metal composite implantable medical devices, such as stents. 2. Description of the State of the Art This invention relates to radially expandable endoprostheses which are adapted to be implanted in a bodily lumen. An “endoprosthesis” corresponds to an artificial device that is placed inside the body. A “lumen” refers to a cavity of a tubular organ such as a blood vessel. A stent is an example of an endoprosthesis. Stents are generally cylindrically shaped devices which function to hold open and sometimes expand a segment of a blood vessel or other anatomical lumen such as urinary tracts and bile ducts. Stents are often used in the treatment of atherosclerotic stenosis in blood vessels. “Stenosis” refers to a narrowing or constriction of the diameter of a bodily passage or orifice. In such treatments, stents reinforce body vessels and prevent restenosis following angioplasty in the vascular system. “Restenosis” refers to the reoccurrence of stenosis in a blood vessel or heart valve after it has been treated (as by balloon angioplasty or valvuloplasty) with apparent success. Stents have been made of many materials including metals and polymers. Polymer materials include both biostable and biodegradable polymer materials. Metallic stents are typically formed from biostable metals. However, bioerodable metal stents have been described. U.S. Pat. No. 6,287,332 B1 to Bolz et al., U.S. Pat. Appl. Pub. No. 2002/0004060 A1 to Heublein et. al. The cylindrical structure of stents is typically composed of a scaffolding that includes a pattern or network of interconnecting structural elements or struts. The scaffolding can be formed from wires, tubes, or planar films or sheets of material rolled into a cylindrical shape. In addition, a medicated stent may be fabricated by coating the surface of either a metallic or polymeric scaffolding with a polymeric carrier. The polymeric carrier can include an active agent or drug. Furthermore, the pattern that makes up the stent allows the stent to be radially expandable and longitudinally flexible. Longitudinal flexibility facilitates delivery of the stent and radial rigidity is needed to hold open a bodily lumen. The pattern should be designed to maintain the longitudinal flexibility and radial rigidity required of the stent. A number of techniques have been suggested for the fabrication of stents from tubes and planar films or sheets. One such technique involves laser cutting or etching a pattern onto a material. A pattern may be formed on a planar film or sheet of a material which is then rolled into a tube. Alternatively, a desired pattern may be formed directly onto a tube. Other techniques involve forming a desired pattern into a sheet or a tube via chemical etching or electrical discharge machining. Laser cutting of stents has been described in a number of publications including U.S. Pat. No. 5,780,807 to Saunders, U.S. Pat. No. 5,922,005 to Richter and U.S. Pat. No. 5,906,759 to Richter. The first step in treatment of a diseased site with a stent is locating a region that may require treatment such as a suspected lesion in a vessel, typically by obtaining an X-Ray image of the vessel. To obtain an image, a contrast agent which contains a radio-opaque substance such as iodine is injected into a vessel. Radio-opaque refers to the ability of a substance to absorb X-Rays. The X-ray image depicts a profile of the vessel from which a physican can identify a potential treatment region. The treatment then involves both delivery and deployment of the stent. “Delivery” refers to introducing and transporting the stent through a bodily lumen to a region in a vessel that requires treatment. “Deployment” corresponds to the expanding of the stent within the lumen at the treatment region. Delivery and deployment of a stent are accomplished by positioning the stent about one end of a catheter, inserting the end of the catheter through the skin into a bodily lumen, advancing the catheter in the bodily lumen to a desired treatment location, expanding the stent at the treatment location, and removing the catheter from the lumen. In the case of a balloon expandable stent, the stent is mounted about a balloon disposed on the catheter. Mounting the stent typically involved compressing or crimping the stent onto the balloon. The stent is then expanded by inflating the balloon. The balloon may then be deflated and the catheter withdrawn. In the case of a self-expanding stent, the stent may secured to the catheter via a retractable sheath or a sock. When the stent is in a desired bodily location, the sheath may be withdrawn allowing the stent to self-expand. The stent may be visualized during delivery and deployment using X-Ray imaging if it contains radio-opaque materials. By looking at the position of stent with respect to the treatment region, the stent may be advanced with the catheter to a location. After implantation of the stent additional contrast agent may be injected to obtain an image of the treated vessel. There are several desirable properties for a stent to have that greatly facilitate the delivery, deployment, and treatment of a diseased vessel. Longitudinal flexibility is important for successful delivery of the stent. In addition, radial strength is vital for holding open a vessel. Also, as the profile of a stent decreases, the easier is its delivery, and the smaller the disruption of blood flow. Additionally, in order to visualize a stent during deployment it is also important for a stent to include at least some radio-opaque materials. Furthermore, it is also desirable for a stent to be bioeroable. Many treatments utilizing stents require the presence of a stent in the vessel for between about six and twelve months. Stents fabricated from biodegradable polymers may be configured to completely erode after the clinical need for them has ended. Although current biodegradable polymer-fabricated stents, biostable metal stents, bierodable metal stents, and polymer-coated metal stents each have certain advantages, they also possess potential shortcomings. Biodegradable polymer-fabricated stents may be configured to degrade after they are no longer needed and also possess a desired degree of flexibility. However, in order to have adequate mechanical strength, such stents require significantly thicker struts than a metallic stent, which results in a larger profile. Inadequete radial strength may contribute to relatively high incidence of recoil of polymer stents after implantation into vessels. In addition, biodegradable polymers, unlike metals, are not radio-opaque which makes visualization of a stent difficult during delivery and after deployment. Moreover, although biostable metallic stents possess favorable mechanical properties, are radio-opaque, and have smaller profiles than polymer-fabricated stents, they are not bioerodable. Bioerodable metallic stents tend to erode too fast, resulting in complete or nearly complete bioerosion before the end of a treatment time. Therefore, there is a present need for stents that possess more of the favorable properties of polymers and metals.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to implantable medical devices, such as stents, and methods of manufacturing such devices that include a metallic region composed of a bioerodable metal and a polymer region composed of a biodegradable polymer contacting the metallic region. The metallic region may erode at a different rate when exposed to bodily fluids than the polymer region when exposed to bodily fluids. In certain embodiments, the polymer region is an outer layer and the metallic region is an inner layer of the device. In some embodiments, the metallic region erodes at a faster rate than the polymer region when exposed to bodily fluids. Further aspects of the invention are directed to implantable medical devices and methods of manufacturing such devices that include a mixture of a biodegradable polymer and bioerodable metallic particles. In some embodiments, the metallic particles are metallic nanoparticles. In some embodiments, the mixture may be used to coat an implantable medical device. In other embodiments, an implantable medical device may be fabricated from the mixture.
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20040628
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20120508
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20050922
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66184.0
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OU, JING RUI
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POLYMER AND METAL COMPOSITE IMPLANTABLE MEDICAL DEVICES
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UNDISCOUNTED
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CONT-ACCEPTED
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10,880,027
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ACCEPTED
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Apparatus, and associated method, for communicating packet data in a network including a radio-link
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Apparatus, and associated method, for improving packet data communications upon a communication path including a radio-link. Determination is made of the conditions on the radio-link when selecting the optimal size of a transmission window within which to transmit packets of data. And, retransmission time-out values are also selected responsive to the indications of the radio-link conditions.
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1. In a communication system in which packet data is communicated between a first host and a second host upon a communication path, the communication path including a radio-link, an improvement of apparatus for selecting a window size within which to transmit a data packet, said apparatus comprising: a radio-link status determiner coupled to receive an indication of the radio-link forming a portion of the communication path between the first host and the second host, said radio-link status determiner for determining an indication of a characteristic of the radio-link and for generating a radio-link status indication indicative of the indication of the characteristic determined thereat; and a window size selector coupled to receive the radio-link status indication generated by said radio-link status determiner, said window size selector for selecting a window size within which to transmit the data packet. 2. The apparatus of claim 1 wherein the indication of the radio-link to which said radio-link status determiner is coupled to receive comprise indications of a packet data throughput rate upon the radio-link. 3. The apparatus of claim 2 wherein the radio-link includes a forward link and a reverse link and wherein the indication of the packet data throughput rate is of at least a selected one of the forward link and the reverse link. 4. The apparatus of claim 3 wherein the indications of the radio-link to which said radio-link status determiner is coupled to receive comprises indications of a RTT (round-trip-time) representative of a time period within which two-way transmission with the first host are determined to be effectuated. 5. The apparatus of claim 4 wherein the communication system is defined by logical layers, the logical layers including an RLC (radio-link control) layer, and wherein the time period of which the RTT is representative corresponds to a round-trip time of communication of a data packet and an acknowledgment thereto less retransmission times at the RLC layer. 6. The apparatus of claim 4 wherein the optimal window size selected by said optimal window size selector is proportional to the indication of the data through put rate and to the RTT. 7. The apparatus of claim 1 wherein the first host comprises a mobile host and the second host comprises a network host and wherein the mobile host is further operable to send a message to the network host, wherein the message includes an offered window field, and wherein a value representative of the optimal window size selected by said optimal window size selector is inserted into the offered window field. 8. The apparatus of claim 7 wherein the network host is operable to receive the message, including the value representative of optimal window size, sent by the mobile host, and to transmit the data packet, the data packet transmitted by the network host within a transmission window of a maximum size corresponding to the optimal window size. 9. The apparatus of claim 1 wherein the first host further comprises a retransmission timer at least for selecting when to retransmit a data packet and wherein said radio-link status determiner is further for determining an indication of a characteristic of the radio-link forming a portion of the communication path and for generating a radio-link quality status indication indicative of the indication of the characteristic determined thereat, a value representative of which is applied to the retransmission timer and responsive to which a time-out value of the retransmission timer is selected. 10. The apparatus of claim 9 wherein the radio-link status indication generated by said radio-link status determiner is representative of changes in the radio-link status between a first selected time and at least a second selected time. 11. The apparatus of claim 10 wherein, if the radio-link status indication is beyond a selected value, the time-out value of the retransmission timer is caused to be increased. 12. The apparatus of claim 11 wherein the communication system is defined by logical layers, the logical layers including an L3CE layer, and wherein the radio-link status indication comprises a RTT (round-trip-time) representative of a time period within which two-way transmissions with the first host at the L3CE layer are determined to be effectuated. 13. The apparatus of claim 12 wherein the time-out value of the retransmission timer is caused to be increased if changes in values of the RTT exceed a multiple of a mean deviation. 14. The apparatus of claim 12 wherein the time-out value of the retransmission timer is caused to be increased if more than a selected number of data packets are communicated upon the communication path without acknowledgment thereto. 15. The apparatus of claim 12 wherein the time-out value of the retransmission timer is caused to be increased during transmission of a selected number of data packets subsequently to be transmitted. 16. The apparatus of claim 1 wherein the first host and the second host are operable to communicate data packets pursuant to a TCP (transmission control protocol) protocol and wherein said radio-link status determiner determines the indication of the throughput quality of TCP-formatted data packets. 17. In a communication system in which packet data is communicated between a first host and a second host upon a communication path, the communication path including a radio-link, and the mobile host having a retransmission timer at least for selecting when to retransmit a data packet, an improvement of apparatus for the first host for selecting a window size within which to transmit the data packet, said apparatus comprising: a radio-link status determiner coupled to receive indications of the radio-link forming a portion of the communication path between the first host and the second host, said radio-link status determiner for determining an indication of a characteristic of the radio-link and for generating a radio-link quality indication indicative of the indication of the characteristic determined thereat; and a retransmission timer time-out value selector coupled to receive a value representative of the radio-link status indication generated by said radio-link status determiner, said retransmission timer time-out value selector for selecting a time-out value of the retransmission timer responsive to the value representative of the radio-link status indicators. 18. In a method for communicating packet data between a first host and a second host, the first host and the second host connected together by way of a communication path which includes a radio-link, an improvement of a method for the first host for selecting a window size within which to transmit a data packet, said method comprising: determining an indication of throughput on the radio-link; generating a radio-link status indication indicative of the throughput determined during said operation of determining; and selecting a window size within which to transmit the data packet responsive to a value of the radio-link status indication. 19. The method of claim 18 wherein the first host further comprises a retransmission timer at least for selecting when to retransmit a data packet and wherein said method further comprises the operations of: determining an indication of radio-link status of the radio-link forming a portion of the communication path; generating a radio-link status indication indicative of the indication of the radio-link status determined during said operation of determining; and adjusting a time-out value of the retransmission timer if the radio-link status indication is beyond a selected threshold. 20. The method of claim 19 wherein the radio-link status indication determined during said operation of determining the indication of radio-link status is representative of changes in the radio-link status. 21-22. (Canceled)
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CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation of U.S. patent application Ser. No. 09/585,203, filed on 1 Jun. 2000. The present invention relates generally to the communication of packet data, such as TCP-formatted data, in a communication system which includes a radio-link, such as a UMTS (universal mobile telephone service) wireless data network. More particularly, the present invention relates to apparatus, and an associated method, by which, more optimally to communicate data packets in the UMTS, or other, communication system. BACKGROUND OF THE INVENTION Advancements in communication technologies have permitted the introduction of, and popularization of, new types of communication systems. As a result of such advancements, significant increases in the rates of data transmission, have been permitted. And, new types of communication services have also been made possible. A radio communication system is exemplary of a type of communication system which has benefited from advancements in communication technologies. At least a portion of a communication path utilized in a radio communication system includes a radio-link. A radio communication system inherently increases communication mobility as communication channels defined in such a system are formed of radio channels and do not require wireline connections for their formation. Advancements in digital communication techniques are amongst the advancements in communication technologies which have permitted the introduction of the new types of communication systems. Communications effectuated through the use of digital communication techniques are generally of improved bandwidth efficiencies in comparison to communications effectuated utilizing conventional, analog techniques. A packet data communication system is also exemplary of a communication system made possible as a result of advancements in communication technologies. In a packet communication system, groups of digital bits are formatted into packets to form packets of data. The packets of data are communicated, either individually, or in groups, at discrete intervals. Once received, the packets of data are concatenated together to recreate the informational content of the digital bits of which the packets are formed. Because packets of data can be communicated at discrete intervals, the communication channel upon which the packets are transmitted need not be dedicated to a single communication pair. Instead, a shared communication channel can be used by a plurality of communication pairs to communicate packets of data on the shared channel. Standardized protocols by which to format and to communicate packets of data have been developed. A TCP/IP (transmission control protocol/ Internet protocol) is exemplary of a packet formatting scheme. And, an X.25 protocol describes another exemplary protocol scheme. Standards relating to conventional packet communication systems have been promulgated for both conventional wireline, as well as wireless, systems. Packet radio services have been proposed, for instance, for several different cellular communication systems. A cellular communication system is a type of radio communication system, widely implemented and popularly-used. Exemplary of such a packet radio service is the GPRS (General Packet Radio Service) system for GSM (Global System for Mobile Communications). One proposal is for a so-called 3G (third generation) cellular communication system, referred to as a UMTS (universal mobile telecommunications system) network. Packet data communications are provided for therein. In this proposed system, as well as others, packet data is communicated between a mobile host and a network host. A communication path formed between the mobile and network hosts includes at least one radio-link formed between the mobile host and infrastructure of the UMTS network. Proposals related to the UMTS network include the use of TCP/IP protocols for end-to-end communications, viz., for communications over the wireless and also the fixed parts of the UMTS network. Such a service is typically a “best effort” service, i.e., a service without a guaranteed quality of service. The infrastructure of the UMTS network includes both a wireline IP-based UMTS core network and a radio part, i.e., a radio-link, formed between the mobile host and a base station, forming a portion of the UMTS core network. TCP-based protocols have, however, conventionally been designed for conventional, wireline networks. In conventional TCP protocols, measures intended to control the flow of data and possible congestion within the communication network are designed according to the characteristics of wireline networks where packet losses are often the result of congestion. Congestion arises, for instance, because of the aforementioned sharing of communication resources for different communication pairs. When a packet communication system is implemented in wireless form, however, packet losses are often due to bit errors and/or packet losses introduced during transmission on a radio-link. Because a UMTS network includes both a wireline, core network and also a radio part, packet losses occurring at the radio part, such as due to communication handovers or corruption on the radio-link are retransmitted locally. When the UMTS is defined in terms of logical layers, local retransmission means, for example, that data packets are retransmitted over the radio link by a radio-link control (RLC) layer. These local retransmissions decrease end-to-end throughput between the mobile and network hosts due to the time required to effectuate the local retransmissions. If a conventional TCP protocol is used in connection with a data transmission network, such as a UMTS network, implemented at least in part over a radio communication link, a sending station originating TCP data continues sending packet data at a constant rate, irrespective of the local retransmissions at the radio part of the network. Thus, the possibility for congestion of the UMTS core network increases, as new packets are transmitted from the network host in the fixed line part of the network while earlier packets are still undergoing retransmission over the radio link to recover from losses in the radio-link. Deleterious results, such as spurious time-outs of the sending station, can occur, significantly reducing the end-to-end performance of the network. Spurious time-outs occur because of the additional time taken to receive acknowledgments for data packets that are retransmitted over the radio-link under local control of a radio link control layer (RLC). If data packets are retransmitted by the radio link control layer, additional time elapses before the sending TCP protocol in the mobile host receives an acknowledgment that a particular packet has been received by the receiving host e.g. in the fixed line part of the network. By the time an acknowledgment is received, the TCP,retransmission timer in the mobile host may have already expired and conventional congestion control measures may have been initiated by the sending TCP, resulting in decreased data throughput. Furthermore, in this situation, initiation of conventional congestion control mechanisms is erroneous because the delayed acknowledgment was due to the additional time required for retransmission over the radio link, rather than real congestion in the network. According to the invention, this erroneous initiation of TCP congestion control measures is prevented by increasing TCP timer time-out values in conditions where there is an increased likelihood of retransmission over the radio link, for example in situations where there is degradation in the quality of the radio-link or a decrease in the bandwidth available for communication over the radio link. On the other hand, if true congestion of the communication network occurs, the method according to the invention still allows conventional congestion control measures to be initiated. If a manner could be provided by which better to effectuate packet data transmission by a sending station to take into account the performance of the radio part of the system, improved system operation would result. QoS (Quality of Service) levels are also proposed to be defined in the UMTS network. The QoS levels define, in general, performance parameters pursuant to which a particular communication service is to be effectuated. Several communication services are non-real-time services, such as communications with the WWW (World Wide Web), TELNET™, e-mail services, etc. Applications to effectuate such services, logically, run on top of a TCP logical layer. And, such communication services typically are implemented at QoS levels referred to as“best-effort” traffic classes. Such traffic classes do not give guarantees of available bandwidth and, hence, delivery times. Conversely, communication services which are of a real-time nature typically are implemented at higher QoS levels and such communication services are effectuated with a higher priority than non-real-time TCP-related services. Because of the lower priority levels of the TCP-related, non-real-time services, the bandwidth available to effectuate such services is susceptible to rapid change. Conventional manners by which to effectuate TCP flow control do not include a manner by which to set transmission rates according to such rapid changes. In conventional TCP implementations, a standard mechanism, referred to as self-clocking behavior is used to limit the transmission rate of a sending station. Self-clocking behavior refers to a manner by which the sending station is able to send a new packet, responsive to reception of an acknowledgment of an earlier-transmitted packet, if the size of the transmission window remains constant. In conventional TCP operation, however, the transmission window is not constant. Instead, the transmission window is of a size which is adjusted regularly, according to the arrival of acknowledgments and occurrence of retransmission time-outs. In practice, then, in standard operation, a sending station increases a transmission window size until some point in a communication path, such as the radio access node (RAN). Thereafter, congestion control mechanisms are implemented, but such implementations abruptly slow down transmission rates of communications. This behavior also results in reduced end-to-end throughput rates. If a manner could be provided by which better to effectuate communication of packet data by taking into better account changes of bandwidth availabilities for the communication of the packet data, improved system operation would further result. It is in light of this background information related to packet data communications that the significant improvements of the present invention have evolved. SUMMARY OF THE INVENTION The present invention, accordingly, advantageously provides apparatus and an associated method, by which more optimally to communicate data packets in a packet communication system, such as a UMTS (Universal Mobile Telecommunications System) wireless data network. Operation of an embodiment of the present invention better optimizes the size of a transmission window within which a sending station sends a packet of data. By better selecting the size of the transmission window, the throughput rates of data communication of the packet data is improved. Operation of a further, or alternate, embodiment of the present invention provides a manner by which to adjust a retransmission timer responsive to changes in the characteristics of a radio-link upon which data packets are communicated. The timer is adjusted in a manner to reduce the occurrence of spurious retransmissions as a result of changing radio-link conditions. In one aspect of the present invention, apparatus is provided for a mobile station, herein referred to as a mobile host, by which to select an optimal transmission window within which a data packet is to be transmitted thereto by a network host. Determination is made at the mobile host of the optimal size of the transmission window responsive to determination of throughput rates, or other link status indication related to the radio-link. Responsive to the measured, or otherwise determined, indication, selection is made of the optimal transmission window size. A value respective of the optimal transmission window size is then sent to the network host. The optimal transmission window size is used by the network host as a maximum size of the transmission window within which the network host thereafter transmits a data packet. In another aspect of the present invention, apparatus is provided for a mobile host to select a time-out value for a retransmission timer of the mobile host. Measurement, or other determination, of a radio-link quality indication is made. Responsive to a value of the radio-link quality being beyond a threshold value, the timer's time out value is adjusted. In one implementation, the radio link quality indication is representative of changes in communication quality levels. For example, if a significant deterioration in the quality of the radio link is indicated, the time-out of the retransmission timer is increased. In a packet data communications network implemented at least in part over a radio link, time-out values which are too low can cause spurious time-outs. This happens because of the additional time taken to perform retransmission over the radio link, under the control of a radio link control layer, for example. As previously explained, this results in decreased throughput as congestion control procedures are started, but performance of such procedures is in vain. In a situation in which real congestion of the core network exists, the mobile host does not use an excessively large window. In one implementation, improved TCP flow control is provided for a mobile host operable in an IP network. Improved throughput rates are made possible by determinations made at the mobile host of indications related to the TCP communications upon a radio link forming a portion of the communication path between the mobile host and a network host (or any sending TCP station). Link layer status information at a radio link control layer which specifically provides information about the radio-link is used to optimize communications. Throughput and link status data is used to set an optimal TCP offered window size. And, such data is also used to improve the ability of the retransmission timers of the mobile host to react to changes in the link status or in available bandwidth. In one embodiment, all necessary determinations and selections required for operation of the embodiment of the present invention are effectuated at the mobile host. In a further implementation, apparatus is provided for a UMTS mobile terminal to optimize better TCP protocols to account for flow and congestion characteristics of wireless communication links. In contrast to conventional TCP flow and congestion control measures, which are specifically designed for fixed networks, operation of an embodiment of the present invention takes into account radio-link characteristics to optimize TCP transmission parameters. Data throughput and radio-link status indications, e.g., from a UMTS protocol stack, are used to set an optimal TCP window size. And, the data throughput and radio-link status indications are also used to improve the ability of TCP retransmission timers of the mobile terminal to react to changes in the link status or in available bandwidth. Implementation of the various embodiments of the present invention can be effectuated entirely at the mobile terminal, thus requiring no changes to fixed network elements, such as IP routers or network terminals. In these and other aspects, therefore, apparatus, and an associated method, is provided for a first host operable in a communication system in which packet data is communicated between the first host and a second host upon a communication path in which the communication path includes a radio-link. The apparatus, and associated method, selects an optimal window size within which to transmit a data packet. A radio-link status determiner is coupled to receive indications of the radio-link forming a portion of the communication path between the first host and the second host. The radio-link status determiner determines an indication of a characteristic of the radio-link. The radio-link status determiner also generates a radio-link status indication indicative of the indication of the characteristic determined thereat. An optimal window size selector is coupled to receive the radio-link status indication generated by the radio-link status determiner. The optimal window size selector selects an optimal window size within which to transmit the data packet. In these and other aspects, apparatus, and an associated method, are also provided for a communication system in which packet data is communicated between a first host and a second host upon a communication path. The communication path includes a radio-link, and the first host has a retransmission timer at least for selecting when to retransmit the data packet. Selection is made of a time-out value of a retransmission timer. A radio-link status determiner is coupled to receive indications of the radio-link forming a portion of the communication path between the first host and the second host. The radio-link status determiner determines an indication of radio-link quality of the radio-link. The radio-link status determiner also generates a radio-link quality indication indicative of the indication of the radio-link quality determined thereat. A retransmission timer time-out value selector is coupled to receive a value representative of the radio-link quality indication generated by the radio-link status determiner. The retransmission timer time-out value selector selects a time-out value of the retransmission timer. Selection is made responsive to the value representative of the radio-link quality indication. A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings, which are briefly summarized below, the following description of the presently-preferred embodiments of the invention, and the appended claims: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a functional block diagram of a packet communication system including a mobile host operable pursuant to an embodiment of the present invention. FIG. 2A and 2B illustrate logical layer diagrams illustrating the logical layers of the control and user planes, respectively, of the packet communication system shown in FIG. 1. FIG. 3 illustrates a functional representation of a flow diagram representative of an embodiment of the present invention. FIG. 4 illustrates a functional representation of a flow diagram representative of another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, a packet communication system, shown generally at 10, provides for the communication of packet data between a sending station and a receiving station. For purposes of illustration and to describe operation of an embodiment of the present invention, a network host 12 and a mobile host 14 form stations between which packet data is communicated. While the network host 12, in the exemplary illustration of the Figure, is a wireline device, implementation of the network host as a mobile device could alternately be represented. And, while the exemplary implementation shall be described with respect to a network in which the TCP (Transmission Control Protocol) is employed and TCP/IP-formatted data packets are communicated between the network and mobile hosts 12 and 14, other systems can analogously be represented. Control of when a data packet is transmitted is effectuated during operation of an embodiment of the present invention by taking into account characteristics of a radio-link which forms a portion of a communication path extending between the network and mobile hosts. The communication system 10 includes network infrastructure, here shown to be formed of an IP-based wireline UMTS (Universal Mobile GPRS Telecommunications System) core network, including a 3G-GGSN (3G-GPRS Support Node) 16. The 3G-GGSN 16 is coupled to the network host 12 by way of a packet data network (PDN) 18. The 3G-GGSN is further coupled to a 3G-SGSN (3G Serving GPR5 Support Node) 22. And, the 3G-SGSN is coupled to a radio base station 24. A communication path, here of a wireline nature, extends between the network host and the base station 24 by way of the packet data network, the 3G-GGSN 16, and the 3G-SGSN 22. A radio-link 26 having both “forward” or “down” link 28 and a “reverse” or “up” link 32 couples the mobile host 14 with the base station 24. The radio-link 26 also forms a portion of the communication path extending between the network and mobile hosts 12 and 14. Other logical structure of the network infrastructure of the system, such as location registers and other nodes are not shown for purposes of simplicity. The illustrated portions of the communication system, however, illustrate the communication path formed between the network and mobile hosts to include both a wireline core network and a radio part. Operation of an embodiment of the present invention takes into account the character of the radio-link in controlling flow characteristics of data packets between the network and mobile hosts and also the properties of the fixed line part. In the event of congestion within the fixed-line IP network, normal TCP retransmission is effectuated. The mobile host 14 includes both a receiver portion 42 and a transmitter portion 44. The receiver portion 42 is operable to act upon data packets received at the mobile host. The transmitter portion 44 is operable to transmit acknowledgments to acknowledge receipt at the mobile host of data packets communicated to the mobile host and also to transmit data packets generated by the mobile host. The mobile host further includes a controller 48 operable to control operation of the receiver and transmitter portions of the mobile host. The controller includes functional elements of an embodiment of the present invention to select an optimal transmission window size within which the network host communicates data packets to the mobile host. A retransmission timer 52 functionally represents a timer used to time the transmission of data during communication of packet data in the communication system 10. The controller further includes a radio-link characteristic detector 54, here coupled to the receiver portion to receive indications of communication characteristics of the radio-link. The radio-link characteristic detector is operable to determine characteristics of the radio-link therefrom. The controller further includes a flow monitor 56 for monitoring data throughput flows, either on the downlink or uplink paths. The controller also includes an OWND (Optimal Window) calculator 62 coupled to receive indications of determinations made by the radio-link characteristic detector 54. The OWND calculator is operable to calculate an optimal transmission window size for a transmission window within which data packets are to be communicated by the network host to the mobile host. And, the controller further includes a retransmission timer time-out value selector 64, also coupled to the radio-link characteristic detector 54. The retransmission time-out value selector is further coupled to the retransmission timer 52 and is operable to select the time-out value pursuant to which the retransmission timer is operable. During operation of an embodiment of the present invention, packet data generated by the network host 12 is communicated by way of the communication path to the mobile host 14. Messages communicated to the mobile host include an offered window value, shown at 66, forming a portion of a message communicated to the mobile host. The offered window field is a field of a standard TCP header. In the exemplary implementation, the contents of the offered window field 72 sent from the mobile host to the network host are affected. The flow monitor 56 is operable to provide an indication of data flow rate to the OWND calculator 62. In one implementation, the OWND calculator calculates an optimal window size responsive to the data throughput rates detected by the flow monitor 56. In a further implementation, the OWND calculator is further operable responsive to detections made by the radio-link characteristic detector 54 in the determination of the optimal transmission window size. Values representative of the calculations performed by the calculator 62 are provided to the transmitter portion 44 which formats the values into an offered window field 72 of a message communicated by the mobile host to the network host. When received by the network host, the value contained in the offered window field 72 forms a maximum transmission window size within which the network host subsequently transmits data packets to the mobile host. The mobile host itself may also adopt the same maximum window size for its own transmissions of packet data to the network host. During operation of a further embodiment of the present invention, responsive to detections made by the radio-link characteristic detector 54, the retransmission time-out value selector 64 is selectively operable to alter operation of the retransmission timer 52. In the event that a significant change in the radio-link characteristics is detected, the time-out value of the retransmission timer is adjusted. When deterioration of the quality of the radio-link in excess of a selected amount is detected, the retransmission timers are prolonged thereby to avoid spurious retransmission due to deterioration of radio-link conditions. Advantageously, the transmission timers of packets that have already been transmitted (but not acknowledged) are prolonged, as are the timers for subsequently transmitted packets. Turning next to FIGS. 2A and 2B, the communication system 10, shown previously in FIG. 1, is again shown, here in logical layer form. The logical layers of the mobile host 14 are illustrated at the left-most portion of the Figure (as shown) and, the network portion of the communication system is illustrated at the right-most (as shown) portion of the Figure. FIG. 2A illustrates the control plane protocols and FIG. 2B illustrates the user plane protocols of the communication system. The logical layers are exemplary of the logical construction proposed for the UMTS system. Other systems can analogously be represented. In the control plane protocol representation shown in FIG. 2A, the mobile host (MS) 14 is shown to include CC (call control) and SM (session management) layers 76 and 78 which reside upon an MM (mobility management) layer 80. The MM layer resides upon an RRC (radio resource control) layer 82 which, in turn, resides upon an RLC-C (radio link control) layer 84. The layer 84 resides upon the MAC (medium access control) layer 86 which resides upon the WCDMA (wideband code division multiple access) L1 layer 88. A radio-link indicated by Uu is formed between the mobile host 14 and the radio base station 24. The base station is shown to include a BS-RRC (radio resource control) layer 90 and BSAP (base station application part) layer 92. The BS-RRC layer 90 resides upon the MAC layer 94 which, in turn, resides upon the WCDMA L1 layer 96. And, the BSAP layer 92 is shown to reside upon the transport layer 98. The network also includes an RNC (radio network controlloer) 102, here shown to include an RRC layer 104 and an RANAP (radio access node application part) layer 106. The RRC layer 104 resides upon the RLC-C layer 106, which in turn, resides upon the BSAP and MAC layers 108 and 110 respectively. The layers 108 and 110, in turn, reside upon transport layers 112. And, the RANAP layer 106 resides upon transport layers 114. The network further is shown to include a CN (core network) 116, here shown to include CC and SM layers 118 and 120, corresponding to the layers 76 and 78 of the mobile host. The layers 118 and 120 reside upon the MM layer 122 which, in turn, resides upon the RANAP layer 124. And, the RANAP layer 124 resides upon transport layers 126. In the user plane representation of FIG. 2B, the mobile host 14 is shown to include an L3CE (layer 3 compatibility) layer 128, alternatively known as a PDCP (packet data convergence protocol layer) residing upon an RLC layer 130 which, in turn, resides upon the MAC layer 132. The MAC layer resides upon a WCDMA/TD/CDMA layer 134. A radio link, represented by Uu, is formed between the mobile host 14 and an RAN (radio access node) 136. The RAN 136 is shown to include L3CE and GTP (GPRS tunnelling protocol) layers 138 and 140. The layer 138 resides upon an RLC layer 142 which, in turn, resides upon an MAC layer 144. The layer 144 resides upon the WCDMA/TD/CDMA layer 146. And, the GTP layer 140 resides upon the UDP/TCP (user datagram protocol/transport control protocol) layer 148. Layer 148 resides upon an IP (internet protocol) layer 150 which, in turn, resides upon a second-level layer L2, 152, and an L1 layer 154. The network here further shows the logical layers of the 3G-SGSN 22. The node 22 is here shown to include GTP layers 156 and 158. The layer 156 resides upon a UDP/TCP layer 160 which, in turn, resides upon an IP layer 162. The IP layer resides upon an L2 layer 164 and, in turn, upon an L1 layer 166. Analogously, the GTP layer 158 resides upon a UDP/TCP layer 168, which, in turn, resides upon the IP layer 170. The IP layer 170 resides upon an L2 layer 172 and, in turn, upon an L1 layer 174. FIG. 2B further shows the 3G-SGSN gateway node 16. Here, the node 16 is shown to include a GTP layer 176 which resides upon a UDP/TCP layer 178. The layer 178 resides upon an IP layer 180 which, in turn, resides upon an L2 layer 182, and in turn, upon an L1 layer 184. It should be noted that, in operation of an embodiment of the present invention, the end-to-end TCP layer is modified rather than the TCP/UDP layer of the core UMTS layer. Link layer status information is utilized, as noted above, better to optimize packet data communication using TCP. In a first embodiment of the present invention, throughput and link status data available from the UMTS protocol stack, i.e., the layering of data protocols as illustrated in FIGS. 2A-B, is used to set an optimal TCP offered window size. The mobile host 14 forms a TCP host. During operation of this embodiment, the mobile host is enabled to limit the packet transmission rate of the network host 12 responsive to determinations of the throughput at the radio-link which forms a portion of the communication path between the mobile host 14 and the network host 12. Determination of throughput is conducted on the basis of information obtained from the RLC layers and/or L3CE layers, as appropriate. Control is effectuated over data transmission by the network host 12 to the mobile host 14. Of course, any layer providing such information could be used in theory. More particularly, the optimal size of a TCP transmission window is selected at the mobile host according to radio-link status information. The selected optimal size, the OWND, is indicated in the offered window field, also known as the advertised window field, in TCP acknowledgments which are returned to the network host. The network host utilizes the OWND to define a maximum size of a transmission window within which to transmit a subsequent data packet. Unnecessary congestion and packet losses are avoided as the OWND is chosen according to the wireless link, typically the slowest link in the communication path formed between the network host and mobile host. The OWND is defined at the mobile host according to information at a UMTS data flow monitor, or QoS (quality of service) monitor. While not separately shown in FIGS. 2A and 2B, the monitor is also part of the data protocol stack and is able to give information about the condition of the UMTS network to applications running in the system. Selection of the OWND is, in one implementation, further responsive to an estimation of the radio-link status. The status of the radio link is estimated by measuring round trip-times (RTTs). The term RTT refers in general to the time interval between sending a data packet and receiving an acknowledgment to the sending of the packet. In an embodiment of the present invention, the round trip time RTTL3CE associated with sending a data packet between the L3CE layers of the mobile host and the radio access network is measured. When radio-link quality deteriorates, or available bandwidth in the radio network decreases, this time period typically increases. Thus, changes in RTTL3CE can be used to estimate the amount of time used in performing retransmissions over the radio-link. In the event that the L3CE layer does not provide acknowledgments and RTTL3CE cannot therefore be measured, the RLC RTT (RTTRLC), or another suitable round trip time can be utilized instead. The TCP layer at the mobile host also collects user data throughput information provided by a UMTS flow monitor. The receiving TCP layer further utilizes a conventional, standardized mechanism to estimate the overall end-to-end round trip time at the TCP layer. Thus, according to an embodiment of the invention, the TCP layer transmission rate of the network host is limited responsive to the radio-link status. The rate is limited responsive to calculations of an optimal window size, OWND, at the mobile host by utilizing data throughput information, information related to the time consumed by retransmissions over the radio link estimated by a L3CE-RTT monitor, and RTTs that the TCP layer estimates. The calculated OWND is inserted into the offered window field of TCP acknowledgments sent from the mobile host back to the network host. In the exemplary implementation, calculations are performed at the mobile host and actual limiting of the data transfer rate is performed at the network host. In other implementations, operation in other manners can be effectuated. In normal operating conditions, e.g., including operating conditions in which throughput in the radio-link is well matched to that required by the fixed TCP/IP network, retransmission according to the standard TCP retransmission protocol maintains protection against packet losses due to congestion in the fixed part of the network. According to the invention, when a significant change in data throughput is detected, an algorithm is executed according to an exemplary embodiment (at the mobile host) to estimate a new value of the OWND. Alternatively, the OWND is regularly calculated and added to an offered window field. An equation utilized by which to estimate the OWND is as follows: ownd=Throughput*RTT (1) wherein: OWND is the optimal window size of a transmission window, as calculated at the mobile host; throughput is the measured data flow rate; and RTT is a round-trip-time, as defined below. In the exemplary implementation, the flow monitor, or QoS monitor, monitors throughput in each of the forward and reverse link directions at the L3CE logical layer. And, estimation of the data flow rate towards the mobile host 14 is used as the value of the throughput in the just-listed equation. The RTT estimate, used above, is calculated according to the following equation: RTT=RTTTCP−(RTTL3CE−RTTOPT) (2) wherein: RTTTCP is an end-to-end round-trip-time calculated utilizing standard TCP mechanisms; RTTL3CE is a round-trip time at the L3CE logical layer. RTTOPT is an optimal round-trip-time over the radio-link, i.e., at the L3CE layer. It should be appreciated from this second equation that RTT provides an estimate of the end-to-end round-trip time minus the time spent in performing retransmission over the radio link. It should also be appreciated that any logical layer which provides acknowledgments for data packets transmitted over a radio link could be used to provide the required estimates of round trip times over the air interface. Following is the manner, in the exemplary implementation, by which the RTTL3CE is measured. When a mobile host is sending an IP packet, the packet is offered to the L3CE layer 128. At such layer, the packet is forwarded to lower layers upon which the L3CE layer resides. At the lower layers, the packet is divided into smaller segments which are transmitted over a radio-link. If corruption occurs, the segments are retransmitted. Once the entire L3CE packet is successfully transmitted, the L3CE layer at the mobile host is informed by an acknowledgment message transmitted from the receiving host, e.g., a network. element of the radio access network. The mobile host is then able to calculate the RTTL3CE by measuring the time interval between the transmission time of L3CE packets and the arrival time of acknowledgments thereto. The mobile host, could, for example, maintain a table pertaining to recently transmitted L3CE packets. When a segment is passed to a lower layer, the flow to which the packet belongs is identified, e.g., either by a flow ID, or, an IP destination and source address. The TCP destination and source ports and the protocol field, a sequence number and transmission timer is marked in the table. When acknowledgment of the packet is passed from the lower layers to the L3CE layer, the arrival time of the acknowledgment is marked in the table. The segment corresponding to the arrived acknowledgment can then be recognized from the flow ID and the sequence number. The time difference between such markings on the table is the RTTL3CE value. In an implementation in which the L3CE layer does not make acknowledgments, the RLC layer effectuates the acknowledgments. In any event RTT over RAN is measurable at least at one of the layers. The RTTL3CE value calculated as such, cannot be used to estimate the optimal window size, OWND, as only the time spent in retransmissions over the radio-link should be subtracted from the overall TCP round-trip-time RTTTCP. As a result, RTTOPT, which describes the L3CE layer round-trip time in optimal circumstances, i.e., exclusive of bit errors and retransmissions, must first be subtracted from the value of RTTL3CE. RTTOPT can be determined by utilizing information that a WCDMA-RLC/MAC layer provides. The RLC/MAC layer, for instance, measures RLC layer round-trip time, which is then used in RLC layer for control. The same information, i.e., RLC layer RTT, can alternately be utilized to calculate the RTTOPT value needed. In another implementation, the value of RTTOPT is determined experimentally at different bandwidths and such experimentally determined values are stored in the mobile host for use in round-trip-time calculations. The optimal transmission window size, OWND, is then calculated utilizing radio-link status data. The new value of the OWND is then added to an offered window field in a subsequent TCP acknowledgment, or data packet sent from the mobile host to the network host. A network host running in a normal standard TCP protocol handles OWND as it handles normal offered window indications. The network host utilizes OWND as the maximum value for its transmission window. Therefore, there is no need to modify the TCP/IP stack at the network host. TCP flow control is further effectuated by controlling the manner, and when, TCP retransmission timers are adjusted. In the TCP specification, retransmission timer management is governed according to the following equations: E=RTTM−RTTA RTTA←RTTA+gE (3) D←D+h(abs(E)−D) RTO=RTTA+4D wherein: RTTM is a most recent RTT measurement; RTTA is a smoothed estimator or RTT average; D is a smoothed mean deviation; RTO is a value of a retransmission timer; and h and g are constants of values of 0.25 and 0.125, respectively. In this embodiment, radio-link status information is utilized to identify significant changes in throughput or link quality, and therefrom to adjust the retransmission timers to avoid spurious time-outs and subsequent retransmissions. As a result, additional time is provided for standard TCP retransmission timer adjustment, allowing the timer management to settle down to a newly adjusted value. According to an embodiment of the present invention, a value of RTTl3CE is measured for each data packet or segment. When such significant increments in the measured values of round-trip-times (i.e. RTTL3CE) are detected, information about the change in the values is passed on to a TCP layer. The RTO, above-defined, of each TCP packet currently on-transmission is prolonged thereby to avoid spurious retransmissions. Spurious TCP retransmissions are decreased in situations in which the mobile host sends data and either the available bandwidth over the radio-link or the radio-link quality deteriorates significantly. Link layer status information is utilized in the timer adjustment. When deterioration is detected, the TCP retransmission timer values are prolonged. Advantageously, this is done both to the TCP packets that have already been transmitted and the timer is currently running as well as to at least subsequent packet to be next transmitted. In this manner, the network has more time to effectuate retransmissions at the lower layers, (e.g., the RLC layers) prior to timing out of the TCP timers, resulting in retransmissions of TCP packets. It should be noted that prolonging an RTO does not affect RTT estimations. The timers may also be extended for one or more packets still remaining to be transmitted. An RTTL3CE estimation table, described above, is also utilized to detect changes in the radio-link. When the quality of the link or radio resource available for the TCP flow decreases, values of the RTTL3CE estimations increase. As the table includes history information of RTTL3CE measurements such changes are detectable. The difference, between, for instance, the two most-recent RTTL3CE measurements is the time interval used in connection with retransmission timer adjustment. When the mobile host is about to send a TCP data packet, the RTTL3CE table is accessed to determine whether there has been a significant change between the latest measurements of the TCP data flow. If there has not been a significant change, the TCP sets the retransmission timer in a conventional manner. If, however, the status of the radio-link has changed, the difference between the latest RTTL3CE measurements of that specific data flow, TD is calculated and added to the TCP retransmission timer for the data flow in question. The significance of changes between successive measurements of TCP data flow can be determined, e.g., by measuring a deviation D in the previously determined RTTTCP values, which may be calculated as shown in the previous equations. If TD is greater than, e.g., 4D, a significant change is defined, and the TCP timers are prolonged. Examination of the effect of different choices on the number of spurious TCP retransmissions under given conditions might result in a selection of another threshold value, defining the significance of changes in TCP data flow. TD is also added to the timers of the TCP packets that have already been transmitted. To do so, the TCP implementation must be such that if the retransmission timer times-out, retransmission of TCP packets is not performed unconditionally. Instead, a check is made to see whether there is a need to prolong the timer. If there is, a new timer with a value TD is started and, if this timer also times-out, a normal standardized retransmission procedure is effectuated. In the event that there is no need to prolong the original timer, a normal retransmission procedure is performed subsequent to expiration of the timer. Advantageously, when a significant change in TD is detected, the timers of the packet to be transmitted subsequently and also N following packets are prolonged. To determine an appropriate value of N the constants h and g in the preceding equations can be used. Conventionally, such constants determine the effect of the most recent measurements of RTT and deviation D on the value of RTO. Consequently, according to an embodiment of the invention, N is chosen so that after N segments, the normal RTO estimation procedure has enough time to settle down to the new value and timers need not be prolonged by TD anymore. A proper value of N can, for instance, be experimentally determined, such as by setting N to 1/h. FIG. 3 illustrates a flow diagram, shown generally at 224, representing the manner by which retransmission timers are adjusted during operation of an embodiment of the present invention. Advantageously, and as previously explained, all operations illustrated in the flow diagram are performed at a mobile host, which is assumed to be taking part in packet data communication over a radio link with e.g. a network host in the fixed line part of a telecommunications network. Furthermore, the steps of the method described by the states of the flow diagram are performed advantageously for each active data flow between the mobile host and the network host. A first block 226 represents the transmission and reception of data at a L3CE layer. Alternatively, if the L3CE layer does not provide a mechanism by which acknowledgments are provided for transmitted data, another layer, for example an RLC layer, that does provide acknowledgments can be used. When a data packet is transmitted from the mobile host to the network host, the packet transmission time is marked in a time table 228. An indication of the data flow to which the packet belongs is also provided in the table. This indication can take the form of a corresponding flow ID, or alternatively IP addresses, TCP port numbers and protocol ID, or any other indication that uniquely identifies the data flow to which the packet belongs. The operation of marking the packet transmission time and corresponding flow ID in the time table is represented by the path taken from the transmission and reception block 226 to time table 228. When a corresponding acknowledgment for the packet is received from the network host, the time of arrival of that acknowledgment is also marked in the time table 228. Paths are also taken from time table 228 to an RTTL3Ce calculation block 232 and to an RTTL3CE change detection block 234. To estimate L3CE round trip time RTTL3CE, the time table is accessed to read transmission and reception times recorded therein. In block 232 the round trip time at the L3CE layer is determined and the result of the calculation is entered into the time table, as indicated by the arrow directed from state 232 to time table 228. In order to detect the change in the RTTL3CE, the time table is accessed and the latest RTTL3CE values are collected. The change in RTTL3CE between, for example, the most recent RTTL3CE values, is determined in block 234. The change TD is passed forward to a delay selection block 236. In addition to the value of TD , delay selection block 236 receives input from a conventional TCP retransmission timer (RTO) estimation block 238. The values of D, g and h, defined according to equation set 3, used in conventional TCP retransmission timer adjustment, are passed to delay selection block 236. Input relating to TCP layer round trip time measurements is also received by block 238 from block 244 (described later) for use in estimation of the standard TCP RTT value. In delay selection block 236 the values of TD and D are used to determine if the change in RTTL3CE is significant, in other words, whether there is a need to prolong the TCP retransmission timers. If it is determined that re-adjustment is necessary, the subsequent number of TCP packets to be affected by the change, i.e., N is determined using g and/or h and TD . The values of N and TD are passed forward to a TCP retransmission timer control block 242. TCP retransmission timer control block 242 also receives input from the standard TCP RTO estimation block 238, indicating the value of the RTOTCP calculated using the conventional TCP retransmission timer calculation logic. TCP retransmission timer control logic in block 242 controls the retransmission timers. If timer re-adjustment is necessary, the timer control logic re-adjusts timers that are currently running by calculating a new prolonged retransmission timer value and passing that forward to TCP/IP data packet transmission and reception and timers block 244. The value of a retransmission timer RTO to be used for subsequent data packets is also determined in block 242 by adding the value of TD received from delay selection block 236 to the value of RTOTCP received from the standard TCP RTO estimation block 238. This new value of RTO is applied to the following N data packets, as indicated by the value of N received from delay selection block 236. If there is no need for retransmission timer re-adjustment, the standard TCP RTO value obtained from block 238 is utilized. In the TCP/IP data packet transmission and reception and timers block 244 data is exchanged with the L3CE data transmission and reception block 226. In the functional state represented by the block 226, retransmission timers whose values are controlled by block 244 are used for currently proceeding and subsequent data packet transmissions. In order to enable the adjustment of currently running retransmission timers in accordance with the method of the invention, the retransmission timer implementation is such that if there is found to be a need to prolong a running timer, a new timer is started immediately after expiration of the running timer. In this way a timer that is already running may be effectively extended in accordance with the RTO value provided by state 244. TCP layer round trip time measurements are also passed from block 244 to block 238 for use in the standard RTO estimation. FIG. 4 illustrates a flow diagram, shown generally at 252, representing the manner by which to estimate an optimal window value OWND for a TCP offered window during operation of an embodiment of the present invention. Advantageously, and as previously explained, all operations illustrated in the flow diagram are performed at a mobile host, which is assumed to be taking part in packet data communication over a radio link with e.g. a network host in the fixed line part of a telecommunications network. Furthermore, the steps of the method described by the flow diagram are performed advantageously for each active data flow between the mobile host and the network host. A first block 254 represents the transmission and reception of data at an L3CE layer. Alternatively, if the L3CE layer does not provide a mechanism by which acknowledgments are provided for transmitted data, another layer, for example an RLC layer, that does provide acknowledgments can be used. When a data packet is transmitted from the mobile host to the network host, the packet transmission time is marked in a time table 256. An indication of the data flow to which the packet belongs is also provided in the table. This indication can take the form of a corresponding flow ID, or alternatively IP addresses, TCP port numbers and protocol ID, or any other indication that uniquely identifies the data flow to which the packet belongs. The operation of marking the packet transmission time and corresponding flow ID in the time table is represented by the path taken from the transmission and reception block 254 to time table 256. When a corresponding acknowledgment for the packet is received from the network host, the time of arrival of that acknowledgment is also marked in the time table 256. Round trip times at the L3CE layer are calculated at RTTL3CE calculation block 258. To estimate RTTL3CE, time table 256 is accessed to read the transmission and reception times.recorded therein. RTTLL3CE is determined at block 258 and the result of the calculation is entered into the time table, as indicated by the arrow directed from block 258 to time table 256. At RTT calculation block 260, an estimate of the round trip time RTT is obtained, preferably according to the expression presented earlier. As explained previously, according to this equation, RTT is defined so as to represent an estimate of the end-to-end round trip time minus the amount of time spent in performing retransmissions over the radio link that forms at least part of the communication path. In order to calculate RTT, RTT calculation block 260 uses values relating to round trip time at the L3CE layer (RTTL3CE) obtained from time table 256 and an estimate of end-to-end round trip time, i.e. RTTTCP, from a standard TCP RTO estimation block 268 (described below). In order to perform calculation of RTT according to the exemplary embodiment of the invention, RTT calculation block 250 further receives an estimate of the optimum round trip time over the radio link RTTOPT provided by a UMTS flow monitor, denoted by block 262 in FIG. 4. The transfer of information concerning RTTOPT from UMTS flow monitor 262 to RTT calculation block 260 is represented by a dotted line in order to indicate that in some implementations UMTS flow monitor 262 may not be able to provide indications of the radio link status and is therefore unable to provide information about RTTOPT. In this case, and as previously described, alternative methods for providing information about RTTOPT can be used. For example, values of RTTOPT at different bandwidths determined experimentally and stored in the mobile host can be used in the calculation of RTT. However, in the remainder of this description, it will be assumed that information relating to RTTOPT is provided by the UMTS flow monitor and is available for use in determination of RTT. An optimal value for the size OWND of a transmission window to be used at least in transmissions from the network host to the mobile host is calculated at OWND calculation block 264 using input regarding L3CE layer throughput obtained from UMTS flow monitor 262 and the value of RTT obtained from RTT calculation block 260. The resulting OWND size is passed to the TCP/IP transmission and reception block 266, which also includes timer and timer control functionality. As shown in FIG. 4, a standard TCP RTO estimation block 268 is also provided to estimate TCP retransmission timer values in a conventional manner, for example according to Equation set 3. The TCP RTO estimation block 268 receives information concerning end-to-end round trip times (i.e., RTTTCP) from TCP/IP transmission and reception block 266 for use in the calculation of retransmission timer value RTO. An RTO value calculated in block 268 is passed forward to TCP/IP transmission and reception block 266 where it is used to control TCP retransmission timers. The TCP/IP transmission and reception block 266 further exchanges data with L3CE data transmission and reception block 254. The optimal transmission window size OWND is passed to L3CE data transmission block 254 where it is added to TCP packets or acknowledgments sent to the network host, for subsequent use by the network host as a maximum data transmission window size. Advantageously, the mobile host also uses the value of OWND as a maximum TCP transmission window size in its own transmissions to the network host. Operation of an embodiment of the present invention permits improvement in packet communications upon a communication path including a radio-link. By taking into account the conditions of the radio-link to control data flow, congestion which might otherwise occur as a result of packet losses on the radio-link is reduced. An embodiment of the present invention is further implementable to effectuate mobile-to-mobile communication by way of a fixed, e.g., UMTS, network. The above-described apparatus and method, in such an implementation, is utilized at both radio-links extending to both of the mobile hosts. The mechanisms described by the state diagrams of FIGS. 3 and 4 are advantageously used together to provide the best possible improvement in packet data communication. Of course, either one could be used separately. But, as they use the same information relating to the status of the radio link (i.e., the values RTTL3CE recorded in the time table, it seems that an embodiment of the present invention advantageously includes the use of both mechanisms in parallel. The previous descriptions are of preferred examples for implementing the invention, and the scope of the invention should not necessarily be limited by this description. The scope of the present invention is defined by the following claims:
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<SOH> BACKGROUND OF THE INVENTION <EOH>Advancements in communication technologies have permitted the introduction of, and popularization of, new types of communication systems. As a result of such advancements, significant increases in the rates of data transmission, have been permitted. And, new types of communication services have also been made possible. A radio communication system is exemplary of a type of communication system which has benefited from advancements in communication technologies. At least a portion of a communication path utilized in a radio communication system includes a radio-link. A radio communication system inherently increases communication mobility as communication channels defined in such a system are formed of radio channels and do not require wireline connections for their formation. Advancements in digital communication techniques are amongst the advancements in communication technologies which have permitted the introduction of the new types of communication systems. Communications effectuated through the use of digital communication techniques are generally of improved bandwidth efficiencies in comparison to communications effectuated utilizing conventional, analog techniques. A packet data communication system is also exemplary of a communication system made possible as a result of advancements in communication technologies. In a packet communication system, groups of digital bits are formatted into packets to form packets of data. The packets of data are communicated, either individually, or in groups, at discrete intervals. Once received, the packets of data are concatenated together to recreate the informational content of the digital bits of which the packets are formed. Because packets of data can be communicated at discrete intervals, the communication channel upon which the packets are transmitted need not be dedicated to a single communication pair. Instead, a shared communication channel can be used by a plurality of communication pairs to communicate packets of data on the shared channel. Standardized protocols by which to format and to communicate packets of data have been developed. A TCP/IP (transmission control protocol/ Internet protocol) is exemplary of a packet formatting scheme. And, an X.25 protocol describes another exemplary protocol scheme. Standards relating to conventional packet communication systems have been promulgated for both conventional wireline, as well as wireless, systems. Packet radio services have been proposed, for instance, for several different cellular communication systems. A cellular communication system is a type of radio communication system, widely implemented and popularly-used. Exemplary of such a packet radio service is the GPRS (General Packet Radio Service) system for GSM (Global System for Mobile Communications). One proposal is for a so-called 3G (third generation) cellular communication system, referred to as a UMTS (universal mobile telecommunications system) network. Packet data communications are provided for therein. In this proposed system, as well as others, packet data is communicated between a mobile host and a network host. A communication path formed between the mobile and network hosts includes at least one radio-link formed between the mobile host and infrastructure of the UMTS network. Proposals related to the UMTS network include the use of TCP/IP protocols for end-to-end communications, viz., for communications over the wireless and also the fixed parts of the UMTS network. Such a service is typically a “best effort” service, i.e., a service without a guaranteed quality of service. The infrastructure of the UMTS network includes both a wireline IP-based UMTS core network and a radio part, i.e., a radio-link, formed between the mobile host and a base station, forming a portion of the UMTS core network. TCP-based protocols have, however, conventionally been designed for conventional, wireline networks. In conventional TCP protocols, measures intended to control the flow of data and possible congestion within the communication network are designed according to the characteristics of wireline networks where packet losses are often the result of congestion. Congestion arises, for instance, because of the aforementioned sharing of communication resources for different communication pairs. When a packet communication system is implemented in wireless form, however, packet losses are often due to bit errors and/or packet losses introduced during transmission on a radio-link. Because a UMTS network includes both a wireline, core network and also a radio part, packet losses occurring at the radio part, such as due to communication handovers or corruption on the radio-link are retransmitted locally. When the UMTS is defined in terms of logical layers, local retransmission means, for example, that data packets are retransmitted over the radio link by a radio-link control (RLC) layer. These local retransmissions decrease end-to-end throughput between the mobile and network hosts due to the time required to effectuate the local retransmissions. If a conventional TCP protocol is used in connection with a data transmission network, such as a UMTS network, implemented at least in part over a radio communication link, a sending station originating TCP data continues sending packet data at a constant rate, irrespective of the local retransmissions at the radio part of the network. Thus, the possibility for congestion of the UMTS core network increases, as new packets are transmitted from the network host in the fixed line part of the network while earlier packets are still undergoing retransmission over the radio link to recover from losses in the radio-link. Deleterious results, such as spurious time-outs of the sending station, can occur, significantly reducing the end-to-end performance of the network. Spurious time-outs occur because of the additional time taken to receive acknowledgments for data packets that are retransmitted over the radio-link under local control of a radio link control layer (RLC). If data packets are retransmitted by the radio link control layer, additional time elapses before the sending TCP protocol in the mobile host receives an acknowledgment that a particular packet has been received by the receiving host e.g. in the fixed line part of the network. By the time an acknowledgment is received, the TCP,retransmission timer in the mobile host may have already expired and conventional congestion control measures may have been initiated by the sending TCP, resulting in decreased data throughput. Furthermore, in this situation, initiation of conventional congestion control mechanisms is erroneous because the delayed acknowledgment was due to the additional time required for retransmission over the radio link, rather than real congestion in the network. According to the invention, this erroneous initiation of TCP congestion control measures is prevented by increasing TCP timer time-out values in conditions where there is an increased likelihood of retransmission over the radio link, for example in situations where there is degradation in the quality of the radio-link or a decrease in the bandwidth available for communication over the radio link. On the other hand, if true congestion of the communication network occurs, the method according to the invention still allows conventional congestion control measures to be initiated. If a manner could be provided by which better to effectuate packet data transmission by a sending station to take into account the performance of the radio part of the system, improved system operation would result. QoS (Quality of Service) levels are also proposed to be defined in the UMTS network. The QoS levels define, in general, performance parameters pursuant to which a particular communication service is to be effectuated. Several communication services are non-real-time services, such as communications with the WWW (World Wide Web), TELNET™, e-mail services, etc. Applications to effectuate such services, logically, run on top of a TCP logical layer. And, such communication services typically are implemented at QoS levels referred to as“best-effort” traffic classes. Such traffic classes do not give guarantees of available bandwidth and, hence, delivery times. Conversely, communication services which are of a real-time nature typically are implemented at higher QoS levels and such communication services are effectuated with a higher priority than non-real-time TCP-related services. Because of the lower priority levels of the TCP-related, non-real-time services, the bandwidth available to effectuate such services is susceptible to rapid change. Conventional manners by which to effectuate TCP flow control do not include a manner by which to set transmission rates according to such rapid changes. In conventional TCP implementations, a standard mechanism, referred to as self-clocking behavior is used to limit the transmission rate of a sending station. Self-clocking behavior refers to a manner by which the sending station is able to send a new packet, responsive to reception of an acknowledgment of an earlier-transmitted packet, if the size of the transmission window remains constant. In conventional TCP operation, however, the transmission window is not constant. Instead, the transmission window is of a size which is adjusted regularly, according to the arrival of acknowledgments and occurrence of retransmission time-outs. In practice, then, in standard operation, a sending station increases a transmission window size until some point in a communication path, such as the radio access node (RAN). Thereafter, congestion control mechanisms are implemented, but such implementations abruptly slow down transmission rates of communications. This behavior also results in reduced end-to-end throughput rates. If a manner could be provided by which better to effectuate communication of packet data by taking into better account changes of bandwidth availabilities for the communication of the packet data, improved system operation would further result. It is in light of this background information related to packet data communications that the significant improvements of the present invention have evolved.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention, accordingly, advantageously provides apparatus and an associated method, by which more optimally to communicate data packets in a packet communication system, such as a UMTS (Universal Mobile Telecommunications System) wireless data network. Operation of an embodiment of the present invention better optimizes the size of a transmission window within which a sending station sends a packet of data. By better selecting the size of the transmission window, the throughput rates of data communication of the packet data is improved. Operation of a further, or alternate, embodiment of the present invention provides a manner by which to adjust a retransmission timer responsive to changes in the characteristics of a radio-link upon which data packets are communicated. The timer is adjusted in a manner to reduce the occurrence of spurious retransmissions as a result of changing radio-link conditions. In one aspect of the present invention, apparatus is provided for a mobile station, herein referred to as a mobile host, by which to select an optimal transmission window within which a data packet is to be transmitted thereto by a network host. Determination is made at the mobile host of the optimal size of the transmission window responsive to determination of throughput rates, or other link status indication related to the radio-link. Responsive to the measured, or otherwise determined, indication, selection is made of the optimal transmission window size. A value respective of the optimal transmission window size is then sent to the network host. The optimal transmission window size is used by the network host as a maximum size of the transmission window within which the network host thereafter transmits a data packet. In another aspect of the present invention, apparatus is provided for a mobile host to select a time-out value for a retransmission timer of the mobile host. Measurement, or other determination, of a radio-link quality indication is made. Responsive to a value of the radio-link quality being beyond a threshold value, the timer's time out value is adjusted. In one implementation, the radio link quality indication is representative of changes in communication quality levels. For example, if a significant deterioration in the quality of the radio link is indicated, the time-out of the retransmission timer is increased. In a packet data communications network implemented at least in part over a radio link, time-out values which are too low can cause spurious time-outs. This happens because of the additional time taken to perform retransmission over the radio link, under the control of a radio link control layer, for example. As previously explained, this results in decreased throughput as congestion control procedures are started, but performance of such procedures is in vain. In a situation in which real congestion of the core network exists, the mobile host does not use an excessively large window. In one implementation, improved TCP flow control is provided for a mobile host operable in an IP network. Improved throughput rates are made possible by determinations made at the mobile host of indications related to the TCP communications upon a radio link forming a portion of the communication path between the mobile host and a network host (or any sending TCP station). Link layer status information at a radio link control layer which specifically provides information about the radio-link is used to optimize communications. Throughput and link status data is used to set an optimal TCP offered window size. And, such data is also used to improve the ability of the retransmission timers of the mobile host to react to changes in the link status or in available bandwidth. In one embodiment, all necessary determinations and selections required for operation of the embodiment of the present invention are effectuated at the mobile host. In a further implementation, apparatus is provided for a UMTS mobile terminal to optimize better TCP protocols to account for flow and congestion characteristics of wireless communication links. In contrast to conventional TCP flow and congestion control measures, which are specifically designed for fixed networks, operation of an embodiment of the present invention takes into account radio-link characteristics to optimize TCP transmission parameters. Data throughput and radio-link status indications, e.g., from a UMTS protocol stack, are used to set an optimal TCP window size. And, the data throughput and radio-link status indications are also used to improve the ability of TCP retransmission timers of the mobile terminal to react to changes in the link status or in available bandwidth. Implementation of the various embodiments of the present invention can be effectuated entirely at the mobile terminal, thus requiring no changes to fixed network elements, such as IP routers or network terminals. In these and other aspects, therefore, apparatus, and an associated method, is provided for a first host operable in a communication system in which packet data is communicated between the first host and a second host upon a communication path in which the communication path includes a radio-link. The apparatus, and associated method, selects an optimal window size within which to transmit a data packet. A radio-link status determiner is coupled to receive indications of the radio-link forming a portion of the communication path between the first host and the second host. The radio-link status determiner determines an indication of a characteristic of the radio-link. The radio-link status determiner also generates a radio-link status indication indicative of the indication of the characteristic determined thereat. An optimal window size selector is coupled to receive the radio-link status indication generated by the radio-link status determiner. The optimal window size selector selects an optimal window size within which to transmit the data packet. In these and other aspects, apparatus, and an associated method, are also provided for a communication system in which packet data is communicated between a first host and a second host upon a communication path. The communication path includes a radio-link, and the first host has a retransmission timer at least for selecting when to retransmit the data packet. Selection is made of a time-out value of a retransmission timer. A radio-link status determiner is coupled to receive indications of the radio-link forming a portion of the communication path between the first host and the second host. The radio-link status determiner determines an indication of radio-link quality of the radio-link. The radio-link status determiner also generates a radio-link quality indication indicative of the indication of the radio-link quality determined thereat. A retransmission timer time-out value selector is coupled to receive a value representative of the radio-link quality indication generated by the radio-link status determiner. The retransmission timer time-out value selector selects a time-out value of the retransmission timer. Selection is made responsive to the value representative of the radio-link quality indication. A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings, which are briefly summarized below, the following description of the presently-preferred embodiments of the invention, and the appended claims:
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20040628
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20150414
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20050224
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78485.0
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SWEET, LONNIE V
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APPARATUS, AND ASSOCIATED METHOD, FOR COMMUNICATING PACKET DATA IN A NETWORK INCLUDING A RADIO-LINK
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UNDISCOUNTED
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CONT-ACCEPTED
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10,880,035
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ACCEPTED
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Method for manufacturing semiconductor device
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The present invention discloses a method for manufacturing a semiconductor device, comprising the steps of: providing a semiconductor substrate on which cell strings are formed and in which a plurality of conductive regions are formed; sequentially forming a first interlayer insulation film and a first etch barrier film on the semiconductor substrate; forming a plurality of contact holes by exposing the plurality of conductive regions formed in the semiconductor substrate, wherein an impurity concentration of the conductive regions is reduced due to the process for forming the contact holes; filling a metal material in the contact holes and forming a plurality of contact plugs; sequentially forming a second interlayer insulation film, a second etch barrier film and a third interlayer insulation film over a resulting structure including the contact plugs; forming a plurality of metal line patterns, wherein the metal line patterns pass through the third interlayer insulation film, the second etch barrier film and the second interlayer insulation film and contact to the contact plugs; forming a fourth interlayer insulation film over a resulting structure including the plurality of metal line patterns; forming a plurality of metal line contact holes by patterning the fourth interlayer insulation film; and forming a plurality of metal line contact plugs in the plurality of metal line contact holes by filling a metal material in the metal line contact holes.
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1. A method for manufacturing a semiconductor device, comprising the steps of: providing a semiconductor substrate on which cell strings are formed and in which a plurality of conductive regions are formed; sequentially forming a first interlayer insulation film and a first etch barrier film on the semiconductor substrate; forming a plurality of contact holes by exposing the plurality of conductive regions formed in the semiconductor substrate, wherein an impurity concentration of the conductive regions is reduced due to the process for forming the contact holes; filling a metal material in the contact holes and forming a plurality of contact plugs; sequentially forming a second interlayer insulation film, a second etch barrier film and a third interlayer insulation film over a resulting structure including the contact plugs; forming a plurality of metal line patterns, wherein the metal line patterns pass through the third interlayer insulation film, the second etch barrier film and the second interlayer insulation film and contact to the contact plugs; forming a fourth interlayer insulation film over a resulting structure including the plurality of metal line patterns; forming a plurality of metal line contact holes by patterning the fourth interlayer insulation film; and forming a plurality of metal line contact plugs in the plurality of metal line contact holes by filling a metal material in the metal line contact holes. 2. The method of claim 1, further comprising the step of increasing the impurity concentration of the conductive regions, after forming the contact holes. 3. The method of claim 1, wherein the metal line patterns are formed by a dual damascene process. 4. The method of claim 3, wherein the dual damascene process includes steps of: forming via holes by patterning the third interlayer insulation film and the second interlayer insulation film; and forming trench patterns by patterning the third interlayer. 5. The method of claim 1, wherein the metal material filled in the contact holes is one of W, Al, Cu, CVD and TiN. 6. The method of claim 1, wherein the metal material filled in the metal line patterns is one of W, Al, Cu, CVD and TiN. 7. The method of claim 1, wherein the metal material filled in the metal line contact holes is one of W, Al, Cu, CVD and TiN. 8. The method of claim 1, wherein any one of the plurality of contact plugs and any one of the plurality of metal line contact plugs are coupled through any one of the plurality of metal lines.
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BACKGROUND 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to, a method for forming metal lines in a NAND flash memory device. 2. Discussion of Related Art FIG. 1 is a cross-sectional diagram illustrating a conventional metal line structure of a NAND flash memory device. A conventional method for forming metal lines will now be explained with reference to FIG. 1. Referring to FIG. 1, a first contact plug 14 exposing a conductive region in a predetermined region of a semiconductor substrate 10b including cell strings 10a is formed by patterning a first interlayer insulation film 12 on the whole surface of the semiconductor substrate 10b. A second contact plug 18 exposing a conductive region except the conductive region in which the first contact plug 14 has been formed is formed by patterning a first interlayer insulation film 12 and a second interlayer insulation film 16 over the resulting structure. First metal lines 28a, 28b and 28c exposing a conductive region except the conductive region in which the first contact plug 14 and the second contact plug 18 have been formed are formed by forming an etch barrier film 20 and a third interlayer insulation film 22 over the resulting structure, and patterning the first, second and third interlayer insulation films 12, 16 and 22. Second metal lines 24 and 26 stacked on the first contact plug 14 and the second contact plug 18 are formed by patterning the second and first interlayer insulation films 16 and 12. Third contact plugs 32a, 32b and 32c exposing the first metal lines 28a, 28b and 28c and the second metal lines 24 and 26 are formed by forming a fourth interlayer insulation film 30 over the resulting structure, and patterning the fourth interlayer insulation film 30. However, the conventional method for forming the multi-layer line structure in the NAND flash memory device has the following disadvantages. First, a contact hole is formed through the first, second and third interlayer insulation films during the process for forming the first metal lines. Therefore, an aspect ratio of the contact hole increases, and thus the contact hole is not efficiently filled. Second, an ion implant process for increasing an impurity concentration which may be reduced in an impurity region after the process for forming the contact hole is performed three times, namely, after forming the contact hole for forming the first contact plug, after forming the second contact hole for forming the second contact plug, and after forming patterns for forming the first metal lines. In order to perform the ion implant process three times, a plurality of processes such as a masking operation are required to prevent ions from being implanted into other films. Accordingly, steps of the whole process are complicated. Third, the first and second contact plugs and the first metal lines use different metal materials, to complicate the steps of the process. SUMMARY OF THE INVENTION The present invention is achieved to solve the above problems. One object of the present invention is to efficiently fill a contact hole by decreasing an aspect ratio of the contact hole. Another object of the present invention is to prevent process failures from occurring in a process for forming metal lines due to a plurality of ion implant processes for increasing an impurity concentration which may be reduced in an impurity region after the process for forming the contact hole, by decreasing a number of the ion implant processes. Yet another object of the present invention is to reduce steps of a process for forming multi-layer metal lines. The present invention is directed to a method for manufacturing a semiconductor device which can achieve the above objects. One aspect of the present invention is to provide a method for manufacturing a semiconductor device, comprising the steps of: providing a semiconductor substrate on which cell strings are formed and in which a plurality of conductive regions are formed; sequentially forming a first interlayer insulation film and a first etch barrier film on the semiconductor substrate; forming a plurality of contact holes by exposing the plurality of conductive regions formed in the semiconductor substrate, wherein an impurity concentration of the conductive regions is reduced due to the process for forming the contact holes; filling a metal material in the contact holes and forming a plurality of contact plugs; sequentially forming a second interlayer insulation film, a second etch barrier film and a third interlayer insulation film over a resulting structure including the contact plugs; forming a plurality of metal line patterns, wherein the metal line patterns pass through the third interlayer insulation film, the second etch barrier film and the second interlayer insulation film and contact to the contact plugs; forming a fourth interlayer insulation film over a resulting structure including the plurality of metal line patterns; forming a plurality of metal line contact holes by patterning the fourth interlayer insulation film; and forming a plurality of metal line contact plugs in the plurality of metal line contact holes by filling a metal material in the metal line contact holes. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional diagram illustrating a conventional metal line structure of a semiconductor device; and FIGS. 2 to 4 are cross-sectional diagrams illustrating sequential steps of a method for manufacturing a semiconductor device in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A method for manufacturing a semiconductor device in accordance with a preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, a thickness of a film is exaggerated to emphasize clear and accurate explanations. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. In addition, in the case that it is described that one film is disposed on or contacts another film or a semiconductor substrate, one film can directly contact another film or the semiconductor substrate, or the third film can be positioned between them. FIGS. 2 to 4 are cross-sectional diagrams illustrating sequential steps of a method for forming metal lines in a semiconductor device in accordance with a preferred embodiment of the present invention. As illustrated in FIG. 2, an HDP oxide film 32 which is a first interlayer insulation film and a first silicon nitride film 34 which is an etch barrier film are sequentially formed on the whole surface of a semiconductor substrate 30b including cell strings 30a. The HDP oxide film 32 is formed at a thickness of 6500Å, and the first silicon nitride film 34 is formed at a thickness of 300Å. A source contact hole (not shown), a drain contact hole (not shown), a gate electrode contact hole (not shown) and an active region contact hole (not shown) are formed, respectively, by forming photoresist patterns (not shown) for defining each region in predetermined regions of the first silicon nitride film 34, namely, a source region-exposed region in a cell region, a drain region-exposed region in the cell region, a gate electrode region-exposed region in a peripheral region, and an active region-exposed region in the peripheral region, and performing an etching process using the photoresist patterns as an etch mask thereon. On the other hand, in this embodiment, the contact hole formation regions are restricted to the conductive regions, such as the source region, the drain region, the gate electrode region and the active region. However, it should be recognized that the contact holes can be formed in any kind of conductive regions. An impurity concentration of the exposed bottom surfaces of the contact holes, namely, the exposed semiconductor substrate 30b is increased by performing an ion implant process on the resulting structure, thereby forming conductive regions. A source contact plug 36a, a drain contact plug 36b, a gate electrode contact plug 36c and an active region contact plug 36d are formed at the same time, by forming a tungsten film over the resulting structure on which the ion implant process has been performed, and performing a planarization process such as a CMP process to expose the first silicon nitride film 34. As shown in FIG. 3, a TEOS oxide film 38 which is a second interlayer insulation film, a second silicon nitride film 40 which is a second etch barrier film, and a silicon oxide film 42 which is a third interlayer insulation film are sequentially formed on the whole surface of the resulting structure on which the contact plugs have been formed. The TEOS oxide film 38 is formed at a thickness of 3000 Å, the second silicon nitride film 40 is formed at a thickness of 300 Å, and the silicon oxide film 42 is formed at a thickness of 3000 Å. Thereafter, first, second, third and fourth metal lines 44a, 44b, 44c and 44d are stacked on the source contact plug 36a, the drain contact plug 36b, the gate electrode contact plug 36c and the active region contact plug 36d, respectively. The first, second, third and fourth metal lines 44a, 44b, 44c and 44d are formed according to a dual damascene process. In more detail, predetermined regions of the silicon oxide film 42, namely, a photoresist pattern (not shown) for defining a via stacked on the source contact plug 36a, a photoresist pattern (not shown) for defining a via stacked on the drain contact plug 36b, a photoresist pattern (not shown) for defining a via stacked on the gate electrode contact plug 36c, and a photoresist pattern (not shown) for defining a via stacked on the active region contact plug 36d are formed, respectively. A via hole (not shown) exposing the source contact plug 36a, a via hole (not shown) exposing the drain contact plug 36b, a via hole (not shown) exposing the gate electrode contact plug 3c, and a via hole (not shown) exposing the active region contact plug 36d are formed by etching the silicon oxide film 42, the silicon nitride film 40 and the TEOS oxide film 38 by using the photoresist patterns (not shown) as an etch mask, respectively. After removing the photoresist patterns (not shown), predetermined regions of the silicon oxide film 42, namely, a photoresist pattern (not shown) for defining a trench pattern in the via hole exposing the source contact plug 36a, a photoresist pattern (not shown) for defining a trench pattern in the via hole exposing the drain contact plug 36b, a photoresist pattern (not shown) for defining a trench pattern in the via hole exposing the gate electrode contact plug 3c, and a photoresist pattern (not shown) for defining a trench pattern in the via hole exposing the active region contact plug 36d are formed, respectively. The trench pattern (not shown) of the source contact plug 36a, the trench pattern (not shown) of the drain contact plug 36b, the trench pattern (not shown) of the gate electrode contact plug 3c, and the trench pattern (not shown) of the active region contact plug 36d are formed by etching the silicon oxide film 42 and the silicon nitride film 40 by using the photoresist patterns (not shown) as an etch mask, respectively. Accordingly, the via hole exposing the source contact plug 36a and the trench pattern, the via hole exposing the drain contact plug 36b and the trench pattern, the via hole exposing the gate electrode contact plug 36c and the trench pattern, and the via hole exposing the active region contact plug 36d and the trench pattern are defined, respectively. A first metal line 44a stacked on the source contact plug 36a, a second metal line 44b stacked on the drain contact plug 36b, a third metal line 44c stacked on the gate electrode contact plug 3c, and a fourth metal line 44d stacked on the active region contact plug 36d are formed by filling tungsten on the whole surface of the resulting structure, and performing a planarization process such as a CMP process to expose the silicon oxide film 42. In the preferred embodiment of the present invention, a via-first method is employed for the method for forming the metal lines by using the dual damascene process. However, all kinds of dual damascene processes can be used. As shown in FIG. 4, a first metal line contact hole (not shown), a second metal line contact hole (not shown) and a third metal line contact hole (not shown) are stacked respectively on the first metal line 44a, the second metal line 44b and the third or fourth metal line 44d, 44c and 44e, by forming a second TEOS oxide film 46 which is a fourth interlayer insulation film over the resulting structure, and patterning the second TEOS oxide film 46. A first metal line contact plug 48a stacked on the first metal line 44a, a second metal line contact plug 48b stacked on the second metal line 44b, and a third metal line contact plug 48c stacked on the third or fourth metal line 44d, 44c and 44e are formed by filling tungsten in the metal line contact holes (not shown), and performing a planarization process such as a CMP process to expose the second TEOS oxide film 46. On the other hand, in this embodiment, tungsten is used as the metal material filled in the contact holes and the metal lines. However, aluminum, copper, CVD and TiN can also be used. In accordance with the present invention, the method for manufacturing the semiconductor device has the following advantages. First, only one metal material, namely, tungsten is used as the filling material of the contact holes, to reduce a number of processes. Second, at least two-layer stack type contact plugs are formed by performing the process for forming the contact plugs on each layer, to improve contact filling conditions. Third, the ion implant process is performed merely in the contact plug process exposing the conductive regions, and not performed on the succeeding stacked metal lines and metal line contact plugs, thereby reducing the number of the processes. Fourth, the ion implant process is not performed on the succeeding stacked metal lines and metal line contact plugs. Therefore, a width of the interlayer insulation films is not reduced due to the ion implant process, thereby restricting crosstalk between the metal lines or the metal line contact plugs. Fifth, when the lower contact plugs are damaged during the process for forming the metal lines which will be stacked thereon, the damaged contact plugs are filled in the process for filling the metal lines. Accordingly, the damaged contact plugs are reduced. As discussed earlier, in accordance with the present invention, the method for manufacturing the semiconductor device has the following advantages. First, only one metal material, namely, tungsten is used as the filling material of the contact holes, to reduce a number of processes. Second, at least two-layer stack type contact plugs are formed by performing the process for forming the contact plugs on each layer, to improve contact filling conditions. Third, the ion implant process is performed merely in the contact plug process exposing the conductive regions, and not performed on the succeeding stacked metal lines and metal line contact plugs, thereby reducing the number of the processes. Fourth, the ion implant process is not performed on the succeeding stacked metal lines and metal line contact plugs. Therefore, a width of the interlayer insulation films is not reduced due to the ion implant process, thereby restricting crosstalk between the metal lines or the metal line contact plugs. Fifth, when the lower contact plugs are damaged during the process for forming the metal lines which will be stacked thereon, the damaged contact plugs are filled in the process for filling the metal lines. Accordingly, the damaged contact plugs are reduced. Although the present invention has been described in connection with the embodiment of the present invention illustrated in the accompanying drawings, it is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and changes may be made thereto without departing from the scope and spirit of the invention.
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<SOH> BACKGROUND <EOH>1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to, a method for forming metal lines in a NAND flash memory device. 2. Discussion of Related Art FIG. 1 is a cross-sectional diagram illustrating a conventional metal line structure of a NAND flash memory device. A conventional method for forming metal lines will now be explained with reference to FIG. 1 . Referring to FIG. 1 , a first contact plug 14 exposing a conductive region in a predetermined region of a semiconductor substrate 10 b including cell strings 10 a is formed by patterning a first interlayer insulation film 12 on the whole surface of the semiconductor substrate 10 b. A second contact plug 18 exposing a conductive region except the conductive region in which the first contact plug 14 has been formed is formed by patterning a first interlayer insulation film 12 and a second interlayer insulation film 16 over the resulting structure. First metal lines 28 a , 28 b and 28 c exposing a conductive region except the conductive region in which the first contact plug 14 and the second contact plug 18 have been formed are formed by forming an etch barrier film 20 and a third interlayer insulation film 22 over the resulting structure, and patterning the first, second and third interlayer insulation films 12 , 16 and 22 . Second metal lines 24 and 26 stacked on the first contact plug 14 and the second contact plug 18 are formed by patterning the second and first interlayer insulation films 16 and 12 . Third contact plugs 32 a , 32 b and 32 c exposing the first metal lines 28 a , 28 b and 28 c and the second metal lines 24 and 26 are formed by forming a fourth interlayer insulation film 30 over the resulting structure, and patterning the fourth interlayer insulation film 30 . However, the conventional method for forming the multi-layer line structure in the NAND flash memory device has the following disadvantages. First, a contact hole is formed through the first, second and third interlayer insulation films during the process for forming the first metal lines. Therefore, an aspect ratio of the contact hole increases, and thus the contact hole is not efficiently filled. Second, an ion implant process for increasing an impurity concentration which may be reduced in an impurity region after the process for forming the contact hole is performed three times, namely, after forming the contact hole for forming the first contact plug, after forming the second contact hole for forming the second contact plug, and after forming patterns for forming the first metal lines. In order to perform the ion implant process three times, a plurality of processes such as a masking operation are required to prevent ions from being implanted into other films. Accordingly, steps of the whole process are complicated. Third, the first and second contact plugs and the first metal lines use different metal materials, to complicate the steps of the process.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is achieved to solve the above problems. One object of the present invention is to efficiently fill a contact hole by decreasing an aspect ratio of the contact hole. Another object of the present invention is to prevent process failures from occurring in a process for forming metal lines due to a plurality of ion implant processes for increasing an impurity concentration which may be reduced in an impurity region after the process for forming the contact hole, by decreasing a number of the ion implant processes. Yet another object of the present invention is to reduce steps of a process for forming multi-layer metal lines. The present invention is directed to a method for manufacturing a semiconductor device which can achieve the above objects. One aspect of the present invention is to provide a method for manufacturing a semiconductor device, comprising the steps of: providing a semiconductor substrate on which cell strings are formed and in which a plurality of conductive regions are formed; sequentially forming a first interlayer insulation film and a first etch barrier film on the semiconductor substrate; forming a plurality of contact holes by exposing the plurality of conductive regions formed in the semiconductor substrate, wherein an impurity concentration of the conductive regions is reduced due to the process for forming the contact holes; filling a metal material in the contact holes and forming a plurality of contact plugs; sequentially forming a second interlayer insulation film, a second etch barrier film and a third interlayer insulation film over a resulting structure including the contact plugs; forming a plurality of metal line patterns, wherein the metal line patterns pass through the third interlayer insulation film, the second etch barrier film and the second interlayer insulation film and contact to the contact plugs; forming a fourth interlayer insulation film over a resulting structure including the plurality of metal line patterns; forming a plurality of metal line contact holes by patterning the fourth interlayer insulation film; and forming a plurality of metal line contact plugs in the plurality of metal line contact holes by filling a metal material in the metal line contact holes.
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20040629
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20060718
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20050505
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69352.0
| 0
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SNOW, COLLEEN ERIN
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METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,880,059
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ACCEPTED
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System and method for turbine engine anomaly detection
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A system and method is provided for detecting anomalies in turbine engines emanating from the main shaft and/or main shaft bearings. The anomaly detection system includes a sensor data processor and a matrix analysis mechanism. The sensor data processor receives engine sensor data, including main engine speed data during spin down, and formats the engine sensor data into an appropriate matrix. The matrix analysis mechanism receives the sensor data matrix and performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine main shaft and/or bearings. The output of the matrix analysis mechanism is passed to a diagnostic system where further evaluation of the anomaly detection determination can occur.
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1. An anomaly detection system for detecting anomalies in turbine engines, the anomaly detection system comprising: a sensor data processor, the sensor data processor receiving engine sensor data from the turbine engine and formatting the engine sensor data into a sensor data matrix; and a matrix analysis mechanism, the matrix analysis mechanism performing a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine. 2. The system of claim 1 wherein the sensor data includes data from multiple turbine engines on an aircraft, and wherein the sensor data processor formats the sensor data into the sensor data matrix by placing sensor data from each of the multiple turbine engines into a corresponding row in the sensor data matrix. 3. The system of claim 1 wherein the sensor data includes data from multiple spin down occurrences, and wherein the sensor data processor formats the sensor data into the sensor data matrix by placing sensor data from each of the multiple spin down occurrences into a corresponding row in the sensor data matrix. 4. The system of claim 1 wherein the sensor data comprises main shaft speed data. 5. The system of claim 1 wherein the sensor data comprises main shaft speed data taken during turbine engine spin-down. 6. The system of claim 5 wherein the turbine engine spin-down comprises data collected from the turbine engine after fuel flow has been shut off to the turbine engine and between two defined main shaft speeds. 7. The system of claim 1 wherein the matrix analysis mechanism performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine by calculating a singular value from the sensor data and comparing the singular value to a threshold value. 8. The system of claim 7 wherein the matrix analysis mechanism calculates the singular value using a QR decomposition for symmetric matrices. 9. The system of claim 1 wherein the matrix analysis mechanism performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine by calculating a covariance matrix from the sensor data matrix and by calculating at least a second singular value from the covariance matrix and comparing the second singular value to a threshold value. 10. The system of claim 9 wherein a diagnostic conclusion is made after a predetermined number of successive second singular values exceed the threshold value. 11. A method of detecting anomalies in a turbine engine, the method comprising the steps of: a) receiving sensor data from the turbine engine; b) formatting the sensor data into a sensor data matrix; and c) performing a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine. 12. The method of claim 11 wherein the sensor data includes sensor data from multiple turbine engines on an aircraft, and wherein the step of formatting the sensor data into the sensor data matrix comprises placing the sensor data from each of the multiple turbine engines into a corresponding row in the sensor data matrix. 13. The method of claim 11 wherein the sensor data includes sensor data from multiple spin down occurrences, and wherein the step of formatting the sensor data into the sensor data matrix comprises placing sensor data from each of the multiple spin down occurrences into a corresponding row in the sensor data matrix. 14. The method of claim 11 wherein the sensor data comprises main shaft speed data. 15. The method of claim 11 wherein the sensor data comprises main shaft speed data taken during turbine engine spin-down. 16. The method of claim 15 wherein the turbine engine spin-down comprises data collected from the turbine engine after fuel flow has been shut off to the turbine engine and between two defined main shaft speeds. 17. The method of claim 11 wherein the step of performing a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine comprises calculating a singular value from the sensor data and comparing the singular value to a threshold value. 18. The method of claim 17 wherein the step of calculating a singular value from the sensor data comprises using a QR decomposition for symmetric matrices. 19. The method of claim 11 wherein the step of performing a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine comprises calculating a covariance matrix from the sensor data matrix and calculating at least a second singular value from the covariance matrix and comparing the second row singular value to a threshold value. 20. The method of claim 19 further comprising the step of making diagnostic conclusion after a predetermined number of successive second singular values exceed the threshold value. 21. A program product comprising: a) an anomaly detection program, the anomaly detection program including: a sensor data processor, the sensor data processor receiving engine sensor data from the turbine engine and formatting the engine sensor data into a sensor data matrix; and a matrix analysis mechanism, the matrix analysis mechanism performing a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine; and b) signal bearing media bearing said anomaly detection program. 22. The program product of claim 21 wherein the signal bearing media comprises recordable media. 23. The program product of claim 21 wherein the signal bearing media comprises transmission media. 24. The program product of claim 21 wherein the sensor data includes data from multiple turbine engines on an aircraft, and wherein the sensor data processor formats the sensor data into the sensor data matrix by placing sensor data from each of the multiple turbine engines into a corresponding row in the sensor data matrix. 25. The program product of claim 21 wherein the sensor data includes data from multiple spin down occurrences, and wherein the sensor data processor formats the sensor data into the sensor data matrix by placing sensor data from each of the multiple spin down occurrences into a corresponding row in the sensor data matrix. 26. The program product of claim 21 wherein the sensor data comprises main shaft speed data. 27. The program product of claim 21 wherein the sensor data comprises main shaft speed data taken during turbine engine spin-down. 28. The program product of claim 27 wherein the turbine engine spin-down comprises data collected from the turbine engine after fuel flow has been shut off to the turbine engine and between two defined main shaft speeds. 29. The program product of claim 21 wherein the matrix analysis mechanism performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine by calculating a singular value from the sensor data and comparing the singular value to a threshold value. 30. The program product of claim 29 wherein the matrix analysis mechanism calculates the singular value using a QR decomposition for symmetric matrices. 31. The program product of claim 21 wherein the matrix analysis mechanism performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine by calculating a covariance matrix from the sensor data matrix and by calculating at least a second singular value from the covariance matrix and comparing the second singular value to a threshold value. 32. The program product of claim 31 wherein a diagnostic conclusion is made after a predetermined number of successive second singular values exceed the threshold value.
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FIELD OF THE INVENTION This invention generally relates to diagnostic systems, and more specifically relates to diagnostic systems for turbine engines. BACKGROUND OF THE INVENTION Modern mechanical systems can be exceedingly complex. The complexities of modern mechanical systems have led to increasing needs for automated prognosis and fault detection systems. These prognosis and fault detection systems are designed to monitor the mechanical system in an effort to predict the future performance of the system and detect potential faults. These systems are designed to detect these potential faults such that the potential faults can be addressed before the potential faults lead to failure in the mechanical system. One type of mechanical system where prognosis and fault detection is of particular importance is aircraft systems. In aircraft systems, prognosis and fault detection can detect potential faults such that they can be addressed before they result in serious system failure and possible in-flight shutdowns, take-off aborts, delays or cancellations. Modern aircraft are increasingly complex. The complexities of these aircraft have led to an increasing need for automated fault detection systems. These fault detection systems are designed to monitor the various systems of the aircraft in an effort to detect potential faults. These systems are designed to detect these potential faults such that the potential faults can be addressed before the potential faults lead to serious system failure and possible in-flight shutdowns, take-off aborts, delays or cancellations. Turbine engines are a particularly critical part of many aircraft. Turbine engines are commonly used for main propulsion aircraft. Furthermore, turbine engines are commonly used in auxiliary power units (APUs) that are used to generate auxiliary power and compressed air for use in the aircraft. Given the critical nature of turbine engines in aircraft, the need for fault detection in turbine engines is of extreme importance. Traditional fault detection systems for turbine engines have been limited in their ability to detect the occurrence of anomalies in the bearings and main shaft of the turbine engine. Deformations in the shaft can lead to problems in the bearings, and likewise, problems in the bearings can lead to failures in the shaft. In all cases, defects in the shaft and/or bearings can cause severe performance problems in the turbine engines. Unfortunately, detection methods have been unable to suitably detected anomalies in the main shaft and bearings with sufficient accuracy based on the limited data sets available for fault detection. Thus, what is needed is an improved system and method for detecting anomalies in turbine engine main shafts and bearings that can consistently detect anomalies and the problems that result from limited data sets. BRIEF SUMMARY OF THE INVENTION The present invention provides a system and method for detecting anomalies in turbine engines emanating from the main shaft and/or main shaft bearings. The anomaly detection system includes a sensor data processor and a matrix analysis mechanism. The sensor data processor receives engine sensor data, including main engine speed data during spin down, and formats the engine sensor data into an appropriate matrix. The matrix analysis mechanism receives the sensor data matrix and performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine main shaft and/or bearings. The output of the matrix analysis mechanism is passed to a diagnostic system where further evaluation of the anomaly detection determination can occur. BRIEF DESCRIPTION OF DRAWINGS The preferred exemplary embodiment of the present invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and: FIG. 1 is a schematic view of an anomaly detection system; FIG. 2 is a flow diagram illustrating a turbine engine anomaly detection method; FIG. 3 is a graph illustrating exemplary main shaft speed sensor data taken from four engines during spin down; FIG. 4 is a graph illustrating a histogram of the logarithm of the second singular value calculated from a set of flights; and FIG. 5 is a schematic view of an exemplary computer system implementing an anomaly detection system. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a system and method for detecting anomalies in turbine engines emanating from the main shaft and/or main shaft bearings. Specifically, the system and method receives sensor data and uses matrix analysis on the sensor data to detect anomalies in the turbine engine(s). Turning now to FIG. 1, an exemplary anomaly detection system 100 is illustrated schematically. The anomaly detection system 100 includes a sensor data processor 102 and a matrix analysis mechanism 104. The sensor data processor 102 receives engine sensor data, including main engine speed data during spin down, and formats the engine sensor data into an appropriate matrix. The matrix analysis mechanism 104 receives the sensor data matrix and performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine main shaft and/or bearings. The output of the matrix analysis mechanism 104 is passed to a diagnostic system 106 where further evaluation of the anomaly detection determination can occur. Turning now to FIG. 2, a method 200 for turbine engine anomaly detection is illustrated. Method 200 lists the general steps that can be performed in an anomaly detection method using the embodiments of the present invention. The first step 202 is to receive sensor data from the turbine engine, with the sensor data providing the basis for the analysis and anomaly detection. In one embodiment, the sensor data comprises turbine engine speed data. Of course, the sensor data could also include other types of turbine engine data. Other types of data that could be used include exhaust gas temperature data, oil inlet pressure data, fan speed data, and vibration data. As one more specific embodiment, the sensor data comprises main shaft speed measurements taken during turbine engine spin-down. In general, spin-down is the inertia driven rotation that occurs after the engine has been commanded to stop and fuel flow to the engine has been shut off. Specifically, after turbine engine fuel is shut off the inertia of the rotating main shaft keeps it turning. Friction forces cause the main shaft to decelerate until the inertia is completely overcome and the main shaft comes to a stop. This time between fuel flow cut off and the main shaft stopping is generally referred to as spin down. Because the fuel flow has stopped and there are no other significant forces acting on the turbine engine, the main shaft rotation speed profile during spin down is highly indicative of the state of the main shaft and/or associated bearings. Generally, it is desirable to use data from a portion of the spin down time that is most indicative of the main shaft and/or associated bearings. For example, using a speed data from the time period when the main shaft rotation is between 40% of full speed to 10% of full speed is has been shown to especially effective in detecting anomalies in the main shaft and bearings. Thus, as one specific example, main shaft speed data measurements are taken starting at 40% of full speed at a specified rate until a desired number of measurements are taken or until the engine slows to a specified point, with the results provided as sensor data in step 202. Generally, measurements taken at a rate of 1 Hz are sufficient, but higher rates can be used where such higher rate of measurements are available. Again, the measurements taken during spin down can include other types of sensor data, including exhaust gas temperature data, oil inlet pressure data, fan speed data, and vibration data. It should be noted that the sensor data received in step 202 can comprise data from one engine or from multiple engines. For example, the sensor data can comprise data taken from multiple engines on the same aircraft. In the alternative, the sensor data can comprise data taken from the same engine at multiple different occurrences. Finally, the sensor data could comprise a combination of measurements take from multiple engines at multiple different spin down occurrences. When the sensor data is taken from multiple engines, the matrix analysis is used to compare the data from different engines to detect anomalies in any of the engines. Conversely, when the sensor data is taken from a single engine during multiple occurrences, the matrix analysis compares the data from these different occurrences to detect anomalies in the engine supplying the sensor data. The next step 204 is to format the sensor data into a sensor data matrix to facilitate a matrix analysis of the sensor data. The sensor data can be formatted into a sensor data matrix in a variety of ways. For example, where the sensor data includes a measurements from multiple engines, data for each engine can be placed in a corresponding row in the sensor data matrix. Thus, for a system with 4 engines and 50 sensor data measurements per engine, the sensor data can be formatted into the sensor data matrix by forming a 4×50 matrix with 4 rows and 50 columns, with each row thus corresponding to the data from one turbine engine. In the alterative, when the sensor data comes from multiple occurrences formatting the sensor data into the sensor data matrix can comprise putting data for each occurrence into a corresponding row. For example, if sensor data comprises 60 measurements taken from six occurrences, the sensor data matrix can comprise and 6×60 with each row corresponding to one spin down occurrence of the turbine engine. It should be noted that while the terms “row” and “column” have specific mathematical connotations terms with respect to matrices, that formatting and operations performed on data in a row could equivalently be formatted and performed on data on a column, and that the terms are thus to some extent interchangeable. The next step 206 is to perform a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine. In general, the singular value analysis is designed to compare sensor data from different engines and/or different occurrences to determine if an anomaly exists in a turbine engine. For example, the singular value analysis can be used to compare spin down performance of multiple turbine engines on the vehicle to determine if any one of the engines has a problem in the main shaft and/or associated bearings. Alternatively, the singular value analysis can be used to compare spin down performance of the same engine over multiple different occurrences to determine if a problem is developing in the main shaft and/or associated bearings. In all cases, the singular value analysis provides a mechanism for comparing how close the sensor data from multiple sets of data are and hence detect anomalies in that sensor data. The step of performing a singular analysis on the sensor data matrix can be implemented with a variety of techniques and tools. For example, the singular analysis on the sensor data matrix can comprise first calculating a covariance matrix from the sensor data matrix. The covariance matrix can be calculated by multiplying the sensor data matrix by its transpose. Next, the singular values of the of the covariance matrix are calculated by any suitable technique. For example, the singular values can be calculated using a suitable QR decomposition technique for symmetric matrices. Of course, this is just one example of a technique that can be used for calculating the singular values of the matrix. Other techniques include iterative eigenvalue decomposition for solving polynomial equations. The resulting singular values are indicative of anomalies in the turbine engines. Specifically, if the sensor data from each engine and/or each occurrence is substantially equivalent, then the covariance matrix will be very close to having a single rank, and all but the first singular values will be very close to zero. If on the other hand, one or more engines and/or occurrences have significant deviations, then the second singular value will be significantly greater. Thus, the singular value analysis can comprise calculating the singular values and comparing at least one of the singular values to a threshold value that is deemed to be indicative of problems in the main shaft and/or bearings. For example, if the second singular value exceeds a threshold value then it is determined that a potential problem with the main shaft and/or bearings exists, and should be examined by a technician. The threshold value used would depend on a variety of factors. Although in theory spin down profiles from multiple engines or multiple occurrences of the same engine are similar, the rank of the resulting covariance matrix may be slightly greater than one. Consequently, the second singular value will not be exactly zero and hence one needs to set a non-zero threshold. Typically, the threshold value would be empirically derived from past experience to determine what levels of singular values are likely to be indicative problems. The lower the threshold value, the earlier such problems would be detected, at the cost of an increased number of false positives. Likewise, a higher threshold value is more likely to accurately indicate problem, at the cost of a later diction of the problems. A detailed example of an anomaly detection procedure using exemplary data sets will be given. Turning now to FIG. 3, a graph 300 illustrates exemplary main shaft speed sensor data taken from four engines during spin down. As can be seen in FIG. 3, after fuel flow is cut off, the engines decelerate as friction overwhelms the inertia of the engine. As discussed above, in the preferred system and method of anomaly detection, at least a portion of the sensor data taken during engine spin down is formatted into an appropriate sensor data matrix. Again, the portion of sensor data is preferably selected to be that portion that is most indicative of anomalies in the turbine engine. For example, the portion can be defined as a selected set of sensor data taken from each engine over a range of rotational speeds. Selecting the portion of sensor data used for each engine independently compensates for any differences in the start of the spin down between individual engines or individual occurrences. In the example of the data illustrated in FIG. 3, the portion can be defined as a specified number of samples (m), at a specified rate and beginning at a defined starting point in the spin down process for each of the four engines N1-N4. For example, starting at 40% of full engine speed and taking 80 samples at 1 Hz will define a portion of sensor data from each engine down to about 10% of full engine speed, and thus will cover the range of engine speed that has been shown to be highly indicative of main shaft and bearing related anomalies. The m samples taken from four engines N1-N4 can be formatted into a matrix NN defined as: NN = [ N 1 ( 1 ) N 1 ( 2 ) … N 1 ( m - 1 ) N 1 ( m ) N 2 ( 1 ) N 2 ( 2 ) … N 2 ( m - 1 ) N 2 ( m ) N 3 ( 1 ) N 3 ( 2 ) … N 3 ( m - 1 ) N 3 ( m ) N 4 ( 1 ) N 4 ( 2 ) … N 4 ( m - 1 ) N 4 ( m ) ] ( 1. ) In the case where all four engines are operating correctly, the data from all four engines would be very close, and the matrix defined in equation 1 would only one independent row, and hence the rank of the matrix NN would be very close to 1. If, on the other hand, one of the engines is experiencing anomalies in its main shaft and/or bearings, these anomalies will manifest themselves in the form a higher rank in the matrix. A computational tractable way of calculating the rank of the matrix is to use a singular value decomposition of the covariance matrix. The covariance matrix covNN can be defined as: covNN = 1 m - 1 NN T × NN ( 2. ) Where NNT is the transpose of the matrix NN. In the example of equation 1 with data from four engines, the covariance matrix covNN will be a 4×4 matrix with up to four non-zero singular values. Likewise, where the data is from six spin down occurrences of the same engine, the covariance matrix covNN will be a 6×6 matrix with up to six non-zero singular values. The singular values of the covariance matrix covNN can be calculated using any suitable technique. For example, they can be calculated using a tool such as the MATLAB command sigma_N=svd(NN), available in the MATLAB toolkit. With the singular values calculated they can be analyzed by comparing the singular values to a threshold value. As stated above, when an anomaly is present in the turbine engines, the second singular value of the covariance matrix will increase. The larger the anomaly, the greater the second singular value will be. Thus by analyzing the second singular value, the system and method can determine the presence of anomalies. One specific technique for determining the threshold value to use in this comparison is to examine historical data from many different sources. Turning now to FIG. 4, a histogram 400 of the logarithm of the second singular value calculated from a set of flights is illustrated. The logarithm of the second singular value is used to detect orders of magnitude change in the singular values. The histogram 400 shows how a set of historical data can be used to determine an appropriate threshold. Specifically, the histogram 400 shows that for good turbine engines, the logarithm of the second singular value consistently less than or equal to 0, whereas the smaller peak at 1 indicates the logarithm of the second singular value is greater than or equal to 1 for engines with bearing problems. Thus, 1 can serve as a threshold value for the logarithm of the second singular value. Thus, setting the threshold value for the logarithm of the second singular value using experimental data can provide good predictability of anomalies in the turbine engines. To avoid the effects of noise in the system, it is also generally preferable to require that the second singular value exceed the threshold value on more than one consecutive occasion before an alert is given to the diagnostic or control system. For example, the system can be designed to provide an alert to the system when the second singular value has exceeded the threshold value on five consecutive occurrences. This minimizes the change of noise causing a false alert to the system while providing good predictability. The anomaly detection system and method can be implemented in wide variety of platforms. Turning now to FIG. 5, an exemplary computer system 50 is illustrated. Computer system 50 illustrates the general features of a computer system that can be used to implement the invention. Of course, these features are merely exemplary, and it should be understood that the invention can be implemented using different types of hardware that can include more or different features. It should be noted that the computer system can be implemented in many different environments, such as onboard an aircraft to provide onboard diagnostics, or on the ground to provide remote diagnostics. The exemplary computer system 50 includes a processor 110, an interface 130, a storage device 190, a bus 170 and a memory 180. In accordance with the preferred embodiments of the invention, the memory system 50 includes an anomaly detection program, which includes a sensor data processor and a matrix analysis mechanism. The processor 110 performs the computation and control functions of the system 50. The processor 110 may comprise any type of processor, include single integrated circuits such as a microprocessor, or may comprise any suitable number of integrated circuit devices and/or circuit boards working in cooperation to accomplish the functions of a processing unit. In addition, processor 110 may comprise multiple processors implemented on separate systems. In addition, the processor 110 may be part of an overall vehicle control, navigation, avionics, communication or diagnostic system. During operation, the processor 110 executes the programs contained within memory 180 and as such, controls the general operation of the computer system 50. Memory 180 can be any type of suitable memory. This would include the various types of dynamic random access memory (DRAM) such as SDRAM, the various types of static RAM (SRAM), and the various types of non-volatile memory (PROM, EPROM, and flash). It should be understood that memory 180 may be a single type of memory component, or it may be composed of many different types of memory components. In addition, the memory 180 and the processor 110 may be distributed across several different computers that collectively comprise system 50. For example, a portion of memory 180 may reside on the vehicle system computer, and another portion may reside on a ground based diagnostic computer. The bus 170 serves to transmit programs, data, status and other information or signals between the various components of system 100. The bus 170 can be any suitable physical or logical means of connecting computer systems and components. This includes, but is not limited to, direct hard-wired connections, fiber optics, infrared and wireless bus technologies. The interface 130 allows communication to the system 50, and can be implemented using any suitable method and apparatus. It can include a network interfaces to communicate to other systems, terminal interfaces to communicate with technicians, and storage interfaces to connect to storage apparatuses such as storage device 190. Storage device 190 can be any suitable type of storage apparatus, including direct access storage devices such as hard disk drives, flash systems, floppy disk drives and optical disk drives. As shown in FIG. 5, storage device 190 can comprise a disc drive device that uses discs 195 to store data. In accordance with the preferred embodiments of the invention, the computer system 50 includes an anomaly detection program. Specifically during operation, the anomaly detection program is stored in memory 180 and executed by processor 110. When being executed by the processor 110, anomaly detection program receives sensor data and determines the likelihood of anomaly using the sensor data processor and the matrix analysis mechanism. As one example implementation, the anomaly detection system can operate on data that is acquired from the mechanical system (e.g., aircraft) and periodically uploaded to an internet website. The analysis is performed by the web site and the results are returned back to the technician or other user. Thus, the system can be implemented as part of a web-based diagnostic and prognostic system. As another example, the anomaly detection system can operate on board the aircraft, as part of the on-board diagnostic and fault detection system. In this case the sensor data is stored and processed on board to provide a warning when an anomaly is detected in the system. It should be understood that while the present invention is described here in the context of a fully functioning computer system, those skilled in the art will recognize that the mechanisms of the present invention are capable of being distributed as a program product in a variety of forms, and that the present invention applies equally regardless of the particular type of signal bearing media used to carry out the distribution. Examples of signal bearing media include: recordable media such as floppy disks, hard drives, memory cards and optical disks (e.g., disk 195), and transmission media such as digital and analog communication links, including wireless communication links. The present invention thus provides a system and method for detecting anomalies in turbine engines emanating from the main shaft and/or main shaft bearings. The anomaly detection system includes a sensor data processor and a matrix analysis mechanism. The sensor data processor receives engine sensor data, including main engine speed data during spin down, and formats the engine sensor data into an appropriate matrix. The matrix analysis mechanism receives the sensor data matrix and performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine main shaft and/or bearings. The output of the matrix analysis mechanism is passed to a diagnostic system where further evaluation of the anomaly detection determination can occur. The embodiments and examples set forth herein were presented in order to best explain the present invention and its particular application and to thereby enable those skilled in the art to make and use the invention. However, those skilled in the art will recognize that the foregoing description and examples have been presented for the purposes of illustration and example only. The description as set forth is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching without departing from the spirit of the forthcoming claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Modern mechanical systems can be exceedingly complex. The complexities of modern mechanical systems have led to increasing needs for automated prognosis and fault detection systems. These prognosis and fault detection systems are designed to monitor the mechanical system in an effort to predict the future performance of the system and detect potential faults. These systems are designed to detect these potential faults such that the potential faults can be addressed before the potential faults lead to failure in the mechanical system. One type of mechanical system where prognosis and fault detection is of particular importance is aircraft systems. In aircraft systems, prognosis and fault detection can detect potential faults such that they can be addressed before they result in serious system failure and possible in-flight shutdowns, take-off aborts, delays or cancellations. Modern aircraft are increasingly complex. The complexities of these aircraft have led to an increasing need for automated fault detection systems. These fault detection systems are designed to monitor the various systems of the aircraft in an effort to detect potential faults. These systems are designed to detect these potential faults such that the potential faults can be addressed before the potential faults lead to serious system failure and possible in-flight shutdowns, take-off aborts, delays or cancellations. Turbine engines are a particularly critical part of many aircraft. Turbine engines are commonly used for main propulsion aircraft. Furthermore, turbine engines are commonly used in auxiliary power units (APUs) that are used to generate auxiliary power and compressed air for use in the aircraft. Given the critical nature of turbine engines in aircraft, the need for fault detection in turbine engines is of extreme importance. Traditional fault detection systems for turbine engines have been limited in their ability to detect the occurrence of anomalies in the bearings and main shaft of the turbine engine. Deformations in the shaft can lead to problems in the bearings, and likewise, problems in the bearings can lead to failures in the shaft. In all cases, defects in the shaft and/or bearings can cause severe performance problems in the turbine engines. Unfortunately, detection methods have been unable to suitably detected anomalies in the main shaft and bearings with sufficient accuracy based on the limited data sets available for fault detection. Thus, what is needed is an improved system and method for detecting anomalies in turbine engine main shafts and bearings that can consistently detect anomalies and the problems that result from limited data sets.
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<SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The present invention provides a system and method for detecting anomalies in turbine engines emanating from the main shaft and/or main shaft bearings. The anomaly detection system includes a sensor data processor and a matrix analysis mechanism. The sensor data processor receives engine sensor data, including main engine speed data during spin down, and formats the engine sensor data into an appropriate matrix. The matrix analysis mechanism receives the sensor data matrix and performs a singular value analysis on the sensor data matrix to detect potential anomalies in the turbine engine main shaft and/or bearings. The output of the matrix analysis mechanism is passed to a diagnostic system where further evaluation of the anomaly detection determination can occur.
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20040628
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20080506
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20051229
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94544.0
| 0
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LAU, TUNG S
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SYSTEM AND METHOD FOR TURBINE ENGINE ANOMALY DETECTION
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,880,112
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ACCEPTED
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Grid computing on radiology network
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A grid computing system and method is provided for medical data processing. The grid computing system comprises a software infrastructure, and an imaging device capable of interfacing with the software infrastructure over a distributed electronic network. Also included is a plurality of CPUs capable of interfacing with the software infrastructure over the network. The performance of the plurality of CPUs is dependent on balancing load. A large medical dataset is split onto several processing nodes of the plurality of CPUs, respectively, such that performance and power is increased. In the grid computing method, a grid is limited to a nuclear medicine or radiology network. A tight and easy configuration management of computing nodes, and a tight load balancing between standardized nodes are provided. An existing network of CPUs is utilized, such that the greatest benefit is provided at the lowest cost.
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1. A grid computing system comprising: a software infrastructure; an imaging device capable of interfacing with said software infrastructure over a distributed electronic network; and a plurality of central processing units (CPUs) capable of interfacing with said software infrastructure over the network, performance of said plurality of CPUs being dependent on balancing load, wherein a large medical dataset is split onto several processing nodes of said plurality of CPUs, respectively, such that performance and power is increased. 2. The grid computing system of claim 1, wherein said software infrastructure is based on Windows NT7 operating system with a graphical user interface. 3. The grid computing system of claim 1, wherein said imaging device is a combined imaging apparatus having at least two different imaging modalities. 4. The grid computing system of claim 3, wherein said combined imaging apparatus is a positron emission tomography/computed tomography (PET-CT) imaging device. 5. The grid computing system of claim 3, wherein said combined imaging apparatus is a single photon emission computed tomography/computed tomography (SPECT-CT) imaging device. 6. The grid computing system of claim 1, wherein said imaging device is a single scanning device. 7. The grid computing system of claim 6, wherein said single scanning device is a SPECT, PET, single photon planar, or X-ray imaging devices. 8. The grid computing system of claim 1, wherein said plurality of CPUs consists of clusters and networks of workstations. 9. The grid computing system of claim 1, wherein said plurality of CPUs consists of clusters and networks of personal computers. 10. The grid computing system of claim 1, wherein said plurality of CPUs consists of a combination of clusters and networks of workstations and of personal computers. 11. A method of processing medical data, comprising the steps of: limiting a computing network grid to a nuclear medicine or radiology network; providing a tight configuration management of computing nodes; providing a tight load balancing between standardized nodes; and utilizing an existing network of central processing units (CPUs) to process nuclear medical image data under said configuration management and load balancing parameters. 12. The method of claim 11, wherein said network of CPUs consists of clusters and networks of workstations. 13. The method of claim 11, wherein said network of CPUs consists of clusters and networks of personal computers. 14. The method of claim 11, wherein said network of CPUs consists of a combination of clusters and networks of workstations and of personal computers. 15. The method of claim 14, wherein each workstation and personal computer can be both a processing node to serve other workstations, or personal computer in a grid.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to medical imaging and, more particularly, to a system and method of processing medical images. 2. Description of the Background Art Medical imaging is one of the most useful diagnostic tools available in modern medicine. Medical imaging allows medical personnel to non-intrusively look into a living body in order to detect and assess many types of injuries, diseases, conditions, etc. Medical imaging allows doctors and technicians to more easily and correctly make a diagnosis, decide on a treatment, prescribe medication, perform surgery or other treatments, etc. There are medical imaging processes of many types and for many different purposes, situations, or uses. They commonly share the ability to create an image of a bodily region of a patient, and can do so non-invasively. Examples of some common medical imaging types are nuclear imaging, magnetic resonance imaging (MRI), ultrasound, X-rays, tomography of various types, etc. Using these or other imaging types and associated machines, an image or series of images may be captured. Other devices may then be used to process the image in some fashion. Finally, a doctor or technician may read the image in order to provide a diagnosis. The image may capture various details of the subject, which may include bones, organs, tissues, ducts, blood vessels, nerves, previous surgical artifacts such as implants or scar tissue, etc. The image or images may be two-dimensional (i.e., planar) or three-dimensional. In addition, the image capture may produce an image sequence or video that shows live operation, such as a functioning organ, for example. An imaging machine may capture an image, manipulate it, process it in some fashion in order to improve the image, display it to a doctor or technician, and store it for later use. Computerized image processing generally requires that the image data conform to some sort of protocol, with the protocol being a set of rules and standards that ensure that the information may be efficiently communicated and manipulated among different apparatus. The Digital Imaging and Communications in Medicine (DICOM) standard provides a well-defined and accepted data format and interaction protocol for communicating a processing medical image data, and is incorporated herein by reference. The DICOM standard is available from the Radiological Society of North America, Oak Brook, Ill. 60523-2251. The DICOM standard has become popular for medical imaging because it ensures that conforming machines can operate on image data communicated from other conforming machines. Machines that may employ the DICOM standard may be workstations, CT scanners, MR images, film digitizers, shared archives (storage devices), printers, and other devices that may be used to process and store image and patient data. FIG. 1 shows a conventional medical imaging system 100. The medical imaging system 100 may include an imager 107 and imager controller 106 (they may be an integrated device), a patient database 110, an output device 115, a scanner 117, and one or more workstations 122. The imager 107 and imager controller 106 capture an image or images of a patient. The imager 107 may be, for example, a gamma ray camera, an X-ray imager, a magnetic resonance imager (MRI), an ultrasound imager, etc. The patient database 110 may store patient information (i.e., a plurality of records containing a name, vital parameters, a doctor, medical conditions, etc.), and imaging data. The output device 115 may be, for example, a printer, a computer monitor or other display screen, a film developer, etc. The scanner 117 may be a scanning device that digitizes an image. The workstations 122 may be used to access the patient database 110 in order to add or retrieve data. Patient information might also be stored in local databases on the processing workstations. In that case, the patient database 110 acts as a data repository for storage. The various components may be connected by a distributed electronic network 103, such as, for example, a local area network (LAN), a wide area network (WAN), a virtual private network (VPN), or the Internet. The individual components may therefore be located in separate rooms, floors, buildings, or even separate hospitals, clinics or institutions (such as research centers that are not hospitals). Computerized image processing is well known in the art. However, the need for computing power is ever increasing. For example, recent developments in tomographic reconstruction processes require more and more computing power to more accurately model the physics of image formation. Current processing software memory and processing power requirements may already exceed the specifications of the most powerful computers currently available on the market. As an example, in the field of SPECT imaging, the OSEM 3D reconstruction algorithm currently requires several hours of processing time to process a 256-cube volume, and is therefore not usable in a clinical practice. The processing power requirement is projected to only increase as scanners produce more and more data as resolution and speed increase, and as interest grows in obtaining full resolution co-registered or fused images from different modalities, such as SPECT-CT, PET-CT, SPECT-MRI, etc. Accordingly, there exists a present need in the art to reduce overall radiological image processing time. SUMMARY OF THE INVENTION The present invention is provided to solve the above-mentioned problem. According to an aspect of the present invention, there is provided a grid computing system. The grid computing system comprises a software infrastructure, and an imaging device capable of interfacing with the software infrastructure over a distributed electronic network. Also included is a plurality of central processing unit (CPU) workstations capable of interfacing with the software infrastructure over the network. The performance of the plurality of CPUs is dependent on properly balancing load. A large dataset of medical images are split onto several processing nodes of the plurality of CPUs, respectively, such that performance and power is increased. According to another aspect of the present invention, there is provided a method of grid computing. In the method of the present invention, a grid is limited to a nuclear medicine or radiology network. A tight and easy configuration management of computing nodes, and a tight load balancing between standardized nodes are provided. An existing network of central processing units (CPUs) is utilized, such that the greatest benefit is provided at the lowest cost. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: FIG. 1 is a conventional medical imaging system; FIG. 2 shows the grid computing system according to an exemplary embodiment of the present invention; and FIG. 3 is a flow chart of the method of grid computing according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As illustrated in FIG. 2, the grid computing system 20 comprises a master processing workstation 202, an imaging device 204, and a plurality of computing nodes 2061-206n. In accordance with the principle of a computing “grid,” each workstation is/can be both master and computing node. The imaging device 204 and the plurality of computing nodes 2061-206n interface with the master processing workstation 202 over a network such as, for example, a local area network (LAN), a wide area network (WAN), a virtual private network (VPN), the Internet, or the like. According to one particular example embodiment of the invention, the master processing workstation 202 may be based on the universally accepted Windows NT7 operating system with a graphical user interface (GUI) that is simple and intuitive. However, the invention is not restricted to any particular operating system or platform, but works on any platform or operation system. Referring to FIG. 2, the imaging device 204 may be a combined scanning device, such as, for example, positron emission tomography/computed tomography (PET-CT), single photon emission computed tomography/computed tomography (SPECT-CT), or the like. It will be appreciated by those skilled in the art that the imaging device 204 also can be a single imaging device such as, for example, SPECT, planar imaging, or PET or MRI or Ultrasound or any other type of data collecting device. The plurality of computing nodes 2061-206n can be clusters and networks of workstations interfacing with the master processing workstation 202 over the network, clusters and networks of personal computers interfacing with the master processing workstation 202 over the network, or a combination of clusters and networks of workstations and of personal computers interfacing with the master processing workstation 202 over the network. Accordingly, multimodality images can be viewed on the computing nodes 2061-206n alongside CT, MR, ultrasound, NM, angiography images, or the like. The computing nodes 2061-206n allow access to a universe of information and provide unlimited functionality. Performance of the plurality of computing nodes 2061-206n is dependent on the ability to balance load, and maintain parallel processing software infrastructure (e.g., versions, updates, software, hardware obsolescence, etc.). In the parallel processing method of the present invention, a large medical dataset is split onto several processing nodes. The acceleration ratios obtained are usually equal to the number of computing nodes. It is noted that the medical dataset is not limited to images. The benefit of more computing power allows one to consider processing raw information from the scanner before it is actually formatted into images, for example, list mode processing in nuclear medicine carries out processing on count data in the form of a sequential list of numerical values. When demand processing is performed on the cluster of processing nodes 2061-206n, significant and sustainable computer power improvement is achieved (e.g., maximum performance and reliability). Alternatively, when reconstruction load is spread on clusters and networks of workstations and personal computers 2061-206n, good performance is achieved. Users such as research sites can mix the workstations and personal computers 2061-206n to achieve the highest demand of computing power. FIG. 3 is a flow chart of a method of grid computing according to an exemplary embodiment of the present invention. In step S301, a network grid is limited to a nuclear medicine or radiology network. This has the beneficial effect of reserving the computing power for those applications that require the most intensive processing. In step S303, a tight and easy configuration management of computing nodes is provided, and a tight load balancing between standardized nodes is also provided (step S305). An existing network of central processing units (CPUs) is utilized in step S307, such that the greatest benefit is provided at the lowest cost (eq., cycles on idle machines are not wasted). The grid computing system and method as described herein provide several benefits such as increased performance and power (e.g., maximum performance and reliability). While a preferred embodiment of the present invention has been described above, it should be understood that it has been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by the above described exemplary embodiment. Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described herein.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to medical imaging and, more particularly, to a system and method of processing medical images. 2. Description of the Background Art Medical imaging is one of the most useful diagnostic tools available in modern medicine. Medical imaging allows medical personnel to non-intrusively look into a living body in order to detect and assess many types of injuries, diseases, conditions, etc. Medical imaging allows doctors and technicians to more easily and correctly make a diagnosis, decide on a treatment, prescribe medication, perform surgery or other treatments, etc. There are medical imaging processes of many types and for many different purposes, situations, or uses. They commonly share the ability to create an image of a bodily region of a patient, and can do so non-invasively. Examples of some common medical imaging types are nuclear imaging, magnetic resonance imaging (MRI), ultrasound, X-rays, tomography of various types, etc. Using these or other imaging types and associated machines, an image or series of images may be captured. Other devices may then be used to process the image in some fashion. Finally, a doctor or technician may read the image in order to provide a diagnosis. The image may capture various details of the subject, which may include bones, organs, tissues, ducts, blood vessels, nerves, previous surgical artifacts such as implants or scar tissue, etc. The image or images may be two-dimensional (i.e., planar) or three-dimensional. In addition, the image capture may produce an image sequence or video that shows live operation, such as a functioning organ, for example. An imaging machine may capture an image, manipulate it, process it in some fashion in order to improve the image, display it to a doctor or technician, and store it for later use. Computerized image processing generally requires that the image data conform to some sort of protocol, with the protocol being a set of rules and standards that ensure that the information may be efficiently communicated and manipulated among different apparatus. The Digital Imaging and Communications in Medicine (DICOM) standard provides a well-defined and accepted data format and interaction protocol for communicating a processing medical image data, and is incorporated herein by reference. The DICOM standard is available from the Radiological Society of North America, Oak Brook, Ill. 60523-2251. The DICOM standard has become popular for medical imaging because it ensures that conforming machines can operate on image data communicated from other conforming machines. Machines that may employ the DICOM standard may be workstations, CT scanners, MR images, film digitizers, shared archives (storage devices), printers, and other devices that may be used to process and store image and patient data. FIG. 1 shows a conventional medical imaging system 100 . The medical imaging system 100 may include an imager 107 and imager controller 106 (they may be an integrated device), a patient database 110 , an output device 115 , a scanner 117 , and one or more workstations 122 . The imager 107 and imager controller 106 capture an image or images of a patient. The imager 107 may be, for example, a gamma ray camera, an X-ray imager, a magnetic resonance imager (MRI), an ultrasound imager, etc. The patient database 110 may store patient information (i.e., a plurality of records containing a name, vital parameters, a doctor, medical conditions, etc.), and imaging data. The output device 115 may be, for example, a printer, a computer monitor or other display screen, a film developer, etc. The scanner 117 may be a scanning device that digitizes an image. The workstations 122 may be used to access the patient database 110 in order to add or retrieve data. Patient information might also be stored in local databases on the processing workstations. In that case, the patient database 110 acts as a data repository for storage. The various components may be connected by a distributed electronic network 103 , such as, for example, a local area network (LAN), a wide area network (WAN), a virtual private network (VPN), or the Internet. The individual components may therefore be located in separate rooms, floors, buildings, or even separate hospitals, clinics or institutions (such as research centers that are not hospitals). Computerized image processing is well known in the art. However, the need for computing power is ever increasing. For example, recent developments in tomographic reconstruction processes require more and more computing power to more accurately model the physics of image formation. Current processing software memory and processing power requirements may already exceed the specifications of the most powerful computers currently available on the market. As an example, in the field of SPECT imaging, the OSEM 3D reconstruction algorithm currently requires several hours of processing time to process a 256-cube volume, and is therefore not usable in a clinical practice. The processing power requirement is projected to only increase as scanners produce more and more data as resolution and speed increase, and as interest grows in obtaining full resolution co-registered or fused images from different modalities, such as SPECT-CT, PET-CT, SPECT-MRI, etc. Accordingly, there exists a present need in the art to reduce overall radiological image processing time.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is provided to solve the above-mentioned problem. According to an aspect of the present invention, there is provided a grid computing system. The grid computing system comprises a software infrastructure, and an imaging device capable of interfacing with the software infrastructure over a distributed electronic network. Also included is a plurality of central processing unit (CPU) workstations capable of interfacing with the software infrastructure over the network. The performance of the plurality of CPUs is dependent on properly balancing load. A large dataset of medical images are split onto several processing nodes of the plurality of CPUs, respectively, such that performance and power is increased. According to another aspect of the present invention, there is provided a method of grid computing. In the method of the present invention, a grid is limited to a nuclear medicine or radiology network. A tight and easy configuration management of computing nodes, and a tight load balancing between standardized nodes are provided. An existing network of central processing units (CPUs) is utilized, such that the greatest benefit is provided at the lowest cost.
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20040629
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20121009
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20051229
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96289.0
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TRUONG, LAN DAI T
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GRID COMPUTING ON RADIOLOGY NETWORK
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UNDISCOUNTED
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ACCEPTED
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10,880,180
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ACCEPTED
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Structured document processor
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A structured document processor includes a template storing module for storing a template, a template selection accepting module for accepting selection of a template, a template structure analyzing module for analyzing the structure of a template, a content area selection accepting module for accepting selection of a content area, a document storing module for a storing document, a document selection accepting module for accepting selection of a document, a document structure analyzing module for analyzing the structure of a document, a structural component selection accepting module for accepting selection of a structural component, an application method storing module for storing a selected content area and selected structural component, a document structure checking module for checking validity of insertion of a structural component into a content area from a structural viewpoint of the document, a structural component retrieving module for retrieving a structural component similar to a selected structural component from structural components of other documents, and a template applying module for applying a template.
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1. A structured document processor comprising: a structural component selection accepting module for accepting selection of a particular structural component among multiple structural components composing a predetermined document; and a template applying module for inserting the particular structural component, selection of which has been accepted by the structural component selection accepting module, into a predetermined content area included in a predetermined template. 2. The structured document processor according to claim 1, further comprising a content area selection accepting module for accepting selection of the predetermined content area, into which the particular structural component is to be inserted, from among content areas included in the predetermined template. 3. The structured document processor according to claim 1, further comprising a document structure checking module for checking whether insertion of the particular structural component, selection of which has been accepted by the structural component selection accepting module, into the predetermined content area is valid from a structural viewpoint of the document. 4. The structured document processor according to claim 1, further comprising a structural component retrieving module for retrieving a structural component positioned similarly to the particular structural component, selection of which has been accepted by the structural component selection accepting module, from among structural components composing another document different from the predetermined document, wherein the template applying module inserts the structural component retrieved by the structural component retrieving module into the predetermined content area. 5. The structured document processor according to claim 4, wherein the structural component retrieving module, if not finding a structural component positioned similarly to the particular structural component, selection of which has been accepted by the structural component selection accepting module, retrieves a structural component positioned similarly to a different higher-level structural component than the predetermined structural component, from among structural components composing the different document. 6. The structured document processor according to claim 5, wherein the structural component retrieving module determines whether insertion of the different structural component into the predetermined content area is valid from a structural viewpoint of the document, and retrieves a structural component positioned similarly to the different structural component from among structural components composing the different document. 7. A structured document processor comprising: a document structure displaying module for displaying the structure of a predetermined document; and an application result displaying module for displaying the result of inserting the particular structural component into a predetermined content area included in a predetermined template in response to selection of a particular structural component among multiple structural components included in the structure displayed by the document structure displaying module. 8. The structured document processor according to claim 7, further comprising a content area information displaying module for displaying information about content areas included in the predetermined template, wherein the application result displaying module displays the result of inserting the particular structural component into a content area corresponding to the particular information in response to selection of particular information among the information displayed by the content area information displaying module. 9. A method for processing a structured document comprising: accepting selection of a particular structural component among multiple structural components composing a predetermined document stored in predetermined storing module; and inserting the particular structural component, selection of which has been accepted, into a predetermined content area included in a predetermined template stored in predetermined storing module. 10. The method according to claim 9, further comprising accepting selection of the predetermined content area, into which the particular structural component is to be inserted, from among content areas included in the predetermined template. 11. The method according to claim 9, further comprising: generating first structure information showing the structure of the predetermined template; generating second structure information showing the structure of the predetermined document; and checking whether insertion of the particular structural component, selection of which has been accepted, into the predetermined content area is valid from a structural viewpoint of the document, based on the first and second structure information. 12. The method according to claim 9, further comprising: generating third structure information showing the structure of the different document different from the predetermined document; retrieving a structural component positioned similarly to the particular structural component, selection of which has been accepted, from among structural components included in the third structure information; and inserting the retrieved structural component into the predetermined content area. 13. The method according to claim 12, wherein retrieving a structural component positioned similarly to the particular structural component, selection of which has been accepted, from among structural components included in the third structure information comprises determining whether there exists a structural component positioned similarly to the particular structural component, selection of which has been accepted, in the structural components included in the third structure information, and wherein no structural component is positioned similarly, further comprising temporarily changing the particular structural component to a different higher-level structural component than the particular structural component, and retrieving a structural component positioned similarly to the different structural component, from among structural components included in the third structure information. 14. The method according to claim 13 further comprising determining whether insertion of the different structural component into the particular content area is valid from a structural viewpoint of the document, and, if it is determined to be valid, a structural component positioned similarly to the different structural component is retrieved from among structural components included in the third structure information. 15. A computer program product for processing a structural document, the computer program product comprising: a computer readable medium having computer readable program code embodied therein, the computer readable program code comprising: computer readable program code configured to accept selection of a particular structural component among multiple structural components composing a predetermined document; and computer readable program code configured to insert the particular structural component, selection of which has been accepted, into a predetermined content area included in a predetermined template. 16. The computer program product according to claim 15, further comprising computer readable program code configured to accept selection of the predetermined content area, into which the particular structural component is to be inserted, from among content areas included in the predetermined template. 17. The computer program product according to claim 15, further comprising computer readable program code configured to check whether insertion of the particular structural component, selection of which has been accepted, into the predetermined content area is valid from a structural viewpoint of the document. 18. The computer program product according to claim 17, further comprising computer readable program code configured to retrieve a structural component positioned similarly to the particular structural component, selection of which has been accepted, from among structural components composing different document different from the predetermined document and computer readable program code configured to insert the retrieved structural component into the predetermined content area. 19. The computer program product according to claim 18, further comprising computer readable program code configured to determine whether there exists a structural component positioned similarly to the particular structural component, selection of which has been accepted, in structural components composing the different document; and wherein no structural component positioned similarly, further comprising computer readable program code configured to retrieve a structural component positioned similarly to a different higher-level structural component than the predetermined structural component, from among structural components composing the different document. 20. The computer program product according to claim 19, further comprising computer readable program code configured to determine whether insertion of the different structural component into the predetermined content area is valid from a structural viewpoint of the document, and if it is determined to be valid, computer readable program code configured to retrieve a structural component positioned similarly to the different structural component from among structural components composing the different document.
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BACKGROUND OF THE INVENTION The present invention relates to a structured document processor for processing a structured document composed of one or multiple structural components, and in particular, to a structured document processor for applying a template to a structured document. There are a number of websites available on the Internet including commercial websites and private websites. Commercial websites typically have elaborate web pages for the purpose of attracting customers. In addition, the web pages may include a uniform design. For example, one format that may be used is a menu list located at the left side of the web pages and a bar with a logo of a company at the top of the web pages. If the logo of the company is changed, all the web pages included in the website have to be corrected. In the case of a big company, thousands or many thousands of web pages may have to be edited. This requires a great amount of work. BRIEF SUMMARY OF THE INVENTION According to one aspect of the present invention, a structured document processor comprises a structural component selection accepting module for accepting selection of a particular structural component among multiple structural components composing a predetermined document, and a template applying module for inserting the particular structural component, selection of which has been accepted by the structural component selection accepting module, into a predetermined content area included in a predetermined template. According to another aspect of the present invention, a method for processing a structured document comprises accepting selection of a particular structural component among multiple structural components composing a predetermined document stored in predetermined storing module, and inserting the particular structural component, selection of which has been accepted, into a predetermined content area included in a predetermined template stored in predetermined storing module. According to yet another aspect of the present invention, a computer program product for processing a structural document comprises a computer readable medium having computer readable program code embodied therein. The computer readable program code comprises computer readable program code configured to accept selection of a particular structural component among multiple structural components composing a predetermined document, and computer readable program code configured to insert the particular structural component, selection of which has been accepted, into a predetermined content area included in a predetermined template. Other aspects and features of the present invention, as defined solely by the claims, will become apparent to those ordinarily skilled in the art upon review of the following non-limited detailed description of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a block diagram showing one aspect of the present invention; FIG. 2 is a flowchart showing the operation of applying a template to a single document; FIG. 3 is a flowchart showing the operation of applying a template to another document; FIG. 4 describes a document according to one aspect of the present invention; FIG. 5 describes a document according to another aspect of the present invention; FIG. 6 describes a document according to yet another aspect of the present invention; FIG. 7 describes a template according to one aspect of the present invention; FIG. 8 shows an example of a screen according to one aspect of the present invention; FIG. 9 shows an example of a screen according to another aspect of the present invention; FIG. 10 shows an example of a screen according to yet another aspect of the present invention; FIG. 11 shows an example of a screen according to a further aspect of the present invention; FIG. 12 shows an example of the stored contents; FIG. 13 shows a document before application of the template and a document after application of the template; FIG. 14 shows an example of a screen according to a still further aspect of the present invention; and FIG. 15 shows an example of a screen according to an aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION As will be appreciated by one of skill in the art, the present invention may be embodied as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Furthermore, the present invention may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium. Any suitable computer readable medium may be utilized. The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a nonexhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a transmission media such as those supporting the Internet or an intranet, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. Computer program code for carrying out operations of the present invention may be written in an object oriented programming language such as Java7, Smalltalk or C++. However, the computer program code for carrying out operations of the present invention may also be written in conventional procedural programming languages, such as the “C” programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user=s computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user=s computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). The present invention is described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create module for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction module which implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. It has been devised to apply a template (model document) to a structured document such as an HTML document realizing a web page. A template is such or provide a uniform layout of a document. It is a model document in which two kinds of areas are specified: an area to be used in common among multiple documents to which the template is applied and an area to be used for freely setting or editing different contents according to documents to which the template is applied (hereinafter referred to as a “content area”). Management of web pages using a template allows, even in the case of change of a logo of a company and the like, all the web pages to which the template is applied to be automatically corrected only by rewriting a file (template) including the logo. In the Published Unexamined Patent Application No. 2001-209641 (pp. 10-22; FIGS. 2 to 9), a document composition process is performed by extracting document components from a structured document and inserting or substituting each of the document components in a template. However, it is necessary to embed a label in a one-to-one correspondence to each of a template and a structured document, and it is impossible to use a general-purpose template or apply a template to a structured document without a label embedded therein. There is provided a product for assisting application of a template to a document, such as a HTML document, when creating a web page. However, the following restrictions are imposed on use of such a product: the first restriction is that a portion to be inserted in the content area can be specified only for the entire document; the second is that a document can be inserted into only one content area even if there are multiple content areas in a template; and the third is that a template can be applied to only one document and cannot be applied to multiple documents at the same time. As shown in FIG. 1, a structured document processor 10 is provided with a template storing module 11, a template selection accepting module 12, a template structure analyzing module 13, a content area selection accepting module 14, a document storing module 15, a document selection accepting module 16, a document structure analyzing module 17, a structural component selection accepting module 18, an application method storing module 19, a document structure checking module 20, a template applying module 21 and a structural component retrieving module 22. The template storing module 11 is a module for storing a structured document used as a template (hereinafter, simply referred to as a “template”) and the template selection accepting module 12 is a module for accepting information identifying a template selected by a user. The template structure analyzing module 13 is a module for analyzing the document structure of a specified template, and the content area selection accepting module 14 is a module for accepting selection of a particular content area among content areas in a template. The document storing module 15 is a module for storing a structured document to which a template is to be applied (hereinafter, simply referred to as a “document”) and the document selection accepting module 16 is a module for accepting information identifying a document selected by a user. The document structure analyzing module 17 is a module for analyzing the structure of a specified document, and the structural component selection accepting module 18 is a module for accepting selection of a particular structural component among structural components composing a document. The application method storing module 19 is a module for storing information about a content area for which selection has been accepted by the content area selection accepting module 14 and information about a structural component for which selection has been accepted by the structural component selection accepting module 18 in association with each other. The document structure checking module 20 is a module for checking whether insertion of a specified structural component into a specified content area is valid from a structural viewpoint of the document. The template applying module 21 is a module for applying a template on a memory. The structural component retrieving module 22 is a module for retrieving a structural component similar to a structural component stored in the application method storing module 19 from among structural components included in the result of analysis by the document structure analyzing module 17. A hardware configuration similar to that for a general computer system may be adopted for a structured document processor according to one embodiment. That is, any configuration may be adopted using a central processing unit (CPU) and a main memory, which may be connected to an auxiliary storage device via a bus. The auxiliary storage may comprise a hard disk, flexible disk, MO (magneto-optical disk), CD-ROM and the like. A computer program for realizing this embodiment may be stored in the auxiliary storage device. By the central processing unit (CPU) reading the computer program into the main memory and executing it, there is realized each of the template selection accepting module 12, the template structure analyzing module 13, the content area selection accepting module 14, the document selection accepting module 16, the document structure analyzing module 17, the structural component selection accepting module 18, the document structure checking module 20, the template applying module 21 and the structural component retrieving module 22. Each of the template storing module 11, the document storing module 15 and the application method storing module 19 may be realized with the use of the auxiliary storage device or with the use of the main memory. Referring also to FIG. 3, if it is not determined that there is any appropriate structural component, then the structural component included in the association information which is stored in the application method storing module 19 is changed to a higher-level structural component (step 304) (hereinafter, such change of a structural component is referred to as “expansion”). The structural component retrieving module 22 determines whether the expansion is valid from a structural viewpoint of the document (step 305). If the expansion is not valid from a structural viewpoint of the document, then the process returns to step 304 and tries expansion of the structural component range again. If the expansion is valid from a structural viewpoint of the document, the process proceeds to step 303, where it is determined whether there is any structural component positioned similarly to the structural component after expansion, among structural components included in the result of the analysis by the document structure analyzing module 17 (step 303). If it is determined that there is any appropriate structural component at step 303, then information about association between information about a content area and information about the structural component (information indicating which structural component should be inserted into which content area in the new document) is retained, and it is determined whether retrieval of a structural component to be inserted has been performed for all the content areas (step 306). If it is not determined that retrieval has been performed for all the content areas, then steps 303 to 305 are performed for the other content areas. If it is determined that retrieval has been performed for all the content areas, then the process proceeds to step 307. Eventually, the template applying module 21 applies the template on a memory based on the information about a structural component to be inserted for all the content areas (step 307). The operation of one embodiment will be described below in detail using a specific example. In this specific example, documents shown in FIGS. 4 to 6 will be used as those to which a template is applied. In FIGS. 4 to 6, a display image of a document is shown on the left side. That is, it is assumed that an HTML document which realizes such a display is stored in the document storing module 15. In FIGS. 4 to 6, the structure of the document is also shown on the right side. However, it is assumed that the structure of the document is to be generated by the document structure analyzing module 17 when the document is selected, as described later. In the document shown in FIG. 4 (“index.html”), an area 401 corresponds to <TABLE> 411; an area including areas 402 to 404 corresponds to <TABLE> 412; and the areas 402, 403 and 404 correspond to <TD> 413, 414 and 415, respectively. In the document shown in FIG. 5 (“page2.html”), an area 501 corresponds to <TABLE> 511; an area including areas 502 and 503 corresponds to <TABLE> 512; and the areas 502 and 503 correspond to <TD> 513 and 514, respectively. In the document (“page3.html”) shown in FIG. 6, an area 601 corresponds to <TABLE> 611, and an area 602 corresponds to <TABLE> 612 as a frame and to <TD> 613 as content. In this specific example, a template shown in FIG. 7 will be used as a template applied to the above-mentioned documents. In FIG. 7, a display image of the template is shown on the left side. That is, it is assumed that an HTML document which realizes such a display is stored in the template storing module 11. In FIG. 7, the document structure of the template is also shown on the right side. However, it is assumed that the document structure of the template is to be generated by the template structure analyzing module 13 when the template is selected, as described later. In the template shown in FIG. 7 (“template.htpl”), an area 701 corresponds to <TABLE> 711; an area including areas 702 to 704 corresponds to <TABLE> 712; the areas 702, 703 and 704 correspond to <TD> 713, 714 and 716, respectively; and an area 705 corresponds to <TABLE> 717. The template also includes information indicating content areas. This information can be realized as a special tag put in an HTML tag, for example. In the example in FIG. 7, a special tag <tpl:insert> 715 is put in an HTML tag <td> to indicate that the area 703 corresponding to the <TD> 714 is a content area. Furthermore, identification information such as the name of the content area is also described in the tag 715, though it is not shown in FIG. 7. On the assumption of the description above, specific description will be made on the operation of applying a template to a single document shown in the flowchart in FIG. 2. The document preselection step may be executed in advance to select some documents to which the template is to be applied, from among a lot of documents that exist in the structured document processor and store them in the document storing module 15. It is assumed here that the above-mentioned documents “index.html”, “page2.html” and “page3.html” are stored in the document storing module 15 via such a processing. The process shown in FIG. 2 is then started. The screen image at the start of the process is shown in FIG. 8. On the screen in FIG. 8, either a sample template or a user-defined template can be specified as a template type. A user-defined template is specified here, as shown in the figure. A thumbnail of a selectable template “template.htpl” is then displayed in the lowest area. Though only one template is displayed since only one template is assumed in this specific example, multiple thumbnails are displayed when multiple templates are assumed. If the user clicks the thumbnail of the “template.htpl”, the location of the template “/WebContent/theme” and its file name “template.htpl” are displayed on the area immediately above the thumbnail, and information identifying the selected template is sent to the structured document processor. In response to this, the template selection accepting module 12 accepts the information (step 201). At this point of time, the template structure analyzing module 13 analyzes the structure of the selected template (step 202), though it is not shown on the screen display. Specifically, there is generated information about the document structure of the template, which is shown on the right side of FIG. 7. After or in parallel with the processing at step 202, there is displayed a screen for specifying which structural components should be inserted in which content areas in the selected template (a screen in a format shown in FIGS. 9 to 11). There is included information indicating that a content area “main” exists in the template “template.htpl”, in the document structure of the template generated by the template structure analyzing module 13 at step 202, so that the “main” is displayed as a selectable content area when the screen is initially displayed. Though only one content area name is displayed since a template with only one content area is used in this specific example, multiple content area names are displayed if a template with multiple content areas is used. The user first specifies which document the template is to be applied to on this screen. FIG. 9 shows the screen image to be displayed then. By clicking the downward triangle mark at the right end of the area surrounded by a heavy line in FIG. 9, information for identifying selectable documents (“/WebContent/index.html”, “/VWebContent/page2.html” and “WebContent/page3.html”) is displayed, and “/WebContent/index.html” is selected here as shown in the figure. A preview image of the selected document is displayed in the lower left area, as indicated by a “Preview” arrow, and information identifying the selected document is sent to the structured document processor. In response to this, the document selection accepting module 16 accepts the information (step 203). At this point, the document structure analyzing module 17 analyzes the structure of the selected document, though it is not shown on the screen display (step 204). Specifically, there is generated information about the document structure, which is shown on the right side of FIG. 4. Furthermore, information about structural components composing the document “index.html” is included in the document structure, which is the result of analysis by the document structure analyzing module 17, so that the information about structural components composing the document “index.html” is displayed in the area on the right in the middle. Only the structural component in the highest-level hierarchy is displayed in the initial display. The user then selects a content area to which a structural component should be inserted. The screen image at this point of time is shown in FIG. 10. The content area “main” is selected in the area surrounded by a heavy line in FIG. 10. Information identifying the selected content area is then sent to structured document processor, and the content area selection accepting module 14 accepts the information (step 205). The user then selects a structural component to be inserted in the selected content area from a tree indicating the document structure. FIG. 11 shows the screen image to be displayed then. By sequentially following <BODY>, the second <TABLE> thereunder, the first <TBODY> thereunder, and then the first <TR> thereunder in the area surrounded by a heavy line in FIG. 11, there is provided a screen display as shown in the figure. The second <TD> under <TR>, that is, the <TD> 414 in FIG. 4 is selected here, as shown in the figure. Information identifying the selected structural component is then sent to the structured document processor, and the structural component selection accepting module 18 accepts the information (step 206). In this specific example, since there is only one content area that exists in the template “template.htpl” and there is no unprocessed content area (YES at step 207), the document structure checking module 20 then determines whether insertion of the structural component <TD> 414 into the content area “main” in the template “template.htpl” is valid from a structural viewpoint of the document (step 208). It is determined that the insertion is valid from a structural viewpoint of the document here by a processing to be described later, so that the template applying module 21 applies the template, and a preview as shown in the lower right area in FIG. 11 is displayed (step 209). In this embodiment, the information about association between the information about the content area selected at step 205 and the information about the structural component selected at step 206 is stored in the application method storing module 19, and FIG. 12 shows an example thereof. In FIG. 12, the name of a content area is stored as information about the content area. As information about a structural component, information about the document structure excluding structural components in the document structure which are not passed to reach the structural component. However, this is only an example, and any information may be stored only if it can identify which structural component has been inserted in which content area. For example, template structure information including the content area information may be stored as the content area information, instead of the name of the content area. The validity check from a structural viewpoint of the document at step 208 is performed as follows. First, by referring to the result of the analysis of the template structure by the template structure analyzing module 13, the document structure checking module 20 recognizes that the content area “main” is a content area put in <TD>. Furthermore, by referring to the application method storing module 19, it is known that the structural component to be inserted is the <TD>. Accordingly, the document structure checking module 20 checks whether the <TD> itself of document can be inserted into the <TD> of the template. As a result of the checking, it is determined that the insertion is impossible. Then, as a result of checking whether the content of <TD> of the document can be inserted into the <TD> of the template, it is determined that the insertion is possible. Therefore, the document structure checking module 20 determines that insertion of the structural component <TD> 414 into the content area “main” is valid from a structural viewpoint of the document. On the contrary, if it is attempted to insert the <TR> into a content area put in the <TD>, for example, then it is determined to be invalid from a structural viewpoint of the document at step 208, and a warning is displayed (step 210). Though it is assumed in the above description that the document structure checking module 20 refers to the information stored in the application method storing module 19 and the result of analysis by the template structure analyzing module 13 when checking the validity from a structural viewpoint of the document, it is possible to check validity from a structural viewpoint of the document without referring to the result of analysis by the template structure analyzing module 13 in the case where there is stored association between the template structure information and the document structure information in the application method storing module 19. As a result of applying the template to the document through the process described above, the document “index.html” is changed as shown in FIG. 13. That is, there is put a <tpl:put> tag, a special tag indicating that a structural component has been inserted in <TD> 1311, as shown in the document structure after application of the template. Description corresponding to the <TD> 1301 is provided in the <tpl:put> tag, though it is not shown. Then, specific description will be made on the operation of applying the template to another document shown in the flowchart in FIG. 3. Conceiving the application of the template to the document “index.html” described above as a master case (application of a template to one particular document for the purpose of specifying the method of the template application to be performed for other documents) here, description will be made on the case where similar application is performed for the other documents “page2.html” and “page3.html”. First, description will be made on application of the template to the document “page2.html” shown in FIG. 5. FIG. 14 shows the screen image to be displayed then. Though all the documents “index.html”, “page2.html” and “page3.html” are checked in FIG. 14, description will be made by focusing attention only on the document “page2.html” here. By checking the document “page2.html” to which the template is applied in the lower left area in FIG. 14, the “page2.html” is selected. Then, information identifying the document “page2.html” is sent to the structured document processor, and the document selection accepting module 16 accepts the information (step 301). The document structure analyzing module 17 then analyzes the structure of the document “page2.html” (step 302). Specifically, there is generated information about the document structure, which is shown on the right side of FIG. 5. The structural component retrieving module 22 then retrieves a structural component similar to that shown in the application method stored in the application method storing module 19, from among structural components included in the result of analysis by the document structure analyzing module 17 (step 303). It is shown in the application method storing module 19 that the second <TD> under the first <TR> under the first <TBODY> under the second <TABLE> under <BODY> has been inserted into the content area “main” as shown in FIG. 12. Accordingly, the structural component retrieving module 22 retrieves a structural component positioned similarly to this <TD>, from the document structure on the right side of FIG. 5, which is the result of analysis by the document structure analyzing module 17. In this case, it is recognized that the <TD> 514, which is the second <TD> under the first <TR>under the first <TBODY> under the second <TABLE> under <BODY>, also exists in the document structure on the right side of FIG. 5. There is no content area other than the “main” (YES at step 306), so that the template applying module 21 performs only insertion of the <TD> 514 into the content area “main” on a memory (step 307), and a preview image as shown in the lower right area in the FIG. 14 is then displayed. As a result of application of the template to the document through the process described above, the document structure of the document “page2.html” is similar to that shown in FIG. 1. However, description corresponding to the <TD> 514 in FIG. 5 is provided in the <tpl:put> tag. Next, description will be made on application of the template to the document “page3.html” shown in FIG. 6. FIG. 15 shows the screen image to be displayed then. Though all the documents “index.html”, “page2.html” and “page3.html” are checked in FIG. 15, description will be made by focusing attention only on the document “page3.html” here. By checking the document “page3.html” to which the template is applied in the lower left area in FIG. 15, the document “page3.html” is selected. Then, information identifying the document “page3.html” is sent to the structured document processor, and the document selection accepting module 16 accepts the information (step 301). The document structure analyzing module 17 then analyzes the structure of the document “page3.html” (step 302). Specifically, there is generated information about the document structure, which is shown on the right side of FIG. 6. The structural component retrieving module 22 then retrieves a structural component similar to that shown in the application method stored in the application method storing module 19, from among structural components included in the result of analysis by the document structure analyzing module 17 (step 303). It is shown in the application method storing module 19 that the second <TD> under the first <TR> under the first <TBODY> under the second <TABLE> under <BODY> has been inserted into the content area “main” as shown in FIG. 12. Accordingly, the structural component retrieving module 22 retrieves a structural component positioned similarly to this <TD> from the document structure on the right side of FIG. 6, which is the result of analysis by the document structure analyzing module 17. In this case, there is not found a structural component corresponding to the second <TD> under the first <TR> under the first <TBODY> under the second <TABLE> under <BODY> in the document structure on the right side of FIG. 6, and therefore, the structural component retrieving module 22 saves the contents of the information shown in FIG. 12, for example, and temporarily expands the insertion range (step 304). That is, the application method is rewritten with a method specifying that the first <TR> under the first <TBODY> under the second <TABLE> under <BODY> should be inserted into the content area “main”. The structural component retrieving module 22 then determines whether the expansion is valid from a structural viewpoint of the document (step 305). Specifically, by referring to the structure information, the result of analysis by the template structure analyzing module 13, the structural component retrieving module 22 recognizes that the content area “main” is put in the HTML tag <td>. Since the <TR> cannot be inserted into the <td>, the structural component retrieving module 22 determines that the expansion is not valid from a structural viewpoint of the document and re-expands the insertion range (step 304). That is, the template application method is rewritten with a method specifying that the first <TBODY> under the second <TABLE> under <BODY> should be inserted into the content area “main”. Next, the structural component retrieving module 22 determines whether the expansion is valid from a structural viewpoint of the document (step 305). The content area “main” is put in the HTML tag <td>, and it is impossible to insert the <TBODY> into the <td>. Therefore, the structural component retrieving module 22 determines that the expansion is not valid from a structural viewpoint of the document and re-expands the insertion range again (step 304). That is, the template application method is rewritten with a method specifying that the second <TABLE> under <BODY> should be inserted into the content area “main”. The structural component retrieving module 22 determines whether the expansion is valid from a structural viewpoint of the document (step 305). The content area “main” is put in the HTML tag <td>, and it is possible to insert the <TABLE> into the <td>. Therefore, the structural component retrieving module 22 determines that the expansion is valid from a structural viewpoint of the document, and retrieves a structural component positioned similar to the <TABLE> from the document structure on the right side of FIG. 6, which is the result of analysis by the document structure analyzing module 17. In this case, there also exists <TABLE> 612, which is the second <TABLE> under <BODY> in the document structure on the right side of FIG. 6. There is no content area other than the “main” (YES at step 306), so that the template applying module 21 performs only insertion of the <TABLE> 612 into the content area “main” on a memory (step 307), and a preview image as shown in the lower right area of the FIG. 15 is then displayed. As a result of application of the template to the document through the process described above, the document structure of the document “page3.html” is similar to that shown in FIG. 13. However, description corresponding to the <TABLE> 612 in FIG. 6 is provided in the <tpl:put> tag. A specific example of this embodiment has been described. Though it has not been mentioned in detail how the result of analysis by the template structure analyzing module 13 is retained in the above description, the template structure analyzing module 13 may analyze the template stored in the template storing module 11 to acquire template structure information each time the template structure information is required. Alternatively, the template structure information may be expanded on a memory when it is initially generated so that the structure information expanded on a memory can be used for subsequent processings. Similarly, the result of analysis by the document structure analyzing module 17 may be also acquired by analyzing the document stored in the document storing module 15 each time the analysis result is required. Alternatively, the document structure information may be expanded on a memory when it is initially generated so that the structure information expanded on a memory can be used for subsequent processings. Furthermore, though the validity check from a structural viewpoint of the document at step 305 is performed by the structural component retrieving module 22 in this embodiment, it is also possible that the information about the structural component after expansion is passed to the document structure checking module 20 and the document structure checking module 20 performs the validity check by referring to the result of analysis by the template structure analyzing module 13. In this embodiment, the template applying module 21 applies a template on a memory and a preview of the states of the document before/after the application of the template is provided so that the risk of losing document information due to the application of the template is minimized. However, application of a template by the template applying module 21 can be performed not on a memory but on a hard disk. By performing the process following the flowchart in FIG. 2, it is possible to specify a structural component (HTML tag) as a portion to be inserted into a content area when applying a template. Furthermore, by performing the process following the flowchart in FIG. 2, it is also possible to specify a different structural component (HTML tag) for each content area when the template is provided with multiple content areas. Furthermore, by performing the process following the flowchart in FIG. 3, it is possible to specify a portion to be inserted in a content area for a single document to automatically apply the template to multiple documents. The flowchart and block diagrams of FIGS. 1-3 illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is apparent to one skilled in the art that numerous modifications and departures from the specific embodiments described herein may be made without departing from the spirit and scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to a structured document processor for processing a structured document composed of one or multiple structural components, and in particular, to a structured document processor for applying a template to a structured document. There are a number of websites available on the Internet including commercial websites and private websites. Commercial websites typically have elaborate web pages for the purpose of attracting customers. In addition, the web pages may include a uniform design. For example, one format that may be used is a menu list located at the left side of the web pages and a bar with a logo of a company at the top of the web pages. If the logo of the company is changed, all the web pages included in the website have to be corrected. In the case of a big company, thousands or many thousands of web pages may have to be edited. This requires a great amount of work.
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<SOH> BRIEF SUMMARY OF THE INVENTION <EOH>According to one aspect of the present invention, a structured document processor comprises a structural component selection accepting module for accepting selection of a particular structural component among multiple structural components composing a predetermined document, and a template applying module for inserting the particular structural component, selection of which has been accepted by the structural component selection accepting module, into a predetermined content area included in a predetermined template. According to another aspect of the present invention, a method for processing a structured document comprises accepting selection of a particular structural component among multiple structural components composing a predetermined document stored in predetermined storing module, and inserting the particular structural component, selection of which has been accepted, into a predetermined content area included in a predetermined template stored in predetermined storing module. According to yet another aspect of the present invention, a computer program product for processing a structural document comprises a computer readable medium having computer readable program code embodied therein. The computer readable program code comprises computer readable program code configured to accept selection of a particular structural component among multiple structural components composing a predetermined document, and computer readable program code configured to insert the particular structural component, selection of which has been accepted, into a predetermined content area included in a predetermined template. Other aspects and features of the present invention, as defined solely by the claims, will become apparent to those ordinarily skilled in the art upon review of the following non-limited detailed description of the invention in conjunction with the accompanying figures.
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20040628
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20090113
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20050203
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63927.0
| 0
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PATEL, MANGLESH M
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STRUCTURED DOCUMENT PROCESSOR
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,880,203
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ACCEPTED
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Light positioning device
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A light positioning device. The light positioning device comprises a light guide plate, a light source assembly and a frame. The light guide plate comprises a protrusion and a recess. The light source assembly is disposed on the protrusion of the light guide plate and abuts the light guide plate. The light source assembly comprises a light source module received in the recess of the light guide plate. The frame is disposed under the light guide plate and light source assembly.
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1. A light positioning device, comprising: a light guide plate, with a protrusion and a recess; a light source assembly disposed on the protrusion of the light guide plate and abutting the light guide plate, the light source assembly comprising a light source module received in the recess of the light guide plate; and a frame disposed under the light guide plate and light source assembly. 2. The light positioning device as claimed in claim 1, wherein the light guide plate further comprises a main body, the protrusion and recess are formed on one side thereof and the light source assembly abuts the main body. 3. The light positioning device as claimed in claim 1, wherein the light source assembly further comprises a power transmission member electrically connected to the light source module. 4. The light positioning device as claimed in claim 3, wherein the power transmission member comprises a flexible printed circuit board (FPCB). 5. The light positioning device as claimed in claim 3, wherein the power transmission member comprises a printed circuit board (PCB). 6. The light positioning device as claimed in claim 1, wherein the light source module further comprises a light-emitting element. 7. The light positioning device as claimed in claim 6, wherein the light-emitting element comprises a light-emitting diode (LED). 8. The light positioning device as claimed in claim 6, wherein the light-emitting element comprises a cold cathode fluorescent lamp (CCFL). 9. The light positioning device as claimed in claim 1, wherein the recess is rectangular. 10. The light positioning device as claimed in claim 1, wherein the recess is curved. 11. The light positioning device as claimed in claim 1, wherein the recess is polygonal.
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BACKGROUND The present invention relates to a light positioning device, and in particular to a light positioning device capable of reducing errors in assembly of a light guide plate, a light source assembly and a frame thereof. LCD devices are generally multiple-layer structures comprising a light guide plate, a light source assembly, an LCD panel, a reflective plate, a diffusing plate and a frame. Conventionally, the light source assembly is first fixed on the frame and the light guide plate is then fitted into the frame. Referring to FIG. 1, one side 11 of a conventional frame 1 is formed with a plurality of protrusions 12 and a plurality of recesses 13. The protrusions 12 and recesses 13 are alternately formed on the side 11. Referring to FIG. 2, a conventional light source assembly 2 comprises a flexible circuit board 21 and a plurality of light source modules 22. Each light source module 22 comprises at least one light-emitting diode (LED). Referring to FIG. 3A, the light source assembly 2 is first disposed on the side 11 of the frame 1. At this point, the light source modules 22 of the light source assembly 2 are respectively received in the recesses 13 of the side 11. A light guide plate 3 is then fitted into the frame 1 and abuts the light source assembly 2 to form a light positioning device 10. Specifically, a tolerance or error may occur during manufacture of the frame 1. Further, assembly errors may occur between the light guide plate 3 and the frame 1 and between the light source assembly 2 and the frame 1. The cross section of the assembled light positioning device 10 is shown in FIG. 3B. Accordingly, a gap A exists between a light-input surface 31 of the light guide plate 3 and a light-output surface 23 of the light source modules and a displacement B exists between the central line of a LED 24 (or the light source module 22) of the light source assembly 2 and the central line of the light guide plate 3. The gap A and displacement B are often large, such that light from the LED 24 (or the light source module 22) cannot be effectively utilized by the light guide plate 3. Thus, the performance of the light positioning device 10 is adversely affected. Additionally, assembly of the light positioning device 10 is complicated, resulting in increased manufacturing time, manpower and cost. SUMMARY Accordingly, the invention provides an improved light positioning device to overcome the aforementioned problems. The light positioning device comprises a light guide plate, a light source assembly and a frame. The light guide plate comprises a protrusion and a recess. The light source assembly is disposed on the protrusion of the light guide plate and abuts the light guide plate. The light source assembly comprises a light source module received in the recess of the light guide plate. The frame is disposed under the light guide plate and light source assembly. The light guide plate further comprises a main body. The protrusion and recess are formed on one side of the main body and the light source assembly abuts the main body. The light source assembly further comprises a power transmission member electrically connected to the light source module. The power transmission member comprises a flexible printed circuit board (FPCB) or a printed circuit board (PCB). The light source module further comprises a light-emitting element. The light-emitting element comprises a light-emitting diode (LED) or a cold cathode fluorescent lamp (CCFL). The recess is rectangular, curved, or polygonal. A detailed description is given in the following embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: FIG. 1 is a schematic perspective view of a conventional frame; FIG. 2 is a schematic perspective view of a light source assembly; FIG. 3A is a schematic perspective view of a conventional light positioning device; FIG. 3B is a partial cross section according to FIG. 3A; FIG. 4 is a schematic top view of the light positioning device of an embodiment of the invention; FIG. 5A is a schematic top view of the light guide plate of the light positioning device of an embodiment of the invention; FIG. 5B is a schematic side view of the light guide plate of the light positioning device of an embodiment of the invention; FIG. 5C is another schematic side view of the light guide plate of the light positioning device of an embodiment of the invention; and FIG. 6 is a partial cross section according to FIG. 4. DETAILED DESCRIPTION Referring to FIG. 4, the light positioning device 100 comprises a light guide plate 110, a light source assembly 120 and a frame 130. Referring to FIG. 4 and FIG. 5A, the light guide plate 110 comprises a main body 111, a plurality of protrusions 112 and a plurality of recesses 113. The protrusions 112 and recesses 113 are alternately formed on one side of the main body 111. The light guide plate 110 can alternatively comprise lateral shapes as shown in FIG. 5B and FIG. 5C. As shown in FIGS. 4, 5A and 6, the light source assembly 120 is disposed on the protrusions 112 of the light guide plate 110 and abuts the main body 111 thereof. The light source assembly 120 comprises a plurality of light source modules 121 received in the recesses 113 of the light guide plate 110. Moreover, the light source assembly 120 comprises a power transmission member 122. The light source modules 121 are disposed on the power transmission member 122 and electrically connected thereto. The light source modules 121 can thus acquire power via the power transmission member 122. Additionally, the power transmission member 122 can be a flexible printed circuit board (FPCB) or a printed circuit board (PCB). As shown in FIG. 6, each light source module 121 further comprises a light-emitting element 123 disposed therein. The light-emitting element 123 can be a light-emitting diode (LED) or a cold cathode fluorescent lamp (CCFL). Specifically, although the recesses 113 of the light guide plate 110 of this embodiment are rectangular, the recesses 113 can selectively be curved or polygonal in accordance with the shape of the light source modules 121. The following description is directed to assembly of the light positioning device 100. The light source assembly 120 is directly fixed on the protrusions 112 of the light guide plate 110. At this point, a gap A′ between a light-input surface 114 of the main body 111 of the light guide plate 110 and a light-output surface 125 of each light source module 121 can be adjusted to be a minimal or optimal distance. The central lines of the light-emitting element 123 of each light source module 121 and main body 111 of the light guide plate 110 can also be adjusted to coincide with each other. As shown in FIG. 4, the assembled light source assembly 120 and light guide plate 110 are then fitted into the frame 130. At this point, the assembly of the light positioning device 100 is complete. In conclusion, the light positioning device 100 has many advantages including the following. Since the light source assembly 120 is fixed directly on the light guide plate 110, the assembly errors therebetween are reduced. Each light-emitting element 123 directly outputs light toward the center of the main body 111 of the light guide plate 110. Thus, light from each light-emitting element 123 is effectively utilized by the light guide plate 110, enhancing brightness of the light positioning device 100 (or an LCD device). Moreover, the assembly of the light positioning device 100 is simplified, thereby reducing manufacturing time, manpower and cost. Additionally, the frame 130 is simplified. Namely, the frame 130 is formed without any protrusions and recesses as are required by the conventional frame 1, thus reducing manufacturing time and cost. Further, since the frame 130 is simplified, the frame 130 provides more space for additional deployment than the conventional frame 1. While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
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<SOH> BACKGROUND <EOH>The present invention relates to a light positioning device, and in particular to a light positioning device capable of reducing errors in assembly of a light guide plate, a light source assembly and a frame thereof. LCD devices are generally multiple-layer structures comprising a light guide plate, a light source assembly, an LCD panel, a reflective plate, a diffusing plate and a frame. Conventionally, the light source assembly is first fixed on the frame and the light guide plate is then fitted into the frame. Referring to FIG. 1 , one side 11 of a conventional frame 1 is formed with a plurality of protrusions 12 and a plurality of recesses 13 . The protrusions 12 and recesses 13 are alternately formed on the side 11 . Referring to FIG. 2 , a conventional light source assembly 2 comprises a flexible circuit board 21 and a plurality of light source modules 22 . Each light source module 22 comprises at least one light-emitting diode (LED). Referring to FIG. 3A , the light source assembly 2 is first disposed on the side 11 of the frame 1 . At this point, the light source modules 22 of the light source assembly 2 are respectively received in the recesses 13 of the side 11 . A light guide plate 3 is then fitted into the frame 1 and abuts the light source assembly 2 to form a light positioning device 10 . Specifically, a tolerance or error may occur during manufacture of the frame 1 . Further, assembly errors may occur between the light guide plate 3 and the frame 1 and between the light source assembly 2 and the frame 1 . The cross section of the assembled light positioning device 10 is shown in FIG. 3B . Accordingly, a gap A exists between a light-input surface 31 of the light guide plate 3 and a light-output surface 23 of the light source modules and a displacement B exists between the central line of a LED 24 (or the light source module 22 ) of the light source assembly 2 and the central line of the light guide plate 3 . The gap A and displacement B are often large, such that light from the LED 24 (or the light source module 22 ) cannot be effectively utilized by the light guide plate 3 . Thus, the performance of the light positioning device 10 is adversely affected. Additionally, assembly of the light positioning device 10 is complicated, resulting in increased manufacturing time, manpower and cost.
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<SOH> SUMMARY <EOH>Accordingly, the invention provides an improved light positioning device to overcome the aforementioned problems. The light positioning device comprises a light guide plate, a light source assembly and a frame. The light guide plate comprises a protrusion and a recess. The light source assembly is disposed on the protrusion of the light guide plate and abuts the light guide plate. The light source assembly comprises a light source module received in the recess of the light guide plate. The frame is disposed under the light guide plate and light source assembly. The light guide plate further comprises a main body. The protrusion and recess are formed on one side of the main body and the light source assembly abuts the main body. The light source assembly further comprises a power transmission member electrically connected to the light source module. The power transmission member comprises a flexible printed circuit board (FPCB) or a printed circuit board (PCB). The light source module further comprises a light-emitting element. The light-emitting element comprises a light-emitting diode (LED) or a cold cathode fluorescent lamp (CCFL). The recess is rectangular, curved, or polygonal. A detailed description is given in the following embodiments with reference to the accompanying drawings.
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20040629
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20060905
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20051117
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72228.0
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LEE, GUNYOUNG T
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LIGHT POSITIONING DEVICE
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,880,216
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ACCEPTED
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Symmetric signal distribution through abutment connection
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The present invention provides a method and apparatus for managing a large number of associated interconnects within an integrated circuit involving a modular approach to the macro cell layout. In particular, internal signal paths are created within each macro cell that permit connections to other macros by abutting these macros adjacent to one another. Moreover, these internal signal paths permit efficient distribution of a common source signal to each of such connected macros. The layout of the internal macro cell signal paths of the present invention also permits each of these macros to be reflected about its Y-axis, thereby increasing its versatility in being utilized in various circuit designs.
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1. A method of routing internal signal paths contained on a macro cell, the macro cell having a top edge, a bottom edge, a left edge and a right edge, the internal routing occurring between a plurality of left terminals on the macro cell to a plurality of right terminals on the macro cell, the method comprising the steps of: placing n left terminals at terminal locations on the left edge of the macro cell, where said left terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the top edge, and wherein n is an integer; placing n right terminals at terminal locations on the right edge of the macro cell, where said right terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the top edge; and wherein said right terminals are adapted to contact left terminals of an additional macro cell whenever the left terminals of the additional macro cell are physically aligned with and connected to the right terminals of the macro cell; and, routing the internal signal paths between the left terminals of the macro cell and the right terminals of the macro cell so that an internal signal path is established between the left terminal location at location 1 and the right terminal location at location n, and for each integer k, 1<k≦n, an internal signal path is established between the left terminal of the macro cell at terminal location k and the right terminal at terminal location k−1. 2. The method of claim 1 further comprising the step of: supplying input signals to the macro cell to at least one of the left terminals of the macro cell. 3. The method of claim 1 further comprising the step of: supplying input signals to the macro cell to at least one of the right terminals of the macro cell. 4. A method of establishing signal paths between macro cells, each macro cell having a top edge, a bottom edge, a left edge and a right edge; the method comprising the steps of: placing n left terminals at terminal locations on the left edge of the first macro cell, where said left terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the top edge, and wherein n is an integer; placing n right terminals at terminal locations on the right edge of the first macro cell, where said right terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the top edge; and wherein said right terminals are adapted to contact left terminals of second macro cell whenever the left terminals of the second macro cell are physically aligned with and connected to the right terminals of the first macro cell; and, routing the internal signal paths between the left terminals of the first macro cell and the right terminals of the first macro cell so that an internal signal path is established between the left terminal at location 1 and the right terminal at location n; and for each integer k, 1<k≦n, an internal signal path is established between the left terminal at location k and the right terminal at location k−1. placing the second macro in contact with the first macro cell such that at least one of the left terminals on the second macro cell are physically aligned with and connected to at least one of the right terminals of the first macro cell. 5. The method of claim 4 wherein the right terminal locations on the right edge of the first macro cell correspond to the left terminal locations on the left edge of the second macro cell. 6. The method of claim 4 further comprising the step of: supplying input signals to the first macro cell at the left terminals of the first macro cell. 7. The method of claim 4 further comprising the step of: supplying input signals to the second macro cell at the right terminals of the second macro cell. 8. The method of claim 4 wherein the said first macro cell and said second macro cell are identical. 9. The method of claim 4 further comprising the step of: reducing occurrences of floating paths when said macro cells are connected. 10. A macro cell that reduces the need for external signal paths when the macro cell is connected by abutment to additional macro cells, each of said macro cells having a top edge, a bottom edge, a left edge and a right edge; the macro cell comprising: a plurality of n left terminals placed at terminal locations on the left edge of the macro cell, where said left terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the top edge, and wherein n is an integer; a plurality of n right terminals placed at terminal locations on the right edge of the macro cell, where said right terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the top edge; and wherein said right terminals are adapted to contact left terminals of an additional macro cell whenever the left terminals of the additional macro cell are physically aligned with and connected to the right terminals of the macro cell; and, a plurality of internal signal paths between the plurality of left terminals of the macro cell and the plurality of right terminals of the macro cell so that an internal signal path is established between the left terminal location at location 1 and the right terminal location at location n, and for each integer k, 1<k≦n, an internal signal path is established between the left terminal of the macro cell at terminal location k and the right terminal at terminal location k−1. 11. The macro cell of claim 10 wherein the left terminals on the macro cell are configured to receive input signals to the macro cell. 12. The macro cell of claim 10 wherein the right terminals on the macro cell are configured to receive input signals to the macro cell. 13. A method of routing internal signal paths contained on a macro cell, the macro cell having a surface in the shape of a polygon having first, second, third and fourth edges, wherein said first edge is opposed to said third edge and said second edge is opposed to said fourth edge; said internal routing occurring between a plurality of terminals located on the first edge and a plurality of terminals located on the third edge, the method comprising the steps of: placing n terminals at terminal locations on the first edge of the macro cell, where said first edge terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the second edge, and wherein n is an integer; placing n terminals at terminal locations on the third edge of the macro cell, where said third edge terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the second edge; and wherein said edge terminals on the third edge are adapted to contact terminals of an additional macro cell whenever the terminals of the additional macro cell are physically aligned with and connected to the edge terminals on the third edge of the macro cell; and, routing the internal signal paths between the edge terminals on the first edge of the macro cell and the edge terminals on the third edge of the macro cell so that an internal signal path is established between the edge terminal location at location 1 on the first edge and the edge terminal location at location n on the third edge, and for each integer k, 1<k≦n, an internal signal path is established between the edge terminal of the macro cell at terminal location k on the first edge and the edge terminal at terminal location k−1 on the third edge. 14. The method of claim 13 further comprising the step of: supplying input signals to the macro cell to at least one of the terminal locations on the first edge of the macro cell. 15. The method of claim 13 further comprising the step of: supplying input signals to the macro cell to at least one of the terminal locations on the third edge of the macro cell. 16. A method of establishing signal paths between macro cells, each said macro cell having a surface in the shape of a polygon having first, second, third and fourth edges, wherein said first edge is opposed to said third edge and said second edge is opposed to said fourth edge; said method comprising: placing n terminals at terminal locations on the first edge of the first macro cell, where said first edge terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the second edge, and wherein n is an integer; placing n terminals at terminal locations on the third edge of the first macro cell, where said third edge terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the second edge; and wherein said edge terminals on the third edge are adapted to contact edge terminals on the first edge of the second macro cell whenever the edge terminals on the first edge of the second macro cell are physically aligned with and connected to the edge terminals on the third edge of the first macro cell; and, routing the internal signal paths between the edge terminals on the first edge of the first macro cell and the edge terminals on the third edge of the first macro cell so that an internal signal path is established between the edge terminal at location 1 on the first edge and the edge terminal at location n on the third edge; and for each integer k, 1<k≦n, an internal signal path is established between the edge terminal at location k on the first edge and the edge terminal at location k−1 on the third edge; placing the second macro in contact with the first macro cell such that at least one of the edge terminals on the first edge of the second macro cell are physically aligned with and connected to at least one of the edge terminals on the third edge of the first macro cell. 17. The method of claim 16 wherein the terminal locations on the third edge of the first macro cell establish a connection with the terminal locations on the first edge of the second macro cell. 18. The method of claim 16 further comprising the step of: supplying input signals to the first macro cell to at least one of the terminal locations on the first edge of the first macro cell. 19. The method of claim 16 further comprising the step of: supplying input signals to the second macro cell to at least one of the terminal locations on the third edge of the second macro cell. 20. The method of claim 16 wherein the said first macro cell and said second macro cell are identical. 21. The method of claim 16 further comprising the step of: reducing occurrences of floating paths when said macro cells are connected. 22. A macro cell that reduces the need for external signal paths when the macro cell is connected by abutment to additional macro cells, said macro cell having a surface in the shape of a polygon having first, second, third and fourth edges, wherein said first edge is opposed to said third edge and said second edge is opposed to said fourth edge; the macro cell comprising: a plurality of n terminals placed at terminal locations on the first edge of the macro cell, where said first edge terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the second edge, and wherein n is an integer; a plurality of n terminals placed at terminal locations on the third edge of the macro cell, where said third edge terminal locations are sequentially numbered 1 through n, with 1 being the location nearest the second edge; and wherein said edge terminals on the third edge are adapted to contact terminals of an additional macro cell whenever the terminals of the additional macro cell are physically aligned with and connected to the edge terminals on the third edge of the macro cell; and, a plurality of internal signal paths between the plurality of edge terminals on the first edge of the macro cell and the plurality of edge terminals of the third edge of the macro cell so that an internal signal path is established between the edge terminal location at location 1 on the first edge and the edge terminal location at location n on the third edge, and for each integer k, 1<k≦n, an internal signal path is established between the edge terminal of the macro cell at terminal location k on the first edge and the edge terminal at terminal location k−1 on the third edge. 23. The macro cell of claim 22 wherein the first edge terminals on the macro cell are configured to receive input signals to the macro cell. 24. The macro cell of claim 22 wherein the third edge terminals on the macro cell are configured to receive input signals to the macro cell.
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FIELD OF THE INVENTION The present invention generally relates to semiconductors and more specifically to signal routing between macros by abutment placement of these macros. BACKGROUND OF THE INVENTION The layout for large-scale integrated microchips is one of the most time consuming tasks in the design cycle for an integrated circuit (IC). One input to this design process is a partitioned circuit wherein elementary components of the circuit are grouped to build a number of macro cells. On the borders of these cells, signal trace endpoints or terminals are located to provide signal paths between circuit blocks of the IC and connection layers such as metal or polysilicon layers. These connection layers, also known as interconnects, require some finite width and thickness to ensure reliability of the interconnect and signal integrity. The output of this design process is a layout for the integrated circuit. The layout describes the placement of the macro cells and the routes for the interconnects between the macro cells. One common objective in layout optimization is to find an arrangement that minimizes overall area. Cells are not allowed to overlap each other, and the routing has to meet specific technical constraints, i.e., space between parallel wires has to be added to prevent short circuits and transmission effects, and for some critical traces, the delay has to stay below a given threshold, which results in maximal admissible wire lengths for these traces. One frequently occurring situation encountered in this design process is when a single source is used to generate identical or duplicate signals, e.g., clocks, currents, etc. that are to be supplied to multiple destinations. An example would be a biasing current that is being supplied to analog circuits. The distribution of these currents can be a significant challenge in situations where the analog circuits are macro-based and multiple distributions are to occur. This becomes even more difficult when the multiple analog circuits require independent biasing currents from the source. That is, while the source can readily produce independent biasing current for any number of analog macros, providing each current to each analog macro is problematic due to the fact that biasing currents are delicate and sensitive signals. Frequently in the prior art custom routing is employed. This not only increases costs of design but invariable results in increased numbers of signal paths between blocks. When numerous signal paths are required between circuit blocks, the routing congestion caused by placement of the associated interconnects will increase the overall size of the IC and thus increase the cost of the product. That congestion has an increased effect when the area between the circuit blocks is limited. A further problem arises when numerous tightly spaced functional blocks require a high number of signal paths between these blocks. The associated numerous interconnects will cause even more IC area congestion that will further increase the IC size and associated cost. SUMMARY OF THE INVENTION The present invention overcomes the disadvantages and limitations of the prior art by providing a method and apparatus to reduce or eliminate the need to connect individual macro cell signals with traces that are supplemental to the macro cell layout. In particular, in circumstances where a macro can be employed for multiple instantiations, and where such design signals must be distributed to each instantiation, certain commonalities may exist which can be exploited to effect the routings. That is, a custom route is, in effect, created inside the macros and the connection between macros and the source signal is achieved by abutting these macros adjacent to one another so that the signal connections are made to adjacent macros. Thus, in the example where the source signal is a biasing current, each of the analog macros can be supplied their own independent biasing current with minimal, if any, routing paths external to the analog macros. Further, these analog macros are capable of being reflected (i.e., symmetric) in their Y-axis while maintaining the one-to-one connection by abutment in the layout. This capability provides greater flexibility in the use of various designs. BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments of the present invention will now be described in detail in conjunction with the annexed drawings, in which: FIG. 1 is a schematic diagram of a typical macro cell layout where routing of source signals comprises abutting successive macro cells; FIG. 2 is a schematic diagram of a macro cell layout in which the macro cells are abutted which further depicts the custom routing performed inside of the macros; FIGS. 3A and 3B are schematic diagrams of an embodiment of the invention in which the internal routing performed inside of the macros comprises an additional diagonal routing which permits the macro to be reflected about its Y-axis, FIG. 3B being the post-reflection of FIG. 3A; FIG. 4 is a schematic diagram of the additional diagonal routing of the present invention being applied to layout of FIG. 2; and, FIG. 5 is a schematic diagram of an additional embodiment of the invention which illustrates use of the post-reflected macros of FIG. 3B employed in a macro cell layout containing abutted macro cells. DETAILED DESCRIPTION The present invention provides a method and apparatus for managing a large number of associated interconnects within an integrated circuit involving a modular approach to the macro cell layout. The invention is particularly applicable in situations in which a single source is used to generate identical or duplicate signals that are to be supplied to multiple destinations. The following embodiments of the invention will be described with reference to biasing currents (IBIAS) being supplied to multiple analog circuits. The invention is not so limited however, as it is applicable to any distribution of one or more signals to multiple destinations (to include digital signals and/or non-analog macros). In the following discussions, the exemplary macro cell is a rectangle and in the accompanying figures, the terms “left”, “right”, “L”, “R”, “top” and “bottom” are introduced to describe the relationship between one side of the macro cell and its opposing side. These terms are not meant to imply any one particular orientation or shape of the macro cell. It should be understood from the present context that these terms are exemplary and non-limiting. Furthermore, the concepts of the present invention are more broadly applicable to macro cells of other shapes. Generally, macro cells are square or rectangular, as such shapes are most practical, but the invention can be applied to macro cells of any symmetric, four-sided polygonal shape. In fact, in theory, the invention could be applied to non-symmetric polygons and/or polygons of any number of sides, although such shapes are not likely to be practical in most cases. Generally, the invention is most effectively used when a plurality of macro cells have similar shape and are laid out so that they have parallel adjacent sides. However, while not perhaps as practical, in theory, the macro cells need not necessarily all have the same shape and the plurality of macro cells need not be laid out so that every side of every macro is adjacent and/or parallel to a side of another macro cell. FIG. 1 illustrates an example of a source macro 102 generating identical bias currents at four separate output terminals (IBIAS[0-3]). These bias currents are distributed to four analog macros (104, 106, 108 and 110), where these macros are abutted together in the manner shown. In such a circuit, only one IBIAS signal can be used per analog macro. Assuming Analog Macro 104 receives its IBIAS signal at its input terminal IBIAS[0] 140, this signal is tapped off and thereby terminates within the Analog Macro 104 and does not propagate along the indicated path 130. Consequently, Analog Macro 106 must receive its IBIAS signal via a terminal location different than its IBIAS [0] input terminal 160. Accordingly, since the input terminal receiving the IBIAS signal thus varies, four different analog macros designs are required. While it would be possible to use four identical macros, this would require some additional routing external to the macros and accordingly is subject to many of the problems in the prior art that the practice of abutting macros is attempting to overcome. FIG. 2 illustrates four identical analog macros (204, 206, 208 and 210) which are being supplied a bias signal from Source Macro 102. FIG. 2 further illustrates custom routing done inside each of these macros as a logic shifter. As illustrated, this shifting occurs to place a “live” or untapped signal at the top of the macro's right edge for connecting to a subsequent macro. Each analog macro contains an input terminal or port (IBIAS[0]) that connects to one of the IBIAS output terminals (IBIAS[0-3], items 120, 121, 122 and 123) of the Source Macro 102. That is, path 214 supplies the IBIAS current at output terminal IBIAS[1], item 121, of Source Macro 102 to the IBIAS[0] input terminal, item 260 of Analog Macro 206. Similarly, paths 216 and 218 supply an IBIAS signal to input terminals 280 and 290 of Analog Macros 208 and 210, respectively. Input terminal, item 240 of Analog Macro 204, receives an IBIAS signal directly from its abutment to output terminal IBIAS[0], item 120, of the source macro. FIG. 2 illustrates an example in which four analog macros and four output IBIAS terminals are being employed. The number of IBIAS output terminals can be as large as needed to supply a larger number of analog macros, as long as the shifter routing inside each of the analog macros is done accordingly to match the source macro. It should also be noted that not all of the IBIAS outputs from the source macro need to be connected to an analog macro—e.g., in FIG. 2, less than four analog macros could be abutted using the internal routing of the analog macro depicted. FIGS. 3A and 3B illustrate an embodiment of the invention in which the internal routing performed inside of the analog macros comprises an additional diagonal routing path 304. Thus as depicted in FIG. 3A, the IBIAS[0] terminal positioned on the left edge L of Analog Macro 302, item 320, is electrically connected to another IBIAS[0] terminal, item 330, positioned on the right edge R. This creation of a duplicate terminal or port of IBIAS[0] on the opposed edge of the macro realizes several advantages. One such example is that it permits the macro to be reflected about its Y-axis. FIG. 3B depicts the post reflection of the analog macro of FIG. 3A. This reflection capability provides additional flexibility in the use of an analog macro (such as Analog Macro 302) in circuit design. Accordingly, such an analog macro will have increased utility in that it can be employed in a greater number of designs. The above described internal routing of Analog Macro 302 in FIG. 3A can be described more generally with the introduction of some additional terms, and without any references to “left” and “right” edges. Analog Macro 302 can be described as having first, second, third and fourth edges, items 341-344 respectively. The first edge 341 is opposed to the third edge 343 and the second edge 342 is opposed to the fourth edge 344. Terminals are located along both the first and third edges. These terminals are sequentially numbered 1 through n (n being 4 in FIG. 3A) with 1 being the location nearest the second edge 342. The routing path 304 can then be described as being between the edge terminal (item 320) at location 1 on the first edge and the edge terminal (item 330) at location n on the third edge. Each of the remaining paths can then be described as being between the edge terminal at location k on the first edge 341 and the edge terminal at location k−1 on the third edge 343. It should be noted that Analog Macro 302 of FIG. 3B is also accurately described by this convention with the first, second, third and fourth edges being items 351-354, respectively. An additional advantage of this embodiment of the invention is illustrated in FIG. 4 in which each of the analog macros of FIG. 2 (204, 206, 208 and 210) have been replaced by Analog Macro 302 (and identified in the figure as 404, 406, 408 and 410 respectively). As noted above in the discussion of FIG. 2, paths 214, 216 and 218 supply an IBIAS signal from Source Macro 102 to Analog Macros 406, 408 and 410, respectively. One important distinction between the circuits depicted in FIGS. 2 and 4 is that previously there existed several floating paths, paths that are essentially unconnected, lacking both a source and a destination. The presence of floating paths creates problems in some delicate circuits as such paths are susceptible to noise. FIG. 4 illustrates how each of the previous floating paths of FIG. 2 (220, 222 and 224) are now electrically connected to an IBIAS[0] terminal of an analog macro. Thus, path 220 is now connected at terminal 463, via path 412 to the IBIAS[0] terminal, item 440, of Analog Macro 404. Similarly, previous floating paths 222 and 224 are also now connected by the analog macro's internal routing according to this embodiment of the invention (path 414 connecting 222 to terminal 460 of Analog Macro 406 and path 416 connecting 224 to terminal 480 of Analog Macro 408). FIG. 5 is a schematic diagram of an additional embodiment of the invention which illustrates use of the reflected macro of FIG. 3B. As in FIG. 2, four analog macros (504, 506, 508 and 510) are supplied a biasing current from the Source Macro 102. As illustrated, each right edge (R) of the analog macros appears on the left side of the macro. The shifter is still maintained in each macro. However, the start connection from the Source Macro 102 has changed compared to the layout of FIG. 2. That is, the source macro output connection IBIAS[3], item 123, connects via a direct abutment with the IBIAS[0] terminal, item 543 appearing on the “R” edge of Analog Macro 504 and via diagonal path 518, to a duplicate IBIAS[0] terminal, item 550, appearing on the “L” edge of the analog macro. The source macro output connection IBIAS[2], item 122, connects via path 516 to the “R” IBIAS[0] terminal, item 563 of Analog Macro 506 and via path 520, to its “L” IBIAS[0] terminal, item 570 as well. Similarly, IBIAS[0] terminals of Analog Macros 508 and 510 (items 583 and 593, respectively) are connected to the appropriate IBIAS from the Source Macro 102. Relative to FIG. 2, the order of the connections has been changed using the reflected macro, yet the function of providing a source signal to each IBIAS[0] input terminal of the analog macros has been maintained. Moreover, this function has been achieved without the need of any external paths. Further, the floating connections (220, 222 and 224) present in FIG. 2 have been eliminated. While the invention has been described with reference to the preferred embodiment thereof, it will be appreciated by those of ordinary skill in the art that modifications can be made to the structure and elements of the invention without departing from the spirit and scope of the invention as a whole.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The layout for large-scale integrated microchips is one of the most time consuming tasks in the design cycle for an integrated circuit (IC). One input to this design process is a partitioned circuit wherein elementary components of the circuit are grouped to build a number of macro cells. On the borders of these cells, signal trace endpoints or terminals are located to provide signal paths between circuit blocks of the IC and connection layers such as metal or polysilicon layers. These connection layers, also known as interconnects, require some finite width and thickness to ensure reliability of the interconnect and signal integrity. The output of this design process is a layout for the integrated circuit. The layout describes the placement of the macro cells and the routes for the interconnects between the macro cells. One common objective in layout optimization is to find an arrangement that minimizes overall area. Cells are not allowed to overlap each other, and the routing has to meet specific technical constraints, i.e., space between parallel wires has to be added to prevent short circuits and transmission effects, and for some critical traces, the delay has to stay below a given threshold, which results in maximal admissible wire lengths for these traces. One frequently occurring situation encountered in this design process is when a single source is used to generate identical or duplicate signals, e.g., clocks, currents, etc. that are to be supplied to multiple destinations. An example would be a biasing current that is being supplied to analog circuits. The distribution of these currents can be a significant challenge in situations where the analog circuits are macro-based and multiple distributions are to occur. This becomes even more difficult when the multiple analog circuits require independent biasing currents from the source. That is, while the source can readily produce independent biasing current for any number of analog macros, providing each current to each analog macro is problematic due to the fact that biasing currents are delicate and sensitive signals. Frequently in the prior art custom routing is employed. This not only increases costs of design but invariable results in increased numbers of signal paths between blocks. When numerous signal paths are required between circuit blocks, the routing congestion caused by placement of the associated interconnects will increase the overall size of the IC and thus increase the cost of the product. That congestion has an increased effect when the area between the circuit blocks is limited. A further problem arises when numerous tightly spaced functional blocks require a high number of signal paths between these blocks. The associated numerous interconnects will cause even more IC area congestion that will further increase the IC size and associated cost.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention overcomes the disadvantages and limitations of the prior art by providing a method and apparatus to reduce or eliminate the need to connect individual macro cell signals with traces that are supplemental to the macro cell layout. In particular, in circumstances where a macro can be employed for multiple instantiations, and where such design signals must be distributed to each instantiation, certain commonalities may exist which can be exploited to effect the routings. That is, a custom route is, in effect, created inside the macros and the connection between macros and the source signal is achieved by abutting these macros adjacent to one another so that the signal connections are made to adjacent macros. Thus, in the example where the source signal is a biasing current, each of the analog macros can be supplied their own independent biasing current with minimal, if any, routing paths external to the analog macros. Further, these analog macros are capable of being reflected (i.e., symmetric) in their Y-axis while maintaining the one-to-one connection by abutment in the layout. This capability provides greater flexibility in the use of various designs.
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20040629
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20080318
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20051229
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63723.0
| 0
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GARBOWSKI, LEIGH M
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SYMMETRIC SIGNAL DISTRIBUTION THROUGH ABUTMENT CONNECTION
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,880,324
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ACCEPTED
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Waterproof structure of building waterproof structure
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A waterproof structure of a building, includes: at least two face members disposed on an exterior of the building; a sealing member disposed between end edge portions of the face members; a joint covering member disposed between the end edge portions. The end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween. The sealing member is disposed between the end edge portions to close the gap between the end edge portions. The joint covering member covers and presses the sealing member from an exterior side. The joint covering member is attached to the constrained portions acting elastic force between the constrained portions.
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1. A waterproof structure of a building, comprising: at least two face members each having an end edge portion, the at least two face members disposed on an exterior of the building so that the end edge portions are opposed to each other; a sealing member disposed between the end edge portions; and a joint covering member that is elastically deformable and disposed between the end edge portions; wherein the end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween; the sealing member is disposed between the end edge portions to close the gap between the end edge portions; the joint covering member covers and presses the sealing member from an exterior side; and the joint covering member is attached to the constrained portions acting elastic force between the constrained portions. 2. The waterproof structure according to claim 1, further comprising: an anchor clip extending along the end edge portions; wherein the anchor clip is inserted into the gap being engaged with the end edge portions to be pressed and fitted on a backing member that is disposed on a back side of the face member. 3. The waterproof structure according to claim 1, further comprising: an attaching clip for attaching an attached object to be disposed on the face member; wherein the attaching clip is attached to pinch the joint cover member from an outer side thereof. 4. The waterproof structure according to claim 1, further comprising: a cover member having a plate portion and a fitting portion integrated to a lower face of the plate portion; wherein the fitting portion is attached to the constrained portions. 5. The waterproof structure according to claim 4, wherein at least a part of the constrained portions are disposed at an eave side of the building; and the cover member covers an eave of the building. 6. The waterproof structure according to claim 4, wherein at least a part of the constrained portions are disposed on a water upstream side of the building; and the cover member covers the water upstream side of the building. 7. The waterproof structure according to claim 4, wherein the fitting portion includes a cross section having a substantially U-like shape with a narrowed opening. 8. The waterproof structure according to claim 1, further comprising: an adhesive material attached on the sealing member, for adhering to the end edge portions. 9. A building, comprising: a roof; a supporting member that supports the roof; at least two face members each having an end edge portion, the at least two face members disposed on an exterior of the building so that the end edge portions are opposed to each other; a sealing member disposed between the end edge portions; and a joint covering member that is elastically deformable and disposed between the end edge portions; wherein the end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween; the sealing member is disposed between the end edge portions to close the gap between the end edge portions; the joint covering member covers and presses the sealing member from an exterior side; and the joint covering member is attached to the constrained portions acting elastic force between the constrained portions.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof structure of a building using a cover member. 2. Background Art Generally, an outside joint portion of a building of a roof, a balcony floor, an outer wall, a surrounding of an opening or the like is provided with a sealing member to constitute a waterproof structure. A sealing member described in Japanese Patent No. 2519660 is arranged at inside of a joiner for connecting to engage roof sheets and constituted by forming a sealing member main body in an inverse U-like shape by an elastic material and forming a single or a plurality of fin-like sealing valves at positions on an inner side of the sealing member main body opposed thereto. According to the above-described sealing member, the sealing valve squeezes the roof sheet members to eliminate a clearance therebetween to thereby prevent invasion of water. Further, according to a folded sheet roof described in JP-A-7-34609, there is provided a waterproof structure of the folded sheet roof attaching a drip or the like to an attaching member installed above bulged shape head portions of contiguous ridge portions and an attaching apparatus constituted by integrally connecting a locking member fit to attach to constrained portions between valley portions interposed by the contiguous ridge portions and the attaching member. According to the above-described waterproof structure of the folded sheet roof, the attaching apparatus is formed integrally therewith and therefore, fabrication cost can be reduced, there is not a concern of breaking joint between constituent members of the attaching apparatus even when a strong wind of typhoon or the like is brought about and the drip or the like can solidly be fixed to the folded sheet roof. SUMMARY OF THE INVENTION However, according to the sealing member described in Japanese Patent No. 2519660, there poses a problem that when the fin-like sealing valve is subjected to ageing deterioration, the sealing valve is opened by a reduction in an elastic force and water is liable to leak. Further, according to the waterproof structure of the folded sheet roof described in JP-A-7-34609, when an interval between the bulged shape head portions of the contiguous ridge portions is widened, a volume of the attaching apparatus is increased to increase cost. Hence, it is an object of the invention to provide a cover member and a waterproof structure of a building using a cover member which resolve the above-described problem, in which water is difficult to leak and which is highly reliable at low cost. The invention provides a waterproof structure of a building, including: at least two face members each having an end edge portion, the at least two face members disposed on an exterior of the building so that the end edge portions are opposed to each other; a sealing member disposed between the end edge portions; and a joint covering member that is elastically deformable and disposed between the end edge portions; wherein the end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween; the sealing member is disposed between the end edge portions to close the gap between the end edge portions; the joint covering member covers and presses the sealing member from an exterior side; and the joint covering member is attached to the constrained portions acting elastic force between the constrained portions. Preferably, the waterproof structure further includes an anchor clip extending along the end edge portions; wherein the anchor clip is inserted into the gap being engaged with the end edge portions to be pressed and fitted on a backing member that is disposed on a back side of the face member. Preferably, the waterproof structure further includes an attaching clip for attaching an attached object to be disposed on the face member; wherein the attaching clip is attached to pinch the joint cover member from an outer side thereof. Preferably, the waterproof structure includes: a cover member having a plate portion and a fitting portion integrated to a lower face of the plate portion; wherein the fitting portion is attached to the constrained portions. Preferably, at least a part of the constrained portions are disposed at an eave side of the building; and the cover member covers an eave of the building. Preferably, at least a part of the constrained portions are disposed on a water upstream side of the building; and the cover member covers the water upstream side of the building. Preferably, the waterproof structure includes: an adhesive material attached on the sealing member, for adhering to the end edge portions. Preferably, the fitting portion includes a cross section having a substantially U-like shape with a narrowed opening. The invention may provide a building, including: a roof; a supporting member that supports the roof; at least two face members each having an end edge portion, the at least two face members disposed on an exterior of the building so that the end edge portions are opposed to each other; a sealing member disposed between the end edge portions; and a joint covering member that is elastically deformable and disposed between the end edge portions; wherein the end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween; the sealing member is disposed between the end edge portions to close the gap between the end edge portions; the joint covering member covers and presses the sealing member from an exterior side; and the joint covering member is attached to the constrained portions acting elastic force between the constrained portions. According to one aspect of the invention, the sealing member is attached to close the gap between the end edge portions of the face members, and the joint cover member is formed by the elastic deformable member to press the sealing member to cover from the outer side and fit to attach to between the constrained portions by operating the elastic force. As a result, the sealing member is brought into close contact with the end edge portions of the press members and therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, waterproof construction operation is facilitated. At this occasion, there is not opening or the like of a fin-like sealing member by an ageing deterioration, which is excellent in durability. According to another aspect of the invention, further, the anchor clip is inserted to between the end edge portions of the face members along the longitudinal direction of the end edge portion, the anchor clip is made to be able to be pressed to attach to the backing member at the back face of the face member by being locked by the two end edge portions of the face members and therefore, when the anchor clip is fixedly attached to the backing member by using the screw or the like after tackedly laying the face members. the face members can actually be fixed to the backing member. At this occasion, the screw for fixedly attaching the anchor clip is covered by the joint cover and the sealing member and therefore, water is not leaked from the screw hole. According to another aspect of the invention, further, the attaching clip is attached to pinch the joint cover member from an outer side, the attached object provided above the face member is attached by the attaching metal piece and therefore, the attached object can easily be attached while ensuring the waterproof structure. According to another aspect of the invention, the cover member includes the plate portion and the fitting portion integrated to the low face, having the section substantially in the inverse U-like shape and having the shape narrowing the opening side, and the fitting portion is made to be fit to attach to the constrained portion. As a result, the cover member is fit to attach to the constrained portion and therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, waterproof construction operation is facilitated. At this occasion, there is not an opening or the like brought about in the fin-like sealing member by an ageing deterioration as in the prior art, which is excellent in durability. According to another aspect of the invention, further, the cover member is the eaves side cover member and therefore, the cover member may only be fit to attach to between the member on the eaves side and the member including the projected portion having the constrained portion provided at the joint portion of the face members and waterproof construction operation is facilitated. Further, a nail head is not exposed, which is excellent in design performance. According to another aspect of the invention, the cover member is on the water upstream side and therefore, the cover member may only be fit to attach to between the member on the water upstream side and the member including the projected portion having the constrained portion provided at the joint portion of the face members and waterproof construction operation is facilitated. BRIEF DESCRIPTION OF THE DRAWINGS The present invention may be more readily described with reference to the accompanying drawings: FIGS. 1A and 1B show Embodiment 1 of the invention, in which FIG. 1A is a perspective view showing a waterproof structure of a roof and FIG. 1B is a sectional view taken along a line Ib-Ib of FIG. 1A. FIG. 2A is a perspective view of a roof face member and FIG. 2B is a sectional view thereof. FIG. 3 is a perspective view of a joint cover member. FIG. 4 is a perspective view of a sealing member. FIG. 5 is a perspective view of an anchor clip. FIG. 6 is a disassembled perspective view of an attaching metal piece. FIG. 7 is a sectional view of a waterproof structure of a roof according to Modified Example 1 of Embodiment 1. FIG. 8 is a sectional view of a waterproof structure of a roof according to Modified Example 2 of Embodiment 1. FIG. 9 is a sectional view of a waterproof structure of a roof according to Modified Example 3 of Embodiment 1. FIGS. 10A and 10B show Embodiment 2 of the invention, in which FIG. 10A is a sectional view of a roof before attaching a sealing member and FIG. 10B is a sectional view showing a waterproof structure of the roof. FIG. 11 is an explanatory view of attaching an eaves side cover provided between a roof and a cover above a gutter. FIG. 12A is a sectional view of an eaves side of a roof, FIG. 12B is a sectional view enlarging a portion b, FIG. 12C is a sectional view enlarging a portion c, and FIG. 12D is a sectional view enlarging a portion d. FIGS. 13A and 13B are explanatory views of attaching a cover on an up stream side of water provided between a proof portion on an upstream side of water and a joint cover. FIG. 14A is a sectional view of a roof on an upstream side of water, and FIG. 14B is a sectional view enlarging a portion b. FIG. 15 is an elevational disassembled view showing a cross section of a waterproof structure according another embodiment. FIG. 16 is an elevational view showing a cross section the waterproof structure shown in FIG. 15 in a state that the structure is assembled. FIG. 17 is a perspective view of a building according to an embodiment of the invention. FIG. 18 is a perspective view of a building according to another embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed explanation will be given of embodiments of the invention in reference to the drawings as follows. (Embodiment 1) FIG. 1 through FIG. 6 show Embodiment 1 of the invention, FIG. 1A is a perspective view showing a waterproof structure of a roof, FIG. 1B is a sectional view taken along a line Ib-Ib of FIG. 1A. FIG. 2A is a perspective view of a roof face member and FIG. 2A is a sectional view thereof. FIG. 3 is a perspective view of a joint cover member. FIG. 4 is a perspective view of a sealing member. FIG. 5 is a perspective view of an anchor clip. FIG. 6 is a disassembled perspective view of an attaching metal piece. Embodiment 1 is a waterproof structure of a building constituted by contiguously attaching roof face members 1, 1, 1, . . . on an exterior side of an upper face of the building and providing a sealing member 3 and a joint cover member 4 between end edge members of the roof face members 1 opposed to each other. As shown by FIG. 1B, both of the end edge members of the roof face members 1, 1 contiguous to each other are folded to bend to project to the exterior side, roots of the two projected end edge portions are bulged from front end sides thereof and the roots of the two end edge portions are formed with constricted portions 5 for narrowing an interval between the end edge portions. Explaining in further details in reference to FIG. 2, the roof face member 1 is formed by a metal sheet (sheet thickness: 0.3 through 0.6 mm) of a stainless steel sheet or a vinyl chloride resin coated steel sheet or the like and is formed by a flat roof main body 11, folded to bend portions 12 constituted by folding to bend both side end edge portions of the roof main body 11 in right angle, fold to bend portions 13 constituted by folding to bend front ends of the folded to bend portions 12, and fold to bend portions 14 constituted by further folding to bend front ends of the fold to bend portions 13 substantially upwardly. According to the above-described roof face member 1, a width between the end edge portions is made to be 300 through, 450 mm and a height dimension from the fold to bend portion 12 to an upper end of the fold to bend portion 14 is made to be 20 through 30 mm. As shown by FIG. 1B, the sealing member 3 is attached to close an interval between the end edge portions of the roof face members 1, 1. The sealing member 3 is formed by EPDM (ethylene-propylene terpolymer) foamed material, butyl species rubber, denatured silicone or the like. As shown by FIG. 4, the sealing member 3 comprises a main body 31 having a long D-like shape, and a pair of leg portions 32, 32 hung from both sides of a bottom portion of the main body 31 and the leg portions 32, 32 are fit to attach to outer sides. of the fold to bend portions 14 of the roof face member 1. The joint cover member 4 is formed by a metal sheet (sheet thickness: 0.3 through 0.6 mm) of a stainless steel sheet, vinyl chloride resin coated steel sheet or the like which is an elastic member and comprises a main body 41 having a long substantially cylindrical shape a lower side of which is opened and fold to bend portions 42 constituted by folding to bend lower end portions of the main body 41 to outer sides as shown by FIG. 3. As shown by FIG. 1B, the joint cover member 4 presses the sealing member 3 to cover from an outer side and the above-described fold to bend portions 42, 42 are fit to attach to between the above-described constricted portions 5, 5 by operating an elastic force. According to the waterproof structure of a building of Embodiment 1, a through anchor clip 6 is inserted into between the end edge portions of the roof face members 1, 1 along a longitudinal direction of the end edge portion (refer to FIG. 1). The through anchor clip 6 is formed by a metal sheet of a stainless steel sheet, a vinyl chloride resin coated steel sheet or the like similar to the joint cover member 4 and comprises a main body 61 having a section substantially in a channel-like shape an upper side of which is opened and fold to bend portions 62, 62 constituted by folding to bend front ends of both sides of the main body 61 substantially in an angle-like shape. the through anchor clip 6 is locked by the fold to bend portions 13, 13 formed at the two end edge portions of the roof face members 1, 1, a screw 7 is inserted into a screw hole 63 of the main body 61 and the screw 7 is screwed to a backing member 2 provided at a back face of the roof member 1 to press to attach thereto. Further, according to the waterproof structure of a building of Embodiment 1, an attaching metal piece 8 is attached to pinch the joint cover member 4 from outer sides. An attached object 200 provided above the roof face member 1 is attached by the attaching metal piece 8. As an example of the attached object, a solar panel integrated with a solar cell module, a balcony rail, an exterior machine of an air conditioning apparatus, a hot water supply machine or the like can be pointed out. As shown by FIG. 6, the attaching metal piece 8 comprises a pair of metal piece main bodies 81, 81 each having a section in a channel-like shape, two pieces of bolts 83 and two piece of nuts 84 attached to fold to bend pieces 82, 82 opposed to each other at an upper portion of the metal piece main body 81. A number of pieces of the attaching metal pieces 8 necessary for attaching the attached object are attached. For example, in the case of a solar panel, four pieces of the attaching metal pieces 8 are attached per one sheet of the panel. (Operation of Embodiment 1) According to the waterproof structure of a building of Embodiment 1 constituted as described above, the sealing member 3 is attached to close the interval between the end edge portions of the roof base members 1, 1, and the joint cover member 4 is formed by an elastic material and presses the sealing member 3 to cover from the outer side to fit to attach to between the above-described constricted portions 5, 5 by operating an elastic force. As a result, the sealing member 3 is brought into close contact with the end edge portions of the roof face members 1, 1 and therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, the sealing member 3 is made to be watertight by only fitting the joint cover member 4 to the constrained portions 5, 5 and therefore, waterproof construction operation is facilitated and high construction reliability is achieved without special technique. At this occasion, there is not an opening or the like of a fin-like sealing member by an ageing deterioration as in the prior art, which is excellent in durability. Further, the through anchor clip 6 is inserted into between the end edge portions of the roof face members 1, 1 along the longitudinal direction of the end edge portion and the through anchor clip 6 is locked by the two end edge portions of the roof members 1, 1 and is pressed to attach to the backing member 2 by the screw 7. Therefore, when the roof face members 1, 1 are tackedly laid to adjust positions thereof and thereafter, the through anchor clip 6 is fixedly attached, the roof face member 1 can actually be fixed to the backing member 2 and a number of construction steps can be reduced. At this occasion, the screw 7 for fixedly attaching the through anchor clip 6 is covered by the joint cover member 4 and the sealing member 3 and therefore, water is not leaked from the screw hole 63. Furthermore, the attaching metal piece 8 is attached thereto to pinch the joint cover member 4 from the outer side, the attached object provided above the roof face member 1 is attached by the attaching metal piece 8 and therefore, the attached member can easily be attached while ensuring the waterproof structure. Further, the attached object can easily be attached after construction. Modified Examples of Embodiment 1 FIG. 7 through FIG. 9 are sectional views of waterproof structures of a roof according to modified examples of Embodiment 1. Modified Example 1 According to Modified Example 1 shown in FIG. 7, although the shape of the constrained portion 5 of the roof face member 1, the shape of the sealing member 3, the shape of the joint cover member 4, the shape of the anchor clip 6 and the like more or less differ from those of FIG. 1, the shapes are essentially similar thereto. The roof member 1 shown in FIG. 7 is formed by a flat roof main body 11, fold to bend portions 12 constituted by folding to bend both side end edge portions of the roof main body 11 in right angle and fold to bend portion 13 having a semicircular arc shape constituted by being folded to bend to bulge to inner sides at front ends of the fold to bend portions 12. The sealing member is formed in a shape of a thick-walled sheet and disposed a back face of the joint cover member 4 and may integrally formed with the joint cover member 4 or separately therefrom. Although the shape of the joint cover member 4 and the shape of the anchor clip 6 are formed to fix to the shape of the fold to bend portion 13 in the semicircular arc shape of the face member 1, the shapes remain unchanged essentially from the shapes of FIG. 1. Modified Example 2 According to Modified Example 2 shown in FIG. 8, the roof face member 1 is formed by the flat roof main body 11, the fold to bend portion 12 constituted by folding to bend the both side end edge portions of the roof main body 1 in right angle, the fold to bend portion 13 folded to bend to bulge substantially in a U-like shape to an inner side at the front end of the fold to bend portion 12 and a fold to bend portion 14 folded to bend from the fold to bend portion 13 in the U-like shape in right angle to direct to the upper side. The sealing member 3 is constituted by a thick-walled section substantially in C-like shape a lower side of which is opened, inner sides of front ends of both sides thereof are constituted by a fin-like shape to be brought into contact with the inner side of the fold to bend portion 14 of the roof face member 1. The joint cover member 4 is constituted by a section substantially in a C-like shape a lower side of which is opened and an opening end portion thereof is locked by the fold to bend portion 13 in the U-like shape of the roof face member. The anchor clip 6 is constituted by a section substantially in a channel-like shape an upper side of which is opened, front end portions on both sides thereof are folded to bend to outer sides in a hook-like shape and the anchor clip 6 is locked by catching front end portions thereof in the hook-like shape by front ends of the fold to bend portions 14 of the roof face member 1 different from those of Embodiment 1 and Modified Example 1 thereof, mentioned above. Modified Example 3 According to Modified Example 3 shown in FIG. 9, other than the sealing member 3 is constituted by shapes substantially the same as those of Embodiment 1 shown in FIG. 1. The sealing member 3 of FIG. 9 is constituted by a thick-wall section substantially in a C-like shape inner sides of front ends of both sides of which-are constituted by a fin-like shape and is brought into contact with inner sides of the fold to bend portions 14 of the roof face member 1. Further, Modified Examples 1 through 3 shown in FIG. 7 through FIG. 9 are constructed by constitutions essentially similar to that of Embodiment 1 and achieve operation the same as that of Embodiment 1 and therefore, an explanation thereof will be omitted. Embodiment 2 FIG. 10 shows Embodiment 2 of the invention, FIG. 10A is a sectional view of a roof for attaching a sealing member and FIG. 10B is a sectional view showing a waterproof structure of a roof. Embodiment 2 is a waterproof structure of a building provided with the sealing member 3 between the contiguous roof face members 1, 1 of the building. As shown by FIG. 10A, the sealing member 3 is constituted by a section substantially in a shape of a square cylinder and includes a hollow portion 30 and is attached to between the end edge portions of the roof face members 1, 1 by being deformed to press to crush the hollow portion 30 to make the interval between the end edge portions of the roof face members 1, 1 watertight. According to the waterproof structure of the building, the roof face member 1 is constituted by a shape similar to that of Embodiment 1 and is formed by the flat roof main body 11, the fold to bend portions 12 constituted by folding to bend the both side end edge portions of the roof main body 11 in right angle and the fold to bend portions 13 constituted by folding to bend front ends of the fold to bend portions 12 substantially in a U-like shape. The end edge portion (joint portion) between the roof face members 1, 1 is provided with the sealing member 3 and the joint cover member 4, the joint cover member 4 covers the sealing member 3 from the outer side to press to crush the hollow portion 30 and is fixed to the constrained portions 5 between the end edge portions of the contiguous roof face members 1, 1. Further, the through anchor clip 6 is inserted to between the end edge portions of the roof face members 1, 1 along the longitudinal direction of the end edge portion similar to Embodiment 1 (refer to FIG. 10). The through anchor clip 6 is constituted by a section substantially in a channel-like shape the upper side of which is opened, front ends of both sides thereof are folded to bend substantially in an angle-like shape and locked by the fold to bend portions 13, 13 in the U-like shape formed at the both end edge portions of the roof face members 1, 1 and the anchor clip 6 is screwed to press to attach to the backing member 2 provided at the back face of the face member 1 by using the screw 7. (Operation of Embodiment 2) According to the waterproof structure of the building of Embodiment 2 constituted in this way, the sealing member 3 includes the hollow portion 30 and is attached to between the roof face members 1, 1 by being deformed to press to crush the follow portion 30 to make the interval between the roof face members 1, 1 watertight and therefore, there is constructed a highly reliable waterproof structure which is difficult to leak water. Even in an arrangement having a stepped difference between the roof face members 1, 1, the sealing member 3 can deal therewith by the same member, further, even when a stepped difference is produced between the roof face members 1, 1 by construction error or the like, the stepped difference can be absorbed thereby. Further, the sealing member 3 and the joint cover member 4 are provided at the end edge portions between the roof face members 1, 1, the joint cover member 4 covers the sealing member 3 from the outer side and is fit to between the end edge portions of the contiguous roof face members 1, 1 and therefore, the sealing member 3 is not exposed directly to outer air. Therefore, a deterioration by the sealing member 3 by direct sunlight or the like is prevented and durability thereof is improved. (Embodiment 3) FIG. 11 and FIGS. 12A-D show Embodiment 3 of the invention, FIG. 11 is an explanatory view of attaching an eaves side cover provided between a roof and a cover above a gutter, FIG. 12A is a sectional view of an eaves of the roof, FIG. 12B is a sectional view enlarging a portion b, FIG. 12C is a sectional view enlarging a portion c and FIG. 12D is a sectional view enlarging a portion d. According to Embodiment 3, roof face members 101, 101, 101 . . . are contiguously attached to an exterior side of an upper face of a building and a joint cover member 103 is provided between end edge portions of the roof face member 101 opposed to each other. A cover member of the invention is an eaves side cover member 102, the eaves side cover member 102 includes a flat plate portion 121 and fitting portions 122, 122 integrated to a lower face of one end side thereof, having a section substantially in an inverse U-like shape and having a shape of narrowing an opening side thereof, and opposed sides of the fitting portions 122, 122 are provided with a jointing portion 124 folded to bend downwardly in a channel-like shape, and notches 125, 125 in a channel-like shape as a space for jointing with a cover 104 above a gutter by using a rivet 105. Further, end portions of the eaves side cover member 2 orthogonal to the fitting portions 122, 122 and the jointing portion 124 and the like include raised portions 123, 123 in a channel-like shape. Explaining further in details in reference to FIG. 11, FIGS. 12A-D, the jointing portion 124 of the eaves side cover member 102 is positioned between a flat plate portion 141 and a raised portion 142 of the cover 104 above a gutter, and the fitting portions 122, 122 integrated to the lower face of the eaves side cover member 102, having the section substantially in the inverse U-like shape and narrowing the opening side are fit to constrained portions 132, 132 of the joint cover members 103 of the roof face members 101. The roof face member 101 and the joint cover member 103 are formed by metal sheets (sheet thickness: 0.1 through 0.6 mm) of stainless steel sheets, vinyl chloride resin coated steel sheets or the like. Similarly, also the eaves side cover member 2 and the fitting portions 122, 122 integrated to the lower face, having the section substantially in the inverse U-like shape and narrowing the opening side are formed by metal sheets (sheet thickness: 0.3 through 0.6 mm) of stainless steel sheets, vinyl chloride resin coated steel sheet or the like which are elastic members, and as shown by FIG. 11, and as shown by FIG. 11, fold to bend portions 221, 221 are fit to attach between the constrained portions 132, 132 of the joint cover members 3 by operating an elastic force. FIGS. 12A-D are sectional views showing an eaves side on a downstream side of water as shown by an arrow mark of a flow direction in the drawing, the roof face member 101 is formed by the above-described steel sheet above a backing member 112 comprising a roof board having a plate thickness of 12 mm and a waterproof layer 111 of asphalt roofing and is supported by a ceiling joist 115 and a rafter 114. A gutter 143 is attached to a side of the end edge portion (downstream side of water on the left side of the drawing) of the roof face member 101 and a parapet 106 which is an eaves side decorative sheet is attached thereto. An eptsealer (sound absorbing material) 146 is laid at a lower portion of the gutter 143 and an eaves side panel 147 is attached further therebelow. As shown by FIG. 12D, according to the eaves side cover 102 of the invention, on the side of the end edge portion of the roof face member 101, one end side of the gutter 143 is sealed by a butyl tape 107 to prevent water and fixed to the end edge portion of the roof face member 101 by the rivet 105. Further, the fitting portion 122 of the eaves side cover member 102 is fit to attach to the joint cover member 103 of an inner side (right side of FIG. 12) of an eaves side cap 131 from thereabove. Further, as shown by FIG. 12C, other end side on the exterior side of the gutter 143 is sealed to prevent water by the cover member 4 above the gutter, the jointing portion 124 on the exterior side of the eaves side cover member 102 and the butyl tape 107 and is fixed by the rivet 105. Further, as shown by FIG. 12B, the raised portion 142 of the cover member 104 above the gutter and an upper end portion 161 of the parapet 106 are sealed to prevent water by a trim 145 above the eaves. According to the waterproof structure of a building of Embodiment 1 constituted in this way, the eaves side cover member 102 comprises the flat plate portion 121 and the fitting portions 122, 122 integrated to the lower face, having the section substantially in the inverse U-like shape and having the shape narrowing the opening side, and the fitting portions 122, 122 are fit to attach to the constrained portions 132, 132 of the joint cover members 103 provided between the end edge portions of the roof face members 101, 101, 101 . . . attached contiguously and opposed to each other and having projected portions having constrained portions. As a result, the eaves side cover member 102 is fitted to attach to the constrained portions of the joint cover member 103 provided at the joint portion of the roof face member 101 an therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, waterproof construction operation is facilitated. At this occasion, according to the eaves side cover member 102 of the invention, the fitting portion 122, 122 are constituted by metal elastic members and therefore, there is not an opening or the like which is brought about in the fin-like sealing member by an ageing deterioration as in the prior art, which is excellent in durability. Further, although the eaves side cover member 102 and the cover member 104 are fixed by the rivet 105, a nail head thereof is not exposed, which is excellent in design performance and waterproof performance. FIGS. 13A-B and FIGS. 14A-B show Embodiment 4 of the invention, FIG. 13A-B illustrate explanatory views of attaching a cover on an upstream side of water provided between a roof on an upstream side of water and a joint cover, FIG. 14A is a sectional view of the roof on the upstream side of water and FIG. 14B is a sectional view enlarging a portion b. According to Embodiment 4, the roof face members 101, 101, 101, . . . are contiguously attached to the exterior side of the upper face of a building and the joint cover member 103 is provided between the end edge portions of the roof face members 101, 101 opposed to each other. A cover member of the invention is a cover member 102b on an upstream side of water, and the cover member 102b on the upstream side of water is provided with a section in an L-like shape by a flat plate portion 121b and a raised portion 123b and includes fitting portions 122b, 122b integrated to the lower face thereof, having a section substantially in an inverse U-like shape and having a shape narrowing an opening side thereof. Explaining further in details in reference to FIGS. 13A-B and FIG. 14A-B, a sealing member 108 of denatured silicone or the like is coked by a coking gun 108a at a butting portion 101c of butting raised portions 132b on the upstream side of water of the joint cover member 103 provided between the end edge portions of the roof face members 101, 101 opposed to each other and raised portions 101b of the roof face members 101. Fitting portions 122b, 122b of the cover members 102b on the upstream side of water are fit to the constrained portions 132, 132 of the joint cover members 103 thereabove. The cover member 102b on the upstream side of water is formed by a metal sheet (sheet thickness: 0.3 through 0.6 mm) of a stainless steel sheet, a vinyl chloride resin coated steel sheetor the like similar to the roof face member 101. Similarly, also the fitting portions 122b, 122b integrated to the lower face of the cover 102 on the upstream side of water, having the section substantially in the inverse U-like shape and narrowing the opening side are formed by metal sheets (sheet thickness: 0.3 through 0.6 mm) of stainless steel sheets, vinyl chloride resin coated steel sheets or the like which are elastic members and as shown by FIG. 13, fold to bend portions 221b, 221b are fit to attach to the constrained portions 131, 131 of the joint cover member 3 by operating an elastic force. FIGS. 14A-B are sectional views showing the eaves side on the upstream side of water as shown by an arrow mark of a flow direction of the drawing, the roof face member 1 is formed by the above-described steel sheet above the backing member 112 comprising the roof board having the plate thickness of 12mm and the waterproof layer 111 of asphalt roofing and supported by the ceiling joist 115 and the rafter 114. The side of the end edge portion (upstream side of water on the left side of the drawing) of the roof face member 101 is attached with the parapet 106 which is the eaves side decorative member. The eaves side panel 147 is attached therebelow. According to the cover member 102 on the upstream side of water of the invention, on the side of the end edge portion of the roof face member 101, as shown by enlarging the portion a in FIG. 14B, the raised portion of the roof face member 101, the raised portion 123b of the cover member 102b on the upstream side of water, and the upper end portion 161 of the parapet 106 are pinched by the trim 145 above the eaves to seal to prevent water. According to the waterproof structure of a building of Embodiment 4 constituted in this way, the cover member 102b on the upstream side of water comprises the flat plate portion 121b and the fitting portions 122b, 122b integrated to the lower face, having the section substantially in the inverse U-like shape and having the shape narrowing the opening side and the fitting portions 122b, 122b are fit to attach to the constrained portions 132, 132 of the joint cover members 3 provided between the end edge portions of the roof face members 101, 101, 101 . . . attached contiguously and including projected portions having constrained portions. As a result, the cover member 2b on the up stream side of water is fit to attach to the constrained portions 132, 132 of the joint cover member 103 provided at the jointing portion of the roof face member 101 and therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, waterproof construction operation is facilitated. At this occasion, according to the cover member 102b on the upstream side of water of the invention, the fitting portions 122b, 122b are constituted by metal elastic member sand therefore, there is not an opening or the like brought about at the fin-like sealing member by an ageing deterioration as in the prior art, which is excellent in durability. Although an explanation has been given of embodiments of the invention in reference to drawings as described above, the invention is not limited to the embodiments but even when design thereof is changed within a range which does not change the gist of the invention, the change is included in the invention. For example, although according to the above embodiments, the contiguous face members are the roof face members 1, 1, that is arranged on a roof 300 of a building 310 as shown in FIG. 17, the face members may form joint portions outside of the building 310 of an outer wall 320, a balcony floor 330, a surrounding of an opening 340 and the like. In addition, as shown in FIG. 18, the building 310 may be a simple structure having a roof 350 and pillars 360 for supporting the roof 350, such as a barn or a depository. The roof structure may be a structure as shown in FIGS. 15 and 16. The roof structure 500 shown in FIGS. 15 and 16 includes face members 502 having end edge portions 504, an anchor clip 506, a sealing member 508, and a joint covering member 510. The sealing member 508 is integrally attached on an inner surface of the joint covering member 510. The sealing member 508 is made of a mixture of an EPDM (ethylene-propylene terpolymer) foamed material and a butyl rubber. An adhesive material 512 made of a butyl rubber is attached on the lower side of the joint covering member 510. The anchor clip 506 is inserted into a gap between the end edge portions 504 so as to fit with constrained portions 504a of the end edge portions 504. FIG. 16 shows an assembled state of the roof structure 500. As shown in FIG. 16, the face members 502 are disposed onto the roof plate 514 together with the anchor clip 506. The face members 502 are arranged so that the joint portion therebetween extends along a beam member 516 for supporting the roof plate 514. The anchor clip 506 sandwiched between the end edge portions 504 is disposed along the beam member 516 and is fixed to the beam member 516 by using a bolt 518. The joint cover member 510 is disposed on the joint portion between the end edge portions 504 engaging with the constrained portions 504a from the exterior acting elastic force between the end edge portions 504. By this elastic force, the sealing member 508 is deformed so as to fit on the end edge portions 504, thereby sealing the clearance between the end edge portions 504. At the same time, the adhesive material 512 is tightly adhered to the end edge portions 504, thereby to securely seal the joint portion. Therefore, the roof structure 500 can attain a favorable sealing performance and also prevent a degradation of the sealing performance resulting from thermal deterioration of the sealing member 508 by sunlight or deterioration of the sealing member 508 by repeated freezing and melting due to a snow coverage. According to the invention, the joint cover member covers the sealing member from the outer side to fit to between the constrained portions of the face members by operating the elastic force and therefore, the sealing member is pressed to the end edge portions of the face members, there is constituted a highly reliable waterproof structure which is difficult to leak water and also waterproof construction operation is facilitated. At this occasion, there is not an opening or the like of the fin-like sealing member by an ageing deterioration, which is excellent in durability. According to the invention, further, also the anchor clip is covered by the joint cover and the sealing member and therefore, water is not leaked from the screw hole of the anchor clip. According to the invention, further, the attaching metal piece is attached to pinch the joint cover member from the outer side, the attached object provided above the face member is attached by the attaching metal piece and therefore, the attached object can easily be attached while ensuring the waterproof structure.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a waterproof structure of a building using a cover member. 2. Background Art Generally, an outside joint portion of a building of a roof, a balcony floor, an outer wall, a surrounding of an opening or the like is provided with a sealing member to constitute a waterproof structure. A sealing member described in Japanese Patent No. 2519660 is arranged at inside of a joiner for connecting to engage roof sheets and constituted by forming a sealing member main body in an inverse U-like shape by an elastic material and forming a single or a plurality of fin-like sealing valves at positions on an inner side of the sealing member main body opposed thereto. According to the above-described sealing member, the sealing valve squeezes the roof sheet members to eliminate a clearance therebetween to thereby prevent invasion of water. Further, according to a folded sheet roof described in JP-A-7-34609, there is provided a waterproof structure of the folded sheet roof attaching a drip or the like to an attaching member installed above bulged shape head portions of contiguous ridge portions and an attaching apparatus constituted by integrally connecting a locking member fit to attach to constrained portions between valley portions interposed by the contiguous ridge portions and the attaching member. According to the above-described waterproof structure of the folded sheet roof, the attaching apparatus is formed integrally therewith and therefore, fabrication cost can be reduced, there is not a concern of breaking joint between constituent members of the attaching apparatus even when a strong wind of typhoon or the like is brought about and the drip or the like can solidly be fixed to the folded sheet roof.
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<SOH> SUMMARY OF THE INVENTION <EOH>However, according to the sealing member described in Japanese Patent No. 2519660, there poses a problem that when the fin-like sealing valve is subjected to ageing deterioration, the sealing valve is opened by a reduction in an elastic force and water is liable to leak. Further, according to the waterproof structure of the folded sheet roof described in JP-A-7-34609, when an interval between the bulged shape head portions of the contiguous ridge portions is widened, a volume of the attaching apparatus is increased to increase cost. Hence, it is an object of the invention to provide a cover member and a waterproof structure of a building using a cover member which resolve the above-described problem, in which water is difficult to leak and which is highly reliable at low cost. The invention provides a waterproof structure of a building, including: at least two face members each having an end edge portion, the at least two face members disposed on an exterior of the building so that the end edge portions are opposed to each other; a sealing member disposed between the end edge portions; and a joint covering member that is elastically deformable and disposed between the end edge portions; wherein the end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween; the sealing member is disposed between the end edge portions to close the gap between the end edge portions; the joint covering member covers and presses the sealing member from an exterior side; and the joint covering member is attached to the constrained portions acting elastic force between the constrained portions. Preferably, the waterproof structure further includes an anchor clip extending along the end edge portions; wherein the anchor clip is inserted into the gap being engaged with the end edge portions to be pressed and fitted on a backing member that is disposed on a back side of the face member. Preferably, the waterproof structure further includes an attaching clip for attaching an attached object to be disposed on the face member; wherein the attaching clip is attached to pinch the joint cover member from an outer side thereof. Preferably, the waterproof structure includes: a cover member having a plate portion and a fitting portion integrated to a lower face of the plate portion; wherein the fitting portion is attached to the constrained portions. Preferably, at least a part of the constrained portions are disposed at an eave side of the building; and the cover member covers an eave of the building. Preferably, at least a part of the constrained portions are disposed on a water upstream side of the building; and the cover member covers the water upstream side of the building. Preferably, the waterproof structure includes: an adhesive material attached on the sealing member, for adhering to the end edge portions. Preferably, the fitting portion includes a cross section having a substantially U-like shape with a narrowed opening. The invention may provide a building, including: a roof; a supporting member that supports the roof; at least two face members each having an end edge portion, the at least two face members disposed on an exterior of the building so that the end edge portions are opposed to each other; a sealing member disposed between the end edge portions; and a joint covering member that is elastically deformable and disposed between the end edge portions; wherein the end edge portions are folded to protrude exteriorly and have constrained portions for narrowing a gap therebetween; the sealing member is disposed between the end edge portions to close the gap between the end edge portions; the joint covering member covers and presses the sealing member from an exterior side; and the joint covering member is attached to the constrained portions acting elastic force between the constrained portions. According to one aspect of the invention, the sealing member is attached to close the gap between the end edge portions of the face members, and the joint cover member is formed by the elastic deformable member to press the sealing member to cover from the outer side and fit to attach to between the constrained portions by operating the elastic force. As a result, the sealing member is brought into close contact with the end edge portions of the press members and therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, waterproof construction operation is facilitated. At this occasion, there is not opening or the like of a fin-like sealing member by an ageing deterioration, which is excellent in durability. According to another aspect of the invention, further, the anchor clip is inserted to between the end edge portions of the face members along the longitudinal direction of the end edge portion, the anchor clip is made to be able to be pressed to attach to the backing member at the back face of the face member by being locked by the two end edge portions of the face members and therefore, when the anchor clip is fixedly attached to the backing member by using the screw or the like after tackedly laying the face members. the face members can actually be fixed to the backing member. At this occasion, the screw for fixedly attaching the anchor clip is covered by the joint cover and the sealing member and therefore, water is not leaked from the screw hole. According to another aspect of the invention, further, the attaching clip is attached to pinch the joint cover member from an outer side, the attached object provided above the face member is attached by the attaching metal piece and therefore, the attached object can easily be attached while ensuring the waterproof structure. According to another aspect of the invention, the cover member includes the plate portion and the fitting portion integrated to the low face, having the section substantially in the inverse U-like shape and having the shape narrowing the opening side, and the fitting portion is made to be fit to attach to the constrained portion. As a result, the cover member is fit to attach to the constrained portion and therefore, there is constituted a highly reliable waterproof structure which is difficult to leak water. Further, waterproof construction operation is facilitated. At this occasion, there is not an opening or the like brought about in the fin-like sealing member by an ageing deterioration as in the prior art, which is excellent in durability. According to another aspect of the invention, further, the cover member is the eaves side cover member and therefore, the cover member may only be fit to attach to between the member on the eaves side and the member including the projected portion having the constrained portion provided at the joint portion of the face members and waterproof construction operation is facilitated. Further, a nail head is not exposed, which is excellent in design performance. According to another aspect of the invention, the cover member is on the water upstream side and therefore, the cover member may only be fit to attach to between the member on the water upstream side and the member including the projected portion having the constrained portion provided at the joint portion of the face members and waterproof construction operation is facilitated.
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20040630
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20100406
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20050127
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64885.0
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QUAST, ELIZABETH A
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WATERPROOF STRUCTURE OF BUILDING
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UNDISCOUNTED
| 0
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ACCEPTED
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10,880,378
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ACCEPTED
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Pharmaceutically active compounds and methods of use
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The present invention relates to certain imine-substituted heterocyclic compounds, and methods of treatment and pharmaceutical compositions that utilize or comprise one or more such compounds. Compounds of the invention are particularly useful for the treatment or prophylaxis of neurological injury and neurodegenerative disorders.
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1. A compound of the following Formula I: wherein Z is sulfur, oxygen, carbon or nitrogen; m and n are each independently an integer from 0 to 4, and the sum of m and n is at least 2; each X is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkylsilyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted alkoxy; substituted or unsubstituted alkylthio; substituted or unsubstituted alkylamino; substituted or unsubstituted alkylsulfinyl; substituted or unsubstituted alkylsulfonyl; substituted or unsubstituted aralkyl; substituted or unsubstituted carbocyclic aryl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; p is an integer of from 0 to 14; and pharmaceutically acceptable salts thereof. 2. A compound of claim 1 wherein Z is carbon. 3. A compound of claim 1 wherein p is from 0 to 4. 4. A compound of claim 1 wherein the compound is of the following Formula Ia: wherein Z is —CH2—, —S—, —O— or —N—; each X is independently a substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted alkoxy; substituted or unsubstituted alkylthio; substituted or unsubstituted aminoalkyl; substituted or unsubstituted alkylsulfinyl; substituted or unsubstituted alkylsulfonyl; substituted or unsubstituted carbocyclic aryl; substituted or unsubstituted aralkyl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; p′ is an integer of from 0 to 10; and pharmaceutically acceptable salts thereof. 5. A compound of claim 1 wherein the compound is of the following Formula Ib: wherein X is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted alkoxy; substituted or unsubstituted alkylthio; substituted or unsubstituted aminoalkyl; substituted or unsubstituted alkylsulfinyl; substituted or unsubstituted alkylsulfonyl; substituted or unsubstituted carbocyclic aryl; substituted or unsubstituted aralkyl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; p″ is an integer of from 0 to 10; and pharmaceutically acceptable salts thereof. 6. A compound of claim 1 wherein the compound is of the following Formula Ic: wherein W and Y are each independently substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted alkoxy; substituted or unsubstituted alkylthio; substituted or unsubstituted aminoalkyl; substituted or unsubstituted alkylsulfinyl; substituted or unsubstituted alkylsulfonyl; substituted or unsubstituted carbocyclic aryl; substituted or unsubstituted aralkyl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; and pharmaceutically acceptable salts thereof. 7. A compound of claim 6 wherein W and Y are each independently substituted or unsubstituted alkyl, substituted or unsubstituted carbocyclic aryl or substituted or unsubstituted aralkyl or substituted or unsubstituted heteraromatic. 8. A compound of claim 1, 4, 5 or 6 wherein the X, W and Y groups may be optionally substituted by one or more halogen; cyano; hydroxyl; nitro; azido; alkanoyl; carboxamido; alkyl; alkenyl; alkynyl; alkylsilyl; alkoxy groups; aryloxy; alkylthio; alkylsulfinyl; alkylsulfonyl; alkylamino; carbocyclic aryl; aralkyl; and heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms. 9. A compound of claim 2 wherein the sum of m and n is 3. 10. A compound of claim 1 that is N-carboximidamide-r-2, c-6-di(4-methylphenyl)piperidine; N-carboximidamide-r-2, c-6-di(4-isopropylphenyl)piperidine; N-carboximidamide-r-2, t-6-di(4-methylphenyl)piperidine; N-carboximidamide-r-2, c-6-diphenylpyrrolidine; and pharmaceutically acceptable salts thereof. 11. A compound of the following Formula II: wherein Z is sulfur, oxygen, carbon or nitrogen; m and n are each independently an integer from 0 to 4, and the sum of m and n is at least 2; each X is independently substituted or unsubstituted alkyl; substituted or unsubstituted alkylsilyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted alkoxy; substituted or unsubstituted alkylthio; substituted or unsubstituted alkylamino; substituted or unsubstituted alkylsulfinyl; substituted or unsubstituted alkylsulfonyl; substituted or unsubstituted carbocyclic aryl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; R, R1 and R2 are each independently hydrogen; hydroxy; substituted or unsubstituted alkanoyl; substituted or unsubstituted alkanoyloxy; substituted or unsubstituted alkyl; substituted or unsubstituted alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted alkoxy; substituted or unsubstituted alkylthio; substituted or unsubstituted alkylamino; substituted or unsubstituted alkylsulfinyl; substituted or unsubstituted alkylsulfonyl; substituted or unsubstituted carbocyclic aryl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms, with at least one of R, R1 and R2 being other than hydrogen; and pharmaceutically acceptable salts thereof. 12. A compound of claim 11 wherein the X, R, R1 and R2 groups each may be optionally substituted by one or more halogen; cyano; hydroxyl; nitro; azido; alkanoyl; carboxamido; alkyl; alkenyl; alkynyl; alkylsilyl; alkoxy groups; aryloxy; alkylthio; alkylsulfinyl; alkylsulfonyl; alkylamino; carbocyclic aryl; aralkyl; or heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms. 13. A compound of claim 11 wherein R, R1 and R2 are hydrogen; hydroxy; substituted or unsubstituted alkanoyl; substituted or unsubstituted alkanoyloxy; alkyl; alkenyl; alkynyl; alkoxy; alkylthio; alkylamino; alkylsulfinyl; alkylsulfonyl; substituted or unsubstituted carbocyclic aryl; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms. 14. A compound of claim 11 or 13 wherein at least one of R and R1 is other than hydrogen, and R2 is hydrogen. 15. A compound of claim 11 wherein the sum of n and m is 3, 4 or 5. 16. A compound of claim 11 that is N-(N′-phenyl)carboximidamide-r-2, c-6-diphenylpiperidine. 17. An optically active stereoisomer of a compound of any one of claims 1-16. 18. A compound of the following formula: wherein Z, X, m, n and p are the same as defined in claim 1; and salts of said compounds. 19. A compound of claim 18 wherein the sum of m and n is 3, 4 or 5. 20. A method of treating a nerve degeneration disease comprising administering to a mammal suffering from or susceptible to said disease a therapeutically effective amount of a compound of any of claims 1-17. 21. A method of treating Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome or Korsakoff's disease, Cerebral Palsy, or epilepsy, comprising administering to a mammal suffering from or susceptible to said disease a therapeutically effective amount of a compound of any of claims 1-17. 22. A method of treating or preventing nerve cell death comprising administering to a mammal suffering from or susceptible to nerve cell death a therapeutically effective amount of a compound of any one of claims 1-17. 23. The method of claim 22 wherein the nerve cell death is caused by hypoxia, hypoglycemia, brain or spinal cord ischemia, retinal ischemia, brain or spinal cord trauma, heart attack or stroke. 24. A method of treating a mammal suffering from or susceptible to stroke comprising administering to the mammal a therapeutically effective amount of a compound of any one of claims 1-17. 25. A method of treating a mammal suffering from or susceptible to brain or spinal cord trauma or ischemia, or heart attack comprising administering to the mammal a therapeutically effective amount of a compound of any one of claims 1-17. 26. A method of treating a mammal suffering from or susceptible to neuropathic pain, migraines, shingles, emesis, narcotic withdrawal symptoms or age-dependent dementia, comprising administering to the mammal a therapeutically effective amount of a compound of any one of claims 1-17. 27. A method for treating the consequences of decreased blood flow or nutrient supply to retinal tissue, or retinal ischemia or trauma, or optic nerve injury, comprising administering to a mammal in need of such treatment a therapeutically effective amount of a compound of any one of claims 1-17. 28. A method of treating a mammal suffering from or susceptible to post-surgical neurological deficits or neurological deficits associated with cardiac arrest, comprising administering to the mammal a therapeutically effective amount of a compound of any one of claims 1-17. 29. A pharmaceutical composition comprising a therapeutically effective amount of one or more compounds of any one of claims 1-17 and a pharmaceutically acceptable carrier. 30. A compound of any one of claims 1-17 that is radiolabelled.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to certain imine-substituted heterocyclic compounds, and methods of treatment and pharmaceutical compositions that utilize or comprise one or more such compounds. Compounds of the invention are particularly useful for the treatment or prophylaxis of neurological injury and neurodegenerative disorders. 2. Background Nerve cell death (degeneration) can cause potentially devastating and irreversible effects for an individual and may occur e.g. as a result of stroke, heart attack or other brain or spinal chord ischemia or trauma. Additionally, neurodegenerative disorders involve nerve cell death (degeneration) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome and Korsakoff's disease. Therapies have been investigated to treat nerve cell degeneration and related disorders, e.g., by limiting the extent of nerve cell death that may otherwise occur to an individual. See, e.g., N. L. Reddy et al., J. Med. Chem., 37:260-267 (1994); and WO 95/20950. The compound MK-801 has exhibited good results in a variety of in vivo models of stroke. See B. Meldrum, Cerbrovascular Brain Metab. Rev., 2:27-57 (1990); D. Choi, Cerbrovascular Brain Metab. Rev., 2:105-147 (1990). See also Merck Index, monograph 3392, 11th ed., 1989. For example, MK-801 exhibits good activity in mouse audiogenic tests, a recognized model for evaluation of neuroprotective drugs. See, e.g., M. Tricklebank et al., European Journal of Pharmacology, 167:127-135 (1989); T. Seyfried, Federation Proceedings, 38(10):2399-2404 (1979). However, MK-801 also has shown toxicity and further clinical development of the compound is currently uncertain. See J. W. Olney et al., Science, 244:1360-1362 (1989); W. Koek et al., J. Pharmacol. Exp. Ther., 252:349-357 (1990); F. R. Sharp et al., Society for Neuroscience Abstr., abstr. no. 482.3 (1992). It thus would be highly desirable to have new neuroprotective agents, particularly agents to limit the extent or otherwise treat nerve cell death (degeneration) such as may occur with stroke, heart attack or brain or spinal cord trauma, or to treat neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome and Korsakoff's disease. SUMMARY OF THE INVENTION In a first aspect, the present invention provides imine-substituted compounds of the following Formula I: wherein Z is sulfur, oxygen, carbon or nitrogen; m and n are each independently an integer from 0-to 4, and the sum of m and n is at least 2, preferably is 3, 4, 5 or 6, more preferably 3, 4 or 5; each X is independently substituted or unsubstituted alkyl preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylsilyl preferably having 1 to about 20 carbon atoms and 1 or more Si atoms; substituted or unsubstituted alkenyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkynyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkoxy preferably having from 1 to about 20 carbon atoms, including haloalkoxy; substituted or unsubstituted alkylthio preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylamino preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfinyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfonyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted carbocyclic aryl preferably having at least about 6 ring carbon atoms; substituted or unsubstituted aralkyl preferably having from 7 to about 18 carbons; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; p is an integer equal to 0 (where the ring is substituted only by the depicted —C(═NH)NH2 substituent) to 14, more typically from 0 to about 4; and pharmaceutically acceptable salts thereof. Substituted or unsubstituted methylene (—CH2—) is a generally preferred Z ring member. Generally preferred X groups include substituted and unsubstituted alkyl, substituted and unsubstituted alkylsilyl, substituted and unsubstituted alkenyl, substituted and unsubstited alkynyl, substituted and unsubstituted alkylthio, substituted and unsubstituted alkylamino, substituted and unsubstituted alkylsulfinyl, substituted and unsubstituted alkylsulfonyl, substituted and unsubstituted aralkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaromatic or heteroalicyclic groups. Particularly preferred X groups included substituted and unsubstituted alkyl and substituted and unsubstituted carbocyclic aryl, particularly substituted and unsubstituted naphthyl or phenyl such as naphthyl or phenyl substituted by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio and ethylthio, and alkylsilyl preferably having 1 to about 15 carbon atoms. It is understood that the imine-substituted ring nitrogen shown in the above formula generally would not be substituted by an X group. It is further understood that the ring methylene (CH2) groups (which include Z where Z is carbon) of the above Formula I will include only a single hydrogen if the methylene unit is mono-substituted by an X group, i.e. the methylene unit will be (CHX), or the methylene unit will contain no hydrogens if di-substituted by X groups, i.e. the methylene unit will be (CXX). It is also understood the range of p values will depend in part on the sum of m and n as well as the valence of the Z ring substituent. Thus, for example, if the sum of m and n is 4 and without limitation on the Z ring member, p will be an integer of from 0 to 10, but if Z is specified to be oxygen, then p will be an integer of from 0 to 8, or if Z is nitrogen then p will be an integer of from 0 to 10. Generally preferred compounds of Formula I include six-member ring compounds (i.e. where the sum of m and n above is four), particularly compounds of the following Formula Ia: wherein Z and X are each the same as defined above for Formula I; p′ is an integer of from 0 (where the ring is substituted only by the —C(═NH)NH2 substituent) to 10, more typically from 0 to about 4; and pharmaceutically acceptable salts thereof. Particularly preferred compounds of Formula I are substituted piperidines of the following Formula Ib: wherein X is the same as defined above for Formula I; p″ is an integer of from 0 (where the ring is substituted only by the depicted imine) to 10, more typically from 0 to about 4; and pharmaceutically acceptable salts thereof. Generally preferred W and Y groups include substituted and unsubstituted alkyl, substituted and unsubstituted alkylsilyl, substituted and unsubstituted alkenyl, substituted and unsubstituted alkynyl, substituted and unsubstituted alkylthio, substituted and unsubstituted alkylamino, substituted and unsubstituted alkylsulfinyl, substituted and unsubstituted alkylsulfonyl, substituted and unsubstituted aralkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaromatic or heteroalicyclic groups. Particularly preferred W and Y groups included substituted and unsubstituted alkyl and substituted and unsubstituted carbocyclic aryl, particularly substituted and unsubstituted naphthyl or phenyl such as naphthyl or phenyl substituted by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio, and alkylsilyl preferably having 1 to about 15 carbon atoms. In a second aspect, imine-substituted compounds are provided that are substituted by a group other than hydrogen on the imine or adjacent non-cyclic nitrogen. Preferred are compounds of the following Formula II: wherein Z, X, p, m and n are the same as defined above for Formula I; R, R1 and R2 are each independently hydrogen; hydroxy; substituted or unsubstituted alkanoyl having from 1 to about 20 carbon atoms; substituted or unsubstituted alkanoyloxy having from 1 to about 20 carbon atoms; substituted or unsubstituted alkyl preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkenyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkynyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkoxy preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylthio preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylamino preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfinyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfonyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted carbocyclic aryl having at least about 6 ring carbon atoms; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms, with at least one of R, R1 and R2 being other than hydrogen; and pharmaceutically acceptable salts thereof. Preferred compounds of Formula II include six-member ring compounds (sum of m and n above is four), particularly compounds of the following Formula IIa: wherein Z and X are each the same as defined above for Formula I; p is an integer of from 0 to 10, more typically 0 to about 4; R, R1 and R2 are each the same as defined above for Formula II; and pharmaceutically acceptable salts thereof. Substituted piperidine compounds are generally preferred, i.e. where Z is carbon. Also preferred are compounds of Formula II that have at least two ring substituents (p≧2 in Formula II), particularly 2,6-substituted compounds of Formula IIa, such as the following piperidine compounds of Formula IIb: wherein W and Y are the same as defined above for Formula Ic; R, R1 and R2 are each the same as defined above for Formula II; and pharmaceutically acceptable salts thereof. Generally preferred X, W and Y groups of compounds of Formula II, IIa and IIb include substituted and unsubstituted alkyl, substituted and unsubstituted alkylsilyl, substituted and unsubstituted alkenyl, substituted and unsubstituted alkynyl, substituted and unsubstituted alkylthio, substituted and unsubstituted alkylamino, substituted and unsubstituted alkylsulfinyl, substituted and unsubstituted alkylsulfonyl, substituted and unsubstituted aralkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaromatic or heteroalicyclic groups. Particularly preferred X, W and Y groups of compounds of Formula II, IIa and IIb include substituted and unsubstituted alkyl and substituted and unsubstituted carbocyclic aryl, particularly substituted or unsubstituted naphthyl or phenyl such as naphthyl or phenyl substituted by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio or ethylthio, and alkylsilyl preferably having 1 to about 15 carbon atoms. Preferred R and R1 groups of compounds of Formulae II, IIa and IIb include substituted and unsubstituted carbocyclic aryl and heteroaromatic and heteroalicyclic groups. Particularly preferred R and R1 groups are substituted and unsubstituted naphthyl and phenyl groups, such as naphthyl or phenyl substituted at one or more ring positions by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio. Other preferred R and R1 groups include hydroxy, alkyl, alkenyl, alkynyl, alkoxy, alkylthio, alkylamino, alkylsulfinyl, alkylsulfonyl, substituted or unsubstituted alkanoyl and substituted or unsubstituted alkanoyloxy. Generally preferred are compounds of Formulae II, IIa and IIb are those where at least of one of R and R1 is other than hydrogen, and R2 is hydrogen. As with compounds of Formula I, it is understood with respect to the compounds of Formula II that the depicted imine-substituted ring nitrogen would not be substituted by an X group. It is further understood that the ring methylene groups (CH2) of the above Formula II will include only a single hydrogen if the methylene unit is mono-substituted by an X group, i.e. the methylene unit will be (CHX), or the methylene unit will contain no hydrogens if di-substituted by X groups, i.e. the methylene unit will be (CXX). It is also understood the range of p values will depend in part on the sum of m and n as well as the valence of the Z ring substituent. The invention also includes both racemic mixtures and optically enriched mixtures of chiral compounds of the invention. An optically enriched mixture contains substantially more (e.g. about 60%, 70%, 80% or 90% or more) of one enantiomer or diastereoisomer than the other stereoisomer(s). Preferred optically enriched mixtures contain 97% or more, more preferably 98% or more, even more preferably 99% or more of one enantiomer or diastereoisomer than the other stereoisomer(s). Compounds of the invention are useful for a number of therapeutic applications. In particular, the invention includes methods for treatment and/or prophylaxis of neurological conditions/injuries such as epilepsy, neurodegenerative conditions and/or nerve cell death (degeneration) resulting from e.g. hypoxia, hypoglycemia, brain or spinal chord ischemia, retinal ischemia, brain or spinal chord trauma or post-surgical neurological deficits and the like as well as neuropathic pain. The compounds of the invention are especially useful for treatment of a person susceptible or suffering from stroke or heart attack or neurological deficits relating to cardiac arrest, a person suffering or susceptible to brain or spinal cord injury, or a person suffering from the effects of retinal ischemia or degeneration. Compounds of the invention also are useful to treat and/or prevent various neurodegenerative diseases such as Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Alzheimer's disease, Down's Syndrome, Korsakoff's disease, cerebral palsy and/or age-dependent dementia. Compounds of the invention will be further useful to treat and/or prevent migraines, shingles (herpes zoster), epilepsy, emesis and/or narcotic withdrawal symptoms. Also, in addition to treatment of retinal ischemia and related disorders, the invention provides methods for treatment of optic nerve injury/damage. The treatment methods of the invention in general comprise administration of a therapeutically effective amount of one or more compounds of the invention to an animal, including a mammal, particularly a human. Particularly preferred compounds of the invention exhibit good activity in an anticonvulsant in vivo mouse audiogenic assay e.g. as disclosed in Example 6 which follows, preferably about 20% or more inhibition at a dose of a compound of the invention of 20 mg/kg, more preferably about 50% or more or 70% or more inhibition at a dose of 20 mg/kg in such an anticonvulsant in vivo audiogenic assay. The invention also provides pharmaceutical compositions that comprise one or more compounds of the invention and a suitable carrier for the compositions. The invention further provides methods for preparation of compounds of the invention as well as amine (particularly compounds of Formula III below), N-cyano and other compounds useful as intermediates in those preparative methods. Other aspects of the invention are disclosed infra. DETAILED DESCRIPTION OF THE INVENTION The present invention provides imine-substituted compounds of the following Formulae I and II: wherein Z, X, p, m, n, R, R1 and R2 are as defined above; and pharmaceutically acceptable salts of those compounds. Suitable halogen substituent groups of compounds of Formulae I, Ia, Ib, Ic, II, IIa and IIb as defined above (i.e. compounds of the invention) include F, Cl, Br and I. Alkyl groups of compounds of the invention preferably have from 1 to about 12 carbon atoms, more preferably 1 to about 8 carbon atoms, still more preferably 1 to about 6 carbon atoms, even more preferably 1, 2, 3 or 4 carbon atoms. Methyl, ethyl and propyl including isopropyl are particularly preferred alkyl groups of compounds of the invention. As used herein, the term alkyl unless otherwise modified refers to both cyclic and noncyclic groups, although of course cyclic groups will comprise at least three carbon ring members. Preferred alkylsilyl groups include alkylsilyl having 1 to about 15-18 carbons and 1 or about 2 Si atoms, e.g. a trialkylsilyl group such as a trimethylsilyl, triethylsilyl, a butyl(dimethyl)silyl or tributylsilyl group. Preferred alkenyl and alkynyl groups of compounds of the invention have one or more unsaturated linkages and from 2 to about 12 carbon atoms, more preferably 2 to about 8 carbon atoms, still more preferably 2 to about 6 carbon atoms, even more preferably 2, 3 or 4 carbon atoms. The terms alkenyl and alkynyl as used herein refer to both cyclic and noncyclic groups, although straight or branched noncyclic groups are generally more preferred. Preferred alkoxy groups of compounds of the invention include groups having one or more oxygen linkages and from 1 to about 12 carbon atoms, more preferably from 1 to about 8 carbon atoms, and still more preferably 1 to about 6 carbon atoms, even more preferably 1, 2, 3 or 4 carbon atoms. Preferred substituted alkoxy groups include haloalkoxy such as fluoroalkoxy, e.g. trifluoromethoxy, trifluroethoxy, pentafluoroethoxy and the like. Preferred alkylthio groups of compounds of the invention include those groups having one or more thioether linkages and from 1 to about 12 carbon atoms, more preferably from 1 to about 8 carbon atoms, and still more preferably 1 to about 6 carbon atoms. Alkylthio groups having 1, 2, 3 or 4 carbon atoms are particularly preferred. Preferred alkylsulfinyl groups of compounds of the invention include those groups having one or more sulfoxide (SO) groups and from 1 to about 12 carbon atoms, more preferably from 1 to about 8 carbon atoms, and still more preferably 1 to about 6 carbon atoms. Alkylsulfinyl groups having 1, 2, 3 or 4 carbon atoms are particularly preferred. Preferred alkylsulfonyl groups of compounds of the invention include those groups having one or more sulfonyl (SO2) groups and from 1 to about 12 carbon atoms, more preferably from 1 to about 8 carbon atoms, and still more preferably 1 to about 6 carbon atoms. Alkylsulfonyl groups having 1, 2, 3 or 4 carbon atoms are particularly preferred. Preferred alkylamino groups include those groups having one or more primary, secondary and/or tertiary amine groups, and from 1 to about 12 carbon atoms, more preferably 1 to about 8 carbon atoms, still more preferably 1 to about 6 carbon atoms, even more preferably 1, 2, 3 or 4 carbon atoms. Secondary and tertiary amine groups are generally more preferred than primary amine moieties. Preferred alkanoyl groups have from 1 to about 8 carbons and one or two carbonyl groups, with acetyl (CH3CO) and acyl being preferred. Alkanoyloxy groups preferably contain one, two or more oxygen linkages, one or two carbonyl groups and and from 1 to about 8 carbons. Preferred groups include C1-8C(═O)O—. Suitable heteroaromatic substituent groups of compounds of the invention contain one or more N, O or S atoms and include, e.g., coumarinyl including 8-coumarinyl, quinolinyl including 8-quinolinyl, pyridyl, pyrazinyl, pyrimidyl, furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl, benzofuranyl and benzothiazol. Suitable heteroalicyclic substituent groups of compounds of the invention contain one or more N, O or S atoms and include, e.g., tetrahydrofuranyl, tetrahydropyranyl, piperidinyl, morpholino and pyrrolindinyl groups. Suitable carbocyclic aryl groups of compounds of the invention include single and multiple ring compounds, including multiple ring compounds that contain separate and/or fused aryl groups. Typical carbocyclic aryl groups contain 1 to 3 separate or fused rings and from 6 to about 18 carbon ring atoms. Specifically preferred carbocyclic aryl groups include phenyl including substituted phenyl, such as 2-substituted phenyl, 3-substituted phenyl, 4-substituted phenyl or 2,3-substituted, 2,4-substituted phenyl, including where such phenyl substituents are selected from the same group as defined above in Formula I for the substituent X; naphthyl including 1-naphthyl and 2-naphthyl; biphenyl; phenanthryl; and anthracyl. As mentioned above, substituted and unsubstituted carbocyclic aryl, particularly substituted and unsubstituted naphthyl and phenyl, are preferred X, W and Y groups of compounds of the invention. Suitable aralkyl groups of compounds of the invention include single and multiple ring compounds, including multiple ring compounds that contain separate and/or fused aryl groups. Typical aralkyl groups contain 1 to 3 separate or fused rings and from 6 to about 18 carbon ring atoms. Preferred aralkyl groups include benzyl and —CH2-naphthyl. References herein to substituted X, W, Y, R, R1 and R2 groups of compounds of the invention refer to the specified moiety that may be substituted at one or more available positions by one or more suitable groups such as, e.g., halogen such as fluoro, chloro, bromo and iodo; cyano; hydroxyl; nitro; azido; alkanoyl such as a C1-6alkanoyl group such as acyl and the like; carboxamido; alkyl groups including those groups having 1 to about 12 carbon atoms or from 1 to about 6 carbon atoms and more preferably 1-3 carbon atoms; alkenyl and alkynyl groups including groups having one or more unsaturated linkages and from 2 to about 12 carbon or from 2 to about 6 carbon atoms; alkylsilyl groups such as those groups having from 1 to about 12 carbons, or more preferably 1 to about 6 carbons and 1 or Si groups; alkoxy groups including those having one or more oxygen linkages and from 1 to about 12 carbon atoms or 1 to about 6 carbon atoms; aryloxy such as phenoxy; alkylthio groups including those moieties having one or more thioether linkages and from 1 to about 12 carbon atoms or from 1 to about 6 carbon atoms; alkylsulfinyl groups including those moieties having one or more sulfinyl linkages and from 1 to about 12 carbon atoms or from 1 to about 6 carbon atoms; alkylsulfonyl groups including those moieties having one or more sulfonyl linkages and from 1 to about 12 carbon atoms or from 1 to about 6 carbon atoms; alkylamino groups such as groups having one or more N atoms and from 1 to about 12 carbon atoms or from 1 to about 6 carbon atoms; carbocyclic aryl having 6 or more carbons, particularly phenyl; and aralkyl having from about 7 to 14 carbon atoms such as benzyl; and heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms. It should be understood that alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl and aminoalkyl substituent groups described above include groups where a hetero atom is directly bonded to a ring system, such as a carbocyclic aryl group or a heterocyclic group, as well as groups where a hetero atom of the group is spaced from such ring system by an alkylene linkage, e.g. of 1 to about 4 carbon atoms. Specifically preferred compounds of the invention include the following: N-carboximidamide-r-2, c-6-di(4-methylphenyl)piperidine; N-carboximidamide-r-2, c-6-di(4-isopropylphenyl)piperidine; N-carboximidamide-r-2, t-6-di(4-methylphenyl)piperidine; N-carboximidamide-r-2, c-6-diphenylpyrrolidine; N-(N′-phenyl)carboximidamide-r-2, c-6-diphenylpiperidine; and pharmaceutically acceptable salts thereof. See General of Organic Chemistry, vol. 56, 4833-4840 (1991) for discussion of the nomenclature of these preferred compounds. The structural formulae of these preferred compounds are also shown in the examples which follow. Compounds of the invention can be prepared by several routes. For example, compounds of the invention can be prepared by reaction of cyanamide with a precursor derivative of Formula I that does not contain the N-substituent of —C(═NH)NH2 or —C(═NR2)NRR1, i.e. a compound of the following Formula III (where Z, X, m, n and p are each the same as defined above for Formula I): More particularly, compounds of the invention can be suitably prepared by reaction of a precursor compound of Formula III above with cyanamide to provide compounds of Formula I, or a substituted cyanamide to provide compounds of Formula II, in a suitable solvent such as methanol, ethanol and chloroform or the like under an inert atmosphere such as argon or nitrogen. Typically, an HCl or other acid addition salt of the precursor compound III is reacted with the cyanamide. The reaction solution is suitably heated e.g. from about 100° C. or greater for 2 to about 60 hours until reaction completion, e.g. as indicated by thin layer chromatography. The reaction solution is then cooled to room temperature, and the solvent is then removed under reduced pressure to provide the desired compound of the invention. The crude product then can be purified by recrystallization and/or column chromatography, e.g. by elution one or more times on silica gel (e.g., 60-200 mesh, 50× w/w) with suitable solvents. See Example 1, Part II which follows for exemplary conditions. Precursor compounds of the above Formula III may be commercially available or can be prepared by reduction of the corresponding unsaturated heterocyclic nitrogen compound, e.g. by use of a reducing agent such as sodium and ethanol. See Example 1, Part 1 for exemplary conditions of such reduction. Hydrogenation also may be employed using palladium or other suitable catalyst. See Example 4, Part III. The nitrogen may be suitably activated during hydrogenation, e.g. with an oxycarbonyl group such as t-butoxycarbonyl or the like, which group can be then removed such as by acidic hydrolysis -prior to reaction with cyanamide or other reagent. See Example 4 which follows for an exemplary procedure. Substituted unsaturated cyclic amine compounds to employ in such reduction reactions can be prepared by several methods. For example, an organometallic reagent can be prepared (typically Group I or II metal, particularly Li or Mg) such as by a halogen-metal exchange reaction followed by reaction of that organometallic reagent with a halopyridine or other halogen-substituted cyclic amine. See Example 2, Part 1, Method A for an exemplary procedure. Alternatively, a substituted pyridine or other unsaturated precursor compound can be prepared by cyclization of an intermediate compound that contains the ring substituents (i.e. groups X, W and Y in the above formulae), e.g. by cyclization of a substituted 1,5-diketopentyl compound with hydroxylamine. See Example 2, Method B which follows for exemplary conditions. Compounds of Formulae I and II also may be prepared by reaction of a precursor compound of Formula III above with cyanogen bromide to provide the N-cyano derivative (i.e. compounds of Formula III above substituted at the depicted ring nitrogen by cyano). That cyano intermediate then may be suitably reacted an amine, particularly an ammonium salt such as an acetate salt, typically with heating to provide the N-imine substituted compound of Formula I. See Example 3 which follows for exemplary conditions. Compounds of Formula II may be prepared by reaction of the N-cyano derivative with a primary or secondary amine (to provide the desired R and R1 groups as defined above for Formula II) in the presence of a Lewis acid such as AlCl3 and the like. See Example 5 which follows for an exemplary synthesis. Alkylsulfinyl-substituted or alkylsulfonyl-substituted reagents, that can provide correspondingly substituted compounds of the invention as described above, can be provided by oxidation (e.g., H2O2) of alkylthio-substituted reagents. As discussed above, chiral compounds of the invention may be used as optically enriched or racemic mixtures. An optically enriched mixture contains substantially more (e.g. about 60%, 70%, 80% or 90% or more) of one enantiomer or diastereoisomer than the other stereoisomer(s). Optically enriched mixtures can be obtained by known procedures, e.g., column chromatography using an optically active binding material or formation of a salt using an optically active material, particularly an optically active acid. As discussed above, the present invention includes methods for treating or preventing certain neurological disorders, including the consequences of stroke, heart attack and traumatic head or brain injury, epilepsy or neurodegenerative diseases comprising the administration of an effective amount of one or more compounds of the invention to a subject including a mammal, particularly a human, in need of such treatment. In particular, the invention provides methods for treatment and/or prophylaxis of nerve cell death (degeneration) resulting e.g. from hypoxia, hypoglycemia, brain or spinal cord ischemia, brain or spinal cord trauma, stroke, heart attack or drowning. Typical candidates for treatment include e.g. heart attack, stroke and/or persons suffering from cardiac arrest neurological deficits, brain or spinal cord injury patients, patients undergoing major surgery such as heart surgery where brain ischemia is a potential complication and patients such as divers suffering from decompression sickness due to gas emboli in the blood stream. Candidates for treatment also will include those patients undergoing a surgical procedure involving extra-corporal circulation such as e.g. a bypass procedure. The invention in particular provides methods for treatment which comprise administration of one or more compounds of the invention to a patient that is undergoing surgery or other procedure where brain or spinal cord ischemia is a potential risk. For example, carotid endarterectomy is a surgical procedure employed to correct atherosclerosis of the carotid arteries. Major risks associated with the procedure include intraoperative embolization and the danger of hypertension in the brain following increased cerebral blood flow, which may result in aneurism or hemorrhage. Thus, an effective amount of one or more compounds of the present invention could be administered pre-operatively or peri-operatively to reduce such risks associated with carotid endarterectomy, or other post-surgical neurological deficits. The invention further includes methods for prophylaxis against neurological deficits resulting from e.g. coronary artery bypass graft surgery and aortic valve replacement surgery, or other procedure involving extra-corporal circulation. Those methods will comprise administering to a patient undergoing such surgical procedures an effective amount of one or more compounds of the invention, typically either pre-operatively or peri-operatively. The invention also provides methods for prophylaxis and treatment against neurological injury for patients undergoing myocardial infarction, a procedure that can result in ischemic insult to the patient. Such methods will comprise administering to a patient undergoing such surgical procedure an effective amount of one or more compounds of the invention, typically either pre-operatively or peri-operatively. Also provided are methods for treating or preventing neuropathic pain such as may experienced by cancer patients, persons having diabetes, amputees and other persons who may experience neuropathic pain. These methods for treatment comprise administration of an effective amount of one or more compounds of the invention to a patient in need of such treatment. The invention also provides methods for treatment and prophylaxis against eye disorders and injury, including methods for treatment of reduced flow of blood or other nutrients to retinal tissue or optic nerve, methods for treatment of retinal ischemia and trauma and associated disorders, and methods for treatment of optic nerve damage/injury. Disorders associated with retinal or optic nerve injury or ischemia that may be treated in accordance with the invention include e.g. diabetes, significantly elevated intraocular pressures and glaucoma, diseases such as retinal artery or vein occlusion, atherosclerosis, venous capillary insufficiency, senile macular degeneration and cystoid macular edema. In such methods, a compound of the invention can be administered parenterally or by other procedure as described herein to a subject a suffering from or susceptible to ischemic insult or other injury or disorder that may adversely affect visual function. Post-ischemic or post-injury administration also may limit retinal damage. Intravitreal injection of a compound of the invention also may be a preferred administration route to provide more direct treatment to the injured retina or optic nerve. The invention also provides methods for treatment of a subject suffering from shingles as well as treatment of a person suffering from or susceptible to migraines, particularly to alleviate the pain and discomfort associated with those disorders. These methods comprise administration of an effective amount of one or more compounds of the invention to a patient in need of treatment. The invention further provides a method of treating Korsakoff's disease, a chronic alcoholism-induced condition, comprising administering to a subject including a mammal, particularly a human, one or more compounds of the invention in an amount effective to treat the disease. Compounds of the invention are anticipated to have utility for the attenuation of cell loss, hemorrhages and/or amino acid changes associated with Korsakoff's disease. As discussed above, the invention also includes methods for treating a person suffering from or susceptible to cerebral palsy, emesis, narcotic withdrawal symptoms and age-dependent dementia, comprising administering to a subject including a mammal, particularly a human, one or more compounds of the invention in an amount effective to treat the condition. As discussed above, preferred compounds of the invention are active in a standard anticonvulsant in vivo audiogenic test, such as the audiogenic mouse assay of Example 6 which follows, where DBA/2 mice about 20-23 days old are injected intraperitoneally with a test compound 30 minutes prior to being placed in a bell jar with exposure to auditory stimulus of 12 KHz sine wave at 110-120 db. References herein in vivo “audiogenic assay” are intended to refer to that protocol. Generally preferred compounds exhibit 20% or more inhibition (relative to subjects treated with vehicle control only) at a dose of 20 mg/kg, more preferably about 50% or more or 70% or more inhibition at a dose of 20 mg/kg in such an in vivo audiogenic assay. As discussed above, activity in the audiogenic assay has been recognized as indicative that a test compound has neuroprotective properties. See, e.g., M. Tricklebank et al., European Journal of Pharmacology, supra; T. Seyfried, Federation Proceedings, supra. The invention also provides methods for determining binding activity of compounds of the invention as well as in vitro and in vivo binding activity diagnostic methods using one or more radiolabelled compounds of the invention, e.g., a compound of the invention that is labeled with 125I, tritium, 32P, 99Tc, or the like, preferably 125I. For instance, a compound of the invention having a phenyl or other aryl substituent that is ring substituted with one or more 125I groups can be administered to a mammal and the subject then scanned for binding of the compound. Specifically, single photon emission computed tomography (“SPECT”) can be employed to detect such binding. Such an analysis of the mammal could e.g. aid in the diagnosis and treatment of acute cerebral ischemia. That is, a labeled compound of the invention will selectively bind to ischemic tissue of e.g. a subject's brain to differentiate between ischemic and non-ischemic tissue and thereby assess trauma or other injury to the brain. Accordingly, the invention includes compounds of the invention that contain a radiolabel such as 125I, tritium, 32P, 99Tc, or the like, preferably 125I. Such radiolabelled compounds can be suitably prepared by procedures known in the synthesis art. For example, a compound of the invention having an aromatic group, such as phenyl, that has a bromo or chloro ring substituent can be employed in an exchange labeling reaction to provide the corresponding compound having an 125I ring substituent. Compounds of the invention may be used in therapy in conjunction with other medicaments. For example, for treatment of a stroke victim or a person susceptible to stroke, one or more compounds of the invention may be suitably administered together with a pharmaceutical targeted for interaction in the blood clotting mechanism such as streptokinase, tPA, urokinase and other agents that lyse clots. Also, one or more compounds of the invention may be administered together with agents such as heparin and related heparin-based compounds, acenocoumarol or other known anticoagulants. Compounds of the invention also may function as prodrugs and may be metabolized in vivo to forms of enhanced activity. The compounds of this invention can be administered intranasally, orally or by injection, e.g., intramuscular, intraperitoneal, subcutaneous or intravenous injection, or by transdermal, intraocular or enteral means. The optimal dose can be determined by conventional means. Compounds of the present invention are suitably administered to a subject in the protonated and water-soluble form, e.g., as a pharmaceutically acceptable salt of an organic or inorganic acid, e.g., hydrochloride, sulfate, hemi-sulfate, phosphate, nitrate, acetate, oxalate, citrate, maleate, mesylate, etc. Compounds of the invention can be employed, either alone or in combination with one or more other therapeutic agents as discussed above, as a pharmaceutical composition in mixture with conventional excipient, i.e., pharmaceutically acceptable organic or inorganic carrier substances suitable for parenteral, enteral or intranasal application which do not deleteriously react with the active compounds and are not deleterious to the recipient thereof. Suitable pharmaceutically acceptable carriers include but are not limited to water, salt solutions, alcohol, vegetable oils, polyethylene glycols, gelatin, lactose, amylose, magnesium stearate, talc, silicic acid, viscous paraffin, perfume oil, fatty acid monoglycerides and diglycerides, petroethral fatty acid esters, hydroxymethyl-cellulose, polyvinylpyrrolidone, etc. The pharmaceutical preparations can be sterilized and if desired mixed with auxiliary agents, e.g., lubricants, preservatives, stabilizers, wetting agents, emulsifiers, salts for influencing osmotic pressure, buffers, colorings, flavorings and/or aromatic substances and the like which do not deleteriously react with the active compounds. For parenteral application, particularly suitable are solutions, preferably oily or aqueous solutions as well as suspensions, emulsions, or implants, including suppositories. Ampules are convenient unit dosages. For enteral application, particularly suitable are tablets, dragees or capsules having talc and/or carbohydrate carrier binder or the like, the carrier preferably being lactose and/or corn starch and/or potato starch. A syrup, elixir or the like can be used wherein a sweetened vehicle is employed. Sustained release compositions can be formulated including those wherein the active component is protected with differentially degradable coatings, e.g., by microencapsulation, multiple coatings, etc. Intravenous or parenteral administration, e.g., sub-cutaneous, intraperitoneal or intramuscular administration are preferred. The compounds of this invention are particularly valuable in the treatment of mammalian subjects, e.g., humans, to provide neuroprotective therapy and/or prophylaxis. Typically, such subjects include those afflicted with neurodegenerative diseases such as Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Alzheimer's disease, Down's Syndrome and Korsakoff's disease. Also suitable for treatment are those subjects suffering from or likely to suffer from nervous system dysfunctions resulting from, for example, epilepsy or nerve cell degeneration which is the result of hypoxia, hypoglycemia, brain or spinal chord ischemia or brain or spinal chord trauma. As discussed above, typical candidates for treatment include heart attack, stroke, brain or spinal cord injury patients, patients undergoing major surgery where brain or spinal cord ischemia is a potential complication and patients such as divers suffering from decompression sickness due to gas emboli in the blood stream. It will be appreciated that the actual preferred amounts of active compounds used in a given therapy will vary according to the specific compound being utilized, the particular compositions formulated, the mode of application, the particular site of administration, etc. Optimal administration rates for a given protocol of administration can be readily ascertained by those skilled in the art using conventional dosage determination tests conducted with regard to the foregoing guidelines. In general, a suitable effective dose of one or more compounds of the invention particularly when using the more potent compound(s) of the invention, will be in the range of from 0.01 to 100 milligrams per kilogram of bodyweight of recipient per day, preferably in the range of from 0.01 to 20 milligrams per kilogram bodyweight of recipient per day, more preferably in the range of 0.05 to 4 milligrams per kilogram bodyweight of recipient per day. The desired dose is suitably administered once daily, or several sub-doses, e.g. 2 to 4 sub-doses, are administered at appropriate intervals through the day, or other appropriate schedule. Such sub-doses may be administered as unit dosage forms, e.g., containing from 0.05 to 10 milligrams of compound(s) of the invention, per unit dosage, preferably from 0.2 to 2 milligrams per unit dosage. Compounds of the invention also can be useful as rubber accelerators. See U.S. Pat. No. 1,411,713 for a discussion of rubber accelerator applications. The entire text of all documents cited herein are incorporated by reference herein. The following non-limiting examples are illustrative of the invention. General Comments In the following examples, all percentages reported herein, unless otherwise specified, are percent by weight. All temperatures are expressed in degrees Celsius. Melting points were determined in open capillary tubes on a Thomas-Hoover apparatus and are uncorrected. Thin-layer chromatography was performed on Baker-flex 1B2-F silica gel plates. Compounds were visualized on TLC with 254-nM UV light or as a blue spot with bromcresol spray reagent (Sigma Chemical Co.). Preparative TLC was performed on Analtech GF precoated silica gel (1000 μm) glass-backed plates (20×20 cm). NMR spectra were recorded on Varian Gemini 300 and the chemical shifts were reported in ppm (δ) relative to the residual signal of the deuterated solvent (CDCl3, δ 7.26; CHD2OD, δ 3.30). Elemental analyses were performed by either Galbraith Laboratories (Knoxville, Tenn.) or MHW Laboratories (Tuscon, Ariz.). High Resolution Mass spectra (HRMS) were recorded on a Finnegan MAT 90. HPLC were performed on a C18 reverse phase column using 50:50 water:acetonitrile with 0.1% TFA as a mobile phase. Chlorobenzene, ether (Et2O) and tetrahydrofuran (THF) were anhydrous quality solvents (Sure Seal) supplied by Aldrich. All other solvents were reagent grade. EXAMPLE 1 Preparation of N-carboximidamide-r-2, c-6-di(4-methylphenyl)piperidine, mesylate (includes Parts I and II) Part I: Preparation of r-2, c-6-di(4-methylphenyl)piperidine, hydrochloride and (±)r-2,t-6-di(4-methylphenyl)piperidine, hydrochloride To a solution of 2,6-di-p-tolylpyridine (3.0 g, 11.6 mmol) in 30 ml of absolute ethanol was added sodium (6.0 g, 0.26 mol) in small pieces and the reaction was kept at gentle reflux. After the addition of sodium was completed, 10 ml of ethanol was added and the reaction mixture was heated to reflux until the sodium had disappeared. The solution was cooled to room temperature and 50 ml of water were added dropwise. Ethanol was evaporated from the reaction mixture, the aqueous phase was extracted several times with diethyl ether and the combined etherates were washed with water, brine and dried over MgSO4. The drying agent was removed by filtration and the etherate was concentrated to yield a crude product which was purified on silica gel column with hexane/ethyl acetate as eluant (20/1 to 10/1) to afford r-2, c-6-di(4-methylphenyl)piperidine and r-2, t-6-di(4-methylphenyl)piperidine. To form the HCl salt, r-2, c-6-di(4-methylphenyl)piperidine was dissolved in a minimum amount of diethyl ether and 5 ml of 1N HCl (5 mmol) diethyl ether solution was added. The precipitate was collected by filtration, washed with diethyl ether and dried to afford r-2, c-6-di(4-methylphenyl)piperidine, HCl (1.35 g, 38.7%). r-2, c-6-Di(4-methylphenyl)piperidine was converted to the HCl salt by the same method as r-2, c-6-di(4-methylphenyl)piperidine to afford r-2, t-6-di(4-methylphenyl)piperidine, HCl (1.28 g, 33.8%). r-2, c-6-Di(4-methylphenyl)piperidine, HCl: a white solid; purity 95.9% (HPLC); Mass: 265(m/c); mp:315-317° C.; TLC: Rf=0.32 (hexane/ethylacetate 10/1); 1H-NMR (CD3OD):δ ppm 7.42 (d, ArH, 4H) 7.26 (d, ArH, 4H), 4.42 (t, ArCH, 2H), 2.35 (s,CH3, 6H), 1.85-2.20 (m, CH2, 6H); Anal. (C, H, N; C19H23N, HCl): cal. (%):C 75.60, H 8.01, N 4.64; found(%): C 75.43, H 8.05, N 4.65. r-2,t-6-Di(4-methylphenyl)piperidine, HCl: a white solid purity 98.2% (HPLC); Mass: 265 (m/e); mp: 279-281° C.; TLC: Rf=0.15 (hexane/ethylacelate 10/1); 1H-NMR (CD3OD): δ ppm 7.39 (d, ArH, 4H), 7.32 (d, ArH, 4H), 4.54 (t, ArCH, 2H), 2.38 (s, CH3, 6H), 1.90-2.40 (m, CH2,6H); Anal. (C, H, N: C19H23N, HCl): cal.(%): C 75.60, H 8.01, N 4.64; found (%): C 75.82, H 7.85, N 4.80. Part II: Preparation of N-carboximidamide-r-2, c-6-di(4-methyphenyl)piperidine, mesylate Cyanamide (1.50 g, 35.7 mmol) and r-2, c-6-di(4-methylphenyl)piperidine hydrochloride (0.50 g, 1.66 mmol) were dissolved in 20 ml of methanol and the reaction mixture was refluxed for 48 hours. The solution was concentrated to afford a crude product which was purified on silica gel column with chloroform/methanol (20/1) as eluant. The product was collected, concentrated and dissolved in 100 ml of 1N NaOH. The solution was extracted with chloroform, the organic phase was washed with 1N NaOH, water, brine and dried over MgSO4. After filtration and evaporation to dryness, the light-yellow solid obtained was dissolved in diethyl ether. To this solution was added sulfonic acid (70 mg, 0.72 mmol). The precipitate obtained was collected by filtration, washed with diethyl ether and dried under vacuum (0.256 g, 48.2%). A white solid; purity: 86.4% (HPLC); HRMS: 307.2048 (Cal.:307.2033 for C20H25N3); mp: 183-185° C.; TLC: Rf=0.43 (SiO2, CHCl3/MeOH=10/1). 1H-NMR (CD3OD): δ ppm 7.25 (d, ArH, 4H), 7.15 (d, ArH, 4H), 4.93 (t, ArCH, 2H), 2.69 (s, CH3SO3H, 3H), 2.30 (s, CH3, 6H), 1.80-2.30 (m, CH2, 6H). EXAMPLE 2 Preparation of N-carboximidamide-r-2,c-6-di(4-isopropylphenyl)piperidine, hydrochloride (includes Parts I, II and III; Part I carried out with alternative Methods A and B) Part I: Preparation of 2,6-di(4-isopropylphenyl)pyridine Method A To a solution of 4-bromoisopropylbenzene (3.0 g, 14.8 mmol) in 10 ml of diethyl ether was added dropwise under argon, at −78° C., n-butyllithium 2.5M in hexanes (5.91 ml, 14.8 mmol) and then the reaction mixture was warmed to −10 to 0° C. 2,6-Difluoropyridine (0.858 g, 7.39 mmol) was added dropwise over one hour period. After stirring for 30 minutes, the reaction mixture was warmed up to room temperature and stirred for 16 hours. The reaction was quenched with a 20% ammonium chloride solution, the organic phase was separated and the aqueous phase was extracted with diethyl ether. The combined etherates were dried over MgSO4, and filtration and concentration afforded a crude product which was purified on silica gel column with chloroform as eluant. The product was collected, concentrated and dried to yield the title compound (0.87 g, 37.4%). 1H-HMR(CDCl3); δ ppm 8.08 (d, ArH, 4H), 7.80 (t, ArH, 1H), 7.65 (d, ArH, 2H), 7.36 (d, ArH, 4H), 3.00 (m, CH, 2H), 1.30(d, CH3, J=6.93 Hz, 12H). Method B Part 1: Preparation of 1,3,-di(4′-isopropylbenzoyl)propane To a solution of cumene (5.00 g, 41.2 mmol) in methylene chloride (80 ml) was added AlCl3 (5.49 g, 41.2 mmol) under argon at 0 to 5° C. Glutaryl chloride (3.58 g, 20.0 mmol) in methylene chloride (30 ml) was added and the mixture was warmed to room temperature and stirred for 12 hours. The reaction was then poured into 100 ml of ice water and the organic phase separated. The aqueous phase was extracted several times with chloroform. The combined organic phases were washed with water, NaOH 1N, brine and dried over MgSO4. Filtration and evaporation to dryness afforded a crude product which was purified on silica gel column with chloroform. The product was collected, concentrated and dried (4.55 g, 68%). 1H-NMR (CDCl3): δ ppm 7.92 (d, ArH, 4H), 7.31 (d, ArH, 4H), 3.09 (t, CH2, J=7.0 Hz, 4H), 2.98 (m, CH, 2H), 2.19 (m, CH2, 2H), 1.26 (d, CH3, J=6.93, 12H). Part 2: Preparation of 2,6-di(4-isopropylphenyl)pyridine 1,3-Di(4′-isopropylbenzoyl) propane (1.85 g, 5.50 mmol) and hydroxylamine hydrochloride (0.414 g, 5.89 mmol) were dissolved in glacial acetic acid (7 ml). After 24 hours of reflux, the reaction mixture was cooled down to room temperature and concentrated to afford a brown oil to which was added 100 ml of water. To this solution was added 1N NaOH until pH=13. The aqueous phase was extracted several times with chloroform. The combined organic phases were washed with 1N NaOH, water, brine and dried over MgSO4. Filtration and evaporation to dryness afforded a crude product which was purified on silica gel column with hexane/ethyl acetate (20:1) as eluant. The product was collected, concentrated and dried (0.521 g, 30%). 1H-NMR (CDCl3) for the product corresponded to that set forth above under Example 2 Part I, Method A. Part II: Preparation of r-2, c-6-di(4-isopropylphenyl)piperidine, hydrochloride This compound was prepared by the method set forth in Example 1, Part 1 above with use of 2,6-di(4-isopropylphenyl)pyridine) in place of 2,6-di-p-tolylpyridine. 1H-NMR(CD3OD): δ ppm 7.49 (d, ArH, 4H), 7.35 (d, ArH, 4H), 4.45 (t, ArCH, 2H), 2.92 (m, CH, 2H), 2.15 (m, CH2, 6H), 1.35(d, CH3, J=6.93 Hz, 12H). Part III: Preparation of N-carboximidamide-r-2, c-6-di(4-isopropylphenyl)piperidine, hydrochloride This compound was prepared by the method set forth in Example I Part II above with use of r-2, c-6-di(4-isopropylphenyl)piperidine, hydrochloride in place of r-2, c-6-di(4-methylphenyl)piperidine. r-2,c-6-Di(4-isopropylphenyl)piperidine, HCl: a white solid; purity 99.7% (HPLC); Mass: 364 MH+; mp: 197-199° C.; TLC: Rf=0.29 (SiO2,CHCl3/MeOH=10/1); 1H-NMR (CD3OD): δ ppm 7.27 (d, ArH, 4H), 7.18 (d, ArH, 4H), 4.97 (m, ArCH, 2H), 2.85 (m, CH, 2H), 1.80-2.30 (m, CH2, 6H), 1.21 (d, CH3 J=6.93 Hz, 12H); Anal. (C,H,N; C24H33N3, HCl): cal.(%): C 72.06, H 8.57, N 10.50; found (%): C 72.18, H 8.49, N 10.59. EXAMPLE 3 Preparation of (±) N-carboximidamide-r-2, t-6-di(4-methylphenyl) piperidine, hydrochloride (Parts I, II and III) Part I: Preparation of (±)2,6-di(4-methylphenyl)piperidine This compound was prepared by the method indicated above in Example 1, Part 1 and omitting the HCl treatment. Part II: Preparation of (±)N-cyano-r-2,t-6-di(4-methylphenyl)piperidine (±)r-2, t-6-(4-Methyl)phenylpiperidine (365 mg, 1.37 mmol) was suspended in 30 ml of an ice-bath cooled mixture of methanol-water 2:1. Ammonium acetate (170 mg, 2.05 mmol) and cyanogen bromide (220 mg, 2.05 mmol) were added successively. After two hours of stirring, the water bath was removed and the suspension stirred overnight. The white flaky precipitate obtained was collected on a glass filter and washed with water: yield 215 mg (54%); 1H-NMR(CDCl3): δ ppm 7.34 (d, ArH, 4H), 7.23 (d, ArH, 4H), 4.48 (dd, ArCH, J=4.3, 7.0 Hz, 2H), 2.36 (s, CH3, 6H), 2.20 (m, CH2, 2H), 2.05 (m, CH2, 2H), 1.78 (m, CH2, 2H); purity 89% (HPLC); TLC: Rf=0.3 (hexane-ethylacetate 2/0.5); Mass (CI—NH3): 308 (M+NH4)+, 291(MH)+. Part III: Preparation of (±) N-Carboximidamide-r-2, t-6-di(4-methylphenyl)piperidine, hydrochloride (±) N-cyano-r-2, t-6(4-methyl)phenylpiperidine (215 mg, 0.75 mmol) was mixed with an excess of ammonium acetate (1.5 g) and the paste obtained was heated to the melting point at 120° C. to obtain a clear solution. After 13 hours of heating, the solution was cooled down and water was added. This solution was kept in the freezer until precipitation occurred (12 hours). The precipitate was filtered off and the filtrate basified with sodium hydroxide 1N. The filtrate was extracted with diethyl-ether, washed with water and acidified with HCl 1N to precipitate (±) N-carboximidamide-r-2, t-6-di(4-methylphenyl) piperidine, HCl as a white solid: yield 60 mg (28%), 1H-NMR (CD3OD): δ ppm 7.4 (d, ArH, 4H), 7.3 (d, ArH, 4H), 4.55 (dd, 2ArCH, 2H), 2.4 (s, CH3, 6H), 2.35 (m, CH2, 2H), 2.15 (m, CH2, 2H), 1.95 (m, CH2, 2H), Mass: MH+(308), MH—CN2H2 (266); purity: 98.9% (HPLC); TLC: Rf=0.3 (chloroform/methanol 10/0.5). EXAMPLE 4 Preparation of N-carboximidamide-r-2,c-6-diphenylpyrrolidine, hydrochloride (includes Parts I, II, III, IV and V) Part I: Preparation of 2,6-diphenylpyrrole Dibenzoylethane (1.50 g, 6.30 mmol) and ammonium acetate (2.00 g, 25.2 mmol) were mixed together and the mixture was heated to 100° C. for 4 hours. The reaction mixture was cooled down to room temperature, diluted with 30 ml of water and basified with 1N NaOH until pH 14. The reaction mixture was extracted several times with chloroform. The combined organic phases were washed with 1N NaOH, water, brine and dried over MgSO4. Filtration and concentration afforded a crude product which was purified on silica gel column with hexanes/ethyl acetate (10/1) as eluant, the product was collected to yield after evaporation to dryness 0.90 g (65.2%). A light yellow solid; 1H-NMR (CDCl3): δ ppm 7.20-7.60 (m, ArH, 10H), 6.6 (d,ArH, 2H). Part II: Preparation of N-Boc-2-6-diphenylpyrrole 4-Dimethylaminopyridine (DMAP) (5.4 mg, 0.046 mmol) and di-tert-butyldicarbonate (100 mg. 0.456 mmol) were added to a solution of 2,6-diphenylpyrrole (100 mg, 0.456 mmol) in dry acetonitrile (5 ml) under argon. The reaction mixture was refluxed for 5 hours. The crude product was purified on silica gel column with hexanes/ethyl acetate (10/1) as eluant. The product was collected, concentrated and dried to afford the title compound, N-t-butyloxycarbonyl-2,6-diphenylpyrrole as an oil (126 mg, 86.6%). 1H-NMR (CDCl3): δ ppm 7.25-7.55 (m, ArH, 10H), 6.6 (d, ArH, 2H), 1.17 (s, CH3, 9H). Part III: Preparation of N-Boc-2-6-diphenylpyrrolidine To a solution of N-Boc-2,6-diphenylpyrrole (1.027 g, 3.22 mmol) in methanol (80 ml) was added palladium (5%) on activated carbon (0.250 g). The reaction mixture was hydrogenated (10 psi) for 1.5 hours. Filtration and evaporation to dryness afforded N-Boc-2,6-diphenylpyrrolidine (1.01 g, 97%). 1H-NMR (CDCl3): δ ppm 7.20-7.60 (m, ArH, 10H), 5.0 (m, ArCH, 2H), 2.45 (m, CH2, 2H), 1.17 (s, CH3, 9H). Part IV: Preparation of 2,6-diphenylpyrrolidine, hydrochloride Trifluoroacetic acid (10 ml) was added to 2,6-diphenylpyrrolidine (1.01 g, 3.13 mmol) at 0° C. The mixture was stirred at 0° C. for 10 minutes, then the solvent was evaporated to afford a light brown solid to which was added 100 ml of water. To this solution was added 1N NaOH until pH=14 and the aqueous phase was extracted with chloroform. The organic phase was washed with 1N NaOH, water, brine and dried over MgSO4. After filtration and evaporation to dryness, the light-yellow solid obtained was dissolved in diethyl-ether. To this solution was added 1N HCl (5 ml, 5 mmol), the precipitate obtained was collected by filtration, washed with diethyl-ether and dried under vacuum (0.590 g, 72.7%). 1N-NMR (CDCl3): δ ppm 7.30-7.60 (m, ArH, 10H), 4.95 (m,ArCH,2H), 2.45-2.70 (m, CH2, 4H). Part V: Preparation of N-carboximidamide-r-2, c-6-diphenylpyrrolidine hydrochloride Cyanamide (1.40 g. 33.3 mmol) and r-2, c-6-diphenylpyrrolidine (0.50 g, 1.92 mmol) were dissolved in 10 ml of methanol. The reaction mixture was refluxed for 24 hours. The solution was concentrated to afford a crude product which was purified on silica gel column with chloroform/methanol (24/1). The products were collected, concentrated and dissolved in 100 ml of 1N NaOH. The solution was extracted with chloroform. The organic phase was washed with 1N NaOH, water, brine and dried over MgSO4. Filtration and evaporation to dryness gave a fluffy solid which was dissolved in 3 ml of chloroform. To this solution was added 3 ml of 1N HCl in diethyl ether (3 mmol). The precipitate was collected by filtration and washed with diethyl ether and dried under vacuum (0.210 g, 36.2%); a white solid; purity: 99.5% (HPLC); Mass: 266 MH+; mp: 242-244° C.; TLC: Rf=0.23 (SiO2 CHCl3/MeOH=10/1); 1H-NMR (CD3OD): δ ppm 7.45-7.55 (m, ArH, 10H), 5.17 (t, ArCH, 2H), 2.58 (m, CH2,2H), 2.10 (m, CH2, 2H); Anal. (C, H, N; C17H19N3, HCl, 0.7H2O): cal.(%): C 64.97, H 6.81, N 13.38; found (%): C 64.59, H 6.39, N 13.43. EXAMPLE 5 Preparation of N-(N′-phenylcarboximidamide)-r-2,c-6-diphenylpiperidine, hydrochloride (includes Parts I, II and III) Part I: Preparation of 2,6-diphenylpiperidine, hydrochloride This compound was prepared as described in Example 1, Part I. 1H-NMR (CDCl3): δ ppm 7.20-7.50 (m, ArH, 10H), 3.82 (d, ArCH, 2H), 1.45-2.05 (m, CH2,6H). Part II: Preparation of N-cyano-r-2, c-6-diphenylpiperidine This compound was prepared as described in Example 3, Part II above. 1H-NMR (CDCl3): δ ppm 7.30-7.50 (m, ArH, 10H), 4.18(d, ArCH, 2H), 1.60-2.10(m, CH2, 6H). Part III: Preparation of N-(N′-phenylcarboximidamide)-r-2,c-6-diphenyl piperidine, hydrochloride To a solution of N-cyano-r-2-6-diphenylpiperidine (200 mg. 0,76 mmol) in chlorobenzene (5 ml) was added AlCl3 (100 mg, 0.76 mmol) and the suspension was stirred for 5 minutes. Aniline hydrochloride (100 mg, 0.76 mmol) was added, and the reaction mixture was heated to 120° C. for 4 hours. The reaction mixture was purified on silica gel column with chloroform/methanol (20/1). The fractions containing the product were evaporated to dryness to yield 0.127 g (42.5%). A white fluffy solid; purity 92.3% (HPLC); Mass: 356 MH+; mp: 82-84° C.; TLC: Rf=0.37 (SiO2, CHCl3/MeOH=20/1); 1H-NMR (CD3OD): δ ppm 7.10-7.50 (m, ArH, 15H), 4.76 (t, ArCH, J=7.26 Hz, 2H), 2.00-2.40 (m, CH2, 6H); Anal. (C, H, N; C24H25N3, HCl): cal. (%): C 73.55, H 6.69, N 10.72; found (%) C 73.63, H 6.52, N 10.88. EXAMPLE 6 In vivo Anticonvulsant Activity in the DBA/2 Mouse Model (Mouse Audiogenic Assay) The in vivo potency of compounds of the invention is exemplified by data summarized in the Table I below and obtained pursuant to the following protocol. Compounds were tested for their effectiveness in preventing seizures in DBA/2 mice which have a unique sensitivity to auditory stimulation. Exposure to loud high-frequency sounds can trigger seizure activity in these animals. This sensitivity develops from postnatal day 12 and peaks around day 21 and slowly diminishes as the animals mature. The unusual response to auditory stimulation in this strain of mouse is believed to be due to a combination of early myelination (causing an unusually low excitatory threshold) and delayed development of inhibitory mechanisms. Mice were injected intraperitoneally with the compound specified in Table I below or with vehicle control, 30 minutes prior to being placed in a bell jar and turning on the auditory stimulus (12 KHz sine wave at 110-120 db). Administered doses are specified in Table I as milligram of compound per kilogram bodyweight of mouse. The auditory stimulus was left on for 60 seconds and mice reactions were timed and recorded. Percentage inhibition was determined with reference to vehicle controls. Results are shown in Table I below. TABLE I Audiogenic Ex- Response ample Compound Dose % No. Name (mg/kg) Inhib. Salt 1 N-carboximidamide-r-2, c-6-di(4- 10 42 mesylate methylphenyl)piperidine 2 N-carboximidamide-r-2, c-6-di(4- 10 69 HCl isopropylphenyl)piperidine This invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of this disclosure, may make modifications and improvements within the spirit and scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to certain imine-substituted heterocyclic compounds, and methods of treatment and pharmaceutical compositions that utilize or comprise one or more such compounds. Compounds of the invention are particularly useful for the treatment or prophylaxis of neurological injury and neurodegenerative disorders. 2. Background Nerve cell death (degeneration) can cause potentially devastating and irreversible effects for an individual and may occur e.g. as a result of stroke, heart attack or other brain or spinal chord ischemia or trauma. Additionally, neurodegenerative disorders involve nerve cell death (degeneration) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome and Korsakoff's disease. Therapies have been investigated to treat nerve cell degeneration and related disorders, e.g., by limiting the extent of nerve cell death that may otherwise occur to an individual. See, e.g., N. L. Reddy et al., J. Med. Chem., 37:260-267 (1994); and WO 95/20950. The compound MK-801 has exhibited good results in a variety of in vivo models of stroke. See B. Meldrum, Cerbrovascular Brain Metab. Rev., 2:27-57 (1990); D. Choi, Cerbrovascular Brain Metab. Rev., 2:105-147 (1990). See also Merck Index, monograph 3392, 11th ed., 1989. For example, MK-801 exhibits good activity in mouse audiogenic tests, a recognized model for evaluation of neuroprotective drugs. See, e.g., M. Tricklebank et al., European Journal of Pharmacology, 167:127-135 (1989); T. Seyfried, Federation Proceedings, 38(10):2399-2404 (1979). However, MK-801 also has shown toxicity and further clinical development of the compound is currently uncertain. See J. W. Olney et al., Science, 244:1360-1362 (1989); W. Koek et al., J. Pharmacol. Exp. Ther., 252:349-357 (1990); F. R. Sharp et al., Society for Neuroscience Abstr. , abstr. no. 482.3 (1992). It thus would be highly desirable to have new neuroprotective agents, particularly agents to limit the extent or otherwise treat nerve cell death (degeneration) such as may occur with stroke, heart attack or brain or spinal cord trauma, or to treat neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Down's Syndrome and Korsakoff's disease.
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<SOH> SUMMARY OF THE INVENTION <EOH>In a first aspect, the present invention provides imine-substituted compounds of the following Formula I: wherein Z is sulfur, oxygen, carbon or nitrogen; m and n are each independently an integer from 0-to 4, and the sum of m and n is at least 2, preferably is 3, 4, 5 or 6, more preferably 3, 4 or 5; each X is independently substituted or unsubstituted alkyl preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylsilyl preferably having 1 to about 20 carbon atoms and 1 or more Si atoms; substituted or unsubstituted alkenyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkynyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkoxy preferably having from 1 to about 20 carbon atoms, including haloalkoxy; substituted or unsubstituted alkylthio preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylamino preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfinyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfonyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted carbocyclic aryl preferably having at least about 6 ring carbon atoms; substituted or unsubstituted aralkyl preferably having from 7 to about 18 carbons; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms; p is an integer equal to 0 (where the ring is substituted only by the depicted —C(═NH)NH 2 substituent) to 14, more typically from 0 to about 4; and pharmaceutically acceptable salts thereof. Substituted or unsubstituted methylene (—CH 2 —) is a generally preferred Z ring member. Generally preferred X groups include substituted and unsubstituted alkyl, substituted and unsubstituted alkylsilyl, substituted and unsubstituted alkenyl, substituted and unsubstited alkynyl, substituted and unsubstituted alkylthio, substituted and unsubstituted alkylamino, substituted and unsubstituted alkylsulfinyl, substituted and unsubstituted alkylsulfonyl, substituted and unsubstituted aralkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaromatic or heteroalicyclic groups. Particularly preferred X groups included substituted and unsubstituted alkyl and substituted and unsubstituted carbocyclic aryl, particularly substituted and unsubstituted naphthyl or phenyl such as naphthyl or phenyl substituted by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio and ethylthio, and alkylsilyl preferably having 1 to about 15 carbon atoms. It is understood that the imine-substituted ring nitrogen shown in the above formula generally would not be substituted by an X group. It is further understood that the ring methylene (CH 2 ) groups (which include Z where Z is carbon) of the above Formula I will include only a single hydrogen if the methylene unit is mono-substituted by an X group, i.e. the methylene unit will be (CHX), or the methylene unit will contain no hydrogens if di-substituted by X groups, i.e. the methylene unit will be (CXX). It is also understood the range of p values will depend in part on the sum of m and n as well as the valence of the Z ring substituent. Thus, for example, if the sum of m and n is 4 and without limitation on the Z ring member, p will be an integer of from 0 to 10, but if Z is specified to be oxygen, then p will be an integer of from 0 to 8, or if Z is nitrogen then p will be an integer of from 0 to 10. Generally preferred compounds of Formula I include six-member ring compounds (i.e. where the sum of m and n above is four), particularly compounds of the following Formula Ia: wherein Z and X are each the same as defined above for Formula I; p′ is an integer of from 0 (where the ring is substituted only by the —C(═NH)NH 2 substituent) to 10, more typically from 0 to about 4; and pharmaceutically acceptable salts thereof. Particularly preferred compounds of Formula I are substituted piperidines of the following Formula Ib: wherein X is the same as defined above for Formula I; p″ is an integer of from 0 (where the ring is substituted only by the depicted imine) to 10, more typically from 0 to about 4; and pharmaceutically acceptable salts thereof. Generally preferred W and Y groups include substituted and unsubstituted alkyl, substituted and unsubstituted alkylsilyl, substituted and unsubstituted alkenyl, substituted and unsubstituted alkynyl, substituted and unsubstituted alkylthio, substituted and unsubstituted alkylamino, substituted and unsubstituted alkylsulfinyl, substituted and unsubstituted alkylsulfonyl, substituted and unsubstituted aralkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaromatic or heteroalicyclic groups. Particularly preferred W and Y groups included substituted and unsubstituted alkyl and substituted and unsubstituted carbocyclic aryl, particularly substituted and unsubstituted naphthyl or phenyl such as naphthyl or phenyl substituted by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio, and alkylsilyl preferably having 1 to about 15 carbon atoms. In a second aspect, imine-substituted compounds are provided that are substituted by a group other than hydrogen on the imine or adjacent non-cyclic nitrogen. Preferred are compounds of the following Formula II: wherein Z, X, p, m and n are the same as defined above for Formula I; R, R 1 and R 2 are each independently hydrogen; hydroxy; substituted or unsubstituted alkanoyl having from 1 to about 20 carbon atoms; substituted or unsubstituted alkanoyloxy having from 1 to about 20 carbon atoms; substituted or unsubstituted alkyl preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkenyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkynyl preferably having from 2 to about 20 carbon atoms; substituted or unsubstituted alkoxy preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylthio preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylamino preferably having from 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfinyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted alkylsulfonyl preferably having 1 to about 20 carbon atoms; substituted or unsubstituted carbocyclic aryl having at least about 6 ring carbon atoms; or a substituted or unsubstituted heteroaromatic or heteroalicyclic group having from 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms, with at least one of R, R 1 and R 2 being other than hydrogen; and pharmaceutically acceptable salts thereof. Preferred compounds of Formula II include six-member ring compounds (sum of m and n above is four), particularly compounds of the following Formula IIa: wherein Z and X are each the same as defined above for Formula I; p is an integer of from 0 to 10, more typically 0 to about 4; R, R 1 and R 2 are each the same as defined above for Formula II; and pharmaceutically acceptable salts thereof. Substituted piperidine compounds are generally preferred, i.e. where Z is carbon. Also preferred are compounds of Formula II that have at least two ring substituents (p≧2 in Formula II), particularly 2,6-substituted compounds of Formula IIa, such as the following piperidine compounds of Formula IIb: wherein W and Y are the same as defined above for Formula Ic; R, R 1 and R 2 are each the same as defined above for Formula II; and pharmaceutically acceptable salts thereof. Generally preferred X, W and Y groups of compounds of Formula II, IIa and IIb include substituted and unsubstituted alkyl, substituted and unsubstituted alkylsilyl, substituted and unsubstituted alkenyl, substituted and unsubstituted alkynyl, substituted and unsubstituted alkylthio, substituted and unsubstituted alkylamino, substituted and unsubstituted alkylsulfinyl, substituted and unsubstituted alkylsulfonyl, substituted and unsubstituted aralkyl, substituted and unsubstituted carbocyclic aryl, and substituted and unsubstituted heteroaromatic or heteroalicyclic groups. Particularly preferred X, W and Y groups of compounds of Formula II, IIa and IIb include substituted and unsubstituted alkyl and substituted and unsubstituted carbocyclic aryl, particularly substituted or unsubstituted naphthyl or phenyl such as naphthyl or phenyl substituted by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio or ethylthio, and alkylsilyl preferably having 1 to about 15 carbon atoms. Preferred R and R 1 groups of compounds of Formulae II, IIa and IIb include substituted and unsubstituted carbocyclic aryl and heteroaromatic and heteroalicyclic groups. Particularly preferred R and R 1 groups are substituted and unsubstituted naphthyl and phenyl groups, such as naphthyl or phenyl substituted at one or more ring positions by alkyl or haloalkyl having 1 to about 6 carbons, halogen, alkylthio, particularly alkylthio having 1 to about 6 carbon atoms such as methylthio. Other preferred R and R 1 groups include hydroxy, alkyl, alkenyl, alkynyl, alkoxy, alkylthio, alkylamino, alkylsulfinyl, alkylsulfonyl, substituted or unsubstituted alkanoyl and substituted or unsubstituted alkanoyloxy. Generally preferred are compounds of Formulae II, IIa and IIb are those where at least of one of R and R 1 is other than hydrogen, and R 2 is hydrogen. As with compounds of Formula I, it is understood with respect to the compounds of Formula II that the depicted imine-substituted ring nitrogen would not be substituted by an X group. It is further understood that the ring methylene groups (CH 2 ) of the above Formula II will include only a single hydrogen if the methylene unit is mono-substituted by an X group, i.e. the methylene unit will be (CHX), or the methylene unit will contain no hydrogens if di-substituted by X groups, i.e. the methylene unit will be (CXX). It is also understood the range of p values will depend in part on the sum of m and n as well as the valence of the Z ring substituent. The invention also includes both racemic mixtures and optically enriched mixtures of chiral compounds of the invention. An optically enriched mixture contains substantially more (e.g. about 60%, 70%, 80% or 90% or more) of one enantiomer or diastereoisomer than the other stereoisomer(s). Preferred optically enriched mixtures contain 97% or more, more preferably 98% or more, even more preferably 99% or more of one enantiomer or diastereoisomer than the other stereoisomer(s). Compounds of the invention are useful for a number of therapeutic applications. In particular, the invention includes methods for treatment and/or prophylaxis of neurological conditions/injuries such as epilepsy, neurodegenerative conditions and/or nerve cell death (degeneration) resulting from e.g. hypoxia, hypoglycemia, brain or spinal chord ischemia, retinal ischemia, brain or spinal chord trauma or post-surgical neurological deficits and the like as well as neuropathic pain. The compounds of the invention are especially useful for treatment of a person susceptible or suffering from stroke or heart attack or neurological deficits relating to cardiac arrest, a person suffering or susceptible to brain or spinal cord injury, or a person suffering from the effects of retinal ischemia or degeneration. Compounds of the invention also are useful to treat and/or prevent various neurodegenerative diseases such as Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Alzheimer's disease, Down's Syndrome, Korsakoff's disease, cerebral palsy and/or age-dependent dementia. Compounds of the invention will be further useful to treat and/or prevent migraines, shingles (herpes zoster), epilepsy, emesis and/or narcotic withdrawal symptoms. Also, in addition to treatment of retinal ischemia and related disorders, the invention provides methods for treatment of optic nerve injury/damage. The treatment methods of the invention in general comprise administration of a therapeutically effective amount of one or more compounds of the invention to an animal, including a mammal, particularly a human. Particularly preferred compounds of the invention exhibit good activity in an anticonvulsant in vivo mouse audiogenic assay e.g. as disclosed in Example 6 which follows, preferably about 20% or more inhibition at a dose of a compound of the invention of 20 mg/kg, more preferably about 50% or more or 70% or more inhibition at a dose of 20 mg/kg in such an anticonvulsant in vivo audiogenic assay. The invention also provides pharmaceutical compositions that comprise one or more compounds of the invention and a suitable carrier for the compositions. The invention further provides methods for preparation of compounds of the invention as well as amine (particularly compounds of Formula III below), N-cyano and other compounds useful as intermediates in those preparative methods. Other aspects of the invention are disclosed infra. detailed-description description="Detailed Description" end="lead"?
|
20040628
|
20080909
|
20050922
|
95225.0
| 0
|
AULAKH, CHARANJIT
|
PHARMACEUTICALLY ACTIVE COMPOUNDS AND METHODS OF USE
|
SMALL
| 1
|
CONT-ACCEPTED
| 2,004
|
|||
10,880,475
|
ACCEPTED
|
Method of forming scalloped configuration in curtains
|
A method of forming scalloped configuration in a single or double-layer curtain comprises providing the curtain with a pair of ties with their upper ends attached to the curtain and their lower ends hanging freely. A solid bead having a passageway therethrough is slipped upwardly through each tie to approximately the same height until a scalloped configuration is formed in the curtain.
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1. A method of forming scalloped configuration in a double-layer curtain for hanging from windows, said curtain having a front layer and a back layer, each of said layers being defined by an upper edge and a lower generally parallel edge, and two generally parallel sides, said method comprising: (a) providing two pairs of ties, each tie having an upper end attached to said curtain, and a freely hanging lower end, (b) each of said pairs of ties being attached at their upper ends to one of said curtain layers a finite distance from the top edge and its respective side edge, and (c) slipping through each pair of said ties a solid bead having a passageway therethrough for passage of said ties and raising each bead to approximately the same height until forming the scalloped configuration in said curtain. 2. A method as in claim 1 wherein each of said beads is spherical in shape having a central through passageway. 3. A method as in claim 1 wherein the ends of each pair of ties which are attached to the curtain lie on a common line which is generally parallel to the top and bottom edges of each of said layers. 4. A method as in claim 2 wherein the ends of each pair of ties which are attached to the curtain lie on a common line which is generally parallel to the top and bottom edges of each of said layers. 5. A method of forming a scalloped configuration in a single layer curtain, said curtain layer being defined by an upper edge and a lower generally parallel edge, and two generally parallel side edges, said method comprising: (a) providing two pairs of ties, each tie having an upper end attached to said curtain, and a freely hanging lower end, (b) each of said pairs of ties being attached at their upper ends to said curtain a finite distance from the top edge and respective side edge, and (c) slipping through each pair of said ties a solid bead having a passageway therethrough for passage of said ties and raising each bead to approximately the same height until forming the scalloped configuration in said curtain. 6. A method as in claim 5 wherein each of said beads is spherical in shape having a central through passageway. 7. A method as in claim 5 wherein the ends of each pair of ties which are attached to the curtain lie on a common line which is generally parallel to the top and bottom edges of each of said layers. 8. A method as in claim 6 wherein the ends of each pair of ties which are attached to the curtain lie on a common line which is generally parallel to the top and bottom edges of each of said layers.
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RELATED PATENT APPLICATIONS This application is related to provisional patent application Ser. No. 60/555,921 filed Mar. 24, 2004. FIELD OF THE INVENTION This invention relates generally to swaging curtains and draperies and is specifically related to a method of forming scalloped configuration in curtains and draperies used for hanging from windows, thus imparting desired decorative and aesthetic appearance thereto. More specifically, this invention provides such method in an extremely simple, effective and quick manner. BACKGROUND OF THE INVENTION Curtains and draperies are frequently used to hang from windows and it is often desirable to gather the curtain material into folds for decorative and aesthetic effects. Gathering the curtain materials into decorative folds and fixing it into position can be accomplished by hand, but needless to say that is cumbersome and time consuming task. The difficulty is exacerbated when it is desired to hand decorative curtains from high windows such as theatres, art galleries or over large windows at homes. Several prior art patents describe different methods of handing draperies for hanging from windows. An early patent, i.e., Design Pat. No. 14,621 issued Feb. 5, 1884 shows a design for a lambrequin wherein an upper portion shapes two festoons over the lower portion, and has two ends falling below the sides of the lower portion. U.S. Pat. No. 2,668,587 issued Feb. 9, 1954 describes and illustrates a class of draped window curtains having a “tie back” construction which forms an integral part of the curtain as shown in FIGS. 1 and 3. U.S. Pat. No. 2,671,508 issued Mar. 9, 1954 describes improvements in hanging draperies. To a valance drapery made from a piece of rectangular material are secured eyelets arranged along parallel lines running longitudinally of the material thereby forming folds or pleats when the eyelets are threaded together. U.S. Pat. No. 3,001,579 issued Sep. 26, 1961 describe the use of swaging tape which is applied to the material to be gathered, the tape being applied to the drapery material by sewing or stitching operation. None of the previously described prior art methods of other known methods provide a simple, effective and inexpensive method of gathering the drapery material in order to form a desired scalloped configuration as is possible by the method of this invention. Therefore, it is the object of this invention to provide a method of gathering drapery material to form a scalloped configuration for hanging the drapery over a window. It is a further object of this invention to provide a method of forming a scalloped-shaped design in draped curtains while the curtain is hanging from a window. It is also an object of the present invention to provide such method which can readily be used in homes with simplicity and efficiency at minimal costs. The foregoing and other objects of this invention will become more apparent from the ensuing detailed description and with reference to the accompanying drawings. SUMMARY OF THE INVENTION The present invention provides a method for forming scalloped configuration in single layer or multi-layer (e.g., double layer) curtains. A double layer curtain comprises a front panel and a back panel with each panel being defined by an upper edge and a lower generally parallel edge, and two generally parallel sides. In applying the method of this invention to such curtains, the curtain is provided with two pairs of spaced apart ties, each tie having an upper end conjointly attached to one of said panels a finite distance from the top edge and its respective side edge, and are freely hanging at their lower ends. A solid object such as a bead, which may be spherical in shape, and has a channel or passageway extending through the bead, is slipped through each pair of ties and the bead is raised until a scalloped configuration is formed which is discernible by visual observation. At that point, the ends of the ties are bowed to prevent the beads from falling down and remain in their scalloped configuration position. By untying the bows, the beads may be slipped down through the ties and the curtain will return to its original position. BRIEF DESCRIPTION OF THE DRAWINGS Referring to the different figures in the drawings wherein like reference numerals are used to designate like parts; FIG. 1 is a front view of a double-layer curtain having a front layer or panel and a back layer or panel with two pairs of ties as shown and hereinafter described; FIG. 2 is a view similar to FIG. 1 with each pair of ties is inserted through a spherical bead having a channel for passage of the ties therethrough, wherein the ties are in initial free-hanging positions; FIG. 3 is a front view similar to FIG. 2 but wherein the beads are raised to form the desired scalloped design in the curtain; FIG. 4 is a side view of FIG. 2; and FIGS. 5-8 are views corresponding to FIGS. 1-4, respectively, for a single-layer curtain. DETAILED DESCRIPTION OF THE INVENTION Referring first to FIG. 1, there is shown a curtain 10 comprising a front layer or panel 11 and a back layer or panel 12 stitched or sewn together along the top of each panel to form a channel or passageway 13 for the insertion of a curtain rod (not shown) therethrough for hanging the curtain from a window. The panel 11 is defined by the longitudinal, generally parallel top and bottom edges 11a and 11b, a generally vertical left side edge 11c and right generally parallel side edge 11d. Also, the back panel 12 is defined by similar top and bottom edges 12a, 12b and similar side edges 12c, 12d. A pair of ties 14a, 14b (e.g., ribbons or bands made from the same or different material as the curtain) are attached or sewn to the curtain at their conjoint ends such as at 14c, a finite desired distance from the top edge and left side of the curtain panel, and are normally freely hanging at their lower ends 14d, 14e. A similar pair of ties 15a, 15b are also attached or sewn to the curtain at their conjoint ends such as at 15c, a finite desired distance from the top edge and right edge of the curtain panel, and are normally freely hanging at their lower ends 15d, 15e. Preferably the conjoint ends 14c and 15c lie on a common line 16 which is generally parallel to the top and bottom edges, and the distance between each conjoint end 14c and 15c from their respective sides and edges are approximately equal in order to form the desired scalloped design as herein described. Referring to FIG. 2, there is shown the beads 17 and 18; one for each pair of ties. Each bead is usually spherical or round in shape having a central passageway extending centrally therethrough, between the top and bottom of the bead for insertion and passage of each pair of said ties through each bead. The width or diameter of the passageway must of course be large enough to accommodate the pair of ties such that the bead can be slidably raised and lowered as desired. In order to form the desired scallop design in the curtain panels, the ties 14a, 14b are inserted through the passageway in the bead 17 and the bead 17 is raised to the desired height until it results in the formation of part of the scalloped design 19a at which point the ties or ribbons may be tied into a bow as in 20a. Similarly, the ties 15a, 15b are slipped through the passageway in the bead 18 and bead 18 is raised to the desired height, which is usually equal to the height to which the bead 17 is raised, to form the other part of the scalloped design 19b and the ties are then bowed as in 20a after forming of the scalloped design 19a, 19b, 19c, the ties are bowed as aforesaid remain raised while the curtain is hanging from the window. In order to remove the curtain, such as for cleaning, the bows are untied and the beads are slipped down to their initial positions. The scalloped design may result in ruffled or gathered portions, if desired, for improved aesthetic appearance. Thus, a quick and simple method is provided for forming scalloped designs in a curtain which does not require the complicated and time-consuming operation normally required for forming the desired curtain designs. The method of formation of scalloped design for a mono-layered curtain is described by reference to FIGS. 5-8 of the drawings. In FIG. 5 the curtain 110 is formed by a single layer or panel 111 having an overlapped and stitched or sewn top segment which forms a passageway 112 for the passage of a curtain rod (not shown). The panel 111 is defined by the top, and lower generally parallel edges 111a, 111b, and generally parallel side edges 111c, 111d. A pair of ties 114 and 114b (e.g., ribbons or bands made from the same or different material as the curtain) are attached or sewn to the panel 111 at their conjoint ends such as 114c, a finite desired distance from the top edge and left side of said panel, and are normally freely hanging at their lower ends 14d, 14e. A similar pair of ties 115a, 115b are also attached or sewn to the panel 111 at their conjoint point 115c, a finite desired distance from the top edge and left side of said panel, and are normally freely hanging at their lower ends 115d, 115e. Preferably the conjoint ends 114c and 115c lie on a common line 116 which is generally parallel to the top and bottom edges, and the distances between each conjoint end 114c and 115c from its respective sides and edges are approximately equal in order to form the desired scalloped configuration in the curtain panel. The method of forming the scalloped design in the single layer curtain panel 111 is the same as hereinbefore described for the double-layer curtain, using the beads 117, 118 each of which has a central passageway extending between the top and bottom of each bead. As in the double layer curtain, in order to form the scalloped configuration in the single layer curtain, each pair of ties is passed through the passageway of each bead, each bead is raised by slipping up to the desired height until forming the scalloped configurations defined by the curtain panel segments 119a, 119b and 119c, and each pair of ties may be bowed as in 120 and 121. Once again the scalloped design may result in gathered or ruffled portion which enhances the aesthetic view of the curtain. Although a spherical bead is used in the method described herein, the shape of the bead is not critical, per se, so long as the bead is provided with a through passage for insertion of the ties such that the bead can be manipulated by sliding it through and up to the desired height in the curtain. Other changes and modifications are suggested from the foregoing detailed description without departing from the scope of the present invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Curtains and draperies are frequently used to hang from windows and it is often desirable to gather the curtain material into folds for decorative and aesthetic effects. Gathering the curtain materials into decorative folds and fixing it into position can be accomplished by hand, but needless to say that is cumbersome and time consuming task. The difficulty is exacerbated when it is desired to hand decorative curtains from high windows such as theatres, art galleries or over large windows at homes. Several prior art patents describe different methods of handing draperies for hanging from windows. An early patent, i.e., Design Pat. No. 14,621 issued Feb. 5, 1884 shows a design for a lambrequin wherein an upper portion shapes two festoons over the lower portion, and has two ends falling below the sides of the lower portion. U.S. Pat. No. 2,668,587 issued Feb. 9, 1954 describes and illustrates a class of draped window curtains having a “tie back” construction which forms an integral part of the curtain as shown in FIGS. 1 and 3 . U.S. Pat. No. 2,671,508 issued Mar. 9, 1954 describes improvements in hanging draperies. To a valance drapery made from a piece of rectangular material are secured eyelets arranged along parallel lines running longitudinally of the material thereby forming folds or pleats when the eyelets are threaded together. U.S. Pat. No. 3,001,579 issued Sep. 26, 1961 describe the use of swaging tape which is applied to the material to be gathered, the tape being applied to the drapery material by sewing or stitching operation. None of the previously described prior art methods of other known methods provide a simple, effective and inexpensive method of gathering the drapery material in order to form a desired scalloped configuration as is possible by the method of this invention. Therefore, it is the object of this invention to provide a method of gathering drapery material to form a scalloped configuration for hanging the drapery over a window. It is a further object of this invention to provide a method of forming a scalloped-shaped design in draped curtains while the curtain is hanging from a window. It is also an object of the present invention to provide such method which can readily be used in homes with simplicity and efficiency at minimal costs. The foregoing and other objects of this invention will become more apparent from the ensuing detailed description and with reference to the accompanying drawings.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a method for forming scalloped configuration in single layer or multi-layer (e.g., double layer) curtains. A double layer curtain comprises a front panel and a back panel with each panel being defined by an upper edge and a lower generally parallel edge, and two generally parallel sides. In applying the method of this invention to such curtains, the curtain is provided with two pairs of spaced apart ties, each tie having an upper end conjointly attached to one of said panels a finite distance from the top edge and its respective side edge, and are freely hanging at their lower ends. A solid object such as a bead, which may be spherical in shape, and has a channel or passageway extending through the bead, is slipped through each pair of ties and the bead is raised until a scalloped configuration is formed which is discernible by visual observation. At that point, the ends of the ties are bowed to prevent the beads from falling down and remain in their scalloped configuration position. By untying the bows, the beads may be slipped down through the ties and the curtain will return to its original position.
|
20040701
|
20070508
|
20050929
|
77348.0
| 1
|
JOHNSON, BLAIR M
|
METHOD OF FORMING SCALLOPED CONFIGURATION IN CURTAINS
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SMALL
| 0
|
ACCEPTED
| 2,004
|
|||
10,880,762
|
ACCEPTED
|
Power supply detection method, apparatus, and system
|
Circuits in a processor may provide an indication that power supplies are ready when waking from a reduced power state. The processor may include timers to measure a period of time, and may utilize voltage detectors to detect the voltages on the power supplies. A control register in the processor may influence the operation.
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1. A method comprising: requesting that a power supply ramp up a voltage; detecting when the power supply has ramped up the voltage; and based on a control field in a register, conditionally waking up a sleeping circuit when the power supply has ramped up the voltage. 2. The method of claim 1 further comprising starting a timer. 3. The method of claim 2 wherein conditionally waking up a sleeping circuit when the power supply has ramped up the voltage comprises: if the power supply has ramped up the voltage prior to the timer timing out, and the control field is in a first state, waking up a sleeping circuit; and if the timer times out, waking up the sleeping circuit. 4. The method of claim 1 wherein requesting that a power supply ramp up a voltage comprises requesting that a bank of power supplies ramp up. 5. The method of claim 4 wherein detecting when the power supply has ramped up comprises detecting when all of the bank of power supplies has ramped up. 6. The method of claim 1 wherein requesting that a power supply ramp up a voltage comprises requesting that two banks of power supplies ramp up. 7. The method of claim 6 wherein detecting when the power supply has ramped up comprises detecting when all of the power supplies in a first bank has ramped up and detecting when all of the power supplies in a second bank has ramped up. 8. The method of claim 7 further comprising: starting a first timer corresponding to the first bank; and starting a second timer corresponding to the second bank. 9. The method of claim 8 wherein conditionally waking up a sleeping circuit when the power supply has ramped up the voltage comprises: if the first bank of power supplies has ramped up prior to the first timer timing out, and a control field is in a first state, providing an indication that the first bank has ramped up; if the first timer times out, providing the indication that the first bank has ramped up; if the second bank of power supplies has ramped up prior to the second timer timing out, and the control field is in the first state, providing an indication that the second bank has ramped up; if the second timer times out, providing the indication that the second bank has ramped up; and when the first and second indications have been provided, waking up the sleeping circuit. 10. A processor comprising a state machine to determine when a power supply is ready, wherein the state machine is responsive to a timer that specifies a time to wait and is responsive to a signal from a voltage detection circuit that detects the condition of the power supply. 11. The processor of claim 10 further comprising the voltage detection circuit. 12. The processor of claim 10 further comprising an external signal node to receive the signal from the voltage detection circuit. 13. The processor of claim 10 wherein the processor includes a configuration register, and the state machine conditionally ignores the signal from the voltage detection circuit based on a value of a control field in the configuration register. 14. The processor of claim 10 wherein the state machine is responsive to a plurality of signals from voltage detection circuits that detect voltages of a plurality of power supplies. 15. The processor of claim 14 wherein the plurality of power supplies are grouped into two groups, and the state machine is responsive to one signal corresponding to each of the two groups. 16. The processor of claim 10 wherein the state machine is further responsive to a field in a configuration register, and wherein the state machine provides an indication that the power supply is ready when the timer times out or when the voltage detection circuit indicates that the power supply is ready and the field in the configuration register is set to indicate that the voltage detection circuit is not to be ignored. 17. A processor comprising: a register to hold a first control bit corresponding to a first group of at least one power supply, and a second control bit corresponding to a second group of at least one power supply; and a state machine coupled to the register to receive values of the first and second control bits, and to use different criteria to determine states of the power supplies based on the values of the first and second control bits. 18. The processor of claim 17 wherein the different criteria include a timer and the output of a voltage detector. 19. The processor of claim 18 wherein the control register includes a field to program the timer. 20. The processor of claim 19 further comprising the voltage detector. 21. The processor of claim 17 further comprising a plurality of voltage detectors to detect power supply voltages of the first group, and to provide a signal to the state machine indicating that the power supply voltages of the first group are ramped up. 22. The processor of claim 17 further comprising a first timer corresponding to the first group and a second timer corresponding to the second group, the first and second timers coupled to provide signals to the state machine as criteria to determine states of the power supplies. 23. An electronic system comprising: an antenna; an analog circuit coupled to the antenna; and a processor comprising a state machine to determine when a power supply is ready, wherein the state machine is responsive to a timer that specifies a time to wait and is responsive to a signal from a voltage detection circuit that detects the condition of the power supply. 24. The electronic system of claim 23 wherein the processor includes a configuration register, and the state machine conditionally ignores the signal from the voltage detection circuit based on a value of a control field in the configuration register. 25. The electronic system of claim 23 wherein the state machine is responsive to a plurality of signals from voltage detection circuits that detect voltages of a plurality of power supplies. 26. The electronic system of claim 25 wherein the plurality of power supplies are grouped into two groups, and the state machine is responsive to one signal corresponding to each of the two groups.
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FIELD The present invention relates generally to electronic systems, and more specifically to the ramping up of power supplies in electronic systems. BACKGROUND Processors typically receive power to operate when included in a system. The power may be received directly from one or more batteries, or from a power management integrated circuit or system, or the like. When waking from a reduced power mode, it may take time for power supply voltages to stabilize, or to “ramp up.” For example, a processor may be in a sleep mode in which one or more power supply voltages may not be provided to the processor. When exiting the sleep mode, it may take time for the power supply voltages to reach a sufficient value for the processor to operate correctly. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an electronic system in accordance with various embodiments of the present invention; FIG. 2 shows a register; FIGS. 3 and 4 show state machine diagrams; FIG. 5 shows a flowchart in accordance with various embodiments of the present invention; and FIGS. 6 and 7 show electronic systems in accordance with various embodiments of the present invention. DESCRIPTION OF EMBODIMENTS In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the spirit and scope of the invention. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled. In the drawings, like numerals refer to the same or similar functionality throughout the several views. FIG. 1 shows an electronic system in accordance with various embodiments of the present invention. Electronic system 100 includes back-up battery 110, main battery 120, power mode integrated circuit (PMIC) 130, processor 140, and memory 150. Processor 140 may be any type of processor. For example, in some embodiments, processor 140 may be a microprocessor, a digital signal processor, an embedded micro-controller, or the like. In some embodiments, PMIC 130 is coupled to processor 140 by multiple signal paths and other conductors. For example, as shown in FIG. 1, PMIC 130 provides processor 140 with power supply voltages on power supplies 134 and back-up power supplies 136. Also, processor 140 provides PMIC 130 with power supply enable signals 131 and 132, labeled PSEN1 and PSEN2, respectively. In operation, PMIC 130 provides power to processor 140 using power supplies 134 and back-up power supplies 136. In some embodiments, each of power supplies 134 and 136 includes two conductors: one for a power supply voltage, and one for a reference voltage, such as ground. In other embodiments, each of power supplies 134 and 136 includes a single conductor to provide a power supply voltage, and a separate conductor is provided in common for all of power supplies 134 and 136. As shown in FIG. 1, power supplies 134 includes N separate supplies, and back-up power supplies 136 includes M separate power supplies. In the various embodiments of the present invention, any number of power supplies 134 and back-up power supplies 136 may be provided to processor 140 by PMIC 130. For example, power supplies 134 may include separate power supply lines to power various portions of processor 140. Power supplies 134 may include a separate power supply to power a processor core within processor 140, an internal memory within processor 140, and other functional blocks within processor 140. Each of power supplies 134 may be at a separate voltage, or each of power supplies 134 may be at a common voltage. In some embodiments, different voltages are provided on power supplies 134 based on power requirements of processor 140. Back-up power supplies 136 may include one or more power supply voltages to provide back-up power to processor 140. PMIC 130 may generate various voltages for power supplies 134 and 136 in any manner. For example, PMIC 130 may include linear regulators, switching regulators, or the like. In some embodiments, PMIC 130 may be able to turn on and off power supplies 134 and 136 at the request of processor 140. For example, PMIC 130 may enable power supplies 134 when processor 140 asserts PSEN1, and may disable power supplies 134 when processor 140 de-asserts PSEN1. Likewise, PMIC 130 may enable power supplies 136 when processor 140 asserts PSEN2, and may disable power supplies 136 when processor 140 de-asserts PSEN2. When processor 140 is in a reduced power mode such as a “sleep mode,” some or all of power supplies 134 or power supplies 136 may be turned off. By asserting PSEN1 and/or PSEN2, processor 140 may request that PMIC 130 turn the power supplies on. As shown in FIG. 1, the power supplies are grouped into two groups: power supplies 134, and backup power supplies 136; and one enable signal is provided to PMIC 130 from processor 140 for each group. In some embodiments, more than two groups of power supplies exist, and more than two power supply enable signals exist. Further, in some embodiments, each power supply may have an enable signal associated therewith. In these embodiments, each power supply may be independently turned on and off. System 100 is shown with two batteries: back-up battery 110, and main battery 120. In the various embodiments of the present invention, any number of batteries may be utilized. For example, in some embodiments, a single battery is utilized for both main power and back-up power. Also for example, in some embodiments, many batteries are used, and in still further embodiments, a battery charger with components such as a transformer and rectifier may also be used. Processor 140 includes state machine 142, register 144, timers 162 and 164, and voltage detectors 166 and 168. State machine 142 may operate to determine whether power supplies 134 and backup power supplies 136 are sufficiently ramped up to provide the “supplies ready” signal on node 143. By providing the “supplies ready” signal, state machine 142 may provide an indication to other blocks (not shown) within processor 140 that the power supplies are ready to be used. State machine 142 may utilize various criteria to determine whether power supplies 134 and backup power supplies 136 are ready. For example, state machine 142 may use information from timers and voltage detectors. State machine 142, and the various embodiments thereof, is described in more detail below with reference to FIGS. 3 and 4. In some embodiments, voltage detectors 166 includes N separate voltage detection circuits to provide separate voltage detection capabilities for each of power supplies 134, and voltage detectors 168 includes M separate voltage detection circuits to provide separate voltage detection capabilities for each of backup power supplies 136. In other embodiments, voltage detectors 166 includes a single voltage detection circuit to detect a voltage on one of power supplies 134, and voltage detectors 168 includes a single voltage detection circuit to detect a voltage on one of backup power supplies 136. In some embodiments, voltage detectors 166 may provide N output signals to state machine 142, where each output signal corresponds to one of power supplies 134. In other embodiments, voltage detectors 166 may provide one output signal to state machine 142 to represent the state of all of power supplies 134. For example, voltage detectors 166 may include one voltage detector for each of power supplies 134, and output signals from each of voltage detectors 166 may be combined logically using an “and” operation, and the resulting signal may be provided to state machine 142. In some embodiments, voltage detectors 168 may provide M output signals to state machine 142, where each output signal corresponds to one of the backup power supplies 136. In other embodiments, voltage detectors 168 may provide one output signal to state machine 142 to represent the state of all of backup power supplies 134. For example, voltage detectors 168 may include one voltage detector for each of backup power supplies 136, and output signals from each of voltage detectors 168 may be combined logically using an “and” operation, and the resulting signal may be provided to state machine 142. Voltage detectors 166 and 168 may include any type of circuitry. For example, voltage detectors 166 and 168 may include passive components such as capacitors and resistors, active components such as transistors and diodes, or any combination. In operation, voltage detectors 166 detect whether a minimum operating voltage exists on power supplies 134, and provides an indication to state machine 142. For example, in embodiments represented by FIG. 1, when PSEN1 is de-asserted, power supplies 134 may be turned off, and one or more of the voltages on power supplies 134 may be less than the minimum operating voltage required by processor 140. When PSEN1 is asserted, power supplies 134 are turned on, and voltages on power supplies 134 begin to increase, or “ramp up.” When the voltage on power supplies 134 has ramped up beyond the minimum operating voltage, voltage detectors 166 provide an indication thereof to state machine 142. Voltage detectors 168 operate in a like manner, and provide an indication of the state of backup power supplies 136 to state machine 142. Timers 162 and 164 provide a mechanism to measure a period of time, and to provide state machine 142 with an indication that the period of time has expired. For example, timers 162 and 164 may be implemented using preloadable digital counters that count down after being preloaded using values held in register 144. When the count equals zero, the time period has expired, and the timer provides an indication thereof to state machine 142. In some embodiments, timers 162 and 164 may operate independently. For example, timers 162 and 164 may be loaded with different values such that each of timers 162 and 164 implements a timer measuring a different period of time. Register 144 may be a configuration register that includes fields that specify the amount of time that each of timers 162 and 164 measure. Further, register 144 may include one or more control bits or status bits provided to state machine 142. For example, register 144 may include one or more control fields to specify whether the outputs of voltage detectors 166 and 168 should be ignored when determining whether to indicate that the power supplies are ready. Further, register 144 may include one or more control fields to specify whether timers 162 and 164 should be utilized when determining whether to indicate that the power supplies are ready. Register 144, and the various embodiments thereof, is described in more detail below with reference to FIG. 2. Processor 140 is shown with a limited number of functional blocks. In some embodiments, processor 140 includes many more functional blocks. For example, processor 140 may include an arithmetic logic unit (ALU), an execution pipeline, control circuitry, and the like. Each of the blocks shown within processor 140 may influence, or maybe influenced by, software being executed within processor 140. For example, in some embodiments, PSEN1 and PSEN2 may be asserted under software control, and in other embodiments, PSEN1 and PSEN2 may be asserted by state machine 142 or other control circuitry. Further, in some embodiments, portions of the blocks shown in processor 140 may be implemented in software or in a combination of hardware and software. The various embodiments of the present invention are not limited in this respect. Memory 150 represents an article that includes a machine readable medium. For example, memory 150 represents any one or more of the following: a hard disk, a floppy disk, random access memory (RAM), read only memory (ROM), FLASH memory, CDROM, or any other type of article that includes a medium readable by processor 140. Memory 150 can store instructions for performing the execution of the various method embodiments of the present invention. In operation, processor 140 reads instructions and data from memory 150 and performs actions in response thereto. For example, processor 140 may read from, or write to, register 144 in response to instructions read from memory 150. Also for example, processor 140 may access instructions from memory 140 when a reduced power mode is to be entered, and may de-assert one or both of PSEN1 and PSEN2. Although processor 140 and memory 150 are shown separate in FIG. 1, embodiments exist that combine the circuitry of processor 140 and memory 150 in a single integrated circuit. For example, memory 150 may be an internal memory within processor 140 or may be a microprogram control store within processor 140. FIG. 2 shows a register in accordance with various embodiments of the present invention. Register 144 is shown in FIG. 2 including timer load value 202, timer load value 204, and detector control field 206. Timer load value 202 is a value that gets loaded into timer 162 (FIG. 1) when a power supply ramp up process is started. Likewise, timer load value 204 is loaded into timer 164 when the power supply ramp up process is started. Timer load values 202 and 204 are fields within register 144, and may be of any length. In some embodiments, timer load values 202 and 204 are numbers that represent a number of clock cycles having a particular period. For example, a time-keeping oscillator may run at a particular frequency, and each count of timer load values 202 and 204 may correspond to one period of the oscillator signal, although the various embodiments of the present invention are not so limited. Timer load values 202 and 204 correspond to the amount of time a processor will wait after enabling power supplies and before indicating the power supplies are ready. Detector control field 206 specifies whether state machine 142 (FIG. 1) ignores the output of voltage detectors when determining whether power supplies have ramped up. For example, when detector control field 206 is set to “ignore,” a state machine responsive to register 144 will only take into account timers when determining if power supplies have fully ramped up. Alternatively, when detector control field 206 is set to “do not ignore,” a state machine will take into account voltage detector outputs as well as timer outputs. In some embodiments, detector control field 206 is one bit in length. For example, one bit within detector control field 206 may be used to specify whether to ignore all voltage detectors. In other embodiments, detector control field 206 is more than one bit in length. For example, detector control field 206 may include a first control bit specifying whether to ignore one group of voltage detectors, and may include a second control bit specifying whether to ignore another group of voltage detectors. In still further embodiments, multiple detector control fields exist. FIG. 3 shows a state machine diagram in accordance with various embodiments of the present invention. In some embodiments, state machine diagram 300 corresponds to the operation of any of the various state machine embodiments described herein. For example, state machine diagram 300 may correspond to the operation of state machine 142 (FIG. 1). As used herein, the term “state machine” may refer to an article of hardware, such as state machine 142 (FIG. 1). The term “state machine” may also refer to acts performed by hardware or by a hardware/software combination. For example, state machine diagram 300 may also be referred to as a state machine. State 310 represents a mode that a processor may be in, and a mode that a processor may wake from. For example, state 310 may represent any reduced power mode that a processor may enter. In some embodiments, this may correspond to a reduced power mode that has a subset of the available power supplies turned off, or may correspond to a power saving mode that has all of the power supplies turned off. When waking from the mode represented by state 310, state machine 300 transitions to state 320 where supplies are enabled. This may correspond to asserting power supply enable signals, such as PSEN1 and PSEN2, as shown in FIG. 1. At state 330, the timers are loaded and at state 340, the timers count down. The timers referred to in states 330 and 340 may correspond to timers 162 and 164 (FIG. 1). The timers may be loaded using timer load values 202 and 204 from register 144 (FIG. 2). State machine 300 will exit state 340 when the timers have timed out. State machine 300 will also exit state 340 when the power supplies are detected, and the detector control field 206 is set to “do not ignore.” At state 350, the power supplies are ready and the processor executing state machine 300 may wake up circuits. State machine 300 provides a processor an ability to set a time delay between enabling power supplies and waking up circuits, and also allows the time delay to be shortened if the power supplies are detected to have ramped up more quickly. In some embodiments, the time delays and the control fields in register 144 are set by a manufacturer, and are not available to be modified by an end user or a systems integrator. In other embodiments, the timer values and control fields are available to modified, allowing systems integrators and end users to adjust the behavior of state machine 300. FIG. 4 shows a state machine diagram in accordance with various embodiments of the present invention. State machine 400 begins in either state 410 or state 450 when a processor is in either a deep sleep mode or a sleep mode. When in deep sleep mode at state 410, a processor may begin the process of ramping up the power supplies by enabling power supplies at state 420. This may correspond to asserting power supply enable signals PSEN1 and PSEN2 (FIG. 1). Further, a processor may load timers at state 430. This may correspond to loading timers 162 and 164 from timer load values within register 144. As shown in FIG. 4, state 430 is entered after state 420, but this is not a limitation of the present invention. For example, loading the timers may occur before or concurrently with enabling power supplies. At state 440, timer 1 counts down. In some embodiments, timer 1 is used to set a maximum delay to wait for one group of power supplies to ramp up. For example, timer 1 may correspond to the maximum ramp up time of either power supplies 134 or backup power supplies 136 (FIG. 1). State machine 400 leaves state 440 when timer 1 has timed out. This corresponds to the passing of a period of time specified by timer load value 202 in register 144 (FIG. 2). State machine 400 will also exit state 440 if voltage detectors have detected that the power supplies have ramped up and the detector control field 206 within register 144 is set to “do not ignore.” When state machine 400 exits state 440, it enters state 480 where timer 2 continues to count down. State 480 may also be entered from the left side of the diagram in FIG. 4 which includes states 450, 460, and 470. When in state 450, the processor is in a sleep mode and power supplies are enabled at state 460, and timer 2 is loaded at state 470. When a processor begins state machine 400 in sleep mode 450, only one of the two timers is loaded and only one of the two timers is set to count down. This is shown at states 470 and 480. State machine 400 will exit state 480 when timer 2 times out. This corresponds to a period of time equal to the time specified by timer load value 204. State machine 400 will also exit state 480 when voltage detectors have detected that the power supplies have ramped up, and detector control field 206 in register 144 is set to “do not ignore.” In some embodiments, deep sleep mode 410 may correspond to a reduced power mode in which all power supplies are powered down. For example, referring now back to FIG. 1, during a deep sleep, PSEN1 and PSEN 2 may both be de-asserted, and power supplies 134 and backup power supplies 136 may be turned off. When waking from a deep sleep, one timer is set for power supplies 134, and another timer is set for backup power supplies 136. Further, each of the timers may be bypassed if the corresponding power supplies have been detected and the control field in register 144 is set accordingly. In some embodiments, sleep mode 450 may correspond to a reduced power mode in which less than all power supplies are powered down. For example, when in sleep mode 450, one of PSEN1 and PSEN 2 may be de-asserted, and power supplies 134 may turned off while backup power supplies 136 may still be on. When waking from a sleep mode, only the timer corresponding to power supplies 134 is set, and this timer may be bypassed if power supplies 134 have been detected and the control field in register 144 is set accordingly. In some embodiments, state 480 responds to a control bit in detector control field 206 (FIG. 2) which is separate from the control bit to which state 440 responds. In these embodiments, detector control field 206 may include separate control bits for each group of power supplies, and various states in state machines respond to the separate control bits. State machine 400 has been described with power supplies in two groups, enabled by two signals, timed by two timers, and detected by two sets of voltage detectors. Any number of power supplies, groups of power supplies, timers, and voltage detectors may be included without departing from the scope of the present invention. For example, a state machine may include states corresponding to more than two reduced power modes, and more than two timers and voltage detectors may be utilized to determine when the power supplies have ramped up. FIG. 5 shows a flowchart in accordance with various embodiments of the present invention. In some embodiments, method 500, or portions thereof, is performed by a processor or an electronic system, embodiments of which are described with reference to the various figures. In some embodiments, method 500 is performed by a processor or state machine when power supplies are ramped up. The process may be performed when recovering from a reduced power state, or when a device is turned on. Method 500 is not limited by the particular type of apparatus or software element performing the method. The various actions in method 500 may be performed in the order presented, or may be performed in a different order. Further, in some embodiments, some actions listed in FIG. 5 are omitted from method 500. Method 500 begins at 510 in which a request is performed that a power supply ramp up. In some embodiments, this may correspond to a processor, under either hardware or software control, asserting power supply enable signals such as those shown and described with the various figures. At 520, a timer is started. The timer at 520 may correspond to one or more timers such as timers 162 and 164 (FIG. 1). At 530, if the timer has timed out, then method 500 proceeds to 560 where a circuit is woken up. If, at 530, the timer has not timed out, then method 500 determines if one or more voltage detectors indicate that power supply has ramped up at 540. If the voltage detector indicates that the power supply has ramped up, then if the register is set to not ignore the detector at 550, method 500 wakes up the circuit at 560. If either the voltage detector indicates that the power supply has not ramped up at 540, or the register is set to ignore the detector at 550, then method 500 proceeds back to 530. In some embodiments, the timer referenced at 520 and 530 is a hardware timer such as that shown in FIG. 1. In other embodiments, the timer referenced at 520 and 530 may be a software timer. Further, in some embodiments, all of method 500 corresponds to software executing on a processor, such as processor 140 (FIG. 1). In some embodiments, method 500 may correspond to enabling a group of power supplies. For example, a group of power supplies such as power supplies 134 may be enabled, and method 500 may determine when a circuit should be woken up based on the state of the group of power supplies. In some embodiments, method 500 may correspond to enabling multiple groups of power supplies. For example, power supplies 134 and backup power supplies 136 may be enabled, and method 500 may determine when a circuit should be woken up based on the states of both groups of power supplies. In these embodiments, multiple timers may be started at 520, and 530 may correspond to determining if either timer has timed out. In some embodiments, portions of method 500 may be duplicated and performed in parallel corresponding to multiple timers and multiple voltage detectors. FIG. 6 shows an electronic system in accordance with various embodiments of the present invention. Electronic system 600 includes back-up battery 110, main battery 120, and PMIC 130, all of which are described above with reference to FIG. 1. Electronic system 600 also includes voltage detectors 610 and 620, and processor 650. Processor 650 includes state machine 642, register 644, and timers 646. In some embodiments, register 644 corresponds to register 144 (FIGS. 1, 2), and timers 646 correspond to timers 162 and 164 (FIG. 1). Further, state machine 642 may correspond to state machine 142 (FIG. 1), and may operate in accordance with any of the state machine embodiments described herein, including those shown in FIGS. 3 and 4. Voltage detectors 610 and 620 correspond in operation to voltage detectors 166 and 168, respectively. Voltage detectors 610 and 620 may be implemented with any type of circuit external to processor 650. For example, voltage detectors 610 and 620 may be implemented using discrete circuitry, or may be implemented in integrated circuits. The manner in which voltage detectors 610 and 620 are implemented is not a limitation of the present invention. Processor 650 receives signals from voltage detectors 610 and 620 at external signal nodes 612 and 622. FIG. 7 shows a system diagram in accordance with various embodiments of the present invention. Electronic system 700 includes processor 740, memory 750, power mode integrated circuit (PMIC) 130, power sources 710, analog circuit 720, and antenna 730. Power sources 710 may include any type of power sources, including batteries, power supplies, charging circuits, or the like. In some embodiments, power sources 710 includes main battery 120 and backup battery 110 (FIG. 1). PMIC 130 is described above with reference to FIG. 1. Processor 740 may be any type of processor that includes an ability to detect whether power supplies have ramped up using timers or voltage detectors. For example, in some embodiments, processor 740 corresponds to processor 140 (FIG. 1), and in other embodiments, processor 740 corresponds to processor 650 (FIG. 6). Memory 750 may be any type of memory accessible by processor 740. In some embodiments memory 750 may be part of processor 740. For example, memory 750 may be a cache memory within processor 740, or a non-volatile memory within processor 740. Example systems represented by FIG. 7 include cellular phones, personal digital assistants, wireless local area network interfaces, or any other system that include a processor and an antenna. Many other systems uses exist for processor 740, PMIC 130, and the various power supply detection mechanisms herein described. For example, processor 740 may be used in a desktop computer, a network bridge or router, or any other system without an antenna. Analog circuit 720 communicates with antenna 730 and processor 740. In some embodiments, analog circuit 720 includes a physical interface (PHY) corresponding to a communications protocol. For example, analog circuit 720 may include modulators, demodulators, mixers, frequency synthesizers, low noise amplifiers, power amplifiers, and the like. In some embodiments, analog circuit 720 may include a heterodyne receiver, and in other embodiments, analog circuit 720 may include a direct conversion receiver. In some embodiments, analog circuit 720 may include multiple receivers. For example, in embodiments with multiple antennas 730, each antenna may be coupled to a corresponding receiver. In operation, analog circuit 720 receives communications signals from antenna 730, and provides signals to processor 740. Further, processor 740 may provide signals to analog circuit 720, which operates on the signals and then transmits them to antenna 730. In some embodiments, processor 740 includes circuitry or performs methods to implement error detection/correction, interleaving, coding/decoding, or the like. Also in some embodiments, processor 740 may implement all or a portion of a media access control (MAC) layer of a communications protocol. In some embodiments, a MAC layer implementation may be distributed between processor 740 and digital circuitry (not shown) external to processor 740. Analog circuit 720 may be adapted to receive and demodulate signals of various formats and at various frequencies. For example, analog circuit 720 may be adapted to receive time domain multiple access (TDMA) signals, code domain multiple access (CDMA) signals, global system for mobile communications (GSM) signals, orthogonal frequency division multiplexing (OFDM) signals, multiple-input-multiple-output (MIMO) signals, spatial-division multiple access (SDMA) signals, or any other type of communications signals. The present invention is not limited in this regard. Antenna 730 may include one or more antennas. For example, antenna 730 may include a single directional antenna or an omni-directional antenna. As used herein, the term omni-directional antenna refers to any antenna having a substantially uniform pattern in at least one plane. For example, in some embodiments, antenna 730 may include a single omni-directional antenna such as a dipole antenna, or a quarter wave antenna. Also for example, in some embodiments, antenna 730 may include a single directional antenna such as a parabolic dish antenna or a Yagi antenna. In still further embodiments, antenna 730 may include multiple physical antennas. For example, in some embodiments, multiple antennas are utilized to support multiple-input-multiple-output (MIMO) processing or spatial-division multiple access (SDMA) processing. Although the various elements of system 700 are shown separate in FIG. 7, embodiments exist that combine the circuitry of processor 740, memory 750, PMIC 130 and analog circuit 720 in a single integrated circuit. In some embodiments, the various elements of system 700 may be separately packaged and mounted on a common circuit board. In other embodiments, the various elements are separate integrated circuit dice packaged together, such as in a multi-chip module, and in still further embodiments, various elements are on the same integrated circuit die. Processors, state machines, registers, and other embodiments of the present invention can be implemented in many ways. In some embodiments, they are implemented in integrated circuits. In some embodiments, design descriptions of the various embodiments of the present invention are included in libraries that enable designers to include them in custom or semi-custom designs. For example, any of the disclosed embodiments can be implemented in a synthesizable hardware design language, such as VHDL or Verilog, and distributed to designers for inclusion in standard cell designs, gate arrays, or the like. Likewise, any embodiment of the present invention can also be represented as a hard macro targeted to a specific manufacturing process. For example, register 144 may be represented as polygons assigned to layers of an integrated circuit. Although the present invention has been described in conjunction with certain embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art readily understand. Such modifications and variations are considered to be within the scope of the invention and the appended claims.
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<SOH> BACKGROUND <EOH>Processors typically receive power to operate when included in a system. The power may be received directly from one or more batteries, or from a power management integrated circuit or system, or the like. When waking from a reduced power mode, it may take time for power supply voltages to stabilize, or to “ramp up.” For example, a processor may be in a sleep mode in which one or more power supply voltages may not be provided to the processor. When exiting the sleep mode, it may take time for the power supply voltages to reach a sufficient value for the processor to operate correctly.
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<SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>FIG. 1 shows an electronic system in accordance with various embodiments of the present invention; FIG. 2 shows a register; FIGS. 3 and 4 show state machine diagrams; FIG. 5 shows a flowchart in accordance with various embodiments of the present invention; and FIGS. 6 and 7 show electronic systems in accordance with various embodiments of the present invention. detailed-description description="Detailed Description" end="lead"?
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20040630
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20071127
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20060105
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60877.0
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G06F126
| 1
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SURYAWANSHI, SURESH
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POWER SUPPLY DETECTION METHOD, APPARATUS, AND SYSTEM
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UNDISCOUNTED
| 0
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ACCEPTED
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G06F
| 2,004
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10,880,815
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ACCEPTED
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Method of operating a navigation system using images
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A method of operating a navigation system comprises providing an image of a geographic area through which a portion of a route between an origin and destination passes. The image is an approximate 360-degree image. The method provides a guidance information overlay on the image. The guidance information overlay may be a route highlight, a maneuver arrow, an indication of a path that has been traveled, an identification of a main route and an alternative route, and a label.
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1. A method of operating a navigation system comprising: providing an image of a geographic area through which a portion of a route between an origin and destination passes; wherein said image is an approximate 360-degree image. 2. The method of claim 1 further comprising: providing a guidance information overlay on the image. 3. The method of claim 2, wherein the guidance information overlay is a route highlight. 4. The method of claim 2 wherein the guidance information overlay indicates a path that has been traveled. 5. The method of claim 2 wherein the guidance information overlay identifies a main route and at least one alternative route. 6. The method of claim 5 wherein the guidance information overlay includes a symbol indicating a feature of one of said routes. 7. The method of claim 2 wherein the guidance information overlay is a maneuver arrow. 8. The method of claim 2 wherein the guidance information overlay is a label identifying a point of interest. 9. The method of claim 2 wherein the guidance information overlay is a label identifying a direction in the image. 10. The method of claim 2 wherein the guidance information overlay is a route highlight or a maneuver arrow and a label identifying a point of interest along the route. 11. The method of claim 1 further comprising: providing at least one navigation instruction indicating how to follow said portion of said route. 12. A method of operating a navigation system comprising: providing an image of a geographic area corresponding to a portion of a route between an origin and a destination; overlaying a route highlight or a maneuver arrow on said image indicating how to follow said solution route; and overlaying a label on said image identifying a point of interest in said geographic area along said solution route. 13. A method of operating a navigation system comprising: providing an image of a geographic area; overlaying a next route highlight on said image identifying a path to be traveled; and overlaying a past route highlight on said image identifying a path already traveled. 14. A method of operating a navigation system comprising: providing an image of a geographic area; overlaying a first route highlight in said image identifying a path available for traveling to a destination; and overlaying a second route highlight in said image identifying an alternative path available for traveling to said destination. 15. The method of claim 14 wherein one of said route highlights includes a symbol indicating a feature of said corresponding path. 16. The method of claim 14 wherein said image is a single view photographic image. 17. A navigation system comprising: a route guidance application capable of providing a series of images of a geographic region, said series of images depicting a continuous visual representation of a route between an origin and a destination, each of said images include a guidance information overlay. 18. The navigation system of claim 17, wherein the images are single view images. 19. A method of operating a navigation system comprising: providing an image of a geographic region; overlaying said image with labels identifying a plurality of locations in the image; and enabling a user of said navigation system to enter one of said locations; and providing a navigation feature for said entered location. 20. The method of claim 19 wherein the image is a single-view photograph. 21. The method of claim 19 wherein the image is a panoramic photograph. 22. The method of claim 19 wherein the locations are points of interest. 23. The method of claim 19 wherein said navigation feature is calculation of a route to said entered location. 24. The method of claim 19 wherein said navigation feature is route guidance to said entered location. 25. The method of claim 19 wherein the navigation feature is information about said entered location.
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REFERENCE TO RELATED APPLICATIONS The present application is related to the co-pending application entitled “METHOD OF COLLECTING INFORMATION FOR A GEOGRAPHIC DATABASE FOR USE WITH A NAVIGATION SYSTEM” filed on the same date herewith, Attorney Docket No. N0181US, the entire disclosure of which is incorporated by reference herein. The present application is related to the co-pending application entitled “METHOD OF COLLECTING INFORMATION FOR A GEOGRAPHIC DATABASE FOR USE WITH A NAVIGATION SYSTEM” filed on the same date herewith, Attorney Docket No. N0182US, the entire disclosure of which is incorporated by reference herein. The present application is related to the co-pending application entitled “METHOD OF OPERATING A NAVIGATION SYSTEM” filed on the same date herewith, Attorney Docket No. N0183US, the entire disclosure of which is incorporated by reference herein. The present application is related to the co-pending application entitled “METHOD OF COLLECTING INFORMATION FOR A GEOGRAPHIC DATABASE FOR USE WITH A NAVIGATION SYSTEM” filed on the same date herewith, Attorney Docket No. N0192US, the entire disclosure of which is incorporated by reference herein. The present application is related to the co-pending application entitled “METHOD OF COLLECTING INFORMATION FOR A GEOGRAPHIC DATABASE FOR USE WITH A NAVIGATION SYSTEM” filed on the same date herewith, Attorney Docket No. N0194US, the entire disclosure of which is incorporated by reference herein. BACKGROUND OF THE INVENTION The present invention relates to a method and system for providing navigation features and functions, and more particularly to a method and system for collecting images and providing navigation features using the images. Vehicle navigation systems are available that provide end users with various navigation-related functions and features. For example, some navigation systems are able to determine an optimum route to travel along a road network from an origin location to a destination location in a geographic region. Using input from the end user, and optionally from equipment that can determine the end user's location (such as a GPS system), the navigation system can examine various potential routes between the origin and destination locations to determine the optimum route. The navigation system may then provide the end user with information about the optimum route in the form of guidance that identifies the driving maneuvers for the end user to travel from the origin to the destination location. The guidance may take the form of visual and/or audio instructions that are provided along the way as the end user is traveling the route. Some navigation systems are able to show detailed maps on displays outlining the route, the types of maneuvers to be taken at various locations along the route, locations of certain types of features, and so on. In order to provide these and other navigation-related functions and features, navigation systems use geographic data. The geographic data may be in the form of one or more geographic databases that include data representing physical features in the geographic region. The geographic database includes information about the represented geographic features, such as the positions of the roads, speed limits along portions of roads, address ranges along the road portions, turn restrictions at intersections of roads, direction restrictions, such as one-way streets, and so on. Additionally, the geographic data may include points of interest, such as restaurants, hotels, airports, gas stations, stadiums, police stations, and so on. Although navigation systems provide many important features, there continues to be room for new features and improvements. One area in which there is room for improvement relates to providing improved guidance for following the route. In some situations, additional guidance and orientation information would be helpful when following the route. For example, some areas may be difficult for a user of a navigation system 100 to traverse because of the many road segments intersecting in the area and the many different turn options available to travel. Additionally, pedestrians may find additional guidance and orientation information helpful when traversing a route because pedestrians have a greater degree of freedom of motion and may become more frequently confused as to their orientation to destination. Accordingly, it would be beneficial to have a way to collect and provide images that may be used to provide improved navigation-related functions and features. SUMMARY OF THE INVENTION A method and system of operating a navigation system is described in the embodiments disclosed herein. The method provides an image of a geographic area through which a portion of a route between an origin and destination passes. The image may be an approximate 360-degree image. The image may include a guidance information overlay on the image, such as a route highlight, a maneuver arrow, an indication of a path that has been traveled, a main route and alternative route, and a label. The images with the guidance information overlays may orient and provide guidance to the user of the navigation system. In another embodiment, the method of operating a navigation system provides an image of a geographic region and overlays the image with labels identifying locations in the image. The method enables a user of the navigation system to enter one of the locations and provides a navigation feature for the entered location. The image may be a single-view photograph or a panoramic photograph. The locations identified with labels may be points of interests. BRIEF DESCRIPTION OF THE DRAWINGS An exemplary embodiment of the present invention is described herein with reference to the drawings, in which: FIG. 1 is a block diagram of a navigation system, according to an exemplary embodiment; FIG. 2 illustrates a map of a geographic region; FIG. 3 is a block diagram of a geographic database included in the navigation system depicted in FIG. 1, according to an exemplary embodiment; FIG. 4 is a block diagram of road segment data records and node data records contained in the geographic database depicted in FIG. 3, according to an exemplary embodiment; FIG. 5 is a block diagram of pedestrian segment data records and orientation node data records contained in the geographic database depicted in FIG. 3, according to an exemplary embodiment; FIG. 6 is a 360-degree panoramic image of an intersection; FIG. 7 is a flow chart for collecting image data, according to an exemplary embodiment; FIG. 8 is a flow chart for coding the image for guidance information overlays; FIG. 9 is an image depicting coding for guidance information overlays; FIG. 10 is a block diagram of image data records, according to an exemplary embodiment; FIG. 11 is a flow chart for using images to provide guidance, according to an exemplary embodiment; FIG. 12 is a 360-degree panoramic image depicting the use of guidance information overlays, according to an exemplary embodiment; FIG. 13 is a pictorial representation of overlay dot size used in the guidance information overlays, according to an exemplary embodiment; FIG. 14 is an image depicting the use of the guidance information overlays, according to another exemplary embodiment; FIG. 15 is an image depicting the use of the guidance information overlays, according to another exemplary embodiment; FIG. 16 is a screen shot depicting the use image with guidance information overlay as provided by the navigation system depicted in FIG. 1, according to an exemplary embodiment; FIG. 17 is a screen shot of an image with guidance information overlay and a textual guidance message provided by the navigation system depicted in FIG. 1, according to an exemplary embodiment; FIG. 18A is a screen shot of an image with guidance information overlay and a touch-screen icon for requesting a guidance message as provided by the navigation system depicted in FIG. 1, according to an exemplary embodiment; FIG. 18B is a screen shot of a guidance message and a touch-screen icon for requesting an image with guidance information overlay as provided by the navigation system depicted in FIG. 1, according to an exemplary embodiment; and FIG. 19 is an image including label overlays provided by the navigation system depicted in FIG. 1, according to an exemplary embodiment. DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS I. Navigation System FIG. 1 is a block diagram of a navigation system 100 associated with a computing platform 102, such as a personal digital assistant (PDA), mobile telephone or any computer, according to an exemplary embodiment. The navigation system 100 is a combination of hardware and software components. In one embodiment, the navigation system 100 includes a processor 104, a drive 106 connected to the processor 104, and a non-volatile memory storage device 108 for storing navigation application software programs 110 and possibly other information. The navigation system 100 also includes a positioning system 112. The positioning system 112 may utilize GPS-type technology, a dead reckoning-type system, or combinations of these or other systems, all of which are known in the art. The positioning system 112 may include suitable sensing devices that measure the traveling distance speed, direction, orientation and so on. The positioning system 112 may also include a GPS system. The positioning system 112 outputs a signal to the processor 104. The navigation application software programs 110 that run on the processor 104 use the signal from the positioning system 112 to determine the location, direction, orientation, etc., of the computing platform 102. The navigation system 100 also includes a user interface 114 that allows the end user to input information into the navigation system 100 and obtain information from the navigation system 100. The input information may include a request for navigation features and functions of the navigation system 100. In one embodiment, information from the navigation system 100 is provided on a display screen of the user interface 114. To provide navigation features and functions, the navigation system 100 uses a geographic database 116 stored on a storage medium 118. In one embodiment, the storage medium 118 is installed in the drive 106 so that the geographic database 116 can be read and used by the navigation system 100. In one embodiment, the geographic database 116 may be a geographic database published by NAVTEQ North America, LLC of Chicago, Ill. The storage medium 118 and the geographic database 116 do not have to be physically provided at the location of the navigation system 100. In alternative embodiments, the storage medium 118, upon which some or the entire geographic database 116 is stored, may be located remotely from the rest of the navigation system 100 and portions of the geographic data provided via a communications system 120, as needed. In one exemplary type of system, the navigation application software programs 110 load from the non-volatile memory storage device 108 into a random access memory (RAM) 122 associated with the processor 104. The processor 104 also receives input from the user interface 114. The navigation system 100 uses the geographic database 116 stored on the storage medium 118, possibly in conjunction with the outputs from the positioning system 112 and the communications system 120, to provide various navigation features and functions. The navigation application software programs 110 may include separate applications (or subprograms) that provide the various navigation-related features and functions. The navigation functions and features may include route calculation 124 (wherein a route from an origin to a destination is determined), route guidance 126 (wherein detailed directions are provided for reaching a desired destination), map display 128, and positioning 130 (e.g., map matching). Other functions and programming 132 may be included in the navigation system 100. The navigation application software programs 110 may be written in a suitable computer programming language such as C, although other programming languages, such as C++ or Java, are also suitable. All of the components described above may be conventional (or other than conventional) and the manufacture and use of these components are known to those of skill in the art. II. Geographic Database In order to provide navigation-related features and functions to the end user, the navigation system 100 uses the geographic database 116. The geographic database 116 includes information about one or more geographic regions. FIG. 2 illustrates a map 200 of a geographic region 202. The geographic region 202 may correspond to a metropolitan or rural area, a state, a country, or combinations thereof, or any other area. Located in the geographic region 202 are physical geographic features, such as roads, points of interest (including businesses, municipal facilities, etc.), lakes, rivers, railroads, municipalities, etc. FIG. 2 also includes an enlarged map 204 of a portion 206 of the geographic region 202. The enlarged map 204 illustrates part of a road network 208 in the geographic region 202. The road network 208 includes, among other things, roads and intersections located in the geographic region 202. As shown in the portion 206, each road in the geographic region 202 is composed of one or more road segments 210. A road segment 210 represents a portion of the road. Each road segment 210 is shown to have associated with it two nodes 212; one node represents the point at one end of the road segment and the other node represents the point at the other end of the road segment. The node 212 at either end of a road segment 210 may correspond to a location at which the road meets another road, i.e., an intersection, or where the road dead-ends. Also included in the portion 206 of the geographic region 202 are paths or a path network (not shown) that may be traversed by pedestrians, such as in a park or plaza. Referring to FIG. 3, the geographic database 116 contains data 302 that represents some of the physical geographic features in the geographic region 202 depicted in FIG. 2. The data 302 contained in the geographic database 116 includes data that represent the road network 208. In the embodiment of FIG. 3, the geographic database 116 that represents the geographic region 202 contains at least one road segment database record 304 (also referred to as “entity” or “entry”) for each road segment 210 in the geographic region 202. The geographic database 116 that represents the geographic region 202 also includes a node database record 306 (or “entity” or “entry”) for each node 212 in the geographic region 202. The terms “nodes” and “segments” represent only one terminology for describing these physical geographic features, and other terminology for describing these features is intended to be encompassed within the scope of these concepts. In one embodiment, the geographic database 116 that represents the geographic region 202 also contains at least one pedestrian segment database record 308 for each pedestrian segment in the geographic region 202 and orientation node database record 310 for each orientation node in the geographic region 202. Pedestrian segments and orientation nodes are associated with paths that may be traversed by pedestrians, such as in the park or plaza. A more detailed description of pedestrian segments and orientation nodes may be found in the co-pending application entitled “METHOD OF COLLECTING INFORMATION FOR A GEOGRAPHIC DATABASE FOR USE WITH A NAVIGATION SYSTEM” filed on the same date herewith, Attorney Docket No. N0181US, the entire disclosure of which is incorporated by reference herein. The geographic database 116 may also include other kinds of data 312. The other kinds of data 312 may represent other kinds of geographic features or anything else. The other kinds of data may include point of interest data. For example, the point of interest data may include point of interest records comprising a type (e.g., the type of point of interest, such as restaurant, hotel, city hall, police station, historical marker, ATM, golf course, etc.), location of the point of interest, a phone number, hours of operation, etc. The geographic database 116 also includes indexes 314. The indexes 314 may include various types of indexes that relate the different types of data to each other or that relate to other aspects of the data contained in the geographic database 116. For example, the indexes 314 may relate the nodes in the node data records 306 with the end points of a road segment in the road segment data records 304. As another example, the indexes 314 may relate point of interest data in the other data records 312 with a road segment in the segment data records 304. FIG. 4 shows some of the components of a road segment data record 304 contained in the geographic database 116. The road segment data record 304 includes a segment ID 304(1) by which the data record can be identified in the geographic database 116. Each road segment data record 304 has associated with it information (such as “attributes”, “fields”, etc.) that describes features of the represented road segment. The road segment data record 304 may include data 304(2) that indicate the restrictions, if any, on the direction of vehicular travel permitted on the represented road segment. The road segment data record 304 includes data 304(3) that indicate a speed limit or speed category (i.e., the maximum permitted vehicular speed of travel) on the represented road segment. The road segment data record 304 may also include data 304(4) indicating whether the represented road segment is part of a controlled access road (such as an expressway), a ramp to a controlled access road, a bridge, a tunnel, a toll road, a ferry, and so on. The road segment data record 304 also includes data 304(6) providing the geographic coordinates (e.g., the latitude and longitude) of the end points of the represented road segment. In one embodiment, the data 304(6) are references to the node data records 306 that represent the nodes corresponding to the end points of the represented road segment. The road segment data record 304 may also include or be associated with other data 304(7) that refer to various other attributes of the represented road segment. The various attributes associated with a road segment may be included in a single road segment record, or may be included in more than one type of record that cross-references to each other. For example, the road segment data record 304 may include data identifying what turn restrictions exist at each of the nodes which correspond to intersections at the ends of the road portion represented by the road segment, the name or names by which the represented road segment is known, the street address ranges along the represented road segment, and so on. FIG. 4 also shows some of the components of a node data record 306 contained in the geographic database 116. Each of the node data records 306 may have associated information (such as “attributes”, “fields”, etc.) that allows identification of the road segment(s) that connect to it and/or it's geographic position (e.g., its latitude and longitude coordinates). For the embodiment shown in FIG. 4, the node data records 306(1) and 306(2) include the latitude and longitude coordinates 306(1)(1) and 306(2)(1) for their node. The node data records 306(1) and 306(2) may also include other data 306(1)(3) and 306(2)(3) that refer to various other attributes of the nodes. FIG. 5 shows some of the components of a pedestrian segment data record 308 contained in the geographic database 116. The pedestrian segment data record 308 includes a segment ID 308(1) by which the data record can be identified in the geographic database 116. Each pedestrian segment data record 308 has associated with it information (such as “attributes”, “fields”, etc.) that describes features of the represented pedestrian segment. The pedestrian segment data record 308 may include data 308(2) that indicate a type of pedestrian segment, such as virtual pedestrian path, paved pedestrian path, unpaved pedestrian path, sidewalk, alley, indoor path. The pedestrian segment data record 308 includes data 308(3) that indicate a phrase ID and data indicating a segment name 308(4) which together provide a text description of the pedestrian segment. The data indicating the phrase ID provides a predetermined phrase that accompanies the segment name to describe the pedestrian segment. The pedestrian segment data record 308 may also include applicable direction data 308(5) indicating whether direction of travel on the pedestrian segment affects how the pedestrian segment should be described, and if so, the direction of travel associated with the above data. The pedestrian segment data record 308 also includes data 308(7) relating to the end points of the represented pedestrian segment. The endpoint data includes data 308(7) include references 308(7)(1) to the orientation node data records 310 that represent the orientation nodes corresponding to the end points of the represented pedestrian segment. The pedestrian segment data record 308 may also include or be associated with other data 308(8) that refer to various other attributes of the represented pedestrian segment. The various attributes associated with a pedestrian segment may be included in a single pedestrian segment record, or may be included in more than one type of record that cross-references to each other. FIG. 5 also shows some of the components of an orientation node data record 310 contained in the geographic database 116. Each orientation node data record 310(1) and 310(2) include a node ID 310(1)(1) and 310(2)(1) by which the data record can be identified in the geographic database 116. Each of the orientation node data records 310 may have associated information (such as “attributes”, “fields”, etc.) that allows identification of the pedestrian segment(s) that connect to it and/or it's geographic position (e.g., its latitude and longitude coordinates). For the embodiment shown in FIG. 5, the orientation node data records 310(1) and 310(2) include the latitude and longitude coordinates 310(1)(2) and 310(2)(2) for their node. Each orientation node data record also includes data indicating an orientation node name 310(1)(3) and 310(2)(3). Each orientation node data record also includes connection data 310(1)(5) and 310(2)(5) indicating connection, if any, to the road network. In one embodiment, the connection data 310(1)(5) and 310(2)(5) are references to the road segment data records 304 and/or road network node data records 306 that represent the road segments and nodes that connect with the orientation node. The node data records 310(1) and 310(2) may also include other data 310(1)(6) and 310(2)(6) that refer to various other attributes of the nodes. III. Collecting Images Referring to FIG. 1, the navigation system 100 provides various navigation-related features and functions including route guidance 126. Route guidance 126 provides a user of the navigation system 100 with detailed directions for reaching a desired destination. In one embodiment, the directions include maneuver instructions at specified intersections. Some areas within the geographic region 202 may be difficult to traverse even with the detailed directions from the conventional route guidance feature 126. FIG. 6 is a 360-degree panoramic image 600 of Piccadilly Circus in London, England. Piccadilly Circus is an example of an area that may be difficult for a user of a navigation system 100 to traverse because of the many road segments intersecting in the area and the many different turn options available to travel. Additionally, a pedestrian may have difficultly traversing some areas, such as Piccadilly Circus, because the pedestrian has a greater freedom of movement as a vehicle. The pedestrian does not have direction restrictions as a vehicle; the pedestrian can walk down a one-way street in both directions. Moreover, the pedestrian may become more frequently confused as to direction of travel and orientation. To allow the navigation system 100 to provide improved route guidance, a geographic database developer collects image data of road segments, road nodes or intersections, pedestrian segments, orientation nodes and any other geographic feature. In one embodiment, a geographic researcher travels the geographic region to collect image data. In another embodiment, the geographic researcher obtains image data from other sources, such as an image repository. FIG. 7 is a flow chart for collecting image data in the geographic region 202, according to an exemplary embodiment. At step 700, the researcher identifies an area of the geographic region appropriate for collecting image data. In one embodiment, the area appropriate for collecting image data is a confusing intersection. In another embodiment, the areas appropriate for collecting image data are decision points along a road or pedestrian network at which the user of the navigation system 100 has an option of turning. In other embodiments, the area appropriate for collecting image data may be any intersection, road segment, pedestrian segment, orientation node, scenic view, point of interest, such as a business or facility, or any other geographic feature. In another embodiment, the researcher collects a series of images along the road and/or pedestrian segments to enable a user to obtain a continuous visual representation of a route or a visual representation of a significant portion of the route. At step 702, the researcher captures a photographic image of the area. The certain geographic areas, images may be taken during the day and at night Additionally, it may be more desirable to capture the image when the weather is dry to obtain clear photographs. Further, the photographs may be taken when the area is empty, so that cars and pedestrians do not obscure the view. In one embodiment, the geographic researcher uses a digital camera, a video camera, a film camera or any other device to obtain the images. The images may be a single view, 180-degree view, a 360-degree panoramic view, such as the 360-degree panoramic image 600 of FIG. 6, or any other type of image. In one embodiment, the 360-degree panoramic image may be taken by using a camera designed to take 360-degree panoramic photographs. For example, the camera may have a fisheye/180/360 degree camera lens. Alternatively, the 360-degree panoramic image may be stitched together from a series of single view images showing a section of the 360-degree view as known to one skilled in the art. After capturing the images, the images are digitally stored in a memory device. At step 704, the researcher records a location associated with the image. In one embodiment, the researcher records a position of the location from which the image was captured. In another embodiment, the researcher records the position and/or name of a geographic feature within the captured image, such as an intersection, road segment, building or any other feature. In a further embodiment, the researcher records the position and/or name of a geographic feature proximate the location from which the image was captured. The research may use a positioning system to determine the location. The positioning system may be the same or a different system as the positioning system 112 depicted in FIG. 1. The positioning system may utilize GPS-type technology, a dead reckoning-type system, or combinations of these or other systems, all of which are known in the art. The positioning system may include suitable sensing devices that measure the traveling distance speed, direction, and so on, of the system. The positioning system may also include appropriate technology to obtain a GPS signal, in a manner that is known in the art. The positioning system may provide as an output the latitude and longitude of the location at which the image was captured. In addition, maps and aerial images of the area may be used to determine the position associated with the captured image. The researcher may record the position information and any other information associated with the image using any data collection method, such as handwriting, voice recording and data entry into a user device. At step 706, the researcher records a direction associated with the captured image. In one embodiment, the direction associated with the captured image is a direction in which the camera was facing when the image was captured. The researcher may determine the direction of the view using general knowledge, a compass, the positioning system or any other method of determining direction. In another embodiment, the direction associated with the image references a geographic feature captured in the image, such as along a road segment or at a building. At step 708, the image is cross-referenced with at least one geographic feature. In one embodiment, the image is cross-referenced with a road-network node and/or a pedestrian orientation node. In another embodiment, the image is associated with a road segment, pedestrians segment and/or a position along a road segment or pedestrian segment. In a further embodiment, the image is associated with a point of interest, such as a building, business, restaurant, hotel, city hall, police station, historical marker, ATM or any other type of point of interest or any other geographic feature. The researcher may cross-reference the image with at least one of the geographic features by recording the geographic feature when capturing the image. Alternatively, the location, such as latitude and longitude coordinates, may be geo-coded to identify a geographic feature in the geographic database 116 in proximity to the location associated with the image. At block 710, the image is coded for guidance information overlays, such as a path, a specific maneuver, a direction of travel, a label or any other overlay. FIG. 8 below describes coding the image for guidance information overlays according to one embodiment. At step 712, the image and associated data are stored in the geographic database 116 as will be described in more detail below. In alternative embodiments, the steps for collecting image data are performed in a different order than presented in FIG. 7. Additionally, a geographic researcher traveling the geographic region may perform some of the above steps of FIG. 7, while another geographic researcher at a central base station may perform the remaining steps of FIG. 7. FIG. 8 is a flow chart for coding the image for guidance information overlays according to one embodiment. Some of the steps of FIG. 8 will be illustrated with the image 900 of FIG. 9. At step 800, the researcher identifies a control point 902 for the image 900. In one embodiment, the control point 902 indicates a direction, such as north, in the image 900. In another embodiment, the control point 902 indicates a location at which the image was captured. At step 802, the researcher determines a line-of-sight associated with the captured image. The line-of-sight associated with the captured image is a distance that can be seen in the image 900, such as 20 meters. The line-of-sight may be calculated using standard Geographic Information Systems (GIS) software. Alternatively, the line-of-sight calculation may be performed using Digital Elevation Models (DEM). The line-of-sight may be limited by obstructions in the view, such as buildings and trees. At step 804, the researcher identifies geographic features in the image 900. In one embodiment, road segments, nodes or intersections, pedestrian segments, pedestrian orientation nodes are identified. Additionally, any feature present in the image may be identified including lakes, rivers, railroads, municipalities, points of interest, such as buildings, businesses, restaurants, stores, hotels, municipal facilities, historical markers, ATMs, golf courses, water fountains, statues, bike racks, etc. For the image 900 in FIG. 9, the researcher would identify the paved pedestrian segments 904, pedestrian orientation nodes 906 at the intersections of the pedestrian segments and a statue 908. At step 806, the researcher creates guide points 910 and label points 912 on the image 900. The guide points 910 are located at positions on the image 900 that correspond to locations at which guidance type information may be overlaid on the image 900. For example, guide points 910 may be located to correspond with road segments, nodes or intersections of road segments, pedestrian segments 904, pedestrian orientation nodes 906 and/or decision points in the image 900. In one embodiment, the guide points 910 are located at positions on the image 900 suitable for guidance information overlays, such as route highlights and guidance arrows. In one embodiment, guide points are placed at the endpoints of the road or pedestrian segments and at intermediate locations to provide shape points for the respective segment. In one embodiment, guide points 910 are placed at the visual end of the segments in the image 900, and the line-of-sight calculation may be used to determine placement of the guide points. For example, if a tree obstructs a view of a segment, one guide point is positioned as an endpoint just prior to the tree, and if the segment is visible after the tree, another guide point is placed as an endpoint after the tree. In another embodiment, the guide points on either side of the tree may specify that any route highlight between these guide points should be transparent so as not to highlight over the tree in the image. The label points 912 are located at positions on the image 900 that correspond to locations at which label type information may be overlaid on the image 900. For example, label points may be located to correspond with points of interest, such as the statue 908. In another embodiment, label points may be located to correspond with locations on the image 900 where advertisements, addresses, direction (north), icons, place names or any other information may be overlaid on the image 900. In one embodiment, the researcher or a technician manually identifies the locations of the guide points and label points on the image. The researcher or technician digitizes the guide points and label points onto the image. The guide points 910 and label points 912 on the image 900 provide locations for the guidance information overlays. For example, if the geographic overlay is a route highlight to direct a user of the navigation system 100 to follow a road segment, a route highlight may be drawn connecting the guide points associated road segment in the image. In one embodiment, the pixels of the image corresponding to the identified locations for the guide points and label points are coded to facilitate placement of the overlays. An image is composed of numerous pixels. Each pixel may include one or more bits of overlay information as is known in the art. For example, the pixel value may have one bit of overlay information to support the use of overlays. The one bit of overlay information may be used as a toggle bit. Once the toggle bit is set, the pixel is ignored so that an overlay, such as the guidance information overlay, can be placed on the image. In another embodiment, the pixel value may have eight bits of overlay information, which may allow for variations in transparency between the overlay and the bottom image. The coding of the overlay pixels for the guide points and label points in the image enable the navigation system 100 to dynamically place several different guidance information overlays, such as a route highlight, maneuver arrows, direction or labels, on the image. At step 808, the guide points and label points are associated with geographic features and/or text labels. For example, the guide points that correspond with a road segment are associated with the respective road segment ID; the guide points that correspond to a node is associated with the respective node ID; the guide points that correspond with a pedestrian segment are associated with the respective pedestrian segment ID; the guide point that correspond to an orientation node is associated with the orientation node ID; the guide point or label point that correspond to a point of interest is associated with the respective point of interest. Furthermore, label points are associated with corresponding text. The image data, guide point and label point information, associated features and labels are then stored in the geographic database as discussed in greater detail below. In another embodiment, the steps 804, 806 and 808 are performed by overlaying vector data representing the geometry of the geographic area onto the image. Based on the distance visible in the image from the line of sight determination and the location and direction from which the image was captured, vector data representing the geometry of the geographic area visible in the image is obtained from the geographic database 116. For example, if the line of sight for the image is 20 meters, a vector data clip corresponding to the 20 meters area visible in the image is obtained from the geographic database 116. Because the image is captured at a height above ground surface, the image provides a birds-eye view of the geographic area. To accommodate the birds-eye perspective, the vector data clip of the geographic area in the image is obliquely projected onto the image. Additionally, the vector data clip may be appropriately scaled so the overlay of the vector data matches the features of the image. The overlaid vector data comprising vector points at nodes and shape points along segments align with their respective intersections and paths in the image. The vector data clip includes segment IDs and node IDs enabling identification of the paths and intersections visible in the image. Additionally, the image and associated vector data clip are stored in the geographic database. IV. Geographic Database With Image Data The image data collected as described above in conjunction with FIG. 7 is included in the geographic database 116 that represents some of the physical geographic features in the geographic region 202. In the embodiment of FIG. 4, the road segment data record 304 of the geographic database 116 contains an image data record 304(5), and the node data record 306(1) and 306(2) of the geographic database 116 also contains an image data record 306(1)(2) and 306(2)(2). In the embodiment of FIG. 5, the pedestrian segment data record 308 of the geographic database 116 contains an image data record 308(5), and the orientation node data record 310(1) and 310(2) of the geographic database 116 also contains an image data record 310(1)(4) and 310(2)(4). In one embodiment, the image data associated with the road segment data record 304, the node data record 306, the pedestrian segment data record 308 and/or the orientation node data record 310 are references to image data records 1000 as described in conjunction with FIG. 10. Additionally, the road segment data record 304, the node data record 306, the pedestrian segment data record 308 and/or the orientation node data record 310 may each be associated with several image data records 1000. For example, a node data record 306 representing an intersection of two roads may be associated with four image data records 1000. FIG. 10 shows some of the components of an image data record 1000 contained in the geographic database 116. The image data record 1000 includes an image ID 1000(1) by which the data record can be identified in the geographic database 116. Each image data record 1000 has associated with it information (such as “attributes”, “fields”, etc.) that describes features of the represented image. The image data record 1000 may include data 1000(2) or a feature code that indicates a type of geographic feature captured in the respective image, such as a road segment, road intersection, pedestrian segment, orientation node, point of interest, scenic view or any geographic feature of the geographic region. The image data record 1000 includes data 1000(3) that indicate a location associated with the image, such as the longitude and latitude coordinates of the location. The image data record 1000 also includes data 1000(4) that indicates a direction associated with the image, such as a direction associated with a control point in the image. The image data record 1000 includes data 1000(5) enabling the image to be displayed. Furthermore, the image data record 1000 may include overlay data 1000(6) providing data to allow the navigation system 100 to create guidance information overlays on the image. In one embodiment, the overlay data 1000(6) identifies overlay pixels corresponding to guide points and label points of the image. Additionally, the overlay data 1000(6) identifies the overlay pixels that correspond to geographic features, such as road segments, pedestrian segments, nodes and orientation nodes to allow route highlights and maneuver arrows to be overlaid on the image at locations corresponding to the geographic features. Furthermore, the overlay data 1000(6) may identify overlay pixels corresponding to points of interest or other items in the image suitable for guidance information overlays, such as text, advertising and icons. The overlay data 1000(6) may also indicate the style and information included in the guidance information overlay. By identifying the pixels in the image, guidance information overlays may be created dynamically by the navigation system 100, which may avoid having to store multiple copies of the same image. For example, the overlay may be an arrow pointing to a direction to walk, such as the arrow 602 depicted in FIG. 6. As another example, the overlay may be a route highlight comprising series of dots for the user of the navigation system 100 to follow. Any other overlay may be used, such as labels and direction indications. In an alternative embodiment, the overlay data 1000(6) may contain a plurality of established guidance information overlays, such as route highlights or maneuver arrows associated with road segments or pedestrian segments. The image data record 1000 may also data 1000(7) indicating a geographic feature ID or several geographic features associated with the image. As discussed above in conjunction with FIG. 7, the image is cross-referenced with the geographic feature(s). The associated geographic feature ID data may be a road segment ID, node ID, pedestrian segment ID, orientation node ID, point of interest ID or a reference to any other geographic feature of the geographic database 116. The image data record 1000 may also include other data 1000(8). In another embodiment, the image data record 1000 includes data providing a vector data clip (not shown) corresponding to the photo data 1000(5). V. Guidance Information Overlays on Images As discussed above in conjunction with FIG. 1, the navigation system 100 includes navigation application software programs 110 that provide the various navigation features and functions. In one embodiment, the navigation functions and features may include route calculation 124 and route guidance 126. The route calculation function 124 receives a request to calculate a route to a desired destination. The request may be in the form of an identification of a starting location and a desired destination location. The identification of these locations may include the geographic coordinates of these locations. The route calculation function may also be provided with other data or parameters, such as preferences (e.g., scenic route, handicap access, or any other preference). Given at least the identification of the starting location and the destination location, the route calculation function 124 attempts to determine one or more solution routes between the starting location and the destination location. A solution route is formed of a series of connected road and/or pedestrian segments over which the user of the navigation system 100 can travel from the starting location to the destination location. When the route calculation function 124 calculates a route, it accesses the geographic database 116 and obtains road segment data entities 304 and/or pedestrian segment data entities 308 that represent segments around and between the starting location and the destination location. The route calculation function 124 uses the information in the road and/or pedestrian segment data entities 304 and 308 to attempt to determine at least one valid solution route from the starting location to the destination location. In determining a valid solution route for the pedestrian to travel, the route calculation program 124 uses the data attributes associated with the road and/or pedestrian segment data entities to account for preferences. The route calculation function 124 may attempt to find solution routes that takes the least time to travel, that covers the least distance, or that meets some other specifiable criteria. The route calculation function 124 may use various means or algorithms in determining solution routes. Methods for route calculation are disclosed in U.S. Pat. No. 6,192,314, the entire disclosure of which is incorporated by reference herein. (The methods disclosed in the aforementioned patent represent only some of the ways that routes can be calculated and the claimed subject matter herein is not limited to any particular method of route calculation. Any suitable route calculation method now known or developed in the future may be employed.) The route calculation function 124 provides an output. In one embodiment, the output of the route calculation function 124 is in the form of an ordered list identifying a plurality of road and/or pedestrian segment data entities. The plurality of road and/or pedestrian segment data entities represent the road and/or pedestrian segments that form the continuous navigable route between the starting location and the destination that had been calculated by the route calculation function 124. The route calculation function 124 may calculate more than one solution route including alternative ordered lists of the plurality of road and/or pedestrian segments. As discussed above in conjunction with FIG. 1, the navigation system 100 includes navigation application software programs 110 that provide the navigation feature and function of route guidance 126 for the user of the navigation system 100. The route guidance function 126 provides detailed directions for reaching a desired destination. In one embodiment, the list of road and/or pedestrian segment data entities determined by the route calculation function 124 is provided to the route guidance function 126. The route guidance function 126 uses the information in the list, as well as additional information from the geographic database 116, to provide instructions to the end user to travel the route defined by the list output by the route calculation function 124. The route guidance function 126 may include functions that identify locations along the calculated route at which maneuvering instructions may be provided to the end user. The route guidance function 126 may provide the maneuvering instructions all at once, or alternatively, the route guidance function 126 may provide the maneuvering instructions one at a time as the end user is traveling. In one embodiment, each maneuvering instruction is provided separately (or in small groups of combined maneuvering instructions) in advance of when the specific maneuver is required to be taken so that the end user can prepare to make the required maneuver. The output of the route guidance function 126 is provided to the end user through a user interface 114 included on the computing platform 102. The output of the route guidance may be conveyed audibly through speech synthesis or on a visual display. Methods for providing route guidance using geographic data are disclosed in U.S. Pat. No. 6,199,013, the entire disclosure of which is incorporated herein by reference. (The methods disclosed in the aforementioned patent represent only some of the ways that route guidance can be calculated and the claimed subject matter herein is not limited to any particular method of route guidance. Any suitable route guidance method now known or developed in the future may be employed.) In order to provide maneuvering instructions at appropriate times and/or locations, the navigation system 100 uses data from the positioning system (112 in FIG. 1). The positioning system 112 determines the position of the end user (computing platform 102) as he or she is traveling. A positioning (map-matching) function 130 in the navigation programming 110 compares the user's position determined by the positioning system 112 to the positions of the road and/or pedestrian segments represented by the road and/or pedestrian segment data entities in the solution route. Using this comparison, the maneuver instructions, which are related to positions along the solution route, can be provided at appropriates times as these positions are approached. The route guidance function 126 may also provide the end user with information about the remaining distance to the destination location. The list of road and/or pedestrian segment data entities from the route calculation function 124 may also be provided to the map display function 128. The map display function 128 uses the information in the list, as well as additional information from the geographic database 116, to provide graphical maps on a display of the user interface 114. The graphical maps illustrate the areas through which the calculated route passes. The path of the calculated route may be highlighted on the displayed maps. In one embodiment, the route guidance function 126 also provides images with guidance information overlays. The images with overlays may be provided in conjunction with maneuver instructions. In an alternative embodiment, the route guidance function 126 provides an image with a guidance information overlay instead of audio or textual maneuver instructions. In another embodiment, the route guidance function 126 provides an image with a guidance information overlay at various locations along the solution route, such as at decision points. In a further embodiment, the route guidance function 126 provides a series of images with guidance information overlays to provide a continuous visual representation of the solution route. FIG. 11 is a flow chart that depicts the steps performed by the route guidance function 126 to provide an image with a guidance information overlay. At step 1100, the route guidance function 126 determines whether an image is available in the geographic database 116 corresponding to the current location and direction of the navigation system 100 as it travels along the solution route provided by the route calculation function 124. In one embodiment, the route guidance function 126 references the road segment data record 304, node data record 306, pedestrian segment data record 308 and/or orientation node data record 310 corresponding to the current location of the navigation system 100 to determine whether an image data record 1000 exists. In one embodiment, the determination includes whether an appropriate image based on the direction of travel and/or time of day is available from the reference image data record 1000. At step 1102, the route guidance function 126 determines whether to present the image to the user of the navigation system 100 via the user interface 114. In one embodiment, the navigation system 100 provides images only when requested by the user of the navigation system 100. For example, the user may request the images using the user interface 114. In another embodiment, the navigation system 100 provides images automatically at every decision point along the calculated route. At step 1104, the route guidance function 126 determines an appropriate guidance information overlay. The guidance information overlay may be a maneuver arrow, a line or plurality of dots highlighting the solution route or alternate routes, text labels, direction labels or any other information. The route guidance function 126 may obtain data from the image data record 1000 indicating the overlay pixels corresponding to the road segments, pedestrian segments, nodes and/or orientations nodes comprising the current portion of the route. Additionally, the route guidance function 126 may select appropriate guidance overlays to place at the overlay pixels. For example, if the driving direction is a right turn onto a road segment at the next intersection, the route guidance function 126 selects the guidance information overlay that provides a maneuver arrow for turning right onto the road segment on the associated image. At step 1106, the image with the guidance information overlay is created. FIGS. 6, 12-15 will be used to illustrate embodiments of the image with guidance information overlay. FIG. 6 illustrates one embodiment of the guidance information overlay of a maneuver arrow 602. The image 600 is a 360-degree panoramic photograph of a road node. The image 600 include the guidance information overlay of the maneuver arrow 602 indicating a direction of travel or turn required from the current location onto a connected road segment to follow the solution route. The 360-degree panoramic photograph 600 helps to orient the user of the navigation system 100 and may be especially helpful to a pedestrian. The guidance information overlay of the maneuver arrow 602 directs the user to turn onto an indicated road segment that the user may more readily identify by comparing the features in the image 600 to their visible surroundings. Additionally, the maneuver arrow 602 may be any color; the color may be chosen in a manner such that the user quickly notices the guidance information overlay 602. While FIG. 6 depicts a 360-degree photograph, the image may be a single-view photograph. In another embodiment, the guidance information overlay includes a label 604 indicating a visible point of interest along the calculated route. As shown in FIG. 6, the label 604 indicates a “bank” is along the solution route. In other embodiments, the label may be associated any other point of interest visible to the user from the solution route. Furthermore, the label 604 may be an icon indicating the type of point of interest, a description of the point of interest, a name of the point of interest or any other information regarding the point of interest. The label 604 provides supplemental guidance information to the user and may be used to confirm that the user is following the calculated route. Additionally, guidance information overlay may comprise labels for other points of interests or features in the image to help orientate the user. For example, the guidance information overlay may comprise a label identifying a readily visible landmark such as a communications tower. In one embodiment, the guidance information overlay is a label indicating a direction. In another embodiment, the overlay may comprise an advertisement associated with a business visible in the image 600 or a business located close to the area of the image 600. FIG. 12 illustrates another embodiment of the guidance information overlay. The image 1200 in FIG. 12 is a 360-degree photograph. The guidance information overlay is a route highlight as depicted with a plurality of dots or “bread crumbs.” A first series of dots 1202 are used depict the portion of the solution route that has been traveled and a second series of dots 1204 are used to depict the next road and/or pedestrian segment(s) of the solution route. The dots 1204 allow the user to visually identify the next portion of the route on the image 1200 and visually orient him or her in the geographic region using the image and guidance information overlay. While dots are used in FIG. 12, any route highlight may be used such as a series of arrows, a solid line 1206, a dash line or any other shape. The first and second series of dots 1202 and 1204 may be different colors to distinguish the two portions of the solution route. As seen in FIG. 12, the dots closest to the pedestrian may appear larger than the dots further away. The interval and size of the dots is described with more detail with reference to FIG. 13. FIG. 13 is a pictorial representation 1300 of guidance information overlay comprising the series of dots, according to an exemplary embodiment. Dot 1302 may indicate a location at which the image was captured. Additionally, the dot 1302 may be used to represent the location of the user in the image, such as a “you are here” guidance information overlay on the image. As the distance 1304 from the dot 1302 increases, the size of the dots may decrease proportionally. The interval and scale of the dots may be selected to provide adequate connectivity for guidance and may be based on the line-of-sight calculation. FIG. 14 illustrates another embodiment of the guidance information overlay. FIG. 14 is a single-view image 1400 depicting a guidance information overlay that shows alternative routes, according to an exemplary embodiment. As mentioned above, the route calculation function 124 may calculate several route solutions between the origin and destination. These route solutions may comprise some of the same road and/or pedestrian segments while including different segments. The one or more alternative routes may vary in time or distance of travel, but the alternative routes may have different features that may be attractive to a user. For example, alternative routes may be more scenic, have a flatter grade, be well lit at night, handicapped accessible and so on. Referring to FIG. 14, the guidance information overlay includes a route highlight represented by a first series of dots 1402 depicting a first route and a route highlight represented by second series of dots 1404 depicting a second route. The first and second series of dots 1402 and 1404 may be different colors to distinguish the two routes. The first series of dots 1402 highlights a main route, while the second series of dots 1404 highlights an alternative route. The guidance information overlay provides the user an option to follow either route highlight 1402 or 1404 around the fountain. For example, the user may select the second route 1404 because it is tree-lined, which may provide more shade. While, this embodiment is depicted using two routes, the number of routes may be more than two. Further, the route highlights 1402 and 1404 may also overlay road segments 210 in a road network 208. In another embodiment, the guidance information overlays convey additional information about the respective depicted alternative routes. FIG. 15 is a single view image 1500 including guidance information overlays to show alternative routes, according to another exemplary embodiment. In this example, the guidance information overlay includes a route highlight represented by a first series of dots 1502 depicting a first route and a route highlight represented by a second series of dots 1504 depicting a second route. The first series of dots 1502 may highlight a more direct route containing steps, while the second series of dots 1504 may highlight an alternative route that is handicapped accessible. The second series of dots 1504 includes a handicap icon on each of the dots, which describes a feature of the alternative route 1504. The route guidance overlay of the route highlight with handicap icon visually provides useful information to the user of the navigation system 100. For example, the route highlight with the handicap icon may direct the user to a handicapped accessible entrance to a building. Additionally, the user may be pushing a stroller, wearing roller skates, or have a medical condition that makes it difficult to traverse the route highlight 1502 having stairs. While FIG. 15 depicts the use of a handicap icon in the guidance information overlay, a variety of other symbols or icons may be used to highlight the features of a particular route. For example, a tree symbol overlay may be used to identify a tree-lined pathway; a water fountain icon or toilet icon may be used to identify a route that passes by a water fountain or toilets, respectively; and icons or symbols may be used to identify well-lit route, quiet route, scenic route, crowded route, peaceful route, bicycle friendly route, or any other feature. The route guidance function 126 may include the appropriate symbol or icon corresponding to the features of the solution route. Referring again to FIG. 11, after the image with guidance information overlay is created, the user of the navigation system 100 is presented the image with guidance information overlay via the user interface 114. FIG. 16 is a screen shot 1600 of the user interface 114 depicting an image 1602 with guidance information overlays 1604 and 1606, according to an exemplary embodiment. The image 1602 with the guidance information overlays 1604 and 1606 orients the user and provides reassurance that the user is correctly following the solution route to the destination. The user may obtain guidance messages (textual or audio) or a map by touching the message icon or the map icon depicted in the screen shot 1600. FIG. 17 illustrates another embodiment for presenting the image with guidance information overlay to the user. FIG. 17 is a screen shot 1700 of a user interface 114 that provides an image 1702 with guidance information overlay 1704 of a route highlight and a textual guidance message 1706. In the example depicted in FIG. 17, user interface 114 provides the image 1702 of what the pedestrian will see as traveling the solution route, the guidance information overlay 1704 visually directs the user along the route and the textual guidance message 1706 describes the path. In one embodiment, the image 1702 includes labels 1708 identifying features referenced in the textual guidance message, such as “Lake Michigan.” FIGS. 18A and 18B illustrate a further embodiment for presenting the image with guidance information overlay to the user. FIG. 18A is a screen shot 1800 of an image 1802 with a guidance information overlay and a touch-screen icon 1804 for requesting the display of a textual guidance message, while FIG. 18B is a screen shot 1806 of a textual guidance message 1808 and a touch-screen icon 1810 for requesting the display of an image. FIGS. 18A and 18B include the same image 1702 with guidance information overlay and textual guidance message 1706 as depicted in FIG. 17; however, in this example, the image 1802 and the guidance message 1808 are shown on different screens. The user may use the touch-screen icons 1804, 1810 to toggle between the photograph 1802 and the pedestrian guidance message 1808. While this example uses a touch-screen input mechanism to the user interface 114, any other input mechanism to the user device may be used. The screen shots 1600, 1700, 1800 and 1806 have been depicted on a personal digital assistant; however, other user devices, such as a cellular telephone, a vehicle navigation system, and a computer may also be used to display the images and associated guidance information overlays. Further, a user may obtain the images and associated guidance information overlays prior to traveling the solution route. As another example, a person may obtain the images from a stationary computer, which may be printed and taken with the user. As yet another example, the user may obtain the images with the guidance information overlays from a public-access device, such as an Internet web site, a computer terminal, or a kiosk. Additionally, the user may take a virtual tour of the solution route using the images obtained prior to traveling. VI. Alternative Implementation with Information Overlays on Images The above description presented images with guidance information overlays for guiding a user of a navigation system 100 along a solution route to a desired destination. FIG. 19 illustrates another implementation of the images with information overlays. FIG. 19 is a scenic image 1900 including label overlays 1902, according to an exemplary embodiment. The label overlays identify popular locations in the cityscape image 1900. As illustrated in FIG. 19, the information overlays include text labels identifying the names of a variety of buildings in the image 1900. In addition to labels for buildings, the image may include labels for any point of interest or geographic feature in the image. In another embodiment, the information overlays may comprise addresses corresponding to the buildings. In yet another embodiment, the information overlays may comprise historical, tourist type or advertisement labels. A user may use the information overlays of the image for entertainment purposes. The information overlays may allow the user to identify important building and structures, which may be of interest to tourists, architects, and the like. In one embodiment, the navigation system 100 presents the image 1900 with label overlays 1902 on the user interface 114 for the user to enter a location. The user may select a label or building on the image 1900 to enter as his or her desired location. For example, if the user device is a PDA, the pedestrian may select a label by touching a touch-screen display using a stylus. In another embodiment, the user may enter the label name via the user interface as the desired location. In one embodiment, the user may use the image 1900 to enter a desired destination. As discussed above in conjunction with FIG. 1, the navigation system 100 includes the route calculation function 124. The route calculation function 124 receives a request to calculate a route to a desired destination. The request may be in the form of a request to enter a destination using an image with information overlays. The user is then presented with the image with information overlays. For example, a tourist in Chicago may request to enter a destination using the scenic image 1900 and the navigation system provides the user with the image 1900. The user selects a destination using the image 1900, and the route calculation function 124 uses the entered destination to calculate a solution route from the current location of the user to the entered destination. In another embodiment, the user enters the starting location for the route using the image 1900. For example, a tourist kiosk provides the image 1900 and enables users to determine routes from and to various destinations. After the starting location and destination location have been entered, the route calculation function 124 attempts to determine one or more solution routes between the starting location and the destination location as described above. Additionally, the navigation system 100 provides route guidance functions and features for the solution route to guide the user along the solution route to the entered desired destination. The route guidance may comprise images with guidance information overlays, textual messages or any other guidance information. Additionally, the navigation system 100 may provide a map display to the user. Additionally, the image 1900 may be used to enter a location for any navigation feature and function. In another embodiment, the user may use the image 1900 to enter a desired point of interest to request information about the point of interest. For example, the user may request information about businesses, times of operation, telephone numbers and any other information. Furthermore, the label overlays 1902 of the image may contain advertisements. It is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is understood that the following claims including all equivalents are intended to define the scope of the invention
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to a method and system for providing navigation features and functions, and more particularly to a method and system for collecting images and providing navigation features using the images. Vehicle navigation systems are available that provide end users with various navigation-related functions and features. For example, some navigation systems are able to determine an optimum route to travel along a road network from an origin location to a destination location in a geographic region. Using input from the end user, and optionally from equipment that can determine the end user's location (such as a GPS system), the navigation system can examine various potential routes between the origin and destination locations to determine the optimum route. The navigation system may then provide the end user with information about the optimum route in the form of guidance that identifies the driving maneuvers for the end user to travel from the origin to the destination location. The guidance may take the form of visual and/or audio instructions that are provided along the way as the end user is traveling the route. Some navigation systems are able to show detailed maps on displays outlining the route, the types of maneuvers to be taken at various locations along the route, locations of certain types of features, and so on. In order to provide these and other navigation-related functions and features, navigation systems use geographic data. The geographic data may be in the form of one or more geographic databases that include data representing physical features in the geographic region. The geographic database includes information about the represented geographic features, such as the positions of the roads, speed limits along portions of roads, address ranges along the road portions, turn restrictions at intersections of roads, direction restrictions, such as one-way streets, and so on. Additionally, the geographic data may include points of interest, such as restaurants, hotels, airports, gas stations, stadiums, police stations, and so on. Although navigation systems provide many important features, there continues to be room for new features and improvements. One area in which there is room for improvement relates to providing improved guidance for following the route. In some situations, additional guidance and orientation information would be helpful when following the route. For example, some areas may be difficult for a user of a navigation system 100 to traverse because of the many road segments intersecting in the area and the many different turn options available to travel. Additionally, pedestrians may find additional guidance and orientation information helpful when traversing a route because pedestrians have a greater degree of freedom of motion and may become more frequently confused as to their orientation to destination. Accordingly, it would be beneficial to have a way to collect and provide images that may be used to provide improved navigation-related functions and features.
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<SOH> SUMMARY OF THE INVENTION <EOH>A method and system of operating a navigation system is described in the embodiments disclosed herein. The method provides an image of a geographic area through which a portion of a route between an origin and destination passes. The image may be an approximate 360-degree image. The image may include a guidance information overlay on the image, such as a route highlight, a maneuver arrow, an indication of a path that has been traveled, a main route and alternative route, and a label. The images with the guidance information overlays may orient and provide guidance to the user of the navigation system. In another embodiment, the method of operating a navigation system provides an image of a geographic region and overlays the image with labels identifying locations in the image. The method enables a user of the navigation system to enter one of the locations and provides a navigation feature for the entered location. The image may be a single-view photograph or a panoramic photograph. The locations identified with labels may be points of interests.
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20040630
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20081202
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20060105
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62904.0
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G01C2130
| 2
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ZANELLI, MICHAEL J
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METHOD OF OPERATING A NAVIGATION SYSTEM USING IMAGES
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UNDISCOUNTED
| 0
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ACCEPTED
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G01C
| 2,004
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10,880,851
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ACCEPTED
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Salts of fenofibric acid and pharmaceutical formulations thereof
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In one aspect, the present invention relates to a formulation in the form of molecular dispersion comprising i) fenofibric acid, a physiologically acceptable salt or derivative thereof and optionally other active substances, ii) a binder component comprising at least one enteric binder, and optionally iii) other physiologically acceptable excipients. In a second aspect, the present invention relates to novel salts of fenofibric acid that are photostable when compared to other salts of fenofibric acid.
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1. A salt of fenofibric acid selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine. 2. The salt of claim 1 wherein said salt is choline. 3. The salt of claim 1 wherein said salt is ethanolamine. 4. The salt of claim 1 wherein said salt is diethanolamine. 5. The salt of claim 1 wherein said salt is piperazine. 6. The salt of claim 1 wherein said salt is calcium. 7. The salt of claim 1 wherein said salt is tromethamine. 8. A pharmaceutical formulation in a form of a molecular dispersion comprising: i. a salt of fenofibric acid selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine; and ii. a binder component comprising at least one enteric binder. 9. The formulation of claim 8 further comprising a physiologically acceptable excipient. 10. The formulation as claimed in claim 8, wherein the enteric binder is an enteric polymer. 11. The formulation as claimed in claim 10, wherein the enteric polymer is selected from hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate succinate, carboxymethylethylcellulose, cellulose acetate phthalate, cellulose acetate trimellitate and carboxymethylcellulose sodium. 12. The formulation as claimed in claim 10, wherein the enteric polymer is a copolymer of (meth)acrylic acid and at least one alkyl (meth)acrylic acid ester. 13. The formulation as claimed in claim 12, wherein the alkyl (meth)acrylic acid ester is methyl methacrylate. 14. The formulation as claimed in claim 8, wherein the formulation comprises about 5 to about 60% by weight of said salt and about 20 to about 95% by weight of a binder component. 15. The formulation of claim 9, wherein the formulation comprises about 1 to about 60% of a physiologically acceptable excipient.
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RELATED APPLICATION INFORMATION This application is a continuation-in-part application of PCT/EP03/14331 filed on Dec. 16, 2003 which claims priority to U.S. Ser. No. 60/453,694, filed on Dec. 17, 2002, each of which are incorporated by reference. This application also claims priority to U.S. Ser. No. 60/499,284 filed on Aug. 29, 2003 and U.S. Ser. No. 60/499,285 filed on Aug. 29, 2003, each of which are incorporated by reference. FIELD OF THE INVENTION In one aspect, the present invention relates to pharmaceutical formulations comprising fenofibric acid, a physiologically acceptable salt or derivative thereof, processes of making said formulations, such as by melt extrusion, and the use of these formulations for the oral administration of fenofibric acid, a physiologically acceptable salt or derivative thereof. In a second aspect, the present invention relates to novel salts of fenofibric acid that exhibit photostability when compared to other salts of fenofibric acid. These photostable salts are useful for pharmaceutical formulations in a form of molecular dispersions that contain at least one of these novel salts. These novel salts can be used to treat hyperlipidemia or coronary heart diseases. BACKGROUND OF THE INVENTION Fenofibrate is a well-known lipid regulating agent which has been commercially available for a long time. Fenofibrate is usually orally administered. After its absorption, which is known to take place in the duodenum and other parts of the gastrointestinal tract, fenofibrate is metabolized in the body to fenofibric acid. In fact, fenofibric acid represents the active ingredient of fenofibrate. In other words, fenofibrate is a so-called prodrug which is converted in vivo to the active molecule. After oral administration of fenofibrate, fenofibric acid is found in plasma. U.S. Pat. Nos. 4,179,515 and 4,235,896 disclose the preparation of fenofibric acid and also describe acid addition salts of amine containing analogs. U.S. Pat. No.4,372,954 discloses the moroxydine salt of fenofibric acid as useful for the inhibition of platelet aggregation and for lowering fibrinogen. Spanish patent ES 474039 discloses the use of the cinnarizine-salt of fenofibric acid for the reduction of triglyceride levels and the sodium salt of fenofibric acid (in solution) has also been disclosed (Bosca et al., Photochemistry and Photobiology, 1999, 70(6), 853-857). Fenofibrate is known to be nearly insoluble in water and requires special pharmaceutical formulations in order to ensure good bioavailability, especially after oral administration. Accordingly, fenofibrate has been prepared in several different formulations, (see WO 00/72825 and the citations provided therein, such as U.S. Pat. Nos. 4,800,079, 4,895,726, 4,961,890, EP-A 0 793 958 and WO 82/01649). Additional formulations of fenofibrate are described in WO 02/067901 and citations provided therein, such as U.S. Pat. Nos. 6,074,670 and 6,042,847. The fenofibrate products currently on the market involve a formulation comprising a micronized drug substance in capsules and/or tablets. However, the insolubility of fenofibrate in water may still negatively impact the in vivo performance of the product. One approach to mitigate the bioavailability issue is to render the crystalline drug amorphous, leading to accelerated drug release. However, recrystallization of amorphous materials could occur, especially for insoluble molecules such as fenofibrate. Thereupon, one object of the present invention is to provide pharmaceutical formulations that make fenofibric acid sufficiently bioavailable and prevent recrystallization of the active substance. This object is achieved by formulations that comprise fenofibric acid, a physiologically acceptable salt or a physiologically acceptable derivative thereof that is embedded in an enteric binder. It is another object of the present invention to provide novel salts of fenofibric acid that result in a product having improved photostability when compared to fenofibric acid and other salts of fenofibric acid. SUMMARY OF THE INVENTION In one aspect, the present invention relates to a pharmaceutical formulation comprising: i) fenofibric acid, or a physiologically acceptable salt or derivative thereof and optionally, other active ingredients (which is collectively referred to as the “active substance component); ii) a binder component comprising at least one enteric binder; and optionally, iii) other physiologically acceptable excipients. The physiologically acceptable derivative of fenofibric acid can be fenofibrate. Additionally, the fenofibric acid, physiologically acceptable salt or derivative thereof can be present in the formulation as a molecular dispersion. The binder employed in the above-described formulation can be an enteric polymer, such as those selected from the group consisting of: hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate succinate, carboxymethylethylcellulose, cellulose acetate phthalate, cellulose acetate trimellitate and carboxymethylcellulose sodium. Additionally, the enteric polymer can be a copolymer, such as a copolymer of (meth)acrylic acid and at least one alkyl (meth)acrylic acid ester. The alkyl (meth)acrylic acid ester can be methyl methacrylate. The copolymer can have a ratio of free carboxyl groups to esterified carboxyl groups of about 2:1 to 1:3, preferably, about 1:1. The other physiologically acceptable excipients can be a flow regulator, such as a highly dispersed silica gel. Preferably, the above-described formulation comprises i) about 5 to about 60% by weight, preferably about 7 to about 40% by weight and most preferably, about 10 to about 30% by weight of active substance component; ii) about 20 to about 95% by weight, preferably about 30 to about 90% by weight and most preferably, about 40 to about 80% by weight, of a binder component; iii) 0 to about 75% by weight, preferably about 1 to about 60% by weight and most preferably, about 5 to about 40% by weight, of other physiologically acceptable excipients. It is preferred that the enteric binder employed in the above-described formulation comprise about 5 to about 95% by weight, more preferably from about 10 to about 70% by weight and most preferably, about 30 to about 60% by weight of the binder component (ii). Moreover, the content of the active substance component (i) relative to the binder component (ii) is from about 1 to about 50% by weight, preferably about 10 to about 40% by weight and most preferably about 20 to about 30% by weight. The above-described formulation can be obtained by melt extrusion of a mixture comprising fenofibric acid, a physiologically acceptable salt or derivative thereof, binder and optionally, other active substances and/or physiologically acceptable excipients. The above-described formulation can be used in a method of oral administration of fenofibric acid, a physiologically acceptable salt or derivative thereof. This method involves the step of administering the above-described formulation and optionally, other excipients, as a dosage form to a mammal, preferably a human. In another aspect, the present invention relates to a salt of fenofibric acid selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine. In yet another embodiment, the present invention relates to a pharmaceutical formulation in the form of a molecular dispersion comprising a salt of fenofibric acid that is selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine and a binder component comprising at least one enteric binder. Preferably, said formulation comprises about 5 to about 60% by weight of one of said novel salts and about 20 to about 95% by weight of a binder component. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in two different aspects. Each of these two aspects of the present invention are treated separately under different headings for the convenience of the reader and should not be construed as limiting the present invention in any way. These headings are “Pharmaceutical Formulations of Fenofibric Acid, Physiologically Acceptable Salts or Derivatives Thereof” and “Novel Salts of Fenofibric Acid”. 1. Pharmaceutical Formulations of Fenofibric Acid, Physiologically Acceptable Salts or Derivatives Thereof In one aspect, the present invention relates to pharmaceutical formulations, preferably solid formulations, comprising a mixture of: i) fenofibric acid, or a physiologically acceptable salt or derivative thereof and optionally other active substances; ii) a binder component comprising at least one enteric binder; and optionally iii) other physiologically acceptable excipients. As used herein, the term “fenofibric acid” refers to 2-[4-(4-chlorobenzoyl)phenoxy]-2-methyl-propanoic-acid, having the following formula I The physiologically acceptable salts of the present invention are preferably base addition salts. The base addition salts include salts with inorganic bases, including, but not limited to, metal hydroxides or carbonates of alkali metals, alkaline earth metals or transition metals, or with organic bases, including, but not limited to, ammonia, basic amino acids such as arginine and lysine, amines, e.g. methylamine, dimethylamine, trimethylamine, triethylamine, ethylamine, diethylamine, ethylenediamine, ethanolamine, diethanolamine, 1-amino-2-propanol, 3-amino-1-propanol or hexamethylenetetraamine, saturated cyclic amines having 4 to 6 ring carbon atoms, including, but not limited to, piperidine, piperazine, pyrrolidine and morpholine, and other organic bases, for example N-methylglucamine, creatine and tromethamine, and quaternary ammonium compounds, including, but not limited to, tetramethylammonium and the like. Salts with organic bases are preferably formed with amino acids, amines or saturated cyclic amines. Preferred salts with inorganic bases are preferable formed with Na, K, Mg and Ca cations. The physiologically acceptable derivatives of the present invention are preferably carboxylic acid derivatives that are reconvertable in vivo to the free carboxylic acid. Thus, the preferred physiologically acceptable derivatives of fenofibric acid are prodrugs of fenofibric acid. The conversion of said prodrugs in vivo may occur under the physiological conditions that the prodrug experiences during its passage or may involve cleavage by enzymes, especially esterases, accepting the prodrug as substrate. The physiologically acceptable derivatives of the present invention are fenofibric acid derivatives having the following formula II wherein R is OR1, —NR1R2, —NH-alkylene-NR1R2 or —O-alkylene-NR1R2, with R1 and R2 being identical or different from each other and representing a hydrogen atom, alkyl, alkoxyalkyl, alkoyloxyalkyl, alkoxycarbonyl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, trialkylammoniumalkyl, cycloalkyl, aryl or arylalkyl substituted on the aromatic residue by one or more halogen, methyl or CF3 groups, or R1 and R2 forming together with the nitrogen atom to which they are connected, a 5- to 7-membered aliphatic heterocyclic group which may enclose a second heteroatom selected from the group consisting of N, O, and S, and which may be substituted by one or more halogen, methyl or CF3 groups. Particularly preferred physiologically acceptable derivatives are fenofibric acid esters, i.e., derivatives of formula II wherein R is OR1 and R1 is other than hydrogen. These esters include derivatives of formula II wherein R1 in —OR1 represents an alkyl group having from 1 to 6 carbon atoms, an alkoxymethyl group having from 2 to 7 carbon atoms, a phenylalkyl group composed of an alkylene group having from 1 to 6 carbon atoms and a phenyl group, a phenyl group, an acetoxymethyl group, a pivaloyloxymethyl group, an ethoxycarbonyl group and a dimethylaminoethyl group. Especially preferred according to the present invention are alkyl esters of fenofibric acid. In one embodiment, the present invention relates to formulations comprising i) the 1-methylethyl ester (isopropyl ester) of fenofibric acid, i.e. fenofibrate (INN). The active substance (also known as the active pharmaceutical ingredient or “API”) component i) of the formulations of the present invention comprise fenofibric acid, a physiologically acceptable salt or derivative thereof. Mixtures of one or more of these forms are possible. For reasons of simplicity, this part of the active substance component is hereinafter referred to as the “fenofibric acid content”. Besides the fenofibric acid content, component i) of the formulations may comprise other active substances, particularly those having an action like that of fenofibric acid, e.g. other lipid regulating agents, such as, but not limited to, further fibrates, e.g. bezafibrate, ciprofibrate and gemfibrocil, or statins, e.g. lovastatin, mevinolin, pravastatin, fluvastatin, atorvastatin, itavastatin, mevastatin, rosuvastatin, velostatin, synvinolin, simvastatin, cerivastatin and numerous others mentioned in, for instance, in WO 02/67901 and the corresponding citations therein as well as expedient active substances of other types. In one embodiment, the present invention comprises single-drug products that comprise an active substance component i) that essentially consists of fenofibric acid or a physiologically acceptable salt of fenofibric acid or a physiologically acceptable derivative of fenofibric acid or of a mixture thereof. As used with respect to the active substance, the term “essentially” refers to a percentage ratio of at least 90%, preferably of at least 95% and most preferably of at least 98%. The active substance component ordinarily constitutes about 5 to about 60% by weight, preferably about 7 to about 40% by weight and, in particular, about 10 to about 30% by weight of the formulation. Data in % by weight are based, unless indicated otherwise, on the total weight of the formulation. The formulation base of the formulations of the present invention comprises physiologically acceptable excipients, namely, at least one binder and optionally other physiologically acceptable excipients. Physiologically acceptable excipients are those known to be usable in the pharmaceutical technology sectors and adjacent areas, particularly, those listed in relevant pharmacopeias (e.g. DAB, Ph. Eur., BP, NF, USP), as well as other excipients whose properties do not impair a physiological use. The binder component of the formulations of the present invention may also be understood to include a binder which at least in part forms a binder matrix, particularly, a polymer matrix, in which the active substance is embedded. Binders suitable for use in the present invention include, solid meltable solvents. The binder matrix serves to take up and, especially, to dissolve at least part of the active substance component, especially the fenofibric acid content. To this extent, the binder is also a solvent. In relation to the active substance which is in the form of a molecular dispersion and dissolved, it is possible to speak of a solid solution of the active substance in the binder, the binder being either in crystalline form or in amorphous form. Preferably, the binder component is at least partly soluble or swellable in an aqueous media, expediently under the conditions of use, that is to say, in particular physiological conditions. An enteric binder may be defined as a binder, the solubility or swellability of which increases with increasing pH and vice versa. Particularly preferred are binders that are at least partly soluble or swellable in aqueous media having a pH of from about 5 to about 9, more preferably from about 6 to about 8 and most preferably from about 6.5 to about 7.5. Within the framework of this present description, aqueous media include water and mixtures of water and other components that comprise at least 50% by weight, preferably at least 70% by weight and most preferably at least 90% by weight of water. Aqueous media include, but are not limited to, body fluids such as fluids of the digestive tract, e.g. gastric juices, intestinal juices and saliva, blood; aqueous vehicles for use in pharmaceutical formulations in the drugs and food supplement sectors, e.g. vehicles which can be administered orally or parenterally, such as drinking water or water for injections. As used herein, “swelling” refers to a process in which the volume and/or shape of a solid body, such as, for example, a solid formulation of the present invention, changes on exposure to liquids, vapors and gases. Swellable or soluble polymers are preferably hydrophilic polymers that are able to accumulate water at least on the surface and/or take up water between the polymer chains, mainly by adsorption. Limited swelling usually results in gel formation, which is why polymers capable of limited swelling and usable according to the present invention can be selected from the polymers commonly known as gel formers. Unlimited swelling usually leads to the formation of solutions or colloidal solutions, which is why polymers capable of unlimited swelling and usable according to the present invention can be selected from the polymers which form at least colloidal solutions in a particular aqueous medium. It is expedient to take into account, especially in relation to body fluids, particularly those of the gastrointestinal tract, that there may be local variations in the physiological conditions, especially the pH. Since it is preferred, according to the present invention, that the active substance be taken up mainly in the duodenum, jejunum and/or ileum, it is preferable for the binder to be swellable or soluble under the conditions prevailing in the duodenum, jejunum and/or ilium. In particular, it is preferred that only slight or, preferably, essentially no swelling or dissolution of the polymer to take place in the preceding sections of the gastrointestinal tract, especially in the stomach. It is preferred that at least one binder of the binder component be a polymeric material, particularly an enteric polymer. As used herein, the term “enteric polymer”, which is a term of the art, refers to a polymer which is preferentially soluble in the less acid environment of the intestine relative to the more acid environment of the stomach. Enteric polymers are pH sensitive. Typically, the polymers are carboxylated and interact (swell) very little with water at low pH, while at high pH the polymers ionize, causing swelling, or dissolving of the polymer. Therefore, the binder component can be designed to remain intact in the acidic environment of the stomach (preventing recrystallization of the active substance in the stomach), but dissolve in the more alkaline environment of the intestine. The enteric polymer may be made from a conventional material. It is preferred that at least one binder of the binder component be selected from enteric polymers such as, but not limited to, suitable cellulose derivatives, e.g. cellulose acetate phthalates, cellulose acetate succinates, cellulose acetate trimellitates, carboxyalkyl(alkyl)celluloses and hydroxyalkyl(alkyl) cellulose phthalates; suitable polyvinyl-based polymers and copolymers, e.g. polyvinylacetatephthalate, polyvinylbutyrate acetate, vinyl acetate-maleic anhydride copolymer, styrene-maleic mono-ester copolymer; and suitable acrylic/methacrylic polymers and copolymers, e.g. methyl acrylate-methacrylic acid copolymer, and methacrylate- methacrylic acid-octyl acrylate copolymer. Preferred enteric binders are pharmaceutically acceptable acrylic and methacrylic acid polymers and copolymers. These include copolymers with anionic characteristics based on (meth)acrylic acid and alkyl (meth)acrylic acid esters such as, but not limited to, methyl (meth)acrylate. Preferably, these copolymers have weight average molecular weights of around 50,000 to 300,000, most preferably around 100,000 to 150,000, e.g. around 135,000. The ratio of free carboxyl groups to esterified carboxyl groups of said copolymers is preferably in the range of around 2:1 to 1:3, most preferably, 1:1 to 1:2. Specific examples of copolymers that can be used include the acrylic resins having the proprietary names Eudragit® L and S that are based on methacrylic acid and methyl methacrylate that have a ratio of free carboxyl groups to esterified carboxy groups of around 1:1 and 1:2, respectively. Among these, copolymers of the Eudragit® L type are preferred, most preferred is Eudragit® L 100, a pH dependent anionic polymer solubilizing above pH 6.0 for targeted drug delivery in the jejunum and Eudragit® S 100, a pH dependent anionic polymer solubilizing above pH 7.0 for targeted drug delivery in the ileum. Other preferred enteric binders that can be used herein are pharmaceutically acceptable cellulose derivatives. These include, but are not limited to, carboxymethylethylcellulose (CMEC) and carboxymethylcellulose sodium (sodium cellulose glycolate), and particularly hydroxypropylmethylcellulose phthalate, especially hypromellose phthalates such as 220824 and 220731, hydroxypropylmethylcellulose acetate succinate (AQOAT), cellulose acetate phthalate (CAP), and cellulose acetate trimellitate (CAT). Such polymers are sold under the tradename Cellacefate® (cellulose acetate phthalate) from Eastman Chemical Co., Aquateric® (cellulose acetate phthalate aqueous dispersion) from FMC Corp., Aqoat® (hydroxypropylmethylcellulose acetate succinate aqueous dispersion), and HP50 and HP55 (hydroxypropylmethylcellolose phthalates) from ShinEtsu K. K. Additionally, enteric binders include casein. These enteric binders may be used either alone or in combination, and optionally together with binders other than those mentioned above. Thereupon, the binder component of the formulations of the present invention comprises at least one of the enteric binders described above and particularly, at least one enteric polymer. The binder component may comprise other binders of these types and/or of other types. The properties of the formulations of the present invention can be altered by the nature of the chosen binder(s) or the admixture of different binders. In particular, it is possible in this manner to control the release of active substance. In another embodiment of the present invention, the binder component comprises of one of the enteric binders described above. In another embodiment of the present invention, the enteric binder component comprises a mixture of at least two of the enteric binders described above. In this case, the enteric binder(s) constitute(s) 100% by weight of the binder component (ii). In yet a further embodiment of the present invention, the binder component comprises, in addition to one or more than one enteric binder, at least one other (non-enteric) binder. In this embodiment, the enteric binder preferably constitutes about 5 to about 95% by weight, more preferably about 10 to about 70% by weight and, most preferably, about 30 to about 60% by weight of the binder component (ii). If at least one other (non-enteric) binder is present, it is preferred that said other (non-enteric) binder that is to be used in combination with the enteric binder be selected from the group consisting of: synthetic polymers such as, but not limited to, polyvinyllactams, in particular polyvinylpyrrolidone (PVP); copolymers of vinyllactams such as, but not limited to, N-vinylpyrrolidone, N-vinylpiperidone and N vinyl-ε-caprolactam, but especially N-vinylpyrrolidone, with (meth)acrylic acid and/or (meth)acrylic esters, such as, but not limited to, long-chain (meth)acrylates, e.g. stearyl (meth)acrylate, dialkylaminoalkyl (meth)acrylates, which may be quaternized, and maleic anhydride, vinyl esters, especially vinyl acetate, vinylformamide, vinylsulfonic acid or quaternized vinylimidazole; copolymers of vinyl acetate and crotonic acid; partially hydrolyzed polyvinyl acetate; polyvinyl alcohol; (meth)acrylic resins such as, but not limited to, poly(hydroxyalkyl (meth)acrylates), poly(meth)acrylates, acrylate copolymers; polyalkylene glycols such as, but not limited to, polypropylene glycols and polyethylene glycols, preferably with molecular weights above 1,000, more preferably above 2,000 and most preferably above 4,000 (e.g. polyethylene glycol 6,000); polyalkylene oxides such as, but not limited to, polypropylene oxides and, in particular polyethylene oxides, preferably of low molecular weight, especially with weight average molecular weights of less than 100,000; polyacrylamides; polyvinylformamide (where appropriate partially or completely hydrolyzed); modified natural polymers, e.g. modified starches and modified celluloses, such as, but not limited to, cellulose esters and, particularly, cellulose ethers, e.g. methylcellulose and ethylcellulose, hydroxyalkylcelluloses, in particular hydroxypropylcellulose, hydroxyalkylalkylcelluloses, particularly hydroxypropylmethylcellulose or hydroxypropylethylcellulose; starch degradation products, particularly, starch saccharification products, such as maltodextrin; natural or predominantly natural polymers such as, but not limited to, gelatin, polyhydroxyalkanoates, e.g. polyhydroxybutyric acid and polylactic acid, polyamino acids, e.g. polylysine, polyasparagine, polydioxanes and polypeptides, and mannans, especially galactomannans; and nonpolymeric binders such as, but not limited to, polyols, for example those described in WO 98/22094 and EP 0 435 450, in particular sugar alcohols such as, but not limited to, maltitol, mannitol, sorbitol, cellobiitol, lactitol, xylitol and erythritol, and isomalt (Palatinit). Of the aforementioned binders, the polymeric binders, particularly, the modified natural polymers, especially modified starches and cellulose ethers, and particularly, the synthetic polymers, especially polyvinylpyrrolidone and copolymers of vinyllactams, are preferred. It is particularly preferred that at least one other binder of the binder component be selected from polyvinylpyrrolidones, e.g. Kollidong® K25, N-vinylpyrrolidone/vinyl acetate copolymers, especially copovidone, e.g. Kollidon® VA 64, and low molecular weight cellulose derivatives such as low molecular weight hydroxypropylcellulose, e.g. Klucel®EF with weight average molecular weights of about 45,000 to about 70,000 or about 80,000, and low molecular weight hydroxypropylmethylcellulose, e.g. Methocel® E3, E5 and E7. Binder components that are preferred for the process are those which are melt-processable. Polymers that can be used as polymeric binders are those which have a K value (according to H. Fikentscher, Cellulose-Chemie 13 (1932), pp. 58-64 and 71-74) in the range between 10 and 100, preferably, between 15 and 80. In a preferred embodiment, the binder component has a glass transition temperature of more than about 80° C., preferably more than about 90° C. and most preferably of more than about 100° C. In addition, the suitability of glass transition temperatures in this range is governed by the necessary melt-processability of the binder or binder-containing mixtures. The content of the binder component (ii) in the formulation of the present invention is ordinarily from about 20 to about 95% by weight, preferably about 30 to about 90% by weight and most preferably about 40 to about 80% by weight. In a particular embodiment, the present invention relates to formulations wherein the fenofibric acid, a physiologically acceptable salt or derivative thereof is in the form of a molecular dispersion. The term “molecular dispersion” as used herein and as known to one skilled in the art, describes systems in which a substance, in the present case at least part and particularly the predominant part of the fenofibric acid content, is homogeneously dispersed in the binder component. In a molecular dispersion, the dispersed substance is free of interfaces. In this case, the binder usually forms a matrix which, according to the present invention, is formed by the binder component or at least by a predominant part of the binder component, advantageously, the enteric binder. According to this embodiment, the content of active substance crystals in a formulation of the present invention is preferably below about 15% and most preferably, below about 10%. Statements about crystal contents relate to the total amount of the active substance(s), particularly, the fenofibric acid content. A formulation of the present invention that is essentially free of active substance crystals represents a particular embodiment of the present invention. The reduction in the crystal content is associated with an increase in the homogenization of the active substance in the matrix. Molecular dispersion systems are, according to a particular embodiment, solid at room temperature (about 25° C.), but melt-processable at higher temperatures. Formulations of the present invention in which there is no crystalline contents for essentially any constituent (essentially amorphous or crystal-free formulations) represent an additional embodiment of the present invention. The state of such molecular dispersions can be investigated using known analytical methods, e.g. by differential scanning calorimetry (DSC) or wide-angle X-ray scattering measurements (WAXS measurements). Measurement of a molecular dispersion in DSC analysis lacks the usually endothermic, peak due to melting that occurs with the crystalline pure substance. Another possibility for identifying a molecular dispersion is the reduction in intensity and/or absence of typical X-ray diffraction signals in WAXS analysis. For the purpose of forming molecular dispersions and, in particular, solid solutions by at least part of the active substance component in the binder component, the content of active substance component based on the binder component is present from about 1 to about 50% by weight, preferably about 10 to about 40% by weight and more preferably about 20 to about 30% by weight. Formulations of the present invention may contain, in addition to a binder component, further physiologically acceptable excipients (excipient component iii). Such excipients may facilitate the production of the formulation and/or modulate its properties. The nature and amount are chosen so that they do not impair development of the special properties of the formulations of the present invention or contribute to destabilizing this system. Excipients are usually conventional pharmaceutical excipients, for example, fillers such as, but not limited to, sugar alcohols, e.g. lactose, microcrystalline cellulose, mannitol, sorbitol and xylitol, isomalt (cf. DE 195 36 394), starch saccharification products, talc, sucrose, cereal corn or potato starch, where present in a concentration of about 0.02 to about 50, preferably about 0.20 to about 20% by weight based on the total weight of the mixture; lubricants, glidants and mold release agents such as, but not limited to, magnesium, aluminum and calcium stearates, talc and silicones, and animal or vegetable fats, especially in hydrogenated form and those which are solid at room temperature. These fats preferably have a melting point of 30° C. or above. Technically preferred in relation to the melt extrusion process are, as described in DE 197 31 277, triglycerides of C12, C14, C16 and C18 fatty acids or, to improve the processing properties, sodium stearylfumarate, lecithin, as described in connection with the extrusion of an isomalt-containing polymer/active substance melt in DE 195 36 394. It is also possible to use waxes such as, but not limited to, carnauba wax. These fats and waxes may be admixed alone or together with mono- and/or diglycerides or phosphatides, particularly, lecithin. The mono- and diglycerides are preferably derived from the abovementioned fatty acid types. Where present, the total amount of excipients in the form of lubricants and mold release agents is preferably about 0.1 to about 10% by weight and, more preferably, about 0.1 to about 2% by weight, based on the total weight of the mixture; flow regulators, e.g. colloidal silica (highly dispersed silicon dioxide), especially the high-purity silicon dioxides having the proprietary name Aerosil®, where present, in an amount of about 0.1 to about 5% by weight based on the total weight of the mixture; dyes such as, but not limited to, azo dyes, organic or inorganic pigments or dyes of natural origin, with preference being given to inorganic pigments e.g. iron oxides, where present, in a concentration of about 0.001 to about 10, preferably about 0.1 to about 3% by weight, based on the total weight of the mixture; stabilizers such as, but not limited to, antioxidants, light stabilizers, hydroperoxide destroyers, radical scavengers, stabilizers against microbial attack; plasticizers, especially those described below. It is also possible to add wetting agents, preservatives, disintegrants, adsorbents and mold release agents, and surfactants, especially anionic and nonionic, such as, for example, soaps and soap-like surfactants, alkyl sulfates and alkylsulfonates, salts of bile acids, alkoxylated fatty alcohols, alkoxylated alkylphenols, alkoxylated fatty acids and fatty acid glycerol esters, which may be alkoxylated, and solubilizers such as Cremophor® (polyethoxylated castor oil), Gelucire® and Labrafil® vitamin E TPGS and Tween® (ethoxylated sorbitan fatty acid esters) (cf., for example, H. Sucker et al. Pharmazeutische Technologie, Thieme-Verlag, Stuttgart 1978). Excipients, for the purpose of the present invention, also refers to substances for producing a solid solution with the active substance. Examples of these excipients are pentaerythritol and pentaerythritol tetraacetate, urea, phosphatides such as lecithin, polymers such as, for example, polyethylene oxides and polypropylene oxides and their block copolymers (poloxamers) and citric and succinic acids, bile acids, stearins and others as indicated, for example, by J. L. Ford, Pharm. Acta Hely. 61, (1986), pp. 69-88. Also regarded as pharmaceutical excipients are additions of acids and bases to control the solubility of an active substance (see, for example, K. Thoma et al., Pharm. Ind., 51, (1989), pp. 98-101). Excipients as used in the present invention also include vehicles specific for the dosage form, i.e. appropriate for a particular dosage form, in particular peroral and, especially, tablets and capsules, also low-melting or liquid excipients such as polyalkylene glycols of low molecular weight, such as polyethylene glycol and/or polypropylene glycol with weight average molecular weights of less than about 1,000, water or suitable aqueous systems. It is also possible to add excipients such as, but not limited to, masking flavors and odor-masking agents, particularly, sweeteners and odorants. Further particular embodiments involving excipients are known to those skilled in the art as described, for example, in Fiedler, H. B., Lexikon der Eilfsstoffe fir Fharmazie, Kosmetik, and angrenzende Gebiete, 4th edition, Aulendorf: ECV-Editio-Cantor-Verlag (1996). The only requirement for the suitability of the excipients is usually the compatibility with the active substances and excipients used. The excipients ought not to impair the formation of molecular dispersions. The excipient component in solid formulations of the present invention preferably comprises at least one of the excipients described above. It may comprise other excipients of these types and/or other types. One embodiment of the present invention comprises formulations with excipient component iii). In this embodiment, the content of the other physiologically acceptable excipients in the formulations of the present invention can be up to about 75% by weight, preferably up to about 60% by weight and, more preferably, up to about 40% by weight. A particular embodiment of the present invention comprises formulations which comprise: i) fenofibric acid or fenofibrate; ii) at least one binder selected from enteric polymers; and iii) optionally, other physiologically acceptable excipients, in particular a flow regulator, e.g. highly disperse silica gel. The formulations of the present invention preferably contain less than about 7% by weight and, more preferably, less than about 4% by weight of water. A preferred embodiment is represented by less than about 2% by weight of water. From the viewpoint of a formulation that can be administered orally, it is particularly preferred for at least part of the binder component to be designed such that the release of active substance at acidic pH is delayed and recrystallization of the active in the stomach prevented. The formulations of the present invention have a solid consistency. As used herein, the term “solid” has in this connection the meaning assigned to it in the relevant pharmacopeias in connection with pharmaceutical preparations. In the wider sense, solid formulations of the present invention also include those with a semisolid consistency, which may result in formulations having a high fenofibrate content. These formulations are viscous or highly viscous formulations that can be molded at room temperature. The suitability of semisolid formulations for being expediently processed, according to the present invention by means of extrusion, is important. The present invention also relates to the use of formulations of the present invention as dosage forms, particularly for oral administration of fenofibric acid or a physiologically acceptable salt or derivative thereof. Accordingly, formulations of the present invention are mainly used in the physiological practice, particularly, in the medical sector for humans and animals. In this sense, the formulations are used as or in dosage forms, i.e. the formulations of the present invention have expedient forms that are appropriate for physiological practice, if necessary together with other excipients. Thus, the term “dosage form” refers to any dosage form that is suitable for administration of active substances to an organism, particularly to mammals, preferably humans, agricultural or domestic animals. Conventional dosage forms include, but are not limited to, (in alphabetical sequence) capsules, granules, pellets, powders, suspensions, suppositories, tablets. Granules comprise solid grains of the formulations of the present invention, wherein each grain represents an agglomerate of powder particles. Granules can have a mean corn size in the range of about 0.12 to about 2 mm, preferably about 0.2 to about 0.7 mm. Granules are preferably intended for oral use as dosage forms. The user can be offered single-dose preparations, for example, granules packed in a small bag (sachet), a paper bag or a small bottle, or multidose preparations which require appropriate measuring. However, in many cases, such granules do not represent the actual dosage form, but are intermediates in the manufacture of particular dosage forms, for example, tablet granules to be compressed to tablets, capsule granules to be packed into hard gelatin capsules, or instant granules or granules for oral suspension to be put in water before intake. As capsules, the formulations of the present invention are usually packed into a hard shell composed of two pieces fitted together or a soft, one-piece, closed shell, which may vary in shape and size. It is possible for the formulations of the present invention to be encased or enveloped or embedded in a matrix in suitable polymers, that is to say, microcapsules and microspherules. Hard and soft capsules comprise mainly of gelatin, while the latter can have a suitable content of plasticizing substances such as glycerol or sorbitol. Hard gelatin capsules are used to receive preparations of the present invention that have a solid consistency, for example granules, powder or pellets. Soft gelatin capsules are suitable for formulations with a semisolid consistency and, if required, also viscous liquid consistency. Pellets are granules of formulations of the present invention in the particle size ranging from about 0.5 to about 2.0 mm in diameter. Pellets having a narrow particle size distribution, preferably from about 0.8 to about 1.2 mm, and with an essentially round shape, are preferred. In semisolid preparations, formulations of the present invention are taken up in a suitable vehicle. Appropriate bases are known to those skilled in the art. Suppositories are solid preparations for rectal, vaginal or urethral administration. In order to be appropriate for this route of administration, formulations of the present invention in these drug forms must be taken up in suitable vehicles, for example, in fats which melt at body temperature, such as hard fat, macrogols, i.e. polyethylene glycols with molecular weights of about 1000 to about 3000 in various proportions, glycerol, gelatin and the like. Tablets are solid preparations for oral use. The meaning of oral within the framework of the present invention is, particularly, that of the term “peroral”, i.e. tablets for absorption or action of the active substance in the gastrointestinal tract. Particular embodiments include, but are not limited to, coated tablets, layered tablets, laminated tablets, tablets with modified release of active substance, matrix tablets, effervescent tablets or chewable tablets. The formulations of the present invention usually comprise at least a part of the necessary tablet excipients, such as binders, fillers, glidants and lubricants, and disintegrants. Tablets of formulations of the present invention may also, if necessary, comprise other suitable excipients. Excipients which assist tableting, for example lubricants and glidants, for example those mentioned above, with preference for flow regulators such as silica and/or lubricants such as magnesium stearate, particularly for facilitating compaction, can also be used herein. Coated tablets additionally comprise suitable coating materials, for example, film coating agents with coating aids, especially those mentioned below. Coated tablets include, but are not limited to, sugar-coated tablets and film-coated tablets. Powders are finely dispersed solids of formulations of the present invention with particle sizes usually of less than about 1 mm. The above statements about granules apply correspondingly. Preference is given according to the present invention to capsules packed with granules, powders or pellets of formulations of the present invention, instant granules and granules for oral suspension composed of formulations of the present invention with addition of masking flavors, and, in particular, tablets and coated tablets. The dosage forms of the present invention are usually packed in a suitable form. Pushout (blister) packs made of plastic and/or metal for solid dosage forms are frequently used. The present invention also relates to a process for producing a formulation of the present invention by mixing (blending) components i), ii) and optionally iii) to form a plastic mixture. Thus, to form the plastic mixture, at least two measures are necessary, first, the mixing (blending) of the components forming the mixture, and second, the plastification thereof, i.e. the conversion thereof into the plastic state. These steps may take place for one or more components or portions of components successively, intermeshingly, alternately or in another way. Accordingly, it is possible in principle for the conversion into the plastic state to take place concurrently during a mixing process, or for the mixture first to be mixed and then to be converted into the plastic state. A plurality of plastic mixtures differing in composition may be formed during a process and are mixed together and/or with other components or portions of components. For example, a premix of a portion of the components, e.g. excipient component and/or binder component, can be formulated to form granules, and the granules can then be converted, with the addition of other components, e.g. the active substance component, into a plastic mixture whose composition may correspond to that of the formulation. It is also possible for all the components to first be combined and then either converted into the plastic state at the same time as mixing or first mixed and then converted into the plastic state. The formation of a plastic mixture can take place by melting or, with additional input of mechanical energy, e.g. by kneading, mixing or homogenizing, below the melting point of the mixture. The plastic mixture is preferably formed at temperatures below about 220° C. The formation of the plastic mixture usually does not take place by one or more components being converted into a paste or partially dissolved with liquids or solvents, but takes place mainly or exclusively by thermal or thermal/mechanical action on the component(s), i.e. by thermal plastification. The plastic mixture is preferably formed by extrusion, more preferably, by melt extrusion. The plastification process steps can be carried out in a manner known per se, for example as described in EP-A-0 240 904, EP-A-0 337 256, EP-A-0 358 108, WO 97/15290 and WO 97/15291. The contents of these publications and, in particular, the statements about melt extrusion disclosed therein are incorporated herein by reference. In principle, there are two possible ways by which solubilization of the active substance can be achieved during melt extrusion. First, the extrusion process is carried out at a temperature that is higher than the melting point of the active substance and high enough for plastification of the binder. In this case, the molten active substance can be solubilized in the plastified binder by means of mixing and kneading which takes place during extrusion (method A). Second, if the solubility of the active substance is good, a solubilization in the plastified binder can take place without the need to melt the active substance. This situation is comparable to the dissolution of water-soluble compounds (e.g. sugar) in water which is also possible without the need for prior melting the compound (method B). Fenofibrate is an active substance with a relatively low melting point (approximately 80° C.) and therefore, a melting of the active substance can be expected during extrusion which is carried out normally at temperatures higher than 80 ° C. according to method A. Fenofibric acid has a melting point of 184° C. (Arzneimittel-Forschung 26, 885-909 (1976), see page 887) which is much higher than the melting point of fenofibrate. Therefore, solubilization of fenofibric acid in the binder(s) may take place according to method B. Moreover, method B could be advantageous even for processing fenofibrate in order to prevent any chemical degradation of fenofibrate at temperatures exceeding the melting point of fenofibrate. In addition to the melt extrusion technology, there are other known technologies for embedding active substances in binders in molecular dispersed form. The most common technique uses organic solvents where both the active substance(s) and the excipients (binders) are soluble. The solution of both compounds (active substances and binder(s)) are combined and then the solvent is removed completely. This process has a number of disadvantages because it requires the use of organic solvents which causes a lot of problems during manufacturing. Although possible, this is not the preferred process according to the present invention. In the case of low melting compounds like fenofibrate, the active substance can be placed in a beaker and heated together with the binder while the whole mixture is stirred. This technique does not use organic solvents but is based on a batch-process that requires much longer stirring and heating than in the case of a continuous process like melt extrusion. This means that the residence time of the drug at high temperature is much longer and thus increases the risk of possible degradation of both active substance(s) and binder(s). Furthermore, this process normally requires low-viscosity melts which are obtained by using e.g. PEG. Although possible, this is not the preferred process according to the present invention. It should be possible to convert the binder component into a plastic state in the complete mixture of all the components in the temperature range from about 30 to about 200° C., preferably about 40 to about 170° C. The glass transition temperature of the mixture should therefore be below about 220° C., preferably below about 180° C. If necessary, it can be reduced by conventional, physiologically acceptable plasticizing excipients. Examples of plasticizers include, but are not limited to, organic, preferably, involatile compounds, such as, for example, C7-C30-alkanols, ethylene glycol, propylene glycol, glycerol, trimethylolpropane, triethylene glycol, butandiols, pentanols such as pentaerythritol and hexanols, polyalkylene glycols, preferably having a molecular weight of from about 200 to about 1,000, such as, for example, polyethylene glycols (e.g. PEG 300, PEG 400), polypropylene glycols and polyethylene/propylene glycols, silicones, aromatic carboxylic esters (e.g. dialkyl phthalates, trimellitic esters, benzoic esters, terephthalic esters) or aliphatic dicarboxylic esters (e.g. dialkyl adipates, sebacic esters, azelaic esters, citric and tartaric esters, in particular triethylcitrate), fatty acid esters such as glycerol mono-, di- or triacetate or sodium diethyl sulfosuccinate. The concentration of plasticizer is, where present, generally about 0.5 to about 30, preferably about 0.5 to about 10% by weight based on the total weight of polymer and plasticizer and from about 0.1 to about 40, especially from about 0.5 to about 20 and more specifically from about 1 to about 10% by weight based on the total weight of the extruded formulation. The plasticizer can be added during extrusion by pumping the liquid directly into the extruder. Alternatively, the plasticizer can be granulated with one or all of the other solid components of the formulation prior to extrusion. The amount of plasticizer does not exceed about 30% by weight based on the total weight of polymer and plasticizer so that, in the area of solid forms, storage-stable formulations and dosage forms showing no cold flow are formed. Accordingly, it is preferred that the glass transition temperature of the final formulation be at least 40° C., preferably at least 50° C. The process of the present invention can advantageously be carried out at temperatures below about 220° C. and preferably below 180° C., but above room temperature (25° C.), preferably above about 40° C. A preferred temperature range for the extrusion of formulations of the present invention is about 80° C. to about 180° C. The process is carried out in a temperature range extending to about 40° C., preferably about 30° C., and most preferably about 20° C., upward or downward from the softening point of the mixture of the components. In certain cases, it may be beneficial to add components or portions of components as solution or suspension in a solvent. Particularly expedient ones are low molecular weight volatile solvents, e.g. water, C1-C6-monoalcohols and ethers thereof, esters of C1-C6-monoalkanols with C1-C6-carboxylic acids and alkanes. Another solvent that can be used is liquid CO2. Water-soluble active substances can be employed as aqueous solution or, optionally, be taken up in an aqueous solution or dispersion of the binder component or a portion thereof. Corresponding statements apply to active substances which are soluble in one of the solvents mentioned, if the liquid form of the components used is based on an organic solvent. The components to be employed according to the present invention may contain small amounts of solvent, e.g. because of hygroscopicity, trapped solvent or water of crystallization. The total solvent content of the plastic mixture is preferably less than about 15%, more preferably less than about 10%, and most preferably less than about 5%. The plastic mixture is preferably formed without the addition of a solvent, i.e. in particular by solvent-free melt extrusion. The components, i.e. active substance and/or binder and, where appropriate, other excipients, can first be mixed and then be converted into the plastic state and homogenized. This can be done by operating the apparatuses such as, but not limited to, stirred vessels, agitators, solids mixers etc. alternately. Sensitive active substances can then be mixed in (homogenized), preferably in “intensive mixers” in plastic phase with very small residence times. The active substance(s) may be employed as such, i.e. in particular in solid form, or as solution, suspension or dispersion. The plastification, melting and/or mixing takes place in an apparatus typically used for this purpose. Extruders or heatable containers with agitator, e.g. kneaders (like those of the type mentioned hereinafter) are particularly suitable. It is also possible to use as mixing apparatus those apparatuses that are employed for mixing in the field of plastics technology. Suitable apparatuses are described, for example, in “Mischen beim Herstellen and Verarbeiten von Kunststoffen”, R. Pahl, VDl-Verlag, 1986. Particularly suitable mixing apparatuses are extruders and dynamic and static mixers, and stirred vessels, single-shaft stirrers with stripper mechanisms, especially paste mixers, multishaft stirrers, especially PDSM mixers, solids mixers and, particularly mixer/kneader reactors (e.g. ORP, CRP, AP, DTB from List or Reactotherm from Krauss-Maffei or Ko-Kneader from Buss), trough mixers or internal mixers or rotor/stator systems (e.g. Dispax from IKA). The process steps of mixing and plastification, and particularly, the melting, can be carried out in the same apparatus or in two or more apparatuses operating separately from one another. The preparation of a premix can be carried out in one of the mixing apparatuses described above and normally used for granulation. Such a premix can then be fed directly into an extruder, for example, and then be extruded where appropriate with the addition of other components. It is possible in the process of the present invention to employ as extruders single screw machines, intermeshing screw machines or else multiscrew extruders, especially twin screw extruders that are suited to produce solid dispersions of a drug dissolved or dispersed in a polymer (cf. EP 0 580 860 A), corotating or counter-rotating and, where appropriate, equipped with kneading disks. If it is necessary in the extrusion to evaporate a solvent, the extruders are generally equipped with an evaporating section. Examples of extruders which can be used include, but are not limited to, those of the ZSK series from Werner & Pfleiderer. The mixing apparatus is charged continuously or batchwise, depending on its design, in a conventional way. Powdered components can be introduced in a free feed, e.g. via a weigh feeder. Plastic compositions can be fed in directly from an extruder or via a gear pump, which is particularly preferred if the viscosities and pressures are high. Liquid media can be metered in by a suitable pump unit. The mixture that has been obtained by mixing and converting the polymer component, the active substance component and, where appropriate, other excipients into the plastic state is pasty, of high viscosity or low viscosity (thermoplastic) and can therefore also be extruded. The glass transition temperature of the mixture is preferably below the decomposition temperature of all the components present in the mixture. The formulation of the present invention is suitable as a plastic mixture, where appropriate after cooling or solidification, preferably as extrudate, for all conventional processes for manufacturing conventional oral dosage forms, in particular drug forms. The present invention also relates to a process for producing dosage forms based on formulations of the present invention as described herein. Thus, the formulation can be produced by the above process and can be converted into the required dosage form where appropriate with the addition of other excipients. This can be done using shaping process measures such as by shaping the plastic mixture, such as by extrusion or melt extrusion, and shaping the plastic mixture, particularly, the extrudate, where appropriate after cooling or solidification, for example by granulation, grinding, compression, casting, injection molding, tableting under pressure, tableting under pressure with heat. It is also possible to convert a formulation into a desired dosage form by introducing it into suitable vehicles. It is also possible to process solid formulations into semisolid or liquid formulations through the addition of suitable vehicles. A large number of solid dosage forms can be manufactured in this way. For example, powders or granules can be produced by grinding or chopping the solidified or at least partly solidified plastic mixture, and can be either used directly for treatment or, where appropriate, with the addition of conventional excipients, further processed to the above dosage, in particular drug forms, especially tablets. Dosage forms are preferably shaped before solidification of the plastic mixture and result in a form that can be employed for treatment where appropriate after coating in a conventional way. The shaping to the dosage form before solidification can take place in a variety of ways depending on the viscosity of the plastic mixture, for example, by casting, injection molding, compression, or calendering. This is done by conveying the plastic mixture described above in the process according to the present invention to one or more shaping steps. The conveying can take place by pressing, pumping, e.g. with gear pumps, or, preferably, with an extruder. The plastic mixture can be formed in one or more, preferably one, extruder and conveyed by the latter or a downstream extruder to the shaping steps. It has proved to be advantageous in many cases to extrude on a downward incline and/or where appropriate to provide a guide channel for transporting the extrudate in order to ensure safe transport and prevent rupture of the extrudate. It may also be advantageous, depending on the number and compatibility of the active substances to be employed, to employ multilayer extrudates, for example coextrudates, as described in WO 96/19963, in the process of the present invention. Multilayer solid dosage forms can be produced by coextrusion, in which case a plurality of mixtures of one or more of the components described above are conveyed together into an extrusion die so that the required layer structure results. Different binders are preferably used for different layers. Multilayer dosage forms can comprise two or three layers. They may be in open or closed form, particularly as open or closed multilayer tablets. If the shaping takes place by coextrusion, the mixtures from the individual extruders or other units are fed into a common coextrusion die and extruded. The shape of the coextrusion dies depends on the required dosage form. Examples of suitable dies are those with a flat orifice, called slit dies, and dies with an annular orifice cross section. The design of the die depends on the formulation base used and, the binder component and the desired dosage form. The first shaping step takes place when the extrudate emerges from the extruder through suitably shaped dies, draw plates or other orifices, for example, through a breaker plate, a circular die or a slit die. This usually results in a continuous extrudate, particularly with a constant cross section, for example in the form of a ribbon or of a strand, preferably with a circular, oval, rounded or flat and broad cross section. Suitable downstream shaping steps for extrudates are, for example, cold cut, that is to say, the cutting or chopping of the extrudate after at least partial solidification, hot cut, that is, the cutting or chopping of the extrudate while still in the plastic form, or pinching off the still plastic extrudate in a nip device. It is possible with hot or cold cut to obtain, for example, granules (hot or cold granulation) or pellets. Hot granulation usually leads to dosage forms (pellets) with a diameter of from about 0.5 to about 3 mm, while cold granulation normally leads to cylindrical products with a length to diameter ratio of from about 1 to about 10 and a diameter of from about 0.5 to about 10 mm. It is possible in this way to produce monolayer but also, on use of coextrusion, open or closed multilayer dosage forms, for example oblong tablets, pastilles and pellets. The dosage forms can be provided with a coating by conventional methods in a downstream process step. Suitable materials for film coatings are the polymers mentioned as enteric binders. Further shaping steps may also follow, such as, for example, rounding off the pellets obtained by hot or cold cut using rounding-off devices as described in DE-A-196 29 753. It is particularly preferred for all of the shaping steps to be carried out on the still plastic mixture or still plastic extrudate. Besides hot cut, where appropriate with subsequent rounding off, a suitable process is one in which the plastic mixture is shaped to the dosage form in a molding calender. This is done by conveying a still plastic mixture or a still plastic extrudate to a suitable molding calendar. Suitable molding calenders usually have molding rolls and/or belts for the shaping, with at least one of the molding rolls and/or at least one of the belts having depressions to receive and shape the plastic mixture. It is preferred to use a molding calender with counter-rotating molding rolls, with at least one of the molding rolls having on its surface depressions to receive and shape the plastic mixture. Suitable molding calenders and devices containing molding rolls are generally disclosed for example in EP-A-0 240 904, EP-A-0 240 906 and WO 96/19962, and suitable belts and devices containing belts are generally disclosed for example in EP A-0 358 105, which are expressly incorporated herein by reference. The shaping of the still plastic mixture or still plastic extrudate preferably takes place at melt temperatures below about 220° C., more preferably below about 180° C. and most preferably below about 150° C., such as, for example, in the temperature ranges necessary to form the plastic mixture or at lower temperatures. If the shaping takes place at lower temperatures, it can take place at from about 5 to about 70° C., preferably about 10 to about 50° C. and most preferably about 15 to about 40° C. below the highest temperature reached on formation of the plastic mixture, but preferably above the solidification temperature of the plastic mixture. Preference is given to formulations and dosage forms obtainable by one of the processes described above. The formulations of the present invention, when used as a dosage form and thus providing an effective amount of active substance, are administered to the individual to be treated, including a human, domestic or agricultural animals. Whether such a treatment is indicated and what form it is to take depends on the individual case and may be subject to medical assessment (diagnosis) which includes the signs, symptoms and/or dysfunctions which are present, the risks of developing certain signs, symptoms and/or dysfunctions, and other factors. The formulations of the present invention are ordinarily administered together or alternately with other products in such a way that an individual to be treated receives a daily dose of about 50 mg to about 250 mg fenofibrate on oral administration. The formulations and dosage forms of the present invention are mainly used in pharmacy, for example in the pharmaceutical sector as lipid regulating agents. 2. Novel Salts of Fenofibric Acid In another aspect, the present invention relates to novel salts of fenofibric acid. In one embodiment, these novel salts are selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine. The structure of each of these salts is provided in Example 27, Table 3. The novel salts of the present invention are base addition salts that can be prepared by combining fenofibric acid and a base in a suitable solvent system and then mixing at an appropriate temperature. The determination of a suitable solvent system and appropriate temperature for preparing such salts can be readily determined by one of ordinary skill in the art. By way of example and not of limitation, Table 1 below shows examples of bases and solvents that can be used to make the novel salts of the present invention. TABLE 1 Base Solvent Salt Choline Hydroxide or Choline Isopropanol, Choline Chloride Methanol Diethanolamine Isopropanol Diethanolamine Tris(hydroxymethyl)aminomethane Isopropanol, Water Tromethamine (common name Tromethamine) Calcium Carbonate, Calcium Isopropanol, Calcium (2:1) Hydroxide or Calcium Chloride Water Ethanolamine Ethyl acetate Ethanolamine Piperazine Isopropanol, Water Piperazine(2:1) The inventors of the present invention have discovered that the novel salts of the present invention, namely, choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine, exhibit the desirable characteristic of photostability. The terms “photostability” and “photostable” are used interchangeably herein and refer to a lack of degradation induced by exposure to light from 300-800 nm under the conditions described in the “Guideline for the Photostability Testing of New Drug Substances and Products” (International Conference on Harmonization. Federal Register 1997; 65(95):27115-22, which is herein incorporated by reference) (hereinafter referred to as the “Guidelines”). As used herein, the term of “lack of degradation” means a recovery of 95% or greater on average, preferably a recovery of 97% or greater on average and most preferably, a recovery of 99% or greater on average of the novel salts of the present invention after exposure to light from 300-800 nm under the conditions described in the Guidelines described above and pursuant to the assay described in Example 28. The inventors of the present invention expect the novel salts of the present invention to exhibit photostability under less rigorous light conditions (exposures) and recognize that the novel salts may not exhibit photostability under more rigorous light conditions (exposures) than those described herein and in Example 28. The finding that the novel salts of the present invention are photostable was unexpected. Specifically, the inventors of the present invention discovered that the photostability of fenofibric acid and salts of fenofibric acid is unpredictable. More specifically, although the inventors of the present invention discovered that the novel salts of the present invention are photostable, the inventors found that certain forms of fenofibric acid as well as other salts of fenofibric acid (such as L-lysine and meglumine, which are discussed in more detail in the Examples) are not photostable. With respect to fenofibric acid, the inventors of the present invention found one form of fenofibric acid that is commercially available is photostable while another commercially available form of fenofibric acid is not photostable. Because the novel salts of the present invention are photostable, it is believed these salts and pharmaceutical formulations containing these salts will not exhibit unacceptable degradation or change (such as a change in the physicochemical properties of the salts) when exposed to light. The inventors recognize, however, that pharmaceutical formulations containing said novel salts may contain one or more pharmaceutically acceptable carriers or excipients or other ingredients that are photolabile even though the salts described herein (which would be the active pharmaceutical ingredient), are photostable. The photostability of the novel salts of the present invention facilitates their manufacturability and the manufacturability of pharmaceutical formulations containing these salts. Additionally, because the novel salts of the present invention are photostable, no special light-protected facility, storage or packing of these salts or pharmaceutical formulations should be required, provided that said formulations do not contain one or more other ingredients that are photolabile. As described in detail in the Examples, certain characterization and performance data, were examined for each of the above-described novel salts of the present invention. This data is summarized below in Table 2. TABLE 2 Novel Salts of Fenofibric Acid Melting Point Salt Range (° C.) PLM1 Choline 209-211 Crystalline Diethanolamine 142-144 Crystalline Tromethamine 198-204 Crystalline Calcium (2:1) 242-246* Crystalline Ethanolamine 121-123 Crystalline Piperazine (2:1) 215-217 Crystalline *Melting point of solid after dehydration and recrystallization peaks 1Polarized Light Microscopy In a second embodiment, the present invention relates to pharmaceutical formulations in a form of a molecular dispersion that comprise one or more of the novel salts of the present invention. The pharmaceutical formulations can be formulations such as those described under heading 1 herein and contain one or more of the novel salts of the present invention and at least one enteric binder. By way of example, and not of limitation, examples of the present invention will now be given. EXAMPLE 1 Fenofibrate (120 g corresponding to 15% w/w) and HP 55 S (hydropropylmethylcellulose phthalate, ShinEtsu, 672 g corresponding to 84% w/w) and colloidal silica (Aerosil 200, 8 g corresponding to 1% w/w) were blended for 4 minutes in a turbula blender. The powder mixture was then extruded in a twinscrew extruder (screw diameter 18 mm) with an feeding of 1.0 kg/h at a temperature of the melt at 165° C. A clear, transparent melt rope with a thickness of approximately 1.0 cm was extruded. This material was directly formed into tablets (oblong-shaped) by calendering between two co-rotating rollers. By this process clear, transparent tablets of high hardness were obtained having a tablet weight of approximately 550 mg. EXAMPLE 2 The tablets according to Example 1 were milled in laboratory mill and the resulting powder was analyzed by DSC between 20 and 250° C. (Mettler Toledo DSC-820; 8.45 mg in a closed pan at 10 K/min). No endothermic melting peaks were observed, indicating that the fenofibrate was present in the polymer matrix in non-crystalline form. EXAMPLE 3 The powder deriving from milling of the tablets according to Example 2 was analyzed by WAXS (wide angle x-ray scattering; Bruker AXS D-5005). There were no distinct peaks visible in the WAXS indicating that no crystalline fenofibrate was present in the formulation. EXAMPLE 4 The tablets according to Example 1 were analyzed with respect to possible drug degradation by HPLC according to the method described in Eur. pharm. for fenobibratum. The amount of the two known impurities according to USP were as follows: Impurity A=0.067%, Impurity B=0.071%. Although the extrusion was performed at a temperature far higher (165° C.) than the melting point of fenofibrate (approximately 80° C.) degradation took place to a very minor amount only. EXAMPLE 5 Drug dissolution from the tablets according to Example 1 was measured according to the USP paddle method at 37° C. in 900 ml aqueous solution of sodium dodecylsulfate (SDS, 0.05 mol/l) with a rotation speed of 75 rpm. Dissolution of the fenofibrate from the tablets was extremely slow in this medium. Only about 1% of the fenofibrate was liberated even after 90 minutes. EXAMPLE 6 The milled tablet material according to Example 2 was screened (63<x<500 microns). Hard gelatin capsules (size 00, mean total capsule weight 740 mg) were filled with a powder mixture containing the screened material (555 mg/capsule) together with mannitol (75 mg/capsule) and Aerosil 200 (5.55 mg/capsule). These capsules contained 83.25 mg fenofibrate. EXAMPLE 7 Drug dissolution from the capsules according to Example 6 was analyzed by the USP paddle method according to example 5 in 0.05 mol/l SDS solution. Fenofibrate release was shown to be faster compared to the unmilled tablets but was again relatively slow (16% dissolution after 90 minutes). EXAMPLE 8 Drug dissolution from the capsules according to Example 6 was analyzed by the USP paddle method at 37° C. in 900 ml phosphate buffer (pH 6.8) additionally containing sodium dodecylsulfate (SDS, 0.05 mol/1) with a rotation speed of 75 rpm. At this pH the dissolution was significantly faster compared to the unbuffered aqueous medium (91% dissolution after 90 minutes). EXAMPLE 9 Dissolution analysis was performed according to Example 8, but with a phosphate buffer having a pH of 7.2 together with 0.05 20 mol/l SDS. Drug dissolution was nearly 100% after 90 minutes. EXAMPLE 10 The capsules according to Example 6 were tested with respect to bioavailability in a dog model (n=4 dogs were used in this study, fasted). The marketed product (Tricor capsules, 67 mg fenofibrate/capsule) was used as reference. Plasma concentrations of fenofibric acid were determined by HPLC-MS. The results showed a remarkable increase in bioavailability for the formulation according to the present invention (approximately 4-fold increase in AUC) compared to the Tricor capsules. EXAMPLE 11 Fenofibrate (150 g corresponding to 15% w/w) and HP 50 (hydroxypropylmethylcellulose phthalate, ShinEtsu, 215 g corresponding to 21.5% w/w) and PVP (Kollidon K25, BASF, 625 g corresponding to 62.5% w/s) and colloidal silica (Aerosil 200, 10 g corresponding to 1% w/w) were blended for 4 minutes in a turbula blender. The powder mixture was then extruded in a twin-screw extruder (screw diameter 18 mm) with a feeding of 1.4 kg/h at a temperature of the melt at 149° C. A clear, transparent melt rope with a thickness of approximately 1.0 cm was extruded. This material was directly formed into tablets (oblong-shaped) by calendering between two co-rotating rollers. By this process opaque, translucent tablets of high hardness were obtained having a tablet weight of approximately 550 mg. EXAMPLE 12 Fenofibrate (150 g corresponding to 15% w/w) and HP 50 (hydroxpropylntethylcellulose phthalate, ShinEtsu, 190 g corresponding to 19% w/w), PVP (Kollidon K25, BASF, 600 g corresponding to 60% w/w) and polyoxyethylated oleic glyceride (Labrafil M 1944 CS, Gattefosse, 50 g corresponding to 5% w/w) and colloidal silica (Aerosil 200, 10 g corresponding 1% w/w) were blended for 4 minutes in a turbula blender. The liquid compound (Labrafil M 1944 CS) was granulated with the PVP prior to extrusion. The powder mixture including all ingredients was then extruded in a twin-screw extruder (screw diameter 18 mm) with a feeding rate of 2.0 kg/h at a temperature of the melt at 145° C. A clear, transparent melt rope with a thickness of approximately 1.0 cm was extruded. This material was directly formed into tablets (oblong-shaped) by calendering between two co-rotating rollers. By this process opaque, translucent tablets of high hardness were obtained having a tablet weight of approximately 550 mg. EXAMPLE 13 Fenofibric acid (120 g corresponding to 15% w/w) and HP 55 (hydroxypropylmethylcellulose phthalate, ShinEtsu, 672 g corresponding to 85% w/w) and colloidal silica (Aerosil 200, 8 g corresponding to 1% w/w) were blended and extruded as outlined in Example 1. A clear drug-containing melt was obtained. Transparent tablets with high hardness were obtained having a tablet weight of approximately 550 mg (corresponding to 82.5 mg fenofibric acid per tablet). EXAMPLE 14 The crystallinity of the drug in the melt-extruded samples of Example 13 were analyzed with respect to DSC and WAXS according to Examples 2 and 3. No crystalline drug material was detected neither by DSC nor by WAXS. EXAMPLE 15 Hard gelatin capsules were prepared according to example 6 containing milled extrudate (63<x<500 microns) of the melt-extrudate of Example 13. These capsules contained 73.79 mg fenofibric acid (mean) corresponding to 83.53 mg fenofibrate (f=1.132), 413.23 mg HP 66 (mean), 134.63 mg mannitol (mean) and 11.57 mg Aerosil 200 (mean). The total weight of these capsules was 747.1 mg (mean). EXAMPLE 16 The bioavailability o f the capsule formulation according to Example 15 (containing fenofibric acid) was tested with respect to bioavailability in the dog model in comparison to the capsule formulation according to example 6 (which contains fenofibrate). The bioavailability of the fenofibric acid-containing capsule (according to Example 15) was shown to be twice as high as in the case of the fenofibrate-containing capsule formulation (according to Example 6). EXAMPLE 17A Method for Making Choline Salt Fenofibric acid (10.0 g, 0.0314 mol) was suspended in 100 mL isopropanol and the mixture heated to 65° C. A solution of choline hydroxide in methanol (8.58 g, 45 wt %, 0.0319 mol) was diluted with 20 mL isopropanol and approximately two thirds of the solution was added to the fenofibric acid suspension. Optionally, seed crystals of the choline salt can be added to expedite the formation of crystals. The remaining one third of the choline hydroxide solution was added followed by a 15 mL rinse of the addition funnel with isopropanol. The product crystallized out of solution and the slurry was mixed at 65° C. for 0.5 hour, cooled to 20° C. over 5 hours, and then mixed at 20° C. overnight. The product was filtered off and rinsed with 30 mL of isopropanol. The solid was dried in a vacuum oven at 35° C. with a nitrogen purge for approximately 24 hours. The dry weight of solid was 11.83 g, or 89.4% yield. 1H NMR (400 MHz, D2O) δ 7.75 (m, 2H), 7.70 (m, 2H), 7.55 (m, 2H), 6.93 (m, 2H), 4.03 (m, 2H), 3.49 (m, 2H), 3.17 (s, 9H), 1.59 (s, 6H); Anal. Calcd. for C22H28ClNO5: C, 62.63; H, 6.69; N, 3.32; Cl, 8.40. Found: C, 62.70; H, 7.12; N, 3.36; Cl, 8.23. EXAMPLE 17B Alternate Method for Making Choline Salt Fenofibric acid (10.0 g, 0.0314 mol) and sodium bicarbonate (2.64 g, 0.0314 mol) were suspended in 75 mL of methanol and the mixture heated to 55° C. to dissolve the solids. A solution of choline chloride (4.40 g, 0.0315 mol) in 15 mL of methanol was added. The solution was filtered to remove the precipitated sodium chloride, and the filter rinsed with 20 mL of methanol. The filtrate was diluted with 40 mL of isopropanol and concentrated to a volume of approximately 120 mL. The solution was filtered and the filter rinsed with 20 mL of isopropanol. The filtrate was concentrated to a solid residue weighing 14 g. The residue was suspended in 70 mL of isopropanol and heated to 55° C. for 0.5 hour, cooled to 22° C. over 5 hours, and mixed at 22° C. for approximately 16 hours. The product was filtered off and rinsed with 35 mL of isopropanol. The solid was dried in a vacuum oven at 50° C. with a nitrogen purge for 5 hours. The dry weight of solid was 12.98 g, or 98.1% yield. EXAMPLE 18A Method for Making Tromethamine Salt Fenofibric acid (10.0 g, 0.0314 mol) and tris(hydroxymethyl)aminomethane (or tromethamine) (3.8 g, 0.031 mol) were suspended in 120 mL isopropanol and the mixture heated to 65° C. The product crystallized out of solution. The slurry was mixed at 65° C. for 1.0 hour, cooled to 20° C. over 5 hours, and then mixed at 20° C. for 0.5 hour. The product was filtered off and rinsed with 25 mL of isopropanol. The solid was dried in a vacuum oven at 35° C. with a nitrogen purge for approximately 20 hours. The dry weight of solid was 13.66 g, or 99.0% yield. 1H NMR (400 MHz, CD3OD) δ 7.69 (m, 2H), 7.68 (m, 2H), 7.53 (m, 2H), 6.95 (m, 2H), 3.69 (s, 6H), 1.59 (s, 6H); Anal. Calcd. for C21H26ClNO7: C, 57.34; H, 5.96; N, 3.18; Cl, 8.06. Found: C, 57.15; H, 5.97; N, 3.06; Cl, 8.07. EXAMPLE 18B Alternate Method for Making Tromethamine Salt Fenofibrate (33.0 g, 0.0914 mol) was suspended in 33 mL of isopropanol and aqueous NaOH was added (64.9 g of a 8.47% solution, 5.50 g NaOH, 0.138 mol, 1.5 eq). The mixture was heated to reflux for 2.75 h, and then cooled to approximately 35° C. The solution was diluted with 46 g of water, and then a solution of tromethamine (12.2 g, 0.101 mol, 1.1 eq) in 33 g of water was added. A solution of hydrochloric acid (52.0 g of a 10.3% solution, 5.34 g of HCl, 0.146 mol, 1.6 eq) was added and the product crystallized from solution. The slurry was heated to 50° C. for 1 h, cooled to 22° C. over 3 h, and mixed at 22° C. approximately 16 h. The product was filtered and rinsed with 100 g of water. The product was dried in a vacuum oven at 50° C. with a nitrogen purge to a constant weight. The dry weight was 40.23 g, or 96.4% yield. EXAMPLE 19A Method for Making Calcium Salt Fenofibric acid (550.3 g, 1.726 mol) was suspended in 1.5 kg of water. An aqueous NaOH solution was added (137.2 g of a 50.5% solution, 69.29 g NaOH, 1.732 mol, 1.0 eq.), and the addition funnel rinsed with 50 g of water. The solution was filtered, the transfer aided with a 400 g rinse of water, and the filtrate heated to 70° C. An aqueous solution of calcium chloride (126.9 g of calcium chloride dihydrate in 300 g of water, 0.8631 mol, 0.5 eq) was added over 30 minutes, and the addition funnel rinsed with 60 g of water. The product crystallized out of solution during the addition of calcium chloride. The slurry was diluted with 5.3 kg of water and 2 L of isopropanol and mixed for approximately 1 h at 50° C., cooled to 22° C. and mixed overnight. The slurry was diluted with 800 g of water and 800 mL of isopropanol, and the product was then filtered and rinsed with 2.5 kg of water, and 750 mL of isopropanol. The solid was dried in a vacuum oven at 60° C. with a nitrogen purge for approximately 60 h. The weight of solid after drying was 602.6 g, with 4.3 weight % of water by Karl Fischer analysis. Adjusting for the water content the yield was 98.9%. 1H NMR (400 MHz, CD3OD) δ 7.68 (m, 8H), 7.50 (m, 4H), 6.96 (m, 4H), 1.60 (s, 12H); Anal. Calcd. for C34H28CaCl2O: C, 60.45; H, 4.18; Cl, 10.50. Found: C, 59.91; H, 4.1 1; Cl, 10.65. EXAMPLE 19B Alternate Method for Making Calcium Salt Fenofibric acid (4.0 g, 0.013 mol) was suspended in 100 mL isopropanol and the mixture heated to 45° C. A suspension of calcium carbonate (0.628 g, 0.00627 mol) in 40 mL water was added, rinsing the addition funnel with 10 mL of water. The mixture was heated to 60° C. and then cooled to 45° C. and the product crystallized out of solution. The mixture was heated to 65° C., cooled to 22° C. over 2.5 hours, and then mixed at 22° C. for 1 hour. The product was filtered off and rinsed with 30 mL of isopropanol. The solid was dried in a vacuum oven at 40° C. with a nitrogen purge for approximately 20 hours, and then at 80° C. for 3 hours. The dry weight of solid was 3.87 g, with 3.2 weight % of water by Karl Fischer analysis. Adjusting for the water content the yield was 88.4%. EXAMPLE 20 Method of Making Diethanolamine Salt Fenofibric acid (10.0 g, 0.0314 mol) was suspended in 100 mL of isopropanol and the mixture heated to 65° C. A solution of diethanolamine (3.3 g, 0.031 mol) in 20 mL isopropanol was prepared and approximately two thirds of the solution was added to the fenofibric acid suspension. Optionally, seed crystals of the diethanolamine salt may be added to expedite the formation of crystals. The remaining one third of the diethanolamine solution was added with a 15 mL rinse of the addition funnel with isopropanol. The mixture was cooled to 50° C. and product crystallized out of solution. The slurry was heated to 65° C. and mixed for 0.5 hour, cooled to 20° C. over 5 hours, and then mixed at 20° C. for 1 hour. The product was filtered off and rinsed with 30 mL of isopropanol. The solid was dried in a vacuum oven at 35° C. with a nitrogen purge for approximately 24 hours. The dry weight of solid was 12.22 g or 91.9% yield. 1H NMR (400 MHz, D2O) δ 7.74 (m, 2H), 7.69 (m, 2H), 7.54 (m, 2H), 6.92 (m, 2H), 3.84 (m, 4H), 3.22 (m, 4H), 1.59 (s, 6H); Anal. Calcd. for C21H26ClNO6: C, 59.50; H, 6.18; N, 3.30; Cl, 8.36. Found: C, 59.36; H, 6.42; N, 3.18; Cl, 8.38. EXAMPLE 21 Method of Making L-Lysine Salt Fenofibric acid (10.0 g, 0.0314 mol) and L-Lysine (4.60 g, 0.0315 mol) were suspended in 125 mL of ethanol. The mixture was heated to 65° C. Optionally, seed crystals of the L-lysine salt can be added to expedite the formation of crystals. The mixture slowly cooled to 22° C. While mixing at 22° C. overnight, the product crystallized out of solution. The slurry was heated to 50° C. for 1 hour and then cooled to 22° C. The product was filtered off and rinsed with 35 mL of ethanol. The solid was dried in a vacuum oven at 40° C. with a nitrogen purge for approximately 20 hours. The dry weight of solid was 12.24 g, or 83.9% yield. 1H NMR (400 MHz, D2O) δ 7.73 (m, 2H), 7.68 (m, 2H), 7.53 (m, 2H), 6.92 (m, 2H), 3.71 (t, J=6.1, 1H), 2.99 (m, 2H), 1.87 (m, 2H), 1.69 (m, 2H), 1.58 (s, 6H), 1.44 (m, 2H); Anal. Calcd. for C23H29ClN2O6: C, 59.42; H, 6.29; N, 6.03; Cl, 7.63. Found: C, 59.26; H, 6.32; N, 6.11; Cl, 7.70. EXAMPLE 22A Method of Making Piperazine Salt Fenofibric acid (10.0 g, 0.0314 mol) was suspended in 100 mL of isopropanol and the mixture heated to 65° C. A solution of piperazine (1.4 g, 0.016 mol) in 20 mL isopropanol was prepared with heating and added to the fenofibric acid suspension, with a 10 mL rinse of the addition funnel with isopropanol. The product crystallized during addition of the piperazine solution. The slurry was mixed at 65° C. for 0.8 hours, cooled to 20° C. over 4 hours, and then mixed at 20° C. for 1.5 hours. The product was filtered off and rinsed with 30 mL of isopropanol. The solid was dried in a vacuum oven at 40° C. with a nitrogen purge for approximately 20 hours. The dry weight of solid was 11.00 g or 96.9% yield. 1H NMR (400 MHz, CD3OD) δ 7.70 (m, 8H), 7.53 (m, 4H), 6.95 (m, 4H), 3.12 (s, 8H), 1.62 (s, 12H); Anal. Calcd. for C38H40Cl2N2O8: C, 63.07; H, 5.57; N, 3.87; Cl, 9.80. Found: C, 63.01; H, 5.53; N, 3.79; Cl, 9.78. EXAMPLE 22B Alternate Method for Making Piperazine Salt Fenofibrate (33.0 g, 0.0914 mol) was suspended in 33 mL of isopropanol and aqueous NaOH was added (64.9 g of a 8.47% solution, 5.50 g NaOH, 0.138 mol, 1.5 eq). The mixture was heated to reflux for 4 h, and then cooled to approximately 35° C. The solution was diluted with 46 g of water, and then a solution of piperazine (4.3 g, 0.050 mol, 1.1 eq) in 33 g of water was added. A solution of hydrochloric acid (53.1 g of a 10% solution, 5.31 g of HCl, 0.146 mol, 1.6 eq) was added and the product crystallized from solution. The slurry was heated to 50° C. for 1 h, cooled to 22° C. over 3 h, and mixed at 22° C. approximately 16 h. The product was filtered and rinsed with 100 g of water. The product was dried in a vacuum oven at 50° C. with a nitrogen purge for approximately 16 hours. The dry weight was 33.0 g, or 99.7% yield from fenofibrate. EXAMPLE 23 Method for Making Ethanolamine Salt Fenofibric acid (10.0 g, 0.0314 mol) was suspended in 100 mL of ethyl acetate. A mixture of ethanolamine (1.97 g, 0.323 mol) in 15 mL of ethyl acetate was added, rinsing with 10 mL of ethyl acetate. Optionally, seed crystals of the ethanolamine salt can be added to expedite the formation of crystals. The product crystallized out of solution. The slurry was heated to 50° C. for 0.3 hour, cooled to 20° C. over 1.5 hours, and then mixed at 20° C. for 1 hour. The product was filtered off and rinsed with 50 mL of ethyl acetate. The solid was dried in a vacuum oven at 40° C. with a nitrogen purge for approximately 4 hours. The dry weight of solid was 11.70 g, or 98.2% yield. 1H NMR (400 MHz, D2O) δ 7.75 (m, 2H), 7.71 (m, 2H), 7.55 (m, 2H), 6.93 (m, 2H), 3.79 (m, 2H), 3.11 (m, 2H), 1.59 (s, 6H); Anal. Calcd. for C19H22ClNO5: C, 60.08; H, 5.84; N, 3.69; Cl, 9.33. Found: C, 59.85; H, 6.03; N, 3.62; Cl, 9.30. EXAMPLE 24 Method for Making Meglumine Salt Fenofibric acid (10.0 g, 0.0314 mol) and N-methyl-D-glucamine (or meglumine) (6.12 g, 0.0313 mol) were suspended in 125 mL of ethyl acetate. The mixture was heated to 50° C., and 30 mL ethanol was added. Optionally, seed crystals of the meglumine salt can be added to expedite the formation of crystals. The solution was heated to 65° C. and then cooled to 22° C. The solution was diluted with 30 mL of heptane, heated to 55° C. and cooled slowly to 22° C. While mixing at 22° C. overnight the product crystallized out of solution. The product was filtered off and rinsed with a mixture of 30 mL of ethyl acetate, 5 mL of ethanol and 5 mL of heptane. The solid was dried in a vacuum oven at 40° C. with a nitrogen purge for approximately 4 hours. The dry weight of solid was 14.72 g, or 91.3% yield. 1H NMR (400 MHz, D2O) δ 7.69 (m, 2H), 7.64 (m, 2H), 7.50 (m, 2H), 6.90 (m, 2H), 4.07 (m, 1H), 3.79 (m, 2H), 3.74 (m, 1H), 3.62 (m, 2H), 3.18 (m, 2H), 2.74 (s, 3H), 1.58 (s, 6H); Anal. Calcd. for C24H32ClNO9: C, 56.08; H, 6.28; N, 2.73; Cl, 6.90. Found: C, 55.81; H, 6.26; N, 2.69; Cl, 6.85. EXAMPLE 25 Method of Making Sodium Salt Fenofibric acid (4.0 g, 0.013 mol) was suspended in 40 mL of isopropanol and the mixture heated to 65° C. A solution of sodium hydroxide (0.97 g, 50.7 wt %, 0.012 mol) in water was added, rinsing with 1 mL of water. The mixture was diluted with a total of 180 mL of isopropanol and concentrated by vacuum distillation to a volume of 60 mL. The product crystallized out of solution and the mixture was heated to 65° C. and diluted with 40 mL of isopropanol. The slurry was mixed at 65° C. for 0.5 hour, and then cooled to 22° C. The product was filtered off and rinsed with 80 mL of isopropanol. The solid was dried in a vacuum oven at 80° C. with a nitrogen purge for approximately 1.5 hours. The dry weight of solid was approximately 2 g, or 50% yield. 1H NMR (400 MHz, D2O) δ 7.67 (m, 2H), 7.62 (m, 2H), 7.49 (m, 2H), 6.89 (m, 2H), 1.57 (s, 6H); Anal. Calcd. for C17H]4ClNaO4: C, 59.92; H, 4.14; Cl, 10.40. Found: C, 59.67; H, 4.15; Cl, 10.48. EXAMPLE 26A Method for Making Fenofibric Acid Form I Fenofibrate (350. g, 0.970 mol) was suspended in 2 L of isopropanol. A solution of NaOH (77.6 g NaOH, 1.94 mol, 2 eq) in 1.8 L of water was added and the mixture heated to reflux for 2.7 hours. The solution was cooled to approximately 4° C. A solution of hydrochloric acid (697.2 g of a 10.03% solution, 69.90 g of HCl, 1.917 mol, 2 eq) was added maintaining the temperature at less than 5° C., and the product crystallized from solution. The crystallization can be optionally seeded with Form I fenofibric acid after approximately 50% of the hydrochloric acid is added. The slurry was warmed to 20° C. and mixed for 0.8 hours. The product was filtered, rinsed with 600 mL of 2:1 water:isopropanol, and then rinsed with 300 mL of water. The product was dried in a vacuum oven at 40° C. with a nitrogen purge for 14 hours, and then dried at 60° C. for 24 hours. The dry weight was 300.6 g, or 97.2% yield. 1H NMR (400 MHz, CD3OD) δ 7.72 (m, 2H), 7.71 (m, 2H), 7.52 (m, 2H), 6.95 (m, 2H), 1.66 (s, 6H); Anal. Calcd. for C17H15ClO4: C, 64.06; H, 4.74; N, Cl, 11.12. Found: C, 63.94; H, 4.64; Cl, 11.13. EXAMPLE 26B Method for Making Fenofibric Acid Form II Fenofibrate (200.0 g, 0.5543 mol) was suspended in 900 mL of isopropanol. A solution of NaOH (33.0 g NaOH, 0.825 mol, 1.49 eq) in 400 mL of water was added and the mixture heated to reflux for 2 hours. The solution was cooled to approximately 75° C. A solution of hydrochloric acid (652 g of a 5.0% solution, 32.8 g of HCl, 0.894 mol, 1.6 eq) was added maintaining the temperature above 55° C., and the product crystallized from solution. The slurry was cooled to 28° C. over 3.5 hours. The product was filtered and rinsed twice with 500 mL of water. The product was dried in a vacuum oven at 60° C. with a nitrogen purge for approximately 16 hours. The dry weight was 170.7 g, or 96.6% yield. EXAMPLE 27 Characterization of the Salts of Fenofibric Acid Choline, diethanolamine, tromethamine, sodium, calcium, ethanolamine, meglumine, L-lysine and piperazine salts were prepared as described in Examples 17-25. Fenofibric acid form I was made as described in Example 26A and can be purchased from Labo Test, Niederschoena, Germany. Fenofibric acid form II was obtained from Synkem, Chenove Cedex, France and can be made as described in Example 26B and can also be made pursuant to U.S. Pat. No. 4,072,705, which is hereby incorporated by reference. The melting point was determined using differential scanning calorimetry (either Model 2920 or Q1000 differential scanning calorimeter, TA Instruments, New Castle, Del.). Approximately 1-3 mg of material was placed in an aluminum pan. The sample was heated at 10° C./minute. The melting point range was determined from the DSC thermogram as the extrapolated onset temperature to the peak temperature. Tables 3 below lists the structures and molecular weight of each of the choline, diethanolamine, tromethamine, sodium, calcium, ethanolamine, meglumine, L-lysine, and piperazine. The crystallinity of the compounds was confirmed by polarized light microscopy. The polarized light microscopy was determined using the procedures outlined in the USP, Volume 25, Chapter 776, published by the United States Pharmacopeia (2002). Table 4 below lists the melting point and crystallinity for choline, diethanolamine, tromethamine, sodium, calcium, ethanolamine, meglumine, L-lysine, and piperazine as well as for fenofibric acid forms I and II. TABLE 3 Salt Salt Structure M.W. Choline 421.91 Diethanolamine 423.89 Tromethamine 439.89 Sodium 340.73 Calcium (2:1) 675.56 Ethanolamine 379.83 Meglumine 513.96 L-Lysine 464.94 Piperazine (2:1) 723.64 TABLE 4 Melting Point Salt/Form Range (° C.) PLM1 Choline 209-211 Crystalline Diethanolamine 142-144 Crystalline Tromethamine 198-204 Crystalline Sodium 236 Crystalline Calcium (2:1) 242-246* Crystalline Ethanolamine 121-123 Crystalline Meglumine 114-116 Crystalline L-Lysine 163-169 Crystalline Piperazine (2:1) 215-217 Crystalline Fenofibric Acid Form I 175-176 Crystalline Fenofibric Acid Form II 184-185 Crystalline *Melting point of solid after dehydration and recrystallization peaks 1Polarized Light Microscopy EXAMPLE 28 Solid State Photostability of Fenofibric Acid and its Salts About 1-4 mg of each of fenofibric acid form I, fenofibric acid form II, choline, diethanolamine, tromethamine, sodium, calcium, ethanolamine, meglumine, L-lysine, and piperazine was weighed into separate 4 mL clear glass vials. The methods for making each of these salts is described in Example 17A (choline), Example 18A (tromethamine), Example 19A (calcium), Example 20 (diethanolamine), Example 21 (L-lysine), Example 22B (piperazine), Example 23 (ethanolamine), Example 24 (meglumine) and Example 25 (sodium). Fenofibric acid form I was made as described in Example 26A and can be purchased from Labo Test, Niederschoena, Germany. Fenofibric acid form II was obtained from Synkem, Chenove Cedex, France and can be made as described in Example 26B and can also be made pursuant to U.S. Pat. No. 4,072,705, which is hereby incorporated by reference. The vials were sealed with PTFE lined caps, and divided into 2 groups with at least three replicates in each group. The first group was wrapped in aluminum foil to serve as controls. Samples and controls were placed inside a light exposure chamber (SUNTEST CPS+, Atlas Material Testing Technology, LLC, Chicago, Ill.) where temperature was maintained at 25° C. Exposure conditions were selected to follow the “Guideline for the Photostability Testing of New Drug Substances and Products” (International Conference on Harmonization. Federal Register 1997; 65(95):27115-22.) The light source is a xenon arc lamp filtered through window glass to mimic indoor daylight (ISO 10977 ID65). The total light exposure (300-800 nm wavelength) was 19460 kJ/m2 over 18 hours. At the end of the light exposure, all samples and controls were removed and analyzed by HPLC using the conditions shown below in Table 6. The photostability results are shown below in Table 5. TABLE 5 Recovery %a Sample (±Standard Deviation, n = 3) Fenofibric acid, Form I 40.9 ± 8.3 Fenofibric acid, Form II 99.0 ± 0.6 Choline salt 97.4 ± 3.5 Calcium salt 98.8 ± 1.6 Diethanolamine salt 98.8 ± 0.5 Sodium salt 98.0 ± 2.2 Meglumine salt 85.7 ± 2.6 L-Lysine salt 94.4 ± 2.2 Ethanolamine salt 98.1 ± 1.8 Tromethamine salt 98.6 ± 1.2 Piperazine salt 100.4 ± 1.0 aNormalized with controls as 100%. TABLE 6 HPLC Conditions Column: Waters Symmetry Shield (Available from Waters, Milford, Mass.) RP18, 5 μm, 250 mm × 4.6 mm Flow Rate: approximately 1 mL/min Injection Volume: 10 μL Column Temperature: approximately 35° C. Detector/Wavelength: UV at 286 nm Mobile Phase: ACN:Acidified Water, pH 2.5 (60:40) Run time: 60 minutes One skilled in the art would readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The molecular complexes and the methods, procedures, treatments, molecules, specific compounds described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. All patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Thus, for example, in each instance herein any of the terms “comprising,” “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group. For example, if X is described as selected from the group consisting of bromine, chlorine, and iodine, claims for X being bromine and claims for X being bromine and chlorine are fully described.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Fenofibrate is a well-known lipid regulating agent which has been commercially available for a long time. Fenofibrate is usually orally administered. After its absorption, which is known to take place in the duodenum and other parts of the gastrointestinal tract, fenofibrate is metabolized in the body to fenofibric acid. In fact, fenofibric acid represents the active ingredient of fenofibrate. In other words, fenofibrate is a so-called prodrug which is converted in vivo to the active molecule. After oral administration of fenofibrate, fenofibric acid is found in plasma. U.S. Pat. Nos. 4,179,515 and 4,235,896 disclose the preparation of fenofibric acid and also describe acid addition salts of amine containing analogs. U.S. Pat. No.4,372,954 discloses the moroxydine salt of fenofibric acid as useful for the inhibition of platelet aggregation and for lowering fibrinogen. Spanish patent ES 474039 discloses the use of the cinnarizine-salt of fenofibric acid for the reduction of triglyceride levels and the sodium salt of fenofibric acid (in solution) has also been disclosed (Bosca et al., Photochemistry and Photobiology, 1999, 70(6), 853-857). Fenofibrate is known to be nearly insoluble in water and requires special pharmaceutical formulations in order to ensure good bioavailability, especially after oral administration. Accordingly, fenofibrate has been prepared in several different formulations, (see WO 00/72825 and the citations provided therein, such as U.S. Pat. Nos. 4,800,079, 4,895,726, 4,961,890, EP-A 0 793 958 and WO 82/01649). Additional formulations of fenofibrate are described in WO 02/067901 and citations provided therein, such as U.S. Pat. Nos. 6,074,670 and 6,042,847. The fenofibrate products currently on the market involve a formulation comprising a micronized drug substance in capsules and/or tablets. However, the insolubility of fenofibrate in water may still negatively impact the in vivo performance of the product. One approach to mitigate the bioavailability issue is to render the crystalline drug amorphous, leading to accelerated drug release. However, recrystallization of amorphous materials could occur, especially for insoluble molecules such as fenofibrate. Thereupon, one object of the present invention is to provide pharmaceutical formulations that make fenofibric acid sufficiently bioavailable and prevent recrystallization of the active substance. This object is achieved by formulations that comprise fenofibric acid, a physiologically acceptable salt or a physiologically acceptable derivative thereof that is embedded in an enteric binder. It is another object of the present invention to provide novel salts of fenofibric acid that result in a product having improved photostability when compared to fenofibric acid and other salts of fenofibric acid.
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<SOH> SUMMARY OF THE INVENTION <EOH>In one aspect, the present invention relates to a pharmaceutical formulation comprising: i) fenofibric acid, or a physiologically acceptable salt or derivative thereof and optionally, other active ingredients (which is collectively referred to as the “active substance component); ii) a binder component comprising at least one enteric binder; and optionally, iii) other physiologically acceptable excipients. The physiologically acceptable derivative of fenofibric acid can be fenofibrate. Additionally, the fenofibric acid, physiologically acceptable salt or derivative thereof can be present in the formulation as a molecular dispersion. The binder employed in the above-described formulation can be an enteric polymer, such as those selected from the group consisting of: hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate succinate, carboxymethylethylcellulose, cellulose acetate phthalate, cellulose acetate trimellitate and carboxymethylcellulose sodium. Additionally, the enteric polymer can be a copolymer, such as a copolymer of (meth)acrylic acid and at least one alkyl (meth)acrylic acid ester. The alkyl (meth)acrylic acid ester can be methyl methacrylate. The copolymer can have a ratio of free carboxyl groups to esterified carboxyl groups of about 2:1 to 1:3, preferably, about 1:1. The other physiologically acceptable excipients can be a flow regulator, such as a highly dispersed silica gel. Preferably, the above-described formulation comprises i) about 5 to about 60% by weight, preferably about 7 to about 40% by weight and most preferably, about 10 to about 30% by weight of active substance component; ii) about 20 to about 95% by weight, preferably about 30 to about 90% by weight and most preferably, about 40 to about 80% by weight, of a binder component; iii) 0 to about 75% by weight, preferably about 1 to about 60% by weight and most preferably, about 5 to about 40% by weight, of other physiologically acceptable excipients. It is preferred that the enteric binder employed in the above-described formulation comprise about 5 to about 95% by weight, more preferably from about 10 to about 70% by weight and most preferably, about 30 to about 60% by weight of the binder component (ii). Moreover, the content of the active substance component (i) relative to the binder component (ii) is from about 1 to about 50% by weight, preferably about 10 to about 40% by weight and most preferably about 20 to about 30% by weight. The above-described formulation can be obtained by melt extrusion of a mixture comprising fenofibric acid, a physiologically acceptable salt or derivative thereof, binder and optionally, other active substances and/or physiologically acceptable excipients. The above-described formulation can be used in a method of oral administration of fenofibric acid, a physiologically acceptable salt or derivative thereof. This method involves the step of administering the above-described formulation and optionally, other excipients, as a dosage form to a mammal, preferably a human. In another aspect, the present invention relates to a salt of fenofibric acid selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine. In yet another embodiment, the present invention relates to a pharmaceutical formulation in the form of a molecular dispersion comprising a salt of fenofibric acid that is selected from the group consisting of choline, ethanolamine, diethanolamine, piperazine, calcium and tromethamine and a binder component comprising at least one enteric binder. Preferably, said formulation comprises about 5 to about 60% by weight of one of said novel salts and about 20 to about 95% by weight of a binder component. detailed-description description="Detailed Description" end="lead"?
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20040630
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20070821
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20050707
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72050.0
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BADIO, BARBARA P
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SALTS OF FENOFIBRIC ACID AND PHARMACEUTICAL FORMULATIONS THEREOF
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
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10,880,888
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ACCEPTED
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Method and system for mapping between logical data and physical data
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The mapping system maps a physical table of a database to a logical table representing a logical view of the database that integrates standard columns and custom columns. The physical table includes a standard table with standard columns and a custom table with custom columns. The custom table may be implemented as a pivot table. The mapping system provides a map between standard and custom columns and logical columns. The physical table may include multiple standard tables. The mapping system allows for individual standard tables to be updated, rather than updating all the columns across all the standard tables for a row.
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1. A method in a computer system for providing a view of data, the method comprising: providing physical data having standard and custom data, the standard data having entries with data for standard fields, the custom data having data for custom fields, the custom fields being represented by pivot data; providing a map between standard and custom fields and logical fields of logical data; providing a result set containing physical data from a standard field and a custom field; and organizing the physical data of the result set into logical data using the provided map. 2. The method of claim 1 wherein the physical data, the custom data, the pivot data, and the logical data are represented as tables, their entries corresponding to rows of the tables and the fields corresponding to columns of the tables. 3. The method of claim 2 where each row of the pivot table identifies a custom column, a row of the physical table, and data for the custom column of that row of the physical table. 4. The method of claim 2 wherein the map maps columns of the logical table to the corresponding standard column or custom column. 5. The method of claim 4 wherein the map of a logical column includes an identifier of the custom column that is used by the pivot data. 6. The method of claim 2 wherein when the logical table is updated, updating the standard table and the custom table. 7. The method of claim 2 wherein the physical table comprises multiple standard tables with standard columns and when a logical column of the logical table is updated, updating only that standard table that includes the corresponding standard column. 8. The method of claim 2 wherein when the updating of the logical table includes adding data for a custom column of a logical row, adding a row to the pivot table for the custom column of the physical row corresponding to the logical row. 9. The method of claim 2 wherein when the updating of the logical table includes updating data for a custom column of a logical row, updating a row of the pivot table for the custom column of the physical row corresponding to the logical row. 10. A computer-readable medium containing a data structure for mapping between a logical table and a physical table, the physical table including a standard table and a custom table, the data structure comprising: for each logical column of the logical table, when the logical column corresponds to a standard column of the standard table, mapping the logical column to the corresponding standard column; and when the logical column corresponds to a custom column of the custom table, mapping the logical column to the corresponding custom column, the custom table being represented by a pivot table. 11. The computer-readable medium of claim 10 wherein the pivot table includes for each custom column, a row for each row of the physical table that includes data for that custom column. 12. The computer-readable medium of claim 10 wherein each mapping of a logical column includes a name for the logical column, an indication of whether the corresponding standard column is a key of its standard table, a name for the corresponding physical column, and a indication of either the standard table or the custom table. 13. The computer-readable medium of claim 10 wherein the mapping of the logical column to the corresponding custom column includes a name of the corresponding pivot table, an identifier of a pivot column that contains a name of the custom column, an identifier of a pivot column that contains data of the custom column, and an identifier of a pivot column that contains a key for a physical row. 14. A computer-readable medium containing instructions for controlling a computer system to update data, by a method comprising: providing a map between standard and custom columns of a physical table and logical columns of a logical table, the custom columns being represented using a pivot table; providing an indication of an update to the logical table; using the map to determine the standard column or custom column to which an updated logical column corresponds; and effecting the update of the determined column of the physical table. 15. The computer-readable medium of claim 14 wherein when the determined column is a custom column updating a row of the pivot table. 16. The computer-readable medium of claim 15 wherein each row of the pivot table identifies a custom column, a row of the physical table, and data for that custom column of that row of the physical data. 17. The computer-readable medium of claim 14 wherein the logical table is generated by providing a result set containing physical data retrieved from standard and custom columns of the physical table and the map is used to map the retrieved physical data to the corresponding logical data of the logical table. 18. The computer-readable medium of claim 17 wherein the logical table is represented as a dataset object. 19. The computer-readable medium of claim 18 including adding tracker tables to the dataset object to log updates to the logical table. 20. The computer-readable medium of claim 14 wherein the physical table includes multiple standard tables and the updating includes updating only those standard tables with standard columns corresponding to logical columns that were updated. 21. A computer-readable medium containing instructions for controlling a computer system to update data, by a method comprising: providing a map between physical columns of a physical table and logical columns of a logical table, the physical table being represented a multiple database tables within a database; providing a result set containing physical data derived from the multiple database tables; organizing the physical data of the result set into a logical table based on the provided map; providing an indication of an update to the logical table, the update updating logical columns that correspond to physical columns represented in different database tables; using the provided map to determine to which columns of which database tables the updated logical columns correspond; and effecting the update of the determined columns of the database tables. 22. The computer-readable medium of claim 21 wherein the database tables correspond to standard tables and a custom table, the custom table being represented by a pivot table. 23. The computer-readable medium of claim 22 wherein when a determined column is a custom column of the custom table, updating a row of the pivot table. 24. The computer-readable medium of claim 22 wherein each row of the pivot table identifies a custom column, a row of the physical table, and data for that custom column of that row of the physical data. 25. The computer-readable medium of claim 21 wherein the logical table is represented as a dataset object. 26. The computer-readable medium of claim 25 including adding tracker tables to the dataset object to log updates to the logical table. 27. The computer-readable medium of claim 21 wherein the physical table includes multiple standard tables and the updating includes updating only those standard tables with standard columns corresponding to logical columns that were updated. 28. A method for presenting a view of data, the method comprising: providing a map between physical columns of a physical table and logical columns of a logical table, a physical columns including a standard column and a custom column, the custom column being represented with pivot data; and generating a logical view of the physical data that contains a logical column for standard column and the custom column. 29. The method of claim 28 wherein when the logical view is updated, using the map to propagate the update to the physical table. 30. The method of claim 28 wherein the logical view includes standard columns from multiple standard tables of the physical table. 31. The method of claim 30 wherein when a logical column is updated, updating only the standard table that contains the standard column corresponding to the updated logical column. 32. The method of claim 28 wherein the logical view is represented by a dataset object generated from a result set derived from the physical table.
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TECHNICAL FIELD The described technology relates generally to mapping between logical data and physical data and including to mapping when the physical data includes custom data. BACKGROUND Many applications use a database to store their data. The database for an application is typically designed by the developer of the application to include a table for each entity used by the application. Each entity table contains a row for each specific entity and various columns for storing properties of the entity. For example, in the case of a project management application, the entities may include a project, a task, an assignment, or a resource, and a specific entity is a specific project, a specific task, a specific assignment, or a specific resource. The project table may contain a project identifier column, a project name column, a project start date column, and so on. The project identifier column contains the unique identifier of a specific project and is referred to as a “unique key” of the project table. Each row of the project table corresponds to a specific project, and the cells of a row contain the data of that specific project for the columns. A task table may contain a task identifier column, project identifier column, task name column, and so on. The task identifier column contains the unique identifiers of specific tasks. The project identifier column contains the project identifier of the specific project with which the task is associated and is referred to as a “foreign key.” Each row of the task table corresponds to a specific task. Complex applications may have many hundreds of properties associated with an entity. This presents problems for databases that limit the number of columns of a table. For example, some databases may limit the number of columns to 128 or 256. To overcome this problem, applications may store data for an entity in multiple database tables. For example, if an application needs 300 columns to represent the properties of an entity and the limit on the number of columns of a table is 128, then the developer of the application may divide the 300 columns across three tables with 101 columns in each table. Each table may contain a unique key column and 100 property columns. When the properties of a specific entity is added to the database, the application generates a unique identifier for that specific entity and adds a row to each of the three tables with its unique key set to that unique identifier. The combination of the rows from the three tables with the same unique identifier corresponds to the columns for the entity. To access the data for that specific entity, the application may join the three tables. As a result, at least for viewing purposes, the join results in a logical data view that contains the unique identifier column and the 300 property columns. Even though these complex applications have many properties associated with an entity, referred to as “standard” properties or columns, users may need to have additional properties associated with an entity. For example, in the case of a project management application, a user may need to track project type and project status, which may have no corresponding standard column. To assist users in defining their own properties for an entity, applications may allow custom columns to be defined. For example, a user may define a type custom column and a status custom column to track the type and status of projects. The custom column can be considered just one more column associated with an entity. Although custom columns could be supported by modifying the schema of the database, such modifications can be time-consuming and error-prone, especially if performed by the users of the application. To allow users the flexibility to create custom columns without modifying the schema of the database, some applications use a “pivot” table to store information relating to custom columns. A pivot table for an entity would typically include a key column, a custom column name column, and a data column. Whenever data for a custom column is to be added for a specific entity, a new row is added to the pivot table that contains the unique key associated with that specific entity, the name of the custom column, and the data. The use of pivot tables to represent custom columns may make it difficult for a user to retrieve all the properties associated with a specific entity. In particular, although a join can be used to combine the data of standard tables, the data of the custom columns cannot be joined so easily. Moreover, even if with only standard tables are joined to provide a logical data view, some databases may not allow updates via the logical data view. It would be desirable to provide a logical data view that would integrate both standard columns and custom columns and would allow for the updating of data of both standard columns and custom columns via a logical data view. SUMMARY A method and system for providing a logical view of data that combines standard and custom fields is provided. The system creates a logical view of physical data that includes standard data of standard fields and custom data of custom fields. The system has a map that maps logical fields of logical data to the corresponding standard fields or custom fields of the physical data. The system uses the map to generate the logical view. When the custom fields are represented by pivot data, the system converts the pivot data so that it appears as a logical field. The system may allow the updating of data of a custom field via the logical view and a standard field when the standard fields are represented as standard columns of multiple standard database tables. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram that illustrates a physical table of a database representing an entity and a corresponding logical table in one embodiment. FIG. 2 is a block diagram that illustrates physical tables for a project management application in one embodiment. FIG. 3 is a block diagram that illustrates sample data of a project pivot table and custom column table in one embodiment. FIG. 4 is a block diagram that illustrates a schema for a map of logical data to physical data in one embodiment. FIG. 5 is a block diagram illustrating the interaction of components of the mapping system in one embodiment. FIG. 6 is a flow diagram that illustrates the create dataset object component in one embodiment. FIG. 7 is a flow diagram that illustrates the processing of the check result set component in one embodiment. FIG. 8 is a flow diagram that illustrates the processing of the populate logical table component in one embodiment. FIG. 9 is a flow diagram that illustrates the processing of the transform logical to physical update component in one embodiment. DETAILED DESCRIPTION A method and system for providing a view of data that combines standard and custom data is provided. In one embodiment, a mapping system provides a map between physical fields of physical data and logical fields of logical data. The physical fields may include standard fields and custom fields. The custom fields may be represented using pivot data. To create a view of the physical data, the physical data is queried to generate a result set that includes custom fields represented using pivot data and standard fields. The mapping system uses the map to generate a logical data view that integrates standard and custom fields in a way that hides from a user or client the distinction between standard and custom field. In addition, the mapping system tracks updates to the logical data and then updates the corresponding physical data. The mapping system may keep a log of the updates that are made to the logical data. The mapping system uses the map to identify which standard fields and custom fields need to be updated and updates them accordingly. In this way, the distinction between standard fields and custom fields is hidden from the logical data view and updates made to the logical data view can be reflected in the physical data. In one embodiment, the mapping system maps a physical table of a database to a logical table representing a logical view that integrates standard columns and custom columns. The physical table includes a standard table with standard columns and a custom table with custom columns. The custom table may be implemented as a pivot table. The mapping system provides a map between standard and custom columns and logical columns. The map may include for each logical column of the logical table an indication of the corresponding standard column and standard table or an indication of the corresponding custom column. The pivot table may include a key column, custom column name column, and data column. The set of unique custom column names within the custom column name column of the pivot table represents all the custom columns that have been defined for the physical table. In one embodiment, the name of the pivot table and its column names may be hard-coded into the mapping system. Alternatively, the map may map each logical column that corresponds to a custom column to the name of the corresponding pivot table and the names of the columns within the pivot table corresponding to the key, custom column name, and data columns. The mapping system may represent a logical table as a dataset object that defines a logical view and methods for accessing the logical data. (See, D. Michalk, “The DataSet Object: At Your Web Service,” XML & Web Services Magazine, October/November 2001, which is hereby incorporated by reference.) The mapping system may add functionality to the dataset object to track changes that are made to the data within the dataset object. When the changes made to the logical table are to be committed to the physical table, the mapping system processes each change by mapping the updated columns of the logical table to the corresponding physical columns of the physical table. The updated columns may correspond to standard columns or custom columns. If an updated column corresponds to a custom column, then the mapping system updates the corresponding pivot table as appropriate. In one embodiment, the physical table may include multiple standard tables, for example, if the database limits the number of columns within a table to less than the number needed to represent all the properties of an entity. The mapping system allows for individual standard tables to be updated, rather than updating all the columns across all the standard tables for a row. Prior techniques for updating a view that included a join of multiple tables may have required that all the columns of all the tables be updated even when only a single column of the view is updated. The mapping system may also define a logical table to contain logical columns corresponding to different physical tables. For example, a logical table may contain a row for each task with logical columns corresponding to various physical columns of the task physical table and a physical column for the project physical table. FIG. 1 is a block diagram that illustrates a physical table of a database representing an entity and a corresponding logical table in one embodiment. The physical table 110 includes standard tables 111-112 and a custom table 113. Each standard table includes a unique key standard column and other standard columns that each correspond to a property of the entity represented by the physical table. The custom table is implemented as a pivot table 114. The custom table, however, logically includes a unique key column and each custom column. A row of the physical table for a specific entity, identified by a unique identifier, corresponds to a join of the standard tables and the custom table. The mapping system generates the logical table 120, which may be represented as a dataset object, corresponding to the physical table by creating a logical join of the standard tables and the custom table. The join with the custom table is logical in the sense that the custom table is a logical representation of the pivot table. The mapping system converts the rows of the pivot table to the corresponding column of the custom table to effect the logical join. FIG. 2 is a block diagram that illustrates physical tables for a project management application in one embodiment. The physical tables include a project table 210 corresponding to a project entity and a task table 220 corresponding to a task entity. The project table includes project standard tables 211-212 and project pivot table 213. The task table includes task standard table 221-222 and task pivot table 223. The project standard tables contain a unique project identifier column and various standard columns relating to project properties. The project pivot table contains an entry for each cell of the project table that contains a custom value. The project pivot table includes a key column that contains the project unique identifier, the custom column unique identifier column, and a data column. The custom column unique identifier column is a reference to a row in a custom column table 230. The custom column table contains a row for each custom column that has been defined. Each row contains name, category, and data type of a custom column. The task standard tables contain a task unique identifier column and various standard columns relating to task properties. The task pivot table contains an entry for each cell of the task table in a manner similar to the project pivot table. FIG. 3 is a block diagram that illustrates sample data of a project custom table represented as a project pivot table and custom column table in one embodiment. The custom column table 320 includes rows 321-322. Row 321 defines the custom column “project” with a data type of “text” and an indication that the column is required to have a data value. Row 322 defines the custom column “status” with the data type of “text” and an indication that the column is not required to have a data value. The project pivot table 310 includes rows 311-313. Row 311 corresponds to the cell for the “type” custom column for project 10. This row indicates that project 10 has a type of “A.” Row 312 corresponds to the cell for the “type” custom column for project 20. This row indicates that project 20 has a type of “B.” Row 313 corresponds to the cell for the “status” custom column for project 10. This row indicates that project 10 has a status of “done.” The custom column unique identifier column of the project pivot table contains a foreign key to the custom column table. The custom column table thus contains a row for each custom column describing its characteristics. FIG. 4 is a block diagram that illustrates a schema for a map of logical data to physical data in one embodiment. The schema defines logical table metadata 410, logical column metadata 420, standard table metadata 430, and pivot table metadata 440. The logical table metadata contains a row for each logical table corresponding to a physical table. In one embodiment, a logical table may be generated from multiple physical tables. The logical table metadata contains logical unique identifier, name, and description columns. The logical column metadata contains a row for each logical column. It includes a logical column unique identifier, name, logical table unique identifier (as a foreign key), is key, is calculated, physical column name, standard table unique identifier (as a foreign key), and pivot table unique identifier (as a foreign key) columns. The logical table unique identifier column maps the logical column to the corresponding logical table in which it is contained. The standard table unique identifier column maps the logical column to the corresponding standard table. The pivot table unique identifier maps the logical column to the corresponding row of the pivot table. The physical column name contains the column name associated with either the standard table or the pivot table. The standard table metadata has one row for each standard table and includes a physical table unique identifier and name column. The name identifies the name of the physical table. The pivot table metadata includes a row for each custom column and contains a pivot table unique identifier, name, value column, name column, and key column columns. The table name column specifies the name of the pivot table. The value column identifies the name of the column of the pivot table that contains the data value. The name column identifies the column of the pivot table that contains the name of the custom column. The key column identifies the column of the pivot that contains the key of the corresponding physical table. FIG. 5 is a block diagram illustrating the interaction of components of the mapping system in one embodiment. The figure illustrates a database layer 510, a data access layer 520, a middle tier 530, and a client 540. The database may be connected to the data access layer via a network, and the client may be connected to the middle tier via a network. The database includes a project physical table comprising project standard tables 511-512 and a project custom table 513. When a result set is generated for the project physical table, it is passed to the create dataset component 521 of the data access layer. If a network connects the database and the data access layer, then data sent via the network would typically need to be serialized and de-serialized. The create dataset component uses the logical-to-physical map to create a dataset object 522 that represents the logical table. The dataset object is passed to the add tracker component 531 of the middle tier. The add tracker component adds tracker tables to the dataset object 532 and adds tracker object 533. The tracker object is responsible for tracking each update to the logical table of the dataset objects and storing an indication of the update in the tracker tables. The dataset object is then serialized (when the middle tier and client are connected via a network) and provided to the client. The client de-serializes the dataset object and instantiates dataset object 541 and tracker object 542. The client accesses the dataset object to view and update to the logical tables of the dataset object. The tracker object logs all updates, such as updating a cell, adding a row, or deleting a row. Upon completion, the client serializes the dataset object and provides it to the middle tier. The middle tier de-serializes the dataset object and instantiates a dataset object 536 and tracker object 537. The extract updates component extracts the update information from the tracker tables and provides that information to the transform logical to physical update component 525 of the data access layer. The transform logical to physical update component uses the logical-to-physical map to generate updates to the project physical table corresponding to the updates made by the client to the logical table. The component may generate a series of SQL statements. The computing device on which the mapping system is implemented may include a central processing unit, memory, input devices (e.g., keyboard and pointing devices), output devices (e.g., display devices), and storage devices (e.g., disk drives). The memory and storage devices are computer-readable media that may contain instructions that implement the mapping system. In addition, the data structures and message structures may be stored or transmitted via a data transmission medium, such as a signal on a communications link. Various communications links may be used, such as the Internet, a local area network, a wide area network, or a point-to-point dial-up connection. FIG. 5 illustrates an example of a suitable operating environment in which the mapping system may be implemented. The operating environment is only one example of a suitable operating environment and is not intended to suggest any limitation as to the scope of use or functionality of the mapping system. Other well-known computing systems, environments, and configurations that may be suitable for use include personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. The mapping system may be described in the general context of computer-executable instructions, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically, the functionality of the program modules may be combined or distributed as desired in various embodiments. FIG. 6 is a flow diagram that illustrates the create dataset object component in one embodiment. The component is passed a result set and creates a dataset object representing a logical view of the result set. In this embodiment, the component selects each logical table and logical column of the logical table and adds a column to that logical table if the corresponding physical column is represented in the result set. One skilled in the art will appreciate that selecting each of the physical columns of the result set can alternatively identify the logical columns for the logical tables. In block 601, the component selects the next logical table that is defined in the logical-to-physical map. In decision block 602, if all the logical tables have already been selected, then the component completes, else the component continues at block 603. In block 603, the component selects the next logical column of the selected logical table. In decision block 604, if all the logical columns of the selected logical table have already been selected, then the component continues at block 608, else the component continues at block 605. In block 605, the component invokes the check result set component to determine whether the physical column corresponding to the selected logical column is in the result set. In decision block 606, if the physical column is in the result set, then the component continues at block 607, else the component loops to block 603 to select the next logical column. In block 607, the component adds the selected logical column to logical table and then loops to block 603 to select the next logical column. In block 608, the component invokes the populate logical table component to add rows to the logical table that are generated from the result set and loops to block 601 to select the next logical table. FIG. 7 is a flow diagram that illustrates the processing of the check result set component in one embodiment. This component is passed an indication of a logical column and returns an indication as to whether the corresponding physical column is in the result set. In decision block 701, if the logical column corresponds to a custom column, then the component continues at block 704, else the component continues at block 702. In decision block 702, if the standard table that contains the standard column corresponding to the logical column is in the result set, then the component continues at block 703, else the component returns an indication of not found. In decision block 703, if the standard column corresponding to the logical column is in the result set, then the component returns an indication of found, else the component returns an indication of not found. In decision block 704, if the custom table corresponding to logical column is in the result set, then the component continues at block 705, else the component returns an indication of not found. In decision block 705, if the custom column corresponding to logical column is in the result set, then the component returns an indication of found, else the component returns an indication of not found. FIG. 8 is a flow diagram that illustrates the processing of the populate logical table component in one embodiment. The component is passed an indication of a logical table of the dataset object and adds rows to the logical table corresponding to the data of the result set. In block 801, the component selects the next row of the physical table corresponding to the logical table. In decision block 802, if all the rows of the physical table have already been selected, then the component returns, else the component continues at block 803. In block 803, the component selects the next logical column of the logical table. In decision block 804, if all the logical columns of the logical table have already been selected, then the component loops to block 801 to select the next row of the physical table, else the component continues at block 805. In block 805, the component retrieves the data of the cell from the result set for the selected logical column of the selected row of the physical table. In block 806, the component adds retrieved data to logical column of the logical table and then loops to block 803 to select the next logical column. FIG. 9 is a flow diagram that illustrates the processing of the transform logical to physical update component in one embodiment. The component is passed a delta data structure that defines various updates to the logical table. The delta data structure contains an entry for each update of a logical table. Each entry identifies a logical table that was updated, logical columns of the logical table that were updated, an operation (e.g., update, delete, or add), and the name of a key and its value which specify the specific row of the logical table that was updated. The entry also contains for each logical column indications of whether to generate a new identifier for this column, whether the data was null before the update, and whether the data is null after the update. In block 901, the component selects the next entry specified in the delta data structure. In decision block 902, if all the entries of the delta data structure have already been selected, then the component returns, else the component continues at block 903. In block 903, the component retrieves the row from the dataset object corresponding to the updated row of the logical table of the selected entry. In block 904, the component selects the next logical column specified in the delta data structure for the selected entry. In block 905, if all the logical columns have already been selected, then the component loops to block 901 to select the next entry of the delta data structure, else the component continues at block 906. In decision block 906, if the selected logical column is a custom column, then the component continues at block 907, else the component continues at block 908. In block 907, the component generates update instructions (e.g., SQL statements) for the database to update the pivot table for the custom column corresponding to the selected logical column and then loops to block 904 to select the next logical column. In block 908, the component adds a column to a row update instruction for the standard table that contains the logical column. The component then loops to block 904 to select the next logical column. The Pseudo Code Table contains sample pseudo code for generating the instructions to update the physical table based on the delta data structure. Pseudo Code Table 1. GenerateSqlFromDelta( ) 2. { 3. For each entry in delta 4. Read operation 5. Read all keys into collection accessible by name 6. Read all columns into collection accessible by name 7. 8. For each standard or custom table of the logical table being updated 9 If table is a custom table 10. For each column in the custom table 11. Call GeneratePivotUpdate(operation, keys, update) 12. Next 13. Else 14. For each column in the standard table 15. Add column name and update value to update list 16. Next 17. 18. Call GenerateUpdate(operation, keys, update list) 19. Endif 20. Next 21. Next 22. } 23. 24. GeneratePivotUpdate(operation, keys, update) 25. { 26. Lookup pivot table definition (definition defines key columns + name column) 27. 28. If the operation is an update, generate an insert if the value is currently null, an update if it is going from a value to another value, and generate a delete if it changes from a value to null. 29. 30. Inserts and deletes generate insert and delete statements respectively. 31. } 32. 33 GenerateUpdate(operation, keys, updatelist) 34. { 35. Generate where clause from keys 36. 37. If operation is delete 38. Generate delete statement only using keys. 39. Else 40. If operation is insert 41. Generate insert using keys and update list as values. 42. Else 43. Generate update using update list and use where clause from earlier in function. 44. 45. Endif 46. Endif 47. } One skilled in the art will appreciate that although specific embodiments of the mapping system have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. One skilled in the art will appreciate that a pivot table can be organized in many different ways. For example, multiple entities can share a common pivot table or each entity can have its own pivot table. Also, a pivot table can be represented as a single database table or multiple database tables. A pivot table contains data for the custom columns of a physical table without having a database column for each custom column. Accordingly, the invention is not limited except by the appended claims.
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<SOH> BACKGROUND <EOH>Many applications use a database to store their data. The database for an application is typically designed by the developer of the application to include a table for each entity used by the application. Each entity table contains a row for each specific entity and various columns for storing properties of the entity. For example, in the case of a project management application, the entities may include a project, a task, an assignment, or a resource, and a specific entity is a specific project, a specific task, a specific assignment, or a specific resource. The project table may contain a project identifier column, a project name column, a project start date column, and so on. The project identifier column contains the unique identifier of a specific project and is referred to as a “unique key” of the project table. Each row of the project table corresponds to a specific project, and the cells of a row contain the data of that specific project for the columns. A task table may contain a task identifier column, project identifier column, task name column, and so on. The task identifier column contains the unique identifiers of specific tasks. The project identifier column contains the project identifier of the specific project with which the task is associated and is referred to as a “foreign key.” Each row of the task table corresponds to a specific task. Complex applications may have many hundreds of properties associated with an entity. This presents problems for databases that limit the number of columns of a table. For example, some databases may limit the number of columns to 128 or 256. To overcome this problem, applications may store data for an entity in multiple database tables. For example, if an application needs 300 columns to represent the properties of an entity and the limit on the number of columns of a table is 128, then the developer of the application may divide the 300 columns across three tables with 101 columns in each table. Each table may contain a unique key column and 100 property columns. When the properties of a specific entity is added to the database, the application generates a unique identifier for that specific entity and adds a row to each of the three tables with its unique key set to that unique identifier. The combination of the rows from the three tables with the same unique identifier corresponds to the columns for the entity. To access the data for that specific entity, the application may join the three tables. As a result, at least for viewing purposes, the join results in a logical data view that contains the unique identifier column and the 300 property columns. Even though these complex applications have many properties associated with an entity, referred to as “standard” properties or columns, users may need to have additional properties associated with an entity. For example, in the case of a project management application, a user may need to track project type and project status, which may have no corresponding standard column. To assist users in defining their own properties for an entity, applications may allow custom columns to be defined. For example, a user may define a type custom column and a status custom column to track the type and status of projects. The custom column can be considered just one more column associated with an entity. Although custom columns could be supported by modifying the schema of the database, such modifications can be time-consuming and error-prone, especially if performed by the users of the application. To allow users the flexibility to create custom columns without modifying the schema of the database, some applications use a “pivot” table to store information relating to custom columns. A pivot table for an entity would typically include a key column, a custom column name column, and a data column. Whenever data for a custom column is to be added for a specific entity, a new row is added to the pivot table that contains the unique key associated with that specific entity, the name of the custom column, and the data. The use of pivot tables to represent custom columns may make it difficult for a user to retrieve all the properties associated with a specific entity. In particular, although a join can be used to combine the data of standard tables, the data of the custom columns cannot be joined so easily. Moreover, even if with only standard tables are joined to provide a logical data view, some databases may not allow updates via the logical data view. It would be desirable to provide a logical data view that would integrate both standard columns and custom columns and would allow for the updating of data of both standard columns and custom columns via a logical data view.
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<SOH> SUMMARY <EOH>A method and system for providing a logical view of data that combines standard and custom fields is provided. The system creates a logical view of physical data that includes standard data of standard fields and custom data of custom fields. The system has a map that maps logical fields of logical data to the corresponding standard fields or custom fields of the physical data. The system uses the map to generate the logical view. When the custom fields are represented by pivot data, the system converts the pivot data so that it appears as a logical field. The system may allow the updating of data of a custom field via the logical view and a standard field when the standard fields are represented as standard columns of multiple standard database tables.
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20040630
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20070731
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20060105
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60844.0
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G06F1730
| 1
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VEILLARD, JACQUES
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METHOD AND SYSTEM FOR MAPPING BETWEEN LOGICAL DATA AND PHYSICAL DATA
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UNDISCOUNTED
| 0
|
ACCEPTED
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G06F
| 2,004
|
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10,881,059
|
ACCEPTED
|
Absorbent towel with projections
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A towel (10) includes a base layer (12) and a plurality of raised projections (14) that project away from the base layer (12). The base layer (12) has a first side (16) and a second side (18). In one embodiment, the projections (14) are discontinuously positioned and are each separately secured to one or both of the sides (16, 18) of the base layer (12). In one embodiment, the projections (14) have a higher coefficient of static friction than the base layer (12) relative to a surface (20). The base layer (12) can be formed from an absorbent material and the projections (14) can be formed from a relatively non-absorbent material. In one embodiment, the projections (14) cover less than approximately 50 percent of one of the sides (16, 18) of the base layer (12). Moreover, in one embodiment, the projections (14) can be substantially hemispherical in shape.
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1. A towel comprising: a base layer having (i) a first side and (ii) a second side that is substantially opposite the first side; and a plurality of raised first projections that are each separately secured to the first side, the first projections having a higher coefficient of static friction than the base layer so that the first projections inhibit relative movement between the towel and the surface when the first projections are in contact with the surface. 2. The towel of claim 1 further comprising a plurality of discontinuous raised second projections that are each separately secured to the second side, the second projections having a higher coefficient of static friction than the base layer so that the second projections inhibit relative movement between the towel and the surface when the second projections are in contact with the surface. 3. The towel of claim 1 wherein the base layer is formed from a liquid-absorbing material. 4. The towel of claim 3 wherein the base layer includes a microfiber material. 5. The towel of claim 1 wherein the first projections are formed from a substantially non-absorbent material. 6. The towel of claim 1 wherein at least some of the first projections are formed at least partially from a plastic material. 7. The towel of claim 1 wherein at least some of the first projections are formed at least partially from a latex material. 8. The towel of claim 1 wherein at least some of the first projections are positioned on the first side so that the first projections have a density of at least nine first projections per square inch. 9. The towel of claim 1 wherein the first projections cover less than approximately 50 percent of the first side of the base layer. 10. The towel of claim 1 wherein at least some of the first projections are positioned at approximately one-quarter inch on center. 11. The towel of claim 1 wherein the first projections project within the range of between at least approximately 0.2 millimeters and less than approximately 2.0 millimeters away from the first side of the base layer. 12. The towel of claim 1 wherein at least some of the first projections are substantially hemispherical in shape. 13. The towel of claim 1 wherein at least some of the first projections are substantially symmetrical about a first axis and a second axis that is orthogonal to the first axis. 14. The towel of claim 13 wherein at least some of the first projections are substantially symmetrical relative to a third axis that is orthogonal to the first axis and the second axis. 15. The towel of claim 1 wherein the second side of the base layer includes a substantially disc-shaped region having a color that is different than substantially the remainder of the second side of the base layer. 16. A towel for use on a surface, the towel comprising: a base layer having (i) a first side and (ii) a second side that is opposite the first side; and a plurality of substantially dome-shaped first projections that are each separately secured to the first side, the first projections being formed at least partially from a substantially non-absorbent plastic material, the first projections having a higher coefficient of static friction relative to the surface than the base layer, the first projections covering less than approximately 50 percent of the first side of the base layer. 17. The towel of claim 16 wherein the first projections project within the range of between at least approximately 0.2 millimeters and less than approximately 2.0 millimeters away from the first side of the base layer. 18. The towel of claim 16 wherein at least some of the first projections are substantially symmetrical about a first axis and a second axis that is orthogonal to the first axis. 19. The towel of claim 18 wherein at least some of the first projections are substantially symmetrical relative to a third axis that is orthogonal to the first axis and the second axis. 20 The towel of claim 16 wherein the second side of the base layer includes a substantially disc-shaped region having a color that is different than substantially the remainder of the second side of the base layer. 21. A method for manufacturing a towel, comprising the steps of: providing a plurality of substantially non-absorbent projections; and separately securing the projections to one side of a liquid-absorbing base layer so that the projections have a coefficient of static friction that is greater than a coefficient of static friction of the base layer relative to a surface. 22. The method of claim 21 wherein the step of providing a plurality of projections includes forming the projections so that each projection is substantially symmetrical relative to a first axis and a second axis that is orthogonal to the first axis. 23. The method of claim 22 wherein the step of providing a plurality of projections includes forming the projections so that each projection is substantially symmetrical relative to a third axis that is orthogonal to the first and second axes. 24. The method of claim 21 wherein the step of separately securing includes covering less than approximately 50 percent of the first side of the base layer with the plurality of projections. 25. The method of claim 21 wherein the step of providing a plurality of projections includes forming each of the projections in substantially a dome shape. 26. The method of claim 21 wherein the step of separately securing includes positioning the first projections to project within the range of between at least approximately 0.2 millimeters and less than approximately 2.0 millimeters away from the first side of the base layer. 27. The method of claim 21 further comprising the step of positioning a substantially disc-shaped focal region on a second side of the base layer so that the focal region has a color that is different than substantially the remainder of the second side.
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RELATED APPLICATION This Application claims the benefit on U.S. Provisional Application Ser. No. 60/484,697 filed on Jul. 3, 2003. The contents of U.S. Provisional Application Ser. No. 60/484,697 are incorporated herein by reference. BACKGROUND Strength and coordination exercises are becoming increasingly more popular these days. Within health-conscious cultures, sports such as jogging, swimming and bicycling have long been common forms of exercise. More recently, however, those desiring to stay in shape are seeking different, more innovative ways to achieve or maintain a desired level of physical conditioning and mental health, while at the same time trying to decrease the incidence of injuries due to high impact exercising. For example, various forms of yoga have gained greater acceptance within today's society. Yoga is known to Increase strength and flexibility, while relaxing the mind through focusing on holding certain body positions. Consequently, yoga and other similar disciplines can provide participants with an increased fitness level and improved state of mind. Typically, cushioned rubber mats are used by those who practice yoga for providing a soft surface for kneeling, standing, and lying down. However, due to the physical demand of balancing while holding various poses for extended periods of time, the participants can perspire onto the mats, causing the mats to become slick, thereby increasing the likelihood of a slipping injury. Thus, the participant can become distracted from proper focus during the practice of yoga. Further, the mats are generally relatively non-absorbent, and offer few benefits other than creating a padded area for use by the yoga participants. SUMMARY The present invention is directed to a towel that includes a base layer and a plurality of raised projections that project away from the base layer. The base layer has a first side and a second side. In one embodiment, the projections can be discontinuously positioned and can each be separately secured to one or both of the sides of the base layer. In one embodiment, the projections have a higher coefficient of static friction than the base layer to inhibit relative movement between the towel and a surface upon which the towel is placed when the projections are in contact with the surface. In one embodiment, the base layer is formed from a liquid-absorbing material such as a microfiber fabric material. Further, at least some of the projections are formed at least partially from a relatively non-absorbent latex material. In one embodiment, the projections cover less than approximately 50 percent of one of the sides of the base layer. Moreover, in one particular embodiment, at least some of the projections are substantially hemispherical in shape. The present invention also includes a method for manufacturing a towel. BRIEF DESCRIPTION OF THE DRAWINGS The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which: FIG. 1 is a perspective view of one embodiment of a towel having features of the present invention, shown in a first configuration; FIG. 2 is a partial plan view of a portion of another embodiment of the towel having features of the present invention; FIG. 3A is a perspective view of a first embodiment of a projection; FIG. 3B is a side view of the projection illustrated in FIG. 3A; FIG. 4A is a perspective view of a second embodiment of a projection; FIG. 4B is a side view of the projection illustrated in FIG. 4A; FIG. 5A is a perspective view of a third embodiment of a projection; FIG. 5B is a side view of the projection illustrated in FIG. 5A; FIG. 6A is a perspective view of a fourth embodiment of a projection; FIG. 6B is a side view of the projection illustrated in FIG. 6A; FIG. 7 is a perspective view of another embodiment of a towel having features of the present invention; and FIG. 8 is a perspective view of another embodiment of a towel having features of the present invention, shown in a second configuration. DESCRIPTION FIG. 1 is a perspective view of a towel 10 in a first, unrolled configuration. In this embodiment, the towel 10 includes a base layer 12 and a plurality of raised projections 14 that project away from the base layer 12 as described herein. The base layer 12 illustrated in FIG. 1 has a first side 16 and a second side 18. In this embodiment, the projections 14 are secured to the first side 16. It is recognized, however, that either side 16, 18 can be the first side 16 or the second side 18. For example, the projections 14 can be secured to the second side 18 of the base layer 12. The towel 10 also includes a perimeter edge 19 that can be bound by any generally acceptable manner known to those skilled in the art. FIG. 1 includes an orientation system that illustrates an X-axis, a Y-axis that is orthogonal to the X-axis and a Z-axis that is orthogonal to the X- and Y-axes. It should be noted that these axes can also be referred to as the first, second and third axes, respectively, and that any of the axes can be the first, second or third axis. In the embodiment illustrated in FIG. 1, towel 10 can be placed on top of a surface 20 that may otherwise become slick or slippery when moisture is introduced onto the surface 20. As shown in FIG. 1, the surface 20 can be any suitable type of yoga or other sports mat, such as those including closed or open-cell foam, for use during yoga or other sporting exercises, as explained in greater detail below. Alternatively, the surface 20 can be any type of flooring material, a table or other furniture, the ground, or any other type of supporting surface. The dimensions of the towel 10 can vary. The towel 10 can be sized to be substantially similar to the surface 20 upon which the towel 10 is placed. In one embodiment, the towel 10 can have dimensions of approximately 24 inches by 68 inches, which are the approximate dimensions of a standard sized yoga mat 20. However, the towel 10 can have dimensions larger or smaller than 24 inches by 68 inches. For example, in alternative embodiments, the towel 10 can be sized for use as a washcloth, a hand towel, a beach towel, a bath towel, a bath mat, a dish towel, a gym or sport towel, a drop cloth, a throw rug, or a baby changing mat, as non-exclusive examples. Further, although the towel 10 is particularly suited for use as a non-clothing item, the towel 10 can be used in other applications where absorbency is beneficial. For instance, the towel 10 can be incorporated into and/or manufactured for use as clothing, such as a bathrobe, a shirt, pants, a hat, a scarf, socks, or any other suitable clothing or non-clothing item. With this design, any moisture such as perspiration, precipitation or incidental moisture can be absorbed by the towel 10 as necessary. The base layer 12 can be formed from relatively absorbent materials that can vary depending upon the design requirements of the towel 10. For instance, the base layer 12 can include any suitably absorbent natural fibers or fabrics, such as cotton, silk, wool, hemp, etc., and/or synthetic materials such as acrylics, polyester microfiber, nylon and/or rayon, as non-exclusive examples. Further, the base layer 12 can have a wide range of thicknesses, weights and/or densities depending upon the absorbency and/or specific usage requirements of the towel 10. The base layer 12 can also include different colored materials and/or different colored patterns, images and the like. For example, in the embodiment illustrated in FIG. 1, the second side 18 of the base layer 12 includes a focal region 22 having a color that is different than substantially the remainder of the base layer 12. With this design, an individual performing yoga, martial arts or other sporting activities can focus his or her attention on the focal region 22 to assist with concentration and/or focus during participation in such exercises. The focal region 22 can be formed from the same material used to form the remainder of the base layer 12, or the focal region 22 can be formed from a different material. In the embodiment illustrated in FIG. 1, the focal region 22 is somewhat disc-shaped and is sized small enough to allow the user to focus on the focal region 22 without substantial movement of the user's eyes during exercise. For example, the focal region 22 can be between approximately 1.0 centimeter and 6.0 centimeters in diameter. However, the size of the focal region 22 can be outside this range. In alternative embodiments, the focal region 22 can have any other suitable configuration, i.e. rectangular, triangular, linear, oval or another appropriate geometry. The material(s) used for the projections 14 can be varied. For example, the projections 14 can be formed from a substantially non-absorbent material such as various forms of plastic (e.g., latex), rubber, epoxy, or any other suitable material, as non-exclusive examples. The material used to form the projections 14 can have a relatively high coefficient of static friction. In one embodiment, the material used to form the projections 14 can have a coefficient of static friction that is greater then a coefficient of static friction of the base layer 12. With this design, the relatively high static friction of the projections 14 decrease the likelihood that the towel 10 will slip, slide or otherwise move relative to the surface 20 upon which the towel 10 is positioned. Stated another way, the projections 14 provide greater traction between the towel 10 and the surface 20. The positioning, shape and size of the projections 14 can vary. In one embodiment, the projections 14 are positioned in a pattern. For example, in the embodiment illustrated in FIG. 1, the projections 14 are positioned in a grid-like arrangement on the base layer 12. In this embodiment, the projections 14 are positioned in a plurality of substantially similar rows, each with a relatively consistent spacing between rows and between individual projections 14. Alternatively, the projections 14 can be positioned in a substantially random manner on the base layer 12. Further, in the embodiment illustrated in FIG. 1, each projection 14 is separately secured to the first side 16 of the base layer 12 in an intermittent, unconnected and/or discontinuous manner. In one embodiment, the projections 14 can be secured to the base layer 12 by using a heat treatment method, which can include melting the projections 14 into position on the base layer 12. Examples of alternative methods that can be used to secure the projections 14 to the base layer 12 include chemical bonding, adhesive, or any other suitable means, although these methods are not intended to be limiting in any manner. Because of the spacing between adjacent projections 14, the base layer 12 can more readily absorb moisture from the surface 20 and/or the user, with reduced or no interference by the projections 14. Stated another way, any inhibition of moisture absorption caused by the projections 14 is reduced or eliminated because a substantially portion of the first side of the base layer 12 is still exposed, notwithstanding the quantity of projections 14 secured to the base layer 12. For example, in one embodiment, the projections 14 are sized, shaped and positioned to cover less than approximately 20% of the total area of the base layer 12. In alternative embodiments, the projections 14 are sized, shaped and positioned to cover less than approximately 25%, 30%, 40%, 50%, 75% or 90% of the total area of the base layer 12. In still an alternative embodiment, two or more of the projections 14 can be continuous, e.g. secured together on the base layer 12 to form lines, curves or other patterns on the base layer 12. Moreover, in one embodiment, each of the projections 14 can be symmetrical relative to two or more axes. For example, in the embodiment illustrated in FIG. 1, the projections 14 are symmetrical relative to three axes: the X-axis, the Y-axis and the Z-axis. In another embodiment, the projections 14 are symmetrical relative to two different axes, such as the X-axis and the Y-axis, although the particular axes about which the projections 14 are symmetrical can vary. With these designs, the manufacturing process is facilitated and the tactile stimulus of the user is enhanced, as set forth in greater detail below. The spacing between the projections 14 can vary. In one embodiment, the spacing of the projections 14 can be approximately one-quarter inch on center. However, the spacing between the projections 14 can be greater or less than one-quarter inch on center achieve the desired level of inhibition of movement between the projections 14 (and thus the base layer 12) and the surface 20. Additionally, because the projections 14 can be positioned relatively close to one another while not unduly inhibiting moisture absorption by the base layer 12, there is less chance for the base layer 12 to move, e.g., between the projections 14, relative to the surface 20. Consequently, injuries caused by slippage of the towel 10 relative to the surface 20 are reduced. Further, the distance that each of the projections 14 projects or extends away from the base layer 12 can vary. For instance, in one embodiment, the projections 14 can project at least approximately 0.1 millimeters away from the first side 16 of the base layer 12. In alternative embodiments, the projections 14 can project at least approximately 0.2 millimeters, 0.3 millimeters, 0.5 millimeters, 0.75 millimeters, 1.0 millimeters, 1.5 millimeters, 2.0 millimeters, 3.0 millimeters or 5.0 millimeters away from the first side 16 of the base layer 12. In alternative embodiments, the projections 14 can project within the range of (i) greater than 0.1 millimeters and less than 5.0 millimeters, (ii) greater than 0.2 millimeters and less than 2.0 millimeters, or (iii) greater than 0.5 millimeters and less than 1.0 millimeter away from the first side 16 of the base layer 12. Still alternatively, the projections 14 can project less than or greater than the foregoing distances and ranges away from the first side 16 of the base layer 12. Moreover, depending upon the spacing of the projections 14, the height of the projections 14, and/or the thickness and/or weight of the base layer 12, a user can receive various tactile sensations when in static or dynamic contact with the towel 10, including force on certain pressure points of the user's body or a massage of the musculature of the user, as non-exclusive examples. With the foregoing designs, the user can receive the requisite level of tactile stimulus during usage of the towel 10. FIG. 2 is a partial plan view of an alternative embodiment of the towel 210. In this embodiment, the projections 214 are positioned in a repeated, somewhat diamond-shaped pattern on the base layer 212 so that the rows are somewhat staggered from those illustrated in FIG. 1. Still alternatively, the projections 214 can be separately positioned to form concentric circles, triangles, or any other suitable geometric patterns. FIGS. 3A-6B show various representative shapes of several embodiments of the projections 14. The embodiments depicted in FIGS. 3A-6B are provided for convenience of discussion only, and are not intended to limit the scope of the present invention in any manner. The shape of the projections 14 can vary depending upon the level of tactile stimulus desired by the user in contact with the towel 10, and/or the extent to which a higher level of friction is necessary or desired between the projections 14 and the surface 20. FIG. 3A is a top view of one embodiment of the shape of a projection 314. In this embodiment, the projection 314 has a round or circular footprint. FIG. 3B is a side view of the projection 314 illustrated in FIG. 3A. FIG. 3B shows that the projection 314 can have a substantially dome or hemispherical shape. FIG. 4A is a top view of one embodiment of the shape of a projection 414. In this embodiment, the projection 414 has a rectangular footprint. FIG. 4B is a side view of the projection 414 illustrated in FIG. 4A. FIG. 4B shows that the projections 414 have a substantially frusto-pyramidal shape. FIG. 5A is a top view of one embodiment of the shape of a projection 514. In this embodiment, the projection 514 has a round or circular footprint. FIG. 4B is a side view of the projection 514 illustrated in FIG. 5A. FIG. 5B shows that the projection 514 can have a substantially cylindrical, planar or flat shape. FIG. 6A is a top view of one embodiment of the shape of a projection 614. In this embodiment, the projection 614 has a round or circular footprint. FIG. 6B is a side view of the projection 614 illustrated in FIG. 6A. FIG. 6B shows that the projection 614 can have a substantially frusto-conical shape. FIG. 7 is an alternative embodiment of a towel 710. In this embodiment, the towel 710 includes a plurality of first projections 714A on each of the first side 716 of the base layer 712, and a plurality of second projections 714B the second side 718 of the base layer 712. With this design, the towel 710 can be used with either side 716, 718 facing downward (toward a surface 720) or upward (away from the surface 720). Further, the user can feel an increase in the tactile stimulation depending upon the quantity, shape, size and positioning of the projections 714A, 714B secured to the base layer 712 of the towel 710. The projections 714A, 714B can be substantially the same shape, size and positioning on both sides 716, 718, or the shape, size and positioning can differ from the first side 716 to the second side 718. FIG. 8 illustrates an embodiment of the towel 810 in a second, rolled-up configuration. In this embodiment, the towel 810 can be substantially similar to those previously described. However, the towel 810 can also include a strap 824 that is removably or fixedly attached to the base layer 812. The strap 824 can be attached to the base layer 812 by any suitable means, including loop and pile, hook and loop, snaps, etc. Alternatively, the strap 824 can be tied around the base layer 812 to maintain the towel 810 in the rolled-up configuration. The strap 824 can include a handle 826 for more easily carrying or otherwise transporting the towel 810 between locations. Further, the strap 824 can be used for maintaining the towel 810 in the second, rolled up configuration (as illustrated in FIG. 8), e.g. for storage, until the towel 810 is ready for use. While the particular towel 10 as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of some of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.
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<SOH> BACKGROUND <EOH>Strength and coordination exercises are becoming increasingly more popular these days. Within health-conscious cultures, sports such as jogging, swimming and bicycling have long been common forms of exercise. More recently, however, those desiring to stay in shape are seeking different, more innovative ways to achieve or maintain a desired level of physical conditioning and mental health, while at the same time trying to decrease the incidence of injuries due to high impact exercising. For example, various forms of yoga have gained greater acceptance within today's society. Yoga is known to Increase strength and flexibility, while relaxing the mind through focusing on holding certain body positions. Consequently, yoga and other similar disciplines can provide participants with an increased fitness level and improved state of mind. Typically, cushioned rubber mats are used by those who practice yoga for providing a soft surface for kneeling, standing, and lying down. However, due to the physical demand of balancing while holding various poses for extended periods of time, the participants can perspire onto the mats, causing the mats to become slick, thereby increasing the likelihood of a slipping injury. Thus, the participant can become distracted from proper focus during the practice of yoga. Further, the mats are generally relatively non-absorbent, and offer few benefits other than creating a padded area for use by the yoga participants.
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<SOH> SUMMARY <EOH>The present invention is directed to a towel that includes a base layer and a plurality of raised projections that project away from the base layer. The base layer has a first side and a second side. In one embodiment, the projections can be discontinuously positioned and can each be separately secured to one or both of the sides of the base layer. In one embodiment, the projections have a higher coefficient of static friction than the base layer to inhibit relative movement between the towel and a surface upon which the towel is placed when the projections are in contact with the surface. In one embodiment, the base layer is formed from a liquid-absorbing material such as a microfiber fabric material. Further, at least some of the projections are formed at least partially from a relatively non-absorbent latex material. In one embodiment, the projections cover less than approximately 50 percent of one of the sides of the base layer. Moreover, in one particular embodiment, at least some of the projections are substantially hemispherical in shape. The present invention also includes a method for manufacturing a towel.
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20040629
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20051108
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20050106
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64647.0
| 5
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LAGMAN, FREDERICK LYNDON
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ABSORBENT TOWEL WITH PROJECTIONS
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SMALL
| 0
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ACCEPTED
| 2,004
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10,881,066
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ACCEPTED
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Safety relay system
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A safety relay system includes one or more additional input units each for sending safety input from a safety component, a master unit for receiving the safety input from the additional input unit and providing safety output to operate a safety relay based on the safety input, a safety information line for transferring safety information between the units, a non-safety information line for transferring non-safety information separate from the safety input, the non-safety information being information concerning an operation state of each safety component or each unit, and a non-safety information output section for outputting the non-safety information transferred on the non-safety information line.
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1. A safety relay system for acquiring safety input from one or more safety components, checking a safety state, if safety is checked, outputting safety output for opening/closing a safety relay to enable an external connected machine connected to the safety relay to operate and on the other hand, if it is determined that the state is unsafe, opening/closing the safety relay to directly or indirectly stop the operation of at least a hazardous part in the external connected machine, said safety relay system comprising: one or more additional input units each for sending safety input from the safety component; a master unit for receiving the safety input from said additional input unit and providing safety output to operate the safety relay based on the safety input; a safety information line for transferring safety information between said units; a non-safety information line for transferring non-safety information separate from the safety input, the non-safety information being information concerning the operation state of each safety component or each unit; and a non-safety information output section for outputting the non-safety information transferred on said non-safety information line. 2. The safety relay system as claimed in claim 1 wherein each additional input unit comprises a non-safety control section for communicating the non-safety information, and the non-safety information is transferred to each adjacent unit in order, whereby each additional input unit communicates with said master unit. 3. The safety relay system as claimed in claim 1 wherein each additional input unit comprises a non-safety control section for communicating the non-safety information, and each additional input unit communicates directly with said master unit. 4. The safety relay system as claimed in claim 1 further comprising: an end unit being connected to one end of said one or more additional input units for causing said master unit to detect the number of the connected additional input units. 5. The safety relay system as claimed in claim 1 further comprising: one or more additional output units for receiving the safety output from said master unit and operating the safety relay based on the received safety output. 6. The safety relay system as claimed in claim 5 wherein said one or more additional input units and the one or more additional output units are connected to said safety information line for enabling said additional input units to communicate safety input to each other and the additional output units to communicate safety output to each other. 7. The safety relay system as claimed in claim 5 wherein said safety information line connects the one or more additional input units and the one or more additional output units as the same line for enabling the safety input and the safety output to be communicated between each unit and said master unit. 8. The safety relay system as claimed in claim 5 wherein said safety information line is connected via a connector provided on each unit and either of the additional input unit and the additional output unit can be connected to the same connector. 9. The safety relay system as claimed in claim 8 wherein said safety information line comprises a safety input line and a safety output line and the safety input line is connected to said additional input unit for sending safety input and the safety output line is connected to said additional output unit for sending safety output. 10. The safety relay system as claimed in claim 1 wherein said safety information line is a serial line. 11. The safety relay system as claimed in claim 1 wherein each additional input unit comprises a safety control section for performing AND operation for safety input transmitted via said safety information line from the additional input unit connected to the preceding stage of that additional input unit and safety input from the safety component connected to that additional input unit and outputting the AND operation result as safety input. 12. The safety relay system as claimed in claim 4 wherein said safety information line is parallel lines and wherein when safety input is transmitted straightly from said master unit through said additional input units to the end unit and then is transmitted from the end unit to said master unit, each time the safety input passes through each of said additional input units, a shift is made on the parallel line to transmit the safety input, and the number of said connected additional input units can be detected based on which parallel line the safety input received at said master unit is detected from. 13. The safety relay system as claimed in claim 1 further comprising: a power unit being connected to said master unit for supplying power to said safety relay system. 14. The safety relay system as claimed in claim 4 wherein a rating declaration part is provided on a side of the end unit. 15. The safety relay system as claimed in claim 5 wherein at least either said additional input unit or the additional output unit comprises a non-safety information display section for externally displaying non-safety information and a non-safety information interface for sending non-safety information to an external machine. 16. The safety relay system as claimed in claim 1 wherein the non-safety information includes at least any of ON/OFF information of the safety component connected to the master unit or each additional input unit, an error state and error information of each unit, output information of said master unit or the additional output unit, operation mode information of each additional input unit, or setup information of each unit.
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BACKGROUND OF THE INVENTION 1. Field of the Invention Th present invention relates to a high-reliability safety relay system suited for use, for example, to drive a target load only if a plurality of input conditions concerning safety check, etc., all hold. 2. Description of the Related Art A safety measure apparatus is used from the necessity for a safety measure in various quarters. For example, a machine tool, a pressing machine, a robot, a packing machine, an elevator, and the like are used at a manufacturing location, and various safety measures become necessary to protect workers from the machines, the apparatus, etc. For example, when an anomaly occurs, power supply to the machine is cut off, thereby stopping the mechanical operation for securing safety for workers. To construct such a system, a safety relay apparatus is used. The safety relay apparatus opens and closes electrical contacts to control energization. Some safety relay apparatus, for example, contain a plurality of relays each with a forcible guide and also include a self-holding function, duplexing of relay contacts, a back check function based on relay NC contacts, a heterostructure, and the like. The relay with a forcible guide is a relay of the type wherein when one normally open contact (NO) is welded, a different normally closed (NC) contact becomes open in a coil non-excitation state and when one normally closed contact is welded, a different normally open contact becomes open in a coil excitation state (for example, JP-A-11-162317). The self-holding function is a function intended so as not to restart the system if safety information is entered by operating an emergency stop switch, etc., for example, and then the state is restored (reset). Further, the duplexing of relay contacts is also called redundancy; as contacts are provided in parallel, if one contact is welded, it is made possible to provide function by another contact provided in parallel. Further, the back check function based on relay NC contacts is a function for detecting a failure of contact welding, etc., of a relay or a contactor and checking the contact state. The heterostructure (diversity structure) is a structure wherein as different types of members are used in combination, even if trouble of a bug, etc., occurs in a specific member, if the trouble is proper to the type, the same trouble does not occur at the same time and therefore it is made possible to provide function by another member. In recent years, the number of countries and regions in which the safety measure standard is made a legal requirement has increased and particularly a safety relay apparatus or system of the specifications compliant with such a safety measure standard has grown in demand. As the safety standards, ISO, IEC, EN, JIS, and the like are defined in response to the standard targets and regions. Particularly, demands for machine safety are enhanced receiving “guidelines for comprehensive safety standard of machines” notified by the Ministry of Health, Labour and Welfare in June 2001, ISO12100, and execution schedule of putting ISO12100 into JIS. For example, to receive certification of category 4, the highest safety level based on EN954-1 of a standard concerning machine safety of the European standards, a redundant structure, a heterostructure, always making self-inspection of data for maintenance of circuitry or parts, and the like are required. FIG. 9 shows a configuration example of a system for stopping a machine with one safety component to secure safety. The safety component is an element for sending a command for cutting off power supply to any desired machine upon reception of specific operation to secure safety of workers. For example, it corresponds to output of an emergency stop button for the worker to stop the operation of a drive motor for a tooling change, teaching, or adjustment of a machine, output of a safety door switch for detecting a safety door being released to allow the worker to enter the work area of a machine, output of a light curtain for optically detecting the worker approaching a dangerous area, or the like. A safety component 1 is used with a safety output unit 2 for implementing a safety relay apparatus in combination to make up a safety circuit. A safety component switch 3 of normally closed break type is connected to the safety circuit shown in FIG. 9. When the safety circuit is closed, the safety output unit 2 determines that the state is normal, and closes a relay 4 for maintaining power supply to the connected machine. On the other hand, if the safety circuit is opened as the safety component switch 3 is operated manually by the worker or the user or is operated according to output of a sensor, etc., the safety output unit 2 determines that the state is unsafe, and releases the relay 4 for cutting off power supply to the connected machine to stop the operation thereof. To provide the system with redundancy, a dual-redundant safety circuit made up of two safety circuits is formed as shown in FIG. 9 and as the safety component switch 3 is operated, both safety circuits are opened. Accordingly, if one of the safety circuits becomes defective or fails due to contact welding, etc., the other safety circuit functions, so that the machine can be stopped. Further, self-inspection is made, whereby an anomaly of contact welding, etc., can be detected and accumulating of failures can be prevented. The system also adopts a heterostructure for preventing the same defectiveness from occurring at the same time. To make the apparatus or system compliant with the various standards including EN954-1, etc., described above, it is necessary to duplex the circuitry for handling safety information and provide a self-check function and generally the circuit design becomes complicated. On the other hand, even if the system is configured so as to be able to check the safety state by duplexing the circuitry, etc., if the cause, location, etc., of an accident when the system becomes down cannot be detected or determined without any measure. Since the cause of the accident needs to be removed to recover the system, it is desirable that the cause and the location of the accident should be able to be detected to recover the system early. Thus, a circuit for outputting or displaying various pieces of information for facilitating safety check and danger detection may be added to an input unit to which a safety component is connected or a safety output unit to which a safety relay is connected. For example, detailed information concerning safety information, such as the state of the safety component and error information, can be added for easily determining trouble, etc. However, if such detailed information concerning safety information is used as safety input, the circuit for handling the information also requires facilities of duplexing, self-check, etc., for safety, and the circuitry becomes furthermore complicated; this is a problem. If design change occurs in the system, construction of the safety system responsive to the design change needs to be again designed, and the job is extremely intricate. Construction of the system compliant with the condition to receive standard certification is urgently required particularly under the present circumstances in which extreme importance tends to be placed on reception of certification of various safety standards combined with making the safety standard a legal requirement and the demands for the safety measures in recent years. SUMMARY OF THE INVENTION It is an object of the invention to provide a safety relay system for making it possible to add non-safety information relevant to safety information without affecting the safety information for easily maintaining, recovering, redesigning, etc., the safety system. To the end, according to a first aspect of the invention, there is provided a safety relay system for acquiring safety input from one or more safety components, checking a safety state, if safety is checked, outputting safety output for opening/closing a safety relay to enable an external connected machine connected to the safety relay to operate and on the other hand, if it is determined that the state is unsafe, opening/closing the safety relay to directly or indirectly stop the operation of at least a hazardous part in the external connected machine, the safety relay system including one or more additional input units for sending safety input from the safety component; a master unit for receiving the safety input from the additional input unit and providing safety output to operate the safety relay based on the safety input; a safety information line for transferring safety information between the units; a non-safety information line for transferring non-safety information separate from the safety input, the non-safety information being information concerning the operation state of each safety component or each unit; and a non-safety information output section for outputting the non-safety information transferred on the non-safety information line. The safety information transmitted on the safety information line is not affected by the non-safety information transmitted on the non-safety information line and safety output of the master unit operates based on the safety information transmitted on the safety information line and does not depend on the non-safety information on the non-safety information line. Accordingly, the state of each safety component, error information, and the like can be transmitted to the master unit according to the non-safety information, and it is made possible to rapidly recover the system from trouble based on the information. As the non-safety information is separated from the safety information and is sent on the separate line, the circuit of the non-safety information can be simplified. The non-safety information has no effect on the safety information, so that the advanced safety standard can be met without affecting the reliability of the circuit concerning the safety information. The safety relay system according to a second aspect of the invention is characterized by the fact that in the safety relay system of the first aspect, each additional input unit includes a non-safety control section for communicating the non-safety information, and the non-safety information is transferred to each adjacent unit in order, whereby each additional input unit communicates with the master unit. The safety relay system according to a third aspect of the invention is characterized by the fact that in the safety relay system of the first aspect, each additional input unit includes a non-safety control section for communicating the non-safety information, and each additional input unit communicates directly with the master unit. The safety relay system according to a fourth aspect of the invention is characterized by the fact that the safety relay system in any of the first to third aspects further includes an end unit being connected to one end of the one or more additional input units for causing the master unit to detect the number of the connected additional input units. The safety relay system according to a fifth aspect of the invention is characterized by the fact that the safety relay system in any of the first to fourth aspects further includes the one or more additional output units for receiving safety output from the master unit and operating the safety relay based on the received safety output. The safety relay system according to a sixth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to fifth aspects, the one or more-additional input units and the one or more additional output units are connected to the safety information line for enabling the additional input units to communicate safety input to each other and the additional output units to communicate safety output to each other. The safety relay system according to a seventh aspect of the invention is characterized by the fact that in the safety relay system in the fifth or sixth aspect, the safety information line connects the one or more additional input units and the one or more additional output units as the same line for enabling the safety input and the safety output to be communicated between each unit and the master unit. The safety relay system according to an eighth aspect of the invention is characterized by the fact that in the safety relay system in the fifth or sixth aspect, the safety information line is connected via a connector provided on each unit and either of the additional input unit and the additional output unit can be connected to the same connector. The safety relay system according to a ninth aspect of the invention is characterized by the fact that in the safety relay system in the eighth aspect, the safety information line includes a safety input line and a safety output line and the safety input line is connected to the additional input unit for sending safety input and the safety output line is connected to the additional output unit for sending safety output. The safety relay system according to a tenth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to ninth aspects, the safety information line is a serial line. The safety relay system according to an eleventh aspect of the invention is characterized by the fact that in the safety relay system in any of the first to tenth aspects, each additional input unit includes a safety control section for performing AND operation for safety input transmitted via the safety information line from the additional input unit connected to the preceding stage of that additional input unit and safety input from the safety component connected to that additional input unit and outputting the AND operation result as safety input. The safety relay system according to a twelfth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to ninth aspects, the safety information line is parallel lines and when safety input is transmitted straightly from the master unit through the additional input units to the end unit and then is transmitted from the end unit to the master unit, each time the safety input passes through each of the additional input units, a shift is made on the parallel line to transmit the safety input, and the number of the connected additional input units can be detected based on which parallel line the safety input received at the master unit is detected from. The safety relay system according to a thirteenth aspect of the invention is characterized by the fact that the safety relay system in any of the first to twelfth aspects further includes a power unit being connected to the master unit for supplying power to the safety relay system. The safety relay system according to a fourteenth aspect of the invention is characterized by the fact that in the safety relay system in any of the fourth to thirteenth aspects, a rating declaration part is provided on a side of the end unit. The safety relay system according to a fifteenth aspect of the invention is characterized by the fact that in the safety relay system in any of the fifth to fourteenth aspects, at least either the additional input unit or the additional output unit includes a non-safety information display section for externally displaying non-safety information and a non-safety information interface for sending non-safety information to an external machine. The safety relay system according to a sixteenth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to fifteenth aspects, the non-safety information includes at least any of ON/OFF information of the safety component connected to the master unit or each additional input unit, an error state and error information of each unit, output information of the master unit or the additional output unit, operation mode information of each additional input unit, or setup information of each unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram to show a configuration example of a safety relay system; FIG. 2 is a schematic diagram to show a state in which a safety component is added to the safety relay system in FIG. 1; FIG. 3 is a schematic perspective view to show how a master unit is connected to an additional input unit; FIG. 4 is a schematic perspective view to show another example of connection of additional input units to a master unit; FIG. 5 is a block diagram to show the connection state of a safety relay system according to one embodiment of the invention; FIG. 6 is a block diagram to show the connection state of a safety relay system according to another embodiment of the invention; FIG. 7 is a block diagram to show flows of safety information and non-safety information in the safety relay system in FIG. 6; FIG. 8 is a block diagram to show an example wherein each safety control section is implemented as an AND circuit in the safety relay system in FIG. 7; and FIG. 9 is a schematic diagram to show an example of a safety relay system for opening and closing a relay with one safety component. DETAILED DESCRIPTION OF THE INVENTION Referring now to the accompanying drawings, there are shown preferred embodiments of the invention. However, the embodiment shown below is for illustrative purposes only for a safety relay system to embody the technical philosophy of the invention and the invention does not limit the safety relay system to the following. The specification does not limit members as claimed in claims to the members of the embodiment. Particularly, the dimensions, material, shapes, relative placement, etc., of the components described in the embodiment do not define the scope of the invention unless otherwise specified, and are only simple examples for the purpose of description. The sizes of the members, the positional relationship, etc., shown on the accompanying drawings may be exaggerated for purposes of illustration. In the description to follow, the same names or the same reference numerals denote the same or identical members and detailed description is omitted as required. Further, each of the elements making up the invention may be a mode in which a plurality of elements are implemented as a single member for functioning as the plurality of elements or a mode in which a plurality of members share the function of a single member. In the specification, the expression of “input side,” “output side,” etc., is used for the purpose of description, and does not necessarily mean serving only the input, output function. For example, an input side terminal can also handle output or an output side terminal can also handle input. Particularly, if a communication function is not provided between units and a recognition signal is transferred only with a wiring pattern, each connection terminal serves the function of input or output in response to the connection mode. FIG. 1 shows a configuration example of a safety relay system according to one embodiment of the invention. It shows the safety-relevant portions of a control system. In the example, as two safety components 1, safety component switches 3 of emergency stop switches are connected to the safety relay system. Each of the emergency stop switches includes a direct opening operation function (forcible opening function) and has contacts duplexed for forming a safety circuit in each. The safety relay system determines whether or not the state is safe based on the input state from each safety component to check safety. If safety cannot be checked, the safety relay system determines that the state is unsafe, and stops the operation of hazardous parts in the connected machines. The operation not only can be stopped by directly controlling and opening the relays for cutting off power supply, but also can be stopped indirectly through a contactor, etc. Alternatively, a stop instruction may be sent to the connected machine for stopping the operation while actively controlling the hazardous part in the machine based on the instruction in addition to cutting off the power supply. In the example given below, cutting off the power supply by the relays will be discussed, but the invention is not limited to the configuration and means for stopping the connected machine by another method can also be adopted. The expression “unsafe state” throughout the specification is used to mean a state in which the safety component operates normally and a human being attempting to enter a dangerous area is detected or the like; on the other hand, “anomaly” is used to means a state in which the safety component, safety relay apparatus, etc., fails or the like. The safety relay system includes a master unit 5 including relays 4 as the safety relay apparatus and an additional input unit 6 with no relay. [Master Unit] The master unit 5 includes an input section to connect the safety component 1. Further, the master unit 5 contains the relays 4; when a state in which safety cannot be checked, such as anomaly occurrence, is detected, the relay 4 is switched according to a stop instruction to the connected machine. As the relay 4, an electromagnetic relay, a solid-state relay, an electromagnetic relay with a forcible guide mechanism, and the like can be used as required. The relay contacts are duplexed and if one relay contact is welded, the other relay contact is opened, so that the connected machine can be stopped reliably. The relay 4 controls energization of the connected machine such as a motor via a contactor or can also be connected directly to the connected machine not via a contactor. The contactor can also be duplexed so that if one contactor contact is welded, the other contractor contact is opened for stopping the connected machine. In this case, the other contractor contact can be opened even with one contactor contact welded, so that if a start switch is turned on after the connected machine stops, the machine cannot be restarted and a back check function can be provided. The master unit 5 may have no input section to connect the safety component and the safety component may be connected to the additional input unit 6. The master unit 5 may be configured so as to control an external relay without containing the relays 4. [Additional Input Unit 6] The additional input unit 6 also includes an input section to connect the safety component. Unlike the master unit 5, the additional input unit 6 does not contain any relay, so that the circuitry can be simply configured for making the unit inexpensive. The relay includes mechanical operation parts, needs a control circuit for drive, etc., and also requires contacts that can resist energization of a large current and durability of functioning if opening/closing operation is repeated; generally the relay becomes complicated and expensive. Thus, the cost also increases in response to the number of inputs in a configuration in which the relay 4 is provided for each unit to which the safety component 1 is connected. In contrast, in the configuration in FIG. 1 according to the embodiment of the invention, as it is made possible to add the additional input unit 6 having no relay, each unit added in response to the number of inputs can be simplified for reducing the cost. In the additional input unit 6 including no relay, a large current for energizing the relay does not flow and thus wiring connection for a large current is not required and a more inexpensive and easy-to-connect signal line needs only to be connected. Moreover, connector type can be adopted and thus joining can also be performed simply and easily. Further, wiring also lessens, thus contributing to space saving. The safety component switch 3 of the safety component 1 connected to each unit is a normally closed (NC) contact. Each safety circuit is closed and is energized in the normal time, and the unit monitors the state as safety information and closes the relay 4 for energizing the connected machine such as the motor. On the other hand, if the emergency stop switch is pressed during an emergency, the normally closed contacts of the two corresponding safety component switches 3 are broken and the safety switch is opened, so that the unit detects that safety information is lost, and opens the relay 4 to cut off energizing the connected machine. In this state, the connected machine cannot be operated. In the safety relay system, if any of the safety component switches 3 of the safety components 1 connected to the master unit 5 or the additional input unit 6 is operated, the corresponding safety circuit is opened, so that a state in which safety cannot be checked can be detected. Moreover, the safety circuits are independent of each other and thus if defectiveness or a failure occurs in any safety component switch 3, the state can be detected. In the self-inspection of the safety component switch 3 by the master unit 5, for example, a test signal is sent every predetermined period for checking the switch for opening and closing. According to the configuration, duplexing of the relay contacts, the back check function of the contactor contacts, and the self-inspection of the safety component switch are realized and it is made possible to implement a safety relay system that can be compliant with the safety standards including category 4 based on EN954-1. Category 4 requires that “the safety function should not be lost due to a single failure and a single failure should be detected at the next request time of the safety system or before the next request time. If it is impossible, the safety function should not be lost due to accumulating of failures” as design of the safety system for a single failure. The safety components are not limited to the emergency stop switches, and members for checking specific operation to secure safety of workers, such as various sensors. For example, a limit switch for detecting opening and closing of a safety door provided for allowing the worker to enter and exit the work area of the machine on a fence for partitioning the work area of the machine, a light curtain for optically detecting the worker approaching the machine, an area sensor, and the like can be used. If safety is checked by the safety components, safety input is output to the master unit 5 and if safety is checked by all safety components, namely, all safety inputs are set to ON, the master unit 5 sets safety output to ON for permitting the operation of the machine. [Addition of Additional Input Unit 6] FIG. 1 shows an example of connecting the two safety components. To further add a safety component for inputting three safety components, an additional input unit 6B is added to an additional input unit 6A as shown in FIG. 2. As the additional input unit 6B, a similar unit to the additional input unit 6A described above can be used. A safety component switch 3 of a safety component 1 connected to the additional input unit 6B is operated in a similar manner to that described above, and the relay 4 of the master unit 5 is operated according to the operation of the emergency stop switch, etc. Accordingly, another additional input unit 6 can be added for easily installing an additional safety component without again designing the system from the beginning or changing assembling of the circuits. Outputs of the additional input units 6 can be collected in the master unit 5, so that the wiring between the units can be simplified, also contributing to wiring reduction in this point. [Connector] To connect the units, a connector is used. The connector electrically connects a plurality of connection terminals. The additional input unit 6 is provided with an input terminal group and an output terminal group; the input terminal group is connected to another additional input unit 6 or an input end unit 12 and the output terminal group is connected to another additional input unit 6 or the master unit 5. FIG. 3 shows how the additional input unit 6 is connected to the master unit 5 by way of example. In FIG. 3, connectors 7 are inserted into each other and the units are joined as secured by hooks. Since the additional input unit 6 does not include any relay as described above, wiring for a large current flowing through the relay becomes unnecessary and simple connector-type connection is adequate. A connection connector 7 is provided roughly at the center of a side of each unit; the connectors are placed at the corresponding positions so that one becomes male connector 7A and the other becomes female connector 7B on the opposed joint faces. On the joint faces of the units, a pair of hooks 8 on both sides each in the vicinity of an end part of one face and a pair of securing grooves 9 for securing the hooks at the positions on the opposed face corresponding to the hooks are provided. The master unit 5 is provided with the connector 7 and the hooks 8 or the securing grooves 9 only on one face to which the additional input unit 6 is joined; the additional input unit 6 is provided with the connector 7 and the hooks 8, etc., on both faces so as to allow another unit to be connected to either face. Although FIG. 3 shows a connection example of the master unit 5 and the additional input unit 6, the additional input units 6 can be connected or the additional input unit 6 and the input end unit 12 can be connected in a similar manner. The connector is a connector of the type wherein an input terminal group and an output terminal group are provided separately and are joined directly to the output terminal group and the input terminal group of another connector between the units; the connector can also be a connector having an input terminal group and an output terminal group in one piece. For example, in FIG. 4, units are mounted on a connection board 10. In the example in FIG. 4, each unit is provided on one face with a male connector having an input terminal group and an output terminal group in one piece, and the connection board 10 is provided with a plurality of female connectors 7C that can be engaged with the male connectors. The female connectors 7C are provided on the connection board 10 with a given spacing, and the spacing of the female connectors 7C is set so that the units are arranged roughly in a line with the units mounted on the connection board 10. The male and female relationship of the male and female connectors between the units and the connection board may be made opposite, and as the shape of each connector, the type wherein a plurality of pins are placed, the type wherein contacts are placed on a face like a bellows, or the like can be used as required. The position of each connector is not limited to the rough center and can be set to any desired position such as an eccentric position or an end part. The connector itself may be provided with a securing member such as a hook to serve as both electric connection and mechanical joining. Alternatively, the units can also be connected via a connector, a cord, etc., of a different member in addition to the manner in which the connectors provided on the units are joined directly to each other. [Addition of Output Side] The configuration for adding the input side of the safety relay system has been described. Next, the configuration for adding an output side of the safety relay system will be discussed. In the safety relay system, the user may want to add an output side. To increase the number of machines to be stopped when an unsafe state or an anomaly is detected, a relay, etc., to cut off power supply to the machine needs to be added to the output side of the master unit. Then, an additional output unit 16 is joined to the master unit. The safety component is connected to the additional input unit 6 and safety input is obtained from the safety component, as described above. On the other hand, a safety relay output section 58 is connected to the additional output unit 16 and a relay is opened or closed based on a stop signal as safety output. [Status Safety Check Information] Further, each additional output unit 16 continues to detect information to check safety and sends the safety check information to the master unit and the master unit always monitors the safety check information provided by each additional output unit 16, so that the safety relay can be operated continuously to the safety side. That is, control is performed so as to operate the connected machine in a state in which safety can be checked, and stop the operation when safety cannot be checked. Preferably, the safety check information is a dynamic signal. The additional output unit 16 sends status safety check information to the master unit as the safety check information. The status safety check information is a signal to check that the operation of the additional output unit 16 is normal or an anomaly or a failure does not occur by a self-diagnosis circuit contained in the additional out put unit 16, and can also contain error information, etc., of the additional output unit 16. The check is performed regardless of whether the stop signal is ON or OFF. The additional output unit 16 includes a safety check information output section (not shown) for outputting various pieces of safety check information containing the status safety check information. [Safety Information Line 42] FIG. 5 is a block diagram to show the connection state of a safety relay system according to one embodiment of the invention. The safety relay system shown in the figure includes a master unit 5 with one side to which a power unit 30 is connected, a plurality of additional input units 6 and a plurality of additional output units 16 connected to an opposite side of the master unit 5, and an end unit 12 connected to the end face. In the example in the figure, the power unit 30 is connected to the master unit 5, the two additional input units 6 and the two additional output units 16 are connected alternately, and the end unit 12 is connected to the end face. The units are connected in series so that they are contiguous to each other via connectors. A safety information line 42 for transferring safety input is made up of a safety input line 43 and a safety output line 44. A safety control section 45 of each additional input unit 6 is connected to the safety input line 43 and a safety control section 46 of each additional output unit 16 is connected to the safety output line 44. [Safety Input Line 43] The safety input line 43 is a line for transmitting safety input of an input safety circuit signal and is duplexed so as to provide two channels of signals to enhance safety. The safety input signal is an input safety control section signal. The safety input line 43 includes a through line connected through straightly via each unit from the master unit 5 to the end unit 12 and a return line returned from the end unit 12. In the figure, the safety input line 43 is connected to a master unit safety control section 47A of the master unit 5 in series, and the return line of the safety input line 43 connects the safety control sections 46 of the additional input units 6 and on the other hand, is through the additional output units 16. Accordingly, the additional input unit 6 recognizes a signal from another additional input unit 6 or the end unit 12 connected by the safety input line 43 and operates. That is, the additional input unit 6 generates new safety input based on safety input transferred from the preceding stage or the signal from the end unit 12 and safety input indicating the safety state of the safety component connected to the additional input unit 6, and transfers the safety input to the following stage. For example, when safety is checked in the safety components connected to all additional input units 6 as the result of AND operation of the safety input at the preceding stage and the safety input of the additional input unit 6 together is used as new safety input, safety input is obtained in the master unit 5 and safety output can be set to ON based on the safety input. As the safety information is checked in order for each unit, the number of buses can be decreased and the safety control sections 45 and 46 can be simplified. The number of units that can be connected is not limited by the number of buses, and it is made possible to add a large number of units. It is understood that information as to whether a person approaching a dangerous area is detected or the safety component or unit is abnormal when which safety component or unit is determined to be in an unsafe state is information which becomes necessary after the connected machine is stopped and does not directly relate to determination as to whether operation of the connected machine is to be permitted or stopped and therefore need not be handled on the safety information line. The information truly required as the safety information is information indicating that safety of all units or safety components can be checked, namely, information indicating that safety cannot be checked in any of the safety components or units to determine whether operation of the connected machine is to be permitted or stopped. However, the safety input line can also be made parallel lines so as to make shift connection between the units although not shown. For example, the units of the master unit to the end unit are connected straightly and on the other hand, the return line is shifted one at a time whenever one additional input unit is passed through, so that a signal is returned to the master unit with as many shifts as the number of the connected additional input units. Thus, the master unit can check the terminal number at which safety input is detected, thereby detecting the number of the connected additional input units. Output of the safety component connected to each additional input unit is transferred to the master unit while it is shifted in a similar manner, so that safety cannot be checked in which safety component can also be detected. [Safety Output Line 44] The safety output line 44 is a line for transmitting safety output of an output safety circuit signal and is duplexed so as to provide two channels of signals like the safety input line 43. The safety output signal is an output safety control section signal. The safety output line 44 also includes a through line connected through straightly from the master unit 5 to the end unit 12 and a return line returned from the end unit 12, which are connected as a serial line. In the figure, the safety output line 44 is connected to a master unit safety control section 47B of the master unit 5 in series, and the return line of the safety output line 44 connects the safety control sections 46 of the additional output units 16 and on the other hand, is through the additional input units 6. Accordingly, the additional output unit 16 recognizes safety check information from another additional output unit 16 or the end unit 12 connected by the safety output line 44 and operates. That is, the additional output unit 16 generates new safety output based on safety output transferred from the preceding stage or the signal from the end unit 12 and safety check information of the additional output unit 16, and outputs the safety output to the safety control section 46 of the additional output unit 16 at the following stage. Accordingly, the additional output unit 16 checks that the additional output unit 16 at the preceding stage operates normally, and informs the additional output unit 16 at the following stage or the master unit 5 that the additional output unit 16 operates normally. The safety information line 42, namely, the safety input line and the safety output line are indicated by solid line arrows in FIG. 5. Further, the circuit shown in FIG. 5 includes an FSD output line 48 indicated by the alternate long and short dashed line and a synchronizing signal line 49 indicated by the chain double-dashed line in addition to the safety information line 42 as the lines concerning safety signals. An FSD (Final Switch Device) 50 is placed between output from a safety sensor such as a light curtain (OSSD (Output Signal Switching Device)) and MPCE (Machine Primary Control Equipment) for directly stopping external connected machine. The master unit 5 outputs a stop signal from each additional output unit 16 to the MPCE via the FSD output line 48 in response to the output state of the OSSD based on the safety input collected through the additional input units 6, etc. The additional output unit 16 controls the FSD output based on the stop signal. The additional input units 6 can also be monitored through the FSD output line 48. The FSD output line 48 is also provided as two channels for safety. A synchronizing signal section 51 sends a synchronizing signal for synchronizing signals transferred in series from the master unit 5 to each unit via the synchronizing signal line 49. The timing at which the machine is operated is determined by the synchronizing signal. Unlike the safety information line 42, the FSD output line 48 and the synchronizing signal line 49 do not include a return line and send a stop signal and a synchronizing signal respectively from the master unit 5 to the end unit 12. According to the described configuration, the connectors connected between the units can be made common and the number of pins can be decreased. In the example in FIG. 5, the additional input units 6 and the additional output units 16 are connected alternately between the master unit 5 and the end unit 12, but the invention is not limited to the example; the additional input units 6 and the additional output units 16 would be able to be connected at any desired positions between the master unit 5 and the end unit 12. For example, in a configuration in which the master unit is provided with an input connector and an output connector and an additional input unit is connected to the input connector and an additional output unit is connected to the output connector with the end unit connected to the end faces of the units, the connection state and placement (layout) are restricted. Since the number of units varies depending on the number of safety components and external connected machines, it is possible that the units cannot well be placed depending on the placement space. According to the described embodiment of the invention, the additional input units 6 and the additional output units 16 can be mixed on the same line, so that the restriction on the placement is decreased and a flexible layout is made possible. Further, the flexibility of the layout makes it possible to use the space efficiently and can also contribute to miniaturization of the system. [Non-Safety Information Line 52] On the other hand, the circuit shown in FIG. 5 includes a non-safety information line 52 for sending non-safety information concerning safety information in addition to the safety information line 42. The non-safety information line 52 is indicated by the chain line in FIG. 5. It is an information signal line of the safety relay system; for example, an RS485 communication line, etc., can be used. [Non-Safety Information] The non-safety information includes, for example, ON/OFF information of each safety component connected to the master unit 5 and the additional input units 6, the error state and error information of each unit, output information of the master unit 5 and the additional output units 16, information concerning the actual output state concerning setting of OFF delay, etc., of the additional output unit 16, information concerning the actual input state in a state in which the safety component is invalidated in manual mode, maintenance mode, or mute mode of each additional input unit 6, setup information of each unit such as DIP switch information, ID information concerning the unit ID number assigned to each unit, status information, and the like. The status information includes ON/OFF of a stop signal, unit error information, etc. The term “non-safety information” throughout the specification is used to mean information which does not fall under safety information requiring special specifications on the standard although it is information concerning safety information. Therefore, the non-safety information can include information concerning safety information and safety information itself although the name involves non-safety. However, the non-safety information cannot be included in the safety information. To assign the ID number to each unit, any already known method or a method developed in the future can be used. For example, the following method can be used: A signal line to assign the ID number is added, the ID number is assigned to a unit in the connection order from the signal line, the ID number is transferred to the following unit, the increased ID number is assigned, and the ID number is further transferred to the following unit to increase the ID number each time one unit is passed through. [Information Display of Area Sensor During Mute Mode] Output information of an area sensor during the mute mode can also be displayed as the non-safety information. Some area sensors of a light curtain, etc., include a mute function. For example, when a robot arm turns, if it touches a light curtain, the mute function is set to ON at the timing at which the arm turns for temporarily making ineffective output of the safety component of the light curtain. When the mute function is effective, the function of the light curtain becomes ineffective and if a light shield state is entered, safety output is not set to OFF. However, although the mute mode can be displayed with the mute function set to ON, whether or not light is actually shielded on the light curtain cannot be checked. Then, non-safety information for outputting the light incidence or light shield state of the light curtain even during the mute mode is provided for the light curtain side or the relay unit for controlling the light curtain, whereby display and control can be performed based on the non-safety information. For example, it is made possible to display the light shield state of the light curtain on a monitor and send information to a PLC, etc., for controlling the apparatus, etc. Likewise, error information of each unit, etc., is output to an external system, whereby maintenance can be improved. Specifically, the mute mode and the light incidence/shield state are always monitored in the light curtain or the relay unit for controlling the light curtain. An interface is provided that can output information to a controller for controlling the machine operation of the PLC, etc., in addition to output of safety information for controlling ON/OFF of the external connected machines actually. The non-safety information line 52 is provided separately from the safety information line 42 for handling the safety information to separate the safety information and the non-safety information. The safety information may be fed back into the non-safety information, but the non-safety information is not fed back into the safety information. Accordingly, the safety information is completely separated and is handled independently without receiving the effect from the non-safety information. In other words, if some anomaly occurs in a circuit for handling the non-safety information, a circuit for handling the safety information is not affected and the safety of the system is maintained. Consequently, only the circuit for handling the safety information is duplexed and the self-check function is added thereto as required, whereby the safety standard defined in IEC 61508-27.4.2.3, etc., and on the other hand, the non-safety circuit for handling the non-safety information need not be provided with the specifications and thus can be configured comparatively simply. Further, a configuration in which the safety information and the non-safety information are handled at the same time requires strict specifications so long as the safety information is handled. However, as the safety information and the non-safety information are separated, only the circuit for handling the safety information needs to satisfy the required specifications, so that the system configuration can be simplified. This means that design change of the system can also be made flexibly and the necessity for again designing the safety circuitry can be eliminated for facilitating the design. In addition, as the non-safety information is added, when trouble occurs, the system can be easily recovered from the trouble, etc.; the ease-of-use of the system on the operation thereof can be improved. For example, the part where safety cannot be checked and the trouble occurrence part can be determined, the description of an anomaly can be displayed, and a recovery procedure can be guided. In the relay unit used with a safety relay system in a related art, only ON/OFF information of apparatus is output as safety information because of the limitations of the specifications to comply with the safety standard. In other words, whether or not safety can be checked as a whole is only determined and the input state of an individual safety component cannot be checked. If safety can be secured, the location where safety cannot be checked cannot be determined and the cause cannot be detected. The cause cannot automatically be determined and the system recovery work is extremely difficult to conduct. If the input state of each safety component cannot be grasped when trouble occurs, the cause cannot be determined and the system cannot be recovered from the trouble. Considering the maintenance of the system, it is desirable that the state of each safety component should be checked. As the information is monitored, maintenance can be conducted efficiently and the time can be shortened. Then, the safety information and the non-safety information are separated, whereby it is made possible to use the non-safety information without using a complicated circuit. Generally, a system containing a machine, a robot, etc., includes a plurality of safety components such as an emergency stop button, a safety door, and a light curtain. As the input state of each safety component is checked as non-safety information, when a state in which safety of the system cannot be checked is entered, information is output for determining which safety component is the cause of making it impossible to check safety of the system. For example, the state of each unit such as ON/OFF information of the safety component connected to each additional input unit 6, etc., and unit error information is sent through a non-safety control section 54 to the master unit 5. The master unit 5 collects non-safety information in a master unit non-safety control section 53 and outputs the collected non-safety information to an external system from a non-safety information interface 55. This signal is input to an external PLC, etc., for display, so that it is useful for recovering the system from trouble when trouble occurs. The non-safety information does not directly relate to determination of safety or non-safety, namely, safety securing and is useful information concerning system recovery; the most of the information can be made for recovering the system more rapidly. [Common Line] The safety information line 42 can also be made a common line as shown in FIG. 6 in addition to the mode in which it is separated into the safety input line 43 and the safety output line 44 as in FIG. 5. Accordingly, an input safety control section signal and an output monitor circuit signal can be handled on the same bus. The safety information line 42 with safety input and safety output as a common line includes a straight through line from the master unit 5 to the end unit 12 and a return line returned from the end line 12. In the example in FIG. 6, the safety information line 42 is the through line from a master unit safety control section 47 of the master unit 5 to the end unit 12 and is reversed at the end unit 12, and the safety control sections 46 of the additional output units 16 and the safety control sections 45 of the additional input units 6 are connected on the return line. The safety control sections 45 and 46 and the master unit safety control section 47 of the master unit 5 transfer the safety information. Each additional input unit 6 and each additional output unit 16 recognize a signal from the unit connected at the preceding stage on the return line or the end unit 12 and operate. The additional input unit 6 adopts safety input from the safety component connected to the additional input unit 6 and safety input transferred from the preceding stage as safety input in the safety control section 45 and sends the safety input to the additional input unit 6 at the following stage in order for transferring the safety input to the master unit 5. The additional output unit 16 generates safety check information in the safety control section 46 based on safety check information to check the normal state of the additional output unit 16 and safety check information of the additional output unit 16 connected at the preceding stage on the return line, and transfers the generated safety check information to the additional output unit 16 at the following stage. The safety control section 46 of the additional output unit 16 extracts safety check information transferred from the additional output unit 16 at the preceding stage or the end unit 12 from the signal transferred on the return line, and transfers the extracted safety check information. In other words, the safety input concerning the additional input unit 6 is allowed to pass through. On the other hand, the safety control section 45 of the additional input unit 6 extracts the safety input signal transferred from the additional input unit 6 at the preceding stage or the end unit 12, and transfers the safety input to the additional input unit 6 at the following stage. Thus, on the safety information line 42 with safety input and safety output as a common line, each of the safety control sections 45 and 46 selects a necessary signal and an unnecessary signal is transferred as it is, so that various signals can be mixed on the same line. Safety input and safety check information similar to those previously described with reference to FIG. 5 are also applied as the safety input and safety check information transferred on the safety information line 42 in FIG. 6, and further FSD output line 48 and synchronizing signal line 49 can also adopt the same configuration as that previously described with reference to FIG. 5. In the described configuration, the non-safety information of each unit is transferred in order via the non-safety information line 52 and finally reaches the master unit 5. The master unit 5 receiving the non-safety information includes a non-safety information output section 56 for performing display and external output based on the non-safety information. The non-safety information output section 56 can use a monitor for externally displaying the non-safety information intact or after processed, an interface for externally outputting the non-safety information intact or after processed, and the like. For example, the safety state of each safety component is displayed on the monitor, occurrence of an error and ON/OFF of each external connected machine are displayed, the part where safety cannot be checked is blinked, and the information is sent to the machines such as PLC. In the example in FIG. 7, a non-safety information display section 57 for producing monitor display and a non-safety information interface 55 of external input/output terminals, etc., are included as the non-safety information output section 56. However, the non-safety information output section 56 is not limited to installation in the master unit 5 and instead or in addition, it can also be provided in a unit. As a plurality of non-safety information output sections are provided, it is also made possible to transfer non-safety information between the non-safety information output sections. To install the non-safety information output section in a unit, non-safety information can be used in the non-safety information output section of the unit, so that the bus for transmitting non-safety information to any other unit and the master unit can be made unnecessary. Next, handling of non-safety information separated from safety information will be discussed with reference to FIG. 7. In the figure, the configuration with the safety information line 42 with safety input and safety output as a common line previously described with reference to FIG. 6 is adopted, and the connection portion of the master unit 5, the additional output unit 16, and the additional input unit 6 is shown. In the example, also in the master unit 5, the safety component 1 and the safety relay output section 58 are connected to the master unit safety control section 47. The master unit 5 functions as additional input unit 6 and additional output unit 16. However, either or both of the members may be omitted in the master unit, needless to say. Safety information is sent from the master unit safety control section 47 of the master unit 5 through the safety information line 42 indicated by the solid line arrow in FIG. 7 to the end unit (not shown in FIG. 7) on the through line (alternate long and short dashed line in FIG. 7). The safety information line 42 becomes the return line in opposite direction at the end unit for returning safety information from the end unit through the safety control section 45 of each unit to the master unit safety control section 47. At this time, safety input is acquired from the safety component connected to the safety control section 45 of the additional input unit 6. Each safety control section 45 generates new safety input based on safety input sent from the unit at the preceding stage and safety input of the safety component connected to the safety control section 45, and sends the generated safety input to the additional input unit 6 at the following stage. Thus, the safety input is sent in order from the master unit 5 through the safety control section 45 to the additional input unit 6 and finally is returned to the master unit safety control section 47. For example, as all safety inputs are performed AND operation together, if safety input cannot be obtained in any safety component, namely, if safety cannot be checked, safety output is not set to ON and the relay is opened for stopping the operation of a predetermined external connected machine. On the other hand, the safety information line 42 also handles safety output and specifically the relay for controlling the operation of an external connected machine is opened/closed in the safety relay output section 58. The safety relay output section 58 opens/closes the relay directly or via a contactor, etc. Such a relay, contactor, etc., is contained in or connected to the safety relay output section 58. The master unit safety control section 47 of the master unit 5 outputs safety output based on safety input and sends safety output to the safety relay output section 58 to turn ON/OFF the operation of each external connected machine. In each additional output unit 16, the safety relay output section 58 is connected to the safety control section 46. FIG. 8 shows a state in which the safety control section 45, 46 is implemented as an AND circuit as an example for implementing the configuration in FIG. 7. The safety control section 45, 46 shown in FIG. 8 performs AND operation for the signal sent from the unit at the preceding stage through the safety information line 42 and the signal of the unit containing the safety control section 45, 46 and sends the AND operation result to the following stage as new output. For example, the additional input unit 6 performs AND operation for output of the safety component 1 connected to the additional input unit 6 and output from the additional input unit at the preceding stage and sends the AND operation result to the following stage as new safety input. Accordingly, if safety cannot be checked in any one of the safety components 1 connected to the additional input unit 6, safety cannot be obtained and safety output is set to OFF for stopping the operation of the corresponding external connected machine. The additional output unit 16 performs AND operation for output of a safety check information output section 23 for checking the safety state of the additional output unit 16 and output of the additional output unit at the preceding stage by the safety control section 46, whereby if safety cannot be checked in any one of the additional output units, safety output is set to OFF for stopping the operation of the corresponding external connected machine. For example, the error signal of the additional output unit at the preceding stage and the error signal of the additional output unit are performed AND operation together and unless the normal operation can be checked in all additional output units 16, safety output cannot be obtained, so that safety can be secured. The non-safety information of more detailed information concerning the safety information is transferred separately from the safety information. In the example in FIG. 7, the non-safety information is transferred over the non-safety information line 52, a separate signal line from the safety information line 42. The non-safety information line 52 is installed from the master unit non-safety control section 53 of the master unit 5 to the end unit, and the non-safety control sections 54 of the additional input unit 6 and the additional output unit 16 are connected on the non-safety information line 52 so that they can communicate with each other. Each of the non-safety control sections 54 includes the non-safety information display section 57 and the non-safety information interface 55 as the non-safety information output section 56. The non-safety information display section 57 displays non-safety information to visually provide the user with detailed information concerning safety information. To display the information, text, an image, a moving picture, voice, and the like can be used in combination as required. Accordingly, when an event where safety cannot be checked occurs, the location and the cause of the event can be displayed for notifying the user of the event. The non-safety information interface 55, which is I/O concerning non-safety information, can output non-safety information to an external machine, can obtain the necessary information and operation result from the external machine, can acquire processed and refined non-safety information and cause the non-safety information display section 57 to display the non-safety information, and can send the information to the non-safety control section 54 for sending data to another unit. In the example in FIG. 7, each of the master unit 5, the additional input unit 6, and the additional output unit 16 includes the non-safety information display section 57 and the non-safety information interface 55. However, a unit including only either of the non-safety information display section 57 and the non-safety information interface 55 and a unit including a different non-safety information output section may be mixed The non-safety control section 54 obtains safety information from the safety control section 45, 46, monitors the safety state, and causes the non-safety information display section 57 to display the safety information. However, the non-safety control section 54 does not send obtained information to the safety control section 45, 46. Accordingly, the safety information is not affected by the non-safety information. In other words, if a problem occurs in a circuit concerning non-safety information, the problem does not affect the safety circuitry and the reliability of the safety system is held. Thus, a circuit concerning non-safety information more detailed than simple safety information can be added to the safety relay system while the specifications required for the safety system are met, and moreover the added non-safety circuitry has no effect on the safety information and therefore need not satisfy the specification required for the safety circuit. Thus, comparatively flexible design is made possible and a safety system that can accomplish advanced information display, etc., can be realized. The added circuit is designed independently of the safety circuit, so that there is also the advantage that design change can be made comparatively easily. [Rating Declaration] A rating declaration part can be provided on a side of the end unit. For example, a machine receiving certification of CE marking, EMC service, etc., may be obliged to provide predetermined declaration of the mark of the certification authority, power consumption, etc. Generally, a method of putting a seal of rating declaration on the case of an apparatus, printing, marking, etc., is adopted. However, the standard requires that a declaration part of a predetermined size be provided in a portion of the outside of the apparatus that can be seen by the user, and miniaturization of the apparatus may be inhibited as the declaration space is reserved and depending on where the declaration space is located. Then, in the described safety relay system, a rating declaration part is provided on a side of the end unit, so that necessary declaration can be made using the space. Particularly, the end unit is always connected to the end face, so that an empty space can be provided on the opposite face of the end unit to the connection face although an intermediate connected unit has faces hidden as another unit is added. Then, declaration is made using the space, so that the necessary declaration can be provided without sacrificing the space of another unit. To join a plurality of units, the end unit fixed onto the end face forms a part of the apparatus and thus can provide a mode in which direct indication is made on the apparatus, and the declaration obligation can be fulfilled. This configuration eliminates the need for providing rating declaration on another unit, so that the rating declaration space of each unit can be decreased, contributing to miniaturization of the unit. If the function of the end unit is incorporated in the additional input unit or the additional output unit, the rating declaration part can also be provided on a side of the additional unit incorporating the end unit. As described above, according to the safety relay system of the invention, information relevant to safety information, such as the state of each safety component, can be used as non-safety information and the safety information and the non-safety information are separated from each other, so that the circuit for handling the non-safety information can be prevented from affecting the safety information, and safety can be secured. Accordingly, a circuit concerning the non-safety information can be added to a safety circuit for easily performing maintenance work, etc. Since the safety circuitry and the non-safety circuitry are separated from each other, a complicated circuit configuration to secure safety is not required and the circuitry can be simplified and the non-safety circuit can be added to the safety circuit for rapidly and easily monitoring the system and recovering the system from trouble when trouble occurs. This application claims foreign priority based on Japanese patent application JP 2003-186908, filed on Jun. 30, 2003, the contents of which is incorporated herein by reference in its entirety.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention Th present invention relates to a high-reliability safety relay system suited for use, for example, to drive a target load only if a plurality of input conditions concerning safety check, etc., all hold. 2. Description of the Related Art A safety measure apparatus is used from the necessity for a safety measure in various quarters. For example, a machine tool, a pressing machine, a robot, a packing machine, an elevator, and the like are used at a manufacturing location, and various safety measures become necessary to protect workers from the machines, the apparatus, etc. For example, when an anomaly occurs, power supply to the machine is cut off, thereby stopping the mechanical operation for securing safety for workers. To construct such a system, a safety relay apparatus is used. The safety relay apparatus opens and closes electrical contacts to control energization. Some safety relay apparatus, for example, contain a plurality of relays each with a forcible guide and also include a self-holding function, duplexing of relay contacts, a back check function based on relay NC contacts, a heterostructure, and the like. The relay with a forcible guide is a relay of the type wherein when one normally open contact (NO) is welded, a different normally closed (NC) contact becomes open in a coil non-excitation state and when one normally closed contact is welded, a different normally open contact becomes open in a coil excitation state (for example, JP-A-11-162317). The self-holding function is a function intended so as not to restart the system if safety information is entered by operating an emergency stop switch, etc., for example, and then the state is restored (reset). Further, the duplexing of relay contacts is also called redundancy; as contacts are provided in parallel, if one contact is welded, it is made possible to provide function by another contact provided in parallel. Further, the back check function based on relay NC contacts is a function for detecting a failure of contact welding, etc., of a relay or a contactor and checking the contact state. The heterostructure (diversity structure) is a structure wherein as different types of members are used in combination, even if trouble of a bug, etc., occurs in a specific member, if the trouble is proper to the type, the same trouble does not occur at the same time and therefore it is made possible to provide function by another member. In recent years, the number of countries and regions in which the safety measure standard is made a legal requirement has increased and particularly a safety relay apparatus or system of the specifications compliant with such a safety measure standard has grown in demand. As the safety standards, ISO, IEC, EN, JIS, and the like are defined in response to the standard targets and regions. Particularly, demands for machine safety are enhanced receiving “guidelines for comprehensive safety standard of machines” notified by the Ministry of Health, Labour and Welfare in June 2001, ISO12100, and execution schedule of putting ISO12100 into JIS. For example, to receive certification of category 4, the highest safety level based on EN954-1 of a standard concerning machine safety of the European standards, a redundant structure, a heterostructure, always making self-inspection of data for maintenance of circuitry or parts, and the like are required. FIG. 9 shows a configuration example of a system for stopping a machine with one safety component to secure safety. The safety component is an element for sending a command for cutting off power supply to any desired machine upon reception of specific operation to secure safety of workers. For example, it corresponds to output of an emergency stop button for the worker to stop the operation of a drive motor for a tooling change, teaching, or adjustment of a machine, output of a safety door switch for detecting a safety door being released to allow the worker to enter the work area of a machine, output of a light curtain for optically detecting the worker approaching a dangerous area, or the like. A safety component 1 is used with a safety output unit 2 for implementing a safety relay apparatus in combination to make up a safety circuit. A safety component switch 3 of normally closed break type is connected to the safety circuit shown in FIG. 9 . When the safety circuit is closed, the safety output unit 2 determines that the state is normal, and closes a relay 4 for maintaining power supply to the connected machine. On the other hand, if the safety circuit is opened as the safety component switch 3 is operated manually by the worker or the user or is operated according to output of a sensor, etc., the safety output unit 2 determines that the state is unsafe, and releases the relay 4 for cutting off power supply to the connected machine to stop the operation thereof. To provide the system with redundancy, a dual-redundant safety circuit made up of two safety circuits is formed as shown in FIG. 9 and as the safety component switch 3 is operated, both safety circuits are opened. Accordingly, if one of the safety circuits becomes defective or fails due to contact welding, etc., the other safety circuit functions, so that the machine can be stopped. Further, self-inspection is made, whereby an anomaly of contact welding, etc., can be detected and accumulating of failures can be prevented. The system also adopts a heterostructure for preventing the same defectiveness from occurring at the same time. To make the apparatus or system compliant with the various standards including EN954-1, etc., described above, it is necessary to duplex the circuitry for handling safety information and provide a self-check function and generally the circuit design becomes complicated. On the other hand, even if the system is configured so as to be able to check the safety state by duplexing the circuitry, etc., if the cause, location, etc., of an accident when the system becomes down cannot be detected or determined without any measure. Since the cause of the accident needs to be removed to recover the system, it is desirable that the cause and the location of the accident should be able to be detected to recover the system early. Thus, a circuit for outputting or displaying various pieces of information for facilitating safety check and danger detection may be added to an input unit to which a safety component is connected or a safety output unit to which a safety relay is connected. For example, detailed information concerning safety information, such as the state of the safety component and error information, can be added for easily determining trouble, etc. However, if such detailed information concerning safety information is used as safety input, the circuit for handling the information also requires facilities of duplexing, self-check, etc., for safety, and the circuitry becomes furthermore complicated; this is a problem. If design change occurs in the system, construction of the safety system responsive to the design change needs to be again designed, and the job is extremely intricate. Construction of the system compliant with the condition to receive standard certification is urgently required particularly under the present circumstances in which extreme importance tends to be placed on reception of certification of various safety standards combined with making the safety standard a legal requirement and the demands for the safety measures in recent years.
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<SOH> SUMMARY OF THE INVENTION <EOH>It is an object of the invention to provide a safety relay system for making it possible to add non-safety information relevant to safety information without affecting the safety information for easily maintaining, recovering, redesigning, etc., the safety system. To the end, according to a first aspect of the invention, there is provided a safety relay system for acquiring safety input from one or more safety components, checking a safety state, if safety is checked, outputting safety output for opening/closing a safety relay to enable an external connected machine connected to the safety relay to operate and on the other hand, if it is determined that the state is unsafe, opening/closing the safety relay to directly or indirectly stop the operation of at least a hazardous part in the external connected machine, the safety relay system including one or more additional input units for sending safety input from the safety component; a master unit for receiving the safety input from the additional input unit and providing safety output to operate the safety relay based on the safety input; a safety information line for transferring safety information between the units; a non-safety information line for transferring non-safety information separate from the safety input, the non-safety information being information concerning the operation state of each safety component or each unit; and a non-safety information output section for outputting the non-safety information transferred on the non-safety information line. The safety information transmitted on the safety information line is not affected by the non-safety information transmitted on the non-safety information line and safety output of the master unit operates based on the safety information transmitted on the safety information line and does not depend on the non-safety information on the non-safety information line. Accordingly, the state of each safety component, error information, and the like can be transmitted to the master unit according to the non-safety information, and it is made possible to rapidly recover the system from trouble based on the information. As the non-safety information is separated from the safety information and is sent on the separate line, the circuit of the non-safety information can be simplified. The non-safety information has no effect on the safety information, so that the advanced safety standard can be met without affecting the reliability of the circuit concerning the safety information. The safety relay system according to a second aspect of the invention is characterized by the fact that in the safety relay system of the first aspect, each additional input unit includes a non-safety control section for communicating the non-safety information, and the non-safety information is transferred to each adjacent unit in order, whereby each additional input unit communicates with the master unit. The safety relay system according to a third aspect of the invention is characterized by the fact that in the safety relay system of the first aspect, each additional input unit includes a non-safety control section for communicating the non-safety information, and each additional input unit communicates directly with the master unit. The safety relay system according to a fourth aspect of the invention is characterized by the fact that the safety relay system in any of the first to third aspects further includes an end unit being connected to one end of the one or more additional input units for causing the master unit to detect the number of the connected additional input units. The safety relay system according to a fifth aspect of the invention is characterized by the fact that the safety relay system in any of the first to fourth aspects further includes the one or more additional output units for receiving safety output from the master unit and operating the safety relay based on the received safety output. The safety relay system according to a sixth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to fifth aspects, the one or more-additional input units and the one or more additional output units are connected to the safety information line for enabling the additional input units to communicate safety input to each other and the additional output units to communicate safety output to each other. The safety relay system according to a seventh aspect of the invention is characterized by the fact that in the safety relay system in the fifth or sixth aspect, the safety information line connects the one or more additional input units and the one or more additional output units as the same line for enabling the safety input and the safety output to be communicated between each unit and the master unit. The safety relay system according to an eighth aspect of the invention is characterized by the fact that in the safety relay system in the fifth or sixth aspect, the safety information line is connected via a connector provided on each unit and either of the additional input unit and the additional output unit can be connected to the same connector. The safety relay system according to a ninth aspect of the invention is characterized by the fact that in the safety relay system in the eighth aspect, the safety information line includes a safety input line and a safety output line and the safety input line is connected to the additional input unit for sending safety input and the safety output line is connected to the additional output unit for sending safety output. The safety relay system according to a tenth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to ninth aspects, the safety information line is a serial line. The safety relay system according to an eleventh aspect of the invention is characterized by the fact that in the safety relay system in any of the first to tenth aspects, each additional input unit includes a safety control section for performing AND operation for safety input transmitted via the safety information line from the additional input unit connected to the preceding stage of that additional input unit and safety input from the safety component connected to that additional input unit and outputting the AND operation result as safety input. The safety relay system according to a twelfth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to ninth aspects, the safety information line is parallel lines and when safety input is transmitted straightly from the master unit through the additional input units to the end unit and then is transmitted from the end unit to the master unit, each time the safety input passes through each of the additional input units, a shift is made on the parallel line to transmit the safety input, and the number of the connected additional input units can be detected based on which parallel line the safety input received at the master unit is detected from. The safety relay system according to a thirteenth aspect of the invention is characterized by the fact that the safety relay system in any of the first to twelfth aspects further includes a power unit being connected to the master unit for supplying power to the safety relay system. The safety relay system according to a fourteenth aspect of the invention is characterized by the fact that in the safety relay system in any of the fourth to thirteenth aspects, a rating declaration part is provided on a side of the end unit. The safety relay system according to a fifteenth aspect of the invention is characterized by the fact that in the safety relay system in any of the fifth to fourteenth aspects, at least either the additional input unit or the additional output unit includes a non-safety information display section for externally displaying non-safety information and a non-safety information interface for sending non-safety information to an external machine. The safety relay system according to a sixteenth aspect of the invention is characterized by the fact that in the safety relay system in any of the first to fifteenth aspects, the non-safety information includes at least any of ON/OFF information of the safety component connected to the master unit or each additional input unit, an error state and error information of each unit, output information of the master unit or the additional output unit, operation mode information of each additional input unit, or setup information of each unit.
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20040630
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20080812
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20050324
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79939.0
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AMRANY, ADI
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AUTOMOTIVE SAFETY RELAY SYSTEM IMPLEMENTATION
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UNDISCOUNTED
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ACCEPTED
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10,881,209
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ACCEPTED
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ROI selection in image registration
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A method and system is presented for automatically selecting a region of interest (ROI) within an image of an object, for example when performing non-rigid image registration between the image and another image of the object. In this way, the need for user interaction can be minimized or eliminated during image registration. The ROI is determined by defining an entropy measure H of the image, and selecting the region within the image in which the entropy measure is maximized, In this way, the ROI is optimized to contain as much information as possible. In one embodiment, the entropy measure H is a modified Shannon entropy, defined by H=−ΣI P(I) log P(I), where I is the value of the image intensity level, and P(I) is the probability of an image intensity value I occurring within the ROI.
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1. A method of selecting an ROI (region of interest) within an image of an object, the method comprising: defining a measure H of the image, the measure H being suitable for registering the image with another image of the object; maximizing the measure H; and selecting the ROI by determining the region within the image in which the measure H is maximized. 2. A method in accordance with claim 1, wherein the measure H comprises image entropy. 3. A method in accordance with claim 2, wherein the image comprises a digital image including a plurality N of pixels, each pixel being characterized by an associated pixel value that represents the image brightness of a corresponding unit of the object. 4. A method in accordance with claim 3, wherein the entropy measure H is a modified Shannon entropy measure defined by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 5. A method in accordance with claim 1, wherein the object comprises an anatomical region, and wherein the anatomical region comprises at least one reference structure and at least one treatment target. 6. A method in accordance with claim 5, wherein the ROI contains the at least one treatment target. 7. A method in accordance with claim 1, wherein the acts of defining the measure H, maximizing the measure H, and selecting the ROI by determining the region within the image in which H is maximized, are performed automatically by a processor without interaction from an operator. 8. A method of selecting an ROI (region of interest) within a first image of an object so that the ROI can be registered with a second image of the object, the method comprising: a) calculating a measure H of the ROI; and b) selecting an ROI within the first image in which the measure H is maximized. 9. A method in accordance with claim 8, wherein the measure H comprises image entropy. 10. A method in accordance with claim 9, wherein the first image comprises a plurality of pixels, each pixel having an associated pixel value that represents the image brightness of a corresponding unit of the object. 11. A method in accordance with claim 10, wherein the entropy measure H is a modified Shannon entropy measure given by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 12. A system for selecting an ROI (region of interest) within an image of an object, the system comprising: a) a measure calculator configured to calculate a measure H of the image; b) a measure maximizer configured to maximize the measure H; and c) a controller configured to select an ROI within the image in which the measure H is maximized. 13. A system in accordance with claim 12, wherein the measure H comprises an entropy measure H representative of the image entropy. 14. A system in accordance with claim 13, wherein the image comprises a plurality of pixels, each pixel having an associated pixel value that represents the image intensity of a corresponding unit of the object; and wherein the measure calculator comprises an entropy calculator configured to input and store the pixel values, and to compute, for each pixel value, the probability of the pixel value occurring within an ROI; and wherein the entropy measure H is a modified Shannon entropy measure, and is given by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 15. A system for selecting an ROI within a first image of an object so that image registration can be performed within the ROI between the first image and a second image of the object, the system comprising: a) an entropy calculator configured to calculate an entropy measure H of the first image; b) an entropy maximizer configured to maximize the entropy measure H; and c) a controller configured to select an ROI within the first image in which the entropy measure H is maximized. 16. A system in accordance with claim 15, wherein the object comprises an anatomical region including a treatment target and one or more reference structures. 17. A system in accordance with claim 15, wherein the first image comprises a DRR reconstructed from preoperative 3D scan data of the anatomical region; and the second image comprises an intraoperative 2D x-ray image of the anatomical region generated in near real time. 18. A system in accordance with claim 16, wherein each image comprises a plurality of pixels, each pixel having an associated pixel value that represents the image intensity of a corresponding unit of the object. 19. A system in accordance with claim 18, wherein the entropy calculator is configured to input and store the pixel values, and to compute, for each pixel value, the probability of the pixel value occurring within an ROI; and wherein the entropy measure H is a modified Shannon entropy measure, and is given by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 20. A system in accordance with claim 15, wherein the controller is configured to select the ROI so that at least a portion of the treatment target is included within the ROI. 21. A system in accordance with claim 15, wherein the image registration comprises a non-rigid image registration based on a non-rigid deformation of the object between the acquisition of the first image and the acquisition of the second image. 22. A system for selecting an ROI within a first image of an object so that image registration can be performed within the ROI between the first image and a second image of the object, the system comprising: means for calculating an entropy measure H of the first image; means for maximizing the entropy measure H; and means for selecting an ROI within the first image in which the entropy measure H is maximized. 23. A system in accordance with claim 22, wherein the entropy measure H is a modified Shannon entropy measure, and is given by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 24. A computer-readable medium having stored therein computer-readable instructions for a processor, wherein the instructions, when read and implemented by the processor, cause the processor to: input and store data representative of the intensity values of the pixels of an image; calculate using the input data an entropy measure H of the image; and select an ROI within the image in which H is maximized. 25. A computer-readable medium in accordance with claim 24, wherein the entropy measure H is a modified Shannon entropy measure, and is given by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 26. An image registration system for registering at least one 2D image of an anatomical region with previously generated 3D scan data of the anatomical region, the anatomical region including at least one treatment target and at least one reference structure, wherein the 2D image is generated in near real time by detecting one or more radiographic imaging beams after the imaging beams have traversed at least a portion of the anatomical region, the imaging beams having known intensities and known positions and angles relative to the anatomical region, the system comprising: means for providing the 3D scan data of the anatomical region; a scan data modifier configured to modify the 3D scan data so as to compensate for a difference between the ratio of bone-to-tissue attenuation at the energy level of the 3D scan, and the ratio of bone-to-tissue attenuation at the energy level of the imaging beam used for the near real-time 2D image; a DRR generator configured to generate at least one DRR (digitally reconstructed radiograph) of the anatomical region, using the 3D scan data and the known locations, angles, and intensities of the imaging beams; an ROI selector configured to select an ROI (region of interest) within the DRR, the ROI including the image of the treatment target and of the reference structure; a motion field generator configured to generate a 3D full motion field within the ROI by estimating a plurality of local motion fields within the ROI; and a parameter determiner configured to determine from the 3D full motion field a set of non-rigid transformation parameters that represent the difference in the position and orientation of the treatment target as shown in the 2D image, as compared to the position and orientation of the treatment target as shown in the DRR. 27. A system in accordance with claim 26, wherein the 3D scan data comprise a plurality of CT numbers representing the image intensity of corresponding 3D CT voxels, each CT voxel representing a corresponding volume element of the anatomical region; wherein each CT voxel is disposed within one of a plurality of axial voxel slices, each axial voxel slice representing a corresponding axial slice of the anatomical region; wherein each CT number represents the attenuated intensity of an x-ray CT beam that has been generated at a CT scan energy level and that has traversed the corresponding volume element of the anatomical region 28. A system in accordance with claim 27, wherein the scan data modifier includes a processor for performing on each CT number a mathematical operation derived from a non-linear x-ray attenuation model; and wherein the mathematical operation is given by: C(x,y,z)=a C0(x,y,z)ebC0(x,y,z) where C(x,y,z) represents the modified CT number of a 3D CT voxel having a location (x,y,z); a and b represent weighting coefficients; and C0(x,y,z) represents the un-modified CT number, based on a linear attenuation model, of a 3D CT voxel having a location (x,y,z). 29. A system in accordance with claim 26, wherein the motion field generator comprises: a mesh grid generator configured to generate in the first image a mesh grid having a plurality of mesh nodes; a nodal motion estimator configured to estimate, for each mesh node in the first image, at least one nodal motion vector that describes a matching of the mesh node with a corresponding mesh node in the second image; and a motion field interpolator configured to determine a local motion vector for each of a plurality of points of interest within the first image, by interpolating from the nodal motion vectors of the mesh nodes that surround each point of interest. 30. A system in accordance with claim 29, wherein the mesh grid generator is configured to repeat, at each of a plurality of mesh resolution levels, the act of generating of the mesh grid; wherein nodal motion estimator is configured to repeat, at each of the plurality of mesh resolution levels, the act of estimating the at least one nodal motion vector for each mesh node; and wherein the nodal motion vectors from which the motion field interpolator interpolates to determine the local motion vector comprise nodal motion vectors that have been estimated at a final one of the plurality of mesh resolution levels. 31. A system in accordance with claim 30, further comprising a motion field reconstructor configured to reconstruct the nodal motion vector for a mesh node if any nodal motion vector estimated for any mesh node is unreliable. 32. A system in accordance with claim 30, wherein at each mesh resolution level, the nodal motion estimator is configured to pass onto a subsequent mesh resolution level one or more nodal motion vectors that have been estimated at the current mesh resolution level. 33. A system in accordance with claim 30, wherein the plurality of mesh levels comprise successively increasing mesh resolution levels, the mesh grid at each successive mesh resolution level having a number of mesh nodes that is greater compared to the number of mesh nodes at each previous mesh resolution level. 34. A system in accordance with claim 33, wherein for the first one of the plurality of mesh resolution levels, the nodal motion estimator is configured to estimate a global translation for the first image and to use the global translation as an estimate for the nodal motion vector for each mesh node in the mesh grid generated for the first mesh resolution level; and wherein the global translation represents a translation of an image center of the first image. 35. A system in accordance with claim 30, wherein at each mesh resolution level subsequent to the first mesh resolution level, the mesh nodes in the first image comprise a first subset of mesh nodes and a second subset of mesh nodes; wherein the first subset of mesh nodes comprise mesh nodes generated at a previous mesh resolution level; and wherein the second subset of mesh nodes comprise mesh nodes that are newly added at the current mesh resolution level. 36. A system in accordance with claim 35, wherein at each mesh resolution level subsequent to the first mesh resolution level, the nodal motion estimator is configured to use the nodal motion vectors passed on from a previous mesh resolution level as estimates for nodal motion vectors for the first subset of mesh nodes; wherein the nodal motion estimator comprises an interpolator configured to interpolate from the nodal motion vectors estimated for the first subset of mesh nodes, to estimate the nodal motion vectors for the second subset of mesh nodes; and wherein the nodal motion estimator further comprises a nodal motion refiner configured to refine, for each mesh node in both the first and the second subsets, the nodal motion vector that was estimated for the mesh node. 37. A system in accordance with claim 36, wherein the nodal vector refiner is configured to: define a block centered on a mesh node in the first image; search for a matching mesh node in the second image that maximizes a similarity measure between the block in the first image and another block centered around the matching mesh node in the second image; and modify the nodal motion vector so that the nodal motion vector describes a mapping of the mesh node in the first image onto the matching mesh node in the second image. 38. A system in accordance with claim 37, wherein the nodal vector refiner is configured to repeat, for each of a plurality of successively increasing image resolution levels, the acts of defining a block centered around a mesh node in the first image, searching for a matching mesh node in the; second image, and refining the nodal motion vector. 39. A method of registering a near real time 2D x-ray image of an anatomical region with 3D scan data representative of a preoperative image of the anatomical region, the anatomical region including at least one reference structure and at least one treatment target, the method comprising: modifying the 3D scan data, and reconstructing from the modified 3D scan data at least one DRR; selecting an ROI (region of interest) within the DRR, wherein the ROI includes at least one structure in the object; generating a 3D motion field by estimating one or more 2D local motion fields within the ROI, and constructing a full 3D motion field from the local motion fields; and determining from the full 3D motion field a set of non-rigid transformation parameters that represent the difference in the position and orientation of the reference structure and the treatment target as shown in the 2D x-ray image, as compared to the position and orientation of the reference structure and the treatment target as shown in the DRR. 40. A method in accordance with claim 39, wherein the anatomical region comprises bone and tissue; wherein the 3D scan data are modified to compensate for a difference between the ratio of bone-to-tissue attenuation at the energy level of the 3D scan, and the ratio of bone-to-tissue attenuation at the energy level of the x-ray imaging beam used for the near real-time x-ray image. 41. A method in accordance with claim 40, wherein the 3D scan data comprise a plurality of CT numbers representing the image intensity of corresponding 3D CT voxels, each CT voxel representing a corresponding volume element of the anatomical region; wherein each CT voxel is disposed within one of a plurality of axial voxel slices, each axial voxel slice representing a corresponding axial slice of the anatomical region; wherein each CT number represents the attenuated intensity of an x-ray CT beam that has been generated at a CT scan energy level and that has traversed the corresponding volume element of the anatomical region 42. A method in accordance with claim 41, wherein the scan data modifier includes a processor for performing on each CT number a mathematical operation derived from a non-linear x-ray attenuation model; and wherein the mathematical operation is given by: C(x,y,z)=a C0(x,y,z)ebC0(x,y,z) where C(x,y,z) represents the modified CT number of a 3D CT voxel having a location (x,y,z); a and b represent weighting coefficients; and C0(x,y,z) represents the un-modified CT number, based on a linear attenuation model, of a 3D CT voxel having a location (x,y,z). 43. A method in accordance with claim 39, wherein the step of defining the ROI comprises: a) calculating an entropy measure H of the DRR; and b) selecting an ROI so as to maximize the entropy measure H. 44. A method in accordance with claim 43, wherein the entropy measure H is a modified Shannon entropy measure given by: H=−Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the image; Imax is the number of image intensity levels; and P(I) is the probability of an image intensity value I occurring within the ROI. 45. A method in accordance with claim 39, wherein the act of generating a motion field comprises: generating in the 2D x-ray image a mesh grid having a plurality of mesh nodes; for each mesh node in the 2D x-ray image, estimating at least one nodal motion vector that describes a matching of the mesh node with a corresponding mesh node in the DRR; and determining a local motion vector for each of a plurality of points of interest within the 2D x-ray image, by interpolating from the nodal motion vectors of the mesh nodes that surround the point of interest. 46. A method in accordance with claim 45, further comprising repeating, at each of a plurality of mesh resolution levels, the acts of generating in the 2D x-ray image a mesh grid having a plurality of mesh nodes and estimating at least one nodal motion vector for each mesh node; and wherein the nodal motion vectors of the mesh nodes that surround the point of interest comprise nodal motion vectors that have been estimated at a final one of the plurality of mesh resolution levels. 47. A method in accordance with claim 46, further comprising: determining whether any nodal motion vector that was estimated for any mesh node is unreliable, and if so, reconstructing the nodal motion vector for the mesh node.
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BACKGROUND Image registration aims at finding an optimal transformation between different representations of one or more objects, i.e. between different images. Registration techniques can be useful in medical procedures in which a pre-operative image space needs to be properly correlated to a real-time physical space. In image-guided surgical procedures, for example, pre-operatively acquired images may have to be registered onto intra-operative, near real-time images. In this way, the surgeon can be guided during his operation by viewing, in real time, images of the anatomical region being treated and/or the surgical devices. In practice, a formal mathematical transformation may be determined that best aligns the pre-operative image coordinate system with the patient's physical world coordinate system, defined for example in the treatment room. The registration of preoperative 3D images onto real-time 2D projection images (e.g. 2D x-ray projection images) is often referred to as “2D-3D image registration.” 2D-3D image registration is widely used in image-guided surgical procedures. Because in general real-time x-ray images are merely 2D projections, the lack of 3D information can hinder accurate surgical guidance. Pre-operative 3D scans (e.g. CT scans or MRI scans) of the target region can provide the necessary 3D information. A robust and accurate 2D-3D registration algorithm is needed in order for the position of the anatomical target (and/or relevant surgical instruments), as viewed on the real-time 2D images, to be reliably correlated to their position as visualized through the pre-operative 3D scans. As one example, during radiotherapy or radiosurgery, 2D-3D registration can be used to properly direct radiation onto a tumorous target that is visible in the images. As another example, in a surgical navigation system, 2D-3D registration can be used to track in real time the changing position of a surgical probe on a display of the preoperative images. A known registration method is to identify corresponding features in each coordinate system. For example, fiducial markers may be attached to or implanted in the patient before the pre-operative images are acquired, for point-based alignment. The markers may be tracked using an optical localization device. Typically, these fiducial markers may be designed so that they can be accurately localized in the pre-operative image as well as in the physical world. The respective localization points may then used to calculate a rigid body transformation between the two coordinate systems. Fiducials-based tracking can be difficult for the patient, for a number of reasons. For example, high accuracy tends to be achieved by using bone-implanted fiducial markers, but less invasive techniques such as skin-attached markers or anatomical positions tend to be less accurate. Implantation of fiducials into a patient may be painful and difficult, especially for the C-spine, the implantation process for which may frequently lead to clinical complications. Therefore, a number of attempts have been made in the art to develop techniques for fiducial-less tracking. These known methods generally assume a rigid body transformation, i.e. a rigid body rotation and a rigid body translation. Such a rigid transformation typically ignores local variations during the transformation, and may assume that the patient's anatomy is a rigid body, and that all of the rigid body constraints should be preserved. A lot of clinical data has shown that the rigid transformation model may be inadequate in many cases. Accordingly, non-rigid registration algorithms may be required in order to account for real patient body deformation, and thus track an anatomical region more precisely. In non-rigid image registration, faster computation may be achieved by restricting the registration process to a region of interest (ROI) within the image being registered. It is known to select such ROIs through user interaction, for example through manual input by the user. The requirement of user interaction is, however, one of the undesirable features of the known fiducial-less tracking methods. It is desirable that a method and system be provided for automatically selecting an ROI within an image, without requiring user interaction. In this way, a fully automated non-rigid image registration could be performed, minimizing or effectively eliminating the need for user interaction during image registration. SUMMARY A method and system are presented for automatically selecting a region of interest within an image of an object. In this way, the need for user interaction can be minimized or eliminated, when performing non-rigid image registration between the image and a different image of the object. The object may be an anatomical region, containing a treatment target and one or more reference structures. The selected ROI contains the treatment target. In one embodiment, the ROI may be selected by defining a measure H of the image, the measure H being suitable for image registration, and selecting the region within the image in which the measure H is maximized. In this way, the ROI can be optimized to contain as much information as possible. In one embodiment, the measure H is an entropy measure, representative of image entropy. In one embodiment, the entropy measure H may be a modified Shannon entropy, defined by: H=Σ=1I=Imax I P(I)log P(I), where I is the value of the intensity of the first image, at each pixel of the first image, Imax is the number of image intensity levels, and P(I) is the probability of an image intensity value I occurring within the ROI. In one embodiment, a computer-readable medium is presented that has stored therein computer-readable instructions for a processor, wherein the instructions, when read and implemented by the processor, may cause the processor to 1) input and store data representative of the intensity values of the pixels of an image; 2) calculate an entropy measure H of the image, using the input data; and 3) select an ROI within the image that maximizes H. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A provides an overall schematic block diagram of a fiducial-less tracking method and system. FIG. 1B illustrates the geometric relations between a three-dimensional treatment target and two orthogonal 2D x-ray projections of the target. FIG. 2 illustrates a schematic flowchart of a non-rigid image registration algorithm used in one embodiment. FIG. 3A schematically illustrates the generation of 2D DRRs from 3D CT scan data of an anatomical region that includes at least one treatment target and at least one reference structure. FIG. 3B is a schematic plot of a non-linear x-ray attenuation model for modifying CT numbers, in order to generate improved quality DRRs. FIG. 4 illustrates exemplary images that have been enhanced to increase the visibility of skeletal structures, using top hat filtering. FIGS. 5A and 5B schematically illustrate local motion estimation for a given point of interest within a target in a patient, using block matching. FIG. 6 schematically illustrates multi-level block matching, in one embodiment. FIG. 7 schematically illustrates a neighborhood R for calculating a similarity measure based on pattern intensity. FIGS. 8A and 8B provide plots of the similarity measure functions used for the local motion estimation illustrated in FIGS. 5A and 5B, respectively. In FIGS. 8A and 8B, the similarity measure functions are plotted with respect to translations in two mutually orthogonal directions (x- and y-). FIG. 9 illustrates global motion estimation between the image center of a DRR and the image center of a corresponding x-ray image. FIG. 10A schematically illustrates a mesh grid established for a DRR of a target region, and a corresponding mesh grid established for an x-ray image of the target region, in an embodiment in which the target is located within the cervical region of the spine. FIG. 10B schematically illustrates a mesh grid established for a DRR of a target region, and a corresponding mesh grid established for an x-ray image of the target region, in an embodiment in which the target is located within the thoracic region of the spine. FIG. 10C schematically illustrates a mesh grid established for a DRR of a target region, and a corresponding mesh grid established for an x-ray image of the target region, in an embodiment in which the target is located within the lumbar region of the spine. FIG. 11 illustrates a hierarchy of meshes for mesh nodal motion estimation, starting from a relatively course mesh and progressing onto finer meshes. FIG. 12 schematically illustrates the passing on of node estimation, from a course mesh resolution level onto a finer mesh resolution level. FIG. 13 schematically illustrates the determination of a motion vector for a point of interest, by interpolation from surrounding nodes. FIG. 14A schematically illustrates, in vectorial form, a full motion field (reconstructed from many estimated local motion vectors), in an embodiment in which the target is located within the cervical region of the spine. FIG. 14B schematically illustrates, in vectorial form, a full motion field (reconstructed from many estimated local motion vectors), in an embodiment in which the target is located within the thoracic region of the spine. FIG. 14C schematically illustrates, in vectorial form, a full motion field (reconstructed from many estimated local motion vectors), in an embodiment in which the target is located within the lumbar region of the spine. FIG. 15 is a schematic block diagram of a motion field generator configured to generate a full motion field during non-rigid image registration of an object, in accordance with one embodiment. FIG. 16 is a schematic block diagram of an apparatus for performing fiducial-less non-rigid image registration, in one embodiment. FIG. 17A schematically illustrates target localization between a DRR of the target and an x-ray image of the target, in an embodiment in which the target is located within the cervical region of the spine. FIG. 17B schematically illustrates target localization between a DRR of the target and an x-ray image of the target, in an embodiment in which the target is located in the thoracic region of the spine. FIG. 17C schematically illustrates target localization between a DRR of the target and an x-ray image of the target, in an embodiment in which the target is located in the lumbar region of the spine. FIG. 18 is a table of TRE (target registration error) values for different targets located within the cervical, thoracic, and lumbar regions, in embodiments in which fiducials are used. FIG. 19 is a table of TRE (target registration error) values for different targets located within the cervical, thoracic, and lumbar regions, in embodiments in which fiducials are removed in CT data. DETAILED DESCRIPTION A method and system is presented for tracking and aligning a treatment target, without using fiducial markers. An intensity-based, non-rigid 2D-3D image registration method and system is performed. Anatomical reference structures, for example skeletal or vertebral structures that are rigid and easily visible in diagnostic x-ray images, are used as reference points, eliminating the need for fiducial markers which must be surgically implanted. The tracking method and system of the present invention is useful in image guided radiosurgery and radiotherapy, and is particularly useful for spinal applications, i.e. for tracking skeletal structures in the body, especially in the regions containing or located close to spinal vertebrae. The method and system of the present invention, however, can also be used in any other application in which there is a need to register one image onto a different image. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the present invention. Some portions of the detailed descriptions that follow are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of acts leading to a desired result. The acts are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussion, it is appreciated that throughout the description, discussions utilizing terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. The present invention can be implemented by an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general purpose computer, selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus. The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the required method. For example, any of the methods according to the present invention can be implemented in hard-wired circuitry, by programming a general purpose processor or by any combination of hardware and software. One of skill in the art will immediately appreciate that the invention can be practiced with computer system configurations other than those described below, including hand-held devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. The required structure for a variety of these systems will appear from the description below. The methods of the invention may be implemented using computer software. If written in a programming language conforming to a recognized standard, sequences of instructions designed to implement the methods can be compiled for execution on a variety of hardware platforms and for interface to a variety of operating systems. In addition, the present invention is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein. Furthermore, it is common in the art to speak of software, in one form or another (e.g., program, procedure, application . . . ), as taking an action or causing a result. Such expressions are merely a shorthand way of saying that execution of the software by a computer causes the processor of the computer to perform an action or produce a result. For radiosurgical treatment of tumorous targets, the task of fiducial-less tracking is to predict patient target movement between pre-operative patient CT scanning and patient radiation treatment, based on the skeletal structures. Target movement is tracked by comparing the pre-operative 3D CT data and intra-operative x-ray 2D projection images, i.e. a 2D/3D image registration is performed. As well known, the basic problem in image registration is to find the optimal transformation that relates different representations or images of the same object. A 2D/3D registration, in particular, seeks to determine a projection mapping or transformation, from a 3D to a 2D coordinate system, such that points in each space which correspond to the same anatomical point are mapped to each other. In one embodiment, the transformation is represented, for example, by a set of non-rigid transformation parameters (dxT, dyT, dzT, r, p, w), where (dxT, dyT, dzT) represent the translations of the object, which may be a treatment target, and (r, p, w) represent global rigid rotations of the target. In one embodiment, two orthogonal x-ray projections are used to solve for these six parameters. In this embodiment, the registration in each projection is performed individually, and the results of the registration for each projection are subsequently combined, to obtain the six 3D transformation parameters. In other embodiments, however, different projections or combinations thereof may be used to solve for the transformation parameters. FIG. 1A provides an overall schematic block diagram of a fiducial-less tracking method and system, in an embodiment of the invention in which the object being tracked is an anatomical region of a patient (e.g. a spinal region), and includes at least one treatment target and at least one reference skeletal structure. In overview, FIG. 1A shows that 2D-3D non-rigid image registration is performed for each of a pair of orthogonal projections A and B. For each projection, digitally reconstructed radiographs (DRRs) are first generated from the 3D CT scan data. As shown in FIG. 1A, the projection images A and B, acquired intra-operatively in near real time, are registered onto their respective DRRs. To determine the change in patient position and orientation between the time of the pre-operative CT scan and the time of radiosurgical treatment, local motion fields (dxA, dyA) and (dxB, dyB) are estimated in 2D, by using similarity measures to compare the pixel intensities in the x-ray images and the DRR images. The 3D motion field is derived from the 2D local motion fields. A full 3D motion field, derived from the local motion fields, includes 3D target translations (dxT, dyT, dzT) and global rigid rotations (r, p, w), which are a set of non-rigid transformation parameters that represent the difference in the position and orientation of the treatment target, as shown in the projection images A and B, as compared to the position and orientation of the treatment target, as shown in the DRRs. FIG. 1B illustrates the geometric relations between a three-dimensional treatment target, and two orthogonal 2D x-ray projections (labeled A and B in FIG. 1B), in an image registration method and system in accordance with the present invention. A pair of cameras (or image receivers) A and B receive their x-ray projections from respective x-ray sources (not shown). In the coordinate system of the 3D scan, the x-axis is directed inward into the paper, and is not indicated in FIG. 1B. As explained above, the change in position of the treatment target is represented by three translations and three global rigid rotations (dx, dy, dz, r, p, w). In FIG. 1B, the orthogonal 2D projections A and B are viewed from the directions oAsA and oBsB, respectively. For each of the projections A and B, FIG. 1B illustrates respective 2D planar coordinate systems that are fixed with respect to the image plane that characterizes each projection. The image planes A and B for the projections A and B are thus defined by mutually orthogonal axes within the respective coordinate systems. These axes are shown in FIG. 1B as (xA,yA) for projection A, and (xB, yB) for projection B. The direction of the axis xA in the 2D coordinate system for projection A, and the direction of the x-axis in the 3D scan coordinate system, are opposite with respect to each other. The direction of axis xB in the coordinate system for projection B, and the direction of the axis x in the 3D scan coordinate system, are the same. For projection A, the 2D motion field (dxA, dyA) is estimated by registering the x-ray image that is projected onto the image plane A, with the corresponding reference DRR image. For projection B, the 2D motion field (dxB, dyB) is estimated by registering the x-ray image that is projected onto the image plane B, with the corresponding reference DRR image. Given the 2D motion fields (dxA, dyA) for projection A, and (dxB, dyB) for projection B, the 3-D target translation (dxT,dyT,dzT), as well as the global rigid rotations (r, p, w), can be obtained for both projections A and B, by a straightforward mathematical operation. FIG. 2 illustrates a flowchart 100 of a non-rigid image registration algorithm. In the illustrated embodiment, the registration algorithm is used for a 2D/3D registration, performed for each projection described in FIG. 1B. In particular, non-rigid image registration is performed in the illustrated embodiment between a 2D DRR (reconstructed from pre-operative CT scan data) of a patient's target region, and an intra-operative (near real-time) x-ray projection image of the target region. It is to be understood, however, that the method and system described in this section can be used in any other type of image registration process between a first image acquisition of an object (which may be any kind of object and is not limited to a target region within a patient), and a second image acquisition of the object. In one embodiment, the images for which non-rigid image registration is performed are discretized images each characterized by an array of pixels, each pixel having an associated pixel value representative of the intensity of the image at a surface unit area corresponding to the pixel. As a first step, 2D DRRs (digitally reconstructed radiographs) may be generated from pre-operative 3D scan data, in step 102. An improved DRR generation process can be implemented in step 102 to bring out the skeletal structures, which are usually not easily visible in the images, or even may be hidden. In step 102, the CT scan data are modified based on a non-linear attenuation model that emphasizes the skeletal structures and thus improves the quality of the DRRs. In the image enhancement technique, implemented for the DRRs in step 103 in flowchart 100, a top-hat filter is used to bring out the skeletal structures in the DRRs generated in step 102. In the illustrated embodiment, image registration is performed in a selected region of interest (ROI) within the enhanced DRR, in order to improve efficiency. Accordingly, an ROI is defined in the DRR, in step 104, after enhancement of the DRRs. An ROI selection process is performed that is based on image entropy, is fully automatic, and does not require user interaction. Intra-operative 2D x-ray projection images are then generated, in near real time, in step 110. Image enhancement is performed on the x-ray images, in step 115, using a top-hat filter as in step 103. Non-rigid image registration is then performed between the enhanced x-ray images and the enhanced DRRs, within the ROI. In particular, a similarity measure is used to compare the pixel intensities in the x-ray images and the DRR images, in order to determine any change in the position and/or orientation and/or physiological deformation of the patient. In steps 120-150, a non-rigid deformation that describes real patient movement and body deformation is defined. To define the non-rigid deformation, a full motion field is constructed that is composed of many local motion fields, i.e. a plurality of locally estimated motion vectors. To estimate local motion at a given point of interest within the ROI, a similarity measure based on pattern intensity is used to compare pixel intensities. A full motion field that is composed of many local motions can describe any desired non-rigid deformation. Further, a full motion field derived in this manner can account for non-rigid motions (translations and/or rotations) of the object, in addition to non-rigid deformations, between different image acquisitions of the object. In order to efficiently compute the local motion vectors at any point of interest within the ROI, hierarchical mesh motion estimation and multi-level block matching (performed in conjunction with an intensity-based similarity measure) are performed. These methods allow for a fast computation of the image registration algorithm 100. A smoothness constraint is imposed to reconstruct the motion field at mesh nodes in which mismatching occurred. The non-rigid transformation parameters for the non-rigid image registration are then computed from the full motion field. In the embodiment illustrated in FIG. 2, the non-rigid deformations described by the full motion field occur in between the acquisition of the 3D CT scan data of a treatment target region in a patient, and the acquisition of the x-ray projection images of the target region. In step 120, a global translation of the entire image is first estimated. The estimated global translation is used as the initial estimate for all further local motion estimation. In the next step 130, mesh nodal motion estimation is performed, using a hierarchical mesh structure designed to estimate the local motion in multiple levels. In the next step 140, motion field reconstruction is performed for those mesh nodes in which a mismatch occurs. The reconstruction of the motion field is performed by imposing a smoothness constraint, which is based on the assumption that local motions are continuous, because of matter coherence. In step 150, the local motion vector at any desired point of interest is derived by interpolating from the nodal motions estimated for the mesh nodes that surround the point of interest. The full motion field is then constructed, using the local motion vectors derived for a plurality of desired points of interest. In the final steps, shown as step 155 and step 160 in FIG. 2, the non-rigid transformation parameters are derived from the full motion field. In step 155, the target displacements are derived from the full motion field. In step 160, the average rigid transformation is derived from the full motion field. FIG. 3A schematically illustrates the generation of 2D DRRs from 3D scan data of a treatment target within an anatomical region of a patient, as performed in step 102 in FIG. 2. In the illustrated embodiment, the 3D scan data are CT scan data; alternatively, in other embodiments other types of 3D scan data that are known, e.g. MRI (magnetic resonance imaging) scan data, PET (positron emission tomography) scan data, or ultrasound scan data, may be used. In FIG. 3A, the volumetric 3D CT image of the target is schematically referred to using reference numeral 60. The DRRs 65A and 65B, shown in FIG. 3A, are artificial, synthesized 2D images that represent the radiographic image of the target that would be obtained if imaging beams, having the same intensity, position and angle as the beams used to generate the real time x-ray projection images, were transmitted through the target, and if the target were positioned in accordance with the 3D CT scan data. The reference numerals 50A and 50B illustrate the hypothetical positions and angles from which the imaging beams would be directed through a target positioned in accordance with the CT volumetric image 60 of the target. As known, CT scans can generate a 3D image of the target object, one axial slice at a time. Each axial CT slice can be viewed as being composed of a plurality of individual volume elements, called CT voxels. Each CT voxel is thus disposed within one of a plurality of axial voxel slices, each voxel slice representing a corresponding axial slice of the target object. Each CT voxel is characterized by a numerical value, called the CT number, which represents the x-ray attenuation characteristics of the corresponding CT voxel. A CT image of a target object can be viewed as a map or distribution within the object of a 3D array of CT numbers. The reconstruction of a CT image thus requires an accurate measurement of the x-ray attenuations, and an accurate determination of CT numbers. Typically, DRRs are generated by casting hypothetical beams or rays through the CT volumetric image of the target. Each ray goes through a number of voxels of the 3D CT image 60. By integrating the CT numbers for these voxels along each ray, and projecting onto an imaging plane (shown as 70A and 70B, respectively, in FIG. 3A), the resultant image would emulate the radiograph that would be obtained by passing rays from hypothetical locations (50A and 50B, respectively) through a target positioned in accordance with the-volumetric 3D image 60. The sum of CT numbers is performed from the source point of the hypothetical ray, onto a plane orthogonal to the central axis of the hypothetical beam. The sum is performed along each ray, an interpolated value being contributed by each voxel through which the ray passes. Each voxel contribution is interpolated over orthogonal segments along the beam path. Various known ray tracing algorithms may be used when generating DRRs. Applications such as image-guided radiosurgery require that the comparison between the DRRs and the real-time x-ray images, as well as the subsequent adjustment of the position of the x-ray source, be made very rapidly and accurately. In practice, the accuracy should be below 1 mm, and the computation time should be on the order of a few seconds. Unfortunately, it is difficult to meet both requirements simultaneously. For example, the two different modality images, i.e. CT scan images and x-ray images, have different spatial resolution and image quality. Generally, x-ray image resolution and quality are superior to the resolution and quality of DRR images, which are only synthesized images. Typically, some structures in the DRR may appear more blurred (especially normal to the CT slice plane), compared to the x-ray image. Ideally, an optimal similarity measure for a 2D/3D registration process should allow for an accurate registration to be achieved, despite such differences. Also, DRR generation relies on a proper attenuation model. Because attenuation is proportional to the mass intensity of the target volume through which the beam passes, the exact relationship between the traversed mass intensity and the CT image intensity needs to be known, in order to obtain an accurate modeling. Establishing this relationship is difficult, however, so the linear attenuation model is often used, in conventional methods and systems for DRR generation. As is known, the linear attenuation coefficient of a material is dependent on x-ray energy. CT machines and x-ray machines work at different effective energies, however. As a result, the attenuation coefficients measured by a CT scanner are different from the attenuation of a beam of x-rays passing through the target. The skeletal structures in DRR images cannot be reconstructed very well using the linear model, the DRRs being only synthetic x-ray projection images. At the CT scan x-ray energies, the ratio of bone-to-soft-tissue attenuation is much lower than at the x-ray radiographic projection energies. Thus, in a DRR produced from a 3D CT volume, the image contrast from soft tissue tends to be comparable with the image contrast from bone, reducing the clarity of bone details, for example. The quality of DRR images relies on proper attenuation modeling, as well as a proper interpolation scheme for interpolation the CT numbers. In one embodiment, an improved DRR generation is accomplished during step 102 (as shown in FIG. 2), by formulating an improved x-ray attenuation model for fiducial-less tracking, so that the DRRs become more like the real x-ray projection images. A linear attenuation model is no longer assumed, and the CT numbers are modified in order to compensate for the above-mentioned a difference in the bone-to-tissue attenuation ratio. On the basis of many experiments conducted with patient clinical data, the following empirical equation was formulated to modify the original CT numbers: C(x,y,z)=a C0(x,y,z) ebCo(x,y,z) (1) where C(x,y,z) represents the modified CT number of a 3D CT voxel located at a point (x,y,z); a and b represent weighting coefficients; and C0(x,y,z) represents the un-modified CT number, based on a linear attenuation model, of a 3D CT voxel having a location (x,y,z). FIG. 3B provides a schematic plot of equation (1). In FIG. 3B, the curve identified by reference numeral 270 represents CT numbers resulting from the non-linear attenuation model provided by the empirical formula (1), whereas the curve identified by reference numeral 280 represents CT numbers resulting from a linear attenuation model. After modification of the CT numbers using equation (1), skeletal structures in the images are emphasized, and soft tissues are suppressed. In other words, use of the empirical formula (1) to process CT numbers during DRR generation serves to bring out the skeletal features against the tissue background, in the DRRs. In the region identified in FIG. 3B with reference numeral 290, the details of the rigid structures (e.g. skeletal structures) are more easily visible using the non-linear attenuation curve 290, since the details are spread over a broader range of intensity values, as compared to the linear attenuation curve 280. Empirically, the weighting coefficient b in equation (1) is 128 for 8-bit images, whereas the weighting coefficient a is slightly different for the cervical, thoracic and lumbar cases, respectively. The interpolation scheme used in one embodiment to improve the quality of DRRs is bi-linear interpolation. In this embodiment, bi-linear interpolation is performed in step 210, to integrate the CT numbers along the CT voxels that are encountered by each cast ray. In one embodiment, the bi-linear interpolation is followed by a 1-D polynomial interpolation over three voxel slices, for each voxel of interest. The three voxel slices include the voxel slice containing the voxel of interest, plus each adjacent voxel slice. Fiducial-less tracking relies on skeletal reference structures that are usually not easily visible, or may even be hidden in the DRRs and in the x-ray projection images. Because fiducial-less tracking is based on registration of such skeletal structures, both the DRR and the x-ray images have to be enhanced to bring out the details of the vertebral structures and improve their visibility. In one embodiment, therefore, image enhancement is undertaken for both the DRRs and the x-ray projection images. In most thoracic and lumbar cases, the skeletal structures are not easily visible or even hidden in DRR and X-ray images. For these cases therefore, enhancement of the DRR and the x-ray images is necessary, in order to make registration at all possible. In cervical cases, the skeletal structures of spine are well visible in both the DRR and the x-ray images, but the details of the structures are still not clear. Accordingly, in cervical cases, the DRR and the x-ray images should be enhanced to improve the registration. FIG. 4 illustrates exemplary images that have been enhanced to increase the visibility of skeletal structures, using top hat filtering. In the embodiment illustrated in FIG. 4, a top-hat filter was designed and used to enhance the x-ray images (step 115 in FIG. 2) and to enhance the DRR images (step 103 in FIG. 2). In particular, the skeletal structures in the images have been enhanced, i.e., brought out, by applying a top hat filter operator to the pixels of the x-ray projection images and the DRR images. As known, a top hat filter is a nonlinear operator that finds the brightest pixels in two different size neighborhoods, then keeps the extreme values. In one embodiment, the top hat filter operates as follows: if the brightest value in the smaller neighborhood region is greater that the value in the larger neighborhood, by an amount determined by a user-entered threshold, then the pixel remains, otherwise it is eliminated. As a result of applying a top hat filter to the images, it is possible to locate features of interest. In one embodiment, the top-hat filter is designed by using a weighted combination of image opening and closing with a certain structural element. The top hat filter operator is defined mathematically as follows: f e = f + w × [ f - γ B ( f ) ] - b × [ ϕ B ( f ) - f ] = f + w × WTH ( f ) - b × BTH ( f ) ( 2 ) where fe represents the enhanced image, resulting from the application of the top hat filter operator to each pixel in the original image; f represents the original image; w and b represent weighting coefficients, yB(f) represents a structural element for the opening of the original image f, and φB(f) represents a structural element for the closing of the original image f. In expression (2) above, WTH(f)=f−yB(f) is called a white top-hat filter, whereas BTH(f)=φB(f)−f is called a black top-hat filter. The structural elements yB(f) and gB(f) are masks that are used to perform the basic morphological operation. The sizes of the structural elements vary slightly for cervical, thoracic, and lumbar applications. The empirical values are determined experimentally. The weighting coefficients w and b are determined adaptively by the amplitudes of WTH(f) and BTH(f), respectively. Empirically, the values of the weighting coefficients w and b have been found to be about 1 each (w=1, b=1), for a cervical case in which less tissue is present. In the lumbar case, in which more tissue is present, the values of w and b have been found to be greater than about 2 each (w>2, b>2). In the lumbar case, the weighting process brings out the skeletal structures to a greater degree, compared with the cervical case. In one embodiment, image registration is conducted only in a certain region of interest (ROI) defined in the DRR. The ROI contains the treatment target (e.g. a tumor or lesion). In one embodiment, image entropy is specifically defined, in step 104 in FIG. 2. In this way, the ROI can be automatically selected, for optimum registration, minimizing or even eliminating user interaction. Because image registration relies on the image content or image information, in this embodiment the ROI is optimized to contain as much information as possible. The Shannon entropy, known from conventional communication theory, is commonly used as a measure of information in signal and image processing. It is defined as H=−Σn pi log pi, where H represents the average information supplied by a set of n symbols whose probabilities are given by p1, p2, . . . , pn. When applied to the pixels of each image (as enhanced in steps 103 or 115 in FIG. 2), the Shannon entropy for each image is defined by: H=−Σp(I) log p(I), where I is the image intensity level, and p(I) is the probability of an image intensity value I occurring within the ROI. In the original formulation by Shannon, any change in the data that tends to equalize the probabilities p1, p2, . . . , pn increases the entropy, as observed by Shannon. For a given image, the Shannon entropy is conventionally calculated from a image intensity histogram, in which the probabilities p1, p2, . . . , pn are histogram entries. In one embodiment, the Shannon entropy H is modified, based on the fact that the skeletal structures occur in bright areas. In this embodiment, a modified Shannon entropy is used for each image, which is defined as follows: H=−ΣI p(I)log p(I), (3) where again I is the image intensity level, and p(I) is the probability of the image intensity value I occurring within the ROI. In step 104 (shown in FIG. 2), the modified Shannon entropy is first determined for the enhanced DRR image. Once the modified Shannon entropy H is calculated, an ROI is then automatically selected by determining the region within the DRR for which the entropy H is maximized. Subsequent steps in the image registration process (steps 120-150 in FIG. 2) take place only within the ROI. Restricting the image registration process to within a ROI has several advantages. One advantage is that such a restriction can speed up the registration process, since the registration needs to be performed only for the ROI. For example, the similarity measure needs only be computed for the ROI, and block matching need only be performed within the ROI. Further, the registration process is more accurate when limited to an area within the ROI. The more limited the region in which registration is conducted, the less likely it is that structures within the ROI would have moved relative to each other between the time of the pre-operative CT scans and the time of the medical treatment. Based on the improved and enhanced DRRs (step 103 in FIG. 2), and the enhanced x-ray projection images (step 115 in FIG. 2), in which the skeletal reference structures have been brought out to make fiducial-less tracking possible, a non-rigid deformation of the anatomical region is determined in steps 120-150 (shown in FIG. 2). In this patent, a ‘rigid body’ assumption, i.e. which is often made in image registration applications, and which assumes that between image acquisitions, the anatomical and pathological structures of interest do not deform or distort, is not made. There is no longer a need to preserve the ‘rigid body’ constraints, i.e. to require that the body be rigid and not undergo any local variations during the transformation. Based on an abundance of observations and analyses on clinical patient data, in the present patent a non-rigid deformation is assumed, in lieu of a rigid transformation, to obtain an improved description of the real patient movement and body deformation. By computing a non-rigid deformation field, patient position/orientation can be more reliably monitored corrected during the initial alignment, as well as throughout the entire treatment. A non-rigid image registration allows the inherent local anatomical variations that exist between different image acquisitions to be accounted for, in contrast to a rigid image registration which does not allow the overcoming of such variations. Non-rigid registration defines a deformation field that provides a translation or mapping for every pixel in the image. In one embodiment, a full motion field, composed of many local motion vectors or fields, is computed in order to derive the non-rigid deformation field. In order to estimate local motion fields, in one embodiment, a multi-level block matching method is used in conjunction with a similarity measure based on pattern intensity. This approach allows the local motion to be rapidly and accurately estimated in most parts of the ROI. Multi-level block matching, which allows for computational efficiency, is described in conjunction with a rigid registration algorithm, in a commonly owned application, U.S. Ser. No. 10/652,786 (the “'786 application”), incorporated by reference in its entirety. A similarity measure based on pattern intensity, used in conjunction with a registration algorithm based on rigid transformations, i.e. the “FAST 6D algorithm” developed by Accuray, Inc. for use with the Cyberknife radiosurgery system, is described in full in commonly owned applications, U.S. Ser. No. 10/652786 (the “'786 application”), U.S. Ser. No. 10/652717 (the “'717 application”), and U.S. Ser. No. 10/652785 (the “'785 application”), which are all incorporated by reference in their entireties. In the present patent, the pattern intensity based similarity measure and the multi-level block matching method are used in conjunction with a registration algorithm based on a non-rigid (rather than a rigid) transformation. The pattern intensity-based similarity measure, originally developed for a rigid image registration algorithm, provides a powerful and efficient technique for solving the 2D/3D image registration problem, also in a non-rigid framework. In one embodiment, block matching is performed, i.e. a small block centered around a point of interest is used in order to locally estimate the displacements at each desired point within the ROI. As known, when using block matching to register a first image onto a second image, the first image is divided into different blocks, typically rectangular boxes of equal size. Each point of interest, which may be a mesh node, or may be a non-node pixel that is surrounded by mesh nodes, is taken as the center of one of the blocks. These blocks are then translated so as to maximize a local similarity criterion, which in one embodiment is the pattern intensity based similarity measure, described above. In block matching methods, it is generally assumed that each pixel in a block has the same motion, and a block matching algorithm is typically used to estimate the motion vectors for each block. In a block matching algorithm used in one embodiment, a search is conducted for a matching block in the second image, in a manner so as to maximize a measure of similarity, based on pattern intensity, between the respective blocks. The search is for a location of the maximum in the similarity measure function, the maximum representing the existence of a matching block in the second image. The search may be conducted within a search window that is defined around the point of interest and that contains the block. In any block matching algorithm, it is important to optimize the search strategy, and to select an appropriate block size. For small blocks, the translational rigid model is typically assumed. Even though rigid rotations or some other complicated deformations exist, the rigid body translation model is valid for estimating the translations for the block center point. When rotations or other deformations exist in addition to the translations, the accuracy increases with decreasing block size, and decreases with increasing block size. With the use of smaller block sizes, however, the possibility of mismatching increases. In one embodiment, a block size selection strategy is adopted in which it is assumed that larger blocks are needed for larger displacements, and that smaller blocks are need for smaller displacements. FIGS. 5A and 5B schematically illustrate local motion estimation for a point of interest within a target in a patient, using block matching. In the embodiment illustrated in FIG. 5A, the target is located in the cervical region of the spine, whereas in the embodiment illustrated in FIG. 5B, the target is located in the thoracic region. In both FIGS. 5A and 5B, the left and the right pictures are the DRR and X-ray images, respectively. In each figure, a small block 203A is defined around a point of interest 205 in the DRR. Also, a search window 207 that encompasses the block 203 is defined in the DRR. The matching block in the x-ray image is indicated in the figures with reference numeral 203B. In the embodiment illustrated in FIGS. 5A and 5B, the size of the search window 207 is 48 mm×48 mm, and the block size is 15×15 mm. It can be seen, simply by visual inspection, that the point of interest 205 is well located in the X-ray image. FIG. 6 schematically illustrates a multi-resolution image representation, when implementing multi-level block matching, using multiple candidates. Multi-level block matching is a fast search method that uses the displacement estimates made at a lower level as the initial results for subsequent search phases. The basic idea in multi-level block matching is to match the images at each of a plurality of resolution levels, successively, starting from the lowest resolution level and moving up to the highest resolution level. The full-size image, having the highest resolution level, is shown at the bottom in FIG. 6, as level 1. The upper images (level 2 and level 3) have successively lower spatial resolutions, the image having the lowest resolution being shown as level 3. The lower resolution images are obtained by lower pass filtering, and sub-sampling the full-size images. In FIG. 6, assuming that the full image block size is W×H in Level 1, the block sizes are W 2 × H 2 and W 4 × H 4 in Level 2 and Level 3, respectively, as indicated in the figure. In the lowest resolution level (Level 3), a large search range is used to enable estimation of large displacements. A very small search range (−2, +2) is used in the rest of the resolution levels. The results at the lower resolution level serve to determine rough estimates of the displacements. The output at the lower level is then passed onto the subsequent higher resolution level. The estimated motion vector (in most cases, a translation vector) for the block is successively refined, using the higher resolution images. In the final matching results, the accuracy of the estimated translations depends on the spatial resolution of the highest resolution images (shown as level 1 in FIG. 6). There is some risk in multi-level matching. It is possible that the estimate at lower levels may fall in a local maximum, and far away from the global maximum that is being sought. In this case, further matchings at subsequent higher resolution levels may not converge to its global maximum. To overcome this risk, multiple candidates are used for the estimates, in one embodiment. Many candidates that have shown optimal matching results are passed on from the lower levels to the higher resolution levels. The more candidates that are used, the more reliable are the estimates. In one embodiment, the best candidates are ranked by the similarity measure function values. In one embodiment, a similarity measure based on pattern intensity is used, in conjunction with multi-level block matching. As mentioned earlier, this similarity measure is a key element contributing to the success of the “FAST 6D algorithm,” described in the commonly owned '786 application, '717 application, and '785 application. In one embodiment, the similarity measure is determined by forming a difference image between the “live” (or near real time) x-ray projection images and the DRR images, and applying upon each pixel of the difference image a pattern intensity function. Specifically, the difference image Idiff(i,j) is formed by subtracting a corresponding pixel value of the pre-operative DRR image from each pixel value of the intra-operative x-ray projection image, within the ROI: Idiff(i, j)=ILive(i, j)−IDRR(i, j) (4) In equation (4), I(i,j) represents the image intensity value of a pixel located at the i-th row and j-th column of each pixel array for the respective image. Specifically, Idiff(i, j) represents an array of pixel values for a difference image formed by subtracting the corresponding pixel values of the second image from each pixel value of the first image. Ilive(i,j) represents the (i,j)-th pixel value of the first image of the object. IDRR(i,j) represents the (i,j)-th pixel value of the second image of the object. The similarity measure operates on this difference image, and is expressed as the summation of asymptotic functions of the gradients of the difference image over the pixels within a neighborhood R: ∑ i , j ∑ k , l ⋐ R σ 2 σ 2 + ( I diff ( i , j ) - I diff ( i + k , j + l ) ) 2 ( 5 ) In equation (5) above, the constant σ is a weighting coefficient for the pattern intensity function. The sensitivity of the solution to the variation of x-ray image can be minimized by careful selection of this constant. The larger the weighting coefficient, the more stable the results. However, the choice of σ entails a tradeoff between stability and accuracy. When the value of σ is too large, some small details in the images cannot be reflected in the similarity measure. Based on the experiments, the empirical value for σ is in the range from about 4 to about 16, in one embodiment. FIG. 7 schematically illustrates a neighborhood R for calculating a similarity measure based on pattern intensity. As seen from FIG. 7, the neighborhood R in the illustrated embodiment is defined so that the gradients of the difference image can be considered in at least four directions (horizontal, vertical, 45° diagonal and −45° diagonal). When the neighborhood R is defined in this manner, equation (5) for the similarity measure becomes: ∑ i , j σ 2 σ 2 + ( ( I diff ( i , j ) - I diff ( i , j - 1 ) ) 2 + ∑ i , j σ 2 σ 2 + ( ( I diff ( i , j ) - I diff ( i - 1 , j ) ) 2 + ∑ i , j σ 2 σ 2 + ( ( I diff ( i , j ) - I diff ( i - 1 , j - 1 ) ) 2 + ∑ i , j σ 2 σ 2 + ( ( I diff ( i , j ) - I diff ( i - 1 , j + 1 ) ) 2 . ( 6 ) Equations (5) and (6) for pattern intensity have several advantages. First, the difference image filters out the low frequency part that predominantly consists of the soft tissues, and keeps the high frequency part that predominantly consists of the skeletal structures. This feature makes the algorithm robust to some brightness intensity difference between live and DRR images. Second, because of the asymptotic function, the measure is less affected by the pixels whose intensity value slightly deviates from its neighboring pixels. These types of pixels are thought to contain random noise. Third, because the asymptotic function quickly approaches to zero when the variable increases, large intensity differences such as image artifacts have the same effects on the similarity measure regardless of their magnitude. Due to this feature, the pattern intensity is less sensitive to image artifacts. FIGS. 8A-8B provides a plot of the similarity measure function that was used for the local motion estimation illustrated in FIGS. 5A-5B, and that is based on equations (5) and (6). The similarity measure function is plotted with respect to translations in two mutually orthogonal directions (x- and y-). The existence of the global maximum is clearly shown, in both FIG. 8A and FIG. 8B. Several local maximum points also exist in FIGS. 8A and 8B, however. This indicates that the use of multiple candidates may be necessary in multi-level block matching, as explained above. The estimation of local motion fields using block matching together with hierarchical mesh motion estimation, as well as the reconstruction of the full motion field from the plurality of locally estimated motion fields, are performed in steps 120-150 of the flowchart shown in FIG. 2. Fast generation of the full motion field is achieved by using hierarchical mesh tracking, and using SIMD (single instruction multiple data) technology to perform image computation in parallel. In one embodiment, a global translation of the entire image (measured as a translation of the image center of the image) is first estimated, then used as the initial estimates for all further local motion estimation. In other words, a rough estimate is made of the center displacement for the entire image, and is used as the starting estimate for all local displacements. Referring back to FIG. 2, the first step (indicated with reference numeral 120 in FIG. 2) in generating a full motion field for a target, between the pre-operative scan and the intra-operative treatment, is the step of estimating a global translation for the entire image, or equivalently, estimating the center displacement of the image. FIG. 9 illustrates the estimation of global motion (in this case, translation only), between the image center of a DRR and the image center of a corresponding x-ray image. In the illustrated embodiment, the image center is used as the block center. The step of global translation estimation is very important, because any failure during this step will affect the rest of the local motion estimation process. To prevent any possibility of mismatching, a very large image block is used in the illustrated embodiment. The maximum tracking range can be calculated as the difference between the block size and the entire image size. For example, if the matching size is 80×80 mm, the maximum tracked translation is 60 mm. In the embodiment illustrated in FIG. 9, a block having a size of 160×160 pixels (64 mm×64 mm) is used. The search window in the illustrated embodiment is the entire image. The maximum track range for the illustrated embodiment is (−50 mm, +50 mm). After global motion estimation, the next step 130 (see FIG. 2) is mesh motion estimation. In this step, a hierarchical 2D mesh structure is designed in order to estimate local motion in multiple levels. As known, a 2D mesh (or a 2D mesh grid) refers to a tesselation of a 2D region into polygonal patches or elements, whose vertices are called mesh nodes. Unlike block matching algorithms, which generally assume only translational motion, 2D mesh models allow for spatial transformations to model rotations, scalings, and deformations of the object that was imaged, in addition to translations of the object. Compared to block matching algorithms, therefore, mesh-based methods may produce a more accurate representation of the motion field, for example may generate continuously varying motion fields. FIG. 10A schematically illustrates a mesh grid 200 established for a DRR of a target region, and a corresponding mesh grid 202 established for an x-ray image of the target region, in an embodiment in which the target is located within the cervical region of the spine. FIG. 10B schematically illustrates a mesh grid 204 established for a DRR of a target region, and a corresponding mesh grid 206 established for an x-ray image of the target region, in an embodiment in which the target is located within the thoracic region of the spine. FIG. 10C schematically illustrates a mesh grid 208 established for a DRR of a target region, and a corresponding mesh grid 210 established for an x-ray image of the target region, in an embodiment in which the target is located within the lumbar region of the spine. With a 2D mesh, motion compensation within each mesh element or patch may be accomplished by deriving a spatial transformation between the images, where the transformation parameters are computed from the nodal motion vectors, i.e. from the motion vectors that are estimated for the mesh nodes that are located at the vertices of the mesh. In other words, mesh-based motion estimation consists of finding a spatial transformation that best maps one set of mesh elements in a first image acquisition onto another set of mesh elements in a second image acquisition. In particular, mesh motion estimation consists of finding the vertices of corresponding mesh elements in the other image, i.e. finding the corresponding mesh nodes in the other image, such that errors are minimized in the overall motion field. Typically, a number of mesh nodes are selected in one image, and the corresponding mesh nodes in the other image are estimated. For any pixel located within a mesh element (as opposed to being located on the vertices of the mesh elements), the mapping between different image acquisitions is performed through interpolation. The local motion vectors for such pixels are estimated by interpolating from the nodal motion vectors that were estimated for the mesh nodes that surround the pixel. In one embodiment, hierarchical mesh motion estimation may be performed. By hierarchical mesh motion estimation, it is meant that nodal motion is estimated for the mesh nodes that define the mesh structure, for each of a plurality of mesh resolution levels. Motion estimation performed with a course mesh provides the initialization for the subsequent (finer) resolution levels of the mesh. To estimate the motion of each mesh node, multi-level block matching may be performed. FIG. 11 illustrates a mesh hierarchy, during mesh motion estimation. As seen from FIG. 11, the mesh hierarchy starts from a relatively course mesh, 220, and progresses onto finer meshes, illustrated as 222 and 224. Using the global translations (estimated in step 120 as the initial estimates), nodal motion for the mesh nodes located at the vertices of the most course mesh is first calculated. These estimates are then passed onto the subsequent, finer mesh. At each level, nodal motion is updated, using a smaller search range. Finally, the motion vectors for the mesh nodes at the final one of the mesh resolution levels (characterized by the finest mesh resolution level) are refined. For all the nodes, multi-level block matching with multiple candidates is used, together with the pattern-intensity based similarity measure, given in equations (5) and (6). FIG. 12 schematically illustrates the passing on of node estimation, from a course mesh resolution level onto a finer mesh resolution level. At each mesh resolution level after the first level, the mesh nodes include both 1) mesh nodes generated at a previous mesh resolution level; and 2) mesh nodes that are newly added at the current mesh resolution level. In the illustrated embodiment, the initial estimates for nodal motion vectors, for the newly added nodes at the current mesh, are obtained by linear interpolation of the existing nodal motion vectors, at the previous mesh resolution level. During this process, any unreliable mesh node needs to be detected, so that only reliable nodes are passed onto the subsequent mesh level. FIG. 12 illustrates how such a detection can be performed, using a mesh node referred to in FIG. 12 as ‘node 5.’ In the illustrated embodiment, the difference between the motion vector (in this case, translation vector) of node 5, and the median motions (translations) computed from its 9 surrounding nodes (nodes 1-4, 6-9 in FIG. 12) is taken. As seen from FIG. 12, the translation of node 2 is the average of the translations of node 1 and node 3; the translation of node 4 is the average of the translations of node 1 and node 7; the translation of node 6 is the average of the translations of node 3 and node 9; and the translation of node 8 is the average of the translations of node 7 and node 9. The translation of node 5 is the average of the translations of nodes 1, 3, 7, and 9. If the difference between the translation of node 5 and the median translations computed from its 9 neighboring nodes is less than a predefined threshold, the node 5 is considered as a reliable node. Otherwise, it is considered as an unreliable node, and its translations are replaced with the median values and passed to the subsequent mesh. For most mesh nodes, the estimates of motion are reliable and accurate. For a few nodes where mismatching may occur and the estimation may not be reliable, the displacements need to be reconstructed by the surrounding node displacements. Accordingly, the next step in the registration algorithm flow chart in FIG. 2 is step 140 of motion field reconstruction, during which the motion field is reconstructed from surrounding nodes, for those nodes in which mismatching occurs. The inaccurate nodal motion vectors can be detected by using 3×3 median filtering. Local motion estimation relies on the local image content. In some smooth local regions, mismatching may occur. During mesh motion estimation, the estimation in most nodes is pretty accurate. For a few nodes where mismatching occurs, the motions should be reconstructed from their surrounding nodes. What is known a priori is matter coherence of bone and tissue, and accordingly, the smoothness of local motion. In other words, the estimated local motion vectors are thought to be smooth and continuous, because of matter coherence. By imposing this physically-based smoothness constraint, a cost function is formulated to reconstruct the motion field. In one embodiment, the cost function is expressed mathematically as follows: E(d)=∫∫β(d−u)2dxdy+λ∫∫(d,x2+d,y2)dxdy (7) In equation (7) above, E(d) represents the cost function, d represents a desired local estimate for a nodal motion vector at coordinates (x,y), u represents a locally estimated nodal motion vector at coordinates (x,y), and β represents a reliability constant that ranges from 0 to 1, where β=0 indicates an unreliable estimation, and β=1 indicates a reliable estimation. By performing a finite difference of the derivatives over the mesh grids, a discretized form for the cost function in equation (7) is expressed as: E(di,j)=ΣΣβi,j(di,j−ui,j)2+λΣΣ[(di,j−di,j)2+(di,j−di,j−1)2] (8) where ui,j represents the locally estimated translations, di,j is the local motion desired, βi,j=1 if the estimation is reliable and βi,j=0 if the estimation is unreliable. The first term on the right side of equation (8) reflects the fidelity to the observed data in the reconstruction. The second term imposes the smoothness constraints on the motion field in two spatial directions. The minimization of the cost function given by equation (8) results in a system of simultaneous linear equations δ E ( d i , j ) ∂ d i , j = ( β i , j + 4 λ ) d i , j - λ ( d i - 1 , j + d i + 1 , j + d i , j - 1 + d i , j + 1 ) - β i , j u i , j = 0 ( 9 ) In one embodiment, the iterative algorithm of successive-over relaxation (SOR), which is fast and convergent, is used to solve the equations: di,j(n+1)=di,j(n)−ω[(βi,j+4λ)di−1,j(n)−λ(di−1,j(n)+di+1,j(n)+i,j−1(n)+di,j+1(n))−βi,jui,j]/(βi,j+4λ) (10) Once all the nodal motion vectors have been estimated at all the mesh nodes, the translations for any point (or pixel) inside the ROI can be computed by interpolation. FIG. 13 schematically illustrates the determination of a motion vector for a point of interest, by interpolation from surrounding nodes. In the illustrated embodiment, quadratic interpolation is performed, using the 9 nearest nodes, and 9 shape functions are used. Assuming the motion vector (dx(i),dy(i)) for nine nodes, the motion vector (dx,dy) at the point of interest is computed using the following expressions: dx = ∑ i = 1 9 N ( i ) dx ( i ) , dy = ∑ i = 1 9 N ( i ) dy ( i ) , ( 11 ) where N(i) is the shape function for the node (i), and where N(i) for I=1, 2, . . . 9 are given as follows: N(1)=(1−ξ)(1−η)/4−(N8+N5)/2, N(2)=(1−ξ)(1−η)/4−(N5+N6)/2, N(3)=(1+ξ)(1+η)/4−(N6+N7)/2, N(4)=(1−ξ)(1+η)/4−(N7+N8)/2, N(5)=(1−ξ2)(1−η)/2, N(6)=(1−ξ)(1−ηhu 2)/2, N(7)=(1−ξ2)(1+η)/2, N(8)=(1−ξ)(1−η2)/2, N(9)=(1−ξ2)(1−η2) (12) Using steps 120, 130, and 140, described above, the local motion vectors can be estimated for a plurality of points of interest within the ROI. The full motion field is obtained as a composite or superposition of all of the local motion vectors that are estimated for the many points of interest that have been selected for motion estimation. FIG. 14A schematically illustrates, in vectorial form, a full motion field (reconstructed from many estimated local motion vectors), in an embodiment in which the target is located within the cervical region of the spine. FIG. 14B schematically illustrates, in vectorial form, a full motion field (reconstructed from many estimated local motion vectors), in an embodiment in which the target is located within the thoracic region of the spine. FIG. 14C schematically illustrates, in vectorial form, a full motion field (reconstructed from many estimated local motion vectors), in an embodiment in which the target is located within the lumbar region of the spine. The final step in the image registration process is target localization, namely deriving the target translations and rotations from the full motion field that has been determined. In one embodiment, non-rigid image registration seeks to determine a projection mapping or transformation between different coordinate systems in respective image acquisitions such that points in each space which correspond to the same anatomical point are mapped to each other. In one embodiment, the transformation is represented by a set of non-rigid transformation parameters (dxT, dyT, dzT, r, p, w), where (dxT, dyT, dzT) represent the translations of the target, and (r, p, w) represent rotations of the target. Referring back to FIG. 2, the 3-D target translation (dxT,dyT,dzT) can easily be obtained in step 155 (shown in FIG. 1), given the 2D local motion fields (dxA, dyA) for projection A, and (dxB, dyB) for projection B, using the following expressions: dxT=(dxTA+dxTB)/2, dyT=(dyTA−dyTB)/√{square root over (2)}, dzT=(dyTA+dyTB)/√{square root over (2)} (13) The global rigid rotations (r, p, w) can be calculated from the motion fields (dxA, dyA) in projection A and (dxB, dyB) in projection B. Using the target as the rotation center, global rigid rotations are useful for position and rotation correction and compensation during initial patient alignment and treatment. Because the target translation is already calculated, the calculation of the global translation is not needed. To get the three rotations in 3D patient coordinates, three 2D in-plane rotations are first computed, including the in-plane rotations θA and θB in projections A and B, respectively, and the in-plane rotation θx in a plane perpendicular to the inferior-superior axis. Approximately, the global rotations can be expressed as: r=θx, p=(θB−θA)/√{square root over (2)}, w=(θB+θA)/√{square root over (2)}, (14) Estimation of θA and θB is directly based the 2D motion fields in projections A and B, respectively. To estimate θx, a plane is first defined, which passes the target point and is perpendicular to the axis x in the 3D patient coordinate system. Then the motion field is calculated from the two motion fields (xA,yA) and (xB,yB) in projections A and B, respectively. Assuming (dx, dy) is the motion field in the corresponding coordinate (x, y) and θ is the global rotation. When the rotation is small (<10°), the following transformation equation is valid: { dx dy } = [ 0 - θ θ 0 ] { x y } ( 15 ) Given (dx,dy) and (x,y) in many points, θ can be easily calculated using least square minimization method θ = ∑ i ( x ( i ) dy ( i ) - y ( i ) dx ( i ) ) ∑ i ( x ( i ) x ( i ) + y ( i ) y ( i ) ) ( 16 ) Using equations (14) and (16) above, the average rigid transformation parameters can be obtained, in step 160 illustrated in FIG. 2. FIG. 15 is a schematic block diagram of an apparatus 300 for generating a motion field during non-rigid image registration of an object, in accordance with one embodiment. The apparatus 300 can generate, for example, a full motion field of a target region of a patient's anatomy (for example, the spine), between the acquisition of pre-operative 3D scan data of the target region and the acquisition of intra-operative x-ray projection images of the target region. The full motion field, composed of many local motion vectors, can take into account non-rigid deformations of the target region, as well as non-rigid translations and rotations. In this embodiment, the 2D/3D registration problem is one of finding the non-rigid transformation parameters that best align the coordinate system of the DRRs (generated from the pre-operative 3D scan data) with that of the intra-operative x-ray projection images. In one embodiment, the apparatus 300 is configured to perform mesh motion estimation, and to perform multi-level block matching at each mesh node. In this embodiment, the apparatus 300 includes: 1) a mesh grid generator 310 configured to generate in the DRRs a mesh grid defined by a plurality of mesh nodes or vertices; 2) a nodal motion estimator 320 configured to estimate at least one nodal motion vector for each mesh node; and 3) a motion field interpolator 330 configured to determine a local motion vector for each of a plurality of points of interest within the DRR, by interpolating from the surrounding mesh nodes, i.e. by interpolating from the nodal motion vectors that have been estimated for the mesh nodes that surround each of the plurality of points of interest. In an embodiment in which the DRR has been cropped so as to include a specific ROI, so that image registration is restricted to an ROI within the DRR, the motion field interpolator 330 determines the local motion vectors for each of a plurality of points of interest within an ROI defined within the DRR. The ROI can be defined so as to maximize image entropy within the ROI, as explained before. In one embodiment, the system 300 performs hierarchical mesh tracking, i.e. mesh nodal motion estimation is performed for the mesh nodes of the mesh structures defined at each of a plurality of mesh resolution levels. Preferably, these mesh resolution levels are successively increasing mesh resolution levels, i.e. the mesh grid at each successive mesh resolution level has a number of mesh nodes that is greater, compared to the number of mesh nodes at each previous mesh resolution level. In this embodiment, the mesh grid generator 310 is configured to repeat, at each of a plurality of mesh resolution levels, the act of generating a mesh grid defined by a plurality of mesh nodes, and the nodal motion estimator 320 is similarly configured to repeat, at each of a plurality of mesh resolution levels, the act of estimating the nodal motion vector for each mesh node. In this embodiment, the motion field interpolator interpolates from nodal motion vectors that have been determined at the final mesh resolution level. In one embodiment, the mesh nodes at each mesh resolution level after the first level include both previously existing nodes, and nodes that are newly added on, at the current level. In this embodiment, the nodal motion estimator 320 is configured to pass on, at each mesh resolution level, one or more nodal motion vectors that have been estimated at the current mesh resolution level, onto a subsequent mesh resolution level. In particular, for the previously existing nodes, the nodal motion estimator 320 uses the nodal motion vectors that were estimated during a previous mesh resolution level, and that were passed onto the current level from the previous level. The nodal motion estimator 320 includes an interpolator 321, which interpolates from the nodal motion vectors estimated for the previously existing nodes, in order to estimate the nodal motion vectors for the newly added nodes. The nodal motion estimator 320 further includes a nodal motion refiner 323. For both previously existing nodes and newly added nodes, the nodal motion refiner 323 refines the nodal motion vector that has been estimated for each node. In one embodiment, the nodal motion refiner 323 refines the nodal motion vector by performing multi-level block matching, using a pattern-intensity based similarity measure. In this embodiment, the nodal motion refiner 323 defines a block centered on each mesh node in the DRR, and searches for a matching mesh node in the x-ray projection image that maximizes a similarity measure between the block in the DRR, and a matching block in the x-ray image that is centered on the matching mesh node. In one embodiment, the similarity measure is given by equations (5) and (6) above. The nodal motion refiner 323 then refines and modifies the nodal motion vector that was estimated for the particular mesh node, until the nodal motion vector describes a mapping of the mesh node onto the matching mesh node. In one embodiment, the nodal motion refiner 323 performs multi-level block matching, i.e. repeats for a plurality of image resolution levels the acts of defining a block centered on the mesh node of interest, searching for the matching mesh node, and refining the nodal motion vector. In one embodiment, the nodal motion refiner 323 defines a search window around the mesh node of interest, and searches within the search window for a maximum in the similarity measure. Because several local maximums may exist, in addition to the desired global maximum, the nodal motion refiner 323 preferably reviews a plurality of candidates when searching for the location of the maximum in the similarity measure. In one embodiment, the nodal motion estimator 320 is configured to estimate a global translation of the DRR, and to use the global translation as an estimate for the nodal motion vector for each mesh node in the first mesh resolution level. The global translation represents a translation of the image center of the DRR. In one embodiment, the apparatus 300 further includes a motion field reconstructor 328. The motion field reconstructor 328 is configured to reconstruct the nodal motion vector for any mesh node at which mismatching occurs, i.e. for which the estimated nodal motion vector is unreliable. The motion field reconstructor 328 reconstructs such unreliable nodal motion vectors by interpolating from the mesh nodes that surround the unreliable mesh node. In this embodiment, the nodal motion estimator 320 computes the difference between the nodal motion vector for a mesh node, and the median nodal motion vector computed from its surrounding 9 nodes. If the difference is less than a predefined threshold, the node is considered as a reliable node, otherwise it is considered as an unreliable node. The nodal motion vector for an unreliable node is replaced with the median values, and passed on to the subsequent mesh. In one embodiment, the motion field reconstructor 328 reconstructs nodal motion vectors for unreliable nodes by imposing a smoothness constraint on the nodal motion vectors estimated by the nodal motion estimator 320. In one embodiment, the motion field reconstructor 328 imposes the smoothness constraint by formulating a cost function given by equation (8) above, and minimizing the cost function by solving the system of linear equations, as expressed in equation (9). In one embodiment, the motion field interpolator 330 interpolates, for any desired point of interest within the ROI of the DRR, the local motion vector for the point of interest by interpolating from the nodal motion vectors estimated for the surrounding mesh nodes, by performing the summation described in equations (6) and (7). The apparatus 300 may include a computer-readable medium having stored therein computer-readable instructions for a processor. These instructions, when read and implemented by the processor, cause the processor to: 1) input and store, for a first image of an object, data representative of a mesh grid having a plurality of mesh nodes, for each of a plurality of mesh resolution levels; 2) estimate, for each mesh node in each mesh resolution level, at least one nodal motion vector that describes a matching of the mesh node onto a corresponding mesh node in a second image; and 3) compute a local motion vector for one or more points of interest in the first image by interpolating from the nodal motion vectors estimated at a final mesh resolution level for the mesh nodes that surround each point of interest. The computer-readable medium may have stored therein further computer-readable instructions for the processor. These further instructions, when read and implemented by the processor, cause the processor to detect any mesh node for which a mismatch occurs between the mesh node (in the first image) and its corresponding mesh node (in the second image), and to reconstruct the nodal motion vector for the detected mesh node by imposing a smoothness constraint. The computer-readable medium may be any medium known in the art, including but not limited to hard disks, floppy diskettes, CD-ROMs, flash memory, and optical storage devices. The computer readable instructions described above may be provided through software that is distributed through the Internet. FIG. 16 is a schematic block diagram of a system 400 for performing fiducial-less non-rigid image registration, in accordance with one embodiment. The image registration system 400 can register at least one near real time 2D image of an anatomical region with previously generated 3D scan data of the anatomical region. The anatomical region includes at least one treatment target and at least one reference structure, typically a skeletal or vertebral structure. The near real time 2D images are generated by detecting imaging beams (e.g. x-ray imaging beams) that have known intensities, and known positions and angles relative to the anatomical region, after the beams have traversed at least a portion of the anatomical region. The system 400 also includes an x-ray imaging system 435 that generates imaging beams having these known intensities and originating from these known positions and angles. The system 400 includes means 405 for providing the 3D scan data of the anatomical region. The 3D scan data may be CT scan data provided by a CT scanner. Alternatively, MRI scan data, provided by an MRI system, may be used. Alternatively, PET scan data, provided by a PET system, may be used. In these different embodiments, the means 305 for providing 3D scan data may include, but is not limited to, a CT scanner, an MRI system, and a PET system, respectively. The system 400 includes a DRR generator 410 configured to generate at least one DRR (digitally reconstructed radiograph) of the anatomical region, using the 3D scan data and the known locations, angles, and intensities of the imaging beams. The system 400 further includes: 1) an ROI selector 420 configured to select an ROI (region of interest) within the DRR, the ROI containing the treatment target and preferably at least one reference structure; 2) an image enhancer 430 configured to enhance the DRRs and the x-ray images by applying a filter operator to the DRR and to the x-ray image; 3) a similarity measure calculator 440 configured to determine a measure of similarity between the DRR and the x-ray image; 4) a motion field generator 450 configured to generate a 3D full motion field by estimating, for each of a plurality of resolution levels, one or more 2D local motion fields within the ROI, using the similarity measure; and 5) a parameter determiner 460 configured to determine a set of non-rigid transformation parameters that represent the difference in the position and orientation of the treatment target as shown in the x-ray image, as compared to the position and orientation of the treatment target as shown in the DRR, from the 3D full motion field. In an embodiment in which CT data are used, the 3D scan data consist of a plurality of CT numbers representing the image intensity of corresponding 3D CT voxels, where each CT voxel represents a corresponding volume element of the anatomical region, and each CT number represents the attenuated intensity of an x-ray CT beam that has been generated at a CT scan energy level and that has traversed the corresponding volume element of the anatomical region. The system 400 further includes a scan data modifier 470, configured to modify the 3D scan data before the 3D scan data are used by the DRR generator 410, so as to compensate for the difference between the ratio of bone-to-tissue attenuation at the CT scan energy level, and the ratio of bone attenuation at the x-ray projection energy level, i.e. at the known intensity level of the imaging beam. The scan data modifier 470 includes a processor for performing on each CT number a mathematical operation derived from a non x-ray attenuation model, where the mathematical operation is given by: C(x,y,z)=i a C0(x,y,z) eb0(x,y,z) In this formula, C(x,y,z) represents the modified CT number of a 3D CT voxel having a location (x,y,z); a and b represent weighting coefficients; and C0(x,y,z) represents the un-modified CT number, based on a linear attenuation model, of a 3D CT voxel having a location (x,y,z). In one embodiment, the DRR generator 410 includes: 1) a ray casting subsystem 412 configured to cast a plurality of hypothetical rays through the 3D CT voxels, at the known intensities and from the known positions and angles; 2) a CT number integrator 414 for integrating along each hypothetical ray the CT numbers corresponding to the CT voxels that are traversed by the hypothetical ray; 3) a projector 416 for projecting the integrated values of the CT numbers onto an imaging plane. In one embodiment, the CT number integrator 414 includes a bi-linear interpolator 416 configured to perform bi-linear interpolation on the voxels encountered by each ray, and a polynomial interpolator 418 configured to perform, for each voxel of interest within a voxel slice, a one-dimensional polynomial interpolation over the voxel of interest and over voxels on each adjacent voxel slice. Bi-linear interpolation, as well as 1-D polynomial interpolation, are well known, and standard software and/or algorithms that are commercially available may be used. In one embodiment, the filter operator applied by the image enhancer 430 is a top-hat filter, configured to select the pixel having the brightest pixel value from each of at least two different neighborhoods within the DRR and the x-ray image, and to eliminate the remaining pixels in the neighborhoods. Mathematically, the top hat filter is defined by equation (2) above. In one embodiment, the ROI selector includes an entropy calculator that calculates a modified Shannon entropy of the DRR. The modified Shannon entropy is given by: H=−ΣI P(I)log P(I), where I is the value of the intensity of the image, at each pixel of the image, and P(I) is the probability of an image intensity value I occurring within the ROI. The ROI selector further includes region selecting processor for selecting the ROI so that the entropy measure H is maximized within the ROI. Calculation of Shannon entropy is well known in signal processing. Also well known is maximizing (or minimizing) an entropy function, for desired purposes. Therefore, standard software and/or algorithms that are commercially available may be used in the ROI selector 420, with only minimal trivial revisions to incorporate the modification indicated in the formula for modified Shannon entropy. In one embodiment, the similarity measure calculator 440 is configured to form a difference image by subtracting a corresponding pixel value of the DRR from each pixel value of the near real time (or “live”) x-ray image, so that the pixel value at the i-th row and j-th column of the array of pixel values for the difference image is given by: Idiff(i, j)=ILive(i,j)−IDRR(i,j). The similarity measure calculator 440 is also configured to apply upon each pixel of the difference image a pattern intensity function, defined by summing asymptotic functions of the gradients of the difference image over the pixels within a neighborhood R. R is defined so that the gradients of the difference image can be considered in at least four directions: a) a substantially horizontal direction; b) a substantially vertical direction; c) a substantially diagonal direction at about 45 degrees; and d) a substantially diagonal direction at about −45 degrees. The pattern intensity function is characterized by a mathematical formulation given by equations (5) and (6) above. The details of the motion field generator 450 have been fully described above in conjunction with FIG. 15. In one embodiment, the parameter determiner 460 is configured to determine a separate set of transformation parameters for each of pair of orthogonal projection x-ray image, formed by projecting the anatomical region onto respective projection image planes. In this embodiment, the non-rigid transformation parameters include three translational parameters (x, y, and z), and three rotational parameters (r, p, w), where (x, y, and z) represent the three translations of the treatment target along the directions of three mutually orthogonal x-, y-, and z-axes, respectively; and where (r, p, w) represent the three rotations (roll, pitch, yaw) of the treatment target about the three mutually orthogonal x-, y-, and z-axes. The parameter determiner 460 is further configured to combine the resulting parameters for each projection to obtain the 3D transformation parameters. The 3D transformation parameters are related to the transformation parameters for projections A and B by the following relationship: x=(xA+xB)/2, y=(yA−yB)/√{square root over (2)}, z=(yA+yB)/√{square root over (2)}, r=θx, p=(θB−θA)/√{square root over (2)}, w=(θB+θA)/√{square root over (2)} (17) Experiments in 2D/3D image registration, in accordance with the algorithm illustrated in the flow chart in FIG. 1, and with the method of motion field generation as described above, have been carried out using patient clinical data. In one embodiment, a CT resolution of 0.87×0.87×1.00 mm (256×256×300 voxels) has been used. FIG. 17A schematically illustrates target localization between a DRR of the target and an x-ray image of the target, in an embodiment in which the target is located within the cervical region of the spine. FIG. 17B schematically illustrates target localization between a DRR of the target and an x-ray image of the target, in an embodiment in which the target is located in the thoracic region of the spine. FIG. 17C schematically illustrates target localization between a DRR of the target and an x-ray image of the target, in an embodiment in which the target is located in the lumbar region of the spine. In order to evaluate the image registration algorithm, the target registration error (TRE) has been computed. The TRE is computed as the difference between the displacements obtained using the fiducial-less tracking, and the displacements using fiducial tracking: TRE=√{square root over ((dx−dx0)2+(dy−dy0)2+(dz−dz0)2)} (18) FIG. 18 is a table of TRE (target registration error) values for different targets located within the cervical, thoracic, and lumbar regions, in embodiments in which fiducials are kept in the CT scan. FIG. 19 is a table of TRE (target registration error) values for different targets located within the cervical, thoracic, and lumbar regions, in embodiments in which fiducials are removed in the CT scan. As seen from FIGS. 18 and 19, the mean for the TRE is less than 0.6, using the fiducial-less tracking method and system described in the present patent. In sum, a fiducial-less tracking method and system, based on non-rigid image registration, includes a system for automatically selecting an ROI within which the image registration is restricted. The ROI can be selected with little or no user interaction. The ROI is optimized to contain as much information as possible. To minimize user interaction, in one embodiment, a modified Shannon entropy is calculated, then maximized. While the invention has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
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<SOH> BACKGROUND <EOH>Image registration aims at finding an optimal transformation between different representations of one or more objects, i.e. between different images. Registration techniques can be useful in medical procedures in which a pre-operative image space needs to be properly correlated to a real-time physical space. In image-guided surgical procedures, for example, pre-operatively acquired images may have to be registered onto intra-operative, near real-time images. In this way, the surgeon can be guided during his operation by viewing, in real time, images of the anatomical region being treated and/or the surgical devices. In practice, a formal mathematical transformation may be determined that best aligns the pre-operative image coordinate system with the patient's physical world coordinate system, defined for example in the treatment room. The registration of preoperative 3D images onto real-time 2D projection images (e.g. 2D x-ray projection images) is often referred to as “2D-3D image registration.” 2D-3D image registration is widely used in image-guided surgical procedures. Because in general real-time x-ray images are merely 2D projections, the lack of 3D information can hinder accurate surgical guidance. Pre-operative 3D scans (e.g. CT scans or MRI scans) of the target region can provide the necessary 3D information. A robust and accurate 2D-3D registration algorithm is needed in order for the position of the anatomical target (and/or relevant surgical instruments), as viewed on the real-time 2D images, to be reliably correlated to their position as visualized through the pre-operative 3D scans. As one example, during radiotherapy or radiosurgery, 2D-3D registration can be used to properly direct radiation onto a tumorous target that is visible in the images. As another example, in a surgical navigation system, 2D-3D registration can be used to track in real time the changing position of a surgical probe on a display of the preoperative images. A known registration method is to identify corresponding features in each coordinate system. For example, fiducial markers may be attached to or implanted in the patient before the pre-operative images are acquired, for point-based alignment. The markers may be tracked using an optical localization device. Typically, these fiducial markers may be designed so that they can be accurately localized in the pre-operative image as well as in the physical world. The respective localization points may then used to calculate a rigid body transformation between the two coordinate systems. Fiducials-based tracking can be difficult for the patient, for a number of reasons. For example, high accuracy tends to be achieved by using bone-implanted fiducial markers, but less invasive techniques such as skin-attached markers or anatomical positions tend to be less accurate. Implantation of fiducials into a patient may be painful and difficult, especially for the C-spine, the implantation process for which may frequently lead to clinical complications. Therefore, a number of attempts have been made in the art to develop techniques for fiducial-less tracking. These known methods generally assume a rigid body transformation, i.e. a rigid body rotation and a rigid body translation. Such a rigid transformation typically ignores local variations during the transformation, and may assume that the patient's anatomy is a rigid body, and that all of the rigid body constraints should be preserved. A lot of clinical data has shown that the rigid transformation model may be inadequate in many cases. Accordingly, non-rigid registration algorithms may be required in order to account for real patient body deformation, and thus track an anatomical region more precisely. In non-rigid image registration, faster computation may be achieved by restricting the registration process to a region of interest (ROI) within the image being registered. It is known to select such ROIs through user interaction, for example through manual input by the user. The requirement of user interaction is, however, one of the undesirable features of the known fiducial-less tracking methods. It is desirable that a method and system be provided for automatically selecting an ROI within an image, without requiring user interaction. In this way, a fully automated non-rigid image registration could be performed, minimizing or effectively eliminating the need for user interaction during image registration.
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<SOH> SUMMARY <EOH>A method and system are presented for automatically selecting a region of interest within an image of an object. In this way, the need for user interaction can be minimized or eliminated, when performing non-rigid image registration between the image and a different image of the object. The object may be an anatomical region, containing a treatment target and one or more reference structures. The selected ROI contains the treatment target. In one embodiment, the ROI may be selected by defining a measure H of the image, the measure H being suitable for image registration, and selecting the region within the image in which the measure H is maximized. In this way, the ROI can be optimized to contain as much information as possible. In one embodiment, the measure H is an entropy measure, representative of image entropy. In one embodiment, the entropy measure H may be a modified Shannon entropy, defined by: in-line-formulae description="In-line Formulae" end="lead"? H=Σ =1 I=Imax I P ( I )log P ( I ), in-line-formulae description="In-line Formulae" end="tail"? where I is the value of the intensity of the first image, at each pixel of the first image, I max is the number of image intensity levels, and P(I) is the probability of an image intensity value I occurring within the ROI. In one embodiment, a computer-readable medium is presented that has stored therein computer-readable instructions for a processor, wherein the instructions, when read and implemented by the processor, may cause the processor to 1) input and store data representative of the intensity values of the pixels of an image; 2) calculate an entropy measure H of the image, using the input data; and 3) select an ROI within the image that maximizes H.
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20040630
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20070612
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20060105
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79100.0
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G06K932
| 0
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MACKOWEY, ANTHONY M
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ROI SELECTION IN IMAGE REGISTRATION
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UNDISCOUNTED
| 0
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ACCEPTED
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G06K
| 2,004
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10,881,211
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ACCEPTED
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System and method for consolidating, securing and automating out-of-band access to nodes in a data network
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A system and method for out-of-band network management is provided wherein one or more different management interfaces are converted into a common format management data. The system may encrypt the common format management data. The system may also authenticate each user that attempts to access the management interfaces.
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1. An out-of-band management system for computer networks, the system comprising: a plurality of network nodes manageable through a dedicated management interface other than the data transmission interfaces wherein the plurality of network nodes use at least two different types of management interfaces that generate management data; a management module, executing on a computer, that converts the different types of management interface management data into a common management data format and that communicates the common management data format to a network management system; and the network management system further comprising a web server application, executing on a computer, that generates a graphical user interface based on the common management data format and a web-browser that permits a user to access the management module. 2. The system of claim 1, wherein the management module further comprises a module with a plurality of computer instructions executed by the computer that converts one or more low-level protocols utilized by the management interfaces into one or more higher-level protocols suited for transmission over a TCP/IP network to the network management system. 3. The system of claim 1, wherein the management module further comprises a module with a plurality of computer instructions executed by the computer that encrypts the common management data in order to prevent the common management data from being intercepted when in transit to the network management system. 4. The system of claim 1, wherein the management module further comprises a module with a plurality of computer instructions executed by the computer that communicates with enterprise directory systems to authenticate a user before giving them access to the management interfaces. 5. The system of claim 1, wherein the management module further comprises a module with a plurality of computer instructions executed by the computer that detects a network management event and executes an action in response to the detection of the network management event. 6. An out-of-band network management method executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols, the method comprising: receiving management data from the one or more management interfaces; converting the management data of the one or more management interfaces into a common management data protocol; communicating the common management data to a network management system; publishing a graphical user interface based on the common management data on a web server; and permitting access to the management interfaces using a web-browser. 7. The method of claim 6, wherein converting the management data further comprises converting one or more low-level protocols utilized by the management interfaces into one or more higher-level protocols suitable for transmission over the TCP/IP network. 8. The method of claim 7, wherein the low-level protocols are one or more of an RS-232 protocol, a keyboard video mouse protocol, an intelligent platform management interface protocol, an integrated lights out interface protocol, an advanced lights out management interface protocol and a Blade center management protocol. 9. The method of claim 6 further comprising encrypting the common management data to generate encrypted management data that is communicated to the network management system to prevent the common management data from being intercepted when in transit. 10. The method of claim 6 further comprising authenticating a user before giving them access to the management application and the management interfaces. 11. The method of claim 6 further comprising detecting a pre-programmed event and executing an pre-programmed action upon the detection of the pre-programmed event. 12. An out-of-band network management apparatus executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols, the apparatus comprising: management means, executing on a computer system, for converting the one or more management protocols into a common management data protocol and for communicating that common management data to a network management system; and the network management system further comprising means, executing on a computer system, for publishing a graphical user interface based on the common management data and a web-browser utilized by the user to access the management application and the common management data. 13. The apparatus of claim 12, wherein the management means further comprises means for converting one or more low-level protocols utilized by the management interfaces into one or more higher-level protocols suitable for transmission over the TCP/IP network. 14. The apparatus of claim 13, wherein the low-level protocols are one or more of an RS-232 protocol, a keyboard video mouse protocol, an intelligent platform management interface protocol, an integrated lights out interface protocol, an advanced lights out management interface protocol and a Blade center management protocol. 15. The apparatus of claim 14, wherein the network nodes are one or more of a serial console server, a keyboard video mouse switch, an intelligent platform management interface device, an integrated lights out interface device, an advanced lights out management interface device and a Blade center management module. 16. The apparatus of claim 12 wherein the management means further comprises means for encrypting the common management data to generate encrypted management data that is communicated to the network management system to prevent the common management data from being intercepted when in transit. 17. The apparatus of claim 12, wherein the management means further comprises means for communicating with an enterprise authentication system in order to authenticate a user before giving them access to the management application and the management interfaces. 18. The apparatus of claim 17, wherein the enterprise directory system protocols comprise one of RADIUS, TACACS, SecureID, X509 certificates, Kerberos, NIS, Active Directory and LDAP. 19. The apparatus of claim 12, wherein the management means further comprises means for detecting a pre-programmed event and means for executing a pre-programmed action upon the detection of the pre-programmed event. 20. An out-of-band network management apparatus executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols, the apparatus comprising: a management application executing on a computer system that converts the one or more management protocols into a common management data protocol and communicates that common management data to a network management system; and the network management system further comprising a web server application executing on a computer system that publishes a graphical user interface based on the common management data and a web-browser utilized by the user to access the management application and the common management data. 21. The system of claim 20 wherein the management application further comprises a module that converts one or more low-level protocols utilized by the management interfaces into one or more higher-level protocols suitable for transmission over the TCP/IP network. 22. The system of claim 21, wherein the low-level protocols are one or more of an RS-232 protocol, a keyboard video mouse protocol, an intelligent platform management interface protocol, an integrated lights out interface protocol, an advanced lights out management interface protocol and a Blade center management protocol. 23. The system of claim 22, wherein the network nodes are one or more of a serial console server, a keyboard video mouse switch, an intelligent platform management interface device, an integrated lights out interface device, an advanced lights out management interface device and a Blade center management module. 24. The system of claim 20 wherein the management application further comprises a module that encrypts the common management data to generate encrypted management data that is communicated to the network management system to prevent the common management data from being intercepted when in transit. 25. The system of claim 20, wherein the management application further comprises a module that communicates with an enterprise authentication system in order to authenticate a user before giving them access to the management application and the management interfaces. 26. The system of claim 25, wherein the enterprise directory system protocols comprise one of RADIUS, TACACS, SecureID, X509 certificates, Kerberos, NIS, Active Directory and LDAP. 27. The system of claim 20, wherein the management application further comprises an automation module that detects a pre-programmed event and executes pre-programmed action upon the detection of the pre-programmed event.
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FIELD OF THE INVENTION This invention relates to the field of computer network management, and specifically to out-of-band network management systems that can transport management information over a network different from the data network being managed. BACKGROUND OF THE INVENTION Data center management professionals commonly use network management tools for monitoring and restoring the operation of network nodes such as computer servers, network appliances, security appliances, storage devices, sensors, and controls. These typical network management tools permits the professional to manage and restore the operations of the network nodes remotely. Typically, these network management tools are divided in two categories: in-band management tools and out-of-band management tools. An in-band management tool relies on the data network connected to the network nodes to transport the management information. An out-of-band management tool creates an alternative path to communicate with the network nodes using alternative hardware means such as dial up phone lines or separate networks that are used exclusively for management. The out-of-band management tool permits the supervisor to access the managed network nodes even when the network nodes lose network connectivity. The in-band management tools rely on network protocols, such as Simple Network Management Protocol (SNMP), which are commonly used to manage large networks. Several examples of commercial in-band management tools following that architecture are the HP® Open View, IBM® Tivoli, BMC® Patrol, and CA® Unicenter products. However, these in-band tools become ineffective whenever the data network associated with the network nodes fails or a managed device loses network connectivity. Thus, these in-band network management tools leave network administrators in a deadlock position (e.g., the device fails and brings the data network down and the administrator cannot reach the device because the data network is down). Examples of common causes of the deadlock position include software crashes, configuration errors, hardware malfunctions caused by power surges, need to upgrade firmware and/or network failures. Thus, failures that cause the network node to be disconnected from the data network require a human operator to travel to the location where the network node is located so that the human operator can interact with the piece of failing equipment through a terminal directly connected to a management port or actuate physical control switches to restore functionality of the failing equipment. The need to have a human operator travel to the location of the network node is expensive, causes a great amount of time to be spent by the human operator, and causes business losses by causing long data network downtime. To overcome this limitation of in-band network management tools, systems were created that enable the remote access to the out-of-band management ports and other control functions of the network node, such as power-cycling, monitoring of temperature and other health indicators, without the need for a human operator to physically travel to the location where the incident occurred. Typically, the physical interfaces for out-of-band access includes serial consoles, KVM ports, power circuits, temperature and humidity probes and/or remote actuators. While effective, the building of an alternative, independent network using different connection media for out-of-band access increases the cost of building a data center. In an effort to standardize the physical interface and reduce the cost of out-of-band access, an industry consortium has developed an interface called Intelligent Platform Management Interface (IPMI). Other vendors have created similar proprietary interfaces. For example, HP® has its Integrated Lights-Out (ILO) interface and Sun Microsystems® has its Advanced Lights Out Module (ALOM) interface. The protocols for these interfaces are well known. These out-of-band management interfaces can only be used with certain types of network nodes and define a protocol above TCP/IP and utilize common Ethernet media for transport of the management information. Both legacy and newer out-of-band interfaces and protocols lack the robustness and security features to be transported beyond the local management network. Thus, there is a need for aggregators or gateways that consolidate one type of access interface and can provide the authentication and encryption functions required for remote network management. Examples of those aggregators include console servers (aggregators for serial console), KVM-over-IP switches (aggregators for keyboard-video-mouse ports), intelligent power distribution units (aggregators for power control circuits), IPMI gateways (aggregators for IPMI interfaces), etc. Several commercial products exist to aggregate each type of access interface/physical media and provide remote access. The resulting conventional situation is a typical heterogeneous data center that utilizes a plurality of disparate systems for a complete management solution of new and legacy systems. In addition to the in-band management tools, data center managers utilize console servers (for Unix/Linux systems, network equipment and automation devices), KVM-over-IP switches (for Windows servers), intelligent power control units (for remote power control), environmental monitoring and the software systems associated with each type of out-of-band interface. This increases the cost to implement and the complexity to operate management systems for data networks, requires a great amount of training, fosters problems caused by operator errors, and increases the time needed to correlate incidents from different management systems and restore network services. Thus, it is desirable to provide a system and method for securing, consolidating and automating out-of-band access to network nodes in a data network wherein various different protocols and interfaces are supported and it is to this end that the present invention is directed. SUMMARY OF THE INVENTION The invention is a system that provides a single common aggregation point for a plurality of out-of-band interfaces, offering consolidation close to the managed devices that avoids the transport of disparate data streams across the corporate and public networks. The system also provides a single graphical user access interface to the out-of-band infrastructure, independent of physical interface, through any computer connected to the data network directly or to the system that embodies this invention through a modem connection. The system also provides a single encryption and user authentication model, integrated to other enterprise security mechanisms, to secure the management data and prevent unauthorized access to the management ports independent of the out-of-band physical media. The system also provides local incident correlation capabilities that are independent of a centralized network management system so that it is possible to automate the execution of pre-programmed actions in response to pre-programmed events. The system also provides integration between the out-of-band domain and the high-level network management systems so that data center management can be consolidated in one single system. The present invention comprises a system and method for securing, integrating, automating and consolidating out-of-band management independent of the physical and logical interfaces in use. The system includes a connection mechanism that supports at least two interfaces selected from the group consisting of: serial consoles, KVM ports, power circuits, sensors and controls, Telnet and SSH, Intelligent Platform Management Interface (IPMI), Integrated Lights Out (ILO), Advanced Lights Out Management (ALOM). Thus, in accordance with the invention, an out-of-band management system for computer networks is provided. The system comprises a plurality of network nodes manageable through a dedicated management interface other than the data transmission interfaces wherein the plurality of network nodes use at least two different types of management interfaces that generate management data. The system also has a management module, executing on a computer, that converts the different types of management interface management data into a common management data format and that communicates the common management data format to a network management system. The network management system further comprises a web server application, executing on a computer, that generates a graphical user interface based on the common management data format and a web-browser that permits a user to access the management module. In accordance with another aspect of the invention, an out-of-band network management method executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols is provided. Using the method, management data from the one or more management interfaces is received and the management data of the one or more management interfaces is converted into a common management data protocol. The common management data is communicated to a network management system that publishes a graphical user interface based on the common management data on a web server and permits access to the management interfaces using a web-browser. In accordance with another aspect of the invention, an out-of-band network management apparatus executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols is provided. The apparatus has management means, executing on a computer system, for converting the one or more management protocols into a common management data protocol and for communicating that common management data to a network management system. The network management system further comprising means, executing on a computer system, for publishing a graphical user interface based on the common management data and a web-browser utilized by the user to access the management application and the common management data. In accordance with yet another aspect of the invention, an out-of-band network management apparatus executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols is provided. The apparatus comprises a management application executing on a computer system that converts the one or more management protocols into a common management data protocol and communicates that common management data to a network management system. The network management system further comprises a web server application executing on a computer system that publishes a graphical user interface based on the common management data and a web-browser utilized by the user to access the management application and the common management data. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a typical out-of-band network management system; FIG. 2 is a diagram illustrating an out-of-band network management system in accordance with the invention; FIG. 3 is a diagram illustrating more details of the management module of the out-of-band network management system in accordance with the invention; FIG. 4 is a diagram illustrating a method for managing the management data connection interfaces in accordance with the invention; FIG. 5 is a screenshot illustrating the login screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 6 is a screenshot illustrating an access control screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 7 is a screenshot illustrating a serial console screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 8 is a screenshot illustrating a KVM console screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 9 is a screenshot illustrating a power control console screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 10 is a screenshot illustrating a power and console integrated interface screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 11 is a screenshot illustrating a data logging screen of an exemplary out-of-band network management system in accordance with the invention; FIG. 12 is a screenshot illustrating an alarm handling screen of an exemplary out-of-band network management system in accordance with the invention; and FIG. 13 illustrates an example of automated alarm handling method of an exemplary out-of-band network management system in accordance with the invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The invention is particularly applicable to an out-of-band network management system that interfaces with specific managed devices set forth below over the Internet and it is in this context that the invention will be described. It will be appreciated, however, that the system and method in accordance with the invention has greater utility since the system may be used with any existing interfaces and protocols as well as any newly developed interfaces and protocols. FIG. 1 is a diagram illustrating a typical out-of-band network management system 20. The system 20 has one or more out-of-band monitor devices 22, such as an RS-232 device 221, KVM device 222 and a IPDU device 22N. Each of these devices 22 typically has one or more pieces of software 24 loaded onto the device that perform some functions/operations. In this typical system, each device 22 monitors a particular type of managed device using a particular protocol, such as the RS-232 box is used to monitor and manage Linux and Unix servers and network equipment using the well known RS-232 protocol. As another example, the KVM device is used to monitor Windows boxes with a well known KVM protocol. In this system, each device 22 monitors and manages a particular managed device or group of managed devices 30, including but not limited to Unix Servers, Windows Servers, Blade Servers and Blade chassis, Telecom equipment, network routers, switches, load balancers, network attached storage and remote access servers, and generates management data about that group of managed devices. In the example shown in FIG. 1, the managed devices 30 include Unix, Linux and networking devices 301 that are managed using the RS-232 protocol, the Windows systems 302 that are managed using the KVM protocol, servers and network automation devices 303 that are managed using the power protocol, IPMI enabled servers 304 that are managed using the IPMI protocol and other managed devices 30N. As shown, each device may utilize a different protocol, such as the RS-232 protocol, the KVM protocol, the power device protocol, the IPMI protocol etc. The management data generated by each device 22 has its own unique protocol and format. Thus, each device 22 consolidates the out of band management data, but focuses on a single type of media, such as a serial console by MRV or Lantronix, a KVM console by Avocent, an IPMI console by Intel, Blades by IBM, etc. . . . Then, the consolidation of the management data occurs at the network management system (and not close to each managed device). The management data for each device 22 represents the consolidated data for the types of managed devices 30 managed by that particular device. The management data from the managed devices is then sent over a communications network 26, such as the Internet, wide area network, local area network, any combination of these networks or any other communications network, to a network management system 28 or a network management workstation 29 whose operation, features and functions are well known. In this typical system, the management data communicated between the devices 22 and the network management system 28 is not encrypted or the data must be encrypted at each device 22 resulting in a laborious process or no encryption. This system also requires that the various different management data from the different devices 22 is consolidated at the NMS 28 so that the various data stream must pass over the communications network which results in a tremendous amount of data traffic over the communications network. In addition to the disadvantages of transporting multiple data streams over a network, the consolidation at the NMS 28 requires the user (or the NMS system) to authenticate/login into each different system separately which is inconvenient, time consuming and results in lower overall system security. An out-of-band network management system in accordance with the invention allows for a single authentication/login process to control access to all devices, independent of access media. The existing media-specific consolidation systems are not extensible by design to support multiple access media and, as a consequence, while not preventing the co-existence of legacy and new network devices using different access medias, the existing systems do not facilitate such co-existence. The result is an increase in the complexity of the network systems and the creation of a barrier to new technologies. An out-of-band network management system in accordance with the invention that overcomes these limitations of typical systems will now be described. FIG. 2 is a diagram illustrating an out-of-band network management system 34 in accordance with the invention. As with FIG. 1, the system may be used to manage various managed devices/groups of managed devices 30 that use different management protocols as shown. The equipment being managed in accordance with the invention includes, but is not limited to, Unix Servers, Windows Servers, Blade Servers and Blade chassis, Telecom equipment, network routers, switches, load balancers, network attached storage and remote access servers that are being accessed using a multitude of access devices and protocols including but not limited to Serial Console Servers, Keyboard Video Mouse switches, Intelligent Platform management Interface, HP Integrated Lights out interface, SUN Advanced Lights out Management interface, IBM Blade Center management module. Broadly, the invention allows users (at the network management system 28 or workstation 29, to control power, access the system management interface, record and create alerts based on internal sensors and system log messages. The invention provides a single secure point of access to the managed devices 30 through the managed network and allows centralized enforcement of security policy in regard to authentication, authorization, accounting and encryption. A standard user interface is implemented which allows access to the above mentioned features independent of the connection technology or technologies being used by each system. In accordance with the invention, the out-of-band network management system 34 further comprises a management module 40 that may be one or more software modules each comprising a plurality of lines of computer code that implement the functions of the management module described below. In an exemplary implementation of the system 34, the management module is the Alterpath Manager product that is sold by Cyclades Corporation. In accordance with the invention, the management module 40 may be executed on a computing resource with sufficient memory and processing power to implement the management module, such as a server for example. As shown in FIG. 2, the management module 40 consolidates the management data from the various managed devices 301-30N with the various different protocols and converts the management data into a common format as described below in more detail so that the management data of the managed devices is consolidated closer to the managed devices. The management module may also encrypt the management data using well known techniques and then communicate the data over the communications network 26 using well known protocols. Thus, the management module is able to enforce a security protocol for all of the management data. The management module also eliminates the transmission of the management data with the plurality of different protocols over the communications network 26 so that the total amount of data communicated over the communications network 26 is reduced. In a preferred embodiment, the encrypted or unencrypted management data from the management module is communicated to the network management system 28 and/or workstation 29 using the well known simple network management protocol (SNMP), a web server and/or an SSH protocol. In accordance with the invention, the protocol used to communicate the management data from the management module to the network management system 28 may be changed/updated to any protocol without departing from the scope of the invention. As shown in FIG. 2, each group of management devices 30 communicates using a particular protocol and a particular connection type. For example, the Unix, Linux and networking devices 301 utilize an RS232 protocol transported over a Telnet/SSH link by a console server while the Windows devices 302 utilize a KVM protocol over a Web proxy link. The servers and network automation devices 303 utilize a command line interface (CLI) protocol and the IPMI enabled devices 304 use the well known IPMI protocol. In accordance with the invention, users of the system 34 access the managed systems through a single secure and consolidated user interface, such as using a typical web browser (not shown) with the addition of a command line interface. A further interface provides services to proxy and translate information from the managed network which is passed to existing Network management systems. In accordance with the invention, the management module 40 may include one or more drivers (not shown) that permit the management module to interface with the various different management protocols. The management module 40 further comprises a web user interface module (not shown) that may be accessed using the well known HTTP or HTTPS protocols, a command line interface module (not shown) that may be accessed using the well known SSH or Telnet protocols and a messaging interface module (not shown) that provides connectivity for the management module 40 with known in band network management systems. FIG. 3 is a diagram illustrating more details of the management module 40 of the out-of-band network management system in accordance with the invention. The management module may comprise a management application module 42 and a universal connectivity module 44 wherein each of these modules may comprise, in a preferred embodiment, a plurality of lines of computer code that are executed on a computing resource, such as a server computer, that implement the functions of the management module. In general, the management application module will handle device management, device control and event handling functions. The management application module may also typically include interfaces to known network management systems, such as HP® OpenView, IBM® Tivoli, CA® Unicenter and BMC® Patrol for example. The universal connectivity module 44 may implement one or more services wherein the services include but are not limited to connection to management consoles, update of management console firmware, configuration of management interfaces, power control, alarm collection, and translation from standard protocols such as SNMP to proprietary protocols such as HP iLO. In more detail, the universal connectivity module 44 may handle requests from the management application module 42 and will translate service requests into protocol specific interactions with the various supported management interfaces and protocols. For example, a NMS or system administrator may want to power cycle a certain network node to recover it from a catastrophic software failure. The system may provide a single interface that enables the “power cycle” command. This command can be translated by the system into a command line send over a serial interface to an Intelligent Power Distribution Unit (IPDU) (in case the device is connected for power control through an external IPDU), or into an IPMI command transmitted over a network interface (in the case the device is IPMI enabled) or into an ALOM command line interface sent over a Telnet connection (if the device to be power cycled is an ALOM-enabled Sun server.) As another example, the system may identify network events generated by network nodes using a variety of protocols: clear text on the console part of a router, an alarm received from a server over the IPMI protocol, a sensor reading from a temperature sensor, etc. All of those events are processed through a single engine and displayed/managed on a single interface by the user. Since each type of management interface may use different protocols, encryption methods, authentication methods, command syntax etc, the universal connectivity module 44 may perform all necessary translations in both directions to allow the management application module 42 to utilize the services of the management interface in a standard and uniform way. In accordance with the invention, the management interfaces supported using the universal connectively module 44 is not limited to the management interfaces shown since, when a new management interface is developed/implemented/promulgated, a new module may be incorporated into the universal connectivity module 44 to handle the new management interface. The universal connectivity module 44 simplifies the process of creating management and other applications that require access and control of a plurality of management interfaces in equipment including but not limited to Unix servers and workstations, Linux servers and Workstations, Microsoft Windows servers and workstations, network routers, network switches, firewalls, telecom switches, storage devices, Blade servers, computer clusters. In more detail, the application module 42 may further comprise a network management system integration module 46, a user management module 48, an event management module 50, a power management module 52, a change management module 54 and a patch management module 56 wherein each module comprises, in a preferred embodiment, a plurality of lines of computer instructions that implement the function of the particular module. The network management system integration module 46 permits the management module 40 to integrate with other well known network management systems as described above and the user management module 48 permits the network management system 34 to perform various user related functions such as user authentication and security, user login, user database management, etc. . . . The event management module 50 permits the management module 40 perform automatic network management event detection and automatic action execution in response to the detected event and the power management module 52 permits the management module 40 to control the power of the managed devices 30. The change management module 54 permits the centralization of configuration information for other elements of the out-of-band management network, such as console servers, KVM switches, IPDUs, IPMI, iLO agents, etc. while the patch management module 56 permits the automated control and update of firmware patches for other elements of the out-of-band management network, such as console servers, KVM switches, IPDUs, IPMI, iLO agents, etc. In accordance with the invention, the universal connectivity module 44 may further comprise a KVM/IP module 60 that permits the management module 40 to interface with a well known KVM management interface, a serial console module 62 that permits the management module 40 to interface with a well known RS-232 management interface, a IPMI module 64 that permits the management module 40 to interface with a well known IPMI management interface, a iLO module 66 that permits the management module 40 to interface with a well known iLO management interface, a blade module 68 that permits the management module 40 to interface with a well known Blade management interface, a UPS module 70 that permits the management module 40 to interface with a well known uninterruptible power supply management interface and a PDU module that permits the management module 40 to interface with a well known PDU management interface. As described above, further modules in the universal connectivity module 44 may be added to accommodate new management interfaces. Each of the modules comprises, in a preferred embodiment, a plurality of lines of computer instructions that implement the API for the particular management interface. For example, the control by a power management module 52 (see below) of a power management device, such as the Cyclades PM device. The Cyclades PM is connected with an RS232 serial connection to a Cyclades TS console server wherein the Cyclades PM is being used to control power to several servers. The power management module 52 may issue the following command: Power Off(Cyclades PM, IP Address, TCP Port, Outlet, Username, Password, SSH). In accordance with the invention, the system loads the Cyclades PM driver (that will translate the command into the corresponding command for the Cyclades PM device by: 1) opening an SSH connection to the IP address and Port Number; 2) login as the Username with the Password; 3) issue the command to power off the Outlet (pm off outlet); and 4) provide feedback to the application of the results code for the command. The actual commands generated by on the above command would be: ssh user:port@IP Address pm off outlet read exit code Thus, the original command above is converted into the set of commands listed in order to achieve the desired operation of the power management device. FIG. 4 is a diagram illustrating a method 80 for managing the management data connection interfaces in accordance with the invention. In step 82, an application request is received by the universal connectivity module 44 wherein the module 44 loads a driver on demand for any supported interface type and processes the service request from the application. With the application request, the module 44 will receive information from the application indicating which type of interface is to be used and also which service is required. Thus, in step 84, the module 44 may determine if the requested module is of the KVM type and the load the KVM module in step 86 or proceeds to step 88. If the module is identified and loaded, then in step 90, the requested action is performed and the module is unloaded in step 92. In step 88, the module 44 determines if the requested module is of the serial type and then loads the serial module in step 94 or proceeds to step 96. In step 96, if the requested module is not of the KVM or serial type, the module 44 determines if the requested module is of the IPMI type and loads the IPMI module in step 98 if the IPMI module was requested. In step 100, the module 44 determines if the requested module is of the iLO type and load the iLO module in step 102 if the iLO module was requested or proceed to step 104 in which the module 44 determines of the requested module is the Blade type module. If the Blade type module is requested, then in step 106, the Blade module is loaded. In step 108, the module 44 determines if the requested module is of the UPS type and that module is loaded in step 110 if the UPS module was requested. Thus, the module 44 loads the appropriate module type which will perform all necessary communication with the management interface using the specific protocol as required by the interface. In accordance with the invention, all necessary protocol and data format conversions are performed by the module 44 to allow transparent access for the application to the supported services of the specific interface type. In one exemplary embodiment, the module 44 may provide support for interface types including but not limited to KVM over IP, serial console server, HP iLO, Intelligent Platform Management Interface (IPMI), Intelligent Power Distribution units (IPDU), IBM Blade Center and Sun Advanced Lights Out Management. It can also be seen that future management interfaces and protocols can be easily integrated into this structure by the addition of a protocol specific driver/module which will handle all necessary protocol and data conversions allowing a standard API to be used from the application layer which will remain unchanged. The main purpose of the universal connection module 44 is to manage the different connection types and protocols employed by each different system management interface. An example of the functionality and services provided by the universal connection module 44 may include session setup, session teardown, authentication of sessions, encryption of data, transport of data, conversion of command syntax, transport of system status (temperature, voltages, fan speed etc) and power control. To illustrate the differences between the management interfaces, several examples of management interface types and their capabilities will be described in more detail. Serial Console A serial console communicates using ASCII coded characters over a serial RS232 interface. In addition, support is available for transmission of special non-ASCII characters such as the Break signal that is utilized by the management console of Sun Server and Cisco Routers (among others). The serial console management interfaces are normally found in network equipment such as routers and switches as well as in Unix and Linux computer systems. The serial console driver/module 62 of the universal connectivity module must be capable of converting the ASCII coded RS232 serial stream to a format suitable for transmission to the central management application. The conversion of the serial console data stream to TCP/IP packets is normally performed by a device knows as a console server such as the Cyclades ACS family and the universal connectivity module is capable of converting these TCP/IP packets back to a serial stream for processing by the application layer/modules. The driver/module 62 may also accommodate the transmission of special characters such as the break signal. In a preferred embodiment of the system, the transport used is Telnet or SSH. The universal connectivity module may also handle connection setup and teardown following the normal Telnet and SSH protocols. The universal connectivity module is also capable of performing the necessary authentication to access the management console which can take many forms including but not limited to Radius, TACACS+, SecureID, SSH key, NIS, Kerberos, X509 certificates, Active director or LDAP. ASCII, RS232, Telnet, SSH Secure Shell, TCP/IP, and Break signals are all commonly known terms and protocols specified in various international standards and RFCs. For more information see EIA232E of the RS232 Standard which is incorporate herein by reference, RFC854 for the Telnet Protocol Specification which is incorporated herein by reference and the ANSI X3.4-1986 and other variations for ASCII standards which is incorporated herein by reference. KVM Console The KVM (Keyboard Video Mouse) console is the management interface used to commonly communicate with graphical user interfaces such as those found in Microsoft Windows systems. The KVM console requires the keyboard, video and mouse signals of a computer system to be digitized and packetized for transmission over an IP network and this task is normally performed by a typical KVM/IP switch such as the Cyclades KVMnet product line. The universal connectivity module 44 is responsible for session setup and teardown, authentication and encryption settings, and network forwarding in order to load the KVM viewer application in the client workstation and transport the packetized KVM data to the client. In one example, the video interface is typically VGA and the keyboard and mouse interfaces may be PS/2 or USB which are both well known and understood standards. Intelligent Power Distribution Unit (IPDU) An Intelligent power distribution unit is a device which can power various types of equipment and has the capability to switch each power outlet on or off based on command received through its command interface. Typical examples of an IPDU are the Cyclades PM10 and APC products. The IPDU may have a command interface based on command line instructions or may be a based on a text menu architecture. In some cases, the command interface is based on SNMP commands or some proprietary protocol. In accordance with the invention, the universal connectivity module 44 may convert management application/module instructions such as PowerON and PowerOff into device specific instructions which may be transported over Ethernet or over serial RS232 connections depending on the specific device being controlled. The universal connectivity module may also need to use device specific command sets or protocols to translate the standard API commands to device specific commands and sequences. The universal connectivity module in this case may also deal with authentication and encryption of data. HP iLO The HP iLO (Integrated Lights Out) is a management interface for HP servers and blades which utilizes Ethernet as a transport. It provides several user interfaces including text console (accessible via Telnet), KVM console (accessed using a proprietary client), power control of the server (controlled using a proprietary protocol), system health monitoring, virtual media. The universal connectivity module 44 (and the iLO module 66) may perform necessary authentication to grant access to these resources and will convert data streams as required. The text console traffic may be converted from the Telnet format to a plain serial stream before being passed to the application layer. Any power control messages (PowerOn, PowerOff) received from the user application will be converted to corresponding iLO command sequences and transmitted to the iLO interface. The KVM application client software will be transported to the client workstation and after authentication will establish the connection between the user workstation and the server. The HP iLO management interface is documented at http://h18013.www1.hp.com/products/servers/management/ which is incorporated herein by reference. IPMI (Intelligent Platform Management Interface) IPMI is an emerging standard developed by Intel which deals with the management of computer equipment. IPMI provides a specification for connection to Text consoles, reading of system hardware status such as fan speed etc, and power control of the equipment. The universal connectivity module may translate requests from the application for Power control, system status and management console access to the IPMI protocol format and will deal with session setup/teardown, authentication, and encryption settings. IPMI is documented at http://www.intel.com/design/servers/ipmi/ which is incorporated herein by reference. Other Management protocols and Interfaces In accordance with the invention, other management protocols and interfaces (or any newly developed management interfaces may be handled in a similar way by the universal driver in order to provide a standard interface for the application layer to all supported features of the management interface. In each case the universal connectivity module will handle all call setup/teardown, authentication, encryption, conversion of data formats and protocols. Now, several examples of user interfaces of an exemplary out-of-band network management system in accordance with the invention are described. FIG. 5 is a screenshot illustrating the login screen 120 of an exemplary out-of-band network management system in accordance with the invention. As described above, the system provides centralized user authentication for all of the management consoles/interfaces supported by the system. In some management consoles, such as HP iLO, the type of authentication that is natively supported is not sufficient for the enterprise and thus the invention allows for standard enterprise class authentication and security to be enforced for any management interface independent of the protocols and authentication schemes that it natively supports. This is achieved by use of network proxy features that allow connection to consoles only when the user is properly authenticated and authorized to do so. FIG. 6 is a screenshot illustrating an access control screen 130 of an exemplary out-of-band network management system in accordance with the invention. The access control screen provided consolidated access control since all of the management consoles can be viewed and accessed in a standard and uniform way. The universal connectivity module will perform the necessary addressing and connection setup as well as performing relevant encryption and authentication to the end point device itself. Since each management interface may use a different protocol and require different client applications, the management consoles are consolidated, in accordance with the invention, using the universal connectivity module to perform the required authentication and encryption proxy services so that each device appears to have a common set of features. The screen contains one or more rows 132 of data about each supported console and permits the user to navigate between the management consoles. Within each row is a link 134 (the text of which is the name of the particular management console) that permits the user to launch the applications/clients in order to interact with the particular management console such as shown in FIG. 7. FIG. 7 is a screenshot illustrating a serial console screen 140 of an exemplary out-of-band network management system in accordance with the invention. In particular, an example of the launching of an embedded Secure Shell (SSH) client 142 is shown that permits the user to access a serial RS232 Management console. The client 142 is launched by clicking on the Management Console name link 134 in the screen 130 shown in FIG. 6. As shown, the SSH client 142 provides the user with a typical Linux command line interface for the serial management console. FIG. 8 is a screenshot illustrating a KVM console screen 150 of an exemplary out-of-band network management system in accordance with the invention. In this screen, from the initial login screen, the user may click on the link 134 corresponding to a KVM management console that thus launch a Keyboard Video Mouse (KVM) viewer application 152. The KVM viewer application may also be launched by selecting the KVM application from a listing of management console types. In accordance with the invention, when the viewer application 152 is launched, a connection is dynamically established to the device and authentication and encryption proxy services are performed. FIG. 9 is a screenshot illustrating a power control console screen 160 of an exemplary out-of-band network management system in accordance with the invention. As with the above examples, the user connects to this management console using the standardized uniform interface and has access to a standard set of features for power control such as an outlets manager application/screen (shown in FIG. 9), a view IPDUs information application/screen, a users manager screen/application, a configuration application/screen and a software upgrade application/screen. The universal connectivity manager hides the complexities of connecting to the power devices which in this case could be serial power strips or controlled by SNMP or they could be integrated in a service processor on the target system using IPMI, HP iLO, or SUN ALOM. Each power management protocol requires different session setup and teardown and each may have different levels of security and different command syntax. The invention abstracts this level of complexity allowing any type of power device to be supported by the same application. FIG. 10 is a screenshot illustrating a power and console integrated interface screen 170 of an exemplary out-of-band network management system in accordance with the invention. In this example, the user interface incorporates two completely separate console types. In the example shown in FIG. 10, an IPMI serial over LAN connection provides access to a Linux system console and power control is provided by a Cyclades PM serial Intelligent Power Distribution Unit so that the invention allows each management console type to be used in any context where it is valid. Thus, power control for instance could be provided by an Intelligent Power Distribution unit using SNMP protocol or an ALOM interface using the SUN ALOM protocol. FIG. 11 is a screenshot illustrating a data logging screen 180 of an exemplary out-of-band network management system in accordance with the invention. This service is provided by the universal connectivity module for any device or protocol that utilizes ASCII coded characters in its management interface. Thus, the data logging may be used with management interfaces such as RS232 serial or it may be a network connected Secure Shell (SSH) session or it may be using IPMI Serial over LAN protocol (among others). The universal connectivity module provides a serialized data stream to the application independent of the underlying protocols and transport mechanisms used to carry the data from its source. FIG. 12 is a screenshot illustrating an alarm handling screen 190 of an exemplary out-of-band network management system in accordance with the invention. Thus, the invention provides access to alarm conditions in the underlying management interfaces. These alarms may be transported using SNMP or may be detected by the examination of management console output or may be transported over IPMI etc. The universal connectivity module may allow the detection of each event and translate these to a standard format for use by the application. A common feature in the alarm handling is to provide a proxy service for existing Network Management and Incident Management systems. As shown in FIG. 12, each alarm may permit the user to drill down into the alarm and learn more about its data. Thus, the user can select a console name link 192 to look at the particular console, a ticket link 194 to look at a particular alarm ticket, a trigger name link 196 to look at the particular trigger name details or a console log link 198 to look a the log for the particular console. Now, a method for automated alarm handling will be described in more detail. FIG. 13 is a screenshot illustrating an example of automated alarm handling method 200 of an exemplary out-of-band network management system in accordance with the invention. The invention also allows for localized automated alarm handling. Without the invention, each alarm would be transported to a Network Management system (if a protocol converter were available for that type of device) in order to highlight a problem to an operator. The operator would then use a different application (utilizing a different authentication scheme, connection method, and transport protocol) to access the device to resolve the problem. This approach requires the Network Operation Center or system administrator to have access to multiple client software, and in order to interact with each management interface type the user must install and maintain different protocol stacks utilized by each management interface, use different authentication databases and maintain different passwords or make changes to security policy to accommodate new interface types. Using the invention, the various access types, authentication types and client management applications are hidden from the public network and are all contained within the invention. For example if a Windows machine crashes and produces a Blue Screen then the invention will detect the problem using XML coded messages received from the Microsoft Windows Emergency Management services module (EMS) in the windows server. This requires that the management console is connected using its access method which is most probably via a serial console server and that the Windows EMS Module is loaded for this port. Once the Alarm condition is recognized, a suitable response would be to power cycle the system. Thus, using the universal connectivity module, a local connection can now be made automatically using an appropriate power controller module. The power control module may be using SNMP over an Ethernet connection or may be using a command line chat script to communicate and control the power control module. Once the universal connectivity module establishes the connection then the power cycle command will be sent automatically by the alarm module to power cycle the system. The data logging service of the universal connectivity module will now be utilized to record the power on messages generated for the affected server and finally the EMS module will detect that the Windows Operating System is now rebooted. An external even can now also be generated to inform the Network Operation Center that the system had crashed, was rebooted and is now operational again. Thus, as shown in FIG. 13, the universal connectivity module allows communication to multiple device types to achieve alarm monitoring, power cycling and data logging. In each case, a different protocol module and service module may be required. However, since all of the modules are accessible using the universal connectivity module, the alarm event and response can be handled locally by the universal connectivity module. In this example, all of the functions and operation described herein are being performed by one or more modules of the management module 40 of the system. Thus, in step 202, the monitoring of a device is started by the universal connectivity module. In step 204, the alarm management software module is loaded. In step 206, a Blue screen condition for a Windows-based system is detected by the alarm module. In step 208, the system detects that condition and performs an automated response (a power cycle of the device in this example) in step 208. In step 210, the power module is loaded to perform the power cycle of the device in step 212. In step 214, the management module records the reboot results. In step 216, the management module loads the data log module and waits in step 218 for the system to become stable. In step 220, the alarm module is loaded again to determine if the originally detected event/trigger is still occurring. In step 222, the management module may send a notification to the network management system about the automated alarm handling and the results of that automated alarm handling. While the foregoing has been with reference to a particular embodiment of the invention, it will be appreciated by those skilled in the art that changes in this embodiment may be made without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Data center management professionals commonly use network management tools for monitoring and restoring the operation of network nodes such as computer servers, network appliances, security appliances, storage devices, sensors, and controls. These typical network management tools permits the professional to manage and restore the operations of the network nodes remotely. Typically, these network management tools are divided in two categories: in-band management tools and out-of-band management tools. An in-band management tool relies on the data network connected to the network nodes to transport the management information. An out-of-band management tool creates an alternative path to communicate with the network nodes using alternative hardware means such as dial up phone lines or separate networks that are used exclusively for management. The out-of-band management tool permits the supervisor to access the managed network nodes even when the network nodes lose network connectivity. The in-band management tools rely on network protocols, such as Simple Network Management Protocol (SNMP), which are commonly used to manage large networks. Several examples of commercial in-band management tools following that architecture are the HP® Open View, IBM® Tivoli, BMC® Patrol, and CA® Unicenter products. However, these in-band tools become ineffective whenever the data network associated with the network nodes fails or a managed device loses network connectivity. Thus, these in-band network management tools leave network administrators in a deadlock position (e.g., the device fails and brings the data network down and the administrator cannot reach the device because the data network is down). Examples of common causes of the deadlock position include software crashes, configuration errors, hardware malfunctions caused by power surges, need to upgrade firmware and/or network failures. Thus, failures that cause the network node to be disconnected from the data network require a human operator to travel to the location where the network node is located so that the human operator can interact with the piece of failing equipment through a terminal directly connected to a management port or actuate physical control switches to restore functionality of the failing equipment. The need to have a human operator travel to the location of the network node is expensive, causes a great amount of time to be spent by the human operator, and causes business losses by causing long data network downtime. To overcome this limitation of in-band network management tools, systems were created that enable the remote access to the out-of-band management ports and other control functions of the network node, such as power-cycling, monitoring of temperature and other health indicators, without the need for a human operator to physically travel to the location where the incident occurred. Typically, the physical interfaces for out-of-band access includes serial consoles, KVM ports, power circuits, temperature and humidity probes and/or remote actuators. While effective, the building of an alternative, independent network using different connection media for out-of-band access increases the cost of building a data center. In an effort to standardize the physical interface and reduce the cost of out-of-band access, an industry consortium has developed an interface called Intelligent Platform Management Interface (IPMI). Other vendors have created similar proprietary interfaces. For example, HP® has its Integrated Lights-Out (ILO) interface and Sun Microsystems® has its Advanced Lights Out Module (ALOM) interface. The protocols for these interfaces are well known. These out-of-band management interfaces can only be used with certain types of network nodes and define a protocol above TCP/IP and utilize common Ethernet media for transport of the management information. Both legacy and newer out-of-band interfaces and protocols lack the robustness and security features to be transported beyond the local management network. Thus, there is a need for aggregators or gateways that consolidate one type of access interface and can provide the authentication and encryption functions required for remote network management. Examples of those aggregators include console servers (aggregators for serial console), KVM-over-IP switches (aggregators for keyboard-video-mouse ports), intelligent power distribution units (aggregators for power control circuits), IPMI gateways (aggregators for IPMI interfaces), etc. Several commercial products exist to aggregate each type of access interface/physical media and provide remote access. The resulting conventional situation is a typical heterogeneous data center that utilizes a plurality of disparate systems for a complete management solution of new and legacy systems. In addition to the in-band management tools, data center managers utilize console servers (for Unix/Linux systems, network equipment and automation devices), KVM-over-IP switches (for Windows servers), intelligent power control units (for remote power control), environmental monitoring and the software systems associated with each type of out-of-band interface. This increases the cost to implement and the complexity to operate management systems for data networks, requires a great amount of training, fosters problems caused by operator errors, and increases the time needed to correlate incidents from different management systems and restore network services. Thus, it is desirable to provide a system and method for securing, consolidating and automating out-of-band access to network nodes in a data network wherein various different protocols and interfaces are supported and it is to this end that the present invention is directed.
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<SOH> SUMMARY OF THE INVENTION <EOH>The invention is a system that provides a single common aggregation point for a plurality of out-of-band interfaces, offering consolidation close to the managed devices that avoids the transport of disparate data streams across the corporate and public networks. The system also provides a single graphical user access interface to the out-of-band infrastructure, independent of physical interface, through any computer connected to the data network directly or to the system that embodies this invention through a modem connection. The system also provides a single encryption and user authentication model, integrated to other enterprise security mechanisms, to secure the management data and prevent unauthorized access to the management ports independent of the out-of-band physical media. The system also provides local incident correlation capabilities that are independent of a centralized network management system so that it is possible to automate the execution of pre-programmed actions in response to pre-programmed events. The system also provides integration between the out-of-band domain and the high-level network management systems so that data center management can be consolidated in one single system. The present invention comprises a system and method for securing, integrating, automating and consolidating out-of-band management independent of the physical and logical interfaces in use. The system includes a connection mechanism that supports at least two interfaces selected from the group consisting of: serial consoles, KVM ports, power circuits, sensors and controls, Telnet and SSH, Intelligent Platform Management Interface (IPMI), Integrated Lights Out (ILO), Advanced Lights Out Management (ALOM). Thus, in accordance with the invention, an out-of-band management system for computer networks is provided. The system comprises a plurality of network nodes manageable through a dedicated management interface other than the data transmission interfaces wherein the plurality of network nodes use at least two different types of management interfaces that generate management data. The system also has a management module, executing on a computer, that converts the different types of management interface management data into a common management data format and that communicates the common management data format to a network management system. The network management system further comprises a web server application, executing on a computer, that generates a graphical user interface based on the common management data format and a web-browser that permits a user to access the management module. In accordance with another aspect of the invention, an out-of-band network management method executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols is provided. Using the method, management data from the one or more management interfaces is received and the management data of the one or more management interfaces is converted into a common management data protocol. The common management data is communicated to a network management system that publishes a graphical user interface based on the common management data on a web server and permits access to the management interfaces using a web-browser. In accordance with another aspect of the invention, an out-of-band network management apparatus executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols is provided. The apparatus has management means, executing on a computer system, for converting the one or more management protocols into a common management data protocol and for communicating that common management data to a network management system. The network management system further comprising means, executing on a computer system, for publishing a graphical user interface based on the common management data and a web-browser utilized by the user to access the management application and the common management data. In accordance with yet another aspect of the invention, an out-of-band network management apparatus executing on a computer system for managing one or more network nodes with one or more management interfaces and management protocols is provided. The apparatus comprises a management application executing on a computer system that converts the one or more management protocols into a common management data protocol and communicates that common management data to a network management system. The network management system further comprises a web server application executing on a computer system that publishes a graphical user interface based on the common management data and a web-browser utilized by the user to access the management application and the common management data.
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20040629
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20090113
|
20060209
|
90320.0
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G06F15173
| 1
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ANYAN, BARBARA BURGESS
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SYSTEM AND METHOD FOR CONSOLIDATING, SECURING AND AUTOMATING OUT-OF-BAND ACCESS TO NODES IN A DATA NETWORK
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UNDISCOUNTED
| 0
|
ACCEPTED
|
G06F
| 2,004
|
|
10,881,372
|
ACCEPTED
|
Semiconductor device substrate with embedded capacitor
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A method for forming a semiconductor device including a DRAM cell structure comprising a silicon on insulator (SOI) substrate with an embedded capacitor structure including providing a substrate comprising an overlying first electrically insulating layer; forming a first electrically conductive layer on the first electrically insulating layer to form a first electrode; forming a capacitor dielectric layer on the first electrode; forming a second electrically conductive layer on the capacitor dielectric layer to form a second electrode; forming a second electrically insulating layer on the second electrode; and, forming a monocrystalline silicon layer over the second electrode to form an SOI substrate comprising a first capacitor structure.
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1. A method for forming a semiconductor device comprising a silicon on insulator (SOI) substrate with an embedded capacitor structure comprising the steps of: providing a substrate comprising an overlying first electrically insulating layer; forming a first electrically conductive layer on the first electrically insulating layer to form a first electrode; forming a capacitor dielectric layer on the first electrode; forming a second electrically conductive layer on the capacitor dielectric layer to form a second electrode; forming a second electrically insulating layer on the second electrode; and, forming a monocrystalline silicon layer over the second electrode to form an SOI substrate comprising a first capacitor structure. 2. The method of claim 1, further comprising the step of forming trenches through a thickness portion of the first electrically conductive layer prior to the step of forming a capacitor dielectric layer. 3. The method of claim 2, wherein the trenches comprise a trench spacing about equal to or less than a trench width. 4. The method of claim 2, wherein the trenches comprise a trench spacing greater than a trench width. 5. The method of claim 1, wherein the substrate comprises a silicon wafer. 6. The method of claim 1, wherein at least one of the first and second electrodes comprises one of a textured surface and a hemispherical grain surface (HSG) in contact with the capacitor dielectric layer. 7. The method of claim 1, wherein the monocrystalline silicon layer is formed comprising the steps of: bonding a major surface comprising a silicon wafer to the second electrically insulating layer surface; cleaving the silicon wafer to form the monocrystalline silicon layer; and, planarizing the cleaved surface. 8. The method of claim 1, wherein the capacitor dielectric layer is selected from the group consisting of oxides, nitrides, tantalum pentaoxide (Ta2O3), barium strontium titanate (BST), strontium titanate (SrTiO3), lead zirconate titanate (PZT), and combinations thereof. 9. The method of claim 1, wherein the first electrically insulating layer and second electrically insulating layer comprises silicon oxide. 10. The method of claim 1, further comprising the step of forming a word line, a bit line on the SOI substrate, and an electrical interconnect with the first capacitor structure. 11. The method of claim 9, further comprising the step of forming at least a second capacitor structure over the SOI substrate electrically wired in parallel with first capacitor structure. 12. The method of claim 11, wherein the second capacitor structure comprises one of a stacked or trench capacitor structure. 13. A method for forming a DRAM cell comprising a silicon on insulator (SOI) substrate with an embedded capacitor structure comprising the steps of: providing a substrate comprising an overlying first electrically insulating layer; forming a first electrically conductive layer on the first electrically insulating layer to form a first electrode; forming trenches through a thickness portion of the first electrically conductive layer; forming a capacitor dielectric layer on the first electrode; forming a second electrically conductive layer on the capacitor dielectric layer to form a second electrode; forming a second electrically insulating layer on the second electrode; forming a monocrystalline silicon layer over the second electrode to form an SOI substrate comprising a first capacitor structure; and, forming a word line and a bit line on the SOI substrate to form a DRAM cell. 14. The method of claim 13, wherein at least one of the first and second electrodes comprises one of a textured surface and a hemispherical grain surface (HSG) in contact with the capacitor dielectric layer. 15. The method of claim 13, wherein the DRAM cell further comprises an electrical interconnect to the first capacitor structure. 16. The method of claim 15, wherein the DRAM cell further comprises a second capacitor structure formed over the SOI substrate in electrical communication according to the electrical interconnect with the second electrode. 17. The method of claim 16, wherein the second capacitor structure comprises one of a stacked and trench capacitor structures formed in a dielectric insulating layer overlying the SOI substrate. 18. The method of claim 16, wherein the second capacitor structure comprises a trench. 19. The method of claim 18, wherein the trench comprises a bottom electrode in communication with the second electrode, an overlying second dielectric capacitor layer, and a top electrode. 20. The method of claim 13, wherein the substrate comprises a silicon wafer. 21. The method of claim 13, wherein the capacitor dielectric layer is selected from the group consisting of oxides, nitrides, tantalum pentaoxide (Ta2O3), barium strontium titanate (BST), strontium titanate (SrTiO3), lead zirconate titanate (PZT), and combinations thereof. 22. The method of claim 13, wherein the first electrically insulating layer and second electrically insulating layer comprise silicon oxide. 23. The method of claim 13, wherein the first and second electrodes are formed of a material selected from the group consisting of metals, metal nitrides, metal oxides, semiconductors, and polysilicon. 24. A DRAM cell comprising: an SOI substrate comprising a substrate; an overlying first electrically insulating layer. a first electrode on the substrate comprising trenches formed through a thickness thereof; a capacitor dielectric layer on the first electrode; a second electrode on the capacitor dielectric layer; an electrically insulating layer on the second electrode; a monocrystalline silicon layer on the electrically insulating layer; wherein a bit line and a word line are disposed on the SOI substrate. 25. The DRAM cell of claim 24, wherein the first electrode comprises trenches extending through a thickness portion of the first electrode. 26. The DRAM cell of claim 24, wherein at least one of the first and second electrodes comprises one of a textured surface and a hemispherical grain surface (HSG) in contact with the capacitor dielectric layer. 27. The DRAM cell of claim 24, wherein the DRAM cell further comprises an electrical interconnect to the first capacitor structure. 28. The DRAM cell of claim 27, further comprising a second capacitor structure disposed over the SOI substrate in electrical communication according to the electrical interconnect with the second electrode. 29. The DRAM cell of claim 24, wherein the second capacitor structure comprises one of a stacked and trench capacitor structure disposed in a dielectric insulating layer overlying the SOI substrate. 30. The DRAM cell of claim 24, wherein the second capacitor structure comprises a trench. 31. The DRAM cell of claim 30, wherein the trench comprises a bottom electrode in communication with the second electrode, an overlying second dielectric capacitor layer, and a top electrode. 32. The DRAM cell of claim 24, wherein the SOI substrate comprises a silicon wafer. 33. The DRAM cell of claim 24, wherein the capacitor dielectric layer is selected from the group consisting of oxides, nitrides, tantalum pentaoxide (Ta2O3), barium strontium titanate (BST), strontium titanate (SrTiO3), lead zirconate titanate (PZT), and combinations thereof. 34. The DRAM cell of claim 24, wherein the first electrically insulating layer and second electrically insulating layer comprise silicon oxide. 35. The DRAM cell of claim 24, wherein the first and second electrodes are formed of a material selected from the group consisting of metals, metal nitrides, metal oxides, semiconductors, and polysilicon. 36. An SOI substrate for forming a DRAM cell comprising: a substrate; an overying first electrically insulating layer. a first electrode on the substrate comprising trenches formed through a thickness thereof; a capacitor dielectric layer on the first electrode; a second electrode on the capacitor dielectric layer; an electrically insulating layer on the second electrode; and, a monocrystalline silicon layer on the electrically insulating layer. 37. The SOI substrate of claim 36, wherein at least one of the first and second electrodes comprises one of a textured surface and a hemispherical grain surface (HSG) in contact with the capacitor dielectric layer. 38. The SOI substrate of claim 36, wherein the capacitor dielectric layer is selected from the group consisting of oxides, nitrides, tantalum pentaoxide (Ta2O3), barium strontium titanate (BST), strontium titanate (SrTiO3), lead zirconate titanate (PZT), and combinations thereof. 39. The SOI substrate of claim 36, wherein the first electrically insulating layer and second electrically insulating layer comprise silicon oxide. 40. The SOI substrate of claim 36, wherein the first and second electrodes are formed of a material selected from the group consisting of metals, metal nitrides, metal oxides, semiconductors, and polysilicon.
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FIELD OF THE INVENTION This invention generally relates to microelectronic integrated circuit (IC) semiconductor device fabrication and more particularly to DRAM devices including a substrate with an embedded capacitor. BACKGROUND OF THE INVENTION Dynamic random access memory (DRAM) is a staple aspect of the main memory of PC systems. DRAM may be used as an embedded portion of an integrated circuit or be formed as an array of memory cells. Fir example, in memory cell arrays an MOS transistor and a capacitor make up a memory unit (cell) whereby word-lines are used to switch a pass transistor between an on and of state to connect the bit line to the capacitor or to isolate the capacitor. The bit line is used for both the read and write operations to the storage node of the capacitor. Generally, three types of DRAM memory cells are in use including planar capacitor DRAM cells, stack capacitor DRAM cells and trench capacitor DRAM cells. A key element of DRAM devices is the scaling down of feature sizes to produce a smaller memory cell and allow the formation of a higher density of memory cells. One challenge for increasing DRAM density is maintain the same cell capacitance as memory cell sizes are scaled down. Generally three approaches are available for doing this including increasing the dielectric constant of the capacitor dielectric, reducing the thickness of the capacitor dielectric, and increasing the area of the capacitor dielectric. Prior art processes general use silicon on insulator (SOI) technology requiring complex formation processes to form the capacitor architecture together with the MOS transistors and bit and word lines that make up an operating memory cell. As DRAM memory cell sizes decrease, the formation of trenches and electrode materials is increasingly difficult due to small etching process windows and the difficulty in handling advanced electrode and capacitor dielectric materials. Another problem with prior art approaches to producing DRAM devices is the inefficient use of active device area space, for example, in the substrate underlying the MOS transistor source and channel regions, frequently increasing the DRAM cell area by forming capacitors adjacent the bit and word lines and/or taking part of the drain area. There is therefore a continuing need in the semiconductor manufacturing art including the IC memory manufacturing art for improved DRAM cell architectures including capacitor architectures and method for forming the same to reliably increase a capacitor area while efficiently utilizing active area space. It is therefore an object of the invention to provide improved DRAM cell architectures including capacitor architectures and method for forming the same to reliably increase a capacitor area while efficiently utilizing active area space, while overcoming other shortcomings and deficiencies of the prior art. SUMMARY OF THE INVENTION To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention provides an embedded capacitor SOI substrate including a DRAM cell structure and method for forming the same. In a first embodiment, the method includes providing a substrate comprising an overlying first electrically insulating layer; forming a first electrically conductive layer on the first electrically insulating layer to form a first electrode; forming a capacitor dielectric layer on the first electrode; forming a second electrically conductive layer on the capacitor dielectric layer to form a second electrode; forming a second electrically insulating layer on the second electrode; and, forming a monocrystalline silicon layer over the second electrode to form an SOI substrate comprising a first capacitor structure. These and other embodiments, aspects and features of the invention will be better understood from a detailed description of the preferred embodiments of the invention which are further described below in conjunction with the accompanying Figures. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1E are cross sectional views of a portion of a and embedded capacitor SOI substrate at manufacturing stages according to an embodiment of the present invention. FIG. 2A is a cross sectional view of a DRAM memory cell structure according to an embodiment of the present invention using an embedded capacitor SOI substrate. FIG. 2B is a cross sectional view of a DRAM memory cell structure according to an embodiment of the present invention using an embedded capacitor SOI substrate. FIG. 3 is a process flow diagram including several embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1A, is shown a substrate 10, for example a semiconductor wafer such as silicon. An electrically insulating layer 12, for example an oxide such as silicon oxide is grown and/or deposited over the substrate 10 by conventional processes to a predetermined thickness. Referring to FIG. 1B, an electrically conductive material layer 14 is the formed over the electrically insulating layer 12 at a desired thickness to form a first capacitor electrode layer to a desired thickness. The first capacitor electrode layer may formed of any electrically conductive material including metals, metal oxides, metal nitrides, and metal oxynitrides as well as semiconductor materials such as doped or undoped polysilicon. The first capacitor electrode layer 14 is then patterned by conventional methods e.g., photoresist and/or a nitride hardmask, followed by a wet or dry etching process to form a series of spaced trench openings e.g., 16A through a thickness portion of the electrically conductive material layer 14. The first capacitor electrode layer 14 following trench formation may be etched to roughen or texture the surface of the first electrode to increase a contact surface area with a subsequently deposited capacitor dielectric, also referred to as hemispherical grain (HSG) surface. The trench opening widths e.g., A and spaces between trench openings e.g., B may have different or about the same widths with respect to one another, including having various groups of respective A and B widths at different portions of the process wafer. Referring to FIG. 1C, following forming of the trench openings e.g., 16A and removing resist and/or hardmask, a capacitor dielectric layer 18 is formed on the first capacitor electrode layer 14 by a conventional deposition process. The capacitor dielectric layer may be formed any high-K dielectric, preferably greater than about 10, more preferably greater than about 20, including oxides, nitrides, high-K dielectric materials, or combinations thereof. For example, the high-K materials may include tantalum pentaoxide (Ta2O3), barium strontium titanate (BST), strontium titanate (SrTiO3), lead zirconate titanate (PZT), or combinations thereof. The capacitor dielectric layer 18 is formed at a desired thickness to form a desired capacitance depending on the material and subsequent application of the capacitor, e.g., a DRAM structure. Referring to FIG. 1D, following formation of the capacitor dielectric layer 18, a second capacitor electrode (e.g., bottom electrode) layer 20 is formed on the capacitor dielectric layer and may be formed of the same or different material as the first capacitor electrode (e.g., top electrode) layer 14. Preferably, at least the second capacitor electrode includes a hemispherical grain (HSG) surface, for example formed by selective deposition of the second capacitor electrode layer 20, e.g., polysilicon, in contact with the capacitor dielectric layer 18. The second capacitor electrode layer 20 is then planarized, e.g., by a CMP process. An electrically insulating layer 22 is then formed on the second capacitor electrode layer 20. For example, the insulating layer 22 is an oxide layer formed by at least one of a thermal growth, chemical oxidation, plasma oxidation, and/or CVD oxide deposition process. Referring to FIG. 1E, a monocrystalline silicon layer 24 is then formed over the electrically insulating layer 22. For example, preferably, a second silicon wafer major surface either bare or having an oxide layer (not shown) is bonded to the electrically insulating layer 22. The second silicon wafer is then processed to form a relatively thin layer of monocrystalline silicon as an uppermost layer 24 sufficiently thick to form FET transistors thereon. For example, the second silicon wafer may be implanted with an ion such as hydrogen followed by room temperature bonding to the electrically insulating layer 22 followed by an annealing process at 400° C. to 600° C. to cleave the second silicon wafer at an the implant depth leaving a thin portion of the second silicon wafer as an uppermost monocrystalline silicon layer 24 thereby forming a silicon on insulator (SOI) substrate. The monocrystalline silicon layer 24 is then planarized by CMP to complete the formation of the SOI substrate including an embedded capacitor structure. Referring to FIG. 2A is shown a DRAM cell according to an embodiment of the present invention produced using the SOI substrate with the embedded capacitor structure. For example conventional processes are carried out to form shallow trench isolation (STI) structures 32A and 32B to electrically isolate the DRAM cell, followed by forming a conventional FET structure 34, e.g., a word line, including a gate dielectric 34A, a gate electrode 34B, spacers 34C and 34D as well as doped source and drain regions (not shown) formed in the silicon layer 24 adjacent the spacers. Electrically conductive interconnects e.g., a bit line 36 are formed e.g., by a damascene process including forming a dielectric insulating layer (not shown) over the FET structure followed by forming interconnect openings and backfilling with a conductive material to form a bit line 36 overlying a drain region. Conventional processes such as salicide formation over source and drain regions may be included in the FET formation process. In addition, an electrically conductive capacitor electrode contact e.g., 38 is formed by etching a contact opening through the silicon layer 24 and through the second electrically insulating layer 22 to contact the second capacitor electrode (e.g., bottom electrode) 20 on the source region side of the FET structure followed by backfilling with a conductive material. Advantageously, according to the present invention, conventional processes to form the FET structure and interconnect lines of the DRAM memory cell may be easily implemented in a second separate process flow using previously formed SOI substrates with the embedded capacitor structure, thereby avoiding process integration difficulties of forming the capacitor and the FET structures in a single process flow. In addition, the embedded capacitor structure efficiently uses space below the DRAM cell active area thereby allowing ready formation of scaled down Dram cell sizes. Referring to FIG. 2B, is shown a second DRAM cell according to an embodiment of the present invention produced using the SOI substrate with the embedded capacitor structure. In this embodiment, a second capacitor structure, preferably a stacked or trench capacitor structure is formed in electrical contact, preferably wired in parallel, with the embedded capacitor structure to form a stacked capacitor structure. For example, a trench 42 is formed in insulating layer 40, followed by forming a first capacitor dielectric layer 44A along the trench bottom and sidewalls. A first conductive material layer 46 is then formed on the capacitor dielectric material layer 44A to form a bottom capacitor electrode followed by forming a second capacitor dielectric material layer 44B on the bottom capacitor electrode 46, followed by forming a second conductive material layer 48 on the second capacitor dielectric material layer 44B to form a top electrode. Thus, an SOI substrate with an embedded capacitor structure has been presented including a method for forming the same. DRAM cell structures have been presented using the embedded capacitor SOI substrate. Advantageously, according to the present invention the embedded trench capacitor SOI substrate increases an available capacitance by at least about twice compared to prior art processes, advantageously maximizing capacitor surface area while efficiently using the substrate space under active areas for bit line, word line, and electrical contact formation. The embedded trench capacitor SOI substrate may advantageously be formed in a separate process flow thereby overcoming process integration issues in forming capacitors and DRAM cell structures in a single process flow. In addition, the quality of the performance of the embedded capacitor structure may be separately tested and verified prior to the bit line, word line, and electrical contact formation process flow, thereby improving DRAM cell yield, throughput, and device reliability. Moreover, a variety of DRAM cell structures including single and stacked capacitor structures with improved substrate area utilization may then be easily formed in a second process flow over the embedded trench capacitor SOI substrate thereby offering ready scalability. Referring to FIG. 3 is a process flow diagram including several embodiments of the present invention. In process 301, a substrate, e.g., wafer with an overlying first electrically insulating layer is provided. In process 303, a top capacitor electrode is formed on the first electrically insulating layer according to preferred embodiments. In process 305, a capacitor dielectric material layer is formed on the top capacitor electrode. In process 307, a bottom capacitor electrode is formed on the capacitor dielectric material layer. In process 309, a second electrically insulating layer is formed on the bottom electrode. In process 311 a monocrystalline silicon layer is formed on the second electrical insulating layer to form an SOI substrate with an embedded capacitor. In process 313 a DRAM cell including a bit line, a word line and a bottom electrode contact is formed over the SOI substrate. The preferred embodiments, aspects, and features of the invention having been described, it will be apparent to those skilled in the art that numerous variations, modifications, and substitutions may be made without departing from the spirit of the invention as disclosed and further claimed below.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Dynamic random access memory (DRAM) is a staple aspect of the main memory of PC systems. DRAM may be used as an embedded portion of an integrated circuit or be formed as an array of memory cells. Fir example, in memory cell arrays an MOS transistor and a capacitor make up a memory unit (cell) whereby word-lines are used to switch a pass transistor between an on and of state to connect the bit line to the capacitor or to isolate the capacitor. The bit line is used for both the read and write operations to the storage node of the capacitor. Generally, three types of DRAM memory cells are in use including planar capacitor DRAM cells, stack capacitor DRAM cells and trench capacitor DRAM cells. A key element of DRAM devices is the scaling down of feature sizes to produce a smaller memory cell and allow the formation of a higher density of memory cells. One challenge for increasing DRAM density is maintain the same cell capacitance as memory cell sizes are scaled down. Generally three approaches are available for doing this including increasing the dielectric constant of the capacitor dielectric, reducing the thickness of the capacitor dielectric, and increasing the area of the capacitor dielectric. Prior art processes general use silicon on insulator (SOI) technology requiring complex formation processes to form the capacitor architecture together with the MOS transistors and bit and word lines that make up an operating memory cell. As DRAM memory cell sizes decrease, the formation of trenches and electrode materials is increasingly difficult due to small etching process windows and the difficulty in handling advanced electrode and capacitor dielectric materials. Another problem with prior art approaches to producing DRAM devices is the inefficient use of active device area space, for example, in the substrate underlying the MOS transistor source and channel regions, frequently increasing the DRAM cell area by forming capacitors adjacent the bit and word lines and/or taking part of the drain area. There is therefore a continuing need in the semiconductor manufacturing art including the IC memory manufacturing art for improved DRAM cell architectures including capacitor architectures and method for forming the same to reliably increase a capacitor area while efficiently utilizing active area space. It is therefore an object of the invention to provide improved DRAM cell architectures including capacitor architectures and method for forming the same to reliably increase a capacitor area while efficiently utilizing active area space, while overcoming other shortcomings and deficiencies of the prior art.
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<SOH> SUMMARY OF THE INVENTION <EOH>To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention provides an embedded capacitor SOI substrate including a DRAM cell structure and method for forming the same. In a first embodiment, the method includes providing a substrate comprising an overlying first electrically insulating layer; forming a first electrically conductive layer on the first electrically insulating layer to form a first electrode; forming a capacitor dielectric layer on the first electrode; forming a second electrically conductive layer on the capacitor dielectric layer to form a second electrode; forming a second electrically insulating layer on the second electrode; and, forming a monocrystalline silicon layer over the second electrode to form an SOI substrate comprising a first capacitor structure. These and other embodiments, aspects and features of the invention will be better understood from a detailed description of the preferred embodiments of the invention which are further described below in conjunction with the accompanying Figures.
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20040630
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20070626
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20060105
|
97914.0
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H01L218234
| 0
|
MOVVA, AMAR
|
SEMICONDUCTOR DEVICE SUBSTRATE WITH EMBEDDED CAPACITOR
|
UNDISCOUNTED
| 0
|
ACCEPTED
|
H01L
| 2,004
|
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10,881,401
|
ACCEPTED
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Rare gas polarizer apparatus and magnetic resonance imaging system
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For the purpose of supplying a rare gas in a hyperpolarized state and an inspired material to a subject with quantifiability and without fail and conducting imaging, gaseous xenon in a hyperpolarized state in a gas bag and an inspired material such as oxygen are supplied to a mask section 210 in a closed state, and a positive or negative pressure in the internal space of the mask section 210 during expiration or inspiration of a subject 1 is detected at a diaphragm 220, and discharge from the internal space or intake of xenon and the inspired material such as oxygen to the internal space is conducted based on the detection; and therefore, gaseous xenon in a hyperpolarized state is prevented from leaking to the outer air before being inhaled by the subject 1 and is supplied at a generally constant flow rate and with high quantifiability, and in addition, the inspired material such as oxygen is supplied to the subject 1 without fail, achieving high safety.
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1. A rare gas polarizer apparatus comprising: a polarizing section for bringing a rare gas contained in a mixed gas to a hyperpolarized state; an extracting section for sublimating said rare gas from said mixed gas, extracting said rare gas as a solid, and vaporizing said extracted solid rare gas; and a supplying section for mixing said vaporized rare gas with an inspired material, and supplying said gas to a mask section closed against the outer air covering the respiratory organs of the subject. 2. The rare gas polarizer apparatus of claim 1, wherein said inspired material is oxygen or air containing oxygen. 3. The rare gas polarizer apparatus of claim 2, wherein said mask section comprises a diaphragm that is displaced synchronously with respiration of said subject. 4. The rare gas polarizer apparatus of claim 3, wherein said mask section comprises an on-off type intake valve for taking in said vaporized rare gas and said inspired material. 5. The rare gas polarizer apparatus of claim 4, wherein said intake valve comprises regulating section for regulating the amount of intake of said rare gas and said inspired material. 6. The rare gas polarizer apparatus of claim 4, wherein said intake valve comprises a stopper at an intake vent for said inspired material for preventing said intake vent from completely closing. 7. The rare gas polarizer apparatus of claim 1, wherein said mask section comprises an on-off type exhaust valve for discharging an expired material from said subject to said outer air. 8. The rare gas polarizer apparatus of claim 4, wherein said supplying section opens said intake valve in response to displacement of said diaphragm in synchronism with inspiration of said subject, and closes said intake valve in response to displacement of said diaphragm in synchronism with expiration of said subject. 9. The rare gas polarizer apparatus of claim 8, wherein said supplying section closes said exhaust valve synchronously with inspiration of said subject, and opens said exhaust valve synchronously with expiration of said subject. 10. The rare gas polarizer apparatus of claim 3, wherein said diaphragm comprises a detection sensor for detecting said displacement. 11. The rare gas polarizer apparatus of claim 1, wherein said supplying section comprises a flowmeter for measuring the flow rate of said vaporized rare gas. 12. A magnetic resonance imaging system comprising: a rare gas polarizer apparatus for supplying a rare gas in a hyperpolarized state to a subject, and a magnetic resonance imaging apparatus for acquiring magnetic resonance information on said subject inhaling said rare gas, said magnetic resonance imaging system characterized in that: said rare gas polarizer apparatus has supplying section for supplying said rare gas mixed with an inspired material to a mask section closed against the outer air covering the respiratory organs of said subject; said supplying section has a detection sensor for detecting said respiration; and said magnetic resonance imaging apparatus has a control processing section for conducting said acquisition or optimization of parameters for said acquisition based on respiration information from said detection sensor. 13. The magnetic resonance imaging system of claim 12, wherein said control processing section conducts said acquisition synchronously with the inspiration or expiration indicated in said respiration information. 14. The magnetic resonance imaging system of claim 13, wherein said control processing section conducts said acquisition after an additional lag time from said synchronization. 15. The magnetic resonance imaging system of claim 12, wherein said control processing section counts the number of times of respiration from said respiration information and conducts said optimization on parameters based on said number of times of respiration. 16. The magnetic resonance imaging system of claim 15, wherein said parameters include the gain of an amplifier for use in acquiring said magnetic resonance information. 17. The magnetic resonance imaging system of claim 12, wherein said supplying section further comprises a flowmeter for measuring the flow rate of said rare gas. 18. The magnetic resonance imaging system of claim 17, wherein said control processing section conducts said optimization of parameters based on flow rate information from said flowmeter.
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BACKGROUND OF THE INVENTION The present invention relates to a rare gas polarizer apparatus and a magnetic resonance imaging system for producing a rare gas in a hyperpolarized state, and conducting imaging using the rare gas. In recent years, a magnetic resonance image is acquired with high sensitivity with a rare gas isotope such as xenon (Xe), helium (He) etc. in a hyperpolarized state absorbed in a subject by inhalation or injection. To bring the rare gas to a hyperpolarized state, a rare gas polarizer apparatus is employed. The rare gas polarizer apparatus brings a rare gas isotope to a hyperpolarized state in a high temperature cell, and then solidifies only the rare gas in a hyperpolarized state by sublimation of the rare gas in a thermostatic bath containing liquid nitrogen under a high magnetic field environment to extract only the rare gas. The solidified rare gas is then vaporized by warming, and inhaled by the subject (for example, see Patent Document 1). At that time, the vaporized rare gas in a hyperpolarized state is accumulated in a gas bag, vial or the like, and then inhaled by the subject from the outlet of the bag or vial. Patent Document 1 Japanese Patent Publication No. 2000-507688 (Pages 7-19, FIG. 1). In the conventional technique, however, the amounts of the rare gas and an inspired material such as oxygen inhaled by the subject are indefinite. Specifically, the subject's inhalation of the rare gas from the outlet of the gas bag or vial is done in various ways different from subject to subject, and also some of the rare gas may leak to the outer air without being inhaled by the subject; therefore, the amounts of the rare gas and the inspired material such as oxygen inhaled are different from examination to examination. Especially, when the subject inhales, if only the gas contained in the gas bag or vial is inhaled, the inspired material such as oxygen becomes deficient, leading to the possibility of loss of consciousness of the subject. Moreover, the fact that the amount of the inhaled rare gas in a hyperpolarized state is indefinite may hamper quantification of magnetic resonance information such as acquired tomographic image information. It is therefore important to find a way to implement a rare gas polarizer apparatus and a magnetic resonance imaging system that supply a rare gas in a hyperpolarized state and an inspired material to the subject with quantifiability and without fail to conduct imaging. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rare gas polarizer apparatus and a magnetic resonance imaging system that supply a rare gas in a hyperpolarized state and an inspired material to a subject with quantifiability and without fail to conduct imaging. To solve the aforementioned problem and attain the object, a rare gas polarizer apparatus in accordance with the invention of a first aspect is characterized in comprising: a polarizing section for bringing a rare gas contained in a mixed gas to a hyperpolarized state; an extracting section for sublimating said rare gas from said mixed gas, extracting said rare gas as a solid, and vaporizing said extracted solid rare gas; and supplying means for mixing said vaporized rare gas with an inspired material, and supplying said gas to a mask section closed against the outer air covering the respiratory organs of the subject. According to the invention of the first aspect, the polarizing section brings a rare gas contained in a mixed gas to a hyperpolarized state, the extracting section sublimates the rare gas from the mixed gas, extracts the rare gas as a solid, and vaporizes the extracted solid rare gas, and the supplying means mixes the vaporized rare gas with an inspired material, and supplies the gas to a mask section closed against the outer air covering the respiratory organs of the subject; and therefore, the rare gas in a hyperpolarized state is prevented from leaking to the outer air, and the rare gas, along with the inspired material including oxygen etc., is inhaled by the subject without fail, so that a rare gas in a hyperpolarized state can be supplied to the subject with quantifiability and safety. A rare gas polarizer apparatus in accordance with the invention of a second aspect is characterized in that: said inspired material is oxygen or air containing oxygen. According to the invention of the second aspect, even though the closed mask section is employed, the subject can continue respiration. A rare gas polarizer apparatus in accordance with the invention of a third aspect is characterized in that: said mask section comprises a diaphragm that is displaced synchronously with respiration of said subject. According to the invention of the third aspect, a pressure change inside the mask section can be detected. A rare gas polarizer apparatus in accordance with the invention of a fourth aspect is characterized in that: said mask section comprises an on-off type intake valve for taking in said vaporized rare gas and said inspired material. According to the invention of the fourth aspect, since the mask section takes in the vaporized rare gas and inspired material through an on-off type intake valve, the intake of the vaporized rare gas and inspired material can be controlled. A rare gas polarizer apparatus in accordance with the invention of a fifth aspect is characterized in that: said intake valve comprises regulating means for regulating the amount of intake of said rare gas and said inspired material. According to the invention of the fifth aspect, since the intake valve regulates the amount of intake of the rare gas and inspired material by the regulating means, finer regulation on the mix ratio between the rare gas and inspired material, for example, can be achieved. A rare gas polarizer apparatus in accordance with the invention of a sixth aspect is characterized in that: said intake valve comprises a stopper at an intake vent for said inspired material for preventing said intake vent from completely closing. According to the invention of the sixth aspect, since the intake valve prevents the intake vent for the inspired material from completely closing by a stopper at the intake vent, the inspired material supplied to the subject is protected against stopping in some abnormal condition. A rare gas polarizer apparatus in accordance with the invention of a seventh aspect is characterized in that: said mask section comprises an on-off type exhaust valve for discharging an expired material from said subject to said outer air. According to the invention of the seventh aspect, since the mask section exhausts an expired material from the subject to the outer air through an on-off type exhaust valve, the expired material such as carbon dioxide can be discharged without fail. A rare gas polarizer apparatus in accordance with the invention of an eighth aspect is characterized in that: said supplying means opens said intake valve in response to displacement of said diaphragm in synchronism with inspiration of said subject, and closes said intake valve in response to displacement of said diaphragm in synchronism with expiration of said subject. According to the invention of the eighth aspect, the rare gas and inspired material can be taken in with inspiration and the intake can be stopped by expiration, synchronously with the displacement of the diaphragm. A rare gas polarizer apparatus in accordance with the invention of a ninth aspect is characterized in that: said supplying means closes said exhaust valve synchronously with inspiration of said subject, and opens said exhaust valve synchronously with expiration of said subject. According to the invention of the ninth aspect, when the intake valve is open the exhaust valve is closed, and when the intake valve is closed the exhaust valve is opened, so that intake of the rare gas and discharge can be achieved efficiently and without waste. A rare gas polarizer apparatus in accordance with the invention of a tenth aspect is characterized in that: said diaphragm comprises a detection sensor for detecting said displacement. According to the invention of the tenth aspect, since the diaphragm detects the displacement by a detection sensor, respiration information can be obtained as an electric signal. A rare gas polarizer apparatus in accordance with the invention of an eleventh aspect is characterized in that: said supplying means comprises a flowmeter for measuring the flow rate of said vaporized rare gas. According to the invention of the eleventh aspect, since the supplying means measures the flow rate of the vaporized rare gas by a flowmeter, more detailed information on the amount of the inhaled rare gas can be obtained. A magnetic resonance imaging system in accordance with the invention of a twelfth aspect comprises: a rare gas polarizer apparatus for supplying a rare gas in a hyperpolarized state to a subject, and a magnetic resonance imaging apparatus for acquiring magnetic resonance information on said subject inhaling said rare gas, and said magnetic resonance imaging system is characterized in that: said rare gas polarizer apparatus has supplying means for supplying said rare gas mixed with an inspired material to a mask section closed against the outer air covering the respiratory organs of said subject; said supplying means has a detection sensor for detecting said respiration; and said magnetic resonance imaging apparatus has a control processing section for conducting said acquisition or optimization of parameters for said acquisition based on respiration information from said detection sensor. According to the invention of the twelfth aspect, in the rare gas polarizer apparatus, the supplying means supplies a rare gas mixed with an inspired material to a mask section closed against the outer air covering the respiratory organs of the subject; in the supplying means, the detection sensor detects the respiration; and in the magnetic resonance imaging apparatus, the control processing section conducts the acquisition or optimization of parameters for the acquisition based on respiration information from the detection sensor; therefore, quantifiability of the rare gas in a hyperpolarized state inhaled by the subject and respiration information including the inhalation allows for quantitative analysis of magnetic resonance information such as tomographic image information on the subject, and moreover, optimization of parameters including the gain or band width in acquiring the magnetic resonance information can be achieved. A magnetic resonance imaging system in accordance with the invention of a thirteenth aspect is characterized in that: said control processing section conducts said acquisition synchronously with the inspiration or expiration indicated in said respiration information. According to the invention of the thirteenth aspect, when tomographic image information on the subject is acquired, artifacts can be reduced; more generally, when magnetic resonance information is acquired, stable information can be obtained. A magnetic resonance imaging system in accordance with the invention of a fourteenth aspect is characterized in that: said control processing section conducts said acquisition after an additional lag time from said synchronization. According to the invention of the fourteenth aspect, by changing the lag time, data can be acquired in any phase of respiration. A magnetic resonance imaging system in accordance with the invention of a fifteenth aspect is characterized in that: said control processing section counts the number of times of respiration from said respiration information and conducts said optimization on parameters based on said number of times of respiration. According to the invention of the fifteenth aspect, information on the speed of motion of the subject based on the number of times of respiration of the subject allows parameters such as the band width and number of data acquisitions to be set for artifact reduction or high SNR. A magnetic resonance imaging system in accordance with the invention of a sixteenth aspect is characterized in that: said parameters include the gain of an amplifier for use in acquiring said magnetic resonance information. According to the invention of the sixteenth aspect, a gain when the rare gas in a hyperpolarized state is inhaled can be optimized from a gain in a prescan. A magnetic resonance imaging system in accordance with the invention of a seventeenth aspect is characterized in that: said supplying means further comprises a flowmeter for measuring the flow rate of said rare gas. According to the invention of the seventeenth aspect, since the supplying means measures the flow rate of the rare gas by a flowmeter, more detailed information on the amount of the inhaled rare gas can be obtained. A magnetic resonance imaging system in accordance with the invention of a seventeenth aspect is characterized in that: said control processing section conducts said optimization of parameters based on flow rate information from said flowmeter. According to the invention of the eighteenth aspect, since detailed information on the amount of the rare gas inhaled by the subject is obtained, adjustment of the gain of the amplifier and other-such tuning can be more finely conducted based on the detailed information. According to the present invention, the polarizing section brings a rare gas contained in a mixed gas to a hyperpolarized state, the extracting section sublimates the rare gas from the mixed gas, extracts the rare gas as a solid, and vaporizes the extracted solid rare gas, and the supplying means mixes the vaporized rare gas with an inspired material, and supplies the gas to a mask section closed against the outer air covering the respiratory organs of the subject; and therefore, the rare gas in a hyperpolarized state is prevented from leaking to the outer air, and the rare gas, along with the inspired material including oxygen etc., is inhaled by the subject without fail, so that a rare gas in a hyperpolarized state can be supplied to the subject with quantifiability and safety. Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the overall configuration of a magnetic resonance imaging system. FIG. 2 is a block diagram showing the configuration of a rare gas polarizer apparatus in Embodiment 1. FIG. 3 is a diagram showing the configuration of a mask section in Embodiment 1. FIG. 4 is a diagram showing the operation of the mask section in Embodiment 1. FIG. 5 is a diagram showing a respiration signal and magnetic resonance information in Embodiment 2. FIG. 6 is a diagram showing the configuration of supplying means in Embodiment 3. DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of a rare gas polarizer apparatus and a magnetic resonance imaging system in accordance with the present invention will now be described with reference to the accompanying drawings. EMBODIMENT 1 First, the overall configuration of a magnetic resonance imaging system in accordance with Embodiment 1 will be described. FIG. 1 is a block diagram showing the overall configuration of the magnetic resonance imaging system of the present invention. The magnetic resonance imaging system comprises a magnetic resonance imaging apparatus 200 and a rare gas polarizer apparatus 3. The magnetic resonance imaging apparatus 200 comprises a magnet system 700, a data collecting section 750, a transmission driving section 740, a gradient driving section 730 and a control processing section 800. The control processing section 800 comprises a scan controller section 760, a data management section 770, a display section 780 and an operating section 790. The magnet system 700 has a main magnetic field coil section 702, a gradient coil section 706, a transmission coil section 708 and an RF coil section 710. These coil sections have a generally cylindrical shape and are concentrically disposed with respect to one another. A subject 1 rested on a cradle 720 is carried into and out of a generally cylindrical internal space (bore) of the magnet system by carrier means (not shown). In such a configuration, control information is input from the operating section 790 to the data management section 770, and the control information is transferred to the scan controller section 760, then from the scan controller section 760 to the data collecting section 750, and output to the transmission driving section 740 and gradient driving section 730. The main magnetic field coil section 702 generates a static magnetic field in the internal space of the magnet system 700. The direction of the static magnetic field is generally parallel to the direction of the body axis of the subject 1. That is, a magnetic field generally called a horizontal magnetic field is generated. The main magnetic field coil section 702 is made using a superconductive coil, for example; however, it is not limited to the superconductive coil but may be made using a normal conductive coil or the like. The gradient coil section 706 generates three gradient magnetic fields for imparting gradients to the static magnetic field intensity along three mutually orthogonal axes, i.e., a slice axis, a phase axis and a frequency axis. The transmission coil section 708 generates a radio frequency magnetic field for exciting magnetic resonance within the subject 1 in the static magnetic field space. The RF coil section 710 is placed on the cradle 720, and is positioned in the central portion of the magnet system 700 along with the subject 1. The RF coil section 710 receives magnetic resonance signals excited by the transmission coil section 708 within the subject 1. The gradient coil section 706 is connected to the gradient driving section 730. The gradient driving section 730 transmits a driving signal to the gradient coil section 706 to generate the gradient magnetic fields. The gradient driving section 730 has three driving circuits (not shown) corresponding to the three gradient coils in the gradient coil section 706. The transmission coil section 708 is connected to the transmission driving section 740. The transmission driving section 740 supplies a driving signal to the transmission coil section 708 to transmit an RF pulse, and the transmission coil section 708 then generates the RF magnetic field in the central portion of the magnet system 700 in response to the transmitted RF pulse to bring the subject 1 to a magnetic resonance excited state. The RF coil section 710 is connected to the data collecting section 750. The data collecting section 750 takes in a received signal received at the RF coil section 710 by sampling it, and collects the signal as digital data. The gradient driving section 730, transmission driving section 740 and data collecting section 750 are connected to the scan controller section 760. The scan controller section 760 serving as a reception control section controls the gradient driving section 730, transmission driving section 740 and data collecting section 750 to conduct imaging. The output of the data collecting section 750 is connected to the data management section 770. Data collected by the data collecting section 750 is input to the data management section 770. The data management section 770 is made using, for example, a computer, and has a memory (not shown). The memory stores programs and several kinds of data for the data management section 770. The data management section 770 is connected to the scan controller section 760. The data management section 770 is upstream of the scan controller section 760 and controls it. Acquisition of magnetic resonance information including tomographic image information in the present apparatus is implemented by executing at the scan controller section 760 a pulse sequence that is a program stored in the memory in the data management section 770. The pulse sequence contains a sequence of all of control information output to the gradient driving section 730, transmission driving section 740 and data collecting section 750. The data management section 770 stores the data collected by the data collecting section 750 into the memory. In the memory, a data space is thus formed. The data space forms a two-dimensional Fourier space. The data management section 770 performs two-dimensional inverse Fourier transformation on the data in the two-dimensional Fourier space to reconstruct an image of the subject 1. The data management section 770 is connected to the display section 780 and operating section 790. The display section 780 comprises a graphic display such as an LCD (liquid crystal display). The operating section 790 comprises a keyboard provided with a pointing device, for example. The display section 780 displays the reconstructed image and several kinds of information output from the data management section 770. The operating section 790 is operated by a human operator, and inputs several kinds of instructions and information to the data management section 770. The operator interactively operates the present apparatus via the display section 780 and operating section 790. The RF coil section 710 comprises a birdcage coil, for example, for receiving a magnetic resonance signal excited within the subject 1. The rare gas polarizer apparatus 3 supplies a hyperpolarized rare gas, for example, isotope xenon (Xe), to the subject 1. The hyperpolarized state will now be briefly described. Isotope rubidium (Rb) or xenon that is a rare gas has a nuclear magnetic moment, and when a static magnetic field is applied, the gas is distributed among different energy states. In a normal temperature equilibrium state, isotope rubidium or xenon is distributed generally equally among all the states. On the contrary, a state in which much of isotope rubidium or xenon is disproportionally present in a certain state is called a hyperpolarized state. In the hyperpolarized state, more of isotope rubidium or xenon can be brought to an excited state of a magnetic resonance phenomenon, thereby improving signal sensitivity. The rare gas polarizer apparatus 3 supplies gaseous xenon in a hyperpolarized state to the subject 1 via a mask section 210 attached to the subject 1. The subject 1 inhales the xenon, and takes it into the blood via the lungs. Then, magnetic resonance imaging can be conducted on the subject 1 to image xenon with high sensitivity. Next, the configuration of the rare gas polarizer apparatus 3 will be described in detail with reference to FIG. 2. FIG. 2 is a diagram showing a configuration of several blocks in the rare gas polarizer apparatus 3 and cross sections of the blocks. The rare gas polarizer apparatus 3 comprises a gas supply section 50, a polarizing section 10, a trap section 20, an extracting section 30, a rare gas collecting section 60, supplying means 4, a pipe 40 for connecting the polarizing section 10, trap section 20 and extracting section 30, a glass tube 70 for connecting the extracting section 30 and rare gas collecting section 60, and a tube 266 for connecting the rare gas collecting section 60 and supplying means 4. In such a configuration, a static magnetic field B1 and a static magnetic field B2 are applied to the polarizing section 10 and extracting section 30, which static magnetic fields are generated by a permanent magnet (not shown), for example. The gas supply section 50 is comprised of an on-off valve 520 for regulating supply of isotope rubidium from the outside, a tank 510, and a metal pipe for supplying a mixed gas to the polarizing section 10. The tank 510 stores a mixed gas of xenon isotope, nitrogen and helium (He), approximately in a proportion of 1%, 1%, 98%, compressed under a high pressure. The mixed gas is mixed with isotope rubidium at the outlet of the tank 510, and then led to the polarizing section 10. The polarizing section 10 comprises a cell 110, an oven 100 and a valve 120. The oven 100 contains therein the cell 110, and places the cell 110 under a high temperature of about 200° C. The polarizing section 10 is irradiated with a circularly polarized laser light. The laser light is generated by a laser diode array (not shown), for example, and has a wavelength determined by an alkali metal contained in the mixed gas. For example, for rubidium, the wavelength is about 795 nm (nanometers). The oven 100 and cell 110 have respective glass windows for letting the laser light into the cell 110. The valve 120 is an on-off valve, and the mixed gas produced at the gas supply section 50 is led into the cell 110 by opening the valve 120. The cell 110 is comprised of an internal cavity for making the mixed gas interact with the circularly polarized laser, and an interior wall and an exterior wall surrounding the internal cavity. The interior wall is made of glass, and the exterior wall is made of a stainless steel, for example. The exterior wall of the cell 110 on the side surface exposed to the circularly polarized laser is provided with a window 130 of refractory glass. The circularly polarized laser light passing through the window of the oven 100 and the window 130 enters the cell 110, and interacts with the mixed gas. The pipe 40 carries the mixed gas in the cell 110 to the extracting section 30 through the trap section 20. The trap section 20 has a cryostat 21 on an interior wall of glass of the pipe 40. The cryostat 21 is a cooling pipe carrying water wound around the interior wall of the pipe 40, for example. The mixed gas within the interior wall is thus cooled, and gaseous rubidium in the mixed gas is liquefied and solidified for removal. The extracting section 30 comprises an accumulator 300, a thermostatic bath 310, a liquid nitrogen 330, a lift 320, a needle valve 190 and valves 140-160. The accumulator 300 is supported by a supporting implement (not shown), and the position of the accumulator 300 relative to the thermostatic bath 310 can be arbitrarily set by the operator. The accumulator 300 is supplied with the mixed gas from the trap section 20 through the pipe 40. The vessel of the accumulator 300 has an interior wall of glass and an exterior wall of metal, similarly to the cell 110 and pipe 40. The accumulator 300 and the pipe 40 are separable, and only the glass tube portion of the interior wall of the pipe 40 extends as an inlet to the accumulator 300. The glass tube portion has a length such that when the accumulator 300 is attached with the pipe 40, the glass tube portion reaches the bottom of the accumulator 300, and thus the mixed gas in the pipe 40 is sprayed directly onto the bottom of the accumulator 300. Moreover, the accumulator 300 has in its upper portion an exhaust for discarding the remaining gas, and a connection port to the rare gas collecting section 60. The exhaust is attached with the valve 160 of an on-off type and the needle valve 190 via a metal tube, for example. The needle valve 190 has a partition provided with a needle hole for separating an inlet and an outlet. The accmulator 300 can thus be kept at a high pressure at the inlet side of the needle valve 190 and at an atmospheric pressure at the outlet side after opening the valve 160. The thermostatic bath 310 comprises a Dewar vessel, for example, and stores therein liquid nitrogen 330 for cooling the accumulator 300. Moreover, the thermostatic bath 310 is mounted on the lift 320 so that when the lift 320 is moved up, the accumulator 300 is immersed in the liquid nitrogen 330, and when the lift 320 is moved down, the accumulator 300 and liquid nitrogen 330 are separated. The rare gas collecting section 60 is connected with the accumulator 300 via the valve 150 and glass tube 70, and the section 60 comprises a gas bag 600, and on-off valves 170 and 180. The gas bag 600 is removable from the on-off valve 170, and is used when extracted gaseous xenon in a hyperpolarized state is inhaled by the subject. The supplying means 4 comprises the mask section 210, a tube 272, a tank 262 and a valve 180. The supplying means 4 is supplied with the rare gas from the gas bag 600 via the tube 266, and it in turn supplies the rare gas to the mask section 210. The tank 262 stores therein an inspired material containing air, oxygen gas or the like, and supplies the inspired material to the mask section 210 by opening the valve 280. It should be noted that the tube 272 is preferably made of a material other than metal so that it will not cause depolarization. FIG. 3 is a diagram of the mask section 210 showing its use and detailed configuration. FIG. 3(A) shows the mask section 210 attached to the subject 1. The mask section 210 is attached to the head of the subject 1 to cover the respiratory organs, i.e., the nose and mouse, of the subject 1 by a belt or the like. FIG. 3(B) shows the mask section 210 attached to the subject 1 in cross section. The mask section 210 comprises a side wall 270, a diaphragm 220, a sponge 230, valves 250 and 260, regulating means 259, a movable lever 240 and a detection sensor 290. The side wall 270 and diaphragm 220 have a bowl-like structure with a bottom of the diaphragm 220, and an open side opposite to the diaphragm 220 is in close contact with the face of the subject 1 including the nose and mouse. The open side of the side wall 270 is provided with the sponge 230 to improve closeness with the face of the subject 1. The internal space surrounded by the side wall 270, diaphragm 220 and face of the subject 1 is thus closed against the outer air. The material used for the side wall 270 is a light weight and deformation-proof one such as a plastic, and the material used for the diaphragm 220 is an elastic one such as a rubber sheet. Thus, as respiration of the subject 1 causes the internal space of the mask section 210 to alternate between positive and negative pressures relative to the outer air, the diaphragm 220 deforms in response to the positive and negative pressures. The side wall 270 is attached with the valve 250 and tube 266. The valve 250 serving as an exhaust valve is placed on the side wall 270 in a hole running from the internal space to the outer air, on the side of the outer air, and is in close contact with the side wall 270 from the side of the outer air by a spring 251. The tubes 266 and 272 are led from a hole running through the side wall 270 into the internal space via the regulating means 259. The side wall 270 is provided with a stopper 261, a valve 260 serving as an intake valve, and a movable lever 240 at the outlets of the tubes 266 and 272 to the internal space. The regulating means 259 is a control valve for controlling the in-tube flow rate of the tubes 266 and 272, and controls the mix ratio or absolute amounts of the rare gas and inspired material by the valve set at the intermediate state between open and close. The movable lever 240 moves the valve 260 serving as an intake valve in response to deformation of the diaphragm 220, and opens and closes the outlets of the tubes 266 and 272 to the internal space. The movable lever 240 is a V-shaped lever having a center of rotation at an intersection of two branches fixed on the side wall 270, and one of the two branches extending from the center of rotation is in contact with the surface of the diaphragm 220, and the other forms a surface to which the valve 260 is attached. The stopper 261 is placed between the valve 260 and outlet of the tube 272 to the internal space. The stopper 261 is kept at a slightly open state so that the inspired material such as oxygen is not cut off when the valve 260 closes the outlet of the tube 272. The subject 1 is thus protected against oxygen deficit in some abnormal condition. The diaphragm 220 is provided with the detection sensor 290. For the detection sensor 290, a distortion sensor such as a strain gauge may be used. The detection sensor 290 is connected to the scan controller section 760 via wiring (not shown), and an electric signal in synchronism with respiration of the subject 1 is transmitted to the scan controller section 760. Now the operation of the rare gas polarizer apparatus 3 and supplying means 4 in accordance with the present invention will be described. The operation of extracting isotope xenon in a hyperpolarized state at the accumulator 300 will first be briefly described. In conducting the extracting operation, the lift 320 is moved up to immerse the accumulator 300 in the liquid nitrogen 330, water is run into the cryostat 21 in the trap section 20 to bring the trap section 20 into an operating state, a circularly polarized laser is emitted toward the cell 110, the internal space of the oven 100 containing the cell 110 is brought to a temperature of about 200° C., a static magnetic field B1 of about 10 mT (Tesla) is applied to the polarizing section 10, and a static magnetic field B2 of about 0.2 T is applied to the extracting section 30. Then, the valves 520, 120, 140 and 160 are opened, and the valve 150 is closed. The mixed gas containing isotope rubidium produced at the gas supply section 50 is thus led into the cell 110. In the cell 110, isotope rubidium in the mixed gas absorbs the irradiated circularly polarized laser and is brought to a hyperpolarized state in which much of the rubidium isotope is at a high energy state. Then, the rubidium isotope in a hyperpolarized state transfers the hyperpolarized state to isotope xenon in the mixed gas by a phenomenon known as spin exchange transfer. The isotope xenon is thus brought to a hyperpolarized state in which much of the isotope xenon is at a high energy state. Thereafter, the mixed gas in the cell 110 is led to the trap section 20, where the cryostat 21 lowers the temperature of the mixed gas to remove the rubidium isotope by liquefaction or solidification. The mixed gas at the trap section 20 is then led into the accumulator 300 via the pipe 40. The mixed gas is sprayed directly onto the bottom of the accumulator 300 via the extension tube of the pipe 40. Since the bottom of the accumulator 300 is immersed in the liquid nitrogen 330 in the thermostatic bath 310 and is at about the liquid nitrogen temperature, the isotope xenon in the mixed gas sprayed there solidifies by sublimation into xenon ice. The other components in the mixed gas, i.e., helium gas and nitrogen gas, do not solidify, and are discarded from the accumulator 300 via the needle valve 190. Such a process continuously occurs while supplying the mixed gas from the tank 510 to accumulate xenon ice. Next, the operation of taking out xenon in a hyperpolarized state accumulated in the accumulator 300 to the gas bag 600 will be described. In conducting the take-out operation, the valves 520, 120, 140, 160 and 180 are closed, the valves 150 and 170 are open, the lift 320 is moved down, and the liquid nitrogen 330 in the thermostatic bath 310 is not in contact with the accumulator 300. Since the accumulator 300 is not in contact with the liquid nitrogen 330, it assumes a high temperature state. At that time, xenon ice in a hyperpolarized state present at the bottom of the accumulator 300 vaporizes by sublimation, and the vaporized isotope xenon is led from the valve 150 into the gas bag 600 via the glass tube, and accumulated there. This condition is maintained until the xenon ice present at the bottom of the accumulator 300 is spent. The xenon in a hyperpolarized state accumulated in the gas bag 600 is then supplied to the mask section 210 attached to the subject 1. At that time, the valve 150 is closed, and the valves 170 and 180 are opened. Thus, the gaseous xenon in a hyperpolarized state in the gas bag 600 is gradually carried to the mask section 210. Moreover, the valve 280 of the tank 262 is opened, so that the inspired material such as oxygen contained in the tank 262 is simultaneously led to the mask section 210. The amounts of the xenon and inspired material such as oxygen led to the mask section 210 are regulated by the regulating means 259. Next, the operation of the mask section 210 when the subject 1 respires will be described with reference to FIG. 4. FIG. 4 is a diagram showing the subject 1 attached with the mask section 210 in cross section. Respiration of the subject 1 is divided into an inspiring state in which the air is taken into the lungs, and an expiring state in which the air is discharged from the lungs. FIG. 4(A) is a diagram showing the operation of the mask section 210 when respiration of the subject 1 is in an inspiring state. The internal space of the mask section 210 is at a negative pressure relative to the outer air because of inspiration of the subject 1. Thus, the diaphragm 220 deforms to be pushed toward the subject 1. At that time, the movable lever 240 fixed at the side wall 270 rotates synchronously with the deformation of the diaphragm 220, and opens the valve 260. While the inspiring state is maintained, gaseous xenon in a hyperpolarized state and the inspired material such as oxygen are supplied from the open valve 260 at a generally constant flow rate. The valve 250 closes by being pushed from the outside against the side wall 270 with the aid of the effect of the spring 251 because the internal space is at a negative pressure relative to the outer air. Moreover, since the internal space of the mask section 210 at that time has a small volume relative to the amount of one cycle of inspiration of the subject 1, the rare gas and inspired material containing oxygen and the like supplied from the valve 260 are largely inhaled by the subject 1. Therefore, the rare gas supplied from the tube 256 is inhaled by the subject 1 without leaking, and the amount of the rare gas inhaled by the subject 1 is largely determined by the regulating means 259. FIG. 4(B) is a diagram showing the operation of the mask section 210 when respiration of the subject 1 is in an expiring state. The internal space of the mask section 210 is at a positive pressure relative to the outer air because of expiration of the subject 1. Thus, the diaphragm 220 deforms to be pushed in a direction opposite to the subject 1. At that time, the movable lever 240 fixed at the side wall 270 moves synchronously with the deformation of the diaphragm 220 until the valve 260 is closed, and thereafter, stops and keeps the closed state. Moreover, the valve 250 is pushed toward the outside against the pressure by the spring 251 because the internal space is at a positive pressure, and discharges the expired air containing carbon dioxide and the like of the subject 1 in the internal space. As described above, in Embodiment 1, gaseous xenon in a hyperpolarized state in the gas bag 600 and the inspired material such as oxygen are supplied to the mask section 210 in a closed state, and a positive or negative pressure in the internal space of the mask section 210 during expiration or inspiration is detected at the diaphragm 220, and discharge from the internal space or intake of xenon and the inspired material such as oxygen to the internal space is conducted based on the detection; and therefore, gaseous xenon in a hyperpolarized state is prevented from leaking to the outer air before being inhaled by the subject 1 and is supplied at a generally constant flow rate and with high quantifiability, and in addition, the inspired material such as oxygen is supplied to the subject 1 without fail, ensuring high safety. EMBODIMENT 2 While the diaphragm 220 deforms synchronously with expiration and inspiration of the subject 1 and respiration is detected by the detection sensor 290 attached on the diaphragm 220 in Embodiment 1, the detected signal can be used to quantitatively analyze acquired image information. Embodiment 2 addresses analysis of a magnetic resonance signal based on such a detected signal of respiration and information of xenon in a hyperpolarized state supplied with quantifiability. Since the hardware configuration of the rare gas polarizer apparatus 3 around the mask section 210 and magnetic resonance imaging apparatus 200 is identical to that shown in FIGS. 1-3, detailed description thereon will be omitted here. FIG. 5(A) is an exemplary respiration signal, detected by the detection sensor 290, that synchronizes with respiration of the subject 1. In a respiration signal region having a high signal value, the subject 1 is in an inspiring state, and in a respiration signal region having a low signal value, the subject 1 is in an expiring state. It should be noted that the expiring state has body motion of the subject 1 slower than the inspiring state, and the expiring state continues longer than the inspiring state. A pulse sequence read from the data management section 770 to the scan controller section 760 is sequentially decoded and executed. At that time, the pulse sequence is executed synchronously with the respiration signal from the detection sensor 290. In the case of the respiration signal exemplarily shown in FIG. 5(A), an inspiration period is detected by thresholding or peak detection, for example, and the execution of the pulse sequence and data collection are conducted after a lag time Td from the inspiration period. By defining a plurality of lag times Td, for example, a temporal change of a process of, starting from the inspiration period in which xenon in a hyperpolarized state is inhaled, absorption of xenon by the subject 1, dissolution of xenon into blood and diffusion throughout the whole body can be observed. FIG. 5(B) represents in a three-dimensional manner spectrum intensity of an RF signal received from the subject 1 as a function of the lag time Td. The three axes represent the lag time Td, difference of spectrum frequency Af, and spectrum intensity, and the plot shows, at each lag time Td, variation of the spectrum with an increasing lag time. In the plot, a gas phase signal indicating xenon in a hyperpolarized state present in the lungs as gas and a dissolution signal indicating xenon in a hyperpolarized state present dissolved into blood have different spectrum frequencies, and are separately observed. As the lag time Td increases, xenon diffuses throughout the whole body and the intensity of the gas phase signal and dissolution signal gradually decreases. At that time, as xenon inhaled into the lungs as gas is absorbed into blood via the alveoli, a peak appears first in the gas phase signal and then in the dissolution phase signal, along the time axis of the lag time Td. Since xenon inhaled into the lungs can be quantitatively estimated, information on the gas phase signal and dissolution signal can be collected and analyzed with quantifiability. As described above, in Embodiment 2, the detection sensor 290 detects the inspiration period, and a pulse sequence is executed after a lag time Td from the inspiration period to collect data, and therefore, data collection synchronous with the phase of respiration of the subject 1 can be conducted, and a process of xenon in a hyperpolarized state being absorbed in the subject 1 over time can be tracked dynamically and with quantifiability. Moreover, while in Embodiment 2, the lag time Td is changed to dynamically track the change of the spectrum intensity, the lag time Td may be fixed to acquire stable tomographic image information with reduced artifacts. As can be seen from FIG. 5(A), the expiring state is longer and has less body motion than the inspiring state. Therefore, in acquiring tomographic image information using xenon in a hyperpolarized state, tomographic image information with reduced motion artifacts can be obtained by setting the lag time Td at the time position in the expiring state. Furthermore, while in Embodiment 2, a pulse sequence is executed with reference to the respiration signal of the subject 1 as shown in FIG. 5(A), it is possible to obtain information on the number of times of respiration from the respiration signal, and optimize the pulse sequence based on the information on the number of times of respiration. In such optimization, the band width, matrix size and the like can be set depending upon the information on the number of times of respiration so that artifacts are reduced or the SNR (signal-to-noise ratio) is improved. Moreover, while in Embodiment 2, a pulse sequence is executed synchronously with the respiration signal of the subject 1 as shown in FIG. 5(A), a respiration signal at the time of execution of the pulse sequence can be appended as additional information to collected data of a magnetic resonance signal. Thus, data selection or image processing can be applied to the collected data based on the respiration signal after the data collection. EMBODIMENT 3 While xenon in a hyperpolarized state and the inspired material such as oxygen are supplied to the closed mask section 210 to achieve supply of xenon with quantifiability in Embodiment 1, the tube 266 for conveying gaseous xenon may be provided with a flowmeter to further improve quantifiability, and optimize parameters such as a gain in data collection using xenon in a hyperpolarized state. FIG. 6 is a diagram showing supplying means 5 in accordance with Embodiment 3. The magnetic resonance imaging apparatus 200, and the gas supply section 50, polarizing section 10, trap section 20, extracting section 30 and rare gas collecting section 60 in the rare gas polarizer apparatus 3 are identical to those shown in FIGS. 1 and 2, and detailed description thereon will be omitted. The supplying means 5 in FIG. 6 comprises the mask section 210, tube 272, tank 262, valve 280, and a flowmeter 44. The mask section 210, tube 272, tank 262 and valve 280 are identical to those of the supplying means 4, and detailed description thereon will be omitted. The flowmeter 44 is attached to the tube 266, and it measures the flow rate of the rare gas flowing in from the gas bag 600. The measured flow rate is transmitted to the scan controller section 760 along with the respiration signal from the mask section 210. The flowmeter 44 may be one that simply obtains the flow rate by using, for example, an orifice plate and determining the pressure difference across the orifice plate. However, the flowmeter 44 is preferably made of a nonmagnetic material. Moreover, the position at which the flowmeter 44 is disposed may be anywhere between the valve 280 and mask section 210. Next, the operation of the supplying means 5 and scan controller section 760 will be described. The supplying means 5 first measures a respiration signal by the mask section 210 attached to the subject 1, and the flow rate of xenon by the flowmeter 44. The scan controller section 760 receives these signals, and calculates the respiration cycle from the respiration signal. Furthermore, the amount of xenon gas inhaled by the subject 1 is thereafter calculated from the respiration cycle and flow rate of xenon. Since the maximum received signal increases approximately in proportion to the amount of xenon in a hyperpolarized state inhaled by the subject 1, the coefficient of proportion is experimentally determined beforehand. From the amount of the gas inhaled by the subject 1 and the experimentally determined coefficient of proportion, an approximate magnitude of the maximum received signal is determined. Based on the magnitude of the maximum received signal, the gain of the amplifier set at a prescan in which no xenon is inhaled can be corrected to an optimum value. As described above, in Embodiment 3, the flowmeter 44 is attached to the tube 266 in the supplying means 5, and the accurate flow rate of xenon is measured along with a respiration signal from the detection sensor 290, and therefore, the amount of xenon gas inhaled by the subject 1 can be accurately predicted, and optimization of the gain of the amplifier, and hence, the SNR, can be achieved by the prediction. Many widely different embodiments of the invention may be constructed without departing from the spirit and the scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described in the specification, except as defined in the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates to a rare gas polarizer apparatus and a magnetic resonance imaging system for producing a rare gas in a hyperpolarized state, and conducting imaging using the rare gas. In recent years, a magnetic resonance image is acquired with high sensitivity with a rare gas isotope such as xenon (Xe), helium (He) etc. in a hyperpolarized state absorbed in a subject by inhalation or injection. To bring the rare gas to a hyperpolarized state, a rare gas polarizer apparatus is employed. The rare gas polarizer apparatus brings a rare gas isotope to a hyperpolarized state in a high temperature cell, and then solidifies only the rare gas in a hyperpolarized state by sublimation of the rare gas in a thermostatic bath containing liquid nitrogen under a high magnetic field environment to extract only the rare gas. The solidified rare gas is then vaporized by warming, and inhaled by the subject (for example, see Patent Document 1). At that time, the vaporized rare gas in a hyperpolarized state is accumulated in a gas bag, vial or the like, and then inhaled by the subject from the outlet of the bag or vial.
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<SOH> SUMMARY OF THE INVENTION <EOH>Therefore, an object of the present invention is to provide a rare gas polarizer apparatus and a magnetic resonance imaging system that supply a rare gas in a hyperpolarized state and an inspired material to a subject with quantifiability and without fail to conduct imaging. To solve the aforementioned problem and attain the object, a rare gas polarizer apparatus in accordance with the invention of a first aspect is characterized in comprising: a polarizing section for bringing a rare gas contained in a mixed gas to a hyperpolarized state; an extracting section for sublimating said rare gas from said mixed gas, extracting said rare gas as a solid, and vaporizing said extracted solid rare gas; and supplying means for mixing said vaporized rare gas with an inspired material, and supplying said gas to a mask section closed against the outer air covering the respiratory organs of the subject. According to the invention of the first aspect, the polarizing section brings a rare gas contained in a mixed gas to a hyperpolarized state, the extracting section sublimates the rare gas from the mixed gas, extracts the rare gas as a solid, and vaporizes the extracted solid rare gas, and the supplying means mixes the vaporized rare gas with an inspired material, and supplies the gas to a mask section closed against the outer air covering the respiratory organs of the subject; and therefore, the rare gas in a hyperpolarized state is prevented from leaking to the outer air, and the rare gas, along with the inspired material including oxygen etc., is inhaled by the subject without fail, so that a rare gas in a hyperpolarized state can be supplied to the subject with quantifiability and safety. A rare gas polarizer apparatus in accordance with the invention of a second aspect is characterized in that: said inspired material is oxygen or air containing oxygen. According to the invention of the second aspect, even though the closed mask section is employed, the subject can continue respiration. A rare gas polarizer apparatus in accordance with the invention of a third aspect is characterized in that: said mask section comprises a diaphragm that is displaced synchronously with respiration of said subject. According to the invention of the third aspect, a pressure change inside the mask section can be detected. A rare gas polarizer apparatus in accordance with the invention of a fourth aspect is characterized in that: said mask section comprises an on-off type intake valve for taking in said vaporized rare gas and said inspired material. According to the invention of the fourth aspect, since the mask section takes in the vaporized rare gas and inspired material through an on-off type intake valve, the intake of the vaporized rare gas and inspired material can be controlled. A rare gas polarizer apparatus in accordance with the invention of a fifth aspect is characterized in that: said intake valve comprises regulating means for regulating the amount of intake of said rare gas and said inspired material. According to the invention of the fifth aspect, since the intake valve regulates the amount of intake of the rare gas and inspired material by the regulating means, finer regulation on the mix ratio between the rare gas and inspired material, for example, can be achieved. A rare gas polarizer apparatus in accordance with the invention of a sixth aspect is characterized in that: said intake valve comprises a stopper at an intake vent for said inspired material for preventing said intake vent from completely closing. According to the invention of the sixth aspect, since the intake valve prevents the intake vent for the inspired material from completely closing by a stopper at the intake vent, the inspired material supplied to the subject is protected against stopping in some abnormal condition. A rare gas polarizer apparatus in accordance with the invention of a seventh aspect is characterized in that: said mask section comprises an on-off type exhaust valve for discharging an expired material from said subject to said outer air. According to the invention of the seventh aspect, since the mask section exhausts an expired material from the subject to the outer air through an on-off type exhaust valve, the expired material such as carbon dioxide can be discharged without fail. A rare gas polarizer apparatus in accordance with the invention of an eighth aspect is characterized in that: said supplying means opens said intake valve in response to displacement of said diaphragm in synchronism with inspiration of said subject, and closes said intake valve in response to displacement of said diaphragm in synchronism with expiration of said subject. According to the invention of the eighth aspect, the rare gas and inspired material can be taken in with inspiration and the intake can be stopped by expiration, synchronously with the displacement of the diaphragm. A rare gas polarizer apparatus in accordance with the invention of a ninth aspect is characterized in that: said supplying means closes said exhaust valve synchronously with inspiration of said subject, and opens said exhaust valve synchronously with expiration of said subject. According to the invention of the ninth aspect, when the intake valve is open the exhaust valve is closed, and when the intake valve is closed the exhaust valve is opened, so that intake of the rare gas and discharge can be achieved efficiently and without waste. A rare gas polarizer apparatus in accordance with the invention of a tenth aspect is characterized in that: said diaphragm comprises a detection sensor for detecting said displacement. According to the invention of the tenth aspect, since the diaphragm detects the displacement by a detection sensor, respiration information can be obtained as an electric signal. A rare gas polarizer apparatus in accordance with the invention of an eleventh aspect is characterized in that: said supplying means comprises a flowmeter for measuring the flow rate of said vaporized rare gas. According to the invention of the eleventh aspect, since the supplying means measures the flow rate of the vaporized rare gas by a flowmeter, more detailed information on the amount of the inhaled rare gas can be obtained. A magnetic resonance imaging system in accordance with the invention of a twelfth aspect comprises: a rare gas polarizer apparatus for supplying a rare gas in a hyperpolarized state to a subject, and a magnetic resonance imaging apparatus for acquiring magnetic resonance information on said subject inhaling said rare gas, and said magnetic resonance imaging system is characterized in that: said rare gas polarizer apparatus has supplying means for supplying said rare gas mixed with an inspired material to a mask section closed against the outer air covering the respiratory organs of said subject; said supplying means has a detection sensor for detecting said respiration; and said magnetic resonance imaging apparatus has a control processing section for conducting said acquisition or optimization of parameters for said acquisition based on respiration information from said detection sensor. According to the invention of the twelfth aspect, in the rare gas polarizer apparatus, the supplying means supplies a rare gas mixed with an inspired material to a mask section closed against the outer air covering the respiratory organs of the subject; in the supplying means, the detection sensor detects the respiration; and in the magnetic resonance imaging apparatus, the control processing section conducts the acquisition or optimization of parameters for the acquisition based on respiration information from the detection sensor; therefore, quantifiability of the rare gas in a hyperpolarized state inhaled by the subject and respiration information including the inhalation allows for quantitative analysis of magnetic resonance information such as tomographic image information on the subject, and moreover, optimization of parameters including the gain or band width in acquiring the magnetic resonance information can be achieved. A magnetic resonance imaging system in accordance with the invention of a thirteenth aspect is characterized in that: said control processing section conducts said acquisition synchronously with the inspiration or expiration indicated in said respiration information. According to the invention of the thirteenth aspect, when tomographic image information on the subject is acquired, artifacts can be reduced; more generally, when magnetic resonance information is acquired, stable information can be obtained. A magnetic resonance imaging system in accordance with the invention of a fourteenth aspect is characterized in that: said control processing section conducts said acquisition after an additional lag time from said synchronization. According to the invention of the fourteenth aspect, by changing the lag time, data can be acquired in any phase of respiration. A magnetic resonance imaging system in accordance with the invention of a fifteenth aspect is characterized in that: said control processing section counts the number of times of respiration from said respiration information and conducts said optimization on parameters based on said number of times of respiration. According to the invention of the fifteenth aspect, information on the speed of motion of the subject based on the number of times of respiration of the subject allows parameters such as the band width and number of data acquisitions to be set for artifact reduction or high SNR. A magnetic resonance imaging system in accordance with the invention of a sixteenth aspect is characterized in that: said parameters include the gain of an amplifier for use in acquiring said magnetic resonance information. According to the invention of the sixteenth aspect, a gain when the rare gas in a hyperpolarized state is inhaled can be optimized from a gain in a prescan. A magnetic resonance imaging system in accordance with the invention of a seventeenth aspect is characterized in that: said supplying means further comprises a flowmeter for measuring the flow rate of said rare gas. According to the invention of the seventeenth aspect, since the supplying means measures the flow rate of the rare gas by a flowmeter, more detailed information on the amount of the inhaled rare gas can be obtained. A magnetic resonance imaging system in accordance with the invention of a seventeenth aspect is characterized in that: said control processing section conducts said optimization of parameters based on flow rate information from said flowmeter. According to the invention of the eighteenth aspect, since detailed information on the amount of the rare gas inhaled by the subject is obtained, adjustment of the gain of the amplifier and other-such tuning can be more finely conducted based on the detailed information. According to the present invention, the polarizing section brings a rare gas contained in a mixed gas to a hyperpolarized state, the extracting section sublimates the rare gas from the mixed gas, extracts the rare gas as a solid, and vaporizes the extracted solid rare gas, and the supplying means mixes the vaporized rare gas with an inspired material, and supplies the gas to a mask section closed against the outer air covering the respiratory organs of the subject; and therefore, the rare gas in a hyperpolarized state is prevented from leaking to the outer air, and the rare gas, along with the inspired material including oxygen etc., is inhaled by the subject without fail, so that a rare gas in a hyperpolarized state can be supplied to the subject with quantifiability and safety. Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.
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20040630
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20051108
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20050106
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60150.0
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ARANA, LOUIS M
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RARE GAS POLARIZER APPARATUS AND MAGNETIC RESONANCE IMAGING SYSTEM
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UNDISCOUNTED
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ACCEPTED
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10,881,476
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ACCEPTED
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Digital predistortion system and method for correcting memory effects within an RF power amplifier
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A system and method of correcting memory effects present within power amplifiers using digital predistortion and an improved power amplifier system employing digital predistortion are disclosed. Nonlinearities within a power amplifier having an input derived from a digital signal are compensated by injecting a digital correction signal prior to the power amplifier. A system and method for modeling the distortion created by power amplifier memory effects and generating the desired digital predistortion correction signal are disclosed.
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1. A digital predistorter adapted to receive a digital input signal and output a predistorted digital signal, the digital predistorter comprising: an input coupled to receive the digital input signal; a first signal path coupled to the input and comprising a delay circuit and a combiner circuit coupled to the output of the delay circuit; a second signal path, coupled to the input in parallel with said first signal path, comprising a first digital predistorter circuit providing a first predistortion operation on the input signal; and a third signal path, coupled to the input in parallel with said first and second signal path, comprising a second digital predistorter circuit providing a second different predistortion operation on the input signal; wherein the combiner circuit receives and combines the outputs of the first and second digital predistorter circuits with the output of the delay circuit of the first signal path to provide a predistorted digital output signal. 2. A digital predistorter as set out in claim 1, wherein said first digital predistorter circuit provides said first predistortion operation modeling memoryless distortion effects employing only a current sample of the digital input signal. 3. A digital predistorter as set out in claim 2, wherein said second digital predistorter circuit provides said second predistortion operation modeling memory distortion effects employing plural samples of the digital input signal. 4. A digital predistorter as set out in claim 1, wherein said combiner circuit comprises a complex addition circuit. 5. A digital predistorter as set out in claim 1, further comprising a second combiner circuit coupled to the outputs of the first and second digital predistorter circuits and providing a combined output of the first and second digital predistorter circuits to the combiner circuit in the first signal path. 6. A digital predistorter as set out in claim 5, wherein said second combiner circuit comprises a complex addition circuit. 7. A digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion correction signal compensating for memory effects due to plural samples of the input signal, the digital predistortion circuit comprising: an input for receiving the digital input signal; a first signal path comprising a delay circuit coupled to the input and a combiner circuit coupled to the output of the delay circuit; a filter bank, coupled to the input and configured in parallel with the first signal path, the filter bank comprising at least two filters having different frequency responses and outputting at least first and second band limited signals derived from plural samples of the digital input signal; and a plurality of nonlinear operation circuits coupled to the filter bank and receiving the band limited signals, the nonlinear operation circuits creating higher order signals from the band limited signals; wherein the outputs of the nonlinear operation circuits are provided to the combiner circuit in the first signal path and combined with the delayed input signal output from the delay circuit in the first signal path to provide a digital predistortion output signal. 8. A digital predistortion circuit as set out in claim 7, further comprising a plurality of weighting circuits coupled to the outputs of the nonlinear operation circuits and applying respective weighting coefficients to the higher order signals. 9. A digital predistortion circuit as set out in claim 8, wherein the input signal has an associated frequency bandwidth, wherein one or more of the higher order signals fall within the bandwidth of the input signal, and wherein the weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. 10. A digital predistortion circuit as set out in claim 7, wherein said combiner circuit is a complex multiplication circuit and wherein the predistortion output signal output from the combiner circuit is a third order signal derived from the input signal and the higher order signals from the nonlinear operation circuits. 11. A digital predistortion circuit as set out in claim 7, further comprising a plurality of complex addition circuits receiving and adding the higher order signals from the plurality of nonlinear operation circuits and providing the combined higher order signals to the combiner circuit in the first signal path. 12. A digital predistortion circuit as set out in claim 7, wherein said filter bank comprises first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response. 13. A digital predistortion circuit as set out in claim 12, wherein said plurality of nonlinear operation circuits comprises: a first nonlinear operation circuit comprising a first complex conjugation circuit receiving the output of the second filter and a first complex multiplication circuit receiving the output of the first complex conjugation circuit and the output of the first filter and providing a first higher order signal; a second nonlinear operation circuit comprising first and second magnitude squared circuits receiving the outputs of the first and second filter, respectively, and an addition circuit adding the outputs of the first and second magnitude squared circuits and providing the output as a second higher order signal; and a third nonlinear operation circuit comprising a second complex conjugation circuit receiving the output of the first filter and a second complex multiplication circuit multiplying the output of the second complex conjugation circuit and the output of the second filter to provide a third higher order signal. 14. A digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal, the digital predistortion circuit comprising: an input for receiving the digital input signal; a first signal path comprising a delay circuit coupled to the input and a combiner circuit coupled to the output of the delay circuit; a nonlinear operation circuit coupled to the input and configured in parallel with the first signal path and receiving the digital input signal, the nonlinear operation circuit creating a higher order signal from the digital input signal; and a filter bank, coupled to the nonlinear operation circuit and receiving the higher order signal, the filter bank comprising plural filters having different frequency responses and outputting plural band limited higher order signals derived from plural samples of the higher order signal; wherein the outputs of the filters are provided to the combiner circuit in the first signal path and combined with the delayed input signal output from the delay circuit in the first signal path to provide a digital predistortion output signal. 15. A digital predistortion circuit as set out in claim 14, wherein said input signal is a complex signal and wherein said nonlinear operation circuit comprises a magnitude squared circuit providing a signal corresponding to the magnitude squared of the complex digital input signal. 16. A digital predistortion circuit as set out in claim 14, further comprising a plurality of weighting circuits coupled to the outputs of the plurality of filters and applying respective weighting coefficients to the band limited higher order signals. 17. A digital predistortion circuit as set out in claim 16, wherein the input signal has an associated frequency bandwidth, wherein one or more of the band limited higher order signals fall within the bandwidth of the input signal, and wherein the weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. 18. A digital predistortion circuit as set out in claim 14, wherein said combiner circuit is a complex multiplication circuit and wherein the predistortion output signal output from the combiner circuit is a third order signal derived from the input signal and the band limited higher order signals. 19. A digital predistortion circuit as set out in claim 14, further comprising a plurality of complex addition circuits receiving and adding the band limited higher order signals and providing the combined band limited higher order signals to the combiner circuit in the first signal path. 20. A digital predistortion circuit as set out in claim 14, wherein said filter bank comprises first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response, and a third filter having a different frequency response than said first and second filters. 21. A digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal, the digital predistortion circuit comprising: an input for receiving the digital input signal; a filter bank comprising at least two filters having different frequency responses and outputting at least first and second band limited signals derived from plural samples of the digital input signal; a plurality of nonlinear operation circuits coupled to the filter bank and receiving the band limited signals, the nonlinear operation circuits creating third order or higher order signals from the band limited signals; and one or more combiner circuits receiving and combining the outputs of the nonlinear operation circuits to provide a digital predistortion output signal. 22. A digital predistortion circuit as set out in claim 21, further comprising a plurality of weighting circuits coupled to the outputs of the nonlinear operation circuits and applying respective weighting coefficients to the higher order signals. 23. A digital predistortion circuit as set out in claim 22, wherein the input signal has an associated frequency bandwidth, wherein one or more of the higher order signals fall within the bandwidth of the input signal, and wherein the weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. 24. A digital predistortion circuit as set out in claim 21, wherein said one or more combiner circuits comprise a plurality of complex addition circuits. 25. A digital predistortion circuit as set out in claim 21, wherein said filter bank comprises first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response. 26. A digital predistortion circuit as set out in claim 25, wherein said plurality of nonlinear operation circuits comprises: a first nonlinear operation circuit comprising a first complex squaring circuit receiving the output of the first filter, a first conjugation circuit receiving the output of the second filter, and a first complex multiplication circuit receiving the output of the complex squaring circuit and the first complex conjugation circuit and providing a first higher order signal; a second nonlinear operation circuit comprising first and second magnitude squared circuits receiving the outputs of the first and second filter, respectively, an addition circuit adding the outputs of the first and second magnitude squared circuits, and a second complex multiplication circuit multiplying the output of the first filter and the output of the addition circuit and providing the output as a second higher order signal; a third nonlinear operation circuit comprising a third complex multiplication circuit receiving and multiplying the output of the second filter and the output of said addition circuit and providing the output as a third higher order signal; and a fourth nonlinear operation circuit comprising a second complex conjugation circuit receiving the output of the first filter, a second complex squaring circuit receiving the output of the second filter, and a fourth complex multiplication circuit multiplying the output of the second complex conjugation circuit and the output of the second complex squaring circuit to provide a fourth higher order signal. 27. A digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal, the digital predistortion circuit comprising: an input for receiving the digital input signal; a nonlinear operation circuit coupled to the input and receiving the digital input signal, the nonlinear operation circuit creating third or higher order signals from the digital input signal; a filter bank, coupled to the nonlinear operation circuit and receiving the third or higher order signals, the filter bank comprising plural filters having different frequency responses and outputting plural band limited third order or higher order signals derived from plural samples of the third or higher order signal; and one or more combiner circuits receiving and combining the outputs of the filters to provide a predistortion output signal. 28. A digital predistortion circuit as set out in claim 27, wherein said input signal is a complex signal and wherein said nonlinear operation circuit comprises a circuit providing a third order signal corresponding to the magnitude squared of the complex digital input signal multiplied by the complex digital input signal. 29. A digital predistortion circuit as set out in claim 27, further comprising a plurality of weighting circuits coupled to the outputs of the plurality of filters and applying respective weighting coefficients to the band limited third order or higher order signals. 30. A digital predistortion circuit as set out in claim 29, wherein the input signal has an associated frequency bandwidth, wherein one or more of the band limited third order or higher order signals fall at least partially within the bandwidth of the input signal, and wherein the weighting coefficients apply a selective weighting for the one or more third order or higher order signals within the bandwidth of the input signal. 31. A digital predistortion circuit as set out in claim 27, wherein said one or more combiner circuits comprise a plurality of complex addition circuits receiving and adding the band limited third order or higher order signals. 32. A digital predistortion circuit as set out in claim 27, wherein said filter bank comprises first, second, third and fourth filters each having a different fixed frequency response. 33. An adaptive digital predistortion system adapted to receive a digital input signal and output a predistorted digital signal to a nonlinear component and to receive a digital sample of the output of the nonlinear component, the digital predistortion system comprising: an input coupled to receive the digital input signal; a digital predistorter module coupled to the input and comprising a predistortion circuit operating on the digital input signal to create band limited signals from the input signal and employing separate predistortion coefficients for weighting the band limited signals; an error generator circuit for receiving the digital input signal and the digital sample of the output of the nonlinear component and providing a digital error signal; and an adaptive coefficient generator coupled to receive the digital input signal and the digital error signal and comprising a spectral weighting circuit to derive separately weighted frequency components from the input signal and error signal and a coefficient estimator circuit for calculating updated predistortion coefficients weighted differently for different frequency components and providing the updated predistortion coefficients to the digital predistorter module. 34. An adaptive digital predistortion system as set out in claim 33, wherein the coefficient estimator circuit comprises a weighted least mean square coefficient estimator. 35. An adaptive digital predistortion system as set out in claim 34, wherein the coefficient estimator circuit comprises a digital signal processor programmed with a weighted least mean square algorithm. 37. An adaptive digital predistortion system as set out in claim 33, wherein the spectral weighting circuit comprises a plurality of digital filters receiving and operating on the digital input signal and the digital error signal. 38. An adaptive digital predistortion system as set out in claim 33, wherein the spectral weighting circuit further comprises a subsequence calculation circuit for deriving frequency limited subsequences from the digital input signal and wherein one of the plurality of digital filters receive and operate on the digital error signal and the remaining ones of the plurality of digital filters receive and operate on the frequency limited subsequences. 39. A linearized amplifier system adapted to receive a digital input signal and output an amplified RF signal, comprising: an input coupled to receive the digital input signal; a digital predistorter module comprising a first signal path coupled to the input and comprising a delay circuit and a combiner circuit coupled to the output of the delay circuit, a second signal path coupled to the input in parallel with said first signal path and comprising a first digital predistorter circuit providing a memoryless predistortion operation on the input signal operating on single samples of the input signal, and a third signal path coupled to the input in parallel with said first and second signal paths and comprising a second digital predistorter circuit providing a memory based predistortion operation on the input signal employing plural samples of the input signal, wherein the combiner circuit receives and combines the outputs of the first and second digital predistorter circuits with the output of the delay circuit of the first signal path to provide a predistorted digital signal; a digital to analog converter coupled to receive the predistorted digital signal from the digital predistorter module and provide a predistorted analog signal; an up converter receiving the predistorted analog signal from the digital to analog converter and converting it to an RF analog signal; and a power amplifier receiving the RF analog signal and providing an amplified RF output signal. 40. An adaptively linearized amplifier system, comprising: an input coupled to receive a digital input signal; a digital predistorter module coupled to the input and receiving the digital input signal and outputting a predistorted digital signal, the digital predistorter module comprising a predistortion circuit operating on the digital input signal to create band limited signals from the input signal and employing separate predistortion coefficients for weighting the band limited signals; a digital to analog converter coupled to receive the predistorted digital signal output of the digital predistorter module and provide an analog signal; an up converter for receiving the analog signal from the digital to analog converter and converting it to an RF analog signal; a power amplifier receiving the RF analog signal and providing an amplified RF output signal; an output sampling coupler coupled to sample the analog RF output signal from the power amplifier; a feedback circuit path, coupled to the output sampling coupler, comprising a down converter and an analog to digital converter converting the sampled RF output signal to a digital sampled signal representative of the RF output signal; an error generator circuit coupled to the input and the feedback circuit path for receiving the digital input signal and the digital sampled signal and providing a digital error signal; and an adaptive coefficient generator, coupled to receive the digital input signal and the digital error signal and providing updated predistortion coefficients to the digital predistorter module, comprising a spectral weighting circuit to derive separately weighted frequency components from the digital input signal and digital error signal and a coefficient estimator circuit for calculating updated predistortion coefficients weighted differently for different frequency components. 41. A method for digitally predistorting a digital input signal, comprising: receiving a digital input signal and splitting the digital input signal along three parallel signal paths; delaying the signal provided along the first signal path; digitally predistorting the signal provided along the second signal path employing a single sample of the input signal to provide a memoryless predistortion correction; digitally predistorting the signal along the third signal path employing plural samples of the input signal to provide a memory based digital predistortion correction; and combining the memoryless and memory based digital predistortion corrections provided from the second and third signal paths with the delayed signal in the first signal path to provide a predistorted digital output signal. 42. A method for digitally predistorting a digital input signal, comprising: receiving a digital input signal; deriving a plurality of band limited higher order signals from the digital input signal; weighting the plurality of band limited higher order signals with predistortion coefficients varying between the band limited higher order signals to provide a predistortion correction signal; and combining the predistortion correction signal with the digital input signal to provide a predistorted digital output signal. 43. A method for digitally predistorting a digital input signal as set out in claim 42, wherein deriving a plurality of band limited higher order signals from the digital input signal comprises filtering the input signal to create plural band limited signals and performing plural nonlinear operations on the band limited signals to create said band limited higher order signals. 44. A method for digitally predistorting a digital input signal as set out in claim 42, wherein deriving a plurality of band limited higher order signals from the digital input signal comprises performing a nonlinear operation on the input signal to create a higher order signal and performing plural filtering operations on the higher order signal to create said band limited higher order signals. 45. A method for digitally predistorting a digital input signal as set out in claim 42, wherein said band limited higher order signals are second order signals and wherein said method further comprises multiplying the band limited higher-order signals with the digital input signal to provide a third order digital signal as said predistortion correction signal. 46. A method for digitally predistorting a digital input signal as set out in claim 42, wherein said band limited higher order signals are third order signals. 47. A method for digitally predistorting a digital input signal as set out in claim 42, wherein the input signal has an associated frequency bandwidth, wherein one or more of the band limited higher order signals fall within the frequency bandwidth of the input signal, and wherein the predistortion coefficients apply a selective weighting for the one or more higher order signals within the frequency bandwidth of the input signal. 48. A method for digitally predistorting a digital input signal, comprising: receiving a digital input signal; deriving a plurality of higher order signals representative of nonlinear basis functions based on a joint time frequency representation of plural samples of the digital input signal; weighting the plurality of higher order signals with predistortion coefficients to provide a predistortion correction signal; and combining the predistortion correction signal with the digital input signal to provide a predistorted digital signal. 49. A method for digitally predistorting a digital input signal as set out in claim 48, wherein said nonlinear basis functions comprise truncated Gaussian functions based on a Gabor expansion of the input signal. 50. A method for adaptive digital predistortion linearization of an amplifier system, comprising: receiving a digital input signal; deriving a plurality of band limited higher order signals from the digital input signal; weighting the plurality of band limited higher order signals with spectrally weighted predistortion coefficients to provide a predistortion correction signal; combining the predistortion correction signal with the digital input signal to provide a predistorted digital signal; converting the predistorted digital signal from digital to analog form to provide a predistorted analog signal; up converting the predistorted analog signal to an RF signal; amplifying the RF signal to provide an amplified RF output signal; sampling the RF output signal; down converting the sampled RF output signal to a lower frequency sampled analog output signal; converting the lower frequency sampled analog output signal to digital form to provide a sampled digital output signal; deriving an error signal from the input digital signal and the sampled digital output signal; deriving spectrally weighted subsignals from the error signal and the digital input signal; and adaptively generating said spectrally weighted predistortion coefficients from the spectrally weighted subsignals.
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RELATED APPLICATION INFORMATION The present application claims priority under 35 USC 119 (e) to provisional application Ser. No. 60/485,246 filed Jul. 3, 2003, the disclosure of which is incorporated herein by reference its entirety. FIELD OF THE INVENTION The present invention relates to linearization of RF power amplifiers. More particularly, the present invention relates to digital predistortion linearization of RF power amplifiers. BACKGROUND OF THE INVENTION In the RF transmission of digital information, sampled data sequences are converted to analog signals and processed, subsequently, by various operations containing unwanted nonlinearities. The primary source of nonlinearity is the power amplifier (PA). Nonlinear behavior of the PA (or other devices) can be compensated using digital predistortion. That is, the correction signal is a sampled sequence applied prior to the PA. The correction signal, denoted by XDPD(nT), is represented as a set of higher-order sub-signals corresponding to nonlinear modes in the transmitter. The nonlinear behaviour of the PA transfer characteristics can be classified as memoryless or memory-based. For a memoryless nonlinear device, the nonlinear modes are functions of the instantaneous input value, x(t), only. In contrast, for a PA exhibiting memory effects, the nonlinear modes are functions of both instantaneous and past input values. In general, memory effects exist in any PA; however, the effect becomes more apparent when the bandwidth of the input signal is large. As a result, the correction of memory effects is becoming increasingly more important as wide bandwidth modulation formats are put in use. Accordingly a need presently exists for a system and method for correcting distortion in power amplifiers and especially distortion due to memory effects. SUMMARY OF THE INVENTION In a first aspect the present invention provides a digital predistorter adapted to receive a digital input signal and output a predistorted digital signal. The digital predistorter comprises an input coupled to receive the digital input signal. A first signal path is coupled to the input and comprises a delay circuit and a combiner circuit coupled to the output of the delay circuit. A second signal path is coupled to the input in parallel with the first signal path and comprises a first digital predistorter circuit providing a first predistortion operation on the input signal. A third signal path is coupled to the input in parallel with the first and second signal path and comprises a second digital predistorter circuit providing a second different predistortion operation on the input signal. The combiner circuit receives and combines the outputs of the first and second digital predistorter circuits with the output of the delay circuit of the first signal path to provide a predistorted digital output signal. In a preferred embodiment the first digital predistorter circuit provides the first predistortion operation modeling memoryless distortion effects employing only a current sample of the digital input signal. The second digital predistorter circuit provides the second predistortion operation modeling memory distortion effects employing plural samples of the digital input signal. The combiner circuit preferably comprises a complex addition circuit. The digital predistorter may further comprise a second combiner circuit, coupled to the outputs of the first and second digital predistorter circuits, and providing a combined output of the first and second digital predistorter circuits to the combiner circuit in the first signal path. The second combiner circuit preferably comprises a complex addition circuit. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion correction signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a first signal path comprising a delay circuit coupled to the input and a combiner circuit coupled to the output of the delay circuit. The digital predistortion circuit further comprises a filter bank, coupled to the input and configured in parallel with the first signal path, comprising at least two filters having different frequency responses and outputting at least first and second band limited signals derived from plural samples of the digital input signal. A plurality of nonlinear operation circuits are coupled to the filter bank and receive the band limited signals, the nonlinear operation circuits creating higher order signals from the band limited signals. The outputs of the nonlinear operation circuits are provided to the combiner circuit in the first signal path and combined with the delayed input signal output from the delay circuit in the first signal path to provide a digital predistortion output signal. In a preferred embodiment the digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the nonlinear operation circuits and applying respective weighting coefficients to the higher order signals. The input signal will have an associated frequency bandwidth and one or more of the higher order signals will fall within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. The combiner circuit preferably is a complex multiplication circuit and the predistortion output signal output from the combiner circuit is a third order signal derived from the input signal and the higher order signals from the nonlinear operation circuits. The digital predistortion circuit may further comprise a plurality of complex addition circuits receiving and adding the higher order signals from the plurality of nonlinear operation circuits and providing the combined higher order signals to the combiner circuit in the first signal path. The filter bank may comprise first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response. The plurality of nonlinear operation circuits may comprise first, second and third nonlinear operation circuits. The first nonlinear operation circuit comprises a first complex conjugation circuit receiving the output of the second filter and a first complex multiplication circuit receiving the output of the first complex conjugation circuit and the output of the first filter and providing a first higher order signal. The second nonlinear operation circuit comprises first and second magnitude squared circuits receiving the outputs of the first and second filter, respectively, and an addition circuit adding the outputs of the first and second magnitude squared circuits and providing the output as a second higher order signal. The third nonlinear operation circuit comprises a second complex conjugation circuit receiving the output of the first filter and a second complex multiplication circuit multiplying the output of the second complex conjugation circuit and the output of the second filter to provide a third higher order signal. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a first signal path comprising a delay circuit coupled to the input and a combiner circuit coupled to the output of the delay circuit. The digital predistortion circuit further comprises a nonlinear operation circuit coupled to the input and configured in parallel with the first signal path and receiving the digital input signal, the nonlinear operation circuit creating a higher order signal from the digital input signal. A filter bank is coupled to the nonlinear operation circuit and receives the higher order signal, the filter bank comprising plural filters having different frequency responses and outputting plural band limited higher order signals derived from plural samples of the higher order signal. The outputs of the filters are provided to the combiner circuit in the first signal path and combined with the delayed input signal output from the delay circuit in the first signal path to provide a digital predistortion output signal. In a preferred embodiment of the digital predistortion circuit the input signal is a complex signal and the nonlinear operation circuit comprises a magnitude squared circuit providing a signal corresponding to the magnitude squared of the complex digital input signal. The digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the plurality of filters and applying respective weighting coefficients to the band limited higher order signals. The input signal will have an associated frequency bandwidth, and one or more of the band limited higher order signals fall within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. The combiner circuit is preferably a complex multiplication circuit and the predistortion output signal output from the combiner circuit is a third order signal derived from the input signal and the band limited higher order signals. The digital predistortion circuit may also further comprise a plurality of complex addition circuits receiving and adding the band limited higher order signals and providing the combined band limited higher order signals to the combiner circuit in the first signal path. The filter bank may comprise first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response, and a third filter having a different frequency response than said first and second filters. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a filter bank comprising at least two filters having different frequency responses and outputting at least first and second band limited signals derived from plural samples of the digital input signal. The digital predistortion circuit further comprises a plurality of nonlinear operation circuits coupled to the filter bank and receiving the band limited signals, the nonlinear operation circuits creating third order or higher order signals from the band limited signals, and one or more combiner circuits receiving and combining the outputs of the nonlinear operation circuits to provide a digital predistortion output signal. In a preferred embodiment the digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the nonlinear operation circuits and applying respective weighting coefficients to the higher order signals. The input signal will have an associated frequency bandwidth and one or more of the higher order signals fall within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. The one or more combiner circuits preferably comprise a plurality of complex addition circuits. The filter bank may comprise first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response. The plurality of nonlinear operation circuits may comprise first, second, third and fourth nonlinear operation circuits. The first nonlinear operation circuit comprises a first complex squaring circuit receiving the output of the first filter, a first conjugation circuit receiving the output of the second filter, and a first complex multiplication circuit receiving the output of the complex squaring circuit and the first complex conjugation circuit and providing a first higher order signal. The second nonlinear operation circuit comprises first and second magnitude squared circuits receiving the outputs of the first and second filter, respectively, an addition circuit adding the outputs of the first and second magnitude squared circuits, and a second complex multiplication circuit multiplying the output of the first filter and the output of the addition circuit and providing the output as a second higher order signal. The third nonlinear operation circuit comprises a third complex multiplication circuit receiving and multiplying the output of the second filter and the output of the addition circuit and providing the output as a third higher order signal. The fourth nonlinear operation circuit comprises a second complex conjugation circuit receiving the output of the first filter, a second complex squaring circuit receiving the output of the second filter, and a fourth complex multiplication circuit multiplying the output of the second complex conjugation circuit and the output of the second complex squaring circuit to provide a fourth higher order signal. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a nonlinear operation circuit coupled to the input and receiving the digital input signal. The digital predistortion circuit further comprises a nonlinear operation circuit creating third or higher order signals from the digital input signal. A filter bank is coupled to the nonlinear operation circuit and receives the third or higher order signals, the filter bank comprising plural filters having different frequency responses and outputting plural band limited third order or higher order signals derived from plural samples of the third or higher order signal. The digital predistortion circuit further comprises one or more combiner circuits receiving and combining the outputs of the filters to provide a predistortion output signal. In a preferred embodiment of the digital predistortion circuit the input signal is a complex signal and the nonlinear operation circuit comprises a circuit providing a third order signal corresponding to the magnitude squared of the complex digital input signal multiplied by the complex digital input signal. The digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the plurality of filters and applying respective weighting coefficients to the band limited third order or higher order signals. The input signal will have an associated frequency bandwidth, and one or more of the band limited third order or higher order signals fall at least partially within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more third order or higher order signals within the bandwidth of the input signal. The one or more combiner circuits preferably comprise a plurality of complex addition circuits receiving and adding the band limited third order or higher order signals. The filter bank may comprise first, second, third and fourth filters each having a different fixed frequency response. According to another aspect the present invention provides an adaptive digital predistortion system adapted to receive a digital input signal and output a predistorted digital signal to a nonlinear component and to receive a digital sample of the output of the nonlinear component. The digital predistortion system comprises an input coupled to receive the digital input signal. A digital predistorter module is coupled to the input and comprises a predistortion circuit operating on the digital input signal to create band limited signals from the input signal and employing separate predistortion coefficients for weighting the band limited signals. The digital predistortion system further comprises an error generator circuit for receiving the digital input signal and the digital sample of the output of the nonlinear component and providing a digital error signal. The digital predistortion system further comprises an adaptive coefficient generator, coupled to receive the digital input signal, and the digital error signal and comprising a spectral weighting circuit to derive separately weighted frequency components from the input signal and error signal and a coefficient estimator circuit for calculating updated predistortion coefficients weighted differently for different frequency components and providing the updated predistortion coefficients to the digital predistorter module. In a preferred embodiment of the adaptive digital predistortion system the coefficient estimator circuit comprises a weighted least mean square coefficient estimator. The coefficient estimator circuit preferably comprises a digital signal processor programmed with a weighted least mean square algorithm. The spectral weighting circuit preferably comprises a plurality of digital filters receiving and operating on the digital input signal and the digital error signal. The spectral weighting circuit preferably further comprises a subsequence calculation circuit for deriving frequency limited subsequences from the digital input signal and one of the plurality of digital filters receives and operates on the digital error signal and the remaining ones of the plurality of digital filters receive and operate on the frequency limited subsequences. According to another aspect the present invention provides a linearized amplifier system adapted to receive a digital input signal and output an amplified RF signal. The linearized amplifier system comprises an input coupled to receive the digital input signal. The linearized amplifier system further comprises a digital predistorter module. The digital predistorter module comprises a first signal path coupled to the input, the first signal path comprising a delay circuit and a combiner circuit coupled to the output of the delay circuit. The digital predistorter module further comprises a second signal path, coupled to the input in parallel with the first signal path, comprising a first digital predistorter circuit providing a memoryless predistortion operation on the input signal operating on single samples of the input signal. The digital predistorter module further comprises a third signal path, coupled to the input in parallel with the first and second signal paths, comprising a second digital predistorter circuit providing a memory based predistortion operation on the input signal employing plural samples of the input signal. The combiner circuit of the digital predistorter module receives and combines the outputs of the first and second digital predistorter circuits with the output of the delay circuit of the first signal path to provide a predistorted digital signal. The linearized amplifier system further comprises a digital to analog converter coupled to receive the predistorted digital signal from the digital predistorter module and provide a predistorted analog signal and an up converter receiving the predistorted analog signal from the digital to analog converter and converting it to an RF analog signal. The linearized amplifier system further comprises a power amplifier receiving the RF analog signal and providing an amplified RF output signal. According to another aspect the present invention provides an adaptively linearized amplifier system. The adaptively linearized amplifier system comprises an input coupled to receive a digital input signal. The adaptively linearized amplifier system further comprises a digital predistorter module coupled to the input and receiving the digital input signal and outputting a predistorted digital signal. The digital predistorter module comprises a predistortion circuit operating on the digital input signal to create band limited signals from the input signal and employing separate predistortion coefficients for weighting the band limited signals. The adaptively linearized amplifier system further comprises a digital to analog converter coupled to receive the predistorted digital signal output of the digital predistorter module and provide an analog signal and an up converter for receiving the analog signal from the digital to analog converter and converting it to an RF analog signal. The adaptively linearized amplifier system further comprises a power amplifier receiving the RF analog signal and providing an amplified RF output signal. An output sampling coupler is coupled to sample the analog RF output signal from the power amplifier. The adaptively linearized amplifier system further comprises a feedback circuit path, coupled to the output sampling coupler, comprising a down converter and an analog to digital converter converting the sampled RF output signal to a digital sampled signal representative of the RF output signal. The adaptively linearized amplifier system further comprises an error generator circuit coupled to the input and the feedback circuit path for receiving the digital input signal and the digital sampled signal and providing a digital error signal. The adaptively linearized amplifier system further comprises an adaptive coefficient generator, coupled to receive the digital input signal and the digital error signal, and providing updated predistortion coefficients to the digital predistorter module. The adaptive coefficient generator comprises a spectral weighting circuit to derive separately weighted frequency components from the digital input signal and digital error signal and a coefficient estimator circuit for calculating updated predistortion coefficients weighted differently for different frequency components. According to another aspect the present invention provides a method for digitally predistorting a digital input signal. The method comprises receiving a digital input signal and splitting the digital input signal along three parallel signal paths. The method further comprises delaying the signal provided along the first signal path. The method further comprises digitally predistorting the signal provided along the second signal path employing a single sample of the input signal to provide a memoryless predistortion correction. The method further comprises digitally predistorting the signal along the third signal path employing plural samples of the input signal to provide a memory based digital predistortion correction. The method further comprises combining the memoryless and memory based digital predistortion corrections provided from the second and third signal paths with the delayed signal in the first signal path to provide a predistorted digital output signal. According to another aspect the present invention provides a method for digitally predistorting a digital input signal. The method comprises receiving a digital input signal and deriving a plurality of band limited higher order signals from the digital input signal. The method further comprises weighting the plurality of band limited higher order signals with predistortion coefficients varying between the band limited higher order signals to provide a predistortion correction signal. The method further comprises combining the predistortion correction signal with the digital input signal to provide a predistorted digital output signal. In a preferred embodiment of the method for digitally predistorting a digital input signal deriving a plurality of band limited higher order signals from the digital input signal comprises filtering the input signal to create plural band limited signals and performing plural nonlinear operations on the band limited signals to create the band limited higher order signals. Alternatively, deriving a plurality of band limited higher order signals from the digital input signal preferably comprises performing a nonlinear operation on the input signal to create a higher order signal and performing plural filtering operations on the higher order signal to create said band limited higher order signals. The band limited higher order signals may be second order signals and the method may further comprise multiplying the band limited higher-order signals with the digital input signal to provide a third order digital signal as the predistortion correction signal. Alternatively the band limited higher order signals may be third order signals. The input signal has an associated frequency bandwidth, and one or more of the band limited higher order signals fall within the frequency bandwidth of the input signal. The predistortion coefficients preferably apply a selective weighting for the one or more higher order signals within the frequency bandwidth of the input signal. According to another aspect the present invention provides a method for digitally predistorting a digital input signal. The method comprises receiving a digital input signal and deriving a plurality of higher order signals representative of nonlinear basis functions based on a joint time frequency representation of plural samples of the digital input signal. The method further comprises weighting the plurality of higher order signals with predistortion coefficients to provide a predistortion correction signal. The method further comprises combining the predistortion correction signal with the digital input signal to provide a predistorted digital signal. In a preferred embodiment of the method for digitally predistorting a digital input signal the nonlinear basis functions comprise truncated Gaussian functions based on a Gabor expansion of the input signal. According to another aspect the present invention provides a method for adaptive digital predistortion linearization of an amplifier system. The method comprises receiving a digital input signal and deriving a plurality of band limited higher order signals from the digital input signal. The method further comprises weighting the plurality of band limited higher order signals with spectrally weighted predistortion coefficients to provide a predistortion correction signal, and combining the predistortion correction signal with the digital input signal to provide a predistorted digital signal. The method further comprises converting the predistorted digital signal from digital to analog form to provide a predistorted analog signal and up converting the predistorted analog signal to an RF signal. The method further comprises amplifying the RF signal to provide an amplified RF output signal. The method further comprises sampling the RF output signal and down converting the sampled RF output signal to a lower frequency sampled analog output signal. The method further comprises converting the lower frequency sampled analog output signal to digital form to provide a sampled digital output signal. An error signal is derived from the input digital signal and the sampled digital output signal. The method further comprises deriving spectrally weighted subsignals from the error signal and the digital input signal and adaptively generating said spectrally weighted predistortion coefficients from the spectrally weighted subsignals. Further features and advantages are described in the following detailed description of the invention. BRIEF SUMMARY OF THE DRAWINGS FIG. 1 is a block schematic drawing of a linearized power amplifier system employing digital predistortion linearization in accordance with a preferred embodiment of the present invention. FIGS. 2A, 2B and 2C are graphical representations of time-shifted and frequency-modulated Gaussian functions in the time domain, frequency domain and joint time and frequency domain, respectively. FIGS. 3A and 3B are graphical representations of sampling locations for a time series representation and a joint time-frequency representation of a digital signal, respectively. FIG. 4 is a graphical representations of a basis function and the effect of a time delay on the basis function. FIG. 5 is a block schematic drawing of a first embodiment of the memory digital predistortion circuit employed in the power amplifier system of FIG. 1. FIG. 6 is a block schematic drawing of an alternate implementation of the first embodiment of the memory digital predistortion circuit employed in the power amplifier system of FIG. 1. FIG. 7 is a block schematic drawing of a digital predistortion linearized power amplifier system employing adaptive generation of predistortion coefficients in accordance with a preferred embodiment of the present invention. FIG. 8 is a block schematic drawing of an adaptive coefficient generator employed in the power amplifier system of FIG. 7 in accordance with a preferred embodiment of the present invention. FIG. 9 is a block schematic drawing of a preferred embodiment of the third-order mode subsequence calculation circuit employed in FIG. 8 in an implementation using the embodiment of the memory digital predistortion circuit shown in FIG. 5. FIG. 10 is a block schematic drawing of a preferred embodiment of the third-order mode subsequence calculation circuit employed in FIG. 8 in an implementation using the embodiment of the memory digital predistortion circuit shown in FIG. 6. FIG. 11 is a block schematic drawing of a second embodiment of the memory digital predistortion circuit employed in the power amplifier system FIG. 1 and FIG. 7. FIG. 12 is a block schematic drawing of an alternate implementation of the second embodiment of the memory digital predistortion circuit employed in the power amplifier system of FIG. 1 and FIG. 7. FIG. 13 is a block schematic drawing of an adaptive coefficient generator employed in the power amplifier system of FIG. 7 in accordance with an implementation using the embodiment of the memory digital predistortion circuit shown in FIG. 11 or 12. FIG. 14 is a block schematic drawing of a preferred embodiment of the third-order mode subsequence calculation circuit employed in FIG. 13 in an implementation using the embodiment of the memory digital predistortion circuit shown in FIG. 11. FIG. 15 is a block schematic drawing of a preferred embodiment of the third-order mode subsequence calculation circuit employed in FIG. 13 in an implementation using the embodiment of the memory digital predistortion circuit shown in FIG. 12. DETAILED DESCRIPTION A preferred embodiment of a linearized power amplifier system employing digital predistortion linearization in accordance with the present invention is generally shown in FIG. 1. As indicated, the power amplifier system may preferably be part of a communication system including a transmitter, such as a cellular wireless communication system. As shown in FIG. 1 a digital input signal is applied at the input 102 and provided to digital predistorter 100. The digital input signal may typically be provided in complex form having an in phase (I) and quadrature (Q) component, as is well known in the art, and such is implied herein although single signal lines are shown for ease of illustration. For example, the input signal may be any of a number of known wide bandwidth signals, such as CDMA and WCDMA signals, employed in cellular wireless communications systems. The digital predistorter 100 implements a predistortion operation on the input signal to compensate for nonlinearities introduced by the power amplifier 110 in transmitter 104. In addition to the power amplifier 110 the transmitter 104 may include conventional digital to analog converter (DAC) stage 106 and up converter stage 108 and optionally additional conventional components employed in wireless communications applications. The predistortion operation implemented by digital predistorter 100 may also optionally correct any nonlinearities provided by such other components of the transmitter 104. The amplified analog signal is provided at output 112, typically to a conventional antenna system in a cellular wireless communications application (not shown). As shown in FIG. 1, the digital predistorter 100 includes three parallel signal paths 114, 116 and 118. The first signal path 114 provides a simple delay to the input digital signal, i.e., without any predistortion applied to the signal. This delay is provided to equal the delays inherent in the second and third signal paths 116 and 118 so that the signals from the three paths can be synchronized when combined at combining circuitry 120. The second two paths, 116 and 118 correspond to memoryless digital predistortion (DPD) and memory digital predistortion (DPD) circuit blocks, respectively. The memoryless and memory digital predistortion operations are implemented in separate signal paths to allow each predistortion operation to be maximized for both efficiency and effectiveness in compensating for the different sources of nonlinearity. As will be discussed below in detail, the memory DPD circuit block is preferably based on a polynomial model of the nonlinearity. However, the memoryless DPD circuit block may be implemented differently, for example, using a look-up table (LUT) that maps PA gain corrections to the input power (or magnitude). Also, the memoryless DPD circuit block 116 will operate on single samples of the input signal to generate individual digital predistortion corrections while the memory DPD block 118 operates on plural samples of the input signal as described in detail below. Separating the memoryless and memory DPD operations thus allows the use of different structures or different orders of correction. The memory DPD circuit block has the potential to correct part of the memoryless distortion, which would reduce the burden on the memoryless DPD (and vice versa). However, due to this interaction, the adaptation of the two DPD circuit blocks should preferably not be concurrent (an adaptive embodiment of the present invention is described in detail below in relation to FIG. 7). The two predistortion corrections provided by memoryless DPD circuit block 116 and memory DPD circuit block 118 are combined at combining circuit 122, which may be a complex addition circuit, to form a combined predistortion correction to the input signal. This combined predistortion correction signal is then applied to the input signal at main path combining circuit 120, which may also be a complex addition circuit, to provide a predistorted digital signal. This predistorted digital signal is provided along line 124 to the digital input of transmitter circuitry 104. The subsequent operation of transmitter circuitry 104, and especially the nonlinear operation of amplifier 110, on the digital predistorted input signal introduces offsetting memory based and memoryless distortion resulting in a substantially linear analog output signal at system output 112. The memoryless DPD circuit block 116 may be implemented using various techniques including a LUT based circuit block, as noted above. For example, a LUT based DPD implementation suitable for circuit block 116 is disclosed in U.S. patent application Ser. No. 10/818,547 filed Apr. 5, 2004, the disclosure of which is incorporated herein by reference in its entirety. More generally, memoryless DPD circuit block 116 may be implemented using conventional DPD circuits and still provide acceptable memoryless distortion correction due to the more tractable nature of such distortion. Such known memoryless DPD circuit implementations for DPD circuit block 116 will not be described in more detail since a variety of different known implementations may be employed as will be appreciated by those skilled in the art. Next the preferred embodiments of memory DPD circuit block 118 will be described. The preferred methods of correcting power amplifier memory effects implemented by memory DPD circuit block 118 involve altering a memoryless model based on a Taylor series expansion. Two embodiments are illustrated in detail that model and correct the frequency dependent behavior associated with the memory of the power amplifier. The first embodiment (described in detail below in relation to FIGS. 5 and 6) transforms even-order nonlinear sub-signals into a joint time-frequency representation. The transformed even-order sub-signals are then used to re-modulate the input signal, producing the desired odd-order correction. The first embodiment has the benefit of achieving the memory correction using a low number of coefficients. The second embodiment (described in detail below in relation to FIGS. 11 and 12) transforms odd-order nonlinear sub-signals into a joint time-frequency representation, increasing the number of coefficients available for tuning. First the general principles of operation generally underlying both embodiments of memory DPD circuit block 118 will be described. A time-frequency representation based on time-shifted and frequency-modulated Gaussian functions, referred to as a Gabor expansion, is used to illustrate the theory of operation. (See, D. Gabor, “Theory of communication,” J. IEE, vol. 93, pp. 429-459, 1946, the disclosure of which is incorporated herein by reference.) The approaches described herein can use any type of time-frequency representation, formed by time-shifting and frequency-modulating other types of window functions (for example, Hanning or raised cosine windows). In the preferred embodiments, the input signal is not transformed or sub-divided in any manner; the time-frequency expansions are applied only to the nonlinear modes derived from the input signal that generate the correction signal, xDPD(nT). A RF signal, xNL(t), at the output of a memoryless nonlinear device such as amplifier 110 can be modeled by an odd-order Taylor series: x NL ( t ) = ∑ k = 0 m a 2 k + 1 • x ( t ) 2 k • x ( t ) ( Eq . 1 ) where ak are complex coefficients and x(t) is the RF input signal. The memoryless model within (Eq. 1) assumes the nonlinear modes are functions of the instantaneous input value, x(t), only. In contrast, for a power amplifier exhibiting memory effects, the nonlinear modes are functions of both instantaneous and past input values. However, when the input signal is bandlimited, the basis functions used to model either |x(t)|2k or |x(t)|2kx(t) can be modified to compensate for the effects of power amplifier memory. An input signal, x(t), derived from a time-sampled sequence, x(nTh), is bandlimited: that is, x ( t ) = ∑ n x ( nT h ) • h ( t - nT h ) ( Eq . 2 ) where h(t) is a bandlimited interpolation function and Th is the sampling interval. It is possible to create a joint time-frequency sampled representation of the input signal, referred to as a Gabor expansion, using a weighted sum of time-shifted and frequency-modulated Gaussian functions. (See D. Gabor, “Theory of communication,” as referenced above.) The Gaussian function, denoted by g(t), is g(t)=exp(−α·t2) (Eq. 3) where α is a positive constant. It has a Gaussian shape in both the time and frequency domains as shown in FIGS. 2A-2C. FIGS. 2A and 2B show the time-shifted and frequency-modulated Gaussian function in the time and frequency domains, respectively, and FIG. 2C illustrates the combined time and frequency domain representation. It should be noted that the temporal standard deviation 202 of the time domain Gaussian function 200 (FIG. 2A) and the frequency standard deviation 206 of the Gaussian function 204 (FIG. 2B), cannot be chosen independently (that is, ΔtΔω=constant). (See D. Gabor, “Theory of communication,” as referenced above). The Gabor expansion is x ( t ) = ∑ q ∑ n y q ( nT ) • g ( t - nT ) • exp ( j q • Ω • t ) ( Eq . 4 ) where q is an integer; T and Ω are the sample intervals within the time and frequency domains, respectively. This joint time-frequency sampled representation partitions the spectrum of the input sequence into Nq overlapping frequency bands. The samples for the time series in (Eq. 2) and the Gabor expansion in (Eq. 4) are shown in FIG. 3A-3B. FIG. 3A illustrates sampling locations 300 for a time series and FIG. 3B illustrates sampling locations 302 for a joint time-frequency representation. It should be appreciated that the temporal sampling interval in the Gabor expansion, T, is not the same as the original sampling interval, Th. To preserve the number of independent samples, the former should be longer by a factor equal to the number of frequency samples (that is, T=Th*Nq). As a convention, the temporal and frequency sampling intervals are 1.4 times the respective standard deviations of the Gaussian envelope. As a consequence, the temporal sampling interval and temporal width of the Gaussian both increase with the number of frequency samples. This is significant because the quality of the DPD correction is determined by the temporal width of the Gaussian relative to the delay introduced by the memory effect (see later (Eq. 13)). The samples of the Gabor expansion, yq(nT), are obtained using a known transformation from the input sequence x(nTh). The transformation accounts for overlaps in the time-shifted, frequency-modulated Gaussians, as well as the original interpolation function, h(t). Replacing the Gaussian function with an alternative window creates similar types of joint time-frequency expansions. The Gaussian, which makes the mathematics more tractable, is shown for illustrative purposes. In practice, the Gaussian function is not used because it has an infinite extent in the time domain (approaches zero asymptotically). A Hanning window or a raised cosine window can be used instead to build the time-frequency representation with similar success. In addition, the joint time-frequency representation can be achieved using a bank of filters instead of an expansion. Although the filter bank does not explicitly account for overlaps between non-orthogonal kernels, the effect is similar to changing the window function. That is, a filter bank of Gaussians functions, g(t), is the same as an expansion using a bi-orthogonal function, gb(t). (See, M. J. Bastiaans, “Gabor's expansion of a signal into Gaussian elementary signals,” Proc. IEEE, vol. 68, pp. 538-539, 1980, and M. J. Bastiaans, “A sampling theory for the complex spectrogram, and Gabor's expansion of a signal in Gaussian elementary signals,” Optical Eng., vol. 20, no. 4, pp. 594-598, 1981, the disclosures of which are incorporated herein by reference). The bi-orthogonal relationship between g(t) and gb(t) is defined by ∫g(t−kT)·gb(t−mT)dt=1 when k=m (Eq. 5) ∫g(t−kT)·gb(t−mT)dt=0 when k≠m. (Eq. 6) In summary, the filter bank and the joint time-frequency expansion are equally suitable representations for memory compensation. After the above general discussion of the underlying theory of operation, next the principles of operation of the first embodiment of the memory DPD circuit block 118 of the present invention will be described. A third-order nonlinearity may be written using (Eq. 4) to represent the |x|2 term: x ( t ) • x ( t ) 2 = x ( t ) • ∑ L ∑ k z L ( kT 2 ) • g 2 ( t - kT 2 ) • exp ( j L • Ω • t ) ( Eq . 7 ) where L=q1−q2, k=n1+n2, and z L ( kT 2 ) = ∑ n ( 1 ) ∑ n ( 2 ) [ y q ( 1 ) ( n 1 T ) y q ( 2 ) * ( n 2 T ) ] • exp { - α • Δ n 2 T 2 2 } ( Eq . 8 ) g2(t)=[g(t)]2 (Eq. 9) Δn2=(n1−n2)2. (Eq. 10) From (Eq. 7), it can be seen that the power envelope comprises a weighted sum of frequency-offset basis functions: β 2 ( kT , L Ω ) = g 2 ( t - kT 2 ) • exp ( j L • Ω • t ) . ( Eq . 11 ) Compensation of memory effects is achieved by re-shaping the basis functions used within the nonlinear mode models. The simplest modification is to delay the Gaussian window g2 by an offset, δτ. The effect of a time shift, δτ, on the basis function β2(kT,LΩ) is shown in FIG. 4. In FIG. 4 the original basis function is illustrated at 400 and, after a small time shift 402, the shifted basis function is illustrated at 404. For small delays, the change in the basis function is approximated by a phase shift: that is, β2(kT+δT,LΩ)≈β2(kT,LΩ)·exp(jL·Ω·δτ). (Eq. 12) The quality of the memory compensation is determined by the correlation between β2(kT,LΩ) and β2(kT+δτ,LΩ), which is dependent largely on the width of the Gaussian and the size of the delay. The correlation, ρ, should be close to unity for good memory compensation: that is, ρ=g4(δτ)≈1. (Eq. 13) The phase offset term, LΩδτ, can be incorporated into the coefficients of the Taylor series model: from (Eq. 1), (Eq. 7), (Eq. 11) and (Eq. 12), we get x NL ( t ) = x ( t ) + x ( t ) • ∑ L c 2 , L ∑ k z L ( kT 2 ) • β 2 ( kT , L Ω ) ( Eq . 14 ) where the coefficients c2,L are c2,L=a3·exp(jL·Ω·δτ). (Eq. 15) A least mean squared (LMS) estimator is preferably used to calculate the coefficients that best correct the power amplifier memory effects. It is possible to implement the third-order correction using (Eq. 7) and (Eq. 8) implemented directly in a suitably programmed DSP or arithmetic operation circuit implemention of circuit block 118. However, in such an implementation the transformation from x(nTh) to yq(nT) is required which will generally require too much processing power or arithmetic operations to be a practical cost effective embodiment. The preferred implementations of circuit block 118 instead use filter banks to create the joint time-frequency representation, as shown in two separate implementations in FIG. 5 and FIG. 6. In the implementation of FIG. 5, filtering is applied before the nonlinear operation, ∥2. In the implementation of FIG. 6, filtering is applied after the nonlinear operation, ∥2. More specifically, referring to FIG. 5 the input signal is provided along a first signal path comprising a delay 500. The input signal is also applied to a second path where it is provided to a filter bank comprising first and second filters 502 and 504 which create the joint time-frequency representation from the input signal, using Gaussian functions g(t) as described above, and split the input signal into two band limited components (denoted A and B) provided along lines 506 and 508. (As used herein, band limited includes high pass or low pass bands as well as strict limiting to a defined band.) The frequency bands passed by filters 506 and 508 will be chosen based on the spectral characteristics of the input signal and the expected nonlinear modes generated by the power amplifier or the spectral mask for the specific cellular application. The filters may therefore have fixed filter coefficients simplifying the implementation of the circuitry. Filters 502 and 504 have different frequency responses and filter 504 is illustrated with a frequency response which is the image of filter 502. The two components A and B are provided to three separate signal paths 510, 512 and 514 comprising respective nonlinear operation circuits which create higher order signals from the band limited signals A and B. In these signal paths auto- and cross-terms are preferably computed producing sub-sequences concentrated in three different parts of the spectrum. More specifically, in signal path 510 the complex conjugate of the signal B is computed at 518 and multiplied with the signal A at complex multiplying circuit 516. In signal path 512, the signals A and B are provided to circuits 522 and 524, respectively, which compute the magnitude squared of the respective signals, which are then added at addition circuit 526. In signal path 514, the input signal A is provided to complex conjugate circuit 530, which is then multiplied with the signal B at complex multiplication circuit 532. By applying complex weights to the sub-sequences, at weighting circuits 520, 528 and 534, the frequency response becomes adjustable, which in turn provides the capability for selectively compensating for memory effects. (The subscripts of the coefficients indicate the order of the nonlinear mode and the frequency response respectively.) The coefficients to the weighting circuits 520, 528, and 534 may be selected (referred to as “selective weighting”) so that the corrected output signal has the maximum margin relative to the spectral mask (the amount that the corrected PA output spectrum is below the spectral mask specification), the minimum distortion outside of the bandwidth of the linear signal, or minimum distortion power, and such weighting may be adaptively provided as described herein. For the first two criteria, the cross-term sub-sequences provided on signal paths 510 and 514 tend to be the most important for the purpose of memory correction because the important spectral regrowth occurs outside of the original linear signal bandwidth. The respective weighted subsequences are combined at addition circuit 538 and addition circuit 536. The combined weighted subsequences are then multiplied with the delayed input signal at complex multiplication circuit 542 to create a third order signal and provide the output as the memory digital predistortion correction signal on line 544. In the embodiment of FIG. 6, the input signal is provided along a first signal path comprising delay circuit 600. The input signal is also provided along a second signal path to nonlinear operation circuit 602, which computes the magnitude squared of the input signal. The magnitude squared signal is then provided to a filter bank comprising first filter 604, second filter 606 and third filter 608. The filters 604, 606 and 608 create the joint time-frequency representation using squared Gaussian functions, in this case after the nonlinearity provided by circuitry 602, to create the desired sub-sequences which are band limited signals. The sub-sequences are then provided to weighting circuits 610, 612 and 614 which weights the subsequences with the appropriate complex weighting coefficients. The weighted subsequences are then provided to complex addition circuit 618 and 616 and then provided to multiplying circuit 622. The delayed input signal is multiplied with the weighted subsequences at complex multiplying circuit 622 to provide the third order digital predistotion correction signal along line 624. The DPD operations of the two implementations shown in FIG. 5 and FIG. 6 differ because the overlap between the non-orthogonal filters 1 and 2 within FIG. 5 is not accounted for within FIG. 6. However, the outer filters in FIG. 6, which are the most important, are the least affected. When comparing the post-filtering implementation shown in FIG. 6 with the Gabor expansion, (Eq. 7) and (Eq. 8), it can be seen that zL(mT) is replaced by |x(mT)|2. As mentioned earlier, a bank of filters is equivalent to an expansion using a bi-orthogonal window (see M. J. Bastiaans, “Gabor's expansion of a signal into Gaussian elementary signals,” Proc. IEEE, vol. 68, pp. 538-539, 1980, M. J. Bastiaans, “A sampling theory for the complex spectrogram, and Gabor's expansion of a signal in Gaussian elementary signals,” Optical Eng., vol. 20, no. 4, pp. 594-598). In either case, the memory effects are cancelled; however, the filter bank benefits from ease of implementation. Also, it should be appreciated that a number of modifications may be made which may involve trade offs between circuit complexity and effectiveness of the correction. For example, additional filters may be provided in the respective filter banks and additional nonlinear operation circuits may be provided, providing higher than third order signals if desired. Higher order compensation can be achieved by modifying the memory compensation shown FIG. 5 or FIG. 6. By modulating the output signal of the memory DPD, either 544 or 624, by an even-order mode of the input signal (delayed appropriately) 732, the order of the correction is increased. For example, modulating by |x|2 produces a fifth-order correction. The higher-order compensation would be implemented, typically, as additional paths parallel to the third-order compensation. The estimator in FIG. 8 would be expanded to include higher-order subsequence calculation circuits, in parallel with 800, whose higher-order subsequences are filtered using hestimator and provided to the coefficient estimate 816. The higher-order subsequences can be modifications of the third-order subsequences, where the outputs 802, 804, and 806 are modulated by the delayed even-order mode of the input signal 732. For the case of the memory compensation shown in FIG. 6, an alternative form of higher-order compensation can be achieved by increasing the order of the nonlinear circuits 602 and 1002. For example, changing the nonlinear circuits 602 and 1002 to |x|4 would provide fifth-order compensation. Referring to FIG. 7 an embodiment of the linearized power amplifier system of the present invention implying adaptive generation of digital predistotion coefficients is illustrated. In the previous embodiment of FIG. 1 the predistortion coefficients may be modeled in advance for the specific application. In the illustrated embodiment of FIG. 7 the predistortion coefficients may be adaptively calculated using the above described theory and the digital predistortion coefficients may be computed as the system operates to minimize error and maximize the linearity of the overall system. More specifically, as shown in FIG. 7 an input signal is provided at input 700 which as in the previously described embodiment is preferably a complex digital signal having in phase and quadrature components. The signal is provided to digital predistorter 702 which predistorts the input signal to compensate for nonlinearity introduced by the transmitter 704. The implementation of digital predistorter 702 may correspond to circuit 100 described above with however the predistortion coefficients being adaptively generated as described below. The predistorted output of the digital predistorter 702 is provided to transmitter 704 which may comprise conventional circuitry including digital to analog converter 710, up converter 712 and power amplifier 714. As in the previously described embodiment the digital predistorter 702 may compensate for nonlinearity of the power amplifier 714 and optionally nonlinearity introduced by other nonlinear circuitry in transmitter 704. The output of the power amplifier 714 is provided as a generally nonlinear RF output signal in analog form at output 708. This output signal is also sampled by sampling coupler 706 which provides an analog sampled output signal to a feedback (or observation) path used to adaptively generate digital predistotion coefficients. More specifically, the sampled analog output from sampling coupler 706 is first provided to a gain adjusting circuit 716 which provides a suitable adjustment to the sampled signal to normalize the signal for appropriate processing by subsequent circuitry as described below. The gain adjusted sampled analog RF output signal is then provided to down converter 718 which converts the sampled RF output signal to a suitable intermediate or baseband frequency for subsequent processing. The down converted signal is then provided to analog to digital converter (ADC) 720 which samples the analog signal to convert the frequency down converted analog signal to digital form. The output of analog to digital converter 720 thus comprises a digital sampled version of the output signal 708 in the same format as the input signal, i.e. preferably a complex in phase and quadrature digital signal. (As linear operations, the order in which the normalization, down-conversion, and sampling is applied can be changed, or distributed over stages.) This digital sampled output signal is provided to inverter 722 and then to complex addition circuit 726 to collectively implement a subtraction operation. Complex addition circuit 726 also receives a delayed version of the digital input signal provided by delay circuit 724 to compensate for the delay introduced by the DPD 734, transmitter 704, and feedback circuitry 706, 716, 718, 720 and 722 so that the delayed input signal (or sequence of signals) from circuit 724 corresponds to the same signal presented at the output of circuit 722. The output of the complex addition circuit 726 represents an error signal between the input and output signals due to the nonlinearity of power amplifier 714. This error signal is provided along line 728 to adaptive coefficient generator circuit 730. The circuit 730 also receives a copy of the delayed input signal along line 732 and using the error signal and input signal generates new digital predistotion coefficients which are then provided to digital predistorter 702 along line 734. This allows the system to adapt to changing conditions and create new predistotion coefficients adapted for the current operating conditions of the system. This may preferably be done on a batch processing basis and the adaptive coefficient generator 730 may implement the desired adaptive processing using a suitably programmed digital signal processor or other processor. Adaptive coefficient generator 730 preferably provides updated digital predistotion coefficients for both the memoryless and memory based digital predistortion circuitry (116 and 118, shown in FIG. 1). The adaptive updating of the memoryless coefficients will correspond to the specific memoryless digital predistortion implementation. For example, in a look up table approach the adaptive coefficient generator 730 will generate suitable updated look up table coefficients from the error signal to minimize the error and hence minimize the distortion in the output signal. A specific implementation of such an adaptive look up table system is described in the above mentioned U.S. patent application Ser. No. 10/818,547 filed Apr. 5, 2004, the disclosure of which is incorporated herein by reference in its entirety. Accordingly, the details of such an adaptive look up table coefficient generator for adaptive updating of the memoryless coefficients will not be described in more detail herein. Specific implementations of adaptive coefficient generator 730 for memory DPD coefficients will be described below in relation to FIGS. 8 and 13. Before describing detailed implementations of adaptive coefficient generator 730 for memory coefficient generation, the basic theory employed will be described. The generation of updated coefficients for the memory digital predistortion circuitry may incorporate the previously described theory of operation in the circuitry 730 to update the coefficients. More specifically, using the model of (Eq. 14) gives the adaptive coefficient generator 730 the ability to compensate (partially) for memory effects without modeling them explicitly. Thus, significant correction of memory effects can be provided when the temporal width of g2 is large enough to keep p near unity (see (Eq. 13)). Larger temporal widths of g2 may be achieved by increasing the number of frequency bands Nq used in the Gabor expansion or filter bank. The coefficients may be computed using a weighted least mean square (LMS) estimation. The sampled error signal provided along line 728 is determined as follows: ε(mT)=xNL(mT)−x(mT) (Eq. 16) where as described above the output signal xNL(mT) has been normalized, down-converted, and sampled by the illustrated feedback circuitry shown in FIG. 7, and input signal x(mT) has been delayed such that the two sequences have the same nominal gain, phase, and alignment in time. The error sequence, ε(mT), has the same sampling rate as the forward path sequence (assumed to be oversampled by at least a factor of 3, see discussion below). The third-order sub-sequences, derived from the input signal, are γ(mT,LΩ)=x(mT)·zL(mT)·β2(mT,LΩ). (Eq. 17) The power amplifier model, referenced to the digital portion of the system, is written as ɛ ( mT ) = ∑ L c 2 , L • γ ( m , T , L Ω ) . ( Eq . 18 ) A direct LMS estimation for the three-coefficient case of (Eq. 18) is described below. Measurements are accumulated over a time interval [mT−moT,mT]. Assuming that the memory DPD has partially corrected the memory effect, the error in the coefficients, denoted by Δc2L, are computed using Δc2,L=[γv·γvT]−1·γv·εv (Eq. 19) where εv[ε(mT−moT) . . . ε(mT)]T, and γ v = [ γ ( mT - m o T , - 2 Ω ) ⋯ γ ( mT , - 2 Ω ) γ ( mT - m o T , 0 ) ⋯ γ ( mT , 0 ) γ ( mT - m 0 T , 2 Ω ) ⋯ γ ( mT , 2 Ω ) ] . ( Eq . 20 ) The coefficients are updated in an iterative manner using c2,L(k+1)=c2,L(k)−λ·Δc2,L(k) (Eq. 21) where k is the iteration counter and λ is a convergence constant (0<λ<=1). One potential problem with the direct implementation of the LMS estimator is that the compensation favors portions of the spectrum with large error power. Unfortunately, this corresponds, typically, to the bandwidth spanning the linear signal. In general, distortion in this area is not of significant importance because it is masked by the linear signal. In contrast, spectral regrowth outside the linear signal bandwidth is important and needs to be minimized. Typically constraints on such distortion outside the signal bandwidth (or spectral mask) are much more stringent than within the bandwidth due to government regulations of wireless carriers. To reduce the influence of the error located within the linear signal bandwidth, the error sequence and the third-order sub-sequences are preferably modified using a linear operation, such as a filter. Since the coefficients are constants, a linear operator, denoted by flinear( ), can be applied to each third-order sub-sequences separately (exploiting superposition, see FIG. 8): that is, f linear { ɛ ( mT ) } = ∑ L Δ c 2 , L • f linear { γ ( mT , L Ω ) } . ( Eq . 22 ) An example of a linear operation is an FIR (Finite Impulse Response) filter whose kernel, hestimator(mT), preferably notches the linear signal response and highlights the critical portion of the spectrum (as specified by the relevant standards): f linear { ɛ ( mT ) } = ∑ k ɛ ( kT ) · h estimator ( mT - kT ) . ( Eq . 23 ) Other linear operations, such IIR filters, can also be used in (Eq. 22). Thus, to improve the distortion cancellation in a specific portion of the spectrum, the following are substituted into (Eq. 19): εv=[ƒlinear{ε(mT−moT}. . . ƒlinear{ε(mT)}]T (Eq. 24) and γ v = [ f linear { γ ( mT - m o T , - 2 Ω ) } … f linear { γ ( mT , - 2 Ω ) } f linear { γ ( mT - m o T , 0 ) } … f linear { γ ( mT , 0 ) } f linear { γ ( mT - m o T , 2 Ω ) } … f linear { γ ( mT , 2 Ω ) } ] . ( Eq . 25 ) Referring to FIG. 8, a preferred embodiment of the adaptive coefficient generator 730 is illustrated adapted for updating the coefficients of the memory DPD circuit using the above described theory of coefficient calculation. More specifically, as shown in FIG. 8, the adaptive coefficient generator 730 receives the input signal appropriately delayed along line 732 and the normalized error signal along line 728. The input signal along line 732 is provided to a third-order mode subsequence calculation circuit 800. The third-order mode subsequence calculation circuit 800 has a structure similar to the memory DPD circuit 118 (of FIG. 1), third-order examples of which are shown in FIG. 5 and FIG. 6 described above. (The third-order mode subsequence calculation circuit 800 used with the pre-filtering implementation (FIG. 5) is shown in FIG. 9, described below. The third-order mode subsequence calculation circuit 800 used with the post-filtering implementation (FIG. 6) is shown in FIG. 10, described below.) The third-order sub-sequences, derived from the input signal, are provided along lines 802, 804 and 806 to filters 808, 810, and 812. As noted above filters 808, 810, and 812 may preferably be FIR (Finite Impulse Response) filters whose kernel, hestimator(mT), preferably notches the linear signal response and highlights the critical portion of the spectrum (as specified by the relevant standards). The outputs of filters 808, 810, and 812 are provided to coefficient estimator 816. Coefficient estimator 816 also receives an input corresponding to the error signal along 728 filtered by filter 814 which should correspond to filters 808, 810 and 812 and also may preferably be a FIR filter with appropriately chosen kernel. Coefficient estimator 816 then computes the error in the coefficients using equation (19) above. For example, coefficient estimator 816 may be a suitably programmed DSP which implements equation (19) or may be a hardware arithmetic circuit implementation. Also, if a DSP implementation is chosen the other functional blocks in FIG. 8 may also be suitably implemented as software in the DSP. Since, as noted above, the operation of the adaptive coefficient generator 730 may be in a batch processing mode the DSP functionality may be easily shared with other functions. The coefficient error computed by the coefficient estimator 816 is output on line 734 as illustrated and used to update the coefficients employed in the memory DPD circuitry as described above in relation to FIG. 7. Referring to FIG. 9, a first preferred embodiment of the third-order mode subsequence calculation circuit 800 is illustrated. As shown, the circuit 800 receives the input signal along line 732 and provides it along a first path including delay circuit 900. The input signal is also provided along a second path to a filter bank comprising first filter 902 and second filter 904. These filters may implement the same functional operations as the filters described previously in relation to FIG. 5. More specifically first filter 902 and second filter 904 have different fixed frequency responses (such as images of each other) and split the input signal into two band limited components (denoted A and B) provided along lines 906 and 908. The two components A and B are provided to three separate signal paths 910, 912 and 914 comprising nonlinear operation circuits. In these signal paths auto- and cross-terms are computed producing sub-sequences concentrated in three different parts of the spectrum. More specifically, in signal path 910 the complex conjugate of the signal B is computed at 918 and multiplied with the signal A at complex multiplication circuit 916. In signal path 912, the signals A and B are provided to circuits 922 and 924, respectively, which compute the magnitude squared of the respective signals, which are then added at addition circuit 926. In signal path 914, the input signal A is provided to complex conjugate circuit 930, the output of which is then multiplied with the signal B at complex multiplication circuit 932. The subsequences generated in signal paths 910, 912 and 914 are then combined with the delayed input signal D to generate the third-order sub-sequences illustrated in FIG. 8 provided along lines 802, 804 and 806. More specifically, the output of the signal path 910 is combined at complex multiplication circuit 934 with the delayed input signal D on line 936 to generate the third order subsequence provided along line 802. The output of signal path 912 is provided to complex multiplication circuit 938 and multiplied with the delayed input signal D provided along line 940 to generate the third order subsequence provided on line 804. The output of signal path 914 is provided to complex multiplication circuit 942 and multiplied with the delayed input signal D provided along line 944 to generate the third order subsequence on line 806. As noted above in relation to FIG. 8, the circuitry illustrated in FIG. 9 may be implemented in a suitably programmed DSP due to the batch mode processing of the coefficient update processing whereas the corresponding circuitry of FIG. 5 is preferably implemented in hardware, such as an ASIC or FPGA circuit, in order to provide the real-time DPD processing. Referring to FIG. 10, a second embodiment of the third-order mode subsequence calculation circuit 800 is illustrated. As shown, the circuit 800 receives the input signal along line 732 and provides it along a first path including delay circuit 1000. The input signal is also provided along a second path to nonlinear operation circuit 1002, which computes the magnitude squared of the input signal. The magnitude squared signal is then provided to a filter bank comprising first filter 1004, second filter 1006 and third filter 1008. The filters 1004, 1006 and 1008 create the desired band limited sub-sequences and these filters may implement the same functional operations as the filters described previously in relation to FIG. 6. The sub-sequences are then provided to respective combining circuits and combined with the delayed input signal D to generate the third-order sub-sequences illustrated in FIG. 8 provided along lines 802, 804 and 806. More specifically, the output of the first filter 1004 is provided to complex multiplication circuit 1010 and multiplied with the delayed input signal D provided along line 1012 to generate the third order subsequence provided on line 802. The output of the second filter 1006 is provided to complex multiplication circuit 1014 and multiplied with the delayed input signal D provided along line 1016 to generate the third order subsequence provided on line 804. The output of the third filter 1008 is provided to complex multiplication circuit 1018 and multiplied with the delayed input signal D provided along line 1020 to generate the third order subsequence provided on line 806. Next the second embodiment of memory DPD circuit 118, which transforms odd-order nonlinear sub-signals into a joint time-frequency representation, will be described. First the theory of operation of the memory effect compensation in the second embodiment of memory DPD circuit 118 will be described (specific implementations will be described in detail below in relation to FIGS. 11 and 12). Consider a third-order nonlinearity written using (Eq. 4) for both |x(t)|2 and x(t): x ( t ) · x ( t ) 2 = ∑ L ∑ k z L ( kT 3 ) · g 3 ( t - kT 3 ) · exp ( j L · Ω · t ) ( Eq . 26 ) where L=q1+q2−q3, k=n1+n2+n3, and z L ( kT 3 ) = ∑ n ( 1 ) ∑ n ( 2 ) ∑ n ( 3 ) [ y q ( 1 ) ( n 1 T ) y q ( 2 ) ( n 2 T ) y q ( 3 ) * ( n 3 T ) ] · exp { - α · Δ n 2 T 2 3 } ( Eq . 27 ) g3(t)=[g(t)]3 (Eq. 28) Δn2=(n1−n2)2+(n1−n3)2+(n2−n3)2. (Eq. 29) From (Eq. 26), it can be seen that the third-order term comprises the weighted sum of frequency-offset basis functions: β 3 ( kT , L Ω ) = g 3 ( t - kT 3 ) · exp ( j L · Ω · t ) . ( Eq . 30 ) Note the sub-sequence zL(kT/3) is oversampled by a factor of 3 relative to the original sequence yq(nT). The requirement for oversampling by a factor of 3 or more is not explicit within the first embodiment described above in relation to FIGS. 5 and 6; however, the 3 times oversampling is preferred once the power envelope is remodulated with the linear signal. For the filter bank implementation, the oversampling by 3 is also provided, preferably at the input. As was the case for first embodiment, the time shift associated with memory effects alters each basis function, primarily, by a phase shift: that is, β3(kT+δτ,LΩ)≈β3(kT,LΩ)·exp(jL·Ω·δτ). (Eq. 31) The phase offset term, LΩδτ, can be incorporated into the coefficients of the Taylor series: from (Eq. 1), (Eq. 26), (Eq. 30), and (Eq. 31), we get x NL ( t ) = x ( t ) + ∑ L c 3 , L ∑ k z L ( kT 3 ) · β 3 ( kT , L Ω ) ( Eq . 32 ) where the coefficients c3,L are c3,L=a3·exp(jL·Ω·δτ). (Eq. 33) As in the first embodiment, the second embodiment can be implemented in three different ways. Specifically, the second embodiment can be implemented as follows: (1) directly using (Eq. 26) and (Eq. 27) in a suitably implemented circuit or high speed DSP; (2) by pre-filtering to split the input signal into components then computing the third-order products; or (3) by post-filtering after applying the nonlinear operation on the input signal (i.e., |x|2x). As was the case in the first embodiment, the direct implementation approach (1) is straightforward to implement but is not preferred due to the complexity of the processing involved. The second implementation is illustrated in FIG. 11 and the third implementation is illustrated in FIG. 12. Referring to FIG. 11 a specific embodiment of the above noted second implementation of memory DPD circuitry 118 is shown. As generally noted above this implementation employs pre-filtering to split the input signal into band limited components and then the third-order products are computed. More specifically, as shown in FIG. 11 the input signal is provided to a filter bank comprising first and second filters 1100 and 1102 which create the joint time-frequency representation of the input signal, using Gaussian functions g(t) as described above, and split the input signal into two band limited components (denoted A and B) provided along lines 1104 and 1106. As in the first embodiment the frequency bands passed by filters 1100 and 1102 will be chosen based on the spectral characteristics of the input signal and the expected nonlinear modes generated by the power amplifier or the spectral mask for the specific cellular application. Also, as before the two filters have different frequency responses, which may be image frequency responses as illustrated. The two band limited components A and B are provided to four separate signal paths 1108, 1110, 1112 and 1114 comprising nonlinear operation circuits. In these signal paths third order nonlinear sub-sequences concentrated in different parts of the spectrum are generated. More specifically, in signal path 1108 the magnitude squared of signal A is computed at circuit 1118 and the complex conjugate of the signal B is computed at circuit 1116 and the resulting signals are multiplied at complex multiplying circuit 1120 to create a third order subsequence which is applied to weighting circuit 1136. In signal path 1110 the signals A and B are provided to circuits 1122 and 1124, respectively, which compute the magnitude squared of the respective signals, which are then added at addition circuit 1126. The output of addition circuit 1126 is then applied to complex multiplication circuit 1128 and multiplied with the signal A to create a third order subsequence which is applied to weighting circuit 1138. In signal path 1112 the output of addition circuit 1126 is applied to complex multiplication circuit 1130 and multiplied with the signal B to create a third order subsequence which is applied to weighting circuit 1140. In signal path 1114, the magnitude squared of signal B is computed at circuit 1134 and the complex conjugate of the signal A is computed at circuit 1132 and the resulting signals are multiplied at complex multiplying circuit 1135 to create a third order subsequence which is applied to weighting circuit 1142. By applying complex weights to the sub-sequences, at weighting circuits 1136, 1138, 1140 and 1142, the frequency response becomes adjustable, which in turn provides the capability for selectively compensating for memory effects. The coefficients to the weighting circuits 1136, 1138, 1140, and 1142 may be selected (referred to as “selective weighting”) so that the corrected output signal has the maximum margin relative to the spectral mask (the amount that the corrected PA output spectrum is below the spectral mask specification), the minimum distortion outside of the bandwidth of the linear signal, or minimum distortion power, and such weighting may be adaptively provided as described herein. For the first two criteria, the cross-term sub-sequences provided on signal paths 1108 and 1114 tend to be the most important for the purpose of memory correction because the important spectral regrowth occurs outside of the original linear signal bandwidth. The respective weighted subsequences are combined at addition circuits 1148, 1146 and 1144 to provide the memory DPD correction along line 1150. Referring to FIG. 12 another specific implementation of the above described second embodiment of memory DPD circuitry 118 is shown. As generally noted above this implementation employs post-filtering after applying the nonlinear operation on the input signal (i.e., |x|2x). More specifically, as shown in FIG. 12 the input signal is provided to nonlinear operation circuit 1200 which creates a third order signal from the input signal by performing the operation |x|2x. The output signal from circuit 1200 is provided to a filter bank comprising filters 1202, 1204, 1206, and 1208. These filters implement a band limiting operation on the third order signal from circuit 1200 and also provide the Gaussian weighting to the third order signal with different frequency responses as indicated. The outputs of filters 1202, 1204, 1206 and 1208 thus comprise third order subsequences which are band limited based on the spectral characteristics of the input signal and the expected nonlinear modes generated by the power amplifier or the specific spectral mask of the particular cellular application. The outputs of filters 1202, 1204, 1206 and 1208 are provided to respective weighting circuits 1210, 1212, 1214 and 1216 which implement the appropriate weighting coefficients. Preferably these coefficients are chosen to weight the subsequences corresponding to spectral regrowth outside the spectral mask with a higher predistortion accuracy and such weighting may be adaptively provided as described herein. The weighted nonlinear subsequences are then provided from the weighting circuits to combining circuits 1222, 1220 and 1218, preferably comprising complex addition circuits as shown, to provide a memory digital predistortion correction signal along line 1224. As in the case of the first embodiment of the memory DPD circuitry 118 described in relation to FIGS. 5 and 6, the implementations of the second embodiment illustrated in FIGS. 12 and 13 can also be suitably incorporated in an adaptive embodiment corresponding to the power amplifier system of FIG. 7. The adaptive coefficient generator 730 of FIG. 7 will be modified using the above described theory of coefficient calculation for the second embodiment. A specific implementation of the adaptive coefficient generator 730 employed for the adaptive estimation of the coefficients c3,L is shown in FIG. 13. Similarly to the first embodiment, it uses filtering to enhance the accuracy of the estimation within the spectrum of interest and provides increased DPD correction for distortion outside the frequency band of the input signal relative to distortion within the band. Referring to FIG. 13, a specific implementation of the adaptive coefficient generator 730 for the second embodiment of the memory DPD circuitry is shown. The input signal is provided along line 732 (corresponding to the delayed input signal of FIG. 7 described above) to third-order mode subsequence calculation circuit 1300. The third-order mode subsequence calculation circuit 1300 has a structure similar to the circuitry implementing the third-order DPD computation shown in FIG. 11 and FIG. 12. (A specific implementation of the third-order mode subsequence calculation circuit 1300 used with the pre-filtering implementation (FIG. 11) is shown in FIG. 14 described below. A specific implementation of the third-order mode subsequence calculation circuit 1300 used with the post-filtering implementation (FIG. 12) is shown in FIG. 15 described below.) The outputs of the third-order mode subsequence calculation circuit 1300 are provided along lines 1314, 1316, 1318, and 1320 to respective filters 1302, 1304, 1306 and 1308. As in the first embodiment filters 1302, 1304, 1306 and 1308 may preferably be FIR (Finite Impulse Response) filters whose kernel, hestimator(mT), preferably notches the linear signal response and highlights the critical portion of the spectrum (as specified by the relevant standards). The outputs of the filters 1302, 1304, 1306 and 1308 are provided to coefficient estimator circuit 1312. Coefficient estimator 1312 also receives an input corresponding to the error signal along 728 filtered by filter 1310 which also may preferably be a FIR filter with appropriately chosen kernel. Coefficient estimator 1312 then computes the error in the coefficients using equation (19) above. As in the first embodiment, coefficient estimator 1312 may be a suitably programmed DSP which implements equation (19) or may be a hardware implementation. Also, if a DSP implementation is chosen the other functional blocks in FIG. 13 may also be suitably implemented as software in the DSP. The coefficient error computed by the coefficient estimator 1312 is output on line 734 as illustrated and used to update the coefficients employed in the memory DPD circuitry as described above in relation to FIG. 7. Referring next to FIG. 14 an implementation of the third-order mode subsequence calculation circuit 1300 used with the pre-filtering implementation of the memory DPD circuit (FIG. 11) is shown. As shown in FIG. 14 the input signal is provided to a filter bank comprising first and second filters 1400 and 1402 which split the input signal into two band limited components (denoted A and B) provided along lines 1404 and 1406. The operation of filters 1400 and 1402 will correspond to filters 1100 and 1102 (described above in relation to FIG. 11). The two band limited components A and B are provided to four separate signal paths 1407, 1409, 1411, and 1413 which include nonlinear operation circuits. In these signal paths the third order nonlinear sub-sequences provided on lines 1314, 1316, 1318, and 1320 in FIG. 13 are generated from the band limited components A and B. More specifically, in signal path 1407 the magnitude squared of signal A is computed at circuit 1408 and the complex conjugate of the signal B is computed at circuit 1410 and the resulting signals are multiplied at complex multiplying circuit 1412 to create the third order subsequence which is provided along line 1314. In signal path 1409 the signals A and B are provided to circuits 1414 and 1416, respectively, which compute the magnitude squared of the respective signals, which are then added at addition circuit 1418. The output of addition circuit 1418 is then applied to complex multiplication circuit 1420 and multiplied with the signal A to create a third-order subsequence which is provided along line 1316. In signal path 1411 the output of addition circuit 1418 is applied to complex multiplication circuit 1422 and multiplied with the signal B to create a third-order subsequence which is provided along line 1318. In signal path 1413 the magnitude squared of signal B is computed at circuit 1426 and the complex conjugate of the signal A is computed at circuit 1424 and the resulting signals are multiplied at complex multiplying circuit 1428 to create a third order subsequence which is provided along line 1320. As in the first embodiment, the circuitry illustrated in FIG. 14 may be implemented in a suitably programmed DSP due to the batch mode processing of the coefficient update processing whereas the corresponding circuitry of FIG. 11 is preferably implemented in hardware, such as an ASIC or FPGA circuit, in order to provide the real-time DPD processing. Referring next to FIG. 15 an implementation of the third-order mode subsequence calculation circuit 1300 used with the post-filtering implementation of the memory DPD circuit (FIG. 12) is shown. As shown in FIG. 15 the input signal is provided to circuit 1500 which creates a third order signal from the input signal provided along line 732 (FIG. 7) by performing the operation |x|2x. The output signal from circuit 1500 is provided to a filter bank comprising filters 1502, 1504, 1506, and 1508. These filters 1502, 1504, 1506, and 1508 correspond in operation to filters 1202, 1204, 1206 and 1208 described above in relation to FIG. 12 and thus provide as outputs third order subsequences which are band limited based on the spectral characteristics of the input signal and the expected nonlinear modes generated by the power amplifier or the specific spectral mask of the particular cellular application. The outputs of filters 1502, 1504, 1506, and 1508 are provided along lines 1314, 1316, 1318 and 1320 and correspond to the respective outputs of third-order mode subsequence calculation circuit 1300 shown in FIG. 13 employed in the adaptive coefficient estimation operation described previously. Higher order compensation can be achieved by modifying the memory compensation shown FIG. 11 or FIG. 12. By modulating the output signal of the memory DPD, either 1150 or 1224, by an even-order mode of the input signal (delayed appropriately) 732, the order of the correction is increased. For example, modulating by |x|2 produces a fifth-order correction. The higher-order compensation would be implemented, typically, as additional paths parallel to the third-order compensation. The estimator in FIG. 13 would be expanded to include higher-order subsequence calculation circuits, in parallel with 1300, whose higher-order subsequences are filtered using hestimator and provided to the coefficient estimate 1312. The higher-order subsequences can be modifications of the third-order subsequences, where the outputs 1314, 1316, 1318, and 1320 are modulated by the delayed even-order mode of the input signal 732. For the case of the memory compensation shown in FIG. 15, an alternative form of higher-order compensation can be achieved by increasing the order of the nonlinear circuits 1200 and 1500. For example, changing the nonlinear circuits 1200 and 1500 to |x|4x would provide fifth-order compensation. Preferred embodiments of the present invention have been described in relation to specific implementations above. Also, the general theory of operation has been described for the different embodiments. It will be appreciated by those skilled in the art from the theory of operation of the present invention that many variations in the above specific implementations are possible, the variations of which are too numerous to describe in specific detail herein. Accordingly, the present invention should not be limited to the specific implementations described above which are purely illustrative in nature.
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<SOH> BACKGROUND OF THE INVENTION <EOH>In the RF transmission of digital information, sampled data sequences are converted to analog signals and processed, subsequently, by various operations containing unwanted nonlinearities. The primary source of nonlinearity is the power amplifier (PA). Nonlinear behavior of the PA (or other devices) can be compensated using digital predistortion. That is, the correction signal is a sampled sequence applied prior to the PA. The correction signal, denoted by XDPD(nT), is represented as a set of higher-order sub-signals corresponding to nonlinear modes in the transmitter. The nonlinear behaviour of the PA transfer characteristics can be classified as memoryless or memory-based. For a memoryless nonlinear device, the nonlinear modes are functions of the instantaneous input value, x(t), only. In contrast, for a PA exhibiting memory effects, the nonlinear modes are functions of both instantaneous and past input values. In general, memory effects exist in any PA; however, the effect becomes more apparent when the bandwidth of the input signal is large. As a result, the correction of memory effects is becoming increasingly more important as wide bandwidth modulation formats are put in use. Accordingly a need presently exists for a system and method for correcting distortion in power amplifiers and especially distortion due to memory effects.
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<SOH> SUMMARY OF THE INVENTION <EOH>In a first aspect the present invention provides a digital predistorter adapted to receive a digital input signal and output a predistorted digital signal. The digital predistorter comprises an input coupled to receive the digital input signal. A first signal path is coupled to the input and comprises a delay circuit and a combiner circuit coupled to the output of the delay circuit. A second signal path is coupled to the input in parallel with the first signal path and comprises a first digital predistorter circuit providing a first predistortion operation on the input signal. A third signal path is coupled to the input in parallel with the first and second signal path and comprises a second digital predistorter circuit providing a second different predistortion operation on the input signal. The combiner circuit receives and combines the outputs of the first and second digital predistorter circuits with the output of the delay circuit of the first signal path to provide a predistorted digital output signal. In a preferred embodiment the first digital predistorter circuit provides the first predistortion operation modeling memoryless distortion effects employing only a current sample of the digital input signal. The second digital predistorter circuit provides the second predistortion operation modeling memory distortion effects employing plural samples of the digital input signal. The combiner circuit preferably comprises a complex addition circuit. The digital predistorter may further comprise a second combiner circuit, coupled to the outputs of the first and second digital predistorter circuits, and providing a combined output of the first and second digital predistorter circuits to the combiner circuit in the first signal path. The second combiner circuit preferably comprises a complex addition circuit. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion correction signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a first signal path comprising a delay circuit coupled to the input and a combiner circuit coupled to the output of the delay circuit. The digital predistortion circuit further comprises a filter bank, coupled to the input and configured in parallel with the first signal path, comprising at least two filters having different frequency responses and outputting at least first and second band limited signals derived from plural samples of the digital input signal. A plurality of nonlinear operation circuits are coupled to the filter bank and receive the band limited signals, the nonlinear operation circuits creating higher order signals from the band limited signals. The outputs of the nonlinear operation circuits are provided to the combiner circuit in the first signal path and combined with the delayed input signal output from the delay circuit in the first signal path to provide a digital predistortion output signal. In a preferred embodiment the digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the nonlinear operation circuits and applying respective weighting coefficients to the higher order signals. The input signal will have an associated frequency bandwidth and one or more of the higher order signals will fall within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. The combiner circuit preferably is a complex multiplication circuit and the predistortion output signal output from the combiner circuit is a third order signal derived from the input signal and the higher order signals from the nonlinear operation circuits. The digital predistortion circuit may further comprise a plurality of complex addition circuits receiving and adding the higher order signals from the plurality of nonlinear operation circuits and providing the combined higher order signals to the combiner circuit in the first signal path. The filter bank may comprise first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response. The plurality of nonlinear operation circuits may comprise first, second and third nonlinear operation circuits. The first nonlinear operation circuit comprises a first complex conjugation circuit receiving the output of the second filter and a first complex multiplication circuit receiving the output of the first complex conjugation circuit and the output of the first filter and providing a first higher order signal. The second nonlinear operation circuit comprises first and second magnitude squared circuits receiving the outputs of the first and second filter, respectively, and an addition circuit adding the outputs of the first and second magnitude squared circuits and providing the output as a second higher order signal. The third nonlinear operation circuit comprises a second complex conjugation circuit receiving the output of the first filter and a second complex multiplication circuit multiplying the output of the second complex conjugation circuit and the output of the second filter to provide a third higher order signal. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a first signal path comprising a delay circuit coupled to the input and a combiner circuit coupled to the output of the delay circuit. The digital predistortion circuit further comprises a nonlinear operation circuit coupled to the input and configured in parallel with the first signal path and receiving the digital input signal, the nonlinear operation circuit creating a higher order signal from the digital input signal. A filter bank is coupled to the nonlinear operation circuit and receives the higher order signal, the filter bank comprising plural filters having different frequency responses and outputting plural band limited higher order signals derived from plural samples of the higher order signal. The outputs of the filters are provided to the combiner circuit in the first signal path and combined with the delayed input signal output from the delay circuit in the first signal path to provide a digital predistortion output signal. In a preferred embodiment of the digital predistortion circuit the input signal is a complex signal and the nonlinear operation circuit comprises a magnitude squared circuit providing a signal corresponding to the magnitude squared of the complex digital input signal. The digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the plurality of filters and applying respective weighting coefficients to the band limited higher order signals. The input signal will have an associated frequency bandwidth, and one or more of the band limited higher order signals fall within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. The combiner circuit is preferably a complex multiplication circuit and the predistortion output signal output from the combiner circuit is a third order signal derived from the input signal and the band limited higher order signals. The digital predistortion circuit may also further comprise a plurality of complex addition circuits receiving and adding the band limited higher order signals and providing the combined band limited higher order signals to the combiner circuit in the first signal path. The filter bank may comprise first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response, and a third filter having a different frequency response than said first and second filters. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a filter bank comprising at least two filters having different frequency responses and outputting at least first and second band limited signals derived from plural samples of the digital input signal. The digital predistortion circuit further comprises a plurality of nonlinear operation circuits coupled to the filter bank and receiving the band limited signals, the nonlinear operation circuits creating third order or higher order signals from the band limited signals, and one or more combiner circuits receiving and combining the outputs of the nonlinear operation circuits to provide a digital predistortion output signal. In a preferred embodiment the digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the nonlinear operation circuits and applying respective weighting coefficients to the higher order signals. The input signal will have an associated frequency bandwidth and one or more of the higher order signals fall within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more higher order signals within the bandwidth of the input signal. The one or more combiner circuits preferably comprise a plurality of complex addition circuits. The filter bank may comprise first and second filters having a first fixed frequency response and a second fixed frequency response, respectively, the second frequency response comprising the image of the first frequency response. The plurality of nonlinear operation circuits may comprise first, second, third and fourth nonlinear operation circuits. The first nonlinear operation circuit comprises a first complex squaring circuit receiving the output of the first filter, a first conjugation circuit receiving the output of the second filter, and a first complex multiplication circuit receiving the output of the complex squaring circuit and the first complex conjugation circuit and providing a first higher order signal. The second nonlinear operation circuit comprises first and second magnitude squared circuits receiving the outputs of the first and second filter, respectively, an addition circuit adding the outputs of the first and second magnitude squared circuits, and a second complex multiplication circuit multiplying the output of the first filter and the output of the addition circuit and providing the output as a second higher order signal. The third nonlinear operation circuit comprises a third complex multiplication circuit receiving and multiplying the output of the second filter and the output of the addition circuit and providing the output as a third higher order signal. The fourth nonlinear operation circuit comprises a second complex conjugation circuit receiving the output of the first filter, a second complex squaring circuit receiving the output of the second filter, and a fourth complex multiplication circuit multiplying the output of the second complex conjugation circuit and the output of the second complex squaring circuit to provide a fourth higher order signal. According to another aspect the present invention provides a digital predistortion circuit adapted to receive a digital input signal and output a digital predistortion signal compensating for memory effects due to plural samples of the input signal. The digital predistortion circuit comprises an input for receiving the digital input signal. The digital predistortion circuit further comprises a nonlinear operation circuit coupled to the input and receiving the digital input signal. The digital predistortion circuit further comprises a nonlinear operation circuit creating third or higher order signals from the digital input signal. A filter bank is coupled to the nonlinear operation circuit and receives the third or higher order signals, the filter bank comprising plural filters having different frequency responses and outputting plural band limited third order or higher order signals derived from plural samples of the third or higher order signal. The digital predistortion circuit further comprises one or more combiner circuits receiving and combining the outputs of the filters to provide a predistortion output signal. In a preferred embodiment of the digital predistortion circuit the input signal is a complex signal and the nonlinear operation circuit comprises a circuit providing a third order signal corresponding to the magnitude squared of the complex digital input signal multiplied by the complex digital input signal. The digital predistortion circuit may further comprise a plurality of weighting circuits coupled to the outputs of the plurality of filters and applying respective weighting coefficients to the band limited third order or higher order signals. The input signal will have an associated frequency bandwidth, and one or more of the band limited third order or higher order signals fall at least partially within the bandwidth of the input signal. The weighting coefficients apply a selective weighting for the one or more third order or higher order signals within the bandwidth of the input signal. The one or more combiner circuits preferably comprise a plurality of complex addition circuits receiving and adding the band limited third order or higher order signals. The filter bank may comprise first, second, third and fourth filters each having a different fixed frequency response. According to another aspect the present invention provides an adaptive digital predistortion system adapted to receive a digital input signal and output a predistorted digital signal to a nonlinear component and to receive a digital sample of the output of the nonlinear component. The digital predistortion system comprises an input coupled to receive the digital input signal. A digital predistorter module is coupled to the input and comprises a predistortion circuit operating on the digital input signal to create band limited signals from the input signal and employing separate predistortion coefficients for weighting the band limited signals. The digital predistortion system further comprises an error generator circuit for receiving the digital input signal and the digital sample of the output of the nonlinear component and providing a digital error signal. The digital predistortion system further comprises an adaptive coefficient generator, coupled to receive the digital input signal, and the digital error signal and comprising a spectral weighting circuit to derive separately weighted frequency components from the input signal and error signal and a coefficient estimator circuit for calculating updated predistortion coefficients weighted differently for different frequency components and providing the updated predistortion coefficients to the digital predistorter module. In a preferred embodiment of the adaptive digital predistortion system the coefficient estimator circuit comprises a weighted least mean square coefficient estimator. The coefficient estimator circuit preferably comprises a digital signal processor programmed with a weighted least mean square algorithm. The spectral weighting circuit preferably comprises a plurality of digital filters receiving and operating on the digital input signal and the digital error signal. The spectral weighting circuit preferably further comprises a subsequence calculation circuit for deriving frequency limited subsequences from the digital input signal and one of the plurality of digital filters receives and operates on the digital error signal and the remaining ones of the plurality of digital filters receive and operate on the frequency limited subsequences. According to another aspect the present invention provides a linearized amplifier system adapted to receive a digital input signal and output an amplified RF signal. The linearized amplifier system comprises an input coupled to receive the digital input signal. The linearized amplifier system further comprises a digital predistorter module. The digital predistorter module comprises a first signal path coupled to the input, the first signal path comprising a delay circuit and a combiner circuit coupled to the output of the delay circuit. The digital predistorter module further comprises a second signal path, coupled to the input in parallel with the first signal path, comprising a first digital predistorter circuit providing a memoryless predistortion operation on the input signal operating on single samples of the input signal. The digital predistorter module further comprises a third signal path, coupled to the input in parallel with the first and second signal paths, comprising a second digital predistorter circuit providing a memory based predistortion operation on the input signal employing plural samples of the input signal. The combiner circuit of the digital predistorter module receives and combines the outputs of the first and second digital predistorter circuits with the output of the delay circuit of the first signal path to provide a predistorted digital signal. The linearized amplifier system further comprises a digital to analog converter coupled to receive the predistorted digital signal from the digital predistorter module and provide a predistorted analog signal and an up converter receiving the predistorted analog signal from the digital to analog converter and converting it to an RF analog signal. The linearized amplifier system further comprises a power amplifier receiving the RF analog signal and providing an amplified RF output signal. According to another aspect the present invention provides an adaptively linearized amplifier system. The adaptively linearized amplifier system comprises an input coupled to receive a digital input signal. The adaptively linearized amplifier system further comprises a digital predistorter module coupled to the input and receiving the digital input signal and outputting a predistorted digital signal. The digital predistorter module comprises a predistortion circuit operating on the digital input signal to create band limited signals from the input signal and employing separate predistortion coefficients for weighting the band limited signals. The adaptively linearized amplifier system further comprises a digital to analog converter coupled to receive the predistorted digital signal output of the digital predistorter module and provide an analog signal and an up converter for receiving the analog signal from the digital to analog converter and converting it to an RF analog signal. The adaptively linearized amplifier system further comprises a power amplifier receiving the RF analog signal and providing an amplified RF output signal. An output sampling coupler is coupled to sample the analog RF output signal from the power amplifier. The adaptively linearized amplifier system further comprises a feedback circuit path, coupled to the output sampling coupler, comprising a down converter and an analog to digital converter converting the sampled RF output signal to a digital sampled signal representative of the RF output signal. The adaptively linearized amplifier system further comprises an error generator circuit coupled to the input and the feedback circuit path for receiving the digital input signal and the digital sampled signal and providing a digital error signal. The adaptively linearized amplifier system further comprises an adaptive coefficient generator, coupled to receive the digital input signal and the digital error signal, and providing updated predistortion coefficients to the digital predistorter module. The adaptive coefficient generator comprises a spectral weighting circuit to derive separately weighted frequency components from the digital input signal and digital error signal and a coefficient estimator circuit for calculating updated predistortion coefficients weighted differently for different frequency components. According to another aspect the present invention provides a method for digitally predistorting a digital input signal. The method comprises receiving a digital input signal and splitting the digital input signal along three parallel signal paths. The method further comprises delaying the signal provided along the first signal path. The method further comprises digitally predistorting the signal provided along the second signal path employing a single sample of the input signal to provide a memoryless predistortion correction. The method further comprises digitally predistorting the signal along the third signal path employing plural samples of the input signal to provide a memory based digital predistortion correction. The method further comprises combining the memoryless and memory based digital predistortion corrections provided from the second and third signal paths with the delayed signal in the first signal path to provide a predistorted digital output signal. According to another aspect the present invention provides a method for digitally predistorting a digital input signal. The method comprises receiving a digital input signal and deriving a plurality of band limited higher order signals from the digital input signal. The method further comprises weighting the plurality of band limited higher order signals with predistortion coefficients varying between the band limited higher order signals to provide a predistortion correction signal. The method further comprises combining the predistortion correction signal with the digital input signal to provide a predistorted digital output signal. In a preferred embodiment of the method for digitally predistorting a digital input signal deriving a plurality of band limited higher order signals from the digital input signal comprises filtering the input signal to create plural band limited signals and performing plural nonlinear operations on the band limited signals to create the band limited higher order signals. Alternatively, deriving a plurality of band limited higher order signals from the digital input signal preferably comprises performing a nonlinear operation on the input signal to create a higher order signal and performing plural filtering operations on the higher order signal to create said band limited higher order signals. The band limited higher order signals may be second order signals and the method may further comprise multiplying the band limited higher-order signals with the digital input signal to provide a third order digital signal as the predistortion correction signal. Alternatively the band limited higher order signals may be third order signals. The input signal has an associated frequency bandwidth, and one or more of the band limited higher order signals fall within the frequency bandwidth of the input signal. The predistortion coefficients preferably apply a selective weighting for the one or more higher order signals within the frequency bandwidth of the input signal. According to another aspect the present invention provides a method for digitally predistorting a digital input signal. The method comprises receiving a digital input signal and deriving a plurality of higher order signals representative of nonlinear basis functions based on a joint time frequency representation of plural samples of the digital input signal. The method further comprises weighting the plurality of higher order signals with predistortion coefficients to provide a predistortion correction signal. The method further comprises combining the predistortion correction signal with the digital input signal to provide a predistorted digital signal. In a preferred embodiment of the method for digitally predistorting a digital input signal the nonlinear basis functions comprise truncated Gaussian functions based on a Gabor expansion of the input signal. According to another aspect the present invention provides a method for adaptive digital predistortion linearization of an amplifier system. The method comprises receiving a digital input signal and deriving a plurality of band limited higher order signals from the digital input signal. The method further comprises weighting the plurality of band limited higher order signals with spectrally weighted predistortion coefficients to provide a predistortion correction signal, and combining the predistortion correction signal with the digital input signal to provide a predistorted digital signal. The method further comprises converting the predistorted digital signal from digital to analog form to provide a predistorted analog signal and up converting the predistorted analog signal to an RF signal. The method further comprises amplifying the RF signal to provide an amplified RF output signal. The method further comprises sampling the RF output signal and down converting the sampled RF output signal to a lower frequency sampled analog output signal. The method further comprises converting the lower frequency sampled analog output signal to digital form to provide a sampled digital output signal. An error signal is derived from the input digital signal and the sampled digital output signal. The method further comprises deriving spectrally weighted subsignals from the error signal and the digital input signal and adaptively generating said spectrally weighted predistortion coefficients from the spectrally weighted subsignals. Further features and advantages are described in the following detailed description of the invention.
|
20040630
|
20061212
|
20050106
|
68047.0
| 0
|
KIM, KEVIN
|
DIGITAL PREDISTORTION SYSTEM AND METHOD FOR CORRECTING MEMORY EFFECTS WITHIN AN RF POWER AMPLIFIER
|
UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,881,561
|
ACCEPTED
|
Semiconductor device and hybrid integrated circuit device
|
The related arts have difficulty in efficiently dissipating the heat generated by a resin-molded semiconductor element, and thus have the problem of thermal stress causing damage to the semiconductor element. To solve the problem, a semiconductor device of the preferred embodiments includes common leads coupled to an island, and a part of the common leads projects out from a resin seal body. The projecting common leads have a coupling portion. When mounting the semiconductor device, the common leads are bridged with brazing material. Thus, the heat generated by an integrated circuit chip mounted on the island is dissipated through the common leads to the outside of the resin seal body. In the preferred embodiments of the invention, a further improvement in heat dissipation characteristics can be accomplished by increasing the surface areas of the common leads.
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1. A semiconductor device including: an island on which a semiconductor element is mounted; a plurality of discrete leads each having an end extending near the island; a plurality of common leads coupled to the island; and a resin seal body molding the semiconductor element, the island, the discrete leads, and the common leads with resin, wherein the common leads projecting out from the resin seal body are provided with a coupling portion. 2. The semiconductor device according to claim 1, wherein when the common leads are bonded to a conductive pattern with a conductive adhesive, the common leads are bridged with the conductive adhesive between the coupling portion and the conductive portion. 3. The semiconductor device according to claim 1, wherein the common leads are coupled to both sides of the island. 4. The semiconductor device according to claim 1, wherein the common leads are each formed into a gull-wing shape. 5. A hybrid integrated circuit device including: a conductive pattern formed at least on a surface of a hybrid integrated circuit board; a semiconductor element or a passive element mounted on the conductive pattern; a lead connected to the conductive pattern and extending outside, the lead acting as an output or an input; and a resin seal body made of a thermosetting resin, which coats at least the surface of the board by transfer molding, wherein the lead has a common lead in its region projecting out from the resin seal body, and the common leads are coupled by a coupling portion. 6. The hybrid integrated circuit device according to claim 5, wherein when the common leads are bonded to a conductive pattern with a conductive adhesive, the common leads are bridged with the conductive adhesive between the coupling portion and the conductive pattern. 7. The hybrid integrated circuit device according to claim 5, wherein the common leads are each formed into a gull-wing shape. 8. The hybrid integrated circuit device according to claim 5, wherein the board is made of a metal board, and has a die-cut surface which is opposite to a surface of the board on which the conductive pattern is formed, and the die-cut surface is located on a side of a rear surface of the resin seal body.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device using a lead frame including discrete leads and common leads, and more particularly to a semiconductor device including common leads of which outer portions have a coupling portion and which are bridged with brazing material (e.g., solder or the like) in order to enhance a heat dissipation effect. 2. Description of the Related Art Recently, higher-density semiconductor devices have been sought in order to comply with smaller-sized electronic equipment. Thus, an approach has been carried out, which involves mounting on a lead frame an integrated circuit chip having various LSI (large scale integrated) circuits, and encapsulating with resin the integrated circuit chip mounted on the lead frame. The description is given with regard to a conventional semiconductor device with reference to FIGS. 8 to 10. FIG. 8 is a plan view of a conventional lead frame having an integrated circuit chip mounted thereon. FIG. 9 is a perspective view of a semiconductor device using the lead frame. FIG. 10 is a perspective view of the semiconductor device using the lead frame as mounted on a conductive pattern. As shown in FIG. 8, a lead frame 1 includes an island 3 on which an integrated circuit chip 2 is mounted, and a plurality of leads 4A, 4B, 4C, . . . , and 5A, 5B, 5C, . . . , which act as external electrode terminals. The leads 4A and the like are arranged in DIP (dual in-line package) form and spaced at predetermined intervals. The integrated circuit chip 2 is mounted on the island 3 of the lead frame 1. Electrodes 6A, 6B, 6C, . . . , and 7A, 7B, 7C, . . . placed on the integrated circuit chip 2 are respectively bonded to the leads 4A and the like through fine metal wires 8A, 8B, 8C, . . . , and 9A, 9B, 9C, . . . As shown in FIG. 9, a resin seal body 10 is formed so that the outer portions of the leads 4A and the like are exposed to the outside thereof, and thus a semiconductor device 11 is completed. As shown in FIG. 10, in the semiconductor device 11, the ends of the leads 4A and the like are brazed (e.g., soldered or otherwise bonded) to conductive patterns 14A, 14B, 14C, and the like on a printed wiring board 12. As mentioned above, the semiconductor device includes the integrated circuit chip, which is increasing in size year by year. Thus, the heat generated by the integrated circuit chip and the like can cause thermal damage to the integrated circuit chip or the semiconductor device. Although it is therefore necessary to improve heat dissipation characteristics of the semiconductor device, the semiconductor device has the problem of inadequate heat dissipation because the integrated circuit chip and the island having the chip mounted thereon are integrally molded with resin. Moreover, the lead frame having a larger number of pins becomes thinner and thus there was the problem of impairing the heat dissipation characteristics. SUMMARY OF THE INVENTION The preferred embodiments of the present invention are designed to overcome the foregoing problems. A semiconductor device of the preferred embodiments includes: an island on which a semiconductor element is mounted; a plurality of discrete leads of which ends extend near the island; a plurality of common leads coupled to the island; and a resin seal body molding the semiconductor element, the island, the discrete leads, and the common leads with resin, wherein the common leads projecting out from the resin seal body are provided with a coupling portion. With this structure, the semiconductor device can dissipate the heat through the common leads coupled to the island to the outside of the resin seal body. Therefore, heat dissipation characteristics of the semiconductor device can be improved. Moreover, a hybrid integrated circuit device of the preferred embodiments includes: a conductive pattern formed at least on a surface of a hybrid integrated circuit board; a semiconductor element or a passive element mounted on the conductive pattern; a lead connected to the conductive pattern and extending outside, the lead acting as an output or an input; and a resin seal body made of thermosetting resin, which coats at least the surface of the board by transfer molding, wherein the lead has common leads in its region projecting out from the resin seal body, and the common leads are coupled by a coupling portion. With this structure, the hybrid integrated circuit device including the transfer-molded hybrid integrated circuit board can dissipate the heat to the outside of the resin seal body. Therefore, heat dissipation characteristics of the hybrid integrated circuit device can be improved. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view explaining a lead frame for use in a semiconductor device according to a first embodiment of the present invention; FIG. 2 is a perspective view explaining the semiconductor device according to the first embodiment of the invention; FIG. 3 is a perspective view explaining the semiconductor device according to the first embodiment of the invention as mounted on a conductive pattern; FIG. 4 is an enlarged partial perspective view of the semiconductor device according to the first embodiment of the invention as mounted on the conductive pattern; FIGS. 5A and 5B are a cross-sectional view and a plan view, respectively, explaining a hybrid integrated circuit board according to a second embodiment of the invention; FIGS. 6A and 6B are a cross-sectional view and a plan view, respectively, explaining a hybrid integrated circuit device according to the second embodiment of the invention; FIG. 7 is a perspective view explaining the hybrid integrated circuit device according to the second embodiment of the invention; FIG. 8 is a plan view explaining a lead frame for use in a conventional semiconductor device; FIG. 9 is a perspective view explaining the conventional semiconductor device; and FIG. 10 is a perspective view explaining the conventional semiconductor device as mounted on a conductive pattern. DETAILED DESCRIPTION OF THE INVENTION Firstly, the description is given with reference to FIGS. 1 to 4 with regard to a semiconductor device according to a first embodiment of the present invention. FIG. 1 is a plan view explaining a lead frame for use in this embodiment. FIG. 2 is a perspective view explaining the semiconductor device according to this embodiment. FIG. 3 is a perspective view explaining the semiconductor device according to this embodiment as mounted on a conductive pattern. FIG. 4 is an enlarged partial perspective view of the semiconductor device according to this embodiment as mounted on the conductive pattern. As shown in FIG. 1, a lead frame 21 includes an island 23 on which an integrated circuit chip 22 is mounted, a plurality of discrete leads 24A, 24B, 24C, . . . , and 25A, 25B, 25C, . . . , which act as external electrode terminals, and a plurality of common leads 24M, 24N, 24P, 24Q, 25M, 25N, 25P, and 25Q, which are coupled to the island 23. The island 23 is located in the center of the lead frame 21. A plurality of discrete leads 24A and the like, and a plurality of common leads 24M and the like are arranged in DIP form and spaced at predetermined intervals on both sides of the island 23. The common leads 24M and the like have one ends coupled to the island 23, and the other ends which extend to the outside of the island 23 so as to act as outer portions. The common leads 24M and the like are arranged adjacently to one another in the center of arrays of leads located on both sides of the island 23. The discrete leads 24A and the like are arranged on both sides of arrangements of the common leads 24M and the like, and the number of discrete leads arranged on one sides of the arrangements of the common leads is the same as the number of discrete leads arranged on the other sides thereof. In this embodiment, coupling portions 30 are used to connect the outer portions of the common leads 24M and the like. Generally, tie bars 29 are used to couple the common leads 24M and the like and couple the discrete leads 24A and the like, so that the tie bars 29 prevent resin from leaking when resin molding is performed. In this embodiment, the coupling portions 30 are located at the middle positions between the tie bars 29 and the ends of the common leads 24M and the like. Since the common leads 24M and the like have one ends coupled to the island 23, the common leads have a common potential (i.e., a ground potential) as viewed in terms of electric potential. Hence, the presence of the coupling portions 30 causes no problem in using the semiconductor device. The integrated circuit chip 22 is mounted on the island 23 of the above-mentioned lead frame 21 with a conductive adhesive such as silver paste. Many electrodes 26A, 26B, 26C, . . . , and 27A, 27B, 27C, . . . placed on the integrated circuit chip 22 are bonded to the discrete leads 24A and the like through fine metal wires 28. Electrodes 26M, 26N, . . . , and 27M, 27N, . . . having a ground potential are bonded to the common leads 24M and the like through the fine metal wires 28. Then, by transfer molding, the lead frame 21, the integrated circuit chip 22, and the inner portions of the leads are molded with resin, thereby forming a resin seal body 31. After molding, the tie bars 29 are cut off so that the discrete leads 24A and the like are electrically independent. Therefore, the common leads 24M and the like are coupled by the coupling portions 30. As shown in FIG. 2, the discrete leads 24A and the like, and common leads 24M and the like which project out from both sides of the resin seal body 31, are each curved and formed into a gull-wing shape. In this case, the coupling portions 30 are located in the vertical portions of the common leads 24M and the like. As shown in FIG. 3, in a completed semiconductor device 32, the discrete leads 24A and the like, and common leads 24M and the like, which project out from the resin seal body 31, are bonded to corresponding conductive patterns 34A, 34B, 34C, . . . on a printed wiring board 33 with brazing material (e.g., solder or the like). As shown in FIG. 4, when bonding is performed, plenty of conductive adhesive, such as brazing material (e.g., solder or the like) 35, adheres to the curved portions of the common leads 24M and the like coupled by the coupling portions 30. Thus, the brazing material (e.g., solder or the like) 35 adheres to space between the common leads 24M and the like with the coupling portions 30 therebetween, so that the common leads 24M and the like are bridged with the brazing material (e.g., solder or the like) 35. This is accomplished by utilizing the surface tension of the brazing material (e.g., solder or the like) 35. The space between the common leads 24M and the like is filled with the brazing material (e.g., solder or the like) 35, so that the common leads 24M and the like function as a large lead. With this structure, the common leads 24M and the like have a large surface area and a great thickness. Thus, the heat generated by the integrated circuit chip 22 is transferred from the island 23 to the common leads 24M and the like, which are bridged with the brazing material (e.g., solder or the like) 35. Then, the generated heat is dissipated to the outside of the resin seal body 31. As a result of practical experiments, it has been shown that the structure having the coupling portions 30 for coupling the common leads 24M and the like can achieve a twofold or more improvement in a heat dissipation effect, as compared to conventional structures not having the coupling portion 30. Next, the description is given with reference to FIGS. 5A to 7 with regard to a hybrid integrated circuit device according to a second embodiment of the present invention. FIG. 5A is a cross-sectional view explaining a hybrid integrated circuit board according to this embodiment. FIG. 5B is a plan view explaining the hybrid integrated circuit board according to this embodiment. As shown in FIG. 5A, a board having excellent heat dissipation characteristics is adopted as a hybrid integrated circuit board 41, taking into account the heat generated by a semiconductor element and the like mounted on the board 41. In this embodiment, the description is given with regard to the case in which an aluminum (hereinafter referred to simply as “Al”) board 41 is used. Although the Al board is used as the board 41 in this embodiment, the board is not necessarily limited to this. For example, a printed board, a ceramic board, a metal board, or the like may be used as the board 41 to implement this embodiment. A board made of copper (Cu), iron (Fe), an iron-nickel alloy (Fe—Ni), aluminum nitride (AlN), or the like may be used as the metal board. The board 41 has an anodized surface, and the overall anodized surface is coated with insulating resin 42 having excellent insulating characteristics such as epoxy resin. A conductive path 43a made of copper foil is formed on the insulating resin 42. An active element 45 such as a power transistor, a small signal transistor, or an IC (integrated circuit), and a passive element 46 such as a chip resistor or a chip capacitor are mounted on the conductive path 43a with conductive material such as brazing material (e.g., solder or the like) 50. The active element 45 and the like may be electrically connected to the conductive path 43a with silver (Ag) paste or the like. In the case of face-up mounting of the active element 45 such as the IC, electrodes of the IC and the like are bonded to the conductive path 43a through fine metal wires 47. An outer lead 49 made of conductive material such as Cu or Fe—Ni is connected to an external connect terminal 48 placed on the outer periphery of the board 41 with the brazing material (e.g., solder or the like) 50 or the like. As shown in FIG. 5B, the conductive path 43a is formed on the board 41. Moreover, the outer leads 49 are coupled by a tie bar 44 near the board 41 so that the tie bar 44 prevents resin from leaking when resin molding is performed. A part of the outer leads 49 have a coupling portion 54 between the tie bar 44 and the ends of the outer leads 49, and are thus used as common leads 55A, 55B, 55C, and 55D. Since the common leads 55A and the like are coupled by the coupling portion 54, the common leads 55A and the like have a common potential (i.e., a ground potential) as viewed in terms of electric potential. Next, FIG. 6A is a cross-sectional view explaining the hybrid integrated circuit device according to this embodiment. FIG. 6B is a plan view explaining the hybrid integrated circuit device according to this embodiment. As shown in FIG. 6A, the overall surface of the board 41 is coated with the insulating resin 42, and thereafter a complicated circuit is formed on the insulating resin 42, and the outer lead 49 is bonded to the board 41 through the external connect terminal 48. Then, by transfer molding with thermosetting resin, a resin seal body 51 is formed. The thermosetting resin has low viscosity and also has a lower curing temperature than the melting point (e.g., 183 degrees centigrade) of the brazing material (e.g., solder or the like) 50. Thus, the inflow of the thermosetting resin while transfer molding does not cause falling-down, breaking, or bending of a fine Al wire having a diameter of about 40 μm, for example. Moreover, in this embodiment, a die-cut surface 56 of the board 41 is located on the side of a rear surface 57 of the resin seal body 51. In other words, the conductive path 43a and the like are formed on a surface 58 of the board 41 which is opposite to the die-cut surface 56 of the board 41. A curved surface 59 is formed on the die-cut surface 56 of the board 41 while die-cutting the board 41. While transfer molding, filling of resin is performed from a bottom surface of the board 41. In this case, the curved surface 59 of the board 41 is utilized for smooth filling of the resin. As shown in FIG. 6B, holes 52 are formed in an outer periphery 53 of the board 41 (see FIG. 5B), that is, a region of the board 41 on which the circuit and the like are not formed. Since the holes 52 are formed in the region belonging to both the outer periphery 53 of the board 41 and the insulating resin 42, the structure has no problem in quality and moisture resistance. Moreover, the outer periphery 53 is provided in order to ensure a distance from a circuit region when pressing each board 41 separately. After all, the outer periphery 53 is dead space, which is effectively used as a contact region for pins to fix the board 41 while transfer molding. Moreover, in this embodiment, the board having excellent thermal conductivity is used as the board 41, so that the overall board 41 can be utilized as a heat sink, which can prevent temperatures of elements mounted on the board 41 from rising by the heat. Moreover, generated heat can be dissipated to the outside of the resin seal body 51 through the board 41. Therefore, this embodiment includes the metal board 41 directly molded, so that superior heat dissipation characteristics can be achieved and thus circuit characteristics can be improved, as compared to the semiconductor device using the lead frame. Next, FIG. 7 is a perspective view explaining the hybrid integrated circuit device according to this embodiment. As shown in FIG. 7, the outer leads 49 projecting out from one side of the resin seal body 51 are each curved and formed into a gull-wing shape. In this case, the common leads 55A and the like are also formed into the gull-wing shape, and the coupling portion 54 is located in the vertical portions of the common leads 55A and the like. Then, the outer leads 49 are bonded to corresponding conductive patterns on a printed wiring board with brazing material (e.g., solder or the like), as shown in FIG. 4 of the first embodiment. As in the case of the first embodiment described above, the brazing material (e.g., solder or the like) 50 adheres to space between the common leads 55A and the like with the coupling portion 54 therebetween, so that the common leads 55A and the like are bridged with the brazing material (e.g., solder or the like) 50. This is accomplished by utilizing the surface tension of the brazing material (e.g., solder or the like) 50. The space between the common leads 55A and the like is filled with the brazing material (e.g., solder or the like) 50, so that the common leads 55A and the like function as a large lead. With this structure, the common leads 55A and the like of the outer leads 49 each have a large surface area and a great thickness. Thus, the heat generated by the active element 45 or the passive element 46 is transferred from the board 41 to the common leads 55A and the like bridged with the brazing material (e.g., solder or the like) 50. Then, the generated heat is dissipated to the outside of the resin seal body 51. Note that, in the second embodiment, the description has been given with regard to the case in which the outer leads extend from one side of the board. However, the preferred embodiment of the present invention is not limited to this case. For example, the outer leads may extend from opposite sides of the board. In this case, the above-mentioned heat dissipation characteristics also can be improved. In addition, various modifications are possible within a range not departing from the gist of the invention. The semiconductor device of the preferred embodiments includes the island having the integrated circuit chip mounted thereon, the common leads, the coupling portion, and the brazing material with which the common leads are bridged. The common leads, the coupling portion, and the brazing material enable efficient dissipation of the heat generated by the integrated circuit chip to the outside of the resin seal body. Thus, this structure can prevent the integrated circuit chip or the semiconductor device itself from being damaged by the heat. Moreover, in the semiconductor device of the preferred embodiments, is obtained the effect that the brazing material used for bridging allows an increase in the widths of the common leads, even when a larger number of pins formed from the leads are adopted, or a larger number of pins are adopted in an extremely thin metal board. Moreover, the thicknesses of the common leads can be equivalently increased, so that heat dissipation characteristics can be improved. Furthermore, in the semiconductor device of the preferred embodiments, the discrete leads and the common leads are each formed into the gull-wing shape, so that plenty of brazing material can adhere to the curved portions of the common leads. Thus, when the common leads are bonded to the conductive patterns with the brazing material, the surface tension of the brazing material can be utilized to realize the structure that facilitates bridging the common leads. In the hybrid integrated circuit device of the preferred embodiments, the top surface of the metal board is coated with the insulating resin. The conductive pattern is formed on the insulating resin surface, and the active element and the passive element are mounted on the conductive pattern. The resin seal body is formed so as to coat the pattern and the elements. The heat generated by the active element or the passive element can be dissipated through not only the metal board but also the outer leads projecting out from the resin seal body. The common leads are formed in the outer leads, thus, heat dissipation characteristics can be further improved.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a semiconductor device using a lead frame including discrete leads and common leads, and more particularly to a semiconductor device including common leads of which outer portions have a coupling portion and which are bridged with brazing material (e.g., solder or the like) in order to enhance a heat dissipation effect. 2. Description of the Related Art Recently, higher-density semiconductor devices have been sought in order to comply with smaller-sized electronic equipment. Thus, an approach has been carried out, which involves mounting on a lead frame an integrated circuit chip having various LSI (large scale integrated) circuits, and encapsulating with resin the integrated circuit chip mounted on the lead frame. The description is given with regard to a conventional semiconductor device with reference to FIGS. 8 to 10 . FIG. 8 is a plan view of a conventional lead frame having an integrated circuit chip mounted thereon. FIG. 9 is a perspective view of a semiconductor device using the lead frame. FIG. 10 is a perspective view of the semiconductor device using the lead frame as mounted on a conductive pattern. As shown in FIG. 8 , a lead frame 1 includes an island 3 on which an integrated circuit chip 2 is mounted, and a plurality of leads 4 A, 4 B, 4 C, . . . , and 5 A, 5 B, 5 C, . . . , which act as external electrode terminals. The leads 4 A and the like are arranged in DIP (dual in-line package) form and spaced at predetermined intervals. The integrated circuit chip 2 is mounted on the island 3 of the lead frame 1 . Electrodes 6 A, 6 B, 6 C, . . . , and 7 A, 7 B, 7 C, . . . placed on the integrated circuit chip 2 are respectively bonded to the leads 4 A and the like through fine metal wires 8 A, 8 B, 8 C, . . . , and 9 A, 9 B, 9 C, . . . As shown in FIG. 9 , a resin seal body 10 is formed so that the outer portions of the leads 4 A and the like are exposed to the outside thereof, and thus a semiconductor device 11 is completed. As shown in FIG. 10 , in the semiconductor device 11 , the ends of the leads 4 A and the like are brazed (e.g., soldered or otherwise bonded) to conductive patterns 14 A, 14 B, 14 C, and the like on a printed wiring board 12 . As mentioned above, the semiconductor device includes the integrated circuit chip, which is increasing in size year by year. Thus, the heat generated by the integrated circuit chip and the like can cause thermal damage to the integrated circuit chip or the semiconductor device. Although it is therefore necessary to improve heat dissipation characteristics of the semiconductor device, the semiconductor device has the problem of inadequate heat dissipation because the integrated circuit chip and the island having the chip mounted thereon are integrally molded with resin. Moreover, the lead frame having a larger number of pins becomes thinner and thus there was the problem of impairing the heat dissipation characteristics.
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<SOH> SUMMARY OF THE INVENTION <EOH>The preferred embodiments of the present invention are designed to overcome the foregoing problems. A semiconductor device of the preferred embodiments includes: an island on which a semiconductor element is mounted; a plurality of discrete leads of which ends extend near the island; a plurality of common leads coupled to the island; and a resin seal body molding the semiconductor element, the island, the discrete leads, and the common leads with resin, wherein the common leads projecting out from the resin seal body are provided with a coupling portion. With this structure, the semiconductor device can dissipate the heat through the common leads coupled to the island to the outside of the resin seal body. Therefore, heat dissipation characteristics of the semiconductor device can be improved. Moreover, a hybrid integrated circuit device of the preferred embodiments includes: a conductive pattern formed at least on a surface of a hybrid integrated circuit board; a semiconductor element or a passive element mounted on the conductive pattern; a lead connected to the conductive pattern and extending outside, the lead acting as an output or an input; and a resin seal body made of thermosetting resin, which coats at least the surface of the board by transfer molding, wherein the lead has common leads in its region projecting out from the resin seal body, and the common leads are coupled by a coupling portion. With this structure, the hybrid integrated circuit device including the transfer-molded hybrid integrated circuit board can dissipate the heat to the outside of the resin seal body. Therefore, heat dissipation characteristics of the hybrid integrated circuit device can be improved.
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20040630
|
20060905
|
20051027
|
88298.0
| 2
|
CLARK, JASMINE JHIHAN B
|
SEMICONDUCTOR DEVICE AND HYBRID INTEGRATED CIRCUIT DEVICE
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UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,881,819
|
ACCEPTED
|
Selective input system based on tracking of motion parameters of an input device
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A selective input system and associated method is provided which tracks the motion of a pointing device over a region or area. The pointing device can be a touchpad, a mouse, a pen, or any device capable of providing two or three-dimensional location. The region or area is preferably augmented with a printed or actual keyboard/pad. Alternatively, a representation of the location of the pointing device over a virtual keyboard/pad can be dynamically shown on an associated display. The system identifies selections of items or characters by detecting parameters of motion of the pointing device, such as length of motion, a change in direction, a change in velocity, and or a lack of motion at locations that correspond to features on the keyboard/pad. The input system is preferably coupled to a text disambiguation system such as a T9® or Sloppytype™ system, to improve the accuracy and usability of the input system.
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1. A process for selectable input based on motion of a pointing device in relation to a region, the process comprising the steps of: tracking the motion of the pointing device in relation to the region; determine a device path of the pointing device, comprising a plurality of positions and corresponding times, based upon the tracked motion; for subsequent positions and corresponding times, compare to path data; detecting subsequent positions which meet at least one threshold of a selected position within the region; and entering each of the selected positions which correspond to a selection. 2. The process of claim 1, wherein the pointing device comprises any of a stylus, a finger, a hand, a glove, a pen, a mouse, a touchpad, a trackball, a laser pointer, and a light pen. 3. The process of claim 1, wherein the region comprises any of a keypad, a touchscreen, and a touchpad. 4. The process of claim 1, wherein the threshold of a selected position within the region comprises any of starting the device path, looping the device path, changing direction of the device path, changing velocity of the device path, pausing motion in the device path, and ending the device path. 5. The process of claim 4, wherein the threshold of changing direction comprises any of a curve having an estimated radius that is less than a threshold geometry, a comparison of the device path direction before and after a curve, a sharp cusp edge in the device path, and a comparison of path direction before and after a cusp. 6. The process of claim 1, wherein the region comprises a two-dimensional area. 7. The process of claim 6, wherein the region further comprises a secondary input value. 8. The process of claim 7, wherein the secondary input value comprises a stylus pressure value. 9. The process of claim 1, wherein the region comprises a three-dimensional volume. 10. The process of claim 1, wherein the tracked motion is limited to motion of the pointing device on a planar surface of the region. 11. The process of claim 1, wherein the tracked motion of the pointing device comprises any of planar motion and non-planar motion of the pointing device in relation to a surface of the region. 12. The process of claim 1, wherein the region comprises an input region in any of a portable digital assistant, a portable telephone, a mobile telephone, a portable computer, and a portable game device. 13. The process of claim 1, further comprising the step of: disambiguating at least one determined position which corresponds to an alternate selection. 14. The process of claim 13, wherein the step of disambiguation comprises the steps of: displaying the alternate selection; and providing a choice by the user between the determined position and the alternate selection. 15. The process of claim 1, further comprising the step of: disambiguating at least one subsequent position based upon a contextual comparison between the subsequent position and stored information. 16. The process of claim 15, wherein the stored information comprises any of language, characters, and words. 17. The process of claim 15, wherein the step of disambiguation comprises the steps of: providing a spell check function for one or more selected positions; and providing a choice by the user of results of the spell check function. 18. The process of claim 1, further comprising the step of: disambiguating at least one subsequent position which does not clearly indicate a selected position within the region. 19. The process of claim 18, wherein the step of disambiguating comprises the steps of: displaying at least one selectable position which may correspond to the subsequent position that does not clearly indicate a selected position within the region; and providing a choice by the user of the at least one selectable position. 20. The process of claim 1, further comprising the step of: providing feedback to a user. 21. The process of claim 20, wherein the feedback comprises any of visual feedback and audio feedback. 22. The process of claim 21, wherein the visual feedback comprises any of an ink trail corresponding to the determined device path, a font change, a color change, a reverse video color, an alternate background color, an underline, bold face text, italic text, and a text outline, 23. The process of claim 21, wherein the audio feedback comprises any of a tone indicating system confidence in any of tracking and selection, a sound indicating any of a selection and an entry, and an acoustic message. 24. The process of claim 1, further comprising the steps of: determining a distance between a current location of the pointing device and selectable positions within the region; determining a selectable position which is closest to the current location of the pointing device; and highlighting the determined closest selectable position. 25. The process of claim 24, wherein the highlighting comprises any of a display and a magnification of the determined closest selectable position. 26. The process of claim 1, wherein the selected positions correspond to any of characters, menu selections, and functions. 27. The process of claim 1, further comprising the step of: providing a plurality of interfaces comprising a plurality of selected position within the region; and switching between the interfaces. 28. The process of claim 27, wherein the step of switching between the interfaces comprises a selection by the pointing device. 29. The process of claim 27, wherein the step of switching between the interfaces comprises a selection by a supplementary control. 30. The process of claim 1, further comprising the steps of: predicting a default selection; and providing means for accepting the predicted default selection. 31. The process of claim 30, wherein the predicted default selection comprises a word. 32. The process of claim 30, wherein the accepting means comprises any of a directional input, a button selection, a menu selection, a list selection, and a functional input. 33. A process for selectable input based on motion of a pointing device in relation to a region, the process comprising the steps of: tracking the motion of the pointing device in relation to the region; detecting a characteristic motion of the pointing device, the characteristic motion corresponding to at least one selectable input. 34. The process of claim 33, wherein the pointing device comprises any of a stylus, a finger, a hand, a glove, a pen, a mouse, a touchpad, a trackball, a laser pointer, and a light pen. 35. The process of claim 33, wherein the region comprises any of a keypad, a touchpad, and an entry screen. 36. The process of claim 33, wherein the characteristic motion comprises any of starting the device path, looping the device path, changing direction of the device path, changing velocity of the device path, pausing motion in the device path, and ending the device path. 37. The process of claim 36, wherein the characteristic motion of changing direction comprises any of a curve having an estimated radius that is less than a threshold geometry, a comparison of the device path direction before and after a curve, a sharp cusp edge in the device path, and a comparison of path direction before and after a cusp. 38. The process of claim 33, wherein the region comprises a two-dimensional area. 39. The process of claim 38, wherein the region further comprises a secondary input value. 40. The process of claim 39, wherein the secondary input value comprises a stylus pressure value. 41. The process of claim 33, wherein the region comprises a three-dimensional volume. 42. The process of claim 33, wherein the tracked motion is limited to motion of the pointing device on a planar surface of the region. 43. The process of claim 33, wherein the tracked motion of the pointing device comprises any of planar motion and non-planar motion of the pointing device in relation to a surface of the region. 44. The process of claim 33, wherein the region comprises an input area in any of a portable digital assistant, a portable telephone, a mobile telephone, a portable computer, and a portable game device. 45. The process of claim 33, further comprising the step of: disambiguating at least one determined position which corresponds to an alternate selection. 46. The process of claim 45, wherein the step of disambiguation comprises the steps of: displaying the alternate selection; and providing a choice by the user between the determined position and the alternate selection. 47. The process of claim 33, further comprising the step of: providing feedback to a user. 48. The process of claim 47, wherein the feedback comprises any of visual feedback and audio feedback. 49. The process of claim 48, wherein the visual feedback comprises any of an ink trail corresponding to the determined device path, a font change, a color change, a reverse video color, an alternate background color, an underline, bold face text, italic text, and a text outline. 50. The process of claim 48, wherein the audio feedback comprises any of a tone indicating system confidence in any of tracking and selection, a sound indicating any of a selection and an entry, and an acoustic message. 51. The process of claim 33, further comprising the steps of: determining a distance between a current location of the pointing device and selectable positions within the region; determining a selectable position which is closest to the current location of the pointing device; and highlighting the determined closest selectable position. 52. The process of claim 51, wherein the highlighting comprises any of a display and a magnification of the determined closest selectable position. 53. The process of claim 33, further comprising the step of: disambiguating at least one subsequent position based upon a contextual comparison between the subsequent position and stored information. 54. The process of claim 53, wherein the stored information comprises any of language, characters, and words. 55. The process of claim 53, wherein the step of disambiguation comprises the steps of: providing a spell check function for one or more selected positions; and providing a choice by the user of results of the spell check function. 56. The process of claim 33, further comprising the step of: disambiguating at least one subsequent position which does not clearly indicate a selected position within the region. 57. The process of claim 56, wherein the disambiguating step comprises the steps of: displaying at least one selectable position which may correspond to the subsequent position that does not clearly indicate a selected position within the region; and providing a choice by the user of the at least one selectable position. 58. The process of claim 33, wherein the selected positions correspond to any of characters, menu selections, and functions. 59. The process of claim 33, further comprising the step of: providing a plurality of interfaces comprising a plurality of selected position within the region; and switching between the interfaces. 60. The process of claim 59, wherein the step of switching between the interfaces comprises a selection by the input device. 61. The process of claim 59, wherein the step of switching between the interfaces comprises a selection by a supplementary control. 62. The process of claim 33, further comprising the steps of: predicting a default selection; and providing means for accepting the predicted default selection. 63. The process of claim 62, wherein the predicted default selection comprises a word. 64. The process of claim 62, wherein the accepting means comprises any of a directional input, a button selection, a menu selection, a list selection, and a functional input. 65. A system for selectable input based on motion of a pointing device in relation to an region, comprising: means for tracking the motion of the pointing device in relation to the region; a determined device path, comprising a plurality of positions and corresponding times, based upon the tracked motion; a comparison of subsequent positions and corresponding times to path data; means for detecting subsequent positions which meet at least one threshold of a selected position within the region; and means for sequential entry of each of the selected positions which correspond to a selection. 66. The system of claim 65, wherein the pointing device comprises any of a stylus, a finger, a hand, a glove, a pen, a mouse, a touchpad, a trackball, a laser pointer, and a light pen. 67. The system of claim 65, wherein the region comprises any of a keypad, a touchpad, and an entry screen. 68. The system of claim 65, wherein the threshold of a selected position within the region comprises any of starting the device path, looping the device path, changing direction of the device path, changing velocity of the device path, pausing motion in the device path, and ending the device path. 69. The system of claim 68, wherein the threshold of changing direction comprises any of a curve having an estimated radius that is less than a threshold geometry, a comparison of the device path direction before and after a curve, a sharp cusp edge in the device path, and a comparison of path direction before and after a cusp. 70. The system of claim 65, wherein the region comprises a two-dimensional area. 71. The system of claim 70, wherein the region further comprises a secondary input value. 72. The system of claim 71, wherein the secondary input value comprises a stylus pressure value. 73. The system of claim 65, wherein the region comprises a three-dimensional volume. 74. The system of claim 65, wherein the tracked motion is limited to motion of the pointing device on a planar surface of the region. 75. The system of claim 65, wherein the tracked motion of the pointing device comprises any of planar motion and non-planar motion of the device in relation to a surface of the region. 76. The system of claim 65, wherein the region comprises an input area in any of a portable digital assistant, a portable telephone, a mobile telephone, a portable computer, and a portable game device. 77. The system of claim 65, further comprising: means for disambiguating at least one determined position which corresponds to an alternate selection. 78. The system of claim 77, wherein the disambiguation means comprises: a display of the alternate selection; and a selectable choice by the user between the determined position and the alternate selection. 79. The system of claim 65, further comprising: means for providing feedback to a user. 80. The system of claim 79, wherein the feedback comprises any of visual feedback and audio feedback. 81. The system of claim 80, wherein the visual feedback comprises any of an ink trail corresponding to the determined device path, a font change, a color change, a reverse video color, an alternate background color, an underline, bold face text, italic text, and a text outline, 82. The system of claim 80, wherein the audio feedback comprises any of a tone indicating system confidence in any of tracking and selection, a sound indicating any of a selection and an entry, and an acoustic message. 83. The system of claim 65, further comprising: Logic for determining a distance between a current location of the pointing device and selectable positions within the region; logic for determining a selectable position which is closest to the current location of the pointing device; and a highlight corresponding to the determined closest selectable position. 84. The system of claim 83, wherein the highlight comprises any of a display and a magnification of the determined closest selectable position. 85. The system of claim 65, further comprising: means for disambiguating at least one subsequent position based upon a contextual comparison between the subsequent position and stored information. 86. The system of claim 85, wherein the stored information comprises any of language, characters, and words. 87. The system of claim 85, wherein the disambiguation means comprises: a spell check function for one or more selected positions; and a choice for the user of results of the spell check function. 88. The system of claim 65, further comprising: a disambiguation of at least one subsequent position which does not clearly indicate a selected position within the region. 89. The system of claim 88, wherein the disambiguation comprises: a display of at least one selectable position which may correspond to the subsequent position that does not clearly indicate a selected position within the region; and a selectable choice for the user of the at least one selectable position. 90. The system of claim 65, wherein the selected positions correspond to any of characters, menu selections, and functions. 91. The system of claim 65, further comprising: a plurality of interfaces comprising a plurality of selected position within the region; and means for switching between the interfaces. 92. The system of claim 91, wherein the means for switching between the interfaces comprises a pointing device selection. 93. The system of claim 91, wherein the means for switching between the interfaces comprises a supplementary control. 94. The system of claim 65, further comprising: logic for predicting a default selection; and means for accepting the predicted default selection. 95. The system of claim 94, wherein the predicted default selection comprises a word. 96. The system of claim 94, wherein the accepting means comprises any of a directional input, a button selection, a menu selection, a list selection, and a functional input. 97. A system for selectable input based upon motion of a pointing device in relation to an region, comprising: means for tracking the motion of the pointing device in relation to the region; logic for determining a characteristic motion of the pointing device which corresponds to at least one selectable input. 98. The system of claim 97, wherein the pointing device comprises any of a stylus, a finger, a hand, a glove, a pen, a mouse, a touchpad, a trackball, a laser pointer, and a light pen. 99. The system of claim 97, wherein the region comprises any of a keypad, a touchpad, and an entry screen. 100. The system of claim 97, wherein the characteristic motion comprises any of starting the device path, looping the device path, changing direction of the device path, changing velocity of the device path, pausing motion in the device path, and ending the device path. 101. The system of claim 97, wherein the characteristic motion of changing direction comprises any of a curve having an estimated radius that is less than a threshold geometry, a comparison of the device path direction before and after a curve, a sharp cusp edge in the device path, and a comparison of path direction before and after a cusp. 102. The system of claim 97, wherein the region comprises a two-dimensional area. 103. The system of claim 102, wherein the region further comprises a secondary input value. 104. The system of claim 103, wherein the secondary input value comprises a stylus pressure value. 105. The system of claim 97, wherein the region comprises a three-dimensional volume. 106. The system of claim 97, wherein the tracked motion is limited to motion of the pointing device on a planar surface of the region. 107. The system of claim 97, wherein the tracked motion of the pointing device comprises any of planar motion and non-planar motion of the device in relation to a surface of the region. 108. The system of claim 97, wherein the region comprises an input area in any of a portable digital assistant, a portable telephone, a mobile telephone, a portable computer, and a portable game device. 109. The system of claim 97, further comprising: means for disambiguating at least one determined position which corresponds to an alternate selection. 110. The system of claim 109, wherein the disambiguation means comprises: a display of the alternate selection; and a selectable choice by the user between the determined position and the alternate selection. 111. The system of claim 97, further comprising: means for providing feedback to a user. 112. The system of claim 111, wherein the feedback comprises any of visual feedback and audio feedback. 113. The system of claim 112, wherein the visual feedback comprises any of an ink trail corresponding to the tracked motion, a font change, a color change, a reverse video color, an alternate background color, an underline, bold face text, italic text, and a text outline, 114. The system of claim 112, wherein the audio feedback comprises any of a tone indicating system confidence in any of tracking and selection, a sound indicating any of a selection and an entry, and an acoustic message. 115. The system of claim 97, further comprising: logic for determining a distance between a current location of the pointing device and selectable positions within the region; logic for determining a selectable position which is closest to the current location of the pointing device; and a highlight corresponding to the determined closest selectable position. 116. The system of claim 115, wherein the highlight comprises any of a display and a magnification of the determined closest selectable position. 117. The system of claim 97, further comprising: means for disambiguating at least one subsequent position based upon a contextual comparison between the subsequent position and stored information. 118. The system of claim 117, wherein the stored information comprises any of languages, characters, and words. 119. The system of claim 117, wherein the disambiguation means comprises: a spell check function for one or more selected positions; and a choice for the user of results of the spell check function. 120. The system of claim 97, further comprising: a disambiguation of at least one subsequent position which does not clearly indicate a selected position within the region. 121. The system of claim 120, wherein the disambiguating comprises: a display of at least one selectable position which may correspond to the subsequent position that does not clearly indicate a selected position within the region; and a selectable choice for the user of the at least one selectable position. 122. The system of claim 97, wherein the selected positions correspond to any of characters, menu selections, and functions. 123. The system of claim 97, further comprising: a plurality of interfaces comprising a plurality of selected position within the region; and means for switching between the interfaces. 124. The system of claim 97, wherein the means for switching between the interfaces comprises a pointing device selection. 125. The system of claim 97, wherein the means for switching between the interfaces comprises a supplementary control. 126. The system of claim 97, further comprising: logic for predicting a default selection; and means for accepting the predicted default selection. 127. The system of claim 126, wherein the predicted default selection comprises a word. 128. The system of claim 126, wherein the accepting means comprises any of a directional input, a button selection, a menu selection, a list selection, and a functional input.
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CROSS REFERENCE TO RELATED APPLICATIONS This Application also claims priority for U.S. Provisional Patent Application Ser. No. 60/504,552, entitled SELECTIVE INPUT SYSTEM BASED ON TRACKING OF MOTION PARAMETERS OF AN INPUT DEVICE, US Filing Date 19 Sep. 2003. This Application is a Continuation In Part of U.S. patent application Ser. No. 10/677,890 (TEGI0013), entitled DIRECTIONAL INPUT SYSTEM WITH AUTOMATIC CORRECTION, US Filing Date 01 Oct. 2003, which claims priority to U.S. patent application Ser. No. 10/205,950, filed 25 Jul. 2002; to U.S. patent application Ser. No. 09/580,319 filed 26 May 2000, entitled KEYBOARD SYSTEM WITH AUTOMATIC CORRECTION; and to U.S. Provisional Patent Application Ser. No. 60/461,735, filed 09 Apr. 2003. FIELD OF THE INVENTION The invention relates to input devices and user interfaces. More particularly, the invention relates to the tracking of the position and/or motion of an input device and selection of items or character input based on the tracking. BACKGROUND OF THE INVENTION Input devices often comprise means for pointing or selecting, such as by a stylus, finger, or mouse, whereby a user may interact with a device. The user is often required to interact with a user interface, such as a keypad, touchpad, or touch screen, such as to input a desired character. A user typically maneuvers the pointing or selection device over a desired position over the interface, and then taps or sets the pointing device, to activate a chosen region or element, e.g. such as an actual or mapped keypad element or character. A user is often required to perform a large number of selective pointing actions, which can be difficult to perform, and are prone to error. Furthermore, the user interfaces for many devices are often small, such as for small electronic devices, e.g. portable cell phones, personal digital assistants (PDAs), or other devices often used for business, personal, educational, or recreational purposes. The selective pointing functions required to operate such small devices have become increasingly difficult and prone to error, as a user must accurately tap on a very small region within a user interface. Several structures and methods have been described, to facilitate the entry of information within stylus-based devices. For example, in a Palm personal digital assistant (PDA), available through Palm Inc., of Milpitas, Calif., a handwriting recognition system, such as Graffiti®, is provided, wherein a user, preferably with a stylus, enters shorthand-style simplified patterns within a designated entry region of an input screen. Entered motions are analyzed to determine the entered characters, which are then placed within an “active” or cursor region for the device. For example, for a cursor location corresponding to time, e.g. 2:30PM, within a schedule application, a user may enter “Meet with Fred”. Shumin Zhai and Per-Ola Kristensson, Shorthand Writing on Stylus Keyboard, Apr. 5-10, 2003, describe a method for computer-based writing, wherein a shorthand symbol is provided and taught for each word, according to a pattern on a stylus keyboard. A gesture pattern is typically made by tapping the first letter of a word, and gliding the stylus over to subsequent characters in a word. A word is recognized by the pattern of the gesture over the keyboard. Jennifer Mankoff and Gregory D. Abowd, Error Correction Techniques, submitted to Interact '99, provides a survey of the “design, implementation, and study of interfaces for correcting error prone input technologies”. Jennifer Mankoff and Gregory D. Abowd, Cirrin: A Word-Level Unistroke Keyboard for Pen Input, Proceedings of UIST 1998, Technical note. pp.213-214, describe a structure and method for planar entry of words, with a non-planar motion typically used between words. Keyboard designs are described, in which letters are arranged about the periphery of a neutral area. Each word is begun by starting a stylus path within a central, ie. neutral region. A user is then required to trace out a path which crosses, i.e. travels through, selected letters, while entering the central, neutral region as necessary, between successive letters. K. Perlin, Quikwriting: Continuous Stylus-Based Text Entry; presented at A C M UIST'98 Conference, describes a shorthand for entering text, wherein the x,y positions of a stylus on a surface are tracked. The surface includes nine zones, including a central resting zone. A token is created whenever the stylus enters or exits any of the zones, and the sequence of tokens is used to determine the entered characters. The system typically requires that the stylus begin each word from a central resting zone. The system also often requires movement between two zones for the determined selection of most characters, while for characters which are defined to be “frequent”, the movement from a central resting zone to an outer zone and back to the resting zone can be used. M. Garrett, D. Ward, I. Murray, P. Cowans, and D. Mackay, Implementation of Dasher, an Information Efficient Input Mechanism, presented at LINUX 2003 Conference, Edinburgh, Scotland, describe a text entry system which uses “a language model to offer predictions to the user without constraining the range of words which can be written”, such as for “providing input on keyboardless devices and for disabled users”. The input system presents letters which move across a screen, wherein a user navigates a cursor into the zones for each letter. Zones for common letters, based on letters and words already presented, are bigger. Other work describing text input technologies is provided by P. Isokoski and R. Raisamo, Device Independent Text Input: A Rationale and an Example, Proceedings of the Working Conference on Advanced Visual Interfaces AVI2000, pages 76-83, Palermo, Italy, 2000; P. Isokoski, Text Input Methods for Eye Trackers Using Off-Screen Targets, In Proceedings of Eye Tracking Research & Applications Symposium 2000, pages 15-22. ACM, 2000; P. Isokoski, Model for Unistroke Writing Time, CHI Letters: Human Factors in Computing Systems, CHI 2001, 3(1):357-364, 2001; P. Isokoski and M. Käki. Comparison of Two Touchpad-Based Methods for Numeric Entry, CHI Letters: Human Factors in Computing Systems, CHI 2002, 4(1): 25-32, 2002; P. Isokoski and I. Scott MacKenzie, Text Entry on Mobile Systems: Directions for the Future, CHI 2001 Extended Abstracts, page 495, 2001; P. Isokoski and I. S. MacKenzie; Report on the CHI2001 Workshop on Text Entry on Mobile Systems, SIGCHI Bulletin, p. 14, September/October 2001; P. Isokoski and I. S. MacKenzie. Combined Model for Text Entry Rate Development, CHI2003 Extended Abstracts, pp. 752-753, 2003; P. Isokoski and R. Raisamo, Architecture for Personal Text Entry Methods, In Closing the Gaps: Software Engineering and Human-Computer Interaction, pp. 1-8. IFIP, 2003. While such entry systems provide a means for entering information, the required shorthand or stylus paths are often complex, and movements required for one character are easily mistaken for different characters. A user is therefore often required to retype one or more characters, if the mistakes are even noticed. It would be advantageous to provide an input system that makes selection or character input based on determined motions of input device over an area, i.e. the individual characteristic motions which, as a whole, make up a pattern. The development of such a user input system would constitute a major technological advance. It would also be advantageous to provide a user input system, wherein selections of items or characters are determined, i.e. distinguished, by detecting parameters of motion of an input device, such as length of motion, a change in direction, a change in velocity, and/or a pause in motion, at locations that correspond to features on the keyboard/pad. The development of such a user input system would constitute a major technological advance. As well, it would be advantageous to provide an input system which makes selection or character input based on the motion of input device over an area, which is coupled to a text disambiguation system such as T9® or SloppyType™ system, to improve the accuracy and usability of the input system. The development of such a user input system would constitute a further major technological advance. SUMMARY OF THE INVENTION A selective input system and associated method are provided, which track the motion of an input device over an area. The input device can be a touchpad, a mouse, a pen, or any device capable of providing a location, e.g. such as an x-y location and/or a location based on alternate or additional dimensions. The area is preferably augmented with a printed or actual keyboard/pad. Alternatively, a representation of the location of the input device over a virtual keyboard/pad can be dynamically shown on an associated display. The system identifies selections of items or characters by detecting parameters of motion of the input device, such as length of motion, a change in direction, a change in velocity, and or a lack of motion at locations that correspond to features on the keyboard/pad. The input system is preferably coupled to a text disambiguation system, such as a T9® or SloppyType™ system, to improve the accuracy and usability of the input system. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a character input system, in which discrete positions of an input device within an input area are determined; FIG. 2 is a detailed schematic view of a character input system based on exemplary movement and time-based tracking of an input device; FIG. 3 is a schematic view of a touch screen, wherein stylus input and char/key display preferably share a common interface; FIG. 4 is a schematic view of an alternate device structure, comprising one or more unprinted inputs linked to a separate display; FIG. 5 is a schematic view of a printed entry pad and an output and/or editor display; FIG. 6 is a schematic view of a selective input system comprising a circular onscreen input area; FIG. 7 is a schematic view of a character input system based on the tracking of absolute positions of an input device; FIG. 8 is a flowchart of an exemplary process for device tracking and character input based on the tracking; FIG. 9 is a schematic block diagram of a directional input system 160 incorporating disambiguation and associated external information; FIG. 10 is a schematic view of preferred processing, input, and display systems associated with an input system based on the tracking of absolute positions of an input device; FIG. 11 is a schematic view of an alternate selective input system based on the tracking of motion and/or position of a pointing device, wherein functions of an input region are changeable based on stylus input and/or device controls; FIG. 12 is a schematic view of an alternate selective input system based on the tracking of motion and/or position of a pointing device, wherein the input area is changeable for function and/or appearance; and FIG. 13 is a perspective view of an alternate selective input system based on the tracking of motion of an input device through a region or volume. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a user input system 10, in which discrete positions of a pointing device, i.e. instrument 16 within an input area 14 are determined. Devices 12 often comprise means 16 for pointing or selecting, such as by a stylus, finger, or mouse, whereby a user may interact with a device 12. The user is often required to interact with a user interface area 14, such as a keypad, touchpad, or touch screen, such as to input a desired character 20. In the user input system 10 shown in FIG. 1, a user typically maneuvers the pointing or selection device 16 over a desired position 24, e.g. 24a, over the interface area 14, and then taps or sets 19 the pointing device 16, such as by contacting a pointing tip or pointer 17 to a desired location 24 within an interface area 14, to activate a chosen region or element, e.g. such as an actual or mapped keypad element or character 20. As described above, a user is often required to perform a large number of selective pointing actions 19, which can be difficult to perform, and are prone to error. Furthermore, the user interfaces 14 for many devices 12 are often small, such as for small electronic devices, e.g. portable cell phones, personal digital assistants (PDAs), or other devices often used for business, personal, educational, or recreational purposes. The selective pointing functions 19 required to operate such small devices have become increasingly difficult and prone to error, as a user must accurately tap 19 on very small regions within a user interface. FIG. 2 is a detailed schematic view 32 of a selective input system 30 based on exemplary movement paths 38 and time-based tracking 34, e.g. 34a-34n, of a pointing device 16, such as within an input region 14, such as an area or volume 14. The system 30 and associated process 98 (FIG. 8) identifies character selections, by detecting path starts 42, directional changes 46, velocity changes, e.g. motion pauses 48, and/or path ends 50, at or determined to be near to locations that correspond to features within the input region 14. As seen in FIG. 2, a path 38 of a device 16 may indicate selected positions 34 by one or more techniques, such as by the start 42 of a path 38, a determined loop 44 in the path 38, a direction change 46, a velocity change, e.g. slowing down or pausing in a location 34, an acceleration away from a location 34, or the end 50 of a path 38. One or more of selected position techniques may be implemented within a selective input system 30, and may also be integrated with the use of pointing or tapping 19 (FIG. 1), such that a device 12 may be easily and intuitively operated by a user. For example, causing the pointing device 16 to hover over a character 20 for a certain amount of time 36 can be interpreted as a selection of the character 20. Moving the pointing device 16 towards and away from a character 20, such as to and from and from a character 20, i.e. changing direction 46, can be interpreted as a selection 20. Circling 44 a character can be interpreted as a selection. A slowing down or pausing 48 motion over a character 20 can also be interpreted as selection of a character 20. While the exemplary selective input system 30 shown in FIG. 2 is based on two-dimensional movement 38 and time-based tracking 34, e.g. 34a-34n, of a pointing device 16, within an area 14, alternate system embodiments of the selective input system 30 provide three-dimensional tracking, such as in relation to an X-axis 18a, a Y-axis 18b, and a Z-axis 18c, or in relation to other coordinate systems 92, e.g. 92a-92c (FIG. 6). While the change in direction 46 in FIG. 2 is shown to occur within a small area, comprising a small radius of curvature 47, a change of direction may alternately be determined by other path geometries or characteristics, e.g. such as but not limited to a change in direction over a curve having an estimated radius that is less than a threshold geometry, a sharp cusp edge in a path, or a comparison of path direction before and after a curve or cusp, e.g. such as a change in direction greater than a threshold angle may be used to signify a selection location 34. In some system embodiments, circling the same selectable region or character 20 multiple times can be interpreted as selecting the character multiple times. Similarly, movement back and forth over a selectable region or character 20 can be interpreted as selecting the same character 20 multiple times. The selective input system 30 may be implemented on a wide variety of devices 12, such as but not limited to personal computers, mobile devices, appliances, controls, and other microprocessor-based devices, such as portable digital assistants, network enabled cell phones, or other devices often used for business, industrial, personal, educational, or recreational purposes. FIG. 3 is a schematic view 60 of a touchscreen device 12a, such as a personal digital assistant (PDA) or a tablet personal computer (PC), where the stylus input and char/key display are effectively the same. A combined region 62 typically comprises a stroke input region 14a, as well as a display region 64, such as to display characters, words, or keys. The combined region 62 may also preferably provide a message display region 66. The device may also comprise supplementary controls 68, such as for navigation within or between device functions. FIG. 4 is a schematic view 70 of an alternate device structure 12b, comprising an unprinted input 14b, e.g. such as a trackpad 72a, a tablet 72b, and/or a joystick 72k, linked, such as through a processor 73, to a separate display 76. Selectable movement-38, e.g. 38a-38k, through the input device 14b, e.g. 72a-72c, is tracked, and the path 38 in the input device 14b is indicated in a corresponding displayed path 78, e.g. such as through one or more determined paths 78, i.e. ink trails 78, and/or mouse/crosshair cursors 79. Detected movement paths 38, in relation to the input device 14b, are typically indicated within a char/key area 75, such as in relation to selectable characters, words, items, or keys 20a-20n. As seen in FIG. 4, an optional ink trail 78 provides a means for visual feedback for hardware configurations 12 in which a char/key area 75 (FIG. 4) is displayed on a screen. In some preferred embodiments, the appearance of the displayed ink trail 78 can change, e.g. color or thickness, to indicate that a selection region has been registered, and/or to indicate a level of system confidence that motion in a region was properly interpreted as a selection. The ink trail 78 can additionally be enhanced, such as by a highlight, an illumination, a sparkle, or a blinking selection 20, to indicate one or more interpreted selections. In some preferred systems 30b, an ink trail 78 comprises an alternate or complementary audio highlight 81a through an audio output circuit 77. For example, the audio highlight 81a can provide audio feedback to a user USR, such as a tone that rises and falls or fades, wherein the pitch or timbre may preferably indicate system confidence in tracking 34 or a selection 20. Audio highlighting 81a is often preferable for spatial, i.e. 3-dimensional, system embodiments 30g (FIG. 13). In some system embodiments of the selective input system 30, such as in the selective input system 30b shown in FIG. 4, an auxiliary visual feedback 81b may preferably be provided, such as to display and/or magnify a selectable position 20, such as a selectable area or letter 20, which is determined to be closest to the current tracked location 34. For example, in systems 30 which comprise a printed trackpad 72a or touch screen 72b, where a finger is the primary pointing device 16, and/or in low-light situations, the nearest letter 20 or the immediate selectable area surrounding the current location 34 being tracked may be displayed or magnified 81b, such as in or over the display 74. The visual highlight 81b provides a user USR a visual indication 73 of where the pointing device 16 is currently located 34, i.e. making contact, such as to increase selection accuracy for a pointing device 16, for example when a finger of a user USR blocks a portion of the keyboard area from view, or for lighting conditions which disable viewing. FIG. 5 is a schematic view 80a of a device 12c comprising a printed input area 14c, such as a trackpad and/or labeled phone keypad, which provides a permanent character/key area. The input area 14c is linked to a text output display window 182a, for the display of word choice lists, and/or for a text editing display. FIG. 6 is a schematic view 80b of a device 12d comprising an exemplary non-rectangular, e.g. circular, onscreen input area 14d, corresponding to a selective input system 30. The screen includes an on-screen keyboard 14d and a text display area 62. In alternate system embodiments, the selectable characters 20 may be printed around the joystick device 72k. The on-screen keyboard area 14d can take a variety of shapes, including but not limited to circle, square, oval and polygon with any number of sides. The visual representation is typically, but not limited to, a two-dimensional plane figure. The on-screen keyboard 14d may be enhanced by, or even replaced with, a set of compass point letters, such as ‘A’, ‘H’, ‘N’ and ‘U’. These compass pointer letters can also be placed in an interactive pointer/cursor on screen or even around the input device 14b, such as around a joystick device 72k. The letters in the on-screen keyboard 14d can be arranged in any order or orientation. In the preferred layout as shown in FIG. 6, all letters 20 have their bottoms towards the center of the first ring 83a. In an alternative layout, all letters 20 may be upright. In the preferred layout as shown in FIG. 6, the letters are ordered alphabetically. In an alternative layout, the letters may follow the Dvorak order. In the preferred layout as shown in FIG. 6, the letters start at the 12 o'clock position. In an alternative layout, the letters may start at the 9 o'clock location. Alternatively, the letters may have a moving starting position in a rotating keyboard in an embodiment, for example, where the input device is a type of wheel. In the preferred layout as shown in FIG. 6, the letters are placed clockwise in a first character ring 83a. In an alternate layout, the letters may be placed counterclockwise. In the preferred embodiment as shown in FIG. 6, letters 20 occupy different amount of radians depending upon their frequency of use in the language, giving more frequent letters a larger target area. In some system embodiments the sizing of letters 20 can also be dynamic, with letters 20 more likely to follow the just registered letter given more area. Similarly, selectable digits 20, i.e. “0” through “9”, can be arranged in any order or orientation. For example, selectable digits 20 can be located adjacent to the series of letters 20 assigned to the corresponding digit keys on a telephone keypad. The on-screen keyboard 14d may include letters of a primary input language, letters of alternate input languages (and/or accented letters), digits, and punctuation symbols. The keyboard may also include character components for pictographic languages, diacritics and other “zero-width” characters that attach to preceding characters. The keyboard may further include tone marks, bidirectional characters, functions indicated by a word or symbol, and symbolic representation of a set of characters such as “Smart Punctuation”. The preferred primary text input keyboard as shown in FIG. 6 includes unaccented is letters which form an outer ring 83a, digits which form an inner ring 83b, and a symbol or an indicator 85 between the letters “z” and “a”, called “Smart Punctuation”, which intuitively determines which punctuation is most appropriate based on the word context. There may be auditory feedback 81a and/or visual feedback 81b on each joystick movement or button press. For example, as soon as the joystick direction is registered, a solid or gradient-fill pie wedge shape could appear on the keyboard, centered on the current direction of tilt. Further, the width of that pie wedge could narrow in proportion to the tilt of the joystick towards the perimeter. The pie wedge can remain momentarily after the joystick is returned to its center/resting position. The pie wedge provides a visual cue that the tilt of the joystick was registered and reinforces the notion that each action represents a range of possible letters. FIG. 7 is a schematic view 90 of a selective input system 30 based on exemplary movement 38 and time-based tracking 48, e.g. relative or absolute, of a pointing device 16. As seen in FIG. 6, movement parameters and/or position parameters are readily made in two or three dimensional systems 92, such as in an orthogonal-axis coordinate system 92a, a cylindrical coordinate system 92b, or a spherical coordinate system 92k. SloppyType™ in Selective Input Systems. Several embodiments of the selective input system 30, such as systems 30a-30d, as seen in FIG. 3 through FIG. 7, preferably comprise enhanced disambiguation, such as but not limited to SloppyType™ disambiguation. For example, as shown in FIG. 3 and FIG. 6, the selective input system 30 may include a text display area 62, as well as a word choice list region 64 and/or a message area 66. The exemplary word choice list 64 typically comprises a list of words that the system 30 predicts as likely candidates based on the characters entered by ambiguous directional input. For example, the most likely word is a default word. The user can either accept the default word with one action, or select an alternate word with a combination of actions. The exact spelling sequence of exact characters coincidentally selected by the user is also displayed 66, e.g. 66a (FIG. 6). Preferably, the spelling sequence is displayed in a separate area 66a, such as above or below the word choice list 64. Alternatively, the spelling sequence may be displayed as an entry in the word choice list 64, typically the first line or the last line. In FIG. 6, the exact spelling sequence 66a is displayed above the word choice list 64. The last letter 20 entered may also be indicated or highlighted 81, such as on the on-screen keyboard and/or in the exact spell sequence, such as but not limited to font change, color change, reverse video or alternate background color, underline, bold face or italics, and outline. An example of a visual outline or highlight 81b can be a box or a circle. All the words on a word choice list 64, other than the exact spelling sequence at the time when the exact spelling sequence is displayed as the first or last entry, are ordered by a combination of the shortest calculated distances between the input entry sequence and each letter 20 in each word and the recency of use and/or the frequency of use within the given language. In various embodiments of the selective input system 30, a user can select a specific word from the word choice list, such as through a character/word selection area 64 (FIG. 3), a word choice list or application text editor 182a (FIG. 5), and/or through one or more supplementary controls 174a-174k (FIG. 11). Preferably, the method is consistent with other applications use of scrolling methods and selection button. The system typically comprises a means of selecting the exact spelling sequence as well as any predicted words. In one preferred embodiment, the system comprises a next button and a previous button, with which the user can navigate forward and backward through the word choice list. In some system embodiments, an “escape hole” 87 is provided, such as located on one or more input rings 83, e.g. 83a,83b (FIG. 6), that allows movement into the word list 64 or to system menus. As well, in some system embodiments, a default/accept character 89 is provided, such as located on one or more input rings 83, e.g. 83a,83b, or elsewhere on the onscreen keyboard 14c, for accepting a current default word and moving on, such as to the entry of another word. Alternatively, the selective input system 30 may include a selection mode switch button, such as through one or more buttons 71 (FIG. 4) or supplementary controls 174, e.g. 174a-174k (FIG. 11). When a selection mode switch button 71, 174 is pressed, the system enters a selection mode and the directional input means can be used to scroll forward and backward through the word choice list. In addition, selecting a predicted word using a particular means may replace the exact spelling sequence as if the letters of the selected word had been entered directly by the user, and a new list of predicted words is generated. The most likely word is the word added if the user does not try to select a different word. The default word may be a copy of the exact spelling sequence if the user was accurate. Alternatively, it may be the selected word as described above. In addition, the exact spelling sequence may become the default word if a precision method or mode (described below) is used to explicitly choose at least one letter in the sequence. Words that are longer than the number of input device actions registered in the current entry sequence may be included in the prediction list. Alternately, a further means can be provided to extend a selected word with completions. For example, longer words that begin with a selected word may appear on a pop-up list after a button press or directional input, similar to the cascading menus on PC windowing systems. Once a word is entered, the word is typically displayed in the message area 66a. Alternatively, the selective input system 30 can be implemented as an input method editor (IME). In this case, the text entered by the system goes into whatever program is actively accepting input from the system. Other applications may be linked to the system, or the system may be incorporated as part of another application. These applications include but are not limited to: instant messaging, electronic mail, chat programs, web browsing, communication within a video game, supplying text to a video game, as well as word processing. To enter a text message using some embodiments of the selective input system 30, such as but not limited to system 30 shown in FIG. 7, the user points the input device 14 in the general direction of the desired letter, and then continues pointing roughly to each letter in the desired word. Once all letters have been roughly selected, buttons may preferably be used to select a specific word from the list of potential matches. The selected word goes into the message area 66a, which may be an appropriate text application such as email or instant message. In some three dimensional systems 30, true motion 38 in respect to a z-axis 18c is tracked. In alternate embodiments, such as seen in FIG. 4, through pressure sensitive input from a trackpad 72a, a tablet 72b, or a joystick 72k, pressure-sensitive input information can preferably be used to determine motion and position in respect to three dimensions 92 (FIG. 7), such as in respect to a Z-axis 18c. The selective input system 30 and associated method 98 are not limited to require unistroke entry, i.e. one single continuous gesture, for a word. The system can piece together any single to multi-region sequences, and wait for the user to choose the best word choice. For example, within an alphanumeric entry area 75, for the entry of the word “hello”, the user can drag the stylus 16 from “h” to “e”, then tap twice on “l”, and stroke up to “o”. Some preferred embodiments of the selective input system 30 further comprise supplementary input 166 (FIG. 10), such as a printed or actual keyboard or keypad 166. Alternatively, a representation of the location 34 of the pointing device 16 over a virtual keyboard or keypad 166 can be dynamically shown on an associated display 144 (FIG. 10). FIG. 8 is a flowchart of an exemplary process 98, implemented on a computer, such as the device 12 or processor 73 (FIG. 4), 142 (FIG. 9, FIG. 10), for device tracking and character input 118 based on the tracking. The system 30 and associated process 98 identify character selections, by detecting changes in direction, changes in velocity, and/or pauses, at locations that correspond to features on the keyboard or keypad. The motion of a pointing device 16 is tracked 100 over an input region 14, such that the current position 34 of the device 16 is determined 102 at subsequent times 36, thereby defining a device path 38. Once the location 34 and associated time 36 is determined, the location 34 and associated time 36 are compared 104 to path data 38. At decision step 106, the process determines if the current location 34 and associated time 36 meet a threshold of a selectable position or character 20, e.g. such as if the pointing device 16 has changed in direction, changed in velocity, or stopped at a location that corresponds to a feature 20 within the area 14, such as corresponding to a the keyboard or keypad element 20. If the threshold decision is negative 108, the process returns 60 and continues to track 100 the motion. While the exemplary process 98 describes a comparison between a single the location 34 and associated time 36 to the path, one or more points can be analyzed, e.g. such as the current location 34 and the last three to five locations 34, to determine if a discernable selective motion has been made by the user. If the threshold decision is positive 112, the process decides 114 if the selected position 34 adequately indicates a selected item or character 20, e.g. such as if the identified position 34 is located within or sufficiently near the bounds of a selectable item or character 20. If a selectable item or character 20 is indicated 116, the selected item 20 is entered 118, and the process returns 110 and continues to track 100 the motion. If a selectable item or character 20 is not 120 sufficiently indicated, or if the system 30 determines 130 that an alternate selection 130 may be a valid or more valid choice, some embodiments of the process 98 disambiguate 122 the selection 34,36 if possible 124, and return to track 100 the motion. If an attempt to disambiguate 122 is not successful 126, the system 30, 98 may return to track 100 the motion, such as b y passing over the position, entering a blank character, or prompting the user to correct or reenter the intended selection 20, either by the pointing device 16, or through supplementary input 166 (FIG. 10). The disambiguation process 122 may comprise a determination of the closest selectable character or item 20, a determination of a group of selections 20, e.g. a word, or a determination one or more likely selections 20, by which a user can either choose from the determined likely selections 20, or may otherwise enter a corrected selection 20. The disambiguation process 122 may alternately comprise a selection of a position or vicinity in the region of multiple characters 20, as opposed to focusing on the selection of a single character 20. In some embodiments of the input system 30 and associated process 98, the disambiguation function 122 comprises a text disambiguation system 122, such as a T9® or Sloppytype™ disambiguation system 122, to improve the accuracy and usability of the input system 30. Details regarding disambiguation systems and processes 122 are seen in U.S. Patent No. 5,818,437, entitled REDUCED KEYBOARD DISAMBIGUATING COMPUTER; U.S. application Ser. No. 10/677,890, filed 01 Oct. 2003, entitled DIRECTIONAL INPUT SYSTEM WITH AUTOMATIC CORRECTION; U.S. application Ser. No. 09/580,319, filed 26 May 2000, entitled “KEYBOARD SYSTEM WITH AUTOMATIC CORRECTION”; and U.S. Provisional Application 60/461,735, filed 09 Apr. 2003, entitled “DIRECTIONAL SLOPPY TYPE”, which are incorporated herein by reference. FIG. 9 is a block schematic diagram 140 illustrating an exemplary selective input system 30 which comprises disambiguation functionality, according to a preferred embodiment of this invention. The selective input system 30 shown in FIG. 9 includes an analog input device 14, e.g. such as a joystick 72k (FIG. 4), preferably also comprising one or more buttons 71 (FIG. 4), an external information module 152 which typically stores a collection of linguistic objects, e.g. words and/or phrases, a display device 144 having a text display area, and a processor 142. The processor 142, which connects the other components together, further includes an object search engine 145, a motion and position calculation module 147 for calculating distance values, a word and phrase (linguistic object) module 148 for evaluating and ordering words, and a selection component 150. The system 30 may further comprise an optional on-screen representation of a keyboard 75 (FIG. 4) viewable through the display device 144. As described above, some preferred system embodiments 30 comprise text disambiguation functionality, such as to disambiguate the intended selection 20 of a device, or to provide a user with possible selection choices 20 for one or more selectable characters 20 that are determined to be possible selections, or with word or phrase choices 148 that may potentially be represented by the selection sequence. For example, on a standard QWERTY keyboard 166 (FIG. 10), selectable buttons 20 for the letters “R”, “T”, “F”, and “G” are located relatively close. For a determined position 24,34 of a pointing device 16 that lies close to the adjoining region of the letters “R”, “T”, “F”, and “G”, e.g. location 24m (FIG. 1), a text disambiguation module 72 may determine the likely choices “R”, “T”, “F”, and “G”, such as within the display 144, whereby a user may readily choose the listed word that includes the intended selection 20 in the proper position in the character sequence. FIG. 10 is a schematic view 160 of preferred processing 142, input 146, and display 162 systems associated with an input system 30d based on the tracking of absolute positions of a pointing device 16. The supplementary input 166 typically comprises a printed or actual keyboard or keypad 166. Alternatively, a representation of the location 24,34 of the pointing device 16 over a virtual keyboard or keypad 166 can be dynamically shown on an associated display 144. As seen in FIG. 10, a display 144 may be used to display 168 one or more determined selected characters 20, e.g. the misspelled word “Gitaffe”, wherein the exemplary determined position 34 of a pointing device 16 for the third letter 170 is “t”. In some system embodiments 30, the determined characters 20 are displayed for a user, such that a user may edit one or more selections 20. For example, as seen in FIG. 10, a user may change the third letter “t” to an “r”, to produce a corrected word group “giraffe” 164, such as through selection of alternate words from a word list, or through cursor selection 170 of one or more letters or characters, and entry of a desired letter or character 164, typically through reentry of the pointing device 16, or through the secondary input 166. The input device 14,72 serves as a selection input device, which provides a possibility of directional input with a sufficient precision, preferably 10 degrees or more precise. It may preferable that the default position of the cursor 79 (FIG. 4), if it is shown, is within an active region within a viewable display 144, such as at the center of an onscreen region 75. It is possible to use a joystick device to navigate in two dimensions an on-screen “QWERTY” or “ABC” keyboard, either in the standard rectangular form or in a circular layout. It is also possible to navigate through multiple concentric rings of characters. Although an analog joystick 72k is described as the selection device 14 in the selection system 160 shown in FIG. 10, any input device 14 that provides the possibility of directional input with a sufficient precision can be used. For examples: omni-directional rocker switch, thumbstick, e.g. IBM TrackPoint™, touchpad, touchscreen, touchscreen and stylus combination, trackball, eye tracking device, trapped-disk sliding switch, steering wheel, Apple iPod™ Navigation Wheel, or Sony's Jog-dial and data glove, e.g. old Nintendo Game Glove, can be used as alternatives. The input system 30 shown in FIG. 10 provides a method for precisely choosing the letters of a word. The method is useful for entering uncommon names and any word that is not part of the standard language currently active. The method can also be used to change the last character entered by stepping between characters adjacent to the last character entered. To step between characters adjacent to the last character entered, supplementary input 166, such as a forward button and/or a backward button may be used. Once the character 170 entered has been changed 164, the word choice list refreshes to reflect the changes in the predicted words. Alternatively, the system may be switched to a precision mode and the directional input means may be used to cycle through letters. For example, in a joystick configuration 72k (FIG. 6), to switch to the precision mode, the system may choose to use the degree of joystick tilt from the center. Once the tilt exceeds a preconfigured limit, the system 30 switches to the precision mode. Alternatively, the system 30 may use the time interval that the joystick dwells at the perimeter. Once the time interval reaches a preconfigured limit, the system switches to the precision mode and notifies the user through a visual cue or a tone. The system may also include a button for switching to precision mode. For example, as seen in FIG. 10, a user may change the third letter “t” to an “r”, to produce a corrected word group “giraffe” 164, such as through selection of alternate words from a word list, or through cursor selection 170 of one or more letters or characters, and entry of a desired letter or character 164, typically through reentry of the pointing device 16, or through the secondary input 166. The linguistic objects that are stored in the information module 152 (FIG. 9) typically comprise but are not limited to: words, phrases, abbreviations, chat slang, emoticons, user IDs, URLs, and/or non-English (such as Chinese or Japanese) characters. Although words are used in the preferred embodiments, any other linguistic objects are equally applicable. Similarly, although the term “letter” or “character” is used in the preferred embodiment, other sub-word components from Non-English languages, e.g. strokes, radicals/components, jamos, kana, plus punctuation symbols and digits, are equally applicable. The list of predicted or alternate words is typically ordered in accordance with a linguistic model, which may include one or more of: frequency of occurrence of a word in formal or conversational written text; frequency of occurrence of a word when following a preceding word or words; proper or common grammar of the surrounding sentence; application context of current word entry; and recency of use or repeated use of the word by the user or within an application program. One or more techniques can be implemented within a disambiguation process 122 (FIG. 8). In some situations, even if one or more characters are clearly indicated and selected, the disambiguation process 122 may reject the word, e.g. such as characters within a misspelled word, and offer a choice of correctly spelled alternate words, or may automatically replace the word, e.g. such as for commonly mistyped words or transposed letters. For example, in a situation in which a user USR has clearly entered an “S”, the disambiguation process may suggest an “A” or a “D”, such as for choices of one or more neighboring selectable characters 20 in a QWERTY keyboard, which may be determined to be logical. Therefore, even if a user USR precisely enters or indicates a selectable position 20, the disambiguation process 122 may provide one or more determined optional choices, e.g. by presenting the user with a display note, such as “Is this alternative choice what you meant to enter?”. As well, the disambiguation process 122 may determine a selection motion at a position which does not clearly indicate a selected position 20 within the input region 14. While the disambiguation process 122 is readily adapted to provide spell checking, the process 122 can also provide other disambiguation. For example, after entering a complete word or phrase, i.e. following a path 38 that returns multiple character candidates 20 at each spot 34 along the path 38, individual “selected positions 20 can be disambiguated with multiple mechanisms, wherein the mechanism typically uses context, such as the current input or display language, adjacent characters or words, previously used words or phrases, and/or known words or phrases. Alternate System Embodiments. FIG. 11 is a schematic view 171 of an alternate selective input system 30e based on the tracking of absolute positions of a pointing device 16, wherein functional sets 176, e.g. 176a, 176b, of selectable characters 20 of an input region 14 are changeable, such as based on stylus input 172 and/or device controls 174a-174k. For example, the selectable characters 20 may readily be changed in function to alternate characters 20, and may also be associated with different display characters. For example, stylus input 172 and/or device controls 174a-174k may be used as a shift, option, or control keys, whereby selectable characters are replaced with alternate characters. In alternate system embodiments 30e, a user does not have to explicitly select an input method, i.e. a set 176 of selectable characters. For example, by simply using the provided interface, such as through screen entry or by pressing one or more keys, the system may automatically switch or adjust to an alternate input set 176. In alternate embodiments of the selective input system 30, wherein characters or locations are selected, the system 30 preferably provides means for successive or repeated entry of one or more selectable items, characters, and/or locations, such as through action of a pointing device 16, e.g. a loop 44 on or near a selectable item 20, followed by a tap 19 in the same region. As well, supplementary input, such as but not limited to stylus input 172 and/or device controls 174a-174k, can be used for successive or repeated entry of one or more selectable items, characters, and/or locations. In alternate embodiments of the selective input system 30, entire keyboard arrangements are readily changed, such as to be suitable for an intended function, or based upon the preference of a user. For example, the design of a QWERTY keyboard set 176, can be changed to a DVORAK keyboard set 176, or a phone directory interface set 176 can be changed to a telephone keypad interface set 176. Similarly, all or part of the input screen area 14 may be used in combination with shorthand or character recognition type entry, e.g. Graffiti®. FIG. 12 shows a schematic view 180 of an alternate selective input system 30f, based on the tracking of absolute positions of a pointing device 16, wherein the input region 14 is changeable for function and/or appearance. For example, the device 12 is readily adapted to provide a plurality of different functions 182a-182j, through which the selective input system 30e tracks the motion parameters of a pointing device 16, e.g. such as but not limited to a text entry 182a, spell checking 182b, an alternate keyboard 182c, a schedule interface 182d, a to-do list 182e, or other graphic interfaces 182f,182j. As seen in to-do list interface 182e, a user may readily input desired priorities 186 on a group of tasks 184, such that the tasks 184 are readily rearranged, based on the tracked path 38. As seen in graphic area interface 182f, a user may readily input a desired travel itinerary 188, based on tracked travel path 186 on a map 190. Similarly, a graphic area interface 112j can display a game interface 192, whereby the tracking of motions and/or positions of a pointing device 16 determines game actions decisions and/or outcomes 194, such as success 194a and/or accumulated points 194b. FIG. 13 is a perspective view 200 of an alternate selective input system 30g based on the tracking of motion 38 of an input device through a region or volume 14. The selective input system 30f and associated method 98 are readily adapted to provide an input system based upon motion of an actual device 12, such as to detect two or three-dimensional motion in a variety of coordinate systems 92, e.g. 92a-92c. In the exemplary system 30f shown in FIG. 13, a user USR controllably moves an input device 12, such as but not limited to a stylus, PDA, cell phone, laser pointer, light pen, bare hand HD, a glove 204, or finger 12. For example, in a gaming system, a glove can be used for motion tracking. As well, while the exemplary system 30f shown in FIG. 13 shows the possible tracking of a bare hand HD or a gloved hand 204, other portions of the body of a person may be tracked, such as but not limited to a foot, a head, or other appendages. Similarly, while the exemplary system 30f shown in FIG. 13 shows the possible tracking of a glove 204, other accessories, tools, or articles of clothing 204 may alternately be used as a pointing device 12 for motion tracking, such as but not limited to a ring, a bracelet, a hat, a toy, or a wand. For example, the motion of a pointing tip of a play sword or wand 12 can be tracked, which can additionally be displayed on a projection screen 202, such as in context with a game scene. Upon detection of relative motion and path 38 and/or subsequent positions 34, the enhanced device 12 is readily used for a wide variety of applications, such as but not limited writing, game input, and/or control, either within the device itself 12, or in relation to other devices 202. In some alternate selective input systems 30g, the enhanced input device comprises accelerometers and/or a detection field for detection of relative motion and path 38 and/or subsequent positions 34. In other alternate selective input systems 30g, emitted light from laser pointer 12 is projected in relation to a projection screen 202, such as to provide a two-dimensional input. In yet another alternate selective input system 30g, emitted light from a light pen is detected on scan lines of a video screen 202, such as to provide an alternate two-dimensional input. In another alternate input system 30g, the motion of a user, e.g. a user's hand or finger, is tracked, such as by but not limited to a camera, radar, or lidar, such that no device needs to be held by the user USR. In the exemplary system 30g shown in FIG. 13, a user USR can cursively write a note, the motion of which is detected, calculated as an entry, disambiguated as necessary, and stored on the device 12. In a similar embodiment, a user can cursively enter a phone number or quick dial entry on an enhanced phone, receive acoustic feedback, such as a message of the intended number, e.g. “The phone number you entered is 555-555-1234”, and have the number dialed automatically. In an alternate embodiment, a user USR can cursively enter a desired cable channel, wherein the motion of which is detected, calculated as an entry, disambiguated as necessary, and sent to an external appliance or controller 202. In the selective input system 30g, the motion of input device 12 is tracked within the region or volume 14, while the user USR preferably gets visual feedback for the current “location” of the enhanced device 12, relative to the specific region or volume 14, to provide a plurality of different functions 182a-182j (FIG. 12), e.g. such as but not limited to a text entry 182a, spell checking 182b, an alternate keyboard 182c, a schedule interface 182d, a to-do list 182e, or other graphic interfaces 182f,182j. In some preferred embodiments of the selective input system 30g, the display 202 is separate from the input device 12, such as TV screen 202, e.g. for gaming or channel switching applications, or for a heads-up display 202. System Advantages. The selective input system 30 and associated method 98 provide significant advantages over existing character input systems, such that a user may quickly and intuitively enter one or more selections 20, even within a small interface area 14. In contrast to systems in which a user must repeatedly and accurately point or tap selections 20, the selective input system 30 and associated method 98 allow a much broader use of a pointing device 16, wherein the device 16 can be used in a variety of planar or non-planar movements to enter one or more selectable items or characters 20. While the selective input system 30 and associated method 98 can be used in combination with alternate methods of user input, e.g. stylus-based shorthand or handwriting recognition systems, the selective input system 30 and associated method 98 provide an intuitive entry system that can be used in many input environments. For example, the selective input method 48 can similarly be implemented on a planar keyboard, a keypad, or a telephone interface. Although the selective input system and methods of use are described herein in connection with personal computers, mobile devices, appliances, controls, and other microprocessor-based devices, such as portable digital assistants or network enabled cell phones, the apparatus and techniques can be implemented for a wide variety of electronic devices and systems, or any combination thereof, as desired. As well, while the selective input system and methods of use are described herein in connection with interaction between a two-dimensional input devices and systems, the character input system and methods of use can readily be implemented for selection within other dimensional systems, such as for one-dimensional slide controls, three-dimensional location or selection, or any combination thereof, as desired. Accordingly, although the invention has been described in detail with reference to a particular preferred embodiments, persons possessing ordinary skill in the art to which this invention pertains will appreciate that various modifications and enhancements may be made without departing from the spirit and scope of the invention and the claims that follow.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Input devices often comprise means for pointing or selecting, such as by a stylus, finger, or mouse, whereby a user may interact with a device. The user is often required to interact with a user interface, such as a keypad, touchpad, or touch screen, such as to input a desired character. A user typically maneuvers the pointing or selection device over a desired position over the interface, and then taps or sets the pointing device, to activate a chosen region or element, e.g. such as an actual or mapped keypad element or character. A user is often required to perform a large number of selective pointing actions, which can be difficult to perform, and are prone to error. Furthermore, the user interfaces for many devices are often small, such as for small electronic devices, e.g. portable cell phones, personal digital assistants (PDAs), or other devices often used for business, personal, educational, or recreational purposes. The selective pointing functions required to operate such small devices have become increasingly difficult and prone to error, as a user must accurately tap on a very small region within a user interface. Several structures and methods have been described, to facilitate the entry of information within stylus-based devices. For example, in a Palm personal digital assistant (PDA), available through Palm Inc., of Milpitas, Calif., a handwriting recognition system, such as Graffiti®, is provided, wherein a user, preferably with a stylus, enters shorthand-style simplified patterns within a designated entry region of an input screen. Entered motions are analyzed to determine the entered characters, which are then placed within an “active” or cursor region for the device. For example, for a cursor location corresponding to time, e.g. 2:30PM, within a schedule application, a user may enter “Meet with Fred”. Shumin Zhai and Per-Ola Kristensson, Shorthand Writing on Stylus Keyboard, Apr. 5-10, 2003, describe a method for computer-based writing, wherein a shorthand symbol is provided and taught for each word, according to a pattern on a stylus keyboard. A gesture pattern is typically made by tapping the first letter of a word, and gliding the stylus over to subsequent characters in a word. A word is recognized by the pattern of the gesture over the keyboard. Jennifer Mankoff and Gregory D. Abowd, Error Correction Techniques, submitted to Interact '99, provides a survey of the “design, implementation, and study of interfaces for correcting error prone input technologies”. Jennifer Mankoff and Gregory D. Abowd, Cirrin: A Word-Level Unistroke Keyboard for Pen Input, Proceedings of UIST 1998, Technical note. pp.213-214, describe a structure and method for planar entry of words, with a non-planar motion typically used between words. Keyboard designs are described, in which letters are arranged about the periphery of a neutral area. Each word is begun by starting a stylus path within a central, ie. neutral region. A user is then required to trace out a path which crosses, i.e. travels through, selected letters, while entering the central, neutral region as necessary, between successive letters. K. Perlin, Quikwriting: Continuous Stylus - Based Text Entry ; presented at A C M UIST'98 Conference, describes a shorthand for entering text, wherein the x,y positions of a stylus on a surface are tracked. The surface includes nine zones, including a central resting zone. A token is created whenever the stylus enters or exits any of the zones, and the sequence of tokens is used to determine the entered characters. The system typically requires that the stylus begin each word from a central resting zone. The system also often requires movement between two zones for the determined selection of most characters, while for characters which are defined to be “frequent”, the movement from a central resting zone to an outer zone and back to the resting zone can be used. M. Garrett, D. Ward, I. Murray, P. Cowans, and D. Mackay, Implementation of Dasher, an Information Efficient Input Mechanism , presented at LINUX 2003 Conference, Edinburgh, Scotland, describe a text entry system which uses “a language model to offer predictions to the user without constraining the range of words which can be written”, such as for “providing input on keyboardless devices and for disabled users”. The input system presents letters which move across a screen, wherein a user navigates a cursor into the zones for each letter. Zones for common letters, based on letters and words already presented, are bigger. Other work describing text input technologies is provided by P. Isokoski and R. Raisamo, Device Independent Text Input: A Rationale and an Example, Proceedings of the Working Conference on Advanced Visual Interfaces AVI2000, pages 76-83, Palermo, Italy, 2000; P. Isokoski, Text Input Methods for Eye Trackers Using Off - Screen Targets , In Proceedings of Eye Tracking Research & Applications Symposium 2000, pages 15-22. ACM, 2000; P. Isokoski, Model for Unistroke Writing Time , CHI Letters: Human Factors in Computing Systems, CHI 2001, 3(1):357-364, 2001; P. Isokoski and M. Käki. Comparison of Two Touchpad - Based Methods for Numeric Entry , CHI Letters: Human Factors in Computing Systems, CHI 2002, 4(1): 25-32, 2002; P. Isokoski and I. Scott MacKenzie, Text Entry on Mobile Systems: Directions for the Future , CHI 2001 Extended Abstracts, page 495, 2001; P. Isokoski and I. S. MacKenzie; Report on the CHI 2001 Workshop on Text Entry on Mobile Systems , SIGCHI Bulletin, p. 14, September/October 2001; P. Isokoski and I. S. MacKenzie. Combined Model for Text Entry Rate Development , CHI2003 Extended Abstracts, pp. 752-753, 2003; P. Isokoski and R. Raisamo, Architecture for Personal Text Entry Methods , In Closing the Gaps: Software Engineering and Human - Computer Interaction , pp. 1-8. IFIP, 2003. While such entry systems provide a means for entering information, the required shorthand or stylus paths are often complex, and movements required for one character are easily mistaken for different characters. A user is therefore often required to retype one or more characters, if the mistakes are even noticed. It would be advantageous to provide an input system that makes selection or character input based on determined motions of input device over an area, i.e. the individual characteristic motions which, as a whole, make up a pattern. The development of such a user input system would constitute a major technological advance. It would also be advantageous to provide a user input system, wherein selections of items or characters are determined, i.e. distinguished, by detecting parameters of motion of an input device, such as length of motion, a change in direction, a change in velocity, and/or a pause in motion, at locations that correspond to features on the keyboard/pad. The development of such a user input system would constitute a major technological advance. As well, it would be advantageous to provide an input system which makes selection or character input based on the motion of input device over an area, which is coupled to a text disambiguation system such as T9® or SloppyType™ system, to improve the accuracy and usability of the input system. The development of such a user input system would constitute a further major technological advance.
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<SOH> SUMMARY OF THE INVENTION <EOH>A selective input system and associated method are provided, which track the motion of an input device over an area. The input device can be a touchpad, a mouse, a pen, or any device capable of providing a location, e.g. such as an x-y location and/or a location based on alternate or additional dimensions. The area is preferably augmented with a printed or actual keyboard/pad. Alternatively, a representation of the location of the input device over a virtual keyboard/pad can be dynamically shown on an associated display. The system identifies selections of items or characters by detecting parameters of motion of the input device, such as length of motion, a change in direction, a change in velocity, and or a lack of motion at locations that correspond to features on the keyboard/pad. The input system is preferably coupled to a text disambiguation system, such as a T9® or SloppyType™ system, to improve the accuracy and usability of the input system.
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20040628
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20100706
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20050310
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77376.0
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KUMAR, SRILAKSHMI K
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SELECTIVE INPUT SYSTEM BASED ON TRACKING OF MOTION PARAMETERS OF AN INPUT DEVICE
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UNDISCOUNTED
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CONT-ACCEPTED
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10,881,946
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ACCEPTED
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Intraoral discluder and method for relieving migraine and tension headaches and temporomandibular disorders
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An intraoral discluder for preventing chronic tension headaches, common migraine headaches, and temporomandibular disorders that are caused or perpetuated by chronic activity of the temporalis muscle. The discluder includes a trough, contoured to encompass at least one maxillary or mandibular incisor, from which extends a protruding platform, for engagement by the opposing incisors. The trough can be retained on the teeth by any adaptable material than can flow around the teeth and then maintain its shape. Once in place in the wearer's mouth, one or two opposing incisors will come into contact with the platform prior to the upper and lower posterior and/or canine teeth coming into contact, regardless of the position of the mandible, thereby reducing the intensity of the activity of the temporalis muscle. In addition, a special post on the discluder's platform is engageable directly with one or more opposing incisors, to act as a stop and thereby inhibit excessive retrusive movement of the mandible and urge the mandible toward a more protrusive position. This can reduce the intensity of undesired clenching, and it can enhance the size of the wearer's pharyngeal airspace, thereby reducing the incidence and severity of snoring.
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1. An intraoral discluder comprising: a trough having an anterior wall and a posterior wall sized and configured to accommodate at least one upper or lower incisor, wherein the anterior wall is disposed adjacent to the incisor's anterior side and the posterior wall is disposed adjacent to the incisor's posterior side when the trough is disposed in the wearer's mouth; a platform attached to the trough and defining a contact surface that projects a substantial distance posteriorly from the trough's posterior wall when the trough is disposed in the wearer's mouth, wherein the contact surface is spaced sufficiently from the trough to prevent contact between opposing upper and lower teeth, whether the mandible is in a protrusive position or a retrusive position; and a post located at the posterior end of the platform and projecting in a direction away from the trough, wherein the post is sized and configured to be engageable directly with one or more opposing incisors, to inhibit excessive retrusive movement of the mandible. 2. An intraoral discluder as defined in claim 1, wherein the post is configured to inhibit excessive retrusive movement of the mandible sufficient to substantially enhance the pharyngeal airspace. 3. An intraoral discluder as defined in claim 1, wherein the trough, the platform, and the post are integral with each other. 4. An intraoral discluder as defined in claim 1, wherein the platform also projects a substantial distance anteriorly from the trough's anterior wall, when the trough is positioned in the wearer's mouth. 5. An intraoral discluder as defined in claim 1, wherein the platform's contact surface is substantially uniform along an anterior/posterior axis, when the discluder is positioned in the wearer's mouth, and the post is configured like a planar blade, projecting away from the contact surface. 6. An intraoral discluder as defined in claim 5, wherein the post has an anterior surface that defines an acute angle with the platform's contact surface. 7. An intraoral discluder as defined in claim 5, wherein the post's contact surface has a dimension that is substantially uniform in directions perpendicular to the anterior/posterior axis. 8. An intraoral discluder as defined in claim 1, wherein the trough is sized and configured to accommodate only the upper or lower incisors. 9. An intraoral discluder comprising: a trough having an anterior wall and a posterior wall sized and configured to accommodate at least one upper or lower incisor, wherein the anterior wall is disposed adjacent to the incisor's anterior side and the posterior wall is disposed adjacent to the incisor's posterior side when the trough is disposed in the wearer's mouth; a platform integral with the trough and defining an elongated, substantially uniform contact surface extending generally along an anterior/posterior axis when the discluder in positioned in the wearer's mouth, wherein the contact surface projects a substantial distance anteriorly of the trough's anterior wall and a substantial distance posteriorly of the trough's posterior wall, and wherein the contact surface is spaced sufficiently from the trough to prevent contact between opposing upper and lower teeth, whether the mandible is in a protrusive position or a retrusive position; and a blade-like post located at the posterior end of the platform and projecting in a direction away from the contact surface, wherein the post has an anterior surface that defines an acute angle with the contact surface, and wherein the post is sized and configured to be engageable directly with one or more opposing incisors, to inhibit excessive retrusive movement of the mandible thereby substantially enhance the pharyngeal airspace. 10. A method for preventing undesired contraction of the temporalis muscle, comprising the steps of: providing an intraoral discluder that includes, a trough having an anterior wall and a posterior wall sized and configured to accommodate at least one upper or lower incisor, wherein the anterior wall is disposed adjacent to the incisor's anterior side and the posterior wall is disposed adjacent to the incisor's posterior side when the trough is disposed in the wearer's mouth, a protruding platform attached to the trough and having a contact surface that extends a substantial distance posteriorly from the posterior wall of the trough when the trough is disposed in the wearer's mouth, wherein the contact surface is spaced sufficiently from the trough to prevent contact between opposing upper and lower teeth, whether the mandible is in a protrusive position or a retrusive position, and a post disposed at the posterior end of the protruding platform's contact surface and configured to project away from the contact surface; and placing the intraoral discluder on at least one of the wearer's upper or lower incisors so that at least one opposing incisor will contact the protruding platform and thereby prevent direct contact between wearer's upper and lower teeth, whether the mandible is in a protrusive position or a retrusive position; wherein the post is sized and configured to be engageable directly with one or more opposing incisors, to inhibit excessive retrusive movement of the mandible.
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BACKGROUND OF THE INVENTION The present invention relates generally to intraoral devices and, more particularly, to an intraoral discluder for use in relieving tension headaches, common migraine headaches, and temporomandibular disorders. Tension and muscle contraction headaches affect many people every day. The headaches are often recurring and, without effective treatment, can become very painful, restricting an individual's ability to think clearly and function effectively. The discomfort associated with tension and muscle contraction headaches is usually due to pain from strained and fatigued muscles of the head. The majority of the muscles of the human head are not sufficiently strong to elicit the type of pain and discomfort associated with tension and muscle contraction headaches. That is not the case with the temporalis muscle, however, which is located on the side of the skull and extends from just behind the eye to just behind the ear, and which is an extremely powerful muscle that functions to close or elevate the jaw. Under normal circumstances, the temporalis muscle should not exert a large static force by contracting isometrically, except possibly during normal chewing. Inappropriate isometric contraction of the temporalis muscle is commonly known as “clenching” and is clinically known as myofascial dysfunction. The intensity of the myofascial dysfunction varies according to the mandible's anterior/posterior position, with the intensity increasing as the mandible's position moves posteriorly. Unfortunately, myofascial dysfunction is particularly difficult to detect or diagnose, because the act of clenching is a relatively motionless act that is commonly done while a person is concentrating on another topic, or while sleeping. As the muscular contraction condition of “clenching” continues, the muscle becomes fatigued and susceptible to spasm and cramping. The pain from spasming and cramping temporalis fibers is severe and is usually diagnosed as a common migraine. Headache sufferers who seek the assistance of a physician typically are treated with muscle relaxants, analgesics, and/or physical therapy for the muscle fatigue. However, medications and physical therapy require continual treatment, and they treat only the symptoms of the underlying problem, not the source of the problem itself. Headache sufferers who seek the assistance of a dentist typically are diagnosed as having a temporomandibular disorder and are treated with an intraoral “jaw-positioning” appliance. Unfortunately, the intraoral appliances provided by dentists frequently are not entirely effective, because they only approximate the relative positions of the upper and lower teeth with respect to each other, allowing clenching to continue with minimal mandibular movement. Further, these intraoral appliances ordinarily cannot be used by patients who have malocclusions, protrusions or retrusions of the mandible, or other irregular teeth or mandibular orientations. Typically, the intraoral appliance must also be fabricated by a dentist at a prohibitive cost to a majority of individuals who suffer from tension headaches and common migraine headaches. Lastly, most intraoral jaw-positioning appliances and other types of semi-custom intraoral discluders can be used only on the upper teeth. However, in some circumstances, use of the appliance on the upper teeth is impossible due to malocclusions and irregular orientation of the teeth. One intraoral appliance that avoids the drawbacks mentioned immediately above is disclosed in U.S. Pat. No. 5,795,150 to Boyd, Sr. That appliance includes a trough sized and configured to be releasably retained by a wearer's maxillary incisors and further includes a dome projecting posteriorly from the trough and defining a surface to be contacted by at least one opposing incisor. When the appliance is properly positioned in the wearer's mouth, the temporalis muscles are rendered ineffective, thus relieving tension headaches, common migraine headaches, and temporomandibular disorders. However, it is believed that this appliance can sometimes still allow limited clenching of the temporalis muscle, particularly when the mandible is located in its furthest posterior position. It should be apparent from the foregoing discussion, that there remains a need for an even more effective intraoral discluder configured to be placed on either the upper teeth or the lower teeth, to prevent contact of the upper and lower teeth in all mandibular movements and to further inhibit undesired isometric contraction of the temporalis muscle. The present invention satisfies this need. SUMMARY OF THE INVENTION The present invention is embodied in an intraoral discluder, and related method for using it, configured not only to prevent contact of the upper and lower teeth in all mandibular movements, but also to inhibit excessive retrusive movement of the mandible, thereby reducing the intensity of undesired clenching and enhancing the size of the wearer's pharyngeal airspace. More particularly, the discluder includes a prefabricated trough having a anterior wall and a posterior wall sized and configured to accommodate at least one upper or lower incisor, and it further includes a platform attached to the trough and defining a contact surface that is spaced sufficiently from the trough to prevent contact between opposing upper and lower teeth, whether the mandible is in a protrusive position or a retrusive position. In addition, a post located at the posterior end of the platform is sized and configured to be engageable directly with one or more opposing incisors and thereby inhibit excessive retrusive movement of the mandible. In other, more detailed features of the invention, the post is configured to inhibit excessive retrusive movement of the mandible sufficient to substantially enhance the pharyngeal airspace. Preferably, the post is configured like a planar blade, projecting away from the contact surface with an anterior surface of the post defining an acute angle with the contact surface. The trough, platform, and post of the discluder preferably are formed integral with each other. The platform projects substantial distances both anteriorly from the trough's anterior wall and posteriorly from the trough's posterior wall, when the trough is positioned in the wearer's mouth. Further, the platform's contact surface is substantially uniform along an anterior/posterior axis, and it has a dimension that is substantially uniform in directions perpendicular to the anterior/posterior axis. Other features, and advantages of the present invention should become apparent from the following description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevation view of the human skull with a preferred embodiment of an intraoral discluder of the invention positioned over the maxillary incisors. FIG. 2 is a perspective view of the intraoral discluder of FIG. 1. FIG. 3 is a front elevational view of the intraoral discluder of FIG. 2, in place over the maxillary incisors, opposing the mandibular incisors. FIG. 4 is a front elevational view of the intraoral discluder of FIG. 2, in place over the mandibular incisors, opposing the maxillary incisors. FIG. 5 is a side sectional view of the intraoral discluder of FIG. 2, in place over a maxillary incisor with an adaptable material conforming to the shape of the maxillary incisor, opposing a mandibular incisor, with the mandibular incisor shown in both a protrusive and a retrusive position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to the exemplary drawings, and particularly to FIGS. 1 and 2, there is shown an intraoral discluder 10 in accordance with the invention. The discluder functions to prevent tension headaches, common migraine headaches, and temporomandibular disorders. With particular reference to FIG. 1, a schematic representation of a human skull 12 is shown, wherein the temporalis muscle 14 extends from the skull to its attachment 16 on the mandible 18. A contraction of the temporalis muscle causes the jaw to close. The discluder prevents the upper teeth 20 and the lower teeth 22 from contacting each other and thereby inhibits undesired contraction of the temporalis muscle. As shown in FIG. 2, the intraoral discluder 10 includes a trough 24 having an anterior wall 26 and a posterior wall 28. The trough has a slight arc shape, to match the typical curve of a wearer's upper or lower incisors. A protruding rail or platform 30 projects away from the trough, to define an elongated contact surface 32 extending in a direction generally perpendicular to the axis of the trough. The trough and the protruding platform can be integral with each other or, alternatively, can be separately formed and then attached to each other. In addition, the trough and the protruding platform both can be made of any suitable biocompatible material that will hold its form, e.g., polymers, enamels, rubbers, silicone resins, and any other conventional materials known to be used by those skilled in the art. Alternatively, the trough and the protruding platform can be made of different biocompatible materials selected from these same examples. FIG. 3 shows the intraoral discluder 10 in place over the maxillary incisors 34, with the contact surface 32 of the protruding platform 30 being contacted by the opposing mandibular incisors 36 when the mandible 18 (FIG. 1) elevates. The contact surface is positioned a sufficient distance from the trough 24 to prevent the opposing upper teeth 20 and lower teeth 22 from contacting each other. Typically, this distance is on the order of several millimeters. Alternatively, as shown in FIG. 4, the intraoral discluder 10 can be placed over the mandibular incisors 36, with the contact surface 32 of the protruding platform 30 contacting the opposing maxillary incisors 34 when the mandible 18 elevates. As in the case when the discluder is placed over the maxillary incisors, this prevents the opposing upper teeth 20 and lower teeth 22 from contacting each other. With reference now to FIG. 5, an adaptive material 38 can optionally be disposed within the trough 24, between the anterior wall 26 and the posterior wall 28, for conforming engagement with the maxillary incisors 34. This adaptive material can be made of any type of material that conforms and retains its shape, including, e.g., silicone resins, polymers, enamels, rubbers, and any other material known to be used by those skilled in the art. This material aids in providing a comfortable and durable engagement between the discluder 10 and the incisors. The protruding platform 30 is depicted to project both anteriorly and posteriorly from the trough 24. This ensures that the opposing mandibular incisors 36 will contact the platform's contact surface 32 regardless of whether the mandible 18 is in a protrusive position or a retrusive position. These two positions are depicted in FIG. 5, with the mandibular incisor being identified by the reference numeral 36 when in a protrusive position and by the reference numeral 36′ when in a retrusive position. Preferably, the contact surface has a length in the anterior/posterior direction in the range of about 8 mm to about 12 mm and a uniform transverse width of about 5 mm. The contact surface projects anteriorly from the anterior wall 26 of the trough by at least about 3 mm. With continued reference to FIG. 5, it will be noted that a blade-like post 40 projects away from the posterior end of the protruding platform 30. This post acts as a stop for the wearer's mandibular incisors 36, inhibiting excessive retrusive movement of the mandible 18 and urging the mandible toward a more protrusive position. This can serve two important functions. First, it can reduce the intensity of undesired clenching, and, second, it can enhance the size of the wearer's pharyngeal airspace, thereby reducing the incidence and severity of snoring. In an alternative embodiment, not depicted in the drawings, the intraoral discluder can include one or more extending tabs sized and configured for placement onto the protruding platform, thereby increasing the distance of the contacting surface from the trough. These tabs are selectively used if the wearer's mouth is configured such that the upper and lower teeth would otherwise contact each other before the opposing incisors would contact the platform. The extension tabs can be made of any suitable biocompatible material, including, e.g., silicone resins, polymers, enamels, rubbers, and any other material known to those skilled in the art. The extension tabs may be adhered to the entire platform, as shown, or to only a portion of it, and they can be adhered by any suitable means, e.g., adhesives, cutouts, prefabricated snap-in-place pieces, natural attraction, adhesion, or other any other suitable method known to those skilled in the art. In another alternative embodiment, not depicted in the drawings, the intraoral discluder can be configured to include one or more cutouts in the trough's anterior wall, for enhancing the retention of the adaptive material within the trough. Other structures for enhancing retention of the adaptive material can include mechanical undercuts, adhesives, and/or natural attraction of the adaptable material to the trough. It should be evident from the drawings and the discussion above that the intraoral discluder of the invention is effective in preventing the upper teeth and lower teeth from contacting each other. This, in turn, prevents undesired isometric contractions of the temporalis muscle, thereby minimizing the occurrence of tension headaches, common migraine headaches, and temporomandibular disorders. In addition, a special post on the discluder is sized and configured to be engageable directly with one or more opposing incisors, to act as a stop and thereby inhibit excessive retrusive movement of the mandible and urge the mandible toward a more protrusive position. This can reduce the intensity of undesired clenching, and it can enhance the size of the wearer's pharyngeal airspace, thereby reducing the incidence and severity of snoring. Although the invention has been described in detail with reference to the presently preferred embodiments, those of ordinary skill in the art will appreciate that various modifications can be made without departing from the invention. Accordingly, the invention is defined only by the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates generally to intraoral devices and, more particularly, to an intraoral discluder for use in relieving tension headaches, common migraine headaches, and temporomandibular disorders. Tension and muscle contraction headaches affect many people every day. The headaches are often recurring and, without effective treatment, can become very painful, restricting an individual's ability to think clearly and function effectively. The discomfort associated with tension and muscle contraction headaches is usually due to pain from strained and fatigued muscles of the head. The majority of the muscles of the human head are not sufficiently strong to elicit the type of pain and discomfort associated with tension and muscle contraction headaches. That is not the case with the temporalis muscle, however, which is located on the side of the skull and extends from just behind the eye to just behind the ear, and which is an extremely powerful muscle that functions to close or elevate the jaw. Under normal circumstances, the temporalis muscle should not exert a large static force by contracting isometrically, except possibly during normal chewing. Inappropriate isometric contraction of the temporalis muscle is commonly known as “clenching” and is clinically known as myofascial dysfunction. The intensity of the myofascial dysfunction varies according to the mandible's anterior/posterior position, with the intensity increasing as the mandible's position moves posteriorly. Unfortunately, myofascial dysfunction is particularly difficult to detect or diagnose, because the act of clenching is a relatively motionless act that is commonly done while a person is concentrating on another topic, or while sleeping. As the muscular contraction condition of “clenching” continues, the muscle becomes fatigued and susceptible to spasm and cramping. The pain from spasming and cramping temporalis fibers is severe and is usually diagnosed as a common migraine. Headache sufferers who seek the assistance of a physician typically are treated with muscle relaxants, analgesics, and/or physical therapy for the muscle fatigue. However, medications and physical therapy require continual treatment, and they treat only the symptoms of the underlying problem, not the source of the problem itself. Headache sufferers who seek the assistance of a dentist typically are diagnosed as having a temporomandibular disorder and are treated with an intraoral “jaw-positioning” appliance. Unfortunately, the intraoral appliances provided by dentists frequently are not entirely effective, because they only approximate the relative positions of the upper and lower teeth with respect to each other, allowing clenching to continue with minimal mandibular movement. Further, these intraoral appliances ordinarily cannot be used by patients who have malocclusions, protrusions or retrusions of the mandible, or other irregular teeth or mandibular orientations. Typically, the intraoral appliance must also be fabricated by a dentist at a prohibitive cost to a majority of individuals who suffer from tension headaches and common migraine headaches. Lastly, most intraoral jaw-positioning appliances and other types of semi-custom intraoral discluders can be used only on the upper teeth. However, in some circumstances, use of the appliance on the upper teeth is impossible due to malocclusions and irregular orientation of the teeth. One intraoral appliance that avoids the drawbacks mentioned immediately above is disclosed in U.S. Pat. No. 5,795,150 to Boyd, Sr. That appliance includes a trough sized and configured to be releasably retained by a wearer's maxillary incisors and further includes a dome projecting posteriorly from the trough and defining a surface to be contacted by at least one opposing incisor. When the appliance is properly positioned in the wearer's mouth, the temporalis muscles are rendered ineffective, thus relieving tension headaches, common migraine headaches, and temporomandibular disorders. However, it is believed that this appliance can sometimes still allow limited clenching of the temporalis muscle, particularly when the mandible is located in its furthest posterior position. It should be apparent from the foregoing discussion, that there remains a need for an even more effective intraoral discluder configured to be placed on either the upper teeth or the lower teeth, to prevent contact of the upper and lower teeth in all mandibular movements and to further inhibit undesired isometric contraction of the temporalis muscle. The present invention satisfies this need.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is embodied in an intraoral discluder, and related method for using it, configured not only to prevent contact of the upper and lower teeth in all mandibular movements, but also to inhibit excessive retrusive movement of the mandible, thereby reducing the intensity of undesired clenching and enhancing the size of the wearer's pharyngeal airspace. More particularly, the discluder includes a prefabricated trough having a anterior wall and a posterior wall sized and configured to accommodate at least one upper or lower incisor, and it further includes a platform attached to the trough and defining a contact surface that is spaced sufficiently from the trough to prevent contact between opposing upper and lower teeth, whether the mandible is in a protrusive position or a retrusive position. In addition, a post located at the posterior end of the platform is sized and configured to be engageable directly with one or more opposing incisors and thereby inhibit excessive retrusive movement of the mandible. In other, more detailed features of the invention, the post is configured to inhibit excessive retrusive movement of the mandible sufficient to substantially enhance the pharyngeal airspace. Preferably, the post is configured like a planar blade, projecting away from the contact surface with an anterior surface of the post defining an acute angle with the contact surface. The trough, platform, and post of the discluder preferably are formed integral with each other. The platform projects substantial distances both anteriorly from the trough's anterior wall and posteriorly from the trough's posterior wall, when the trough is positioned in the wearer's mouth. Further, the platform's contact surface is substantially uniform along an anterior/posterior axis, and it has a dimension that is substantially uniform in directions perpendicular to the anterior/posterior axis. Other features, and advantages of the present invention should become apparent from the following description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
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20040629
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20100202
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20051229
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67203.0
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DESANTO, MATTHEW F
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INTRAORAL DISCLUDER AND METHOD FOR RELIEVING MIGRAINE AND TENSION HEADACHES AND TEMPOROMANDIBULAR DISORDERS
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SMALL
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ACCEPTED
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10,881,995
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ACCEPTED
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Chemical, biological, radiological, and nuclear weapon detection system with alarm thresholds based on environmental factors
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A chemical, biological, radiological, and nuclear weapon detection system is disclosed that incorporates a mechanism to reduce the probability that a false alarm will be issued. In particular, the mechanism causes an alarm to be triggered when the amount of a hazardous material reaches a threshold, but changes the threshold based, at least in part, on environmental (e.g., meteorological, etc.) characteristics (e.g., whether is it precipitating or not, whether it is sunny or not, etc) that effect the efficacy of a chemical, biological, radiological, or nuclear weapon. Given that there are environmental factors that make an attack less effective, and given that terrorists are aware of this, the illustrative embodiment is less likely to issue an alarm when the environmental factors suggest that an attack is less effective, and, therefore, less likely. The illustrative embodiment accomplishes this by changing the threshold needed to issue an alarm based on one or more the environmental factors.
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1. A system comprising: a first environmental sensor for monitoring a first environmental characteristic; a first hazardous material sensor for measuring the amount of a first hazardous material; and a first alarm that is issued when the amount of said first hazardous material reaches a first threshold, wherein said first threshold changes and is based on said first environmental characteristic. 2. The system of claim 1 wherein said first environmental characteristic is precipitation. 3. The system of claim 2 wherein said first threshold is higher when it is precipitating than when it is not precipitating. 4. The system of claim 1 wherein said first environmental characteristic is humidity. 5. The system of claim 4 wherein said first threshold is higher when it is lower humidity than when it is higher humidity. 6. The system of claim 1 wherein said first environmental characteristic is sunlight. 7. The system of claim 6 wherein said first threshold is higher when it is night than when it is day. 8. The system of claim 1 wherein said first environmental characteristic is wind speed. 9. The system of claim 8 wherein said first threshold is higher when it is windy than when it is not windy. 10. The system of claim 1 further comprising a second environmental sensor for monitoring a second environmental characteristic; wherein said first threshold changes and is based on said first environmental characteristic and on said second environmental characteristic. 11. The system of claim 1 further comprising: a second hazardous material sensor for measuring the amount of a second hazardous material; and a second alarm that is issued when the amount of said second hazardous material reaches a second threshold, wherein said second threshold changes and is based on said first environmental characteristic. 12. A method comprising: monitoring a first environmental characteristic; measuring the amount of a first hazardous material; and issuing a first alarm when the amount of said first hazardous material reaches a first threshold, wherein said first threshold changes and is based on said first environmental characteristic. 13. The method of claim 12 wherein said first environmental characteristic is precipitation. 14. The method of claim 13 wherein said first threshold is higher when it is precipitating than when it is not precipitating. 15. The method of claim 12 wherein said first environmental characteristic is humidity. 16. The method of claim 15 wherein said first threshold is higher when it is lower humidity than when it is higher humidity. 17. The method of claim 12 wherein said first environmental characteristic is sunlight. 18. The method of claim 17 wherein said first threshold is higher when it is night than when it is day. 19. The method of claim 12 wherein said first environmental characteristic is wind speed. 20. The method of claim 19 wherein said first threshold is higher when it is windy than when it is not windy. 21. The method of claim 12 further comprising: monitoring a second environmental characteristic; wherein said first threshold changes and is based on said first environmental characteristic and on said second environmental characteristic. 22. The method of claim 12 further comprising: measuring the amount of a second hazardous material; and issuing a second alarm when the amount of said second hazardous material reaches a second threshold, wherein said second threshold changes and is based on said first environmental characteristic.
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FIELD OF THE INVENTION The present invention relates to civil defense in general, and, more particularly, to chemical, biological, radiological, and nuclear weapons detection systems. BACKGROUND OF THE INVENTION A chemical, biological, radiological, or nuclear attack on a civilian population is a dreadful event, and the best response requires the earliest possible detection of the attack so that individuals can flee and civil defense authorities can contain its effects. To this end, chemical, biological, radiological, and nuclear weapons detection systems are being deployed in many urban centers that will give civil defense authorities almost instant notification that an attack has occurred. SUMMARY OF THE INVENTION A terrorist seeks to impose his or her will on a government by convincing its citizenry that conciliation—and not confrontation—will make the threat disappear. If the government is able to protect its citizens from violence, the policy of confrontation will be deemed successful and the terrorist's agenda will be thwarted. In contrast, if the terrorist is able to strike wherever and whenever it desires, the policy of confrontation will be deemed unsuccessful and the terrorist's agenda will be promoted by those who favor conciliation. In either case, the government and the terrorist are locked in a struggle to undermine the citizenry's respect and confidence in the other. It warrants repeating that the salient traits that the government and the terrorists vie for are respect and confidence, and, therefore, any factor—however apparently remote—that enhances or detracts either's respect and confidence is important. One way that the government earns and maintains the respect and confidence of the citizenry is by quickly and accurately informing the public when an attack has occurred and by taking the appropriate action. This means that there are two ways in which the government can lose the respect and confidence of the citizenry. First, the government can fail to inform the public when an actual attack has occurred, and second, the government can inform the public that an attack has occurred when in fact there has been so such attack. Therefore, it's important for the government to inform the public of an attack when an attack has in fact occurred, but that it is also important for the government not to issue false alarms. To this end, the respect in the government is best enhanced by a chemical, biological, radiological, and nuclear weapon detection system that both: (1) quickly issues an alarm in the event of a real attack, and (2) accurately withholds false alarms. The illustrative embodiment of the present invention incorporates a mechanism to reduce the probability that a false alarm will be issued. In particular, the mechanism causes an alarm to be triggered when the amount of a hazardous material reaches a threshold, but changes the threshold based, at least in part, on environmental (e.g., meteorological, etc.) characteristics (e.g., whether is it precipitating or not, whether it is sunny or not, etc) that effect the efficacy of a chemical, biological, radiological, or nuclear weapon. For example, it is well understood that a chemical gas attack is likely to be less effective when it is raining than when it is clear because the rain will suppress and dilute the chemical agent. Given that there are environmental factors that make an attack less effective, and given that terrorists are aware of this, the illustrative embodiment is less likely to issue an alarm when the environmental factors suggest that an attack is less effective, and, therefore, less likely. The illustrative embodiment accomplishes this by changing the threshold needed to issue an alarm based on one or more the environmental factors. The illustrative embodiment comprises: a first environmental sensor for monitoring a first environmental characteristic; a first hazardous material sensor for measuring the amount of a first hazardous material; and a first alarm that is issued when the amount of the first hazardous material reaches a first threshold, wherein the first threshold changes and is based on the first environmental characteristic. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a city map and the location of the salient components of the illustrative embodiment of the present invention on that map. FIG. 2 depicts a block diagram of the salient components of each of environmental sensor arrays 101-1 through 101-17. FIG. 3 depicts a block diagram of the salient components of each of video camera clusters 102-1 through 102-13. FIG. 4 depicts a block diagram of the salient components of each of hazardous material detection stations 103-1 through 103-11. FIG. 5 depicts a block diagram of the salient components of hazardous material sensor array 401-k. FIG. 6 depicts a block diagram of the salient components of hazardous material station processor 402-k. FIG. 7 depicts a block diagram of the salient components of system control center 110. FIG. 8 depicts a flowchart of the salient tasks associated with the deployment and operation of the illustrative embodiment. FIG. 9 depicts a flowchart of the salient tests in task 805 of FIG. 8. FIG. 10 depicts a flowchart of the salient tasks associated with the operation of hazardous material detection processor 402-k. FIG. 11 depicts the threshold for VX Gas in parts per million (ppm) as a function of both precipitation and whether or not it is sunny. DETAILED DESCRIPTION FIG. 1 depicts a city map and the location of the salient components of the illustrative embodiment of the present invention on that map. The illustrative embodiment comprises: i. seventeen (17) spatially-disparate environmental sensor arrays 101-1 through 101-17, ii. thirteen (13) spatially-disparate video camera clusters 102-1 through 102-13, iii. eleven (11) spatially-disparate hazardous material detection stations 103-1 through 103-11, and iv. system control center 110. Environmental sensor arrays 101-1 through 101-11 and video camera clusters 102-1 through 102-11 are not distinctly shown in FIG. 1 because they are co-located with and contained within hazardous material detection stations 103-1 through 103-11, respectively. Environmental sensor arrays 101-1 through 101-17, video camera clusters 102-1 through 102-13, and hazardous material detection stations 103-1 through 103-11 are deployed throughout city 100 to enable the comprehensive environmental, video, and hazardous material surveillance of city 100. In accordance with the illustrative embodiment, all of environmental sensor arrays 101-1 through 101-17, video camera clusters 102-1 through 102-13, and hazardous material detection stations 103-1 through 103-11 are outdoors, but after reading this specification it will be clear to those skilled in the art how to make and use embodiments of the present invention in which some or all of the environmental sensor arrays, video camera clusters, and hazardous material detection stations are indoors. Furthermore, although the illustrative embodiment is depicted as deployed in an urban environment, it will be clear to those skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention that are deployed or deployable in other environs (e.g., on ship board, in a rural area, in suburbia, etc.). Each of environmental sensor arrays 101-1 through 101-17 monitors eight environmental characteristics (e.g., precipitation, humidity, sunlight, temperature, wind speed, wind direction, barometric pressure, ambient sound, etc.) at a different location and reports its findings to system control center 110. Furthermore, each of environmental sensor arrays 101-1 through 101-11 reports its findings to hazardous material detection stations 103-1 through 103-11, respectively. In accordance with the illustrative embodiment, the reporting is accomplished through wireline telemetry in well-known fashion. It will be clear to those skilled in the art, however, after reading this specification, how to make and use alternative embodiments of the present invention in which some or all of the reporting is accomplished through wireless telemetry. The details of environmental sensor arrays 101-1 through 101-17 are described below and with respect to FIG. 2. Each of video camera clusters 102-1 through 102-13 monitors a location, in well-known fashion, and transmits its video signals to system control center 110 via wireline telemetry. It will be clear to those skilled in the art, however, how to make and use alternative embodiments of the present invention in which some or all of the video signals are transmitted via wireless telemetry. The details of video camera clusters 102-1 through 102-13 are described below and with respect to FIG. 13. Each of hazardous material detection stations 103-1 through 103-11 measures the amount of six (6) hazardous materials (e.g., nuclear warfare agents, chemical warfare agents, biological warfare agents, etc.) and transmits an alarm status for each hazardous material to system control center 110 via wireline telemetry. It will be clear to those skilled in the art, however, how to make and use alternative embodiments of the present invention in which some or all of the alarms are transmitted via wireless telemetry. Although each of hazardous material detection stations 103-1 through 103-11 detects six (6) hazardous materials, it will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that detect any number of hazardous materials. The details of hazardous material detection stations 103-1 through 103-11 are described below and with respect to FIGS. 4 through 6. Although the illustrative embodiment comprises 17 environmental sensor arrays, 13 video camera clusters, and 11 hazardous material detection stations, it will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that comprise any number of environmental sensor arrays, video camera clusters, and hazardous material detection stations. Furthermore, it will be clear to those skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention in which one or more of the hazardous material detection stations lacks a video camera cluster or an environmental sensor array or both. System control center 110 receives the telemetry from environmental sensor arrays 101-1 through 101-17, video camera clusters 102-1 through 102-13, and hazardous material detection stations 103-1 through 103-11 and determines, in the manner described below, whether or not to issue a system-wide alarm. The operation of environmental sensor arrays 101-1 through 101-17, video camera clusters 102-1 through 102-13, hazardous material detection stations 103-1 through 103-11, and system control center 110 are described in detail below and with respect to FIGS. 8 through 11. FIG. 2 depicts a block diagram of the salient components of each of environmental sensor arrays 101-1 through 101-17. Environmental sensor array 101-i, for i=1 through 17, comprises: i. precipitation sensor 201-i-1, ii. humidity sensor 201-i-2, iii. sunlight sensor 201-i-3, iv. temperature sensor 201-i-4, v. wind speed sensor 201-i-5, vi. wind direction sensor 201-i-6, vii. barometric pressure sensor 201-i-7, and viii. ambient sound sensor 201-i-8. The illustrative embodiment measures these eight environmental factors because each of them can—for the reasons described below—be correlated to the efficacy, and, therefore, the likelihood of a chemical, biological, radiological, or nuclear weapons attack. In accordance with the illustrative embodiment, each of environmental sensor arrays 101-1 through 101-17 comprises the same eight sensors. It will be clear to those skilled in the art however, after reading this specification, how to make and use alternative embodiments of the present invention in which each sensor array has any subset of these sensors. Furthermore, it will be clear to those skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention that measure one or more additional environmental factors that can be correlated to the efficacy, and, therefore, the likelihood of a chemical, biological, radiological, or nuclear weapons attack. The output of each sensor is multiplexed into environmental telemetry feed 202-i in well-known fashion and transmitted to system control center 110 and, for k=1 through 11 to hazardous material station alarms 402-k, respectively. It will be clear to those skilled in the art how to make each of environmental sensor arrays 101-1 through 101-17. FIG. 3 depicts a block diagram of the salient components of each of video camera clusters 102-1 through 102-13. Video camera cluster 102-v, for v=1 through 13, comprises: video camera #1, video camera #2, and video camera #3. The output of each camera is multiplexed in well-known fashion and transmitted to system control center 110 via wireline telemetry feed 302-v. It will be clear to those skilled in the art how to make each of video camera clusters 102-1 through 102-13. In accordance with the illustrative embodiment, each of video camera clusters 102-1 through 102-13 comprises three cameras. It will be clear to those skilled in the art however, after reading this specification, how to make and use alternative embodiments of the present invention in which each video camera cluster has any number of video cameras (including only one (1) camera). FIG. 4 depicts a block diagram of the salient components of each of hazardous material detection stations 103-1 through 103-11. Hazardous material detection station 103-k, for k=1 through K, comprises: i. hazardous material sensor array 401-k, ii. hazardous material station processor 402-k, iii. environmental sensor array 101-k, and iv. video camera cluster 102-k, interconnected as shown. Hazardous material sensor array 401-k comprises six hazardous material sensors for measuring the amount of alpha particles, beta particles, anthrax, small pox, sarin gas, and VX gas present at the array. In accordance with the illustrative embodiment of the present invention, hazardous material sensor array 401-k receives measurements on the current environmental factors from environmental sensor array 101-k and uses them to determine how frequently—and with what sensitivity—it should sample the ambient environment for the hazardous materials. This is because a chemical, biological, radiological, or nuclear attack is more likely to occur when some environmental factors are present than at other times, and, therefore, the illustrative embodiment is more diligent in looking for an attack when the environmental factors are more favorable for an attack. Hazardous material sensor array 401-k does not determine whether the amount of a measured hazardous material should trip an alarm; this is performed by hazardous material station processor 402-k. To this end, the measurements made by hazardous material sensor array 401-k are transmitted to hazardous material station processor 402-k via wireline feed 411-k. The details of hazardous material sensor array 401-k are described below and with respect to FIG. 5. Hazardous material station processor 402-k takes the measurements from hazardous material sensor array 401-k and the measurements from environmental sensor array 101-k and determines whether or not to transmit a “station” alarm to system control center 110 via wireline telemetry feed 412-k. In accordance with the illustrative embodiment, an alarm is not issued when the measured amount of a hazardous material reaches a static threshold. Instead, an alarm is issued when the amount of a hazardous material reaches a dynamic threshold, wherein the threshold changes and is based on at least one environmental factor. The purpose of having the threshold change as a function of one or more environmental factors is to recognize that a chemical, biological, radiological, or nuclear attack is more likely to occur when some environmental factors are present than at other times, and, therefore, the threshold for issuing an alarm should lower when the environmental factors are more favorable for an attack than when the factors are unfavorable for an attack. The threshold for each hazardous material can be changed independently of the threshold for the other hazardous materials, and the threshold for each threshold can be determined using a different function of the environmental factors. The details of hazardous material station processor 402-k are described in detail below and with respect to FIG. 6. Hazardous material station processor 402-k comprises a general-purpose digital processor that performs an adaptive algorithm that sets the dynamic threshold based on measurements from environmental sensor array 101-k. In some alternative embodiments of the present invention, hazardous material station processor 402-k is a neural network. FIG. 5 depicts a block diagram of the salient components of hazardous material sensor array 401-k, which comprises: i. alpha particle sensor 501-k-1, ii. beta particle sensor 501-k-2, iii. anthrax sensor 501-k-3, iv. small pox sensor 501-k-4, v. sarin gas sensor 501-k-5, and vi. VX gas sensor 501-k-6, interconnected as shown. Each of the six sensors is a point sensor and receives one or more measurements of the current ambient environment factors as observed by environmental sensor array 101-k and uses them to change the schedule or when—and with what care—it should sample the ambient environment for its specific hazardous material. In some alternative embodiments of the present invention, one or more of the sensors are stand-off sensors, in contrast to point sensors, and it will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention which comprise point sensors, stand-off sensors, or a combination of point sensors and stand-off sensors. In general, a chemical, biological, radiological, or nuclear attack is more likely to occur: i. when it is not precipitating (e.g., raining, snowing, sleeting, etc.) because the precipitation frustrates the dissemination and enervates the efficacy of the hazardous materials; ii. when it is lower humidity, for the same reasons; iii. when it is night (i.e., there is no sunlight) because the sunlight tends to breakdown the biological and chemical agents, because attacks are more psychologically terrifying at night, and because inversion layers typically occur at night; iv. when the temperature is not extreme; v. when the wind is blowing because the wind helps to the disseminate the hazardous materials; vi. when the wind is blowing in a constant direction because it also helps to disseminate the hazardous materials; vii. when a rising barometric pressure suggests that fair weather is coming; and viii. shortly after a sound that could be caused by a chemical explosion. Therefore, the schedule for checking for each hazardous material should be faster or more frequent when the conditions are ripe for an attack with that type of material. The rate for checking for each hazardous material can be different than the rate for the other hazardous materials, and the rate for checking for each hazardous material can be a different function of environmental factors. After reading this specification, it will be clear to those skilled in the art how to make and use alpha particle sensor 501-k-1, beta particle sensor 501-k-2, anthrax sensor 501-k-3, pox sensor 501-k-4, sarin gas sensor 501-k-5, and VX gas sensor 501-k-6. FIG. 6 depicts a block diagram of the salient components of hazardous material station processor 402-k, which comprises: i. alpha particle station alarm 601-k-1, ii. beta particle station alarm 601-k-2, iii. anthrax station alarm 601-k-3, iv. small pox station alarm 601-k-4, v. sarin gas station alarm 601-k-5, and vi. VX gas station alarm 601-k-6, interconnected as shown. Each of these six station alarms receives: i. one or more measurements of the current ambient environment factors as observed by environmental sensor array 101-k, and ii. a stream of measurements from its corresponding sensor in hazardous material sensor array 401-k, and uses them to determine when an alarm for that hazardous material should be transmitted to system control center 110 via wireline 411-k. Each of the six station alarms is issued when the amount of a hazardous material reaches a threshold, and an alarm is stopped when the amount of the hazardous material falls below the threshold. A station can issue one or more alarms concurrently. The thresholds are not static, however, but change and are at least partially based on one or more of the measurements of the current ambient environment factors as observed by environmental sensor array 101-k. In particular, a chemical, biological, radiological, or nuclear attack is more likely to occur when some environmental conditions are present, and, therefore, the individual thresholds for each alarm are higher when those environmental conditions do not exist. For example, the threshold for sarin as is higher when it is precipitating than when it is not precipitating, lower when it is lower humidity than higher humidity, lower when it is night than when it is day, and lower when it is windy than when it is not windy. The operation of hazardous material station processor 402-k is described in detail below and with respect to FIGS. 8 through 11. FIG. 7 depicts a block diagram of the salient components of system control center 110, which comprises: i. hazardous material detection station map 701, ii. system processor 702, iii. video switch 703, and iv. video display 704, interconnected as shown. One of the advantages of the illustrative embodiment is that it incorporates mechanisms that seek to thwart false system alarms. One of these mechanisms is based on the understanding that a chemical, biological, radiological, or nuclear weapon attack is more likely to issue when there are alarms from multiple stations that are near each other than when there are alarms from multiple stations that are not near each other (e.g., are randomly distributed around the area that is monitored, etc.). To facilitate this analysis, the illustrative embodiment comprises a map—hazardous material detection station map 701—that associates each hazardous material detection station to its location (e.g., latitude and longitude, etc.). Another of the mechanisms that the illustrative embodiments uses to prevent false system alarms is based on the understanding that alarms from multiple stations are more likely to occur temporally in the same direction as the wind—as the hazardous material is blown downwind and into contact with the various hazardous material detection stations. To facilitate this analysis, hazardous material detection station map 701 also associates each environmental sensor array to its location. In accordance with the illustrative embodiment, hazardous material detection station map 701 is a data structure, such as that depicted in Table 1. TABLE 1 Hazardous Material Detection Station Map 701 Latitude Longitude Hazardous Material Detection 40° 35′ 56.03″ N. 140° 35′ 46.44″ E. Station 411-1 Hazardous Material Detection 40° 34′ 26.83″ N. 140° 36′ 36.02″ E. Station 411-2 . . . . . . . . . Hazardous Material Detection 40° 36′ 36.14″ N. 140° 38′ 56.33″ E. Station 411-11 Environmental Sensor 40° 35′ 56.66″ N. 140° 33′ 14.03″ E. Array 101-12 Environmental Sensor 40° 36′ 49.35″ N. 140° 35′ 06.55″ E. Array 101-13 . . . . . . . . . Environmental Sensor 40° 37′ 35.93″ N. 140° 35′ 52.83″ E. Array 101-17 It will be clear to those skilled in the art how to make hazardous material detection station map 701. System processor 702 receives the telemetry from hazardous material detection alarms 411-1 through 411-11, the telemetry from environmental sensor arrays 101-1 through 101-17, and the location data from hazardous material detection station map 701 and determines whether or not to issue a system alarm. In accordance with the illustrative embodiment, system processor 702 is a general-purpose processor that is programmed to perform the functionality described herein and with respect to FIGS. 8 through 11. When system processor 702 determines that an attack has occurred or is occurring, it issues a system alarm to the personnel who monitor the illustrative embodiment (who are not shown in FIG. 7) and it directs video switch 703 to automatically route the video feed(s) for the area(s) where the attack has occurred or is occurring to video display 704. This enables the personnel who monitor the illustrative embodiment to further verify the attack. For example, if system processor 702 determines that a chemical gas attack is occurring in Times Square, then video of people collapsing and convulsing in Times Square will enable the personnel who monitor the illustrative embodiment to verify that indeed a gas attack has occurred. In contrast, if system processor 702 determines that a chemical gas attack is occurring in Times Square, then video showing people going about their business as usual will suggest to the personnel who monitor the illustrative embodiment that it is a false alarm or that it should be investigated more thoroughly. Video switch 703 is controllable by system processor 702 as it is well known to those skilled in the art, and video display 704 is also well known to those skilled in the art. FIG. 8 depicts a flowchart of the salient tasks associated with the deployment and operation of the illustrative embodiment. At task 801, hazardous material detection station map 701 is built and environmental sensor arrays 101-1 through 101-17, video camera clusters 102-1 through 102-13, and hazardous material detection stations 103-1 through 103-11 are deployed throughout city 100 in accordance with hazardous material detection station map 701. It will be clear to those skilled in the art, after reading this specification, how to perform task 801. At task 802, system processor 702 in system control center 110 continually receives the station alarm status from each of the six station alarms for each of the eleven hazardous material detection stations (i.e., system processor 702 periodically receives the station alarm status for all 11×6=66 station alarms). In the best of cases, system processor 702 does not receive any station alarms. At task 803, system processor 702 in system control center 110 continually receives the environmental telemetry transmitted from each of the eight environmental sensors for each of the sixteen environmental sensor arrays (i.e., system processor 702 periodically receives the environmental data for all 16×8=128 environmental sensors). At task 804 system processor 702 in system control center 110 continually receives the video signals from each of the thirteen video surveillance clusters. In accordance with the illustrative embodiment, tasks 802, 803, and 804 are performed concurrently, but it will be clear to those skilled in the art, after reading this specification, how to make and use alternative embodiments of the present invention in which tasks 802, 803, and 804 are performed in any order. At task 805, system processor 702 in system control center 110 determines whether a system-wide alarm should be issued. In accordance with the illustrative embodiment, system processor 702 determines whether to issue a system-wide alarm based on: i. the number of station alarms that are received, ii. the number of hazardous materials that are detected, ii. the proximity of the station alarms, when there is more than one station alarm, iv. the temporal sequence in which the station alarms are received, when there is more than one station alarm, and v. the environmental conditions (including wind direction). It will be clear to those skilled in the art, however, after reading this specification, how to make and use alternative embodiments of the present invention that omit one or more of these factors. When system processor 702 determines that an alarm should be issued, control passes to task 806; otherwise control returns to task 802. The details of task 805 are described below and with respect to FIG. 9. At task 806, system processor 702 issues a system-wide alarm and directs video switch 703 to direct the video telemetry from areas where the station alarms are coming to video display 704. After task 806 has been performed, control returns to task 802. FIG. 9 depicts a flowchart of the salient tests in task 805 of FIG. 8. It will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that omit one or more of the tests. At test 901, system processor 702 determines whether at least N of M neighboring hazardous material detection stations issued an alarm for a first hazardous material, wherein N and M are positive integers, wherein 2≦N≦M≦K, and wherein at least one of N and M change based on an environmental factor. Test 901 incorporates three different mechanisms for reducing the probability that a false system-wide alarm will be issued. The first mechanism requires that at least N (wherein 2≦N) stations report an alarm for the same hazardous material within an interval of time. This prevents a false alarm from one hazardous material detection station from issuing a false system-wide alarm. If the probability of a station issuing a false alarm is p and the probability of each station issuing a false alarm is independent of another station issuing a false alarm, then the probability that the illustrative embodiment will issue a false system-wide alarm is no higher than pN. The implication is that the probability of issuing a false system-wide alarm is affected by the value of N. High values of N lower the likelihood of a false system-wide alarm, but also increase the likelihood that a real system-wide alarm will not issue. It will be clear to those skilled in the art, after reading this specification, how to select values for N based on the acceptable likelihood of a false system-wide alarm and on the likelihood that a real system-wide alarm will not issue. The second mechanism requires that the N stations reporting an alarm for the same hazardous material within an interval of time be a subset of M neighboring stations (i.e., have some proximity to each other). For the purpose of this specification, M stations are “neighboring stations” if and only if a circle exists that contains all M stations and no other stations. System processor 702 uses Hazardous Material Detection Station Map 701 to determine if a circle exists that contains all M stations and no other stations. The purpose of this mechanism is to issue a system-wide alarm only when the N stations reporting an alarm for the same hazardous material within an interval of time have some proximity to each other. This is based on the assumption that a real attack is more likely to be detected by stations that are near each other than by stations that have no proximity. Small values of M lower the likelihood of a false system-wide alarm, but also increase the likelihood that a real system-wide alarm will not issue. It will be clear to those skilled in the art, after reading this specification, how to select values for M based on the acceptable likelihood of a false system-wide alarm and on the likelihood that a real system-wide alarm will not issue. The third mechanism changes the values of at least one of N and M based on at least one environmental factor (e.g., precipitation, wind speed, the amount of sunlight, etc.) to cause the threshold for a system-wide alarm to be higher when the environmental factor(s) suggest that an attack is less likely. For example, the ratio of N:M will be higher when it is precipitating, when it is not windy, and when it is sunny. It will be clear to those skilled in the art, after reading this specification, how to change the values of N and M based on environmental factors based on the acceptable likelihood of a false system-wide alarm and on the likelihood that a real system-wide alarm will not issue. In some alternative embodiments of the present invention, test 901 determines whether A % of the hazardous material detection stations within B meters issued an alarm for a first hazardous material, wherein A and B are positive real numbers, wherein 0%≦A %≦100%, and wherein at least one of A and B change based on an environmental factor. At test 902, system processor 702 determines whether at least P of V neighboring hazardous material detection stations issued an alarm for the first hazardous material, wherein P and V are positive integers, 2≦P≦V≦K, N≦P and wherein at least one of P and V change based on an environmental factor. The purpose of test 902 is to ensure that a system-wide alarm is only issued when the extent of the stations reporting an alarm expands, as would be expected in a real attack. Test 902 incorporates three different mechanisms for reducing the likelihood that a false system-wide alarm will be issued, and these three mechanisms are analogous to those in test 901. Therefore, it will be clear to those skilled in the art, after reading this specification, how to select values for P and V and how to change them based on environmental factors based on the acceptable likelihood of a false system-wide alarm and on the likelihood that a real system-wide alarm will not issue. In some alternative embodiments of the present invention, test 902 determines whether C % of the hazardous material detection stations within D meters issued an alarm for the first hazardous material, wherein C is a positive real number, wherein 0% ≦C %≦100%, and wherein at least one of C and D change based on an environmental factor. At test 903, system processor 702 determines whether at least R of S neighboring hazardous material detection stations issued an alarm for a second hazardous material, wherein R and S are positive integers, wherein 2≦R≦S≦K, and wherein at least one of R and S change based on an environmental factor. The purpose of test 903 is to ensure that a system-wide alarm is only issued when a second hazardous material is detected in addition to the first hazardous material, as would be expected in some types of real attacks. For example, in a nuclear attack, the detection of alpha particles might be accompanied by the detection of beta particles. There are, of course, other kinds of attacks that involve only one type of hazardous material. In some alternative embodiments of the present invention, test 903 determines whether E % of the hazardous material detection stations within F meters issued an alarm for a second hazardous material, wherein E is a positive real number, wherein 0%≦E %≦100%, and wherein at least one of E and F change based on an environmental factor. Test 903 incorporates three different mechanisms for reducing the likelihood that a false system-wide alarm will be issued, and these three mechanisms are analogous to those in test 901. Therefore, it will be clear to those skilled in the art, after reading this specification, how to select values for R and S and how to change them based on environmental factors based on the acceptable likelihood of a false system-wide alarm and on the likelihood that a real system-wide alarm will not issue. At test 904, system processor 702 determines whether the spread of station alarms is generally consistent with the prevailing wind direction, as would be expected in a real attack as the hazardous material is blown downwind. To do this processor 702 uses it knowledge of the position of the stations reporting alarms, hazardous material detection station map 701, and its knowledge of the prevailing wind direction, which it gleans from the environmental sensor arrays in the vicinity of the stations reporting alarms. It will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that decide whether the spread of station alarms is generally consistent with the prevailing wind direction. FIG. 10 depicts a flowchart of the salient tasks associated with the operation of hazardous material detection processor 402-k. At task 1001, hazardous material detection processor 402-k receives the environmental data from environmental sensor array 101-k. It will be clear to those skilled in the art how to make and use embodiments of the present invention that perform task 1001. At task 1002, hazardous material detection processor 402-k receives the hazardous material measurements from hazardous material sensor array 401-k. It will be clear to those skilled in the art how to make and use embodiments of the present invention that perform task 1002. Furthermore, it will be clear to those skilled in the art, after reading this specification, how to make and use embodiments of the present invention that perform tasks 1001 and 1002, concurrently or in any order. At task 1003, hazardous material detection processor 402-k determines, based on the measurements received in task 1002 and the environmental data received in task 1001, whether the amount of a hazardous material has reached a threshold such that the station's alarm should be issued. When hazardous material detection processor 402-k determines that the alarm should be issued, control passes to task 1004; otherwise control returns to task 1001. Hazardous material detection processor 402-k incorporates a mechanism to reduce the probability that a false station alarm will be issued. In particular, hazardous material detection processor 402-k changes the threshold for each hazardous material based, at least in part, on the environmental data received in task 1001. For example, FIG. 11 depicts the threshold for VX Gas in parts per million (ppm) as a function of both precipitation and whether or not it is sunny. From FIG. 11, it can be seen that the threshold is higher when it is precipitating and sunny than when it is not precipitation or not sunny or neither precipitating nor sunny. At task 1004, hazardous material detection processor 402-k transmits a station alarm to system control center 110, via wireline 412-k. After task 1004, control returns to task 1001 to determine if an alarm for a second hazardous material should be issued and to determine if the amount of the first hazardous material has fallen (or the threshold raised) such that the alarm should be discontinued. It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. For example, in this Specification, numerous specific details are provided in order provide a thorough description and understanding of the illustrative embodiments of the present invention. Those skilled in the art will recognize, however, that the invention can be practiced without one or more of those details, or with other methods, materials, components, etc. Furthermore, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the illustrative embodiments. It is understood that the various embodiments shown in the Figures are illustrative, and are not necessarily drawn to scale. Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that a particular feature, structure, material, or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the present invention, but not necessarily all embodiments. Consequently, the appearances of the phrase “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout the Specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>A chemical, biological, radiological, or nuclear attack on a civilian population is a dreadful event, and the best response requires the earliest possible detection of the attack so that individuals can flee and civil defense authorities can contain its effects. To this end, chemical, biological, radiological, and nuclear weapons detection systems are being deployed in many urban centers that will give civil defense authorities almost instant notification that an attack has occurred.
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<SOH> SUMMARY OF THE INVENTION <EOH>A terrorist seeks to impose his or her will on a government by convincing its citizenry that conciliation—and not confrontation—will make the threat disappear. If the government is able to protect its citizens from violence, the policy of confrontation will be deemed successful and the terrorist's agenda will be thwarted. In contrast, if the terrorist is able to strike wherever and whenever it desires, the policy of confrontation will be deemed unsuccessful and the terrorist's agenda will be promoted by those who favor conciliation. In either case, the government and the terrorist are locked in a struggle to undermine the citizenry's respect and confidence in the other. It warrants repeating that the salient traits that the government and the terrorists vie for are respect and confidence, and, therefore, any factor—however apparently remote—that enhances or detracts either's respect and confidence is important. One way that the government earns and maintains the respect and confidence of the citizenry is by quickly and accurately informing the public when an attack has occurred and by taking the appropriate action. This means that there are two ways in which the government can lose the respect and confidence of the citizenry. First, the government can fail to inform the public when an actual attack has occurred, and second, the government can inform the public that an attack has occurred when in fact there has been so such attack. Therefore, it's important for the government to inform the public of an attack when an attack has in fact occurred, but that it is also important for the government not to issue false alarms. To this end, the respect in the government is best enhanced by a chemical, biological, radiological, and nuclear weapon detection system that both: (1) quickly issues an alarm in the event of a real attack, and (2) accurately withholds false alarms. The illustrative embodiment of the present invention incorporates a mechanism to reduce the probability that a false alarm will be issued. In particular, the mechanism causes an alarm to be triggered when the amount of a hazardous material reaches a threshold, but changes the threshold based, at least in part, on environmental (e.g., meteorological, etc.) characteristics (e.g., whether is it precipitating or not, whether it is sunny or not, etc) that effect the efficacy of a chemical, biological, radiological, or nuclear weapon. For example, it is well understood that a chemical gas attack is likely to be less effective when it is raining than when it is clear because the rain will suppress and dilute the chemical agent. Given that there are environmental factors that make an attack less effective, and given that terrorists are aware of this, the illustrative embodiment is less likely to issue an alarm when the environmental factors suggest that an attack is less effective, and, therefore, less likely. The illustrative embodiment accomplishes this by changing the threshold needed to issue an alarm based on one or more the environmental factors. The illustrative embodiment comprises: a first environmental sensor for monitoring a first environmental characteristic; a first hazardous material sensor for measuring the amount of a first hazardous material; and a first alarm that is issued when the amount of the first hazardous material reaches a first threshold, wherein the first threshold changes and is based on the first environmental characteristic.
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20040630
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20060808
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20060105
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69902.0
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G08B2900
| 0
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TWEEL JR, JOHN ALEXANDER
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CHEMICAL, BIOLOGICAL, RADIOLOGICAL, AND NUCLEAR WEAPON DETECTION SYSTEM WITH ALARM THRESHOLDS BASED ON ENVIRONMENTAL FACTORS
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UNDISCOUNTED
| 0
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ACCEPTED
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G08B
| 2,004
|
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10,882,178
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ACCEPTED
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Holographic human-machine interfaces
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A holographic HMI is described by which data and commands can be entered into computers and other electronic equipment. The holographic HMI involves no tangible physical contact between the human operator and the control elements of the HMIs because the input devices are holographic images of keys or other customarily touch-activated tangible input elements. Operator interaction with those holographic images is detected through electromagnetic means or other means, obviating the need for direct physical contact with any solid input object or surface. Such holographic HMIs comprise a hologram for generating a holographic image of a tangible input object of the tangible control mechanism for the electronic or electro-mechanical device. An illumination device illuminates the hologram to produce the holographic image. An actuation detection device detects the selection by the operator of a holographic image, generated by the hologram, of the tangible input object, and a signal generator receives the detection of the actuation detection device and provides an input signal to the electronic or electro-mechanical device thereby to produce the response. The hologram is affixed to a transparent or translucent material.
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1. An apparatus allowing an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible control mechanism having one or more customarily touch-activated tangible input objects, physical contact with which produces a response by the electronic or electro-mechanical device, said apparatus allowing such control without the operator physically touching any solid object and comprising: hologram means for generating a holographic image of a tangible input object of the tangible control mechanism for the electronic or electro mechanical device; illumination means for illuminating said hologram means to produce the holographic image; actuation detection means for detecting selection by the operator of the holographic image, generated by said hologram means, of the tangible input object; and signal generation means for receiving the detection of said actuation detection means and providing an input signal to the electronic or electro mechanical device thereby to produce the response, wherein said hologram means is affixed to at least one of a transparent material and a translucent material. 2. An apparatus according to claim 1, wherein said at least one of said transparent material and said translucent material is selected from glass, acrylic, and plastic. 3. An apparatus according to claim 1, wherein the actuation generation means comprises: emission/detection means for producing and receiving electromagnetic radiation, positioned on a side of said hologram means opposite the operator, wherein said emission/detection means is positioned to transmit and receive electromagnetic radiation toward the holographic image of the tangible input object and through said material to which said hologram means is affixed, and said emission/detection means determines the selection by the operator of the holographic image of the tangible input object through the material. 4. An apparatus according to claim 1, further comprising at least one mirror so as to alter said illumination means light path to position one or more holographic image on an edge of a screen that is employed to present information to the operator. 5. An apparatus for allowing an operator to control a plurality of electronic or electro mechanical devices of the type conventionally controlled by a separate tangible control mechanism having a plurality of customarily touch-activated tangible input objects, physical contact with which produces a response by at least one of the electronic or electro mechanical devices, the apparatus allowing such control without the operator physically touching any solid object and comprising: a hologram unit adapted to generate a plurality of holographic images each of one of the tangible input objects of the tangible control mechanism for the plurality of said electronic or electro mechanical devices; illumination means for illuminating said hologram unit to produce the plurality of holographic images; an actuation detector unit adapted to detect selection by the operator of each of the plurality of holographic images of the tangible input devices; and a signal generator adapted to receive the detection of said actuation detector unit and provide an input signal to the devices thereby producing the response, wherein said actuation detector and said signal generator are configured to independently produce a response by each electronic or electro mechanical device upon detection of selection of each independent one of said holographic images. 6. A control arrangement apparatus for allowing an operator to control an electronic or electro mechanical device of the type conventionally controlled by a tangible control mechanism having a customarily touch-activated tangible input object physical contact with which produces a response by the device, said control arrangement allowing such control without an operator physically touching any solid object and comprising: a composite hologram for generating a holographic image of a plurality of tangible input objects of the tangible control mechanism for the device, with the generated holographic image for producing a response by the device corresponding to that produced conventionally by the plurality of tangible input objects of the tangible control mechanism, said composite hologram comprising a plurality of holograms positioned side-by-side along one axis such that each of the holographic images produced thereby represents a different portion of the tangible input objects, such that each of the holographic images can be separately viewed from a different angle relative to said one axis; an actuation detector for detecting selection by the operator of the holographic image of each of the tangible input devices; and a signal generator for receiving the detection of said actuation detector and providing an input signal to the device thereby to produce the response. 7. A control arrangement apparatus according to claim 6, wherein said composite hologram consists of a plurality of holograms positioned side-by-side along a second axis generally perpendicular to said one axis such that each of the holographic images represents a different portion of the tangible input objects, such that each of the holographic images presented by said composite hologram can be separately viewed from a different angle relative to said second axis. 8. An apparatus as in claim 1, 5, or 6, wherein said hologram means generates a plurality of holographic images, each of one of a plurality of tangible input objects, and wherein said actuation detection means is capable of detecting which of said plurality of holographic images is selected by the operator. 9. An apparatus as in claim 1, 5, or 6, further comprising at least one mirror interposed between said hologram means and said illumination means so as to shorten the physical distance between said hologram means and said illumination means and nevertheless produce the holographic image. 10. An apparatus as in claim 1, 5, or 6, wherein said hologram means includes a lens with convergent properties. 11. An apparatus as in claim 1, 5, or 6, further comprising at least one lens interposed between said hologram means and said illumination means so as to shorten the physical distance between said hologram means and said illumination means and nevertheless produce the holographic image. 12. An apparatus as in claim 1, 5, or 6, wherein said signal generation means also generates at least one of an audible signal and a visible signal to indicate to the operator that the actuation detection means has detected selection of the holographic image by the operator. 13. An apparatus as in claim 1, 5, or 6, wherein said illumination means comprises a reconstructing light source located at the edge of the material to which said hologram means is affixed. 14. An apparatus allowing an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible mechanism having one or more customarily touch-activated tangible input objects, physical contact with which produces a response by the electronic or electro-mechanical device, said apparatus allowing such control without the operator physically touching any solid object and comprising: an actuator image generating unit adapted to generate at least one of a plurality of three-dimensional images of the one or more tangible input objects of the tangible control mechanism for the electronic or electro mechanical device; an actuator detecting unit adapted to determine the selection by the operator of the at least one of the plurality of three-dimensional images, generated by said actuator image generating unit, of the tangible input objects; and a signal-generating unit adapted to receive the determination of said actuation detection means and to provide an input signal to the electronic or electro mechanical device, wherein said actuation detecting unit and signal generating unit are adapted to produce a response upon detection of selection of each three-dimensional image, and wherein said actuator image generating unit is contained in an electronic or electro mechanical device capable of projecting a three-dimensional image within physical proximity of the operator. 15. A method of allowing an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible control mechanism having one or more customarily touch-activated tangible input objects, physical contact with which produces a response by the electronic or electro-mechanical device, said method allowing such control without the operator physically touching any solid object and comprising: an actuator image generating step of generating at least one of a plurality of three-dimensional images of the one or more tangible input objects of the tangible control mechanism for the electronic or electro mechanical device; an actuation detecting step of determining the selection by the operator of the at least one of the plurality of three-dimensional images, generated in said actuator image generating step, of the tangible input objects; and a signal-generating step of receiving the determination from said actuation detection step and providing an input signal to the electronic or electro mechanical device, wherein said actuation detecting step and signal generating step produce a response upon detection of selection of each three-dimensional image, and wherein said actuator image generating step is capable of projecting a three-dimensional image within physical proximity of the operator.
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This application claims the benefit of U.S. Provisional Application No. 60/484,838, filed Jul. 3, 2003, the disclosure of which is hereby incorporated by reference in its entirety, as if fully set forth herein. BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to holographic human-machine interfaces (“HMIs”) between humans and electronic or electro-mechanical devices. 2. Description of Related Art There are many methods and devices available for entering data and commands into computers and other electronic equipment, such devices including, for example, keyboards, key pads, light pens, mice, pushbuttons, touch screens and trackballs. All of these input devices share a common feature: they require tangible physical contact by a user of the computer or electronic equipment. However, holographic HMIs involve no tangible physical contact between the human operator and the control elements of the HMIs because the input devices are holographic images of keys or other customarily touch-activated tangible input elements. Operator interaction with those holographic images is detected through electromagnetic means or other means, obviating the need for direct physical contact with any solid input object or surface. Holographic HMIs between humans and electronic or electro-mechanical equipment are known in the art. Most notably, a “Holographic Control Arrangement” is described in U.K. Patent No. 2292711 (McPheters) and in U.S. Pat. No. 6,377,238 (McPheters), which are incorporated herein by reference. Known holographic HMI systems may be characterized by the holographic HMI devices being relatively large and bulky, and they may consume relatively large amounts of power, making them impractical for some uses. A problem may also occur with known holographic HMIs, when they are intended to replace touch screens or touch pads presenting multiple screens of information to the operator, because their holographic images cannot be smoothly integrated with input or output information available to the human operator on information presentation equipment of the electronic or electro-mechanical device being controlled. In addition, a problem may occur when more than one piece of electronic or electro-mechanical equipment is controlled by holographic HMIs, requiring multiple holographic images. In such situations, an operator is easily distracted by the multiple images. Another problem posed by present holographic HMIs is that, as compared with conventional interfaces, the operator of a holographic HMI receives no tactile feedback when interacting with a holographic HMI, which may cause the operator of the holographic HMI to lose track of the commands or information being entered into the electronic or electro-mechanical device. Further, a problem may occur when the footprint of known holographic HMIs is not smaller than the physical dimensions of the conventional human-machine interfaces of the electronic or electro-mechanical device(s) being controlled. SUMMARY OF INVENTION The present invention is made in consideration of the above situations, and has the object to provide an apparatus for realizing the reduction of the power consumption, size and weight of conventional holographic HMIs. Further, the smoothness with which they can be integrated with information presentation features of the electronic or electro-mechanical device being controlled can be enhanced and the convenience of their human operators can be facilitated using the various methods of the present invention. In order to attain the above objects, in accordance with the present invention, an apparatus is provided to allow an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible control mechanism having one or more customarily touch-activated tangible input objects, where physical contact with the device produces a response by the electronic or electro-mechanical device. The apparatus allows such control without the operator physically touching any solid object. The apparatus comprises hologram means for generating at least one of a plurality of holographic images of the one or more tangible input objects of the tangible control mechanism for the electronic or electro-mechanical device; illumination means for illuminating the hologram means to produce the at least one of a plurality of holographic images; actuation detection means for determining the selection by the operator of the at least one of a plurality of holographic images, generated by the hologram means, of the tangible input objects; and signal generation means for receiving the determination of the actuation detection means and providing an input signal to the electronic or electro-mechanical device thereby to produce the response, where the hologram means is affixed to a transparent or translucent material of the type including, but not limited to, glass, acrylic or plastic. According to another aspect of the present invention, an apparatus is provided for allowing an operator to control more than one electronic or electro-mechanical device of the type conventionally controlled by a separate tangible control mechanism having at least one of a plurality of customarily touch-activated tangible input objects, where physical contact produces a response by the more than one electronic or electro mechanical devices. The apparatus allows such control without the operator physically touching any solid object. The apparatus comprises a hologram unit adapted to generate at least one of a plurality of holographic images of the one or more tangible input objects of the tangible control mechanism for the one electronic or electro mechanical devices; illumination means for illuminating the hologram unit to produce each holographic image; an actuation detector unit adapted to determine selection by the operator of each holographic image of the tangible input devices; a signal generator adapted to receive the determination of the actuation detector unit and provide an input signal to the devices thereby producing the response, where each of the generated holographic images is capable of independently producing a response by each electronic or electro mechanical device corresponding to that produced conventionally by the one or more tangible input objects of the tangible control mechanism of each such electronic or electro mechanical device. According to another aspect of the present invention, a control arrangement apparatus for allowing an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible control mechanism having at least one of a plurality of customarily touch-activated tangible input objects, where physical contact with which produces a response by the device is provided. The control arrangement allows such control without an operator physically touching any solid object. The control arrangement comprises a composite hologram for generating a holographic image of at least one of a plurality of tangible input objects of the tangible control mechanism for the device, with the generated holographic image, for producing a response by the device, corresponding to that produced conventionally by each of tangible input objects of the tangible control mechanism. The composite hologram consists of a plurality of narrow holograms positioned side-by-side along a horizontal axis such that each of the holographic images presents a different thin vertical slice of what would otherwise be images of the tangible input objects, such that each of the narrow holographic images presented by the composite hologram can be separately viewed from a slightly different angle in the horizontal plane, either by the operator moving his or her head from right to left or left to right in the horizontal plane, by the operator slightly turning said composite hologram slightly from right to left or from left to right in the horizontal plane or by the hologram's being illuminated from different angles. An actuation detector for determining selection by the operator of the holographic image of the tangible input devices, and a signal generator for receiving the determination of the actuation detector and providing an input signal to the device thereby to produce the response. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is schematic functional representation of an HMI according to the principles of the invention, the sensor(s) of which, used to detect the operator's interaction with the holographic images, are positioned behind the hologram in relation to the operator. FIG. 2 is a schematic functional representation of an HMI according to the principles of the invention, the sensors of which, used to detect the operator's interaction, are positioned below, above, or to the side of an edge of a screen of the device employed to present input or output information to the operator of the electronic or electro mechanical device being controlled and the holographic images function as soft keys, determined by corresponding icons or other symbols on the screen. FIG. 3 is a schematic functional representation of an HMI according to the principles of the invention, where holographic images of more than one electronic or electro mechanical device interfaces are projected in one convenient location. FIG. 4 is a schematic functional representation of one embodiment of an HMI according to the principles of the invention, where the physical separation between its hologram and reconstructing light source is reduced using one or more mirrors. FIG. 5 is a schematic functional representation of one embodiment of an HMI according to the principles of the invention where the physical separation between its hologram and its reconstructing light is reduced using one or more lenses. FIG. 6 is a block diagram of one embodiment of an HMI according to the principles of the invention, where an audio or visible response is provided to the operator upon interaction with the HMI, in lieu of a tactile response. FIG. 7 is a schematic functional representation of one embodiment of an HMI according to the principles of the invention, where one or more narrow holograms are recorded in such as way as to allow the operator to see, and interact with, its reconstructed images from different angles along the horizontal or vertical axes. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIRST EMBODIMENT—SENSOR POSITIONING The first embodiment of the present invention provides a means for reducing the size and weight of holographic HMIs by positioning detecting sensors behind the hologram in relation to the operator, so as to permit those sensors to “look through” the medium upon which the hologram is mounted. This arrangement offers a desirable alternative to positioning of wave source sensors alongside the hologram or on the same side of the hologram as the operator because required hardware can be more compact, reducing the size and weight of the holographic HMI. Certain types of wave source sensors suitable for use in the construction of holographic HMIs can “look through” certain types of materials on which holograms can be affixed, embossed or mounted. The types of materials on which holograms can be affixed, embossed or mounted include, but are not limited to, acrylic, glass and plastic, of varying thicknesses. Types of sensors that can “look through” those materials include, but are not limited to, those emitting/detecting certain wave lengths of infrared emissions, for example, a sensor emitting infrared light having a wavelength of approximately 880 nanometers. Traditional reflection and transmission holograms are well known in the art and can be used in holographic HMIs. The former involves the use of a reconstructing light source positioned on the same side of the hologram as the HMI's operator while the latter involves a reconstructing light source positioned behind the hologram in relation to the operator either directly or through the use of reflective materials. A developing technology, the edge-lit hologram, offers potentially significant advantages in reducing the size and weight of holographic HMIs, as described below. In each case, it is well known in the art that holographic images are translucent, with the result that they can be projected in front of other objects without obscuring them. While edge-lit holograms are known in the art (See S. A. Benton, S. M. Birner and A. Shirakura, “Edge-Lit Rainbow Holograms” in SPIE Proc. Vol. 1212, Practical Holography IV (Soc. Photo-Opt. Instr. Engrs., Bellingham, Wash. 1990)), their use in connection with holographic HMIs is believed to be not known in the art. The images of an edge-lit hologram are reconstructed by using a light source positioned at an edge of a holographic HMI hologram, to illuminate that edge, thereby reconstructing that hologram's images at a distance from the material containing the edge-lit hologram, and obviating the physical separation between reconstructing light source and hologram that accompanies both reflection and transmission holograms. Employing an edge-lit hologram as a holographic HMI's reconstructing light source eliminates the need for significant distance between an HMI's hologram and its reconstructing light source, which permits the use of smaller and lighter hardware to construct the HMI. FIG. 1 is a schematic functional representation of a HMI according to the principle of this invention in which the sensor(s) detecting an operator's interaction with holographic images of what would otherwise be keys or other customarily touch-activated tangible input devices of electronic or electro mechanical devices are positioned behind the hologram in relation to the operator. In FIG. 1, in the case where the hologram 421 is a transmission hologram, the reconstructing light source 28 is located behind the hologram 421 to thereby illuminate the hologram. Accordingly, a holographic image 270 is projected into the air in front of the operator. In the case where the hologram 421 is a reflection hologram, it is illuminated by a reconstructing light source 28′, located in front of hologram 421. Again, a holographic image 270 is projected into the air in front of the operator. In the case where the hologram 421 is an edge-lit hologram, it is illuminated by a reconstructing light source 28″ at its edge, and a holographic image 270 is projected into the air in front of the operator. Techniques for generating holographic images from transmission, reflection and edge-lit holograms are well known in the art. Actuation of the device may be detected by wave source emitter/detector 350 that emits wave 360, aimed at hologram 421. Because of this oblique angle, the wave as well as its reflection, passes through the material (not shown) on which the hologram is affixed, embossed or mounted. When the presence of a physical object (such as the operator's FIG. 11, indicated in FIG. 1 at 11) enters the apparent position of the holographic image 270, wave 360 is reflected to emitter/detector 350 as wave 370. Because of the transmissible nature of the composition of the material on which hologram 421 is affixed, embossed or mounted, the reflected wave is detected by emitter/detector 350, despite the presence of the material on which hologram 421 is mounted. The reflected wave causes emitter/detector 350 to transmit the operator's selection of the holographic image to the HMI's electronic or electro mechanical device in a way and with apparatus as described, for example, in U.S. Pat. No. 6,377,238. SECOND EMBODIMENT—SCREEN-EDGE HMIs The second embodiment of the present invention provides a means for positioning the hologram(s) so that their reconstructed holographic images of keys or other customarily touch-activated tangible input devices appear below, above, or on either side of the screen employed to present input or output information to an operator, with respect to the electronic or electro mechanical device(s) being actuated or controlled. 30In FIG. 2, information presentation device 94 (or other electronic presentation of information) concerning the electronic or electro mechanical device is actuated or controlled by holographic HMIs. Icons (or other symbols) 44 appearing on the information presentation device 94 indicate possible choices or selections for the operator of the holographic HMI's electronic or electro mechanical device. Holographic images 270 corresponding to icons (or other symbols) 44 are positioned below, above, or on either side of information presentation device 94 in order to facilitate the operator's entry of commands or information into the holographic HMI's electronic or electro mechanical device, acting as soft keys, the function of which is determined by the assigned functions of the icons (or other symbols). Holographic images 270 are reconstructed from holograms 421 by a reconstructing light source 28 located behind holograms 421, if holograms 421 are transmission holograms, by a reconstructing light source 28′ located in front of holograms 421, if holograms 421 are reflection holograms, or by reconstructing light sources 28″ if holograms 421 are edge-lit holograms. As shown in FIG. 2, sensor 350 is positioned so as to detect the intrusion of a finger or other physical object into the plane of each of holographic images 270 in the present embodiment. Shown in FIG. 4 is a schematic functional representation of one embodiment of an HMI according to the principles of the present embodiment where one or more mirrors 52 are used to alter the path of its reconstructing light source 28 in order to more conveniently position its hardware, where holograms 421 are transmission holograms, and their holographic images 270 are reconstructed by light source 28. In this embodiment of a screen-edge holographic HMI, the path of the reconstructing light source is “wrapped around” the hardware of the holographic HMI (not shown), providing a means to construct a compact holographic HMI using well known methods of reconstructing the images of a transmission hologram, so as to conveniently present holographic images according to the second embodiment of the present in a space-efficient manner. By positioning a holographic HMI's images according to the principles of this embodiment, the electronic or electro mechanical device is capable of presenting multiple “screens” of information to the operator, selected by interacting with one or more of those holographic images appearing below, above or on either side of the screen of the device itself. The operator then makes his/her selections on each individual “screen” of information presentation device 94 by interacting with the different holographic images, in conjunction with corresponding characters, icons, letters, prompts or other symbols appearing on each individual “screen” appearing on information presentation device 94 which are proximate to the holographic images intended to enter data with respect to those characters, icons, letters, prompts or other symbols. Holographic HMIs constructed according to the principles of this embodiment offer clearer information presentation on the information presentation device displaying information to the operator, as compared to conventional touch screens or touch pads. THIRD EMBODIMENT—HMIs FOR MULTIPLE DEVICES The third embodiment of the present invention provides a means for improving holographic HMIs intended for use in places or situations where two or more electronic or electro mechanical devices are to be actuated or controlled by a small number of people, such as vehicle or aircraft cockpits or industrial or military control facilities. A single hologram recorded according to methods known to artisans is positioned so as to project images of keys or other customarily touch-activated tangible input devices of two or more electronic or electro mechanical devices at a single location, convenient to the operator(s). This arrangement enhances operator convenience while limiting operator distraction from principal tasks by reducing the operator's need to look away from those tasks in order to interact with electronic or electro mechanical devices. In one example of this embodiment, multiple electronic devices, such as those installed in an automobile cockpit, for example, cellular telephone, radio, air conditioning unit, global position equipment and the like, are actuated and controlled by interacting with a single holographic HMI projected from a hologram recorded according to principles known in the art, presenting translucent holographic images of what would otherwise be the keys or buttons of those devices to the operator, at a location convenient to the operator(s), as shown in FIG. 3. Because holographic images are translucent, they can be projected in front of the operator, for example, in an automobile driver's field of vision, without limiting the driver's view of the road ahead, in a pilot's field of vision, without distracting the pilot from what is going on outside the aircraft, or in front of equipment or gages in an industrial or military control facility, without limiting the operator's attention to that other equipment or gages. In FIG. 3, holographic images 270 are reconstructed from hologram 421 by light source 28 located behind hologram 421, if hologram 421 is a transmission hologram, by light source 28′ located in front of hologram 421, if hologram 421 is a reflection hologram, or by light source 28″, if hologram 421 is an edge-lit hologram. In FIG. 3, sensor 350 detects the entry of a finger or other object into one or more of the holographic image 270. FOURTH EMBODIMENT—RECONSTRUCTING LIGHT SOURCE ECONOMY The fourth embodiment of the present invention provides a means for improving holographic HMIs employing transmission holograms by reducing their size and weight through compressing the distance between their reconstructing light sources and their holograms through recording them using a converging reference beam or by altering the direction of, or focusing or spreading, the light source employed in reconstructing their holographic images through the use of mirrors or lenses. In this embodiment, using a converging reference beam in a known manner to record a transmission hologram results in a short light path between the hologram and its reconstructing light source. In effect, building the convergent properties of a lens into the hologram itself, saves size, space and weight in the resulting HMI and also reduces, if not eliminates, the need for intermediate mirrors or lenses. Mirrors can also be employed to shorten the physical separation between the reconstructing light source of the holographic HMI and the hologram containing an image of keys or other customarily touch-activated tangible input devices of the electronic or electro mechanical devices to be actuated or controlled. In addition, lenses can be used to shorten the physical separation between the reconstructing light source of the holographic HMI and the hologram, as well as focus that emission of the reconstructing light sources, achieving greater clarity of the resulting holographic images. As is known in the art, the distance at which the reconstructing light source of the holographic HMI must be positioned from its transmission hologram in order to achieve optimum image resolution depends upon the angle of the convergence or divergence of the illuminating beam that is prescribed by the recording of the hologram itself. Using one or more mirrors, the total light path needed to reconstruct the holographic images of an HMI can be compressed into a smaller physical space, as shown in FIG. 4. It is also known that analogous effects can be achieved by altering that angle of convergence or divergence through either positioning a lens between light source and film while recording the hologram or by inserting one or more lenses between the reconstructing light beam and the hologram, as shown in FIG. 5. In FIG. 4, mirrors 52 beneath transmission hologram 421 reflect light from reconstructing light source 28 to the hologram. Holographic images 270 are then reconstructed in the space above transmission hologram 421. A similar effect can be achieved by focusing the reconstructing light beam through the use of one or more lenses, as shown in FIG. 5. In FIG. 5, light from reconstructing light source 28 is converged or diverged by passing through lenses 56 before striking transmission hologram 421. Holographic images 270 are reconstructed in the space above transmission hologram 421. A holographic HMI constructed according to the principles of this embodiment can be smaller and more compact owing to the reduced distance between its reconstructing light source and the transmission hologram itself. FIFTH EMBODIMENT—SUBSTITUTE FOR TACTILE FEEDBACK The fifth embodiment of the present invention provides an audible or visible response to the operator of a holographic HMI in the form of an electronic or other tone or a visual signal appearing on the information presentation device, such as a computer screen, to indicate the operator's selection of one or more holographic images of what would otherwise be keys or other customarily touch-activated tangible input devices of the electronic or electro mechanical device being actuated or controlled. This improvement is advantageous because, unlike conventional HMIs, where an operator physically interacts with a key or other customarily touch-activated tangible device and receives a tactile response from touching the HMI, the operator of a holographic HMI receives no tactile feedback upon making a selection using the holographic HMI, since there is nothing to actually touch in interacting with a holographic HMI. Operator accuracy, comfort and speed are, therefore, facilitated by receiving audible or visible evidence of the entry of a command or selection into a holographic HMI according to the principles of this invention, as a substitute for the tactile feedback that an operator interacting with keys or other customarily touch-activated tangible input devices of the electronic or electro mechanical device being actuated or controlled would expect to feel. In a known manner, it is determined which electronic tones or visible signals can be produced by an electronic or electro mechanical device to be controlled by a holographic HMI and which commands to the software of that device must be supplied to that device in order to cause that device to emit one or more of those electronic tones or visible signals, in a manner that its operator can see or hear. In a manner known to artisans, the holographic HMI's software is programmed so as to cause the HMI, upon the operator's interacting with the holographic images of a holographic HMI constructed according to the principles of this embodiment, to transmit one or more commands, selected in order to elicit the desired electronic tone(s) or visible signal(s), to the internal circuitry of the electronic or electro-mechanical device being controlled, which causes the device's hardware to emit the desired electronic tone(s) or display the desired visible signal, clearly indicating to the operator(s) which command or selection has been entered into the electronic or electro mechanical device. FIG. 6 is a block diagram of circuitry according to the present invention that can be used to produce an audible feedback. In FIG. 6, field terminations 1 connect a power supply 2 to external power sources for an HMI according to the principles of this invention and connect output circuitry 3, which may be relays or solid state circuits, to the electronic or electro mechanical device that HMI is intended to actuate or control. In FIG. 6, power supply 2 supplies power to output circuitry 3, detection wave source 14, image light source 28, microprocessor control 4, detection circuitry 11 and audio annunciator 37. Also in FIG. 6, image light source 28, which is controlled by microprocessor control 4, reconstructs the images of hologram 421, in conjunction with image generation optics 52, which may be mirrors or lenses according to the principles of this invention. As also shown in FIG. 6, detection optics 350, which may be contained in the same hardware, include the detection light source 14 and detection circuitry 11, determine when a finger or other object has interacted with those holographic images and signals that event to output circuitry 3 via microprocessor control 4, causing that signal to be transmitted to the electronic or electro mechanical device that HMI is intended to actuate or control as well as to audio annunciator 37. The annunciator 37, in turn, provides an audible indication that the interaction in question has been detected by that HMI. SIXTH EMBODIMENT—MULTIPLE HOLOGRAPHIC IMAGES The sixth embodiment of the present invention provides a means for improving holographic HMIs such that their holographic images of what would otherwise be keys or other customarily touch-activated tangible input devices of the electronic or electro-mechanical devices being actuated or controlled are larger than the physical footprint of the electronic or electro mechanical devices they are intended to actuate or control. The improved holographic HMI is therefore, larger and more convenient to use than the small tactile keyboards, keypads or touch screens found in conventional electronic or electro mechanical devices. This is accomplished by recording images of what would otherwise be keys or other customarily touch-activated tangible input devices in one or more thin holograms so that their reconstructed images are visible to the operator(s) at slightly different angles across the horizontal or vertical axes, allowing the operator to input information with respect to each of those holographic images. The present embodiment is intended to provide operators with holographic HMIs of a comfortable size for normal fingers, not limited by the size of the electronic or electro mechanical devices employing them. In one example of the present embodiment, shown in FIG. 7, one or more narrow holograms 421 are positioned so that their reconstructing light sources cause each of their holographic images to be viewable by the HMI's operator from a slightly different angle across the horizontal or vertical axes. In FIG. 7, holographic images 270 are reconstructed from holograms 421 by light source 28 located behind holograms 421, if holograms 421 are a transmission holograms, by light source 28′ located in front of holograms 421, if holograms 421 are reflection holograms or by light source 28″, if holograms 421 are edge-lit holograms. As is known, laser-viewable holograms are suitable for recording and reconstructing images of holograms intended to be viewable at different angles across both horizontal and vertical axes because of their favorable parallax qualities, for use in the manner contemplated by the present embodiment. Each of the holographic images presented by the holograms contemplated by the present embodiment can be viewed from a slightly different angle, either by the operator moving his or her head slightly to the right or left or up or down, by the operator slightly turning the holographic HMI slightly from right to left or from left to right, or up or down, or by illuminating those holograms with different light sources from different angles, or by the light source moving so as to reconstruct the images of the hologram(s) from different angles. As shown in FIG. 7, sensor 350 is positioned so as to detect the intrusion of a finger or other physical object into the plane of each of holographic images 270 in the present embodiment, at the angle at which those images appear in relation to the HMI. Using known techniques, the holographic HMI transmits the command or information represented by the holographic image selected by the operator(s) to the HMI's electronic or electro mechanical device. The present embodiment is an improvement with respect to the size of the HMI's physical structure, and, therefore, improves its convenience of use and weight. In the interest of completeness, specifications for holographic HMIs as presently contemplated, are attached as Appendix A and are incorporated herein by reference in their entirety. While the present invention has been disclosed with respect to what are presently considered to be the preferred embodiments, the invention is not limited to those embodiments. Rather, the present invention covers various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of Invention The present invention relates to holographic human-machine interfaces (“HMIs”) between humans and electronic or electro-mechanical devices. 2. Description of Related Art There are many methods and devices available for entering data and commands into computers and other electronic equipment, such devices including, for example, keyboards, key pads, light pens, mice, pushbuttons, touch screens and trackballs. All of these input devices share a common feature: they require tangible physical contact by a user of the computer or electronic equipment. However, holographic HMIs involve no tangible physical contact between the human operator and the control elements of the HMIs because the input devices are holographic images of keys or other customarily touch-activated tangible input elements. Operator interaction with those holographic images is detected through electromagnetic means or other means, obviating the need for direct physical contact with any solid input object or surface. Holographic HMIs between humans and electronic or electro-mechanical equipment are known in the art. Most notably, a “Holographic Control Arrangement” is described in U.K. Patent No. 2292711 (McPheters) and in U.S. Pat. No. 6,377,238 (McPheters), which are incorporated herein by reference. Known holographic HMI systems may be characterized by the holographic HMI devices being relatively large and bulky, and they may consume relatively large amounts of power, making them impractical for some uses. A problem may also occur with known holographic HMIs, when they are intended to replace touch screens or touch pads presenting multiple screens of information to the operator, because their holographic images cannot be smoothly integrated with input or output information available to the human operator on information presentation equipment of the electronic or electro-mechanical device being controlled. In addition, a problem may occur when more than one piece of electronic or electro-mechanical equipment is controlled by holographic HMIs, requiring multiple holographic images. In such situations, an operator is easily distracted by the multiple images. Another problem posed by present holographic HMIs is that, as compared with conventional interfaces, the operator of a holographic HMI receives no tactile feedback when interacting with a holographic HMI, which may cause the operator of the holographic HMI to lose track of the commands or information being entered into the electronic or electro-mechanical device. Further, a problem may occur when the footprint of known holographic HMIs is not smaller than the physical dimensions of the conventional human-machine interfaces of the electronic or electro-mechanical device(s) being controlled.
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<SOH> SUMMARY OF INVENTION <EOH>The present invention is made in consideration of the above situations, and has the object to provide an apparatus for realizing the reduction of the power consumption, size and weight of conventional holographic HMIs. Further, the smoothness with which they can be integrated with information presentation features of the electronic or electro-mechanical device being controlled can be enhanced and the convenience of their human operators can be facilitated using the various methods of the present invention. In order to attain the above objects, in accordance with the present invention, an apparatus is provided to allow an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible control mechanism having one or more customarily touch-activated tangible input objects, where physical contact with the device produces a response by the electronic or electro-mechanical device. The apparatus allows such control without the operator physically touching any solid object. The apparatus comprises hologram means for generating at least one of a plurality of holographic images of the one or more tangible input objects of the tangible control mechanism for the electronic or electro-mechanical device; illumination means for illuminating the hologram means to produce the at least one of a plurality of holographic images; actuation detection means for determining the selection by the operator of the at least one of a plurality of holographic images, generated by the hologram means, of the tangible input objects; and signal generation means for receiving the determination of the actuation detection means and providing an input signal to the electronic or electro-mechanical device thereby to produce the response, where the hologram means is affixed to a transparent or translucent material of the type including, but not limited to, glass, acrylic or plastic. According to another aspect of the present invention, an apparatus is provided for allowing an operator to control more than one electronic or electro-mechanical device of the type conventionally controlled by a separate tangible control mechanism having at least one of a plurality of customarily touch-activated tangible input objects, where physical contact produces a response by the more than one electronic or electro mechanical devices. The apparatus allows such control without the operator physically touching any solid object. The apparatus comprises a hologram unit adapted to generate at least one of a plurality of holographic images of the one or more tangible input objects of the tangible control mechanism for the one electronic or electro mechanical devices; illumination means for illuminating the hologram unit to produce each holographic image; an actuation detector unit adapted to determine selection by the operator of each holographic image of the tangible input devices; a signal generator adapted to receive the determination of the actuation detector unit and provide an input signal to the devices thereby producing the response, where each of the generated holographic images is capable of independently producing a response by each electronic or electro mechanical device corresponding to that produced conventionally by the one or more tangible input objects of the tangible control mechanism of each such electronic or electro mechanical device. According to another aspect of the present invention, a control arrangement apparatus for allowing an operator to control an electronic or electro-mechanical device of the type conventionally controlled by a tangible control mechanism having at least one of a plurality of customarily touch-activated tangible input objects, where physical contact with which produces a response by the device is provided. The control arrangement allows such control without an operator physically touching any solid object. The control arrangement comprises a composite hologram for generating a holographic image of at least one of a plurality of tangible input objects of the tangible control mechanism for the device, with the generated holographic image, for producing a response by the device, corresponding to that produced conventionally by each of tangible input objects of the tangible control mechanism. The composite hologram consists of a plurality of narrow holograms positioned side-by-side along a horizontal axis such that each of the holographic images presents a different thin vertical slice of what would otherwise be images of the tangible input objects, such that each of the narrow holographic images presented by the composite hologram can be separately viewed from a slightly different angle in the horizontal plane, either by the operator moving his or her head from right to left or left to right in the horizontal plane, by the operator slightly turning said composite hologram slightly from right to left or from left to right in the horizontal plane or by the hologram's being illuminated from different angles. An actuation detector for determining selection by the operator of the holographic image of the tangible input devices, and a signal generator for receiving the determination of the actuation detector and providing an input signal to the device thereby to produce the response.
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20040702
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20060530
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20050106
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70739.0
| 1
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BOUTSIKARIS, LEONIDAS
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HOLOGRAPHIC HUMAN-MACHINE INTERFACES
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SMALL
| 0
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ACCEPTED
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10,882,206
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ACCEPTED
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Locking the cowl doors of a turbojet
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Turbojet cowl doors have bottom longitudinal edges fitted with hooking means and with locking means which comprise catches fixed on a rotary drive shaft carried by one of the doors and which co-operate with hooking members hinged about an axis on the other one of the doors. The invention relates to apparatus for locking the cowl doors of a turbojet.
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1. Turbojet cowl doors, each door having a top longitudinal edge hinged about a longitudinal axis and a bottom longitudinal edge for fastening by means of locking apparatus to a bottom longitudinal edge of the other door, the apparatus comprising locking members mounted on the bottom longitudinal edge of a first door and co-operating with hooking members mounted on the bottom longitudinal edge of a second door, wherein the locking members are catches each of which is fixed to a rotary drive shaft parallel to the hinge axis of the first door and is movable between a locking angular position and an unlocking angular position, and wherein each hooking member is mounted on the bottom longitudinal edge of the second door to pivot about an axis parallel to the hinge axis of the second door and comprises means for hooking onto a corresponding catch in order to be moved by said catch between a locking angular position and an unlocking angular position. 2. Cowl doors according to claim 1, wherein the catches are carried on a common rotary drive shaft and are movable simultaneously between their locking angular positions and their unlocking angular positions. 3. Cowl doors according to claim 1, wherein the hooking members are independent from one another, each being associated with a return spring urging it towards the unlocking position. 4. Cowl doors according to claim 1, wherein the hooking members project outside the second door when in their unlocking position. 5. Cowl doors according to claim 1, wherein the hooking members are in alignment with the longitudinal edges of the doors when in their locking position. 6. Cowl doors according to claim 1, wherein each hooking member is formed by a tab which is pivotally mounted at one end on the above-mentioned hinge axis and which includes at its opposite end a U-shaped notch whose opening faces towards the hinge axis and is designed to receive a portion of the corresponding catch. 7. Cowl doors according to claim 6, wherein said portion of the lock is a cylindrical finger which is parallel to the catch drive shaft and which is connected to said shaft by one or two tabs perpendicular to the shaft and to the finger. 8. Cowl doors according to claim 1, wherein the catches hooked onto the hooking members in their unlocking position form means for moving the bottom longitudinal edges of the doors towards each other while they are being driven towards their locking position. 9. Cowl doors according to claim 1, wherein the locking position of the catches lies beyond a position of unstable equilibrium in which the catches are in alignment with the axis of the drive shaft and with the hinge axis of the hooking members. 10. Cowl doors according to claim 9, wherein, in said position of unstable equilibrium, the catches bear axially against the hooking means of the hooking members. 11. Cowl doors according to claim 1, wherein the catches are movable between their locking and unlocking positions by means of a handle connected to their rotary drive shaft. 12. Cowl doors according to claim 11, wherein the handle forms a force multiplying lever. 13. Cowl doors according to claim 11, wherein the handle is hinged to the first door about an axis parallel to the axis of the catch drive shaft and includes a rectilinear slot in which there is engaged a finger carried by the drive shaft and off-center relative thereto.
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BACKGROUND OF THE INVENTION Cowl doors are panels of semicylindrical shape having top longitudinal edges hinged about longitudinal axes and having bottom longitudinal edges fitted with locking means that enable them to be fastened to each other in a position where they are close together or docked. The locking means are formed by locks distributed along the bottom longitudinal edges of the doors, these locks comprising hooking levers carried by one of the doors and operated by hand independently of one another to engage on hooking fingers mounted on the other one of the doors. It has been found that cowl doors that have been opened for maintenance purposes are sometimes subsequently poorly reclosed, with some of the locks being forgotten or incompletely locked, and that can lead subsequently to the doors opening in flight and being torn off. Proposals have already been made for locking apparatuses that seek to reduce this risk, relying on signaling means that are associated with the locks and that are mounted so as to be clearly visible in order to attract attention when the locks are unlocked or badly locked. Known means of that type have nevertheless turned out to be relatively ineffective or else they are relatively complex and bulky, heavy and expensive. OBJECTS AND SUMMARY OF THE INVENTION A particular object of the invention is to provide a solution to the problem of making the locking of such doors safe in a manner that is simple, effective, and inexpensive. To this end, the invention provides turbojet cowl doors, each door having a top longitudinal edge hinged about a longitudinal axis and a bottom longitudinal edge for fastening by means of locking apparatus to a bottom longitudinal edge of the other door, the apparatus comprising locking members mounted on the bottom longitudinal edge of a first door and co-operating with hooking members mounted on the bottom longitudinal edge of a second door, wherein the locking members are catches each of which is fixed to a rotary drive shaft parallel to the hinge axis of the first door and is movable between a locking angular position and an unlocking angular position, and wherein each hooking member is mounted on the bottom longitudinal edge of the second door to pivot about an axis parallel to the hinge axis of the second door and comprises means for hooking onto a corresponding catch in order to be moved by said catch between a locking angular position and an unlocking angular position. Mounting the catches and the hooking members to turn on parallel axes enables locking to be performed in a manner that is very simple and very effective while also reducing the amount of space occupied inside the doors, the catches and the hooking members pivoting outwards from the doors on being unlocked. By pivoting outwards they are made clearly visible, which makes it easy to see whether or not the doors are locked. According to another characteristic of the invention, the catches are secured to a common rotary drive shaft and are movable simultaneously between their locking angular positions and their unlocking angular positions. This makes the doors much easier to lock and avoids any risk of forgetting to actuate one of the locking means, since the locking means are locked or unlocked simultaneously. According to another characteristic of the invention, the hooking members are independent from one another, each being associated with a return spring urging it towards the unlocking position. By means of this disposition, a hooking member is automatically returned or held in a visible unlocking position if the corresponding catch, for any reason whatsoever, fails to entrain it or fails to hold it in the locking position. In a particular embodiment of the invention, each hooking member is formed by a tab which is pivotally mounted at one end on the above-mentioned hinge axis and which includes at its opposite end a U-shaped notch whose opening faces towards the hinge axis and is designed to receive a portion of the corresponding catch. This portion of the lock is formed by a cylindrical finger which is parallel to the catch drive shaft and which is connected to said shaft by one or two tabs that are perpendicular to the shaft and to said finger. This embodiment of the invention is particularly simple and very reliable. In addition, the catches hooked onto the hooking members in their unlocking position form means for moving the bottom longitudinal edges of the doors towards each other while they are being driven towards their locking position. The actions of closing and of locking the doors thus become particularly simple and reliable, locking being ensured in the invention regardless of whether the doors are already positioned edge to edge or whether they are still slightly apart from each other. According to another characteristic of the invention, the locking position of the catches lies beyond a position of unstable equilibrium in which the catches are in alignment with the hinge axis of the hooking members. In this position of unstable equilibrium, the catches bear axially against the hooking means of the hooking members. This bearing force advantageously constitutes a hard point through which it is necessary to pass in order to bring the catches into their locking position, thereby naturally ensuring that the catches are held in this position. This improves locking safety. In a preferred embodiment of the invention, the catches are movable between their locking and unlocking positions by means of a handle connected to their rotary drive shaft, and the handle forms a lever for multiplying force. To do this, the handle can be hinged to the first door about an axis parallel to the axis of the catch drive shaft and can include a rectilinear slot in which there is received an off-center finger carried by the drive shaft. This embodiment enables locking force to be multiplied and also makes it possible to obtain a movement stroke for the catches over a large angle between their locking and unlocking positions, said stroke being, for example, 160° to 180° approximately when the corresponding angular displacement stroke of the handle is only about 90°. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and other characteristics, details, and advantages thereof will appear more clearly on reading the following description made by way of example with reference to the accompanying drawings, in which: FIG. 1 is a diagrammatic perspective view of two turbojet cowl doors; FIG. 2 is a front view showing the two doors in the closed position; FIG. 3 is a diagram showing a lock of the invention; FIGS. 4a to 4d are diagrams showing four stages in an operation of unlocking the doors; FIGS. 5a, 5b, and 5c show three stages in an operation of locking the doors; FIGS. 6a to 6e are diagrams showing five stages in an operation of docking and simultaneously locking the doors; FIGS. 7a to 7e are diagrams showing five stages in an operation of docking and simultaneous locking the doors when the catches are in the extended position; FIG. 8 is a diagram showing a handle of the locking device of the invention; and FIG. 9 is a diagram showing a particular way of mounting the handle. MORE DETAILED DESCRIPTION Reference is made initially to FIGS. 1 and 2 which are diagrams showing two turbojet cowl doors of conventional type, these doors being formed by two panels 10 that are substantially semicylindrical in shape, having respective top longitudinal edges 12 that are hinged about parallel longitudinal axes 14 by hinges or the like, and having respective bottom longitudinal edges 16 that are fitted with locking means 18 enabling them to be fastened securely together when the two doors 10 are in the closed position with their bottom longitudinal edges 16 being forced one against the other, as shown in FIG. 2. An example of locking means 18 of the invention is shown in FIG. 3. These locking means comprise firstly a catch 20 mounted on the bottom longitudinal edge 16 of a first door 10, the left-hand door in FIG. 3, and secondly a hooking member 22 mounted on the longitudinal edge 16 of the second door 10, the door on the right in FIG. 3. The catch 20 is constrained to turn with a longitudinal cylindrical rod 21 which is carried by the first door 10 and which extends parallel to the hinge axes 14 of the door, said rod 21 forming a shaft for turning the catch 20 between a locking position shown in FIG. 3 and a fully unlocking position shown in FIGS. 4d and 5a, for example. In this embodiment, the catch 20 comprises two fork-forming parallel arms 24 each having one end secured to the shaft 21 and connected together via their opposite ends by a cylindrical finger 26 extending parallel to the shaft 21. The hooking member 22 mounted on the bottom longitudinal edge 16 of the second door 10 comprises a tab 28 having one end mounted to turn freely on the second door 10 about an axis 30 parallel to the shaft 21, and having an opposite end carrying means for hooking onto the cylindrical finger 26 of the catch 20. In this embodiment, the hooking means are formed by a hook 32 which projects from the tab 28 towards the inside of the door 10 when in the locked position as shown in FIG. 3, and defining a U-shaped notch 36 for receiving the cylindrical finger 26 of the catch 20, the open end of the notch 36 facing towards the hinge pin 30. Beside the free end of the hooking member 22, the hook 32 is of a convex rounded shape, whereas the open end of the notch 36 is connected to the tab 28 via a concave rounded surface 34. In addition, a return spring 38 is associated with the hooking member 22 and is formed, for example, by a spiral spring wound around the axis 30 and having one end prevented from rotating, its other end being mounted on the hooking member 22 tending to pivot it towards its unlocking position as shown in FIGS. 4d and 5a, for example. The locking apparatus of the invention comprises a plurality of catches 20 and hooking members 22 of the type described above, which are distributed along the bottom longitudinal edges 16 of the doors 10, there being four of them, for example. The catches 20 are advantageously mounted on the same drive shaft 21, while the hooking members 22 are independent from one another and free to turn about the axis 30. The catch drive shaft 21 is itself driven by any suitable means, for example a handle of the type shown in FIG. 8 and described below. The operation of the apparatus of the invention is described below with reference to FIGS. 4a to 4d, 5a to 5c, 6a to 6e, and 7a to 7e. FIGS. 4a to 4d show four stages in unlocking the doors, the first stage shown in FIG. 4a comprising turning the shaft 21 in the direction indicated by the arrow away from the fully locked position as shown in FIG. 3. Turning the catch 20 leads to corresponding turning of the hooking member 22 which turns about the axis 30 in the direction indicated by the arrow until the cylindrical finger 26 of the catch separates from the notch 36 as shown in FIG. 4b. Thereafter, the shaft 21 continues to turn in the same direction as shown in FIG. 4c, but the hooking member 22 is no longer entrained by the catch and remains in the position shown in FIG. 4c, which is its unlocking position in which it projects from the doors 10 and is clearly visible. The return spring 38 of this locking member 22 holds it in this position. In FIG. 4d, the catch 20 is in its fully unlocked position, the hooking member 22 remaining in the above-mentioned unlocking position. The doors 10 can then be opened by being moved apart from each other as represented by arrows in FIG. 4d. The angular movement of the catch 20 between its locking and fully unlocking positions is about 170° in this example, while the angular movement of the hooking member 22 is about 45°. A first way of locking the doors is shown in FIGS. 5a, 5b, and 5c. In a first stage, the bottom edges of the two doors are moved towards each other until they are substantially touching, as shown in FIG. 5a. The hooking member 22 is held by its return spring in the unlocking position as shown, while the catch 20 is in its fully unlocking position in which its cylindrical finger 26 is in the vicinity of the end of the hooking member 22 hinged on the axis 30. The second stage of locking shown in FIG. 5b comprises turning the shaft 21 in the direction shown by the arrow, this brings the cylindrical finger 26 of the catch 20 into the open end of the U-shaped notch 36 in the hooking member. As the catch 20 continuous to turn in the direction shown, the cylindrical finger 26 of the catch comes to bear against the end edge of the notch 36 and causes the hooking member 22 to pivot towards its locking position. Complete locking is shown in FIG. 5c, where it can be seen that the hooking member 22 has returned into alignment with the bottom longitudinal edges 16 of the doors 10 and no longer projects outside the doors. The cylindrical finger 26 of the catch 20 lies a little beyond a position of unstable equilibrium in which its axis is in the plane containing the axis of the shaft 21 and the axis 30. In this position of unstable equilibrium, the cylindrical finger 26 presses against the bottom of the notch 36 and this can correspond to a hard point that helps keep the catch 20 and the hooking member 22 in their fully locked positions. Proper locking of all of the locking means 18 fitted to the doors 10 can be checked in a glance, since none of the catches 20 and none of the hooking members 22 should be projecting from the doors. FIGS. 6a to 6e show a locking operation that takes place when the bottom longitudinal edges 16 of the doors 10 are still a little way apart from each other, as shown in FIG. 6a. The longitudinal edges of the two doors 10 are initially approached a little as shown in FIG. 6b until the cylindrical fingers 26 of the catches 20 come level with the open ends of the notches 36 in the hooking members 22 which are held in their unlocking position by their return springs 38. The shaft 21 then turns the catches 20 to engage the cylindrical fingers 26 in the notches 36 of the hooking members 22, as shown in FIG. 6c, and this turning is continued so as to cause the hooking members 22 to pivot towards their locking positions, as shown in FIGS. 6d and 6e. Turning the shaft 21 from the position shown in FIG. 6c to the position shown in FIG. 6e has the effect of simultaneously moving the bottom longitudinal edges 16 of the doors 10 towards each other until they are substantially touching. Another way of locking is shown in FIGS. 7a to 7e, for the case when the catches 20 are in an intermediate position between their fully unlocking position and their locking position, and in which they project out from the doors 10 on which they are mounted. In this case, when the bottom longitudinal edges of the doors 10 are moved towards each other as shown in FIG. 7a, with the hooking members 22 being held in their unlocking position by their return springs 38, the cylindrical fingers 26 of the catches 20 will come into abutment against the convex outside surfaces of the hooks 32 of the hooking members 22, thereby causing them to pivot outwards away from the doors, as shown in FIGS. 7b and 7c until the fingers move past the ends of the hooks 32 of the hooking members 22 and come substantially up to the concave curved surfaces 34 of these hooking members, as shown in FIG. 7d. Thereafter, the shaft 21 carrying the catches 20 is turned in the direction shown by the arrow in FIG. 7e until full locking is achieved. In a preferred embodiment of the invention, the shaft 21 carrying the catches 20 is turned by means of a handle 44 which is shown in continuous lines in FIG. 8 in is locking position and in dashed lines in its unlocking position. The handle 44 forms a compound lever and is hinged to the first door 10 on which the shaft 21 is mounted for turning the catches, about an axis 46 that is parallel to the shaft 21. The handle 44 is formed by a U-shaped plate or by an I-shaped plate having one wall 48 perpendicular to the axis 46 and including a slot 50 in which there is engaged a finger 52 that is parallel to the shaft 21 and that is off-center relative thereto, the finger 52 being carried by the shaft 21. By way of example, the finger 52 is formed by an extension of a cylindrical finger 26 of a catch 20. When the handle 44 is in the locking position shown in continuous lines in FIG. 8, it extends the bottom longitudinal edges 16 of the door panels 10 and is not visible. In order to unlock the door panels, the handle 44 is turned about its hinge axis 46 so as to bring it into the position shown in dashed lines, with the angular movement of the door between its locking and unlocking positions being slightly greater than 90° in this example. This turning of the handle leads to corresponding turning of the finger 52 about the axis 46 and to said finger being moved along a major fraction of the slot 50, and causes the catches 20 and their shaft 21 to turn about the axis of the shaft 21 through about 170°. The length of the handle relative to its hinge axis 46 is several times greater than that of the catches 20 so that the handle acts as a force multiplier while also multiplying the angular travel of the catches 20 about the axis of the shaft 21. This shaft is guided to turn in smooth bearings of conventional type carried by the first door 10. The handle 44 may be mounted at one end of the shaft 21 or on an intermediate portion thereof. When the bottom longitudinal edges 16 of the doors 10 are of a curved longitudinal shape as shown diagrammatically in FIG. 9, it is preferable for the shaft 21 to be made up of two shaft segments 21a and 21b placed end to end and forming chords between the ends of the edges 16 and their middle, the handle 44 then being placed at the junction between 21a and 21b. This avoids using a single rectilinear shaft 21 which would extend over the entire length of the bottom longitudinal edge 16 of the door, as represented by a chain-dotted line, since that would occupy too much space inside the doors, which would be troublesome.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Cowl doors are panels of semicylindrical shape having top longitudinal edges hinged about longitudinal axes and having bottom longitudinal edges fitted with locking means that enable them to be fastened to each other in a position where they are close together or docked. The locking means are formed by locks distributed along the bottom longitudinal edges of the doors, these locks comprising hooking levers carried by one of the doors and operated by hand independently of one another to engage on hooking fingers mounted on the other one of the doors. It has been found that cowl doors that have been opened for maintenance purposes are sometimes subsequently poorly reclosed, with some of the locks being forgotten or incompletely locked, and that can lead subsequently to the doors opening in flight and being torn off. Proposals have already been made for locking apparatuses that seek to reduce this risk, relying on signaling means that are associated with the locks and that are mounted so as to be clearly visible in order to attract attention when the locks are unlocked or badly locked. Known means of that type have nevertheless turned out to be relatively ineffective or else they are relatively complex and bulky, heavy and expensive.
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<SOH> OBJECTS AND SUMMARY OF THE INVENTION <EOH>A particular object of the invention is to provide a solution to the problem of making the locking of such doors safe in a manner that is simple, effective, and inexpensive. To this end, the invention provides turbojet cowl doors, each door having a top longitudinal edge hinged about a longitudinal axis and a bottom longitudinal edge for fastening by means of locking apparatus to a bottom longitudinal edge of the other door, the apparatus comprising locking members mounted on the bottom longitudinal edge of a first door and co-operating with hooking members mounted on the bottom longitudinal edge of a second door, wherein the locking members are catches each of which is fixed to a rotary drive shaft parallel to the hinge axis of the first door and is movable between a locking angular position and an unlocking angular position, and wherein each hooking member is mounted on the bottom longitudinal edge of the second door to pivot about an axis parallel to the hinge axis of the second door and comprises means for hooking onto a corresponding catch in order to be moved by said catch between a locking angular position and an unlocking angular position. Mounting the catches and the hooking members to turn on parallel axes enables locking to be performed in a manner that is very simple and very effective while also reducing the amount of space occupied inside the doors, the catches and the hooking members pivoting outwards from the doors on being unlocked. By pivoting outwards they are made clearly visible, which makes it easy to see whether or not the doors are locked. According to another characteristic of the invention, the catches are secured to a common rotary drive shaft and are movable simultaneously between their locking angular positions and their unlocking angular positions. This makes the doors much easier to lock and avoids any risk of forgetting to actuate one of the locking means, since the locking means are locked or unlocked simultaneously. According to another characteristic of the invention, the hooking members are independent from one another, each being associated with a return spring urging it towards the unlocking position. By means of this disposition, a hooking member is automatically returned or held in a visible unlocking position if the corresponding catch, for any reason whatsoever, fails to entrain it or fails to hold it in the locking position. In a particular embodiment of the invention, each hooking member is formed by a tab which is pivotally mounted at one end on the above-mentioned hinge axis and which includes at its opposite end a U-shaped notch whose opening faces towards the hinge axis and is designed to receive a portion of the corresponding catch. This portion of the lock is formed by a cylindrical finger which is parallel to the catch drive shaft and which is connected to said shaft by one or two tabs that are perpendicular to the shaft and to said finger. This embodiment of the invention is particularly simple and very reliable. In addition, the catches hooked onto the hooking members in their unlocking position form means for moving the bottom longitudinal edges of the doors towards each other while they are being driven towards their locking position. The actions of closing and of locking the doors thus become particularly simple and reliable, locking being ensured in the invention regardless of whether the doors are already positioned edge to edge or whether they are still slightly apart from each other. According to another characteristic of the invention, the locking position of the catches lies beyond a position of unstable equilibrium in which the catches are in alignment with the hinge axis of the hooking members. In this position of unstable equilibrium, the catches bear axially against the hooking means of the hooking members. This bearing force advantageously constitutes a hard point through which it is necessary to pass in order to bring the catches into their locking position, thereby naturally ensuring that the catches are held in this position. This improves locking safety. In a preferred embodiment of the invention, the catches are movable between their locking and unlocking positions by means of a handle connected to their rotary drive shaft, and the handle forms a lever for multiplying force. To do this, the handle can be hinged to the first door about an axis parallel to the axis of the catch drive shaft and can include a rectilinear slot in which there is received an off-center finger carried by the drive shaft. This embodiment enables locking force to be multiplied and also makes it possible to obtain a movement stroke for the catches over a large angle between their locking and unlocking positions, said stroke being, for example, 160° to 180° approximately when the corresponding angular displacement stroke of the handle is only about 90°.
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20040702
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20060509
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20050303
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66219.0
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BAREFOOT, GALEN L
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LOCKING THE COWL DOORS OF A TURBOJET
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,882,241
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ACCEPTED
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Transgenic mice having a human major histocompatibility complex (MHC) phenotype, experimental uses and applications
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The present invention relates to transgenic mice and isolated transgenic mouse cells, the mice and mouse cells comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. In embodiments, the transgenic mouse or mouse cells are deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene. In embodiments, the transgenic mouse or mouse cell has the genotype HLA-A2+HLA-DR1+β2m°IAβ°. The invention also relates to methods of using a transgenic mouse of the invention.
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1. A transgenic mouse comprising: a) a disrupted H2 class I gene; b) a disrupted H2 class II gene; and c) a functional HLA class I or class II transgene. 2. A transgenic mouse comprising: a) a disrupted H2 class I gene; b) a disrupted H2 class II gene; c) a functional HLA class I transgene; and d) a functional HLA class II transgene. 3. The transgenic mouse according to claim 2, wherein the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. 4. The transgenic mouse according to claim 3, wherein the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. 5. A transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene. 6. The transgenic mouse according to claim 5, having the genotype HLA-A2+HLA-DR1+β2m°IAβ°. 7. The transgenic mouse according to claim 6, wherein the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. 8. A method of simultaneously identifying the presence of one or more epitopes in a candidate antigen or group of antigens, wherein the epitope elicits a specific humoral response, a TH HLA-DR1 restricted response, and/or a CTRL HLA-A2 restricted response, the method comprising: a) administering the candidate antigen or group of candidate antigens to the mouse of claim 3 or claim 6; b) assaying for a specific humoral response in the mouse to the antigen; c) assaying for a TH HLA-DR1 restricted response in the mouse to the antigen; and d) assaying for a CTRL HLA-A2 restricted response in the mouse to the antigen; wherein, observation of a specific humoral response in the mouse to the antigen identifies an epitope which elicits a humoral response in the antigen; observation of a TH HLA-DR1 restricted response in the mouse to the antigen identifies an epitope which elicits a TH HLA-DR1 restricted response in the antigen; and observation of a CTRL HLA-A2 restricted response in the mouse to the antigen identifies an epitope which elicits a CTRL HLA-A2 restricted response in the antigen. 9. The method of claim 8, further comprising assaying for a Th1-specific response in the mouse to the antigen and assaying for a Th2-specific response in the mouse to the antigen; wherein observation of a Th1-specific response in the mouse to the antigen identifies an epitope which elicits a Th1-specific response in the mouse to the antigen; and observation of a Th2-specific response in the mouse to the antigen identifies an epitope which elicits a Th2-specific response in the mouse to the antigen. 10. A method of identifying the presence of an HLA DR1-restricted T helper epitope in a candidate antigen or group of candidate antigens, the method comprising: a) administering the candidate antigen or group of candidate antigens to the mouse of claim 3 or claim 6; and b) assaying for a TH HLA-DR1 restricted T helper epitope response in the mouse to the antigen; wherein, observation of a TH HLA-DR1 restricted T helper epitope response in the mouse to the antigen identifies an epitope which elicits a TH HLA-DR1 restricted T helper epitope response in the antigen. 11. An isolated antigen comprising an HLA DR1-restricted T helper epitope identified by the method of claim 10. 12. The isolated antigen of claim 11, wherein the antigen further comprises an epitope which elicits a humoral response and/or an epitope which elicits a CTRL HLA-A2 restricted response. 13. The isolated antigen of claim 11, wherein the antigen comprising an HLA DR1-restricted T helper epitope comprises a polypeptide. 14. The isolated antigen of claim 11, wherein the antigen comprising an HLA DR1-restricted T helper epitope comprises a polynucleotide. 15. The isolated antigen of claim 14, wherein the antigen comprising an HLA DR1-restricted T helper epitope comprises, DNA, RNA, or DNA and RNA. 16. A method of identifying the presence of an HLA-A2-restricted T cytotoxic (CTL) epitope in a candidate antigen or group of candidate antigens, the method comprising: a) administering the candidate antigen or group of candidate antigens to the mouse of claim 3 or claim 6; and b) assaying for an HLA-A2-restricted T cytotoxic (CTL) response in the mouse to the antigen or group of antigens; wherein, observation of an HLA-A2-restricted T cytotoxic (CTL) response in the mouse to the antigen or group of antigens identifies an epitope which elicits a an HLA-A2-restricted T cytotoxic (CTL) response in the antigen group of antigens. 17. An isolated antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope identified by the method of claim 16. 18. The isolated antigen of claim 17, wherein the antigen further comprises an epitope which elicits a humoral response and/or an epitope which elicits a TH HLA-DR1 restricted T helper epitope response. 19. The isolated antigen of claim 17, wherein the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises a polypeptide. 20. The isolated antigen of claim 17, wherein the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises a polynucleotide. 21. The isolated antigen of claim 20, wherein the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises, DNA, RNA, or DNA and RNA. 22. A method of comparing the efficiency of T-helper cell response induced by two or more vaccines, the method comprising: a) administering a first candidate vaccine to a mouse of claim 3 or claim 6 and measuring the T-helper cell response induced in the mouse by the first candidate vaccine; b) administering a second candidate vaccine to a mouse of claim 3 or claim 6 and measuring the T-helper cell response induced in the mouse by the second candidate vaccine; c) administering each additional candidate vaccine to be compared to a mouse of claim 3 or claim 6 and measuring the T-helper cell response induced in the mouse by each additional candidate vaccine to be compared; and d) determining the efficiency of each candidate vaccine to induce a T-helper cell response by comparing the T-helper cell responses to each of the vaccines to be compared with each other. 23. The method of claim 22, wherein the T-helper cell response is an HLA-DR1 restricted response. 24. A method of comparing the efficiency of T cytotoxic cell response induced by two or more vaccines, the method comprising: a) administering a first candidate vaccine to a mouse of claim 3 or claim 6 and measuring the T cytotoxic cell response induced in the mouse by the first candidate vaccine; b) administering a second candidate vaccine to a mouse of claim 3 or claim 6 and measuring the T cytotoxic cell response induced in the mouse by the second candidate vaccine; c) administering each additional candidate vaccine to be compared to a mouse of claim 3 or claim 6 and measuring the T cytotoxic cell response induced in the mouse by each additional candidate vaccine to be compared; and d) determining the efficiency of each candidate vaccine to induce a T cytotoxic cell response by comparing the T cytotoxic cell responses to each of the vaccines to be compared with each other. 25. The method of claim 24, wherein the T cytotoxic cell response is an HLA-A2 restricted response. 26. A method of simultaneously comparing the efficiency of T-helper cell response and T cytotoxic cell response induced by two or more vaccines, the method comprising: a) administering a first candidate vaccine to a mouse of claim 3 or claim 6 and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by the first candidate vaccine; b) administering a second candidate vaccine to a mouse of claim 3 or claim 6 and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by the second candidate vaccine; c) administering each additional candidate vaccine to be compared to a mouse of claim 3 or claim 6 and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by each additional candidate vaccine to be compared; and d) determining the efficiency of each candidate vaccine to induce a T-helper cell response and T cytotoxic cell response by comparing the T-helper cell response and T cytotoxic cell response to each of the vaccines to be compared with each other. 27. The method of claim 26, wherein the T-helper cell response is an HLA-DR1 restricted response, and wherein the T cytotoxic cell response is an HLA-A2 restricted response. 28. A method of simultaneously determining the humoral response, the T-helper cell response, and the T cytotoxic cell response of a mouse following its immunization with an antigen or a vaccine comprising one or more antigens, the method comprising: a) administering the antigen or the vaccine comprising one or more antigens to a mouse of claim 3 or claim 6; b) assaying for a specific humoral response in the mouse to the antigen or vaccine comprising one or more antigens; c) assaying for a T-helper cell response in the mouse to the antigen or vaccine comprising one or more antigens; and d) assaying for a T cytotoxic cell response in the mouse to the antigen or vaccine comprising one or more antigens. 29. The method of claim 28, wherein the T-helper cell response is a TH HLA-DR1 restricted response. 30. The method of claim 28, wherein the T cytotoxic cell response is a CTRL HLA-A2 restricted response. 31. A method of optimizing two or more candidate vaccine compositions for administration to a human, based on preselected criteria, the method comprising: simultaneously determining the humoral response, the T-helper cell response, and the T cytotoxic cell response of a mouse following its immunization with the two or more candidate vaccine compositions, according to claim 28; and selecting an optimized vaccine by applying preselected criteria to the results. 32. The method according to claim 31, wherein the two or more candidate vaccines differ only in the ratio of antigen to adjuvant present in the vaccine. 33. The method according to claim 31, wherein the two or more candidate vaccines differ only in the type of adjuvant present in the vaccine. 34. A method of determining whether a vaccine poses a risk of induction of an autoimmune disease when administered to a human, the method comprising: a) administering the vaccine to a mouse of claim 3 or claim 6; and b) assaying for an autoimmune response in the mouse; wherein, observation of an autoimmune response in the mouse indicates that the vaccine poses a risk of induction of an autoimmune disease when administered to a human. 35. An isolated transgenic mouse cell comprising: a) a disrupted H2 class I gene; b) a disrupted H2 class II gene; and c) a functional HLA class I or class II transgene. 36. An isolated transgenic mouse cell comprising: a) a disrupted H2 class I gene; b) a disrupted H2 class II gene; c) a functional HLA class I transgene; and d) a functional HLA class II transgene. 37. The transgenic mouse cell according to claim 36, wherein the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. 38. The transgenic mouse cell according to claim 37, wherein the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. 39. An isolated transgenic mouse cell deficient for both H2 class I and class II molecules, wherein the transgenic mouse cell comprises a functional HLA class I transgene and a functional HLA class II transgene. 40. The transgenic mouse cell according to claim 39, having the genotype HLA-A2+HLA-DR1+β2m°IAβ°. 41. The transgenic mouse cell according to claim 40, wherein the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing.
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CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims the benefit of U.S. Provisional Application No. 60/490,945, filed Jul. 30, 2003 (Attorney Docket No. 03495.6093), the entire disclosure of which is relied upon and incorporated by reference herein for all purposes. BACKGROUND OF THE INVENTION Many vaccines are currently being developed for human cancer immunotherapy and for treatment of infectious diseases, such as malaria, AIDS, hepatitis C virus, and SARS. Given the rapidity with which new emerging pathogens can appear, it is important to improve animal models that could be used to evaluate vaccination strategies and the protective capacity of different epitopes quickly and reliably. Furthermore, in vivo studies are already required to assess crucial variables of vaccine behavior that are not easily evaluated or impossible to measure in vitro, such as vaccine immunogenicity, vaccine formulation, route of administration, tissue distribution, and involvement of primary and secondary lymphoid organs. Because of their simplicity and flexibility, small animals, such as mice represent an attractive alternative to more cumbersome and expensive model systems, such as nonhuman primates, at least for initial vaccine development studies. The moderate efficacy observed in several clinical trials of vaccines, which were found to be protective in wild-type animal studies (McMichael, A. J. & Hanke, T. Nat Med 9, 874-880 (2003)), may be partly explained by the different influence that human and animal MHC have on the outcome of the immune response, since animal MHC and human HLA molecules do not present the same optimal epitopes (Rotzschke, O. et al. Nature 348, 252-254 (1990)). Thus, despite some limitations, transgenic mice expressing human HLA should represent a useful improvement over wild-type mice as a preclinical model for testing vaccine candidates, evaluating the potential risk that the vaccines could induce autoimmune disorders, and devising better therapeutic strategies based on the human restriction element. Cytotoxic T Cells Cytotoxic T cells (CTL) play a crucial role in the eradication of infectious diseases and in some cases, cancer (P. Aichele, H. Hengartner, R. M. Zinkernagel and M. Schulz, J Exp Med 171 (1990), p.1815; L. BenMohamed, H. Gras-Masse, A. Tartar, P. Daubersies, K Brahimi, M. Bossus, A. Thomas and P. Druhile, Eur J Immunol 27 (1997), p. 1242; D. J. Diamond, J. York, J. Sun, C. L. Wright and S. J. Forman, Blood 90 (1997), p. 1751). Recombinant protein vaccines do not reliably induce CTL responses (Habeshaw J A, Dalgleish A G, Bountiff L, Newell A L, Wilks, D, Walker L C, Manca F. November 1990; 11 (11): 418-25; Miller S B, Tse H, Rosenspire A J, King S R. Virology. December 1992; 191 (2):9 73-7). The use of otherwise immunogenic vaccines consisting of attenuated pathogens in humans is hampered, in several important diseases, by overriding safety concerns. In the last few years, epitope-based approaches have been proposed as a possible strategy to develop novel prophylactic and immunotherapeutic vaccines (Melief C J, Offringa R, Toes R E, Kast W M. Curr Opin Immunol. October 1996, 8(5):651-7; Chesnut R W, Design testing of peptide based cytotoxic T-cell mediated immunotherapeutic to treat infiction disease, cancer, in Ppowell, M F, Newman, M J (eds.): Vaccine Design: The Subunit, Adjuvant Approach, Plenum Press, New-York 1995, 847). This approach offers several advantages, including selection of naturally processed epitopes, which forces the immune system to focus on highly conserved and immunodominant epitopes of a pathogen (R. G. van der Most, A. Sette, C. Oseroff, J. Alexander, K. Murali-Krishna, L. L. Lau, S, Southwood, J. Sidney, R. W. Chesnut, M. Matioubian and R. Ahmed, J Immunol 157 (1996), p. 5543) and induction of multiepitopic responses to prevent escape by mutation such observed in HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. It also allows the elimination of suppressive T cell determinants, which might preferably elicit a TH2 response, in conditions where a TH1 responses is desirable, or vice-versa (Pfeiffer C, Murray J, Madri J, Bottomly K. Immunol Rev. October 1991; 123:65-84; P Chaturvedi, Q Yu, S Southwood, A Sette, and B Singh Int Immunol 1996 8: 745-755). It finally provides the possibility to get rid of autoimmune T cell determinants in antigens, which might induce undesirable autoimmune diseases. Protective antiviral or anti-tumoral immunity using CTL epitope-peptides has been achieved in several experimental models (D. J. Diamond, J. York, J. Sun, C. L. Wright and S. J. Forman, Blood 90 1997, p.1751; J. E. J. Blaney, E. Nobusawa, M. A. Brehm, R. H. Bonneau, L. M. Mylin, T. M. Fu, Y. Kawaoka and S. S. Tevethia, J Virol 72 (1998), p. 9567). CTL epitope definition based on the usage of human lymphocytes might be misleading due to environmental and genetic heterogeneity that lead to incomplete results, and due to technical difficulties in isolating CTL clones. HLA class I or class II transgenic mice described to date have proved to be a valuable tool to overcome these limitations as illustrated by the identification with such animal models of novel CTL and T helper epitopes (Hill A V. Annu Rev Immunol. 1998;16:593-617; Carmon L, El-Shami K M, Paz A., Pascolo S, Tzehoval E, Tirosb B, Koren R, Feldman M, Fridkin M, Lemonnier F A, Eisenbach L. Int J Cancer, Feb. 1, 2000; 85(3):391-7). These mice have also been used to demonstrate: i) good correlation between peptide HLA binding affinity and immunogenicity (Lustgarten J, Theobald M, Labadie C, LaFace D, Peterson P, Disis M L, Cheaver M A, Sherman L A. Hum Immunol. Febuary 1997; 52(2):109-18; Bakker A B, van der Burg S H, Huijbens R J, DRijfhout J W, Melief C J, Adema G J, Figdor C G. Int J Cancer. January 27, 1997; 70(3):302-9), ii) significant overlap between the murine and human CTL system at the level of antigen processing (same epitopes generated), and iii) comparable mobilization against most antigens of the CTL repertoires in HLA transgenic mice and humans (Wentworth, P. A., A. Vifiello, J. Sidney, E. Keogh, P, W. Chesnut, H. Grey, A. Sette. 1996. Eur. J. Immunol. 26:97; Alexander, J., C. Oserof, J. Sidney, P. Wentworth, E. Keogh, G. Hermanson, F. V. Chisari R. T, Kubo, H. M, Grey, A, Sette, 1997. J. Immunol. 159:4753). To date, synthetic peptide-based CTL epitope vaccines have been developed as immunotherapeutics against a number of human diseases [18-20]. However, only moderate efficacy was observed in several clinical trials (21). This may be partly explained by the failure of these vaccines to induce sufficiently strong CTL responses. Indeed, recent reports suggest the need for CD4+ T-cell help to obtain maximum CTL response (A. J. Zajac, K. Murali-Krishna, J. N. Blattman and R. Ahmed, Curr Opin Immunol 10 (1998), p. 444; Firat H, Garcia-Pons F, Tourdot S, Pascolo S, Scardino A, Garcia. Z, Michel M L, Jack R W, Jung O, Kosmatopoulos K, Mateo L, Suhrbier A, Lemonnier F A, Langlade-Dernoyen P Eur J Immunol 29, 3112,1999). CTL are critical components of protective immunity against viral infections, but the requirements for in vivo priming of CTL are not completely understood. It is now accepted that Th cells are usually essential for CTL priming with synthetic peptides. With respect to synthetic CTL epitopic peptides, several studies point to a mandatory need for Th lymphocyte stimulation to induce optimal CTL responses (C. Fayolle, E. Deriaud and C. Leclerc, J Immunol 147 (1991), p, 4069; C. Widmann, P. Romero, J. L. Maryanski, G. Corradin and D. Valmori, J Immunol Meth 155 (1992), p. 95; M. Shirai, C. D. Pendkton, J. Ahlers, T. Takeshita, M. Newman and J. A. Berzofsky, J Immunol 152 (1994), p. 549; J. P. Sauet, H. Gras-Masse, J. G. Guillet and E. Gomard, Int Immunol 8 (1996). p. 457). Several of these studies showed that activation of a CD8+ T cell requires simultaneous interaction of a CD4+ T helper cell and a CD8+ T cell with the same antigen-presenting cell presenting their cognate epitopes (Ridge J P, Di Rosa F, Matzinger P. Nature. Jun. 4, 1998; 3 93 (6684):474-8). The relevance of this three-cell interaction for priming of CTLs is confirmed by studies with viral epitopes, and animal models, since in vivo induction of CTLs was most efficient when CTL and Th epitopes were physically linked rather than administered as an unlinked mixture (Shirai M, Pendleton C D, Ahlers J, Takeshita T, Newman M, Berzohky J A. J Immunol. Jan. 15, 1994; 152(2): 549-56; Oseroff C, Sette A, Wentworth P, Celis E, Maewal A, Dahlberg C, Fikes J, Kubo R T, Chesnut R W, Grey B X Alexander J. Vaccine. May 1998; 16(8): 823-33). The capacity of CTL and Th antigenic peptides to efficiently induce CTL responses has been demonstrated both in experimental models (C. Fayolle, E. Deriaud and C. Leclerc, J Immunol 147 (1991), p, 4069; C. Widmann, P. Romero, J. L. Maryanski, G. Corradin and D. Valmori, J Immunol Meth 155 (1992), p. 95) and in humans (A. Vitiello, G. Ishioka, H. M. Grey, R. Rose, P. Famess, R. LaFond, L. Yuan, F. V. Chisari, J. Furze and R. Bartholomeuz, J Clin Invest 95 (1995), p. 341; B. Livingston, C. Crimi, H. Grey, G. Ishioka, F. V. Chisari, J. Fikes, H. M. Grey, R. Chesnut and A. Sette, J Immunol 159 (1997), p.1383). Moreover, a potent Th response plays an important role not only for optimal induction of CTL responses, but also for maintenance of CTL memory (E. A. Walter, P. D. Greenberg, M. J. Gilbert, R. J. Finch, K-S. Watanabe, E. D. Tbomas and S. R. Riddell, N Engl J Med 333 (1995), p.1038; Riddell S R, Greenberg P D, In Thomas E D, Blume K G, Forman S J (eds): Hematopoietic Cell Transplantation, 2nd edn. Maiden, MA: Blackwell Science Inc., 1999). Finally, it has long been documented that CD4+ T “helper” cells are crucial in coordinating cellular and humoral immune responses against exogenous antigens. Recently, a transgenic (Tg) mouse that expresses both HLA-A*0201 class I and HLA-DR1 class II molecules was established (BenMohamed L, Krishnan R, Longmate J, Auge C, Low L, Primus J, Diamond D J, Hum, Immunol. August 2000;61 (8):764-79). The authors reported that both HLA-A*0201 and HLA-DR1 transgenes are functional in vivo, that both MHC class I and class II molecules were utilized as restriction elements, and that the product of the HLA-DR1 transgene enhances the HLA-A*0201-restricted antigen-specific CTL responses (BenMohamed L, Krishnan R, Longmate J, Auge C, Low L, Primus J, Diamond D J, Hum, Immunol. August 2000;61 (8):764-79). It is noteworthy that these HLA-A*0201/DR1 Tg mice expressed their own MHC H-2 class I and class II molecules. Because HLA class I transgenic mice expressing endogenous mouse MHC class I genes preferentially and often exclusively develop H-2 restricted CTL response (C Barra, H Gournier, Z Garcia, P N Marche, E Jouvin-Marche, P Briand, P Fillipi, and F A Lemonnier J Immunol 1993 150: 3681-3689; Epstein H, Hardy F., May J S, Johnson M H, Holmes N. Eur J Immunol. September 1989;19(9):1575-83; Le A X; E J Bernhard, M J Holterman, S Strub, P Parham, E Lacy, and V H Engelhard J Immunol 1989 142: 13 66-1371; Vitiello A, Marchesini D, Furze J, Sherman L A, Chesnut R W., J Exp Med. Apr. 1, 1991;173(4):100715), and HLA class II transgenic mice expressing endogenous mouse MHC class II genes fail to induce reliable HLA class II restricted antigen-specific responses (Nishimura Y, Iwanaga T, Inamitsu T, Yanagawa Y, Yasunami M, Kimura A, Hirokawa K, Sasazuki T., J Immunol Jul. 1, 1990;145(1):353-60), these HLA-A*0201/DR1 Tg mice are of limited utility to assess human-specific responses to antigen. However, in HLA class I transgenic H-2 class I knock-out mice, or HLA class II transgenic H-2 class II knock-out mice, only HLA-restricted CTL immune responses occur (Pascolo S, Bervas N, Ure J M, Smith A G, Lemonnier F A, Perarnau, B., J Exp Med. Jun. 16, 1997;185(12).2043-51; Madsen L, Labrecque N, Engberg J, Dierich A, Svejgaard A, Benoist C, Mathis D, Fugger L. Proc Natl Acad Sci USA—Aug. 31, 1999;96(18):10338-43). In fact, HLA-A2.1-transgenic H-2 class I-knock-out (KO) mice exhibit the ability to mount enhanced HLA-A2.1-restricted responses as compared to HLA-A2.1-transgenic mice that still express the endogenous murine H-2 class I molecules (Pascolo, S. et al. J Exp Med 185, 2043-2051 (1997); Ureta-Vidal, A., Firat, H., Perarnau, B. & Lemonnier, F. A. J Immunol 163, 2555-2560 (1999); Firat, H. et al., Int Immunol 14, 925-934 (2002); Rohrlich, P. S. et al., Int Immunol 15, 765-772 (2003)). The inventors have made similar observations with HLA-DR1-transgenic mice, depending on whether or not they are deficient in H-2 class II molecules (A. Pajot, unpublished results). Furthermore, in the absence of competition from murine MHC molecules, the HLA-A2.1-transgenic H-2 class I-KO or HLA-DRI-transgenic H-2 class II-KO mice generate only HLA-restricted immune responses (Pascolo, S. et al. J Exp Med 185, 2043-2051 (1997)) (A. Pajot, unpublished results), facilitating the monitoring of HLA-restricted CD8+ and CD4+ T cell responses. However, protective immune responses against pathogens, which often require collaboration between T helper and cytotoxic CD8+ T cells, cannot be studied in the single HLA class I- or HLA class II-transgenic mice, which do not allow the simultaneous assessment of HLA class I and II human responses in the same mouse. Accordingly, there exists a need in the art for a convenient animal model system to test the immunogenicity of human vaccine candidates comprising constructs containing human CTL epitopes and, in some cases, with the inclusion of high potency CD4+ Th (helper T lymphocyte) epitopes to sustain antiviral and antitumoral CD8+ T-cell activity (A. J. Zajac, K. Murali-Krishna, J. N. Blattman and R. Ahmed, Curr Opin Immunol 10 (1998), p. 444; Firat H, Garcia-Pons F, Tourdot S, Pascolo S, Scardino A, Garcia Z, Michel M L, Jack R W, Jung O, Kosmatopoulos K, Mateo L, Suhrbier A, Lemonnier F A, Langlade-Dernoyen P, Eur J Immunol 29,3112, 1999). There is also a need for a system that allows the simultaneous assessment of the mutual coordination between a CTL response, a TH response (in particular s TH1 or TH2 response), and, optionally, a humoral response. SUMMARY OF THE INVENTION The inventors have met this need and more by providing mice transgenic for both HLA-A2.1 and HLA-DR1 molecules, in a background that is deficient for both H-2 class I and class II molecules. Specifically, the invention provides mice comprising (1) mutated H-2 class I and class II molecules; and (2) expressing HLA class I transgenic molecules, or HLA class II transgenic molecules, or HLA class I transgenic molecules and HLA class II transgenic molecules. These mice provide a model useful in the development and optimization of vaccine constructs with maximum in vivo immunogenicity for human use. Specifically, such mice enable a complete analysis of the three components of the immune adaptive response (antibody, helper and cytolytic) in a single animal, as well as an evaluation of the protection specifically conferred by vaccination against an antigenic challenge. Mice of the invention, which comprise a knock-out for both H-2 class I and class II molecules, and express HLA class I transgenic molecules and HLA class II transgenic molecules represent a completely humanized experimental mouse that can be used to simultaneously detect the presence of antigen-specific antibodies, an antigen-specific HLA-DRI restricted T cell response, and an antigen-specific HLA-A2 restricted T cell response. These mice will be useful to study how mutual coordination operates between a CTL response, a TH response (in particular a TH1 or TH2 response), and, optionally, a humoral response. These mice represent an optimized tool for basic and applied vaccinology studies. A first embodiment of the invention provides a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, and a functional HLA class I or class II transgene. A second embodiment of the invention provides a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. In some embodiments, the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. A further embodiment of the invention provides a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene. In an embodiment, the mouse has the genotype HLA-A2+HLA-DR1+β2m°IAβ°. In some embodiments the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. Another embodiment of the invention provides a method of simultaneously identifying the presence of one or more epitopes in a candidate antigen or group of antigens, where the one or more epitopes elicits a specific humoral response, a TH HLA-DR1 restricted response, and/or a CTRL HLA-A2 restricted response. The method comprises administering the candidate antigen or group of candidate antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAα°; assaying for a specific humoral response in the mouse to the antigen; assaying for a TH HLA-DR1 restricted response in the mouse to the antigen; and assaying for a CTRL HLA-A2 restricted response in the mouse to the antigen. Observation of a specific humoral response in the mouse to the antigen identifies an epitope that elicits a humoral response in the antigen. Observation of a TH HLA-DR1 restricted response in the mouse to the antigen identifies an epitope that elicits a TH HLA-DR1 restricted response in the antigen. Observation of a CTRL HLA-A2 restricted response in the mouse to the antigen identifies an epitope which elicits a CTRL HLA-A2 restricted response in the antigen. In some embodiments, the method includes assaying for a Th1-specific response in the mouse to the antigen and assaying for a Th2-specific response in the mouse to the antigen. In this case, observation of a Th1-specific response in the mouse to the antigen identifies an epitope that elicits a Th1-specific response in the mouse to the antigen, and observation of a Th2-specific response in the mouse to the antigen identifies an epitope that elicits a Th2-specific response in the mouse to the antigen. This invention also provides a method of identifying the presence of an HLA DR1-restricted T helper epitope in a candidate antigen or group of candidate antigens, the method comprising administering the candidate antigen or group of candidate antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°; and assaying for a TH HLA-DR1 restricted T helper epitope response in the mouse to the antigen. Observation of a TH HLA-DR1 restricted T helper epitope response in the mouse to the antigen identifies an epitope that elicits a TH HLA-DR1 restricted T helper epitope response in the antigen. In addition, this invention provides an isolated antigen comprising an HLA DR1-restricted T helper epitope identified by the method of the preceding paragraph. In some embodiments, the isolated antigen further includes an epitope that elicits a humoral response and/or an epitope that elicits a CTRL HLA-A2 restricted response. In some embodiments, the antigen comprising an HLA DR1-restricted T helper epitope comprises a polypeptide. In other embodiments, the antigen comprising an HLA DR1-restricted T helper epitope comprises a polynucleotide. In further embodiments, the antigen comprising an HLA DR1-restricted T helper epitope comprises DNA, RNA, or DNA and RNA. Further, this invention provides a method of identifying the presence of an HLA-A2-restricted T cytotoxic (CTL) epitope in a candidate antigen or group of candidate antigens, the method comprising administering the candidate antigen or group of candidate antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°; and assaying for an HLA-A2-restricted T cytotoxic (CTL) response in the mouse to the antigen or group of antigens. Observation of an HLA-A2-restricted T cytotoxic (CTL) response in the mouse to the antigen or group of antigens identifies an epitope that elicits a an HLA-A2-restricted T cytotoxic (CTL) response in the antigen or group of antigens. This invention provides an isolated antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope identified by the method of the preceding paragraph. In some embodiments, the antigen further comprises an epitope that elicits a humoral response and/or an epitope that elicits a TH HLA-DR1 restricted T helper epitope response. In some embodiments, the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises a polypeptide. In other embodiments, the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises a polynucleotide. In further embodiments, the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises, DNA, RNA, or DNA and RNA. This invention also provides a method of comparing the efficiency of the T-helper cell response induced by two or more vaccines. This method comprises administering a first candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T-helper cell response induced in the mouse by the first candidate vaccine; administering a second candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T-helper cell response induced in the mouse by the second candidate vaccine; administering each additional candidate vaccine to be compared to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T-helper cell response induced in the mouse by the additional candidate vaccine, and determining the efficiency of each candidate vaccine to induce a T-helper cell response by comparing the T-helper cell responses to each of the vaccines to be compared with each other. In some embodiments the T-helper cell response is an HLA-DR1 restricted response. In addition, this invention provides a method of comparing the efficiency of T cytotoxic cell responses induced by two or more vaccines. The method includes administering a first candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T cytotoxic cell response induced in the mouse by the first candidate vaccine; administering a second candidate vaccine to a mouse of a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T cytotoxic cell response induced in the mouse by the second candidate vaccine; administering each additional candidate vaccine to be compared to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T cytotoxic cell response induced in the mouse by the additional candidate vaccine; and determining the efficiency of each candidate vaccine to induce a T cytotoxic cell response by comparing the T cytotoxic cell responses to each of the vaccines to be compared with each other. In some embodiments the T cytotoxic cell response is an HLA-A2 restricted response. Further, this invention provides a method of simultaneously comparing the efficiency of T-helper cell response and T cytotoxic cell response induced by two or more vaccines. The method comprises administering a first candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by the first candidate vaccine; administering a second candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by the second candidate vaccine; administering each additional candidate vaccine to be compared to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by each additional candidate vaccine; and determining the efficiency of each candidate vaccine to induce a T-helper cell response and T cytotoxic cell response by comparing the T-helper cell response and T cytotoxic cell response to each of the vaccines to be compared with each other. In some embodiments the T-helper cell response is an HLA-DR1 restricted response, and the T cytotoxic cell response is an HLA-A2 restricted response. This invention also provides a method of simultaneously determining the humoral response, the T-helper cell response, and the T cytotoxic cell response of a mouse following its immunization with an antigen or a vaccine comprising one or more antigens. The method comprises administering the antigen or the vaccine comprising one or more antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and assaying for a specific humoral response in the mouse to the antigen or vaccine comprising one or more antigens, assaying for a T-helper cell response in the mouse to the antigen or vaccine comprising one or more antigens, and assaying for a T cytotoxic cell response in the mouse to the antigen or vaccine comprising one or more antigens. In some embodiments the T-helper cell response is a TH HLA-DR1 restricted response. In some embodiments the T cytotoxic cell response is a CTRL HLA-A2 restricted response. This invention also provides a method of optimizing two or more candidate vaccine compositions for administration to a human, based on preselected criteria. The method includes simultaneously determining the humoral response, the T-helper cell response, and the T cytotoxic cell response of a mouse following its immunization with the two or more candidate vaccine compositions, using a method comprising administering the antigen or the vaccine comprising one or more antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, assaying for a specific humoral response in the mouse to the antigen or vaccine comprising one or more antigens, assaying for a T-helper cell response in the mouse to the antigen or vaccine comprising one or more antigens, assaying for a T cytotoxic cell response in the mouse to the antigen or vaccine comprising one or more antigens, and selecting an optimized vaccine by applying preselected criteria to the results. In some embodiments, the two or more vaccine candidates differ only in the ratio of antigen to adjuvant present in the vaccine. In some embodiments, the two or more vaccine candidates differ only in the type of adjuvant present in the vaccine. In another aspect, the invention provides a method of determining whether a vaccine poses a risk of induction of an autoimmune disease when administered to a human. The method comprises administering the vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2+HLA-DR1+β2m°IAβ°, and assaying for an autoimmune response in the mouse, where observation of an autoimmune response in the mouse indicates that the vaccine poses a risk of induction of an autoimmune disease when administered to a human. This invention also provides an isolated transgenic mouse cell comprising a disrupted H2 class I gene, a disrupted H2 class II gene, and a functional HLA class I or class II transgene. In addition, the invention provides an isolated transgenic mouse cell comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. In some embodiments, the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. Further, this invention provides an isolated transgenic mouse cell deficient for both H2 class I and class II molecules, wherein the transgenic mouse cell comprises a functional HLA class I transgene and a functional HLA class II transgene. In some embodiments, the transgenic mouse cell has the genotype HLA-A2+HLA-DR1+β2m°IAβ°. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully described with reference to the drawings in which: FIG. 1 shows a flow cytometric analysis of the cell-surface expression of the indicated transgenic molecules. (a) Splenocytes from HLA-DR1-transgenic H-2 class II-KO (DR1+ CII−, left panel), HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO (A2+ DR1+ CI− CII−, central panel), and HLA-A2.1-transgenic H-2 class I-KO (A2+ CI−, right panel) mice were stained with either FITC-labeled W6/32 (anti-HLA-ABC, in abcissas) or biotinylated 28-8-6S (anti-H-2Kb/Db, in ordinates) m.Ab, the latter revealed with PE-labeled anti-mouse IgG. (b) B220+ splenic B lymphocytes from the same strains of mice, were stained with FITC-labeled L243 (anti-HLA-DR1, upper panels) and PE-labeled AF6-120.1 (anti-H-2 IAβb, lower panels) m.Ab. FIG. 2 shows CD8+ and CD4+ splenic T cell numbers and BV segment usage (based on an immunoscope analysis) in mice of the indicated genotypes. (a) Splenocytes from HLA-DR1-transgenic H-2 class II-KO (DR1+ CII−, left panel), HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO (A2+ DR1+ CI− CII−, central panel), and HLA-A2.1-transgenic H-2 class I-KO (A2+ CI−, right panel) mice were stained with PE-labeled CT-CD4 (anti-mouse CD4, in ordinates) and FITC-labeled 53-6.7 (anti-mouse CD8, in abcissas) m.Ab. Numbers correspond to percentages of CD4+ (upper left square) or CD8+ (lower right square) T cells in total splenocytes. (b and c) Immunoscope RT-PCR analysis of purified splenic CD8+(b) and CD4+ (c) T cells for BV segment family (1-20) usage using forward BV family (1-20) specific and reverse BC primers. A typical profile for a BV segment family productively rearranged includes a series of peaks with a Gaussian-like distribution differing in length by 3 nucleotides. The Figure illustrates the results obtained with a HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO representative mouse. FIG. 3 shows HBs-specific antibody, cytolytic and proliferative responses. HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO mice were or not immunized by intramuscular injection of HBsAg-encoding plasmid-DNA and then individually tested. (a) Humoral (upper panel), cytolytic (middle panel) and proliferative (lower panel) responses and specificity controls of a representative HBsAg-DNA-immunized mouse. The antibody (IgG) titer against HBsAg particles containing both middle and small HBV envelope proteins and against the preS210-134 peptide were determined in an ELISA assay. Cytolytic activity at different effector/target (E/T) ratios was assessed using RMAS-HHD target cells pulsed with either relevant (HBsAg348-357, HLA-A2.1-restricted ♦) or control (HBsAg371-378, H-2 Kb-restricted Δ, and MAGE-3271-279, HLA-A2.1-restricted ) peptide. Proliferative responses were detected using either relevant (HBsAg180-195, HLA-DR1-restricted) or control (HBsAg126-138, H-2 IAb-restricted and HIV 1 Gag263-278, HLA-DR1-restricted) peptide. (b) Similar evaluation of the antibody (IgG, upper panel), cytolytic (middle panel) and proliferative (lower panel) responses of 6 (1-6) HBsAg-DNA-immunized mice as compared to mean responses of 6 naive mice (0). Cytolytic activity at a 30/1 E/T ratio was assessed on RMAS-HHD target cells pulsed with either HBsAg348-357, immunodominant (filled bars) or HBsAg335-343, subdominant (grey bars) peptide. FIG. 4 shows results of protection assays. HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-/KO mice were or not immunized twice with plasmid DNA encoding HBsAg. Fifteen days after the last immunization, they were challenged intraperitoneally with 107 PFU of rVV expressing either the HBsAg or the HBx protein. Four days later, animals were tested individually for viral titers in ovaries. The results (rVV PFU/ovary in log 10) are given for the HBsAg-DNA-immunized mice challenged with rVV-HBsAg (I, n=10), naive mice challenged with rVV-HBsAg (N, n=6), HBsAg-immune mice challenged with rVV-HBx (Ix, n=6) and naive mice challenged with rVV-HBx (Nx, n=6). FIG. 5 shows the AC anti-Pre S2 response in HLA-A2+DR1+CI−CII− mice following a pcmv S2/S immunization. FIG. 6 shows the T CD4 proliferative response to HLA-DR1 restricted epitopes following immunization of HLA-A2+DR1+CI−CII− mice with pcmv S2-S. FIG. 7 shows the T CD8 cytotoxic response to the HLA-A2 restricted HBS (348-357) peptide following an immunization of HLA-A2+DR1+CI−CII− mice with pcmv S2/S. SEQUENCES SEQ ID NO:1 contains the following subparts: Nucleotides 1-1205 comprise the HLA-A2 promoter; nucleotides 1206-1265 the HLA-A2 leader sequence; nucleotides 1266-1565 the human β2 microgobulin cDNA; nucleotides 1566-1610 a (Gly4Ser)3 linker; nucleotides 1611-2440 a segment containing exon 2 and part of intron 3 of HLA-A2; and nucleotides 2441-4547 a segment containing part of intron 3, exons 4 to 8, and part of the 3′ non-coding region of the H2Db gene. SEQ ID NO:2 is the nucleotide sequence of the DRA*0101 gene. Nucleotides 1-15279 are the promoter located 5′ to the HLA-DR alpha gene, nucleotides 15280-15425 are exon 1, nucleotides 15344-15346 are the ATG start codon, nucleotides 17838-18083 are exon 2, nucleotides 18575-18866 are exon 3, nucleotides 19146-19311 are exon 4, and nucleotides 20008-20340 are exon 5. SEQ ID NO:3 is the nucleotide sequence of the DRB1*010101 gene. Nucleotides 7391-7552 are exon 1, nucleotides 7453-7455 are the ATG start codon, nucleotides 15809-16079 are exon 2, nucleotides 19536-19817 are exon 3, nucleotides 20515-20624 are exon 4, nucleotides 21097-21121 are exon 5, and nucleotides 21750-22085 are exon 6. DETAILED DESCRIPTION OF THE INVENTION The practice of the present invention will employ, unless otherwise indicated, conventional techniques of cell biology, cell culture, molecular biology, transgenic biology, microbiology, recombinant DNA, and immunology, which are within the skill of the art. Such techniques are explained fully in the literature. See, for example, Molecular Cloning A Laboratory Manual, 2nd Ed., ed. by Sambrook, Fritsch and Maniatis (Cold Spring Harbor Laboratory Press:1989); DNA Cloning, Volumes I and II (D. N. Glover ed., 1985); Oligonucleotide Synthesis (M. J. Gait ed., 1984); Mullis et al. U.S. Pat. No. 4,683,195; Nucleic Acid Hybridization (B. D. Hames & S. J. Higgins eds. 1984); Transcription And Translation (B. D. Hames & S. J. Higgins eds. 1984); Culture Of Animal Cells (R. I. Freshney, Alan R. Liss, Inc., 1987); Immobilized Cells And Enzymes (IRL Press, 1986); B. Perbal, A Practical Guide To Molecular Cloning (1984); the series, Methods In ENZYMOLOGY (J. Abelson and M. Simon, eds.-in-chief, Academic Press, Inc., New York), specifically, Vols.154 and 155 (Wu et al. eds.) and Vol.185, “Gene Expression Technology” (D. Goeddel, ed.); Gene Transfer Vectors For Mammalian Cells (J. H. Miller and M. P. Calos eds., 1987, Cold Spring Harbor Laboratory); Immunochemical Methods In Cell And Molecular Biology (Mayer and Walker, eds., Academic Press, London, 1987); Handbook Of Experimental Immunology, Volumes I-IV (D. M. Weir and C. C. Blackwell, eds., 1986); and Manipulating the Mouse Embryo, (Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1986). This invention provides mice comprising (1) mutated H-2 class I and class II molecules; and (2) expressing HLA class I transgenic molecules, or HLA class II transgenic molecules, or HLA class I transgenic molecules and HLA class II transgenic molecules. Mice of the invention, which comprise a knock-out for both H-2 class I and class II molecules, and express HLA class I transgenic molecules and HLA class II transgenic molecules represent a completely humanized experimental mouse that can be used to simultaneously detect the presence of antigen-specific antibodies, an antigen-specific HLA-DRI restricted T cell response, and an antigen-specific HLA-A2 restricted T cell response. These mice are useful to study how mutual coordination operates between a CTL response, a TH response (in particular a TH1 or TH2 response), and, optionally, a humoral response. These mice represent an optimized tool for basic and applied vaccinology studies. The invention provides transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, and a functional HLA class I or class II transgene. In some embodiments, the transgenic mouse comprises a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. Such a mouse can be said to be a completely humanized experimental mouse, because it can be used to simultaneously detect the presence of antigen-specific antibodies, an antigen-specific HLA-DRI restricted T cell response, and an antigen-specific HLA-A2 restricted T cell response. As shown, in part, in the Examples provided herein, and as is generally clear to one of skill in the art from the disclosure, HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO mice have the capacity to develop HBsAg-specific antibody, CD4+ helper and CD8+ cytolytic T cell responses following DNA immunization. These responses, observed in every single mouse tested, were directed at the same immunodominant epitopes as human responses and conferred to the immunized animals specific protection against a HBsAg recombinant vaccinia virus. T helper cells are essential for full maturation of antibody responses (Katz, D. H. & Benacerraf, B., Adv Immunol 15, 1-94 (1972)) CTL priming against many epitopes (von Boehmer, H. & Haas, W., J Exp Med 150, 1134-1142 (1979); Keene, J. A. & Forman, J., J Exp Med 155, 768-782 (1982)) and CTL long-term maintenance (Matloubian, M., Concepcion, R. J. & Ahmed, R., J Virol 68, 8056-8063 (1994)). Both antibodies (Lefrancois, L., J Virol 51, 208-214 (1984)) and CTL (Zinkernagel, R. M. & Welsh, R. M., J Immunol 117, 1495-1502 (1976)) are critical components of protective immunity against viral infections. Potent HBsAg-specific antibody and CTL responses were in fact observed in HLA-A2.1-/HLA-DR1-double transgenic, H-2 class I-/class II-KO mice, but not in HLA-A2.1-single transgenic, H-2 class I-/ class II-KO mice. Thus, HBsAg-specific CD4+ T cell help is essential for generating efficient HBsAg-specific CTL and antibody responses. These results are consistent with studies on HBsAg-immunized mice (Milich, D. R., Semin Liver Dis 11, 93-112(1991)) and HBsAg-vaccinated humans (Celis, E., Kung, P. C. & Chang, T. W., J Immunol 132, 1511-1516 (1984)), which suggest that production of an anti-HBs antibody response is dependent on CD4+ T cells. Transgenic mice expressing both HLA-A2.1 class I and HLA-DR1 class II molecules have already been derived (BenMohamed, L. et al. Hum Immunol 61, 764-779 (2000)). The authors reported that both the HLA-A2.I and HLA-DR1 molecules are functional restriction elements in vivo and that the product of the HLA-DR1 transgene enhances the HLA-A2.1-restricted antigen-specific CTL responses. However, the human relevance of the immune responses in these mice is dwarfed by the fact that they still expressed their own H-2 class I and class II molecules, which are usually preferentially and often exclusively used as restricting elements in response to antigens (Ureta-Vidal, A., Firat, H., Perarnau, B. & Lemonnier, F. A., J Immunol 163, 2555-2560 (1999); Rohrlich, P. S. et al., Int Immunol 15, 765-772 (2003)) (A. Pajot, unpublished results). The invention described herein overcomes this limitation by providing HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice. In some embodiments the HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice express, in a β2m-KO context, a HLA-A2.1 monochain in which the human β2m is covalently linked by a peptidic arm to the HLA-A2.1 heavy chain. They further lack cell surface expression of conventional H-2 IA and IE class II molecules as a result of the inactivation of the H-2 IAβb gene, since H-2 IEα is a pseudogene in the H-2b haplotype. The results provided herein demonstrate that such mice are deprived of cell surface expression of H-2 class I and class II molecules. However, it was reported in one case that a free class I heavy chain, in particular H-2 Db, may exist on the surface of a β2m-KO mouse, and could induce an alloreactivity response. Even if this is so, because such mice are empty of peptide, they should not interfere in antigen-specific immune response (Bix, M. & Raulet, D., J Exp Med 176, 829-834 (1992)). This is supported by the report of Allen et al (Allen, H., Fraser, J., Flyer, D., Calvin, S. & Flavell, R., Proc Natl Acad Sci USA 83, 7447-7451 (1986)), in which they confirmed that H-2 Db is expressed at the cell surface even when there is no β2m present within the cell, but that such Db antigen is recognized by neither Db-allospecific or Db-restricted cytotoxic T lymphocytes. Furthermore, Db antigens are not recognized by most monoclonal antibodies of the native Db. Nonetheless, in HLA-DRα single transgenic mice, it was reported that unconventional HLA-DRα/H-2 IEβb hybrid complexes may be expressed to some extent on the cell surface, at least in the absence of the HLA-DRβ chain (Lawrance, S. K. et al., Cell 58, 583-594 (1989)). In spite of this observation, these unconventional molecules were not detected serologically on cell surfaces in HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice, even with mAb (17-3-3S), which is known to react with such hybrid molecules (Ozato, K., Mayer, N. & Sachs, D. H., J Immunol 124, 533-540 (1980)) (FIG. 1a and data not shown). In addition, the results obtained on studying HBsAg-specific and HIV 1-Gag-specific T cell responses of these mice were all indicative of exclusive usage of the HLA-A2.1 and HLA-DR1 molecules as restricting elements. This argues that the unconventional HLA-DRα/H-2 IEβb hybrids were likely unstable compared to conventional HLA-DRα/HLA-DRβ molecules and that they may exist only in the absence of the HLA-DRβ chain. Mouse strains in which the entire (H-2 IAβb, IAαb, IEβb) H-2 class II region has been deleted (Madsen, L. et al., Proc Natl Acad Sci USA 96, 10338-10343 (1999)), as well as the H-2 Db gene, are being analyzed to completely exclude this possibility. Preliminary analysis of splenocytes obtained from the first animals revealed a CD4+ T cell pool restoration similar to that observed in HLA-DR1-transgenic H-2 class II-KO (Iaβb°) mice, suggesting that the HLA-DR1-restricted CD4+ T cell responses of these new mice should be equivalent to those of the HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice. The peripheral CD8+ T lymphocytes of HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice, compared to parental HLA-A2.1-transgenic H-2 class I-KO mice, are quantitatively and qualitatively similar with full diversification, at least in terms of BV segment usage, of the TCR repertoire. Partial restoration compared to wild-type animals, especially of the CD8+ T cell pool, has been a constant observation in single HLA-transgenic mice expressing a chimeric (α3 domain of mouse origin) HLA-A2.1 molecule (Pascolo, S. et al., J Exp Med 185, 2043-2051 (1997)). Regardless of the α3 domain substitution, the interaction remains suboptimal between mouse CD8 and HLA-A2.1 molecules, since co-crystal analysis has documented that human CD8 also contacts the HLA-A2.1 heavy chain α2 domain (Gao, G. F. et al., Nature 387, 630-634 (1997)). Suboptimal cooperation might also occur in the endoplasmic reticulum where many molecules (TAP, tapasine, ERp 57) assist MHC class I molecule biosynthesis. However, at this stage, the only documented functional difference between these mice and human endoplasmic reticulum molecules, namely the efficient transport by human but not mouse TAP of COOH-terminus positively charged cytosolic peptides (Momburg, F., Neefjes, J. J. & Hammerling, G. J., Curr Opin Immunol 6, 32-37 (1994)), is not relevant for HLA-A2.1 molecules which bind peptides with a hydrophobic C-terminus, since these peptides are transported efficiently by mouse and human TAP. Even though the number of CD8+ T lymphocytes is lower in both single HLA-A2.1-transgenic, H-2 class I-KO mice and in HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO mice, they respond efficiently against HBsAg and, importantly, the latter mice develop antibody, helper and cytolytic cell responses similar to humans. One of the difficulties hampering the design of T-epitope-based vaccines targeting T lymphocytes is HLA class I/class II molecule polymorphism. HLA-A2.1 and HLA-DR1 molecules are expressed by a significant proportion of individuals in human populations (30 to 50% for HLA-A2.1, 6 to 18% for HLA-DR1). Even though the functional clustering of HLA class I molecules in superfamilies is based on significant redundancy of the presented sets of peptides34, individual analysis of the responses elicited by each HLA class I isotypic or allelic variant remains desirable to identify the optimal epitopes they present. This is particularly important to devise a new reagent, such as tetramer (HLA-class I or HLA-class II) to monitor the immune response. For the same reason, it would be helpful to obtain strains of mice co-expressing HLA-A2.1 with other HLA class II molecules, even if the binding of peptides to HLA class II molecules is less restrictive than to class I molecules. Based on the disclosure herein, additional HLA class I-/class II-transgenic, H-2 class I-/class II-KO mice can be constructed for these and other purposes. Whereas HLA-transgenic H-2-KO mice enable a detailed analysis and optimization of the immunogenicity of antigenic peptides with excellent transposability to humans (Rohrlich, P. S. et al., Int Immunol 15, 765-772 (2003); Loirat, D., Lemonnier, F. A. & Michel, M. L., J Immunol 165, 4748-4755 (2000); Scardino, A. et al., Eur J Immunol 31, 3261-3270 (2001)) this is less evident for vaccine adjuvant-formulation studies. This could be due to differences between the two species in the various effectors that are mobilized early in response to an antigenic challenge. Increasing fundamental knowledge of innate immunity might, in the future, lead to a more complete humanization of the mouse immune system. In conclusion, the disclosure herein describes an optimized, humanized transgenic mouse model, whose H-2 class I (mouse β2m) and class II (H-2 IAβb) genes have been deleted and replaced with equivalent human genes HHD (HLA-A*0201), HLA-DRA*0101 and HLA-DRB1*0101. Cellular immunity in the HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO mice is completely restricted by the human HLA molecules, with a complete absence of immune responses restricted by the murine MHC molecules. The absence of competition between murine MHC and human (transgenic) HLA immune responses allows for use of these mice to characterize epitopes in human vaccines that require collaboration between HLA-restricted CD4+ T helper and HLA-restricted CD8+ T cytolytic cells. “HLA” is the human MHC complex, and “H-2” the mouse MHC complex. The human complex comprises three class I a-chain genes, HLA-A, HLA-B, and HLA-C, and three pairs of MHC class II α- and β-chain genes, HLA-DR, -DP, and -DQ. In many haplotypes, the HLA-DR cluster contains an extra β-chain gene whose product can pair with the DRα chain, and so the three sets of genes give rise to four types of MHC class II molecules. In the mouse, the three class I a-chain genes are H-2-L, H-2-D, and H-2-K. The mouse MHC class II genes are H-2-A and H-2-E. It is known in the art that genetic diversity exists between the HLA genes of different individuals as a result of both polymorphic HLA antigens and distinct HLA alleles. Accordingly, embodiments of the invention disclosed herein may substitute one polymorphic HLA antigen for another or one HLA allele for another. Examples of HLA polymorphisms and alleles can be found, for example, at http://www.anthonynolan.org.uk/HIG/data.html and http://www.ebi.ac.uk/imgt/hla, and in Genetic diversity of HLA: Functional and Medical Implication, Dominique Charon (Ed.), EDK Medical and Scientific International Publisher, and The HLA FactsBook, Steven G. E. Marsh, Peter Parham and Linda Barber, AP Academic Press, 2000. A “disrupted” gene is one that has been mutated using homologous recombination or other approaches known in the art. A disrupted gene can be either a hypomorphic allele of the gene or a null allele of the gene. One of skill in the art will recognize that the type of allele to be used can be selected for any particular context. In many embodiments of the invention, a null allele is preferred. “Homologous recombination” is a general approach for targeting mutations to a preselected, desired gene sequence of a cell in order to produce a transgenic animal (Mansour, S. L. et al., Nature 336:348-352 (1988); Capecchi, M. R., Trends Genet. 5:70-76 (1989); Capecchi, M. R., Science 244:1288-1292 (1989); Capecchi, M. R. et al., In: Current Communications in Molecular Biology, Capecchi, M. R. (ed.), Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (1989), pp. 45-52; Frohman, M. A. et al., Cell 56:145-147 (1989)). It is now be feasible to deliberately alter any gene in a mouse (Capecchi, M. R., Trends Genet. 5:70-76 (1989); Frohman, M. A. et al., Cell 56:145-147 (1989)). Gene targeting involves the use of standard recombinant DNA techniques to introduce a desired mutation into a cloned DNA sequence of a chosen locus. That mutation is then transferred through homologous recombination to the genome of a pluripotent, embryo-derived stem (ES) cell. The altered stem cells are microinjected into mouse blastocysts and are incorporated into the developing mouse embryo to ultimately develop into chimeric animals. In some cases, germ line cells of the chimeric animals will be derived from the genetically altered ES cells, and the mutant genotypes can be transmitted through breeding. Gene targeting has been used to produce chimeric and transgenic mice in which an nptII gene has been inserted into the β2-microglobulin locus (Koller, B. H. et al., Proc. Natl. Acad. Sci. (U.S.A.) 86:8932-8935 (1989); Zijlstra, M. et al., Nature 342:435-438 (1989); Zijlstra, M. et al., Nature 344:742-746 (1989); DeChiaba et al., Nature 345:78-80 (1990)). Similar experiments have enabled the production of chimeric and transgenic animals having a c-abI gene which has been disrupted by the insertion of an nptil gene (Schwartzberg, P. L. et al., Science 246:799-803 (1989)). The technique has been used to produce chimeric mice in which the en-2 gene has been disrupted by the insertion of an nptII gene (Joyner, A. L. et al., Nature 338:153-155 (1989)). In order to utilize the “gene targeting” method, the gene of interest must have been previously cloned, and the intron-exon boundaries determined. The method results in the insertion of a marker gene (e.g., an nptil gene) into a translated region of a particular gene of interest. Thus, use of the gene targeting method results in the gross destruction of the gene of interest. Significantly, the use of gene targeting to alter a gene of a cell results in the formation of a gross alteration in the sequence of that gene. The efficiency of gene targeting depends upon a number of variables, and is different from construct to construct. The chimeric or transgenic animal cells of the present invention are prepared by introducing one or more DNA molecules into a cell, which may be a precursor pluripotent cell, such as an ES cell, or equivalent (Robertson, E. J., In: Current Communications in Molecular Biology, Capecchi, M. R. (ed.), Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (1989), pp. 39-44). The term “precursor” is intended to denote only that the pluripotent cell is a precursor to the desired (“transfected”) pluripotent cell, which is prepared in accordance with the teachings of the present invention. The pluripotent (precursor or transfected) cell can be cultured in vivo in a manner known in the art (Evans, M. J. et al., Nature 292:154-156 (1981)) to form a chimeric or transgenic animal. Any ES cell can be used in accordance with the present invention. It is, however, preferred to use primary isolates of ES cells. Such isolates can be obtained directly from embryos, such as the CCE cell line disclosed by Robertson, E. J., In: Current Communications in Molecular Biology, Capecchi, M. R. (ed.), Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (1989), pp. 39-44), or from the clonal isolation of ES cells from the CCE cell line (Schwartzberg, P. A. et al., Science 246:799-803 (1989), which reference is incorporated herein by reference). Such clonal isolation can be accomplished according to the method of E. J. Robertson (In: Teratocarcinomas and Embryonic Stem Cells: A Practical Approach, (E. J. Robertson, Ed.), IRL Press, Oxford, 1987), which reference and method are incorporated herein by reference. The purpose of such clonal propagation is to obtain ES cells, which have a greater efficiency for differentiating into an animal. Clonally selected ES cells are approximately 10-fold more effective in producing transgenic animals than the progenitor cell line CCE. For the purposes of the recombination methods of the present invention, clonal selection provides no advantage. An example of ES cell lines, which have been clonally derived from embryos, are the ES cell lines, AB1 (hprt+) or AB2.1 (hprt−). The ES cells are preferably cultured on stromal cells (such as STO cells (especially SNC4 STO cells) and/or primary embryonic fibroblast cells) as described by E. J. Robertson (In: Teratocarcinomas and Embryonic Stem Cells: A Practical Approach, (E. J. Robertson, Ed., IRL Press, Oxford, 1987, pp 71-112), which reference is incorporated herein by reference. Methods for the production and analysis of chimeric mice are disclosed by Bradley, A. (In: Teratocarcinomas and Embryonic Stem Cells: A Practical Approach, (E. J. Robertson, Ed.), IRL Press, Oxford, 1987, pp 113-151), which reference is incorporated herein by reference. The stromal (and/or fibroblast) cells serve to eliminate the clonal overgrowth of abnormal ES cells. Most preferably, the cells are cultured in the presence of leukocyte inhibitory factor (“Iif”) (Gough, N. M. et al., Reprod. Fertil. Dev. 1:281-288 (1989); Yamamori, Y. et al., Science 246:1412-1416 (1989), both of which references are incorporated herein by reference). Since the gene encoding Iif has been cloned (Gough, N. M. et al., Reprod. Fertil. Dev. 1:281-288 (1989)), it is especially preferred to transform stromal cells with this gene, by means known in the art, and to then culture the ES cells on transformed stromal cells that secrete Iif into the culture medium. As used herein, the term “transgene” refers to a nucleic acid sequence, which is partly or entirely heterologous, i.e., foreign, to the transgenic animal or cell into which it is introduced, or, is homologous to an endogenous gene of the transgenic animal or cell into which it is introduced, but which is designed to be inserted, or is inserted, into the animal's genome in such a way as to alter the genome of the cell into which it is inserted (e.g., it is inserted at a location which differs from that of the natural gene or its insertion results in a knockout). A transgene can be operably linked to one or more transcriptional regulatory sequences and any other nucleic acid, such as introns, that may be necessary for optimal expression of a selected nucleic acid. Exemplary transgenes of the present invention encode, for instance an H-2 polypeptide. Other exemplary transgenes are directed to disrupting one or more HLA genes by homologous recombination with genomic sequences of an HLA gene. A “functional transgene” is one that produces an mRNA transcript, which in turn produces a properly processed protein in at least one cell of the mouse comprising the transgene. One of skill will realize that the diverse set of known transcriptional regulatory elements and sequences directing posttranscriptional processing provide a library of options from which to direct the expression of a transgene is a host mouse. In many embodiments of the invention, expression of an HLA transgene under the control of an H-2 gene regulatory element may be preferred. In some embodiments, the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. An example of an HLA-A2 transgene is one that comprises the HLA-A2 sequence provided in the sequence listing. An example of an HLA-DR1 transgene is one that comprises the HLA-DR1 sequence provided in the sequence listing. In an embodiment, the invention provides a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene. In some embodiments, the mouse has the genotype HLA-A2+HLA-DR1+β2m°IAβ°. In other embodiments the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. The invention also provides isolated transgenic mouse cells. In some cases the cell comprises a disrupted H2 class I gene, a disrupted H2 class II gene, and a functional HLA class I or class II transgene. In others, the cell comprises a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. The HLA class I transgene can be an HLA-A2 transgene and the HLA class II transgene can be an HLA-DR1 transgene. In some cases, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. In an embodiment, the invention provides an isolated transgenic mouse cell deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene. The isolated transgenic mouse cells can have the genotype HLA-A2+HLA-DR1+β2m°IAβ°. The HLA-A2 transgene can comprise the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene can comprise the HLA-DR1 sequence provided in the sequence listing. The isolated transgenic mouse cells of the invention can have the genotype of any mouse of the invention. However, the set of genotypes of the isolated transgenic mouse cells of the invention, and the set of genotypes of the mice of the invention are not necessarily entirely overlapping. The isolated mouse cells of the invention can be obtained from a mouse or mouse embryo. In one embodiment, the mouse or mouse embryo has the same genotype as the cell to be obtained. In another embodiment, the mouse or mouse embryo has a different genotype than the cell to be obtained. After the cell is obtained from the mouse or mouse embryo, a gene of the cell can be disrupted by, for example, homologous recombination. Additionally, a functional transgene can be introduced into the genome of the cell by, for example, transfection. One of skill in the art will recognize that any suitable method known in the art can be applied to modify the genome of the cell to thereby obtain an isolated mouse cell having the desired genotype. An additional object of the invention is an isolated transgenic mouse cell deficient for both H2 class I and class II molecules, wherein the transgenic mouse cell comprises a functional HLA class I transgene and a functional HLA class II transgene. In some embodiments, the transgenic mouse cell has the genotype HLA-A2+HLA-DR1+β2m°IAβ°. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. T cells play a central role in many aspects of acquired immunity, carrying out a variety of regulatory and defensive functions. When some T cells encounter an infected or cancerous cell, they recognize it as foreign and respond by acting as killer cells, killing the host's own cells as part of the cell-mediated immune response. Other T cells, designated helper T cells, respond to perceived foreign antigens by stimulating B cells to produce antibodies, or by suppressing certain aspects of a humoral or cellular immune response. T helper cells (Th) orchestrate much of the immune response via the production of cytokines. Although generally identifiable as bearing the CD4 cell surface marker, these cells are functionally divided into Th1 or Th2 subpopulations according to the profile of cytokines they produce and their effect on other cells of the immune system. The Th1 cells detect invading pathogens or cancerous host cells through a recognition system referred to as the T cell antigen receptor. Termed cellular immunity, Th1-related processes generally involve the activation of non-B cells and are frequently characterized by the production of IFN-γ. Nevertheless, although the Th1 system is primarily independent from the production of humoral antibodies, Th1 cytokines do promote immunoglobulin class switching to the IgG2a isotype. Upon detection of a foreign antigen, most mature Th1 cells direct the release of IL-2, IL-3, IFN-γ, TNF-β, GM-CSF, high levels of TNF-α, MIP-1α, MIP-1β, and RANTES. These cytokines promote delayed-type hypersensitivity and general cell-mediated immunity. IL-2, for instance, is a T cell growth factor that promotes the production of a clone of additional T cells sensitive to the particular antigen that was initially detected. The sensitized T cells attach to and attack cells or pathogens containing the antigen. In contrast, mature Th2 cells tend to promote the secretion of IL-3, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, GM-CSF, and low levels of TNF-α. In addition, the Th2 response promotes humoral immunity by activating B cells, stimulating antibody production and secretion, and inducing class switching to IgA, IgG, and IgE isotypes. As used herein, an “antigen” comprises: 1) at least one HTL epitope, or 2) at least one CTL epitope or, 3) at least one B cell epitope, or 4) at least one HTL epitope and at least one CTL epitope, or 5) at least one HTL epitope and at least one B cell epitope, or 6) at least one CTL epitope and at least one B cell epitope, or 7) at least one HTL epitope and at least one CTL epitope and at least one B cell epitope. A “candidate antigen” is a molecule that is under investigation to determine whether it functions as an antigen. A “humoral immune response” is antibody-mediated specific immunity. An “epitope” is a site on an antigen that is recognized by the immune system. An antibody epitope is a site on an antigen recognized by an antibody. A T-cell epitope is a site on an antigen that binds to an MHC molecule. A TH epitope is one that binds to an MHC class II molecule. A CTL epitope is one that binds to an MHC class I molecule. The antigen can comprise a polypeptide sequence or a polynucleotide sequence, which can comprise RNA, DNA, or both. In one embodiment, the antigen comprises at least one polynucleotide sequence operationally encoding one or more antigenic polypeptides. Used in this context, the word “comprises” intends that at least one antigenic polypeptide is provided by the transcription and/or translation apparatus of a host cell acting upon an exogenous polynucleotide that encodes at least one antigenic polypeptide, as described, for example in U.S. Pat. Nos. 6,194,389 and 6,214,808. Antigens of the invention can be any antigenic molecule. Antigenic molecules include: proteins, lipoproteins, and glycoproteins, including viral, bacterial, parasitic, animal, and fungal proteins such as albumins, tetanus toxoid, diphtheria toxoid, pertussis toxoid, bacterial outer membrane proteins (including meningococcal outer membrane protein), RSV-F protein, malarial derived peptide, B-lactoglobulin B, aprotinin, ovalbumin, lysozyme, and tumor associated antigens such as carcinoembryonic antigen (CEA), CA 15-3, CA 125, CA 19-9, prostrate specific antigen (PSA), and the TM complexes of U.S. Pat. No. 5,478,556, which is incorporated herein by reference in its entirety; carbohydrates, including naturally-occurring and synthetic polysaccharides and other polymers such as ficoll, dextran, carboxymethyl cellulose, agarose, polyacrylamide and other acrylic resins, poly (lactide-co-glycolide), polyvinyl alcohol, partially hydrolyzed polyvinyl acetate, polyvinylpryrolidine, Group B Steptococcal and Pneumococcal capsular polysaccharides (including type III), Pseudomonas aeruginosa mucoexopolysaccharide, and capsular polysaccharides (including fisher type I), and Haemophilus influenzae polysaccharides (including PRP); haptens, and other moieties comprising low molecular weight molecules, such as TNP, saccharides, oligosaccharides, polysaccharides, peptides, toxins, drugs, chemicals, and allergens; and haptens and antigens derived from bacteria, rickettsiae, fungi, viruses, parasites, including Diphtheria, Pertussis, Tetanus, H. influenzae, S. pneumoniae, E. Coli, Klebsiella, S. aureus, S. epidermidis, N. meningiditis, Polio, Mumps, measles, rubella, Respiratory Syncytial Virus, Rabies, Ebola, Anthrax, Listeria, Hepatitis A, B, C, Human Immunodeficiency Virus I and 11, Herpes simplex types 1 and 2, CMV, EBV, Varicella Zoster, Malaria, Tuberculosis, Candida albicans, and other candida, Pneumocystis caringi, Mycoplasma, Influenzae virus A and B, Adenovirus, Group A streptococcus, Group B streptococcus, Pseudomonas aeryinosa, Rhinovirus, Leishmania, Parainfluenzae, types 1, 2 and 3, Coronaviruses, Salmonella, Shigella, Rotavirus, Toxoplasma, Enterovirusses, and Chlamydia trachomatis and pneumoniae. As used herein, a pharmaceutical composition or vaccine comprises at least one immunological composition, which can be dissolved, suspended, or otherwise associated with a pharmaceutically acceptable carrier or vehicle. Any pharmaceutically acceptable carrier can be employed for administration of the composition. Suitable pharmaceutical carriers are described in Remington's Pharmaceutical Sciences, 18th Edition (A. Gennaro, ed., 1990) Mack Pub., Easton, Pa., which is incorporated herein by reference in its entirety. Carriers can be sterile liquids, such as water, polyethylene glycol, dimethyl sulfoxide (DMSO), oils, including petroleum oil, animal oil, vegetable oil, peanut oil, soybean oil, mineral oil, sesame oil, and the like. Carriers can be in the form of mists, sprays, powders, waxes, creams, suppositories, implants, salves, ointments, patches, poultices, films, or cosmetic preparations. Proper formulation of the pharmaceutical composition or vaccine is dependent on the route of administration chosen. For example, with intravenous administration by bolus injection or continuous infusion, the compositions are preferably water soluble, and saline is a preferred carrier. For transcutaneous, intranasal, oral, gastric, intravaginal, intrarectal, or other transmucosal administration, penetrants appropriate to the barrier to be permeated can be included in the formulation and are known in the art. For oral administration, the active ingredient can be combined with carriers suitable for inclusion into tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions, and the like. Time-sensitive delivery systems are also applicable for the administration of the compositions of the invention. Representative systems include polymer base systems, such as poly(lactide-glycoside), copolyoxalates, polycaprolactones, polyesteramides, polyorthoesters, polyhydroxybutyric acid and polyanhydrides. These and like polymers can be formulated into microcapsules according to methods known in the art, for example, as taught in U.S. Pat. No. 5,075,109, which is incorporated herein by reference in its entirety. Alternative delivery systems appropriate for the administration of the disclosed immunostimulatory compounds of the invention include those disclosed in U.S. Pat. Nos. 6,194,389, 6,024,983 5,817,637, 6,228,621, 5,804,212, 5,709,879, 5,703,055, 5,643,605, 5,643,574, 5,580,563, 5,239,660, 5,204,253, 4,748,043, 4,667,014, 4,452,775, 3,854,480, and 3,832,252 (each of which is incorporated herein by reference in its entirety). Aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable or aerosol solutions. For administration by aerosol, as by pressurized spray or nebulizer, suitable propellants can be added as understood by those familiar with the art. The immunological composition can also be formulated with solubilizing agents; emulsifiers; stabilizers; dispersants; flavorants; adjuvants; carriers; topical anesthetics, such as lidocaine, xylocaine, and the like; antibiotics; and known or suspected anti-viral, anti-fungal, anti-parasitic, or anti-tumor compounds. An “adjuvant” is a composition that promotes or enhances an immune response to a target antigen. One of skill in the art can select an appropriate adjuvant for use in practicing the present invention in view of the disclosure herein. The present invention encompasses methods of treating a patient in need of immune stimulation by administering a composition comprising one or more antigens of the invention. As used herein, treatment encompasses corrective, restorative, ameliorative, and preventive methods relating to any disease, condition, abnormality, or symptom. Treatment further encompasses the elicitation or suppression of an immune response in an experimental animal or ex vivo. Thus, treatment comprises administering an immunostimulatory amount of any of the immunostimulatory compositions of the invention by any method familiar to those of ordinary skill in the art, commonly including oral and intranasal routes, and intravenous, intramuscular, and subcutaneous injections, but also encompassing, intraperitoneal, intracorporeal, intra-articular, intraventricular, intrathecal, topical, tonsillar, mucosal, transdermal, intravaginal administration and by gavage. As is recognized by the skilled practitioner, choosing an appropriate administration method may contribute to the efficacy of a treatment, and local administration may be preferred for some applications. Acceptable routes of local administration include subcutaneous, intradermal, intraperitoneal, intravitreal, inhalation or lavage, oral, intranasal, and directed injection into a predetermined tissue, organ, joint, tumor, or cell mass. For example, mucosal application or injection into mucosal lymph nodes or Peyer's patches may promote a humoral immune response with substantial IgA class switching. Alternatively, targeted injection into a lesion, focus, or affected body site may be applicable for the treatment of solid tumors, localized infections, or other situs requiring immune stimulation. Alternatively, cells of the immune system (e.g., T cells, B cells, NK cells, or oligodendrocytes) can be removed from a host and treated in vitro. The treated cells can be further cultured or reintroduced to a patient (or to a heterologous host) to provide immune stimulation to the patient or host. For example, bone marrow cells can be aspirated from a patient and treated with an HDR to stimulate global or specific immunity. High-dose radiation, or comparable treatments, can then be used to destroy the remaining immune cells in the patient. Upon re-implantation, the autologous stimulated cells will restore normal immune function in the patient. Alternatively, NK and/or T cells isolated from a patient suffering from cancer may be exposed in vitro to one or more antigens specific to the patient's cancer. Upon re-implantation into the patient, the antigen-stimulated cells will deploy a vigorous cellular immune response against the cancerous cells. An immunostimulatory (efficacious) amount refers to that amount of vaccine that is able to stimulate an immune response in a patient, which is sufficient to prevent, ameliorate, or otherwise treat a pathogenic challenge, allergy, or immunologic abnormality or condition. An immunostimulatory amount is that amount, which provides a measurable increase in a humoral or cellular immune response to at least one epitope of the antigen as compared to the response obtained if the antigen is administered to the patient without prior treatment with the vaccine. Thus, for example, an immunostimulatory amount refers to that amount of an antigen-containing composition that is able to promote the production of antibodies directed against an antigenic epitope of interest or stimulate a detectable protective effect against a pathogenic or allergenic challenge or to promote a protective CTL response against an antigenic epitope of interest. Treatment with an immunostimulatory amount of an antigen-containing composition of the invention comprises effecting any directly, indirectly, or statistically observable or measurable increase or other desired change in the immune response in a host, specifically including an ex vivo tissue culture host, comprising at least one cell of the immune system or cell line derived therefrom. Host cells can be derived from human or animal peripheral blood, lymph nodes or the like. Preferred tissue culture hosts include freshly isolated T cells, B cells, macrophages, oligodendrocytes, NK cells, and monocytes, each of which can be isolated or purified using standard techniques. Observable or measurable responses include, B or T cell proliferation or activation; increased antibody secretion; isotype switching; increased cytokine release, particularly the increased release of one or more of IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12, IL-13, GM-CSF, IFN-γ, TNF-α, TNF-β, GM-CSF, MIP-1α, MIP-1β, or RANTES; increased antibody titer or avidity against a specific antigen; reduced morbidity or mortality rates associated with a pathogenic infection; promoting, inducing, maintaining, or reinforcing viral latency; suppressing or otherwise ameliorating the growth, metastasis, or effects of malignant and non-malignant tumors; and providing prophylactic protection from a disease or the effects of a disease. Where the suppression of an immunological response is desired, for example, in the treatment of autoimmune disease or allergy, an effective amount also encompasses that amount sufficient to effect a measurable or observable decrease in a response associated with the condition or pathology to be treated. The amount of an antigen-containing composition to be administered and the frequency of administration can be determined empirically and will take into consideration the age and size of the patient being treated, and the condition or disease to be addressed. An appropriate dose is within the range of 0.01 μg to 100 μg per inoculum, but higher and lower amounts may also be indicated. Secondary booster immunizations can be given at intervals ranging from one week to many months later. The following examples demonstrate certain embodiments of the invention. One of ordinary skill in the art will recognize the numerous modifications and variations that may be performed without altering the spirit or scope of the present invention. Such modifications and variations are believed to be encompassed within the scope of the invention. The examples do not in any way limit the invention. EXAMPLES The following experimental techniques and reagents were used to demonstrate certain nonlimiting embodiments of the invention. Transgenic Mice The HLA-DR1-transgenic H-2 class II-KO (IA βb°) mice were obtained at the Institut Pasteur of Lille by crossing HLA-DR1-transgenic mice (Altmann, D. M. et al., J Exp Med 181, 867-875 (1995)) with H-2 class II-KO (IA βb°) mice (Rohrlich, P. S. et al., Int Immunol 15, 765-772 (2003)). The HLA-A2.1-transgenic mice, expressing a chimeric monochain (HHD molecule: α1-α2 domains of HLA-A2.1, α3 to cytoplasmic domains of H-2 Db, linked at its N-terminus to the C terminus of human β2m by a 15 amino-acid peptide linker) were created (Pascolo, S. et al., J Exp Med 185, 2043-2051 (1997)). HLA-A2.1 (HHD)-transgenic H-2 class I-KO and HLA-DR1-transgenic H-2 class II-KO (IA βb°) mice were intercrossed and progenies screened until HLA-A2.1±/HLA-DR1± double transgenic H-2-class I (β2m0)-/class II (IAβ0)-KO animals were obtained and used for the experiments described herein. HLA-A2.1± single transgenic H-2-class I (β2m0)-/class II (IAβ0)-KO mice were used as controls in the protection assays. Mice were bred in the animal facilities at the Institut Pasteur, Paris; all protocols were reviewed by the Institut Pasteur competent authority for compliance with the French and European regulations on Animal Welfare and with Public Health Service recommendations. Genotyping The HLA-DRB1*0101, HLA-DRA*0101 and HLA-A*0201 transgenes were detected by PCR. Tail-DNA was extracted after overnight incubation at 56° C. in 100 mM NaCl, 50 mM Tris-HCl pH 7.2, 100 mM EDTA, 1% SDS and 0.5 mg/ml proteinase K, followed by the addition of 250 μl of saturated NaCl solution and isopropanol precipitation. The samples were washed (3×) in 70% ethanol and resuspended in 150 μl of 10 mM Tris-HCl, 1 mM EDTA pH 8. PCR conditions were: 1.5 mM MgCl2, 1.25 U of Taq Polymerase, buffer supplied by the manufacturer (InVitrogen, Carlsbad, Calif.), 1 cycle (7 min, 94° C.), 40 cycles (30 sec, 94° C.; 30 sec, 60° C.; 1 min, 72° C.), 1 cycle (4 min, 72° C.), using as forward and reverse primers, for HHD: 5′CAT TGA GAC AGA GCG CTT GGC ACA GAA GCA G 3′ and 5′GGA TGA CGT GAG TM ACC TGA ATC UTT GGA GTA CGC 3′, for HLA-DRB1*0101: 5′ TTC TTC AAC GGG ACG GAG CGG GTG 3′ and 5′ CTG CAC TGT GM GCT CTC ACC MC 3′, and for HLA-DRA*0101: 5′ CTC CAA GCC CTC TCC CAG AG 3′ and 5′ ATG TGC CTT ACA GAG GCC CC 3′. FACS Analysis Cytofluorimetry studies were performed on red-blood cell-depleted, Lympholyte M-purified (Tebu-bio, Le Perray en Yvelines, France) splenocytes using FITC-conjugated W6/32 (anti-HLA-ABC, Sigma, St Louis, Mo.) and biotinilated anti-28-8-6S (anti-H-2 Kb/Db, BD Biosciences, San Diego, Calif.) m.Ab. CD4+ and CD8+ T lymphocytes were stained using PE-labeled CT-CD4 anti-mouse CD4 (CALTAG, South San Francisco, Calif.) and FITC-labeled 53-6.7 anti-mouse CD8 m.Ab (BD Biosciences). Analysis of MHC class II molecule expression was performed on B220+ B lymphocytes positively selected on MS columns (Miltenyi Biotec, Bergisch Gladbach, Germany). Following saturation of Fc receptors with 2.4G2 m.Ab, expression of HLA-DR1 and H-2 IAb was analyzed using FITC-labeled L243 (anti-HLA-DR) and PE-labeled AF6-120.1 (anti-H-2 IAβb) m.Ab (BD Biosciences). Paraformaldehyde fixed cells were analyzed with a FACSCalibur (Becton Dickinson, Bedford, Mass.). Immunoscope Analyses CD4+ and CD8+ T cells from naive mice were positively selected on Auto-Macs (Miltenyi Biotec), RNA prepared using RNA Easy Kit (Qiagen, Hilden, Germany) and used for cDNA synthesis. The cDNA was PCR-amplified using forward primers specific for each BV segment family and a reverse primer shared by the two BC segments. PCR-products were subjected to a run-off-elongation with internal BC FAM-tagged primer. The run-off products were loaded on a 6% acrylamide/8 M urea gel for separation (7 h, 35 W) with a 373A DNA sequencer (Perkin Elmer Applied Biosystem, Foster City, Calif.). Data were analyzed using immunoscope software (Pannetier, C. et al., Proc Natl Acad Sci USA 90, 4319-4323 (1993)). Peptides The HLA-A2 binding peptides HBsAg348-357 GLSPTVWLSV and HBsAg335-343 WLSLLVPFV, the H-2 Kb binding peptide HBsAg371-378 ILSPFLPL, the HLA-DR1 binding peptide HBsAg180-195 QAGFFLLTRILTIPQS, the H-2 IAb binding peptide HBsAg126-138 RGLYFPAGGSSSG and the preS2 peptide HBsAg109-134 MQWNSTTFHQTLQDPRVRGLYFPAGG were synthesized by Neosystem (Strasbourg, France) and dissolved in PBS-10% DMSO at a concentration of 1 mg/ml. The numbering of the amino acid sequence of peptides starts from the first methionine of the HBV ayw subtype preS1 domain. Immunization with DNA Encoding the S2-S Proteins of HBV The pCMV-S2.S plasmid vector (Michel, M. L. et al., Proc Natl Acad Sci USA 92, 5307-5311 (1995)) coding for the preS2 and the S HBV surface antigens expressed under the control of the human CMV immediate early gene promotor was purified on Plasmid Giga Kit columns under endotoxin free conditions (Qiagen). Anesthesized mice were injected (50 μg each side) into regenerating tibialis anterior muscles, as previously described (Davis, H. L., Michel, M. L. & Whalen, R. G., Hum Mol Genet 2, 1847-1851 (1993)). T Cell Proliferation Assay Twelve days after the last immunization, red-blood cell-depleted, Ficoll-purified splenocytes (5.106 cells/25 cm2 culture flask (Techno Plastic Products (TPP), Trasadingen, Switzerland)) were co-cultured with peptide-pulsed (20 μg/ml), γ-irradiated (180 Gy) LPS-blasts (5.106 cells/ culture flask) in RPMI medium supplemented with 10% FCS, 10 mM HEPES, 1 mM sodium pyruvate, 5×10−5 M 2-mercaptoethanol, 100 I.U/ml penicillin and 100 μg streptomycin, as described (Loirat, D., Lemonnier, F. A. & Michel, M. L., J Immunol 165, 4748-4755 (2000)). On day 7, for proliferation assays, cells were plated (5×105 cells/well of flat bottomed 96 well microplates, (TPP)) with peptide-pulsed irradiated LPS-Blasts (2×105 cells/well) for 72 h in complete RPMI medium supplemented with 3% FCS. Cells were pulsed for the final 16 h with 1 μCi of (3H)-thymidine per well before being harvested on filtermates with a TOMTEC collector (Perkin Elmer Applied Biosystem), and incorporated radioactivity was measured on a micro-β counter (Perkin Elmer Applied Biosystem). Results are given as stimulation index (SI)=cpm with specific peptide/cpm with irrelevant peptide. Measurement of CTL Activity Cytotoxicity assays were performed on the same immune splenocyte populations as the proliferation assays. Responder cells (5.106 cells/25 cm2 culture flask, TPP) and stimulating peptide-pulsed (20 μg/ml), γ-irradiated (180 Gy) LPS-blasts (5.106 cells/ culture flask) were co-cultured for 7 days in the same supplemented RPMI medium as for proliferation assays. Cytolytic activity was tested in a standard 4 h 51Cr assay against RMA-S HHD target cells pulsed with 10 μg/ml of the experimental or control peptides. Specific lysis, in %, was calculated in duplicates, according to: [experimental−spontaneous release]/[maximal−spontaneous release]×100, substracting the non-specific lysis observed with the control peptide. Measurement of in vivo Antibody Production At various times before and after DNA injection, blood was collected from mice by retrobulbar puncture with heparinized glass pipettes, and sera recovered by centrifugation were assayed for anti-HBs and anti-preS2 by specific ELISA. Purified recombinant particles containing HBV small S protein (1 ug/ml) or preS2 (120-145) synthetic peptide (1 ug/ml) were used as the solid phase. After blocking with PBST (PBS containing 0.1% Tween 20) supplemented with 10% FCS, serial dilutions were added. After extensive washing, the bound antibodies were detected with anti mouse Ig (total IgG) labeled with horseradish peroxidase (Amersham, Little Chalfont, UK). Antibody titers were determined by the serial end-point dilution method. Mouse sera were tested individually, and titers were the mean of at least three determinations. Serum dilutions below 1/100 were considered negative. Antibody Titration Sera from immunized mice were individually assayed by ELISA (Michel, M. L. et al., Proc Natl Acad Sci USA 92, 5307-5311 (1995)) on either purified HBV middle and small proteins or preS2 synthetic HBs109-134. peptide, After blocking with PBS 1× supplemented with 0.1% Tween 20, 10% FCS and washings (×3), bound antibodies were detected with horseradish peroxidase-labeled anti-mouse IgG (Amersham, Little Chalfont, UK). Antibody titers (means of at least 3 determinations) were determined by the serial end-point dilution method. Titers below 1/100 were considered negative. Vaccinia Challenge and Plaque Assay DNA-injected mice were challenged intraperitoneally 12 days post last injection with 107 PFU of recombinant vaccinia virus (Western Reserve strain) expressing either the HbsAg (Smith, G. L., Mackett, M. & Moss, B., Nature 302, 490-495 (1983)) or the HBx protein (Schek, N., Bartenschlager, R., Kuhn, C. & Schaller, H., Oncogene 6, 1735-1744. (1991)) kindly provided, respectively, by Dr B. Moss and Dr H. Schaller. Four days later, ovaries were assayed for rVV titers by plaque assay on BHK 21 cells (Buller, R. M. & Wallace, G. D., Lab Anim Sci 35, 473-476 (1985). Example 1 Cell Surface Expression of MHC Molecules Cell surface expression of the HLA-A2.1, H-2 Kb/Db, HLA-DR1, and H-2 IAb molecules was evaluated on splenocytes by flow cytometry. As illustrated in FIG. 1a, a similar level of HLA-A2.1 expression was observed in HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice and HLA-A2.1-transgenic, H-2 class I-KO mice, while HLA-A2.1 was absent and H-2 Kb/Db expressed exclusively in HLA-DR1-transgenic, H-2 class II-KO mice. Cell surface expression of HLA-DR1 and H-2 IAb was measured on B220+-enriched B cells. As shown in FIG. 1b, a similar level of HLA-DR1 expression was observed in HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice and HLA-DR1-transgenic, H-2 class II-KO mice, whereas no expression was detected in HLA-A2.1-transgenic, H-2 class I-KO mice. Cell surface expression of the transgenic molecules (especially HLA-DR1) was, however, lower than the expression of endogenous H-2 class I and class II molecules. Example 2 Peripheral CD4+ and CD8+ T Cells CD4+ and CD8+ splenic T cell numbers were determined by immunostaining and flow cytometry analysis as illustrated in FIG. 2a. CD4+ T cells represented 13-14% of the splenocyte population in both HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice and HLA-DR1-transgenic, H-2 class II-KO mice. In contrast, only 2-3% of the cells were CD4+ in H-2 class II-KO mice (data not shown), in agreement with the initial report on mice lacking MHC class II molecules (Cosgrove, D. et al., Cell 66, 1051-1066 (1991)). As expected, expression of transgenic HLA-A2.1 molecules led to an increase in the size of the peripheral CD8+ T cell population, which reached 2-3% of the total splenocytes in both HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice and HLA-A2.1-transgenic, H-2 class I-KO mice, compared to 0.6-1% in the β2 microglobulin (β2m)-KO MHC class I-deficient mice (Pascolo, S. et al., J Exp Med 185, 2043-2051 (1997)). The results presented in Examples 1 and 2 show that: (1) In the HLA-A2+HLA-DR1+β2m°IAβ° mouse, the expression of HLA-A2 molecules, the absence of expression of H2-Kb molecules, the number of CD8+ peripheral T-lymphocytes, and the diversity of the CD8+ T repertoire are generally comparable to the HLA-A2+β2m° mouse; (2) In the HLA-A2+HLA-DR1+β2m°IAβ° mouse, the expression of HLA-DR1 molecules, the absence of expression of H2-IAb molecules, the number of CD4+ T-lymphocytes, and the diversity of the CD4+ repertoire are generally comparable to the HLA-DR1+IAβ° mouse; and (3) The HLA-A2+HLA-DR1+β2m°IAβ° mouse has all the characteristic advantages found in HLA-A2+β2m° mice, and the HLA-DR1+IAβ° mice. Example 3 TCR BV Segment Usage As the presence of a single MHC class I and single MHC class II molecule could diminish the size and diversity of the TCR repertoire, the expression of the various BV families and the CDR3 length diversity was studied as previously described (Cochet, M. et al., Eur J Immunol 22, 2639-2647 (1992)) by the RT-PCR-based immunoscope technique, on purified splenic CD4+ or CD8+ T cells. Peaks of significant magnitude with a Gaussian-like distribution were observed for most BV families (15 out of the 20 analyzed) in both CD8+ (FIG. 2b) and CD4+ (FIG. 2c) populations of T cells. Such profiles observed on peripheral T lymphocytes are typical of functionally rearranged BV segments with a 3 nucleotide length variation of the CDR3 subregions from one peak to the next (Cochet, M. et al., Eur J Immunol 22, 2639-2647 (1992)). Absence of expansion (or profoundly altered profile) as observed for BV 5.3 and 17 were expected since these two BV segments are pseudogenes in C57BL/6 mice (Wade, T., Bill, J., Marrack, P. C., Palmer, E. & Kappler, J. W., J Immunol 141, 2165-2167 (1988)); Chou, H. S. et al., Proc Natl Acad Sci USA 84, 1992-1996 (1987). However, the altered profiles observed for BV5.1, 5.2 and 11 segments were due to a small subpopulation of corresponding BV-expressing T cells (they represent lower than 5% in C57BL/6 mice, and around 2% in HLA-DR1-transgenic H-2 class II-KO mice) (data not shown). Other than these instances, both CD4+ and CD8+ T cells in HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice display, respectively, a pattern of TCR BV chain usage and CDR3 diversity, which is similar to that of non-transgenic C57BL/6 mice. Example 4 Functional Characterization HLA-A2+HLA-DR1+β2m°IAβ° mice immunized with Ag HBs (hepatitis B envelope protein) were analyzed. FIG. 5 shows the specific humoral response, as indicated by the production of HBs S2 antibodies. FIG. 6 shows the specific DR1-restricted CD4+ T proliferation response of HBs348-357. And FIG. 7 shows the specific HLA-A2-restricted CD8+ cytolytic T response of the HBs348-357 or HBs335-343. These results show that the HLA-A2+HLA-DR1+β2m°IAβ° mouse allows for simultaneous analysis of the specific humoral response, of the Ag-specific HLA-DR1-restricted response of CD4+ T helper cells, and of the cytolitic response of Ag-specific HLA-A2-restricted CD8+ T cells in an immunized individual. Additional data obtained from these mice is provided in the following Tables 1-3. TABLE 1 Proliferative responses of T CD4+ against HBV virus envelope HLA-DR1 epitopes from HLA-A2+ DR1+H-2 Cl-Cll- transgenic mice injected with pcmv S2-S Responder/ Stimu- tested lation position Amino Acid sequence mice index 109-134 MQWNSTTFHQTLQDPRVRGLY (12/12) 3-4 FPAGG 200-214 TSLNFLGGTTVCLGQ (6/12) 3-4 16/31 QAGFFLLTRILTIPQS (12/12) 3-6 337/357 SLLVPFVQWFVGLSPTVWLSV (5/12) 4-5 TABLE 2 Cytolytic response to HLA-A2+DR1+H-2 Cl- Cll-transgenic mice injected with pcmv S2-S Amino Acid Responder/ position sequence tested mice Maximal lysis 348-357 GLSPTVWLS (12/12) 20-70% 335-343 WLSLLVPVF (4/12) 30% TABLE 3 Anti-PreS2 Antibody response anti of HLA-A2+ DR1+H-2 Cl-Cll transgenic mice injected with pcmv S2-S Responder/ position Amino Acid sequence tested mice preS2 MQWNSTTFHQTLQDPRVRGLYFPAGG (9/12) Example 5 Immune Response to HBsAg-DNA-Vaccine To evaluate the immunological potential of HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice, and to compare their humoral, CD4+ and CD8+ T cell responses to those of humans, mice were immunized with an HBsAg-DNA plasmid. This plasmid encodes two hepatitis B virus envelope proteins (preS2/S middle and S/small) that self-assemble in particles carrying hepatitis B surface antigen. The currently used vaccine against hepatitis B comprises these two proteins. As illustrated in FIG. 3a for a representative mouse, HBsAg-specific antibodies were first detected at day 12 after injection of the HBsAg-DNA-vaccine (FIG. 3a, upper panel), and the titer of these antibodies increased up to day 24 (12 days after the second DNA immunization, data non shown). This early antibody response was specific for the preS2-B cell epitope (HBs109-134) carried by the middle HBV envelope protein and for HBsAg particles, in agreement with a similar response reported in HBsAg-DNA-immunized mice (Michel, M. L. et al., Proc Natl Acad Sci USA 92, 5307-5311 (1995)) and in HBsAg vaccinated humans (Moulia-Pelat, J. P. et al., Vaccine 12, 499-502 (1994)). The CD8+ CTL response to HBsAg was examined to determine whether the CD8+ T cells in the periphery of the HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mouse were functionally restricted by the transgenic human class I molecules. In HBV-infected HLA-A2.1+ humans, the immunodominant HLA-A2.1-restricted HBsAg-specific CTL response is directed at the HBsAg348-357 (Maini, M. K. et al., Gastroenterology 117, 1386-1396 (1999)) and at the HBsAg335-343 (Nayersina, R. et al., J Immunol 150, 4659-4671 (1993)) peptide (i.e., a multi-epitopic response is observed). In C57BL/6 mice, the H-2 Kb-restricted HBsAg-specific CTL response is directed at the HBsAg371-378 peptide (Schirmbeck, R., Wild, J. & Reimann, J., Eur J Immunol 28, 4149-4161 (1998)). To evaluate whether the humanized mouse may respond as humans, splenic T cells were restimulated for 7 days, as described herein, with either relevant (HBsAg348-357, HLA-A2.1-restricted), or control (HBsAg371-378, H-2 Kb-restricted; MAGE-3271-279, HLA-A2.1-restricted) peptide. FIG. 3a (middle panel) shows that HBsAg-DNA-immunization elicited a strong HBsAg348-357-specific CTL response, but no response to either HBsAg371-378 or the MAGE-3271-279 peptide. To determine whether the CD4+ T cells in the periphery of this HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mouse may be functionally restricted by the transgenic human class II molecules, the CD4+ T cell response to the HBsAg protein was examined. In HBsAg-vaccinated or HBV-infected HLA-DR1+ humans, an immunodominant HLA-DR1-restricted HBsAg-specific CD4+ T cell response is directed at the HBsAg180-195 peptide (Mm, W. P. et al., Hum Immunol 46, 93-99 (1996)). In C57BL/6 mice, the H-2 IAb-restricted HBsAg-specific CD4+ T cell response is directed at the HBsAg126-138 peptide (Milich, D. R., Semin Liver Dis 11, 93-112(1991)). To compare the humanized mouse with humans and wild-type mice, splenic T cells were restimulated in vitro with either relevant (HBsAg180-195, HLA-DR1-restricted) or control (HBsAg126-138, H-2 IAb-restricted; HIV 1 Gag263-278, HLA-DR1-restricted) peptides. FIG. 3a (lower panel) shows a strong proliferative response directed against the HLA-DR1-restricted HBsAg180-195 peptide, while the H-2 IA-restricted peptide was not efficient at stimulating a response, as expected. Similarly, no response was induced by the HIV 1 Gag263-278 peptide. Moreover, an additional in vitro recall with the HBsAg180-195 peptide increased several-fold the specific proliferative index (data not shown). Having documented in a first HBsAg-DNA-immunized HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO mouse the development and the specificity of the HBsAg-specific antibody, proliferative and cytolytic T cell responses, 6 additional HBsAg-DNA-immunized and 6 naive control HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-KO mice were also tested individually for the same three responses. As illustrated in FIG. 3b, the three reponses were simultaneously documented in the 6 immunized animals tested and not in control naive mice. Interestingly, 2 immunized mice were able to develop CTL responses against both HBsAg348-357 and HBsAg335-343 HLA-A2.1 restricted peptides (FIG. 3b, middle panel). Example 6 Protection Assays The above examples document the induction of HBsAg-specific humoral, CD4+ and CD8+ T cell responses in HLA-A2.1-/HLA-DR1-transgenic, H-2 class I-/class II-KO mice, and show that they are directed at the same immunodominant epitopes as those of naturally-infected or HBsAg-vaccinated humans. This example tested whether these responses conferred protection to vaccinated animals. Since mice are not permissive to HBV, a HBsAg-recombinant vaccinia virus (rVV-HBsAg) was used for these experiments. Mice were immunized twice intramuscularly with 100 μg of HBsAg-DNA. Twelve days after the last immunization, mice were challenged intraperitoneally with 107 PFU of rVV-HBsAg. Four days later, virus titers were determined according to published methods and recorded as rVV PFU/ovary (Buller, R. M. & Wallace, G. D., Lab Anim Sci 35, 473-476 (1985)). The results are illustrated in FIG. 4. Naive animals that had not been immunized with HBsAg-DNA showed evidence of rVV-HBsAg replication after challenge. In contrast, the virus titers in mice immunized with HBsAg-DNA were more than 4 orders of magnitude lower. These results strongly suggest that vaccination with HBsAg-DNA induced protective HBsAg-specific immune responses that controlled the infection with rVV-HBsAg. The specificity of the protection conferred by HBsAg-DNA-vaccination was documented by challenging HBsAg-DNA-immunized mice with another HBx-recombinant VV (encoding hepatitis B x protein). No reduction of rVV-HBx replication was observed in HBsAg-DNA-immunized mice compared to unimmunized controls. Example 7 HLA-DR1-Restricted CD4+ T Cells Are Critical for Antibody and CTL Responses and Protection Against Viral Infection To evaluate whether HLA-DR1-restricted T helper lymphocytes contribute to antibody and CTL responses in the humanized mice, the immune response and the efficiency of viral infection were compared in single (HLA-A2.1) and double (HLA-A2.1/HLA-DR1) transgenic, H-2 class I-/class II-KO mice. As shown in Table 4, a potent HBsAg348-357-specific CTL response was observed in HLA-A2.1-/HLA-DR1-double transgenic, H-2 class I-/class II-KO mice, but not in HLA-A2.1-single transgenic H-2 class I-/class II-KO mice. Furthermore, anti-HBs antibodies could not be detected in HBsAg-DNA-vaccinated HLA-A2.1- single transgenic H-2 class I-/class II-KO mice. As a consequence, HBsAg-DNA-immunized HLA-A2.1- single transgenic H-2 class I-/class II-KO mice were not protected against rVV-HBsAg infection. TABLE 4 Table 4 Antibody, cytolytic, and proliferative responses of HBsAg- DNA- immunized mice, and protection against rVV-HBsAg-challenge Specific Lysis Proliferation Anti- rVV-HBsAg (%) (SI) body PFU/ovary Mice 348-357 335-343 179-194 Titer (log10) A 1 0 0 1 0 2.5 · 108 2 0 0 1 0 2.5 · 108 3 0 0 1 0 108 4 0 0 1 0 2.5 · 108 5 0 0 1 0 108 6 0 0 1 0 1.5 · 108 B 1 30 15 4.7 2000 104 2 14 0 3.9 3000 3 · 103 3 30 11 4 7500 4 · 103 4 5 0 2.5 6500 7.5 · 103 5 50 30 6.3 13000 7.5 · 102 6 40 18 4 16000 5 · 102 7 6 7 2.9 1500 2 · 104 8 5 5 3 2500 1.5 · 104 9 24 36 4.5 3000 <102 10 23 14 5 15000 5 · 103 C 1 0 0 1 0 108 2 0 0 1 0 2 · 108 3 0 0 1 0 1.5 · 108 4 0 0 1 0 108 5 0 0 1 0 2.5 · 108 6 0 0 1 0 108 Naive HLA-A2.1-/HLA-DR1-double transgenic H-2 class I-/class II-KO mice (A 1-6), HBsAg-DNA-immunized HLA-A2.1-HLA-DR1-double transgenic H-2 class I-/class II-KO mice (B 1-10) and HBsAg-DNA-immunized HLA-A2.1-single transgenic H-2 class I-/class II-KO mice (C 1-6) were challenged intraperitoneally with 107 PFU of rVV-HBsAg. Four days later, PFU per ovary, cytolytic and proliferative splenic T cell responses and serum antibody titers were assessed individually using either HBsAg348-357, (immunodominant) or HBsAg335-343 (subdominant), HLA-A2.1-restricted peptides-loaded RMAS-HHD target cells (E/T ratio 30/1) for cytolytic assays, HBsAg179-194 HLA-DR1-restricted peptide for proliferation assays and preS2109-134 peptide for the determination of antibody (IgG) titers. The entire contents of all references, patents and published patent applications cited throughout this application are herein incorporated by reference in their entirety.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Many vaccines are currently being developed for human cancer immunotherapy and for treatment of infectious diseases, such as malaria, AIDS, hepatitis C virus, and SARS. Given the rapidity with which new emerging pathogens can appear, it is important to improve animal models that could be used to evaluate vaccination strategies and the protective capacity of different epitopes quickly and reliably. Furthermore, in vivo studies are already required to assess crucial variables of vaccine behavior that are not easily evaluated or impossible to measure in vitro, such as vaccine immunogenicity, vaccine formulation, route of administration, tissue distribution, and involvement of primary and secondary lymphoid organs. Because of their simplicity and flexibility, small animals, such as mice represent an attractive alternative to more cumbersome and expensive model systems, such as nonhuman primates, at least for initial vaccine development studies. The moderate efficacy observed in several clinical trials of vaccines, which were found to be protective in wild-type animal studies (McMichael, A. J. & Hanke, T. Nat Med 9, 874-880 (2003)), may be partly explained by the different influence that human and animal MHC have on the outcome of the immune response, since animal MHC and human HLA molecules do not present the same optimal epitopes (Rotzschke, O. et al. Nature 348, 252-254 (1990)). Thus, despite some limitations, transgenic mice expressing human HLA should represent a useful improvement over wild-type mice as a preclinical model for testing vaccine candidates, evaluating the potential risk that the vaccines could induce autoimmune disorders, and devising better therapeutic strategies based on the human restriction element. Cytotoxic T Cells Cytotoxic T cells (CTL) play a crucial role in the eradication of infectious diseases and in some cases, cancer (P. Aichele, H. Hengartner, R. M. Zinkernagel and M. Schulz, J Exp Med 171 (1990), p.1815; L. BenMohamed, H. Gras-Masse, A. Tartar, P. Daubersies, K Brahimi, M. Bossus, A. Thomas and P. Druhile, Eur J Immunol 27 (1997), p. 1242; D. J. Diamond, J. York, J. Sun, C. L. Wright and S. J. Forman, Blood 90 (1997), p. 1751). Recombinant protein vaccines do not reliably induce CTL responses (Habeshaw J A, Dalgleish A G, Bountiff L, Newell A L, Wilks, D, Walker L C, Manca F. November 1990; 11 (11): 418-25; Miller S B, Tse H, Rosenspire A J, King S R. Virology. December 1992; 191 (2):9 73-7). The use of otherwise immunogenic vaccines consisting of attenuated pathogens in humans is hampered, in several important diseases, by overriding safety concerns. In the last few years, epitope-based approaches have been proposed as a possible strategy to develop novel prophylactic and immunotherapeutic vaccines (Melief C J, Offringa R, Toes R E, Kast W M. Curr Opin Immunol. October 1996, 8(5):651-7; Chesnut R W, Design testing of peptide based cytotoxic T-cell mediated immunotherapeutic to treat infiction disease, cancer, in Ppowell, M F, Newman, M J (eds.): Vaccine Design: The Subunit, Adjuvant Approach, Plenum Press, New-York 1995, 847). This approach offers several advantages, including selection of naturally processed epitopes, which forces the immune system to focus on highly conserved and immunodominant epitopes of a pathogen (R. G. van der Most, A. Sette, C. Oseroff, J. Alexander, K. Murali-Krishna, L. L. Lau, S, Southwood, J. Sidney, R. W. Chesnut, M. Matioubian and R. Ahmed, J Immunol 157 (1996), p. 5543) and induction of multiepitopic responses to prevent escape by mutation such observed in HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. It also allows the elimination of suppressive T cell determinants, which might preferably elicit a TH2 response, in conditions where a TH1 responses is desirable, or vice-versa (Pfeiffer C, Murray J, Madri J, Bottomly K. Immunol Rev. October 1991; 123:65-84; P Chaturvedi, Q Yu, S Southwood, A Sette, and B Singh Int Immunol 1996 8: 745-755). It finally provides the possibility to get rid of autoimmune T cell determinants in antigens, which might induce undesirable autoimmune diseases. Protective antiviral or anti-tumoral immunity using CTL epitope-peptides has been achieved in several experimental models (D. J. Diamond, J. York, J. Sun, C. L. Wright and S. J. Forman, Blood 90 1997, p.1751; J. E. J. Blaney, E. Nobusawa, M. A. Brehm, R. H. Bonneau, L. M. Mylin, T. M. Fu, Y. Kawaoka and S. S. Tevethia, J Virol 72 (1998), p. 9567). CTL epitope definition based on the usage of human lymphocytes might be misleading due to environmental and genetic heterogeneity that lead to incomplete results, and due to technical difficulties in isolating CTL clones. HLA class I or class II transgenic mice described to date have proved to be a valuable tool to overcome these limitations as illustrated by the identification with such animal models of novel CTL and T helper epitopes (Hill A V. Annu Rev Immunol. 1998;16:593-617; Carmon L, El-Shami K M, Paz A., Pascolo S, Tzehoval E, Tirosb B, Koren R, Feldman M, Fridkin M, Lemonnier F A, Eisenbach L. Int J Cancer, Feb. 1, 2000; 85(3):391-7). These mice have also been used to demonstrate: i) good correlation between peptide HLA binding affinity and immunogenicity (Lustgarten J, Theobald M, Labadie C, LaFace D, Peterson P, Disis M L, Cheaver M A, Sherman L A. Hum Immunol. Febuary 1997; 52(2):109-18; Bakker A B, van der Burg S H, Huijbens R J, DRijfhout J W, Melief C J, Adema G J, Figdor C G. Int J Cancer. January 27, 1997; 70(3):302-9), ii) significant overlap between the murine and human CTL system at the level of antigen processing (same epitopes generated), and iii) comparable mobilization against most antigens of the CTL repertoires in HLA transgenic mice and humans (Wentworth, P. A., A. Vifiello, J. Sidney, E. Keogh, P, W. Chesnut, H. Grey, A. Sette. 1996. Eur. J. Immunol. 26:97; Alexander, J., C. Oserof, J. Sidney, P. Wentworth, E. Keogh, G. Hermanson, F. V. Chisari R. T, Kubo, H. M, Grey, A, Sette, 1997. J. Immunol. 159:4753). To date, synthetic peptide-based CTL epitope vaccines have been developed as immunotherapeutics against a number of human diseases [18-20]. However, only moderate efficacy was observed in several clinical trials (21). This may be partly explained by the failure of these vaccines to induce sufficiently strong CTL responses. Indeed, recent reports suggest the need for CD4+ T-cell help to obtain maximum CTL response (A. J. Zajac, K. Murali-Krishna, J. N. Blattman and R. Ahmed, Curr Opin Immunol 10 (1998), p. 444; Firat H, Garcia-Pons F, Tourdot S, Pascolo S, Scardino A, Garcia. Z, Michel M L, Jack R W, Jung O, Kosmatopoulos K, Mateo L, Suhrbier A, Lemonnier F A, Langlade-Dernoyen P Eur J Immunol 29, 3112,1999). CTL are critical components of protective immunity against viral infections, but the requirements for in vivo priming of CTL are not completely understood. It is now accepted that Th cells are usually essential for CTL priming with synthetic peptides. With respect to synthetic CTL epitopic peptides, several studies point to a mandatory need for Th lymphocyte stimulation to induce optimal CTL responses (C. Fayolle, E. Deriaud and C. Leclerc, J Immunol 147 (1991), p, 4069; C. Widmann, P. Romero, J. L. Maryanski, G. Corradin and D. Valmori, J Immunol Meth 155 (1992), p. 95; M. Shirai, C. D. Pendkton, J. Ahlers, T. Takeshita, M. Newman and J. A. Berzofsky, J Immunol 152 (1994), p. 549; J. P. Sauet, H. Gras-Masse, J. G. Guillet and E. Gomard, Int Immunol 8 (1996). p. 457). Several of these studies showed that activation of a CD8+ T cell requires simultaneous interaction of a CD4+ T helper cell and a CD8+ T cell with the same antigen-presenting cell presenting their cognate epitopes (Ridge J P, Di Rosa F, Matzinger P. Nature. Jun. 4, 1998; 3 93 (6684):474-8). The relevance of this three-cell interaction for priming of CTLs is confirmed by studies with viral epitopes, and animal models, since in vivo induction of CTLs was most efficient when CTL and Th epitopes were physically linked rather than administered as an unlinked mixture (Shirai M, Pendleton C D, Ahlers J, Takeshita T, Newman M, Berzohky J A. J Immunol. Jan. 15, 1994; 152(2): 549-56; Oseroff C, Sette A, Wentworth P, Celis E, Maewal A, Dahlberg C, Fikes J, Kubo R T, Chesnut R W, Grey B X Alexander J. Vaccine. May 1998; 16(8): 823-33). The capacity of CTL and Th antigenic peptides to efficiently induce CTL responses has been demonstrated both in experimental models (C. Fayolle, E. Deriaud and C. Leclerc, J Immunol 147 (1991), p, 4069; C. Widmann, P. Romero, J. L. Maryanski, G. Corradin and D. Valmori, J Immunol Meth 155 (1992), p. 95) and in humans (A. Vitiello, G. Ishioka, H. M. Grey, R. Rose, P. Famess, R. LaFond, L. Yuan, F. V. Chisari, J. Furze and R. Bartholomeuz, J Clin Invest 95 (1995), p. 341; B. Livingston, C. Crimi, H. Grey, G. Ishioka, F. V. Chisari, J. Fikes, H. M. Grey, R. Chesnut and A. Sette, J Immunol 159 (1997), p.1383). Moreover, a potent Th response plays an important role not only for optimal induction of CTL responses, but also for maintenance of CTL memory (E. A. Walter, P. D. Greenberg, M. J. Gilbert, R. J. Finch, K-S. Watanabe, E. D. Tbomas and S. R. Riddell, N Engl J Med 333 (1995), p.1038; Riddell S R, Greenberg P D, In Thomas E D, Blume K G, Forman S J (eds): Hematopoietic Cell Transplantation, 2nd edn. Maiden, MA: Blackwell Science Inc., 1999). Finally, it has long been documented that CD4+ T “helper” cells are crucial in coordinating cellular and humoral immune responses against exogenous antigens. Recently, a transgenic (Tg) mouse that expresses both HLA-A*0201 class I and HLA-DR1 class II molecules was established (BenMohamed L, Krishnan R, Longmate J, Auge C, Low L, Primus J, Diamond D J, Hum, Immunol. August 2000;61 (8):764-79). The authors reported that both HLA-A*0201 and HLA-DR1 transgenes are functional in vivo, that both MHC class I and class II molecules were utilized as restriction elements, and that the product of the HLA-DR1 transgene enhances the HLA-A*0201-restricted antigen-specific CTL responses (BenMohamed L, Krishnan R, Longmate J, Auge C, Low L, Primus J, Diamond D J, Hum, Immunol. August 2000;61 (8):764-79). It is noteworthy that these HLA-A*0201/DR1 Tg mice expressed their own MHC H-2 class I and class II molecules. Because HLA class I transgenic mice expressing endogenous mouse MHC class I genes preferentially and often exclusively develop H-2 restricted CTL response (C Barra, H Gournier, Z Garcia, P N Marche, E Jouvin-Marche, P Briand, P Fillipi, and F A Lemonnier J Immunol 1993 150: 3681-3689; Epstein H, Hardy F., May J S, Johnson M H, Holmes N. Eur J Immunol. September 1989;19(9):1575-83; Le A X; E J Bernhard, M J Holterman, S Strub, P Parham, E Lacy, and V H Engelhard J Immunol 1989 142: 13 66-1371; Vitiello A, Marchesini D, Furze J, Sherman L A, Chesnut R W., J Exp Med. Apr. 1, 1991;173(4):100715), and HLA class II transgenic mice expressing endogenous mouse MHC class II genes fail to induce reliable HLA class II restricted antigen-specific responses (Nishimura Y, Iwanaga T, Inamitsu T, Yanagawa Y, Yasunami M, Kimura A, Hirokawa K, Sasazuki T., J Immunol Jul. 1, 1990;145(1):353-60), these HLA-A*0201/DR1 Tg mice are of limited utility to assess human-specific responses to antigen. However, in HLA class I transgenic H-2 class I knock-out mice, or HLA class II transgenic H-2 class II knock-out mice, only HLA-restricted CTL immune responses occur (Pascolo S, Bervas N, Ure J M, Smith A G, Lemonnier F A, Perarnau, B., J Exp Med. Jun. 16, 1997;185(12).2043-51; Madsen L, Labrecque N, Engberg J, Dierich A, Svejgaard A, Benoist C, Mathis D, Fugger L. Proc Natl Acad Sci USA—Aug. 31, 1999;96(18):10338-43). In fact, HLA-A2.1-transgenic H-2 class I-knock-out (KO) mice exhibit the ability to mount enhanced HLA-A2.1-restricted responses as compared to HLA-A2.1-transgenic mice that still express the endogenous murine H-2 class I molecules (Pascolo, S. et al. J Exp Med 185, 2043-2051 (1997); Ureta-Vidal, A., Firat, H., Perarnau, B. & Lemonnier, F. A. J Immunol 163, 2555-2560 (1999); Firat, H. et al., Int Immunol 14, 925-934 (2002); Rohrlich, P. S. et al., Int Immunol 15, 765-772 (2003)). The inventors have made similar observations with HLA-DR1-transgenic mice, depending on whether or not they are deficient in H-2 class II molecules (A. Pajot, unpublished results). Furthermore, in the absence of competition from murine MHC molecules, the HLA-A2.1-transgenic H-2 class I-KO or HLA-DRI-transgenic H-2 class II-KO mice generate only HLA-restricted immune responses (Pascolo, S. et al. J Exp Med 185, 2043-2051 (1997)) (A. Pajot, unpublished results), facilitating the monitoring of HLA-restricted CD8 + and CD4 + T cell responses. However, protective immune responses against pathogens, which often require collaboration between T helper and cytotoxic CD8 + T cells, cannot be studied in the single HLA class I- or HLA class II-transgenic mice, which do not allow the simultaneous assessment of HLA class I and II human responses in the same mouse. Accordingly, there exists a need in the art for a convenient animal model system to test the immunogenicity of human vaccine candidates comprising constructs containing human CTL epitopes and, in some cases, with the inclusion of high potency CD4+ Th (helper T lymphocyte) epitopes to sustain antiviral and antitumoral CD8+ T-cell activity (A. J. Zajac, K. Murali-Krishna, J. N. Blattman and R. Ahmed, Curr Opin Immunol 10 (1998), p. 444; Firat H, Garcia-Pons F, Tourdot S, Pascolo S, Scardino A, Garcia Z, Michel M L, Jack R W, Jung O, Kosmatopoulos K, Mateo L, Suhrbier A, Lemonnier F A, Langlade-Dernoyen P, Eur J Immunol 29,3112, 1999). There is also a need for a system that allows the simultaneous assessment of the mutual coordination between a CTL response, a TH response (in particular s TH 1 or TH 2 response), and, optionally, a humoral response.
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<SOH> SUMMARY OF THE INVENTION <EOH>The inventors have met this need and more by providing mice transgenic for both HLA-A2.1 and HLA-DR1 molecules, in a background that is deficient for both H-2 class I and class II molecules. Specifically, the invention provides mice comprising (1) mutated H-2 class I and class II molecules; and (2) expressing HLA class I transgenic molecules, or HLA class II transgenic molecules, or HLA class I transgenic molecules and HLA class II transgenic molecules. These mice provide a model useful in the development and optimization of vaccine constructs with maximum in vivo immunogenicity for human use. Specifically, such mice enable a complete analysis of the three components of the immune adaptive response (antibody, helper and cytolytic) in a single animal, as well as an evaluation of the protection specifically conferred by vaccination against an antigenic challenge. Mice of the invention, which comprise a knock-out for both H-2 class I and class II molecules, and express HLA class I transgenic molecules and HLA class II transgenic molecules represent a completely humanized experimental mouse that can be used to simultaneously detect the presence of antigen-specific antibodies, an antigen-specific HLA-DRI restricted T cell response, and an antigen-specific HLA-A2 restricted T cell response. These mice will be useful to study how mutual coordination operates between a CTL response, a TH response (in particular a TH 1 or TH 2 response), and, optionally, a humoral response. These mice represent an optimized tool for basic and applied vaccinology studies. A first embodiment of the invention provides a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, and a functional HLA class I or class II transgene. A second embodiment of the invention provides a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. In some embodiments, the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. A further embodiment of the invention provides a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene. In an embodiment, the mouse has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°. In some embodiments the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. Another embodiment of the invention provides a method of simultaneously identifying the presence of one or more epitopes in a candidate antigen or group of antigens, where the one or more epitopes elicits a specific humoral response, a TH HLA-DR1 restricted response, and/or a CTRL HLA-A2 restricted response. The method comprises administering the candidate antigen or group of candidate antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAα°; assaying for a specific humoral response in the mouse to the antigen; assaying for a TH HLA-DR1 restricted response in the mouse to the antigen; and assaying for a CTRL HLA-A2 restricted response in the mouse to the antigen. Observation of a specific humoral response in the mouse to the antigen identifies an epitope that elicits a humoral response in the antigen. Observation of a TH HLA-DR1 restricted response in the mouse to the antigen identifies an epitope that elicits a TH HLA-DR1 restricted response in the antigen. Observation of a CTRL HLA-A2 restricted response in the mouse to the antigen identifies an epitope which elicits a CTRL HLA-A2 restricted response in the antigen. In some embodiments, the method includes assaying for a Th1-specific response in the mouse to the antigen and assaying for a Th2-specific response in the mouse to the antigen. In this case, observation of a Th1-specific response in the mouse to the antigen identifies an epitope that elicits a Th1-specific response in the mouse to the antigen, and observation of a Th2-specific response in the mouse to the antigen identifies an epitope that elicits a Th2-specific response in the mouse to the antigen. This invention also provides a method of identifying the presence of an HLA DR1-restricted T helper epitope in a candidate antigen or group of candidate antigens, the method comprising administering the candidate antigen or group of candidate antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°; and assaying for a TH HLA-DR1 restricted T helper epitope response in the mouse to the antigen. Observation of a TH HLA-DR1 restricted T helper epitope response in the mouse to the antigen identifies an epitope that elicits a TH HLA-DR1 restricted T helper epitope response in the antigen. In addition, this invention provides an isolated antigen comprising an HLA DR1-restricted T helper epitope identified by the method of the preceding paragraph. In some embodiments, the isolated antigen further includes an epitope that elicits a humoral response and/or an epitope that elicits a CTRL HLA-A2 restricted response. In some embodiments, the antigen comprising an HLA DR1-restricted T helper epitope comprises a polypeptide. In other embodiments, the antigen comprising an HLA DR1-restricted T helper epitope comprises a polynucleotide. In further embodiments, the antigen comprising an HLA DR1-restricted T helper epitope comprises DNA, RNA, or DNA and RNA. Further, this invention provides a method of identifying the presence of an HLA-A2-restricted T cytotoxic (CTL) epitope in a candidate antigen or group of candidate antigens, the method comprising administering the candidate antigen or group of candidate antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°; and assaying for an HLA-A2-restricted T cytotoxic (CTL) response in the mouse to the antigen or group of antigens. Observation of an HLA-A2-restricted T cytotoxic (CTL) response in the mouse to the antigen or group of antigens identifies an epitope that elicits a an HLA-A2-restricted T cytotoxic (CTL) response in the antigen or group of antigens. This invention provides an isolated antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope identified by the method of the preceding paragraph. In some embodiments, the antigen further comprises an epitope that elicits a humoral response and/or an epitope that elicits a TH HLA-DR1 restricted T helper epitope response. In some embodiments, the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises a polypeptide. In other embodiments, the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises a polynucleotide. In further embodiments, the antigen comprising an HLA-A2-restricted T cytotoxic (CTL) epitope comprises, DNA, RNA, or DNA and RNA. This invention also provides a method of comparing the efficiency of the T-helper cell response induced by two or more vaccines. This method comprises administering a first candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T-helper cell response induced in the mouse by the first candidate vaccine; administering a second candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T-helper cell response induced in the mouse by the second candidate vaccine; administering each additional candidate vaccine to be compared to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T-helper cell response induced in the mouse by the additional candidate vaccine, and determining the efficiency of each candidate vaccine to induce a T-helper cell response by comparing the T-helper cell responses to each of the vaccines to be compared with each other. In some embodiments the T-helper cell response is an HLA-DR1 restricted response. In addition, this invention provides a method of comparing the efficiency of T cytotoxic cell responses induced by two or more vaccines. The method includes administering a first candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T cytotoxic cell response induced in the mouse by the first candidate vaccine; administering a second candidate vaccine to a mouse of a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T cytotoxic cell response induced in the mouse by the second candidate vaccine; administering each additional candidate vaccine to be compared to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T cytotoxic cell response induced in the mouse by the additional candidate vaccine; and determining the efficiency of each candidate vaccine to induce a T cytotoxic cell response by comparing the T cytotoxic cell responses to each of the vaccines to be compared with each other. In some embodiments the T cytotoxic cell response is an HLA-A2 restricted response. Further, this invention provides a method of simultaneously comparing the efficiency of T-helper cell response and T cytotoxic cell response induced by two or more vaccines. The method comprises administering a first candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by the first candidate vaccine; administering a second candidate vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by the second candidate vaccine; administering each additional candidate vaccine to be compared to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and measuring the T-helper cell response and T cytotoxic cell response induced in the mouse by each additional candidate vaccine; and determining the efficiency of each candidate vaccine to induce a T-helper cell response and T cytotoxic cell response by comparing the T-helper cell response and T cytotoxic cell response to each of the vaccines to be compared with each other. In some embodiments the T-helper cell response is an HLA-DR1 restricted response, and the T cytotoxic cell response is an HLA-A2 restricted response. This invention also provides a method of simultaneously determining the humoral response, the T-helper cell response, and the T cytotoxic cell response of a mouse following its immunization with an antigen or a vaccine comprising one or more antigens. The method comprises administering the antigen or the vaccine comprising one or more antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and assaying for a specific humoral response in the mouse to the antigen or vaccine comprising one or more antigens, assaying for a T-helper cell response in the mouse to the antigen or vaccine comprising one or more antigens, and assaying for a T cytotoxic cell response in the mouse to the antigen or vaccine comprising one or more antigens. In some embodiments the T-helper cell response is a TH HLA-DR1 restricted response. In some embodiments the T cytotoxic cell response is a CTRL HLA-A2 restricted response. This invention also provides a method of optimizing two or more candidate vaccine compositions for administration to a human, based on preselected criteria. The method includes simultaneously determining the humoral response, the T-helper cell response, and the T cytotoxic cell response of a mouse following its immunization with the two or more candidate vaccine compositions, using a method comprising administering the antigen or the vaccine comprising one or more antigens to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, assaying for a specific humoral response in the mouse to the antigen or vaccine comprising one or more antigens, assaying for a T-helper cell response in the mouse to the antigen or vaccine comprising one or more antigens, assaying for a T cytotoxic cell response in the mouse to the antigen or vaccine comprising one or more antigens, and selecting an optimized vaccine by applying preselected criteria to the results. In some embodiments, the two or more vaccine candidates differ only in the ratio of antigen to adjuvant present in the vaccine. In some embodiments, the two or more vaccine candidates differ only in the type of adjuvant present in the vaccine. In another aspect, the invention provides a method of determining whether a vaccine poses a risk of induction of an autoimmune disease when administered to a human. The method comprises administering the vaccine to a transgenic mouse comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA-A2 transgene, and a functional HLA-DR1 transgene, or a transgenic mouse deficient for both H2 class I and class II molecules, wherein the transgenic mouse comprises a functional HLA class I transgene and a functional HLA class II transgene, and has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°, and assaying for an autoimmune response in the mouse, where observation of an autoimmune response in the mouse indicates that the vaccine poses a risk of induction of an autoimmune disease when administered to a human. This invention also provides an isolated transgenic mouse cell comprising a disrupted H2 class I gene, a disrupted H2 class II gene, and a functional HLA class I or class II transgene. In addition, the invention provides an isolated transgenic mouse cell comprising a disrupted H2 class I gene, a disrupted H2 class II gene, a functional HLA class I transgene, and a functional HLA class II transgene. In some embodiments, the HLA class I transgene is an HLA-A2 transgene and the HLA class II transgene is an HLA-DR1 transgene. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing. Further, this invention provides an isolated transgenic mouse cell deficient for both H2 class I and class II molecules, wherein the transgenic mouse cell comprises a functional HLA class I transgene and a functional HLA class II transgene. In some embodiments, the transgenic mouse cell has the genotype HLA-A2 + HLA-DR1 + β2m°IAβ°. In other embodiments, the HLA-A2 transgene comprises the HLA-A2 sequence provided in the sequence listing and the HLA-DR1 transgene comprises the HLA-DR1 sequence provided in the sequence listing.
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20040702
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20100216
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20050526
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70094.0
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HIRIYANNA, KELAGINAMANE T
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TRANSGENIC MICE HAVING A HUMAN MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) PHENOTYPE, EXPERIMENTAL USES AND APPLICATIONS
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UNDISCOUNTED
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ACCEPTED
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10,882,260
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ACCEPTED
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Semiconductor device with shallow trench isolation and its manufacture method
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A semiconductor device manufacturing method includes the steps of: (a) forming a stopper layer for chemical mechanical polishing on a surface of a semiconductor substrate; (b) forming an element isolation trench in the stopper layer and the semiconductor substrate; (c) depositing a nitride film covering an inner surface of the trench; (d) depositing a first oxide film through high density plasma CVD, the first oxide film burying at least a lower portion of the trench deposited with the nitride film; (e) washing out the first oxide film on a side wall of the trench by dilute hydrofluoric acid; (f) depositing a second oxide film by high density plasma CVD, the second oxide film burying the trench after the washing-out; and (g) removing the oxide films on the stopper layer by chemical mechanical polishing.
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1. A semiconductor device manufacturing method comprising the steps of: (a) forming a stopper layer for chemical mechanical polishing over a surface of a semiconductor substrate; (b) forming an element isolation trench in said stopper layer and said semiconductor substrate; (c) depositing a nitride film covering an inner surface of said trench; (d) depositing a first oxide film through high density plasma CVD, said first oxide film burying at least a lower portion of said trench deposited with said nitride film; (e) washing out said first oxide film over a side wall of said trench by hydrofluoric acid; (f) depositing a second oxide film by CVD, said second oxide film burying said trench after said washing-out; and (g) removing said oxide films over said stopper layer by chemical mechanical polishing. 2. The semiconductor device manufacturing method according to claim 1, wherein said step (f) deposits the second oxide film by high density plasma CVD. 3. The semiconductor device manufacturing method according to claim 1, wherein said trench after said step (c) has an aspect ratio of a depth to a width larger than 3. 4. The semiconductor device manufacturing method according to claim 1, wherein said trench after said step (c) has a frontage opening with a width of 60 nm or wider. 5. The semiconductor device manufacturing method according to claim 1, further comprising the step of (h) forming a thermally oxidized oxide film on exposed surface of said semiconductor substrate before each of said steps (a) and (c). 6. The semiconductor device manufacturing method according to claim 1, wherein said step (e) control-etches some of said exposed nitride film. 7. The semiconductor device manufacturing method according to claim 1, wherein said step (e) uses dilute hydrofluoric acid with water 10 to 200 times as much as hydrofluoric acid. 8. The semiconductor device manufacturing method according to claim 1, wherein said step (e) leaves said nitride film having a thickness of 7 nm or thinner in an upper area of said trench. 9. The semiconductor device manufacturing method according to claim 1, further comprising a step of (i) performing an annealing process after said step (f). 10. The semiconductor device manufacturing method according to claim 1, further comprising the steps of: (j) removing said stopper layer; and (k) forming a transistor in a region surrounded by said trench. 11. A semiconductor device comprising: a semiconductor substrate; an element isolation trench defining an active region in said semiconductor device; a nitride film covering an inner wall of said element isolation trench and having a step making an upper portion of said nitride film from an intermediate depth of said inner wall thinner than a lower portion; and a high density plasma oxide film burying a space defined by said nitride film in said element isolation trench. 12. The semiconductor device according to claim 11, wherein said high density plasma oxide film includes a first high density plasma oxide film burying an lower part of said space and a second high density plasma oxide film burying an upper part of said space on said first high density plasma oxide film. 13. The semiconductor device according to claim 11, further comprising an oxide liner film formed covering a surface of said element separation trench. 14. The semiconductor device according to claim 11, further comprising a transistor formed in said active region.
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CROSS REFERENCE TO RELATED APPLICATION This application is based on and claims priority of Japanese Patent Application No. 2004-060210 filed on Mar. 4, 2004, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION A) Field of the Invention The present invention relates to a semiconductor device and its manufacture method, and more particularly to a semiconductor device having shallow trench isolation (STI) and its manufacture method. B) Description of the Related Art Local oxidation of silicon (LOCOS) is known as one of element isolation methods for semiconductor devices. According to the technique of local oxidation of silicon, after a silicon oxide film is formed on a silicon substrate as a buffer layer, a silicon nitride film is formed as an oxidation preventing mask layer, and after the silicon nitride film is patterned, the surface of the silicon substrate is thermally oxidized via the silicon oxide film. While the silicon substrate is thermally oxidized, oxidation seeds such as oxygen and moisture intrude also into the buffer silicon oxide film under the silicon nitride film so that the silicon substrate surface under the silicon nitride film is also oxidized and silicon oxide regions called bird's beaks are formed. The regions where the bird's beaks are formed cannot be used substantially as an element forming region (active region) so that an area of the element forming region becomes small. If a substrate surface is thermally oxidized after a silicon nitride film having openings of various sizes is formed, the thickness of a silicon oxide film formed on the silicon substrate under an opening having a narrow size is thinner than that of a silicon oxide film formed on the silicon substrate under an opening having a broad size. This phenomenon is called thinning. As semiconductor devices are made finer, the area of the region not used as the element forming region increases in the whole region of a semiconductor substrate, because of bird's beaks and thinning. Namely, a ratio of narrowing the element forming region increases, hindering high integration of semiconductor devices. A trench isolation (TI) technique is known as the technique of forming an element isolation region. With this technique, a trench is formed under a semiconductor substrate surface, and insulator or polysilicon is buried in the trench. This method has been used conventionally with bipolar transistor LSI's which require deep element isolation regions. In order to eliminate both the bird's beak and thinning, trench isolation has been applied widely to MOS transistor LSI's. Since a MOS transistor LSI does not require element isolation as deep as that of a bipolar transistor, element isolation can be realized by a relatively shallow trench of about 0.1 to 1.0 μm deep. This structure is called shallow trench isolation (STI). STI forming processes will be described with reference to FIGS. 5A to 5H. As shown in FIG. 5A, on the surface of a silicon substrate 1, a silicon oxide film 2 having a thickness of, for example, 10 nm is formed by thermal oxidation. On this silicon oxide film 2, a silicon nitride film 3, e.g., 100 to 150 nm thick is formed by chemical vapor deposition (CVD). The silicon oxide film 2 functions as a buffer layer for relaxing a stress between the silicon substrate 1 and silicon nitride film 3. The silicon nitride film 3 functions as a stopper layer in a later polishing process. A resist pattern 4 is formed on the silicon nitride film 3. An opening defined by the resist pattern 4 defines the region where an element forming region is formed. The region of the silicon substrate under the resist pattern 4 becomes an active region where an element is formed. By using the resist pattern 4 as an etching mask, the silicon nitride film 3 exposed in the opening, the silicon oxide film 2 under the silicon nitride film and the silicon substrate 1 under the silicon oxide film are etched by reactive ion etching (RIE) to a depth of about 0.5 μm to form a trench 6. As shown in FIG. 5B, the silicon substrate surface exposed in the trench 6 is thermally oxidized to form a thermally oxidized silicon film, e.g., 10 nm thick. As shown in FIG. 5C, a silicon oxide film 9 burying the trench is formed on the silicon substrate, for example, by high density plasma (HDP) CVD. In order to make dense the silicon oxide film 9 to be used as the element isolation region, the silicon substrate is annealed, for example, in a nitrogen atmosphere at 900 to 1100° C. As shown in FIG. 5D, by using the silicon nitride film 3 as a stopper, an unnecessary silicon oxide film 9 is removed starting from the top surface thereof by chemical mechanical polishing (CMP) or reactive ion etching (RIE). The silicon oxide film 9 is left only in the trench defined by the silicon nitride film 3. Annealing may be performed at this stage in order to make dense the silicon oxide film. As shown in FIG. 5E, the silicon nitride film 3 is removed by hot phosphoric acid. Next, the buffer silicon oxide film 2 on the surface of the silicon substrate 1 is removed by dilute hydrofluoric acid. At this time, the silicon oxide film 9 buried in the trench is also etched. As shown in FIG. 5F, the surface of the silicon substrate 1 is thermally oxidized to form a sacrificial silicon oxide film 22 on the substrate surface. Impurity ions of a desired conductivity type are implanted into the surface layer of the silicon substrate 1 via the sacrificial silicon oxide film 22 and activated to form a well 10 of the desired conductivity type. The sacrificial silicon oxide film 22 is thereafter removed by dilute hydrofluoric acid. While the sacrificial silicon oxide film 22 is removed, the silicon oxide film 9 is also etched. As shown in FIG. 5G, the exposed surface of the silicon substrate is thermally oxidized to form a silicon oxide film 11 having a desired thickness which is used as a gate insulating film. A polysilicon film 12 is deposited on the silicon substrate 1 and patterned to form a gate electrode. As shown in FIG. 5H, impurity ions having the conductivity type opposite to that of the well 10 are implanted and activated to form source/drain regions S/D1. If necessary, side wall spacers SW are formed on the side walls of the gate electrode, and impurity ions having the conductivity type opposite to that of the well 10 are implanted again and activated to form high concentration source/drain regions S/D2. As silicon oxide is buried in the trench and an annealing process is performed in order to make dense the silicon oxide film 9, the silicon oxide film 9 becomes dense and is also compressed so that the element forming region surrounded by this silicon oxide film 9 receives a compression stress. As the compression stress is applied, the mobility of electrons in the active region of the silicon substrate 1 lowers greatly. A saturation drain current therefore lowers. As the active region becomes narrow because of finer elements, the influence of the compression stress becomes large. As shown in FIG. 5G, if the shoulders of the element isolation region 9 are etched and divots are formed under the gate electrode, the gate electrode surrounds not only the upper surface of the element forming region, but also the side walls of the shoulders of the element forming region of the silicon substrate. When a voltage is applied to the gate electrode having this shape, an electric field concentrates upon the shoulders of the element forming region so that a transistor having a lower threshold voltage is formed. This parasitic transistor forms the hump characteristics on the IV characteristics. As shown in FIG. 5H, an interlayer insulating film IL1 including an etch stopper layer is formed covering the gate electrode, and contact holes are formed reaching the source/drain regions S/D2. Conductive plugs PL are buried in the contact holes. In this case, if divots are being formed in STI under the contact holes, the contact holes are formed deeper than the active region surfaces. Therefore, the distance between the conductive plugs PL and the well 10 under the source/drain regions S/D2 becomes short, resulting in a possibility of leak current by tunneling or the like. Japanese Patent Laid-open Publication No. HEI-11-297812 proposes the following method. In order to suppress the formation of divots while the stopper nitride film is etched and removed and in order to prevent the hump characteristics and leak current, a silicon nitride film is formed on a silicon oxide film formed on the inner surface of a trench, a mask material is once filled in the trench, and the mask material is etched so that the surface level of the mask material in the trench becomes lower than the surface level of the semiconductor substrate, and the exposed silicon nitride film on the upper inner surface of the trench is removed. As the opening of a shallow trench becomes narrow, it becomes difficult to completely bury the inside of the trench with an insulating film. A seam may be formed at the interface of the insulating film or a void may be formed in the insulating film. If a seam or void exists, the void may be exposed during etching so that a morphology abnormality may occur or the manufacture yield at later processes may be lowered. Japanese Patent Laid-open Publication No. HEI-11-297811 proposes the following method. A nitride film is deposited on the surface of a semiconductor substrate, and a trench is formed through etching using a resist mask. The exposed surface is oxidized and a nitride film is deposited thereon, and thereafter a first TEOS film is deposited in the trench. After the first TEOS film is etched back through wet etching, a second TEOS film is deposited in the trench. Although element isolation by STI is suitable for miniaturization, there are problems inherent to STI. Various problems arise if a region is formed which has the STI surface lower than the active region surface. New technologies have been desired which can suppress the problems inherent to STI. SUMMARY OF THE INVENTION An object of this invention is to provide a manufacture method for semiconductor devices using STI capable of realizing good transistor characteristics. Another object of the present invention is to provide a semiconductor device having good transistor characteristics. According to one aspect of the present invention, there is provided a semiconductor device manufacturing method includes the steps of: (a) forming a stopper layer for chemical mechanical polishing over a surface of a semiconductor substrate; (b) forming an element isolation trench in the stopper layer and the semiconductor substrate; (c) depositing a nitride film covering an inner surface of the trench; (d) depositing a first oxide film through high density plasma oxidation, the first oxide film burying at least a lower portion of the trench deposited with the nitride film; (e) washing out the first oxide film over a side wall of the trench by hydrofluoric acid; (f) depositing a second oxide film by high density plasma oxidation, the second oxide film burying the trench after the washing-out; and (g) removing the oxide films over the stopper layer by chemical mechanical polishing. According to another object of the present invention, there is provided a semiconductor device comprising: a semiconductor substrate; an element isolation trench defining an active region in the semiconductor device; a nitride film covering an inner wall of the element isolation trench and having a step making an upper portion of the nitride film thin from an intermediate depth of the inner wall; and a high density plasma oxide film burying a space defined by the nitride film in the element isolation trench. A compression stress of the high density plasma oxide film is relaxed by a tensile stress of the silicon nitride film, so that drain current can be increased. A high density plasma oxidation process is executed twice or more and the oxide film on the side wall is removed by a wash-out process inserted between the high density plasma oxidation processes, so that the trench can be buried with the insulating film. Since the nitride film is left on the side wall, divots are prevented from being formed on the side areas of an active region, and the generation of hump and the increase in leak current of a transistor formed in the active region can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A to 1G are cross sectional views illustrating an STI forming method according to an embodiment of the present invention. FIG. 2 is a graph showing the relation of the etching rate between an oxide film and a nitride film etched by dilute hydrofluoric acid. FIG. 3 is a cross sectional view showing the structure of a semiconductor element formed in an active region. FIG. 4 is a cross sectional view schematically showing the structure of a semiconductor integrated circuit device. FIGS. 5A to 5H are cross sectional views illustrating an STI forming method according to a conventional technique. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A to 1G are cross sectional views of a semiconductor substrate illustrating the main processes of a method of manufacturing a semiconductor device according to an embodiment of the invention. As shown in FIG. 1A, the surface of a silicon substrate 1 is wet oxidized at 800° C. to form a buffer oxide film 2 of about 5 nm thick. Next, a silicon nitride layer 3 is formed having a thickness of, for example, 112 nm by chemical vapor deposition (CVD) at a substrate temperature of 775° C. This silicon nitride layer 3 provides a function of a stopper layer during chemical mechanical polishing (CMP). CVD for the silicon nitride layer may use, for example, dichlorosilane and ammonia or the like as the source materials. A photoresist mask 4 is formed on the silicon nitride layer 3. This photoresist mask 4 defines a pattern on the active region where an element is formed and has an opening in the region where an element isolation is formed. By using the photoresist pattern 4 as an etching mask, the silicon nitride layer 3, silicon oxide layer 2 and substrate 1 are etched to form a trench 6 for element isolation (shallow trench isolation, STI). The space between semiconductor elements is very narrow because of high integration of recent semiconductor devices. The width of an STI trench is therefore narrow. For example, a trench having a depth of 370 nm is formed at the width of 140 nm. The photoresist pattern 4 may be extinguished during this etching process. After the photoresist pattern 4 extinguishes, the pattern of the silicon nitride layer 3 functions a hard mask. If the photoresist pattern 4 is left, it is removed after etching. As shown in FIG. 1B, a thermally oxidized liner oxide film 7 of 5 nm to 10 nm thick is formed on the surface of the silicon substrate exposed in the trench, by dry oxidation, wet oxidation or hydrochloric acid oxidation. After the thermally oxidized liner oxide film 7 is formed, a silicon nitride liner film 8 is deposited by CVD on the substrate surface including the trench surface. The source gases may be dichlorosilane and ammonia, bistertialbutylaminosilane (BTBAS) and ammonia, or the like. The thicker the silicon nitride film, the better, in order to exhibit a high tensile stress cancelling out a compression stress of the silicon oxide film generated by high density plasma oxidization. In order to allow an oxide film to be buried at a later process, the thickness of the silicon nitride liner film 8 is set so that the width of 60 nm or wider is left at the frontage of the trench after the nitride film was formed. In the case of the trench having a width of 140 nm, the silicon nitride film 8 having a thickness of 40 nm or thinner (e.g., 30 nm to 40 nm) is deposited to ensure the frontage having a width of 60 nm or wider. There is the data that it is preferable to set the thickness of the silicon nitride liner layer to 8 nm or thinner or 20 nm or thicker in order to suppress peeling or separation of STI. For example, by using dichlorosilane and ammonia as source gases, a silicon nitride film having a thickness of 20 nm or thicker can be formed at a substrate temperature of 650° C. By using BTBAS and ammonia as source gases, a silicon nitride film having a thickness of 6 nm can be formed at a substrate temperature of 580° C. As shown in FIG. 1C, an oxide film is deposited by high density plasma (HDP) CVD in the trench formed with the silicon nitride liner film 8 to form a first oxide film 9a. For example, the first high density plasma oxide film 9a is deposited to a thickness of 140 nm at the flat surface, by supplying a high frequency RF power of 3200 W to the upper electrode and a low frequency RF power of 2100 W to the lower electrode, while silane of 120 cc, oxygen of 160 cc and He of 500 cc are flowed as source gases. Although the oxide film 9a is deposited from the bottom of the trench, it is difficult to prevent the side wall of the oxide film in the upper trench area from gradually extending. Even if a trench having an aspect ratio of, for example, over 3 is to be buried by one high density plasma oxidation, a void is likely to be formed in the upper trench area. As shown in FIG. 1D, after the trench is buried to the intermediate depth thereof, preferably to the half depth or more, wash-out is performed by dilute hydrofluoric acid. Dilute hydrofluoric acid contains water 10 to 100 times as much as hydrofluoric acid. This wash-out removes the oxide film formed on the side wall extending in the trench upper area. As the oxide film 9a is etched, the underlying nitride film 8 is exposed. Since the silicon nitride film deposited by CVD contains H, it is etched by hydrofluoric acid. For example, as the dilute hydrofluoric acid solution for wash-out, YGH is used which is a mixture of 0.2% HF (Y), H2O2+NH3+H2O)=1:2:110 (G) and H2O2+HCL+H2O=1:2:110 (H), and etching is performed at an etching amount corresponding to a thickness of 14 nm of the thermally oxidized film. FIG. 2 is a graph showing a comparison of an etching amount between an oxide film and a nitride film etched by dilute hydrofluoric acid. Measured plots are almost on a straight line. For example, if an oxide film of 10 nm thick is etched, a nitride film is etched by about 2.7 nm assuming that the nitride film exists. By control etching which controls the etching time of dilute hydrofluoric acid, the silicon nitride film 8 is left by a thickness of, for example, about 5 nm. By leaving some of the silicon nitride film 8, it is possible to suppress divots from being formed at a later process. If the thickness of the upper level nitride film 8 is set to 7 nm or thinner, during the etching by hot phosphoric acid after chemical mechanical polishing (CMP), it is possible to prevent the nitride film 8 in the trench from being etched. Hot phosphoric acid is hard to enter a gap of 7 nm or thinner because it is relatively viscous liquid. If the thickness of the nitride liner film is set to 7 nm or thinner in its upper area, during the etching process for the silicon nitride film by hot phosphoric acid after STI is formed, even if the upper end portion of the nitride liner film is etched the etching will not progress further because hot phosphoric acid is hard to permeate into the nitride liner film. As shown in FIG. 1E, a second oxide film 9b is deposited by high density plasma on the substrate with the oxide film on the upper side wall of the trench being removed. Since the oxide film on the side wall is removed, the trench can be buried properly without forming a void, seam or the like. The second high density plasma oxidation is performed by a thickness of about 265 nm by using the same source gases and RF powers as those of the first high density plasma oxidation. A relatively thick oxide film is deposited in order to bury the trench reliably. As shown in FIG. 1F, the high density plasma oxide films 9b and 9a (and nitride liner film 8) deposited on the nitride film 3 are removed by chemical mechanical polishing. A portion of the stopper nitride film 3 may be polished. After CMP, annealing is performed at a temperature of, for example, 1000° C. to make dense the oxide film and ensure the tensile stress of the nitride film. As shown in FIG. 1G, the silicon nitride film 3 functioned as the stopper layer is removed by hot phosphoric acid. If the upper thickness of the silicon nitride film 8 on the STI side wall formed as the liner layer is 7 nm or thinner, hot phosphoric acid is hard to permeate into this narrow width and etching will not progress in the nitride liner film. Thereafter, the buffer silicon oxide film 2 is etched and removed, a thermally oxidized sacrificial film is formed, and thereafter ions are implanted to form a well. The thermally oxidized sacrificial film is etched and removed, and a thermally oxidized film is formed as a gate insulating film. While the oxide film is etched, the liner oxide film 7 is also etched in some cases. As the thickness of the oxide film is set to about 5 nm or thinner, wet etchant such as dilute hydrofluoric acid is hard to permeate so that etching the liner oxide film 7 can be suppressed. Since the liner nitride film 8 is left on the STI surface, divots can be suppressed from being formed during the etching process. FIG. 3 is a cross sectional view of a MOS transistor formed in the active region surrounded and defined by the element isolation region. A p-type well 10 is formed in an active region of a p-type silicon substrate 1. An n-type well is also formed in another active region. After a through oxide film is removed, a gate insulating film 11 is formed on the surface of the active region by thermal oxidation, and a gate electrode layer 12 of polysilicon is formed on the gate insulating film 11. After the gate electrode layer 12 is patterned, n-type impurity ions are implanted in order to form source/drain regions S/D1 as extensions. Pocket regions Pt may be formed surrounding the extensions by implanting p-type impurity ions. A silicon oxide layer or the like is deposited on the substrate surface, and anisotropically etched by reactive ion etching (RIE) to leave side wall spacers SW only on the side walls of the gate electrode 12. At this stage, n-type impurity ions are again implanted to form high concentration source/drain regions S/D2. On the substrate surface, for example a Co film is deposited to from a cobalt silicide film 13 on the silicon surface by a salicide reaction. An unreacted Co film is washed out to form a low resistance cobalt silicide film 13 by a secondary reaction. A silicon nitride film 14 functioning as an etch stopper is formed on the substrate surface. On this film, an oxide film 15 functioning as an interlayer insulating film is deposited by CVD. The oxide film 15 may be a PSG film, a BPSG film, a plasma TEOS oxide film, a high density plasma oxide film or the like. After the surface of the interlayer insulating film 15 is planarized, contact holes are formed and a glue layer 16 such as a Ti/TiN laminated layer is deposited in the contact holes by sputtering or CVD. If the contact holes extend to the STI region as shown in FIG. 3 and divots exist near the border of the STI region, the contact metal extends downward surrounding the shoulders of the active region. After the glue layer 16 is deposited, for example W is deposited by CVD to form conductive plugs 17. Unnecessary metals on the interlayer insulating film are removed by CMP or the like. In the above description, although an n-channel MOS transistor is formed by way of example, a p-channel MOS transistor can be formed by similar processes. In this case, the conductivity type of impurities is inverted from n-type to p-type and vice versa. In the description of the above embodiment, the depth of STI is set to 370 nm and the width is set to 140 nm, this STI being used for a high speed and low voltage device. If a device requires a higher voltage and does not require a particular high speed, the trench width is set to about 200 nm and the depth is set to 370 nm same as the high speed and low voltage device. If the trench width is 200 nm and the trench frontage is narrower than 120 nm after the liner nitride film is formed, it is difficult to bury the trench by one high density plasma oxidation process. As in the above embodiment, since two high density plasma oxidation processes are executed, the trench can be buried appropriately. FIG. 4 is a schematic cross sectional view showing the structure of a semiconductor integrated circuit device. A semiconductor substrate 1 is formed with p-wells and n-wells, an n-channel MOS transistor is formed in the p-well, and a p-channel MOS transistor is formed in the n-well. In the structure shown in FIG. 4, pocket regions Pt of an opposite conductivity type are formed surrounding source/drain regions S/D1 as extensions. A cobalt silicide layer 13 is formed on the silicon surface, and a silicon nitride layer 14 covers the cobalt silicide layer 13. Conductive plugs PL are buried through an interlayer insulating film 15. An interlayer insulating film 19 is formed on the interlayer insulating film 15, and an etching stopper layer 20 is formed on the interlayer insulating film 19. Trenches are formed through the etching stopper layer 20 and interlayer insulating film 19, and first wiring layers W1 of copper or the like are buried in the trenches. An etching stopper layer ES2 having an oxygen intercepting function covers the surface of the first wiring layers W1, a second interlayer insulating film IL2 is stacked, and second wiring layers W2 of a dual damascene structure are formed. An etching stopper layer ES3 having an oxygen intercepting function covers the surface of the second wiring layers W2, a third interlayer insulating film IL3 is stacked, and third wiring layers W3 of the dual damascene structure are formed through the third interlayer insulating film IL3 and third etching stopper layer ES3. An etching stopper layer ES4 having an oxygen intercepting function covers the surface of the third wiring layers W3, a fourth interlayer insulating film IL4 is stacked, and fourth wiring layers W4 of the dual damascene structure are formed. An etching stopper layer ES5 having an oxygen intercepting function covers the surface of the fourth wiring layers W4, a fifth interlayer insulating film IL5 is stacked, and fifth wiring layers W5 of the dual damascene structure are formed through the fifth interlayer insulating film IL5 and fifth etching stopper layer ES5. An etching stopper layer ES6 having an oxygen intercepting function covers the surface of the fifth wiring layers W5, and a sixth interlayer insulating film IL6 is stacked on the fifth wiring layers W5. Copper wiring plugs PDB as the base of a pad are buried through the sixth interlayer insulating film IL6 and sixth etching stopper layer ES6. A pad PD made of, for example, aluminum is formed on the pad base PDB. In the region other than the pad, a seventh etching stopper layer ES7 is formed on the sixth interlayer insulating film IL6 and a passivation layer PT is formed on the seventh etching stopper layer ES7. As the material of the interlayer insulating film, a silicon oxide film having a dielectric constant lower than that of CVD silicon oxide, an organic insulating film and the like may be used in addition to silicon oxide. Both the organic insulating film and silicon oxide film may be used as lower level interlayer insulating films of a multi-layer wiring structure and higher level interlayer insulating films, respectively. The present invention has been described in connection with the preferred embodiments. The invention is not limited only to the above embodiments. It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.
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<SOH> BACKGROUND OF THE INVENTION <EOH>A) Field of the Invention The present invention relates to a semiconductor device and its manufacture method, and more particularly to a semiconductor device having shallow trench isolation (STI) and its manufacture method. B) Description of the Related Art Local oxidation of silicon (LOCOS) is known as one of element isolation methods for semiconductor devices. According to the technique of local oxidation of silicon, after a silicon oxide film is formed on a silicon substrate as a buffer layer, a silicon nitride film is formed as an oxidation preventing mask layer, and after the silicon nitride film is patterned, the surface of the silicon substrate is thermally oxidized via the silicon oxide film. While the silicon substrate is thermally oxidized, oxidation seeds such as oxygen and moisture intrude also into the buffer silicon oxide film under the silicon nitride film so that the silicon substrate surface under the silicon nitride film is also oxidized and silicon oxide regions called bird's beaks are formed. The regions where the bird's beaks are formed cannot be used substantially as an element forming region (active region) so that an area of the element forming region becomes small. If a substrate surface is thermally oxidized after a silicon nitride film having openings of various sizes is formed, the thickness of a silicon oxide film formed on the silicon substrate under an opening having a narrow size is thinner than that of a silicon oxide film formed on the silicon substrate under an opening having a broad size. This phenomenon is called thinning. As semiconductor devices are made finer, the area of the region not used as the element forming region increases in the whole region of a semiconductor substrate, because of bird's beaks and thinning. Namely, a ratio of narrowing the element forming region increases, hindering high integration of semiconductor devices. A trench isolation (TI) technique is known as the technique of forming an element isolation region. With this technique, a trench is formed under a semiconductor substrate surface, and insulator or polysilicon is buried in the trench. This method has been used conventionally with bipolar transistor LSI's which require deep element isolation regions. In order to eliminate both the bird's beak and thinning, trench isolation has been applied widely to MOS transistor LSI's. Since a MOS transistor LSI does not require element isolation as deep as that of a bipolar transistor, element isolation can be realized by a relatively shallow trench of about 0.1 to 1.0 μm deep. This structure is called shallow trench isolation (STI). STI forming processes will be described with reference to FIGS. 5A to 5 H. As shown in FIG. 5A , on the surface of a silicon substrate 1 , a silicon oxide film 2 having a thickness of, for example, 10 nm is formed by thermal oxidation. On this silicon oxide film 2 , a silicon nitride film 3 , e.g., 100 to 150 nm thick is formed by chemical vapor deposition (CVD). The silicon oxide film 2 functions as a buffer layer for relaxing a stress between the silicon substrate 1 and silicon nitride film 3 . The silicon nitride film 3 functions as a stopper layer in a later polishing process. A resist pattern 4 is formed on the silicon nitride film 3 . An opening defined by the resist pattern 4 defines the region where an element forming region is formed. The region of the silicon substrate under the resist pattern 4 becomes an active region where an element is formed. By using the resist pattern 4 as an etching mask, the silicon nitride film 3 exposed in the opening, the silicon oxide film 2 under the silicon nitride film and the silicon substrate 1 under the silicon oxide film are etched by reactive ion etching (RIE) to a depth of about 0.5 μm to form a trench 6 . As shown in FIG. 5B , the silicon substrate surface exposed in the trench 6 is thermally oxidized to form a thermally oxidized silicon film, e.g., 10 nm thick. As shown in FIG. 5C , a silicon oxide film 9 burying the trench is formed on the silicon substrate, for example, by high density plasma (HDP) CVD. In order to make dense the silicon oxide film 9 to be used as the element isolation region, the silicon substrate is annealed, for example, in a nitrogen atmosphere at 900 to 1100° C. As shown in FIG. 5D , by using the silicon nitride film 3 as a stopper, an unnecessary silicon oxide film 9 is removed starting from the top surface thereof by chemical mechanical polishing (CMP) or reactive ion etching (RIE). The silicon oxide film 9 is left only in the trench defined by the silicon nitride film 3 . Annealing may be performed at this stage in order to make dense the silicon oxide film. As shown in FIG. 5E , the silicon nitride film 3 is removed by hot phosphoric acid. Next, the buffer silicon oxide film 2 on the surface of the silicon substrate 1 is removed by dilute hydrofluoric acid. At this time, the silicon oxide film 9 buried in the trench is also etched. As shown in FIG. 5F , the surface of the silicon substrate 1 is thermally oxidized to form a sacrificial silicon oxide film 22 on the substrate surface. Impurity ions of a desired conductivity type are implanted into the surface layer of the silicon substrate 1 via the sacrificial silicon oxide film 22 and activated to form a well 10 of the desired conductivity type. The sacrificial silicon oxide film 22 is thereafter removed by dilute hydrofluoric acid. While the sacrificial silicon oxide film 22 is removed, the silicon oxide film 9 is also etched. As shown in FIG. 5G , the exposed surface of the silicon substrate is thermally oxidized to form a silicon oxide film 11 having a desired thickness which is used as a gate insulating film. A polysilicon film 12 is deposited on the silicon substrate 1 and patterned to form a gate electrode. As shown in FIG. 5H , impurity ions having the conductivity type opposite to that of the well 10 are implanted and activated to form source/drain regions S/D 1 . If necessary, side wall spacers SW are formed on the side walls of the gate electrode, and impurity ions having the conductivity type opposite to that of the well 10 are implanted again and activated to form high concentration source/drain regions S/D 2 . As silicon oxide is buried in the trench and an annealing process is performed in order to make dense the silicon oxide film 9 , the silicon oxide film 9 becomes dense and is also compressed so that the element forming region surrounded by this silicon oxide film 9 receives a compression stress. As the compression stress is applied, the mobility of electrons in the active region of the silicon substrate 1 lowers greatly. A saturation drain current therefore lowers. As the active region becomes narrow because of finer elements, the influence of the compression stress becomes large. As shown in FIG. 5G , if the shoulders of the element isolation region 9 are etched and divots are formed under the gate electrode, the gate electrode surrounds not only the upper surface of the element forming region, but also the side walls of the shoulders of the element forming region of the silicon substrate. When a voltage is applied to the gate electrode having this shape, an electric field concentrates upon the shoulders of the element forming region so that a transistor having a lower threshold voltage is formed. This parasitic transistor forms the hump characteristics on the IV characteristics. As shown in FIG. 5H , an interlayer insulating film IL 1 including an etch stopper layer is formed covering the gate electrode, and contact holes are formed reaching the source/drain regions S/D 2 . Conductive plugs PL are buried in the contact holes. In this case, if divots are being formed in STI under the contact holes, the contact holes are formed deeper than the active region surfaces. Therefore, the distance between the conductive plugs PL and the well 10 under the source/drain regions S/D 2 becomes short, resulting in a possibility of leak current by tunneling or the like. Japanese Patent Laid-open Publication No. HEI-11-297812 proposes the following method. In order to suppress the formation of divots while the stopper nitride film is etched and removed and in order to prevent the hump characteristics and leak current, a silicon nitride film is formed on a silicon oxide film formed on the inner surface of a trench, a mask material is once filled in the trench, and the mask material is etched so that the surface level of the mask material in the trench becomes lower than the surface level of the semiconductor substrate, and the exposed silicon nitride film on the upper inner surface of the trench is removed. As the opening of a shallow trench becomes narrow, it becomes difficult to completely bury the inside of the trench with an insulating film. A seam may be formed at the interface of the insulating film or a void may be formed in the insulating film. If a seam or void exists, the void may be exposed during etching so that a morphology abnormality may occur or the manufacture yield at later processes may be lowered. Japanese Patent Laid-open Publication No. HEI-11-297811 proposes the following method. A nitride film is deposited on the surface of a semiconductor substrate, and a trench is formed through etching using a resist mask. The exposed surface is oxidized and a nitride film is deposited thereon, and thereafter a first TEOS film is deposited in the trench. After the first TEOS film is etched back through wet etching, a second TEOS film is deposited in the trench. Although element isolation by STI is suitable for miniaturization, there are problems inherent to STI. Various problems arise if a region is formed which has the STI surface lower than the active region surface. New technologies have been desired which can suppress the problems inherent to STI.
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<SOH> SUMMARY OF THE INVENTION <EOH>An object of this invention is to provide a manufacture method for semiconductor devices using STI capable of realizing good transistor characteristics. Another object of the present invention is to provide a semiconductor device having good transistor characteristics. According to one aspect of the present invention, there is provided a semiconductor device manufacturing method includes the steps of: (a) forming a stopper layer for chemical mechanical polishing over a surface of a semiconductor substrate; (b) forming an element isolation trench in the stopper layer and the semiconductor substrate; (c) depositing a nitride film covering an inner surface of the trench; (d) depositing a first oxide film through high density plasma oxidation, the first oxide film burying at least a lower portion of the trench deposited with the nitride film; (e) washing out the first oxide film over a side wall of the trench by hydrofluoric acid; (f) depositing a second oxide film by high density plasma oxidation, the second oxide film burying the trench after the washing-out; and (g) removing the oxide films over the stopper layer by chemical mechanical polishing. According to another object of the present invention, there is provided a semiconductor device comprising: a semiconductor substrate; an element isolation trench defining an active region in the semiconductor device; a nitride film covering an inner wall of the element isolation trench and having a step making an upper portion of the nitride film thin from an intermediate depth of the inner wall; and a high density plasma oxide film burying a space defined by the nitride film in the element isolation trench. A compression stress of the high density plasma oxide film is relaxed by a tensile stress of the silicon nitride film, so that drain current can be increased. A high density plasma oxidation process is executed twice or more and the oxide film on the side wall is removed by a wash-out process inserted between the high density plasma oxidation processes, so that the trench can be buried with the insulating film. Since the nitride film is left on the side wall, divots are prevented from being formed on the side areas of an active region, and the generation of hump and the increase in leak current of a transistor formed in the active region can be suppressed.
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20040702
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20070501
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20050908
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76000.0
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VU, DAVID
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SEMICONDUCTOR DEVICE WITH SHALLOW TRENCH ISOLATION AND ITS MANUFACTURE METHOD
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,882,338
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ACCEPTED
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Magnetoresistance effect element and magnetic head
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A magnetoresistance effect element is composed of a substrate, and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate. The pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and the domain stability control including a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer.
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1. A magnetoresistance effect element comprising: a substrate; and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate, said pinned layer being composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and said domain stability layer including a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer. 2. A magnetoresistance effect element according to claim 1, wherein said free layer has same direction of magnetization as that of the ferromagnetic layer constituting the domain stability layer. 3. A magnetoresistance effect element according to claim 1, wherein said ferromagnetic layer forming the free layer has a direction of magnetization normal to that of the first and second ferromagnetic layers forming the pinned layer. 4. A magnetoresistance effect element according to claim 1, wherein said first and second ferromagnetic layers forming the pinned layer have directions of magnetization which are anti-parallel to each other. 5. A magnetoresistance effect element according to claim 1, wherein the two ferromagnetic layers disposed on both sides of the insulating layer are each formed of a ferromagnetic material having spin polarization of not less than 0.5. 6. A magnetoresistance effect element according to claim 1, wherein said dimension of the nano-contact portion includes at least one of a length in the layer lamination direction and a length of lateral width, extending in a direction normal to the lamination direction, said dimension being not more than Fermi length, preferably of not more than 100 nm. 7. A magnetoresistance effect element comprising: a substrate; a layer lamination structure disposed on the substrate and comprising a buffer layer, a free layer composed of a ferromagnetic layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a pinned layer and an anti-ferromagnetic layer, which are laminated in the described order on the substrate; side insulating layer disposed on both side portions of the layer lamination structure; and domain stability layers disposed on both side portions of the layer lamination structure through the side insulating layer, respectively, said pinned layer being composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the insulating layer, and said domain stability layer being composed of a ferromagnetic layer and an anti-ferromagnetic layer. 8. A magnetoresistance effect element according to claim 7, wherein said free layer has same direction of magnetization as that of the ferromagnetic layer constituting the domain stability control layer. 9. A magnetoresistance effect element according to claim 7, wherein said ferromagnetic layer forming the free layer has a direction of magnetization normal to that of the first and second ferromagnetic layers forming the pinned layer. 10. A magnetoresistance effect element according to claim 7, wherein said first and second ferromagnetic layers forming the pinned layer have directions of magnetization which are anti-parallel to each other. 11. A magnetoresistance effect element according to claim 7, wherein the two ferromagnetic layers disposed on both sides of the insulating layer are each formed of a ferromagnetic material having spin polarization of not less than 0.5. 12. A magnetoresistance effect element according to claim 7, wherein said dimension of the nano-contact portion includes at least one of a length in the layer lamination direction and a length of lateral width, extending in a direction normal to the lamination direction, said dimension being not more than Fermi length, preferably of not more than 100 nm. 13. A magnetic head comprising: a magnetoresistance effect element; electrodes disposed on both sides of the magnetoresistance effect element; and a pair of shield members disposed on outside surfaces of the electrodes, respectively, said magnetoresistance effect element comprising: a substrate; and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate, wherein said pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and said magnetic stability control layer is composed of a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer. 14. A magnetic head comprising: a magnetoresistance effect element; electrodes disposed on both sides of the magnetoresistance effect element; and a pair of shield members disposed on outside surfaces of the electrodes, respectively, said magnetoresistance effect element comprising: a substrate; a layer lamination structure disposed on the substrate and comprising a buffer layer, a free layer composed of a ferromagnetic layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a pinned layer and an anti-ferromagnetic layer, which are laminated in the described order on the substrate; side insulating layer disposed on both side portions of the layer lamination structure; and domain stability layers disposed on both side portions of the layer lamination structure through the side insulating layer, respectively, wherein said pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the insulating layer, and said magnetic stability control layer is composed of a ferromagnetic layer and an anti-ferromagnetic layer.
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BACKGROUND OF THE INVENTION 1. Field of The Invention The present invention relates to a magnetoresistance (or magneto-resistance) effect element particularly provided with Ballistic Magneto Resistance (BMR) effect and also relates to a magnetic head provided with such magnetoresistance effect element. 2. Relevant Art Generally, a giant magnetoresistance effect (GMR effect) is a phenomenon indicating rate of change in magnetoresistance (called herein MR ratio) which is developed or reviled in a case that electric current passes in a plane of a lamination structure of ferromagnetic layer/non-magnetic layer/ferromagnetic layer. Moreover, the magnetoresistance effect element of such GMR has been further actively studied for the development of more large MR ratio, and up to now, ferromagnetic tunnel junction and a CPP (Current Perpendicular to Plane)-type MR element, in which the current passes perpendicularly with respect to the lamination structure, have been developed, and hence, has high degree of expectation for reproducing (regenerative) element for magnetic sensor, magnetic recording element and the like. In the field of the magnetic recording technology, according to improvement of recording density, it has been a progress to make compact recording bits, and as its result, it becomes difficult to obtain a sufficient signal strength. Thus, taking such matters into consideration, it has been desired for engineers in this field to search a material having high sensitive magnetoresistance effect and develop or revile an element indicating a large MR ratio. Recently, there have been reported, as material indicating MR ratio of more than 100%, “magnetic micro contact” which is formed by butting two needle-like nickel (Ni) as shown, for example, in a document of “Physical Review Letters, vol. 82, p2923 (1999), by N. Garcia, M. Munoz, and Y. -W. Zhao” (Document 1). This magnetic micro contact is manufactured by butting two ferromagnetic materials arranged in form of needle or in form of triangle. More recently, there has been developed a magnetic micro contact in which two fine Ni wires are arranged in T-shape and micro column is grown at a contact portion of these wires by electro-deposition method (for example, refer to a document of “Appl. Phys. Lett. Vol. 80, p1785 (2002), by N. Garcia, G. G. Qian, and I. G. Sveliev” (Document 2). It is considered that an extremely high MR ratio developing such element is based on spin transport of a magnetic area existing in the magnetic nano contact formed between two ferromagnetic layers having magnetized directions in anti-parallel to each other. It is considered that, in the magnetoresistance effect element utilizing the magnetic nano contact having such characteristics, since electrons pass without receiving any scattering or diffusion (i.e., pass ballistically), such magnetoresistance effect element is called BMR element (Ballistic Magneto Resistance element). In addition, more recently, there has also been reported a magnetoresistance effect element having such magnetic nano contact. For example, in Japanese Patent Laid-open (KOKAI) Publication No. 2003-204095 (Document 3), there is reported a magnetoresistance effect element composed of first ferromagnetic layer/insulating layer/second ferromagnetic layer, in which the first ferromagnetic layer is connected to the second ferromagnetic layer at a predetermined portion of the insulating layer, the magnetoresistance effect element being provided with a hole having the maximum diameter of less than 20 nm. Furthermore, in Japanese Patent Application National Publication (Laid-open) No. HEI 11-510911 (Document 4), there is reported a magneto-resistance effect element composed of two magnetic layers connected to each other through a narrow segment having a width of about 100 nm. However, in consideration of application of a BMR element to a magnetic head, a dimension of a free layer sensitive to magnetic field leaking from a surface of a medium is made small such as, for example, to several tens nm. In a case of recording density of 1 Tbits/in2, a read head of 40 to 50 nm width is required, and in a case of a BMR element capable of realizing an extremely high MR ratio, a structure of a magnetic domain of the magnetic nano contact (called hereinlater “nano-contact portion”) is a “key” of the BMR effect. As the read head miniaturization progresses, strong GEN magnetic field is generated from the end face of the fine free layer, which results in a degradation of its thermal instability, being inconvenient and disadvantageous. Therefore, in the BMR element, it is an extremely important object to ensure the magnetic domain control and magnetic stability thereof. SUMMARY OF THE INVENTION An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a magnetoresistance effect element, particularly for a magnetic head, having BMR effect capable of achieving improved stability and sensitivity of a free layer and a magnetic domain of a nano-contact portion constituting the magnetoresistance effect element. Another object of the present invention is to also provide a magnetic head provided with such magnetoresistance effect element. These and other objects can be achieved according to the present invention, by providing, in one aspect, a magnetoresistance effect element comprising: a substrate; and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate, the pinned layer being composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and the domain stability layer including a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer. In this aspect, the free layer has the same direction of magnetization as that of the ferromagnetic layer constituting the domain stability layer. According to the magnetoresistance effect element of this aspect, the insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length is disposed between the free layer and the pinned layer, both provided with the ferromagnetic layer, so that the bottom-type magnetoresistance effect element thus obtained can perform the signal detection at high sensitivity due to the BMR effect caused by the location of the nano-contact portion. Moreover, since the domain stability layer disposed on the free layer is composed of the non-magnetic layer, one or two ferromagnetic layers and the anti-ferromagnetic layer laminated in this order from the free layer side. By this way, the free layer can be made monodomain, thus achieving and ensuring high magnetic stability and output read signal. In another aspect of the present invention, there is also provided a magnetoresistance effect element comprising: a substrate; a layer lamination structure disposed on the substrate and comprising a buffer layer, a free layer composed of a ferromagnetic layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a pinned layer and an anti-ferromagnetic layer, which are laminated in the described order on the substrate; insulating layer at the side of the layer lamination structure; and domain stability layers disposed on both side portions of the layer lamination structure through the side insulating layer, respectively, the pinned layer being composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the insulating layer, and the domain stability layer being composed of a ferromagnetic layer and an anti-ferromagnetic layer. In this aspect, the free layer has the same direction of magnetization as that of the ferromagnetic layer constituting the domain stability layer. According to the magnetoresistance effect element of this aspect, the insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length is also disposed, as in the former aspect, between the free layer and the pinned layer both provided with the ferromagnetic layer, so that the top-type magnetoresistance effect element thus obtained can perform the signal detection at high sensitivity due to the BMR effect caused by the location of the nano-contact portion. Moreover, the domain stability layers, each composed of the ferromagnetic layer and anti-ferromagnetic layer, are disposed on both side portions of the layer lamination structure achieving the BMR effect through the insulating layer, respectively, so that the high magnetic stability can be achieved and ensured. Furthermore, in both the above aspects, the ferromagnetic layer forming the free layer has a direction of magnetization normal to that of the first and second ferromagnetic layers forming the pinned layer. The first and second ferromagnetic layers forming the pinned layer have directions of magnetization which are anti-parallel to each other. The two ferromagnetic layers disposed on both sides of the insulating layer are each formed of a ferromagnetic material having spin polarization of not less than 0.5. The dimension of the nano-contact portion includes at least one of a length in the layer lamination direction and a length of lateral width, extending in a direction normal to the lamination direction, the dimension being not more than Fermi length, preferably of not more than 100 nm. In a further aspect of the present invention, there is also provided a magnetic head comprising: a magnetoresistance effect element; electrodes disposed on both sides of the magnetoresistance effect element; and a pair of shield members disposed on outside surfaces of the electrodes, respectively, the magnetoresistance effect element comprising: a substrate; and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate, wherein the pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and the domain stability layer is composed of a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer. In the still further aspect, there is also provided a magnetic head comprising: a magnetoresistance effect element; electrodes disposed on both sides of the magnetoresistance effect element; and a pair of shield members disposed on outside surfaces of the electrodes, respectively, the magnetoresistance effect element comprising: a substrate; a layer lamination structure disposed on the substrate and comprising a buffer layer, a free layer composed of a ferromagnetic layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a pinned layer and an anti-ferromagnetic layer, which are laminated in the described order on the substrate; insulating layer disposed on both side portions of the layer lamination structure; and domain stability layers disposed on both side portions of the layer lamination structure through the side insulating layer, respectively, wherein the pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the insulating layer, and the domain stability layer is composed of a ferromagnetic layer and an anti-ferromagnetic layer. In this aspect, since the bottom-type or top-type magneto-resistance effect element having high stability and sensitivity can be applied to the magnetic head, the stability of the magnetic head can be also achieved. The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIG. 1 is a sectional view of a magnetoresistance effect element of bottom-type structure, taken in a layer lamination direction thereof, according to one embodiment of the present invention; FIG. 2 is an illustration of a nano-contact portion, in an enlarged scale, of the magnetoresistance effect element of FIG. 1; FIG. 3 is a sectional view showing a domain stability layer composed of a ferromagnetic layer and an antiferromagnetic layer; FIG. 4 is a sectional view of a magnetoresistance effect element of top-type structure, taken in a layer lamination direction thereof, according to another embodiment of the present invention; and FIG. 5 is an illustration of a magnetic head utilizing the magnetoresistance effect element according to the present invention mentioned above. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a magnetoresistance effect element and a magnetic head utilizing the same according to the present invention will be described hereunder with reference to the accompanying drawings. Further, hereunder, a magnetoresistance effect element of bottom-type structure (called bottom-type magnetoresistance effect element) will be first mentioned, and a magnetoresistance effect element of top-type structure (called top-type magneto-resistance effect element) will be then mentioned, in which the “bottom-type structure” usually means a structure in which a pinned layer is formed at a lower portion of the magnetoresistance effect element in the layer lamination direction, and on the other hand, the “top-type structure” usually means a structure in which a pinned layer is formed at an upper portion of the magneto-resistance effect element. (1) Bottom-type Magnetoresistance Effect Element The bottom-type magnetoresistance effect element 10 of the present invention has a layer lamination structure such as shown in FIG. 1. The lamination structure thereof is composed of a buffer layer 2, an anti-ferromagnetic layer 3, a pinned layer 4, an insulating layer 6 provided with at least one (one or more than one) nano-contact portion 5, having a dimension of less than Fermi length, a ferromagnetic free layer 7 and a domain stability layer 8, which are laminated on a substrate (board) 1 in the described order such as shown in FIG. 1. In the above lamination structure, the pinned layer 4 is composed of a first ferromagnetic layer 4A, a non-magnetic layer 4B and a second ferromagnetic layer 4C, which are laminated in this order from the side of the anti-ferromagnetic layer 3. Further, the domain stability layer 8 is composed of a non-magnetic layer 8A, one or two ferromagnetic layers 8B (8B′, 8B″) and an-anti-ferromagnetic layer 8C, which are laminated in this order from the side of the free layer 7. The lamination structure constituting layers will be described hereunder more in detail, respectively. [Substrate] As the substrate (board) 1, there may be utilized a Si substrate, a Si oxide substrate, an AlTiC substrate or like. [Buffer Layer] The buffer layer 2 is disposed to enhance a crystalline performance of the ferromagnetic layer disposed on the buffer layer 2, and it is usually formed as Ta layer, NiCr layer, Cu layer or like through a plasma or ion beam sputtering so as to provide a thickness of 1 to 10 nm, in usual. [Nano-Contact Portion] The nano-contact portion 5 in the bottom-type magneto-resistance effect element 10 is disposed in the insulating layer 6 so as to be surrounded thereby therein. Such nano-contact portion 5 is formed from a ferromagnetic material having spin polarization of not less than 0.5, and as such ferromagnetic material, although various kinds of materials are utilized, the following ones will, for example, be listed up. Ferromagnetic Metal Group: Co (spin polarization: 0.8); Fe (spin polarization: 0.5); Ni (spin polarization: 0.8); CoFe (spin polarization: 0.6 to 0.8); NiFe (spin polarization: 0.6 to 0.8); CoFeNi (spin polarization: 0.6 to 0.8); and so on. Ferromagnetic Metalloid Group: CrO2 (spin polarization: 0.9 to 1.0); and so. Ferromagnetic Oxide: Fe3O4 (spin polarization: 0.9 to 1.0); and so. In the above ferromagnetic materials, the CoFe, CoFeNi and NiFe may be more preferable. With reference to FIG. 2, showing one nano-contact portion 5, in an enlarged scale section, constituting a portion of the magnetoresistance effect element of FIG. 1, a length d1 in the width direction thereof, i.e., a direction normal to the layer lamination direction, is set to be less than the Fermi-length. The nano-contact portion 5 is constituted so as to have a shape of circle, elliptical, rectangular (triangle, square or so) or like supposing that the magnetoresistance effect element be viewed in a plan view such as shown in FIG. 1. In this meaning, the above length d1 of the nano-contact portion 5 will be considered to be equal to the maximum length d1 in the plane in which the nano-contact portion 5 exists as viewed in the plan view of the magnetoresistance effect element 10 such as shown in FIG. 1, and accordingly, in the present invention, it will be said that the maximum length d1 of the nano-contact portion 5 is less than the Fermi length. The Fermi length being of the length d1 of the nano-contact portion 5 in its width direction is a value specific to material (specific value or characteristic value), which is different for every material constituting the ferromagnetic material forming the nano-contact portion 5. However, many kinds of such ferromagnetic materials have the Fermi length of about 60 nm to 100 nm, so that the words “less than the Fermi length” will be prescribed as “less than 100 nm” or “less than 60 nm”. In fact, Ni has the Fermi length of about 60 nm and that of Co is of about 100 nm. Furthermore, it is more desirable that the length of the nano-contact portion 5 in its width direction is less than a mean free path. Although the value of this mean free path is also a value specific to ferromagnetic materials constituting the nano-contact portions, many of them reside in a range of about 5 nm to 15 nm. Accordingly, in this meaning, the word “less than mean free path” will be prescribed substantially equivalently as “less than 15 nm” or “less than 5 nm”. In concrete examples, NiFe has a mean free path of about 5 nm and that of Co is of about 12 nm. Incidentally, it is also desirable that a length (distance) d2 of the nano-contact portion 5 in the layer lamination direction, i.e., vertical direction as viewed in the plane of FIG. 1 or 2 is also less than the Fermi length as like as the length d1. More specifically, it is desired to be prescribed as being less than 100 nm or less than 60 nm, and moreover, it is further desirable for the length d2 to be prescribed to be less than the mean free path, i.e., less than 15 nm or less than 5 nm as mentioned above. On the contrary, in a case that the lengths d1 and d2 in the width and lamination directions of the nano-contact portion 5 exceed the Fermi length, the thickness of the magnetic wall of the nano-contact portion 5 becomes large in the case that the magnetization shows an anti-parallel state, and hence, it becomes difficult for electron passing the nano-contact portion 5 to keep spin information. As a result, in this meaning too, it is desirable for the preferred embodiment of the present invention that the dimension of the nano-contact portion 5 (d1 and d2) is less than the Fermi length, and especially, in the viewpoint of well keeping the spin direction, it is less than the mean free path. Further, on the other hand, in the case where the lengths d1 and d2 in the width and lamination directions of the nano-contact portion 5 are less than the Fermi length, a thin wall section is generated to the magnetic wall section of the nano-contact portion 5. Accordingly, relative relationship in magnetization arrangement between the pinned layer 4 and the free layer 7, between which the nano-contact portion 5 is sandwiched, varies, and hence, electric resistance between the pinned layer 4 and the free layer 7 will also vary. In the case of the magnetoresistance effect element 10 of the present invention, since basically, there exists a magnetic field area, in which the electric resistance is reduced in accordance with the magnetic field even if magnetic field applying direction be changed, it will be said that the magnetoresistance effect produced there is the effect which is produced by the magnetic wall formed to the nano-contact portion 5. Herein, the magnetic wall of the nano-contact portion 5 acts as a transition region or area of two portions (i.e., two ferromagnetic layers 4C and 7 sandwiching the nano-contact portion 5) having different magnetized directions. Further, according to the present invention, the magneto-resistance effect more than 50% will be produced in accordance with the magnetized direction and magnitude of the applied magnetic field. Such nano-contact portion 5 can be manufactured with high precision by fine working means such as nano-lithography micro-fabrication. Since the magnetoresistance effect element, of the present invention, provided with such nano-contact portion 5 indicates a large MR ratio, it is considered that electrons can ballistically pass through the nano-contact portion 5 without any scattering of impurities. Further, the MR ratio mentioned above means an MR ratio (AR/R), which is defined by an electrical resistance R at a time of sufficiently large magnetic strength and an electrical resistance change AR at a time when an applied magnetic field is changed. A portion (or portions) other than the nano-contact portion 5 disposed between the two ferromagnetic layers 4C and 7 is composed of (or forms) the insulating layer 6, which is formed of, for example, an oxide such as aluminum oxide or silicon oxide or insulating material such as nitride of, for example, silicon nitride. This insulating layer 6 has its length in the lamination direction substantially the same as the length d1 in the width direction of the nano-contact portion 5. Further, as mentioned before, it may be said that one or more than one (at least one) nano-contact portions 5 are formed in the insulating layer 6 with the same thickness as that of the insulating layer 6. [Ferromagnetic Layers] In the structure mentioned above, two ferromagnetic layers disposed so as to sandwich the nano-contact portion(s) 5 therebetween is the second ferromagnetic layer 4C of the pinned layer 4 and the ferromagnetic layer forming the free layer 7. In this embodiment, these ferromagnetic layers are formed of a ferromagnetic material having the spin polarization of not less than 0.5. For this purpose, although various ferromagnetic materials may be utilized, the same or identical material as or to that for the nano-contact portion 13 will be preferably utilized. In the structure that the nano-contact portion 5 and the ferromagnetic layers adjacent to the sandwiched nano-contact portion 5 are formed of the same ferromagnetic material, the film formation and etching processing can be done with the same one ferromagnetic material and, in addition, granular structural film formation technique can be preferably utilized, thus being advantageous and effective for the manufacturing of the magnetoresistance effect element 10. [Pinned Layer] In the bottom-type magnetoresistance effect element 10 of the structure described above, the pinned layer 12 may be called “pin layer (pinned layer)”, which is disposed between the anti-ferromagnetic layer 3 and the insulating layer 6 including the nano-contact portion 5. This pinned layer 4 is composed of the first ferromagnetic layer 4A, the non-magnetic layer 4B and the second ferromagnetic layer 4C in this order from the side of the anti-ferromagnetic layer 3. The first and second ferromagnetic layers 4A and 4C constituting the pinned layer 4 may be formed of various kinds of ferromagnetic materials having the spin polarization of not less than 0.5, and CoFe, Co or like will be more preferably utilized. In such case, these two ferromagnetic layers 4A and 4B may be formed of the same material or materials different to each other, and their thicknesses are also made equal to or different from each other, generally, to about 2 to 10 nm through the plasma or ion beam sputtering. The non-magnetic layer 4B sandwiched between these ferromagnetic layers 4A and 4C is formed of a material selected from the group consisting of Ru, Rh, Ir, Cu, Ag or Au, or alloy thereof so as to have a thickness, in usual, of about 0.5 to 2 nm through the sputter deposition process. These two ferromagnetic layers 4A and 4C are spaced by the non-magnetic layer 4B so as to have their magnetizations aligned in the opposite directions. According to the function of this non-magnetic layer 4B, the magnetization of these two ferromagnetic layers 4A and 4C can be stabilized. As a result, high pinning field can be obtained and the free layer biasing point can be adjusted. Further, these ferromagnetic layers 4A and 4C and non-magnetic layer 8 may be preferably formed through plasma or ion beam sputtering. [Free Layer] In the bottom-type magnetoresistance effect element 10 of the structure mentioned above, the free layer 7 is a ferromagnetic layer (i.e., third ferromagnetic layer in this embodiment) in which magnetization is rotated in one or reverse direction in response to a magnetic field generated from recorded media bits, and it is desired to have the direction of an easy-axis magnetization parallel to the medium. This third ferromagnetic layer as the free layer 7 may be preferably formed of various materials having the spin polarization of not less than 0.5, and the material of CoFe or Co will be more preferably utilized to form it generally having its thickness of about 0.5 to 5 nm through the plasma or ion beam sputtering. [Magnetic Stability Control Layer] The domain stability layer 8 is a layer provided for controlling the stability of the magnetization direction of the free layer 7, and hence, is disposed on the ferromagnetic layer of the free layer 7 (i.e., third ferromagnetic layer). This domain stability layer 8 is composed of the non-magnetic layer 8A, one or more than one ferromagnetic layers 8B (8B′, 8B″) and the anti-ferromagnetic layer 8C in this order from the side of the free layer 7. The non-magnetic layer 8A is a layer for reducing the exchange coupling between the free layer 7 and the ferromagnetic layer 8B as viewed in FIG. 1. The non-magnetic layer 8A is formed of a material selected from the group consisting of Ru, Rh, Ir, Cu, Ag or Au, Ta, Cr, or alloy thereof so as to have a thickness, in usual, of about 0.3 to 3 nm through the plasma or ion beam sputtering. The domain stability layer 8 has a configuration in which the magnetization direction of the ferromagnetic layer 8B is the same as that of the ferromagnetic free layer 7. The ferromagnetic layer 8B includes two cases of one layer 8B′ and two layers 8B′ and 8B″. In the case of the one layer 8B′, it will be formed of CoFe, NiFe or like through the ion beam or plasma sputtering deposition so as to provide a film thickness of 1 to 5 nm, in usual. On the other hand, in the case of two layers 8B′ and 8B″, formed, in this order from the side of the non-magnetic layer 8A as shown in FIG. 3, the ferromagnetic layer 8B′ is a layer acting to make the free layer 7 as single magnetic domain through the magnetostatic coupling and is formed of CoFe, NiFe or like through the ion beam or plasma sputtering deposition so as to provide the film thickness of 1 to 5 nm, in usual. The ferromagnetic layer 8B″ is a layer, on the other hand, to generate a high exchange coupling with the antiferromagnetic layer 8C, thus the layer 8B will have its magnetization fixed. The anti-ferromagnetic layer 8C is a layer disposed on the ferromagnetic layer 8B in the lamination state shown in FIG. 1. The anti-ferromagnetic layer 8C is formed of a material selected from the group consisting of PtMn, IrMn, PtPdMn and FeMn through the ion beam or plasma sputtering so as to provide a film thickness, in usual, of about 2 to 20 nm. (2) Top-Type Magnetoresistance Effect Element The other embodiment of the magnetoresistance effect element of the present invention, as the top-type one, will be described hereunder with reference to FIG. 4 illustrating a sectional view of the layer lamination of the magnetoresistance effect element of this embodiment. The top-type magnetoresistance effect element 20 of this embodiment has an arrangement, different from that of the bottom-type one 10, in which the free layer and the pinned layer are substituted with each other in the vertical position in the layer lamination structure of FIG. 4. That is, this top-type magnetoresistance effect element 20 includes a layer lamination structure 30 comprising a buffer layer 22, a free layer 23 composed of ferromagnetic layer, an insulating layer 25 provided with one or more than one (at least one) nano-contact portions 24 each having a dimension of Fermi length, a pinned layer 26 and an anti-ferromagnetic layer 27, which are laminated on a substrate 21 in the described order. The bottom shield and eventually bottom electrode are not shown in this figure and are deposited between the substrate 21 and the buffer layer 22. The top-type magnetoresistance effect element 20 is composed of such layer lamination structure 30, side insulating layer 31 formed at both side portions of the layer lamination structure 30 and domain stability layers 40 disposed on both side portions of the layer lamination structure 30 through the side insulating layer 31, respectively. In such arrangement, the pinned layer 26 is composed of a first ferromagnetic layer 26A, a non-magnetic layer 26B and a second ferromagnetic layer 26C arranged in this order from the side of the insulating layer 25. Each of the domain stability layers 40 is composed of a ferromagnetic layer 40A and an anti-ferromagnetic layer 40B, which are laminated as layer lamination structure. Further, since the substrate 21, the buffer layer 22, the free layer 23 composed of the ferromagnetic layer, the nano-contact portion(s) 24, the insulating layer 25, the pinned layer 26 and the anti-ferromagnetic layer 27 constituting the layer lamination structure 30 of this top-type magnetoresistance effect element 20 are substantially the same, in their materials and natures, as those of the bottom-type magnetoresistance effect element 10 mentioned hereinbefore, the detail explanations thereof are omitted herein. Accordingly, the characteristic feature of the top-type magnetoresistance effect element 20 resides in that the side insulating layer 31 are formed on both side surfaces of the layer lamination structure 30 and the magnetic stability control layers 40 are also disposed on both the side portions through the insulating layer 31 as shown in FIG. 4. The side insulating layer 31 is formed of an oxide such as aluminum oxide or silicon oxide, or nitride such as silicon nitride through the plasma or ion beam sputtering. Each of the magnetic stability control layers 40, which is a layer for controlling the stability of the magnetization of the free layer 23, is composed of the ferromagnetic layer 40A and the anti-ferromagnetic layer 40B. Further, it is preferred that the ferromagnetic layer 40A constituting the domain stability layer 40 is formed of the same material as that forming the ferromagnetic layer 8B of the bottom-type magnetoresistance effect element 10 such as CoFe, NiFe or like. On the other hand, it is preferred that the anti-ferromagnetic layer 40B constituting the domain stability layer 40 is formed of the same material as that forming the anti-ferromagnetic layer 8C of the bottom-type magneto-resistance effect element 10 such as one selected from the group consisting of PtMn, IrMn, PtPdMn and FeMn, or like through the ion beam or plasma sputtering so as to provide a film thickness of 2 to 20 nm, in usual. In the embodiment of the bottom-type and top-type magnetoresistance effect elements 10 and 20 of the present invention, the two ferromagnetic layers between which the nano-contact portion is disposed have magnetization directions normal to each other. That is, the magnetization direction of the ferromagnetic layer forming the free layer 7 and that of the first and second ferromagnetic layers 4A and 4C forming the pinned layer 4 are normal to each other. Furthermore, each of the bottom-type and top-type magneto-resistance effect elements 10 and 20 of the present invention has a flat surface in form of layer so as to make easy the magnetic domain control, so that it is possible to easily and properly adjust the distribution condition of magnetization, and it is also possible to sharply keep the magnetic wall width between the ferromagnetic layers opposing to each other with the nano-contact portion being sandwiched therebetween and hence to achieve large MR ratio. However, it is not always necessary for these two ferromagnetic layers to provide a flat layer surface, and it may be possible to provide a slightly rough surface or curved surface. Furthermore, the present invention may include embodiments in which one or plural nano-contact portions 5 are arranged, and in the case where plural (more than one) nano-contact portions 5 are disposed between the free layer and the pinned layer (i.e., between two ferromagnetic layers thereof), the MR value may be slightly reduced, but, in comparison with the arrangement of the single nano-contact portion 5, the scattering of the MR values in each element could be reduced, thus easily reproducing the stable MR characteristics. [Magnetic Head] A magnetic head (magneto-resistive head) formed by utilizing the magnetoresistance effect element of the present invention of the structures and characters mentioned above can provide a large reproduced sensitivity because, by utilizing such magnetoresistance effect element, the MR ratio of more than 50% can be produced. FIG. 5 is an illustrated example of an embodiment of the magnetic head utilizing the bottom-type magnetoresistance effect element of the present invention, mentioned hereinabove, as a magnetic reproducing element. With reference to FIG. 5, the magnetic head 50 of this embodiment comprises: the magnetoresistance effect element 10 of the structure shown in FIG. 1 including the anti-ferromagnetic layer 3, the pinned layer 4, the nano-contact portion 5, the free layer 7 and the domain stability layer 8; electrodes 51 and 52 disposed outside the anti-ferromagnetic layer 3 and the domain stability layer 8; and shield members 53 and 54 both disposed further outside the electrodes 51 and 52. Reference numeral 55 shows a flow path of a sensing current. In the magnetic head 50, the magnetoresistance effect element 10 is disposed so that the film surface thereof has a vertical arrangement with respect to a recording medium 56. In the illustrated arrangement, the nano-contact portion 5 is arranged in a direction approaching the recording medium 56 from the center of the magnetoresistance effect element 10. Furthermore, in the illustrated embodiment of FIG. 5, although a horizontal magnetized film is illustrated as the recording medium 56, it may be substituted with a vertical magnetized film. The magnetoresistance effect element 10 of the embodiment shown in FIG. 5 has a width of 20 to 100 nm, and the respective layers constituting this element 10 having a thickness in the range of 0.5 to 20 nm may be optionally selected in accordance with the recording density and the required sensitivity to be utilized. Furthermore, the one or more nano-contact portions may be formed so as to provide the thickness of 2 to 20 nm. As mentioned above, according to the magnetoresistance effect element mounted to the magnetic head of the present invention, the easy axis of the free layer arranged in opposition to the recording medium formed of the horizontal magnetic film provides a direction parallel to the magnetization direction of the recording medium, and the magnetization of the easy axis is rotated in sensitive response to the magnetic field generated from the magnetization transition region of the recording medium in case of longitudinal recording or from the bit itself in case of perpendicular magnetic recording. As a result, the sensing current passing the nano-contact portion varies and the leak field of the recording medium can be sensitively read out. Moreover, the magnetoresistance effect element can indicate the magnetoresistance effect more than 50%, thus providing the magnetic head with high sensitivity and with improved stability in function. Furthermore, according to the present invention, the magnetic head may be also manufactured by utilizing the top-type magnetoresistance effect element 20 shown in FIG. 4 in substantially the same manner as mentioned above with respect to the magnetic head utilizing the bottom-type magnetoresistance effect element 10. It is to be noted that the present invention is not limited to the described embodiment and many other changes and modifications may be made without departing from the scopes of the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of The Invention The present invention relates to a magnetoresistance (or magneto-resistance) effect element particularly provided with Ballistic Magneto Resistance (BMR) effect and also relates to a magnetic head provided with such magnetoresistance effect element. 2. Relevant Art Generally, a giant magnetoresistance effect (GMR effect) is a phenomenon indicating rate of change in magnetoresistance (called herein MR ratio) which is developed or reviled in a case that electric current passes in a plane of a lamination structure of ferromagnetic layer/non-magnetic layer/ferromagnetic layer. Moreover, the magnetoresistance effect element of such GMR has been further actively studied for the development of more large MR ratio, and up to now, ferromagnetic tunnel junction and a CPP (Current Perpendicular to Plane)-type MR element, in which the current passes perpendicularly with respect to the lamination structure, have been developed, and hence, has high degree of expectation for reproducing (regenerative) element for magnetic sensor, magnetic recording element and the like. In the field of the magnetic recording technology, according to improvement of recording density, it has been a progress to make compact recording bits, and as its result, it becomes difficult to obtain a sufficient signal strength. Thus, taking such matters into consideration, it has been desired for engineers in this field to search a material having high sensitive magnetoresistance effect and develop or revile an element indicating a large MR ratio. Recently, there have been reported, as material indicating MR ratio of more than 100%, “magnetic micro contact” which is formed by butting two needle-like nickel (Ni) as shown, for example, in a document of “Physical Review Letters, vol. 82, p2923 (1999), by N. Garcia, M. Munoz, and Y. -W. Zhao” (Document 1). This magnetic micro contact is manufactured by butting two ferromagnetic materials arranged in form of needle or in form of triangle. More recently, there has been developed a magnetic micro contact in which two fine Ni wires are arranged in T-shape and micro column is grown at a contact portion of these wires by electro-deposition method (for example, refer to a document of “Appl. Phys. Lett. Vol. 80, p1785 (2002), by N. Garcia, G. G. Qian, and I. G. Sveliev” (Document 2). It is considered that an extremely high MR ratio developing such element is based on spin transport of a magnetic area existing in the magnetic nano contact formed between two ferromagnetic layers having magnetized directions in anti-parallel to each other. It is considered that, in the magnetoresistance effect element utilizing the magnetic nano contact having such characteristics, since electrons pass without receiving any scattering or diffusion (i.e., pass ballistically), such magnetoresistance effect element is called BMR element (Ballistic Magneto Resistance element). In addition, more recently, there has also been reported a magnetoresistance effect element having such magnetic nano contact. For example, in Japanese Patent Laid-open (KOKAI) Publication No. 2003-204095 (Document 3), there is reported a magnetoresistance effect element composed of first ferromagnetic layer/insulating layer/second ferromagnetic layer, in which the first ferromagnetic layer is connected to the second ferromagnetic layer at a predetermined portion of the insulating layer, the magnetoresistance effect element being provided with a hole having the maximum diameter of less than 20 nm. Furthermore, in Japanese Patent Application National Publication (Laid-open) No. HEI 11-510911 (Document 4), there is reported a magneto-resistance effect element composed of two magnetic layers connected to each other through a narrow segment having a width of about 100 nm. However, in consideration of application of a BMR element to a magnetic head, a dimension of a free layer sensitive to magnetic field leaking from a surface of a medium is made small such as, for example, to several tens nm. In a case of recording density of 1 Tbits/in 2 , a read head of 40 to 50 nm width is required, and in a case of a BMR element capable of realizing an extremely high MR ratio, a structure of a magnetic domain of the magnetic nano contact (called hereinlater “nano-contact portion”) is a “key” of the BMR effect. As the read head miniaturization progresses, strong GEN magnetic field is generated from the end face of the fine free layer, which results in a degradation of its thermal instability, being inconvenient and disadvantageous. Therefore, in the BMR element, it is an extremely important object to ensure the magnetic domain control and magnetic stability thereof.
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<SOH> SUMMARY OF THE INVENTION <EOH>An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a magnetoresistance effect element, particularly for a magnetic head, having BMR effect capable of achieving improved stability and sensitivity of a free layer and a magnetic domain of a nano-contact portion constituting the magnetoresistance effect element. Another object of the present invention is to also provide a magnetic head provided with such magnetoresistance effect element. These and other objects can be achieved according to the present invention, by providing, in one aspect, a magnetoresistance effect element comprising: a substrate; and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate, the pinned layer being composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and the domain stability layer including a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer. In this aspect, the free layer has the same direction of magnetization as that of the ferromagnetic layer constituting the domain stability layer. According to the magnetoresistance effect element of this aspect, the insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length is disposed between the free layer and the pinned layer, both provided with the ferromagnetic layer, so that the bottom-type magnetoresistance effect element thus obtained can perform the signal detection at high sensitivity due to the BMR effect caused by the location of the nano-contact portion. Moreover, since the domain stability layer disposed on the free layer is composed of the non-magnetic layer, one or two ferromagnetic layers and the anti-ferromagnetic layer laminated in this order from the free layer side. By this way, the free layer can be made monodomain, thus achieving and ensuring high magnetic stability and output read signal. In another aspect of the present invention, there is also provided a magnetoresistance effect element comprising: a substrate; a layer lamination structure disposed on the substrate and comprising a buffer layer, a free layer composed of a ferromagnetic layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a pinned layer and an anti-ferromagnetic layer, which are laminated in the described order on the substrate; insulating layer at the side of the layer lamination structure; and domain stability layers disposed on both side portions of the layer lamination structure through the side insulating layer, respectively, the pinned layer being composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the insulating layer, and the domain stability layer being composed of a ferromagnetic layer and an anti-ferromagnetic layer. In this aspect, the free layer has the same direction of magnetization as that of the ferromagnetic layer constituting the domain stability layer. According to the magnetoresistance effect element of this aspect, the insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length is also disposed, as in the former aspect, between the free layer and the pinned layer both provided with the ferromagnetic layer, so that the top-type magnetoresistance effect element thus obtained can perform the signal detection at high sensitivity due to the BMR effect caused by the location of the nano-contact portion. Moreover, the domain stability layers, each composed of the ferromagnetic layer and anti-ferromagnetic layer, are disposed on both side portions of the layer lamination structure achieving the BMR effect through the insulating layer, respectively, so that the high magnetic stability can be achieved and ensured. Furthermore, in both the above aspects, the ferromagnetic layer forming the free layer has a direction of magnetization normal to that of the first and second ferromagnetic layers forming the pinned layer. The first and second ferromagnetic layers forming the pinned layer have directions of magnetization which are anti-parallel to each other. The two ferromagnetic layers disposed on both sides of the insulating layer are each formed of a ferromagnetic material having spin polarization of not less than 0.5. The dimension of the nano-contact portion includes at least one of a length in the layer lamination direction and a length of lateral width, extending in a direction normal to the lamination direction, the dimension being not more than Fermi length, preferably of not more than 100 nm. In a further aspect of the present invention, there is also provided a magnetic head comprising: a magnetoresistance effect element; electrodes disposed on both sides of the magnetoresistance effect element; and a pair of shield members disposed on outside surfaces of the electrodes, respectively, the magnetoresistance effect element comprising: a substrate; and a layer lamination structure disposed on the substrate and comprising a buffer layer, an anti-ferromagnetic layer, a pinned layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a free layer composed of a ferromagnetic layer and a domain stability layer, which are laminated in the described order on the substrate, wherein the pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the anti-ferromagnetic layer, and the domain stability layer is composed of a non-magnetic layer, a ferromagnetic layer and an anti-ferromagnetic layer disposed in this order from the side of the free layer. In the still further aspect, there is also provided a magnetic head comprising: a magnetoresistance effect element; electrodes disposed on both sides of the magnetoresistance effect element; and a pair of shield members disposed on outside surfaces of the electrodes, respectively, the magnetoresistance effect element comprising: a substrate; a layer lamination structure disposed on the substrate and comprising a buffer layer, a free layer composed of a ferromagnetic layer, an insulating layer including at least one nano-contact portion having a dimension of not more than Fermi length, a pinned layer and an anti-ferromagnetic layer, which are laminated in the described order on the substrate; insulating layer disposed on both side portions of the layer lamination structure; and domain stability layers disposed on both side portions of the layer lamination structure through the side insulating layer, respectively, wherein the pinned layer is composed of a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer disposed in this order on the side of the insulating layer, and the domain stability layer is composed of a ferromagnetic layer and an anti-ferromagnetic layer. In this aspect, since the bottom-type or top-type magneto-resistance effect element having high stability and sensitivity can be applied to the magnetic head, the stability of the magnetic head can be also achieved. The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.
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20040702
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20060627
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20050331
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62237.0
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EVANS, JEFFERSON A
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MAGNETORESISTANCE EFFECT ELEMENT COMPRISING NANO-CONTACT PORTION NOT MORE THAN A FERMI LENGTH, AND MAGNETIC HEAD UTILIZING SAME
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UNDISCOUNTED
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ACCEPTED
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10,882,381
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ACCEPTED
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Multicolor-printer and method of printing images
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A multicolor-printer has at least a first and a second print station, first and second optical sensors and a surface recordings comparator. The first and second print stations are arranged to print images on a surface of a moving recording medium. The first and second optical sensors view, at the first and second print stations, an area of the recording medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively. A storage is arranged to store the first surface recording. The surface recordings comparator is arranged to test, during the recording medium movement, for correspondence of second surface recordings with the stored first surface recording. The printer is arranged to repeatedly, within one image, register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings.
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1. A multicolor-printer, comprising: at least a first and a second print station arranged to print images on a surface of a moving recording medium; first and second optical sensors viewing, at the first and second print stations, an area of the recording medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively; a storage arranged to store the first surface recording; a surface recordings comparator arranged to test, during the recording medium movement, for correspondence of second surface recordings with the stored first surface recording; wherein the printer is arranged to repeatedly, within one image, re-register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings. 2. The multicolor-printer of claim 1, wherein the relation of the first surface recording to the first print station's image printing is such that the first surface recording is taken: (a) when the first print station's prints a certain raster line of its image, or (b) at a predetermined distance before the first print station prints a certain raster line. 3. The multicolor-printer of claim 1, comprising at least one movement signal generator generating signals representing recording medium movement, the first and second print stations being arranged to form their images by image dots on raster lines defined on the basis of the movement signals, between repeated re-registrations. 4. The multicolor-printer of claim 3, arranged to repeat the registration of the image dots of the second print station to the ones of the first print station after a predefined number of raster lines. 5. The multicolor-printer of claim 3, comprising print-station-individual movement signal generators, and being arranged to base the definition of the image dots of the first print station on the first print station's movement signals and of the image dots of the second print station on the second print station's movement signals. 6. The multicolor-printer of claim 3, comprising at least one movement signal generator arranged to use at least two subsequent medium surface recordings recorded by the same optical sensor, compare them, determine a shift between them and provide a movement signal related to the shift determined. 7. The multicolor-printer of claim 3, comprising a recording medium conveyor equipped with an encoder forming the movement signal generator. 8. The multicolor-printer of claim 1, wherein the optical sensors comprise two-dimensionally extended sensor-cell arrays. 9. The multicolor-printer of claim 1, wherein the optical sensors are charge-coupled devices. 10. The multicolor-printer of claim 1, wherein the printer is an ink-jet printer. 11. The multicolor-printer of claim 1, wherein the printer is a page-width printer. 12. The multicolor-printer of claim 1, wherein the printer is a large-format printer. 13. The multicolor-printer of claim 1, comprising at least one further downstream print station with a further optical sensor to obtain a further surface recording and arranged to treat the further surface recording and register the image of the further downstream print station to the image of the first print station in a manner analogous to the second surface recording and the second print station. 14. A multicolor-printer, comprising: at least a first and a second print station arranged to print images on a surface of a moving recording medium; first and second optical sensors viewing, at the first and second print stations, an area of the recording medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively; a storage arranged to store the first surface recording; a surface recordings comparator arranged to test, during the recording medium movement, for correspondence of second surface recordings with the stored first surface recording; at least one movement signal generator generating signals representing recording medium movement; wherein the printer is arranged to repeatedly, within one image, re-register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings, and wherein, between repeated re-registrations, the first and second print stations are arranged to form their images by image dots on raster lines defined on the basis of the movement signals. 15. A method of printing images onto each other on a surface of a moving recording medium using a printer having at least a first and a second print station and first and second optical sensors viewing, at the first and second print stations, an area of the recording medium surface, comprising: taking a first surface recording at the first print station and relating it to a raster line of the image printed by the first print station; taking, at the second print station and during the recording medium movement, second surface recordings and testing for correspondence of the second surface recordings with the first surface recording; registering, in response to a correspondence found between one of the second surface recordings and the first surface recording, a corresponding raster line of the image printed by the second print station to the raster line of the image printed by the first print station, wherein the activities of taking a first surface recording, taking second surface recordings, testing for correspondence, and registering a corresponding raster line of the image are repeated so that, within one image, repeated re-registrations are performed. 16. The method of claim 15, comprising generating movement signals representing recording medium movement, forming the images of the first and second print stations by image dots defined by the movement signals, and forming the images, between repeated re-registrations, by image dots on raster lines defined on the basis of the movement signals. 17. The method of claim 16, wherein the registering of the image dots of the second print station to the ones of the first print station is repeated after a predefined number of image dots. 18. The method of claim 16, further comprising: generating print-station-individual movement signals; basing a definition of the image dots of the first print station on the first print station's movement signals and of the image dots of the second print station on the second print station's movement signals. 19. The method of claim 16, comprising generating the movement signals by means of at least one of the optical sensors based on recording at least two subsequent medium surface recordings by the same optical sensor, comparing them, determining a shift between them and providing a movement signal related to the shift determined. 20. A method of printing images onto each other on a surface of a moving recording medium using a printer having at least a first and a second print station and first and second optical sensors viewing, at the first and second print stations, an area of the recording medium surface, and at least one movement signal generator generating signals representing recording medium movement, comprising: taking a first surface recording at the first print station and relating it to a raster line of the image printed by the first print station; taking, at the second print station and during the recording medium movement, second surface recordings and testing for correspondence of the second surface recordings with the first surface recording; registering, in response to a correspondence found between one of the second surface recordings and the first surface recording, a corresponding raster line of the image printed by the second print station to the raster line of the image printed by the first print station, wherein the activities of taking a first surface recording, taking second surface recordings, testing for correspondence, and registering a corresponding raster line of the image are repeated so that, within one image, repeated re-registrations are performed, and, wherein, between repeated re-registrations, the images are formed by image dots on raster lines defined on the basis of the movement signals.
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FIELD OF THE INVENTION The present invention relates to a multicolor-printer and a method of printing images. BACKGROUND OF THE INVENTION Multicolor printers produce images which are composed of a plurality of different single-color images. The quality of the final multicolor image depends, i.a., on the registration accuracy of the single-color images. With the increasing resolution of modern printers the registration accuracy has become an issue of interest. Different multicolor printer types are known. Ink-jet printers have at least one print head from which droplets of ink are directed towards a print medium. Within the print head the ink is contained in a plurality of channels. Pulses cause the droplets of ink to be expelled as required from orifices or nozzles at the end of the channels. These pulses are generated e.g. by thermal components in thermal ink-jet print heads or by piezo-electric elements in drop-on-demand print heads. Ink-jet printers of the carriage type have a print head for each color. The print heads are mounted on a reciprocating carriage. Full-width or page-width ink-jet printers have, for each color, an array of nozzles extending across the full width of the print medium which is moved past the nozzle arrays. Each nozzle array is part of a print station which forms one single-color image or a part of it. Each print station produces its own single-color image on the print medium as it moves past the print stations. Each single-color image is composed of a plurality of closely spaced image dots, wherein single-color dots are superimposed to form a dot of a required color. The superimposed single-color dots may be printed onto each other or in a side-by-side relation. The recording medium may be paper or any other suitable substrate to which the ink adheres. In known color xerographic systems, instead of the nozzle arrays, a plurality of print bars are provided which produce an electrostatic charge image on a recording medium. The print bars are selectively energized to create successive charge images, one for each color. The print bars may, for example, be LED print bars which produce the charge image an a previously charged photoreceptive surface. Each LED print bar is associated with a development system, which develops a latent image of the last charge image or exposure without disturbing previously developed images. The fully developed color image is then transferred to an output sheet, e.g. paper or the like. It is also possible to form electrostatic charge images directly on the output sheet which is then exposed to a toner of the respective color to produce a visible image. To register single-color images for forming a multicolor image, encoder arrangements are utilized which determine the advance of the recording medium during the print process. Optical encoder systems are known in which an optical sensor is responsive to encoder marks. In page-width printers the recording medium is, for example, moved by a conveying belt which is driven by rollers or pulleys. The movement of the belt with the recording medium may be detected by a single rotary encoder which is mounted on one of the rollers or pulleys. The advance of the belt is controlled by advance information represented by the rotary encoder signals. It is also known to place the encoder marks on the belt. U.S. Pat. No. 5,526,107 is directed to a system and method for duplex printing wherein two images are registered at corresponding locations on the two sides of a print medium. The positions of the printed images relative to each other are synchronized by mechanical means or by detecting the position of special marks or an area of the image itself. It is mentioned that color-to-color registration may be achieved using a similar synchronization technique. U.S. Pat. No. 4,804,979 discloses an electrostatic color printer with several print stations. Encoding marks are printed on the recording medium (which is paper). Each print station has its own optical sensor responsive to the encoding marks to detect and correct for variations of the recording medium to obtain registration of the single-color images. The registration is checked every 50 raster lines and brought into exact registration, if necessary. EP 0 729 846 B1 discloses a high-speed ink-jet printing press in which registration marks are printed on the print medium. The registration marks are used, at low speeds, for aligning the recording stations, and, at high speeds, for registering the single-color images. SUMMARY OF THE INVENTION A first aspect of the invention is directed to a multicolor-printer. It comprises at least a first and a second print station, first and second optical sensors and a surface recordings comparator. The first and second print stations are arranged to print images on a surface of a moving print medium. The first and second optical sensors view, at the first and second print stations, an area of the print medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively. A storage is arranged to store the first surface recording. The surface recordings comparator is arranged to test, during the print medium movement, for correspondence of second surface recordings with the stored first surface recording. The printer is arranged to repeatedly, within one image, re-register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings. According to another aspect, a multicolor-printer is provided which comprises at least a first and a second print station, first and second optical sensors, a surface recordings comparator and at least one movement signal generator. The first and second print stations are arranged to print images on a surface of a moving print medium. The first and second optical sensors view, at the first and second print stations, an area of the print medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively. A storage is arranged to store the first surface recording. The surface recordings comparator is arranged to test, during the print medium movement, for correspondence of second surface recordings with the stored first surface recording. The movement signal generator generates signals representing recording medium movement. The printer is arranged to repeatedly, within one image, re-register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings. Between repeated re-registrations, the first and second print stations are arranged to form their images by image dots on raster lines defined on the basis of the movement signals. According to another aspect, a method is provided of printing images onto each other on a surface of a moving print medium using a printer having at least a first and a second print station and first and second optical sensors viewing, at the first and second print stations, an area of the print medium surface. The method comprises recording a first surface recording at the first print station and relating it to a raster line of the image printed by the first print station; recording second surface recordings at the second print station and during the print medium movement, and testing for correspondence of the second surface recordings with the first surface recording; registering, in response to a correspondence found between one of the second surface recordings a corresponding raster line of the image printed by the second print station to the raster line of the image printed by the first print station. The activities of taking a first surface recording, taking second surface recordings, testing for correspondence, and registering a corresponding raster line of the image are repeated so that, within one image, repeated re-registrations are performed. According to another aspect, a method is provided of printing images onto each other on a surface of a moving print medium using a printer having at least a first and a second print station and first and second optical sensors viewing, at the first and second print stations, an area of the print medium surface. The method comprises recording a first surface recording at the first print station and relating it to a raster line of the image printed by the first print station; recording second surface recordings at the second print station and during the print medium movement, and testing for correspondence of the second surface recordings with the first surface recording; registering, in response to a correspondence found between one of the second surface recordings a corresponding raster line of the image printed by the second print station to the raster line of the image printed by the first print station. The activities of taking a first surface recording, taking second surface recordings, testing for correspondence, and registering a corresponding raster line of the image are repeated so that, within one image, repeated re-registrations are performed. Between repeated re-registrations, the images are formed by image dots on raster lines defined on the basis of the movement signals. Other features are inherent in the disclosed products and methods or will become apparent to those skilled in the art from the following detailed description of embodiments and its accompanying drawings. DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example, and with reference to the accompanying drawings, in which: FIG. 1 is a schematic view of functional components of a multicolor-printer; FIG. 2 illustrates a combination of different single-color dots to form multicolor dots; FIG. 3 illustrates the appearance of an accumulated error when single-color images with slightly different dot spacing are overlaid; FIG. 4 is a schematic view of an optical sensor; FIG. 5 illustrates a registration of two single-color images by different “snap shots” of an advancing print process; FIG. 6 shows exemplary surface recordings taken at a first and a second print station of FIG. 5, used in the registration of the single-color images; FIG. 7 shows exemplary surface recordings similar to FIG. 6, but subsequently taken at one print station to provide a movement signal; FIG. 8 is a schematic view of a printer similar to FIG. 1, illustrating two alternative embodiments in which the movement signal is generated by encoders. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of an embodiment of a multicolor printer. Prior to the detailed discussion of FIG. 1, some items of the embodiments will be discussed. Printing of a multicolor (or full-color) image is based on what is called “color separation”: The multicolor image is composed of a number of basic color images (e.g. using CMY or CMYB with C=cyan, M=magenta, Y=yellow, B=black) which are individually printed in an aligned manner. Although, in principle, the different colors could be provided by a single print station, in the preferred embodiments the single-color images are generated by different print stations. In some of the embodiments, the print stations are arranged spatially separated along the path of movement of the recording (or print) medium. They are in the form of linear arrays or elongated bars extending perpendicularly to the recording medium's direction of movement. In some embodiments, there is one print station for each basic color so that each print station produces a complete single-color image. To increase the variety of printable colors, the ink saturation and/or the resolution, some embodiments are provided with two or more print stations of the same color. Different embodiments utilize different methods of transferring an image to the recording medium. In ink-jet printers and some xerographic printers the colors are directly transferred by liquid inks or toners to the recording medium (which may be, for example, paper, photo paper, a transparency, etc.), In other color xerographic systems the full-color image is first produced on a recording medium in the form of a photoreceptive surface, the image is then transferred to the print medium e.g. the paper. In the embodiments the recording medium is moved past the print stations, e.g. by a recording medium conveyor. The conveyor is, for example, a belt conveyor or a cylindrical drum. The (main) direction of the recording medium movement is also called “advance direction”. In some embodiments the movement is a continuous movement, in other embodiments the movement is stepwise. The print stations print their single-color images during the movement of the recording medium. The expression “during the movement” is meant herein in a general sense covering also the case of a stepwise movement in which the recording medium may actually be at rest when a print station prints e.g. one raster line (or group of raster lines), and is then moved to the next raster line (or group of raster lines). Owing to the spatial distance between the print stations it takes some time until a certain point of the recording medium is moved from the first to print station to the second (and further downstream) print stations. Consequently, if the different print stations are to print onto this point in an aligned manner, their printing has to be performed in a time-shifted manner. The time-shift corresponds to the distance between the print heads divided by the (mean) velocity of the recording medium. The process of aligning the different single-color images—printed in the time-shifted manner—onto each other is also called “registering the images”. If the recording medium velocity is constant, the variable “time” is suitable for describing the interplay of the different print stations in a simple manner. Therefore, this description is used herein. Cases of varying velocity may also be correctly described, if one thinks of the variable “time” as the printer's “intrinsic time” which runs proportionally to the recording movement velocity. The registration process is described in terms of “a first and a second print station”. Typically, the printer has more than two print stations. The “first print station” may be thought of the most upstream print station, and the “second print station” may be thought of any one of the print stations downstream of it. In the embodiments, an optical sensor is associated with each print station. Preferably, it is attached to the print station in a mechanically fixed relationship to the print head such that the relative position of sensor and print head is equal for all print stations. Each optical sensor views an area of the recording medium surface at its respective print station and, if required, records an image of it, called “surface recording”. The surface recordings are used in the registration procedure since they enable a certain point of the recording medium, which is indicative of where the first print station printed a certain section (e.g. certain raster lines) of its image, to be recognized by the downstream print stations, as will be explained below. In some of the embodiments, recognizing a certain point of the recording medium requires that something actually be printed at this point. However, in the more preferred embodiments, a certain point of the recording medium can also be recognized if nothing has been printed on it, since the optical sensors are sufficiently sensitive and have sufficient resolution to detect a pattern on the recording medium's surface, which is typically irregular. The detected pattern is therefore enough characteristic to enable unique surface identification and recognition of the point. For example, paper usually has such a pattern structure due to its fiber content. Therefore, in some embodiments the optical detectors view a region outside the fiducial print area, but in other embodiments they may view an area within it (since color on the surface pattern often does not destroy its recognizability). In some of the embodiments the optical sensors are two-dimensionally extended sensor-cell arrays, for example CCDs (charge coupled devices). In embodiments in which the optical sensors are laterally accurately aligned and no lateral shifts of the recording medium appear, one-dimensional photosensor arrays can also be used. Suitable optical sensors are, for example, described in U.S. Pat. No. 6,118,132 (there for measuring the velocity, displacement and strain of a moving surface or web of material). The first surface recordings are obtained in a manner related to the first print station's image printing. “Related” means that recording the surface image and printing take place in defined distance or time relationship to a certain section of the image printed by the first print station, e.g. a certain raster line of this image. In some embodiments, recording the surface image and printing the certain raster line take place at the same time. In other embodiments, the surface image is recorded at a small distance before that section of the image (e.g. the certain raster line) to which the recording is related. A storage is provided which arranged to store the first surface recording. The stored surface recording of the first print station and the surface recordings of the downstream print stations are compared by a surface recordings comparator. The comparator tests, during the recording medium movement, for correspondence of a downstream (e.g., the second) print station's surface recordings with the first surface recording. Some embodiments also enable subsequent surface recordings of one and the same print station to be compared, from which a recording medium movement signal can be derived. In some of these embodiments, a separate comparator is provided for this “local” comparison, in others the comparator for comparing recordings of different print stations is arranged to also carry out the local comparisons. In some embodiments, the comparator is part of a (typically digital) optical-sensor controller. In other embodiments, the comparator is a programmed processors, digital circuit or analog circuit dedicated to comparing surface recordings and finding corresponding ones. In still other embodiments a printer controller (typically a specialized micro-computer) which controls the print operation is programmed to also carry out the task of comparing and finding correspondences; the “comparator” is the programmed controller with the part of the program implementing the comparator functionality. In the embodiments, finding that two compared recordings represent the same surface area of the recording medium is called a “correspondence”. Although not excluded, generally two recordings which represent the same surface area will not be strictly identical. Rather, owing to limited resolution and sensitivity, such two recordings may slightly differ from each other. Furthermore, some embodiments also enable two recordings whose surface images are shifted relative to each other to be recognized as representing the same surface area. In these embodiments, the amount of shifting is also provided by the comparator and used in the registration process. The information provided by the optical sensor and the comparator used to register the images is also called “registration signal”. In the embodiments, the printer is arranged to repeatedly register, within one image, raster lines of the image printed by the second print stations to raster lines of the image printed by the first one in response to correspondences found between the surface recordings. At the first print station, a surface image is recorded in a manner related to the first print station's printing action. For example, a surface image is recorded by the first optical detector a certain time interval before the first print station prints the section of its image to which the surface recording relates; this section may be, for example, a certain raster line of the first print station's single-color image. The certain time interval corresponds to a certain advance from the recorded point of the recording medium surface to the related raster line. In order to register raster lines of the second image onto the first one, the second print station's optical detector then permanently records surface images during the advance of the recording medium and compares them with the recorded first surface image. A correspondence found between one of the second recordings and the first recording indicates that the recording medium now is in a position relative to the second print station's print head which corresponds to the position the recording medium had relative to the first print station's print head when the raster line of the first image was printed (apart from a possible shift of the recordings within the optical detectors, as mentioned above). The second print head then prints, in the same related manner (but taking into account the possible shift of the recordings), a corresponding raster line of its single-color image. For example, it prints the related raster line after the same time interval (or distance) as the one of the first print station (corrected by the possible shift of the recordings). Thus, the single-color images are registered. Further downstream print heads register their images to the first image in a corresponding way. In some of the embodiments with two-dimensional optical detectors, not only relative shifts between the recorded surface images in the advance direction can be detected, but also shifts in the lateral direction (i.e. the direction perpendicular to it). A lateral shift indicates that the recording medium was subjected to a lateral displacement between the first and second two print stations. The lateral displacement information is included in the registration process, e.g. by laterally counter-shifting the second single-color image. FIG. 2 illustrates a part of a printed multicolor image which is composed of four different single-color images. In some of the embodiments, the images are formed by dots 25 which are arranged on a dot raster or grid with constant dot spacing. The dot density of the grid is usually given in the unit dots per inch (dpi). The higher the density, the higher is the resolution of the printed image. Typical resolutions are 300 dpi, 600 dpi, 1200 dpi or even higher, corresponding to 85 mm, 42 mm and 21 mm dot spacing, respectively. Each of the dots 25 is correspondingly composed of four basic-color dots 21, 22, 23, 24 which are subsequently applied by the different print stations. The basic-color dots 21, 22, 23, 24 are closely positioned side-by-side or, in some embodiments, partly or completely overlapping so that they optically merge to a full-color dot 25 of the desired mixed color. A side-by-side arrangement of the basic-color dots 21, 22, 23, 24 can be considered as a small “intended misalignment”; the registration process is arranged such that this intended misalignment is achieved. A “raster line” 26 is a line of dots perpendicular to the advance direction. Incidentally, a dot does not require to be actually printed; it may rather be thought of as a virtual print position which can be with or without ink on it. It could also be mentioned that the full-color dots are often called “picture elements” (pixels) to differentiate them from the single-color dots, but herein both are referred to as “dots”. Various intensities may be achieved by techniques such as halftoning, or by printing dots with different sizes. In some embodiments, the registration procedure described above (based on a comparison of surface recordings of the first and second print stations) is carried out for each raster line. This ensures optimum registration accuracy, but requires considerable processor and storage performance for storing and analyzing a large number of surface recordings. Therefore, in other embodiments, the registration procedure is not carried out for each raster line. A movement signal generator generates signals representative of the recording medium movement. These signals define the positions of the raster lines (or the timing of printing the raster lines) to be printed by the individual print stations after the registration procedure has been carried out for a certain raster line. However, a definition of dot positions based on movement signals is generally not free of systematic errors. Therefore, if too many raster lines are printed only based on movement signals, the systematic error may accumulate to form a considerable cumulated error. This is illustrated in FIG. 3 in which each raster line is represented by one dot. The upper line of dots represent the longitudinal positions of the raster lines printed by the first print station, and the lower line of dots represent the longitudinal positions of the raster lines printed by the second print station. Time is running from right to left. A registration procedure was carried out for the first raster line printed, therefore the rightmost dots of the two print stations are aligned in the longitudinal direction. The printing of the subsequent raster lines is triggered by the movement signals. It is assumed that print-station-individual movement signals are used, and that the movement signal used by the first print station has a period Δt1, and the one used by the second print station has a slightly different period Δt2 (Δt2=(1+ε)Δt1), due to systematic errors in the print-station-individual generation of the movement signals. After N dots this slightly different period accumulates to a cumulated error N·ε. The assumption that the movement signals' periods of the different print stations are different is only illustrative; similar errors may occur if the same movement signal is used for all print stations, for example if the recording medium's movement is not accurately represented by the (then common) movement signal (for example, this may be the case if the print paper is displaced or stretched). In order to avoid the errors in dot positioning from accumulating into large cumulated errors, in some of the embodiments the printer is arranged to repeatedly register the raster lines of the second print station to the ones of the first print station based on comparing the recordings of the first and second optical sensors and finding correspondences between them, as explained above. The re-registration is, for example, repeated after a predefined number of image dots (or raster lines) printed by the first print station. The predefined number may depend on the performance of the processor and memory and the magnitude of the systematic error. A typical predefined number may be in the interval between three and ten; in an example described below the number is five. In some of the embodiments, the positioning of the image dots (raster lines) is based on a movement signal which is common for all print stations. As mentioned above, a common movement signal is usually not aware of paper displacement or stretching or the like. In other embodiments, each print station uses a print-station-individual movement signal, i.e. a movement signal obtained by a measurement of the recording medium movement in the vicinity of the respective print station. Such print station-individual movement signals represent the local recording medium movement and are therefore aware of paper displacement, stretching etc. However, the calibrations of the individual movement signal generators may be different, so that they provide slightly different signals for one and the same movement, as explained above. Repeated registration (also called re-registration) prevent such errors from accumulating. This repeated registration may be performed by repeatedly adjusting the movement signal so that a raster line of the second print station becomes coincident with the corresponding one the first print station, also called “synchronization”. The repeated adjustment of the movement signal is, for example, achieved by influencing the movement signal generator to perform the required signal shift or by shifting (delaying or advancing) the movement signals by the required amount. In some of the embodiments, the optical sensors with the comparator(s) are not only used to provide the information on which the registration (including the re-registration) is based (i.e. the “registration signals”), but at least one of the optical sensors, and preferably all of them, also act as movement signal generator. The movement signal generation is also based on a comparison of recorded surface images, as in the registration signal generation described above, but the two surface images compared are images recorded by one and the same the optical sensor rather than by sensors at two different print stations. The movement signal generation is based on recording at least two subsequent medium surface images by the same optical sensor, comparing them, determining a spatial shift between them and providing a movement signal representative of the spatial shift determined, i.e. the recording medium advance between the two recordings. Preferably, the movement signal is in the form of clock signals, wherein the clock signal period corresponds to a certain advance of the recording medium. For example, an advance of one longitudinal dot distance may be represented by one clock signal (i.e. by one clock pulse) or several clock signals (i.e. by several clock pulses). In the movement signal generation, the optical sensor and the corresponding comparator operate in a print-station-local manner. Owing to this, and to the fact that only one previous surface recording is stored, the performance requirements are generally lower for the movement signal generation than for the registration signal generation. Both signal generation modes may be simultaneously used, i.e. the registration signals and the movement signals may be simultaneously generated. For example, a certain surface recording may be locally used to provide the movement signal, and may also be included in the comparison between recordings of different print stations to provide the registration signal. In some embodiments one comparator performs all the processing to provide the registration and the movement signals. In other embodiments, each optical sensor used to provide movement signals is equipped with its own comparator which generates the movement signal of the associated print station. In embodiments in which only a common movement signal is required, it is sufficient that only one of the optical sensors is used for the movement signal generation. In embodiments with print-station-individual movement signals, all the optical sensors are used for the movement signal generation and provide their associated print station with a print-station-individual movement signal indicative of the local recording medium movement. There are other techniques of providing movement signals which are based on encoders, i.e. on encoder patterns at members of the printer which move or rotate together with the recording medium and (usually optical) sensors responsive to the moving encoder pattern. In some of the embodiments, a recording medium conveyor which advances the recording medium (e.g. a belt arrangement which advances the print paper) is equipped with a co-moving encoder pattern, for example, arranged at the edge of the belt. In some of these embodiments, one encoder pattern sensor is provided to generate a common movement signal for all print stations. In other embodiments, each print station is equipped with its own encoder pattern sensor to obtain a print-station-individual movement signal indicative of the local conveyor movement. Still other embodiments have a rotary encoder coupled to the recording medium conveyor, for example, a rotating shaft of the conveyor. The rotary encoder generates a common movement signal for all print stations. Returning now to FIG. 1, a multicolor printer has several (here: four) successively arranged print stations 1. A conveyor belt 2 is arranged beneath the print stations 1, guided by two rollers 3, wherein at least one of the rollers 3 is driven by an advance mechanism in an advance or longitudinal direction 4 during the printing process. The belt 2 conveys on its outer surface 5 a recording medium 6, e.g. a paper sheet, which is moved during printing past the print stations 1. The printer is a large-format page-width printer, e.g. an ink-jet printer. Its print-width is, in one embodiment, about 24 inches or 610 mm (for A1 and ANSI D paper formats). Other embodiments have a larger print width, for example, in the range of 30-40 inches or 760-1020 mm (for A0, ISO BO and ANSI E paper formats), or even larger than 40 inches or 1020 mm (for larger paper formats). Each print station 1 extends in a lateral direction 7 normal to the advance direction 4 across the width of the belt 2. Owing to the successive arrangement of the print stations, when the print medium 6 is conveyed, a certain point of it successively passes the individual print stations 1. In order to produce a multicolor image 8 in which the single-color images are aligned or “registered”, the print stations produce their single-color images in a timely shifted manner which compensates for the fact that a point of the paper does not pass all the print stations 1 simultaneously, but only successively. Each print station 1 is provided with an optical sensor 12 which includes a photosensor array 14 arranged to view a surface area 13 of the recording medium 6. Since the optical sensor 13 is at rest and the recording medium 6 is moved, the viewed area 13 of the recording medium surface constantly changes. Each optical sensor 12 is attached to its print station 1 in a fixed mechanical relationship so that the optical sensor's longitudinal and lateral positions represent the print station's position to which it is attached, apart from a constant offset vector describing the relative position of the optical sensor 12 and its print station 1 in the longitudinal and lateral directions. When the print station's position changes, e.g. due to thermal expansion, the sensor arrangement's position is therefore correspondingly changed. The offset vectors are either accurately known or are designed to be identical (with a certain accuracy) for all print stations. In FIG. 1, the optical sensors 12 are arranged, with respect to the longitudinal direction 4, in close vicinity to their respective print station 1, e.g. a small longitudinal distance before the print head of their respective print station 1. The optical sensors 12 record images of the surface areas 13 used to register raster lines of the single-color images printed by the individual print stations 1. To this end, they are connected to a printer controller 9 by data lines which transfer data representing recorded surface images. The controller 9 has a storage 15 arranged to store surface recordings obtained at the first print station 1 (i.e. the most upstream print station). The controller 9 is programmed such that it implements three comparators 10, 10′, 10″ for comparing a stored surface image of the first print station 1 with recorded surface images of the second, third and fourth print station 1, respectively. It is likewise possible to compare recordings of the first and second print station, the second and third print station, and the third and fourth print station, respectively. The controller 9 is also connected to the print head of each print station 1 and may be connected to the advance mechanism. It translates image data representing the image to be printed and received from outside into printing commands for each print station 1. It performs, using the registration information from the optical sensors 12 and the comparators 10, 10′, 10″, the translation such that the single-color images printed by the individual print stations 1 are registered onto each other. In other embodiments, the comparators are not implemented by the controller 9, but are distinct devices. In further embodiments, only one comparator 10 (implemented by the controller or separate) is provided which carries out all the three comparisons mentioned above. The optical sensors 12 also record images of the surface areas 13 used to provide print-station-individual clock signals indicative of the advance movement of the recording medium 6 at the respective print station 1 (the recordings used therefor may include the recordings used for the registration procedure). The generation of the movement clock signal is based on comparing subsequent recordings of one and the same optical sensor 12, i.e. on local comparisons. To this end, in FIG. 1 each optical sensor 12 is equipped with a local movement signal generator 11 which performs the local comparison of subsequent recordings and generates the print-station-individual movement clock signals. The movement clock signals define the longitudinal dot raster for the individual print stations 1. As will be explained in connection with FIG. 5, the movement clock signals of the second, third and fourth print stations 1 are repeatedly “re-synchronized” so as to re-register the dot rasters defined by them to the first print station's dot raster. FIG. 4 illustrates an embodiment of the optical sensor 12. The photosensor array 14 is here a two-dimensional array of photosensor elements, such as charge-coupled devices (CCDs), CMOS devices, or amorphous silicon devices. Optionally, one or more light sources 41 may be provided to illuminate the surface area 13 to enhance contrast of the surface structure (e.g. a paper fiber structure). Light from the light source 41 is collimated at illumination optics 42 and then redirected by an amplitude splitting beam-splitter 43 to illuminate the recording medium surface in the area 13. Reflected or scattered light from the surface area 13 is passed through the beam-splitter 43 for aperturing and filtering at element 44 and focusing by element 45 to an image on the photosensor array 14 which detects the focused light from the recording medium. The magnification of the imaging optics 45 is constant over the field-of-view of the photosensor array 14. Further optical elements such as lenses, spatial-frequency filters, color filters polarization filters, etc. may be used to improve the quality of the image on the photosensor array 14. The patterns or structures detected on the surface of the recording medium by the optical navigation sensor are inherent in the recording medium material, such as fibers in print paper. Therefore, no pre-printed marks, such as index marks, encoding marks or the like, are required on the recording medium 6 or the belt 2 (however, the registration and movement signal generation also works if a recording medium is used with pre-printed marks or any other structures printed on it). FIG. 5 illustrates an embodiment of the registration process for a first print station 1 and a second print station 1′ with print heads 51, 51′ and optical sensors 12, 12′. The recording medium 6 is moved in the advance direction 55. The first print station 1 is upstream of the second print station 1′. The optical sensors 12, 12′ are arranged a certain distance upstream of their respective print heads 51, 51′ so that information recorded by them can still influence subsequent printing at the recorded position, despite the recording medium movement. For the purpose of simplification, in FIG. 5 the sensors 12, 12′ are shown at the same longitudinal positions as the print heads 51, 51′, and it is assumed that the recording of surface images instantaneously influences the raster to be printed. The progress of the registration and print process is illustrated by seven “snap shots”, one below the other, of subsequent phases of the recording medium's advance movement. The squares 56, 58 shown in FIG. 5 do not indicate that squares are visible on the recording medium 6. Rather, they illustrate, in a virtual manner, images of surface areas 13 of the recording medium 6 which are recorded by the optical sensors 12, 12′ and compared to achieve registration. Likewise, the circles 57, 58 in FIG. 5 do not show actually printed ink dots, but they rather illustrate the longitudinal positions of virtual single-color raster lines (ink may or may not be printed on these lines, depending on the picture to be printed). At time t0, an image 56a of the recording medium surface at the current recording medium position is recorded by the first optical sensor 12 and the first print station's print head 51 prints the first raster line 57a of its single-color image. The recorded image data is then transferred to the controller 9 (FIG. 1) and stored in the storage 15 so that it is available for a later comparison with surface images recorded at the second print station 1′. Between time t0 and time t01, the first print station's print head 51 prints raster lines 57b, 57c, 57d of its single-color image. The relative longitudinal positions of the raster lines 57a to 57d and further raster lines to be printed are defined by movement clock signals which are, for example, derived from a local comparison of surface images constantly recorded by the first optical sensor 12. For example, each movement clock signal triggers the printing of one raster line 57. The raster lines 57 are triggered such that an image with a constant dot spacing R1 (e.g. R1=1199 dpi) close to a nominal dot spacing R (e.g. R=1200 dpi) is obtained. The deviation between R1 and R will generally be due to systematic errors. Every Nth clock signal (N=5 in FIG. 5) triggers the recording of a surface image 56. Consequently, at time t01, the movement clock signal following the predetermined number N of movement clock signals triggers recording of a second image 56b by the first optical sensor 12 of the medium surface at the current print medium position. This image 56b is also transferred and stored so that it is available for a later comparison with surface images recorded at the second print station 1′. These steps are repeated, as indicated at time t02 in FIG. 5. The storage 15 is preferably a FIFO stack (first-in-first-out stack), and the surface images 56a, 56b, 56c, etc. are preferably stored on the FIFO stack so that they can be used by the second print station 1′ to register its single-color image to the first print station's image in a first-in-first-out manner. The optical sensor 12′ at the second print station 1′ and the comparator 10 constantly record surface images of the recording medium and test them for correspondence with the first print station's first recording 57a. At time t1, the recording medium area which was recorded in the first station's first surface image 56a arrives at the second print station's optical sensor 12′, and the comparator detects that the second print station's currently recorded surface image 58a corresponds to the stored first station's first surface image 56a. This information is now used to register the first raster line 59a of the image printed by the second print station 1′ to the first raster line 57a of the first print station's image (the lateral displacement of the surface images 56, 58 and the dots 57, 59 in FIG. 5 is only shown to increase the legibility of the figure). The raster printed by the second print station 1′ is defined by a movement clock signal of the second print station 1′. The re-registration is, for example, achieved by synchronizing the second print station's movement clock signal such that the second print station's first raster line 59a is positioned at the first print station's first raster line 57a. The second print station's movement clock signals are derived from a local comparison of surface images constantly recorded by the second optical sensor 12′. Owing to the synchronization of the movement clock signal, raster lines 59b, 59c, 59d printed subsequently by the second station's print head 51′ follow the registered first raster line 59a with the required raster spacing. As can be seen in the representation of the time interval between t1 and t11, the raster lines 59 of the second print station 1′ cumulatively deviate from the first print station's raster lines 57. The cumulative error after five raster lines is denoted by 60 in FIG. 5. It is due to systematic errors which will generally cause the raster produced by the second station's movement clock signal to be slightly different from the one produced by the first station's movement clock signal. For example, the second print station's dot spacing may be R2=1201 dpi, i.e. close to the nominal dot spacing R, but not identically to R or R1. At time t11, the first print station's second surface image 56b arrives at the second print station's optical sensor 12′, and the comparator detects that the second print station's currently recorded surface image 58b corresponds to the surface image 56b. This information is now used to re-register the next raster line 59f of the image printed by the second print station 1′ to the corresponding raster line 57f of the first print station's image. Again, the re-registration is, for example, achieved by re-synchronizing the second print station's movement clock signal such that the raster line 59f is positioned at the corresponding first print station's raster line 57f. Owing to the re-synchronization of the movement clock signal subsequent raster lines printed by the second print head 51′ follow the re-registered raster line 59f with the required raster spacing. Since every N raster line a correspondence will be detected between a surface image 56 recorded at the first print station 1 and a surface image 58 recorded at the second print station 1′, this re-registration and re-synchronization procedure is repeated after N raster lines, so that an error accumulation beyond the one illustrated in FIG. 5 is avoided. FIG. 6 illustrates the recording and comparing of exemplary surface images 56a, 58a recorded by the optical sensors 12, 12′ at t0 and t1 in FIG. 5. The surface recordings 56a and 58a are shown in a rasterized form, as typically obtained with a two dimensional CCD sensor array 14 (FIG. 4). The surface image 56a includes an image 61 of an exemplary surface structure element of the recording medium, for example a paper fiber. An identical or similar image 61′ of the same paper fiber is included in the second print station's surface recording 58a. Using conventional image processing methods, the comparator 10 (FIG. 1) detects that the surface images 56a and 58a correspond to each other and provides a corresponding registration signal which is used in the registration procedure, as described in connection with FIG. 5. For example, the surface images 56a, 58a each may be mathematically represented by a two-dimensional matrix, the dimensions of which correspond to the pixel numbers in the longitudinal and transversal directions of the recordings 56a, 58a (which, in turn, may correspond to the dimensions of the photosensor arrays 14 (FIG. 4)). The matrix elements may represent the gray-level measured in each pixel of the photosensor array. A correspondence may be found by comparing the two matrices, for example by an estimator function (e.g. a least-squares-estimator) which quantifies the degree of deviation between the two surface recordings 56a, 58a compared. If the quantified deviation is smaller than a certain maximum deviation, a “correspondence” between the two surface recordings 56a and 58a is detected; and the registration procedure is based on this detection of the correspondence, as described above. The same procedure is carried out for subsequent recordings 56b, 58b; 56c, 58c; etc. In some of the embodiments, the images of the surface structures 61, 61′ may be relatively shifted within the images 56a, 58a; 56b, 58b; 56c, 58c; etc., and the amount of shift is then also determined (similar to the explanation of FIG. 7 below). The shift determined is then taken into account in the registration of the second print station's raster lines 59a; 59b; 59c; etc. to the corresponding first print station's raster lines 57a; 57b; 57c; etc. FIG. 7 illustrates a local comparison of surface images to measure the movement of the recording medium, an information on which the movement clock signal generation is based. A surface image 56x is recorded at the first print station 1 at a time tx. It includes an image 61 of a surface structure, e.g. a paper fiber (similar to FIG. 6) at a certain position in the image 56x. A short time interval later, at time ty, another surface image 56y is recorded by the same print station's optical sensor 12. The time interval between tx and ty is, for example, a fraction of the time needed to advance the recording medium from one raster line (e.g. 57a) to the next one (e.g. so as to provide movement information with a resolution better that the dot spacing). In the second recording 56y, the position of the image 61′ of the structure element is shifted by a distance d with respect to its position in the first surface image 56x. The distance d corresponds to the advance of the recording medium in the time interval between tx and ty. The shift d is, for example, determined by using mathematical matrix representations of the surface recordings 56x and 56y, similar to FIG. 6 described above. In one of the matrices (e.g. the one corresponding to 56y), the represented image is mathematically shifted in a stepwise manner (matrix elements which are artificially entered in such a mathematical-shift operation are set to a neutral value, e.g. to 0). Comparisons between the other (unshifted) matrix (e.g. 56x) and each of the shifted matrices are then carried out, and the degree of deviation is determined for each shifted matrix (similar to FIG. 6 described above). One of the shifted matrices will provide a minimum degree of deviation from the unshifted matrix. The amount by which this matrix was shifted is an estimate of the actual shift d between the surface structures, and, accordingly, of the movement of the recording medium in the time interval from tx to ty. By repeatedly carrying out this local recording and comparison procedure, the recording-medium advance is measured. The generation of the movement clock signal is based on this measurement. The recording of the surface images 56x, 56y used for the local comparison is triggered by a clock which is independent of the recording-medium movement. If, for example, at a typical recording-medium speed four such recordings are triggered between two subsequent raster lines 57, the sum of the distances d determined in four such recordings will approximately correspond to a dot distance, so that a movement clock signal will be generated after the fourth recording. In the embodiment shown in FIG. 1, such a local recording and comparison of surface images is carried out at each of the print stations 1 so that the print operation of each print station 1 is individually triggered by print-station-individual movement clock signals, as illustrated in FIG. 5. In other embodiments, such a local image recording and comparison procedure is only carried out at one of the print stations 1, preferably the first print station, and the movement clock signals derived from it are used as common movement clock signals by all print stations. FIG. 8 illustrates two other embodiments of a printer in which the movement signal generation is based on encoder signals. Apart from that, the printer shown in FIG. 8 corresponds to the one of FIG. 1. In one of the embodiments, one of the rollers 3 is equipped with a rotary encoder 81 with encoder marks 82 and an encoder mark sensor 83. The encoder marks 82 are arranged near the circumference of the face of the roller 3 and rotate together with the roller 3. The encoding mark sensor 83 (for example, an optical sensor) is fixed and provides an encoder clock signal each time one of the encoder marks 82 passes by. The encoder clock signals are indicative of the advance movement of the belt 2 and the recording medium 6 disposed on the belt 2. They are used as a common movement clock signal for all print stations 1. Another embodiment of an encoder 84 is also illustrated in FIG. 8. It includes encoder marks 85 attached to the outer surface of the conveyor belt 2 near the belt edge, and encoder mark sensors 86 responsive to the encoder marks 85. Each print station 1 is equipped with its own encoder mark sensor 86. Each of the encoder mark sensors 86 provide an encoder clock signal when an encoder mark 85 passes by. The encoder mark sensors 86 are attached to their respective print stations 1 in a fixed mechanical relationship. The encoder clock signals are print-station-individual movement signals which are used for a print-station-individual definition of the raster lines of the different print stations 1, as explained in connection with FIG. 5. Thus, the described embodiments enable multicolor images to be printed with improved accuracy. All publications and existing systems mentioned in this specification are herein incorporated by reference. Although certain methods and products constructed in accordance with the teachings of the invention have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the invention fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Multicolor printers produce images which are composed of a plurality of different single-color images. The quality of the final multicolor image depends, i.a., on the registration accuracy of the single-color images. With the increasing resolution of modern printers the registration accuracy has become an issue of interest. Different multicolor printer types are known. Ink-jet printers have at least one print head from which droplets of ink are directed towards a print medium. Within the print head the ink is contained in a plurality of channels. Pulses cause the droplets of ink to be expelled as required from orifices or nozzles at the end of the channels. These pulses are generated e.g. by thermal components in thermal ink-jet print heads or by piezo-electric elements in drop-on-demand print heads. Ink-jet printers of the carriage type have a print head for each color. The print heads are mounted on a reciprocating carriage. Full-width or page-width ink-jet printers have, for each color, an array of nozzles extending across the full width of the print medium which is moved past the nozzle arrays. Each nozzle array is part of a print station which forms one single-color image or a part of it. Each print station produces its own single-color image on the print medium as it moves past the print stations. Each single-color image is composed of a plurality of closely spaced image dots, wherein single-color dots are superimposed to form a dot of a required color. The superimposed single-color dots may be printed onto each other or in a side-by-side relation. The recording medium may be paper or any other suitable substrate to which the ink adheres. In known color xerographic systems, instead of the nozzle arrays, a plurality of print bars are provided which produce an electrostatic charge image on a recording medium. The print bars are selectively energized to create successive charge images, one for each color. The print bars may, for example, be LED print bars which produce the charge image an a previously charged photoreceptive surface. Each LED print bar is associated with a development system, which develops a latent image of the last charge image or exposure without disturbing previously developed images. The fully developed color image is then transferred to an output sheet, e.g. paper or the like. It is also possible to form electrostatic charge images directly on the output sheet which is then exposed to a toner of the respective color to produce a visible image. To register single-color images for forming a multicolor image, encoder arrangements are utilized which determine the advance of the recording medium during the print process. Optical encoder systems are known in which an optical sensor is responsive to encoder marks. In page-width printers the recording medium is, for example, moved by a conveying belt which is driven by rollers or pulleys. The movement of the belt with the recording medium may be detected by a single rotary encoder which is mounted on one of the rollers or pulleys. The advance of the belt is controlled by advance information represented by the rotary encoder signals. It is also known to place the encoder marks on the belt. U.S. Pat. No. 5,526,107 is directed to a system and method for duplex printing wherein two images are registered at corresponding locations on the two sides of a print medium. The positions of the printed images relative to each other are synchronized by mechanical means or by detecting the position of special marks or an area of the image itself. It is mentioned that color-to-color registration may be achieved using a similar synchronization technique. U.S. Pat. No. 4,804,979 discloses an electrostatic color printer with several print stations. Encoding marks are printed on the recording medium (which is paper). Each print station has its own optical sensor responsive to the encoding marks to detect and correct for variations of the recording medium to obtain registration of the single-color images. The registration is checked every 50 raster lines and brought into exact registration, if necessary. EP 0 729 846 B1 discloses a high-speed ink-jet printing press in which registration marks are printed on the print medium. The registration marks are used, at low speeds, for aligning the recording stations, and, at high speeds, for registering the single-color images.
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<SOH> SUMMARY OF THE INVENTION <EOH>A first aspect of the invention is directed to a multicolor-printer. It comprises at least a first and a second print station, first and second optical sensors and a surface recordings comparator. The first and second print stations are arranged to print images on a surface of a moving print medium. The first and second optical sensors view, at the first and second print stations, an area of the print medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively. A storage is arranged to store the first surface recording. The surface recordings comparator is arranged to test, during the print medium movement, for correspondence of second surface recordings with the stored first surface recording. The printer is arranged to repeatedly, within one image, re-register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings. According to another aspect, a multicolor-printer is provided which comprises at least a first and a second print station, first and second optical sensors, a surface recordings comparator and at least one movement signal generator. The first and second print stations are arranged to print images on a surface of a moving print medium. The first and second optical sensors view, at the first and second print stations, an area of the print medium surface to obtain at least one first surface recording, in a manner related to the first print station's image printing, and second surface recordings, respectively. A storage is arranged to store the first surface recording. The surface recordings comparator is arranged to test, during the print medium movement, for correspondence of second surface recordings with the stored first surface recording. The movement signal generator generates signals representing recording medium movement. The printer is arranged to repeatedly, within one image, re-register raster lines of the image of the second print station to corresponding raster lines of the image of the first print station in response to correspondences found between the first and second surface recordings. Between repeated re-registrations, the first and second print stations are arranged to form their images by image dots on raster lines defined on the basis of the movement signals. According to another aspect, a method is provided of printing images onto each other on a surface of a moving print medium using a printer having at least a first and a second print station and first and second optical sensors viewing, at the first and second print stations, an area of the print medium surface. The method comprises recording a first surface recording at the first print station and relating it to a raster line of the image printed by the first print station; recording second surface recordings at the second print station and during the print medium movement, and testing for correspondence of the second surface recordings with the first surface recording; registering, in response to a correspondence found between one of the second surface recordings a corresponding raster line of the image printed by the second print station to the raster line of the image printed by the first print station. The activities of taking a first surface recording, taking second surface recordings, testing for correspondence, and registering a corresponding raster line of the image are repeated so that, within one image, repeated re-registrations are performed. According to another aspect, a method is provided of printing images onto each other on a surface of a moving print medium using a printer having at least a first and a second print station and first and second optical sensors viewing, at the first and second print stations, an area of the print medium surface. The method comprises recording a first surface recording at the first print station and relating it to a raster line of the image printed by the first print station; recording second surface recordings at the second print station and during the print medium movement, and testing for correspondence of the second surface recordings with the first surface recording; registering, in response to a correspondence found between one of the second surface recordings a corresponding raster line of the image printed by the second print station to the raster line of the image printed by the first print station. The activities of taking a first surface recording, taking second surface recordings, testing for correspondence, and registering a corresponding raster line of the image are repeated so that, within one image, repeated re-registrations are performed. Between repeated re-registrations, the images are formed by image dots on raster lines defined on the basis of the movement signals. Other features are inherent in the disclosed products and methods or will become apparent to those skilled in the art from the following detailed description of embodiments and its accompanying drawings.
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20040702
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20070515
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20050825
|
76004.0
| 0
|
NGUYEN, LAMSON D
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MULTICOLOR-PRINTER AND METHOD OF PRINTING IMAGES
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
|
|||
10,882,410
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ACCEPTED
|
Handling device for a replaceable consumable of a printhead service station of a printing device
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Disclosed is a handling device which comprises a lid, which may be arranged to cover at least partially a surface of a replaceable consumable of a printhead service station, engagement members for engaging the lid to the consumable, and a hand grip. The consumable may be replaced by engaging the handling device with the consumable while the latter is still in the service station, and removing the consumable from the service station with the handling device. The risk of getting ink on the user's hands when replacing a consumable is reduced.
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1. A handling device for a replaceable consumable of a printhead service station of a printing device, said handling device comprising: a lid member, intended to cover at least partially a surface of a consumable to be replaced; engagement means for engaging said lid member to said consumable; and gripping means. 2. A handling device as claimed in claim 1, wherein said engagement means are releasable. 3. A handling device as claimed in claim 1, wherein said engagement means comprise snap elements. 4. A handling device as claimed in claim 1, further comprising means to release the consumable to be replaced from the service station. 5. A handling device as claimed in claim 1, wherein said lid member is such as to cover substantially all the surface of said consumable that is exposed to ink drops or to ink aerosol during a servicing operation when the consumable is in the service station. 6. A handling device as claimed in claim 1, comprising a sealing member between the lid member and the consumable. 7. A handling device as claimed in claim 1, wherein said device is associated to a replacement part for said consumable. 8. A handling device as claimed in claim 1, wherein said handling device is disposable. 9. A handling device for replacing a consumable of a printhead service station of a printing device, said handling device comprising: a lid, shaped to cover at least partially a surface of a consumable to be replaced; at least one engagement member for engaging said lid to said consumable; and a hand grip for gripping said lid. 10. Replacement assembly for replacing a consumable of a printhead service station of a printing device, comprising a replacement part for said consumable and a handling device, said handling device comprising: a lid member, intended to cover at least partially a surface of a consumable to be replaced; engagement means for engaging said lid member to said consumable; and gripping means. 11. A consumable for a printhead service station of a printing device, wherein said consumable comprises means for engagement to a handling device, said handling device comprising: a lid member, intended to cover at least partially a surface of a consumable to be replaced; engagement means for engaging said lid member to said consumable; and gripping means. 12. A consumable as claimed in claim 11, said consumable being at least one of a capping module, a spittoon module or a wiping module. 13. A printhead service station for a printing device, said service station being provided with at least one consumable which comprises means for engagement to a handling device, said handling device comprising: a lid member, intended to cover at least partially a surface of a consumable to be replaced; engagement means for engaging said lid member to said consumable; and gripping means. 14. A printhead service station as claimed in claim 13, wherein said consumable is at least one of a capping module, a wiping module and a spittoon module. 15. A printhead service station as claimed in claim 14, wherein each of said modules is an integral member that serves all the printheads. 16. A method for replacing a replaceable consumable of a printhead service station of a printing device, said method comprising the steps of: providing a handling device for said replaceable consumable, said handling device comprising a lid member, intended to cover at least partially a surface of the consumable to be replaced, engagement means for engaging said lid member to said consumable, and gripping means; engaging said handling device with said consumable while the latter is still in said service station; and removing said consumable from the service station by means of said handling device. 17. A method as claimed in claim 16, further comprising releasing the consumable from the service station during the engagement of the handling device with the consumable. 18. A method as claimed in claim 16, wherein said handling device is provided together with a replacement part of said consumable. 19. A method as claimed in claim 18, wherein said handling device is provided engaged to said replacement part, the method further comprising the step of releasing the handling device from the replacement part before engaging it with the consumable in the service station. 20. A method as claimed in claim 18, further comprising the step of disposing of said handling device together with the consumable to be replaced.
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The present invention relates to a handling device for a replaceable consumable of a printhead service station of a printing device. An inkjet printing apparatus comprises one or more printheads, which perform printing by ejecting drops of ink on a printing media through a plurality of nozzles. In order to avoid build up of dirt, dry ink or other sources of obstruction in the printhead nozzles, and to maintain an optimum printing quality, the apparatus is typically provided with a service station to perform cleaning and maintenance operations on the printheads. The service station is arranged within the printing apparatus, either stationary or on a movable carriage, and usually includes a capping module for covering the printheads when the printer is not is use, a wiping module comprising elastomeric wipers for wiping the printheads, and a spittoon module. A spittoon is a reservoir for waste ink, into which the printheads eject or fire a number of drops of ink in a servicing operation known as “spitting”, with the aim of clearing the nozzles of the printhead from clogs and prevent their obstruction. Typically, the printheads can be moved over the service station for maintenance. The modules of the service station that have been described may be consumable elements, especially in the case of large format printers, and they need to be replaced by the user with a certain frequency; for this purpose the user has to remove the old consumable from the apparatus and put a new one in its place. When the service station is mounted on a carriage, the carriage is moved towards a maintenance position to allow the user to perform the replacement more easily. However, when the user replaces a consumable of the service station there is a risk that he gets soiled with ink when gripping and handling the consumable elements that need to be replaced; this is due to the fact that the surfaces of the consumables of the service station usually become dirty with ink during the printhead servicing operations. Most of the ink on the service station surfaces is caused by the spitting operation: not only because of the ink drops actually fired by the printhead, but especially due to the fact that during spitting a cloud or aerosol of ink arises all around the printhead and thus over the service station, and eventually deposits on the exposed surfaces. Another source of such dirt is the ink that is projected from the elastomeric wipers during wiping of the printhead nozzles. Over time, the soiling of the consumables can become quite important, especially if the apparatus and the service station are designed such that replacement of the consumables is not required often. The aerosol may soil not only the spittoon module, but also other parts of the service station and other consumables that are located nearby. Some printing apparatus have for each printhead a single cleaning element that includes the capping, wiping and spittoon modules, such that the user replaces the whole cleaning element when needed. Such a structure is described for example in U.S. Pat. No. 6,402,290, assigned to the present applicant; in this document, the cleaning elements are provided with a handle at the front portion thereof, away from the spittoon module, that is located in its turn at the back of the cleaning element (as viewed from the front of the printing apparatus). Thus, the handle can be kept relatively clean and there is a relatively small risk that the user gets ink on his hands when replacing the consumable. However, in some printers each module of the service station is a separate consumable element and needs to be replaced separately from the others, because each consumable has a different life: caps depend on aerosol dirtiness, wiper on ink accumulation and spittoon on the available capacity. In this case more handles would be needed, at least some of which cannot be protected from the ink aerosol. Another factor/that increases the possibility that the user gets ink on his hands when replacing the consumables is the desirable tendency of dimensioning and structuring service stations such as to allow consumables to be replaced only rarely, e.g. once a year: in this case, the amount of ink that may build up on the surfaces of the consumables may be quite large. In the case of the spittoon, apart from the ink that is deposited on the surfaces, there is a further problem in that the module to be replaced may contain liquid ink that can spill if the user tilts the module. The present invention seeks to improve the operation of replacement of a consumable element of a printhead service station by a user, and reduce the risk of ink stains. According to one aspect of the present invention, a handling device for a replaceable consumable of a printhead service station of a printing device comprises: a lid member, intended to cover at least partially surface of a consumable to be replaced; engagement means for engaging said lid member to said consumable; and gripping means. Such a handling device allows a user to remove a consumable from the service station without the need of touching any of its surfaces, and thus without the risk of getting ink on his hands. The removal is performed safely and easily by virtue of the gripping means. Said engagement means may be releasable; this allows the handling device to be disengaged from the consumable, if desired, e.g. in order to recycle the parts., and it also allows to provide a handling device coupled to every replacement part for the disposable. The engagement means may comprise snap elements; this feature makes the engagement very fast and simple. The device may further comprise means to release the consumable to be replaced from the service station. This feature avoids the need to provide an independent system for the release of the consumable prior to its handling with the handling device. In some embodiments, said lid member is such as to cover substantially all the surface of said consumable that is exposed to ink drops or to ink aerosol during a servicing operation when the consumable is in the service station. Thus, there is no risk that the user gets ink on his hands, clothes, etc. by touching accidentally a dirty surface. In some cases the handling device may comprise a sealing member between the lid member and the consumable. This reduces the possibility of ink spills from the consumable, and it is particularly useful when the handling device is associated to a spittoon module. In some embodiments of the invention, said handling device is associated to a replacement part for said consumable. In this case the handling device is always at hand and ready when a consumable has to be replaced. The handling device may be disposable. This has the advantage that the user, after removal of the consumable from the service station, does not need to perform any further operation on the device and the consumable attached to it, and just disposes of the assembly suitably. According to a second aspect, the present invention relates to a handling device for replacing a consumable of a printhead service station of a printing device, said handling device comprising: a lid, shaped to cover at least partially a surface of a consumable to be replaced; at least one engagement member for engaging said lid to said consumable; and a hand grip for gripping said lid. According to a further aspect, the present invention relates to a replacement assembly for replacing; a consumable of a printhead service station of a printing device, comprising a replacement part for said consumable and a handling device, said handling device comprising: a lid member, intended to cover at least partially a surface of a consumable to be replaced; engagement means for engaging said lid member to said consumable; and gripping means. According to another aspect, the invention relates to a consumable for a printhead service station of a printing device, wherein said consumable comprises means for engagement to a handling device as described. Said consumable may be at least one of a capping module, a spittoon module or a wiping module. In another aspect, the invention relates to a printhead service station for a printing device, said service station being provided with at least one consumable as described. In embodiments of the invention, said consumable is at least one of a capping module, a wiping module and a spittoon module; each of said modules may be an integral member that serves all the printheads. In a further aspect, the present invention provides a method for replacing a replaceable consumable of a printhead service station of a printing device, said method comprising the steps of: providing a handling device for said replaceable consumable, said handling device comprising a lid member, intended to cover at least partially a surface of the consumable to be replaced, engagement means for engaging said lid member to said consumable, and gripping means; engaging said handling device with said consumable while the latter is still in said service station; and removing said consumable from the service station by means of said handling device. The method may further comprise releasing the consumable from the service station during the engagement of the handling device with the consumable. In some embodiments, said handling device is provided together with a replacement part of said consumable. In this case, the handling device may be provided engaged to said replacement part, and the method may further comprise the step of releasing the handling device from the replacement part before engaging it with the consumable in the service station. The method may also comprise the step of disposing of said handling device together with the consumable to be replaced. Particular embodiments of the present invention will be described in the following, only by way of non-limiting example, with reference to the appended drawings, in which: FIG. 1 shows a perspective view of an ink-jet printing apparatus having a printhead service station; FIG. 2 shows a perspective view of a service station having separate modules for each cleaning function; FIG. 3 shows in perspective one embodiment of a handling device according to the present invention: and FIGS. 4a to 4d show four steps of an embodiment of a method that uses a handling device according to the present invention for replacing a consumable of a service station. FIG. 1 illustrates an embodiment of an ink-jet printing apparatus that comprises a housing 1 mounted on a stand 2, means (not shown) for advancing a media M to be printed through the apparatus, and a reciprocating printhead carriage 3 on which inkjet printheads 4 are arranged. The printhead carriage 3 reciprocates on a guide rod 31 along a scan axis X for printing on the underlying media M. At one end of the housing 1 is arranged a printhead service station 5, in a position such as to allow the printhead carriage 3 to be moved over the station for performing maintenance operations on the printheads 4. FIG. 2 shows in more detail an embodiment of a service station with consumable elements, where the handling device according to the present invention can be applied. In FIG. 2 the service station 5 comprises an enclosure 50 in which are arranged: a capping module 51, which has the purpose of covering the printheads when the apparatus is not in use, so that they are protected from dust and the ink is prevented from drying; a wiping module 52, comprising a plurality of moveable elastomeric wipers whose function is to wipe the nozzles of the printheads to remove ink residue, dust and debris; and a spitting module or spittoon module 53, which consists essentially in a waste ink reservoir into which the printheads fire a number of droplets of ink with the purpose of clearing the nozzles from clogs, dirt, dried ink and the like. The spittoon module 53 may comprise a foam absorber or other means for avoiding ink spills, as described in the earlier patent applications that have been mentioned above. In this example each of the modules 51,52 and 53 is an integral member that serves all the printheads, although this may be different in other service station embodiments. Here, each module comprises a number of appropriate service elements, one for each printhead; FIG. 2 shows an example of a service station for six printheads. The service station 5 is mounted on a service station carriage 54 displaceable in a direction Y, at right angles to the scan axis X, for selectively placing each of the modules in a suitable position under the printheads, in order to perform the corresponding servicing operation. The three modules are releasably attached to the carriage 54, for example by means of toothed projections that engage a rim at the bottom of the consumable (not shown in this figure and only schematically in FIGS. 4b to 4d, where the toothed projections are indicated with reference 55). As shown in FIG. 2, the capping module 51 is located at the rear side of the carriage 54 as seen from the front of the apparatus, the spittoon module 53 is in the centre of the carriage and the wiping module 52 is located at the front side of the carriage, thus being more easily accessible to the user. As described above, in this case the service station modules are consumable elements that need to be replaced over time; as explained before, in the embodiment shown in FIG. 2 each module 51,52 and 53 is an integral ember and is independent from the others, and each of them may be replaced when appropriate. During the spitting and wiping operations the whole of the service station, and especially the spittoon module 53, become dirty due to the ink aerosol and ink drops ejected from the printheads or caused by the wipers. Also the capping module becomes quite dirty because it is very close to the spittoon; and the capping module reliability depends on the sealing capability, which can be damaged by the aerosol and dust. All the surfaces that remain exposed during the cleaning operations, i.e. at least the upper surfaces of the capping, spitting and wiping modules, will receive ink drops and aerosol and will become dirty. In the context of the present specification and claims, by exposed surface it is meant a surface that is exposed to ink drops and aerosol during any of the servicing operations performed on a printhead in the service station. For the purpose of preventing a user from getting dirty, i.e. getting ink on his hands, during the replacement of any of the consumables, in one embodiment the present invention provides a handling device 6 as shown in FIG. 3. The handling device 6 comprises, in the example shown in enlarged view in FIG. 3, a lid portion 61 which is dimensioned such as to cover substantially all the exposed surface of the consumable; in this example the handling device 6 will be described applied to the spittoon module 53. It will be understood that an equivalent handling device may be applied to the other modules. It is also possible to design a lid that may be used for all three consumables, since their size is very similar. At the periphery of the lid portion 61 there are snap engagement elements 62 (only those at one side being visible in the figure) which cooperate with complementary engagement elements (not shown) provided on the consumable 53. As shown in the figure, the engagement elements 62 may be resilient tabs provided with a tooth, such that the tooth is engaged in complementary openings in the side wall of the disposable element. However, it has to be noted that any other suitable engagement system can be used. The engagement between the handling device 6 and the consumable 53 is releasable by the user. In FIG. 3, the tabs are shown with a projecting tongue at their lower end: the user may pull the tongues outwards for releasing the tooth from the opening in the side wall of the disposable element. The device 6 also comprises two elongate tabs 63 for releasing the corresponding module from the carriage 54: when the lid portion is placed on the consumable 53, the tabs 63 unclip the toothed projections from the rim at the bottom of the consumable, thus releasing the latter from the carriage 54. It has to be noted that the means of engagement of the consumable to the carrier, and therefore the means provided on the handling device to release said engagement, may be of any other kind. The handling device 6 may also be provided with a suitable seal (not shown) at the periphery of the lid portion 61, in order to avoid any spill of liquid from the spittoon module 53 when it is being replaced. On the outer and upper side of the lid portion is formed a gripping handle 64, such that the device may be easily and safely held by the user. In the following a method according to an embodiment of the invention, for replacing a replaceable consumable of a printhead service station of a printing device, will be described with reference to FIGS. 4a to 4d. According to this method, a handling device 6 is provided together with a replacement part, for example a replacement part 53R for a spittoon module. The user removes the replacement part 53R together with the handling device 6 from the corresponding package P (FIG. 4a). FIG. 4b shows very schematically a side view of the service station carriage 54 with the capping module 51 and wiping module 52, the spittoon module 53 that needs to be replaced, and the toothed tongues 55 that engage a rim at the bottom of each consumable in order to maintain it engaged to the carriage 54. Once removed the replacement part 53R from the package, the user releases the handling device 6 from the replacement part, which is new and therefore clean from ink and can be handled safely, and applies it onto the spittoon module 53 that needs to be replaced (FIG. 4c), and that is soiled with ink. The device engages the module 53 by virtue of the engagement means 62, and at the same time releases the consumable from the service station carriage 54 by means of the tabs 63 that press the toothed tongues 55 out of engagement with the rim of the consumable. The user can then remove the module from the service station carriage 54, by gripping and pulling up the handling device 6 and the module 53 attached to it with no risk of getting ink on his hands, since the exposed surfaces of the module 53 remain covered by the lid portion 61 of the device 6, and the user does not need to touch the module at all. Then the user places by hand the new and clean replacement part 53R in position in the carriage 54, as shown in FIG. 4d, and may dispose of the old spittoon module as necessary. The user can dispose of the handling device 6 together with the consumable 53, such that, on one hand, he does not need to disengage them, and, on the other hand, the module is kept safely sealed and provided with handling means at all times while under the user's control. Although the present specification describes embodiments of the invention by way of example, it has to be noted that many variants are possible. For instance, the handling device does not need to be disposable, and is not necessarily associated to a replacement part; and, when supplied together with the replacement, it may be engaged to the replacement or separate from it. In the latter case, the engagement means don't need to be releasable by the user. The gripping means may be of any other type and shape suitable for the purpose.
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20040702
|
20070501
|
20050210
|
72244.0
| 0
|
VO, ANH T N
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HANDLING DEVICE FOR A REPLACEABLE CONSUMABLE OF A PRINTHEAD SERVICE STATION OF A PRINTING DEVICE
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UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||||
10,882,563
|
ACCEPTED
|
Transistor structures and transistors with a germanium-containing channel
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A transistor structure includes a first undoped, silicon-containing channel layer, a buried germanium channel, and a second undoped, silicon-containing channel layer. The first and second channel layers may contain SiGe or, alternatively, Si only. Another transistor structure includes a first channel layer, a buried germanium channel, and a second, undoped channel layer containing silicon and germanium over the buried channel. A further transistor structure includes a first channel layer, a buried germanium channel, and a second channel layer containing compositionally graded SiGe over the buried channel. A still further transistor structure includes a first silicon layer, an undoped or homogeneously doped buried channel containing silicon and germanium, and a second silicon layer over the buried channel.
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1. A transistor structure comprising: a first undoped, silicon-comprising channel layer over a substrate; a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer; and a second undoped, silicon-comprising channel layer over the buried channel. 2. The structure of claim 1 wherein the buried channel exhibits a charge carrier mobility greater than that of both the first and second channel layers. 3. The structure of claim 1 wherein the buried channel consists of germanium. 4. The structure of claim 1 wherein the buried channel is on and in contact with the first channel layer. 5. The structure of claim 1 wherein the second channel layer is on and in contact with the buried channel. 6. The structure of claim 1 wherein at least the second of the channel layers consists of silicon and germanium. 7. The structure of claim 1 wherein the first and second channel layers consist of silicon. 8. The structure of claim 1 wherein at least one of the first and second channel layers consists of compositionally graded SiGe having a higher Ge content at an interface with the buried channel in comparison to other portions of the at least one first and second channel layers. 9. The structure of claim 1 wherein the first and second channel layers have thicknesses of from about 100 Å to about 600 Å. 10. The structure of claim 1 wherein the buried channel has a thickness of from about 300 Å to about 600 Å. 11. The structure of claim 1 wherein the substrate comprises a SOI substrate. 12. The structure of claim 1 wherein the substrate comprises a bulk silicon wafer. 13. The structure of claim 1 further comprising a gate dielectric layer having a K greater than 3.9 over the second channel layer. 14. The structure of claim 13 wherein a distance from a gate dielectric layer/second channel layer interface to the germanium buried channel is from about 50 to about 100 Angstroms. 15. The structure of claim 1 further comprising: a gate over the second channel layer; and a source and a drain in electrical connection with the buried channel. 16. The structure of claim 1 comprised by a memory device. 17. A transistor structure comprising: a first channel layer over a substrate; a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer and exhibiting a charge carrier mobility greater than that of the first channel layer; and a second, undoped channel layer consisting of silicon and germanium over the buried channel. 18. The structure of claim 17 wherein the buried channel consists of germanium. 19. The structure of claim 17 wherein the buried channel is on and in contact with the first channel layer. 20. The structure of claim 17 wherein the second channel layer is on and in contact with the buried channel. 21. The structure of claim 17 wherein the first channel layer consists of silicon, germanium, and, optionally, a dopant. 22. The structure of claim 17 comprised by a memory device. 23. A transistor structure comprising: a first channel layer over a substrate; a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer and exhibiting a charge carrier mobility greater than that of the first channel layer; and a second channel layer consisting of compositionally graded SiGe and, optionally, a dopant, the second channel layer being over the buried channel. 24. The structure of claim 23 wherein the second channel layer has a higher Ge content at an interface with the buried channel in comparison to other portions of the second channel layer. 25. The structure of claim 23 wherein the buried channel consists of germanium. 26. The structure of claim 23 wherein the buried channel is on and in contact with the first channel layer. 27. The structure of claim 23 wherein the second channel layer is on and in contact with the buried channel. 28. The structure of claim 23 wherein the first and second channel layers are undoped. 29. The structure of claim 23 wherein the first channel layer consists of silicon, germanium, and, optionally, a dopant. 30. The structure of claim 23 wherein the first and second channel layers have thicknesses of from about 100 Å to about 600 Å. 31. The structure of claim 23 wherein the buried channel has a thickness of from about 300 Å to about 600 Å. 32. The structure of claim 23 comprised by a memory device. 33. A transistor comprising: a first channel layer consisting of compositionally graded SiGe and, optionally, a dopant, the first channel layer being over a substrate; a buried channel consisting of germanium on and in contact with the first channel layer; a second channel layer consisting of compositionally graded SiGe and, optionally, a dopant, the second channel layer being on and in contact with the buried channel, the first and second channel layers having a higher Ge content at an interface with the buried channel in comparison to other portions of the first and second channel layers, and the buried channel exhibiting a charge carrier mobility greater than that of both the first and second channel layers; a gate dielectric layer having a K greater than 3.9 over the second channel layer; a gate over the gate dielectric layer; and a source and a drain in electrical connection with the buried channel. 34. The transistor of claim 33 wherein a distance from a gate dielectric layer/second channel layer interface to the germanium buried channel is from about 50 to about 100 Angstroms. 35. The transistor of claim 33 wherein the substrate comprises a SOI substrate. 36. The transistor of claim 33 wherein the substrate comprises a bulk silicon wafer. 37. The transistor of claim 33 comprised by a memory device. 38. The transistor of claim 37 wherein the memory device is DRAM. 39. The transistor of claim 37 wherein the memory device is further comprised by a computer system that includes a microprocessor. 40. A transistor structure comprising: a first silicon layer over a substrate; an undoped or homogeneously doped buried channel comprising silicon and germanium over the first channel layer; and a second silicon layer over the buried channel. 41. The structure of claim 40 wherein the buried channel exhibits a charge carrier mobility greater than that of both the first and second channel layers. 42. The structure of claim 40 wherein the buried channel is undoped and consists of silicon and germanium. 43. The structure of claim 40 wherein the buried channel is on and in contact with the first channel layer. 44. The structure of claim 40 wherein the second channel layer is on and in contact with the buried channel. 45. The structure of claim 40 wherein the first and second channel layers consist of silicon. 46. The structure of claim 40 wherein the first and second channel layers have thicknesses of from about 100 Å to about 600 Å. 47. The structure of claim 40 wherein the buried channel has a thickness of from about 300 Å to about 600 Å. 48. The structure of claim 40 wherein the substrate comprises a SOI substrate. 49. The structure of claim 40 wherein the substrate comprises a bulk silicon wafer. 50. The structure of claim 40 further comprising a gate dielectric layer having a K greater than 3.9 over the second channel layer. 51. The structure of claim 50 wherein a distance from a gate dielectric layer/second channel layer interface to the germanium buried channel is from about 50 to about 100 Angstroms. 52. The structure of claim 40 further comprising: a gate over the second channel layer; and a source and a drain in electrical connection with the buried channel. 53. The structure of claim 40 comprised by a memory device. 54. A transistor comprising: a first channel layer consisting of silicon and, optionally, a dopant, the first channel layer being over a substrate; an undoped or homogeneously doped buried channel otherwise consisting of silicon and germanium on and in contact with the first channel layer; and a second channel layer consisting of silicon and, optionally, a dopant, the second channel layer being on and in contact with the buried channel and the buried channel exhibiting a charge carrier mobility greater than that of both the first and second channel layers; a gate dielectric layer having a K greater than 3.9 over the second channel layer; a gate over the gate dielectric layer; and a source and a drain in electrical connection with the buried channel. 55. The transistor of claim 54 wherein the first and second channel layers consist of silicon and a dopant. 56. The transistor of claim 54 wherein a distance from a gate dielectric layer/second channel layer interface to the germanium buried channel is from about 50 to about 100 Angstroms. 57. The transistor of claim 54 wherein the substrate comprises a SOI substrate. 58. The transistor of claim 54 wherein the substrate comprises a bulk silicon wafer. 59. The transistor of claim 54 comprised by a memory device. 60. The transistor of claim 59 wherein the memory device is DRAM. 61. The transistor of claim 59 wherein the memory device is further comprised by a computer system that includes a microprocessor.
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TECHNICAL FIELD The inventions pertain to transistor structures and transistors that include a channel containing germanium. The channel may be buried. BACKGROUND OF THE INVENTION Operation of semiconductor devices typically depends upon movement of charge carriers through portions of the device structure. Accordingly, the lower the mobility of charge carriers in a structural feature, the slower the device may function. One technique intended to increase charge carrier mobility includes increasing crystal lattice strain in semiconductive material. For example, conventional efforts include a variety of methods that increase tensile stress and thus increase charge carrier mobility. Other efforts to increase charge carrier mobility include substituting silicon in MOS devices with germanium. Germanium exhibits a lower band gap (0.85 eV) compared to silicon (1.1 eV), providing a higher drive current in MOS devices due to increased charge carrier mobility. However, germanium also exhibits significantly higher leakage currents and produces drain induced barrier lowering (DIBL), as known to those of ordinary skill. Other efforts to improve transistor devices include replacement of silicon dioxide gate dielectric materials with high K gate dielectric materials. In many devices, silicon dioxide dielectric has reached its scaling limit due to leakage currents. Excessive scaling allows leakage of charge carriers through silicon dioxide gate dielectric to the gate, significantly increasing power drain and adversely affecting operation of the transistor devices. High K gate dielectric materials might be used to decrease current leakage through the gate dielectric. However, high K dielectric materials used in combination with germanium exhibit poor interface properties at the interface between the high K gate dielectric and germanium-containing channel material. The gains in charge carrier mobility when using germanium with a high K dielectric material (such as shown in FIG. 4) do not produce the expected corresponding improvement in drive current. To date, efforts attempting to integrate high K dielectric in germanium MOS devices: have achieved limited success. Accordingly, a desire exists to use germanium in transistor devices in a manner taking greater advantage of the enhanced charge carrier mobility of germanium than previously obtained. Also, a further desire exists to incorporate the advantageous characteristics of high K gate dielectric materials with the enhanced charge carrier mobility of germanium. SUMMARY OF THE INVENTION According to one aspect of the invention, a transistor structure includes a first undoped, silicon-comprising channel layer over a substrate, a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer, and a second undoped, silicon-comprising channel layer over the buried channel. By way of example, the buried channel may be on and in contact with the first channel layer. Also, the second channel layer may be on and in contact with the buried channel. The second of the channel layers may consist of silicon and germanium. The first and second channel layers may consist of silicon. The structure may be comprised by a memory device. According to another aspect of the invention, a transistor structure includes a first channel layer over a substrate, a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer, and a second, undoped channel layer consisting of silicon and germanium over the buried channel. The buried channel exhibits charge carrier mobility greater than that of the first channel layer. According to a further aspect of the invention, a transistor structure includes a first channel layer over a substrate, a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer, and a second channel layer consisting of compositionally graded SiGe and, optionally, a dopant, the second channel layer being over the buried channel. The buried channel exhibits charge carrier mobility greater than that of the first channel layer. According to a still further aspect of the invention, a transistor structure includes a first silicon layer over a substrate, an undoped or homogeneously doped buried channel containing silicon and germanium over the first channel layer, and a second silicon layer over the buried channel. By way of example, the buried channel may be undoped and consist of silicon and germanium. Also, the first and second channel layers may consist of silicon. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described below with reference to the following accompanying drawings. FIG. 1 is a sectional view of a portion of a device including a buried channel according to one aspect of the invention. FIG. 2 is a sectional view of the device portion shown in FIG. 1 with an added gate dielectric and gate according to another aspect of the invention. FIG. 3 is an enlarged sectional view of selected structural features from FIG. 1 showing compositional grading according to a further aspect of the invention. FIG. 4 is a chart showing measured hole mobility for silicon with HfO2 gate dielectric/TaN gate (from Lee, et al., “Self-Aligned Ultra Thin HfO2 CMOS Transistors with High Quality CVD TaN Gate Electrode,” IEEE 2002 Symposium On VLSI Technology, pg. 82-83) compared to silicon with SiO2 gate dielectric (universal mobility curve) and germanium with HfO2 gate dielectric/TaN gate. FIG. 5 shows a diagrammatic view of computer illustrating an exemplary application of the present invention. FIG. 6 is a block diagram showing particular features of the motherboard of the FIG. 6 computer. FIG. 7 shows a high level block diagram of an electronic system according to an exemplary aspect of the present invention. FIG. 8 shows a simplified block diagram of an exemplary device according to an aspect of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS “Surface roughness scattering” or “scattering” in the context of the present document denotes an electron transport process whereby an electron in a particular crystal momentum state changes to a different state. Some may refer to it as a form of Coulombic scattering. Some speculation exists that high K dielectric materials produce a higher level of surface roughness scattering at the gate dielectric interface with underlying transistor channel material compared to surface roughness scattering for silicon dioxide gate dielectric on the same channel material. Scattering can hamper performance of the device. Accordingly, even though high K gate dielectric materials reduce current leakage incurred beyond the scaling limit of silicon dioxide, a reduction in surface roughness scattering may enhance performance of devices using a high K dielectric. In the context of the present document, “high K” refers to a K of greater than 3.9. Exemplary materials include HfO2 (K=25), HfO2Si, HfO2N, ZrO2 (K=25), Al2O3 (K=9), and others. Another performance enhancement involves inclusion of germanium in transistor channels. While germanium-containing channels exhibit improved drive currents, some speculation exists that germanium may diffuse across the interface between the gate dielectric and the underlying channel material. Also, very significant trap states appear to exist at the gate dielectric interface with the channel material. Acting as electrically active defects at the interface, the trap states are capable of trapping charge carriers. Despite the surface scattering problems, trap states, and germanium diffusion at the gate dielectric interface with a germanium channel, MOS devices using germanium according to the aspects of the invention are expected to exhibit promising, improved drive currents. The various aspects of the invention described herein may assist in countering the detrimental effects of combining high K gate dielectric material with germanium channel material and may thus produce performance gains in germanium MOS devices. The performance gains may be more commensurate with the gains in charge carrier mobility obtained by using germanium in the channel material. The various aspects of the invention may also produce performance gains in germanium MOS devices that do not use high K gate dielectric material or in other germanium-based transistors. Improvements in drive current of a transistor channel can be partly explained mathematically as follows: Ids=q×υinjection (Equation 1) where Ids is channel current, q is charge, and υinjection is transistor source injection velocity. “Charge” may be modified in Equation 1 to produce Equation 2: Ids=Cox×Gate Overdrive×υinjection (Equation 2) where Cox is gate capacitance. Equation 2 may be modified to produce Equation 3: Ids=Cox×(Vgs−Vt)×υinjection (Equation 3) showing that gate overdrive is simply the difference between gate-source voltage (Vgs) and threshold voltage (Vt). Final modification to produce Equation 4: Ids=Cox×(Vgs−Vt)×Esource×μinjection (Equation 4) where Esource is electric field at the source and μinjection is charge carrier mobility, displays in mathematical form some of the relationships discussed above. Namely, increasing gate capacitance (Cox) with high K dielectric material increases channel current (Ids). Also, increasing charge carrier mobility (μinjection) increases channel current. The increase in charge carrier mobility thus allows further scaling, reduces contact resistance, and lowers external resistance. As known to those of ordinary skill, “external resistance” refers to the resistance along a current path extending up to the transistor channel. In the context of the present document, external resistance includes contact resistance, plug or silicide resistance, diffusion region resistance, and spreading resistance in the overlap region (lightly doped drain). This demonstrates the desirability of using high K dielectric material and germanium channel material in transistors were it not for the surface scattering problems, trap states, germanium diffusion, and perhaps other problems encountered. Nevertheless, the various aspects of the invention address problems associated with germanium-containing channels and/or high K dielectric materials. According to one aspect of the invention, a transistor structure includes a first undoped, silicon-comprising channel layer over a substrate, a buried channel over the first channel layer, and a second undoped, silicon-comprising channel layer over the buried channel. The buried channel consists of germanium except that it may be doped or, preferably, undoped. In the context of the present document, “undoped” refers to a material having a dopant content of less than about 1×1015 atom/centimeter3 (atom/cm3). “Dopants” refers to impurities intentionally added to a material. “Impurities” refers to dopants as well as elements unintentionally added to a material. For example, conductivity enhancing “dopants” are frequently added to semiconductive material. A variety of “doping” techniques are known to those of ordinary skill. Also, while high purity materials are often desired, unintentional “impurities” may nevertheless accumulate in materials, usually with detrimental effect depending upon the degree of contamination. While preferably undoped, those of ordinary skill may choose to dope the buried channel (or other components) to provide some desired physical property. It is an advantage of the described transistor structure that it includes the germanium-containing buried channel between first and second silicon-comprising channel layers. In this manner, the difficulties associated with germanium-containing channels can be addresses by selecting suitable compositions for the first and/or second undoped, silicon-comprising channel layers. For example, at least the second of the undoped channel layers can consist of silicon and germanium. Further, at least one of the first and second channel layers may consist of compositionally graded SiGe having a higher Ge content at an interface with the buried channel in comparison to other portions of the first and second channel layers. As an alternative, the first and second channel layers may consist of silicon. The first and second channel layers can have thicknesses of from about 100 Angstroms to about 600 Angstroms. The buried channel can have a thickness of from about 300 Angstroms to about 600 Angstroms. As an example, the buried channel may exhibit charge carrier mobility greater than that of both the first and second channel layers. The buried channel may be on and in contact with the first channel layer. The second channel layer may be on and in contact with the buried channel. The substrate may include a semiconductor-on-insulator (SOI) substrate. The substrate can instead include a bulk silicon wafer. In the context of this document, the term “semiconductor substrate” or “semiconductive substrate” is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. The transistor structure may further include a gate dielectric layer having a K greater than 3.9 over the second-channel layer. The gate dielectric layer may have a K greater than about 10. The transistor structure may further include a gate over the second channel layer and a source and a drain in electrical connection with the buried channel. A thin buffer layer of from about 5 to about 10 Angstroms thickness may be provided between the gate dielectric layer and the second channel layer. The buffer layer may contain SiO2 and have a K of about 3.9. The buffer layer may assist in further minimizing surface roughness scattering and improving charge carrier mobility. FIG. 1 shows series of layers formed over substrate 10. Notably, a substrate 10 may include some number of optional layer(s), represented in FIG. 1 as optional layer 12, in accordance with the knowledge of those of ordinary skill. A first channel layer 14 is over substrate 10, a buried channel 16 is over first channel layer 14, and a second channel layer 18 is over buried channel 16. In FIG. 2, a gate dielectric 20 is over second channel layer 18 and a gate 22 is over gate dielectric 20. A source region 24 and a drain region 26 may be operationally proximate gate 22 and buried channel 16, in accordance with conventional configurations. Understandably, the buried channel transistor structure may be incorporated into a variety of conventional devices other than specifically shown in FIG. 2. Buried channel 16 may overcome difficulties associated with germanium-containing channels and take greater advantage of the enhanced charge carrier mobility of germanium. Also, buried channel 16 may overcome difficulties associated with incorporating the advantageous characteristics of high K gate dielectric materials with germanium-containing channels. Although a variety of more specific embodiments-are conceivable in accordance with the aspects of the invention described herein, a few stand out as particularly advantageous. For respective first channel layer, buried channel, and second channel layer, a Si/Ge/Si or SiGe/Ge/SiGe stack are possibilities. If the first or second undoped, silicon-comprising channel layer includes compositionally graded SiGe, then conventional methods may be used to form the layer with a composition reflected by the formula SixGe1-x, where x varies across a thickness of the first or second channel layer. FIG. 3 shows one example of compositional grading where first channel layer 14 and second channel layer 18 include four discrete layers, each with a different composition. Atomic layer deposition (ALD) is capable of forming monolayers with a single atom or molecule thickness. ALD and perhaps other known techniques may be used to form the FIG. 3 structures or similar structures described herein. As one possibility, layers 14a and 18a may have a composition described by the formula SixGe1-x where x is 0.25. Layers 14b and 18b may have a composition where x is 0.5, layers 14c and 18c may have a composition where x is 0.75 and layers 14d and 18d may have a composition where x is 1. Accordingly, x may be from 0 to 1. Each of the four discrete layers that comprise first channel layer 14 and second channel layer 18 may be monolayers or multiple monolayers. Understandably, first channel layer 14 and second channel layer 18 may include at least two sub-layers of discretely different compositions. In accordance with the various embodiments, buried channel 16 thus may offer a low resistance path for charge carriers between first channel layer 14 and second channel layer 16 while diminishing the problem of trap states and germanium diffusion associated with germanium-containing channels. Buried channel may also diminish the problem of surface roughness scattering associated with a high K dielectric-to-germanium interface. Conventional doping and engineering of the germanium mole fraction in first channel layer 14 and second channel layer 18 can assist in controlling drain induced barrier lowering. According to another aspect of the invention, a transistor structure includes a first channel layer over a substrate, a buried channel layer over the first channel layer, and a second, undoped channel layer consisting essentially of silicon and germanium over the buried channel. The buried channel consists of germanium and, optionally, a dopant and exhibits charge carrier mobility greater than that of the first channel layer. As one example, the buried channel may consist of germanium (thereby being undoped). The first channel layer may consist of silicon, germanium, and, optionally, a dopant. According to a further aspect of the invention, a transistor structure includes a first channel layer over a substrate, a buried channel over the first channel layer, and a second channel layer over the buried channel. The buried channel consists of germanium and, optionally, a dopant and exhibits charge carrier mobility greater than that of the first channel layer. The second channel layer consists of compositionally graded SiGe and, optionally, a dopant. As one example, the first channel layer may consist of silicon, germanium, and, optionally, a dopant. The buried channel may consist of germanium and both the first and second channel layers may be undoped. Preferably, both the first and second channel layers are doped. According to a still further aspect of the invention, a transistor includes a first channel over a substrate, a buried channel consisting of germanium on and in contact with the first channel layer, and a second channel layer on and in contact with the buried channel. The first and second channel layers consist of compositionally graded SiGe and, optionally, a dopant. The first and second channel layers have higher Ge content at an interface with the buried channel in comparison to other portions of the first and second channel layers. The buried channel exhibits charge carrier mobility greater than that of both the first and second channel layers. The transistor further includes a gate dielectric layer having a K greater than 3.9 over the second channel layer, a gate over the gate dielectric layer, and a source and a drain in electrical connection with the buried channel. As an example, dopants in the first channel layer need not be the same as dopants in the second channel layer, but may be the same. Significant advantages may exist in providing a germanium channel between first and second channel layers containing doped, compositionally graded SiGe. Without being limited to any particular theory, it is believed that very high vertical electrical fields, typically present when using a high K gate dielectric, quantize the charge carriers within the inversion region of the transistor channel. The inversion region forms where the concentration of minority charge carriers exceeds that of majority charge carriers, typically in the channel near the interface with the gate dielectric. In the present aspect of the invention, the inversion region can thus form in the graded SiGe where the Ge content provides improved minority carrier mobility in comparison to Si, creating 2D electron gas. Also, at least two sub-bands are expected to form in the graded SiGe. Such sub-bands form more readily in SiGe compared to Si. The lower sub-band provides a lower effective mass for charge carriers, enabling very high mobility and allowing ballistic, or close-to-ballistic, charge carrier transport. Sub-band formation is believed to occur as a result of shifting the X-minima of the Brillouin zone symmetry point closer to the Γ-point in the band structure. (As known to those of ordinary skill, crystal properties of silicon may be described in terms of a Brillouin zone having planes that define the location of the band gap. The Brillouin zone exhibits major symmetry points, such as the X symmetry point. In a graphical depiction of band structure (energy-momentum dispersion relationship) in silicon, the X symmetry point corresponds to conduction band minima, or X-minima. The Γ-point corresponds to valence band maxima.) Further, the wave function of charge carriers is believed to go to zero near the graded SiGe/gate dielectric interface due to the charge carrier quantization mentioned above. Accordingly, charge carriers from the transistor source can be pushed further into the buried channel structure. The germanium buried channel may be formed at a distance from the transistor source that maximizes injection velocity into the channel region, leading to high drive currents. Preferably, a distance from a gate dielectric/channel interface to the germanium buried channel is from about 50 to about 100 Angstroms. As is apparent from the discussion above, the carrier quantization, sub-band formation, and increased injection velocity attainable with the graded SiGe/Ge/graded SiGe structure contribute to significant performance improvements. In addition, dopant engineering of the graded SiGe under the buried channel can assist in confining charge carriers close to the buried channel. Conventionally, dopant implants create a dopant profile through an elevational thickness of the implanted material. Dopant concentration as a function of depth into the implanted material can form a Gaussian (normal) distribution or Pearson (skewed) distribution. In either case, the peak dopant concentration and width of the distribution (i.e., depth into the material) may be engineered by varying dose and energy using conventional techniques. In the aspects of the present invention, the dopant profile may reach its peak within the buried channel and drop-off on each side of the peak to a sufficient degree such that conduction of charge carriers through the buried channel instead of the first and/or second channel layer is significantly favored. This dopant condition can advantageously influence a device's on and off characteristics. Providing graded SiGe as the second channel layer may create important advantages in comparison to SiGe of uniform composition throughout an elevational thickness of the second channel layer. If gate dielectric is formed on the second channel layer containing compositionally uniform SiGe, then the quality of gate dielectric/channel interface depends upon the uniform SiGe. In this circumstance, additional Ge content increasingly degrades the interface quality. Typically, the density of interface trap states, surface roughness, etc. worsens with additional Ge content. By comparison, graded SiGe can minimize the trap density, surface roughness, etc. As indicated above, the graded SiGe composition may be reflected by the formula SixGe1-x, where x varies across a thickness of the second channel layer. The value for x may be 1 at the gate dielectric/channel interface, providing an interface quality similar to that of silicon channel. Even if the value for x is less than 1 at the interface, x may be selected to provide a better quality interface compared to uniform SiGe with higher Ge content. The embodiments discussed thus far address a buried channel consisting of germanium and optional dopants. However, aspects of the invention also include an undoped or homogeneously doped buried channel containing both silicon and germanium. Accordingly, in one aspect of the invention a transistor structure includes a first silicon layer over a substrate, an undoped or homogeneously doped buried channel containing silicon and germanium over the first channel layer, and a second silicon layer over the buried channel. The variations in such a transistor structure are similar to those described above for a buried channel consisting of germanium and optional dopants. For example, the buried channel may exhibit charge carrier mobility greater than that of both the first and second silicon layers. The buried channel is preferably undoped. The buried channel may be on and in contact with the first channel layer. The second channel layer may be on and in contact with the buried channel. The first and second channel layers may consist of silicon. The first and second channel layers may have thicknesses of from about 100 Angstroms to about 600 Angstroms. The buried channel may have a thickness of from about 300 Angstroms to about 600 Angstroms. The substrate may include a SOI substrate. The substrate may instead include a bulk silicon wafer. In the circumstance where the transistor structure further includes a high K gate dielectric layer over the second channel layer, it is advantageous to provide the second silicon layer between the gate dielectric layer and the buried channel including silicon and germanium. The advantages are similar to those described herein for a second channel layer between a buried channel including germanium and a high K gate dielectric layer. Even for a buried channel including silicon and germanium, the second silicon layer addresses the problems of trap states and germanium diffusion at the gate dielectric interface with a germanium-containing channel. The second silicon layer also addresses the problem of surface roughness scattering at a high K dielectric interface with a germanium-containing channel. Understandably, surface roughness scattering may be less of a problem given the partial silicon content of the buried channel. Preferably, the buried channel including silicon and germanium exhibits a composition of SiyGe1-y, where y is from 0.2 to 0.8 or, preferably, from 0.3 to 0.5. In another aspect of the invention, a transistor includes a first channel layer over a substrate, an undoped or homogeneously doped buried channel on and in contact with the first channel layer, and a second channel layer on and in contact with the buried channel. The first and second channel layers consist of silicon and, optionally, a dopant. The buried channel consists of silicon and germanium aside from the dopants, if any. The transistor includes a gate dielectric layer having a K greater than 3.9 over the second channel layer, a gate over the gate dielectric layer, and a source and a drain in electrical connection with the buried channel. The buried channel exhibits charge carrier mobility greater than that of both the first and second channel layers. At least three embodiments of the aspects of the invention stand out as being of a particular advantage. In a first embodiment, a first channel layer, buried channel, and second channel layer respectively include SiGe/Ge/SiGe, where at least the second of the channel layers may be compositionally graded, undoped, or both. In a second embodiment, the respective layers include Si/Ge/Si. In a third embodiment, the respective layers include Si/SiGe/Si, where the buried channel is undoped or homogeneously doped, that is, does not rely upon modulation doping. FIG. 5 illustrates generally, by way of example, but not by way of limitation, an embodiment of a computer system 400 according to an aspect of the resent invention. Computer system 400 includes a monitor 401 or other communication output device, a keyboard 402 or other communication input device, and a motherboard 404. Motherboard 404 can carry a microprocessor 406 or other data processing unit, and at least one memory device 408. Memory device 408 can comprise various aspects of the invention described above. Memory device 408 can comprise an array of memory cells, and such array can be coupled with addressing circuitry for accessing individual memory cells in the array. Further, the memory cell array can be coupled to a read circuit for reading data from the memory cells. The addressing and read circuitry can be utilized for conveying information between memory device 408 and processor 406. Such is illustrated in the block diagram of the motherboard 404 shown in FIG. 6. In such block diagram, the addressing circuitry is illustrated as 410 and the read circuitry is illustrated as 412. In particular aspects of the invention, memory device 408 can correspond to a memory module. For example, single in-line memory modules (SIMMs) and dual in-line memory modules (DIMMs) may be used in the implementation that utilizes the teachings of the present invention. The memory device can be incorporated into any of a variety of designs that provide different methods of reading from and writing to memory cells of the device. One such method is the page mode operation. Page mode operations in a DRAM are defined by the method of accessing a row of a memory cell arrays and randomly accessing different columns of the array. Data stored at the row and column intersection can be read and output while that column is accessed. An alternate type of device is the extended data output (EDO) memory that allows data stored at a memory array address to be available as output after the addressed column has been closed. This memory can increase some communication speeds by allowing shorter access signals without reducing the time in which memory output data is available on a memory bus. Other alternative types of devices include SDRAM, DDR SDRAM, SLDRAM, VRAM and Direct RDRAM, as well as others such as SRAM or Flash memories. FIG. 7 illustrates a simplified block diagram of a high-level organization of various embodiments of an exemplary electronic system 700 of the present invention. System 700 can correspond to, for example, a computer system, a process control system, or any other system that employs a processor and associated memory. Electronic system 700 has functional elements, including a processor or arithmetic/logic unit (ALU) 702, a control unit 704, a memory device unit 706 and an input/output (I/O) device 708. Generally, electronic system 700 will have a native set of instructions that specify operations to be performed on data by the processor 702 and other interactions between the processor 702, the memory device unit 706 and the 1/0 devices 708. The control unit 704 coordinates all operations of the processor 702, the memory device 706 and the I/O devices 708 by continuously cycling through a set of operations that cause instructions to be fetched from the memory device 706 and executed. In various embodiments, the memory device-706 includes, but is not limited to, random access memory (RAM) devices, read-only memory (ROM) devices, and peripheral devices such as a floppy disk drive and a compact disk CD-ROM drive. One of ordinary skill in the art will understand, upon reading and comprehending this disclosure, that any of the illustrated electrical components are capable of being fabricated to include DRAM cells in accordance with various aspects of the present invention. FIG. 8 is a simplified block diagram of a high-level organization of various embodiments of an exemplary electronic system 800. The system 800 includes a memory device 802 that has an array of memory cells 804, address decoder 806, row access circuitry 808, column access circuitry 810, read/write control circuitry 812 for controlling operations, and input/output circuitry 814. The memory device 802 further includes power circuitry 816, and sensors 820, such as current sensors for determining whether a memory cell is in a low-threshold conducting state or in a high-threshold non-conducting state. The illustrated power circuitry 816 includes power supply circuitry 880, circuitry 882 for providing a reference voltage, circuitry 884 for providing the first wordline with pulses, circuitry 886 for providing the second wordline with pulses, and circuitry 888 for providing the bitline with pulses. The system 800 also includes a processor 822, or memory controller for memory accessing. The memory device 802 receives control signals 824 from the processor 822 over wiring or metallization lines. The memory device 802 is used to store data that is accessed via I/O lines. It will be appreciated by those skilled in the art that additional circuitry and control signals can be provided, and that the memory device 802 has been simplified to help focus on the invention. At least one of the processor 822 or memory device 802 can include a capacitor construction in a memory device of the type described previously herein. The various illustrated systems of this disclosure are intended to provide a general understanding of various applications for the circuitry and structures of the present invention, and are not intended to serve as a complete description of all the elements and features of an electronic system using memory cells in accordance with aspects of the present invention. One of ordinary skill in the art will understand that the various electronic systems can be fabricated in single-package processing units, or even on a single semiconductor chip, in order to reduce the communication time between the processor and the memory device(s). Applications for memory cells can include electronic systems for use in memory modules, device drivers, power modules, communication modems, processor modules, and application-specific modules, and may include multilayer, multichip modules. Such circuitry can further be a subcomponent of a variety of electronic systems, such as a clock, a television, a cell phone, a personal computer, an automobile, an industrial control system, an aircraft, and others. In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Operation of semiconductor devices typically depends upon movement of charge carriers through portions of the device structure. Accordingly, the lower the mobility of charge carriers in a structural feature, the slower the device may function. One technique intended to increase charge carrier mobility includes increasing crystal lattice strain in semiconductive material. For example, conventional efforts include a variety of methods that increase tensile stress and thus increase charge carrier mobility. Other efforts to increase charge carrier mobility include substituting silicon in MOS devices with germanium. Germanium exhibits a lower band gap (0.85 eV) compared to silicon (1.1 eV), providing a higher drive current in MOS devices due to increased charge carrier mobility. However, germanium also exhibits significantly higher leakage currents and produces drain induced barrier lowering (DIBL), as known to those of ordinary skill. Other efforts to improve transistor devices include replacement of silicon dioxide gate dielectric materials with high K gate dielectric materials. In many devices, silicon dioxide dielectric has reached its scaling limit due to leakage currents. Excessive scaling allows leakage of charge carriers through silicon dioxide gate dielectric to the gate, significantly increasing power drain and adversely affecting operation of the transistor devices. High K gate dielectric materials might be used to decrease current leakage through the gate dielectric. However, high K dielectric materials used in combination with germanium exhibit poor interface properties at the interface between the high K gate dielectric and germanium-containing channel material. The gains in charge carrier mobility when using germanium with a high K dielectric material (such as shown in FIG. 4 ) do not produce the expected corresponding improvement in drive current. To date, efforts attempting to integrate high K dielectric in germanium MOS devices: have achieved limited success. Accordingly, a desire exists to use germanium in transistor devices in a manner taking greater advantage of the enhanced charge carrier mobility of germanium than previously obtained. Also, a further desire exists to incorporate the advantageous characteristics of high K gate dielectric materials with the enhanced charge carrier mobility of germanium.
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<SOH> SUMMARY OF THE INVENTION <EOH>According to one aspect of the invention, a transistor structure includes a first undoped, silicon-comprising channel layer over a substrate, a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer, and a second undoped, silicon-comprising channel layer over the buried channel. By way of example, the buried channel may be on and in contact with the first channel layer. Also, the second channel layer may be on and in contact with the buried channel. The second of the channel layers may consist of silicon and germanium. The first and second channel layers may consist of silicon. The structure may be comprised by a memory device. According to another aspect of the invention, a transistor structure includes a first channel layer over a substrate, a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer, and a second, undoped channel layer consisting of silicon and germanium over the buried channel. The buried channel exhibits charge carrier mobility greater than that of the first channel layer. According to a further aspect of the invention, a transistor structure includes a first channel layer over a substrate, a buried channel consisting of germanium and, optionally, a dopant, the buried channel being over the first channel layer, and a second channel layer consisting of compositionally graded SiGe and, optionally, a dopant, the second channel layer being over the buried channel. The buried channel exhibits charge carrier mobility greater than that of the first channel layer. According to a still further aspect of the invention, a transistor structure includes a first silicon layer over a substrate, an undoped or homogeneously doped buried channel containing silicon and germanium over the first channel layer, and a second silicon layer over the buried channel. By way of example, the buried channel may be undoped and consist of silicon and germanium. Also, the first and second channel layers may consist of silicon.
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20040630
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20061219
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20060105
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69297.0
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H01L31062
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MALSAWMA, LALRINFAMKIM HMAR
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Transistor structures and transistors with a germanium-containing channel
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UNDISCOUNTED
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ACCEPTED
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H01L
| 2,004
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10,882,570
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ACCEPTED
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Antimicrobial and antistatic polymers and methods of using such polymers on various substrates
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The present invention relates to a substrate having antimicrobial and/or antistatic properties. Such properties are imparted by applying a coating or film formed from a cationically-charged polymer composition. The polymer composition includes a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition, and a steric stabilization component incorporated into the cationically-charged polymer composition. The present invention also relates to a polymeric material comprising a base polymer blended with the above cationically-charged polymer composition.
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1. A substrate having applied thereto a coating or film to provide antimicrobial and/or antistatic properties, said coating or film formed from a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition and a steric stabilization component incorporated into the cationically-charged polymer composition. 2. The substrate according to claim 1, wherein the substrate is selected from the group consisting of non-woven and woven fabrics; organic and inorganic particulates, fibers and agglomerates; foams; films; cellulosic materials; metal; and plastic. 3. The substrate according to claim 1, wherein the noncationic ethylenically unsaturated monomer is selected from the group consisting of vinyl aromatic monomers; olefins; aliphatic conjugated diene monomers; non-aromatic unsaturated mono- or dicarboxylic ester monomers; monomers based on the half ester of an unsaturated dicarboxylic acid monomer; unsaturated mono- or dicarboxylic acid monomers and derivatives thereof; nitrogen-containing monomers; phosphorous-containing monomers; sulfur-containing monomers; and vinyl ester monomers. 4. The substrate according to claim 1, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises an amine or amide monomer. 5. The substrate according to claim 1, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternized amine monomer. 6. The substrate according to claim 1, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternary derivative capable of providing hydrophobicity to the polymer composition. 7. The substrate according to claim 1, wherein the steric stabilization component is a monomer having alkoxylated functionality or is a protective colloid. 8. The substrate according to claim 7, wherein the monomer having alkoxylated functionality is selected from the group consisting of (a) CH2═C(R)COO(CH2CHR′O)nR″—where R═H, C1-C4 alkyl; and R′═H, C1-C4 alkyl, and R″═H, C1-C12alkyl, and n=1-30; or CH2═C(R)COO(CH2CH2O)n(CH2CHR′O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, n and m each may range from 1-15; and CH2═C(R)COO(CH2CHR′O)n(CH2CH2O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl and R″═H, C1-C12 alkyl, n and m=1-15, and (d) mixtures of (a) and (b). 9. The substrate according to claim 1, wherein the steric stabilization component is a polymerizable surfactant. 10. The substrate according to claim 1, wherein the polymer composition further includes up to about 1.0 weight percent of a nonionic surfactant. 11. The substrate according to claim 1, wherein the polymer composition further includes an antimicrobial agent or antistatic agent. 12. The substrate according to claim 11, wherein the antimicrobial agent is a chitosan-based material. 13. The substrate according to claim 11, wherein the antimicrobial agent is a metal biocide selected from the group consisting of silver and zinc, and salts and oxides thereof. 14. The substrate according to claim 11, wherein the antistatic agent is selected from the group consisting of nitrogen compounds, esters of fatty acids and their derivatives, polyhydric alcohols and their derivatives, phosphoric acid derivatives, solutions of electrolytes in liquids with high dielectric constants, metal salts and oxides, metals, carbon black, carbon nanotubes and semiconductors. 15. The substrate according to claim 11, wherein the antimicrobial agent is undecylenic acid or alcohol or a reaction product of undecylenic acid with hydroxyl or acid containing material having ethylenic unsaturation. 16. A substrate having applied thereto a coating or film to provide antimicrobial and/or antistatic properties, said coating or film formed from a cationically-charged polymer composition consisting essentially of about 20 to about 99 weight percent of a noncationic ethylenically unsaturated monomer, about 0.5 to about 75 weight percent of an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition, about 0.5 to about 75 weight percent of a steric stabilization monomer, and 0 to 1.0 weight percent of a nonionic surfactant, wherein cationically-charged polymer composition is devoid of cationic and anionic surfactants. 17. The substrate according to claim 16, wherein the substrate is selected from the group consisting of non-woven and woven fabrics; organic and inorganic particulates, fibers and agglomerates; foams; films, cellulosic materials; concrete, masonry; glass; metal; and plastic. 18. The substrate according to claim 16, wherein the noncationic ethylenically unsaturated monomer is selected from the group consisting of vinyl aromatic monomers; olefins; aliphatic conjugated diene monomers; non-aromatic unsaturated mono- or dicarboxylic ester monomers; monomers based on the half ester of an unsaturated dicarboxylic acid monomer; unsaturated mono- or dicarboxylic acid monomers and derivatives thereof; nitrogen-containing monomers; phosphorous-containing monomers; sulfur-containing monomers; and vinyl ester monomers. 19. The substrate according to claim 16, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises an amine or amide monomer. 20. The substrate according to claim 16, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternized amine monomer. 21. The substrate according to claim 16, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternary derivative capable of providing hydrophobicity to the polymer composition. 22. The substrate according to claim 16, wherein the steric stabilization component is a monomer having alkoxylated functionality or is a protective colloid. 23. The substrate according to claim 22, wherein the monomer having alkoxylated functionality is selected from the group consisting of (a) CH2═C(R)COO(CH2CHR′O)nR″—where R═H, C1-C4 alkyl; and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, and n=1-30; or CH2═C(R)COO(CH2CH2O)n(CH2CHR′O)mR″—where R═H C1-C4 alkyl, and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, n and m each may range from 1-15; and CH2═C(R)COO(CH2CHR′O)n(CH2CH2O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl and R″═H, C1-C12 alkyl, n and m=1-15, and (d) mixtures of (a) and (b). 24. The substrate according to claim 16, wherein the steric stabilization component is a polymerizable surfactant. 25. The substrate according to claim 16, wherein the polymer composition further includes an antimicrobial agent or antistatic agent. 26. The substrate according to claim 25, wherein the antimicrobial agent is a chitosan-based material. 27. The substrate according to claim 25, wherein the antimicrobial agent is a metal biocide selected from the group consisting of silver and zinc, and salts and oxides thereof. 28. The substrate according to claim 25, wherein the antistatic agent is selected from the group consisting of nitrogen compounds, esters of fatty acids and their derivatives, polyhydric alcohols and their derivatives, phosphoric acid derivatives, solutions of electrolytes in liquids with high dielectric constants, metallic salts and oxides, metals, carbon black, carbon nanotubes and semiconductors. 29. The substrate according to claim 25, wherein the antimicrobial agent is undecylenic acid or alcohol or a reaction product of undecylenic acid with hydroxyl or acid containing material having ethylenic unsaturation. 30. A polymeric material having antimicrobial and/or antistatic properties, said polymer material comprising a base polymer blended with a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition and a steric stabilization component incorporated into the cationically-charged polymer composition. 31. The polymeric material according to claim 30, wherein said base polymer is selected from the group consisting of polyurethanes, phenolics, polyesters, polyolefins, polyamides, polycarbonates, polyethers, polyether-amides, polyether-imides, polyorganosilanes, polysulfones, polyisoprene, polychloroprene, acrylics, styrene-butadienes, styrene acrylonitriles, ABS, EVA, polytetrafluoroethylene, polyether-esters, and polyepoxides. 32. The polymeric material according to claim 30, wherein the polymeric material is a solid. 33. The polymeric material according to claim 30, wherein the polymeric material is a foam. 34. The polymeric material according to claim 30, wherein the noncationic ethylenically unsaturated monomer is selected from the group consisting of vinyl aromatic monomers; olefins; aliphatic conjugated diene monomers; non-aromatic unsaturated mono- or dicarboxylic ester monomers; monomers based on the half ester of an unsaturated dicarboxylic acid monomer; unsaturated mono- or dicarboxylic acid monomers and derivatives thereof; nitrogen-containing monomers; phosphorous-containing monomers; sulfur-containing monomers; and vinyl ester monomers. 35. The polymeric material according to claim 30, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises an amine or amide monomer. 36. The polymeric material according to claim 30, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternized amine monomer. 37. The polymeric material according to claim 30, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternary derivative capable of providing hydrophobicity to the polymer composition. 38. The polymeric material according to claim 30, wherein the steric stabilization component is a monomer having alkoxylated functionality or is a protective colloid. 39. The polymeric material according to claim 38, wherein the monomer having alkoxylated functionality is selected from the group consisting of (a) CH2═C(R)COO(CH2CHR′O)nR″—where R═H, C1-C4 alkyl; and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, and n=1-30; or CH2═C(R)COO(CH2CH2O)n(CH2CHR′O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, n and m each may range from 1-15; and CH2═C(R)COO(CH2CHR′O)n(CH2CH2O)mR═—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl and R″═H, C1-C12 alkyl, n and m=1-15, and (d) mixtures of (a) and (b). 40. The polymeric material according to claim 30, wherein the polymer composition further includes up to about 1.0 weight percent of a nonionic surfactant. 41. The polymeric material according to claim 30, wherein the polymer composition further includes an antimicrobial agent or antistatic agent. 42. The polymeric material according to claim 41, wherein the antimicrobial agent is a chitosan material. 43. The polymeric material according to claim 41, wherein the antimicrobial agent is a metal biocide selected from the group consisting of silver and zinc, and salts and oxides thereof. 44. The polymeric material according to claim 41, wherein the antistatic agent is selected from the group consisting of nitrogen compounds, esters of fatty acids and their derivatives, polyhydric alcohols and their derivatives, phosphoric acid derivatives, solutions of electrolytes in liquids with high dielectric constants, metallic salts and oxides, metals, carbon black, carbon nanotubes and semiconductors. 45. The polymeric material according to claim 41, wherein the antimicrobial agent is undecylenic acid or alcohol or a reaction product of undecylenic acid with hydroxyl or acid containing material having ethylenic unsaturation. 46. A polymer material having antimicrobial and/or antistatic properties, said polymeric material comprising a base polymer blended with a cationically-charged polymer composition consisting essentially of about 20 to about 99 weight percent of a noncationic ethylenically unsaturated monomer, about 0.5 to about 75 weight percent of an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition, about 0.5 to about 75 weight percent of a steric stabilization monomer and 0 to 1.0 weight percent of a nonionic surfactant, wherein cationically-charged polymer composition is devoid of cationic and anionic surfactants. 47. The polymeric material according to claim 46, wherein the noncationic ethylenically unsaturated monomer is selected from the group consisting of vinyl aromatic monomers; olefins; aliphatic conjugated diene monomers; non-aromatic unsaturated mono- or dicarboxylic ester monomers; monomers based on the half ester of an unsaturated dicarboxylic acid monomer; unsaturated mono- or dicarboxylic acid monomers and derivatives thereof; nitrogen-containing monomers; phosphorous-containing monomers; sulfur-containing monomers; and vinyl ester monomers. 48. The polymeric material according to claim 46, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises an amine or amide monomer. 49. The polymeric material according to claim 46, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternized amine monomer. 50. The polymeric material according to claim 46, wherein the ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition comprises a quaternary derivative capable of providing hydrophobicity to the polymer composition. 51. The polymeric material according to claim 46, wherein the steric stabilization component is a monomer having alkoxylated functionality or is a protective colloid. 52. The polymeric material according to claim 51, wherein the monomer having alkoxylated functionality is selected from the group consisting of (a) CH2═C(R)COO(CH2CHR′O)nR″—where R═H, C1-C4 alkyl; and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, and n=1-30; or CH2═C(R)COO(CH2CH2O)n(CH2CHR′O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, n and m each may range from 1-15; and CH2═C(R)COO(CH2CHR′O)n(CH2CH2O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl and R″═H, C1-C12 alkyl, n and m=1-15, and (d) mixtures of (a) and (b). 53. The polymeric material according to claim 46, wherein the polymer composition further includes an antimicrobial agent or antistatic agent. 54. The polymeric material according to claim 53, wherein the antimicrobial agent is a chitosan material. 55. The polymeric material according to claim 53, wherein the antimicrobial agent is a metal biocide selected from the group consisting of silver and zinc, and salts and oxides thereof. 56. The polymeric material according to claim 53, wherein the antistatic agent is selected from the group consisting of nitrogen compounds, esters of fatty acids and their derivatives, polyhydric alcohols and their derivatives, phosphoric acid derivatives, solutions of electrolytes in liquids with high dielectric constants, metallic salts and oxides, metals, carbon black, carbon nanotubes and semiconductors. 57. The polymeric material according to claim 53, wherein the antimicrobial agent is undecylenic acid, or alcohol or a reaction product of undecylenic acid with hydroxyl or acid containing material having ethylenic unsaturation. 58. The polymeric material according to claim 53, wherein said base polymer is selected from the group consisting of polyurethanes, phenolics, polyesters, polyolefins, polyamides, polycarbonates, polyethers, polyether-amides, polyether-imides, polyorganosilanes, polysulfones, polyisoprene, polychloroprene, acrylics, styrene-butadienes, styrene acrylonitriles, ABS, EVA, polytetrafluoroethylene, polyether-esters, and polyepoxides. 59. The polymeric material according to claim 53, wherein the polymeric material is a solid. 60. The polymeric material according to claim 53, wherein the polymeric material is a foam. 61. A method of providing antimicrobial and/or antistatic properties to a substrate comprising applying a cationically-charged polymer composition to the substrate, wherein the polymer composition comprises a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition and a steric stabilization component incorporated into the cationically-charged polymer composition. 62. A method imparting antimicrobial and/or antistatic properties to a polymeric material, the method comprising blending a base polymer with a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition and a steric stabilization component incorporated into the cationically-charged polymer composition.
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RELATED APPLICATION This application claims priority to U.S. Provisional Application Ser. No. 60/484,745, filed Jul. 3, 2003, the contents of which are hereby incorporated by reference as if recited in full herein. FIELD AND BACKGROUND OF THE INVENTION The present invention relates to polymers having inherent antimicrobial or antistatic properties. Such polymers can be applied or used in conjunction with a wide variety of substrates (e.g., textiles, metal, cellulosic materials, plastics, etc.) to provide the substrate with antimicrobial and/or antistatic properties. In addition, the polymers can also be combined with other polymers (e.g., the polymers of the invention can be used as additives) to provide such other polymers with antimicrobial and/or antistatic properties. Various bacteria, fungi, viruses, algae and other microorganisms are known to be in the environment and to potentially adversely affect people coming in contact with them. Such microorganisms are often undesirable as a cause of illness, odors and damage to a wide variety of material and substrates. In order to combat such microorganisms, antimicrobial agents have been suggested. However, there is also a need for such agents to be both sustainable and to be compatible, and to be used on and with a wide variety of polymer materials and substrates. Various additives and polymer systems have been suggested as providing antimicrobial properties. See, for example, U.S. Pat. No. 3,872,128 to Byck, U.S. Pat. No. 5,024,840 to Blakely et al, U.S. Pat. No. 5,290,894 to Malrose et al, U.S. Pat. No. 5,967,714, 6,203,856 and U.S. Pat. No. 6,248,811 to Ottersbach et al, U.S. Pat. No. 6,194,530 to Klasse et al. and U.S. Pat. No. 6,242,526 to Siddiqui et al. With respect to antistatic properties, various substrates tend to accumulate static electrical charge due to low electrical conductivity. This is particularly problematic with plastic substrates. Such accumulation can adversely affect processing, cause electrical damage (e.g., in semiconductor devices), provide a fire hazard through the formation of an electrical arc, and exposes personnel handling the substrate to electrical shock. Various solutions to such static buildup have been suggested. See, for example, U.S. Pat. No. 4,029,694 and U.S. Pat. No. 4,093,676 to Weipert et al, U.S. Pat. No. 4,098,842 to Login, U.S. Pat. No. 4,857,590 to Gaggar et al. and U.S. Pat. No. 4,859,727 to Sasaki et al. There, however, remains a need for potentially less toxic polymer compositions that provide sustainable antimicrobial and/or antistatic properties to a wide variety of substrates and materials. SUMMARY OF THE INVENTION The present invention relates to a substrate having antimicrobial and/or antistatic properties. Such properties are imparted by applying a coating or film formed from a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition, and a steric stabilization component incorporated into the cationically-charged polymer composition. The present invention also relates to a polymeric material comprising a base polymer blended with a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated cationic monomer capable of providing a cationic charge to the polymer composition, and a steric stabilization component incorporated into the cationically-charged polymer composition. The present invention also relates to a method of providing antimicrobial and/or antistatic properties to a substrate. The method includes the step of applying the cationically-charged polymer composition described above to a substrate. The present invention also relates to a method of imparting antimicrobial and/or antistatic properties to a polymer material. The method includes the step of blending a base polymer with the cationically-charged polymer composition described above. DETAILED DESCRIPTION OF THE INVENTION In the following detailed description, embodiments of the present invention are described in detail to enable practice of the invention. Although the invention is described with reference to these specific embodiments, it is understood that the invention is not limited to these embodiments. The invention includes numerous alternatives, modifications, and equivalents as will become apparent from consideration of the following detailed description. As summarized above, the present invention utilizes a cationically-charged polymer composition to impart or provide antimicrobial and/or antistatic properties to a substrate or to be blended with a base polymer to provide a polymer material having antimicrobial and/or antistatic properties. The cationically-charged polymer composition includes a noncationic ethylenically unsaturated monomer an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition, and a steric stabilization component. Suitable substrates include, but are not limited to fabrics (both woven and non-woven), organic and inorganic particulates, fibers and agglomerates; foams; films; cellulosic material (e.g., paper or wood); metal; concrete; masonry; glass; and plastics, both thermoset and thermoplastic. Various noncationic ethylenically unsaturated monomers may be used in the composition. Examples of monomers can be found in U.S. patent application Ser. No. 09/370,395 filed Aug. 6, 1999 and U.S. Pat. No. 5,830,934 to Krishnan, the disclosures of which are incorporated herein by reference in their entirety. Such monomers include, but are not limited to, vinyl aromatic monomers (e.g., styrene, para methyl styrene, chloromethyl styrene, vinyl toluene); olefins (e.g., ethylene); aliphatic conjugated diene monomers (e.g., butadiene); non-aromatic unsaturated mono- or dicarboxylic ester monomers (e.g., methyl methacrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, glycidyl methacrylate, isodecyl acrylate, lauryl acrylate); monomers based on the half ester of an unsaturated dicarboxylic acid monomer (e.g., monomethyl maleate); unsaturated mono- or dicarboxylic acid monomers and derivatives thereof (e.g., itaconic acid); nitrogen-containing monomers (e.g., acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-methylol acrylamide, N-(isobutoxymethyl) acrylamide); phosphorus-containing monomers; sulfur-containing monomers (e.g. styrene sulfonate); and vinyl ester monomers which includes branched vinyl esters (e.g., vinyl neodecanoate, vinyl versatates). Fluorinated analogs of alkyl acrylates or methacrylates may also be used. Mixtures of the above may be used. The composition preferably comprises from about 20 to about 99 percent of the noncationic ethylenically unsaturated monomer based on the total monomer weight. The composition also includes an ethylenically unsaturated cationic monomer capable of providing a cationic charge to the polymer composition. The cationic monomer is incorporated into the polymer composition by virtue of its ethylenic unsaturation. For the purposes of the invention, the term “cationic monomer” refers to any monomer which possesses or can be altered to provide a net positive charge. For example, this positive charge may be imparted by a heteroatom which is present in the monomer. Exemplary heteroatoms include, but are not limited to, nitrogen, sulfur, and phosphorus. Examples of cationic monomers include amine and amide monomers, and quaternary amine monomers. Amine and amide monomers include, but are not limited to: dimethylaminoethyl acrylate; diethylaminoethyl acrylate; dimethyl aminoethyl methacrylate; diethylaminoethyl methacrylate; tertiary butylaminoethyl methacrylate; N,N-dimethyl acrylamide; N,N-dimethylaminopropyl acrylamide; acryloyl morpholine; N-isopropyl acrylamide; N,N-diethyl acrylamide; dimethyl aminoethyl vinyl ether; 2-methyl-1-vinyl imidazole; N,N-dimethylaminopropyl methacrylamide; vinyl pyridine; vinyl benzyl amine methyl chloride quarternary; dimethylaminoethyl methacrylate methyl chloride quaternary; diallyldimethylammonium chloride; N,N-dimethylaminopropyl acrylamide methyl chloride quaternary; trimethyl-(vinyloxyethyl) ammonium chloride; 1-vinyl-2,3-dimethylimidazolinium chloride; vinyl benzyl amine hydrochloride; vinyl pyridinium hydrochloride; and mixtures thereof. Quaternary amine monomers which may be used in the composition of the invention can include those obtained from the above amine monomers such as by protonation using an acid or via an alkylation reaction using an alkyl halide. Alternatively, the ethylenically unsaturated monomer capable of providing a cationic charge comprises a quaternary derivative capable of providing hydrophobicity. In a preferred embodiment, the quaternary derivative is based on an alkyl group having two to twenty carbons (C2 to C20). For example, one could use: 1. CH2═C(R)COOCH(OH)CH2N+(X−)(R″) where R═H, CH3 and R═(CH2)nCH3 or (CF2)CF3 and X═Cl, Br, I or a sulfate. For example, this could be a reaction product of glycidyl methacrylate and a secondary amine which has then been quaternized 2. CH2═C(R)ΦCH2N+(X−)(R′) where R, R′ and X have the same significance as above. This is a similar reaction as compared to the one above with vinyl benzyl chloride as the starting material. 3. The third approach could be to start with vinyl pyridine and make the alkyl pyridinium salts as above. Amine salts can also be used and are obtained, for example, by the reaction of an epoxy group with a secondary amine and subsequent neutralization of the newly formed tertiary amine with an acid. An example of this is the reaction product of glycidyl methacrylate with a secondary amine that can be free radically polymerized. Quaternary amine functionality can also be generated as a post reaction on a preformed polymer having, for example, an epoxy group. Examples of these kinds of reactions are described in the article, “Polymer Compositions for Cationic Electrodepositable Coatings, Journal of Coatings Technology, Vol 54, No 686, March 1982. It should also be appreciated that cationic functionality can also be imparted via sulfonium or phosphonium chemistry, examples of which are also described in the above article. The composition preferably comprises from about 0.5 to about 75 percent of the ethylenically unsaturated monomer capable of providing a cationic charge based on the total monomer weight, the amount depending on the selected application of the polymer composition. The composition also comprises a component which is incorporated into the cationically-charged polymer composition to sterically stabilize the composition. Suitable components include, but are not limited to, monomers, polymers, and mixtures thereof as set forth below. For the purposes of the invention, the term “incorporated” with respect to the use of the monomer can be interpreted to mean that the monomer attaches to the backbone of the cationic polymer. The polymer which is “incorporated” into the composition can be interpreted to mean that it is adsorbed or grafted onto the composition surface, an example of which may be polyvinyl alcohol. This stabilizing component may encompass a nonionic monomer or polymer which incorporates steric stabilization to the composition particle without adversely affecting the polymer composition. Exemplary monomers that can be used as steric stabilizers include, but are not limited to, those which contain alkoxylated (e.g., ethoxylated or propoxylated) functionality. Examples of such monomers include those described by the formulas: CH2═C(R)COO(CH2CHR′O)nR″—where R═H, C1-C4 alkyl; and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, and n=1-30; or CH2═C(R)COO(CH2CH2O)n(CH2CHR′O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl, and R″═H, C1-C12 alkyl, n and m each may range from 1-15; and CH2═C(R)COO(CH2CHR′O)n(CH2CH2O)mR″—where R═H, C1-C4 alkyl, and R′═H, C1-C4 alkyl and R″═H, C1-C12 alkyl, n and m=1-15. Preferred compounds are undecylenic acid esters where R″ is C11. Preferably, the monomers have a molecular weight of less than 2000. Ethoxylated mono- and diesters of diacids such as maleic and itaconic acids can also be used to achieve the same stabilizing effect. Polymerizable surfactants based on acrylate, methacrylate, vinyl and allyl versions of surfactants can also be used. An example of this is TREM LF-40 sold by Henkel of Düsseldorf, Germany. These surfactants possess ethylenic unsaturation that allows the surfactants to be incorporated into the polymer composition. Similar to other surfactants, these materials have hydrophobic and hydrophilic functionality that varies. Surfactants that are particularly applicable to the present invention are nonionic surfactants wherein the hydrophilic character is believed to be attributable to the presence of alkylene oxide groups (e.g., ethylene oxide, propylene oxide, butylene oxide, and the like). Block copolymers of ethylene oxide and/or propylene oxide such as the Pluronic or Tetronic series from BASF can also be used, particularly in antistatic applications. The degree of hydrophilicity can vary based on the selection of functionality. Polymers can also be used to provide steric stability. For example, protective colloids may be used. Examples of these materials include, but are not limited to, polyvinyl alcohols, polyvinyl pyrollidone, hydroxyethyl cellulose, polyethylene glycols, polyglycol-ethers, propylene glycols, ethylene oxide/propylene oxide copolymers, ethylene oxide/propylene oxide copolymers and/or ethylene oxide/butylene oxide copolymers and the like. Mixtures of any of the above monomers and polymers may also be used. Other monomers and polymers which may be used to impart stability are listed in U.S. Pat. No. 5,830,934 to Krishnan et al. The steric stabilization component which is used to stabilize the composition is present in an amount ranging from about 0.5 to about 75 percent based on the total weight of the monomers. The composition of the invention also may include a free radical initiator, the selection of which is known in the art. Preferably, a free radical initiator is used which generates a cationic species upon decomposition and contributes to the cationic charge of the composition. An example of such an initiator is 2,2′-azobis(2-amidinopropane) dihydrochloride) sold commercially as Wako V-50 by Wako Chemicals of Richmond, Va. The composition of the invention may also include other additives to improve the physical and/or mechanical properties of the polymer, the selection of which are known to one skilled in the art. These additives include processing aids and performance aids such as, but are not limited to, crosslinking agents, natural and synthetic binders, plasticizers, softeners, foam-inhibiting agents, froth aids, flame retardants, dispersing agents, pH-adjusting components, sequestering or chelating agents, and other components. In a preferred embodiment 0.1 to 1.0 weight percent of a nonionic surfactant can be used. Additionally, the composition preferably is devoid of conventional non-polymerizable cationic and anionic surfactants. The composition may be applied to the substrate as a coating or film using techniques known to those skilled in the art such as spraying, roll-coating, brushing, dipping, impregnation, size press and the like. The composition of the present invention can be blended with a base polymer including other polymers. Suitable polymers include various thermoplastic and thermosetting polymers including, but not limited to polyurethanes, phenolics, polyesters, polyolefins, polyamides, polycarbonates, polyethers, polyether-amides and imides, polyorganosilanes, polysulfones, polyisoprene, polychloroprene, acrylics, styrene-butadienes, styrene acrylonitriles, ABS, EVA, polytetrafluoroethylene, polyether-esters, polyepoxides, heterocyclic polymers such as polypyrrole, polyaniline, polythiophene and its derivatives and the like and latex-based materials. In another embodiment, the cationically-charged polymer can be blended with another polymer having antimicrobial or antistatic properties such as other cationic polymers. The blends could be made in situ creating an interpenetrating polymer network (IPN). Core shell latices or composites could be made that have one or more of these above mentioned components as a core on which subsequent polymerization could take place by an emulsion or suspension process. Another example of this would be making the polymers, e.g., urethanes, starting from the base raw materials by a suspension or dispersion/miniemulsion process followed by a radical process. Thus one could combine a condensation and a free radical process together. The objective would be to make a broader range of polymers that are hybrids. Another enhancement of the chemistry could come from using controlled radical polymerization processes such as RAFT, ATRP, and SFRP (with nitroxides) which would then provide polymers that would have a variety of architectures such as block, graft, stars, hyperbranched and dendrimers. This allows control of the morphology, activity, and uniqueness of the polymers and enables one to create molecules tailored to meet specific functions. The composition can be used in the form of an open or closed cell foam by adding surfactants and foaming agents. The foam can be used in a wide variety of ways so as to impart antimicrobial and/or antistatic properties to various articles. For example, a foam could be used to provide both sound deadening properties and antimicrobial/antistatic properties to an article like the foam underlay of a carpet. The foam could be used as the article itself, for example, the foam of a pillow or mattress. The foam could be used as an absorbent in a diaper thereby absorbing the urine while providing antimicrobial protection. Amphoteric or zwitterionic polymers in which an anionic polymer would be included could also be made using the composition of the present invention. Antimicrobial and/or antistatic agents may be used as an additive to enhance the inherent antimicrobial or antistatic nature of the compositions of the present invention. A potential antimicrobial monomer is undecylenic acid or alcohol or reaction products of undecylenic acid or alcohol with hydroxyl or acid containing materials having ethylenic unsaturation to produce an ester. An example of the acid functional monomer is acrylic acid or maleic anhydride. An example of the hydroxyl functional monomer is hydroxylethyl methacrylate or polyethylene glycol methacrylate. Undecylenic acid is known to provide antifungal properties and this could potentially offer advantages again in expanding the chemistry especially if combined with the cationic and phenolic type intermediates. Chitosan, modified chitosans or chitosan salts can also be incorporated into the composition. Chitosan is a naturally occurring amino functional saccharide which is known to be antimicrobial. Moreover, chitosan could also serve the dual purpose of also providing steric stabilization. Other antimicrobial agents include metal biocides such as silver, zinc, etc. and salts and oxides thereof, chlorhexidine, chlorhexidine gluconate, glutaral, halazone, hexachlorophene, nitrofurazone, nitromersol, povidone-iodine, thimerosol, C1-C5-parabens, hypochlorite salts, clofucarban, clorophene, poloxamer-iodine, phenolics, mafenide acetate, aminacrine hydrochloride, quaternary ammonium salts, oxychlorosene, metabromsalan, merbromin, dibromsalan, glyceryl laurate, sodium and/or zinc pyrithione, (dodecyl) (diethylenediamine) glycine and/or (dodecyl) (aminopropyl) glycine; phenolic compounds (e.g., phenols, m-cresol, n-cresol, p-cresol, o-phenyl-phenol, resorcinol, vinyl phenol, etc.), polymeric guanidines, quaternary ammonium salts, polymyxins, bacitracin, circulin, the octapeptins, lysozmye, lysostaphin, cellulytic enzymes generally, vancomycin, ristocetin, the actinoidins and avoparcins, tyrocidin A, gramicidin S, polyoxin D, tunicamycin, neomycin, streptomycin and the like. It is not feasible to give here an exhaustive list of potentially useful antimicrobials, but this may be found in compendia such as, “Antibiotics, Chemotherapeutics, and Antibacterial Agents for Disease Control,” M. Grayson, Ed., J. Wiley and Sons, N.Y., 1982. Classification of antibiotics by their mode of action may be found in “The Molecular Basis of antibiotic Action,” Second Edition, E. F. Gale et al., J. Wiley and sons, N.Y., 1981. Other additives and polymer systems are described in U.S. Pat. No. 3,872,128 to Byck, U.S. Pat. No. 5,024,840 to Blakely et al, U.S. Pat. No. 5,290,894 to Malrose et al, U.S. Pat. Nos. 5,967,714, 6,203,856 and 6,248,811 to Ottersbach et al, U.S. Pat. No. 6,194,530 to Klasse et al. and U.S. Pat. No. 6,242,526 to Siddiqui et al., the disclosures of which are incorporated by reference in their entirety. Antistatic agents include nitrogen compounds such as long chain amines, amides and quaternary ammonium salts, esters of fatty acids and their derivatives, polyhydric alcohols and their derivatives, phosphoric acid derivatives, solutions of electrolytes in liquids with high dielectric constants, metallic salts and oxides, metals (e.g., iron), carbon black, carbon nanotubes and semiconductors. Specific examples include Hostenstat® and Sandin® antistats from Clariant, Larostat® antistats from BASF, Bayhydrol® antistats from Bayer, Atmer® antistats from Uniquema, VersaTL® from Alco, and various other antistats offered by Atofina, Noveon, Ciba, Eastman, Agfa, Ormecon Chemie and Panipol. With respect to providing antistatic compositions, the reaction products of alkyl amines or ethoxylated amines with maleic anhydride could also be used. This could lead to a maleimide-type monomer with ethoxylate or alkyl chains that could be copolymerized with other monomers. Copolymers of alkylene oxide macromers and other monomers such as styrene sulfonates, acrylamidopropane sulfonic acid (AMPS) carboxylic acids, (e.g., acrylic or methacrylic derivatives) are potential antistatic additives. Other antistatic solutions are suggested in U.S. Pat. Nos. 4,029,694 and 4,093,676 to Weipert et al, U.S. Pat. No. 4,098,842 to Login, U.S. Pat. No. 4,857,590 to Gaggar et al. and U.S. Pat. No. 4,859,727 to Sasaki et al., the disclosures of which are incorporated by reference in their entirety. The cationically-charged polymer composition could also be used as an additive in the solid form to be added to specific substrates and then processed. In the case where the solid is to be used it would be added to the base polymer during the processing stage, e.g., as pellets into polycarbonate or SAN before extrusion or injection molding. In this case, the composition of our invention would become the integral part of the article as opposed to a topical coating on the surface. The polymers can be made in the solid form either by spray drying a dispersion/emulsion or by making it directly as a solid by suspension polymerization. It is possible to conceive ways by which the composition of our invention can be directly incorporated into a fiber while it is being processed. One way is during the melt spinning/extrusion of the fibers. The additive could be added directly to the polymer used for fiber making e.g., polyolefins, polyester, acrylic etc during the processing stage or could be pre-compounded into a master batch with the polymer and other ingredients and mixed thoroughly before addition to the fiber making polymer. This way the composition is mixed thoroughly before addition to the fiber making polymer. This way the composition would be directly extruded or be part of the fiber and impart its antimicrobial or antistatic properties. This would apply to any polymer that can be melt spun and the additive can be designed to impart compatibility, hydrophilicity, flexibility etc to the fiber in addition to the stated properties for which it was designed. These fibers then could be used for many applications some of which have been outlined above. Solution spinning of fibers could also be considered in which case the additive would be dissolved in the fiber spinning solution and then extruded through spinnerets. Another area which would benefit from the solid additive processing is plastics and rubber articles. Here again one could conceive of adding the composition polymer (which would serve as a thermoplastic additive) as powder or pellets directly during the processing step such as extrusion, injection molding etc or could be pelletized prior to actually processing in a compatibilizing polymer such as EVA and EMA using the extruder and added to any thermoplastic polymer in specific amounts during a post processing step using the extruder, injection molding machine, blow molding, etc. Typical plastic processing steps for thermoplastic polymers would be compatible with these solid additives. Also, the additive can be mixed along with other ingredients such as pigments, flow aids, lubricants etc, and the desired polymer to make what are known as master batches. These master batches would typically be made in high shear mixing equipment such as a Banbury mixer and the mix would then be pelletized in an extruder. The master batches would then be processed by the manufacturer of plastic articles or films using conventional plastic processing equipment. Any or all of the above methods could be used to deliver the additive into a matrix polymer for providing the desired antimicrobial and/or antistatic property. Once again the applications would be similar to the ones outlined above. The dry polymer could be added to thermoset polymer also e.g. phenolics, epoxies etc and processed using techniques such as compression molding etc. the additive processing techniques for rubber would be similar in terms of making a rubber compound using a Banbury and then made into sheets, for example through a two roll mill or extruded into tubes, pipes, hoses etc. One specific application could be in the area of artificial or synthetic marble surfaces made of acrylic polymers e.g., Corian® or unsaturated polyesters. The polymer additive could be compounded into these resins and then cast or cured to incorporate it into the matrix. This would permanently incorporate the additive into the matrix instead of a topical coating. The same could be for the use of these additives in gel coats and casting resins used in boats etc to provide surfaces with the described properties. If an unsaturated polyester resin were used, it would be preferable to dissolve the additive in styrene Another example for solids would be use of these as additives in hot melt adhesive compositions to create adhesives that have the described attributes. The polymer would have to have the required compatibility and molecular weight to provide adequate flow. In the case of cellulosic materials, the use of solid materials can be envisaged in composites made from wood where the wood in granular, pelletized or powder form could be compounded with other ingredients and then molded into a shape by techniques such as compression molding. Thermosetting resins such as UF, MF, epoxy and urethane resins are used for bonding wood and the polymer composition could be added along with these during the processing stage. Applications such as decking and construction materials and OSB boards could be considered using this approach. The use of solid material in paper can be considered in the making of high-pressure laminate or decorative laminates and molded articles. Once again the solid material can be combined with pulp fibers and fillers and compression molded to make the finished product. Packaging materials such as cartons, boxes, etc could also benefit from the practice of the present invention. The cationically-charged polymer composition in dry form can be combined with cement/concrete and set to form a concrete structure that has the desired addendum properties. Grouts, sealers, mastics etc would also be amenable to the use of powders. This can also be combined with other fillers etc to make granite counter tops, floors etc that have antimicrobial-antistatic properties. Redispersible powders in cement would be another use and in decorative concrete. The composition of the present invention should also be used in combination with other methods and formulations for improving antimicrobial and/or antistatic properties such as described in U.S. Pat. No. 3,872,128 to Byck, 5,024,840 to Blakely et al, U.S. Pat. No. 5,290,894 to Malrose et al, U.S. Pat. Nos. 5,967,714, 6,203,856 and 6,248,811 to Ottersbach et al, U.S. Pat. No. 6,194,530 to Klasse et al., U.S. Pat. No. 6,242,526 to Siddiqui et al., U.S. Pat. Nos. 4,029,694 and 4,093,676 to Weipert et al, U.S. Pat. No. 4,098,842 to Login, U.S. Pat. No. 4,857,590 to Gaggar et al., and U.S. Pat. No. 4,859,727 to Sasaki et al. Potential Uses The composition of the present invention can be applied to a wide variety of substrates using various techniques known to those skilled in the art. The following list is not to be intended as limiting the types of substrates. For example, the composition as a latex can be applied as a coating or as a film to the following substrates: 1. Nonwoven and Woven Textiles and Fibers: Examples would include natural fibers such as cotton and wool to synthetic fibers such as nylon, acrylics, polyesters, urethanes etc. Application process would be through processes such as rod/knife coating, impregnation, back coatings, printing or as pretreatments on individual fibers or as a finished good. 2. Plastics/Rubber: Examples would include commodity molded thermoplastics like polyolefins to engineering thermoplastics such as polysulfones, acetals, polycarbonates etc., thermosets like epoxies, urethanes etc and as extruded or blown films. The polymer would be applied as a coating on the surface by rod/knife coating, spray, dipping or as a laminate coating during the extrusion process or as a coating applied in the mold during the molding process. Rubber products would include sheets, extruded/molded articles, composites etc. 3. Paper: This would include both preformed paper and as additives in the wet end process. Typical paper processes would include impregnation or saturation, rod/knife coating etc, size press, and wet end addition, spray-on. 4. Inorganic/Organic Materials: This would cover a wide range of delivery mechanisms based on encapsulation and coating of inorganic particles e.g., clay, mica, pigments, biocides, pesticides, etc., and also as part of a formulation involving a variety of fillers to make a finished product e.g., gypsum board, sealer, grout etc., or as a coating on an inorganic surface such as a drywall, tiles, applied by spraying, roller coating, brushing etc. This would also cover its use in glass fiber mat coating or impregnation. 5. Wood: This would include all kinds of wood substrates both natural and engineered and the application process could be a variety of methods as outlined above. 6. Metal: Again this would encompass both metals and metal alloys, e.g., carbon steel, stainless steel and including solid steel bars, sheets, coils, ropes etc wherein the composition is applied as a coating by one of the numerous processes such as spraying dipping, brushing, roller coating etc. Specific applications include textiles such as: residential and commercial carpets, tiles, etc.; liquid and air filters—HVAC, vacuum cleaners, automotive; medical surgical gowns, drapes, dressings, covers etc.; pretreatment for fibers, printed and dyed fabrics for apparel, furnishings, sheets, towels etc.; diapers and incontinence articles, interior automotive applications such as trim, upholstery, mats, filters, etc.; upholstery coatings, laminating and bonding adhesives; foams for sound absorbency; foamed articles such as pillows and mattresses; belting—food handling etc.; tapes—masking tapes, surgical, industrial tapes e.g., electrical, industrial and household cleaning wipes, cloths and sponges; shoe products e.g., insoles, box toes, etc.; plastics/rubber such as tool handles—e.g., screw drivers, shovels, etc.; toys, rubber gloves, sheets, articles; machinery housing—e.g., computers, display and diagnostic devices, vacuum cleaners, instrumentation; medical devices—e.g., catheters, balloons, tubing, syringes, diagnostic kits etc.; packaging/product protection—perishables, computer peripherals, semiconductors, memory chips, CD's, DVD's etc.; impact modifiers for acrylics, polycarbonates etc.; overdips and underdips for gloves—gloves for clean room, breathable films, antipenetrant for fabric supported gloves; cutting boards; extruded and blown films for packaging; paper: vacuum bags, book covers, air filters, liquid filters, wallcoverings, wet and dry wipes, tissues, etc.; felt for vinyl floor coverings, molded pulp applications, packaging—boxes, cartons, molded articles etc.; size press coatings—gift wraps, ink jet media, breathable coatings, etc.; wet end additives in paper, tapes and labels—masking, surgical, general purpose etc.; adhesives—tapes, labels, decals, films, book binding, pressure sensitive and FPLA, etc.; shoe insoles, inorganic/organic materials such as coating/encapsulation of fillers and pigments, construction sealers and grouts, gypsum wallboard coatings/paints, exterior/interior coatings; tile adhesives, floor coatings—hospitals, clean rooms, clinics, schools etc.; coatings for hospital and medical environments; ceiling tiles, glass fiber coating—glass mats, insulation, reinforced composites etc.; liquid disinfectants and cleaners, personal care—shampoos, lotions, creams, hair and skin care, body wash, cosmetics etc.; hygiene coatings of surfaces other than floors—hospitals, clinics, schools, homes and offices, hard and porous surface coatings—walls, ceilings, floors, counter tops etc.; decorative concrete, wood such as oriented strand board (OSB) coatings, decking and construction materials—coating, impregnation etc.; composite construction materials, furniture coatings; hygiene coatings—table and counter tops, door knobs, door handles etc.; flooring—laminates, hardwood and other composite floors, decorative laminates—table tops, counter tops, furniture etc.; metal such as cabinets, door knobs, handles etc.; furniture, coatings—appliances, OEM etc. Having generally described the present invention, a further understanding can be obtained by reference to the examples provided herein for purposes of illustration only and are not intended to be limiting. EXAMPLES Examples 1-4 were tested for antimicrobial properties using Bacillus subtilis ATCC #6633 as the test organism. Example 3 is an anionic polymer and is a comparative example. 1 2 3 4 Monomer Composition Styrene 54.5 47.5 55 39.5 Butyl acrylate 13.5 13.5 0 28.5 Butadiene 20.0 20.0 43 0 Lauryl Methacrylate 0 0 0 10.0 N-methylolacrylamide 2.0 2.0 0 2.0 Dimethyl aminoethyl 5.0 12.0 0 15.0 methacrylate methyl chloride quaternary Monomethyl maleate 2.0 0 Surfactants Abex 2525 0.5 0.5 0.0 0.5 Methoxyl polyethylene 5.0 5.0 0.0 5.0 glycol methacrylate Dowfax 2A1 1.2 Quanticult® Plus cultures containing 10-100 CFU/0.1 mL were inoculated and allowed to dry onto fifteen coupons for each test coating. Fifteen coupons coated with the negative control coating were inoculated in the same manner. Recovery for each surface type was determined after one hour, four hours and 24 hours, using Rodac plates (TSA containing Tween and Lecithin). At each sample time a Rodac plate was touched to five coupons for each surface type and incubated at 30-35° C. for 48 hrs-5 days. The CFU were counted and averaged for each surface type. The test surface results were compared with the negative control surface results. Recovery <70% indicates that the material is antimicrobial. The results are provided in Tables 1-4. TABLE 1 (Example 1) Microbial Recovery 1 Hour 4 Hour 24 Hour B. subtilis Other B. subtilis Other Other Replicate CFU CFU CFU CFU B. subtilis CFU CFU 1 0 2 0 4 0 6 2 0 9 0 9 0 4 3 0 20 0 2 0 9 4 0 24 0 7 0 7 5 0 31 0 6 0 3 Average 0 N/A 0 N/A 0 N/A % Recovery1,2 N/A 0 0 0 1Percent Recovery calculated using only the B. subtilis CFUs. 2Percent Recovery calculated by comparing the average CFU to those of Example 3. TABLE 2 (Example 2) 1 Hour 4 Hour 24 Hour B. subtilis Other B. subtilis Other Other Replicate CFU CFU CFU CFU B. subtilis CFU CFU 1 0 0 0 1 0 1 2 0 0 0 1 0 3 3 0 0 0 2 0 4 4 0 0 0 0 0 5 5 0 1 0 0 0 3 Average 0 N/A 0 N/A 0 N/A % Recovery1,2 N/A 0 0 0 1Percent Recovery calculated using only the B. subtilis CFUs. 2Percent Recovery calculated by comparing the average CFU to those of Example 3. TABLE 3 (Comparative Example 3) 1 Hour 4 Hour 24 Hour B. subtilis Other B. subtilis Other Other Replicate CFU CFU CFU CFU B. subtilis CFU CFU 1 1 4 7 12 4 13 2 3 5 6 2 0 10 3 2 2 5 5 0 9 4 2 3 1 8 0 15 5 2 2 9 11 2 6 Average 2 N/A 5.6 N/A 1.2 N/A 1% Recovery calculated using only the B. subtilis CFUs. TABLE 4 (Example 4) 1 Hour 4 Hour 24 Hour B. subtilis Other B. subtilis Other Other Replicate CFU CFU CFU CFU B. subtilis CFU CFU 1 0 0 0 2 0 0 2 0 0 0 0 0 2 3 0 0 1 1 0 1 4 1 0 0 0 0 1 5 0 0 0 0 0 3 Average 0.2 N/A 0.2 N/A 0 N/A % Recovery1,2 N/A 10 10 0 1Percent Recovery calculated using only the B. subtilis CFUs. 2Percent Recovery calculated by comparing the average CFU to those of Example 3. This demonstrates that the compositions of the present invention provide rapid kill of bacteria and also are effective as a broad spectrum antimicrobial polymer composition as compared to comparative example, Example 3. The compositions of Examples 1, 2 and 4 were coated onto paper. The average charge decay time was determined by measuring the length of time for charge to decay to 10 percent of its value when the object is grounded. In operation, the object is charged using a dc voltage service and the drop in voltage is measured after grounding. The surface resistivity is measured by placing two electrodes on the surface and applying a fixed voltage to one electrode. The current that traveled across the surface to the other electrode is measured. Resistance then can be measured from the current and applied voltage. The results are provided in Table 5. TABLE 5 (Antistatic Properties-Coated Free Sheet) Uncoated Paper Example 1 Example 2 Example 4 Polymer — 5.0 10.0 5.0 10.0 5.0 10.0 add-on (lbs/3000 sq ft) Relative 12 55 12 55 12 55 12 55 12 55 12 55 12 55 Humidity (%) Avg. 54.8 0.17 8.9 0.02 8.0 0.04 0.87 0.01 0.02 0.01 0.01 0.01 0.01 0.01 Charge Decay Time(s) Surface >E12 3.4E+ >E12 2.5E+ >E12 2.1+ 2.2E+ 3.8E+ 6.6E+10 1.0E+08 9.0E+10 1.3E+08 1.1E+10 3.1E+07 Resistivity 11 11 11 12 09 (ohms/sq. @ 10 V) This illustrates that antistatic properties are imparted by the composition of the present invention. In the specification, there have been disclosed typical embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. The following claims are provided to ensure that the present application meets all statutory requirements as a priority application in all jurisdictions and shall not be construed as setting forth the full scope of the present invention.
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<SOH> FIELD AND BACKGROUND OF THE INVENTION <EOH>The present invention relates to polymers having inherent antimicrobial or antistatic properties. Such polymers can be applied or used in conjunction with a wide variety of substrates (e.g., textiles, metal, cellulosic materials, plastics, etc.) to provide the substrate with antimicrobial and/or antistatic properties. In addition, the polymers can also be combined with other polymers (e.g., the polymers of the invention can be used as additives) to provide such other polymers with antimicrobial and/or antistatic properties. Various bacteria, fungi, viruses, algae and other microorganisms are known to be in the environment and to potentially adversely affect people coming in contact with them. Such microorganisms are often undesirable as a cause of illness, odors and damage to a wide variety of material and substrates. In order to combat such microorganisms, antimicrobial agents have been suggested. However, there is also a need for such agents to be both sustainable and to be compatible, and to be used on and with a wide variety of polymer materials and substrates. Various additives and polymer systems have been suggested as providing antimicrobial properties. See, for example, U.S. Pat. No. 3,872,128 to Byck, U.S. Pat. No. 5,024,840 to Blakely et al, U.S. Pat. No. 5,290,894 to Malrose et al, U.S. Pat. No. 5,967,714, 6,203,856 and U.S. Pat. No. 6,248,811 to Ottersbach et al, U.S. Pat. No. 6,194,530 to Klasse et al. and U.S. Pat. No. 6,242,526 to Siddiqui et al. With respect to antistatic properties, various substrates tend to accumulate static electrical charge due to low electrical conductivity. This is particularly problematic with plastic substrates. Such accumulation can adversely affect processing, cause electrical damage (e.g., in semiconductor devices), provide a fire hazard through the formation of an electrical arc, and exposes personnel handling the substrate to electrical shock. Various solutions to such static buildup have been suggested. See, for example, U.S. Pat. No. 4,029,694 and U.S. Pat. No. 4,093,676 to Weipert et al, U.S. Pat. No. 4,098,842 to Login, U.S. Pat. No. 4,857,590 to Gaggar et al. and U.S. Pat. No. 4,859,727 to Sasaki et al. There, however, remains a need for potentially less toxic polymer compositions that provide sustainable antimicrobial and/or antistatic properties to a wide variety of substrates and materials.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention relates to a substrate having antimicrobial and/or antistatic properties. Such properties are imparted by applying a coating or film formed from a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated monomer capable of providing a cationic charge to the polymer composition, and a steric stabilization component incorporated into the cationically-charged polymer composition. The present invention also relates to a polymeric material comprising a base polymer blended with a cationically-charged polymer composition comprising a noncationic ethylenically unsaturated monomer, an ethylenically unsaturated cationic monomer capable of providing a cationic charge to the polymer composition, and a steric stabilization component incorporated into the cationically-charged polymer composition. The present invention also relates to a method of providing antimicrobial and/or antistatic properties to a substrate. The method includes the step of applying the cationically-charged polymer composition described above to a substrate. The present invention also relates to a method of imparting antimicrobial and/or antistatic properties to a polymer material. The method includes the step of blending a base polymer with the cationically-charged polymer composition described above. detailed-description description="Detailed Description" end="lead"?
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20040701
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20090217
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20050106
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75327.0
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CAIN, EDWARD J
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ANTIMICROBIAL AND ANTISTATIC POLYMERS AND METHODS OF USING SUCH POLYMERS ON VARIOUS SUBSTRATES
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SMALL
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ACCEPTED
| 2,004
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10,882,588
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ACCEPTED
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Multiple-path remediation
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A security information management system is described, wherein a database of potential vulnerabilities is maintained, along with data describing remediation techniques (patches, policy settings, and configuration options) available to protect against them. At least one vulnerability is associated in the database with multiple available remediation techniques. In one embodiment, the system presents a user with the list of remediation techniques available to protect against a known vulnerability, accepts the user's selection from the list, and executes the selected technique. In other embodiments, the system uses a predetermined prioritization schedule to automatically select among the available remediation techniques, then automatically executes the selected technique.
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1. A system, comprising: a database associating a plurality of device vulnerabilities to which computing devices can be subject, each having a vulnerability identifier, with a plurality of remediation techniques that remediate the plurality of device vulnerabilities; such that each of the device vulnerabilities is associated with at least one remediation technique; the remediation techniques are each selected from the type group consisting of patches, policy settings, and configuration options; and a first one of the device vulnerabilities is associated with at least two remediation techniques; a query signal comprising the vulnerability identifier for the first one of the device vulnerabilities; and a response signal, automatically generated in response to the query signal, that describes the at least two remediation techniques. 2. The system of claim 1, further comprising a user interface that: offers the at least two remediation techniques for selection by a user; accepts a selection by the user of one of the at least two remediation techniques; and implements the selected one of the at least two remediation techniques. 3. The system of claim 1, further comprising: a processor; and a memory encoded with programming instructions executable by the processor to: receive the response signal; automatically select one from the at least two remediation techniques based on the type of each of the at least two remediation techniques; and apply the selected remediation technique.
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CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 60/484,085. This application is also related to applications titled REAL-TIME VULNERABILITY MONITORING (Attorney Docket No. 36029-3), POLICY-PROTECTION PROXY (Attorney Docket No. 36029-5), VULNERABILITY AND REMEDIATION DATABASE (Attorney Docket No. 36029-6), AUTOMATED STAGED PATCH AND POLICY MANAGEMENT (Attorney Docket No. 36029-7), and CLIENT CAPTURE OF VULNERABILITY DATA (Attorney Docket 36029-8), all filed on even date herewith. All of these applications are hereby incorporated herein by reference as if fully set forth. FIELD OF THE INVENTION The present invention relates to computer systems, and more particularly to management of security of computing and network devices that are connected to other such devices. BACKGROUND With the growing popularity of the Internet and the increasing reliance by individuals and businesses on networked computers, network security management has become a critical function for many people. Furthermore, with computing systems themselves becoming more complex, security vulnerabilities in a product are often discovered long after the product is released into general distribution. Improved methods are needed, therefore, for managing updates and patches to software systems, and for managing configurations of those systems. The security management problem is still more complex, though. Often techniques intended to remediate vulnerabilities (such as configuration changes, changes to policy settings, or application of patches) add additional problems. Sometimes patches to an operating system or application interfere with operation of other applications, and can inadvertently disable mission-critical services and applications of an enterprise. At other times, remediation steps open other vulnerabilities in software. There is, therefore, a need for improved security management techniques. SUMMARY One form of the present invention is a database of information about a plurality of devices, updated in real-time and used by an application to make a security-related decision. The database stores data indicating the installed operating system(s), installed software, patches that have been applied, system policies that are in place, and configuration information for each device. The database answers queries by one or more devices or applications attached by a network to facilitate security-related decision making. In one form of this embodiment, a firewall or router handles a connection request or maintenance of a connection based on the configuration information stored in the database that relates to one or both of the devices involved in the transmission. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a networked system of computers in one embodiment of the present invention. FIG. 2 is a block diagram showing components of several computing devices in the system of FIG. 1. FIGS. 3 and 4 trace signals that travel through the system of FIGS. 1 and 2 and the present invention is applied to them. DESCRIPTION For the purpose of promoting an understanding of the principles of the present invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will, nevertheless, be understood that no limitation of the scope of the invention is thereby intended; any alterations and further modifications of the described or illustrated embodiments, and any further applications of the principles of the invention as illustrated therein are contemplated as would normally occur to one skilled in the art to which the invention relates. Generally, the present invention in its preferred embodiment operates in the context of a network as shown in FIG. 1. System 100 includes a vulnerability and remediation database 110 connected by Internet 120 to subnet 130. In this exemplary embodiment, firewall 131 serves as the gateway between Internet 120 and the rest of subnet 130. Router 133 directs connections between computers 137 and each other and other devices on Internet 120. Server 135 collects certain information and provides certain data services that will be discussed in further detail herein. In particular, security server 135 includes processor 142, and memory 144 encoded with programming instructions executable by processor 142 to perform several important security-related functions. For example, security server 135 collects data from devices 131, 133, 137, and 139, including the software installed on those devices, their configuration and policy settings, and patches that have been installed. Security server 135 also obtains from vulnerability and remediation database 110 a regularly updated list of security vulnerabilities in software for a wide variety of operating systems, and even in the operating systems themselves. Security server 135 also downloads a regularly updated list of remediation techniques that can be applied to protect a device from damage due to those vulnerabilities. In a preferred embodiment, each vulnerability in remediation database 110 is identified by a vulnerability identifier, and the vulnerability identifier can be used to retrieve remediation information from database 110 (and from database 146, discussed below in relation to FIG. 2). In this preferred embodiment, computers 137 and 139 each comprise a processor 152, 162, memory 154, 164, and storage 156, 166. Computer 137 executes a client-side program (stored in storage 156, loaded into memory 154, and executed by processor 152) that maintains an up-to-date collection of information regarding the operating system, service pack (if applicable), software, and patches installed on computer 137, and the policies and configuration data (including configuration files, and elements that may be contained in files, such as *.ini and *.conf files and registry information, for example), and communicates that information on a substantially real-time basis to security server 135. In an alternative embodiment, the collection of information is not retained on computer 137, but is only communicated once to security server 135, then is updated in real time as changes to that collection occur. In these exemplary systems, “configuration information” for each device may take the form of initialization files (often named *.ini or *.conf), configuration registry (such as the Windows Registry on Microsoft WINDOWS operating systems), or configuration data held in volatile or non-volatile memory. Such configuration information often determines what and how data is accepted from other devices, sent to other devices, processed, stored, or otherwise handled, and in many cases determines what routines and sub-routines are executed in a particular application or operating system. Computer 139 stores, loads, and executes a similar software program that communicates configuration information pertaining to computer 139 to security server 135, also substantially in real time. Changes to the configuration registry in computer 139 are monitored, and selected changes are communicated to security server 135 so that relevant information is always available. Security server 135 may connect directly to and request software installation status and configuration information from firewall 131 and router 133, for embodiments wherein firewall 131 and router 133 do not have a software program executing on them to communicate this information directly. This collection of information is made available at security server 135, and combined with the vulnerability and remediation data from source 110. The advanced functionality of system 100 is thereby enabled as discussed further herein. Turning to FIG. 2, one sees additional details and components of the devices in subnet 130. Computers 137 and 139 are traditional client or server machines, each having a processor 152, 162, memory 154, 164, and storage 156, 166. Firewall 131 and router 133 also have processors 172, 182 and storage 174, 184, respectively, as is known in the art. In this embodiment, devices 137 and 139 each execute a client-side program that continuously monitors the software installation and configuration status for that device. Changes to that status are communicated in substantially real time to security server 135, which continuously maintains the information in database 146. Security server 135 connects directly to firewall 131 and router 133 to obtain software installation and configuration status for those devices in the absence of a client-side program running thereon. Processors 142, 152, 162 may each be comprised of one or more components configured as a single unit. Alternatively, when of a multi-component form, processor 142, 152, 162 may each have one or more components located remotely relative to the others. One or more components of processor 142, 152, 162 may be of the electronic variety defining digital circuitry, analog circuitry, or both. In one embodiment, processor 142, 152, 162 are of a conventional, integrated circuit microprocessor arrangement, such as one or more PENTIUM 4 or XEON processors from INTEL Corporation of 2200 Mission College Boulevard, Santa Clara, Calif., 95052, USA, or ATHLON XP processors from Advanced Micro Devices, One AMD Place, Sunnyvale, Calif., 94088, USA. Memories 144, 154, 164 may include one or more types of solid-state electronic memory, magnetic memory, or optical memory, just to name a few. By way of non-limiting example, memory 40b may include solid-state electronic Random Access Memory (RAM), Sequentially Accessible Memory (SAM) (such as the First-In, First-Out (FIFO) variety or the Last-In First-Out (LIFO) variety), Programmable Read Only Memory (PROM), Electrically Programmable Read Only Memory (EPROM), or Electrically Erasable Programmable Read Only Memory (EEPROM); an optical disc memory (such as a DVD or CD ROM); a magnetically encoded hard drive, floppy disk, tape, or cartridge media; or a combination of any of these memory types. Also, memories 144, 154, 164 may be volatile, nonvolatile, or a hybrid combination of volatile and nonvolatile varieties. In this exemplary embodiment, storage 146, 156, 166 comprises one or more of the memory types just given for memories 144, 154, 164, preferably selected from the non-volatile types. This collection of information is used by system 100 in a wide variety of ways. With reference to FIG. 3, assume for example that a connection request 211 arrives at firewall 131 requesting that data be transferred to computer 137. The payload of request 211 is, in this example, a probe request for a worm that takes advantage of a particular security vulnerability in a certain computer operating system. Based on characteristics of the connection request 211, firewall 131 sends a query 213 to security server 135. Query 213 includes information that security server 135 uses to determine (1) the intended destination of connection request 211, and (2) some characterization of the payload of connection request 211, such as a vulnerability identifier. Security server 135 uses this information to determine whether connection request 211 is attempting to take advantage of a particular known vulnerability of destination machine 137, and uses information from database 146 (see FIG. 2) to determine whether the destination computer 137 has the vulnerable software installed, and whether the vulnerability has been patched on computer 137, or whether computer 137 has been configured so as to be invulnerable to a particular attack. Security server 135 sends result signal 217 back to firewall 131 with an indication of whether the connection request should be granted or rejected. If it is to be granted, firewall 131 passes the request to router 133 as request 219, and router 133 relays the request as request 221 to computer 137, as is understood in the art. If, on the other hand, signal 217 indicates that connection request 211 is to be rejected, firewall 133 drops or rejects the connection request 211 as is understood in the art. Analogous operation can protect computers within subnet 130 from compromised devices within subnet 130 as well. For example, FIG. 4 illustrates subnet 130 with computer 137 compromised. Under the control of a virus or worm, for example, computer 137 sends connection attempt 231 to router 133 in an attempt to probe or take advantage of a potential vulnerability in computer 139. On receiving connection request 231, router 133 sends relevant information about request 231 in a query 233 to security server 135. Similarly to the operation discussed above in relation to FIG. 3, security server 135 determines whether connection request 231 poses any threat, and in particular any threat to software on computer 139. If so, security server 135 determines whether the vulnerability has been patched, and if not, it determines whether computer 139 has been otherwise configured to avoid damage due to that vulnerability. Security server 135 replies with signal 235 to query 233 with that answer. Router 133 uses response 235 to determine whether to allow the connection attempt. In some embodiments, upon a determination by security server 135 that a connection attempt or other attack has occurred against a computer that is vulnerable (based on its current software, patch, policy, and configuration status), security server 135 selects one or more remediation techniques from database 146 that remediate the particular vulnerability. Based on a prioritization previously selected by an administrator or the system designer, the remediation technique(s) are applied (1) to the machine that was attacked, (2) to all devices subject to the same vulnerability (based on their real-time software, patch, policy, and configuration status), or (3) to all devices to which the selected remediation can be applied. In various embodiments, remediation techniques include the closing of open ports on the device; installation of a patch that is known to correct the vulnerability; changing the device's configuration; stopping, disabling, or removing services; setting or modifying policies; and the like. Furthermore, in various embodiments, events and actions are logged (preferably in a non-volatile medium) for later analysis and review by system administrators. In these embodiments, the log also stores information describing whether the target device was vulnerable to the attack. A real-time status database according to the present invention has many other applications as well. In some embodiments, the database 146 is made available to an administrative console running on security server 135 or other administrative terminal. When a vulnerability is newly discovered in software that exists in subnet 130, administrators can immediately see whether any devices in subnet 130 are vulnerable to it, and if so, which ones. If a means of remediation of the vulnerability is known, the remediation can be selectively applied to only those devices subject to the vulnerability. In some embodiments, the database 146 is integrated into another device, such as firewall 131 or router 133, or an individual device on the network. While some of these embodiments might avoid some failures due to network instability, they substantially increase the complexity of the device itself. For this reason, as well as the complexity of maintaining security database functions when integrated with other functions, the network-attached device embodiment described above in relation to FIGS. 1-4 is preferred. In a preferred embodiment, a software development kit (SDK) allows programmers to develop security applications that access the data collected in database 146. The applications developed with the SDK access information using a defined application programming interface (API) to retrieve vulnerability, remediation, and device status information available to the system. The applications then make security-related determinations and are enabled to take certain actions based on the available data. In the preferred embodiment, database 146 includes vulnerability and remediation information such that, for at least one vulnerability, multiple methods of remediating the vulnerability are specified. When the system has occasion to implement or offer remediation of a vulnerability, all known alternatives are presented that are relevant to the device or machine's particular configuration or setup. For example, when a vulnerability of a device is presented to an administrator, the administrator is given a choice among the plurality of remediation options to remediate the vulnerability. In some embodiments, the administrator can select a preferred type of remediation that will be applied if available and a fallback type. For example, an administrator may select application of a policy setting over installation of a software patch, so that the risk of disruption of critical business systems is minimized. In other embodiments, an administrator or other user is presented with a set of user interface elements that identify multiple options for remediating and identifying the vulnerability. The administrator or user select the method to be used, and that remediation is applied to the vulnerable device(s). All publications, prior applications, and other documents cited herein are hereby incorporated by reference in their entirety as if each had been individually incorporated by reference and fully set forth. While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that would occur to one skilled in the relevant art are desired to be protected.
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<SOH> BACKGROUND <EOH>With the growing popularity of the Internet and the increasing reliance by individuals and businesses on networked computers, network security management has become a critical function for many people. Furthermore, with computing systems themselves becoming more complex, security vulnerabilities in a product are often discovered long after the product is released into general distribution. Improved methods are needed, therefore, for managing updates and patches to software systems, and for managing configurations of those systems. The security management problem is still more complex, though. Often techniques intended to remediate vulnerabilities (such as configuration changes, changes to policy settings, or application of patches) add additional problems. Sometimes patches to an operating system or application interfere with operation of other applications, and can inadvertently disable mission-critical services and applications of an enterprise. At other times, remediation steps open other vulnerabilities in software. There is, therefore, a need for improved security management techniques.
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<SOH> SUMMARY <EOH>One form of the present invention is a database of information about a plurality of devices, updated in real-time and used by an application to make a security-related decision. The database stores data indicating the installed operating system(s), installed software, patches that have been applied, system policies that are in place, and configuration information for each device. The database answers queries by one or more devices or applications attached by a network to facilitate security-related decision making. In one form of this embodiment, a firewall or router handles a connection request or maintenance of a connection based on the configuration information stored in the database that relates to one or both of the devices involved in the transmission.
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20040701
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20120911
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20050224
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70959.0
| 3
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ZIA, SYED
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MULTIPLE-PATH REMEDIATION
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SMALL
| 0
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ACCEPTED
| 2,004
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10,882,718
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ACCEPTED
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Method and apparatus for content filtering
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A method for filtering content makes use of local filtering agents for end users, and a portal to a network of human reviewing resources. Local filtering agents request content classification for unclassified content. The portal routes requests from local agents to available human reviewing resources. A content classification is provided by the reviewing resources, and may be saved in association with a content identifier for future use. The method permits human review of content within a short period after review is requested. In an embodiment of the invention, a centrally-located switch is provided for controlling filtering levels at one or more user terminals.
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1. A method for content filtering, comprising: receiving a plurality of requests for review of various content items, each of the various content items comprising information for presenting to end users over a wide area network; routing each of the plurality of requests to at least one of a plurality of reviewing resources, wherein each of the reviewing resources comprises at least one network-connected terminal for presenting content to a human reviewer; associating each of the various content items with at least one classification provided by the plurality of reviewing resources after review of the respective content items by a human reviewer; and providing classifications from the plurality of reviewing resources to a plurality of local filtering agents, wherein the classifications are configured for determining whether associated ones of the various content items are to be presented to end users each having an associated access level. 2. The method of claim 1, further comprising recording the classifications in a database, wherein each of the classifications is associated with an identifier for a respective one of the content items. 3. The method of claim 1, wherein the providing step further comprises providing the classifications for use in filtering content at anonymous client terminals. 4. The method of claim 1, wherein the receiving step further comprises receiving the plurality of requests originating from anonymous requests for content. 5. The method of claim 1, further comprising processing the plurality of requests so as to prevent a portion of the various content items from being reviewed by any human reviewer using the plurality of reviewing resources. 6. The method of claim 1, further comprising processing the plurality of requests so as to prevent personal identifying information from being presented to an human reviewer using the plurality of reviewing resources. 7. The method of claim 1, further comprising presenting a plurality of content items for simultaneous display on a terminal of at least one of the plurality of reviewing resources. 8. The method of claim 7, wherein the presenting step further comprises presenting the plurality of content items as thumbnail images. 9. The method of claim 1, further comprising prioritizing the plurality of requests according to objective criteria. 10. The method of claim 1, further comprising selecting the at least one of the plurality of reviewing resources based on characteristics of respective ones of the content items. 11. A system for content filtering, comprising: a plurality of client terminals each having communication links to a wide area network; a plurality of local filtering agents, each operatively associated with a respective one of the client terminals so as to control presentation of information thereon; a reviewing portal comprising a computer connected to the wide area network, the computer configured to receive requests for review of content items from the plurality of client terminals, and to route the requests to a plurality of reviewing resources, wherein each of the reviewing resources comprises a terminal connected to the reviewing portal and configured for presenting the content items to a human reviewer for classification according to a predetermined filtering scheme. 12. The system of claim 11, further comprising a database operatively associated with the reviewing portal, the database holding human-determined classifications of content items in association with identifiers for the content items. 13. The system of claim 11, wherein the reviewing resources are further configured to display a plurality of content items together as thumbnail images, each thumbnail image corresponding to a content item. 14. The system of claim 13, wherein the reviewing resources are further configured to display a more detailed image of a content item, upon selection of a thumbnail image corresponding to the content item by a human reviewer. 15. The system of claim 11, wherein the local filtering agents are configured to control presentation of content items on respective ones of the client terminals based on classifications provided by human reviewers using the reviewing resources and a predetermined access level for the respective client terminals. 16. The system of claim 11, wherein the local filtering agents are configured to generate the requests for review of content items based on activity of respective associated client terminals. 17. The system of claim 16, wherein the local filtering agents are further configured to as to render the requests for review of content items anonymous. 18. An apparatus for content filtering, comprising: a plurality of client terminals each connected to a wide area network via a corresponding plurality of agents, each of the plurality of agents controlling access to information from the wide area network based on an access level associated with respective ones of the client terminals; and a plurality of switches each linked communicatively to respective ones of the plurality of agents, each switch having two or more states each corresponding to a different value of the access level, wherein the access level associated with respective ones of the client terminals is determined by states of respective ones of the plurality of switches. 19. The apparatus of claim 18, wherein the switches comprise software switches settable using a control application running on a central computer connected to each of the client terminals. 20. The apparatus of claim 18, wherein the switches comprise hardware switches settable at a central control panel connected to each of the client terminals.
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CROSS-REFERENCE TO RELATED APPLICATION This application claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No. 60/484,237, filed Jun. 30, 2003, which application is specifically incorporated herein, in its entirety, by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to methods and apparatus for filtering content delivered to end users over a wide-area network, for example, filtering to prevent inappropriate adult-oriented materials from being accessed by children using public or privately-shared terminals. 2. Description of Related Art Various methods are known for detecting and restricting access to undesired information distributed over wide area networks. Such methods may employ automatic keyword analysis to identify and classify written materials, and pattern recognition for classifying images. Such methods, however, suffer from the deficiency of being easily fooled or inadvertently misclassifying information, and therefore being over inclusive or under inclusive. For example, authors of “spam” messages may readily avoid spam filters by inserting a few random characters in a text string, rendering it unrecognizable to a filter but still easily understood by a human being. At the same time, it is not generally desirable for an automatic filter to screen out every bit of questionable information, as this would impede the benefit of connecting to a wide area network in the first place. Likewise, image pattern recognition may not be able to distinguish tasteful artistic or educational images from obscene materials. Pattern recognition algorithms may also be fooled to overlook targeted classes of images by including random information in an image, or by breaking an image into pieces. Meanwhile, a human reviewer may have little difficulty in discerning an intended obscene image that an automatic pattern recognition algorithm is unable to recognize. Consequently, automatic filtering methods are often relatively ineffective in screening out undesired content, such as obscene or pornographic content, or unsolicited “spam.” Even apart from the effectiveness of filtering algorithms, a further problem arises in the operation of network terminals that are accessed by different classes of people. For example, a terminal may be operated at a library or other public area for use by patrons. Such patrons may include adults or children, and it may be desirable to screen certain content for children but not for adults. Essentially the same problem may be encountered in a home, where a single terminal may be shared by members of the household of various different ages or information requirements. One or more persons, for example, a librarian, may be responsible for ensuring that the public terminal is not used inappropriately, while still being available to access unfiltered (or differently-filtered) content by qualified persons. Such persons may find that turning the filtering on or off, or otherwise adjusting filtering levels for the public terminals under their control, is too time-consuming and inconvenient. It is desirable, therefore, to provide a methods and apparatus for network filtering that overcomes these deficiencies. SUMMARY OF THE INVENTION The present invention provides a method and apparatus for network filtering that is more accurate in filtering out undesired content. In an embodiment of the invention, an apparatus is provided to make the adjustment of filtering more convenient and less time-consuming for a custodian of shared terminals. In an embodiment of the invention, a software agent is placed on an end user terminal, or somewhere between an end user terminal and wider network content that is sought to be filtered. For example, the agent may be placed on network servers for an internet service provider, or on a mail server. The agent is configured with instructions for (a) discerning between classified and unclassified content and (b) sending unclassified content to a remote central location for verification. Optionally, the agent also performs steps for protecting the privacy of the user. These steps may include, for example, removing sensitive or personal information from the unclassified content, or protecting the identity of the person requesting the unclassified information by removing or destroying any information which may make it possible to discern the identity of the requestor. Classified content may include, for example, information that has already been classified using the content filtering system. Classified information may also include any information from a verified or approved content provider. Many content providers have internal systems in place for ensuring that inappropriate content is not published using the providers' web addresses. Much of the most popular information on the internet may originate from such providers, for which further filtering is deemed unnecessary. An agent may be configured to let content from approved providers pass to the end user without any further verification, thereby speeding up the response of the system to information requests. Unclassified content, optionally with personal or identifying information removed, is then processed by one or more servers for distribution to an appropriate human reviewer in near real-time. All requests for review of unclassified content may be passed through a single portal, which may be configured to prevent unnecessary duplication of content reviews by maintaining a database of classified content. If the content has already been reviewed, the portal may send a message to the agent indicating that the content is approved for viewing, and provide a code classifying the content. The agent may then compare the status of the end user with the classification code, and permit the end user to view the content if qualified. Classification codes may be used to indicate jurisdictions in which content is controlled. For example, a code may indicate that content is “adults only” in Europe or North America, and “prohibited” in China or Afghanistan. Depending on the identify or location of the end user—which is preferably known only to the local agent—the end user may be permitted to view the content, or restricted from viewing it. Generally, it is desirable to employ a large plurality of reviewers, so that a reviewer is always available immediately, or after only a short delay. For example, the distribution server may be connected to a network of reviewing sites around the world. Unverified content may be routed to a site with immediate available capacity. Other factors may also be used to select a reviewing site. For example, some sites may specialize in reviewing content expressed in certain languages, in the review of image data, or in the review of suspected “spam” messages. Various methods may be employed to increase efficiency and speed of the human reviewers and information throughput. For example, a plurality of images may be displayed at the same time to a single reviewer in a reduced size, for example, as “thumbnail” images. This may permit a reviewer to quickly assess and approve many images at once, while being able to quickly request and obtain a full-size view of any suspected images for a more detailed review. In addition, the initial presentation of less information for each reviewed image reduces the bandwidth requirements of the system. To reduce the likelihood of errors or intentional subversion of the system, an independent review by two or more human reviewers may be required before certain information is approved. The different reviewers may be randomly selected prior to initial review, or a reviewer may flag information for further review when confirmation of a preliminary conclusion is needed. In addition, or in the alternative, approval may be conditioned on a review by a jurisdictional specialist. For example, a certain image may be reviewed and approved for viewing in the United States, while initially being considered unclassified for users in China. When one or more requests are received for the image from China, the image may be submitted for review by a specialist in Chinese jurisdictional requirements. To ensure adequate capacity for rapid review and avoid wasting of resources, review may be limited to information that is encountered or requested by multiple different users, while other information remains unclassified. For example, review could be postponed until a certain number of requests for a web page have been received, or the most popular requests may be handled first. The distribution portal may be configured to prioritize requests for reviews, in addition to distributing requests for review of content to the reviewing network. Besides providing for more accurate review and filtering of content, which should greatly enhance beneficial use of wise area networks, the system may also be configured to protect the privacy of individual network users. The reviewing network on the back end of the content-checking portal may be configured to perform all reviews without any knowledge of the end users desiring to view the data. For example, all end-user identifying information may be stripped and destroyed before content to be reviewed is passed to the reviewing network. Classification codes for specific content may be retained in a network-accessible database, from whence codes may be picked up anonymously for use by local filtering agents. In general, the invention may be properly employed to filter out information that is not desired by end users, while protecting end users' rights to privately view any desired content. In an embodiment of the invention, a custodian of a shared terminal is provided with an apparatus for conveniently controlling filtering at one or more shared network terminals from a central control location. The invention comprises one or more physical or software switches that are conveniently accessible at the central location. Each switch is provided with a communication link to a local agent for a respective one of the shared terminals. Each switch can be set in at least two distinct states, e.g., “on” or “off.” For example, a three-way switch may be set to the states “child,” “adult,” or “unfiltered.” When the switch is set to the “child” state, the local agent is configured to perform filtering of content for end users below a certain age, for example, 18 years old. In the “adult” state, the local agent is configured to permit adult content and filter illegal (e.g., obscene) content. By setting the switch to “unfiltered,” the local filtering agent may be turned off, and all available content may be viewed at the terminal. Any number of different switch states may be used. The foregoing example should suffice, however, to demonstrate convenient control of shared terminals using a centrally located bank of switches. A more complete understanding of the method and apparatus for content filtering will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiment. Reference will be made to the appended sheets of drawings which will first be described briefly. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an exemplary system for content filtering according to the invention. FIG. 2 is a flow diagram showing exemplary steps of a method for operating a local filtering agent. FIG. 3 is a flow diagram showing exemplary steps of a method for operating a reviewing portal. FIG. 4 is a flow diagram showing exemplary steps of a method for operating a reviewing resource using human reviewers to classify content. FIG. 5 is a diagram showing features of exemplary user interface display screen for use at a reviewing resource. FIG. 6 is a diagram showing an exemplary apparatus for controlling user access levels according to an aspect of the invention for use with shared network terminals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention provides a method and apparatus for content filtering, that overcomes the limitations of the prior art. In the detailed description that follows, like element numerals are used to indicate like elements appearing in one or more of the figures. FIG. 1 shows a system 100 for content filtering, comprising a plurality of client terminals (five of many shown) used by individual users to view content provided on wide area network 114 such as the internet, a portal 104 for handling requests for human review of content, a plurality of reviewing resources 106, and a content classification database 108. Any suitable computing and networking equipment may be used to construct system 100. FIG. 1 is intended to be illustrative, and not limiting, as to the specific types of devices employed. System 100 further comprises a local filtering agent, which may reside as software on client terminals of the system, for example, on clients 116. In the alternative, a local filtering agent may be installed on any suitable intermediate layer 112 between client terminals 118 and network 114. The local filtering agent is configured to intercept requests for content originating from the client terminal or terminals that it serves, as known in the art. The requests are then processed using any suitable method as described herein. Reviewing portal 104 is connected to a plurality of reviewing resources 106, either using a private network 120, or via a secure connection using network 114. The reviewing resources comprise terminals 122a-d (four of many shown), which may be grouped and distributed over a remote geographic area, as desired. The terminals 122a-d are suitably configured with reviewing software and I/O equipment for presenting content items to human reviewers for review, and receiving classification information for the reviewed items. Database 108 may be connected and operated using portal 104. In the alternative, database 108 may be operated by an independent database server 110 with its own connection to network 114. System 100 may be operated without storing classification information in a database, but storage of at least a portion of classification data is believed to enhance system efficiency. FIG. 2 shows a method 200 for operating a local filtering agent in conjunction with other elements of system 100. Other or different steps may also be suitable, and one of ordinary skill may readily implement such steps using any suitable programming languages and methods. Being configured to intercept content requests, at step 202, the local agent receives a request for content located on the wide area network. At step 204, the agent may check to see if the request is for content from a verified source. Many commercial providers of content maintain their own controls over published content, and content from such providers may be provided without further review. These information sources may be identified in a database available to the local agent, and recognized from the network address for the requested content. Other verification methods may also be used. For example, a check of database 108 may be performed to determine whether the requested content has already been classified. If the request is for content from a verified source or has already been classified as appropriate for the access level assigned to the requesting terminal, the content request is passed to the network in a normal fashion at step 206. If otherwise, the request is passed to a reviewing portal for further processing at step 208. The reviewing portal may be configured to handle a large volume of such requests, process the requests as desired, and route a request for content review to a human reviewer. Before sending the request to the portal, the local agent may remove any identifying information from the request so as to render it anonymous. The classification itself is handled by other elements of the system, so after passing the request on, the agent need only wait for notification that the content has been reviewed and classified. While waiting, the agent may cause a message to be provided to the end user, indicating that the content has been submitted for review. At step 210, the local agent obtains the classification from the human reviewer. This may be done in any suitable manner. For example, the classification may be transmitted directly from the reviewing resource or the portal. More preferably, the local agent receives a notification that the classification is ready, and then obtains the classification anonymously from the database 108. The classification is associated with an identifier for the requested content, e.g., a URL, and may indicate various kinds of information, such as a legal classification for the material. For example, “adults only” “safe for children,” and so forth. Classification may vary by legal jurisdiction. At step 212, the local agent compares the classification for the content with the access level for the user terminal. The access level may be determined, for example, in association with a user identity, such as may be determined from a user account as known in the art. In the alternative, or in addition, the access level may be determined using a settable switch as described later in this specification. If the user is authorized to receive the requested information, as determined by comparing the access level to the content classification, the request may be passed to the network at step 206. In the alternative, the agent may cache the requested content while waiting for the classification to be received, and provide the cached content as soon as authorization is confirmed. If the user is not authorized to view the content, the agent may cause alternative content to be presented at step 214. For example, the agent may cause the a message to be displayed, notifying the user that the classification of the content exceeds the user's authorized access level. FIG. 3 shows exemplary steps of a method 300 for handling requests for review of content, for example, such as may be performed using reviewing portal 104 of system 100. At step 302, a request for review of content is received. Such a request need only identify the content that is requested for review, for example by using a URL. To detect the use of identical URL's for different content items, some small portion of the item may be sampled and stored with the URL or other identifier to confirm identity of content. At step 304, a classification database may be queried to determine whether the requested content has already been classified. If the content has already been classified, the agent may be notified that a classification is available, or the classification may be provided directly to the agent. If the content has not been classified, various tests may be performed at step 308, to determine whether the content qualifies for review, or what level of priority is to be assigned to it. For example, certain information sources or local agents may receive higher priority than others. For further example, priority may be assigned based on the number of requests received for particular content, or in any other desired fashion. Certain content may not qualify for review at all; for example, content that is written in a language not understood by the reviewing resources, that is otherwise not readily decipherable, or for which no qualified reviewers are available. If the content does not qualify for review, a suitable notice may be provided to the local agent at step 306. At step 310, a suitable reviewing resource is selected. Various selection criterion may be used to make a selection. For example, legal jurisdiction, language, type of content, available reviewing capacity, and so forth, may be used to select an appropriate reviewing resource. Generally, it may be preferable to route a request for review to the first available reviewing resource that is qualified to review the content item for the jurisdiction of interest. A reviewing portal or other centralized router of requests for review may maintain communication with the reviewing resources so that available capacity is known in real time, or near real-time. At step 314, notice of completed review may be received. In the alternative, or in addition, the classification and an associated identifier for the content item may be provided to a classification database, to the local requesting agent, to the reviewing portal, or any combination of the foregoing. In an embodiment of the invention, a classification database is updated by the reviewing resource, and notice is provided to the local agent, either directly, or via the reviewing resource at step 318. In an alternative embodiment, no notice is provided directly to the local agent, to protect the identity of the requesting user. Instead, the requesting agent may anonymously check the classification database at intervals, to receive the classification or other notice of the status of the review. FIG. 4 shows exemplary steps of a method 400 for reviewing content using a reviewing resource according to the invention. At step 402, information is obtained for review. This may comprise the entire content item, or some portion of it. In the case of content that may contain personal identifying information, for example, email messages, such information may be removed at or prior to being received by the reviewing resource. The information may also be sanitized to remove computer viruses, worms, or other undesirable executable information, prior to being accessed. If such executables are detected, their presence may be noted. For example, the content item may be classed as “infected,” and no further review undertaken. Such processing may also be performed prior to providing the information to the reviewing resource. However, it may be advantageous to provide the network address for the content item to the reviewing resource, instead of the information to be reviewed. In such case, it may be advantageous for the reviewing resource to perform its own initial processing of the content item, prior to presenting it to a human reviewer. At step 404, the reviewing resource may queue the request for review, using any suitable queuing system. It is anticipated that some reviewing resources may employ large pluralities of human reviewers, whose qualifications and areas of specialization may differ, and in communication with each other using a suitable network. One of ordinary skill may devise a suitable queuing system to ensure that a content item is expeditiously reviewed by a qualified reviewer. At step 406, the content item, or some portion of it, is presented to a human reviewer using any suitable user interface. For example, multiple content items may be presented together as thumbnail images to a reviewer, who may then quickly select questionable items for closer review, while quickly classifying the content items not selected for further review. Various automatic or semi-automatic tools may also be used to assist a human reviewer. For example, key words may be highlighted in textual documents, or a content item may be tentatively classified using any suitable automatic method, and its classification confirmed by a human reviewer. Any other suitable user interface or method for presentation may also be used. Tools may also be provide to permit rapid consultation of multiple reviewers for difficult items, or for quality control. For example, the reviewing system may request subsequent re-classification of randomly selected items as a check on reviewers' consistency and quality of review. At step 408, a classification is received from the human reviewer. For example, the reviewer may perform certain actions using a user interface, such as pressing defined keys on a keyboard or touching defined areas of a touchscreen, to quickly assign a classification to a content item. The review history of a given item, for example, date and person's reviewing and method of review, may be recorded. Greater weight may be given to classifications based on input from multiple reviewers or using more detailed methods of review. At step 410, the reviewing resource provides the classification assigned by a human reviewer and an associated identifier for the content item in any suitable manner as described elsewhere above. FIG. 5 shows, in a schematic form, exemplary screen shots 502, 504 such as may be generated by a user interface for a reviewing resource. Screen 502 shows a plurality of thumbnail images 506, each representing some portion of a content item. Many people have the ability to quickly scan a large plurality of similar items and discern the presence of exceptional or questionable material. If all the items are of the same classification, (e.g., “child-safe,” “spam,” “obscene”), the reviewer may confirm this quickly with a single action, such as a keystroke or selecting a touch-button 508. If a reviewer is unsure about a particular item, for example, thumbnail image 510, the reviewer may select the image, causing a second review screen 504 to appear. Screen 504 may provide a more detailed view 512 of the content item, with a plurality of controls 514 for rapid classification of the item. For example, each of controls 514 may be used to signal a different classification for the item after a detailed review. A control button may also be used to request confirmation from another reviewer. While screen shots suitable for touchscreen devices are illustrated, any other suitable interface may also be used. Using appropriate tools for increasing the accuracy and efficiency of human review, it is anticipated that the incremental cost of classifying a given content item may become insignificant, and readily justified by the savings associated with the detection and removal of undesirable information. Further savings may be realized by employing reviewers in areas with low labor costs. As previously described, it is necessary to define access levels at the client end of a flexible filtering system, to determine whether a given client terminal is authorized to view requested content. In the case of public or other shared terminals, ensuring that the access level is correctly set for the person currently using the terminal may be burdensome for custodians of the shared terminals. FIG. 6 shows an exemplary system 600 in which access levels for a plurality of public or shared terminals may conveniently be controlled. System 600 comprises a plurality of client terminals 602a-c connected to a corresponding plurality of switches 606a-c. Any number of terminals and corresponding switches may be used, with each terminal corresponding to a switch. Switches 606a-b are preferably placed in a central location, such as in a bank 604, convenient for the custodian of the terminals. Switches 606a-b may be implemented as hardware switches, or as software switches whose state can be changed using a suitable user interface. Each switch may be set in one of at least three different states. System 600 is configured such that the access level for each client terminal is determined by the state of its corresponding switch. In FIG. 6, three distinct states are shown for each switch, although the invention is not limited thereby. Terminal 602a is set to a first access level, corresponding to the state of switch 606a. Terminals 602b, c are set to second and third access levels, respectively, corresponding to second and third states of switches 606b, c. One of ordinary skill may readily implement a switching system as shown in FIG. 6 using any suitable hardware and software. Having thus described a preferred embodiment of a method and apparatus for content filtering, it should be apparent to those skilled in the art that certain advantages of the within system have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention. The invention is defined by the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to methods and apparatus for filtering content delivered to end users over a wide-area network, for example, filtering to prevent inappropriate adult-oriented materials from being accessed by children using public or privately-shared terminals. 2. Description of Related Art Various methods are known for detecting and restricting access to undesired information distributed over wide area networks. Such methods may employ automatic keyword analysis to identify and classify written materials, and pattern recognition for classifying images. Such methods, however, suffer from the deficiency of being easily fooled or inadvertently misclassifying information, and therefore being over inclusive or under inclusive. For example, authors of “spam” messages may readily avoid spam filters by inserting a few random characters in a text string, rendering it unrecognizable to a filter but still easily understood by a human being. At the same time, it is not generally desirable for an automatic filter to screen out every bit of questionable information, as this would impede the benefit of connecting to a wide area network in the first place. Likewise, image pattern recognition may not be able to distinguish tasteful artistic or educational images from obscene materials. Pattern recognition algorithms may also be fooled to overlook targeted classes of images by including random information in an image, or by breaking an image into pieces. Meanwhile, a human reviewer may have little difficulty in discerning an intended obscene image that an automatic pattern recognition algorithm is unable to recognize. Consequently, automatic filtering methods are often relatively ineffective in screening out undesired content, such as obscene or pornographic content, or unsolicited “spam.” Even apart from the effectiveness of filtering algorithms, a further problem arises in the operation of network terminals that are accessed by different classes of people. For example, a terminal may be operated at a library or other public area for use by patrons. Such patrons may include adults or children, and it may be desirable to screen certain content for children but not for adults. Essentially the same problem may be encountered in a home, where a single terminal may be shared by members of the household of various different ages or information requirements. One or more persons, for example, a librarian, may be responsible for ensuring that the public terminal is not used inappropriately, while still being available to access unfiltered (or differently-filtered) content by qualified persons. Such persons may find that turning the filtering on or off, or otherwise adjusting filtering levels for the public terminals under their control, is too time-consuming and inconvenient. It is desirable, therefore, to provide a methods and apparatus for network filtering that overcomes these deficiencies.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a method and apparatus for network filtering that is more accurate in filtering out undesired content. In an embodiment of the invention, an apparatus is provided to make the adjustment of filtering more convenient and less time-consuming for a custodian of shared terminals. In an embodiment of the invention, a software agent is placed on an end user terminal, or somewhere between an end user terminal and wider network content that is sought to be filtered. For example, the agent may be placed on network servers for an internet service provider, or on a mail server. The agent is configured with instructions for (a) discerning between classified and unclassified content and (b) sending unclassified content to a remote central location for verification. Optionally, the agent also performs steps for protecting the privacy of the user. These steps may include, for example, removing sensitive or personal information from the unclassified content, or protecting the identity of the person requesting the unclassified information by removing or destroying any information which may make it possible to discern the identity of the requestor. Classified content may include, for example, information that has already been classified using the content filtering system. Classified information may also include any information from a verified or approved content provider. Many content providers have internal systems in place for ensuring that inappropriate content is not published using the providers' web addresses. Much of the most popular information on the internet may originate from such providers, for which further filtering is deemed unnecessary. An agent may be configured to let content from approved providers pass to the end user without any further verification, thereby speeding up the response of the system to information requests. Unclassified content, optionally with personal or identifying information removed, is then processed by one or more servers for distribution to an appropriate human reviewer in near real-time. All requests for review of unclassified content may be passed through a single portal, which may be configured to prevent unnecessary duplication of content reviews by maintaining a database of classified content. If the content has already been reviewed, the portal may send a message to the agent indicating that the content is approved for viewing, and provide a code classifying the content. The agent may then compare the status of the end user with the classification code, and permit the end user to view the content if qualified. Classification codes may be used to indicate jurisdictions in which content is controlled. For example, a code may indicate that content is “adults only” in Europe or North America, and “prohibited” in China or Afghanistan. Depending on the identify or location of the end user—which is preferably known only to the local agent—the end user may be permitted to view the content, or restricted from viewing it. Generally, it is desirable to employ a large plurality of reviewers, so that a reviewer is always available immediately, or after only a short delay. For example, the distribution server may be connected to a network of reviewing sites around the world. Unverified content may be routed to a site with immediate available capacity. Other factors may also be used to select a reviewing site. For example, some sites may specialize in reviewing content expressed in certain languages, in the review of image data, or in the review of suspected “spam” messages. Various methods may be employed to increase efficiency and speed of the human reviewers and information throughput. For example, a plurality of images may be displayed at the same time to a single reviewer in a reduced size, for example, as “thumbnail” images. This may permit a reviewer to quickly assess and approve many images at once, while being able to quickly request and obtain a full-size view of any suspected images for a more detailed review. In addition, the initial presentation of less information for each reviewed image reduces the bandwidth requirements of the system. To reduce the likelihood of errors or intentional subversion of the system, an independent review by two or more human reviewers may be required before certain information is approved. The different reviewers may be randomly selected prior to initial review, or a reviewer may flag information for further review when confirmation of a preliminary conclusion is needed. In addition, or in the alternative, approval may be conditioned on a review by a jurisdictional specialist. For example, a certain image may be reviewed and approved for viewing in the United States, while initially being considered unclassified for users in China. When one or more requests are received for the image from China, the image may be submitted for review by a specialist in Chinese jurisdictional requirements. To ensure adequate capacity for rapid review and avoid wasting of resources, review may be limited to information that is encountered or requested by multiple different users, while other information remains unclassified. For example, review could be postponed until a certain number of requests for a web page have been received, or the most popular requests may be handled first. The distribution portal may be configured to prioritize requests for reviews, in addition to distributing requests for review of content to the reviewing network. Besides providing for more accurate review and filtering of content, which should greatly enhance beneficial use of wise area networks, the system may also be configured to protect the privacy of individual network users. The reviewing network on the back end of the content-checking portal may be configured to perform all reviews without any knowledge of the end users desiring to view the data. For example, all end-user identifying information may be stripped and destroyed before content to be reviewed is passed to the reviewing network. Classification codes for specific content may be retained in a network-accessible database, from whence codes may be picked up anonymously for use by local filtering agents. In general, the invention may be properly employed to filter out information that is not desired by end users, while protecting end users' rights to privately view any desired content. In an embodiment of the invention, a custodian of a shared terminal is provided with an apparatus for conveniently controlling filtering at one or more shared network terminals from a central control location. The invention comprises one or more physical or software switches that are conveniently accessible at the central location. Each switch is provided with a communication link to a local agent for a respective one of the shared terminals. Each switch can be set in at least two distinct states, e.g., “on” or “off.” For example, a three-way switch may be set to the states “child,” “adult,” or “unfiltered.” When the switch is set to the “child” state, the local agent is configured to perform filtering of content for end users below a certain age, for example, 18 years old. In the “adult” state, the local agent is configured to permit adult content and filter illegal (e.g., obscene) content. By setting the switch to “unfiltered,” the local filtering agent may be turned off, and all available content may be viewed at the terminal. Any number of different switch states may be used. The foregoing example should suffice, however, to demonstrate convenient control of shared terminals using a centrally located bank of switches. A more complete understanding of the method and apparatus for content filtering will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiment. Reference will be made to the appended sheets of drawings which will first be described briefly.
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20040630
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20121016
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20050602
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66715.0
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GMAHL, NAVNEET K
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METHOD AND APPARATUS FOR CONTENT FILTERING
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UNDISCOUNTED
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ACCEPTED
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10,882,725
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ACCEPTED
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Athletic shoe with bottom opening
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A shoe having an open interior, a plate positioned between the bottom of the shoe and a portion of the upper, and at least one opening extending from the bottom of the shoe into the midsole for providing air communication with the interior of the upper. In one embodiment, the opening has a height as measured from the bottom of the shoe along a vertical central axis that is greater than one-half the thickness of the rear sole. In another embodiment, the opening extends through the plate.
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1. A shoe comprising: a bottom, at least a portion of which is ground-engaging; an upper having a forward region, an arch region, a heel region and an open interior; a midsole secured below the upper, the midsole including a rear sole secured below the heel region of the upper, the rear sole having a thickness; a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions, the plate being positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper; and at least one opening extending from the bottom of the shoe into the midsole, the at least one opening being in air communication with the interior of the upper, the opening having a height as measured from the bottom of the shoe along a vertical central axis that is greater than one-half the thickness of the rear sole. 2. The shoe of claim 1, further including a substantially air-tight enclosure located at least in part between a portion of the upper and a portion of the bottom of the shoe, the air-tight enclosure having a top, a bottom and a vertical central axis passing through the top and the bottom of the air-tight enclosure. 3. The shoe of claim 1, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 4. The shoe of claim 3, wherein the midsole includes a forward sole, the inflated cushion being located in the forward sole. 5. The shoe of claim 3, wherein at least a portion of the inflated cushion is transparent. 6. The shoe of claim 3, wherein the inflated cushion has at least one exterior portion that is exposed to and visible from outside the shoe. 7. The shoe of claim 6, wherein the at least one exposed and visible portion of the inflated cushion spans a major longitudinal axis of the shoe from a medial side of the major longitudinal axis of the shoe to a lateral side of the major longitudinal axis of the shoe. 8. The shoe of claim 3, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the inflated cushion completely surrounding the vertical central axis of the rear sole in a plane substantially perpendicular to the vertical central axis of the rear sole. 9. The shoe of claim 1, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being completely surrounded by at least one inflated cushion in a plane perpendicular to the vertical central axis of the rear sole. 10. The shoe of claim 1, wherein the rear sole includes only one inflated cushion. 11. The shoe of claim 10, wherein the inflated cushion includes only one chamber. 12. The shoe of claim 1, wherein at least a portion of the plate is capable of being deflected in a direction substantially perpendicular to the major longitudinal axis of the shoe. 13. The shoe of claim 1, wherein the interior portion of the plate is capable of being deflected relative to at least a portion of the peripheral portions of the plate in a direction substantially perpendicular to a major longitudinal axis of the shoe. 14. The shoe of claim 1, wherein one of the peripheral portions of the plate is proximate a medial side of the shoe, one of the peripheral portions of the plate is proximate a lateral side of the shoe and one of the peripheral portions of the plate is proximate a rear of the shoe. 15. The shoe of claim 1, wherein the rear sole has a perimeter, a rearward portion and an opposite forward portion connected below the heel region, the rear sole having a bottom surface at least a portion of which is ground-engaging, the bottom surface of the rear sole including at least one substantially planar portion and at least two portions non-planar with the at least one substantially planar portion, the non-planar portions being positioned proximate the perimeter of the rear sole and separated from each other by other portions of the bottom surface of the rear sole, each of the non-planar portions being inclined upwardly from another portion of the bottom surface of the rear sole in a direction toward the perimeter of the rear sole, one of the at least two non-planar portions being proximate the rearward portion of the rear sole, and at least a portion of another of the at least two non-planar portions being proximate the forward portion of the rear sole. 16. The shoe of claim 1, wherein the plate extends under at least a majority of the area occupied by the heel region. 17. The shoe of claim 1, wherein the plate extends under at least two-thirds of the area occupied by the heel region. 18. The shoe of claim 1, wherein the plate extends under substantially the entire area occupied by the heel region. 19. The shoe of claim 1, further including a heel support including a wall extending vertically at least in part, the wall being exposed to and visible from outside the shoe, the wall including a top, a bottom and at least one window in the wall between the top and the bottom of the wall. 20. The shoe of claim 19, wherein the heel support is formed of a material different from the material of the ground-engaging portion of the bottom of the shoe. 21. The shoe of claim 19, wherein the heel support is made of a durable plastic material. 22. The shoe of claim 19, wherein the heel support includes a rim proximate the top of the wall, the rim extending inwardly at least in part and having a lower surface oriented toward the bottom of the shoe. 23. The shoe of claim 22, wherein the lower surface of the rim is substantially parallel with the upper surface of the plate. 24. The shoe of claim 22, wherein the rim overlies only the peripheral portions of the plate. 25. The shoe of claim 22, wherein the heel support has a top and the rear sole has a width from a medial side of the shoe to a lateral side of the shoe, the rim defining an opening in the top of the heel support having a dimension from the medial side of the shoe to the lateral side of the shoe that is greater than one-half the width of the rear sole. 26. The shoe of claim 22, wherein the heel support includes a portion extending upwardly from the rim on at least one of a medial side of the shoe, a lateral side of the shoe and a rear of the shoe. 27. The shoe of claim 22, wherein the heel support includes a portion extending upwardly from the rim on each of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 28. The shoe of claim 26, wherein the upwardly extending portion above the rim is exposed to and visible from outside the shoe. 29. The shoe of claim 26, wherein the upwardly extending portion above the rim is exposed to and visible from the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 30. The shoe of claim 19, wherein the plate is integral with at least a portion of the heel support. 31. The shoe of claim 30, wherein the plate is integral with the heel support on at least a portion of a medial side of the shoe and at least a portion of a lateral side of the shoe. 32. The shoe of claim 30, wherein the plate is integral with the heel support on at least a portion of a medial side of the shoe, at least a portion of a lateral side of the shoe and at least a portion of a rear of the shoe. 33. The shoe of claim 1, wherein the plate is made of a durable plastic material. 34. The shoe of claim 1, wherein the plate includes at least one opening therethrough. 35. The shoe of claim 1, wherein the plate includes a plurality of openings therethrough. 36. The shoe of claim 19, wherein the plate is permanently attached to the heel support. 37. The shoe of claim 19, wherein the plate is integrally formed with the heel support. 38. The shoe of claim 19, wherein the at least one window includes a plurality of windows. 39. The shoe of claim 38, wherein two of the windows are directly opposite one another. 40. The shoe of claim 19, wherein the at least one window is located on at least one of a medial side of the shoe, a lateral side of the shoe and a rear of the shoe. 41. The shoe of claim 19, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the rim including an upper surface opposite the lower surface and an interior edge connecting the upper and lower surfaces of the rim, the interior edge being oriented at least in part toward the vertical central axis of the rear sole. 42. The shoe of claim 1, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having a portion that is non-ground-engaging, the non-ground-engaging portion of the lower surface of the arch bridge being visible from outside of the shoe. 43. The shoe of claim 42, wherein the non-ground-engaging portion of the lower surface of the arch bridge is visible from the bottom of the shoe. 44. The shoe of claim 42, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 45. The shoe of claim 42, wherein the plate is made of the same material as the arch bridge. 46. The shoe of claim 19, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having a portion that is non-ground-engaging, the non-ground-engaging portion of the lower surface of the arch bridge being visible from outside of the shoe. 47. The shoe of claim 46, wherein the arch bridge is integrally formed with the heel support. 48. The shoe of claim 46, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 49. The shoe of claim 42, wherein at least a rearward portion of the non-ground-engaging portion of the lower surface of the arch bridge proximate a medial side of the shoe is inclined upwardly in a direction toward a front of the shoe. 50. The shoe of claim 42, further including at least one wall integral with the arch bridge proximate at least one of a medial side of the shoe and a lateral side of the shoe and extending in an upwardly direction from the arch bridge, the at least one wall of the arch bridge being visible at least in part from outside the shoe. 51. A shoe comprising: a bottom, at least a portion of which is ground-engaging; an upper having a forward region, an arch region, a heel region and an open interior; a midsole secured below the upper, the midsole including a rear sole secured below the heel region of the upper; a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions, the plate being positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper; at least one opening extending from the bottom of the shoe into the midsole, the at least one opening being in air communication with the interior of the upper; and at least one inflated cushion positioned between at least a portion of the bottom of the shoe and at least a portion of the upper, the inflated cushion having a top, a bottom, an exterior side, and a vertical central axis passing through the top and the bottom of the inflated cushion. 52. The shoe of claim 51, wherein the midsole includes a forward sole, the inflated cushion being located in the forward sole. 53. The shoe of claim 51, wherein at least a portion of the inflated cushion is transparent. 54. The shoe of claim 51, wherein the inflated cushion has at least one exterior portion that is exposed to and visible from outside the shoe. 55. The shoe of claim 54, wherein the at least one exposed and visible portion of the inflated cushion spans a major longitudinal axis of the shoe from a medial side of the major longitudinal axis of the shoe to a lateral side of the major longitudinal axis of the shoe. 56. The shoe of claim 51, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the inflated cushion completely surrounding the central axis of the rear sole in a plane substantially perpendicular to the vertical central axis of the rear sole. 57. The shoe of claim 51, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the central axis of the rear sole being completely surrounded by at least one inflated cushion in a plane perpendicular to the vertical central axis of the rear sole. 58. The shoe of claim 51, wherein the at least one inflated cushion is a single cushion located in the rear sole. 59. The shoe of claim 58, wherein the single cushion is located entirely within the rear sole. 60. The shoe of claim 58, wherein the inflated cushion includes only one chamber. 61. The shoe of claim 51, wherein at least a portion of the plate is capable of being deflected in a direction substantially perpendicular to the major longitudinal axis of the shoe. 62. The shoe of claim 51, wherein the interior portion of the plate is capable of being deflected relative to at least a portion of the peripheral portions of the plate in a direction substantially perpendicular to a major longitudinal axis of the shoe. 63. The shoe of claim 51, wherein one of the peripheral portions of the plate is proximate a medial side of the shoe, one of the peripheral portions of the plate is proximate a lateral side of the shoe and one of the peripheral portions of the plate is proximate a rear of the shoe. 64. The shoe of claim 51, wherein the rear sole has a perimeter, a rearward portion and an opposite forward portion connected below the heel region, the rear sole having a bottom surface at least a portion of which is ground-engaging, the bottom surface of the rear sole including at least one substantially planar portion and at least two portions non-planar with the at least one substantially planar portion, the non-planar portions being positioned proximate the perimeter of the rear sole and separated from each other by other portions of the bottom surface of the rear sole, each of the non-planar portions being inclined upwardly from another portion of the bottom surface of the rear sole in a direction toward the perimeter of the rear sole, one of the at least two non-planar portions being proximate the rearward portion of the rear sole, and at least a portion of another of the at least two non-planar portions being proximate the forward portion of the rear sole. 65. The shoe of claim 51, wherein the plate extends under at least a majority of the area occupied by the heel region. 66. The shoe of claim 51, wherein the plate extends under at least two-thirds of the area occupied by the heel region. 67. The shoe of claim 51, wherein the plate extends under substantially the entire area occupied by the heel region. 68. The shoe of claim 51, further including a heel support including a wall extending vertically at least in part, the wall being exposed to and visible from outside the shoe, the wall including a top, a bottom and at least one window in the wall between the top and the bottom of the wall. 69. The shoe of claim 68, wherein the heel support is formed of a material different from the material of the ground-engaging portion of the bottom of the shoe. 70. The shoe of claim 68, wherein the heel support is made of a durable plastic material. 71. The shoe of claim 68, wherein the heel support includes a rim proximate the top of the wall, the rim extending inwardly at least in part and having a lower surface oriented toward the bottom of the shoe. 72. The shoe of claim 71, wherein the lower surface of the rim is substantially parallel with the upper surface of the plate. 73. The shoe of claim 71, wherein the rim overlies only the peripheral portions of the plate. 74. The shoe of claim 71, wherein the heel support has a top and the rear sole has a width from a medial side of the shoe to a lateral side of the shoe, the rim defining an opening in the top of the heel support having a dimension from the medial side of the shoe to the lateral side of the shoe that is greater than one-half the width of the rear sole. 75. The shoe of claim 71, wherein the heel support includes a portion extending upwardly from the rim on at least one of a medial side of the shoe, a lateral side of the shoe and a rear of the shoe. 76. The shoe of claim 71, wherein the heel support includes a portion extending upwardly from the rim on each of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 77. The shoe of claim 75, wherein the upwardly extending portion above the rim is exposed to and visible from outside the shoe. 78. The shoe of claim 75, wherein the upwardly extending portion above the rim is exposed to and visible from the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 79. The shoe of claim 68, wherein the plate is integral with at least a portion of the heel support. 80. The shoe of claim 79, wherein the plate is integral with the heel support on at least a portion of a medial side of the shoe and at least a portion of a lateral side of the shoe. 81. The shoe of claim 79, wherein the plate is integral with the heel support on at least a portion of a medial side of the shoe, at least a portion of a lateral side of the shoe and at least a portion of a rear of the shoe. 82. The shoe of claim 51, wherein the plate is made of a durable plastic material. 83. The shoe of claim 51, wherein the plate includes at least one opening therethrough. 84. The shoe of claim 51, wherein the plate includes a plurality of openings therethrough. 85. The shoe of claim 68, wherein the plate is permanently attached to the heel support. 86. The shoe of claim 68, wherein the plate is integrally formed with the heel support. 87. The shoe of claim 68, wherein the at least one window includes a plurality of windows. 88. The shoe of claim 87, wherein two of the windows are directly opposite one another. 89. The shoe of claim 68, wherein the at least one window is located on at least one of a medial side of the shoe, a lateral side of the shoe and a rear of the shoe. 90. The shoe of claim 68, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the rim including an upper surface opposite the lower surface and an interior edge connecting the upper and lower surfaces of the rim, the interior edge being oriented at least in part toward the vertical central axis of the rear sole. 91. The shoe of claim 51, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having a portion that is non-ground-engaging, the non-ground-engaging portion of the lower surface of the arch bridge being visible from outside of the shoe. 92. The shoe of claim 91, wherein the non-ground-engaging portion of the lower surface of the arch bridge is visible from the bottom of the shoe. 93. The shoe of claim 91, wherein the plate is made of the same material as the arch bridge. 94. The shoe of claim 68, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having a portion that is non-ground-engaging, the non-ground-engaging portion of the lower surface of the arch bridge being visible from outside of the shoe. 95. The shoe of claim 94, wherein the arch bridge is integrally formed with the heel support. 96. The shoe of claim 91, wherein at least a rearward portion of the non-ground-engaging portion of the lower surface of the arch bridge proximate a medial side of the shoe is inclined upwardly in a direction toward a front of the shoe. 97. The shoe of claim 91, further including at least one wall integral with the arch bridge proximate at least one of a medial side of the shoe and a lateral side of the shoe and extending in an upwardly direction from the arch bridge, the at least one wall of the arch bridge being visible at least in part from outside the shoe. 98. A shoe comprising: a bottom, at least a portion of which is ground-engaging; an upper having a forward region, an arch region, a heel region and an open interior; a midsole secured below the upper, the midsole including a rear sole secured below the heel region of the upper; and a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions, the plate being positioned between at least a portion of the bottom of the shoe and a portion of the upper, the plate having at least one opening therein that permits air communication between the open interior of the upper and the bottom of the shoe. 99. The shoe of claim 98, further including a substantially air-tight enclosure located at least in part between a portion of the upper and a portion of the bottom of the shoe, the air-tight enclosure having a top, a bottom and a vertical central axis passing through the top and the bottom of the air-tight enclosure. 100. The shoe of claim 98, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 101. The shoe of claim 100, wherein the midsole includes a forward sole, the inflated cushion being located in the forward sole. 102. The shoe of claim 100, wherein at least a portion of the inflated cushion is transparent. 103. The shoe of claim 100, wherein the inflated cushion has at least one exterior portion that is exposed to and visible from outside the shoe. 104. The shoe of claim 103, wherein the at least one exposed and visible portion of the inflated cushion spans a major longitudinal axis of the shoe from a medial side of the major longitudinal axis of the shoe to a lateral side of the major longitudinal axis of the shoe. 105. The shoe of claim 100, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the inflated cushion completely surrounding the vertical central axis of the rear sole in a plane substantially perpendicular to the vertical central axis of the rear sole. 106. The shoe of claim 98, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being completely surrounded by at least one inflated cushion in a plane perpendicular to the vertical central axis of the rear sole. 107. The shoe of claim 98, wherein the rear sole includes only one inflated cushion. 108. The shoe of claim 107, wherein the inflated cushion includes only one chamber. 109. The shoe of claim 98, wherein at least a portion of the plate is capable of being deflected in a direction substantially perpendicular to the major longitudinal axis of the shoe. 110. The shoe of claim 98, wherein the interior portion of the plate is capable of being deflected relative to at least a portion of the peripheral portions of the plate in a direction substantially perpendicular to a major longitudinal axis of the shoe. 111. The shoe of claim 98, wherein one of the peripheral portions of the plate is proximate a medial side of the shoe, one of the peripheral portions of the plate is proximate a lateral side of the shoe and one of the peripheral portions of the plate is proximate a rear of the shoe. 112. The shoe of claim 98, wherein the at least one opening includes a plurality of openings. 113. The shoe of claim 98, wherein the at least one opening is at least in part circular. 114. The shoe of claim 98, wherein the plate is positioned at least in part under the heel region of the upper. 115. The shoe of claim 98, wherein the plate extends under at least a majority of the area occupied by the heel region. 116. The shoe of claim 98, wherein the plate extends under at least two-thirds of the area occupied by the heel region. 117. The shoe of claim 98, wherein the plate extends under substantially the entire area occupied by the heel region. 118. The shoe of claim 98, wherein the rear sole has a perimeter, a rearward portion and an opposite forward portion connected below the heel region, the rear sole having a bottom surface at least a portion of which is ground-engaging, the bottom surface of the rear sole including at least one substantially planar portion and at least two portions non-planar with the at least one substantially planar portion, the non-planar portions being positioned proximate the perimeter of the rear sole and separated from each other by other portions of the bottom surface of the rear sole, each of the non-planar portions being inclined upwardly from another portion of the bottom surface of the rear sole in a direction toward the perimeter of the rear sole, one of the at least two non-planar portions being proximate the rearward portion of the rear sole, and at least a portion of another of the at least two non-planar portions being proximate the forward portion of the rear sole. 119. The shoe of claim 98, wherein the midsole includes an opening in communication with the at least one opening of the plate. 120. The shoe of claim 119, wherein the at least one opening of the plate and the at least one opening of the midsole each have a central vertical axis that are coincident with one another. 121. The shoe of claim 98, further including a heel support including a wall extending vertically at least in part, the wall being exposed to and visible from outside the shoe, the wall including a top, a bottom and at least one window in the wall between the top and the bottom of the wall. 122. The shoe of claim 121, wherein the heel support is formed of a material different from the material of the ground-engaging portion of the bottom of the shoe. 123. The shoe of claim 121, wherein the heel support is made of a durable plastic material. 124. The shoe of claim 121, wherein the heel support includes a rim proximate the top of the wall, the rim extending inwardly at least in part and having a lower surface oriented toward the bottom of the shoe. 125. The shoe of claim 124, wherein the lower surface of the rim is substantially parallel with the upper surface of the plate. 126. The shoe of claim 124, wherein the rim overlies only the peripheral portions of the plate. 127. The shoe of claim 124, wherein the heel support has a top and the rear sole has a width from a medial side of the shoe to a lateral side of the shoe, the rim defining an opening in the top of the heel support having a dimension from the medial side of the shoe to the lateral side of the shoe that is greater than one-half the width of the rear sole. 128. The shoe of claim 124, wherein the heel support includes a portion extending upwardly from the rim on at least one of a medial side of the shoe, a lateral side of the shoe and a rear of the shoe. 129. The shoe of claim 124, wherein the heel support includes a portion extending upwardly from the rim on each of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 130. The shoe of claim 128, wherein the upwardly extending portion above the rim is exposed to and visible from outside. 131. The shoe of claim 128, wherein the upwardly extending portion above the rim is exposed to and visible from the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 132. The shoe of claim 121, wherein the plate is integral with at least a portion of the heel support. 133. The shoe of claim 132, wherein the plate is integral with the heel support on at least a portion of a medial side of the shoe and at least a portion of a lateral side of the shoe. 134. The shoe of claim 132, wherein the plate is integral with the heel support on at least a portion of a medial side of the shoe, at least a portion of a lateral side of the shoe and at least a portion of a rear of the shoe. 135. The shoe of claim 98, wherein the plate is made of a durable plastic material. 136. The shoe of claim 98, wherein the plate includes a plurality of openings therethrough. 137. The shoe of claim 121, wherein the plate is permanently attached to the heel support. 138. The shoe of claim 121, wherein the plate is integrally formed with the heel support. 139. The shoe of claim 121, wherein the at least one window includes a plurality of windows. 140. The shoe of claim 139, wherein two of the windows are directly opposite one another. 141. The shoe of claim 121, wherein the at least one window is located on at least one of a medial side of the shoe, a lateral side of the shoe and a rear of the shoe. 142. The shoe of claim 121, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the rim including an upper surface opposite the lower surface and an interior edge connecting the upper and lower surfaces of the rim, the interior edge being oriented at least in part toward the vertical central axis of the rear sole. 143. The shoe of claim 121, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 144. The shoe of claim 98, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having a portion that is non-ground-engaging, the non-ground-engaging portion of the lower surface of the arch bridge being visible from outside of the shoe. 145. The shoe of claim 144, wherein the non-ground-engaging portion of the lower surface of the arch bridge is visible from the bottom of the shoe. 146. The shoe of claim 144, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 147. The shoe of claim 144, wherein the plate is made of the same material as the arch bridge. 148. The shoe of claim 121, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having a portion that is non-ground-engaging, the non-ground-engaging portion of the lower surface of the arch bridge being visible from outside of the shoe. 149. The shoe of claim 148, wherein the arch bridge is integrally formed with the heel support. 150. The shoe of claim 148, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 151. The shoe of claim 144, wherein at least a rearward portion of the non-ground-engaging portion of the lower surface of the arch bridge proximate a medial side of the shoe is inclined upwardly in a direction toward a front of the shoe. 152. The shoe of claim 144, further including at least one wall integral with the arch bridge proximate at least one of a medial side of the shoe and a lateral side of the shoe and extending in an upwardly direction from the arch bridge, the at least one wall of the arch bridge being visible at least in part from outside the shoe.
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This is a continuation of application Ser. No. 10/447,003, filed May 28, 2003; which is a continuation of application Ser. No. 10/007,535, filed Dec. 4, 2001, now U.S. Pat. No. 6,604,300; which is a continuation of application Ser. No. 09/641,148, filed Aug. 17, 2000, now U.S. Pat. No. 6,324,772; which is a continuation of application Ser. No. 09/512,433, filed Feb. 25, 2000, now U.S. Pat. No. 6,195,916; which is a continuation of application Ser. No. 09/313,667, filed May 18, 1999, now U.S. Pat. No. 6,050,002; which is a continuation of application Ser. No. 08/723,857, filed Sep. 30, 1996, now U.S. Pat. No. 5,918,384; which is a CIP of Ser. No. 08/291,945, filed Aug. 17, 1994, now U.S. Pat. No. 5,560,126; which is a CIP of Ser. No. 08/108,065, filed Aug. 17,1993, now U.S. Pat. No. 5,615,497; all of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to an improved rear sole for footwear and, more particularly, to a rear sole for an athletic shoe with an extended and more versatile life and better performance in terms of cushioning and spring. 2. Description of the Prior Art Athletic shoes, such as those designed for running, tennis, basketball, cross-training, hiking, walking, and other forms of exercise, typically include a laminated sole attached to a soft and pliable upper. The laminated sole generally includes a resilient rubber outsole attached to a more resilient midsole usually made of polyurethane, ethylene vinyl acetate (EVA), or a rubber compound. When laminated, the sole is attached to the upper as a one-piece structure, with the rear sole being integral with the forward sole. One of the principal problems associated with athletic shoes is outsole wear. A user rarely has a choice of running surfaces, and asphalt and other abrasive surfaces take a tremendous toll on the outsole. This problem is exacerbated by the fact that most pronounced outsole wear, on running shoes in particular, occurs principally in two places: the outer periphery of the heel and the ball of the foot, with peripheral heel wear being, by far, a more acute problem. In fact, the heel typically wears out much faster than the rest of a running shoe, thus requiring replacement of the entire shoe even though the bulk of the shoe is still in satisfactory condition. Midsole compression, particularly in the case of athletic shoes, is another acute problem. As previously noted, the midsole is generally made of a resilient material to provide cushioning for the user. However, after repeated use, the midsole becomes compressed due to the large forces exerted on it, thereby causing it to lose its cushioning effect. Midsole compression is the worst in the heel area, including the area directly under the user's heel bone and the area directly above the peripheral outsole wear spot. Despite technological advancements in recent years in midsole design and construction, the benefits of such advancements can still be largely negated, particularly in the heel area, by two months of regular use. The problems become costly for the user since athletic shoes are becoming more expensive each year, with some top-of-the-line models priced at over $150.00 a pair. By contrast, with dress shoes, whose heels can be replaced at nominal cost over and over again, the heel area (midsole and outsole) of conventional athletic shoes cannot be. To date, there is nothing in the art that successfully addresses the problem of midsole compression in athletic shoes, and this problem remains especially severe in the heel area of such shoes. Another problem is that purchasers of conventional athletic shoes cannot customize the cushioning or spring in the heel of a shoe to their own body weight, personal preference, or need. They are “stuck” with whatever a manufacturer happens to provide in their shoe size. Finally, there appear to be relatively few, if any, footwear options available to those persons suffering from foot or leg irregularities, foot or leg injuries, and legs of different lengths, among other things, where there is a need for the left and right rear soles to be of a different height and/or different cushioning or spring properties. Presently, such options appear to include only custom-made shoes that are prohibitively expensive and rendered useless if the person's condition improves or deteriorates. SUMMARY OF THE INVENTION The present invention is directed to a shoe that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the shoes and shoe systems particularly pointed out in the written description and claims, as well as the appended drawings. To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the shoe includes an upper having a heel region, a rear sole secured below the heel region of the upper, and a rear sole support attached to the upper and configured to secure the rear sole below the heel region of the upper. The rear sole support includes a flexible region positioned below the heel region of the upper and above a portion of the rear sole. The flexible region is sufficiently stiff to support a user while still being sufficiently flexible to flex and spring when the user runs or walks vigorously. The flexible region has an interior portion which in its normal, unflexed state is spaced upwardly from the portion of the rear sole immediately below said interior portion, the interior portion being adapted to flex in a direction substantially perpendicular to the major longitudinal axis of the shoe as it is used. The interior portion of the flexible region preferably is elevated relative to its peripheral portion in a direction toward the heel region of the upper. In certain embodiments the flexible region is an integral part of the rear sole support. The rear sole support may include an integral arch extension extending below the upper from a position proximate the heel region of the upper through a substantial portion of the arch region of the upper to support the arch region. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of an embodiment of the shoe of the present invention. FIG. 2 is an exploded isometric view of a rear sole support, flexible member, and rear sole for the shoe of FIG. 1. FIG. 3 is an exploded isometric view of another embodiment of a rear sole support, flexible member, and rear sole for use in the shoe of the present invention. FIGS. 4-18 are isometric views of exemplary flexible member embodiments for use in the shoe of the present invention. FIG. 19 is an isometric view of another embodiment of a rear sole support for use in the shoe of the present invention. FIG. 20 is an isometric view of another embodiment of the shoe of the present invention. FIGS. 21 and 22 are isometric views of a rear sole support for the shoe of FIG. 20. FIG. 23 is an isometric view of another embodiment of the shoe of the present invention. FIG. 24 is an isometric view of a rear sole support for the shoe of FIG. 23. FIG. 25 is a side elevation view of a securing member for use in the shoe of the present invention. FIG. 26 is a partial cut-away isometric view of the securing member of FIG. 25. FIG. 27 is an exploded isometric view of an embodiment of the shoe of the present invention. FIG. 28 is an isometric view of another embodiment of the shoe of the present invention. FIG. 29 is an exploded isometric view of a heel support and rear sole for the shoe of FIG. 28. FIG. 30 is another exploded isometric view of the heel support and rear sole of FIG. 29. FIG. 31 is a side elevation view of the rear sole of FIG. 30. FIG. 32 is a side elevation view of another rear sole that can be used in the embodiment shown in FIG. 30. FIG. 33 is an exploded isometric view of a heel support, graphite insert, and rear sole for use in the shoe of the present invention. FIG. 34 is an exploded isometric view of another embodiment of a heel support, graphite insert, and rear sole for use in the shoe of the present invention. FIGS. 35-37 are views of a rear sole for use in the shoe of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts. FIG. 1 illustrates a first embodiment of the shoe of the present invention. The shoe, designated generally as 100, has a shoe upper 120, rear sole support 140, a rear sole 150, and a forward sole 160. Shoe 100 also preferably includes a flexible member 200 (FIG. 2) positioned between rear sole 150 and a heel region of upper 120. The flexible member provides spring to the user's gait cycle upon heel strike and reduces or eliminates interior rear midsole compression in that it is more durable than conventional midsole material. Upper 120 may be composed of a soft, pliable material that covers the top and sides of the user's foot during use. Leather, nylon, and other synthetics are examples of the various types of materials known in the art for shoe uppers. The particular construction of the upper is not critical to the shoe of the present invention. It may even be constructed as a sandal or may be made of molded plastic, integral with the rear sole support, as in the case of ski boots or roller blade uppers. Forward sole 160 is attached to upper 120 in a conventional manner, typically by injection molding, stitching, or gluing. Forward sole 160 typically includes two layers: an elastomeric midsole laminated to an abrasion-resistant outsole. The particular construction of the forward sole is not critical to the invention and various configurations may be used. For example, the midsole may be composed of material such as polyurethane or ethylene vinyl acetate (EVA) and may include air bladders or gel-filled tubes encased therein, and the outsole may be composed of, by means of example only, an abrasion-resistant rubber compound. Rear sole support 140 is also attached to the heel region of upper 120 in a conventional manner, such as injection molding, stitching, or gluing. Rear sole support 140 is substantially rigid and is configured to stabilize the heel region of upper 120 and secure rear sole 150 below the heel region. As shown in FIG. 2, rear sole support 140 may include an upwardly extending wall 142, referred to as a heel counter, that surrounds the periphery of the heel region of upper 120 to provide lateral stabilization. Wall 142 preferably surrounds the rear and sides of upper 120 proximate the heel region and in service supports and stabilizes the user's heel as he or she runs. Rear sole support 140 also includes a downwardly extending side wall 144 that defines a recess 146 sized to receive a portion of rear sole 150, preferably a rear sole which is removable and rotatable to several predetermined positions. Wall 144 shown in FIG. 2 is generally circular and securely contains and holds rear sole 150. A plurality of openings 145 is formed in wall 144 to facilitate securement of rear sole 150 to rear sole support 140. The components of rear sole support 140 are preferably made integral through injection molding or other conventional techniques and are preferably composed of plastic, such as a durable plastic manufactured under the name PEBAX. It is further contemplated that the rear sole support can be made from a variety of materials, including without limitation other injection-molded thermoplastic engineering resins. As shown in FIGS. 1 and 2, rear sole support 140 may include an arch extension or support 180 to provide a firm support for the arch of the foot and to alleviate potential gapping problems where sole support wall 144 would be adjacent forward sole 160. Arch extension 180 generally extends below upper 120 from the forward portion of side wall 144, through the arch region. It may extend as far as the ball of the foot. It is attached to upper 120 and forward sole 160 by gluing or other conventional methods. Arch extension 180 may be composed of the same material as the rear sole support and made integral with rear sole support 140 by injection molding. Alternatively, it may be made of the same or a different stiff but flexible material (such as carbon or fiberglass ribbons in a resin binder) and glued to rear sole support 140. Such one-piece construction of the arch extension together with the rear sole support solves another major problem, namely the tendency of an athletic shoe of conventional resilient material in the arch area to curl at the juncture of the substantially rigid rear sole support with the resilient forward sole. Shoe 100 also includes a rear sole 150 that is detachably secured to and/or rotatably positionable relative to rear sole support 140. Rear sole 150, as shown in FIG. 1, includes a rubber ground-engaging outsole 154 containing a planar area and three beveled segments or portions that soften heel strike during use. As shown, the beveled segments or portions formed on the outsole have the same shape and configuration and are positioned symmetrically about the periphery of the outside and preferably symmetrically positioned about the center of rear sole 150. As explained in more detail, rear sole 150 and the attachment features that permit rear sole 150 to be placed and locked into different positions relative to rear sole support 140 are designed and configured so that one symmetrically located beveled portion can be moved into the position previously occupied by another beveled portion. As a result, as one of the beveled portions begins to wear, rear sole 150 can be repositioned to place an unworn beveled portion in the area of the shoe where there is greater wear for a particular user. By periodically altering the position of the sole before any beveled portion is badly worn, (or any midsole material directly above the bevel is badly compressed) the life and effectiveness of the rear sole, and the entire shoe, can be significantly increased. Moreover, after a given rear sole wears beyond its point of usefulness, it can be replaced with a new sole with the same or different characteristics. Prior to replacement, it is also possible that left and right rear soles may be exchanged with each other inasmuch as left and right rear soles often exhibit opposite wear patterns. As shown in FIG. 2, rear sole 150 also includes a midsole 158 laminated to outsole 154. Midsole 158 includes a substantially cylindrical lower portion 162 and a substantially cylindrical upper portion 164 that is smaller in diameter than lower portion 162. Upper portion 164 includes a plurality of resilient knobs 165 that mate with openings 145 in rear sole support 140. As shown, the resilient knobs 165 and openings 145 are symmetrically positioned about the central axis of midsole 158 and the recess of rear sole support 140, respectively. To secure rear sole 150 to rear sole support 140, rear sole 150 is simply press-fitted into recess 146 until knobs 165 engage corresponding openings 145. This manner of locking rear sole 150 into the shoe at any one of several positions is one of several mechanical ways in which the rear sole can be removed, repositioned, and/or locked to the rear sole support or other part of a shoe. In the embodiment shown in FIG. 2, upper midsole portion 164 has a diameter at least equal to and preferably slightly larger than that of the recess into which it fits. Midsole portion 162 has a diameter substantially equal to the diameter defined by the exterior portion of circular wall 144. This configuration of elements eliminates any vertical gapping problems from occurring between the wall of the rear sole support and the peripheral surface of the rear sole. The inside diameter of a circular recess 146, as measured between the inside surfaces of its sidewalls, or the distance between the inside surface of a medial sidewall and the inside surface of an opposite lateral sidewall in the case of a non-circular recess (not shown), may actually be greater than the width of the heel region of the shoe upper as measured from the exterior surface of the medial side of the heel region of the upper to the exterior surface of the lateral side of the heel region of the upper (i.e., the heel region of the upper at its widest point). This is possible because the material used to make the rear sole support 140 and side walls is sufficiently strong and durable to permit the side walls to “flare out” to a greater width than the heel region of the upper without risk of breakage. This in turn permits the use of a larger rear sole 150 with more ground-engaging surface and, hence, more stability. (As stated, the exterior walls of the lower portion of the rear sole generally align vertically with the exterior surface of the side walls forming the recess 146). It also permits the employment of a flexible region or member with a correspondingly larger diameter, width or length because its peripheral edges optimally should align vertically with the load-bearing side walls of the recess. Such a larger flexible region or member, with a diameter, width or length greater than the width of the heel region of the upper at its widest point, creates more cushioning and/or spring for the user's heel during the gait cycle. The observations and provisions contained in this paragraph are equally applicable to the embodiments described in FIGS. 1, 2, and 3. Rear sole 150 is preferably made from two different materials: an abrasion-resistant rubber compound for ground-engaging outsole 154; and a softer, more elastomeric material such as polyurethane or ethylene vinyl acetate (EVA) for midsole 158. However, rear sole 150 could be comprised of a single homogenous material, or two materials (e.g., EVA enveloped by hard rubber), as well as a material comprising air encapsulating tubes, for example, disclosed in U.S. Pat. No. 5,005,300. For each of the discussed rear sole embodiments, the outsole and midsole materials are preferably more resilient than materials used for the rear sole support or arch extension. Detachability of rear sole 150 allows the user to change rear soles entirely when either the sole is worn to a significant degree or the user desires a different sole for desired performance characteristics for specific athletic endeavors or playing surfaces. The user can rotate the rear sole to relocate a worn section to a less critical area of the sole, and eventually replace the rear sole altogether when the sole is excessively worn. By periodically changing the position of the rear sole, more uniform wear and long life (both outsole and midsole) can be achieved. Additional longevity in wear may also be achieved by interchanging removable rear soles as between the right and left shoes, which typically exhibit opposite wear patterns. In addition, some users will prefer to change the rear soles not because of adverse wear patterns, but because of a desire for different performance characteristics or playing surfaces. For example, it is contemplated that a person using this invention in a shoe marketed as a “cross-trainer” may desire one type of rear sole for one sport, such as basketball, and another type of rear sole for another, such as running. A basketball player might require a harder and firmer rear sole for stability where quick, lateral movement is essential, whereas a runner or jogger might tend to favor increased shock absorption features achievable from a softer, more cushioned heel. Similarly, a jogger planning a run outside on rough asphalt or cement might prefer a more resilient rear sole than the type that would be suitable to run on an already resilient indoor wooden track. Rear sole performance may also depend on the weight of the user or the amount or type of cushioning desired. The present invention includes a shoe or shoe kit which includes or can accept a plurality of rear soles 150 having different characteristics and/or surface configurations, thereby providing a cross trainer shoe. As explained in more detail below, the shoe can also be designed to accept and use different flexible members in the rear sole area, to achieve optimal flex and cushioning, through the combination of a flexible member and rear sole selected to provide the most desirable flex, cushion, wear, support, and traction for a given application. In a preferred embodiment, both the rear sole and the flexible member are replaceable and a given rear sole can be locked in a plurality of separate positions relative to the recess in which it is held. Since rear sole 150 shown in FIGS. 1 and 2 is selectively positionable relative to rear sole support 140 in a single plane about an axis perpendicular to the major longitudinal axis of the shoe, it may be moved to a plurality of positions with a means provided to allow the user to secure the rear sole at each desired position. After a period of use, outsole 154 will exhibit a wear pattern at the point in which the heel first contacts the ground, when the user is running, for example. Excessive wear normally occurs at this point, and at midsole 158 generally above this point, degrading the performance of the rear sole. When the user determines that the wear in this area is significant, the user can rotate the rear sole so that the worn portion will no longer be in the location of the user's first heel strike. For the shoe shown in FIGS. 1 and 2, rotation is accomplished by detaching the rear sole and reattaching at the desired location. For the embodiment in FIG. 3 discussed below, the rear sole may be rotated without separating it from the rear sole support. The number of positions into which rear sole of FIGS. 1 and 2 can be rotated is limited by the number of knobs/openings, but is unlimited for the rear sole shown in FIG. 3. The use of other mechanical locking systems to allow selective movement and locking of the rear sole is contemplated within the spirit of the invention. Rotating the rear sole about an axis normal to the shoe's major axis to a position, for example, 180 degrees beyond its starting point, will locate the worn portion of the rear sole at or near the instep portion of the shoe. The instep portion is an area of less importance for tractioning, stability, cushioning and shock absorbing purposes. As long as the worn portion of the rear sole is rotated beyond the area of the initial heel strike, prolonged use of the rear sole is possible. The user can continue periodically to rotate the rear sole so that an unworn portion of the rear sole is located in the area of the first heel strike. The shape of rear sole can be circular, polygonal, elliptical, “sand-dollar,” elongated “sand-dollar,” or otherwise. The shape of recess 146 is formed to be compatible with the shape of the rear sole. In all embodiments, the invention includes mechanical means for selectively locking the rear sole relative to the rear sole support and upper of the shoe. Preferably, the rear sole is shaped so that at least the rear edge of the outsole has a substantially identical profile at several, or preferably each rotated position. To allow for a plurality of rotatable positions, the shape of the outsole preferably should be symmetrical about its central axis. As shown in FIG. 1, the rear sole has three beveled portions which are symmetrically positioned about its central axis. The user in this embodiment can rotate the rear sole 120.degree. and place an unworn beveled portion at the rear heel region of the shoe, where wear is often maximum. Alternatively, the rear sole could have two beveled portions, 180.degree. apart (in an oval embodiment this would have to be the case), in which event only one rotation per shoe, plus an exchange between right and left rear soles, would be possible, before replacement of rear soles would be necessary. While the above discussion is directed towards a rear sole that rotates or separates in its entirety, it is specifically contemplated that the same benefits of this invention can be achieved if only a portion of the rear sole is rotatable or removable. For example, a portion of the rear sole, e.g., the center area, may remain stationary while the periphery of the ground-engaging surface or outsole rotates and/or is detachable. As another example, the rear sole may not be removable but only rotatably positionable. In a preferred embodiment of the invention, the shoe of the present invention includes a flexible region 200 that is positioned above the rear sole and has a central portion that in its normal unflexed state is spaced upwardly from the portion of the shoe (rear sole support, or rear sole) immediately below it. The flexible region 200 is designed to provide a preselected degree of flex, cushioning, and spring, to thereby reduce or eliminate heel-center midsole compression found in conventional materials. Flexible region 200 is made of stiff, but flexible, material. Examples of materials that may be used in the manufacture of flexible member 200 include the following: graphite; fiberglass; graphite (carbon) fibers set in a resin (i.e. acrylic resin) binder; fiberglass fibers set in a resin (i.e. acrylic resin) binder; a combination of graphite (carbon) fibers and fiberglass fibers set in a resin (i.e. acrylic resin) binder; nylon; glass-filled nylon; epoxy; polypropylene; polyethylene; acrylonitrile butadiene styrene (ABS); other types of injection-molded thermoplastic engineering resins; spring steel; and stainless spring steel. The flexible region 200 can be incorporated into other elements of the shoe or can be a separate flexible member or plate. As shown in FIG. 2, flexible member 200 can be in the form of a plate supported at its peripheral region by an upward facing top surface of rear sole support 140. In this embodiment, the member or plate 200 is positioned between the rear sole 150 and the heel portion of upper 120. A ledge 148 may be formed in rear sole support 140 to support and laterally stabilize flexible member 200. The flexible member may also be permanently attached to the top or bottom of the rear sole support or detachably secured to the shoe upper and removable through a pocket formed in the material (not shown) typically located on the bottom surface of the upper, or it can be exposed and removed after removing the sock liner or after lifting the rear portion of the sock liner. Alternatively, it may be totally exposed as in the case of flexible member 200 shown in FIG. 18, wherein the U-shaped cushioning member may have direct contact with the user's heel without an intervening sock liner in the heel portion of the shoe. The removability of the flexible member allows the use of several different types of flexible members of varying stiffness or composition and, therefore, can be adapted according to the weight of the runner, the ability of the runner, the type of exercise involved, or the amount of cushioning and/or spring desired in the heel of the shoe. Rear sole 150 may have a concave top surface 167, as shown in FIG. 2. Therefore, when the rear sole is attached to the rear sole support, the top surface of the rear sole does not come into contact with the flexible member when the flexible member deflects within its designed range of flex. As a result, the middle of the flexible member can flex under the weight of the user without being impeded by rear sole 150. Flexible member 200 thus acts like a trampoline to provide extra spring in the user's gait in addition to minimizing, or preventing, midsole compression in the central portion of the rear sole. A second preferred embodiment is shown in FIG. 3. In this embodiment, a rear sole 250 is identical to rear sole 150 shown in FIG. 2 except that it has a groove 254 below upper midsole portion 252, instead of knobs 165. A rear sole support 240 includes a downwardly extending wall 244 that has a serrated bottom edge 246 and a threaded inner surface 248. Rear sole support 240 also includes an upper rim 249. The embodiment of FIG. 3 also indicates a threaded ring 400. Ring 400 includes a threaded outer surface 410 that mates with threaded inner surface 248 of rear sole support 240. The ring also includes an outwardly and inwardly extending flange 412 that presses against serrated bottom edge 246 when the ring is screwed into the rear sole support. The bottom surface of flange 412 includes anchors 414, and may also be serrated to further grip the rear sole to prevent rotation. The ring also has two ends 416 and 418, and end 416 may have a male member and end 418 may be shaped to receive the male member to lock the two ends together. Ring 400 may be made of hard plastic or other substantially rigid materials that provide a secure engagement with rear sole support 240 and a firm foundation for supporting flexible member 200. Rear sole 250 is attached to rear sole support 240 by unlocking the ends of ring 400 and positioning ring 400 around upper midsole portion 252 of the rear sole such that flange 412 engages groove 254. Ring 400 is then firmly locked onto the rear sole by mating end 416 with end 418. Flexible member 200 is inserted into the rear sole support so that it presses against upper rim 249. Ring 400, with rear sole 250 attached, is then screwed into the rear sole support by engaging threaded surface 410 of the ring with threaded surface 248 of wall 244. The ring is then screwed into the rear sole support until serrated edge 246 of wall 244 engages flange 412 of ring 400. Serrated edge 246 serves to prevent rotation of the ring during use and the top edge of ring 400 firmly supports flexible member 200. The rear sole support sidewalls need not be continuous around the entire recess. Such sidewalls may be substantially eliminated on the lateral and medial sides of the rear sole support, or even at the rear and/or front of the rear sole support, exposing ring 400 when installed, even allowing it to protrude through the sidewalls where the openings are created. This has no effect whatsoever on the thread alignment on the inside surface of the remaining sidewalls. The advantage of doing this is that a ring with a slightly larger diameter than otherwise possible and, hence, a flexible member with a slightly larger diameter than otherwise possible may be employed. In the embodiment shown in FIG. 3, a variety of different flexible members 200 having different flex and cushioning characteristics can be selectively incorporated into the shoe. Flexible member 200, once incorporated into the shoe, is securely held in place with rear sole support 240. Preferably, the rear sole support contacts flexible member 200 only along its outer periphery, and rear sole support 240 includes an opening above the flexible member, thereby permitting the plate to protrude upwardly toward the user's heel. Moreover, because the top surface of rear sole 250 is preferably concave in shape, the central portion of the rear sole does not contact the central portion of the flexible member in its unflexed, normal position. As a result, the flexible member can also flex downward. The degree of flexing of the member can be controlled both by the selection of the material and shape of the member, as well as the relative dimensions and shape of rear sole support 240 and rear sole 250. While flexible member 200 and the corresponding recess in rear sole support 240 are circular in FIG. 3, other shapes can be utilized. Rear sole support 240 could be designed to include a recess above upper rim 249 to accept the flexible member and a mechanical means, such as a circular locking ring, similar to ring 400, to support and lock the flexible member in place. In such an embodiment, the user could change the flexible member from the inside of the shoe. Similarly, the flexible member 200 could be fixedly secured to, or incorporated as an integral part, of either the rear sole support or the rear sole. Similar configurations of an integral flexible region are within the spirit of the invention. The embodiment of FIG. 3 and other embodiments of the invention preferably provide a shoe that includes a flexible region or member which has its own preselected spring and cushioning characteristic and which is preferably removable and replaceable, a rear sole with its own pre-selected cushioning properties (both outsole and midsole) and which is preferably removable, replaceable, and capable of being locked in place at a plurality of preselected positions; a plurality of beveled portions on the outer surface of the rear sole which are preferably symmetrically located about its axis; and an interrelationship of the flexible member, rear sole support, and rear sole which permit the flexible member to freely flex to at least a predetermined degree. The flexible region and its characteristics, the rear sole and its characteristics, and the rear sole's relative location to the flexible region can be selectively altered, to provide in combination an optimal shoe for a given application. Also, because of the rear sole rotation and replacement permitted by the invention, typically heavy outsole material may be made thinner than on conventional athletic shoes, thus reducing the weight of the shoe. The invention also permits the weight of the shoe to be further reduced because the central portion of the midsole of the rear sole can be eliminated, since the flexible region of the shoe provides weight bearing and cushioning at this area. Other rear sole support/rear sole combinations for securing the rear sole to the shoe and for supporting the flexible member at or below the heel region of the upper are contemplated and fall within the spirit of this invention, as described and claimed. By means of example only, some such additional configurations are disclosed in commonly-owned U.S. patent application Ser. No. 08/291,945, now U.S. Pat. No. 5,560,126, which is incorporated herein by reference. The flexible region of the present invention is not limited to a circular shape and can be adapted to conform to the shape of the rear sole. The flexible region also need not be used only in conjunction with a detachable rear sole, but can be used with permanently attached rear soles as well. FIGS. 4-17 show various alternative embodiments of the flexible member. In each of these embodiments, the flexible member may be curved or convex in shape, or have an inwardly curved or concave bottom surface, such that the interior portion of the flexible member is elevated relative to its periphery when the flexible member is positioned in the shoe in its normal position. Each of the following flexible member embodiments may be used in conjunction with the rear sole support/rear sole combinations disclosed in FIGS. 1-3 and more generally disclosed in this disclosure in its entirety. In addition, the following disclosed embodiments of flexible members can be integrally incorporated into a portion of the shoe. In either event, the resultant shoe has a flexible region which provides a preselected flex and spring. As shown in FIG. 4, flexible member 500 has a concave under surface 502 (when viewed from its bottom) and an opposing convex upper surface, and is circular in shape. As a result, the interior portion of the flexible member 500 is elevated relative to its peripheral portion and is positioned above a portion of the rear sole of the user when supported in the shoe. Flexible members 510 and 520 shown in FIGS. 5 and 6, respectively, are similar in structure to flexible member 500 except that flexible member 510 has a bottom surface 514 and a moon-shaped notch 512 and flexible member 520 has a bottom surface 524 and two opposing moon-shaped notches 522. Notch 512 of flexible member 510 is preferably aligned with the back of the rear sole. One of notches 522 of flexible member 520 may be aligned with the back of the rear sole, or alternatively such notches may be aligned with the lateral and medial sides of the shoe. Flexible member 530 as shown in FIG. 7 is identical in structure to flexible member 520 shown in FIG. 6 except that it is not spherically convex in shape, but rather convexly curved in only one direction. The flexible member 530 alignment options are the same as those of flexible member 520. As shown in FIG. 8, flexible member 540 includes a plurality of spokes 542 each joined at one end to a hub 544 and joined at an opposite end to rim 546. The size, shape, and number of spokes is variable depending on the desired flexibility. As shown in FIG. 8, each of spokes 542 has a triangular cross-section, although the cross-section may also be square, rectangular, or any other geometrical shape. When positioned in the shoe, hub 544 is elevated relative to rim 546 such that hub 544 is closer to the heel region of the upper. The flexible members shown in FIGS. 9-12 are variations of flexible member 540 shown in FIG. 8. Flexible member 550 shown in FIG. 9 is identical in structure to flexible member 540, but includes webbing 552 covering the top surface of flexible member 550 and joining each of spokes 542 to reinforce flexible member 550. Webbing 552 may be injection molded with the rest of flexible member. Flexible member 560 shown in FIG. 10 is similar in structure to flexible member 540 shown in FIG. 8; however, spokes 562 decrease in thickness between hub 564 and the central portion of each of the spokes 562 and then increase in thickness from the central portion toward rim 566. Flexible member 570, shown in FIG. 11, also includes a plurality of spokes 572 joined at opposite ends to hub 574 and rim 576. In this embodiment, the thickness of the spokes decreases in a direction from hub 574 toward rim 576. As shown in FIG. 11, the decreasing thickness of spokes 572 results in at least a portion of the interior portion of flexible member 570 in the area of the decreasing thickness spokes 572 being thinner than at least a portion of its peripheral edges or rim 576. Hub 574 and other portions of the center portion of the interior portion of flexible member 570 are shown as being thicker than another portion of the interior portion of flexible member 570, such as in the area of decreased spoke thickness. As shown in FIG. 11, center portion or hub 574 and peripheral edge or rim 576 may both be thicker than a portion of the interior portion of flexible member 570 between hub 574 and rim 576. In addition, webbing 578 may be placed over the top surface of flexible member 570 similar to that disclosed in FIG. 9. As shown in FIG. 11, spokes 572 are preferably oriented such that each spoke is oriented 180 degrees from an opposite spoke to provide a rib that extends substantially across flexible member 570. Whether referred to as opposite spokes 572 or a rib the thickness may be varied. The rib is preferable integrally formed with flexible member 570 and more preferably is on the bottom surface or concave surface of flexible member 570. As can be seen in FIG. 11, a hole may be provided through flexible member 570 and more particularly, through the center or hub 574. As can be further determined from FIG. 11, flexible member 570 may be substantially planar in shape, but is not conical in shape. FIG. 12 illustrates a housing 580 for supporting the flexible member, in this example, flexible member 560. Housing 580 has an L-shaped cross-section to support the bottom and side surfaces of rim 566. Housing 580 may be inserted into the shoe heel with flexible member 560 or may be permanently affixed to the rear sole support. In either case, housing 580 acts as a reinforcement for limiting or eliminating lateral movement of flexible member 560 during use. This may have the effect of making the center of the flexible member more springy. It may also allow the member to be made of thinner and/or lighter weight material. FIGS. 13 and 14 show further variations of flexible plate 500 shown in FIG. 4. While flexible plate 500 has a generally uniform thickness at any given radius, flexible plate 585 shown in FIG. 13 decreases in thickness from the center of the member toward its periphery. Flexible member 590 shown in FIG. 14, on the other hand, is thicker near the center and at the periphery, but thinner therebetween. FIGS. 15-17A disclose flexible members composed of carbon ribbons set in a resin binder. Alternatively, they may be fiberglass ribbons or a combination of carbon and fiberglass ribbons. Ribbons made of other types of fiber may also be used. Flexible member 600 includes radially or diametrically projecting ribbons 602, either emanating from the center of flexible member toward its periphery or, preferably, passing through the center from a point on the periphery to a diametrically opposite point on the periphery. These ribbons 602 are fixed in position by a resin binder 604 known in the art. Flexible member 610 shown in FIG. 16 also includes carbon ribbons 602 set in a resin binder 604, but further includes a rim 606 comprised of ribbon preset in the resin binder and defining the periphery of flexible member 610. Flexible member 620 shown in FIG. 17 is identical to flexible member 610 shown in FIG. 16 except that it further includes a circular ribbon 608 disposed in resin binder 604 and circumscribing the center of flexible member 620. The flexible member shown in FIG. 17A is identical to the flexible member 610 shown in FIG. 17 except that it has fewer spokes and further includes a plurality of circular ribbons 608 spaced radially from the center of the member and disposed in the resin binder 604. Flexible members 600, 610, and 620 may be convex in shape so that the center of the flexible member is raised relative to its outer perimeter, when placed in the shoe. They may also have a U-shaped cushioning member placed on or secured to their top surface like that shown in FIG. 18. Since it is contemplated that the flexible member will be composed of graphite or other stiff, but flexible, material, it is preferable to cushion the impact of the user's heel against the flexible member during use. As shown in FIG. 18, a substantially U-shaped cushioning member 650 is disposed on the top surface of flexible member 500 to cushion the heel upon impact. The U-shaped cushioning member is shaped to generally conform to the shape of the user's heel. Thus, the open end of the U-shape is oriented toward the front of the shoe. Cushioning member 650 may be composed of polyurethane or EVA or may be an air-filled or gel-filled member. Cushioning member 650 can be affixed to flexible member 500 by gluing, or may be made integral with flexible member 500 in an injection molding process. If injection molded, cushioning member 650 would be made of the same material as flexible member 500. To decrease the stiffness of cushioning member 650 in this instance, small holes (not shown) may be drilled in cushioning member 650 to weaken it and thereby allow it to depress more readily upon impact and more uniformly with flexible member 500. The cushioning member 650 described above can be incorporated into a shoe having any of the various flexible regions disclosed in this application and drawings, as well as other shoes falling within the scope of the claims. If cushioning member 650 is used, the shoe sock liner, which generally provides cushioning, may be thinner in the heel area or may terminate at the forward edge of cushioning member 650. If cushioning member 650 is not used, the sock liner may extend to the rear of the shoe and may be shaped to conform to the user's heel on its top surface and the flexible member on its bottom surface. Its bottom surface may also compensate for gaps formed by the flexible member. For example, the sock liner may have a concave bottom surface in the heel area to correspond to those flexible members having convex upper surfaces. In each of the above-described embodiments, the flexible member is illustrated as a separate component of the shoe which can be removed from the shoe and replaced by a similar or different flexible member, as desired. In each of the embodiments the central portion of the flexible member is raised relative to its outer perimeter so that when placed in the shoe, the interior portion in its normal state does not touch the rear sole support and/or rear sole. As a result, the interior of the flexible member will flex in response to the user's stride without first, if ever, contacting the rear sole support and/or rear sole. Such flexible member, therefore, can be used with rear soles that have a flat upper surface, as well as those that have a concave upper surface. The relative shape and positioning of the flexible member and the adjacent rear sole support or rear sole can be designed to provide the optimum flex, stiffness, and spring characteristics. However, each of the above-described flexible members may be made integral with the rear sole support, which not only decreases the number of loose parts and increases the efficiency of the manufacturing process, but also further limits the lateral displacement of the periphery of the flexible member upon deflection, potentially creating more spring in the center and/or permitting the use of thinner and/or lighter weight material. As shown in FIG. 19, rear sole support 340 is identical in structure to rear sole support 140 shown in FIG. 2 except that rear sole support 340 has a flexible region 700 that serves the same purpose and function as any of the above-described flexible members. In fact, any of the above-described flexible members may be used as flexible region 700 so long as they can be made integral with rear sole support 340. In this example, flexible region 700 is convex in shape and thus similar to flexible member 500 shown in FIG. 4. Cushioning member 650 or a modified sock liner as described above may also be used. The flexible region may be incorporated into other rear sole support embodiments as well. As an alternative to using arch extension 180, rear sole support 440 shown in FIGS. 20-22 includes a thickened tongue 447 that extends toward the ball of the foot. Thickened tongue 447 provides additional gluing surface for attaching the rear sole support to forward sole 160 and additional stiffness to the heel portion of the shoe and the arch area, thus minimizing the chances of separation of the forward sole from the rear sole support, and at the same time minimizing the tendency of the shoe to curl at the juncture of the hard rear sole support with the soft forward sole. Similar to rear sole support 240, rear sole support 440 includes a heel counter 442 and a side wall 444. Rear sole support 440 also includes a rim 448 and anchors 452 to receive and retain a rear sole with a mating groove, such as rear sole 250. Forward sole 260 is longer in this embodiment to extend back to the edge where it would abut the rear sole. Flexible region 710 is identical to flexible region 700 in FIG. 19. In another embodiment, rear sole support 460, as shown in FIGS. 23 and 24, includes a tongue 462 that is thinner and slightly smaller than tongue 447 shown in FIGS. 20-22. However, rear sole support 460 includes a curved wall 464 that has a pocket formed on its forward side for receiving a mating rear edge of forward sole 360 adjacent the rear sole support. Curved wall 464 provides a firm, smoothly contoured transition from hard-to-align resilient materials of the forward and rear soles and thereby minimizes gapping. It also provides a desirable brace or bumper for the lower portion of the rear sole when the user is running. Flexible region 720 is identical to flexible regions 700 and 710. As shown in FIGS. 25 and 26, the flexible member may also be integrated with the securing member. Securing member 750 is similar in structure and function as securing member 400 in that it includes a wall 752 with a threaded outer surface, an inwardly and outwardly extending rim 754, and anchors 756. Securing member 750 also includes a convex flexible region 760 integral with wall 752. Flexible region 760, like flexible regions 700 and 710, may incorporate any of the configurations shown in FIGS. 4-18. Securing member 750 is simply substituted for securing member 400 and flexible member 200 shown in FIG. 3 to attach rear sole 250 to rear sole support 240. However, since securing member 750 does not include mating ends 416, 418, rear sole 250 is press-fitted into securing member 70 until rear sole groove 254 mates with securing member rim 754. This may have the effect of making the center of the flexible member more springy. It may also allow the flexible member to be made of thinner and/or lighter weight material. FIG. 27 illustrates another embodiment of the shoe of the present invention. The shoe, designated generally as 820, has a shoe upper 822, a forward sole 824, a heel support 826, and a rear sole 828. The forward sole and heel support are attached to the shoe upper in a conventional manner, typically by injection molding, stitching or gluing. As shown in FIG. 27, the heel support 826 preferably includes a heel counter 827 for stabilizing a heel portion of the upper 22 above the heel support and a side wall 838 that extends downwardly from the upper and defines a recess 840 sized to receive the rear sole. The heel support may also include a substantially horizontal top wall 838′ for supporting the heel portion of the upper. Otherwise, the top of the rear sole or an insert, as will be discussed in more detail later, will support the heel portion of the upper. The components of the heel support, including heel counter 827 and the side wall 838, are preferably made integral through injection molding or other conventional techniques and are preferably composed of plastic, such as a durable plastic manufactured under the name PEBAX. Another embodiment of the present invention is shown in FIGS. 28-31. The shoe includes an upper 22, a heel support 940, a rear sole 950, and a forward sole 960. As shown in FIG. 29, the heel support 940 includes a heel counter 942, a downwardly extending wall 944 that defines a recess 946 sized to receive the rear sole, and a rim 948 formed around the lower portion of the wall and extending inwardly into the recess. Anchors 952 may be formed on the bottom surface of the rim 948 and extend downwardly toward the rear sole 950. The rear sole 950 includes a rubber ground-engaging surface 954 containing, in this embodiment, three beveled segments or edges 956. As shown in FIG. 31, the rear sole 950 also includes a midsole 958 laminated to the ground-engaging surface 954 that includes a substantially cylindrical lower portion 962 and a substantially cylindrical upper portion 964 that is smaller in diameter than the lower portion. A groove 966 is formed between these upper and lower portions and receives the rim 948 of the heel support to retain the rear sole in the heel support recess. The upper midsole portion 964 includes a spiral groove 968, as shown in FIGS. 29-31, that allows the rear sole to be screwed into the heel support. As shown in FIG. 29, a portion of the rim of the heel support is cut away at 970. The rear sole is screwed into the heel support by aligning the top of the spiral groove with an edge 972 of the rim adjacent the cut-away portion. A sharp instrument (such as a slender screwdriver), inserted through the window 974 and into the top of the spiral groove 968 may aid in the start-up process. The rear sole is then simply rotated, and the rim engages the spiral groove of the rear sole to screw the upper midsole of the rear sole into the recess. Once fully inserted, the rear sole may be rotated freely within the recess by hand, albeit with desired resistance. When the rear sole is attached to the heel support, the optional anchors sink into the lower midsole portion of the rear sole due to the weight of the user to prevent rotation of the rear sole during use. It should be noted that the configuration of the midsole 958, i.e., the upper midsole portion having a diameter equal to or slightly larger than that of the recess defined by the rim and a lower midsole portion having a diameter substantially equal to the diameter defined by the circular wall 944, further eliminates any vertical gapping problems from occurring between the wall of the heel support and the peripheral surface of the rear sole. To assist in removing the rear sole from the heel support, the two windows 974, 976 (FIG. 29) are formed in the wall of the heel support, a first window 974 above the cut-away portion of the rim and a second window 976 positioned 180 degrees around the wall of the heel support from the first window. In addition, a small indention 978 is formed on the peripheral surface of the upper midsole portion 964 at a position 180 degrees from the point at which the spiral groove 968 intersects the bottom of the upper midsole portion 964, as shown in FIG. 31. To remove the rear sole from the heel support, the rear sole is rotated in the heel support until the small indention appears in the second window 976. At this point, the bottom of the spiral groove is aligned with the center of the cut-away portion. The user, again using a screwdriver or similar instrument inserted through the window 974 into the spiral groove 968, can then simply rotate the rear sole so that the rim of the heel support engages the spiral groove. The rear sole is then simply rotated to screw the rear sole out of the heel support. It is not necessary to include a spiral groove in the rear sole for attaching and removing the rear sole from the heel support. As shown in FIG. 32, a rear sole 950 is similar to that shown in FIG. 31, but includes no spiral groove and no small indention. Because the upper portion 964 and lower portion 962 of the midsole 958 are made of a soft material, it can be press-fitted into the recess of the heel support until the rim 948 engages the groove 966. As shown in FIGS. 28-30, the shoe of the present invention also preferably includes an arch bridge 980 attached to, and integral with, the heel support 940 to provide an even firmer support for the arch of the foot and for alleviating potential gapping problems where the wall of the heel support is adjacent the forward sole. The arch bridge 980 generally extends from the rear of the recess 946 (where it attaches to the heel counter 942 and side wall 944) to the ball of the foot and is attached to the upper 22 and forward sole 960 by gluing or other conventional methods. The arch bridge 980 also is preferably composed of the same material as the heel support and is made integral with the heel support 940 by molding. Such one-piece construction of the arch bridge together with the heel support solves another major problem, and that is the tendency of an athletic shoe of conventional “full body” arch construction to curl at the juncture of the hard heel support with the resilient forward sole. Another embodiment for attaching the graphite insert is shown in FIG. 33. In this embodiment, the graphite insert 1000 is inserted through the bottom of the heel support 1040 so that the periphery of the graphite insert presses against the lower surface of an upper rim 1049 of the heel support. A plastic ring 1010 is also inserted in the recess between the graphite insert and the rim 1048. Such ring 1010 is flexible enough to allow it to be inserted into the heel support. The ring supports the periphery of the lower surface of the graphite insert. The rear sole 1050 is a screw-in type identical to the rear sole 950 shown in FIG. 31 except that it has a concave top surface to allow the graphite insert to flex during use. As shown in FIG. 33, the rim 1048 of the heel support includes two cut-away portions at 1070 and windows 1074, 1076 to allow the graphite insert and the ring to be inserted into the recess of the heel support, in addition to allowing the rear sole to be screwed onto the heel support in the same manner as contemplated by FIGS. 29, 30 and 31. The ring 1010 also has windows 1012, 1014 that are aligned with the windows 1074, 1076 when the ring is inserted into the recess. Alternatively, the rim 1048 of the heel support and the graphite insert 1000 can be “gear-shaped”, as shown in FIG. 34, to allow the graphite insert 1000 to be inserted into the heel support. Again, the ring 1010 is flexible enough to allow it to be inserted into the heel support. If additional cushioning is desired, the rear sole can be modified as shown in FIGS. 35-37. In this embodiment, a “doughnut-shaped” void 1152 is created in the middle of a rear sole 1150 to support an air-filled cushion 1170 similar in shape to an inner tube for a tire. In addition, several voids 1154 are formed around the periphery of the rear sole to reduce the weight of the rear sole and better exploit the cushioning properties of the air-filled cushion 1170 when the shoe strikes the ground during use. The voids are preferably positioned directly below the knobs 1156 to cushion the force transmitted from the heel support to the knobs. The air cushion 1170 may include a valve 1172 for inflating and deflating the cushion. It will be apparent to those skilled in the art that various modifications and variations can be made in the system of the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the claims and their equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to an improved rear sole for footwear and, more particularly, to a rear sole for an athletic shoe with an extended and more versatile life and better performance in terms of cushioning and spring. 2. Description of the Prior Art Athletic shoes, such as those designed for running, tennis, basketball, cross-training, hiking, walking, and other forms of exercise, typically include a laminated sole attached to a soft and pliable upper. The laminated sole generally includes a resilient rubber outsole attached to a more resilient midsole usually made of polyurethane, ethylene vinyl acetate (EVA), or a rubber compound. When laminated, the sole is attached to the upper as a one-piece structure, with the rear sole being integral with the forward sole. One of the principal problems associated with athletic shoes is outsole wear. A user rarely has a choice of running surfaces, and asphalt and other abrasive surfaces take a tremendous toll on the outsole. This problem is exacerbated by the fact that most pronounced outsole wear, on running shoes in particular, occurs principally in two places: the outer periphery of the heel and the ball of the foot, with peripheral heel wear being, by far, a more acute problem. In fact, the heel typically wears out much faster than the rest of a running shoe, thus requiring replacement of the entire shoe even though the bulk of the shoe is still in satisfactory condition. Midsole compression, particularly in the case of athletic shoes, is another acute problem. As previously noted, the midsole is generally made of a resilient material to provide cushioning for the user. However, after repeated use, the midsole becomes compressed due to the large forces exerted on it, thereby causing it to lose its cushioning effect. Midsole compression is the worst in the heel area, including the area directly under the user's heel bone and the area directly above the peripheral outsole wear spot. Despite technological advancements in recent years in midsole design and construction, the benefits of such advancements can still be largely negated, particularly in the heel area, by two months of regular use. The problems become costly for the user since athletic shoes are becoming more expensive each year, with some top-of-the-line models priced at over $150.00 a pair. By contrast, with dress shoes, whose heels can be replaced at nominal cost over and over again, the heel area (midsole and outsole) of conventional athletic shoes cannot be. To date, there is nothing in the art that successfully addresses the problem of midsole compression in athletic shoes, and this problem remains especially severe in the heel area of such shoes. Another problem is that purchasers of conventional athletic shoes cannot customize the cushioning or spring in the heel of a shoe to their own body weight, personal preference, or need. They are “stuck” with whatever a manufacturer happens to provide in their shoe size. Finally, there appear to be relatively few, if any, footwear options available to those persons suffering from foot or leg irregularities, foot or leg injuries, and legs of different lengths, among other things, where there is a need for the left and right rear soles to be of a different height and/or different cushioning or spring properties. Presently, such options appear to include only custom-made shoes that are prohibitively expensive and rendered useless if the person's condition improves or deteriorates.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to a shoe that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the shoes and shoe systems particularly pointed out in the written description and claims, as well as the appended drawings. To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the shoe includes an upper having a heel region, a rear sole secured below the heel region of the upper, and a rear sole support attached to the upper and configured to secure the rear sole below the heel region of the upper. The rear sole support includes a flexible region positioned below the heel region of the upper and above a portion of the rear sole. The flexible region is sufficiently stiff to support a user while still being sufficiently flexible to flex and spring when the user runs or walks vigorously. The flexible region has an interior portion which in its normal, unflexed state is spaced upwardly from the portion of the rear sole immediately below said interior portion, the interior portion being adapted to flex in a direction substantially perpendicular to the major longitudinal axis of the shoe as it is used. The interior portion of the flexible region preferably is elevated relative to its peripheral portion in a direction toward the heel region of the upper. In certain embodiments the flexible region is an integral part of the rear sole support. The rear sole support may include an integral arch extension extending below the upper from a position proximate the heel region of the upper through a substantial portion of the arch region of the upper to support the arch region. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
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20040630
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20080603
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20060608
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94490.0
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A43B1314
| 2
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BAYS, MARIE D
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ATHLETIC SHOE WITH BOTTOM OPENING
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UNDISCOUNTED
| 1
|
CONT-ACCEPTED
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A43B
| 2,004
|
|
10,882,729
|
ACCEPTED
|
Heel support for athletic shoe
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A shoe including a heel support integrally formed of a material different from the midsole material of a rear sole for supporting the foot of a user. The heel support includes a wall along at least one of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe that extends vertically at least in part and includes at least one window through which at least a portion of the midsole material of the rear sole is exposed to and visible from outside the shoe.
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1. A shoe comprising: a bottom, a medial side, a lateral side and a rear; an upper having a forward region, an arch region and a heel region; a forward sole below the forward region of the upper, the forward sole having a bottom surface that is at least in part ground-engaging; a rear sole below at least a portion of the heel region of the upper, the rear sole including a midsole material, the rear sole having a bottom surface that is at least in part ground-engaging; a heel support integrally formed of a material different from the midsole material of the rear sole, the heel support including a wall along at least one of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe, the wall extending vertically at least in part and being in air communication with and visible from the outside of the shoe, the wall including a top, a bottom and at least one window in the wall between the top and the bottom of the wall, at least a portion of the midsole material of the rear sole being in air communication with and visible from the outside of the shoe through the at least one window in the wall, the heel support including a rim proximate the top of the wall, the rim extending inwardly at least in part and having a lower surface oriented toward at least a portion of the bottom of the shoe; and an arch bridge integrally formed with the heel support, the arch bridge including a lower surface having an elevated portion that is non-ground-engaging, the elevated portion of the lower surface of the arch bridge being visible from the bottom of the shoe between the ground-engaging surfaces of the forward sole and the rear sole. 2. The shoe of claim 1, further including a substantially air-tight enclosure located at least in part between a portion of the upper and a portion of the bottom of the shoe, the air-tight enclosure having a top, a bottom and a vertical central axis passing through the top and the bottom of the air-tight enclosure. 3. The shoe of claim 2, wherein the air-tight enclosure is located in the forward sole. 4. The shoe of claim 2, wherein a portion of the air-tight enclosure is at least in part curved. 5. The shoe of claim 4, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 6. The shoe of claim 4, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially parallel with the vertical central axis of the air-tight enclosure. 7. The shoe of claim 4, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially parallel with the vertical central axis of the air-tight enclosure and in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 8. The shoe of claim 4, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 9. The shoe of claim 4, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially parallel with the vertical central axis of the air-tight enclosure. 10. The shoe of claim 4, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially parallel with the vertical central axis of the air-tight enclosure and in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 11. The shoe of claim 2, wherein at least one of the top and the bottom of the air-tight enclosure has a portion that is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 12. The shoe of claim 2, wherein each of the top and the bottom of the air-tight enclosure has a portion that is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 13. The shoe of claim 2, wherein at least a portion of the bottom of the air-tight enclosure is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 14. The shoe of claim 2, wherein at least a portion of the top of the air-tight enclosure is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 15. (canceled) 16. The shoe of claim 2, wherein the air-tight enclosure has at least one exterior portion that is in air communication with and visible from the outside of the shoe. 17. The shoe of claim 1, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 18. The shoe of claim 17, wherein the inflated cushion is located in the forward sole. 19. The shoe of claim 17, wherein the inflated cushion includes a bladder. 20. The shoe of claim 19, wherein the bladder is an air bladder. 21. The shoe of claim 17, wherein a portion of the inflated cushion is at least in part curved. 22. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 23. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially parallel to the vertical central axis of the inflated cushion. 24. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially parallel with the vertical central axis of the inflated cushion and in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 25. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 26. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially parallel with the vertical central axis of the inflated cushion. 27. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially parallel with the vertical central axis of the inflated cushion and in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 28. The shoe of claim 17, wherein at least one of the top and the bottom of the inflated cushion has a portion that is generally flat and perpendicular to the vertical central axis of the inflated cushion. 29. The shoe of claim 17, wherein each of the top and the bottom of the inflated cushion has a portion that is generally flat and perpendicular to the vertical central axis of the inflated cushion. 30. The shoe of claim 17, wherein at least a portion of the bottom of the inflated cushion is generally flat and perpendicular to the vertical central axis of the inflated cushion. 31. The shoe of claim 17, wherein at least a portion of the top of the inflated cushion is generally flat and perpendicular to the vertical central axis of the inflated cushion. 32. (canceled) 33. The shoe of claim 17, wherein the inflated cushion has at least one exterior portion that is in air communication with and visible from the outside of the shoe. 34. The shoe of claim 33, wherein the at least one exterior portion of the inflated cushion spans a major longitudinal axis of the shoe from a medial side of the major longitudinal axis of the shoe to a lateral side of the major longitudinal axis of the shoe. 35. The shoe of claim 17, wherein at least a portion of the inflated cushion is located in a forward portion of the rear sole and spans from a point on a medial side of the shoe to a point on a lateral side of the shoe. 36. The shoe of claim 17, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the inflated cushion completely surrounding the vertical central axis of the rear sole in a plane substantially perpendicular to the vertical central axis of the rear sole. 37. The shoe of claim 1, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the vertical central axis of the rear sole being completely surrounded by at least one inflated cushion in a plane perpendicular to the vertical central axis of the rear sole. 38. The shoe of claim 1, wherein the rear sole includes only one inflated cushion. 39. The shoe of claim 38, wherein the inflated cushion includes only one chamber. 40. The shoe of claim 39, wherein the chamber is located entirely within the rear sole. 41. The shoe of claim 38, wherein the forward sole includes at least one inflated cushion. 42. The shoe of claim 38, wherein the forward sole includes a plurality of inflated cushions. 43. The shoe of claim 17, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the vertical central axis of the inflated cushion being coincident with the vertical central axis of the rear sole. 44. The shoe of claim 17, wherein the inflated cushion has at least one sidewall that is in air communication with and visible from the outside of the shoe, the at least one sidewall being curved along a majority of the distance between the top and the bottom of the inflated cushion. 45. The shoe of claim 44, wherein the at least one sidewall has a generally uniform thickness. 46. The shoe of claim 17, wherein at least a portion of the inflated cushion is located proximate a lateral side of the shoe, at least a portion of the inflated cushion is located proximate a medial side of the shoe and at least a portion of the inflated cushion is located proximate a rear of the shoe, the portions being in communication with one another. 47. The shoe of claim 21, wherein the at least in part curved portion of the inflated cushion has the shape of an arc of a circle. 48. The shoe of claim 17, wherein the inflated cushion has an interior chamber with a height parallel to the vertical central axis of the inflated cushion, the interior chamber having a maximum cross sectional dimension perpendicular to the vertical central axis of the inflated cushion that is greater than the height of the interior chamber. 49. The shoe of claim 17, further including a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being in contact with at least a portion of the heel support. 50. The shoe of claim 1, further including a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being in contact with at least a portion of the heel support. 51. The shoe of claim 50, wherein at least a portion of the plate is capable of being deflected in a direction substantially perpendicular to a major longitudinal axis of the shoe. 52. The shoe of claim 50, wherein the interior portion of the plate is capable of being deflected relative to at least a portion of the peripheral portions of the plate in a direction substantially perpendicular to a major longitudinal axis of the shoe. 53. The shoe of claim 50, wherein one of the peripheral portions of the plate is proximate a medial side of the shoe and one of the peripheral portions of the plate is proximate a lateral side of the shoe. 54. The shoe of claim 50, wherein one of the peripheral portions of the plate is proximate the medial side of the shoe, one of the peripheral portions of the plate is proximate the lateral side of the shoe and one of the peripheral portions of the plate is proximate the rear of the shoe. 55. The shoe of claim 50, wherein the wall extends vertically at least in part along both the medial side of the shoe and the lateral side of the shoe, the plate having a forward one-third portion oriented toward a front of the shoe, a reward one-third portion oriented toward the rear of the shoe and a central one-third portion between the forward one-third portion and the rearward one-third portion, at least a portion of the central one-third portion of the plate being in contact with the wall proximate both the medial side of the shoe and the lateral side of the shoe. 56. The shoe of claim 50, wherein the wall extends vertically at least in part along the rear of the shoe, the plate having a forward half oriented toward a front of the shoe and a reward half oriented toward the rear of the shoe, at least a portion of the rearward half of the plate being in contact with the wall proximate the rear of the shoe. 57. The shoe of claim 50, wherein the wall extends vertically at least in part along the medial side of the shoe, the lateral side of the shoe and the rear of the shoe, at least a portion of the plate being in contact with the wall proximate the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 58. The shoe of claim 50, wherein the interior portion of the plate is positioned at least in part beneath the calcaneus of the wearer of the shoe. 59. The shoe of claim 58, wherein the interior portion of the plate that is positioned at least in part beneath the calcaneus of the wearer is positioned at least in part beneath the approximate center of the calcaneus of the wearer of the shoe as measured on a line generally perpendicular to the bottom of the shoe. 60. The shoe of claim 50, wherein the plate extends under at least a majority of the area occupied by the heel region. 61. The shoe of claim 50, wherein the plate extends under at least two-thirds of the area occupied by the heel region. 62. The shoe of claim 61, wherein the plate extends under substantially the entire area occupied by the heel region. 63. The shoe of claim 50, wherein the plate extends under substantially the entire area occupied by the heel region. 64. The shoe of claim 1, further including a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being connected to at least a portion of the heel support. 65. The shoe of claim 50, wherein the plate is integral with at least a portion of the heel support. 66. The shoe of claim 65, wherein the plate is integral with the heel support on at least a portion of the medial side of the shoe and at least a portion of the lateral side of the shoe. 67. The shoe of claim 65, wherein the plate is integral with the heel support on at least a portion of the medial side of the shoe, at least a portion of the lateral side of the shoe and at least a portion of the rear of the shoe. 68. The shoe of claim 50, wherein the plate is made of the same material as the arch bridge. 69. The shoe of claim 50, wherein the plate is made of a durable plastic material. 70. The shoe of claim 50, wherein the plate includes at least one opening therethrough. 71. The shoe of claim 50, wherein the plate includes a plurality of openings therethrough. 72. The shoe of claim 50, wherein the plate is permanently attached to the heel support. 73. The shoe of claim 50, wherein the plate is integrally formed with the heel support. 74. The shoe of claim 50, wherein the peripheral portions of the plate have an outer contour that fits an outer contour of the bottom of the wall of the heel support. 75. The shoe of claim 50, wherein the peripheral portions of the plate have an outer contour that corresponds to an outer contour of the bottom of the wall of the heel support. 76. The shoe of claim 50, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the peripheral portions of the plate completely surrounding the vertical central axis of the rear sole. 77. The shoe of claim 50, wherein the plate has a thickness between the upper surface and the lower surface of the plate, the thickness being substantially uniform. 78. The shoe of claim 50, wherein at least one of the upper and the lower surfaces of the plate is generally planar. 79. The shoe of claim 50, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom, and a vertical central axis passing through the top and the bottom of the inflated cushion. 80. The shoe of claim 79, wherein the rear sole includes a layer of outsole material that forms at least a portion of the ground engaging surface of the rear sole, each of the inflated cushion, the plate and the layer having a portion proximate the rear of the shoe that is curved in a plane perpendicular to the vertical central axis of the inflated cushion from the medial side of the shoe to the lateral side of the shoe, the shape of the curve of each of the rear portions of the inflated cushion, the plate and the layer being substantially the same. 81. (canceled) 82. The shoe of claim 80, wherein the curve of each of the rear portions of the inflated cushion, the plate and the layer of outsole material is substantially semi-circular. 83. The shoe of claim 50, wherein the rear sole includes only one inflated cushion. 84. The shoe of claim 83, wherein the inflated cushion includes only one chamber. 85. The shoe of claim 84, wherein the chamber is located entirely within the rear sole. 86. The shoe of claim 83, wherein the forward sole includes at least one inflated cushion. 87. The shoe of claim 83, wherein the forward sole includes a plurality of inflated cushions. 88. The shoe of claim 1, wherein the heel support is made of a durable plastic material. 89. The shoe of claim 1, wherein the at least one window generally forms the shape of a quadrilateral. 90. The shoe of claim 1, further including at least a second window. 91. The shoe of claim 90, wherein two of the windows are directly opposite one another. 92. The shoe of claim 1, wherein the at least one window includes a plurality of windows. 93. The shoe of claim 92, wherein two of the windows are directly opposite one another. 94. The shoe of claim 1, wherein the at least one window is located on at least one of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 95. The shoe of claim 1, wherein at least one of the at least one window is located on the rear of the shoe. 96. The shoe of claim 1, wherein the at least one window includes at least three windows. 97. The shoe of claim 1, wherein the at least one window includes at least four windows. 98. The shoe of claim 1, wherein the at least one window includes at least five windows. 99. The shoe of claim 1, wherein the at least one window includes at least six windows. 100. The shoe of claim 1, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the rim including an upper surface opposite the lower surface and an interior edge connecting the upper and lower surfaces of the rim, the interior edge being oriented at least in part toward the vertical central axis of the rear sole. 101. The shoe of claim 1, wherein the heel support has a top and the rear sole has a width from the medial side of the shoe to the lateral side of the shoe, the rim defining an opening in the top of the heel support having a dimension from the medial side of the shoe to the lateral side of the shoe that is greater than one-half the width of the rear sole. 102. The shoe of claim 50, wherein the lower surface of the rim is substantially parallel with the upper surface of the plate. 103. The shoe of claim 50, wherein the rim overlies only the peripheral portions of the plate. 104. The shoe of claim 1, wherein the heel support includes a portion extending upwardly from the rim on at least one of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 105. The shoe of claim 1, wherein the heel support includes a portion extending upwardly from the rim on each of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 106. The shoe of claim 104, wherein the upwardly extending portion above the rim is in air communication with and visible from the outside of the shoe. 107. The shoe of claim 104, wherein the upwardly extending portion above the rim is in air communication with and visible from the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 108. The shoe of claim 1, wherein the heel support is located between a material forming a portion of the forward sole and the ground-engaging surface of the rear sole. 109. The shoe of claim 1, wherein the heel support completely separates a material forming a portion of the forward sole from the ground-engaging surface of the rear sole. 110. The shoe of claim 1, wherein at least a portion of the ground-engaging surfaces of the forward sole and the rear sole are made of a rubber material. 111. The shoe of claim 1, wherein the ground-engaging surface of the rear sole includes an opening therein that exposes a plastic material, the plastic material being visible from the bottom of the shoe. 112. The shoe of claim 1, wherein the bottom surface of the rear sole has a perimeter and a center located beneath the approximate center of the calcaneus of the wearer of the shoe, the rear sole further including a rearward portion and an opposite forward portion below the heel region of the upper, the bottom surface having at least two portions which are beveled in different directions away from the center of the rear sole, each of the beveled portions defining at least in part the perimeter of the rear sole. 113. The shoe of claim 112, wherein one of the at least two beveled portions is located at least in part in the forward portion of the rear sole and is oriented at least in part toward a front of the shoe. 114. The shoe of claim 112, wherein one of the at least two beveled portions is located at least in part in the rearward portion of the rear sole and is oriented at least in part toward the rear of the shoe. 115. The shoe of claim 112, wherein one of the at least two beveled portions is located at least in part in the forward portion of the rear sole and is oriented at least in part toward a front of the shoe and one of the at least two beveled portions is located at least in part in the rearward portion of the rear sole and is oriented at least in part toward the rear of the shoe. 116. The shoe of claim 1, wherein the rear sole has a perimeter, a rearward portion and an opposite forward portion below the heel region, the bottom surface of the rear sole including at least one substantially planar portion and at least two portions non-planar with the at least one substantially planar portion, the non-planar portions being positioned proximate the perimeter of the rear sole and separated from each other by other portions of the bottom surface of the rear sole, each of the non-planar portions being inclined upwardly from another portion of the bottom surface of the rear sole in a direction toward the perimeter of the rear sole, one of the at least two non-planar portions being proximate the rearward portion of the rear sole, and at least a portion of another of the at least two non-planar portions being proximate the forward portion of the rear sole. 117. The shoe of claim 1, wherein the elevated portion of the lower surface of the arch bridge extends from a medial side of the shoe to a lateral side of the shoe. 118. The shoe of claim 1, wherein the elevated portion of the lower surface of the arch bridge extends below at least a substantial portion of the arch region of the upper. 119. The shoe of claim 1, wherein the elevated portion of the lower surface of the arch bridge extends below substantially the entire arch region of the upper. 120. The shoe of claim 1, wherein at least a forward portion of the elevated portion of the lower surface of the arch bridge proximate the medial side of the shoe is inclined upwardly in a direction toward the rear of the shoe. 121. The shoe of claim 1, wherein at least a rearward portion of the elevated portion of the lower surface of the arch bridge proximate a medial side of the shoe is inclined upwardly in a direction toward a front of the shoe. 122. The shoe of claim 1, further including at least one wall integral with the arch bridge proximate at least one of a medial side of the shoe and a lateral side of the shoe and extending in an upwardly direction from the arch bridge, the at least one wall of the arch bridge being visible at least in part from outside the shoe. 123. The shoe of claim 1, wherein the arch bridge is formed of the same material as the heel support. 124. The shoe of claim 1, wherein the arch bridge and the heel support are molded as a one-piece construction. 125. The shoe of claim 1, wherein the arch bridge comprises at least a portion of the bottom of the shoe. 126. The shoe of claim 1, wherein the upper includes an open interior, further including at least one opening extending in an upwardly direction from the bottom of the shoe, the at least one opening being in air communication with the open interior of the upper. 127. A shoe comprising: a bottom, a medial side, a lateral side and a rear; an upper having a forward region, an arch region and a heel region; a forward sole below the forward region of the upper, the forward sole having a bottom surface that is at least in part ground-engaging; a rear sole below at least a portion of the heel region of the upper, the rear sole including a midsole material, the rear sole having a bottom surface that is at least in part ground-engaging; a heel support integrally formed of a durable plastic material, the heel support including a wall proximate at least one of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe, the wall extending vertically at least in part and being in air communication with and visible from the outside of the shoe, the wall including a top, a bottom and at least three windows between the top and the bottom of the wall, one of the at least three windows being located along the medial side of the shoe, one of the at least three windows being located along the lateral side of the shoe and one of the at least three windows being located along the rear of the shoe, the heel support including a rim proximate the top of the wall, the rim extending inwardly at least in part and having a lower surface oriented toward a portion of the bottom of the shoe. 128. The shoe of claim 127, further including a substantially air-tight enclosure located at least in part between a portion of the upper and a portion of the bottom of the shoe, the air-tight enclosure having a top, a bottom and a vertical central axis passing through the top and the bottom of the air-tight enclosure. 129. The shoe of claim 128, wherein the air-tight enclosure is located in the forward sole. 130. The shoe of claim 128, wherein a portion of the air-tight enclosure is at least in part curved. 131. The shoe of claim 130, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 132. The shoe of claim 130, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially parallel with the vertical central axis of the air-tight enclosure. 133. The shoe of claim 130, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially parallel with the vertical central axis of the air-tight enclosure and in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 134. The shoe of claim 130, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 135. The shoe of claim 130, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially parallel with the vertical central axis of the air-tight enclosure. 136. The shoe of claim 130, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially parallel with the vertical central axis of the air-tight enclosure and in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 137. The shoe of claim 128, wherein at least one of the top and the bottom of the air-tight enclosure has a portion that is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 138. The shoe of claim 128, wherein each of the top and the bottom of the air-tight enclosure has a portion that is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 139. The shoe of claim 128, wherein at least a portion of the bottom of the air-tight enclosure is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 140. The shoe of claim 128, wherein at least a portion of the top of the air-tight enclosure is generally flat and perpendicular to the vertical central axis of the air-tight enclosure when. 141. (canceled) 142. The shoe of claim 128, wherein the air-tight enclosure has at least one exterior portion that is in air communication with and visible from the outside of the shoe. 143. The shoe of claim 127, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 144. The shoe of claim 143, wherein the inflated cushion is located in the forward sole. 145. The shoe of claim 143, wherein the inflated cushion includes a bladder. 146. The shoe of claim 145, wherein the bladder is an air bladder. 147. The shoe of claim 143, wherein a portion of the inflated cushion is at least in part curved. 148. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 149. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially parallel with the vertical central axis of the inflated cushion. 150. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially parallel with the vertical central axis of the inflated cushion and in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 151. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 152. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially parallel with the vertical central axis of the inflated cushion. 153. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially parallel with the vertical central axis of the inflated cushion and in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 154. The shoe of claim 143, wherein at least one of the top and the bottom of the inflated cushion has a portion that is generally flat and perpendicular to the vertical central axis of the inflated cushion. 155. The shoe of claim 143, wherein each of the top and the bottom of the inflated cushion has a portion that is generally flat and perpendicular to the vertical central axis of the inflated cushion. 156. The shoe of claim 143, wherein at least a portion of the bottom of the inflated cushion is generally flat and perpendicular to the vertical central axis of the inflated cushion. 157. The shoe of claim 143, wherein at least a portion of the top of the inflated cushion is generally flat and perpendicular to the vertical central axis of the inflated cushion. 158. (canceled) 159. The shoe of claim 143, wherein the inflated cushion has at least one exterior portion that is in air communication with and visible from the outside of the shoe. 160. The shoe of claim 159, wherein the at least one exterior and visible portion of the inflated cushion spans a major longitudinal axis of the shoe from a medial side of the major longitudinal axis of the shoe to a lateral side of the major longitudinal axis of the shoe. 161. The shoe of claim 143, wherein at least a portion of the inflated cushion is located in a forward portion of the rear sole and spans from a point on a medial side of the shoe to a point on a lateral side of the shoe. 162. The shoe of claim 143, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the inflated cushion completely surrounding the vertical central axis of the rear sole in a plane substantially perpendicular to the vertical central axis of the rear sole. 163. The shoe of claim 127, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being completely surrounded by at least one inflated cushion in a plane perpendicular to the vertical central axis of the rear sole. 164. The shoe of claim 127, wherein the rear sole includes only one inflated cushion. 165. The shoe of claim 164, wherein the inflated cushion includes only one chamber. 166. The shoe of claim 165, wherein the chamber is located entirely within the rear sole. 167. The shoe of claim 164, wherein the forward sole includes at least one inflated cushion. 168. The shoe of claim 164, wherein the forward sole includes a plurality of inflated cushions. 169. The shoe of claim 143, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the vertical central axis of the inflated cushion being coincident with the vertical central axis of the rear sole. 170. The shoe of claim 143, wherein the inflated cushion has at least one sidewall that is in air communication with and visible from the outside of the shoe, the at least one sidewall being curved along a majority of the distance between the top and the bottom of the inflated cushion. 171. The shoe of claim 170, wherein the at least one sidewall has a generally uniform thickness. 172. The shoe of claim 143, wherein at least a portion of the inflated cushion is located proximate the lateral side of the shoe, at least a portion of the inflated cushion is located proximate the medial side of the shoe and at least a portion of the inflated cushion is located proximate the rear of the shoe, the portions being in communication with one another. 173. The shoe of claim 147, wherein the at least in part curved portion of the inflated cushion has the shape of an arc of a circle. 174. The shoe of claim 143, wherein the inflated cushion has an interior chamber with a height parallel to the vertical central axis of the inflated cushion, the interior chamber having a maximum cross sectional dimension perpendicular to the vertical central axis of the inflated cushion that is greater than the height of the interior chamber. 175. The shoe of claim 143, further including a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being in contact with at least a portion of the heel support. 176. The shoe of claim 127, further including a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being in contact with at least a portion of the heel support. 177. The shoe of claim 176, wherein at least a portion of the plate is capable of being deflected in a direction substantially perpendicular to a major longitudinal axis of the shoe. 178. The shoe of claim 176, wherein the interior portion of the plate is capable of being deflected relative to at least a portion of the peripheral portions of the plate in a direction substantially perpendicular to a major longitudinal axis of the shoe. 179. The shoe of claim 176, wherein one of the peripheral portions of the plate is proximate a medial side of the shoe and one of the peripheral portions of the plate is proximate a lateral side of the shoe. 180. The shoe of claim 176, wherein one of the peripheral portions of the plate is proximate the medial side of the shoe, one of the peripheral portions of the plate is proximate the lateral side of the shoe and one of the peripheral portions of the plate is proximate the rear of the shoe. 181. The shoe of claim 176, wherein the wall extends vertically at least in part along both the medial side of the shoe and the lateral side of the shoe, the plate having a forward one-third portion oriented toward a front of the shoe, a reward one-third portion oriented toward the rear of the shoe and a central one-third portion between the forward one-third portion and the rearward one-third portion, at least a portion of the central one-third portion of the plate being in contact with the wall proximate both the medial side of the shoe and the lateral side of the shoe. 182. The shoe of claim 176, wherein the wall extends vertically at least in part along the rear of the shoe, the plate having a forward half oriented toward a front of the shoe and a reward half oriented toward the rear of the shoe, at least a portion of the rearward half of the plate being in contact with the wall proximate the rear of the shoe. 183. The shoe of claim 176, wherein the wall extends vertically at least in part along the medial side of the shoe, the lateral side of the shoe and the rear of the shoe, at least a portion of the plate being in contact with the wall proximate the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 184. The shoe of claim 176, wherein the interior portion of the plate is positioned at least in part beneath the calcaneus of the wearer of the shoe. 185. The shoe of claim 184, wherein the interior portion of the plate that is positioned at least in part beneath the calcaneus of the wearer is positioned at least in part beneath the approximate center of the calcaneus of the wearer of the shoe as measured on a line generally perpendicular to the bottom of the shoe. 186. The shoe of claim 176, wherein the plate extends under at least a majority of the area-occupied by the heel region. 187. The shoe of claim 176, wherein the plate extends under at least two-thirds of the area occupied by the heel region. 188. The shoe of claim 187, wherein the plate extends under substantially the entire area occupied by the heel region. 189. The shoe of claim 176, wherein the plate extends under substantially the entire area occupied by the heel region. 190. The shoe of claim 127, further including a plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being connected to at least a portion of the heel support. 191. The shoe of claim 176, wherein the plate is integral with at least a portion of the heel support. 192. The shoe of claim 191, wherein the plate is integral with the heel support on at least a portion of the medial side of the shoe and at least a portion of the lateral side of the shoe. 193. The shoe of claim 191, wherein the plate is integral with the heel support on at least a portion of the medial side of the shoe, at least a portion of the lateral side of the shoe and at least a portion of the rear of the shoe. 194. The shoe of claim 176, further including an arch bridge positioned below at least a portion of the arch region of the upper, the plate being made of the same material as the arch bridge. 195. The shoe of claim 176, wherein the plate is made of a durable plastic material. 196. The shoe of claim 176, wherein the plate includes at least one opening therethrough. 197. The shoe of claim 176, wherein the plate includes a plurality of openings therethrough. 198. The shoe of claim 176, wherein the plate is permanently attached to the heel support. 199. The shoe of claim 176, wherein the plate is integrally formed with the heel support. 200. The shoe of claim 176, wherein the peripheral portions of the plate have an outer contour that fits an outer contour of the bottom of the wall of the heel support. 201. The shoe of claim 176, wherein the peripheral portions of the plate have an outer contour that corresponds to an outer contour of the bottom of the wall of the heel support. 202. The shoe of claim 176, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the peripheral portions of the plate completely surrounding the vertical central axis of the rear sole. 203. The shoe of claim 176, wherein the plate has a thickness between the upper surface and the lower surface of the plate, the thickness being substantially uniform. 204. The shoe of claim 176, wherein at least one of the upper and the lower surfaces of the plate is generally planar. 205. The shoe of claim 176, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 206. The shoe of claim 205, wherein the rear sole includes a layer of outsole material that forms at least a portion of the ground engaging surface of the rear sole, each of the inflated cushion, the plate and the layer having a portion proximate the rear of the shoe that is curved in a plane perpendicular to the vertical central axis of the inflated cushion from the medial side of the shoe to the lateral side of the shoe, the shape of the curve of each of the rear portions of the inflated cushion, the plate and the layer being substantially the same. 207. (canceled) 208. The shoe of claim 206, wherein the curve of each of the rear portions of the inflated cushion, the plate and the layer of outsole material is substantially semi-circular. 209. The shoe of claim 176, wherein the rear sole includes only one inflated cushion. 210. The shoe of claim 209, wherein the inflated cushion includes only one chamber. 211. The shoe of claim 210, wherein the chamber is located entirely within the rear sole. 212. The shoe of claim 209, wherein the forward sole includes at least one inflated cushion. 213. The shoe of claim 209, wherein the forward sole includes a plurality of inflated cushions. 214. The shoe of claim 127, wherein two of the at least three windows are directly opposite each other. 215. The shoe of claim 127, wherein each of the at least three windows exposes a portion of the midsole material of the rear sole. 216. The shoe of claim 127, wherein the at least three windows include at least four windows. 217. The shoe of claim 216, wherein each of the at least four windows exposes a portion of the midsole material of the rear sole. 218. The shoe of claim 127, wherein the at least three windows include at least five windows. 219. The shoe of claim 218, wherein each of the at least five windows exposes a portion of the midsole material of the rear sole. 220. The shoe of claim 127, wherein the at least three windows include at least six windows. 221. The shoe of claim 220, wherein each of the at least six windows exposes a portion of the midsole material of the rear sole. 222. The shoe of claim 127, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the rim including an upper surface opposite the lower surface and an interior edge connecting the upper and lower surfaces of the rim, the interior edge being oriented at least in part toward the vertical central axis of the rear sole. 223. The shoe of claim 127, wherein the heel support has a top and the rear sole has a width from the medial side of the shoe to the lateral side of the shoe, the rim defining an opening in the top of the heel support having a dimension from the medial side of the shoe to the lateral side of the shoe that is greater than one-half the width of the rear sole. 224. The shoe of claim 176, wherein the lower surface of the rim is substantially parallel with the upper surface of the plate. 225. The shoe of claim 176, wherein the rim overlies only the peripheral portions of the plate. 226. The shoe of claim 127, wherein the heel support includes a portion extending upwardly from the rim on at least one of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 227. The shoe of claim 127, wherein the heel support includes a portion extending upwardly from the rim on each of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 228. The shoe of claim 226, wherein the upwardly extending portion above the rim is in air communication with and visible from the outside of the shoe. 229. The shoe of claim 226, wherein the upwardly extending portion above the rim is in air communication with and visible from the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 230. The shoe of claim 127, wherein the heel support is located between a material forming a portion of the forward sole and the ground-engaging surface of the rear sole. 231. The shoe of claim 127, wherein the heel support completely separates a material forming a portion of the forward sole from the ground-engaging surface of the rear sole. 232. The shoe of claim 127, wherein at least a portion of the ground-engaging surfaces of the forward sole and the rear sole is made of a rubber material. 233. The shoe of claim 127, wherein the ground-engaging surface of the rear sole includes an opening therein that exposes a plastic material, the plastic material being visible from the bottom of the shoe. 234. The shoe of claim 127, wherein the bottom surface of the rear sole has a perimeter and a center located beneath the approximate center of the calcaneus of the wearer of the shoe, the rear sole further including a rearward portion and an opposite forward portion below the heel region of the upper, the bottom surface having at least two portions which are beveled in different directions away from the center of the rear sole, each of the beveled portions defining at least in part the perimeter of the rear sole. 235. The shoe of claim 234, wherein one of the at least two beveled portions is located at least in part in the forward portion of the rear sole and is oriented at least in part toward a front of the shoe. 236. The shoe of claim 234, wherein one of the at least two beveled portions is located at least in part in the rearward portion of the rear sole and is oriented at least in part toward the rear of the shoe. 237. The shoe of claim 234, wherein one of the at least two beveled portions is located at least in part in the forward portion of the rear sole and is oriented at least in part toward a front of the shoe and one of the at least two beveled portions is located at least in part in the rearward portion of the rear sole and is oriented at least in part toward the rear of the shoe. 238. The shoe of claim 127, wherein the rear sole has a perimeter, a rearward portion and an opposite forward portion connected below the heel region, the bottom surface of the rear sole including at least one substantially planar portion and at least two portions non-planar with the at least one substantially planar portion, the non-planar portions being positioned proximate the perimeter of the rear sole and separated from each other by other portions of the bottom surface of the rear sole, each of the non-planar portions being inclined upwardly from another portion of the bottom surface of the rear sole in a direction toward the perimeter of the rear sole, one of the at least two non-planar portions being proximate the rearward portion of the rear sole, and at least a portion of another of the at least two non-planar portions being proximate the forward portion of the rear sole. 239. The shoe of claim 127, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having an elevated portion that is non-ground-engaging, the elevated portion of the lower surface of the arch bridge being visible from outside of the shoe. 240. The shoe of claim 239, wherein the elevated portion of the lower surface of the arch bridge is visible from the bottom of the shoe between the ground-engaging surfaces of the forward sole and the rear sole. 241. The shoe of claim 239, wherein the arch bridge comprises at least a portion of the bottom of the shoe. 242. The shoe of claim 239, wherein the arch bridge is integrally formed with the heel support. 243. The shoe of claim 239, wherein the arch bridge is formed of the same material as the heel support. 244. The shoe of claim 239, wherein the arch bridge and the heel support are molded as a one-piece construction. 245. The shoe of claim 239, wherein the elevated portion of the lower surface of the arch bridge extends from a medial side of the shoe to a lateral side of the shoe. 246. The shoe of claim 239, wherein the elevated portion of the lower surface of the arch bridge extends below at least a substantial portion of the arch region of the upper. 247. The shoe of claim 239, wherein the elevated portion of the lower surface of the arch bridge extends below substantially the entire arch region of the upper. 248. The shoe of claim 239, wherein at least a forward portion of the elevated portion of the lower surface of the arch bridge proximate the medial side of the shoe is inclined upwardly in a direction toward the rear of the shoe. 249. The shoe of claim 239, wherein at least a rearward portion of the elevated portion of the lower surface of the arch bridge proximate a medial side of the shoe is inclined upwardly in a direction toward a front of the shoe. 250. The shoe of claim 239, further including at least one wall integral with the arch bridge proximate at least one of a medial side of the shoe and a lateral side of the shoe and extending in an upwardly direction from the arch bridge, the at least one wall of the arch bridge being visible at least in part from outside the shoe. 251. The shoe of claim 239, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 252. The shoe of claim 239, further including a flexible plate having an upper surface, a lower surface, an interior portion and peripheral portions and positioned between at least a portion of the bottom of the shoe and at least a portion of the heel region of the upper, the plate being in contact with at least a portion of the heel support. 253. The shoe of claim 127, wherein the upper includes an open interior, further including at least one opening extending in an upwardly direction from the bottom of the shoe the at least one opening being in air communication with the open interior of the upper. 254. A shoe comprising: a bottom, a medial side and a lateral side; an upper having a forward region, an arch region and a heel region; a rear sole below at least a portion of the heel region of the upper, the rear sole including a midsole material, the rear sole having a bottom surface formed of a material that is at least in part ground-engaging, the rear sole having a width from the medial side of the shoe to the lateral side of the shoe; a heel support integrally formed of a material different from the material of the ground-engaging surface of the rear sole, the heel support having a top, a bottom, a medial side, a lateral side and a rear, at least a portion of the medial side, the lateral side and the rear of the heel support being in air communication with and visible from the outside of the shoe, the heel support including a rim proximate the top of the heel support extending inwardly at least in part from at least a portion of one of the medial side, the lateral side and the rear of the heel support to define an opening in the top of the heel support, the opening having a dimension along the width of the rear sole that is greater than one-quarter the width of the rear sole, the rim having a lower surface oriented toward at least a portion of the bottom of the shoe, the heel support having a portion proximate the bottom of the heel support that extends inwardly at least in part from each of the medial side, the lateral side and the rear of the heel support, the inwardly extending portion of the bottom of the heel support having an upper surface spaced apart from and substantially parallel with the lower surface of the rim, the heel support including at least one window in at least one of the medial side, the lateral side and the rear of the heel support, at least a portion of the midsole material of the rear sole being in air communication with and visible from the outside of the shoe through the at least one window. 255. The shoe of claim 254, further including a substantially air-tight enclosure located at least in part between a portion of the upper and a portion of the bottom of the shoe, the air-tight enclosure having a top, a bottom and a vertical central axis passing through the top and the bottom of the air-tight enclosure. 256. The shoe of claim 254, wherein the shoe has a forward sole that includes an air-tight enclosure. 257. The shoe of claim 255, wherein a portion of the air-tight enclosure is at least in part curved. 258. The shoe of claim 257, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 259. The shoe of claim 257, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially parallel with the vertical central axis of the air-tight enclosure. 260. The shoe of claim 257, wherein the at least in part curved portion of the air-tight enclosure is curved in a direction substantially parallel with the vertical central axis of the air-tight enclosure and in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 261. The shoe of claim 257, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 262. The shoe of claim 257, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially parallel with the vertical central axis of the air-tight enclosure. 263. The shoe of claim 257, wherein the at least in part curved portion of the air-tight enclosure is arcuate in shape in a direction substantially parallel with the vertical central axis of the air-tight enclosure and in a direction substantially perpendicular to the vertical central axis of the air-tight enclosure. 264. The shoe of claim 255, wherein at least one of the top and the bottom of the air-tight enclosure has a portion that is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 265. The shoe of claim 255, wherein each of the top and the bottom of the air-tight enclosure has a portion that is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 266. The shoe of claim 255, wherein at least a portion of the bottom of the air-tight enclosure is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 267. The shoe of claim 255, wherein at least a portion of the top of the air-tight enclosure is generally flat and perpendicular to the vertical central axis of the air-tight enclosure. 268. (canceled) 269. The shoe of claim 255, wherein the air-tight enclosure has at least one exterior portion that is in air communication with and visible from the outside of the shoe. 270. The shoe of claim 254, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 271. The shoe of claim 254, wherein the shoe has a forward sole that includes an inflated cushion. 272. The shoe of claim 270, wherein the inflated cushion includes a bladder. 273. The shoe of claim 272, wherein the bladder is an air bladder. 274. The shoe of claim 270, wherein a portion of the inflated cushion is at least in part curved. 275. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 276. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially parallel to the vertical central axis of the inflated cushion. 277. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion is curved in a direction substantially parallel with the vertical central axis of the inflated cushion and in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 278. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 279. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially parallel with the vertical central axis of the inflated cushion. 280. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion is arcuate in shape in a direction substantially parallel with the vertical central axis of the inflated cushion and in a direction substantially perpendicular to the vertical central axis of the inflated cushion. 281. The shoe of claim 270, wherein at least one of the top and the bottom of the inflated cushion has a portion that is generally flat and perpendicular to the vertical central axis of the inflated cushion. 282. The shoe of claim 270, wherein each of the top and the bottom of the inflated cushion has a portion that is generally flat and perpendicular to the vertical central axis of the inflated cushion. 283. The shoe of claim 270, wherein at least a portion of the bottom of the inflated cushion is generally flat and perpendicular to the vertical central axis of the inflated cushion. 284. The shoe of claim 270, wherein at least a portion of the top of the inflated cushion is generally flat and perpendicular to the vertical central axis of the inflated cushion. 285. (canceled) 286. The shoe of claim 270, wherein the inflated cushion has at least one exterior portion that is in air communication with and visible from the outside of the shoe. 287. The shoe of claim 286, wherein the at least one exterior portion of the inflated cushion spans a major longitudinal axis of the shoe from a medial side of the major longitudinal axis of the shoe to a lateral side of the major longitudinal axis of the shoe. 288. The shoe of claim 270, wherein at least a portion of the inflated cushion is located in a forward portion of the rear sole and spans from a point on the medial side of the shoe to a point on the lateral side of the shoe. 289. The shoe of claim 270, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the inflated cushion completely surrounding the vertical central axis of the rear sole in a plane substantially perpendicular to the vertical central axis of the rear sole. 290. The shoe of claim 254, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the vertical central axis of the rear sole being completely surrounded by at least one inflated cushion in a plane perpendicular to the vertical central axis of the rear sole. 291. The shoe of claim 254, wherein the rear sole includes only one inflated cushion. 292. The shoe of claim 291, wherein the inflated cushion includes only one chamber. 293. The shoe of claim 292, wherein the chamber is located entirely within the rear sole. 294. The shoe of claim 291, wherein the shoe has a forward sole that includes at least one inflated cushion. 295. The shoe of claim 291, wherein the shoe has a forward sole that includes a plurality of inflated cushions. 296. The shoe of claim 270, wherein the shoe includes a major longitudinal axis and the rear sole has a vertical central axis passing through the bottom of the shoe and the heel region of the upper, the vertical central axis of the rear sole being perpendicular to the major longitudinal axis of the shoe, the vertical central axis of the inflated cushion being coincident with the vertical central axis of the rear sole. 297. The shoe of claim 270, wherein the inflated cushion has at least one sidewall that is in air communication with and visible from the outside of the shoe, the at least one sidewall being curved along a majority of the distance between the top and the bottom of the inflated cushion. 298. The shoe of claim 297, wherein the at least one sidewall has a generally uniform thickness. 299. The shoe of claim 270, wherein at least a portion of the inflated cushion is located proximate the lateral side of the shoe, at least a portion of the inflated cushion is located proximate the medial side of the shoe and at least a portion of the inflated cushion is located proximate a rear of the shoe, the portions being in communication with one another. 300. The shoe of claim 274, wherein the at least in part curved portion of the inflated cushion has the shape of an arc of a circle. 301. The shoe of claim 270, wherein the inflated cushion has an interior chamber with a height parallel to the vertical central axis of the inflated cushion, the interior chamber having a maximum cross sectional dimension perpendicular to the vertical central axis of the inflated cushion that is greater than the height of the interior chamber. 302. The shoe of claim 270, wherein the rear sole includes a layer of outsole material that forms the ground engaging surface of the rear sole, each of the inflated cushion, the inwardly extending portion of the bottom of the heel support and the layer having a portion proximate the rear of the shoe that is curved in a plane perpendicular to the vertical central axis of the inflated cushion from the medial side of the shoe to the lateral side of the shoe, the shape of the curve of each of the rear portions of the inflated cushion, the inwardly extending portion and the layer being substantially the same. 303. (canceled) 304. The shoe of claim 302, wherein the curve of each of the rear portions of the inflated cushion, the inwardly extending portion of the bottom of the heel support and the layer of outsole material is substantially semi-circular. 305. The shoe of claim 254, wherein the heel support is made of a durable plastic material. 306. The shoe of claim 254, wherein the at least one window generally forms the shape of a quadrilateral. 307. The shoe of claim 254, further including at least a second window on at least one of the medial side, the lateral side and the rear of the heel support. 308. The shoe of claim 307, wherein two of the windows are directly opposite one another. 309. The shoe of claim 254, including at least one window in the medial side, at least one window in the lateral side and at least one window in the rear of the heel support. 310. The shoe of claim 309, wherein two of the windows are directly opposite one another. 311. The shoe of claim 254, wherein the at least one window includes a plurality of windows, at least two of the windows being located on the medial side of the heel support and at least two of the windows being located on the lateral side of the heel support. 312. The shoe of claim 254, wherein at least one of the at least one window is located on a rear of the shoe. 313. The shoe of claim 254, wherein the at least one window includes at least three windows. 314. The shoe of claim 254, wherein the at least one window includes at least four windows. 315. The shoe of claim 254, wherein the at least one window includes at least five windows. 316. The shoe of claim 254, wherein the at least one window includes at least six windows. 317. The shoe of claim 254, wherein the shoe includes a major longitudinal axis, the rear sole having a vertical central axis perpendicular to the major longitudinal axis of the shoe and passing through the bottom of the shoe and the heel region of the upper, the rim including an upper surface opposite the lower surface and an interior edge connecting the upper and lower surfaces of the rim, the interior edge being oriented at least in part toward the vertical central axis of the rear sole. 318. The shoe of claim 254, wherein the heel support includes a portion extending upwardly from the rim on at least one of the medial side of the shoe, the lateral side of the shoe and a rear of the shoe. 319. The shoe of claim 254, wherein the heel support includes a portion extending upwardly from the rim on each of the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 320. The shoe of claim 318, wherein the upwardly extending portion above the rim is in air communication with and visible from the outside of the shoe. 321. The shoe of claim 318, wherein the upwardly extending portion above the rim is in air communication with and visible from the outside of the shoe from the medial side of the shoe, the lateral side of the shoe and the rear of the shoe. 322. The shoe of claim 254, wherein the lower surface of the rim, the wall and the upper surface of the inwardly extending portion of the bottom of the heel support form a recess for receiving a portion of the midsole of the shoe. 323. The shoe of claim 254, wherein the opening in the top of the heel support has a dimension along the width of the rear sole that is greater than one-half the width of the rear sole. 324. The shoe of claim 254, wherein the heel support completely separates a material forming a portion of the forward sole from the ground-engaging surface of the rear sole. 325. The shoe of claim 254, wherein at least a portion of the ground-engaging surfaces of the forward sole and the rear sole are made of a rubber material. 326. The shoe of claim 254, wherein the ground-engaging surface of the rear sole includes an opening therein that exposes a plastic material, the plastic material being visible from the bottom of the shoe. 327. The shoe of claim 254, wherein the bottom surface of the rear sole has a perimeter and a center located beneath the approximate center of the calcaneus of the wearer of the shoe, the rear sole further including a rearward portion and an opposite forward portion below the heel region of the upper, the bottom surface having at least two portions which are beveled in different directions away from the center of the rear sole, each of the beveled portions defining at least in part the perimeter of the rear sole. 328. The shoe of claim 327, wherein one of the at least two beveled portions is located at least in part in the forward portion of the rear sole and is oriented at least in part toward a front of the shoe. 329. The shoe of claim 327, wherein one of the at least two beveled portions is located at least in part in the rearward portion of the rear sole and is oriented at least in part toward the rear of the shoe. 330. The shoe of claim 327, wherein one of the at least two beveled portions is located at least in part in the forward portion of the rear sole and is oriented at least in part toward a front of the shoe and one of the at least two beveled portions is located at least in part in the rearward portion of the rear sole and is oriented at least in part toward the rear of the shoe. 331. The shoe of claim 254, wherein the rear sole has a perimeter, a rearward portion and an opposite forward portion below the heel region, the bottom surface of the rear sole including at least one substantially planar portion and at least two portions non-planar with the at least one substantially planar portion, the non-planar portions being positioned proximate the perimeter of the rear sole and separated from each other by other portions of the bottom surface of the rear sole, each of the non-planar portions being inclined upwardly from another portion of the bottom surface of the rear sole in a direction toward the perimeter of the rear sole, one of the at least two non-planar portions being proximate the rearward portion of the rear sole, and at least a portion of another of the at least two non-planar portions being proximate the forward portion of the rear sole. 332. The shoe of claim 254, further including an arch bridge positioned below at least a portion of the arch region of the upper, the arch bridge including a lower surface having an elevated portion that is non-ground-engaging, the elevated portion of the lower surface of the arch bridge being visible from outside of the shoe. 333. The shoe of claim 332, wherein the elevated portion of the lower surface of the arch bridge is visible from the bottom of the shoe. 334. The shoe of claim 332, wherein the arch bridge comprises at least a portion of the bottom of the shoe. 335. The shoe of claim 332, wherein the arch bridge is integrally formed with the heel support. 336. The shoe of claim 332, wherein the arch bridge is formed of the same material as the heel support. 337. The shoe of claim 332, wherein the arch bridge and the heel support are molded as a one-piece construction. 338. The shoe of claim 332, wherein the elevated portion of the lower surface of the arch bridge extends from the medial side of the shoe to the lateral side of the shoe. 339. The shoe of claim 332, wherein the elevated portion of the lower surface of the arch bridge extends below at least a substantial portion of the arch region of the upper. 340. The shoe of claim 332, wherein the elevated portion of the lower surface of the arch bridge extends below substantially the entire arch region of the upper. 341. The shoe of claim 332, wherein at least a forward portion of the elevated portion of the lower surface of the arch bridge proximate the medial side of the shoe is inclined upwardly in a direction toward a rear of the shoe. 342. The shoe of claim 332, wherein at least a rearward portion of the elevated portion of the lower surface of the arch bridge proximate the medial side of the shoe is inclined upwardly in a direction toward a front of the shoe. 343. The shoe of claim 332, further including at least one wall integral with the arch bridge proximate at least one of the medial side of the shoe and the lateral side of the shoe and extending in an upwardly direction from the arch bridge, the at least one wall of the arch bridge being visible at least in part from outside the shoe. 344. The shoe of claim 332, further including an inflated cushion located at least in part between a portion of the upper and a portion of the bottom of the shoe, the inflated cushion having a top, a bottom and a vertical central axis passing through the top and the bottom of the inflated cushion. 345. The shoe of claim 254, wherein the upper includes an open interior, further including at least one opening extending in an upwardly direction from the bottom of the shoe, the at least one opening being in air communication with the open interior of the upper.
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BACKGROUND OF THE INVENTION This is a continuation of application Ser. No. 10/447,003, filed May 28, 2003; which is a continuation of application Ser. No. 10/007,535, filed Dec. 4, 2001, now U.S. Pat. No. 6,604,300; which is a continuation of application Ser. No. 09/641,148, filed Aug. 17, 2000, now U.S. Pat. No. 6,324,772; which is a continuation of application Ser. No. 09/512,433, filed Feb. 25, 2000, now U.S. Pat. No. 6,195,916; which is a continuation of application Ser. No. 09/313,667, filed May 18, 1999, now U.S. Pat. No. 6,050,002; which is a continuation of application Ser. No. 08/723,857, filed Sep. 30, 1996, now U.S. Pat. No. 5,918,384; which is a CIP of Ser. No. 08/291,945, filed Aug. 17, 1994, now U.S. Pat. No. 5,560,126; all of which are incorporated herein by reference. FIELD OF THE INVENTION The present invention relates generally to an improved rear sole for footwear and, more particularly, to a rear sole for an athletic shoe with an extended and more versatile life and better performance in terms of cushioning and spring. DESCRIPTION OF PRIOR ART Athletic shoes, such as those designed for running, tennis, basketball, cross-training, hiking, walking, and other forms of exercise, typically include a laminated sole attached to a soft and pliable upper. The laminated sole generally includes a resilient rubber outsole attached to a more resilient midsole usually made of polyurethane, ethylene vinyl acetate (EVA), or a rubber compound. When laminated, the sole is attached to the upper as a one-piece structure, with the rear sole being integral with the forward sole. One of the principal problems associated with athletic shoes is outsole wear. A user rarely has a choice of running surfaces, and asphalt and other abrasive surfaces take a tremendous toll on the outsole. This problem is exacerbated by the fact that most pronounced outsole wear, on running shoes in particular, occurs principally in two places: the outer periphery of the heel and the ball of the foot, with peripheral heel wear being, by far, a more acute problem. In fact, the heel typically wears out much faster than the rest of a running shoe, thus requiring replacement of the entire shoe even though the bulk of the shoe is still in satisfactory condition. Midsole compression, particularly in the case of athletic shoes, is another acute problem. As previously noted, the midsole is generally made of a resilient material to provide cushioning for the user. However, after repeated use, the midsole becomes compressed due to the large forces exerted on it, thereby causing it to lose its cushioning effect. Midsole compression is the worst in the heel area, including the area directly under the user's heel bone and the area directly above the peripheral outsole wear spot. Despite technological advancements in recent years in midsole design and construction, the benefits of such advancements can still be largely negated, particularly in the heel area, by two months of regular use. The problems become costly for the user since athletic shoes are becoming more expensive each year, with some top-of-the-line models priced at over $150.00 a pair. By contrast, with dress shoes, whose heels can be replaced at nominal cost over and over again, the heel area (midsole and outsole) of conventional athletic shoes cannot be. To date, there is nothing in the art that successfully addresses the problem of midsole compression in athletic shoes, and this problem remains especially severe in the heel area of such shoes. Another problem is that purchasers of conventional athletic shoes cannot customize the cushioning or spring in the heel of a shoe to their own body weight, personal preference, or need. They are “stuck” with whatever a manufacturer happens to provide in their shoe size. Finally, there appear to be relatively few, if any, footwear options available to those persons suffering from foot or leg irregularities, foot or leg injuries, and legs of different lengths, among other things, where there is a need for the left and right rear soles to be of a different height and/or different cushioning or spring properties. Presently, such options appear to include only custom-made shoes that are prohibitively expensive and rendered useless if the person's condition improves or deteriorates. SUMMARY OF THE INVENTION The present invention is directed to a shoe that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the shoes and shoe systems particularly pointed out in the written description and claims, as well as the appended drawings. To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the shoe includes an upper having a heel region, a rear sole secured below the heel region of the upper, and a rear sole support attached to the upper and configured to secure the rear sole below the heel region of the upper. The rear sole support includes a flexible region positioned below the heel region of the upper and above a portion of the rear sole. The flexible region is sufficiently stiff to support a user while still being sufficiently flexible to flex and spring when the user runs or walks vigorously. The flexible region has an interior portion which in its normal, unflexed state is spaced upwardly from the portion of the rear sole immediately below said interior portion, the interior portion being adapted to flex in a direction substantially perpendicular to the major longitudinal axis of the shoe as it is used. The interior portion of the flexible region preferably is elevated relative to its peripheral portion in a direction toward the heel region of the upper. In certain embodiments the flexible region is an integral part of the rear sole support. The rear sole support may include an integral arch extension extending below the upper from a position proximate the heel region of the upper through a substantial portion of the arch region of the upper to support the arch region. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of an embodiment of the shoe of the present invention. FIG. 2 is an exploded isometric view of a rear sole support, flexible member, and rear sole for the shoe of FIG. 1. FIG. 3 is an exploded isometric view of another embodiment of a rear sole support, flexible member, and rear sole for use in the shoe of the present invention. FIGS. 4-18 are isometric views of exemplary flexible member embodiments for use in the shoe of the present invention. FIG. 19 is an isometric view of another embodiment of a rear sole support for use in the shoe of the present invention. FIG. 20 is an isometric view of another embodiment of the shoe of the present invention. FIGS. 21 and 22 are isometric views of a rear sole support for the shoe of FIG. 20. FIG. 23 is an isometric view of another embodiment of the shoe of the present invention. FIG. 24 is an isometric view of a rear sole support for the shoe of FIG. 23. FIG. 25 is a side elevation view of a securing member for use in the shoe of the present invention. FIG. 26 is a partial cut-away isometric view of the securing member of FIG. 25. FIG. 27 is an exploded isometric view of an embodiment of the shoe of the present invention. FIG. 28 is an isometric view of another embodiment of the shoe of the present invention. FIG. 29 is an exploded isometric view of a heel support and rear sole for the shoe of FIG. 28. FIG. 30 is another exploded isometric view of the heel support and rear sole of FIG. 29. FIG. 31 is a side elevation view of the rear sole of FIG. 30. FIG. 32 is a side elevation view of another rear sole that can be used in the embodiment shown in FIG. 30. FIG. 33 is an exploded isometric view of a heel support, graphite insert, and rear sole for use in the shoe of the present invention. FIG. 34 is an exploded isometric view of another embodiment of a heel support, graphite insert, and rear sole for use in the shoe of the present invention. FIGS. 35-37 are views of a rear sole for use in the shoe of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts. FIG. 1 illustrates a first embodiment of the shoe of the present invention. The shoe, designated generally as 100, has a shoe upper 120, rear sole support 140, a rear sole 150, and a forward sole 160. Shoe 100 also preferably includes a flexible member 200 (FIG. 2) positioned between rear sole 150 and a heel region of upper 120. The flexible member provides spring to the user's gait cycle upon heel strike and reduces or eliminates interior rear midsole compression in that it is more durable than conventional midsole material. Upper 120 may be composed of a soft, pliable material that covers the top and sides of the user's foot during use. Leather, nylon, and other synthetics are examples of the various types of materials known in the art for shoe uppers. The particular construction of the upper is not critical to the shoe of the present invention. It may even be constructed as a sandal or may be made of molded plastic, integral with the rear sole support, as in the case of ski boots or roller blade uppers. Forward sole 160 is attached to upper 120 in a conventional manner, typically by injection molding, stitching, or gluing. Forward sole 160 typically includes two layers: an elastomeric midsole laminated to an abrasion-resistant outsole. The particular construction of the forward sole is not critical to the invention and various configurations may be used. For example, the midsole may be composed of material such as polyurethane or ethylene vinyl acetate (EVA) and may include air bladders or gel-filled tubes encased therein, and the outsole may be composed of, by means of example only, an abrasion-resistant rubber compound. Rear sole support 140 is also attached to the heel region of upper 120 in a conventional manner, such as injection molding, stitching, or gluing. Rear sole support 140 is substantially rigid and is configured to stabilize the heel region of upper 120 and secure rear sole 150 below the heel region. As shown in FIG. 2, rear sole support 140 may include an upwardly extending wall 142, referred to as a heel counter, that surrounds the periphery of the heel region of upper 120 to provide lateral stabilization. Wall 142 preferably surrounds the rear and sides of upper 120 proximate the heel region and in service supports and stabilizes the user's heel as he or she runs. Rear sole support 140 also includes a downwardly extending side wall 144 that defines a recess 146 sized to receive a portion of rear sole 150, preferably a rear sole which is removable and rotatable to several predetermined positions. Wall 144 shown in FIG. 2 is generally circular and securely contains and holds rear sole 150. A plurality of openings 145 is formed in wall 144 to facilitate securement of rear sole 150 to rear sole support 140. The components of rear sole support 140 are preferably made integral through injection molding or other conventional techniques and are preferably composed of plastic, such as a durable plastic manufactured under the name PEBAX. It is further contemplated that the rear sole support can be made from a variety of materials, including without limitation other injection-molded thermoplastic engineering resins. As shown in FIGS. 1 and 2, rear sole support 140 may include an arch extension or support 180 to provide a firm support for the arch of the foot and to alleviate potential gapping problems where sole support wall 144 would be adjacent forward sole 160. Arch extension 180 generally extends below upper 120 from the forward portion of side wall 144, through the arch region. It may extend as far as the ball of the foot. It is attached to upper 120 and forward sole 160 by gluing or other conventional methods. Arch extension 180 may be composed of the same material as the rear sole support and made integral with rear sole support 140 by injection molding. Alternatively, it may be made of the same or a different stiff but flexible material (such as carbon or fiberglass ribbons in a resin binder) and glued to rear sole support 140. Such one-piece construction of the arch extension together with the rear sole support solves another major problem, namely the tendency of an athletic shoe of conventional resilient material in the arch area to curl at the juncture of the substantially rigid rear sole support with the resilient forward sole. Shoe 100 also includes a rear sole 150 that is detachably secured to and/or rotatably positionable relative to rear sole support 140. Rear sole 150, as shown in FIG. 1, includes a rubber ground-engaging outsole 154 containing a planar area and three beveled segments or portions that soften heel strike during use. As shown, the beveled segments or portions formed on the outsole have the same shape and configuration and are positioned symmetrically about the periphery of the outside and preferably symmetrically positioned about the center of rear sole 150. As explained in more detail, rear sole 150 and the attachment features that permit rear sole 150 to be placed and locked into different positions relative to rear sole support 140 are designed and configured so that one symmetrically located beveled portion can be moved into the position previously occupied by another beveled portion. As a result, as one of the beveled portions begins to wear, rear sole 150 can be repositioned to place an unworn beveled portion in the area of the shoe where there is greater wear for a particular user. By periodically altering the position of the sole before any beveled portion is badly worn, (or any midsole material directly above the bevel is badly compressed) the life and effectiveness of the rear sole, and the entire shoe, can be significantly increased. Moreover, after a given rear sole wears beyond its point of usefulness, it can be replaced with a new sole with the same or different characteristics. Prior to replacement, it is also possible that left and right rear soles may be exchanged with each other inasmuch as left and right rear soles often exhibit opposite wear patterns. As shown in FIG. 2, rear sole 150 also includes a midsole 158 laminated to outsole 154. Midsole 158 includes a substantially cylindrical lower portion 162 and a substantially cylindrical upper portion 164 that is smaller in diameter than lower portion 162. Upper portion 164 includes a plurality of resilient knobs 165 that mate with openings 145 in rear sole support 140. As shown, the resilient knobs 165 and openings 145 are symmetrically positioned about the central axis of midsole 158 and the recess of rear sole support 140, respectively. To secure rear sole 150 to rear sole support 140, rear sole 150 is simply press-fitted into recess 146 until knobs 165 engage corresponding openings 145. This manner of locking rear sole 150 into the shoe at any one of several positions is one of several mechanical ways in which the rear sole can be removed, repositioned, and/or locked to the rear sole support or other part of a shoe. In the embodiment shown in FIG. 2, upper midsole portion 164 has a diameter at least equal to and preferably slightly larger than that of the recess into which it fits. Midsole portion 162 has a diameter substantially equal to the diameter defined by the exterior portion of circular wall 144. This configuration of elements eliminates any vertical gapping problems from occurring between the wall of the rear sole support and the peripheral surface of the rear sole. The inside diameter of a circular recess 146, as measured between the inside surfaces of its sidewalls, or the distance between the inside surface of a medial sidewall and the inside surface of an opposite lateral sidewall in the case of a non-circular recess (not shown), may actually be greater than the width of the heel region of the shoe upper as measured from the exterior surface of the medial side of the heel region of the upper to the exterior surface of the lateral side of the heel region of the upper (i.e., the heel region of the upper at its widest point). This is possible because the material used to make the rear sole support 140 and side walls is sufficiently strong and durable to permit the side walls to “flare out” to a greater width than the heel region of the upper without risk of breakage. This in turn permits the use of a larger rear sole 150 with more ground-engaging surface and, hence, more stability. (As stated, the exterior walls of the lower portion of the rear sole generally align vertically with the exterior surface of the side walls forming the recess 146). It also permits the employment of a flexible region or member with a correspondingly larger diameter, width or length because its peripheral edges optimally should align vertically with the load-bearing side walls of the recess. Such a larger flexible region or member, with a diameter, width or length greater than the width of the heel region of the upper at its widest point, creates more cushioning and/or spring for the user's heel during the gait cycle. The observations and provisions contained in this paragraph are equally applicable to the embodiments described in FIGS. 1, 2, and 3. Rear sole 150 is preferably made from two different materials: an abrasion-resistant rubber compound for ground-engaging outsole 154; and a softer, more elastomeric material such as polyurethane or ethylene vinyl acetate (EVA) for midsole 158. However, rear sole 150 could be comprised of a single homogenous material, or two materials (e.g., EVA enveloped by hard rubber), as well as a material comprising air encapsulating tubes, for example, disclosed in U.S. Pat. No. 5,005,300. For each of the discussed rear sole embodiments, the outsole and midsole materials are preferably more resilient than materials used for the rear sole support or arch extension. Detachability of rear sole 150 allows the user to change rear soles entirely when either the sole is worn to a significant degree or the user desires a different sole for desired performance characteristics for specific athletic endeavors or playing surfaces. The user can rotate the rear sole to relocate a worn section to a less critical area of the sole, and eventually replace the rear sole altogether when the sole is excessively worn. By periodically changing the position of the rear sole, more uniform wear and long life (both outsole and midsole) can be achieved. Additional longevity in wear may also be achieved by interchanging removable rear soles as between the right and left shoes, which typically exhibit opposite wear patterns. In addition, some users will prefer to change the rear soles not because of adverse wear patterns, but because of a desire for different performance characteristics or playing surfaces. For example, it is contemplated that a person using this invention in a shoe marketed as a “cross-trainer” may desire one type of rear sole for one sport, such as basketball, and another type of rear sole for another, such as running. A basketball player might require a harder and firmer rear sole for stability where quick, lateral movement is essential, whereas a runner or jogger might tend to favor increased shock absorption features achievable from a softer, more cushioned heel. Similarly, a jogger planning a run outside on rough asphalt or cement might prefer a more resilient rear sole than the type that would be suitable to run on an already resilient indoor wooden track. Rear sole performance may also depend on the weight of the user or the amount or type of cushioning desired. The present invention includes a shoe or shoe kit which includes or can accept a plurality of rear soles 150 having different characteristics and/or surface configurations, thereby providing a cross trainer shoe. As explained in more detail below, the shoe can also be designed to accept and use different flexible members in the rear sole area, to achieve optimal flex and cushioning, through the combination of a flexible member and rear sole selected to provide the most desirable flex, cushion, wear, support, and traction for a given application. In a preferred embodiment, both the rear sole and the flexible member are replaceable and a given rear sole can be locked in a plurality of separate positions relative to the recess in which it is held. Since rear sole 150 shown in FIGS. 1 and 2 is selectively positionable relative to rear sole support 140 in a single plane about an axis perpendicular to the major longitudinal axis of the shoe, it may be moved to a plurality of positions with a means provided to allow the user to secure the rear sole at each desired position. After a period of use, outsole 154 will exhibit a wear pattern at the point in which the heel first contacts the ground, when the user is running, for example. Excessive wear normally occurs at this point, and at midsole 158 generally above this point, degrading the performance of the rear sole. When the user determines that the wear in this area is significant, the user can rotate the rear sole so that the worn portion will no longer be in the location of the user's first heel strike. For the shoe shown in FIGS. 1 and 2, rotation is accomplished by detaching the rear sole and reattaching at the desired location. For the embodiment in FIG. 3 discussed below, the rear sole may be rotated without separating it from the rear sole support. The number of positions into which rear sole of FIGS. 1 and 2 can be rotated is limited by the number of knobs/openings, but is unlimited for the rear sole shown in FIG. 3. The use of other mechanical locking systems to allow selective movement and locking of the rear sole is contemplated within the spirit of the invention. Rotating the rear sole about an axis normal to the shoe's major axis to a position, for example, 180 degrees beyond its starting point, will locate the worn portion of the rear sole at or near the instep portion of the shoe. The instep portion is an area of less importance for tractioning, stability, cushioning and shock absorbing purposes. As long as the worn portion of the rear sole is rotated beyond the area of the initial heel strike, prolonged use of the rear sole is possible. The user can continue periodically to rotate the rear sole so that an unworn portion of the rear sole is located in the area of the first heel strike. The shape of rear sole can be circular, polygonal, elliptical, “sand-dollar,” elongated “sand-dollar,” or otherwise. The shape of recess 146 is formed to be compatible with the shape of the rear sole. In all embodiments, the invention includes mechanical means for selectively locking the rear sole relative to the rear sole support and upper of the shoe. Preferably, the rear sole is shaped so that at least the rear edge of the outsole has a substantially identical profile at several, or preferably each rotated position. To allow for a plurality of rotatable positions, the shape of the outsole preferably should be symmetrical about its central axis. As shown in FIG. 1, the rear sole has three beveled portions which are symmetrically positioned about its central axis. The user in this embodiment can rotate the rear sole 120.degree. and place an unworn beveled portion at the rear heel region of the shoe, where wear is often maximum. Alternatively, the rear sole could have two beveled portions, 180.degree. apart (in an oval embodiment this would have to be the case), in which event only one rotation per shoe, plus an exchange between right and left rear soles, would be possible, before replacement of rear soles would be necessary. While the above discussion is directed towards a rear sole that rotates or separates in its entirety, it is specifically contemplated that the same benefits of this invention can be achieved if only a portion of the rear sole is rotatable or removable. For example, a portion of the rear sole, e.g., the center area, may remain stationary while the periphery of the ground-engaging surface or outsole rotates and/or is detachable. As another example, the rear sole may not be removable but only rotatably positionable. In a preferred embodiment of the invention, the shoe of the present invention includes a flexible region 200 that is positioned above the rear sole and has a central portion that in its normal unflexed state is spaced upwardly from the portion of the shoe (rear sole support, or rear sole) immediately below it. The flexible region 200 is designed to provide a preselected degree of flex, cushioning, and spring, to thereby reduce or eliminate heel-center midsole compression found in conventional materials. Flexible region 200 is made of stiff, but flexible, material. Examples of materials that may be used in the manufacture of flexible member 200 include the following: graphite; fiberglass; graphite (carbon) fibers set in a resin (i.e. acrylic resin) binder; fiberglass fibers set in a resin (i.e. acrylic resin) binder; a combination of graphite (carbon) fibers and fiberglass fibers set in a resin (i.e. acrylic resin) binder; nylon; glass-filled nylon; epoxy; polypropylene; polyethylene; acrylonitrile butadiene styrene (ABS); other types of injection-molded thermoplastic engineering resins; spring steel; and stainless spring steel. The flexible region 200 can be incorporated into other elements of the shoe or can be a separate flexible member or plate. As shown in FIG. 2, flexible member 200 can be in the form of a plate supported at its peripheral region by an upward facing top surface of rear sole support 140. In this embodiment, the member or plate 200 is positioned between the rear sole 150 and the heel portion of upper 120. A ledge 148 may be formed in rear sole support 140 to support and laterally stabilize flexible member 200. The flexible member may also be permanently attached to the top or bottom of the rear sole support or detachably secured to the shoe upper and removable through a pocket formed in the material (not shown) typically located on the bottom surface of the upper, or it can be exposed and removed after removing the sock liner or after lifting the rear portion of the sock liner. Alternatively, it may be totally exposed as in the case of flexible member 200 shown in FIG. 18, wherein the U-shaped cushioning member may have direct contact with the user's heel without an intervening sock liner in the heel portion of the shoe. The removability of the flexible member allows the use of several different types of flexible members of varying stiffness or composition and, therefore, can be adapted according to the weight of the runner, the ability of the runner, the type of exercise involved, or the amount of cushioning and/or spring desired in the heel of the shoe. Rear sole 150 may have a concave top surface 167, as shown in FIG. 2. Therefore, when the rear sole is attached to the rear sole support, the top surface of the rear sole does not come into contact with the flexible member when the flexible member deflects within its designed range of flex. As a result, the middle of the flexible member can flex under the weight of the user without being impeded by rear sole 150. Flexible member 200 thus acts like a trampoline to provide extra spring in the user's gait in addition to minimizing, or preventing, midsole compression in the central portion of the rear sole. A second preferred embodiment is shown in FIG. 3. In this embodiment, a rear sole 250 is identical to rear sole 150 shown in FIG. 2 except that it has a groove 254 below upper midsole portion 252, instead of knobs 165. A rear sole support 240 includes a downwardly extending wall 244 that has a serrated bottom edge 246 and a threaded inner surface 248. Rear sole support 240 also includes an upper rim 249. The embodiment of FIG. 3 also indicates a threaded ring 400. Ring 400 includes a threaded outer surface 410 that mates with threaded inner surface 248 of rear sole support 240. The ring also includes an outwardly and inwardly extending flange 412 that presses against serrated bottom edge 246 when the ring is screwed into the rear sole support. The bottom surface of flange 412 includes anchors 414, and may also be serrated to further grip the rear sole to prevent rotation. The ring also has two ends 416 and 418, and end 416 may have a male member and end 418 may be shaped to receive the male member to lock the two ends together. Ring 400 may be made of hard plastic or other substantially rigid materials that provide a secure engagement with rear sole support 240 and a firm foundation for supporting flexible member 200. Rear sole 250 is attached to rear sole support 240 by unlocking the ends of ring 400 and positioning ring 400 around upper midsole portion 252 of the rear sole such that flange 412 engages groove 254. Ring 400 is then firmly locked onto the rear sole by mating end 416 with end 418. Flexible member 200 is inserted into the rear sole support so that it presses against upper rim 249. Ring 400, with rear sole 250 attached, is then screwed into the rear sole support by engaging threaded surface 410 of the ring with threaded surface 248 of wall 244. The ring is then screwed into the rear sole support until serrated edge 246 of wall 244 engages flange 412 of ring 400. Serrated edge 246 serves to prevent rotation of the ring during use and the top edge of ring 400 firmly supports flexible member 200. The rear sole support sidewalls need not be continuous around the entire recess. Such sidewalls may be substantially eliminated on the lateral and medial sides of the rear sole support, or even at the rear and/or front of the rear sole support, exposing ring 400 when installed, even allowing it to protrude through the sidewalls where the openings are created. This has no effect whatsoever on the thread alignment on the inside surface of the remaining sidewalls. The advantage of doing this is that a ring with a slightly larger diameter than otherwise possible and, hence, a flexible member with a slightly larger diameter than otherwise possible may be employed. In the embodiment shown in FIG. 3, a variety of different flexible members 200 having different flex and cushioning characteristics can be selectively incorporated into the shoe. Flexible member 200, once incorporated into the shoe, is securely held in place with rear sole support 240. Preferably, the rear sole support contacts flexible member 200 only along its outer periphery, and rear sole support 240 includes an opening above the flexible member, thereby permitting the plate to protrude upwardly toward the user's heel. Moreover, because the top surface of rear sole 250 is preferably concave in shape, the central portion of the rear sole does not contact the central portion of the flexible member in its unflexed, normal position. As a result, the flexible member can also flex downward. The degree of flexing of the member can be controlled both by the selection of the material and shape of the member, as well as the relative dimensions and shape of rear sole support 240 and rear sole 250. While flexible member 200 and the corresponding recess in rear sole support 240 are circular in FIG. 3, other shapes can be utilized. Rear sole support 240 could be designed to include a recess above upper rim 249 to accept the flexible member and a mechanical means, such as a circular locking ring, similar to ring 400, to support and lock the flexible member in place. In such an embodiment, the user could change the flexible member from the inside of the shoe. Similarly, the flexible member 200 could be fixedly secured to, or incorporated as an integral part, of either the rear sole support or the rear sole. Similar configurations of an integral flexible region are within the spirit of the invention. The embodiment of FIG. 3 and other embodiments of the invention preferably provide a shoe that includes a flexible region or member which has its own preselected spring and cushioning characteristic and which is preferably removable and replaceable, a rear sole with its own pre-selected cushioning properties (both outsole and midsole) and which is preferably removable, replaceable, and capable of being locked in place at a plurality of preselected positions; a plurality of beveled portions on the outer surface of the rear sole which are preferably symmetrically located about its axis; and an interrelationship of the flexible member, rear sole support, and rear sole which permit the flexible member to freely flex to at least a predetermined degree. The flexible region and its characteristics, the rear sole and its characteristics, and the rear sole's relative location to the flexible region can be selectively altered, to provide in combination an optimal shoe for a given application. Also, because of the rear sole rotation and replacement permitted by the invention, typically heavy outsole material may be made thinner than on conventional athletic shoes, thus reducing the weight of the shoe. The invention also permits the weight of the shoe to be further reduced because the central portion of the midsole of the rear sole can be eliminated, since the flexible region of the shoe provides weight bearing and cushioning at this area. Other rear sole support/rear sole combinations for securing the rear sole to the shoe and for supporting the flexible member at or below the heel region of the upper are contemplated and fall within the spirit of this invention, as described and claimed. By means of example only, some such additional configurations are disclosed in commonly-owned U.S. patent application Ser. No. 08/291,945, now U.S. Pat. No. 5,560,126, which is incorporated herein by reference. The flexible region of the present invention is not limited to a circular shape and can be adapted to conform to the shape of the rear sole. The flexible region also need not be used only in conjunction with a detachable rear sole, but can be used with permanently attached rear soles as well. FIGS. 4-17 show various alternative embodiments of the flexible member. In each of these embodiments, the flexible member may be curved or convex in shape, or have an inwardly curved or concave bottom surface, such that the interior portion of the flexible member is elevated relative to its periphery when the flexible member is positioned in the shoe in its normal position. Each of the following flexible member embodiments may be used in conjunction with the rear sole support/rear sole combinations disclosed in FIGS. 1-3 and more generally disclosed in this disclosure in its entirety. In addition, the following disclosed embodiments of flexible members can be integrally incorporated into a portion of the shoe. In either event, the resultant shoe has a flexible region which provides a preselected flex and spring. As shown in FIG. 4, flexible member 500 has a concave under surface 502 (when viewed from its bottom) and an opposing convex upper surface, and is circular in shape. As a result, the interior portion of the flexible member 500 is elevated relative to its peripheral portion and is positioned above a portion of the rear sole of the user when supported in the shoe. Flexible members 510 and 520 shown in FIGS. 5 and 6, respectively, are similar in structure to flexible member 500 except that flexible member 510 has a bottom surface 514 and a moon-shaped notch 512 and flexible member 520 has a bottom surface 524 and two opposing moon-shaped notches 522. Notch 512 of flexible member 510 is preferably aligned with the back of the rear sole. One of notches 522 of flexible member 520 may be aligned with the back of the rear sole, or alternatively such notches may be aligned with the lateral and medial sides of the shoe. Flexible member 530 as shown in FIG. 7 is identical in structure to flexible member 520 shown in FIG. 6 except that it is not spherically convex in shape, but rather convexly curved in only one direction. The flexible member 530 alignment options are the same as those of flexible member 520. As shown in FIG. 8, flexible member 540 includes a plurality of spokes 542 each joined at one end to a hub 544 and joined at an opposite end to rim 546. The size, shape, and number of spokes is variable depending on the desired flexibility. As shown in FIG. 8, each of spokes 542 has a triangular cross-section, although the cross-section may also be square, rectangular, or any other geometrical shape. When positioned in the shoe, hub 544 is elevated relative to rim 546 such that hub 544 is closer to the heel region of the upper. The flexible members shown in FIGS. 9-12 are variations of flexible member 540 shown in FIG. 8. Flexible member 550 shown in FIG. 9 is identical in structure to flexible member 540, but includes webbing 552 covering the top surface of flexible member 550 and joining each of spokes 542 to reinforce flexible member 550. Webbing 552 may be injection molded with the rest of flexible member. Flexible member 560 shown in FIG. 10 is similar in structure to flexible member 540 shown in FIG. 8; however, spokes 562 decrease in thickness between hub 564 and the central portion of each of the spokes 562 and then increase in thickness from the central portion toward rim 566. Flexible member 570, shown in FIG. 11, also includes a plurality of spokes 572 joined at opposite ends to hub 574 and rim 576. In this embodiment, the thickness of the spokes decreases in a direction from hub 574 toward rim 576. As shown in FIG. 11, the decreasing thickness of spokes 572 results in at least a portion of the interior portion of flexible member 570 in the area of the decreasing thickness spokes 572 being thinner than at least a portion of its peripheral edges or rim 576. Hub 574 and other portions of the center portion of the interior portion of flexible member 570 are shown as being thicker than another portion of the interior portion of flexible member 570, such as in the area of decreased spoke thickness. As shown in FIG. 11, center portion or hub 574 and peripheral edge or rim 576 may both be thicker than a portion of the interior portion of flexible member 570 between hub 574 and rim 576. In addition, webbing 578 may be placed over the top surface of flexible member 570 similar to that disclosed in FIG. 9. As shown in FIG. 11, spokes 572 are preferably oriented such that each spoke is oriented 180 degrees from an opposite spoke to provide a rib that extends substantially across flexible member 570. Whether referred to as opposite spokes 572 or a rib the thickness may be varied. The rib is preferable integrally formed with flexible member 570 and more preferably is on the bottom surface or concave surface of flexible member 570. As can be seen in FIG. 11, a hole may be provided through flexible member 570 and more particularly, through the center or hub 574. As can be further determined from FIG. 11, flexible member 570 may be substantially planar in shape, but is not conical in shape. FIG. 12 illustrates a housing 580 for supporting the flexible member, in this example, flexible member 560. Housing 580 has an L-shaped cross-section to support the bottom and side surfaces of rim 566. Housing 580 may be inserted into the shoe heel with flexible member 560 or may be permanently affixed to the rear sole support. In either case, housing 580 acts as a reinforcement for limiting or eliminating lateral movement of flexible member 560 during use. This may have the effect of making the center of the flexible member more springy. It may also allow the member to be made of thinner and/or lighter weight material. FIGS. 13 and 14 show further variations of flexible plate 500 shown in FIG. 4. While flexible plate 500 has a generally uniform thickness at any given radius, flexible plate 585 shown in FIG. 13 decreases in thickness from the center of the member toward its periphery. Flexible member 590 shown in FIG. 14, on the other hand, is thicker near the center and at the periphery, but thinner therebetween. FIGS. 15-17A disclose flexible members composed of carbon ribbons set in a resin binder. Alternatively, they may be fiberglass ribbons or a combination of carbon and fiberglass ribbons. Ribbons made of other types of fiber may also be used. Flexible member 600 includes radially or diametrically projecting ribbons 602, either emanating from the center of flexible member toward its periphery or, preferably, passing through the center from a point on the periphery to a diametrically opposite point on the periphery. These ribbons 602 are fixed in position by a resin binder 604 known in the art. Flexible member 610 shown in FIG. 16 also includes carbon ribbons 602 set in a resin binder 604, but further includes a rim 606 comprised of ribbon preset in the resin binder and defining the periphery of flexible member 610. Flexible member 620 shown in FIG. 17 is identical to flexible member 610 shown in FIG. 16 except that it further includes a circular ribbon 608 disposed in resin binder 604 and circumscribing the center of flexible member 620. The flexible member shown in FIG. 17A is identical to the flexible member 610 shown in FIG. 17 except that it has fewer spokes and further includes a plurality of circular ribbons 608 spaced radially from the center of the member and disposed in the resin binder 604. Flexible members 600, 610, and 620 may be convex in shape so that the center of the flexible member is raised relative to its outer perimeter, when placed in the shoe. They may also have a U-shaped cushioning member placed on or secured to their top surface like that shown in FIG. 18. Since it is contemplated that the flexible member will be composed of graphite or other stiff, but flexible, material, it is preferable to cushion the impact of the user's heel against the flexible member during use. As shown in FIG. 18, a substantially U-shaped cushioning member 650 is disposed on the top surface of flexible member 500 to cushion the heel upon impact. The U-shaped cushioning member is shaped to generally conform to the shape of the user's heel. Thus, the open end of the U-shape is oriented toward the front of the shoe. Cushioning member 650 may be composed of polyurethane or EVA or may be an air-filled or gel-filled member. Cushioning member 650 can be affixed to flexible member 500 by gluing, or may be made integral with flexible member 500 in an injection molding process. If injection molded, cushioning member 650 would be made of the same material as flexible member 500. To decrease the stiffness of cushioning member 650 in this instance, small holes (not shown) may be drilled in cushioning member 650 to weaken it and thereby allow it to depress more readily upon impact and more uniformly with flexible member 500. The cushioning member 650 described above can be incorporated into a shoe having any of the various flexible regions disclosed in this application and drawings, as well as other shoes falling within the scope of the claims. If cushioning member 650 is used, the shoe sock liner, which generally provides cushioning, may be thinner in the heel area or may terminate at the forward edge of cushioning member 650. If cushioning member 650 is not used, the sock liner may extend to the rear of the shoe and may be shaped to conform to the user's heel on its top surface and the flexible member on its bottom surface. Its bottom surface may also compensate for gaps formed by the flexible member. For example, the sock liner may have a concave bottom surface in the heel area to correspond to those flexible members having convex upper surfaces. In each of the above-described embodiments, the flexible member is illustrated as a separate component of the shoe which can be removed from the shoe and replaced by a similar or different flexible member, as desired. In each of the embodiments the central portion of the flexible member is raised relative to its outer perimeter so that when placed in the shoe, the interior portion in its normal state does not touch the rear sole support and/or rear sole. As a result, the interior of the flexible member will flex in response to the user's stride without first, if ever, contacting the rear sole support and/or rear sole. Such flexible member, therefore, can be used with rear soles that have a flat upper surface, as well as those that have a concave upper surface. The relative shape and positioning of the flexible member and the adjacent rear sole support or rear sole can be designed to provide the optimum flex, stiffness, and spring characteristics. However, each of the above-described flexible members may be made integral with the rear sole support, which not only decreases the number of loose parts and increases the efficiency of the manufacturing process, but also further limits the lateral displacement of the periphery of the flexible member upon deflection, potentially creating more spring in the center and/or permitting the use of thinner and/or lighter weight material. As shown in FIG. 19, rear sole support 340 is identical in structure to rear sole support 140 shown in FIG. 2 except that rear sole support 340 has a flexible region 700 that serves the same purpose and function as any of the above-described flexible members. In fact, any of the above-described flexible members may be used as flexible region 700 so long as they can be made integral with rear sole support 340. In this example, flexible region 700 is convex in shape and thus similar to flexible member 500 shown in FIG. 4. Cushioning member 650 or a modified sock liner as described above may also be used. The flexible region may be incorporated into other rear sole support embodiments as well. As an alternative to using arch extension 180, rear sole support 440 shown in FIGS. 20-22 includes a thickened tongue 447 that extends toward the ball of the foot. Thickened tongue 447 provides additional gluing surface for attaching the rear sole support to forward sole 160 and additional stiffness to the heel portion of the shoe and the arch area, thus minimizing the chances of separation of the forward sole from the rear sole support, and at the same time minimizing the tendency of the shoe to curl at the juncture of the hard rear sole support with the soft forward sole. Similar to rear sole support 240, rear sole support 440 includes a heel counter 442 and a side wall 444. Rear sole support 440 also includes a rim 448 and anchors 452 to receive and retain a rear sole with a mating groove, such as rear sole 250. Forward sole 260 is longer in this embodiment to extend back to the edge where it would abut the rear sole. Flexible region 710 is identical to flexible region 700 in FIG. 19. In another embodiment, rear sole support 460, as shown in FIGS. 23 and 24, includes a tongue 462 that is thinner and slightly smaller than tongue 447 shown in FIGS. 20-22. However, rear sole support 460 includes a curved wall 464 that has a pocket formed on its forward side for receiving a mating rear edge of forward sole 360 adjacent the rear sole support. Curved wall 464 provides a firm, smoothly contoured transition from hard-to-align resilient materials of the forward and rear soles and thereby minimizes gapping. It also provides a desirable brace or bumper for the lower portion of the rear sole when the user is running. Flexible region 720 is identical to flexible regions 700 and 710. As shown in FIGS. 25 and 26, the flexible member may also be integrated with the securing member. Securing member 750 is similar in structure and function as securing member 400 in that it includes a wall 752 with a threaded outer surface, an inwardly and outwardly extending rim 754, and anchors 756. Securing member 750 also includes a convex flexible region 760 integral with wall 752. Flexible region 760, like flexible regions 700 and 710, may incorporate any of the configurations shown in FIGS. 4-18. Securing member 750 is simply substituted for securing member 400 and flexible member 200 shown in FIG. 3 to attach rear sole 250 to rear sole support 240. However, since securing member 750 does not include mating ends 416, 418, rear sole 250 is press-fitted into securing member 70 until rear sole groove 254 mates with securing member rim 754. This may have the effect of making the center of the flexible member more springy. It may also allow the flexible member to be made of thinner and/or lighter weight material. FIG. 27 illustrates another embodiment of the shoe of the present invention. The shoe, designated generally as 820, has a shoe upper 822, a forward sole 824, a heel support 826, and a rear sole 828. The forward sole and heel support are attached to the shoe upper in a conventional manner, typically by injection molding, stitching or gluing. As shown in FIG. 27, the heel support 826 preferably includes a heel counter 827 for stabilizing a heel portion of the upper 22 above the heel support and a side wall 838 that extends downwardly from the upper and defines a recess 840 sized to receive the rear sole. The heel support may also include a substantially horizontal top wall 838′ for supporting the heel portion of the upper. Otherwise, the top of the rear sole or an insert, as will be discussed in more detail later, will support the heel portion of the upper. The components of the heel support, including heel counter 827 and the side wall 838, are preferably made integral through injection molding or other conventional techniques and are preferably composed of plastic, such as a durable plastic manufactured under the name PEBAX. Another embodiment of the present invention is shown in FIGS. 28-31. The shoe includes an upper 22, a heel support 940, a rear sole 950, and a forward sole 960. As shown in FIG. 29, the heel support 940 includes a heel counter 942, a downwardly extending wall 944 that defines a recess 946 sized to receive the rear sole, and a rim 948 formed around the lower portion of the wall and extending inwardly into the recess. Anchors 952 may be formed on the bottom surface of the rim 948 and extend downwardly toward the rear sole 950. The rear sole 950 includes a rubber ground-engaging surface 954 containing, in this embodiment, three beveled segments or edges 956. As shown in FIG. 31, the rear sole 950 also includes a midsole 958 laminated to the ground-engaging surface 954 that includes a substantially cylindrical lower portion 962 and a substantially cylindrical upper portion 964 that is smaller in diameter than the lower portion. A groove 966 is formed between these upper and lower portions and receives the rim 948 of the heel support to retain the rear sole in the heel support recess. The upper midsole portion 964 includes a spiral groove 968, as shown in FIGS. 29-31, that allows the rear sole to be screwed into the heel support. As shown in FIG. 29, a portion of the rim of the heel support is cut away at 970. The rear sole is screwed into the heel support by aligning the top of the spiral groove with an edge 972 of the rim adjacent the cut-away portion. A sharp instrument (such as a slender screwdriver), inserted through the window 974 and into the top of the spiral groove 968 may aid in the start-up process. The rear sole is then simply rotated, and the rim engages the spiral groove of the rear sole to screw the upper midsole of the rear sole into the recess. Once fully inserted, the rear sole may be rotated freely within the recess by hand, albeit with desired resistance. When the rear sole is attached to the heel support, the optional anchors sink into the lower midsole portion of the rear sole due to the weight of the user to prevent rotation of the rear sole during use. It should be noted that the configuration of the midsole 958, i.e., the upper midsole portion having a diameter equal to or slightly larger than that of the recess defined by the rim and a lower midsole portion having a diameter substantially equal to the diameter defined by the circular wall 944, further eliminates any vertical gapping problems from occurring between the wall of the heel support and the peripheral surface of the rear sole. To assist in removing the rear sole from the heel support, the two windows 974, 976 (FIG. 29) are formed in the wall of the heel support, a first window 974 above the cut-away portion of the rim and a second window 976 positioned 180 degrees around the wall of the heel support from the first window. In addition, a small indention 978 is formed on the peripheral surface of the upper midsole portion 964 at a position 180 degrees from the point at which the spiral groove 968 intersects the bottom of the upper midsole portion 964, as shown in FIG. 31. To remove the rear sole from the heel support, the rear sole is rotated in the heel support until the small indention appears in the second window 976. At this point, the bottom of the spiral groove is aligned with the center of the cut-away portion. The user, again using a screwdriver or similar instrument inserted through the window 974 into the spiral groove 968, can then simply rotate the rear sole so that the rim of the heel support engages the spiral groove. The rear sole is then simply rotated to screw the rear sole out of the heel support. It is not necessary to include a spiral groove in the rear sole for attaching and removing the rear sole from the heel support. As shown in FIG. 32, a rear sole 950 is similar to that shown in FIG. 31, but includes no spiral groove and no small indention. Because the upper portion 964 and lower portion 962 of the midsole 958 are made of a soft material, it can be press-fitted into the recess of the heel support until the rim 948 engages the groove 966. As shown in FIGS. 28-30, the shoe of the present invention also preferably includes an arch bridge 980 attached to, and integral with, the heel support 940 to provide an even firmer support for the arch of the foot and for alleviating potential gapping problems where the wall of the heel support is adjacent the forward sole. The arch bridge 980 generally extends from the rear of the recess 946 (where it attaches to the heel counter 942 and side wall 944) to the ball of the foot and is attached to the upper 22 and forward sole 960 by gluing or other conventional methods. The arch bridge 980 also is preferably composed of the same material as the heel support and is made integral with the heel support 940 by molding. Such one-piece construction of the arch bridge together with the heel support solves another major problem, and that is the tendency of an athletic shoe of conventional “full body” arch construction to curl at the juncture of the hard heel support with the resilient forward sole. Another embodiment for attaching the graphite insert is shown in FIG. 33. In this embodiment, the graphite insert 1000 is inserted through the bottom of the heel support 1040 so that the periphery of the graphite insert presses against the lower surface of an upper rim 1049 of the heel support. A plastic ring 1010 is also inserted in the recess between the graphite insert and the rim 1048. Such ring 1010 is flexible enough to allow it to be inserted into the heel support. The ring supports the periphery of the lower surface of the graphite insert. The rear sole 1050 is a screw-in type identical to the rear sole 950 shown in FIG. 31 except that it has a concave top surface to allow the graphite insert to flex during use. As shown in FIG. 33, the rim 1048 of the heel support includes two cut-away portions at 1070 and windows 1074, 1076 to allow the graphite insert and the ring to be inserted into the recess of the heel support, in addition to allowing the rear sole to be screwed onto the heel support in the same manner as contemplated by FIGS. 29, 30 and 31. The ring 1010 also has windows 1012, 1014 that are aligned with the windows 1074, 1076 when the ring is inserted into the recess. Alternatively, the rim 1048 of the heel support and the graphite insert 1000 can be “gear-shaped”, as shown in FIG. 34, to allow the graphite insert 1000 to be inserted into the heel support. Again, the ring 1010 is flexible enough to allow it to be inserted into the heel support. If additional cushioning is desired, the rear sole can be modified as shown in FIGS. 35-37. In this embodiment, a “doughnut-shaped” void 1152 is created in the middle of a rear sole 1150 to support an air-filled cushion 1170 similar in shape to an inner tube for a tire. In addition, several voids 1154 are formed around the periphery of the rear sole to reduce the weight of the rear sole and better exploit the cushioning properties of the air-filled cushion 1170 when the shoe strikes the ground during use. The voids are preferably positioned directly below the knobs 1156 to cushion the force transmitted from the heel support to the knobs. The air cushion 1170 may include a valve 1172 for inflating and deflating the cushion. It will be apparent to those skilled in the art that various modifications and variations can be made in the system of the present invention without departing from the scope or spirit of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the claims and their equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>This is a continuation of application Ser. No. 10/447,003, filed May 28, 2003; which is a continuation of application Ser. No. 10/007,535, filed Dec. 4, 2001, now U.S. Pat. No. 6,604,300; which is a continuation of application Ser. No. 09/641,148, filed Aug. 17, 2000, now U.S. Pat. No. 6,324,772; which is a continuation of application Ser. No. 09/512,433, filed Feb. 25, 2000, now U.S. Pat. No. 6,195,916; which is a continuation of application Ser. No. 09/313,667, filed May 18, 1999, now U.S. Pat. No. 6,050,002; which is a continuation of application Ser. No. 08/723,857, filed Sep. 30, 1996, now U.S. Pat. No. 5,918,384; which is a CIP of Ser. No. 08/291,945, filed Aug. 17, 1994, now U.S. Pat. No. 5,560,126; all of which are incorporated herein by reference. cross-reference-to-related-applications description="Cross Reference To Related Applications" end="tail"?
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to a shoe that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the shoes and shoe systems particularly pointed out in the written description and claims, as well as the appended drawings. To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the shoe includes an upper having a heel region, a rear sole secured below the heel region of the upper, and a rear sole support attached to the upper and configured to secure the rear sole below the heel region of the upper. The rear sole support includes a flexible region positioned below the heel region of the upper and above a portion of the rear sole. The flexible region is sufficiently stiff to support a user while still being sufficiently flexible to flex and spring when the user runs or walks vigorously. The flexible region has an interior portion which in its normal, unflexed state is spaced upwardly from the portion of the rear sole immediately below said interior portion, the interior portion being adapted to flex in a direction substantially perpendicular to the major longitudinal axis of the shoe as it is used. The interior portion of the flexible region preferably is elevated relative to its peripheral portion in a direction toward the heel region of the upper. In certain embodiments the flexible region is an integral part of the rear sole support. The rear sole support may include an integral arch extension extending below the upper from a position proximate the heel region of the upper through a substantial portion of the arch region of the upper to support the arch region. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
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20040630
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20090602
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20061116
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94490.0
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A43B1314
| 2
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BAYS, MARIE D
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HEEL SUPPORT FOR ATHLETIC SHOE
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
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A43B
| 2,004
|
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10,882,733
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ACCEPTED
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Removing a high-k gate dielectric
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A metal oxide layer on a substrate is converted at least partly to a metal layer. At least part of the metal layer is covered by an oxidation resistant cover. The covered layer and underlying metal may be removed, for example, using acid.
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1. A method for making a semiconductor device comprising: forming a metal oxide layer on a substrate; converting at least part of the metal oxide layer to a metal; and covering a converted part of said metal oxide layer with a cap layer. 2. The method of claim 1 including covering a converted part with a cap layer soluble in acid. 3. The method of claim 1 wherein the metal oxide layer is formed by atomic layer chemical vapor deposition. 4. The method of claim 3 further comprising forming metal oxide layers having a dielectric constant greater than 10. 5. The method of claim 1 wherein at least part of the metal oxide layer is converted to a metal layer by exposing the metal oxide layer to hydrogen. 6. The method of claim 5 wherein at least part of the metal oxide layer is converted to a metal layer by exposing the metal oxide layer to a hydrogen based plasma. 7. The method of claim 1 including exposing said cap layer to acid to remove at least a portion of said cap layer and the underlying metal layer. 8. A method for making a semiconductor device comprising: forming a metal oxide layer on a substrate; reducing at least part of the metal oxide layer to a metal layer by exposing the metal oxide layer to hydrogen; and covering at least part of said metal layer with an oxidation resistant layer. 9. The method of claim 8 wherein the metal oxide layer is formed by atomic layer chemical vapor deposition. 10. The method of claim 9 further comprising forming metal oxide layers having a dielectric constant greater than 10. 11. The method of claim 8 including covering with an acid soluble oxidation resistant layer. 12. The method of claim 11 including removing at least a portion of said oxidation resistant layer and the underlying metal layer using acid. 13. A method for making a semiconductor device comprising: forming a metal oxide layer on a substrate; reducing the metal oxide layer to a metal layer by exposing the metal oxide layer to hydrogen; covering said metal layer with an oxidation resistant layer; and removing a covered portion of said metal layer and said oxidation resistant layer. 14. The method of claim 13 wherein the metal oxide layer is formed by atomic layer chemical vapor deposition. 15. The method of claim 14 further comprising forming metal oxide layers having a dielectric constant greater than 10. 16. The method of claim 13 including removing the covered portion of said metal layer and said oxidation resistant layer using acid. 17. A semiconductor structure comprising: a semiconductor substrate; a reduced metal oxide layer over said substrate; a masking layer over a portion of said reduced metal oxide layer, the portion of said reduced metal oxide layer beneath said masking layer being unreduced; and a capping layer formed over said masking layer and said reduced metal oxide layer, said capping layer being removable by acid treatment. 18. The structure of claim 17 wherein the reduced metal oxide layer underneath said masking layer is a high dielectric constant metal oxide layer. 19. The structure of claim 17 wherein said masking layer is formed of polysilicon and includes sidewall spacers. 20. The structure of claim 19 including a hard mask over said masking layer.
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BACKGROUND This invention relates generally to methods for making semiconductor devices, in particular, semiconductor devices that include high dielectric constant (k) gate dielectric layers. MOS field-effect transistors with very thin silicon dioxide based gate dielectrics may experience unacceptable gate leakage currents. Forming the gate dielectric from certain high-k dielectric materials, instead of silicon dioxide, can reduce gate leakage. High-k gate dielectric materials may be difficult to pattern and remove. Thus, better techniques for removing high-k gate dielectrics are needed. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1a-1f represent cross-sections of structures that may be formed when carrying out an embodiment of the method of the present invention. Features shown in these figures are not intended to be drawn to scale. DETAILED DESCRIPTION Referring to FIG. 1a, the substrate 100 may comprise a bulk silicon or silicon-on-insulator substructure. Alternatively, the substrate may comprise other materials—which may or may not be combined with silicon—such as: germanium, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide, or gallium antimonide. Although several examples of materials from which the substrate 100 may be formed are described here, any material that may serve as a foundation upon which a semiconductor device may be built falls within the spirit and scope of the present invention. When the substrate 100 comprises a silicon wafer, the wafer may be cleaned before forming the metal oxide layer on its surface. To clean the wafer, it may initially be exposed to a dilute hydrofluoric acid (“HF”) solution, e.g., a 50:1 water to HF solution. The wafer may then be placed in a megasonic tank, and exposed first to a water/H2O2/NH4OH solution, then to a water/H2O2/HCl solution. The water/H2O2/NH4OH solution may remove particles and organic contaminants, and the water/H2O2/HCl solution may remove metallic contaminants. After that cleaning treatment, metal oxide layer 101 is formed on substrate 100, generating the structure illustrated by FIG. 1a. Materials for making the metal oxide layer 101 include any material that can be used to form a high dielectric constant material. A high dielectric constant is a constant greater than 10. Examples of such materials include hafnium oxide, hafnium silicon oxide, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide, titanium oxide, tantalum oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, and lead scandium tantalum oxide. Particularly preferred are hafnium oxide, zirconium oxide, titanium oxide, and aluminum oxide. Although a few examples of materials that may be used to form metal oxide layer 101 are described here, that layer may be made from other materials, as will be apparent to those skilled in the art. Metal oxide layer 101 may be formed on substrate 100 using a conventional deposition method, e.g., a conventional chemical vapor deposition (“CVD”), low pressure CVD, or physical vapor deposition (“PVD”) process. Preferably, a conventional atomic layer CVD process is used. In such a process, a metal oxide precursor (e.g., a metal chloride) and steam may be fed at selected flow rates into a CVD reactor, which is then operated at a selected temperature and pressure to generate an atomically smooth interface between substrate 100 and metal oxide layer 101. The CVD reactor may be operated long enough to form a layer with the desired thickness. In most applications, metal oxide layer 101 may be less than about 40 Angstroms thick, and more preferably between about 5 Angstroms and about 20 Angstroms thick—i.e., less than or equal to about 5 monolayers thick. A patterned polysilicon layer may be created by first forming a hard mask that covers part of the polysilicon layer, and leaves part of that layer exposed. Such a hard mask may comprise silicon nitride, silicon dioxide, silicon oxynitride, or a nitrided silicon dioxide. The hard mask may be between about 100 Angstroms and about 500 Angstroms thick, and may be deposited and patterned using conventional techniques. The exposed part of the polysilicon layer may then be removed using a dry etch process. Such a dry etch process may employ a plasma that is derived from a combination of gases, e.g., a combination of hydrogen bromide, chlorine, argon, and oxygen. The optimal process for etching the polysilicon layer may depend upon the degree to which the polysilicon layer is doped, and the desired profile for the resulting etched layer. Hard mask 110 may be retained after masking layer 103 is formed to protect masking layer 103 during subsequent etching operations. After forming the FIG. 1a structure, first side 104 and second side 105 of masking layer 103 are lined with a sacrificial layer. To line sides 104, 105 with a sacrificial layer, layer 106 is initially deposited onto metal layer 102, hard mask 110, and sides 104, 105 of masking layer 103, generating the FIG. 1b structure. Examples of materials that may be used to form layer 106 include silicon nitride, a carbon doped silicon nitride, and silicon dioxide. Preferably, layer 106 comprises a material that may be etched selectively to hard mask 110. Layer 106 may be deposited onto metal layer 102, hard mask 110 and sides 104, 105, using a conventional CVD process. In a preferred embodiment, layer 106 has a relatively uniform thickness of between about 10 Angstroms and about 100 Angstroms, and more preferably of between about 30 Angstroms and about 50 Angstroms. After layer 106 is deposited, an anisotropic plasma dry etch process may be applied to remove the horizontal portions of the sacrificial layer 106, generating the FIG. 1c structure. Such a process may employ a plasma that is derived from a combination of CH3F, carbon monoxide, oxygen and argon. That process step leaves layer 101 exposed, except where masking layer 103 covers that layer—while layer 106 continues to protect sides 104, 105. Part or all of metal oxide layer 101 may be converted into metal layer 102 via a chemical reduction process that uses conventional equipment, materials, and operating conditions. In such a chemical reduction process, metal oxide layer 101 may be converted to metal by exposing metal oxide layer 101 to hydrogen, which may be contained in a hydrogen containing gas or a hydrogen based plasma. When a hydrogen containing gas is used, it may comprise hydrogen, or, alternatively, include hydrogen and an inert gas, e.g., helium or argon. When including an inert gas, the hydrogen containing gas may comprise about 5% hydrogen. Prior to exposing metal oxide layer 101 to such a hydrogen containing gas, the reaction chamber may be purged to prevent undesirable reaction between layer 101 and oxygen or nitrogen. The reduction process may take place under ambient conditions. When metal oxide layer 101 is less than or equal to about 20 Angstroms thick, substantially all of that layer may be reduced to metal by feeding enough hydrogen into the reaction chamber to remove substantially all of the oxygen included in metal oxide layer 101. To remove the oxygen and a significant amount of impurities, the ratio of hydrogen atoms (fed into the reaction chamber) to the number of oxygen atoms (contained in the metal oxide layer) must exceed 2:1. When metal oxide layer 101 is reduced to metal by exposing it to a hydrogen based plasma, a direct plasma enhanced chemical vapor deposition (“PECVD”) process or a remote plasma enhanced chemical vapor deposition (“RPECVD”) process may be used. In such a PECVD or RPECVD process, metal oxide layer 101 may be reduced to metal by exposing it to hydrogen and to certain ionized species generated by a plasma source. When a PECVD process is used, such ionized species may be generated by feeding hydrogen and an inert gas into the reactor, then striking a plasma within the reactor. When a RPECVD process is used, the plasma may be stricken remotely, followed by feeding the resulting ionized species and hydrogen (or a mixture of hydrogen and an inert gas) into the reactor—downstream from the plasma source. When metal oxide layer 101 is less than about 20 Angstroms thick, the reactor may be operated under the appropriate conditions (e.g., temperature, pressure, radio frequency, and power) for a sufficient time to reduce all (or substantially all) of metal oxide layer 101 to metal. When layer 101 is significantly greater than 20 Angstroms thick, the reactor may be operated long enough to reduce the upper portion of that layer. Although a few examples of processes that may be used to reduce at least part of metal oxide layer 101 to metal are described here, other reducing operations may be used, as will be apparent to those skilled in the art. Examples include other types of wet or dry chemical reducing processes, e.g., those that use aqueous solutions or plasmas with different reducing agents. Various combinations of these processes may also be employed. As an alternative to such chemical reduction processes, an electrochemical reduction operation may be used. In such a process, metal oxide layer 101 is placed into a chemical bath. By passing an electric current through the bath, part or all of metal oxide layer 101 may be reduced to metal. Processes that may be used to reduce metal oxide layer 101 to metal are not limited to those described above. Regions of the reduced layer 101 to be removed may be covered with a layer 200 (FIG. 1D) in the same chamber used to reduce the layer 101. The layer 200 may be a cap layer that is soluble in acid in one embodiment of the present invention. The layer 200 may include a metal such as titanium nitride or aluminum or other acid soluble materials such as silicon nitride. The layer 200 may be from 25 to 100 Angstroms thick in some embodiments. The layer 200 is effective to prevent reoxidation of the underlying layer 102, for example, while the wafer is being transferred to another station at which station the layer 101 will be removed. Reoxidation would make it more difficult to remove the layer 101 by acid treatments. If the layer 200 is removable by acid treatments to generate the FIG. 1E structure and the reduced layer 101 is removable by acid treatments, the layer 101 can be readily removed by acid exposure to produce the clean substrate 100 shown in FIG. 1F. The acid treatment may include sulfuric or phosphoric acid, as examples. In the illustrated embodiment, at least some of sacrificial layer 106 remains after the exposed part of dielectric layer 101 has been removed. The remaining part of that sacrificial layer is then removed, generating the FIG. 1G structure. A wet etch process may be applied to remove the remaining portion of layer 106. Although in this embodiment some of sacrificial layer 106 remains after dielectric layer 101 has been etched, in other embodiments the wet etch processes that remove part of metal layer 102 and the exposed part of dielectric layer 101 may remove the remainder of sacrificial layer 106 at the same time. Process steps for completing the device that follow removal of the sacrificial layer, e.g., forming sidewall spacers on the gate electrode stack, source and drain regions and the device's contacts, are well known to those skilled in the art and will not be described in more detail here. In this regard, using dummy doped polysilicon layers for masking layer 103 may enable one to apply commonly used nitride spacer, source/drain, and silicide formation techniques, when completing the structure. During those subsequent process steps, hard mask 110 may be retained to prevent a significant part of masking layer 103 from being converted into a silicide. Conversely, if it is desirable to subsequently convert part or all of masking layer 103 into a silicide, then hard mask 110 must be removed beforehand. While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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<SOH> BACKGROUND <EOH>This invention relates generally to methods for making semiconductor devices, in particular, semiconductor devices that include high dielectric constant (k) gate dielectric layers. MOS field-effect transistors with very thin silicon dioxide based gate dielectrics may experience unacceptable gate leakage currents. Forming the gate dielectric from certain high-k dielectric materials, instead of silicon dioxide, can reduce gate leakage. High-k gate dielectric materials may be difficult to pattern and remove. Thus, better techniques for removing high-k gate dielectrics are needed.
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<SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>FIGS. 1 a - 1 f represent cross-sections of structures that may be formed when carrying out an embodiment of the method of the present invention. Features shown in these figures are not intended to be drawn to scale. detailed-description description="Detailed Description" end="lead"?
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20040630
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20090818
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20060105
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65362.0
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H01L21335
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CAO, PHAT X
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REMOVING A HIGH-K GATE DIELECTRIC
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UNDISCOUNTED
| 0
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ACCEPTED
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H01L
| 2,004
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10,882,833
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ACCEPTED
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Method for detecting, reporting and responding to network node-level events and a system thereof
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A system for detecting, reporting and responding to network node-level occurrences on a network-wide level includes one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in the network. An event detection system communicates network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents, and a reporting system disseminates from the one or more first mobile agents information describing the detected event to one or more other nodes
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1. A method for detecting, reporting and responding to network node-level occurrences on a network-wide level, the method comprising: providing one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in a network; communicating network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents; and disseminating from the one or more first mobile agents information describing the detected event to one or more other nodes. 2. The method as set forth in claim 1 further comprising selecting the one or more of the nodes to host the one or more first mobile agents based on determining which one or more of the nodes is best suited to host the one or more first mobile agents. 3. The method as set forth in claim 2 further comprising utilizing at least one of a voting and an artificial intelligence algorithm to perform the determining which one or more of the nodes is best suited to host the one or more first mobile agents. 4. The method as set forth in claim 1 further comprising selecting another one or more of the nodes to host one or more second mobile agents when the one or more first mobile agents become unavailable. 5. The method as set forth in claim 1 wherein the communicating the network event information associated with the event detected at the one or more of the nodes in the network to the one or more first mobile agents further comprises sending the network event information from a first system on each of the one or more nodes which detect the event to the one or more first mobile agents. 6. The method as set forth in claim 5 wherein each of the first systems receives the network event information from a second system on the node which detects the event. 7. The method as set forth in claim 6 wherein the second system responds to the detected event using the network event information to protect the node. 8. The method as set forth in claim 1 wherein the providing the one or more first mobile agents further comprises identifying one or more of the one or more first mobile agents as being an active mobile agent. 9. The method as set forth in claim 8 wherein the communicating the network event information associated with the event detected at the one or more of the nodes in the network to the one or more first mobile agents further comprises: sending the network event information from the one or more nodes which detect the event to the one or more active mobile agents. 10. The method as set forth in claim 9 wherein each of the one or more active mobile agents sends the network event information to a first set of the first mobile agents. 11. The method as set forth in claim 1 further comprising protecting each of the one or more other nodes against a network-based attack associated with the detected event using the information describing the detected event. 12. A computer-readable medium having stored thereon instructions for detecting, reporting and responding to network node-level occurrences on a network-wide level, which when executed by at least one processor, causes the processor to perform: providing one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in a network; communicating network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents; and disseminating from the one or more first mobile agents information describing the detected event to one or more other nodes. 13. The medium as set forth in claim 12 further comprising selecting the one or more of the nodes to host the one or more first mobile agents based on determining which one or more of the nodes is best suited to host the one or more first mobile agents. 14. The medium as set forth in claim 13 further comprising utilizing at least one of a voting and an artificial intelligence algorithm to perform the determining which one or more of the nodes is best suited to host the one or more first mobile agents. 15. The medium as set forth in claim 12 further comprising selecting another one or more of the nodes to host one or more second mobile agents when the one or more first mobile agents become unavailable. 16. The medium as set forth in claim 12 wherein the communicating the network event information associated with the event detected at the one or more of the nodes in the network to the one or more first mobile agents further comprises sending the network event information from a first system on each of the one or more nodes which detect the event to the one or more first mobile agents. 17. The medium as set forth in claim 16 wherein each of the first systems receives the network event information from a second system on the node which detects the event. 18. The medium as set forth in claim 17 wherein the second system responds to the detected event using the network event information to protect the node. 19. The medium as set forth in claim 12 wherein the providing the one or more first mobile agents further comprises identifying one or more of the one or more first mobile agents as being an active mobile agent. 20. The medium as set forth in claim 19 wherein the communicating the network event information associated with the event detected at the one or more of the nodes in the network to the one or more first mobile agents further comprises: sending the network event information from the one or more nodes which detect the event to the one or more active mobile agents. 21. The medium as set forth in claim 12 further comprising protecting each of the one or more other nodes against a network-based attack associated with the detected event using the information describing the detected event. 22. A system for detecting, reporting and responding to network node-level occurrences on a network-wide level, the system comprising: one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in a network; an event detection system that communicates network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents; and a reporting system that disseminates from the one or more first mobile agents information describing the detected event to one or more other nodes. 23. The system as set forth in claim 22 further comprising a mobile agent host selection system that selects the one or more of the nodes to host the one or more first mobile agents based on determining which one or more of the nodes is best suited to host the one or more first mobile agents. 24. The system as set forth in claim 23 wherein the mobile agent host selection system utilizes at least one of a voting and an artificial intelligence algorithm to determine which one or more of the nodes is best suited to host the one or more first mobile agents. 25. The system as set forth in claim 22 further comprising a mobile agent host selection system that selects another one or more of the nodes to host one or more second mobile agents when the one or more first mobile agents become unavailable. 26. The system as set forth in claim 22 wherein the event detection system further comprises a first system on the one or more nodes where the event is detected that sends the network event information to the one or more first mobile agents. 27. The system as set forth in claim 26 wherein the event detection system further comprises a second system on the one or more nodes where the event is detected which detects the event. 28. The system as set forth in claim 27 wherein the second system responds to the detected event using the network event information to protect the node. 29. The system as set forth in claim 22 wherein one or more of the one or more first mobile agents are identified as being an active mobile agent. 30. The system as set forth in claim 29 wherein the event detection system sends the network event information from the one or more nodes which detect the event to the one or more active mobile agents. 31. The system as set forth in claim 22 wherein each of the one or more nodes comprises a first system that protects the nodes against a network-based attack associated with the detected event using the information describing the detected event.
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This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/488,190 filed Jul. 17, 2003 which is hereby incorporated by reference in its entirety. FIELD OF THE INVENTION This invention relates generally to network communications and, more particularly, to a method and system for providing information associated with network events, such as a viral or unauthorized access attack, to a mobile agent hosted by one of a plurality of network nodes, which in turn reports the network event to client modules operating on the other nodes in the network for addressing the network event accordingly. BACKGROUND Current network security systems are primarily insular. These detection systems, such as virus scanners and intrusion detection systems, lack the capability to collaborate events to the controlled network. In other words, they lack the capability and inherent architecture to address attacks from a group perspective. Insular systems could thus be considered passive from a network perspective, as action taken on events has only the scope of network nodes, not the network as a whole. Furthermore, “distributed” defense systems use static, centralized sources of control which has several drawbacks. The foremost drawback is network failure. If a controller, such as a server, fails, the entire network security system is left without control. If the sever is compromised, a malicious entity may gain control of an entire system. Additionally, network conditions, such as segmentation and fragmentation, could lead to entire portions of the network not having access to the static server or the ability to adapt. SUMMARY A system for detecting, reporting and responding to network node-level occurrences on a network-wide level in accordance with embodiments of the present invention includes one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in the network. An event detection system communicates network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents, and a reporting system disseminates from the one or more first mobile agents information describing the detected event to one or more other nodes. A method and a program storage device readable by a machine and tangibly embodying a program of instructions executable by the machine for detecting, reporting and responding to network node-level occurrences on a network-wide level in accordance with embodiments of the present invention include providing one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in the network, communicating network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents, and disseminating from the one or more first mobile agents information describing the detected event to one or more other nodes. The present invention addresses the above-noted problems in current systems by distributing control of a network throughout the nodes of the network, such as computer systems and other programmable machines, themselves with a mobile agent. The mobile agent is “hosted” by one of the network nodes, but can be dispatched from node to node and is not restricted to any particular node. As a result, control of the system in a network is non-central and mobile. This, among other properties, ensures that the system is fault tolerant, meaning that the system remains on-line whenever there is an available host for the mobile agent. Fault tolerance guarantees that a system functions regardless of any node's status on the network. Even if every node is disabled, the present invention enables the system to restore itself to a protected state. Additionally, the present invention allows for adaptation to fragmented networks and allows data gathered in individual partitions to be merged when the network reforms. Thus, if a node is functioning as the host for the mobile agent at any given time and is rendered unavailable, one or more of the other nodes in the network can assume the responsibility for hosting the mobile agent since all of the nodes have a copy of the mobile agent. Determining which node will host the mobile agent can be accomplished using a variety of techniques, such as voting schemes, artificial intelligence, and/or other processing resource management techniques. Another benefit of the present invention is that the invention may distribute and control software along with network events. New attack patterns and forms of transmission change daily, and current systems utilizing out-dated protection software often leads to a compromised system. The present invention addresses these problems by coupling real-time network communication with self-updating facilities. This real-time communication serves to disseminate third-party updates to the entire network, ensuring that all clients have the same underlying degree of protection. With the present invention, there is no inherent limit or defined boundary for the minimum or maximum number of nodes that may be protected. When the network reaches a certain size which can be established by an operator of the network, with the present invention the network may have two distinct mobile agents. Similarly, there is no restriction on the type of node or nodes within a network. The nodes within the network may be of heterogeneous types, such as Microsoft Windows, Unix/Linux, Apple Macintosh, etc. A further benefit of the present invention is that the system is non-invasive with respect to existing security protocols and established frameworks. The present invention can monitor its processes for effective operation and adapts itself to changing environments, i.e., network topology and/or size, as appropriate. Changed configurations are immediately propagated to nodes in the network as required. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a system for detecting and reporting network node-level occurrences and responding on a network-wide level in accordance with embodiments of the present invention; FIG. 2 is a flow chart of a method for detecting and reporting an attack to a node in a system in accordance with embodiments of the present invention; and FIG. 3 is a flow chart of a method for responding to an attack on a node in a system in accordance with embodiments of the present invention. DETAILED DESCRIPTION A system 10 for detecting and reporting network node-level occurrences, such as viral attacks or unauthorized access, and responding on a network-wide level, such as defending a computer network against a viral attack, in accordance with embodiments of the present invention is illustrated in FIG. 1. The system 10 includes a plurality of nodes 12(1)-12(n) coupled together by a communication network 14, each of the nodes 12(1)-12(n) has one of a plurality of mobile agents 26(1)-26(n) although the system 10 can comprise other numbers and types of components in other configurations. The present invention provides a number of advantages, including providing real-time, active protection of a computer network to enable a secure, efficient and fault tolerant system. Referring more specifically to FIG. 1, in these embodiments each of the nodes 12(1)-12(n) has one of a plurality of central processing unit (CPU) or processor 16(1)-16(n), one of a plurality of memories 18(1)-18(n), and one of a plurality of input/output interface devices 20(1)-20(n) which are coupled together in each of the nodes 12(1)-12(n) by one of a plurality of buses 22(1)-22(n) or other link, although each of the nodes 12(1)-12(n) can comprise other numbers and types of components in other configurations and each of the nodes 12(1)-12(n) can comprises other types of systems and devices. Each of the processors 16(1)-16(n) can execute a program of stored instructions for one or more aspects of the present invention as described herein, including the methods described herein with reference to FIGS. 2-3. Each of the memories 18(1)-18(n) can store some or all of these programmed instructions for one or more aspects of the present invention for execution by one or more of the processors 16(1)-16(n), although some or all of these programmed instructions which can include data could be stored and/or executed elsewhere. A variety of different types of memory storage devices, such as a random access memory (RAM) or a read only memory (ROM) in the system or a floppy disk, hard disk, CD ROM, or other computer readable medium which is read from and/or written to by a magnetic, optical, or other reading and/or writing system that is coupled to the processor, can be used for each of the memories 18(1)-18(n) to store the programmed instructions described herein, as well as other information. Each of the memories 18(1)-18(n) also includes one of a plurality of virus protection modules 24(1)-24(n) and one of a plurality of mobile agent modules or mobile agents 26(1)-26(n), although the memories 18(1)-18(n) can stored other numbers and types of modules with programmed instructions for carrying out these and/or other processes. For example, in other embodiments one or more of the nodes 12(1)-12(n) may not have one or more of the virus protection modules 24(1)-24(n) and/or one or more of the mobile agents 26(1)-26(n). Each of the virus protection modules 24(1)-24(n) comprises programmed instructions stored in each of the memories 18(1)-18(n) for execution by each of the processors 16(1)-16(n) to recognize, notify and defend each of the nodes 12(1)-12(n) from an attack, such as an attack from a virus, although each of the virus protection modules 24(1)-24(n) can comprise other numbers and types of complement technologies. By way of example only, a virus protection module may comprise the Norton Antivirus program. Since the operation of virus protection modules are well known to those of ordinary skill in the art, they will not be described in greater detail herein. The mobile agents 26(1)-26(n) are dynamically loaded by the nodes 12(1)-12(n) on the system 10 at the first startup of each of the nodes 12(1)-12(n), although the mobile agents 26(1)-26(n) can be loaded at other times, such as when a failure occurs in the one of the nodes 12(1)-12(n) which is hosting the controlling one of the mobile agents 26(1)-26(n). Each of the mobile agents 26(1)-26(n) comprises programmed instructions stored in each of the memories 18(1)-18(n)for execution by each of the processors 16(1)-16(n) to provide real-time, active protection of a computer system or network 10. More specifically, each of the mobile agents 26(1)-26(n) comprises programmed instructions which include data tables containing the state of the system 10, although each of the mobile agents 26(1)-26(n) can comprise other types of programmed instructions including other data. The state of the system 10 comprises information required by the virus protection modules 24(1)-24(n) to enact defensive measures, as well as administrative and ancillary information required for the functions of each of the nodes 12(1)-12(n). For example, the information about the state of the system 10 may comprises data, such as a virus identifier and/or virus name, and metadata, such as a list of which of the nodes 12(1)-12(n) is/are available for hosting a controlling one of the mobile agents 26(1)-26(n). The state of the system 10 is maintained on all of the nodes 12(1)-12(n) within a mobile-agent controlled sector so that each of the nodes 12(1)-12(n) has the same data as the other nodes 12(1)-12(n), although lesser numbers of the nodes 12(1)-12(n) could be maintained. In these embodiments, there is one mobile-agent sector for the system 10 which controls nodes 12(1)-12(n), although system 10 can have other numbers of mobile agent controlled sectors. A rigorous system of acknowledgement and logging in the system 10 between the nodes 12(1)-12(n) ensures that all transmitted data is effectively received, even in the event of a failure of the controlling one or more of the mobile agents 26(1)-26(n) on the nodes 12(1)-12(n). One or more of the nodes 12(1)-12(n) may be hosting a controlling one or more of the mobile agents 26(1)-26(n) and the other remaining nodes in the nodes 12(1)-12(n) will have non-controlling mobile agents from the remaining ones of the mobile agents 26(1)-26(n). The non-controlling mobile agents from the remaining ones of the mobile agents 26(1)-26(n), also known as client modules, are each used to interact with and control the one or more virus protection modules 24(1)-24(n) which are located in the same nodes 12(1)-12(n) as each non-controlling mobile agent. Although in these embodiments one node in the nodes 12(1)-12(n) hosts only one controlling mobile agent from the mobile agents 26(1)-26(n), the one node can host other numbers of controlling mobile agents. If the one node in the nodes 12(1)-12(n) with the controlling one of the mobile agents 26(1)-26(n) is shut down, another one of remaining nodes in the nodes 12(1)-12(n) can host a controlling mobile agent module from the remaining mobile agents 26(1)-26(n). Only the nodes 12(1)-12(n) in the system 10 can be used to host a controlling one or ones of the mobile agents 26(1)-26(n). The controlling one of the mobile agents 26(1)-26(n) is not restricted to any particular one of the nodes 12(1)-12(n). This promotes fault tolerance ensuring that a system 10 remains on-line whenever there is an available one of the nodes 12(1)-12(n) to host a controlling one of the mobile agents 26(1)-26(n). This also promotes an additional level of security because it is more difficult to locate which of the mobile agents 26(1)-26(n) is controlling. Referring back to FIG. 1, the input/output interface devices 20(1)-20(n) are used to operatively couple and communicate between each of the nodes 12(1)-12(n) via the communications network 14 and also with other systems and devices, such as with for example an outside server 30 via a communication network 28. A variety of communication systems and/or methods can be used for each of the communication networks 14 and 28 to operatively couple and communicate between the nodes 12(1)-12(n) and between one or of the nodes 12(1)-12(n) and other systems and devices, such as the outside server 30, such as wireless communication technology, a direct connection, a local area network, a wide area network, the world wide web, and modems and phone lines each having their own communications protocols. The operation of the system 10 in accordance with embodiments of the present invention will now be described with reference to FIGS. 2-3. In step 100, the virus protection modules 24(1)-24(n) in each of the nodes 12(1)-12(n) monitor for an event, such as an attack on one of the nodes 12(1) or an update. By way of example only, an attack may come from the outside server 30 during a communication between the node 12(1) and the outside server 30 via the communication network 28. The update may also comprise information about an update to one of the virus protection modules 24(1)-24(n ) or another module or modules or may comprise new data. To obtain updates, the controlling one of the mobile agents 26(1)-26(n) in one of the nodes 12(1)-12(n) may continually poll outside sources to look for new information and then disseminate this information to the other nodes 12(1)-12(n), although other manners for obtaining the updates can be used. In step 102, if based on the monitoring, an event is not detected by the virus protection modules 24(1)-24(n) at any of the nodes 12(1)-12(n), then the No branch is taken back to step 100. In step 102, if based on the monitoring, an event is detected by the virus protection modules 24(1)-24(n) at one of the nodes 12(1)-12(n), then the Yes branch is taken to step 104. In step 104, the one of the nodes 12(1)-12(n) which detected the event, responds to the event. By way of example only, if the event is an attack, the one of the nodes 12(1)-12(n) defends itself from the attack using the virus protection modules 24(1)-24(n) at the attacked one of the nodes 12(1)-12(n) and/or may implement new virus protection instructions. If the event is an update, then the one of the nodes 12(1)-12(n) with the controlling one of the mobile agents 26(1)-26(n) may obtain the update. In step 106, the one of the nodes 12(1)-12(n) which detected the event, transmits hash about the event, such as an identifier and ancillary data which the other nodes 12(1)-12(n) with the virus protection modules 24(1)-24(n) can use to determine the appropriate course of action, e.g. how to protect against a new virus, to the node in the nodes 12(1)-12(n) which is currently hosting the controlling mobile agent in the mobile agents 26(1)-26(n). In step 108, the one of the nodes 12(1)-12(n) which detected the event determines if the node in the nodes 12(1)-12(n) which is currently hosting the controlling mobile agent is available. If the node in the nodes 12(1)-12(n) which is currently hosting the controlling mobile agent is available, then the Yes branch is taken to step 112 in FIG. 3. Referring back to FIG. 2, if the node in the nodes 12(1)-12(n) which is currently hosting the controlling mobile agent is not available, then the No branch is taken to step 110. In step 110, another node in the nodes 12(1)-12(n) is selected to host the controlling one of the remaining available mobile agents in the mobile agents 26(1)-26(n) and then returns to step 106. Determining which of the nodes 12(1)-12(n) will host the controlling mobile agent from the mobile agents 26(1)-26(n) can be accomplished using a variety of techniques, such as voting schemes, artificial intelligence, and/or other processing resource management techniques. For example, a weighted voting protocol, i.e., a communication theory for nodes 12(1)-12(n) to unanimously vote on an event, to elect the controlling one of the mobile agents 26(1)-26(n) may be used, although other selection schemes may be used such as artificial intelligence. In this example, the event is a determination of which of the nodes 12(1)-12(n) will host a controlling mobile agent. Voting protocols ensure that if failures occur while a voting session takes place, a node in the nodes 12(1)-12(n) which has failed will not be elected. When a new node in the nodes 12(1)-12(n) is selected to host the controlling mobile agent, the other nodes 12(1)-12(n) in the system 10 are notified of the new node in the nodes 12(1)-12(n) which is hosting the controlling mobile agent. With the notification, the remaining nodes in the nodes 12(1)-12(n) with the non-controlling or client modules know which node in the nodes 12(1)-12(n) with the controlling mobile agent to send and receive data, such as information about a detected attack. Referring to FIG. 3, in step 112 the node in the nodes 12(1)-12(n) which is hosting the controlling mobile agent from the mobile agents 26(1)-26(n) receives information about the event from the node in the nodes 12(1)-12(n) which was attacked. In step 114, the controlling mobile agent in the hosting node checks the information received about the event against stored data about other events. In step 116, the controlling mobile agent in the hosting node determines if the virus protection modules 24(1)-24(n) for the nodes 12(1)-12(n) are up to date with respect to the detected event. If the information received about the detected event is already known at each of the nodes 12(1)-12(n), then the Yes branch is taken to step 120 where the process with respect to this particular event ends while the system 10 continues to monitor for the next event as set forth in step 100. If the information received about the detected event is not already known at each of the nodes 12(1)-12(n), then the No branch is taken to step 118. In step 118, the one of the nodes 12(1)-12(n) which is hosting the controlling mobile agent transmits information about the detected event to the other nodes 12(1)-12(n) which are not hosting the controlling mobile agent and those nodes can update their data. For example, the other nodes 12(1)-12(n) which are not hosting the controlling mobile agent may update the virus protection modules 24(1)-24(n) based on the transmitted information about the detected event. In these embodiments, the nodes 12(1)-12(n) use Message digest (“MD”) and Keyed-Hashing Message Authentication (”HMAC′) for checking hash received about a particular event against stored data in the nodes 12(1)-12(n), although other techniques for checking data can be used. The information which is transmitted from the one of the nodes 12(1)-12(n) which is hosting the controlling mobile agent may be encrypted before being sent out on the system 10 to the other nodes which have client modules. Encryption falls into symmetric and asymmetric authentication. Symmetric keys follow the standard for most encryption measures, where a message is encrypted and decrypted using the same key. Asymmetric measures are usually public/private key systems, where hosts have both a private key (for decrypting messages) and a public key (which other hosts use to encrypt messages), although other methods may be used. In step 120, the process with respect to this particular detected event ends, while the system 10 continues to monitor for the next event as set forth in step 100. While the present invention has been described above utilizing complement technology, such as virus detection software, for example, one of ordinary skill in the art in the computer science, network resource management, and distributed network arts will appreciate that the systems and processes disclosed herein may be applied in a number of other network environments utilizing a variety of other complement technologies for detecting, reporting and responding to network events besides virus detection systems, such as any environment which requires a control structure where a distributed architecture is appropriate to the application scale. Having thus described the basic concept of the invention, it will be rather apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. Various alterations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and scope of the invention. Further, the recited order of elements, steps or sequences, or the use of numbers, letters, or other designations therefor, is not intended to limit the claimed processes to any order except as may be explicitly specified in the claims. Accordingly, the invention is limited only by the following claims and equivalents thereto.
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<SOH> BACKGROUND <EOH>Current network security systems are primarily insular. These detection systems, such as virus scanners and intrusion detection systems, lack the capability to collaborate events to the controlled network. In other words, they lack the capability and inherent architecture to address attacks from a group perspective. Insular systems could thus be considered passive from a network perspective, as action taken on events has only the scope of network nodes, not the network as a whole. Furthermore, “distributed” defense systems use static, centralized sources of control which has several drawbacks. The foremost drawback is network failure. If a controller, such as a server, fails, the entire network security system is left without control. If the sever is compromised, a malicious entity may gain control of an entire system. Additionally, network conditions, such as segmentation and fragmentation, could lead to entire portions of the network not having access to the static server or the ability to adapt.
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<SOH> SUMMARY <EOH>A system for detecting, reporting and responding to network node-level occurrences on a network-wide level in accordance with embodiments of the present invention includes one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in the network. An event detection system communicates network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents, and a reporting system disseminates from the one or more first mobile agents information describing the detected event to one or more other nodes. A method and a program storage device readable by a machine and tangibly embodying a program of instructions executable by the machine for detecting, reporting and responding to network node-level occurrences on a network-wide level in accordance with embodiments of the present invention include providing one or more first mobile agents, each of the one or more first mobile agents is hosted by one of a plurality of nodes in the network, communicating network event information associated with an event detected at one or more of the nodes in the network to the one or more first mobile agents, and disseminating from the one or more first mobile agents information describing the detected event to one or more other nodes. The present invention addresses the above-noted problems in current systems by distributing control of a network throughout the nodes of the network, such as computer systems and other programmable machines, themselves with a mobile agent. The mobile agent is “hosted” by one of the network nodes, but can be dispatched from node to node and is not restricted to any particular node. As a result, control of the system in a network is non-central and mobile. This, among other properties, ensures that the system is fault tolerant, meaning that the system remains on-line whenever there is an available host for the mobile agent. Fault tolerance guarantees that a system functions regardless of any node's status on the network. Even if every node is disabled, the present invention enables the system to restore itself to a protected state. Additionally, the present invention allows for adaptation to fragmented networks and allows data gathered in individual partitions to be merged when the network reforms. Thus, if a node is functioning as the host for the mobile agent at any given time and is rendered unavailable, one or more of the other nodes in the network can assume the responsibility for hosting the mobile agent since all of the nodes have a copy of the mobile agent. Determining which node will host the mobile agent can be accomplished using a variety of techniques, such as voting schemes, artificial intelligence, and/or other processing resource management techniques. Another benefit of the present invention is that the invention may distribute and control software along with network events. New attack patterns and forms of transmission change daily, and current systems utilizing out-dated protection software often leads to a compromised system. The present invention addresses these problems by coupling real-time network communication with self-updating facilities. This real-time communication serves to disseminate third-party updates to the entire network, ensuring that all clients have the same underlying degree of protection. With the present invention, there is no inherent limit or defined boundary for the minimum or maximum number of nodes that may be protected. When the network reaches a certain size which can be established by an operator of the network, with the present invention the network may have two distinct mobile agents. Similarly, there is no restriction on the type of node or nodes within a network. The nodes within the network may be of heterogeneous types, such as Microsoft Windows, Unix/Linux, Apple Macintosh, etc. A further benefit of the present invention is that the system is non-invasive with respect to existing security protocols and established frameworks. The present invention can monitor its processes for effective operation and adapts itself to changing environments, i.e., network topology and/or size, as appropriate. Changed configurations are immediately propagated to nodes in the network as required.
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20040701
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20100223
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20050120
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96612.0
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HO, ANDY
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METHOD FOR DETECTING, REPORTING AND RESPONDING TO NETWORK NODE-LEVEL EVENTS AND A SYSTEM THEREOF
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SMALL
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ACCEPTED
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10,882,947
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ACCEPTED
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RFID device preparation system and method
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An RFID device preparation system includes a printer combined with a short-range tester/reader. The tester/reader operatively couples to the RFID device using capacitive and/or magnetic coupling. By use of capacitive and/or magnetic coupling, good read characteristics may be obtained, while obtaining excellent discrimination between various RFID devices that may be in or near the tester/reader. Thus, RFID devices may be inexpensively and reliably tested one at a time, without appreciable interference or effect due to the presence of other RFID devices. The tester/reader may include electric-filed and/or magnetic-field coupling elements that are configured to receive different signals, in order to test a variety of configurations of RFID devices. This may enable the device preparation system to accommodate various types and configurations of RFID devices, increasing versatility of the system.
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1. An RFID device preparation system comprising: a tester/reader for interacting with a plurality of RFID devices on a sheet or roll; and a printer for printing on a layer of the RFID devices; wherein the tester/reader includes one or more reactive coupling elements that interact with the RFID devices through reactive coupling. 2. The device of claim 1, wherein the one or more reactive coupling elements include one or more electric-field coupling elements for interacting with the RFID devices through capacitive coupling. 3. The device of claim 2, wherein the one or more electric-field coupling elements include one or more electrodes coupled to a signal generator for reactively interacting with the RFID devices in any of a variety of orientations relative to the tester/reader. 4. The device of claim 3, wherein the one or more electrodes include multiple electrodes. 5. The device of claim 4, wherein the electrodes include a pair of L-shaped electrodes. 6. The device of claim 5, wherein the signal generator is configured to provide out-of-phase AC signals to the L-shape electrodes. 7. The device of claim 4, wherein the electrodes include pairs of electrodes angled relative to one another. 8. The device of claim 7, wherein the signal generator is configured to selectively provide out-of-phase signals to two of the electrodes; and wherein the two electrodes are selected based upon an orientation of the RFID devices relative to the electrodes. 9. The device of claim 7, wherein the electrodes include at least eight electrodes. 10. The device of claim 9, wherein the electrodes are substantially axisymmetrically spaced about a point. 11. The device of claim 3, wherein the one or more electrodes include a partially-resistive electrode coupled to the signal generator at multiple drive points. 12. The device of claim 11, wherein the partially-resistive electrode is substantially rectangular. 13. The device of claim 12, wherein the drive points are at corners of the partially-resistive electrode. 14. The device of claim 11, wherein the signal generator is configured to vary phase and amplitude of signals sent to the drive points. 15. The device of claim 3, wherein the tester/reader also includes a magnetic-field coupling element for magnetic coupling to the RFID devices. 16. The device of claim 15, wherein the magnetic-field coupling element includes a coil. 17. The device of claim 3, wherein the tester/reader further includes a high dielectric constant material in proximity to the one or more electrodes. 18. The device of claim 17, wherein the high dielectric constant material is configured to be at least partially between the one or more electrodes, and the RFID devices, when the RFID devices are read. 19. The device of claim 1, wherein the one or more reactive coupling elements include one or more magnetic-field coupling elements for interacting with the RFID devices through magnetic coupling. 20. The device of claim 19, wherein the one or more magnetic-field coupling elements include a coil. 21. The device of claim 19, wherein the tester/reader further includes a high permeability material in proximity to the one or more electrodes. 22. The device of claim 21, wherein the high permeability material is configured to be at least partially between the one or more electrodes, and the RFID devices, when the RFID devices are read. 23. A tester/reader for interacting with a plurality of RFID devices on a sheet or roll, wherein the tester/reader comprises: one or more electric-field coupling elements for interacting with the RFID devices through capacitive coupling; and a signal generator coupled to the one or more electric-field coupling elements; wherein the one or more electric-field coupling elements are configured for capacitively interacting with the RFID devices in any of a variety of orientations relative to the tester/reader. 24. The device of claim 23, wherein the one or more electric-field coupling elements include one or more electrodes. 25. The device of claim 24, wherein the one or more electrodes include multiple electrodes. 26. The device of claim 25, wherein the electrodes include a pair of L-shaped electrodes. 27. The device of claim 26, wherein the signal generator is configured to provide out-of-phase AC signals to the L-shape electrodes. 28. The device of claim 25, wherein the electrodes include pairs of electrodes angled relative to one another. 29. The device of claim 28, wherein the signal generator is configured to selectively provide out-of-phase signals to two of the electrodes; and wherein the two electrodes are selected based upon an orientation of the RFID devices relative to the electrodes. 30. The device of claim 28, wherein the electrodes include at least eight electrodes. 31. The device of claim 30, wherein the electrodes are substantially axisymmetrically spaced about a point. 32. The device of claim 24, wherein the one or more electrodes include a partially-resistive electrode coupled to the signal generator at multiple drive points. 33. The device of claim 32, wherein the partially-resistive electrode is substantially rectangular. 34. The device of claim 33, wherein the drive points are at corners of the partially-resistive electrode. 35. The device of claim 32, wherein the signal generator is configured to vary phase and amplitude of signals sent to the drive points. 36. The device of claim 24, wherein the tester/reader also includes a magnetic-field coupling element for magnetic coupling to the RFID devices. 37. The device of claim 36, wherein the magnetic-field coupling element includes a coil. 38. The device of claim 24, wherein the tester/reader further includes a high dielectric constant material in proximity to the one or more electrodes. 39. The device of claim 38, wherein the high dielectric constant material is configured to be at least partially between the one or more electrodes, and the RFID devices, when the RFID devices are read.
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BACKGROUND OF THE INVENTION 1. Technical Field The invention relates to systems and methods for preparing RFID devices. 2. Background of the Related Art Radio frequency identification (RFID) tags and labels (collectively referred to herein as “devices”) are widely used to associate an object with an identification code. RFID devices generally have a combination of antennas and analog and/or digital electronics, which may include for example communications electronics, data memory, and control logic. For example, RFID tags are used in conjunction with security-locks in cars, for access control to buildings, and for tracking inventory and parcels. Some examples of RFID tags and labels appear in U.S. Pat. Nos. 6,107,920, 6,206,292, and 6,262,292, all of which are hereby incorporated by reference in their entireties. As noted above, RFID devices are generally categorized as labels or tags. RFID labels are RFID devices that are adhesively or otherwise have a surface attached directly to objects. RFID tags, in contrast, are secured to objects by other means, for example by use of a plastic fastener, string or other fastening means. RFID devices include active tags and labels, which include a power source, and passive tags and labels, which do not. In the case of passive tags, in order to retrieve the information from the chip, a “base station” or “reader” sends an excitation signal to the RFID tag or label. The excitation signal energizes the tag or label, and the RFID circuitry transmits the stored information back to the reader. The “reader” receives and decodes the information from the RFID tag. In general, RFID tags can retain and transmit enough information to uniquely identify individuals, packages, inventory and the like. RFID tags and labels also can be characterized as to those to which information is written only once (although the information may be read repeatedly), and those to which information may be written during use. For example, RFID tags may store environmental data (that may be detected by an associated sensor), logistical histories, state data, etc. As the price of RFID devices goes down, such devices are used in a wider variety of applications. It may be desirable for some applications to put individualized visual information on the RFID device. To that end, the RFID device may include or be coupled to a label that may be printed with visual information. The visual information may be machine-readable information, or may be information intended for identification and reading by a person. An example of a system for printing information on an RFID label is the system described in International Publication No. WO 02/35463, which is incorporated by reference in its entirety. Some effort has been made in prior systems to provide encoding or programming of an RFID device in conjunction with a printing operation. Examples of such systems are those described in U.S. Pat. Nos. 6,246,326 and 6,593,853. Notwithstanding these prior devices and methods, improvements would be desirable with regard to combining printing operations with interaction with an RFID device. SUMMARY OF THE INVENTION According to an aspect of the invention, a system for preparing RFID devices includes a tester/reader that interacts with RFID devices in any through reactive coupling. The reactive coupling may be capacitive, magnetic, or a combination of both. The system may also include a printer for printing on a facestock or other layers of the RFID devices. The RFID devices may be on a roll or sheet having multiple such devices. The tester/reader may have multiple electric-field coupling elements and/or magnetic-field coupling elements, to accommodate different possible orientations of the RFID devices relative to the tester/reader. For example, the tester/reader may have multiple electrodes, such as L-shape or other non-straight electrodes Alternatively, the tester/reader may have a partially-resistive electrode with multiple drive points that may be driven with AC signals of different amplitudes and/or phases. The partially-resistive electrode may be substantially rectangular, with drive points at the corners. As another alternative, the tester/reader may have one or more magnetic-field coupling elements such as coils. According to another aspect of the invention, an RFID device preparation system includes a tester/reader for interacting with a plurality of RFID devices on a sheet or roll; and a printer for printing on a layer of the RFID devices. The tester/reader interacts with the RFID devices through reactive coupling. According to yet another aspect of the invention, a tester/reader for interacting with a plurality of RFID devices on a sheet or roll, wherein the tester/reader includes: one or more electric-field coupling elements for interacting with the RFID devices through capacitive coupling; and a signal generator coupled to the one or more electric-field coupling elements. The one or more electric-field coupling elements are configured for capacitively interacting with the RFID devices in any of a variety of orientations relative to the tester/reader. To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. BRIEF DESCRIPTION OF DRAWINGS In the annexed drawings, which are not necessarily to scale: FIG. 1 is a block diagram of an RFID device preparation system in accordance with the present invention; FIG. 2 is a block diagram of a tester/reader of the RFID device preparation system of FIG. 1; FIG. 3 is a plan view of a portion of an RFID device to be prepared by the system of FIG. 1; FIG. 4 is a plan view showing a web or sheet containing multiple of the RFID devices of FIG. 3; FIG. 5 is a plan view showing a first electrode configuration that may be utilized in the tester/reader of FIG. 2, for capacitively coupling to an RFID device for reading and/or testing the device; FIG. 6 is a plan view showing a second electrode configuration that may be utilized in the tester/reader of FIG. 2, for capacitively coupling to an RFID device for reading and/or testing the device; FIG. 7 is a plan view showing a third electrode configuration that may be utilized in the tester/reader of FIG. 2, for capacitively coupling to an RFID device for reading and/or testing the device; FIG. 8 is a plan view of an RFID device that may be magnetically coupled to be tested and/or read by the tester/reader of FIG. 2; FIG. 9 is conceptual view of magnetic coupling between the RFID device of FIG. 8 and the tester/reader of FIG. 2; and FIG. 10 is an oblique of an electrode configuration of a tester/reader that uses both magnetic and capacitive coupling. DETAILED DESCRIPTION An RFID device preparation system includes a printer combined with a short-range tester/reader. The tester/reader operatively couples to the RFID device using capacitive and/or magnetic coupling. By use of capacitive and/or magnetic coupling, good read characteristics may be obtained, while obtaining excellent discrimination between various RFID devices that may be in or near the tester/reader. Thus, RFID devices may be inexpensively and reliably tested one at a time, without appreciable interference or effect due to the presence of other RFID devices. The tester/reader may include electric-filed and/or magnetic-field coupling elements that are configured to receive different signals, in order to test a variety of configurations of RFID devices. This may enable the device preparation system to accommodate various types and configurations of RFID devices, increasing versatility of the system. Turning now to FIG. 1, an RFID device preparation system 10 includes a printer 12, a tester/reader 14, and, optionally, a reader/writer 16. All of the parts of the RFID device preparation system 10 may be included in a single housing. Alternatively, the parts of the system 10 may be placed in close proximity to one another. The printer 12 may be used to print text, graphics, or identifying indicia on the RFID tag or label. An example of a system for printing RFID tags or labels may be found in U.S. Pat. No. 6,246,326. The tester/reader 14 provides a way to quickly test operation of an RFID device. The tester/reader 14 may have a short-range reactive coupling mechanism, such as capacitive and/or magnetic coupling between the tester/reader 14 and the RFID device. The optional reader/writer 16 may be used to program the RFID device. The reader/writer 16, if present, may also have a short-range coupling mechanism such as capacitive and/or magnetic coupling. Indeed, the tester/reader 14 and the reader/writer 16 may be combined into a single element or structure, that both tests and writes to (programs) the RFID device. The reader/writer 16 may have a longer time in communication with the RFID device, compared with the tester/reader 14. A longer communication time may be necessary because programming of the RFID device may require more interaction and communication than merely testing operation of the RFID device. Referring now to FIG. 2, the tester/reader 14 may have control electronics 20, a signal generator 22, and one or more electric-field coupling elements, such as electrodes 24. The control electronics 20 provide guidance to the signal generator 22 as to what sort of signals are to be transmitted by the electrodes 24. The control electronics 20 may store information regarding different types of tags, and/or different orientations of tags that are possible. Information may be entered into the control electronics 20 regarding the types and/or orientations of RFID devices to be encountered by the system 10. Depending on the type and/or orientation of RFID devices, the signals generated by the signal generator 22 to the one or more electrodes 24 may be configured to test and/or read the RFID devices. The tester/reader 14 may also be configured to detect the response of the RFID device, for example, thereby determining whether the RFID device is functioning properly. It will be appreciated that the tester/reader 14 may have other suitable components for performing operations. Capacitive coupling and/or magnetic coupling are referred to collectively herein as “reactive coupling,” in contrast to direct electrical coupling by electrically conductive material. In such reactive coupling, signals from the signal generator 22 may be coupled between overlapping regions of an RFID device and the electrodes 24 of the tester/reader 14. References herein to capacitive, magnetic, or reactive coupling refer to coupling that is predominantly or primarily capacitive, magnetic, or reactive. It will be appreciated that coupling that is primarily capacitive may also include some inductive (magnetic) coupling as a secondary coupling mechanism. Conversely, coupling that is primarily magnetic may also include some capacitive coupling. Systems using primarily capacitive or magnetic coupling are referred to herein as utilizing reactive coupling. Capacitive, magnetic, or reactive coupling, as the terms are used herein, may also include some direct conductive coupling, albeit not as the primary type of electrical coupling. Devices or elements for capacitive coupling are referred to herein as electric-field coupling devices or elements. Similarly, devices or elements for magnetic coupling are referred to herein as magnetic-field coupling devices or elements. Collectively, electric-field coupling devices or elements and magnetic-field coupling devices or elements are referred to as reactive coupling devices or elements. FIG. 3 shows one type of RFID device that may be read, tested, and/or programmed by the RFID device preparation system 10 (FIG. 1). The RFID device 40 shown in FIG. 3 has a transponder or RFID chip 42 operatively coupled to antenna elements 44 and 46 of the dipole antenna 48. The RFID device 40 may be a part of other device such as tags or labels. The tag or label may have a printable face stock for printing, by the printer 12 (FIG. 1), visual identifiers or other information thereupon. The chip 42 may include any of a variety of suitable electronic components, such as the circuitry described above for modulating the impedance of the RFID device 40. It will be appreciated that alternatively the antenna 48 may have another layout. The antenna elements 44 and 46 may be mounted on a dielectric substrate 49 of the RFID device 40. As shown in FIG. 4, the RFID device 40 may be part of a roll or web 50 of multiple of such devices. The dielectric substrate 49 of the RFID device 40 may be part of a sheet of dielectric material, such as a roll of dielectric material, upon which other RFID devices are formed. It will be appreciated that the configuration of the RFID devices 40 relative to the roll or web 50 may be in a wide variety of suitable orientations. Further, it will be appreciated that there may be any of a wide variety of spacings between the RFID devices, for example, with areas between the RFID devices 40 filled with other parts of tags or labels, such as printable portions of tags or labels. FIG. 5 shows one configuration for the electrodes 24 of the tester/reader 14. The electrodes 61-68 shown in FIG. 5 are configured for capacitive coupling with an RFID device such as the dipole antenna RFID device 40 (FIG. 3). The signal generator 22 (FIG. 2) may be configured to send various appropriate signals to some of the electrodes 61-68, to allow coupling of RFID devices in various configurations relative to the electrodes 61-68. Three examples of possible locations for the RFID device 40 are indicated by reference numbers 71, 72, and 73 in FIG. 5. An RFID device in position 71 may be capacitively read by inputting a signal to the electrode 64, and a corresponding signal, 180 degrees out of phase, to the electrode 68. For an RFID device in a vertical orientation, indicated by reference number 72 in FIG. 5, out-of-phase AC signals may be sent to the electrodes 62 and 66. For an RFID device in an offset position, such as the position indicated by reference 73 in FIG. 5, out-of-phase AC signals may be sent to a pair of the diagonal electrodes, such as the electrodes 61 and 67. It will be appreciated that a wide variety of other configurations of an RFID device 40 relative to the electrodes 24 may be suitably read by choosing the electrodes to which signals are sent. The control electronics 20 (FIG. 2) may be utilized to suitably direct signals to appropriate of the electrodes 61-68. Information concerning the configuration of RFID devices 40 on the roll 50 (FIG. 4) may be transmitted to the RFID device preparation system 10 (FIG. 1) by any of a variety of suitable ways. For example, information may be encoded at the beginning or otherwise as a part of the roll 50. As another example, information on the configuration of the RFID devices 40 and/or information on the signals to be sent to the electrodes 61-68 may be entered into the RFID device preparation system 10 by other methods. It may be possible to encode such information in an additional RFID device placed, for example, at the beginning of the roll 50. The RFID device tester/reader 14 and the RFID device 40 may be capacitively coupled together, to transfer power and/or signals between the RFID device tester 14 and the RFID device 40. The operative electrodes of the electrodes 61-68 may be operatively coupled to the antenna elements 44 and 46 (FIG. 3). The antenna elements 44 and 46 and the operative electrodes may function as plates of capacitors, enabling the capacitive coupling between the RFID device tester/reader 14 and the RFID device 40. Once the RFID device tester/reader 14 and the RFID device 40 are capacitively coupled together, electrical power and/or signals may be transferred between the two. The tester/reader 14 may send an outgoing signal, such as an outgoing AC signal, to a pair of the electrodes 61-68. AC power received by the antenna elements 44 and 46 may be rectified by the chip 42, for instance by transistors and/or diodes that are part of the chip 42, to produce DC power to run the chip 42. The power may be used by the chip 42 to send a return signal via the antenna elements 44 and 46. It will be appreciated that the sending of the return signal may be a passive process, rather than active transmission of a return signal by the RFID device 40. As one example, circuitry in the chip 42 may be used to modulate impedance of the RFID device 40. As another example, the RFID device 40 may reflect the incident signal back to the tester/reader 14. It will be appreciated that the RFID device 40 either may be a passive device that automatically responds to an incident signal, or may be an active device that only responds to incident signals conforming to certain protocols. The RFID device 40 may also have other components, such as its own power supply. It will be further appreciated that the functioning of the RFID device 40 may be substantially the same as if incident energy was provided by a long-range RF field, rather than by capacitive coupling. Alternatively, the functioning of the RFID device 40 may be different, depending upon how the incident energy is provided to it. The tester/reader 14 is able to interpret the return signal received from the RFID device 40 to confirm proper function of all or part of the RFID device 40, such as correct functioning of the antenna 48 and/or the chip 42. The confirming of proper functioning may include merely detecting the presence of the RFID device 40, such that if the RFID device 40 is detectable at all, functioning of the RFID device 40 is acceptable, and the RFID device 40 passes the test. Alternatively, the test may involve evaluation of the return signal received from the RFID device 40, for example to determine if the return signal conforms to one or more parameters or ranges of parameters. As another alternative, a successful test may involve confirmation of success in programming the RFID chip 42 and/or sending information to the RFID chip 42 for storage in the RFID chip 42. It will be appreciated that other tests of operation of the RFID device 40 may be employed, for example diagnosing faults of the RFID device 40 or otherwise qualitatively evaluating performance of the RFID device 40. The outgoing AC power signal sent out by the tester/reader 14 and the return signal generated by the RFID device 40 have been described above for clarity as separate signals, one sent out by the tester/reader 14, and the other received by the tester/reader 14. In actuality, it will be appreciated that the signals may in fact be superimposed upon one another, in that the tester/reader 14 perceives a superposition of the outgoing signal and the return signal. Therefore the interpretation of the return signal by the tester/reader 14 may involve a comparison between the outgoing signal and the signal perceived by the tester/reader 14, a superposition of the outgoing signal and the return signal. The RFID device tester/reader 14, which capacitively couples to the RFID device 40, advantageously allows short-range coupling between tester/reader 14 and RFID device 40. As noted above, the RFID device 40 may be part of a sheet or roll having many RFID devices thereupon, and by using short-range capacitive coupling between the RFID device tester/reader 14 and the RFID device 40, better testing of the RFID device 40 may be accomplished, compared with testers coupling to RFID devices via RF fields sent over free space. One reason for the advantage of the capacitively-coupling RFID device tester/reader 14 is that the short-range capacitive coupling is less prone to provide energy to other RFID devices on the same roll or sheet. By reducing or limiting the providing of energy to RFID devices other than the RFID device 40 to be tested, there is better discrimination in the testing, and thus improved testing of the RFID device 40. Appropriate selection of the frequency of the outgoing signal from the tester/reader 14 may allow further reduction in undesired coupling to RFID devices other than the RFID device 40 that is being tested. In explaining this further, it will be useful to define a natural resonate frequency of the antenna 48 as the frequency at which the antenna 48 best receives energy from an external RF field, and at which it best sends energy, when not located in close proximity to the RFID device tester/reader 14. This natural resonant frequency is the frequency at which an antenna impedance of the antenna 48 is the complex conjugate of a chip impedance of the chip 42. The resonant frequency is also referred to herein as the optimum operating point or optimum operating frequency of the RFID device 40. It will be appreciated that the resonant frequency of the antenna 48 may be highly dependent on the configuration of the antenna 48. One advantage of the RFID device tester/reader 14, which capacitively couples to the RFID device 40, is that the outgoing power signal from the tester/reader 14 may be at a frequency that is different from the natural resonant frequency of the antenna 48 of the RFID device 40 (different from the natural optimum operating point of the RFID device 40). By having the outgoing power signal at a different frequency from the natural resonant frequency for the antenna 48 of the RFID device 40, longer-range coupling may be minimized of the outgoing signals to RFID devices other than the desired RFID device 40 to be tested. This is because antennas of the RFID devices are less susceptible to receive significant amounts of power at frequencies different from the resonant frequency of the antenna 48. Further, having the outgoing power signal at a different frequency than the natural resonant frequency of the antenna 48 may reduce cross-coupling between the various antennas of various RFID devices on the same roll or sheet. The operating frequency of the RFID device tester/reader 14 may be selected so as to provide sufficient energy to activate the RFID device 40 that is being tested, and avoiding providing substantial amounts of energy to other RFID devices that may otherwise produce signals interfering with test results. As suggested by the above discussion, the tester operating frequency may be different from the natural resonant frequency of the antenna 48, and/or may be substantially the same as the new resonant frequency of the antenna 48 (the resonant frequency of the antenna 48 as shifted due to its proximity to the RFID device tester/reader 14). Alternatively, the tester operating frequency may be selected from a broad range of suitable RF frequencies for operatively coupling the tester/reader 14 and the RFID device 40. The RF frequencies utilized may be greater than or less than the antenna natural frequency and/or the new antenna resonant frequency (shifted due to the proximity of the tester/reader 14 to the RFID device 40). It will be appreciated, however, that RF frequencies that stray too far from the new antenna resonant frequency (shifted optimum operating frequency) may be unsuitable. For example, there may be a lower limit for suitable RF frequencies due to increases in impedance of capacitive paths, for a given coupling area, as frequencies are reduced. This increase in impedance may make it more difficult to send power into the chip. As another example of a reason for a lower frequency limit, there may be an integrating filter downstream of internal rectifiers in the chip 42, to aid in creating the DC power supply to run the chip 42. If the frequency of the incident RF energy received from the tester/reader 14 is too low, the filter may be unable to adequately smooth the rectified waveform output from the rectifiers. The result may be an unacceptable DC power supply for the chip 42. Further details concerning capacitive coupling and communication between tester/readers and RFID chips may be found in commonly-assigned U.S. patent application Ser. No. 10/367,515, filed Feb. 13, 2003, and International Application No. PCT/US04/04227, filed Feb. 13, 2004. Both of these applications are hereby incorporated by reference in their entireties. The results of testing of the RFID device 40 by the tester/reader 14 may be used to determine whether or what to print on facestock or other printable layer of the RFID device 40. If the RFID device 40 is successfully tested, the printer (FIG. 1) may be configured to print suitable identifying or information on the facestock. If the RFID device 40 fails testing, the printer 12 may be configured to either not print on the facestock or to print some indication (such as an “X”) indicating that the RFID device 40 is not to be used. FIG. 6 shows another configuration for the electrodes 24, which also may be used in capacitively coupling the electrodes 24 to RFID devices 40 in any of a variety of orientations. The electrodes 24 shown in FIG. 6 include a pair of L-shaped electrodes 81 and 82 that are configured to combine to form a substantially rectangular RFID device reading area 83. It will be appreciated that the electrodes 81 and 82 may have other suitable shapes to cover different orientations of RFID devices in the area 83, which may be a rectangular area. The sizes and configurations of the electrodes 81 and 82 may be selected so as to cover a large reading area and/or a large variety of possible orientations of the RFID device 40, while also maintaining desired selectivity between the various RFID devices 40 on the web or sheet 50 (FIG. 4). That is, the size and shape of the electrodes 81 and 82 may be selected so as to allow testing of individual RFID devices, one at a time. To that end, it may be desirable to have the electrodes 81 and 82 be sized to be smaller than the spacing between adjacent of the RFID devices 40 on the sheet or web 50. Turning now to FIG. 7, another possible electrode configuration 24 is shown. The configuration shown in FIG. 7 includes a partially-resistive material 90, with drive points 91-94 at corners of the partially-resistive material 90. The partially-resistive material 90 may have a resistivity of 50 ohms/square, although it will be appreciated that the material may have a different resistivity. RF signals of controllable phase and amplitude may be introduced at the drive points 91-94. By controlling the phase and amplitude of signals at the drive points 91-94, defined current flows may be created in the partially-resistive material 90. As the material 90 is partially resistive, appropriate driving by placing signals at the drive points 91-94 can create voltage profiles, which can couple to test an RFID device via an electric field (capacitive testing), by a magnetic field, or by a combination of both. For example, drive points 91 and 94 are driven by a signal with a relative amplitude of 1 and a relative phase of 0°, and drive points 92 and 93 are driven by a signal of relative amplitude 1 and a relative phase of 180°. This driving would create a line of zero voltage along the center of the material 90, indicated in FIG. 7 by reference number 96. An RFID device centered along the line 96 and perpendicular to the line 96, indicated by the position 98 shown in FIG. 7, would be read as long as a center region of the RFID device traverses the line 96. As another example, if signals of the same relative amplitude, but 180° out of phase, are provided to drive points 91 and 93, a line of zero voltage may be created diagonally across the material 90. This line is indicated by reference number 100 in FIG. 7. By changing the termination impedance and/or driving inputs at the other drive points 92 and 93, the angle and shape of the voltage/current profiles may be controlled. It will be appreciated that by varying the relative amplitude of the driving signals at the drive points 91-94, the position of a read line may be varied across different parts of the partially-resistive material 90. It will also be appreciated that the electrode configuration 24 shown in FIG. 7 provides a way of obtaining continuously variable amplitudes and read angles across the tester/reader 14. As stated above, coupling may be via either electric field or by magnetic field generated by the current flow, or a combination of the two. The electrode configurations shown in FIGS. 5-7 may couple to RFID devices primarily by an electric field induced across a parallel plate capacitor formed by proximity and overlap between the tester/reader 14 and the RFID device 40 under test. FIG. 8 shows an RFID device 120 that includes an antenna 122 coupled to a transponder chip 123. The antenna 122 has a conductive path 124 that acts as an inductor. As illustrated in FIG. 9 a coil 130 coupled to a reader 132 may be used as a magnetic field coupling device or element to magnetically couple to the antenna 122. The coil 130 may be a single-turn coil or a multi-turn coil. Magnetic coupling decays in proportion to the third power with distance between the coil 130 and the RFID device 120. This allows magnetic coupling to be suitable for short-range coupling for coupling together one of a number of closely spaced RFID devices to the reader. It is possible to use both magnetic and capacitive coupling simultaneously, for example, by using different coupling elements for each. The magnetic and capacitive coupling may be configured to operate either additively at a position, or antagonistically, by controlling the relative phase and amplitude of the signals induced by the two modes. By controlling operation of the magnetic and capacitive coupling in such a manner, very precise control may be had regarding read location for the reader/tester. This may be useful for reading/testing small RFID devices. For instance, using electrical field and magnetic field signals opposite in phase, the capacitive coupling and the magnetic coupling may be made to cancel out except at a precise location, such as a null location where the magnetic filed coupling substantially drops to zero. Such a null point may occur when an RFID device passes directly over a magnetic-field coupling element that is substantially orthogonal to the magnetic-field coupling element. FIG. 10 illustrates an electrode configuration 24 that has a electric-field coupling elements or electrodes 140 for capacitively coupling to an RFID device 120 and a magnetic-field coupling element or coil 150 for magnetically coupling to the RFID device 120. The elements 140 and 150 are coupled to respective drives 142 and 152 for providing suitable signals to the elements 140 and 150. The electrodes 140 may be used for interacting with the RFID device 120 for programming or otherwise transmitting information to the RFID device 120. Thus the electrodes 140 may be located and/or configured to have a relatively long duration interaction with the RFID device 120. The magnetic-field coupling element 150 may be used for a relatively short duration interaction with the RFID device 120, such as for testing operation of the RFID device 120. A high dielectric constant material 144 may be placed in proximity to the electric-field coupling elements 142, to increase and/or concentrate capacitive coupling between the elements 142 and the device 120. The material 144 may be placed between the elements 142 and the device 120, or elsewhere in proximity to the elements. Aluminum oxide and titanium dioxide and are examples of suitable materials for the high dielectric constant material 144. A high permeability material 154 may be placed in proximity to the magnetic-field coupling elements 152, to increase and/or concentrate magnetic coupling between the elements 152 and the device 120. The material 154 may be placed between the elements 152 and the device 120, or elsewhere in proximity to the elements. Ferrites are examples of suitable materials for the high permeability material 154. It will be appreciated that use of high dielectric constant materials and high permeability materials is not limited to the embodiment shown in FIG. 10. That is, high dielectric constant materials and/or high permeability materials may also be used in conjunction with other of the embodiments disclosed herein. It will be appreciated that systems with both magnetic and electric-field coupling may be used in other ways. One alternative approach would be to drive the magnetic field in such a way that it creates an anti-phase signal in an RFID device when the RFID device is close enough to the magnetic-coupling electrode. This may be used to specifically identify when an RFID device has finished coupling. This may be used to cease writing to an RFID device by electric-field coupling, and to trigger starting of a write or programming process for the next RFID device. It will be appreciated that the configurations in the various embodiments may be combined in various suitable ways. For example, the various electrode configurations for capacitive coupling described above with regard to FIGS. 5-7 may be combinable with magnetic coupling devices, such as described above with regard to FIG. 9. Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field The invention relates to systems and methods for preparing RFID devices. 2. Background of the Related Art Radio frequency identification (RFID) tags and labels (collectively referred to herein as “devices”) are widely used to associate an object with an identification code. RFID devices generally have a combination of antennas and analog and/or digital electronics, which may include for example communications electronics, data memory, and control logic. For example, RFID tags are used in conjunction with security-locks in cars, for access control to buildings, and for tracking inventory and parcels. Some examples of RFID tags and labels appear in U.S. Pat. Nos. 6,107,920, 6,206,292, and 6,262,292, all of which are hereby incorporated by reference in their entireties. As noted above, RFID devices are generally categorized as labels or tags. RFID labels are RFID devices that are adhesively or otherwise have a surface attached directly to objects. RFID tags, in contrast, are secured to objects by other means, for example by use of a plastic fastener, string or other fastening means. RFID devices include active tags and labels, which include a power source, and passive tags and labels, which do not. In the case of passive tags, in order to retrieve the information from the chip, a “base station” or “reader” sends an excitation signal to the RFID tag or label. The excitation signal energizes the tag or label, and the RFID circuitry transmits the stored information back to the reader. The “reader” receives and decodes the information from the RFID tag. In general, RFID tags can retain and transmit enough information to uniquely identify individuals, packages, inventory and the like. RFID tags and labels also can be characterized as to those to which information is written only once (although the information may be read repeatedly), and those to which information may be written during use. For example, RFID tags may store environmental data (that may be detected by an associated sensor), logistical histories, state data, etc. As the price of RFID devices goes down, such devices are used in a wider variety of applications. It may be desirable for some applications to put individualized visual information on the RFID device. To that end, the RFID device may include or be coupled to a label that may be printed with visual information. The visual information may be machine-readable information, or may be information intended for identification and reading by a person. An example of a system for printing information on an RFID label is the system described in International Publication No. WO 02/35463, which is incorporated by reference in its entirety. Some effort has been made in prior systems to provide encoding or programming of an RFID device in conjunction with a printing operation. Examples of such systems are those described in U.S. Pat. Nos. 6,246,326 and 6,593,853. Notwithstanding these prior devices and methods, improvements would be desirable with regard to combining printing operations with interaction with an RFID device.
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<SOH> SUMMARY OF THE INVENTION <EOH>According to an aspect of the invention, a system for preparing RFID devices includes a tester/reader that interacts with RFID devices in any through reactive coupling. The reactive coupling may be capacitive, magnetic, or a combination of both. The system may also include a printer for printing on a facestock or other layers of the RFID devices. The RFID devices may be on a roll or sheet having multiple such devices. The tester/reader may have multiple electric-field coupling elements and/or magnetic-field coupling elements, to accommodate different possible orientations of the RFID devices relative to the tester/reader. For example, the tester/reader may have multiple electrodes, such as L-shape or other non-straight electrodes Alternatively, the tester/reader may have a partially-resistive electrode with multiple drive points that may be driven with AC signals of different amplitudes and/or phases. The partially-resistive electrode may be substantially rectangular, with drive points at the corners. As another alternative, the tester/reader may have one or more magnetic-field coupling elements such as coils. According to another aspect of the invention, an RFID device preparation system includes a tester/reader for interacting with a plurality of RFID devices on a sheet or roll; and a printer for printing on a layer of the RFID devices. The tester/reader interacts with the RFID devices through reactive coupling. According to yet another aspect of the invention, a tester/reader for interacting with a plurality of RFID devices on a sheet or roll, wherein the tester/reader includes: one or more electric-field coupling elements for interacting with the RFID devices through capacitive coupling; and a signal generator coupled to the one or more electric-field coupling elements. The one or more electric-field coupling elements are configured for capacitively interacting with the RFID devices in any of a variety of orientations relative to the tester/reader. To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.
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20040701
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20071211
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20060105
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69902.0
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G06K700
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TWEEL JR, JOHN ALEXANDER
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RFID DEVICE PREPARATION SYSTEM AND METHOD
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UNDISCOUNTED
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ACCEPTED
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G06K
| 2,004
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10,883,005
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ACCEPTED
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Self-associating wireless personal area network
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Methods and apparatus are provided for automatically and autonomously forming a wireless personal area network (WPAN) from an array of intercommunicating personal area network (PAN) devices. The devices comprise first communicators associated with primary functions of the devices and second communicators coupled to the first communicators for determining a subset of the devices meeting predetermined association criteria, from which subset the first communicators form the WPAN. In a preferred embodiment, the second communicators include range measuring transceivers and processors coupled to the transceivers that cooperate to determine range and relative motion of elements within communication range of the first communicators for comparison to range and relative motion association criteria stored in one or more of the devices. Memory is desirably included for storing the association criteria. The subset of devices automatically elects a master device that communicates with the other devices of the subset to form the WPAN.
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1. A Wireless Personal Area Network (WPAN) forming element, comprising: a primary user function subsystem; and a WPAN association function subsystem coupled to the primary user function subsystem, wherein the primary user function subsystem and/or the WPAN association function subsystem interrogate one or more neighboring elements having the same or different primary user functions and automatically form a WPAN with those of the neighboring elements that satisfy predetermined association criteria. 2. The element of claim 1 further comprising memory for storing the predetermined association criteria within the element. 3. The element of claim 1 wherein the WPAN association function subsystem comprises: a processor; a unique identification means coupled to the processor; and a range measuring transceiver coupled to the processor. 4. The element of claim 3 further comprising a WPAN radio coupled to the processor and the primary user function subsystem. 5. The element of claim 3 further comprising a memory coupled to the processor. 6. The element of claim 3 wherein the range measuring transceiver measures range by means of phase difference of arrival of a radio signal. 7. A system of intercommunicating elements adapted to automatically form a Wireless Personal Area Network (WPAN) from all or part of said elements, comprising: first communicators associated with primary functions of the elements; second communicators coupled to the first communicators for determining a subset of the elements meeting predetermined association criteria, among which subset the first communicators form the WPAN. 8. The system of claim 7 wherein each second communicator comprises: a range measuring transceiver; a processor coupled to the transceiver; and wherein the range measuring transceiver and processor cooperate to determine range and relative motion of elements within communication range of the first communicators. 9. The system of claim 8 further comprising identification means uniquely identifying each intercommunicating element. 10. The system of claim 8 further comprising a memory coupled to the processor for storing the predetermined association criteria to which the range and relative motion are compared. 11. The system of claim 7 wherein the second communicators determine proximity to and relative motion of the intercommunicating elements. 12. A method for forming a Wireless Personal Area Network (WPAN) from among multiple wireless elements, comprising: identifying those wireless elements within mutual communication range; determining a subset of elements meeting predetermined association criteria from among the identified wireless elements; electing a master element from among the subset of elements; and forming a WPAN from the subset of elements with the master element. 13. The method of claim 12 further comprising before the identifying step, determining whether any wireless elements are within mutual communication range. 14. The method of claim 12 wherein the determining step comprises: measuring range and relative motion of the identified elements; and comparing the measured range and relative motion to range and relative motion association criteria; and selecting as the subset those elements whose range and relative motion meet the association criteria. 15. The method of claim 14 further comprising, prior to the selecting step, inquiring whether any of the identified elements meet the range and relative motion association criteria and if not, repeating the identifying and determining steps. 16. The method of claim 12 further comprising after the forming step, performing an identifying step to determine whether any further elements have appeared within or any previously identified devices have disappeared from mutual communication range. 17. The method of claim 12 further comprising after the forming step repeating an identifying step until a further element has appeared within or an existing element has disappeared from communication range, and then repeating the determining, electing and forming steps for the such modified group of elements within communication range. 18. The method of claim 14 wherein the comparing step comprises comparing the measured range and relative motion to range and relative motion association criteria stored within the wireless element
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CROSS-REFERENCES TO RELATED APPLICATIONS This is a continuation-in-part of application Ser. No. 10/799,063, filed Mar. 11, 2004. FIELD OF THE INVENTION The present invention generally relates to wireless communication among distributed elements, and more particularly to automatic association of such distributed elements into a wireless personal area network (WPAN). BACKGROUND OF THE INVENTION Many modern electronic devices are portable and capable of communicating with each other and various base stations using wireless signaling. Non-limiting examples are 2-way radios, telephones, headsets, bar code scanners, Global Positioning System (GPS) units, Personal Digital Assistants (PDAs), portable computers (PCs), printers, digital cameras, RF identification (RFID) tag readers/writers, chart plotters, and so forth. Sometimes, a number of these various elements may be carried by or associated with a single user or function and it is desired to mutually associate them electronically to form a wireless personal area network (WPAN). Once associated, the cooperating elements can exchange or share data by communicating directly with each other rather than indirectly via a central hub, and in general, ignore other units that may be within communication range but which are not part of the WPAN. It is known in the prior art to form such WPANs, but the association of the various elements into the WPAN had to be carried out manually. This is done, for example, by entering into each unit the identity of the other elements of the WPAN. Another way is to use a local sub-master unit as a temporary hub. The identities (IDs) of the units intended to make up the WPAN are manually entered or scanned into the sub-master and then the association information downloaded from the sub-master to each of the WPAN elements. While this approach works it suffers from a number of disadvantages among which are: it is time consuming to manually reconfigure and associate the units for a particular WPAN; the WPAN make-up is not easily changed, that is, it is static rather than dynamic; it is more complex and inflexible than is desired; and it may require that the individual elements of the WPAN consume more power. Accordingly, it is desirable to provide an improved arrangement for forming and using WPANs, especially to provide an arrangement and method capable of forming and reforming WPAN associations automatically. In addition, it is desirable that the arrangement and method be robust and inexpensive relative to the prior art and, insofar as possible, take advantage of existing technology and devices. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. BRIEF SUMMARY OF THE INVENTION An apparatus is provided for automatically and autonomously forming a wireless personal area network (WPAN) from an array of intercommunicating personal area network (PAN) devices. The devices comprise first communicators associated with primary functions of the devices and second communicators coupled to the first communicators for determining a subset of the devices meeting predetermined association criteria, from which subset the first communicators form the WPAN. In a preferred embodiment, the second communicators include range measuring transceivers and processors coupled to the transceivers that cooperate to determine range and relative motion of elements within communication range of the first communicators for comparison to range and relative motion association criteria stored in one or more of the devices. Memory is desirably included for storing the association criteria. The subset of devices automatically elects a master device that communicates with the other devices of the subset to form the WPAN. A method is provided for automatically and autonomously forming a Wireless Personal Area Network (WPAN) from a plurality of Personal Area Network (PAN) devices. The method comprises identifying those wireless devices within mutual communication range, determining a subset of wireless devices meeting predetermined association criteria from among the identified wireless devices, electing a master device from among the subset of devices, and forming the WPAN from the subset of devices with the master device. In a preferred embodiment, the determining step comprises measuring range and relative motion of the identified devices, comparing the measured range and relative motion to range and relative motion association criteria, and selecting as the subset those devices whose range and relative motion meet the association criteria. It is further desirable after the forming step to repeat an identifying step until a further device appears within or an existing device disappears from mutual communication range, and then repeating the determining, electing and forming steps for such modified group of devices within mutual communication range. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and FIG. 1 is a simplified schematic diagram of a number of wireless elements forming a WPAN and illustrating coupling thereof to a base station; FIG. 2 is a simplified schematic diagram of a single representative element of the WPAN of FIG. 1; FIG. 3 is a simplified schematic diagram of a representative relay unit of the WPAN for communicating with a base station of FIG. 1; FIG. 4 is a simplified schematic diagram of the base station of FIG. 1; FIG. 5 is a simplified flow chart of the method of the present invention according to a first embodiment; FIG. 6 is a simplified schematic diagram of a number of wireless elements according to a further embodiment of the present invention, adapted to automatically form a WPAN without involvement of a base station; FIG. 7 is a simplified schematic block diagram of a single representative wireless element of FIG. 6; and FIGS. 8A-B are simplified flow charts of the method of the present invention according to further embodiments. DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention. FIG. 1 is a simplified schematic diagram of system 20 comprising a number of wireless elements 22, 24, 26, 28 forming WPAN 40 within spatial boundary 42 and illustrating coupling of WPAN 40 to base station 35 via main hub 36 and other elements 32, 34. For simplicity, the various antennas associated with elements 22, 24, 26, 28, 30, 32, 34, 36 needed to provide communication over wireless links 23, 25, 27, 29, 31, 33 are omitted from FIG. 1. However, persons of skill in the art will understand that antennas are included with the various wireless communication elements. For convenience of explanation, it is assumed that elements 22, 24, 26, 28 and 30, 32, 34 are in close proximity and able to mutually communicate at lower power and, perhaps, relatively higher speed over wireless links 23, 25, 27, 29 using, for example, the well-known Bluetooth® protocol. However, this is not intended to be limiting and any convenient shorter range (SR), lower power (LP) communication protocol (abbreviated collectively as “SR-LP”) may be used. Elements 34 and 36 mutually communicate via wireless link 33 at longer range and at higher power but, perhaps, relatively lower speed using, for example, the 802.11 signaling protocol. However, this is not intended to be limiting and any signaling protocol capable of transferring the necessary information may be used. As used herein, the term longer range (LR), higher power (HP), abbreviated collectively as “LR-HP”, is intended to generally refer to such a communication system irrespective of the particular construction or signaling protocol used. Alternatively, wireline communication link 53 may be provided between server 38 and relay 34 instead of or in addition to wireless link 33 between elements 34, 36. Thus, in the preferred embodiment, at least two communication links are desirably used: (1) a SR preferably LP link among the various distributed elements 22, 24, 26, 28 and 30, 32, 34 and, (2) a LR preferably HP link (e.g., link 33) or a wireline link (e.g., link 53) between at least one of the distributed elements (e.g., element 34) and a base station (e.g., base station 35 of FIG. 1) that includes or is coupled to a central server. Bluetooth is a non-limiting example of a suitable SR-LP communication arrangement and 802.11 is a non-limiting example of a LR-HP communication arrangement, but neither is essential and other signaling protocols and arrangements may also be used. Non-limiting examples of alternative signaling protocols and arrangements are Zigbee™ and Ultra-Wideband (UWB) for which industry working groups have been formed. As will be more fully explained later other alternatives exist for communication link 33. For example, where separate signal relay 34 does not exist, this function can be assumed by one of the WPAN devices capable of acting as a master unit. Bluetooth also provides a LR-LP signaling protocol as well as the more typical SR-LP signaling protocol. Elements 22, 24, 26, 28 30, 32, 34 illustrate different types of wireless elements that may be in simultaneous use in the same general area. For example, and not intended to be limiting, element 22 can be a personal computer (abbreviated as “PC”), element 24 a cell phone (abbreviated as “CELL”) perhaps with an included digital still or video camera, element 26 a 1-way or 2-way pager (abbreviated as “PAG”), element 28 a wrist mounted communicator or watch or compass or GPS unit or a combination thereof (abbreviated as “WRIST”), element 30 a bar code reader (abbreviated as “BCR”), element 32 a personal digital assistant (abbreviated as “PDA”) and element 34 a printer, which in this example also functions as a remote relay. These particular examples are provided merely for convenience of explanation and are not intended to be limiting. Any type of electronic device may be utilized in place of or in addition to the elements illustrated herein. As will be subsequently explained in more detail, elements 22-32 form ad-hoc network 44 within boundary 46, in that they are all within mutual SR-LP communication range of each other. PDA 32 is illustrated as being able to communicate with remote relay (e.g., printer) 34 and thereby provides a gateway for any of devices 22-30 to address remote relay (e.g., printer) 34, and in turn use remote relay 34 as a communication bridge for sending or receiving information from base station 35 via LR-HP wireless communication link 33 or alternatively via wireline communication link 53. Persons of skill in the art will understand that remote relay 34 is identified as a printer merely for convenience of explanation and that remote relay 34 may have any other function in addition to its dual mode communication relay function providing both wireless SR-LP communication link 31 or wireline communication link 53 and LP-HP communication link 33. Where devices 44 are generally located in a predetermined area, such as for example, but not limited to a warehouse, storage yard, shipping facility or the like, then devices having a reasonably even distribution in the facility are good candidates for remote relay 34. Non-limiting examples are water coolers, vending machines, photocopiers, image scanners, wall telephones and so forth. Such devices are typically connected to the facility power lines or phone lines or both and wireline communication therewith can be easily provided, for example, using Ethernet™ or Power-over-Ethernet (e.g., IEEE 802.3af) or other convenient wireline protocol or arrangement. In these circumstances wireless communication link 33, while possible, is not essential and wireline communication link 53 is convenient. In the prior art, WPAN 40 would have been formed by manually entering the WPAN identification data for the elements within outline 42 into the various elements or by using a barcode ring scanner with Bluetooth coupling to scan the identification code of the local master (e.g., element 32) for subsequent direct association. In the present invention, each of elements 22, 24, 26, 28, 30, 32, 34 has an RF identification tag (RFID) function included therein, that may be addressed by base station 35 using wireless communication paths 51, 51′ to determine their individual location relative to base station 35. Within base station 35 are main hub transceiver 36 and location server 38 which determine the current location of elements 22, 24, 26, 28, 30, 32, 34 using any convenient RFID location technique. It does this in substantially real time. Non-limiting examples of suitable real time location system (RTLS) technologies are received signal strength indication (RSSI), time difference of arrival (TDOA) and phase difference of arrival (PDOA). These provide location information by triangulation using multiple transmitters or receivers. U.S. Pat. No. 6,414,626 B1, for example, describes an arrangement for measuring RFID tag range using a single transceiver operating at multiple frequencies. Range data from multiple transceivers may be used to provide location data. This is merely an example of many ways known in the art for obtaining location data using RFID tags or RFID functions. Any suitable position locating technology may be employed by main hub 36 and server 38 to determine the position of elements 22, 24, 26, 28, 30, 32, 34. These technologies can employ reflective back scattering for position location and need not rely on active signal transmission from elements 22, 24, 26, 28, 30, 32, 34. Thus, elements 22, 24, 26, 28, 30, 32, 34 need not transmit higher power signals for this purpose. This greatly simplifies many of elements 22, 24, 26, 28, 30, 32, 34 and reduces their power consumption. However, the use of locating signal transmitters on such elements is not precluded. Once the locations of these elements are known, then server 38 determines which subsets should logically form one or more WPANs. Server 38 then creates an association table. The association table is transmitted, for example, to elements 22, 24, 26, 28 via remote relay element 34 using LR-HP communication link 33 or wireline link 53. Element 34 then relays the information to element 32 and elements 22, 24, 26, 28 using, for example, Bluetooth over wireless links 31, 29. Thereafter, units 22, 24, 26, 28 for example, mutually communicate with each other as shown by wireless paths 25, 27 and with elements 32 (and through 32 to 34) as shown by wireless paths 29, 31 using SR-LP communication links 31, 29, 27, 25. Server 38 can logically determine which elements should form a WPAN using any number of predetermined and/or adaptive criteria. Non-limiting examples of such criteria are: (a) associating elements that are within spatial boundary 42 of a predetermined size and/or shape, and/or (b) associating elements that are within spatial boundary 42 for a predetermined time t=t1, and/or (c) associate elements that move together substantially as a group for a predetermined time t2. Adaptive criteria may also be used, for example, tracking the whereabouts of elements 22, 24, 26, 28 relative to element 32 and/or element 34 and associating those elements that are within a predetermined distance of elements 32 and/or 34, and then repeating such associating steps periodically after time intervals t=t3. The duration of t3 may be made smaller or larger depending upon the rate of change of relative position of the elements, that is, their re-association may be carried out more or less frequently depending upon how rapidly the relative locations of the associated elements change with respect to each other and/or to their communication links 32, 34. The size of spatial boundary 42 and time durations t1, t2, t3 may be stored in memory 41 coupled to server 38 by link 39, or at any other convenient location in system 20. While element 32 is identified in the forgoing explanation as being outside of WPAN 40 but close enough so that it can relay the Bluetooth signals from elements 22, 24, 26, 28 of WPAN 40 to remote relay element 34, this is merely to illustrate a more general situation. Element 32 could equally well be a part of WPAN 40 if it satisfies the desired association criteria. Similarly, element 30 while also in Bluetooth communication range of some or all of elements 22, 24, 26, 28 but not a part of WPAN 40 could also be a part of WPAN 40, depending upon the association criteria applied by server 38. An advantage of the present invention is that the signals 51, 51′ generally used to identify the elements to be associated and signals 33 (and/or wireline link 53) to transmit the association table, for the most part, need not be encrypted, thereby simplifying the signaling system. Once the various elements have been associated into WPAN 40, then the SR-LP (e.g., Bluetooth) signals being exchanged over wireless paths 25, 27 within WPAN 40 and paths 29, 31 with links 32, 34 may be encrypted so that data security is maintained. The low radiated power of the SR-LP signals among elements 22, 24, 26, 28, 30, 32, 34 also aids in privacy. The following is an example of the application of the invented means and method to a military, public safety or rescue person carrying a number of sensors and other devices. Assume that the person enters the unit equipment locker or equipment storage place and loads up with equipment needed for a particular mission. The equipment may be worn or carried by the person on the mission. Such equipment can include some or all of the following: a helmet mounted communication headset, a GPS position locator, a heartbeat monitor, a temperature monitor, a two-way radio, a data telemetry link, a “Hazmat” environmental hazards monitor, a chart display, night vision goggles, a personal position locator, an oxygen or air tank pressure monitor, fire-arm, multi-purpose flashlight, etc., each of which is equipped with an RFID transponder and SR-LP communication capability or equivalent. The local equivalent of base station 35 of FIG. 1 determines, using the RFID techniques mentioned above or equivalent, that the above-listed elements are located within a very small spatial envelope (e.g., on the person's body or equipment harness) and moving together (when he or she moves they all move). Accordingly, it determines that they should form a WPAN. Other equipments located within the storage space is not included within this WPAN because they do not move as a group. Base station 35 then transmits the corresponding association table to whichever of the elements being carried by the person is acting as the signal relay (equivalent to element 34) and local master (e.g., element 32). If a signal relay does not exist in the WPAN, then any master device can satisfy this requirement as long as it is within range of base station 35 by using a SR-LP or LR-LP link with the base station. For example, Bluetooth has LR-LP link capability as well SR-LP link capability and the LR-LP link can be used instead of the 802.11 LR-HP link. The signal relay and local master in turn instruct each associated element to intercommunicate using their built-in SR-LP communication protocol (e.g., Bluetooth) and what addresses to use to send critical status data (e.g., heart rate, Hazmat data, temperature, oxygen tank pressure, etc.) via the relay or other link back to base station 35 or another monitor point located in the field where the mission will be carried out. The user needs to do nothing to form his or her WPAN. It is accomplished automatically as he or she chooses his or her personal instrumentation package and moves within or about or exits from the equipment storage location. The elements in a particular WPAN can maintain their associated status without interference from other WPANs even when the other WPANs are within signal transmission range. This is possible because each element of the WPAN has a unique ID that can be included in the SR-LP transmission so that other elements in that WPAN and the relay link(s) respond in general only to direct signals from within the designated WPAN. Signals can be exchanged between different WPANs via relay links 32, 34 to a central monitoring point (e.g., base station 35 or equivalent in a field location). However, persons of skill in the art will understand that inter-WPAN communication elements can be included in a WPAN to permit certain signals to be exchanged directly among nearby WPANs if that is desired. FIG. 2 is a simplified schematic diagram of single representative element 60 of WPAN 40 of FIG. 1, illustrating the basic features thereof. Element 60 includes host 62, SR-LP communicator 64 and RFID tag function 66. Host 62 provides any of the functions previously listed (e.g., PC, PDA, CELL, PAG, WRIST, BCR, Hazmat detector, temperature sensor, pressure sensor, GPS, etc.) or any others that may be desired. SR-LP communicator 64 is preferably but not essentially a Bluetooth communicator with, for example, link controller 641 coupled to HOST 62 by link or bus 621, CPU core 642 coupled to link controller 641 and radio transceiver 643 by link or bus 644. Antenna 645 is coupled to radio 643 for sending and receiving the SR-LP signals generated by communicator 64. A booklet entitled “Bluetooth Beginner's Guide” explaining how a Bluetooth communicator functions may be obtained from the North American Headquarters of Ericsson, Inc., Plano, Tex. As explained therein, Bluetooth devices are capable of self-organizing, that is, of forming ad-hoc local networks with other Bluetooth devices within signal communication range, e.g., ad-hoc network 48 of devices 44 within outline 46 of FIG. 1. One (or more) of the elements within ad-hoc network 48 will act as a local “master” and the others will be “slaves”. In addition to automatically forming ad-hoc network 48, the local master will look for a communication link (e.g., link 33) to a base station (e.g., base station 35) able to provide an association table to define a WPAN (e.g., WPAN 40) from among the ad-hoc network elements (e.g., from among elements 44). $$ RFID tag 66 is shown as a separate part within element 60, but this is merely for convenience of explanation. It may be coupled to HOST 62 by link or bus 661 and/or to SR-LP communicator 64 by bus or link 662, but this is not essential. The function of RFID tag 66 is to receive “Who are you?—Where are you?” signals 51 from base station 35 and transmit responses 51′ so that base station 35 may locate RFID tag 66 (and therefore potential WPAN element 60) and track its movement. Suitable RFID tags are commercially available. While RFID tag 66 is shown in FIG. 2 as being an independent element, this is not essential and not intended to be limiting. In general the transponder function provided by RFID tag 66 may be stand-alone or coupled to or integrated either in HOST 62 and/or communicator 64. All three arrangements are useful. The ability to use a stand-alone RFID tag permits any Bluetooth equipped electronic device to be quickly added to the possible list of automatic association WPAN elements by merely attaching a stand-alone RFID tag and using it in conjunction with system 20 of the present invention. This is a great convenience. Alternatively, the RFID tag function may be integrated with other electronic functions of element 60. Either arrangement is useful. FIG. 3 is a simplified schematic diagram of remote relay unit 70 whereby WPAN 40 can communicate with server 38 of base station 35. In FIG. 1, element 34 is shown as providing the remote relay function. However, any of elements 22, 24, 26, 28, 30, 32, 34 can be configured to perform this function. Hence remote relay unit 70 of FIG. 3 is intended to illustrate further details of element 34 or any other element that is selected to perform the communications relay function. Relay element 70 conveniently comprises HOST 72 (in the case of element 34, HOST 72 was a printer, but this is not essential). HOST 72 is analogous to HOST 62 of FIG. 2 and can be any of the elements discussed in connection with FIG. 2, or such other elements as the user may need. It may also be any of the facilities units (water coolers, telephones, copiers, etc.) mentioned earlier. HOST 72 is coupled by bus or link 721 to SR communicator 74 with antenna 745, analogous to communicator 64 with antenna 645 of FIG. 2. This provides the first communication mode of relay 70, i.e., the SR (e.g., Bluetooth) link. Also coupled to bus or link 721 is LR communicator 78 with antenna 785. Communicator 78 provides the second communication mode of relay 70, i.e., the LR (e.g., the 802.11 link). Alternatively, communicator 78 may provide the LR link by communicating with base station 35 over wireline link 53 instead of or in addition to communicating via antenna 785. Either arrangement is useful. Communicators 74, 78 may exchange signals via bus or link 721 or via direct bus or link 79. Either arrangement is useful. Either of communicators 74, 78 may act as the master controller. Among other things, a function of relay 70, 34 is to pass signals from elements 44 of ad-hoc network 48 to base station 35 and vice versa, and pass the association table generated by base station 35 back to selected members of ad-hoc network 48 so they know which should associate to form WPAN 40. Once WPAN 40 has been formed, relay 70, 34 can pass messages back and forth between base station 35 (or its field equivalent) and the members of WPAN 40. FIG. 3 illustrates the situation whereby element 78 provides a LR wireless link such as an 802.11 link or wireline link via bus or leads 53, but this is not essential. Provided that relay 70 is within range of or coupled to base station 35, any link protocol or arrangement can be used. For example, Bluetooth has a LR-LP wireless link capability that enables any master unit to function as a signal relay. Thus, element 78 in relay 70 may also be a Bluetooth protocol device using the LR-LP Bluetooth mode for communicating with base station 35. As noted earlier, element 78 may also communicate with base station 35 over wireline link 53 if available. Persons of skill in the art will understand that the present invention is not limited to the particular signaling protocols or arrangements or the particular signal relays illustrated herein. What is important is that at least one remote device be available to provide a communication link between WPAN capable devices 44 and base station 35. RFRID tag 76 may optionally be included in relay 70 communicating with data links 74, 78 over leads or bus 762 and to host 72 via leads or bus 761, FIG. 4 is a simplified schematic diagram of base station 35 of FIG. 1, providing further details. Base station 35 automatically determines the locations of elements 22-32, decides which should be associated and sends the resulting association table to the WPAN elements. Base station 35 can also perform other functions in support of WPAN 40. Base station 35 comprises main hub transceiver 36, location server 38, and memory 41. Location server 38 comprises processor 381 coupled via link or bus 383 with I/O 382. Processor 381 is coupled via link or bus 39 to memory 41. I/O 382 is coupled via links or buses 371, 371 to main hub transceiver 36. Where remote relay 34 is substantially fixed, I/O 382 may also be coupled to remote relay 34 via wireline bus or link 53, but this is not essential. Main hub transceiver 36 comprises transmitter 361 with antenna 368 and, for example, receivers 362, 363, 364 with antennas 365, 366, 367. I/O 382 is coupled to transmitter 361 via link or bus 371. Receivers 362-364 are coupled to I/O 382 via bus or link 372. Transmitter 361 and receivers 362-364 operate under the control of processor 381. Transmitter 361 sends via antenna 368 outgoing wireless signal 51 that is received by RFID tag 52. Tag 52 represents RFID tags 66, 76 (or integrated tag functions) and any others carried by elements 22, 24, 26, 28, 30, 32, 34 of FIG. 1. Each of tags 52 responds either by backscatter modulation of incoming transmission 51 if it is a passive tag or by generation of a suitable response if it is an active tag, and sends wireless response signals 531-533 back to base station 35. Signals 531-533 are the same signals that follow different spatial paths back to receivers 362-364. Response signals 531-533 are received, for example, by spatially distributed antennas 365-367. Differences in time and/or phases of arrival of signals 531-533 are used by processor 381 in cooperation with receivers 362-364 to determine the ranges from tags 52 to the different antennas 365-367. These range differences permit the spatial locations of tags 52 to be determined by processor 381. While the arrangement shown in FIG. 4 is suitable for determining the location of tags 52, persons of skill in the art will understand that this is merely exemplary and that any other suitable location determining means may also be used. Once the locations of various tags 52 (e.g., 22, 24, 26, 28, etc.) have been determined, processor 381 in cooperation with memory 41 determines which should be associated into a WPAN using the methods previously described. Base station 35 then sends the association table using wireless communication link 33 and/or wireline communication link 53 to remote relay 34, 70, through which it is sent on to elements 22, 24, 26, 28, etc., desired to be associated in the WPAN. As previously explained, wireless communication link 33 may use 802.11 or Bluetooth or any other convenient signaling protocol that can be understood by whatever remote device is functioning as the relay. Persons of skill in the art will also understand based on the description herein that the term “RFID tag” or “tag” is not intended to be limited to a discrete RFID tag but to include those RFID functions that may be integrated with other portions of the electronics of the particular element of which they are a part. While base station 35 is illustrated in FIG. 4 as comprising a single processor and transmitter with multiple spaced-apart receivers, this is merely for convenience of explanation and persons of skill in the art will understand based on the description herein that any real time location system (RTLS) arrangement may be used, for example and not intended to be limiting, multiple transmitters and a single receiver, multiple transmitters with multiple receivers, and so forth. Further, and not intended to be limiting, transmitter 361 can be a multi-function transmitter able to provide position locating signals 51 as well as information transmitting signals 33 using various signaling protocols, (e.g., 802.11, Bluetooth, Zigbee™, Ultra Wideband (UWB), etc.), or separate transmitters may also be used. Either arrangement is suitable. What is important is that base station 35 be able to determine the location of the individual potential WPAN elements so that it can, by either their real time proximity or proximity as a function of time or cooperative movement or other useful criteria or a combination thereof, decide which to associate into a WPAN and then send that association information to the WPAN elements. A non-limiting example of other useful criteria is the situation where certain PAN capable elements are used in pairs. Suppose that related elements A and B (e.g., a remote headset and a portable transceiver) are found in ad-hoc network 48 and only one meets, for example, the current proximity criteria, nevertheless, both may be included in the WPAN because they are part of a cooperating pair. FIG. 5 is a simplified flow chart of the method 100 of the present invention according to a preferred embodiment. Method 100 comprises steps 102 initiated primarily by RTLS server 38 of base station 35 and steps 120 initiated primarily in the array of potential personal area network (PAN) capable devices (e.g., elements 22, 24, 26, 28, 30, 32, 34, etc.). Referring now to steps 102, START 103 desirably but not essentially occurs on system power-up. LOCATE POTENTIAL PAN ELEMENTS step 104 is executed whereby base station 35 locates the individual PAN elements using, for example the RFID tag functions incorporated therein, as has been previously explained in connection with FIGS. 1-4. FETCH AND APPLY WPAN ASSOCIATION CRITERIA step 106 is then executed, wherein the WPAN association criteria discussed earlier and stored in memory 41 are retrieved by server 38 and applied to the location data determined in step 104. It should be noted that the fetch operation can be performed before or after step 104 for locating the potential PAN elements. Once the location data and the association criteria are available, server 38 can determine which of available PAN elements 44 conform to the association criteria (e.g., are within a predetermined spatial boundary 42 and/or move as a group, etc.) so as to be desirably formed into WPAN 40. The particular association criteria used may depend upon the choices of the system designer or user according to the type of PAN elements likely to be encountered. In BUILD WPAN ASSOCIATION TABLE step 108, the results of step 106 are used to form the association table so that it is ready to be transmitted to the elements of WPAN 40. As used herein the words “association table” are not intended to refer merely to a columnar table of data. These words are intended to generally include any data form or data format for transmitting information about which devices should associate to form the WPAN, and whatever other information is needed for the WPAN to form and function. Thus, as used herein, the words “association table” are intended to have such broad meaning. TABLE CHANGED? query 110 is then desirably but not essentially executed to determine whether the association table determined in step 108 has changed from that determined in the last iteration of steps 102. If the outcome of query 110 is NO (FALSE) then steps 102 of method 100 loop back to start 103 as shown by path 111. Query 110 is desirable to conserve power in the WPAN elements by not signaling them when there is no change in the WPAN association table. Referring now to steps 120 that begin with START 121, which occurs automatically when multiple PAN capable devices are active and within communication range of each other. In step 122 potential PAN devices 44 (e.g., 22, 24, 26, 28, 30, 32, 34, etc.) exchange signals under the direction of link controllers or CPU cores 641 using radios 643 (see FIG. 2) with each other, i.e., with all PAN capable devices 44 within communication range, so that any new (previously unidentified) PAN capable elements are noted. In the course of this exchange, certain PAN elements will publish themselves as master(s). The remainder are slaves. In step 124, for example following the Bluetooth protocol, the various PAN capable devices or elements exchange sufficient information to form ad-hoc network 48 of PAN capable devices 44 within mutual communication range, including any new PAN capable devices that had not been noted in previous iterations of steps 120. PAN DEVICES CHANGED? query 126 is then desirably but not essentially executed wherein it is determined whether the ad-hoc network of PAN devices formed in step 124 contains new members not previously noted in the last iteration of steps 120. If the outcome of query 126 is NO (FALSE) then steps 120 of method 100 loop back to start 121 as shown by path 127. This is desirable to conserve power in wireless elements 44 under circumstances where no new members are detected by eliminating the need to signal to base station 35 to report “no change.” If the outcome of query 126 is YES (TRUE), then in step 128, ad-hoc network 48 formed by PAN capable devices 44 uses remote relay 34, 70 to identify and connect via main hub transceiver 36 or wireline link 53 or alternate communication path to RTLS server 38 of base station 35, looking for an association table. Where a particular remote relay 34, 70 is not available, any master WPAN device can function as the relay provided that it is in communication range with base station 35. RTLS server 38 and ad-hoc network 48 exchange information as indicated by arrows 140, 142 so that RTLS server 38 can determine in step 112 (e.g., via relay 34, 70 or equivalent) whether or not PAN elements 44 are connected and ready to receive a WPAN association table. Similarly, PAN elements 44 can interrogate RTLS server 38 to determine in query 130 whether a WPAN association table is ready, or alternately RTLS server 38 tells PAN elements 44 that the WPAN association table is ready to be transmitted. Thus, query 130 is desirable but not essential. If the outcome of either query 112, 130 is NO (FALSE) then method 100 loops back as shown by paths 113, 131 until both the WPAN association table is ready and potential PAN elements 44 are coupled to server 38. When the outcome of query 112 is YES (TRUE) and the WPAN association table is ready, then in step 114, RTLS 38 sends the WPAN association table via base hub transmitter 36 or wireline link 53 and remote relay 34 (or an equivalent PAN master) to the elements within outline 42 telling them that they should associate as WPAN 40. This is indicated in method 100 of FIG. 5 by signal 140 coupling SEND TABLE step 114 in step sequence 102 and RECEIVE TABLE step 132 in step sequence 120. Signal 140 preferably complies with the 802.11 signaling standard, but other signaling protocols can be used depending upon the circumstances and/or whether wireline link 53 is available. This association information is automatically transmitted to the elements (e.g., 22, 24, 26, 28) intended to make up WPAN 40. Human intervention is not needed. As indicated in step sequence 120, the elements within outline 42 use the WPAN association table received in step 132 to execute step 134 wherein these elements form a secure WPAN and operate together. In the preferred embodiment but not essentially, REFRESH TIME RUN? queries 116, 136 are executed following SEND TABLE step 114 and FORM SECURE WPAN step 134. In queries 116, 136 it is determined whether predetermined iteration times have elapsed. If the outcomes of queries 116, 136 are NO (FALSE) indicating that it is not yet time to repeat steps 102, 120, then these queries are repeated as indicated by paths 115, 135 respectively. If the outcomes of queries 116, 136 are YES (TRUE) then method 100 loops back to START 102, 120 as indicated by paths 117, 137 respectively. The iteration delay times associated with queries 116, 136 may be the same or different according to the needs of the particular application of method 100. The instructions needed to execute step sequence 102 is conveniently stored in memory 41 and executed by server 38. The hardware and stored instructions needed to execute step sequence 120 are conveniently provided within communicator 64. In the case of the Bluetooth protocol, commercially available hardware can be micro-programmed to execute program sequence 120. Persons of skill in the art will understand how to do this based on the teachings herein and the available Bluetooth standards. One of the advantages of the present invention is that it can be implemented with minimum development and cost by use of, for example, the Bluetooth standard. This significantly simplifies deployment of system 20 according to the present invention. FIG. 6 is a simplified schematic diagram of system 148 comprising a number of PAN wireless elements 178 according to a further embodiment of the present invention, adapted to automatically form a WPAN without involvement of a base station. System 148 has, by way of example, and not intended to be limiting, first group 150 comprising wireless elements 153, 154, 156 that intercommunicate as indicated by arrows 151, 153, 155, and second group 160 comprising wireless elements 156, 162, 164 that intercommunicate as indicated by arrows 161, 163, 165, and third group 170 comprising, for example, wireless elements 172, 174 that intercommunicate as indicated by arrow 173. Element 156 is common to both groups 150, 160. Groups 160 and 170 intercommunicate as indicated by arrow 171. The elements illustrated in groups 150, 160, 170 are merely exemplary and not intended to be limiting. For example, element 152 can be a two-way pager (abbreviated PAG), 154 can be a bar code reader (abbreviated BCR), element 156 can be a cell phone (abbreviated CELL), element 162 can be a wrist mounted communicator or vital signs monitor or both (abbreviated WRIST), element 164 can be a personal computer-like device (abbreviated PC), element 172 can be a personal digital assistant (abbreviated PDA) and element 174 can be a label or document printer or equivalent (abbreviated PRN), and so forth. The present invention is not limited to these particular elements, and the elements illustrated are merely by way of example and are not intended to be limiting, but rather to generally represent any kind of elements that can be usefully associated into a wireless personal area network (WPAN). In the present example, elements 152, 154, 156 of group 150 are in communication range of each other as are elements 156, 162, 164 of group 160. But only element 156 is in communication range to provide communication between groups 150, 160. Similarly, element 162 is able to communicate with element 172 of group 170, but not directly with element 174 of group 170. Suppose by way of example that it is desirable to determine whether any or some or all of these elements should associate to form a WPAN and do so without the aid of a central monitor or server, such was used in connection system 20 of FIG. 1. By providing elements having the capabilities illustrated in FIGS. 7 and 8, this can be accomplished. Elements 152, 154, 156, 162, 164, optional element 172 and further optional element 174 are collectively referred to as personal area network (PAN) elements 178. One of more of these elements may be capable of communicating with a central server or network and may act as a bridge on behalf of other elements of the WPAN after it is formed, but this is not essential for the present invention. FIG. 7 is a simplified schematic block diagram of single representative element 180 of PAN candidates 178 of FIG. 6. FIGS. 8A-B illustrate method 200, 200′ carried out by system 148 of FIG. 6 and element 180 of FIG. 7. Referring now to FIG. 7, element 180 represents any of candidate PAN elements 178. Each element 180 has primary function or subsystem 181 and WPAN association function or subsystem 182. Primary function or subsystem 181 can be any of those functions illustrated above (e.g., BCR, PAG, CELL, PC, WRIST, PDS, PRN) and/or any other function. WPAN association function or subsystem 182 allows some or all of elements 178 to identify each other, select a master element and associate into a WPAN if they meet predetermined association criteria. WPAN association function or subsystem 182 conveniently comprises range-measuring transceiver 184 with antenna 183, device unique identification (ID) 186, WPAN radio 188 with antenna 187, processor 190 and memory 192. Range measuring transceiver 184 can include RFID tag components that are addressable by other PAN elements 178. Elements 181, 184, 186, 188, 190, 192 are conveniently coupled by bus or leads 185. Processor 190 and memory 192 may also or alternatively have direct memory access (DMA) bus or connection 191. WPAN association function or subsystem 182 is illustrated as comprising individual elements or functions 184, 186, 188, 190, 192, but this is merely for convenience of explanation and not intended to be limiting. Persons of skill in the art will understand based on the description herein that any or all of the individual functions represented by elements 184, 186, 188, 190, 192 may be integrated within primary function 181 or elsewhere in device or element 180. For example, and not intended to be limiting, the function of range measuring transceiver 184 and WPAN radio 188 may be combined, or either or both may be combined with a transceiver contained within primary function 181. Likewise, processor 190 and/or memory 192 may be part of primary function 181. What is important is that element 180 is capable of performing the functions described herein not whether they are performed by separate circuits or elements. The operation of subsystem or function 182 will be more fully understood in connection with the discussion of flow charts 200, 200′ of FIGS. 8A-B. A wireless personal area networks (WPAN) is generally formed from multiple elements that have something in common, as for example, they are in close proximity to each other and/or they move as a group or both and/or they are functionally related (e.g., a headset and its transceiver). For example, a public safety officer, a military person or a rescue worker may conveniently carry a variety of equipment that should be associated in a WPAN. Non-limiting examples of such equipment are communication headsets, communication transceivers, environmental monitors, vital signs monitors, breathing gas tanks and regulators, data transceivers, position locators, audio or visual direction displays and/or maps, and so forth. A warehouse worker may carry a bar-code reader, a label printer, a data communicator, a personal communicator, an inventory tracker, and so forth. These personnel not only carry some or all of this equipment as they perform their duties, but also may come within communication range of other equipment that is in the neighborhood but not a part of their kit. Thus, the WPAN association function must be able to automatically select the proper elements to make up the worker's WPAN and ignore those that are merely in communication range but not associated with the worker's WPAN function. WPAN association criteria are conveniently stored in memory 192 and used by subsystem or function 182 to select those elements that should form the WPAN based on these predetermined association criteria. The WPAN association criteria may be the same as those already discussed in connection with system 20 and FIGS. 1-5 or may be different depending upon the needs of the user. For convenience of explanation it is assumed in the discussion of FIGS. 6-8 that proximity and collective movement are the preferred association criteria. But, persons of skill in the art will understand based on the description herein that other association criteria can also be used. As used herein, the words “association criteria” are intended to include whatever criteria may be selected by the system designer or user and not be limited merely to the examples provided herein. FIGS. 8A-B are simplified flow charts 200, 200′ of the method of the present invention according to further embodiments. Flow charts 200. 200′ perform substantially the same function but differ in detail. Referring now to FIG. 8A, method 200 begins with START 202 that desirably occurs when the individual PAN elements or devices (e.g., represented by typical element 180) are powered up. Then is step 210 WPAN radios 188 and/or range measuring transceivers 184 in cooperation with ID elements 186, of various candidate PAN elements 178, identify and exchange ID's with those elements within communication range. Persons of skill in the art will know how this is accomplished, using for example, the Bluetooth, Zigbee or other wireless protocol discussed earlier. In step 220, range-measuring transceiver 184 (in cooperation with processor 190) determines the subset of PAN devices from among those identified in step 210 that meet the association criteria (e.g., suitable range, collective motion, signal strength, etc.). In the preferred embodiment, range and relative motion are determined, for example, by using RFID phase difference of arrival (PDOA) measurements. PDOA provides the best present current positional accuracy (e.g., about 1 meter or better), but any suitable system maybe used. Any ranging system capable of accuracies within the signal communication range of various PAN candidate elements or devices 178 may be sued. By making a series of ranging measurements correlated with the unique ID of each element, processor 190 can determine which of PAN candidate elements 178 are moving as a group. Those elements that satisfy the association criteria stored in memory 192, for example, those that are close together and move as a group, are identified as the subset of PAN candidates that should be associated into the WPAN. In the preferred embodiment, each element 180 of the PAN candidates 178 determines, with respect to the other elements within its communication range: (a) Its mutual physical proximity to the other PAN candidate devices; (b) The signal strength or communication channel robustness to/from the other PAN candidate devices; and (c) Whether it is substantially stationary or moving with respect to the other PAN candidate devices. In the preferred embodiment, individual elements 180 within PAN candidate group 178 share their discovery list with each other and, preferably, include their relative signal strength, communication channel robustness and relative motion. Some of elements 178 will have different discovery lists. For example, elements within group 150 will have a discovery list that differs from those in groups 160 and 170 and vice versa. Similarly, the relative signal strength of signaling paths 151, 153, 155, 161, 163, 165, 171, 173 will also likely differ. The relative motion results will differ for those WPAN candidate elements that are not moving with the rest. In step 230 a master element is “elected”, that is, determined from among the identified subset of PAN elements. For example, those elements with the largest number of associations should nominate themselves to be the master element of the WPAN network. This capability is well known in the Bluetooth, Zigbee and other wireless environments. If there is a tie for two or more masters, then various arbitration criteria may be used to declare a winner. For example, the device with the highest total signal strength across the intercommunicating devices is a desirable master element. Alternatively, the device that is able to intercommunicate directly with the largest number of subset devices is also a possible master element or device. If there continues to be a tie, then the tied devices can select a random number and decide which will be the network master based on the highest (or lowest) random number value chosen by the various candidate master elements. Random number selection continues until only one device is left, which then designates itself the master and announces its “election” to the other WPAN candidate devices of the subset. The foregoing method of election of a master element is merely exemplary and not intended to be limiting. Various other criteria can also be used, for example, and not intended to be limiting, overall device capability, functionality, memory size, power consumption, battery capacity and so forth. Such factors (and others) may be given various weightings in the scoring process used to select the master element. Persons of skill in the art will understand how to choose the optimum master selection protocol depending upon the types of devices generally intended to form the WPAN. The appropriate protocol is conveniently stored in memory 192 of candidate devices 178 so that they are able to automatically and autonomously form the WPAN by following the steps of method 200, 200′. Each device 180 locates and identifies the other device(s) with which it can communicate, and determines whether or not it should associate therewith based on the association criteria stored in memory 192, e.g., predetermined proximity, duration of relative proximity, relative motion, and/or other such other criteria as the user or system designer may select. Selection criteria may be based on specific application needs of a particular user. For example, if a wearable head-set device is seeking a connection to a wide area network to make a cell phone call instead of a local area network to make a voice over internet protocol (VoIP) call, but none of the associated WPAN devices are capable of cellular network connection, then that device may on its own temporarily seek connection through ad-hoc network bridging to another device outside of the normal WPAN that does have this capability. For example, WPAN 160 of FIG. 6 can link over path 171 to WPAN 170 which may be capable of providing voice service to WPAN 160. After electing the master device in step 230, then in step 240, the subset of elements whose situation meets the association criteria discussed above associate to form a secure WPAN and method 200 loops back to START 202, as shown by path 247, or proceeds to END 250 on power-down. As used herein in connection with choosing or designating a master device or element from among the various PAN devices, the words “elect” and “electing” are intended to include any means or method for accomplishing this selection and the examples given above are not intended to be limiting. Method 200′ of FIG. 8B illustrates substantially the same process flow as method 200 of FIG. 8A but adds additional details. The same reference numbers are used in method 200′ for substantially the same steps as in method 200. Referring now to FIG. 8B, following START 202 (e.g., on power-up), method 200′ proceeds to LOCAL DEVICES DETECTED? query 208 wherein each element 180 determines (e.g., using subsystem or function 182) whether or not there are one or more other candidate PAN devices within communication range. If the outcome of query 208 is NO (FALSE), abbreviated as “N”, then method 200′ loops back to START 202 and step 208 is repeated until a YES (TRUE), abbreviated “Y”, is obtained, whereupon method 200′ proceeds to step 210. In step 210 method 200′ identifies the local devices that it has found (e.g., obtains their unique IDs) from function 186. In FIG. 8B, step 220 is sub-divided into steps 222, 224, 226. In step 222, subsystem 182 determines the proximity and/or relative motion and/or signal strength as previously noted. Then, DO SOME MEET ASSOCIATION TEST? query 224 is executed wherein it is determined whether or not some of the identified devices satisfy the association criteria stored in memory 192. If the outcome of query 224 is NO (FALSE) then method 200′ loops back to step 210 as shown by path 221 and steps 210, 222, 224 are repeated until step 224 yields a YES (TRUE) outcome. When the outcome of query 224 is YES (TRUE) then the subset of identified devices that meet the association criteria are chosen in step 226 as the WPAN candidates and the other PAN elements not meeting the association criteria are henceforth ignored. In step 230, the master device is elected and in step 240 the secure WPAN is formed, as already discussed in connection with method 200. The master device performs the function of controlling the ad-hoc network communications within the WPAN and any external communication links to a base station and/or other WPANs. Then, LOCAL DEVICES CHANGED? query 242 is desirably but not essentially executed wherein it is determined whether or not further or different or fewer devices are now in communication proximity. Stated another way, identification query 242 determines whether a further device has appeared within communication range and/or whether an existing device has dropped out of communication range. If the outcome of query 242 is NO (FALSE) then method 200′ loops back as shown by path 243 and step 242 is repeated until a YES (TRUE) outcome is obtained whereupon, as shown by path 245, method 200′ returns to step 220 to determine, for example, the proximity, relative motion and signal strength of the modified group of element(s). Steps 222, 224, 226, 230, 240 are repeated. The elements that continue to meet the association criteria are retained in the WPAN, elements that no longer meet the association criteria or are no longer detected are dropped and any newly acquired elements meeting the association criteria are added to the WPAN. Method 200′ repeats as described above as long as the various elements are powered-up. The advantages of the arrangement of FIGS. 6-8 are that the WPAN is automatically and autonomously formed (and re-formed) from the available candidate PAN elements without manual intervention and without the need for a central base station. These are particular features of this embodiment of the present invention. Element proximity, collective movement and other association criteria are determined locally using the capabilities of the candidate PAN elements themselves without depending upon a central monitoring and position determining station. This is a significant advantage in many circumstances where the WPAN association needs to take place in the field away from a central monitoring station. Many such situations exist where availability of a WPAN is important, as for example, for disaster rescue, military operations, law enforcement, medical emergencies, and so forth, that occur in unpredictable and changing locations where there is often no infrastructure and no central monitor site, even though one or more of the elements (e.g. a cell phone) may provide a communication link to a network. The present invention is particularly well adapted to provide WPANs under such circumstances and is therefore, very useful. The foregoing description of the present invention assumes that each of candidate PAN devices 178 has the elements or functions of representative device 180, but it is not essential that each candidate device be equally capable as far as the functions described in connection with representative device 180 is concerned. For example, a separate range measuring function may not be needed in all of elements 178. For example, where their communication range is extremely short, the presence/absence of a communication signal may be sufficient to establish sufficient range information and in these circumstances range measuring transceiver 184 is not essential. If such potential WPAN elements can measure signal strengths from others, for example, using WPAN radio 188 and processor 190, and how the signal strengths change with time, such elements may determine which elements are in their vicinity and moving as a group. While this may not be as accurate as the output from range measuring transceiver 184, it can provide sufficient information to compare to the association criteria stored in memory 192. Thus, while it is preferred that each potential WPAN element include range-measuring transceiver 184, this is not essential. All that is needed in most circumstances is that PAN elements 178 be able to determine proximity within a comparatively small range and identify collective movement. Thus, significant variation of functional capabilities may be tolerated among PAN elements 178, i.e., they need not all have every sub-element of device 180, and still be able to participate in forming a WPAN in the manner generally described herein. While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Many modern electronic devices are portable and capable of communicating with each other and various base stations using wireless signaling. Non-limiting examples are 2-way radios, telephones, headsets, bar code scanners, Global Positioning System (GPS) units, Personal Digital Assistants (PDAs), portable computers (PCs), printers, digital cameras, RF identification (RFID) tag readers/writers, chart plotters, and so forth. Sometimes, a number of these various elements may be carried by or associated with a single user or function and it is desired to mutually associate them electronically to form a wireless personal area network (WPAN). Once associated, the cooperating elements can exchange or share data by communicating directly with each other rather than indirectly via a central hub, and in general, ignore other units that may be within communication range but which are not part of the WPAN. It is known in the prior art to form such WPANs, but the association of the various elements into the WPAN had to be carried out manually. This is done, for example, by entering into each unit the identity of the other elements of the WPAN. Another way is to use a local sub-master unit as a temporary hub. The identities (IDs) of the units intended to make up the WPAN are manually entered or scanned into the sub-master and then the association information downloaded from the sub-master to each of the WPAN elements. While this approach works it suffers from a number of disadvantages among which are: it is time consuming to manually reconfigure and associate the units for a particular WPAN; the WPAN make-up is not easily changed, that is, it is static rather than dynamic; it is more complex and inflexible than is desired; and it may require that the individual elements of the WPAN consume more power. Accordingly, it is desirable to provide an improved arrangement for forming and using WPANs, especially to provide an arrangement and method capable of forming and reforming WPAN associations automatically. In addition, it is desirable that the arrangement and method be robust and inexpensive relative to the prior art and, insofar as possible, take advantage of existing technology and devices. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
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<SOH> BRIEF SUMMARY OF THE INVENTION <EOH>An apparatus is provided for automatically and autonomously forming a wireless personal area network (WPAN) from an array of intercommunicating personal area network (PAN) devices. The devices comprise first communicators associated with primary functions of the devices and second communicators coupled to the first communicators for determining a subset of the devices meeting predetermined association criteria, from which subset the first communicators form the WPAN. In a preferred embodiment, the second communicators include range measuring transceivers and processors coupled to the transceivers that cooperate to determine range and relative motion of elements within communication range of the first communicators for comparison to range and relative motion association criteria stored in one or more of the devices. Memory is desirably included for storing the association criteria. The subset of devices automatically elects a master device that communicates with the other devices of the subset to form the WPAN. A method is provided for automatically and autonomously forming a Wireless Personal Area Network (WPAN) from a plurality of Personal Area Network (PAN) devices. The method comprises identifying those wireless devices within mutual communication range, determining a subset of wireless devices meeting predetermined association criteria from among the identified wireless devices, electing a master device from among the subset of devices, and forming the WPAN from the subset of devices with the master device. In a preferred embodiment, the determining step comprises measuring range and relative motion of the identified devices, comparing the measured range and relative motion to range and relative motion association criteria, and selecting as the subset those devices whose range and relative motion meet the association criteria. It is further desirable after the forming step to repeat an identifying step until a further device appears within or an existing device disappears from mutual communication range, and then repeating the determining, electing and forming steps for such modified group of devices within mutual communication range.
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20040630
|
20080722
|
20050915
|
98576.0
| 0
|
PHAM, TUAN
|
SELF-ASSOCIATING WIRELESS PERSONAL AREA NETWORK
|
UNDISCOUNTED
| 1
|
CONT-ACCEPTED
| 2,004
|
|||
10,883,077
|
ACCEPTED
|
Re-entrant cavity fluorescent lamp system
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An electrodeless fluorescent lamp (10) having a burner (20), a ballast housing (30) containing a ballast (40) and a screw base (50) for connection to a power supply. A reentrant cavity (60) is formed in the burner (20) and an amalgam receptacle (70) containing amalgam (75) is formed as a part of the reentrant portion and in communication with the burner (20). A housing cap (80), formed of a suitable plastic, connects the burner (20) to the ballast housing (30) and a suitable adhesive (31) fixes the burner to the housing cap (80). An EMI cup (90) is formed as an insert to fit into the ballast housing (30), which also is formed of a suitable plastic, and has a bottom portion (100) and an EMI cap (110) with an aperture (120) therein closing an upper portion (140). The EMI cup (90) and the EMI cap (110) are preferably formed from 0.5 mm brass. The amalgam receptacle (70) extends through the aperture (120) and into the cup (90). For a fixed amalgam position, changing the aperture size allows adjustment of the amalgam tip temperature, and thus, allows control of the system lumen output, efficacy, CCT and CRI, all of which are dependent on the amalgam temperature.
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1. In an electrodeless fluorescent lamp having a burner, a ballast housing containing a ballast and a base for connection to a power supply, the improvement comprising: a reentrant cavity in said burner; an amalgam receptacle in communication with said burner; a housing cap connecting said burner to said ballast housing; an EMI cup formed as part of said ballast housing, said EMI cup having a bottom portion and having a cap with an aperture therein closing an upper portion, said amalgam receptacle extending through said aperture and into said ballast housing. 2. The electrodeless fluorescent lamp of claim 1 wherein a ferrite tube is positioned in said reentrant cavity. 3. The electrodeless fluorescent lamp of claim 2 wherein said EMI cup contains a ballast board containing ballast components, said ballast board being positioned adjacent said bottom portion and a gasket positioned adjacent said upper portion, said gasket holding said ballast board in place and providing cushioning for axial shocks to said lamp. 4. The electrodeless fluorescent lamp of claim 3 wherein said EMI cup contains an annular centering ring surrounding said ballast board and including an inwardly extending flange upon which said ballast board rests for maintaining a fixed distance between a bottom of said ballast board and said bottom portion of said EMI cup. 5. The electrodeless fluorescent lamp of claim 4 wherein said EMI cup contains a ballast heat sink applied in a viscous state to encompass surface mount components on said bottom of said ballast board whereby electrical isolation and thermal contact are formed to provide cooling of the ballast on said ballast board.
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CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority from Provisional Patent Application Ser. No. 60/519,143 filed Nov. 12, 2003. TECHNICAL FIELD This invention relates to fluorescent lamps and more particularly to electrodeless fluorescent lamps. Still more particularly, it relates to such lamps having a reentrant cavity. BACKGROUND ART As market forces call for more efficient fluorescent lamps to be smaller and more incandescent in shape, conventional electroded fluorescent lamp faces difficult hurdles. The A-shaped bulb that covers conventional electroded discharges causes an approximately 8% lumen decrease due to reflection loss. The gas separation between the electroded lamp's tubular phosphor layer (where the heat is generated) and the A-shaped outer covering (where heat escapes the system) leads to inherently higher system temperatures. Higher temperatures lead to significant problems in producing higher lumen (e.g., >15 W, 800 lumen), A-shaped electroded systems. Electrodeless fluorescent discharge lamps have solved many of the problems associated with the previous attempts to market compact fluorescent lamps. The discharge chamber can be made in the A-shape so there is no need for an outer covering. The phosphor is on the A-shape portion of the lamp so cooling is more effective. Such compact electrodeless lamps have been on the market for some time and basically comprise two different types; one type being an inductively driven plasma discharge with a separate ballast; and the other being an integrally ballasted, inductively driven discharge. The latter type of electrodeless discharge lamp works well generally; however, it presents some problems with heat, inadequate RF shielding for some uses, and inadequate temperature control for the amalgam. DISCLOSURE OF INVENTION It is, therefore, an object of the invention to obviate the disadvantages of the prior art. It is another object of the invention to enhance the operation of electrodeless fluorescent lamps. Yet another object of the invention is a fluorescent lamp having better amalgam temperature control. Still another object of the invention is the provision of an electrodeless fluorescent lamp with good RF shielding at a reasonable cost. These objects are accomplished, in one aspect of the invention, by the provision of an electrodeless fluorescent lamp having a burner, a ballast housing containing a ballast and a base for connection to a power supply. A reentrant cavity is provided in the burner and an amalgam receptacle is in communication with the burner. A housing cap connects the burner to the ballast housing and there is an EMI cup formed as part of the ballast housing. The EMI cup has a bottom portion and a cap with an aperture therein closing an upper portion. The amalgam receptacle extends through the aperture and into the ballast housing, which helps to regulate the amalgam temperature. The ballast housing provides superior RF shielding allowing multiple uses of the lamp in places previously unavailable. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of an embodiment of the invention, partially in section; and FIG. 2 is an enlarged sectional view of the ballast housing of the invention. BEST MODE FOR CARRYING OUT THE INVENTION For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in conjunction with the above-described drawings. Referring now to the drawings with greater particularity, there is shown in FIG. 1 an electrodeless fluorescent lamp 10 having a burner 20, a ballast housing 30 containing a ballast 40 and a screw base 50 for connection to a power supply. A reentrant cavity 60 is formed in the burner 20 and an amalgam receptacle 70 containing amalgam 75 is formed as a part of the reentrant portion and in communication with the burner 20. A housing cap 80, formed of a suitable plastic, connects the burner 20 to the ballast housing 30 and a suitable adhesive 31 fixes the burner to the housing cap 80. An EMI cup 90 is formed as an insert to fit into the ballast housing 30, which also is formed of a suitable plastic, and has a bottom portion 100 and an EMI cap 110 with an aperture 120 therein closing an upper portion 140. The EMI cup 90 and the EMI cap 110 are preferably formed from 0.5 mm brass. The amalgam receptacle 70 extends through the aperture 120 and into the cup 90. For a fixed amalgam position, changing the aperture size allows adjustment of the amalgam tip temperature, and thus, allows control of the system lumen output, efficacy, CCT and CRI, all of which are dependent on the amalgam temperature. A coupler in the form of a wire-wrapped a ferrite tube 150 is positioned in the reentrant cavity 60 and includes a thermally insulating coupler cap 152 and a coupler base 154 formed of ceramic paper containing high purity alumina based refractory fibers, such as Rescor 300 available from Cotronics Corporation. Kapton tape may be used to secure the wire wrapping at the top and bottom of the ferrite core. A burner housing insulation 155 is fitted into the reentrant portion and also serves to support the ferrite core. Housing insulation 155 is preferably made from black nylon. A flange 156 centers the housing insulation 155 within the ballast housing 30. The EMI cup 90 contains a ballast board 160 containing ballast components 170, and the ballast board is positioned adjacent the bottom portion 100 of the cup 90 and a gasket 180 is positioned adjacent the upper portion 140 of the cup 90 and against the cap 110. The gasket 180 holds the ballast board 160 in place and provides cushioning for axial shocks to the lamp 10. The gasket 180 is preferably constructed of silicone foam rubber. The EMI cup 90 additionally contains an annular centering ring 190 that is preferably formed from nylon and that surrounds the ballast board 160 and includes an inwardly extending flange 200 upon which the ballast board 160 rests for maintaining a fixed distance between a bottom 210 of the ballast board 160 and the bottom portion 100 of the EMI cup 90. The EMI cup 90 also contains a ballast heat sink 220 that is applied in a viscous state to encompass surface mount components on the bottom 210 of the ballast board 160, whereby both electrical isolation and thermal contact are formed to provide cooling of the ballast 40 on the ballast board 160. In a preferred embodiment of the invention the ballast heat sink is comprised of a thermally conductive epoxy and 5 to 6 grams of Sylgard 165, available from Dow Corning. A DC board 230 can be positioned in the screw base 50 and is insulated from the EMI cup 90 by an insulating disc 235 of, preferably, Nomex, about 0.005 inches thick. Apertures, such as 240 in the EMI cap 110 and 241 in the bottom 100 of EMI cup 90, are provided to allow the threading of the necessary connecting wires. There is thus provided an electrodeless fluorescent lamp having minimal interference with nearby electrical appliances due to its RF shielding and with excellent amalgam temperature control. While there have been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modification can be made herein without departing from the scope of the invention as defined by the appended claims.
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<SOH> BACKGROUND ART <EOH>As market forces call for more efficient fluorescent lamps to be smaller and more incandescent in shape, conventional electroded fluorescent lamp faces difficult hurdles. The A-shaped bulb that covers conventional electroded discharges causes an approximately 8% lumen decrease due to reflection loss. The gas separation between the electroded lamp's tubular phosphor layer (where the heat is generated) and the A-shaped outer covering (where heat escapes the system) leads to inherently higher system temperatures. Higher temperatures lead to significant problems in producing higher lumen (e.g., >15 W, 800 lumen), A-shaped electroded systems. Electrodeless fluorescent discharge lamps have solved many of the problems associated with the previous attempts to market compact fluorescent lamps. The discharge chamber can be made in the A-shape so there is no need for an outer covering. The phosphor is on the A-shape portion of the lamp so cooling is more effective. Such compact electrodeless lamps have been on the market for some time and basically comprise two different types; one type being an inductively driven plasma discharge with a separate ballast; and the other being an integrally ballasted, inductively driven discharge. The latter type of electrodeless discharge lamp works well generally; however, it presents some problems with heat, inadequate RF shielding for some uses, and inadequate temperature control for the amalgam.
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<SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>FIG. 1 is an elevational view of an embodiment of the invention, partially in section; and FIG. 2 is an enlarged sectional view of the ballast housing of the invention. detailed-description description="Detailed Description" end="lead"?
|
20040701
|
20061010
|
20050512
|
80246.0
| 0
|
VO, TUYET THI
|
RE-ENTRANT CAVITY FLUORESCENT LAMP SYSTEM
|
UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,883,083
|
ACCEPTED
|
Coil antenna
|
A coil antenna is disclosed comprising a magnetic core and a wire wound around the magnetic core. The magnetic core is flexible and bendable and is made of a mixture comprising soft magnetic powder and an organic binder agent. The soft magnetic powder comprises a plurality of particles each of which is coated with an insulator layer.
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1. A coil antenna comprising a magnetic core and a wire wound around the magnetic core, wherein: the magnetic core is flexible and bendable and is made of a mixture comprising soft magnetic powder and an organic binder agent; and the soft magnetic powder comprises a plurality of particles each of which is coated with an insulator layer. 2. The coil antenna according to claim 1, wherein the magnetic core has a plate-like shape, a sheet-like shape, or a string-like shape. 3. The coil antenna according to claim 1, wherein the magnetic core is obtainable by, under the normal atmospheric pressure, casting or molding and curing or hardening the mixture. 4. The coil antenna according to claim 1, wherein the organic binder agent is a plastomer agent. 5. The coil antenna according to claim 1, wherein the organic binder agent is an elastomer agent. 6. The coil antenna according to claim 5, wherein the organic binder agent is thermoplastic resin. 7. The coil antenna according to claim 6, wherein the organic binder agent is made of polyester resin, polyvinyl chloride resin, chlorinated polyethylene, polyvinyl butyral resin, polyurethane resin, cellulosic resin, polyvinyl acetate resin, phenoxy resin, polypropylene, polycarbonate resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, polyvinyl alcohol resin, polyimide resin, polyethylene resin, polyamide resin, polyacrylic ester resin, or polyacrylonitrile resin, or copolymer thereof. 8. The coil antenna according to claim 5, wherein the organic binder agent is thermosettable resin. 9. The coil antenna according to claim 8, wherein the organic binder agent is made of epoxy resin, phenol resin, amide resin, imide resin, diallyl phthalate resin, unsaturated polyester resin, melamine resin, urea resin, or silicone resin, or a combination thereof. 10. The coil antenna according to claim 5, wherein the organic binder agent is synthetic rubber. 11. The coil antenna according to claim 10, wherein the organic binder agent is made of nitrile-butadiene rubber, styrene-butadiene rubber or a combination thereof. 12. The coil antenna according to claim 1, wherein the soft magnetic powder is Fe carbonyl powder, ferrite powder, pure iron powder, powder made of Fe—Si—Al alloy, Fe—Ni alloy, Fe—Co alloy, Fe—Co—Si alloy, Fe—Si—V alloy, Fe—Co—B alloy, Co base amorphous metal, Fe base amorphous metal, or Mo-permalloy, or a combination thereof. 13. The coil antenna according to claim 1, wherein a mixing ratio of the organic binder in the mixture is in a range of from 5 percents, by weight, to 40 percents, by weight, both inclusive, and another mixing ratio of the soft magnetic powder in the mixture is in a range of from 60 percents, by weight, to 95 percents, by weight, both inclusive. 14. The coil antenna according to claim 1, wherein the mixture further comprises an organic flame retardant. 15. The coil antenna according to claim 14, wherein the organic flame retardant is made of halogenide, bromide polymer or a combination thereof. 16. The coil antenna according to claim 1, wherein the soft magnetic powder comprises a plurality of flat particles. 17. The coil antenna according to claim 16, wherein each of the flat particles has an aspect ratio of 5 or more. 18. The coil antenna according to claim 1, wherein the insulator layer is made of non-magnetic material. 19. The coil antenna according to claim 18, wherein the insulator layer is made of an oxide film. 20. The coil antenna according to claim 18, wherein the insulator layer is made of an organic binder agent. 21. A radio transmitting/receiving system which is transmittable/receivable radio signals ranging from 10 kHz to 5 MHz and which comprises the coil antenna according to claim 1 so as to transmit/receive the radio signals. 22. A radio controlled wristwatch comprising: the coil antenna according to claim 1; and a mechanism for automatically adjusting a time in accordance with radio signals received by using the coil antenna. 23. The radio controlled wristwatch according to claim 22, further comprising a case and a watchband depending therefrom, wherein the coil antenna is provided for the watchband. 24. The radio controlled wristwatch according to claim 22, further comprising a case and a watchband depending therefrom, wherein: the case comprises a bottom plane and a peripheral wall; and the magnetic core is curved within a plane parallel to the bottom plane and extends along an inside of the peripheral wall. 25. A remote keyless entry system comprising the coil antenna according to claim 1, wherein the coil antenna is for receiving user identification signals, which are transmitted from an object carried by a user. 26. A vehicle adopting the remote keyless entry system according to claim 25, wherein the coil antenna is embedded within the vehicle. 27. The vehicle according to claim 26, wherein the coil antenna is contained in a door handle of the vehicle.
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BACKGROUND OF THE INVENTION This invention relates to a coil antenna used for transmitting and/or for receiving radio signals within a low or medium frequency band. Specifically, the target frequencies of the radio signals range from 10 kHz to 5 MHz. There have been used or proposed various kinds of apparatuses, systems, or terminals, which transmit and/or receive radio signals of low or medium frequencies. A typical, well-known system is an AM (amplitude modulation) radio system. A relatively new system is a radio controlled timepiece, especially, a radio controlled wristwatch. Other relatively new system is an immobilizer for vehicle, a remote keyless entry system for vehicle or for house, or an RFID system. For more is information about a radio controlled wristwatch, see U.S. Pat. No. 6,134,188, which is incorporated herein by reference in its entirety. For more information about a remote keyless entry system for vehicle, see U.S. Pat. No. 6,677,851, which is incorporated herein by reference in its entirety. An important component common to the above-mentioned apparatuses or the like is an antenna, especially, a coil antenna which comprises a magnetic core and a coil wound around the magnetic core. For example, an already-existing magnetic core for coil antenna is made of a sintered ferrite core or a laminated core consisting of amorphous metal sheets. The former is easily breakable and does not have flexibility on design because of its hardness. The latter is not easily machinable and is expensive so that its manufacturing cost becomes high. An improved coil antenna is disclosed in JP-A 2001-337181, which is incorporated herein by reference in its entirety. The disclosed coil antenna is used for a radio controlled timepiece or wristwatch and has a core comprised of powder particles or flakes of ferrite or metal and a plastic binder agent. The core may hold another harder core, such as a sintered ferrite core or a laminated core made of amorphous metal sheets. The core comprised of JP-A 2001-337181 possesses high impact resistance because of its softness and can be readily formed with low cost. SUMMARY OF THE INVENTION Inventors of the present invention could recognize that, in JP-A 2001-337181, there was a preconception which impeded large improvement of a coil antenna in its design flexibility. The preconception was that a core for coil antenna was not allowed to be bent flexibly. Since there was the preconception, nobody could consider a possibility of a flexible, bendable, magnetic core for coil antenna. Accordingly, it was not considered what structure was suitable for the flexible, bendable, magnetic core. The present invention removes the above-mentioned preconception and provides a coil antenna comprising a magnetic core which has suitable structure for being bent flexibly. According to an aspect of the present invention, a coil antenna comprises a magnetic core and a wire wound around the magnetic core, wherein: the magnetic core is flexible and bendable and is made of a mixture comprising soft magnetic powder and an organic binder agent; and the soft magnetic powder comprises a plurality of particles each of which is coated with an insulator layer. Because each of the power particles is coated with the insulator layer, the coil antenna according to the aspect of the present invention has a superior μ′ characteristic on a frequency range of from 10 kHz to 5 MHz even if the coil antenna is bent while being used and even if the coil antenna is kept in the bent state. An appreciation of the objectives of the present invention and a more complete understanding of its structure may be had by studying the following description of the preferred embodiment. DESCRIPTION OF PREFERRED EMBODIMENTS An embodiment of the present invention has two different coil antennas. One of them is for signal transmission, while the other is for signal reception. Each of the coil antennas comprises a magnetic core and a wire wound around the magnetic core. Each of the magnetic cores is made of a mixture comprising soft magnetic powder and an organic binder agent and is formed to be flexible and bendable. The soft magnetic powder comprises a plurality of particles each of which is coated with an insulator layer. In this embodiment, each of the magnetic cores is formed in a plate-like shape In detail, the magnetic core for signal transmission has a size of 8×8×60 mm3, and the wire for 10 T is wound thereon. The magnetic core for signal reception has a size 2×10×60 mm3, and the wire for 100 T is wound thereon. Each of the wires is a polyurethane enameled copper wire. Each of the magnetic cores of the plate-like shapes is formed by stacking a plurality of sheet-like shaped magnetic cores thinner than the magnetic core of the plate-like shape. According to the forming method, a large press machine is not required for making a large sized magnetic core. Also, a complicated mold or die is not required for making a magnetic core of a complicated shape, because the sheet-like shaped magnetic core can be easily cut by the use of a cutter or a pair of scissors. The magnetic core may have a string-like shape. Each of the magnetic cores of the present embodiment is obtained by, under the normal atmospheric pressure, casting or molding and curing or hardening the above-mentioned mixtures of the soft magnetic powder and the organic binder agent. The compression molding and the injection molding are not required to obtain the magnetic cores of the present embodiment. In this embodiment, the coil antenna for signal transmission and the other coil antenna for signal reception are similar to each other, except for their size and their magnetic flux density of the wires as mentioned above. Now, explanations will be made of the common matters. The soft magnetic powder of this embodiment is Fe—Si—Al alloy powder, especially, Sendust powder, wherein Fe, Si, Al are 84%, 10%, 6%, respectively. The soft magnetic powder may be other powder. For example, the soft magnetic powder may be Fe carbonyl powder, ferrite powder, or pure iron powder. The soft magnetic powder may be powder made of Fe—Si—Al alloy, Fe—Ni alloy (Permalloy), Fe—Co alloy, Fe—Co—Si alloy, Fe—Si—V alloy, Fe—Co—B alloy, Co base amorphous metal, Fe base amorphous metal, or Mo-permalloy. Also, the soft magnetic powder may be a combination of the above-mentioned powders. In this embodiment, the soft magnetic powder comprises flat particles. In more detail, each of the flat particles has an aspect ratio of 5 or more and its diameter is about 35 μm. In this embodiment, the insulator layer is made of non-magnetic material, especially, an oxide film. The oxide film of this embodiment is formed in an annealing process for the soft magnetic powder. The oxide film may be obtained by another means or way. The insulator layer may be made of an organic binder agent. The organic binder agent of the present embodiment is chlorinated polyethylene. A titanate coupler is added to the organic binder in this embodiment. Alternatively, a silane coupler or an aluminate coupler may be used. Also, no coupler may be used. The organic binder agent may be made of another elastomer agent. For example, the organic binder agent may be thermoplastic resin, such as resin made of polyester resin, polyvinyl chloride resin, chlorinated polyethylene, polyvinyl butyral resin, polyurethane resin, cellulosic resin, polyvinyl acetate resin, phenoxy resin, polypropylene, polycarbonate resin, ABS (acrylontrile-butadiene-styrene copolymer) resin, polyvinyl alcohol resin, polyimide resin, polyethylene resin, polyamide resin, polyacrylic ester resin, or polyacrylonitrile resin, or copolymer thereof. The organic binder agent may be thermosettable resin, such as resin made of epoxy resin, phenol resin, amide resin, imide resin, diallyl phthalate resin, unsaturated polyester resin, melamine resin, urea resin, or silicone resin, or a combination thereof. Alternatively, the organic binder agent may be synthetic rubber, such as nitrile-butadiene rubber, styrene-butadiene rubber or a combination thereof. Furthermore, the organic binder agent is a plastomer agent, provided that it can provide a flexible, bendable, magnetic core. Another coupling agent can be added to the organic binder. In this embodiment, the mixing ratio of the soft magnetic power is 80 wt %, and the total mixing ratio of the organic binder agent and the coupler is 20 wt %. The mixing ratio of the soft magnetic powder in the mixture may be in a range of from 60 wt % to 95 wt %, both inclusive. The mixing ratio of the organic binder in the mixture may be in a range of from 5 wt % to 40 wt %, both inclusive. If a coupler added thereto, the mixing ratio of the coupler in the mixture is 5 wt % or less. The mixture may further comprise an organic flame retardant, such as an organic flame retardant made of halogenide, bromide polymer or a combination thereof. To evaluate the coil antennas for signal transmission and for signal reception in accordance with the present embodiment, the above-mentioned coil antennas were formed, and their characteristics were measured. As comparative examples, two coil antennas were formed of sintered ferrite cores and wires wound thereon; one of the comparative coil antenna was for signal transmission, while the other was for signal reception. The comparative coil antennas had the same structures, shapes, sizes as those of the embodiment except for the materials of the magnetic cores. The characteristics of the comparative coil antennas were also measured. The measured results are as follows. Each of the magnetic cores of the present embodiment had rubber hardness degree of 60 or more, which was measured by using type-A durometer in accordance with JIS K 6253. JIS is an abbreviation of “Japan Industrial Standard”, and JIS K 6253 is entitled “Hardness testing methods for rubber, vulcanized or thermoplastic”. The magnetic core of the present embodiment had a tensile strength of 3.8 MPa, which was measured in accordance with JIS K 6263. The JIS K 6263 is entitled “Rubber, vulcanized or thermoplastics—Determination of stress relaxation”. The coil antenna for signal transmission and the coil antenna for signal reception had superior transmission and reception characteristics in comparison with the comparative coil antenna for signal transmission and the comparative coil antenna for signal reception. In addition, the superior transmission and reception characteristics were kept even when the coil antennas were bent. This is because the particles of the magnetic powder are separated from and independent of each other and work as “micro-cores”, respectively. The number of the micro-cores does not change even when the coil antenna is bent because each of the particles is coated with the oxide film. The above-mentioned coil antenna is applicable to a radio transmitting/receiving system which is transmittable/receivable radio signals ranging from 10 kHz to 5 MHz. For example, the above-mentioned coil antenna is applicable to a radio controlled wristwatch, which further comprises a mechanism for automatically adjusting a time in accordance with radio signals received by using the coil antenna. Specifically, the radio controlled wristwatch comprises a case and a watchband depending therefrom. The coil antenna may be embedded in the watchband. Alternatively, the magnetic core may be curved within a plane parallel to the bottom plane of the case and extends along an inside of the peripheral wall of the case. Furthermore, the coil antenna of the present embodiment is applicable to a remote keyless entry system, wherein the coil antenna is for receiving user identification signals, which are transmitted from an object carried by a user. In case where a vehicle adopts the remote keyless entry system, the coil antenna may be embedded within the vehicle. More specifically, the coil antenna may be contained in a door handle of the vehicle. The preferred embodiments of the present invention will be better understood by those skilled in the art by reference to the above description and figures. The description and preferred embodiments of this invention illustrated in the figures are not to intend to be exhaustive or to limit the invention to the precise form disclosed. They are chosen to describe or to best explain the principles of the invention and its applicable and practical use to thereby enable others skilled in the art to best utilize the invention. While there has been described what is believed to be the preferred embodiment of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the sprit of the invention, and it is intended to claim all such embodiments that fall within the true scope of the invention. This application is based on Japanese Patent Application filed on Jul. 2, 2003, No. 2003-270331, and those claims, specification and drawings are incorporated herein by reference.
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<SOH> BACKGROUND OF THE INVENTION <EOH>This invention relates to a coil antenna used for transmitting and/or for receiving radio signals within a low or medium frequency band. Specifically, the target frequencies of the radio signals range from 10 kHz to 5 MHz. There have been used or proposed various kinds of apparatuses, systems, or terminals, which transmit and/or receive radio signals of low or medium frequencies. A typical, well-known system is an AM (amplitude modulation) radio system. A relatively new system is a radio controlled timepiece, especially, a radio controlled wristwatch. Other relatively new system is an immobilizer for vehicle, a remote keyless entry system for vehicle or for house, or an RFID system. For more is information about a radio controlled wristwatch, see U.S. Pat. No. 6,134,188, which is incorporated herein by reference in its entirety. For more information about a remote keyless entry system for vehicle, see U.S. Pat. No. 6,677,851, which is incorporated herein by reference in its entirety. An important component common to the above-mentioned apparatuses or the like is an antenna, especially, a coil antenna which comprises a magnetic core and a coil wound around the magnetic core. For example, an already-existing magnetic core for coil antenna is made of a sintered ferrite core or a laminated core consisting of amorphous metal sheets. The former is easily breakable and does not have flexibility on design because of its hardness. The latter is not easily machinable and is expensive so that its manufacturing cost becomes high. An improved coil antenna is disclosed in JP-A 2001-337181, which is incorporated herein by reference in its entirety. The disclosed coil antenna is used for a radio controlled timepiece or wristwatch and has a core comprised of powder particles or flakes of ferrite or metal and a plastic binder agent. The core may hold another harder core, such as a sintered ferrite core or a laminated core made of amorphous metal sheets. The core comprised of JP-A 2001-337181 possesses high impact resistance because of its softness and can be readily formed with low cost.
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<SOH> SUMMARY OF THE INVENTION <EOH>Inventors of the present invention could recognize that, in JP-A 2001-337181, there was a preconception which impeded large improvement of a coil antenna in its design flexibility. The preconception was that a core for coil antenna was not allowed to be bent flexibly. Since there was the preconception, nobody could consider a possibility of a flexible, bendable, magnetic core for coil antenna. Accordingly, it was not considered what structure was suitable for the flexible, bendable, magnetic core. The present invention removes the above-mentioned preconception and provides a coil antenna comprising a magnetic core which has suitable structure for being bent flexibly. According to an aspect of the present invention, a coil antenna comprises a magnetic core and a wire wound around the magnetic core, wherein: the magnetic core is flexible and bendable and is made of a mixture comprising soft magnetic powder and an organic binder agent; and the soft magnetic powder comprises a plurality of particles each of which is coated with an insulator layer. Because each of the power particles is coated with the insulator layer, the coil antenna according to the aspect of the present invention has a superior μ′ characteristic on a frequency range of from 10 kHz to 5 MHz even if the coil antenna is bent while being used and even if the coil antenna is kept in the bent state. An appreciation of the objectives of the present invention and a more complete understanding of its structure may be had by studying the following description of the preferred embodiment. detailed-description description="Detailed Description" end="lead"?
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20040701
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20070123
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20050203
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63407.0
| 0
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CABUCOS, MARIE G
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COIL ANTENNA
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,883,101
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ACCEPTED
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Web server apparatus and method for virus checking
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A web server computer system includes a virus checker and mechanisms for checking e-mails and their attachments, downloaded files, and web sites for possible viruses. The virus checker allows a web server to perform virus checking of different types of information real-time as the information is requested by a web client. In addition, a web client may also request that the server perform virus checking on a particular drive on the web client. If this case, the web server may receive information from the web client drive, scan the information for viruses, and inform the web client whether any viruses were found. In the alternative, the web server may download a client virus checker to the web client and cause the client virus checker to be run on the web client. The preferred embodiments thus eliminate the need for virus checking software to be installed on each web client.
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1. A web server computer apparatus comprising: (A) at least one processor; (B) a memory coupled to the at least one processor; (C) a virus checker application residing in the memory; and (D) a virus control mechanism residing in the memory and executed by the at least one processor, the virus control mechanism: determining whether a request for information from a web client to the web server computer apparatus requires virus checking; if the request for information does not require virus checking, sending the requested information to the web client; if the request requires virus checking, invoking the virus checker application to check the requested information for a virus; if the requested information contains a virus, notifying the web client that the requested information contains a virus; if the requested information does not contain a virus, sending the requested information to the web client. 2. The apparatus of claim 1 wherein the virus control mechanism determines whether a request for information from a web client to the web server computer apparatus requires virus checking by examining defined user virus checking preferences to determine whether the request for information requires virus checking. 3. The apparatus of claim 1 wherein the virus control mechanism performs the steps of: warning the user when the requested information contains a virus; prompting the user to select whether to receive the information that contains the virus; if the user selects to receive the requested information notwithstanding the virus, sending the requested information to the client; if the user selects to not receive the requested information, discarding the requested information. 4. The apparatus of claim 1 further comprising the steps of: downloading a client version of a virus checker application to the web client; and causing the client version of the virus checker application to be executed on the web client to check for viruses on the web client. 5. The apparatus of claim 1 wherein the virus control mechanism notifies at least one authority when a virus is detected. 6. The apparatus of claim 1 wherein the virus control mechanism includes a user feedback mechanism for a user to input information to the virus control mechanism regarding a virus. 7. A method for a web server to service a request for information from a web client, the method comprising the steps of: (A) determining whether the request requires virus checking; (B) if the request does not require virus checking, sending the requested information to the web client; (C) if the request requires virus checking, checking the requested information for a virus; (D) if the requested information contains a virus, notifying the web client that the requested information contains a virus; (E) if the requested information does not contain a virus, sending the requested information to the web client. 8. The method of claim 7 wherein step (A) is performed by examining defined user virus checking preferences to determine whether the request for information requires virus checking. 9. The method of claim 7 further comprising the steps of: warning the user when the requested information contains a virus; prompting the user to select whether to receive the information that contains the virus; if the user selects to receive the requested information notwithstanding the virus, sending the requested information to the client; if the user selects to not receive the requested information, discarding the requested information. 10. The method of claim 7 further comprising the steps of: downloading a client version of a virus checker application to the web client; and causing the client version of the virus checker application to be executed on the web client to check for viruses on the web client. 11. The method of claim 7 further comprising the step of notifying at least one authority when a virus is detected. 12. The method of claim 7 further comprising the step of providing a user feedback mechanism that allows a user to input information regarding a virus. 13. A method for doing business, the method comprising the steps of: (A) providing a web server computer system comprising: a memory; a virus checker application residing in the memory; a web server application residing in the memory; a virus control mechanism residing in the memory; a network interface coupled via a network to a plurality of web clients; (B) prompting a user at one of the plurality of web clients to provide at least one virus checking preference; (C) when the web server application receives a request for information from a web client, the virus control mechanism performing the steps of: (C1) determining whether the request requires virus checking by examining the at least one virus checking preference that corresponds to the web client; (C2) if the request does not require virus checking, sending the requested information to the web client; (C3) if the request requires virus checking, invoking the virus checker application to check the requested information for a virus; (C4) if the requested information contains a virus, notifying the web client that the requested information contains a virus; (C5) if the requested information does not contain a virus, sending the requested information to the web client. 14. The method of claim 13 further comprising the step of charging a fee to the web client that varies according to the number of times the virus checker application is accessed. 15. The method of claim 13 further comprising the step of paying a fee to a provider of the virus checker application that varies according to the number of times the virus checker application is accessed. 16. The method of claim 13 wherein the web server computer system includes a plurality of virus checker applications residing in the memory, wherein the method further comprises the steps of: invoking one of the virus checker applications in step (C3); and paying a fee to each provider of the plurality of virus checker applications that varies according to the number of times each virus checker application is accessed. 17. The method of claim 13 further comprising the steps of: downloading a client version of the virus checker application to the web client; and causing the client version of the virus checker application to be executed on the web client to check for viruses on the web client. 18. The method of claim 13 further comprising the step of notifying at least one authority when a virus is detected. 19. The method of claim 13 further comprising the step of providing a user feedback mechanism that allows a user to input information regarding a virus.
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RELATED APPLICATION This patent application is a divisional of U.S. Ser. No. 09/605,258 entitled “WEB SERVER APPARATUS AND METHOD FOR VIRUS CHECKING” filed on Sep. 11, 2000, which is incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Technical Field This invention generally relates to web pages and more specifically relates to a web server apparatus and method that provides information to web clients. 2. Background Art Since the dawn of the computer age, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. The widespread proliferation of computers prompted the development of computer networks that allow computers to communicate with each other. With the introduction of the personal computer (PC), computing became accessible to large numbers of people. Networks for personal computers were developed that allow individual users to communicate with each other. One significant computer network that has recently become very popular is the Internet. The Internet grew out of this proliferation of computers and networks, and has evolved into a sophisticated worldwide network of computer system resources commonly known as the “world-wide-web”, or WWW. A user at an individual PC or workstation (referred to as a “web client”) that wishes to access the Internet typically does so using a software application known as a web browser. A web browser makes a connection via the Internet to other computers known as web servers, and receives information from the web servers that is rendered to the web client. One type of information transmitted from a web server to a web client is known as a “web page”, which is generally formatted using a specialized language called Hypertext Markup Language (HTML). Another type of information transmitted from a web server to a web client is e-mail messages and any files or other information attached to those messages. Yet another type of information transmitted from a web server to a web client is files that may be downloaded from a web site. Computer viruses have emerged as a very real threat to data in today's computer systems. Recently, the “I Love You” virus infected computer systems all over the world, and destroyed vast amounts of data, particularly image files. Virus checking application programs are currently available for checking viruses on individual computers. Norton Antivirus and McAfee VirusScan are two examples of commercially-available virus checkers. Known virus checkers run on a single computer system, such as a web server or a web client. These virus checkers typically are run at the user's request to determine whether there are any viruses on any specified drive or file. In addition, some virus checkers can be configured to automatically check incoming data in a downloaded file before allowing the file to be stored on the computer system. For example, Norton Antivirus allows a user to select an option that checks all downloaded files before passing them on to the user's computer system. However, all of the known virus checkers operate on one particular computer system, and there is currently no way for a virus checker on one system to check for viruses on a different computer system. With the growing popularity of the Internet, an ever-increasing number of web clients are connected to web servers. A web server acts as a conduit through which information is passed to numerous web clients. If a virus checker could be implemented on a web server to check all information flowing through it, the need for local virus checking at individual web client workstations would be greatly reduced. Without a way for a web server to check information flowing to web clients for viruses, the current methods for virus checking will continue to allow viruses to spread and cause considerable damage before they can be controlled. DISCLOSURE OF INVENTION According to the preferred embodiments, a web server computer system includes a virus checker and mechanisms for checking e-mails and their attachments, downloaded files, and web sites for possible viruses. When an e-mail message contains a detected virus, the message is discarded, and both the sender and recipient are informed via e-mail that the message contained a virus. When an e-mail attachment contains a detected virus, the attachment is deleted, and the e-mail message without the attachment is sent to the web client, along with a message explaining that the e-mail message had an attachment that was automatically deleted because it had a virus. When a downloaded file contains a virus, the downloaded file is deleted, and an error message is sent to the web client to inform the web client that the requested file had a virus. When a requested web site (i.e., Uniform Resource Locator (or URL)) has been labeled as a source for a known virus, a message is sent to the web client stating that a virus may have been downloaded from that URL. In addition, if the requested URL has not been labeled as a source for a known virus, but it contains links that have been so labeled, the web page is processed before being sent to the user to identify those potentially dangerous links. In this manner a web server can perform virus checking of different types of information real-time as the information is requested by a web client. In addition, a web client may also request that the server perform virus checking on a particular drive on the web client. In this case, the web server may receive information from the web client drive, scan the information for viruses, and inform the web client whether any viruses were found. In the alternative, the web server may download a client virus checker to the web client and cause the client virus checker to be run on the web client. The preferred embodiments thus allow a virus checker on a web server to dynamically scan incoming data, and to scan web clients coupled to the web server, thereby eliminating the need for virus checking software to be installed on each web client. The preferred embodiments also provide a virus information database that allows sharing information relating to viruses with other web servers and with appropriate authorities, such as law enforcement agencies. A user feedback feature also allows a client to inform the web server of information regarding a new virus. Another feature of the preferred embodiments is that senders of viruses are notified when the web server detects a virus, thus helping to inhibit the proliferation of the virus. The foregoing and other features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and: FIG. 1 is a block diagram of an apparatus in accordance with the preferred embodiments; FIG. 2 is a block diagram of a prior art apparatus for accessing information on a web server by one or more web clients; FIG. 3 is a block diagram of an apparatus in accordance with the preferred embodiments; FIG. 4 is a flow diagram of a method for a web server to scan requested information for a virus before serving that information to a web client in accordance with the preferred embodiments; FIG. 5 is a block diagram of the user list of FIGS. 1 and 3; FIG. 6 is a diagram of a display window for a user to define virus checking preferences for the web server in FIGS. 1 and 3; FIG. 7 is a flow diagram of a method performed by the e-mail virus processing mechanism 134 in FIGS. 1 and 3 in accordance with the preferred embodiments; FIG. 8 is a flow diagram of a method performed by the file virus processing mechanism 136 in FIGS. 1 and 3 in accordance with the preferred embodiments; FIG. 9 is a flow diagram of a method performed by the web page virus processing mechanism 132 in FIGS. 1 and 3 in accordance with the preferred embodiments; FIG. 10 is a flow diagram of a method for performing a virus check on a web client at the request of a user in accordance with the preferred embodiments; FIG. 11 is a diagram of a display window that may be displayed to a user to define a virus that is not recognized by the virus checker or the virus information database; and FIG. 12 is a flow diagram of a method for doing business in accordance with the preferred embodiments. BEST MODE FOR CARRYING OUT THE INVENTION Overview The method and apparatus of the present invention has particular applicability to a web client receiving information from a web server via the Internet. For those individuals who are not familiar with the Internet, a brief overview of relevant Internet concepts is presented here. An example of a typical Internet connection is shown by the apparatus 200 in FIG. 2. A user that wishes to access information on the Internet 170 typically has a computer workstation referred to as a “web client” (such as web client 210B) that executes an application program known as a web browser 230. A web client, represented by 210A, 210B, and 210C in FIGS. 2 and 3, is referred to herein as a web client 210. Under the control of web browser 230, web client workstation 210 sends a request for a web page over the Internet 170. Web page data can be in the form of text, graphics and other forms of information, collectively known as MIME data. Each web server on the Internet has a known address, termed the Uniform Resource Locator (URL), which the web browser uses to connect to the appropriate web server. Because web server 220 can contain more than one web page, the user will also specify in the address which particular web page he wants to view on web server 220. A web server computer system 220 executes a web server application 240, monitors requests, and services requests for which it has responsibility. When a request specifies web server 220, web server application 240 generally accesses a web page corresponding to the specific request, and transmits the web page via the Internet to the web browser 230 on the user's workstation 210. Known web browsers include Netscape Communicator and Microsoft Internet Explorer. A web page may contain various types of data, including MIME data. Most web pages include visual data that is intended to be displayed on the monitor of web client 210. Web pages are generally written in Hypertext Markup Language (HTML). When web server 220 receives a web page request, it will send the requested web page in HTML form across the Internet 170 to the requesting web browser 230. Web browser 230 understands HTML and interprets it and outputs the web page to the monitor (or display) of user workstation 210. This web page displayed on the user's screen may contain any suitable MIME data, including text, graphics, audio elements, video elements, and links (which reference addresses of other web pages). These other web pages (i.e., those represented by links) may be on the same or on different web servers. The user can invoke these other web pages by clicking on these links using a mouse or other pointing device. This entire system of web pages with links to other web pages on other servers across the world is known as the “World Wide Web”. In addition to web pages, web servers may also provide other types of information to a web client. For example, a web server 220 may execute an e-mail server application 250, which receives e-mails from its registered users and sends those e-mails on towards their ultimate destination. In addition, e-mail server application 250 receives e-mail messages for all of its registered users, and routes each message to the appropriate user. Another type of data that may be passed through a web server to a web client is a downloaded file. A file may be downloaded using many different methods. For example, a user may click on a link on a web page that causes a file to be loaded. Some files may be contained in or referenced by web pages, and may be automatically downloaded when a page that references it is downloaded. Of course, other suitable methods exist for downloading a file, and the preferred embodiments herein expressly extend to any and all methods for transferring any type of information between a web server and a web client. Detailed Description A web server apparatus and method in accordance with the preferred embodiments automatically screens information requested by a web client for viruses according to defined user virus checking preferences, and takes appropriate action when a virus is found or when there is a threat of a URL containing a virus or a reference to a virus. In addition, the preferred embodiments allow a user to perform virus scans on a web client drive, such as a disk drive or a CD-ROM drive, using the virus checker that resides on the web server. This configuration allows one virus checker on the web server to protect each web client connected to it from viruses without the need for virus checking software to be installed on each web client. Because one virus checker on the web server can service a large number of web clients, the process of updating the virus checker to recognize new viruses is greatly simplified compared to updating virus checkers on each web client. In addition, the likelihood of a web server spreading viruses is greatly reduced when information received by the web server is checked for viruses before forwarding the information to a web client. Referring to FIG. 1, one specific implementation of a web server computer system in accordance with the preferred embodiments is an AS/400 computer system 100. Computer system 100 comprises a processor 110 connected to a main memory 120, a mass storage interface 130, a display interface 140, and a network interface 150. These system components are interconnected through the use of a system bus 160. Mass storage interface 130 is used to connect mass storage devices (such as a direct access storage device 155) to computer system 100. One specific type of direct access storage device is a floppy disk drive, which may store data to and read data from a floppy diskette 195. Main memory 120 in accordance with the preferred embodiments contains data 121; an operating system 122; a web server application 123; an e-mail server application 124; a virus checker application 125 with associated virus definitions 126; a user list 127 with associated user virus checking preferences 128; a virus control mechanism 131 that includes a web page virus processing mechanism 132, an e-mail virus processing mechanism 134, and a file virus processing mechanism 136; and a virus information database 138. Computer system 100 utilizes well known virtual addressing mechanisms that allow the programs of computer system 100 to behave as if they only have access to a large, single storage entity instead of access to multiple, smaller storage entities such as main memory 120 and DASD device 155. Therefore, while the items 121-128 and 131-138 are shown to reside in main memory 120, those skilled in the art will recognize that these items are not necessarily all completely contained in main memory 120 at the same time. It should also be noted that the term “memory” is used herein to generically refer to the entire virtual memory of computer system 100. Data 121 represents any data that serves as input to or output from any program in computer system 100. Operating system 122 is a multitasking operating system known in the industry as OS/400; however, those skilled in the art will appreciate that the spirit and scope of the present invention is not limited to any one operating system. Web server application 123 is a computer program that monitors requests for information, and services requests for which it has responsibility. In other words, when a web client requests a web page that is stored on a hard disk drive (e.g., 155) on web server 100, the web server application 123 delivers the requested web page to the requesting web client. The e-mail server application 124 is a computer program that sends and receives e-mail messages and their attachments. When a web client that is a registered user of the e-mail server application 124 wants to send an e-mail message, the message is sent from the web browser to the web server that contains the e-mail server application 124, which then sends the message on towards its intended recipient. Virus checker application 125 is a computer program that detects the presence of viruses that are defined in its virus definitions 126. Note that virus definitions 126 may include specific viruses, as well as particular activity (such as writing to the boot record of a hard disk drive) that may signal a virus. Virus checker application 125 is similar to the known virus checkers that are commercially available today. Note, however, that virus checker application 125 must be able to run in a command mode rather than using a graphical user interface that requires user input, because the web server application 123, e-mail server application 124, and virus control mechanism 131 need to be able to initiate a virus scan using virus checker application 125 and receive results of the virus check without user intervention. The user list 127 is a list of users that are registered to use the virus control mechanism 131. The user list 127 includes a list of users, and their corresponding virus checking preferences 128 that determine how the web server application 123, e-mail server application 124, and/or virus control mechanism 131 screen incoming information for viruses. Virus control mechanism 131 includes the web page virus processing mechanism 132, e-mail virus processing mechanism 134, and file virus processing mechanism 136. Web page virus processing mechanism 132 checks a web client's request for a web page to determine whether the web page or any contained links were the source of a virus in the past. The virus information database 138 is a database of virus information that relates to web server computer system 100. Note that virus information database 138 may be a local database, or may be a large centralized database that includes the virus information for many web servers, such as a centralized database that could be accessed via a web site. Virus information database 138 may include a specification of known viruses, along with statistics for which ones have been encountered and when. In addition, virus information database 138 may include a list of web sites that are known to contain viruses, or from where viruses were downloaded. A web site that contains a virus or from which a virus was downloaded is referred to herein as a “bad” URL. Using the virus information database 138, web page virus processing mechanism 132 can warn a web client that has requested a web page at a bad URL, or that has requested a web page that includes links to a bad URL. E-mail virus processing mechanism 134 processes e-mails received by e-mail server application 124 from users in the user list 127 that are to be sent out to designated recipients, and processes e-mails received by e-mail server application 124 from other e-mail servers. E-mail virus processing mechanism 134 preferably scans both incoming and outgoing e-mail messages for viruses. If a virus is detected in the e-mail itself, the e-mail message is deleted, and an e-mail message is sent to the sender and intended recipient notifying both that the e-mail contained a virus. If a virus is detected in an attachment to an e-mail message, the attachment is deleted, and the message without the attachment is sent to the intended recipient, along with a message from the e-mail server application 124 that states that the attachment was deleted before delivery because it contained a virus. This message could be included by modifying the original e-mail message, or could be sent in a separate e-mail message. File virus processing mechanism 136 processes files that a web client has requested to download to determine if a requested file has a virus. If the downloaded file contains a virus, the file is deleted, and the requesting web client is notified that the download could not be completed because the file contained a virus. If the downloaded file has no virus, it is passed on to the requesting web client. Note that in the discussion above, the deletion of an e-mail message, attachment, or file is with respect to the intended recipient, but the e-mail message, attachment or file could be stored for analysis or for communication to the appropriate authorities. Each of the web page virus processing mechanism 132, the e-mail virus processing mechanism 134, and the file virus processing mechanism 136 preferably operate according to the user virus checking preferences 128. If the user so desires, any or all of these mechanisms may automatically check for viruses without user intervention, making these virus checks nearly transparent to the user. If no viruses are detected, the only indication to the user of the automatic virus checking that is occurring may be a slightly longer time to receive the requested information. Of course, if a virus is detected, the user will be provided with notification of the virus and may be presented with options for dealing with the virus. Processor 110 may be constructed from one or more microprocessors and/or integrated circuits. Processor 110 executes program instructions stored in main memory 120. Main memory 120 stores programs and data that processor 110 may access. When computer system 100 starts up, processor 110 initially executes the program instructions that make up operating system 122. Operating system 122 is a sophisticated program that manages the resources of computer system 100. Some of these resources are processor 110, main memory 120, mass storage interface 130, display interface 140, network interface 150, and system bus 160. Although computer system 100 is shown to contain only a single processor and a single system bus, those skilled in the art will appreciate that the present invention may be practiced using a computer system that has multiple processors and/or multiple buses. In addition, the interfaces that are used in the preferred embodiment each include separate, fully programmed microprocessors that are used to off-load compute-intensive processing from processor 110. However, those skilled in the art will appreciate that the present invention applies equally to computer systems that simply use I/O adapters to perform similar functions. Display interface 140 is used to directly connect one or more displays 165 to computer system 100. Display 165 may be a simple display device, such as a monitor, or may be a fully programmable workstation, and is used to allow system administrators and users to communicate with computer system 100. Network interface 150 allows computer system 100 to send and receive data to and from any network the computer system may be connected to. This network may be a local area network (LAN), a wide area network (WAN), or more specifically the Internet 170 (as shown in FIG. 3). Suitable methods of connecting to the Internet include known analog and/or digital techniques, as well as networking mechanisms that are developed in the future. Many different network protocols can be used to implement a network. These protocols are specialized computer programs that allow computers to communicate across a network. TCP/IP (Transmission Control Protocol/Internet Protocol), used to communicate across the Internet, is an example of a suitable network protocol. At this point, it is important to note that while the present invention has been and will continue to be described in the context of a fully functional computer system, those skilled in the art will appreciate that the present invention is capable of being distributed as a program product in a variety of forms, and that the present invention applies equally regardless of the particular type of signal bearing media used to actually carry out the distribution. Examples of suitable signal bearing media include: recordable type media such as floppy disks (e.g., 195 of FIG. 1) and CD ROM, and transmission type media such as digital and analog communications links. FIG. 1 illustrates that mechanisms 132, 134 and 136 may all reside in a virus control mechanism 131 that is separate from web server application 123 and e-mail server application 124. In the alternative, these mechanisms could be separated and incorporated within the web server application and e-mail application. One such implementation is shown in web server 300 in FIG. 3, which shows that the web page virus processing mechanism 132 and file virus processing mechanism 136 may reside within a web server application 340 in accordance with the preferred embodiments, and that the e-mail virus processing mechanism 134 may reside within the e-mail server application 350 in accordance with the preferred embodiments. This configuration allows implementing the functions of these mechanisms 132, 134 and 136 within the web server application 340 and the e-mail server application 350, rather than providing a separate, dedicated software application 131 as shown in FIG. 1. Referring now to FIG. 4, a method 400 in accordance with the preferred embodiments allows a virus checker on a web server to automatically check e-mail messages, web pages, and downloaded files for viruses before passing these on to a web client. Method 400 begins when a web client requests information that normally would flow through the web server to the web client (step 410). If the request does not require virus checking (step 420=NO), the requested information is sent to the web client (step 480). If the request requires virus checking (step 420=YES), a virus check is performed on the requested information (step 430). If no virus is found (step 440=NO), the requested information is sent to the web client (step 480). If a virus is found (step 440=YES), the web client is notified of the virus (step 450), and an entry is made in the virus information database (step 460) regarding the name of the virus, type, when detected, etc. Finally, the appropriate authorities may be notified of the virus (step 470). The term “appropriate authorities” is a broad term that encompasses anyone who may need to know about the occurrence of a virus, including a network administrator of a local area network, a web site administrator, a contact person in a virus detection company, and appropriate law enforcement officials, such as local, state, federal, and international law enforcement agencies. Step 420 in FIG. 4 determines whether a request requires virus checking. One suitable way to perform step 420 in accordance with the preferred embodiments is to provide a user list that specifies virus checking preferences for each user. One specific implementation of a user list 127 is shown in FIG. 5, and includes a user name and corresponding virus checking preferences 128 that are preferably set by the individual users, but could also be set according to system defaults or overrides. FIG. 5 shows that a hypothetical user that has the user name of george123 has virus checking preferences that specify that all e-mails should be automatically checked for viruses, that all downloaded files should be automatically checked for viruses, that web sites may be checked upon explicit request of the user, and that Norton Antivirus is the virus checker to be used. Another hypothetical user has the user name of fred246, who has virus checking preferences 128 that specify that all e-mail should be automatically checked for viruses, that all downloaded files may be checked upon explicit request of the user, that virus checking on the user's web client may be performed upon explicit request of the user, and that Norton Antivirus is the virus checker to be used. The virus checking preferences 128 for a particular user may be setup by the web server sending a web page or other message to the user via the web client. One suitable example of a sample web page for setting up user virus checking preferences is shown as a display window 600 in FIG. 6. The user may click on radio buttons to determine whether e-mail, downloaded files, and web pages are never checked, checked by explicit request of the user, or always checked automatically for viruses before the web server delivers these items to the user via the web client. In addition, the user may sign up for e-mail notification that includes information on the latest viruses and reminders and strategies for virus protection and detection. A drop-down box 610 is provided to allow the user to specify which virus checker is used to perform the virus checks. FIG. 6 shows that the user has selected Norton Antivirus as the desired virus checking program. Note that the drop-down box may contain many different selections, including the names of many different virus checker applications, a “default” selection, and a selection that tells the web server to determine which virus checker is best for the particular type of information being checked. In addition, display window 600 allows the user to perform local virus checking on the web client computer system using a special client version of the selected virus checking program. When the user has entered the desired preferences in the display window 600, the user clicks on the OK button 620, which causes the user virus checking preferences to be stored in the user list 127. If the user decides to not specify virus checking preferences, the user clicks on the cancel button 630, which cancels the setting up of user virus checking preferences. The specific selections in the display window 600 of FIG. 6 correspond to the virus checking preferences 128 for the user with the user name of george123 in FIG. 5. Referring back to FIGS. 1 and 3, each of mechanisms 132, 134 and 136 perform different functions. One suitable method in accordance with the preferred embodiments for the e-mail processing mechanism 134 is illustrated as method 700 in FIG. 7. Method 700 begins when an e-mail message is received that is intended for one of the users in the user list 127 (step 710). If the virus checking of e-mail messages is not enabled in the user virus checking preferences 128 for the user that is the intended recipient of the e-mail message (step 712=NO), the e-mail is sent to the recipient (step 714). On the other hand, if virus checking of e-mail messages is enabled in the user virus checking preferences 128 for the intended recipient (step 712=YES), the e-mail virus processing mechanism reads the e-mail message (step 720), and checks the e-mail message body for viruses (step 722) using the selected virus checker application. Note that the term “e-mail message body” includes all parts of the e-mail other than attachments, including the fields for sender and recipient, subject line, main portion of message, etc. If no viruses are found (step 724=NO), and there are no attachments to the e-mail message (step 740=NO), the e-mail message is sent to the recipient (step 714). If a virus is found (step 724=YES), the e-mail message is deleted (step 730), and a separate e-mail is sent to the intended recipient of the e-mail informing the recipient that the deleted e-mail message contained a virus and was automatically deleted (step 732). In addition, any other information regarding the virus-infected e-mail message could be sent to the intended recipient in step 732 as well. Next, method 700 e-mails the sender of the e-mail message that included the virus to inform the sender that they sent a virus (step 734). This step is particularly significant because it prevents a user from repeatedly and unknowingly sending out a virus as part of an e-mail message. Next, information regarding the virus is entered into the virus information database (step 736). If this is the first time this web server has detected this particular virus, step 736 preferably makes a new entry in virus information database 138 with pertinent information regarding the virus. If the web server has seen this particular virus before, step 736 preferably updates an existing entry in virus information database 138. Note that the information in virus information database 138 may include any pertinent information regarding the virus including, without limitation, its size in bytes, where the virus came from, when the virus was detected, the location of each detection, etc. Next, method 700 notifies the appropriate authorities regarding the virus (step 738). As stated above, the authorities notified can include any human being or computer that has a need to know about computer viruses. If no virus was found in the e-mail message body (step 724=NO), but there is one or more attachments to the message (step 740=YES), all attachments are checked for viruses (step 742). If no virus is found (step 744=NO), the e-mail message and any attachments are sent to the recipient (step 714). If a virus is found (step 744=YES), the infected attachment or attachments are deleted (step 750), and the e-mail message without the infected attachment or attachments are sent to the intended recipient (step 752). At this point method 700 e-mails the recipient regarding the deleted attachment (step 732), e-mails the sender a warning that a virus was detected in the e-mail message (step 734), enters appropriate information into the virus information database (step 736), and notifies the appropriate authorities of the virus (step 738). Method 700 thus succeeds in automatically detecting viruses in an e-mail message and its attachments when the user's virus checking preferences specify that e-mails are to be checked for viruses. If the virus checking preferences specify that e-mail messages are always verified for viruses, the answer to step 712 for that user is always YES, and the e-mail message and any attachments will automatically be checked each time an e-mail message is received. In the alternative, if the virus checking preferences specify that e-mail message may be verified upon request of the user, the answer to 712 is NO unless the user has explicitly asked to check a particular e-mail message for viruses, at which time the answer to step 712 becomes YES due to the user enabling the virus check by explicitly requesting that the check be performed. While method 700 applies to e-mail messages received by e-mail server application 124 that specify a registered user as the recipient (i.e., for incoming mail), the preferred embodiments also extend to virus checking of e-mail messages and their attachments that are sent by registered users to others (i.e., in outgoing mail). One suitable method in accordance with the preferred embodiments for the file virus processing mechanism 136 in FIGS. 1 and 3 is illustrated as method 800 in FIG. 8. Method 800 begins when a client requests to download a file (step 810). The file can be any suitable file, such as an application, a text file, an audio file, a video file, or any other file that is capable of being downloaded. The file is first downloaded to the web server (step 812), and method 800 then determines whether the virus checking of downloaded files is enabled (step 814). If not (step 814=NO), the downloaded file is sent to the web client (step 816). If virus checking for downloaded files is enabled (step 814=YES), the file that was downloaded in step 812 is checked for viruses (step 820). If no virus was found during the virus check (step 822=NO), the downloaded file is sent to the web client (step 816). If a virus is found in the downloaded file (step 822=YES), the file is deleted (step 830), and a status message is sent to the web client showing the information on the file and its contained virus that was deleted (step 832). Information about the file and its virus is then entered into the virus information database (step 834), and appropriate authorities are then notified of the virus (step 836). One suitable method in accordance with the preferred embodiments for the web page virus processing mechanism 132 in FIGS. 1 and 3 is illustrated as method 900 in FIG. 9. Method 900 begins when a web client requests a web page (step 910). The requested web page is then downloaded (step 912) to the web server. If the checking of viruses in web pages is not enabled (step 914=NO), the web page is sent to the client (step 916). If, however, the checking of web pages for viruses is enabled (step 914=YES), the uniform resource locator (URL) for the web page and for all links on the web page are compared to a list of known URLs in the virus information database 138 that were previously sources for viruses (step 920). If the URL of the web page itself is listed as bad (step 922=YES), a warning message is sent to the web client (step 930), which preferably informs the user that the requested web page may be the location of a virus, and asks if the user wants to continue to download the page anyway. If the user selects to download the page anyway (step 932=YES), the web page is sent to the client (step 916). If the user selects to not download the page (step 932=NO), the downloaded web page is deleted (step 940) and a message is provided to the web client stating that the loading of the web page was aborted (step 942). If the web page URL is not bad (step 922), method 900 next checks to see if the web page contains links to any bad URLs (step 950). If not (step 950=NO), the web page is sent to the web client (step 916). If the web page contains one or more links to bad URLs (step 950=YES), the downloaded web page is processed to identify the bad links (step 952), and the processed web page is sent to the web client (step 954). One suitable example would highlight the bad links in a particular color, or provide a text bubble message that warns the user that the link may be or have been the source of a virus. Referring now to FIG. 10, a method 1000 in accordance with the preferred embodiments allows a web server to download a special client copy of a virus checker program for execution on the web client to check for local viruses. Method 1000 begins when a user requests a virus check on the user's web client workstation (step 1010). In response, the web server downloads a client virus checker to the web client (step 1012). The web server then causes the web client to execute the client virus checker (step 1014). The client virus checker then reports the existence of any viruses to the server (step 1016). If no virus was found (step 1018=NO), a message reporting no viruses is sent from the web server to the web client (step 1020). If a virus was found (step 1018=YES), a message reporting the virus is sent to the client (step 1030), the virus information is entered into the virus information database (step 1040), and the appropriate authorities are notified of the virus (step 1050). Method 1000 thus allows a user to perform local virus checks using software downloaded from the web server, thereby eliminating the need for virus checking software to be installed on each web client, and offloading at the web server the burden of performing virus checking on the web clients. Another aspect of the present invention is the ability to inform the web server of a virus that the user may encounter, from either an external source, such as a disk drive or a CD-ROM drive, or a virus that was not detected by the web server. In this case the user may enter information regarding a virus into a virus feedback form. Display window 1100 in FIG. 11 shows a display that may be presented to a user to input information regarding a virus. Display window 1100 prompts the user to indicate the source of the virus. The user may cancel the virus feedback operation by clicking on the cancel button 1120. For the example in FIG. 11, we assume the user discovered a virus in a downloaded file, and wants to inform the web server of the URL that was used to download the virus. The user thus clicks on the “Downloaded File” radio button, and clicks on the continue button 1110. At this point another display window appears, prompting the user for other information relating to the virus. In this particular example, the next display screen would preferably allow the user to enter the URL from which the file with the virus was downloaded. If the e-mail radio button in display window 1100 were selected when the continue button 1110 is clicked, one or more display windows would then follow that allow the user to enter the sender of the e-mail, and whether the virus was in the subject line, message body, attachment, etc. In short, each selection in display window 1100 will cause another display window to be displayed with the continue button 1110 is clicked. The preferred embodiments extend to any mechanism for a user to provide feedback about a virus to the web server. The preferred embodiments also include a method for doing business. Referring to FIG. 12, a method 1200 for doing business begins by providing a web server computer system, such as computer system 100 in FIG. 1 and 300 in FIG. 3. Next, a user is prompted for virus checking preferences (step 1220), which allow the user to setup any suitable preferences for virus checking of information that flows through the web server, as well as information on the user's web client. The next step is to process any request for information according to the user's virus checking preferences, invoking the virus checker and notifying the web client as required (step 300). Note that step 300 in FIG. 12 represents method 300 in FIG. 3. Steps 1210, 1220 and 300 are the core steps to the method for doing business in accordance with the preferred embodiments. The virus checking service may be included in a flat monthly rate charged to a user by an internet service provider (ISP) that provides the web server. The virus checking capability may be offered as part of the regular monthly fee to distinguish the ISP's service from the competition. In the alternative, the virus checking may be charged to the user based on the number of times the virus checker application on the server was invoked on behalf of the user (step 1230). In addition, the provider of the virus checker application on the web server may be paid according to the number of times the virus checker was invoked (step 1240). Neither of steps 1230 nor 1240 are critical to the method of doing business in FIG. 12, but may be included if desired. Of course, other business models are possible as well, such as charging the user according to the number to times the virus checker actually detects and stops a virus, or paying the provider of the virus checker application based on the number of times a virus is detected. The preferred embodiments expressly extend to any and all methods for charging the user (or not) for the virus checking on the web server, and for paying the provider of the virus checker software for the use of the virus checker on the web server. One of the significant features of the preferred embodiments is the presence of a virus information database 138, as shown in FIGS. 1 and 3. Note that the virus information database 138 is different than the virus definitions 126 used by the virus checker application 125. Virus information database 138 is a repository of information concerning detected viruses, including the number of times the virus was detected, the time of detection, the origin of the virus, etc. Having this information available to the web server computer system allows the web server to log virus-related information and perform analysis on that information as needed. For example, when a virus in an e-mail is detected, the sender of the e-mail may be recorded in the virus information database 138. If the user sends a virus a second time, the user may be labeled in the virus information database as a user that has a history of sending viruses. This could result in the sender being notified that the web server is not accepting e-mails from the sender for a period of time due to excessive e-mails with viruses. The sender can thus be “branded” as a source of viruses, allowing the web server computer system to take any suitable action based on that knowledge. In another example, if a virus is detected in an e-mail message or its attachment, the e-mail virus processing mechanism could not only delete the infected message or attachment, but could delete other messages from the same sender that are similar (e.g., in size or attachment name) to the deleted message or attachment without explicitly performing virus checks on these similar messages. One skilled in the art will appreciate that many variations are possible within the scope of the present invention. Thus, while the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that these and other changes in form and details may be made therein without departing from the spirit and scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Technical Field This invention generally relates to web pages and more specifically relates to a web server apparatus and method that provides information to web clients. 2. Background Art Since the dawn of the computer age, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. The widespread proliferation of computers prompted the development of computer networks that allow computers to communicate with each other. With the introduction of the personal computer (PC), computing became accessible to large numbers of people. Networks for personal computers were developed that allow individual users to communicate with each other. One significant computer network that has recently become very popular is the Internet. The Internet grew out of this proliferation of computers and networks, and has evolved into a sophisticated worldwide network of computer system resources commonly known as the “world-wide-web”, or WWW. A user at an individual PC or workstation (referred to as a “web client”) that wishes to access the Internet typically does so using a software application known as a web browser. A web browser makes a connection via the Internet to other computers known as web servers, and receives information from the web servers that is rendered to the web client. One type of information transmitted from a web server to a web client is known as a “web page”, which is generally formatted using a specialized language called Hypertext Markup Language (HTML). Another type of information transmitted from a web server to a web client is e-mail messages and any files or other information attached to those messages. Yet another type of information transmitted from a web server to a web client is files that may be downloaded from a web site. Computer viruses have emerged as a very real threat to data in today's computer systems. Recently, the “I Love You” virus infected computer systems all over the world, and destroyed vast amounts of data, particularly image files. Virus checking application programs are currently available for checking viruses on individual computers. Norton Antivirus and McAfee VirusScan are two examples of commercially-available virus checkers. Known virus checkers run on a single computer system, such as a web server or a web client. These virus checkers typically are run at the user's request to determine whether there are any viruses on any specified drive or file. In addition, some virus checkers can be configured to automatically check incoming data in a downloaded file before allowing the file to be stored on the computer system. For example, Norton Antivirus allows a user to select an option that checks all downloaded files before passing them on to the user's computer system. However, all of the known virus checkers operate on one particular computer system, and there is currently no way for a virus checker on one system to check for viruses on a different computer system. With the growing popularity of the Internet, an ever-increasing number of web clients are connected to web servers. A web server acts as a conduit through which information is passed to numerous web clients. If a virus checker could be implemented on a web server to check all information flowing through it, the need for local virus checking at individual web client workstations would be greatly reduced. Without a way for a web server to check information flowing to web clients for viruses, the current methods for virus checking will continue to allow viruses to spread and cause considerable damage before they can be controlled.
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<SOH> BRIEF DESCRIPTION OF DRAWINGS <EOH>The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and: FIG. 1 is a block diagram of an apparatus in accordance with the preferred embodiments; FIG. 2 is a block diagram of a prior art apparatus for accessing information on a web server by one or more web clients; FIG. 3 is a block diagram of an apparatus in accordance with the preferred embodiments; FIG. 4 is a flow diagram of a method for a web server to scan requested information for a virus before serving that information to a web client in accordance with the preferred embodiments; FIG. 5 is a block diagram of the user list of FIGS. 1 and 3 ; FIG. 6 is a diagram of a display window for a user to define virus checking preferences for the web server in FIGS. 1 and 3 ; FIG. 7 is a flow diagram of a method performed by the e-mail virus processing mechanism 134 in FIGS. 1 and 3 in accordance with the preferred embodiments; FIG. 8 is a flow diagram of a method performed by the file virus processing mechanism 136 in FIGS. 1 and 3 in accordance with the preferred embodiments; FIG. 9 is a flow diagram of a method performed by the web page virus processing mechanism 132 in FIGS. 1 and 3 in accordance with the preferred embodiments; FIG. 10 is a flow diagram of a method for performing a virus check on a web client at the request of a user in accordance with the preferred embodiments; FIG. 11 is a diagram of a display window that may be displayed to a user to define a virus that is not recognized by the virus checker or the virus information database; and FIG. 12 is a flow diagram of a method for doing business in accordance with the preferred embodiments. detailed-description description="Detailed Description" end="lead"?
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20040701
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20070213
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20050106
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58374.0
| 0
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DONAGHUE, LARRY D
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WEB SERVER APPARATUS AND METHOD FOR VIRUS CHECKING
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
| 2,004
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10,883,156
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ACCEPTED
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Single-use long-life faucet-mounted water filtration devices
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Single-use long-life faucet mounted water filtration devices are disclosed. A bathroom water filtration device having two outlets for filtered water is disclosed. Additionally, a fountain head is included for use in the bathroom water filtration device. The water filtration device is of unibody construction formed by ultrasonically welding certain parts thereof together. Since the devices disclosed are disposable, no filter replacement or other maintenance is performed. A gate, magnet(s), sensor and electronics provide an indication of filter performance enabling disposal of the water filtration device and installation of a new device. A kitchen water filtration device is larger than the bathroom device. Both the kitchen and bathroom water filtration devices are small and are mounted behind the faucet connection so as to facilitate full utilization of the sink or wash basin.
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1. A water filtration device comprising: a water filter housing having an inlet and an outlet; said water filter housing includes an end cap; a filter end cap; a wet chamber formed within said water filter housing and said filter end cap; a water filter non-removably contained within said water filter housing; a passageway communicating between said wet chamber and said water filter; a gate having a first magnet affixed thereto resides in said chamber; said filter end cap includes a second magnet affixed thereto; said gate swinging between a first position and a second position; a gate position sensor resides in said end cap of said water filter housing; said gate position sensor being actuated when said gate swings to said second position and said magnet is in proximity to said sensor; and, said first and second magnets being coupled each to the other when said gate is in said first position. 2. A water filtration device as claimed in claim 1 wherein said gate is pivotably connected to said filter end cap. 3. A water filtration device as claimed in claim 1 wherein said gate includes a generally conically shaped protrusion and said filter end cap includes a cylindrical passageway extending therefrom. 4. A water filtration device as claimed in claim 3 wherein said generally conically shaped protrusion resides partially within said cylindrical passageway extending from said filter end cap when no water is flowing through said water filtration device. 5. A water filtration device as claimed in claim 4 wherein said generally conically shaped protrusion exits said cylindrical passageway extending from said filter end cap when water is flowing through said water filtration device. 6. A water filtration device as claimed in claim 5 further comprising electronics and a light emitting diode; said electronics output a signal to said light emitting diode which indicates the performance of the water filtration device. 7. A water filtration device as claimed in claim 1 wherein said water filter is affixed to said water filter end cap and a second water filter end cap; and, said water filter end cap includes a first hinge member and said gate includes a second hinge member which coacts with said first hinge member to enable'said gate to swing between said first and second positions. 8. A single-use water filtration device as claimed in claim 7 further comprising a gate pivotally mounted to one of said filter end caps; said gate includes a magnetic portion; a sensor, electronics associated therewith and a filter performance indicator mounted in said open end of said filter housing end cap; a filter housing end plate affixed to said filter housing end cap; said gate swinging from a first position to a second position actuating said sensor; and, said electronics outputting a signal to an indicator of the performance of the filter. 9. A filter performance indicator comprising: a gate; said gate rotatable between first and second positions; a first magnet; said first magnet affixed to said gate; a switch; said first magnet opening and closing said switch; and, an electric circuit for measuring the time when said switch is closed. 10. A filter performance indicator as claimed in claim 9 further comprising a filter end cap; said filter end cap includes a second magnet affixed thereto; said first magnet and said second magnet coacting together and ensuring that said gate resides in said first position when said filter is not filtering. 11. A filter performance indicator as claimed in claim 10 wherein said electric circuit is an integrated circuit. 12. A filter performance indicator as claimed in claim 10 wherein said switch is a reed switch. 13. A filter performance indicator as claimed in claim 10 wherein said electric circuit has three discrete outputs. 14. A filter performance indicator for use in a water filter, comprising: a gate having a first magnet affixed thereto; a filter boundary having hinges thereon forming a pivot thereon and a second magnet affixed thereto; said gate being pivotally affixed to said hinges; said gate movable in an arc between a first position when no flow impinges upon said gate and said first and second magnets are coupled together and a second position when flow does impinge upon said gate and said first and second magnets are not coupled together; and, a filter housing having a sensor therein for sensing the presence of said gate and said first magnet when said gate is in said second position. 15. A filter performance indicator for use in a water filter as claimed in claim 14 wherein said gate includes a conical protrusion extending therefrom and said filter boundary includes a cylindrical passageway extending therefrom. 16. A filter performance indicator for use in a water filter as claimed in claim 15 wherein when said water flow impinges upon said conical protrusion of said gate decoupling said first magnet from said second magnet, and wherein when no water flow impinges upon said conical protrusion of said gate said first and second magnets are coupled together and said first magnet is not in proximity to said second magnet.
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This patent application is a continuation in part of copending U.S. patent application Ser. No. 10/613,950 filed Jul. 3, 2003 and claims priority thereto. FIELD OF INVENTION The field of the invention is water filtration devices. BACKGROUND OF THE INVENTION The demand for pure water continues to grow rapidly due to increasing concerns about the quality and safety of tap water, the popularity of water as a beverage (instead of soda and alcohol) and the growing awareness that most people do not drink enough water as prescribed by the medical community. Water is supplied from municipal water systems (many of which are aging), private water systems and wells in the United States. Frequently, this water has poor taste, particulates, unwanted odors and in many cases contaminants contained in it. Municipal water is commonly treated with chlorine to eliminate bacterial contaminants. Chlorine adds what most people feel is an unpleasant taste and odor. Water conditions vary greatly according to the geographic area and therefore travelers may also experience these problems as they visit hotel and motel rooms around the country. It is desirous to remove bad tastes, odors, sediment and contaminants before ingesting the water or using it for cooking food. Water treatment devices of many varieties have proven effective in accomplishing water purification. Generally these devices work through chemical and mechanical actions that remove contaminants and impurities from water. These filters have a finite life. Sediment can eventually clog a filter and chemical reactions realized through adsorption (carbon media) and ion exchange (cation resin) have a limited capacity. U.S. Pat. No. 5,989,425 to Yonezawa et al. discloses a multi-way valve and water purifier. The multi-way valve is disclosed as a small-sized one which may be used with a small-sized water purifier. The device disclosed in the '425 patent is a faucet mounted filter and it is designed for removing and exchanging valve bodies. U.S. Pat. No. 5,017,286 to Heiligman and U.S. Pat. No. Re. 35667 to Heiligman disclose a vertical filter enclosed in a housing and the housing is supported by a duct. The vertical filter may be permanently secured to the filter by hot melt adhesive which renders the filter non-removable. Further, the vertical filter may be pre-wrapped with a porous paper pre-filter. The device disclosed in the '286 patent is a faucet mounted filter. If the filter is glued to the filter housing the filter housing must be removed and discarded together with the filter. A new filter housing (and filter) must then be mounted onto the duct of the diverter valve each time the filter housing is replaced. This involves time consuming labor in the case of each embodiment disclosed in the '286 patent. In one embodiment of the '286 patent, the filter housing is secured by a retaining clip. In another embodiment disclosed in the '286 patent, the male duct of the filter housing is press-fit into an opening in the diverter valve. Alternatively, the male duct of the filter housing may be affixed to the diverter valve by a U-clip, cotter pin or the like. The filter housing as disclosed in the '286 patent is disclosed as residing vertically in front of the faucet. In short, it is not a simple matter to change the filter housing of the device disclosed in the '286 patent. U.S. Pat. No. 5,527,451 to Hembree et al. discloses a faucet mounted filter utilizing a replacement filter cartridge. The replacement filter cartridge resides within a larger rotatable housing which channels water flow either into the filter or through the diverter valve assembly. Hembree et al. also discloses a very complicated flow totalization mechanism which includes porting water to a turbine driven mechanism prior to filtering thereof. U.S. Pat. No. 6,571,960 B2 to Williamson et al. discloses a faucet-mounted water filtration device whose filter housing includes a valve therein and whose filter housing extends longitudinally rearwardly from the point of attachment to the faucet. The filters in Williamson et al. are replaceable filter cartridges. U.S. Pat. No. 6,284,129 B1 to Giordano et al. discloses a rotating a magnetized impeller actuating a reed switch. In each of the foregoing disclosures, the devices disclosed therein are designed for disassembly of some sort as a matter of maintenance of the filtration device. This requires labor and attendant time. Complex flow totalization mechanisms such as the one disclosed in Hembree et al. '451 present maintenance problems. The need to change the filter and/or the filter housing and/or the diverter valve all require labor and attendant time. In each of the foregoing disclosures, the devices disclosed therein are designed for disassembly of some sort as a matter of maintenance of the filtration device. Filtration devices customarily employ replaceable filter cartridges of some type. These arrangements require either a coupling arrangement for attaching and detaching a replacement filter cartridge or a large chamber to entirely enclose the replacement filter cartridge. Both approaches require additional components and materials that add to the manufactured cost and complexity of the device. Furthermore, each of the foregoing disclosures, by requiring the replacement of the filter element, cause great inconvenience to the user by having him search for and procure replacement filter elements at considerable cost. This arrangement, while lucrative for the manufacturer, is a well documented nuisance for the consumer. In addition, most of the devices in the related art, owing to their need for easy access and maintenance are relatively large and obtrusive partially blocking the sink basin. Finally, the devices noted above and most others despite the availability of high capacity filter media are not designed for long life so as to maximize the frequency with which users must purchase replacement filter elements. It is therefore desirable to have a small faucet-mounted water filtration device which is a single-use, long-life water filtration device which includes an indicator of filter performance. By single use it is meant that it is discarded when its performance indicator reveals that the efficacy of the filter has been diminished. It is also desirable to have the filter housing of the water filtration device mounted behind the connection to the faucet to enable full access to the sink basin beneath the faucet. SUMMARY OF THE INVENTION A single-use faucet-mounted water filtration device is provided. The device is of uni-body construction and has no removable or replaceable parts yet provides long life operation. This arrangement makes the device more convenient to use compared with other devices that require frequent replacement of filter cartridges. The device is constructed with a minimum of components making it relatively small in size and less costly to manufacture. While compact, the device is able to hold enough filter media to allow for long life operation. The life of the water filtration device is dependent upon the type of filter media used, sizing and geometry of the filter media, and the sizing and geometry of water flow paths. For instance, water filtration devices having a useful life of 300 gallons or more can be made utilizing the teachings of the instant invention. Water filtration devices having useful lives smaller than 300 gallons may also be made utilizing the teachings of the instant invention. Performance indications as a function of integrated flow are indicated by a light emitting diode. The main housing of the devices resides beneath the faucet neck and rearward of the water discharge point thus not obstructing the sink basin. A single-use device is provided for use in a kitchen sink and a device is provided for use in a bathroom sink. Unlike devices in the related art the bathroom embodiment of the single-use faucet filter is scaled to the small size of bathroom sinks and therefore practical for use in bathrooms. The bathroom filter device allows residential users to have the benefit of filtered water in close proximity to the bedroom avoiding the inconvenience of going to a kitchen sink for water during the night. In addition, because the bathroom device is small and disposable it may be taken with a traveler and installed in a hotel or motel room. Further, as travelers readily discern the differences between water and its tastes from one place to another it is highly desirable that the water filter be portable. The invention includes a front housing connectable to a water faucet and a filter housing having an inlet and an outlet. An end cap of the filter housing completes the filter housing. The front housing is non-removably affixed to the filter housing and the water filter is non-removably contained within the water filter housing. The water filter housing includes a chamber in communication with the water filter. The filter is preferably activated carbon and includes a filter pre-wrap. Other filter media may be used. The outlet resides in the chamber. Alternatively, a second outlet may also reside in the chamber in the embodiment of the bathroom filter. The single use water filtration device is small. The embodiment designed for bathroom use has a filter diameter less than or equal to 1.6 inches. The embodiment designed for kitchen use has a filter diameter less than or equal to 2.2 inches. The water filtration devices disclosed herein, namely the bathroom and kitchen embodiments, reside substantially rearwardly with respect to the water faucet. Other diameters and sizes of the water filtration devices disclosed herein may be made using the teachings hereof. The filter includes ends thereof each secured to an end cap. The end caps have peripheral seal portions which seal against the interior of the filter housing. A housing end cap is ultrasonically welded to the filter housing. Other welding methods such as microwave, radio frequency (RF), heat and induction welding may be employed to weld various portions of the water filtration devices disclosed herein together. The second outlet includes a valve seat and a valve interposed in the filter housing being operable against the valve seat of the second outlet for controlling the flow out of the second outlet. The valve includes a plunger having a foot and an elastomeric ball valve or boot residing over the foot. The foot of the plunger and the elastomeric ball valve reside within the housing. A handle is pivotally connected to the end cap of the filter housing and engages the plunger such that when the plunger is depressed the elastomeric ball valve moves inwardly toward the center of the housing and away from the seat of the second outlet. A fountain head is rotatably secured in the plunger and lever for communication with a passageway in the plunger. A spring is interposed between the plunger and the filter housing urging the elastomeric ball valve against the valve seat of the second outlet. A front housing having first and second passageways is non-removably affixed to the filter housing. The front housing includes a directional valve residing within the front housing and movable therein for directing water into the filter for filtering or through the front housing for direct use of the unfiltered water. The filter housing includes three protrusions which interengage corresponding apertures in the front housing. The front housing also includes a continuous periphery welded to the filter housing by one of the aforementioned methods. The filter housing includes a recess whose shape is the reciprocal of the continuous periphery of the front housing and the continuous periphery of the front housing fits snugly within the recess in the filter housing. The end cap of the filter housing is welded to the filter housing. Three parts or pieces, the filter housing, the front housing and the end cap of the filter housing are welded together to provide a unibody or integral construction. A gate having a magnet affixed therein resides in the chamber and swings between a first position and a second position. Spacers extending from the end cap serve to ensure that the gate remains in alignment with respect to the earth. These spacers also serve to ensure that the filter subassembly remains in proper position. The first end cap of the filter includes a first hinge member and the gate includes a second hinge member which coacts with the first hinge member to enable the gate to swing between first and second positions. A gate position sensor resides in a dry portion of the end cap of the water filter housing and is actuated when the gate swings to the second position and the magnet is in proximity to the sensor. An electronic package and a light emitting diode reside in the dry portion of the end cap of the water filter housing. The electronic package outputs a signal to the light emitting diode which indicates the performance of the water filtration device. The electronic package outputs three discrete signals to the light emitting diode to indicate three performance levels of the filter. A filter performance indicator for use in a water filter which includes a gate having a first magnet affixed thereto and a filter boundary having hinges thereon forming a pivot thereon and a second magnet affixed thereto is also disclosed herein. The gate is pivotally affixed to the hinges and is movable in an arc between a first position when no flow impinges upon the gate and the first and second magnets are coupled together and a second position when flow does impinge upon the gate and the first and second magnets are not coupled together. A filter housing includes a sensor therein for sensing the presence of the gate and the first magnet when the gate is in the second position. The filter performance indicator accurately distinguishes between flow and no flow conditions. The gate includes a conically disposed structure extending from the rear side or end thereof which coacts with a cylindrically extending passageway which extends from the filter boundary. A method of making a water filtration device is also disclosed and comprises the steps of: attaching end caps to the filter; inserting the filter within a filter housing; aligning the filter within the filter housing; inserting a portion of a gate into corresponding receptacles on one end of one of the end caps previously affixed to the filter; inserting a sensor and electronic package into an open end of a filter housing end cap; affixing the filter housing end cap to the filter housing forming a chamber between a closed end of the filter housing end cap and the one end of one of the end caps; and, affixing a front housing to the filter housing. The step of attaching end caps to said filter may be performed with adhesive. And, the steps of affixing the end cap of the filter housing, affixing the filter housing end cap to the filter housing and affixing the front housing to the filter housing may be performed by an ultrasonic welding process or one of the other welding processes identified herein. It is an object of the present invention to provide a water filtration device which is disposable and provides an indication as to when the filter should be disposed. It is a further object of the present invention to provide a water filtration device which is small in size and which resides substantially rearwardly with respect to the faucet to which it is mounted. It is a further object of the present invention to provide a water filtration device which is self-contained and which does not require maintenance and, in fact, which cannot be maintained because the parts thereof are non-removably affixed together or non-removably contained therein. It is an object of the present invention to provide a water filtration device at reasonable cost which is disposable and which is faucet mounted. It is an object of the present invention to provide a water filtration device which includes a swinging gate having a magnet therein which in combination with a sensor and an electronic package provides a visual indication as to the status or performance of the filter. It is an object of the present invention to provide a-water filtration device which includes two filtered outlets. It is an object of the present invention to provide a water filtration device which includes a valved outlet with the valve operated by a lever. It is an object of the present invention to provide a water filtration device which includes an outlet having a rotatably mounted fountain head. It is an object of the present invention to provide a water filtration device which includes a lever actuated fountain. It is an object of the present invention to provide a gate which includes a magnet used to provide positional information about the position of the gate. It is an object of the present invention to provide a reliable gate position sensing system which accurately distinguishes between flow and no flow conditions. These and additional objects will become apparent when reference is made to the Brief Description of the Drawings, Description of the Invention and Claims which follow hereinbelow. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded assembly view of a first embodiment of the water filtration device. FIG. 1A is an exploded assembly view of a third embodiment of the water filtration device with a different left end cap and a second magnet employed. FIG. 2 is a perspective view of a first embodiment of the water filtration device. FIG. 2A is a perspective view of a first embodiment of the water filtration device with the handle of the valve pulled forward. FIG. 3 is a cross-sectional view of the first embodiment of the water filtration device taken along the lines 3-3 of FIG. 2. In FIG. 3 the filter is not operating as no water is being directed into it. FIG. 3A is an enlargement of a portion of FIG. 3. FIG. 3B is a cross-sectional view of the first embodiment of the water filtration device with the fountain lever depressed and with water flowing through the filter. FIG. 3C is an enlargement of a portion of FIG. 3B. FIG. 3D is a cross-sectional view of the first embodiment of the water filtration device similar to FIG. 3 with an O-ring used as an additional seal for the filter subassembly. FIG. 3E is a cross-sectional view of a third embodiment of the water filtration device with a different left end cap and a second magnet employed. FIG. 3F is a cross-sectional view of a third embodiment of the water filtration device with a different left end cap and a second magnet employed and with the fountain lever depressed and with water flowing through the filter. FIG. 3G is a cross-sectional view of a third embodiment of the water filtration device with a different left end cap and a second magnet employed and with the fountain lever not depressed and with no water flowing through the filter. FIG. 4 is an enlargement of the front housing of the first embodiment of the water filtration device. FIG. 4A is a cross-sectional view of the front housing taken along the lines 4A-4A of FIG. 4. FIG. 4B is a cross-sectional view of the front housing taken along the lines 4B-4B of FIG. 4. FIG. 4C is a top view of the front housing of the first embodiment. FIG. 4D is an enlarged rear perspective view of the front housing of the first embodiment. FIG. 4E is a cross-sectional view of the rotatable collar (faucet adapter) and the lock collar which is secured to the front housing. FIG. 4F is a cross-sectional view of the aerator mounted into the front housing. FIG. 4G is a cross-sectional view taken along the lines 4G-4G of FIG. 2 with the flow diverter valve inserted in the front housing in a first position, bypass position. FIG. 4H is a cross-sectional view taken along the lines 4H-4H of FIG. 2A with the flow diverter valve inserted in the front housing in a second position which directs flow into the filter. FIG. 5 is a front perspective view of the filter housing of the first embodiment of the water filtration device. FIG. 5A is a front view of the filter housing of the first embodiment of the water filtration device. FIG. 5B is a cross-sectional view of the filter housing taken along the lines 5B-5B of FIG. 5A. FIG. 5C is a cross-sectional view of the filter housing taken along the lines 5C-5C of FIG. 5A. FIG. 5D is a cross-sectional view of the filter housing taken along the lines 5D-5D of FIG. 5A. FIG. 5E is a bottom view of the filter housing of the first embodiment of the water filtration device. FIG. 5F is a left side view, the open end view, of the filter housing of the first embodiment of the water filtration device. FIG. 6 is a perspective view of the valve and its handle which are used in both the first embodiment and the second embodiment of the water filtration device. FIG. 6A is a perspective view of the other side of the valve and its handle of FIG. 6. FIG. 7 is a perspective view of the electronic package (electric circuit), sensor and light emitting diode used in the first and second embodiments of the water filtration device. FIG. 7A is a side view of the electronic package (electric circuit), sensor and light emitting diode package of FIG. 7. FIG. 8 is a side view of the housing end cap. FIG. 8A is a perspective view of the other side, i.e., the wetted side, of the housing end cap illustrated in FIG. 8. FIG. 9 is a front view of the gate of the first embodiment. FIG. 9A is a cross-sectional view taken along the lines 9A-9A of FIG. 9. FIG. 9B is a front view of another embodiment of the gate having a conical protrusion extending therefrom as well as a cylindrical extrusion extending therefrom. FIG. 9C is a cross-sectional view of the gate taken along the lines 9C-9C of FIG. 9B. FIG. 9D is a rear view of the embodiment of the gate illustrated in FIG. 9B. FIG. 10 is a front view of the left end cap of the filter. FIG. 10A is cross-sectional view of the left end cap of the filter taken along the lines 10A-10A of FIG. 10. FIG. 10B is a front view of another embodiment of the left end cap of the filter. FIG. 10C is a cross-sectional view of the embodiment of the left end cap of the filter of FIG. 10B taken along the lines 10B-10B. FIG. 11 is a perspective view of the plunger used in conjunction with the lever and elastomeric ball valve. FIG. 11A is a another perspective view of the plunger used in conjunction with the lever and elastomeric ball valve. FIG. 11B is a top view of the plunger. FIG. 11C is a cross-sectional view of the plunger taken along the lines 11C-11C of FIG. 11B. FIG. 11D is a cross-sectional view taken along the lines 11D-11D of FIG. 11B. FIG. 12 is a front view of the ball valve. FIG. 12A is a cross-sectional view taken along the lines 12A-12A of FIG. 12. FIG. 13 is a top view of the lever used to operate the plunger of the first embodiment. FIG. 13A is a cross-sectional view of the lever taken along the lines 13A-13A of FIG. 13. FIG. 13B is a perspective view of the underside of the lever of FIG. 13. FIG. 14 is a front view of the fountain head. FIG. 14A is a cross-sectional view taken along the lines 14A-14A of the fountain head of FIG. 14. FIG. 15 is an exploded perspective view of a second embodiment of the invention. FIG. 15A is an exploded perspective view of a fourth embodiment of the invention. FIG. 16 is a perspective view of a second embodiment of the water filtration device. FIG. 16A is a perspective view of a second embodiment of the water filtration device with the valve handle pulled forward. FIG. 17 is a cross-sectional view of the second embodiment of the water filtration device taken along the lines 17-17 of FIG. 16. FIG. 17A is a cross-sectional view of the second embodiment of the water filtration device similar to FIG. 17 except the gate is shown rotated clockwise in the flow condition. FIG. 17B is a cross-sectional view of the fourth embodiment of the water filtration device. FIG. 17C is a cross-sectional view of the fourth embodiment of the water filtration device with the gate shown rotated into the open position. FIG. 18 is a perspective view of the front housing of the second embodiment. FIG. 18A is a cross-sectional view taken along the lines 18A-18A of FIG. 18. FIG. 18B is a cross-sectional view taken along the lines 18B-19B of FIG. 18. FIG. 18C is a top view of the front housing of the second embodiment. FIG. 18D is a rear perspective view of the front housing of the second embodiment of the water filtration device. FIG. 18E is a cross-sectional taken along the lines 18E-18E of FIG. 16 with the flow diverter valve inserted in the front housing in a first position, bypass position. FIG. 18F is a cross-sectional view taken along the lines 18F-18F of FIG. 16A with the flow diverter valve inserted in the front housing in a second position which directs flow into the filter. FIG. 19 is a front perspective view of the filter housing of the second embodiment of the water filtration device. FIG. 19A is a bottom view of the of the filter housing of the second embodiment of the water filtration device. FIG. 19B is a cross-sectional view taken along the lines 19B-19B of FIG. 19A. FIG. 19C is a cross-sectional view taken along the lines 19C-19C of FIG. 19C. FIG. 19D is a left side view, the open end view, of the filter housing of the second embodiment of the water filtration device. FIG. 20 is a front side view of the end cap of the housing of the second embodiment of the water filtration device. FIG. 20A is a right side view of the end cap of FIG. 20. FIG. 20B is a perspective-view of the end cap of FIG. 20. FIG. 20C is a view of the left side of the end cap of FIG. 20. FIG. 20D is another perspective view of the end cap. A better understanding of the drawings will be had when reference is made to the Description of the Invention and Claims which follow hereinbelow. DESCRIPTION OF THE INVENTION Referring to FIG. 1, an exploded assembly view of a first embodiment of the water filtration device 100, the various components of the single-use faucet mounted water filter are shown. Filter 113 is illustrated having a longitudinal bore 129 therethrough. Filter 113 is illustrated without a filter pre-wrap in this view but such a pre-wrap 495 is specifically within the scope of this invention and is illustrated in FIGS. 4G and 4H. The filter is preferably a carbon block but may be a fiber bundle or granular activated carbon. Further, the carbon block may include bacteriastic materials, ion exchange resins and zeolites to assist in its filtration activity. End caps 114 and 115 are affixed to said filter with a hot melt adhesive applied to the entire mating surfaces of end caps 114 and 115 including but not limited to the dowel portions thereof such as dowel 130A on right end cap 130. Once filter 113 is affixed to end caps of filter 114, 115, the subassembly is inserted into the filter housing 101. End caps 114, 115 include peripheral seal portions which seal annulus 301. See FIG. 3 for example. O-rings 375, 376 ensure that water entering annulus 301 flow through filter 113 and does not bypass the end caps 114, 115 and migrate into chamber 350. See, FIG. 3D. To ensure that the subassembly is properly oriented, gate hinges 132, 132A must be aligned in relation to a mark 160 on the filter housing as the subassembly is inserted into the filter housing 101. Gate hinges 132, 132A are properly positioned when their axis is parallel to the earth or parallel to a tangent of the earth's surface. Referring to FIG. 5F, the left side view (open end view) of the filter housing: 101 of the first embodiment of the water filtration device, the concave right side wall 508 of the filter housing 101 is illustrated along with molded ribs 515. In this the first embodiment the diameter of the filter housing 101 is approximately 1.6 inches and the length of the filter housing as viewed, for example, in FIGS. 5 and 5A, is approximately 4.2 inches. Other dimensions may be utilized in the construction of water filtration devices as taught herein without departing from the spirit and scope of the invention. When the filter subassembly is inserted into. the filter housing the right end cap abuts ribs 515. Gate 118 is rotatably affixed to gate hinges 132, 132A by inserting prongs or knobs 133, 133A in the hinges. Knobs or prongs 133, 133A are snap-fit into apertures in the hinges 132, 132A enabling rotation of the gate 118 when water pushes against it as it exits the filter. As will be explained in more detail hereinafter, gate 118 swings (rotates) in a clockwise direction about its axis of rotation (see FIGS. 3B and 3C) upon the application of pressure caused by water flow through the filter 113 and the longitudinal bore 129 therein. Referring to FIGS. 1 and 3, gate 118 includes a magnet 117 which is press fit into a recess 134 in the gate and hermetically sealed with either hot melt adhesive or potting compound. FIG. 3 is a cross-sectional view 300 of the first embodiment of the water filtration device taken along the lines 3-3 of FIG. 2. Presence or absence of magnet 117 is sensed by reed switch (reed relay) 135. Housing end cap 102 includes spacers 142 and 143. See FIG. 8A, a perspective view of the end cap to best view the spacer 142 which is not well illustrated in the exploded assembly view of FIG. 1. Spacers 142, 143 assist in correctly spacing the housing end cap 102 with respect to the left end cap 114 of the filter. Once housing end cap 102 is inserted into the filter housing 101, spacers 142, 143 ensure that the filter subassembly comprising the filter 113, left end cap 114 and right end cap 115 does not migrate leftwardly (See FIG. 3) too far and remains in proximity to the mold ribs 515 of the interior of the housing. Housing end cap 102 includes a tapered portion 190 for insertion into the filter housing 101. A chamber is formed between the end cap 114 and the closed end 803A of the housing end cap 102. See, FIG. 3. Water is expelled from passageway 141 in the left end cap 1 14 of the filter housing and exerts a force against gate 118 causing it to rotate in a clockwise direction. As gate 118 rotates in the clockwise direction the magnet 117 is urged toward the reed switch 135 (reed relay) causing it to effectively close which starts the electronic timer within electronic package 112 to continuously measure the time when the magnet 117 is in proximity to the switch. The electronic package (electric circuit or integrated circuit) measures the cumulative time of flow through the filter and outputs signals to the light emitting diode (LED) indicating filter performance. The LED indicates three colors representative of cumulative filter usage one of which indicates that the water filtration device should be discarded. The electric circuit outputs three discrete signals to the light emitting diode. The electronic package is secured in a dry well 170 which in turn is secured and closed by end plate 116. After the housing end cap 102 is installed it is welded to the filter housing 101. The end plate 116 is glued or ultrasonically welded to the housing end cap 102. That is, the housing end cap 102 is welded to the filter housing and the end plate 116 is welded or glued to the housing end cap 102. Reference numeral 139 represents the raised portions of the end plate 116 which are ultrasonically welded or glued to the housing end cap 102. Referring to FIG. 3 again, reference numerals 302, 303, 130, 131 signify peripheral edges or portions of the end caps 114, 115 of the filter which slidingly engage and seal against the interior walls of the filter housing 101. Referring to FIG. 3D, elastomeric seal 375 acts as an additional optional seal which resides between peripheral edge portions 302 and 131 and elastomeric seal 376 acts as an additional optional seal which resides between peripheral edge portions 303 and 130. Still referring to FIG. 1, aperture 137 permits light emitting diode 136 which stems from the electronic package 112 to pass therethrough. A small amount of potting compound may be used around the light emitting diode to seal any space between the diode and the aperture 137 when the light emitting diode is installed in place. The electronic package 112 and the substrate upon which the electronics are mounted are housed in a dry space in the housing end cap 102. Referring to FIGS. 1 and 5, the filter housing 101 including its inlet 125, filtered outlet 107A, and filtered outlet 180 are illustrated. Filtered outlet 107A always expels filtered water whenever water enters the filter housing inlet 125. See, FIG. 4H. Inlet 125 is generally cylindrically shaped and includes a recess 126 for receiving an O-ring seal 502 and a passageway 505 for conducting unfiltered water to the interior of the filter housing so that it can be filtered by filter 113. Filter 113 is a carbon block filter and it is necessary that the water to be filtered have a certain residence time in contact with the filter so that impurities therein can be removed. The preferred materials of the front housing 103, filter housing 101 and housing end cap 102 are ABS (acrylonitrile butadiene styrene) plastic although other plastics may be used. The preferred adhesive to be used for securing the end caps 114, 115 to the filter is a hot melt adhesive. The gate material is HDPE (high density polyethylene). End caps 114, 115 are also HDPE and the material used for sealing. Lever 122 is preferably an acetyl material. FIG. 5 is a front perspective view 500 of the filter housing 101 of the first embodiment of the water filtration device, i.e., a bathroom filter. FIG. 5 illustrates an inlet surface 504 adapted to receive a corresponding mating surface 190 from the housing end cap 102. See, FIG. 1 to identify the corresponding mating surface 190 on the housing end cap 102. Referring again to FIG. 5, the filter housing 101 includes a recessed region 501 for receiving the front housing 103 as best seen in FIGS. 1, 2 and 4G. Engagement pins 127, 128 assist in positioning the front housing 103 with respect to the recessed region 501 for ultrasonic welding thereto. It is the ultrasonic welding of the front housing 103 to the filter housing which secures the parts together and makes them into an integral unit. Pins 127, 128 fit snugly into corresponding receptacles 420, 419 in the front housing. Referring to FIG. 4D, a rear perspective view 400D of the front housing of the first embodiment (bathroom filter) is illustrated along with the receptacles 420, 419. Reference numerals 415, 417 and 418 indicate mold cavities which are formed as a part of the molding process of the front housing 103. Joint 421 is welded to the filter housing 101. Further, referring to FIGS. 4G and 5, O-ring seal 502 which resides in recess 126 mates with cylindrical recess 410 in the front housing 103 as illustrated in FIG. 4D to prevent leakage of water as it is being directed into the filter housing as will be explained hereinbelow. FIG. 5A is a front view 500A of the filter housing 101 of the first embodiment of the water filtration device. The right end 508 is closed and is convexly shaped when viewed from the outside of the filter housing. Viewing the interior of the right end 508 as in FIG. SF, it is shaped concavely. During assembly of the device, the water filter 113 with end caps attached thereto is inserted from the left side, the open side, of the filter housing 101. FIG. 5B is a cross-sectional view 500B of the filter housing taken along the lines 5B-5B of FIG. 5A. FIG. 5B provides a good illustration of recess 126 in inlet 125 and of pin 128. Outlets 180 and 107A are also illustrated in FIG. 5B. FIG. 5C is a cross-sectional view 500C of the filter housing taken along the lines 5C-5C of FIG. 5A. Outlet port 180 is illustrated in cross-section as having two diametrical sections 503 and 506. Likewise, outlet port 107A is illustrated as having two diametrical sections 519 and 507. FIG. 5D is a cross-sectional view 500D of the filter housing taken along the lines 5D-5D of FIG. 5A. FIG. 5D illustrates the recessed region 501 in filter housing 101. Also illustrated in FIG. 5D is the inlet 125 having passageway 505 therein. FIG. 5E is a bottom view 500E of the filter housing of the first embodiment of the water filtration device illustrating diametrical portions 507, 519 of outlet 107A. FIG. 5E illustrates that outlet 107A resides generally forwardly in the filter housing. Outlet 107A includes spout 107 which is affixed through an ultrasonic weld or by gluing same to the filter housing 101. See, FIG. 1. FIG. 2 is a perspective view 200 of a first embodiment of the water filtration device. Referring to FIGS. 1, 2,4, and 4E, collar lock 105 is inserted within collar 104 and is welded to surface 401 of front housing 103. FIG. 4 is an enlargement 400 of the front housing of the first embodiment of the water filtration device. FIG. 4E is a cross-sectional view 400E of the collar 104, collar lock 105 and screen 110. Screen 110 includes an elastomeric generally circular periphery and a convexly shaped screen portion 110A. Collar 104 may rotate with respect to collar lock 105 in the connection and disconnection process with a faucet. The faucet (not shown) seals on the elastomeric portion of the screen 110. Screen 110 assists in removing large particulate matter. Referring still to FIG. 2, front housing 103 is illustrated in its assembled condition welded to the filter housing 101. Valve and valve handle 108 are illustrated in the first or bypass position. FIG. 4G is a cross-sectional view 400G taken along the lines 4G-4G of FIG. 2 with the flow diverter valve 108 inserted in the front housing in a first position, bypass position. Flow arrow 470 indicates the path flow will take through the front housing when the water bypasses the filter. FIG. 4H is a cross-sectional view 400H taken along the lines 4H-4H of FIG. 2A with the flow diverter valve 108 inserted in the front housing in a second position which directs flow into the filter. Flow arrow 471 indicates the path of flow through the front housing when the diverter valve 108 is rotated counterclockwise when viewing FIG. 4H to a second position. Referring to FIG. 2A, valve and valve handle 108 are pulled forward to the second position when it is desired to filter the water. Referring again to FIGS. 4G and H, elastomeric seal 450 is illustrated as sealing passageways 603 and 610 in valve 108. Passageway 610 is formed by wall 611 and passageway 603 is formed by wall 605 which is horn shaped. See, FIG. 6, a perspective view 600 of the valve and its handle 108 which are used in both the first embodiment and the second embodiment of the water filtration device. The handle portion of the valve includes an insert 109 which may glued to a corresponding recess 109A in the handle. See, FIG. 1. FIG. 4A is a cross-sectional view 400A taken along the lines 4A-4A of FIG. 4 illustrating the generally cylindrical wall 401 to which the collar lock 105 is welded. FIG. 4E is a cross-sectional view 400E illustrating the collar lock 105 secured to the wall 401 with the collar 104 being rotatable and movable slightly vertically for engagement with a faucet. Screen 110 is also illustrated in FIG. 4A. Referring again to FIG. 4A, valve 108 is not shown therein so as to view the valve stop 407 which controls the rotation of the valve between its first (bypass position) and its second (filter) position. Valve cavity 430 is tapered as it extends inwardly as indicated by circular lines 412 and 431. See, FIGS. 4A and 4B. Ports 403 and 408 join to form a water inlet to the valve cavity 430. Water outlet 409 conveys water to be filtered when the front housing is nonremovably affixed to the filter housing 101 and the valve 108 is in its second position. FIG. 4B is a cross-sectional view 400B taken along the lines 4B-4B of FIG. 4 and also illustrates the taper of valve cavity 430. Referring again to FIGS. 4A and 4B, recess 416 is illustrated for receiving a seal 640 on the valve 108 illustrated in FIG. 6. Bypass port or passageway 414 is illustrated in FIGS. 4A and 4B. Stop 407 is also illustrated in FIG. 4B as is recess 410 for receiving inlet 125 of the filter housing 101. Referring to FIG. 4A mold aperture 415 from the molding process is illustrated in cross section. FIG. 4C is a top view 400C of the front housing 103 of the first embodiment and also illustrates the ports 403 and 408. FIG. 4 is an enlargement 400 of the front housing 103 of the first embodiment of the water filtration device illustrating wall 401 to which the collar lock 105 is welded. Ports 403, 408 in floor 404 are shown in the top of the housing as are mold openings 402. Recess 416 in valve cavity 431 is shown as is rim 406 which is welded to the filter housing 101. Recess 416 receives seal 640 on valve 108 so as to prevent leakage about valve 108. Referring again to FIGS. 1 and 4A, bottom portion 103A of the front housing is illustrated along with bore 422 having stepped portions 429 and 413. Bore 422 receives aerator assembly 111/111A and spout 106 secures the aerator assembly in place as it is welded to the bottom portion 103A of the housing 103. See, FIG. 4F, a cross-sectional view 400F of the aerator assembly 111/111A mounted into the front housing. Referring to FIGS. 3-3D, reference numerals 302, 303, 131, and 130 indicate sliding engagement of the filter end caps 114, 115 with the filter housing 101. Referring again to FIGS. 1 and 3, second outlet 180 in the filter housing 101 is disclosed. Alignment mark 160 is also illustrated well in FIG. 1 and it is this mark which is used during assembly to ensure that the left filter end cap 114 and hinges 132/132A are positioned such that the axis of the hinges are parallel to the earth enabling gate 118 to swing freely upon the application of pressure thereto and not to bind. Plunger 120 having a passageway 120A therein fits somewhat snugly within second outlet 180 and is slidingly movable therein. Lever 122 resides in engagement with the plunger 120 such that the plunger 120 and lever 122 move together. Referring to FIG. 2, lever 122 is hinged and pivotal on prongs or protrusions 138 of the housing end cap 102. Like lever 108, lever 122 has a decorative insert 123 which resides in a corresponding recess. Fountain head 119 resides in and through passageway 122A in lever 122. Fountain 119 includes a passageway 119A in communication with passageway 120A in plunger 120. Passageway 120A is exposed to fluid under pressure in chamber 350 when the plunger is depressed by lever 122. Plunger 120 includes a shoe portion 1104. FIG. 11 is a perspective view 1100 of the plunger 120 used in conjunction with the lever 122 and elastomeric ball valve 121. Plunger 120 includes a cylindrical portion 1103 and a shaft 1105 with a shoe 1104 on the end thereof. A flat extending portion 1101 of the plunger resides against a corresponding surface of the lever 122. A taper 1102 leads to passageway 120A. FIG. 11A is a another perspective view 1100A of the bottom side of the plunger 120 used in conjunction with the lever 122 and elastomeric ball valve 121. Contoured side edge portion 1150 of plunger 120 engages lever 122. Passageway 120A and bottom side 1106 of the flat extending portion 1101 are best viewed in FIG. 11A. Spring 124 is operable between the bottom side 1106 of plunger and a lip 570 of the filter housing. See FIG. 3, a cross-sectional view 300 of the first embodiment of the water filtration device taken along the lines 3-3 of FIG. 2. In FIG. 3, the filter is not operating meaning that the diverter valve 108 is in the bypass (first) position. FIG. 11B is a top view 1100B of the plunger 120 illustrating the passageway 120A. FIG. 11C is a cross-sectional view 1100C of the plunger 120 taken along the lines 11C-11C of FIG. 11B. FIG. 11D is a cross-sectional view 1100D taken along the lines 11D-11D of FIG. 11B. FIG. 12 is a front view 1200 of the ball valve 121. FIG. 12A is a cross sectional view 1200A taken along the lines 12A-12A of FIG. 12. Shoe 1104 is covered by elastomeric valve 121 which includes a cavity which is substantially reciprocally shaped to the shape of the shoe. Elastomeric valve of boot 121 includes a surface 1202 which engages the interior of the filter housing around passageway 506. See, FIGS. 5C and 3. FIG. 3A is an enlargement 300A of a portion of FIG. 3 illustrating the valve 121 engaged with the inner wall of housing 101. Spring 124 is operable between filter housing 101 and plunger 120 and urges the plunger and the lever upwardly when viewing FIGS. 3 and 3A. Still referring to FIG. 3, an annular space 301 between the filter 113 and the filter housing 101 is illustrated. Water occupies this annular space 301 during operation of the filter. Water resides in this annulus and flows through filter 113 into passageway 129 and out port 141 impinging upon gate 118 rotating it clockwise. When the water filtration device of the first embodiment is operable, water will be expelled from both outlets 107A and 180 if lever 122 is depressed. If the lever is not depressed then elastomeric valve 121 is seated against the curved inner surface of the filter housing 101 and water will be expelled just from the outlet 107A. Valve 121 is preferably elastomeric but may be made of other materials such as metal. Similarly, the filter housing may be made of metal if desired and the valve can be made of metal as well. FIG. 3 illustrates spacer 142 extending from the closed end 803A of housing end cap 102 near the filter left end cap 114. FIG. 8 is a side view 800 of housing end cap 102. Closed end 803 is a wall or boundary between the wetted chamber 350 and the electronic package 112 and sensor 135. Guide ribs 801, 802 and 810 enable placement of the generally-rectangularly shaped electronic package within the drywell 811 of the housing end cap 102. End plate 116 fits over the opening 811 of the end cap and is either welded or glued 139 to the end cap for hermetic sealing thereof. During assembly the light emitting diode 136 is carefully placed within the aperture 137 first followed by the electronic package 112 which is placed within opening 811. FIG. 8A is a perspective view 800A of the other side, i.e., the wetted side, of the end cap illustrated in FIG. 8. Sloped surface 190 which is welded to filter housing 101 is illustrated in FIG. 8A. FIG. 3B is a cross-sectional view 300B of the first embodiment of the water filtration device with the fountain lever 122 depressed and valve 121 off its seat. It will be noticed that plunger 120 bends slightly when lever 122 is depressed. This bending tends to seal the passageway denoted by reference numeral 506. Gate 118 is shown rotated clockwise due to water flow out of passageway 141. In this position, gate 118 and magnet 117 are in proximity to reed switch 135. FIG. 3C is an enlargement 300C of a portion of FIG. 3B and illustrates the flow path 391 of water past valve 121, through passageway 120A of plunger 120 and through passageway 199A of fountain 119. It will be noticed in FIGS. 3, 3A, 3B and 3C that outlet 107A is not shown therein as it is located fore (ahead) with respect to the cross-section of these drawing figures. FIG. 6 is a perspective view 600 of the valve 108 and its handle which are used in both the first embodiment and the second embodiment of the water filtration device. FIG. 6 illustrates the underside (the side that is not exposed) when viewing FIG. 2. Reference numeral 612 illustrates a cavity from the molding process. Reference numeral 609 indicates the handle portion of the valve 108 and reference numeral 608 indicates the other or second end of the valve 108. Ridges 602 engage stop 407 to limit the rotation of the valve between its first bypass position and its second filter position. A horn shaped passageway 603 is formed by wall 605. Wall 606 creates an annulus 604 in which a seal (not shown in FIG. 6) is positioned. A seal 450 is positioned in annulus 604 as indicated in FIGS. 4G and 4H. A groove 607 resides in the valve 108 for receiving a seal (not shown in FIG. 6) which prevents leakage of water from the valve 108 when it inserted in the front housing 103. FIG. 6A is a perspective view 600A of the exposed side of the valve and its handle 108 as viewed in FIG. 2. FIG. 6A illustrates seal 640 in groove 607 for sealing the valve 108 which is snap fit in the front housing. FIG. 7 is a perspective view 700 of the electronic package 112, battery 701, sensor 135, leads 702, 703 and light emitting diode 136 used in the first and second embodiments of the water filtration device. In the preferred embodiment sensor 135 is a reed switch also known as a reed relay. However, those skilled in the art will readily recognize that different sensors based on capacitance principles, piezoelectric principles, or induction principles may be employed with some modifications. FIG. 7A is a side view 700A of the electronic package illustrated in FIG. 7. FIG. 9 is a front view 900 of gate 118 of the first embodiment. Recess 134 receives magnet 117 which actuates reed switch 135 when in proximity therewith. Prongs or knobs 134 interengage corresponding hinges 134 as illustrated in FIGS. 1 and 3. FIG. 9A is a cross-sectional view 900 taken along the lines 9A-9A of FIG. 9. FIG. 9A illustrates the contour of the gate 118 which includes front 903 and rear 902 surfaces. Sloping surface 904 diverges to body 905 having recess 134 in which magnet 117 is housed. Locks 901 secure magnet 117 in place. The magnet is installed by simply pushing on the magnet to orient it past the locks 901 which are plastic and somewhat malleable enabling insertion of the magnet into the plastic. The magnet is then hermetically sealed with potting compound. FIG. 10 is a front view 1000 of the left end cap 114 of the filter 113. Hinges 132/132A are illustrated in FIGS. 10 and 10A. FIG. 10A is cross-sectional view 1000A of the left end cap of the filter taken along the lines 10A-10A of FIG. 10 illustrating the hinges 132/132A, passageway 141, dowel 1001, and protrusions 1002 and 1003 which slidingly seal with respect to the filter housing. Peripheral end portion such as the one denoted by reference numeral 131 are relatively soft and seal against the interior of the filter housing. FIG. 13 is a top view 1300 of the lever 122 used to operate the plunger 120 of the first embodiment. Reference numeral 1301 indicates a recess in which insert 123 is secured by adhesive. Apertures or hinges 140/140A engage prongs or protrusions 138 for pivoting as previously described. FIG. 13A is a cross-sectional view of the lever 122 taken along the lines 13A-13A of FIG. 13 also illustrates the aperture 140A. Cavities 1302 and 1303 are illustrated in FIG. 13A. Cavity 1303 fits over flat portion 1101 of plunger 120. See, FIG. 11. FIG. 13B is a perspective view 1300B which illustrates the underside of the lever 122 of FIG. 13. Cavity 1303 and wall 1304 of cavity 1303 are illustrated. Flat portion 1101 of plunger 120 fits into cavity 1303. FIG. 14 is a front view 1400 of the fountain head 119 illustrating flanges 1401 and 1402. FIG. 14A is a cross-sectional view 1400A taken along the lines 14A-14A of the fountain head 119 of FIG. 14. Flange 1402 is snap-fit into place in lever 122 as is best seen in FIG. 3. Fountain head 119 is made of plastic. Spring 124 is illustrated in FIG. 1 as operable between seat 570 and surface 1106. See, FIGS. 3, 5C and 11C. FIG. 3 illustrates valve 121 seated against seat 330. FIGS. 1-14 are directed toward the first embodiment of the invention. Some of the uses of the first embodiment of the invention are in bathrooms, hotel and motel rooms. The device disclosed is small and convenient for storage on vacations and business trips. FIGS. 15-20 are directed toward the second embodiment of the invention. Use of the second embodiment include kitchen and bar uses. Both embodiments are designed such that the filter sits rearwardly with respect to the faucet so that access to the faucet and the filter is permitted. The reference numerals used in FIG. 15 correspond generally to the reference numerals used in FIG. 1 such that for example reference numerals 101 and 1501 both indicate filter housings. FIG. 15 is an exploded perspective view 1500 of a second embodiment of the invention. Filter housing 1501 may have, for example, a diameter of 2.40 inches and a length of approximately 3.90 inches. One of the principal differences in the kitchen filter of the second embodiment is that it has only one filtered outlet 1507A whereas the bathroom unit has two filtered outlets 107A and 180. Filters 1513 and 113 may be pre-wrapped 495 using a hot seal method. See, FIGS. 4G and 4H. Adhesive is applied to the filter end caps 1514, 1515, then attached to the filter after which the subassembly is inserted into the filter housing. Peripheral seal portions of end caps 1514, 1515 seal the filter. Optionally, O-rings 375, 376 may be used to seal the filter so as to prevent unfiltered water from entering chamber 1750. See, FIG. 17. As in the case of the bathroom filter, the aerator assembly 1511 and spout 1506 are affixed in the front housing 1503 as previously illustrated. As also in the case of the bathroom filter, the collar lock 1505 is welded to the front housing 1503 and collar 1504 is permitted to rotate with respect to the collar lock. The screen assembly is inserted into the assembly atop the collar lock. Gate 1518 is slightly dimensionally different than the gate 118 previously described but it functions in the same way as gate 118. Spacers 1542 and 1543 extend from end cap 1502 and serve to ensure that gate 1518 remains in alignment. Electronic package 112 is the same package used in the first embodiment. Reed switch 135 (or reed relay as it sometimes known) senses the proximity of magnet 1517 and the electronic package measures the total time of flow. Instead of a reed switch which is a magnetically coupled device, a capacitance based device or a pressure-sensitive device may be used instead. The pressure sensitive device would have to mounted in the closed end of the housing end cap 1502. Valve 108 illustrated in FIG. 15 is the same valve used in the bathroom filter of the first embodiment. Spacers 1542, 1543 of the housing end cap 1502 assist in ensuring that the filter subassembly is in place. Referring to FIG. 17, a gap (unnumbered) exists between the spacer 1543 and the end cap 1514 of the filter. Spacer limits the movement of the filter subassembly such that it cannot move leftwardly too far before engaging the spacers. End plate 1516 is glued or welded to the housing end cap 102. Housing end cap 102 is glued or welded to the filter housing 1501. FIG. 16 is a perspective view 1600 of the second embodiment of the water filtration device. FIG. 17 is a cross-sectional view 1700 of the second embodiment of the water filtration device taken along the lines 17-17 of FIG. 16. FIG. 17A is a cross-sectional view 1700A of the second embodiment of the water filtration device similar to FIG. 17 except the gate 1518 is shown rotated clockwise in the flow condition. Annulus 1701 is illustrated in FIG. 17A. Water resides in this annulus and flow thru filter 1513 into passageway 1529 and out port 1541 impinging upon gate 1518 rotating it clockwise. Referring to FIGS. 15 and 17, filter end caps 1514 and 1515 have peripheral end portions (i.e., 1531 and 1530) which are seals which seal against the interior diameter of the filter housing 1501. Although not shown in FIG. 17, optional elastomeric O-ring seals similar to 375, 376 may be used between the peripheral end seals as illustrated in FIG. 3D. FIG. 18 is a perspective view 1800 of the front housing of the second embodiment. FIG. 18 employs reference numerals like FIG. 4. FIG. 18A is a cross-sectional view taken along the lines 18A-18A of FIG. 18. Reference numeral 1801 indicates the wall to which the collar lock 1505 is welded and reference numeral 1804 indicates the floor upon which the collar lock 1804 sits at the time it is welded. Mold recesses 1802 are from the molding process. Groove or recess 1816 receives the seal from the valve 108. Cavity 1831 receives the valve 108. Referring to FIG. 18A, stop 1807A is illustrated which engages ridges 602 on valve 108. Stop 1807A is also illustrated in FIG. 18B, a cross-sectional view taken along the lines 18B-18B of FIG. 18. Tapered bore 1812 is illustrated by the circular lines in FIG. 18A. Bore 1822 includes stepped portions 1813 and 1829. Inlet 1808 is shown leading to valve cavity 1831. Outlet 1814 and outlet 1809 are also shown in FIG. 18A. When valve 108 is positioned as illustrated in FIG. 18E inlet 1808 is connected to outlet 1814 and the water passes through front housing 1503 and is expelled unfiltered. Flow arrow 1870 depicts the path of flow through front housing 1503. When the valve 108 is positioned as illustrated in FIG. 18F inlet 1808 is connected to outlet 1809 where it is directed into the filter by inlet 1525 of the filter housing 1501. See, FIG. 16A a perspective view of a second embodiment of the water filtration device with the valve handle pulled forward. Flow arrow 1871 depicts the path of flow through front housing 1503 and into inlet 1525 of the filter housing. Referring to FIG. 18B, valve cavity 1831 is illustrated as is stop 1807A and the cross-sectional portion 1807 of the stop. Unfiltered outlet 1814 is also depicted. FIG. 18C is a top view 1800C of the front housing 1503 of the second embodiment. FIG. 18D is a rear perspective view 1800D of the front housing of the second embodiment of the water filtration device. FIG. 18D illustrates receptacles 1819 and 1820 of the front housing which engage pins 1528 and 1527 respectively. Mold recesses from the molding process are indicated by reference numerals 1817, 1818, 1823, 1824 and 1825. Joint 1821 is welded to the filter housing. FIG. 19 is a front perspective view 1900 of the filter housing of the second embodiment of the water filtration device. Surface 1904 engages the corresponding surface on the housing end cap 1502. Recess 1901 engages the perimeter of the front housing. FIG. 19A is a bottom view 1900A of the of the filter housing 1501 of the second embodiment of the water filtration device. FIG. 19B is a cross-sectional view 1900B taken along the lines 19B-19B of FIG. 19A illustrating port 1907 from which filtered water is expelled. FIG. 19C is a cross-sectional view 1900C taken along the lines 19C-19C of FIG. 19C illustrating passageway 1905 in inlet 1525 of the filter housing 1501. FIG. 19D is a left side view 1900D, the open end view, of the filter housing 1501 of the second embodiment of the water filtration device illustrating mold prongs in the end housing. These prongs or ribs 1906 restrict the insertion depth of the filter sub assembly. FIG. 20 is a front side view 2000 of the end cap of the housing 1502 of the second embodiment of the water filtration device. Surface 2007 of the housing end cap engages surface 1904 of the filter housing and is welded or glued thereto. FIG. 20A is a right side view 2000A of the end cap of FIG. 20 illustrating the closed end 2003. FIG. 20B is a perspective view 2000B of the end cap of FIG. 20 illustrating the closed end and spacers 1543, 1542. FIG. 20C is a view 2000C of the left side of the end cap of FIG. 20 illustrating supports 2001, 2002 and 2010 which restrict the movement of the electronic package in place. FIG. 20D is another perspective view 2000D of the end cap illustrating the housing 2011 in which the electronic package resides. To assemble the water filtration devices, insert the aerator into the through spout and then insert the through spout and ultrasonically weld the aerator/spout assembly to the front housing. Place the threaded collar into the seat on top of the front housing and press the lock collar through the threaded collar and seat the lock collar into the housing. Clamp and ultrasonically weld the lock collar to the front housing. Insert the filtered spout into the filter housing and clamp and weld it to the filter housing. Insert the front housing into position with respect to the filter housing and then clamp and ultrasonically weld it to the filter housing. A prefilter may be wrapped around the filter and sealed using the hot seal method. Next, the left and right end caps with adhesive applied to the contact surfaces thereof are inserted in the filter. Uniform pressure is applied to the left and right filter end caps 114, 115, 1514, 1515 to spread the adhesive and allow it to set. Approximate time for applying pressure is 2-5 seconds. The magnet is installed into the gate under the pressure of a person's finger or a tool such as pliers or the equivalent then hermetically sealed in place. Next, the gate 118, 1518 is snapped into the hinges with the magnet facing outwardly. Indicia on the left end cap of the filter subassembly is aligned with a mark or other indicia on the filter housing and the filter subassembly is inserted into the filter housing. Indicia on the housing end cap 102, 1502 is aligned with indicia on the filter housing and inserted therein. Once the housing end cap is in place it is clamped and ultrasonically welded to the filter housing non-removably retaining the filter within the filter housing. The lever is installed by snapping it into place in the valve cavity. To install the end of life electronic package, the light emitting diode is inserted into and through the aperture 137. Optionally, adhesive may be used when installing the diode in the aperture 137 to secure it into position and to ensure that the diode is hermetically sealed. The electronic package is installed into the reservoir in the open end of the housing end cap with the glass reed switch facing inwardly. End plate 116, 1516 is next snap-fit into place to hermetically seal the electronic package. Optionally, adhesive may be used around the perimeter of the end plate to ensure a hermetic seal. Or, the end plates may be welded to the housing end caps. The materials which are ultrasonically welded should be amenable to welding such as ABS or other plastics. FIG. 1A is an exploded assembly view 100A of a third embodiment of the water filtration device with a different left end cap 114A and a second magnet 114B employed. Gate 118A is employed in the third embodiment and can be viewed in cross-section in FIGS. 3E, 3F, and 3G. These figures illustrate a conical protrusion 118B extending rearwardly from gate 118A and partially surrounded by a cylindrically extending protrusion 118C which also emanates from the rearward side of the gate 118A. Cylindrically shaped protrusion 118C is larger in diameter than the cylindrically shaped protrusion or passageway 141A which extends from end cap 114A. FIG. 3E shows the relationship of the diameters of the respective cylindrically shaped extensions 118C, 141A. FIG. 3E is a cross-sectional view 300E of the third embodiment of the water filtration device with a different left end cap 118A and a second magnet 114B employed. Conical protrusion 118B extends from the rearward side of the gate 118A. FIG. 3E illustrates the no flow condition and the gate is in the first position. In this condition magnet 117 which resides in the gate 118A is coupled to magnet 114B which resides in the end cap 114A. It is the coupling effect of the magnets which ensures that the magnet 117 does not unintentionally and improperly actuate the reed switch and indicate a flow condition. Magnets 117 and 114B are attractive magnets and are oriented such that they attract one another. Magnet 117 is secured within the gate 118A and magnet 114B is secured within left end cap 114A. A potting compound or adhesive may be used to secure the respective magnet within the gate 118A and the left end cap 114A. Therefore, as the magnets are attractive the gate is also attracted toward the left end cap when it is in proximity to the left end cap. As flow through the filter exits cylindrical extension 141A with sufficient velocity and force it overcomes the magnetic coupling or attraction of the magnets 117/114B and allows the gate to move in an arc to its second position. When flow is discontinued through the filter, magnets 117/114B will couple when they are sufficiently proximate each to the other. The magnets help ensure that the gate will not unintentionally occupy an intermediate position between the first position and the second position. The magnets ensure that the gate resides in the first position when there is no flow through the filter. End cap 114A is sometimes referred to herein as a filter boundary cap. It is this rearward side 118A which experiences and reacts to the kinetic energy of the water flow emanating from cylindrical passageway 141A of the filter end cap 114A. Conical protrusion 118B resides partially within cylindrical passageway 141A of end cap 114A. Conical protrusion 118B is bounded generally by a cylindrically shaped in cross-section perimeter 118C which assists and focuses the energy of the impinging water when flow is present as illustrated in FIG. 3F. FIG. 3F is a cross-sectional view 300F of the third embodiment of the water filtration device with a different left end cap 114A and a second magnet 114B employed and with the fountain lever depressed and with water flowing through the filter. FIG. 3F illustrates the gate in the second position and flow arrow 391 indicates flow through the filter. FIG. 3G is a cross-sectional view 300G of the third embodiment of the water filtration device with a different left end cap 114A and a second magnet 114B employed and with the fountain lever not depressed and with no water flowing through the filter. FIG. 9B is a front view 900B of another embodiment of the gate having conical protrusion 907 and cylindrical protrusion 906 extending therefrom. FIG. 9C is a cross-sectional view 900C of the gate taken along the lines 9C-9C of FIG. 9B. FIG. 9D is a rear view 900D of the embodiment of the gate illustrated in FIG. 9B. FIG. 10B is a front view 1000B of another embodiment of the filter left end cap 114A. Cylindrically extending passageway 141A extends from the filter end cap 114A. Sometimes herein the filter end cap 114A is referred to as the filter boundary. FIG. 10B illustrates the second magnet 1 14B residing in cavity or housing 114C. The securement of magnet 114B within the filter end cap 114A may be effected as described hereinabove with respect to the magnet which resides in the gate. FIG. 10C is a cross-sectional view 1000C of the embodiment of the left end cap of the filter of FIG. 10B taken along the lines 10B-10B. FIG. 15A is an exploded perspective view 1500A of a fourth embodiment of the invention. FIG. 15A illustrates the filter which is best suited for use in a kitchen. Gate 1518A is illustrated as is the conically shaped protrusion 1518B and the cylindrical shroud or perimeter 1518C. Second magnet 1514B is also shown in perspective in FIG. 15A. FIG. 17B is a cross-sectional view 1700B of the fourth embodiment of the water filtration device. The structure, function and operation of gate 1518A and its magnet 1517 illustrated in FIG. 17B are the same as that described above in connection with the gates and magnets illustrated in FIGS. 3G and 3E. FIG. 17C is a cross-sectional view 1700C of the fourth embodiment of the water filtration device with the gate shown rotated into the open, second position. The structure, function and operation of gate 1518A and its magnet 1517 illustrated in FIG. 17C are the same as that described in connection with FIG. 3F above. The invention has been described herein by way of example only. Those skilled in the art will readily recognize that changes and modifications may be made to the invention without departing from the spirit and scope of the appended claims which follow hereinbelow.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The demand for pure water continues to grow rapidly due to increasing concerns about the quality and safety of tap water, the popularity of water as a beverage (instead of soda and alcohol) and the growing awareness that most people do not drink enough water as prescribed by the medical community. Water is supplied from municipal water systems (many of which are aging), private water systems and wells in the United States. Frequently, this water has poor taste, particulates, unwanted odors and in many cases contaminants contained in it. Municipal water is commonly treated with chlorine to eliminate bacterial contaminants. Chlorine adds what most people feel is an unpleasant taste and odor. Water conditions vary greatly according to the geographic area and therefore travelers may also experience these problems as they visit hotel and motel rooms around the country. It is desirous to remove bad tastes, odors, sediment and contaminants before ingesting the water or using it for cooking food. Water treatment devices of many varieties have proven effective in accomplishing water purification. Generally these devices work through chemical and mechanical actions that remove contaminants and impurities from water. These filters have a finite life. Sediment can eventually clog a filter and chemical reactions realized through adsorption (carbon media) and ion exchange (cation resin) have a limited capacity. U.S. Pat. No. 5,989,425 to Yonezawa et al. discloses a multi-way valve and water purifier. The multi-way valve is disclosed as a small-sized one which may be used with a small-sized water purifier. The device disclosed in the '425 patent is a faucet mounted filter and it is designed for removing and exchanging valve bodies. U.S. Pat. No. 5,017,286 to Heiligman and U.S. Pat. No. Re. 35667 to Heiligman disclose a vertical filter enclosed in a housing and the housing is supported by a duct. The vertical filter may be permanently secured to the filter by hot melt adhesive which renders the filter non-removable. Further, the vertical filter may be pre-wrapped with a porous paper pre-filter. The device disclosed in the '286 patent is a faucet mounted filter. If the filter is glued to the filter housing the filter housing must be removed and discarded together with the filter. A new filter housing (and filter) must then be mounted onto the duct of the diverter valve each time the filter housing is replaced. This involves time consuming labor in the case of each embodiment disclosed in the '286 patent. In one embodiment of the '286 patent, the filter housing is secured by a retaining clip. In another embodiment disclosed in the '286 patent, the male duct of the filter housing is press-fit into an opening in the diverter valve. Alternatively, the male duct of the filter housing may be affixed to the diverter valve by a U-clip, cotter pin or the like. The filter housing as disclosed in the '286 patent is disclosed as residing vertically in front of the faucet. In short, it is not a simple matter to change the filter housing of the device disclosed in the '286 patent. U.S. Pat. No. 5,527,451 to Hembree et al. discloses a faucet mounted filter utilizing a replacement filter cartridge. The replacement filter cartridge resides within a larger rotatable housing which channels water flow either into the filter or through the diverter valve assembly. Hembree et al. also discloses a very complicated flow totalization mechanism which includes porting water to a turbine driven mechanism prior to filtering thereof. U.S. Pat. No. 6,571,960 B2 to Williamson et al. discloses a faucet-mounted water filtration device whose filter housing includes a valve therein and whose filter housing extends longitudinally rearwardly from the point of attachment to the faucet. The filters in Williamson et al. are replaceable filter cartridges. U.S. Pat. No. 6,284,129 B1 to Giordano et al. discloses a rotating a magnetized impeller actuating a reed switch. In each of the foregoing disclosures, the devices disclosed therein are designed for disassembly of some sort as a matter of maintenance of the filtration device. This requires labor and attendant time. Complex flow totalization mechanisms such as the one disclosed in Hembree et al. '451 present maintenance problems. The need to change the filter and/or the filter housing and/or the diverter valve all require labor and attendant time. In each of the foregoing disclosures, the devices disclosed therein are designed for disassembly of some sort as a matter of maintenance of the filtration device. Filtration devices customarily employ replaceable filter cartridges of some type. These arrangements require either a coupling arrangement for attaching and detaching a replacement filter cartridge or a large chamber to entirely enclose the replacement filter cartridge. Both approaches require additional components and materials that add to the manufactured cost and complexity of the device. Furthermore, each of the foregoing disclosures, by requiring the replacement of the filter element, cause great inconvenience to the user by having him search for and procure replacement filter elements at considerable cost. This arrangement, while lucrative for the manufacturer, is a well documented nuisance for the consumer. In addition, most of the devices in the related art, owing to their need for easy access and maintenance are relatively large and obtrusive partially blocking the sink basin. Finally, the devices noted above and most others despite the availability of high capacity filter media are not designed for long life so as to maximize the frequency with which users must purchase replacement filter elements. It is therefore desirable to have a small faucet-mounted water filtration device which is a single-use, long-life water filtration device which includes an indicator of filter performance. By single use it is meant that it is discarded when its performance indicator reveals that the efficacy of the filter has been diminished. It is also desirable to have the filter housing of the water filtration device mounted behind the connection to the faucet to enable full access to the sink basin beneath the faucet.
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<SOH> SUMMARY OF THE INVENTION <EOH>A single-use faucet-mounted water filtration device is provided. The device is of uni-body construction and has no removable or replaceable parts yet provides long life operation. This arrangement makes the device more convenient to use compared with other devices that require frequent replacement of filter cartridges. The device is constructed with a minimum of components making it relatively small in size and less costly to manufacture. While compact, the device is able to hold enough filter media to allow for long life operation. The life of the water filtration device is dependent upon the type of filter media used, sizing and geometry of the filter media, and the sizing and geometry of water flow paths. For instance, water filtration devices having a useful life of 300 gallons or more can be made utilizing the teachings of the instant invention. Water filtration devices having useful lives smaller than 300 gallons may also be made utilizing the teachings of the instant invention. Performance indications as a function of integrated flow are indicated by a light emitting diode. The main housing of the devices resides beneath the faucet neck and rearward of the water discharge point thus not obstructing the sink basin. A single-use device is provided for use in a kitchen sink and a device is provided for use in a bathroom sink. Unlike devices in the related art the bathroom embodiment of the single-use faucet filter is scaled to the small size of bathroom sinks and therefore practical for use in bathrooms. The bathroom filter device allows residential users to have the benefit of filtered water in close proximity to the bedroom avoiding the inconvenience of going to a kitchen sink for water during the night. In addition, because the bathroom device is small and disposable it may be taken with a traveler and installed in a hotel or motel room. Further, as travelers readily discern the differences between water and its tastes from one place to another it is highly desirable that the water filter be portable. The invention includes a front housing connectable to a water faucet and a filter housing having an inlet and an outlet. An end cap of the filter housing completes the filter housing. The front housing is non-removably affixed to the filter housing and the water filter is non-removably contained within the water filter housing. The water filter housing includes a chamber in communication with the water filter. The filter is preferably activated carbon and includes a filter pre-wrap. Other filter media may be used. The outlet resides in the chamber. Alternatively, a second outlet may also reside in the chamber in the embodiment of the bathroom filter. The single use water filtration device is small. The embodiment designed for bathroom use has a filter diameter less than or equal to 1.6 inches. The embodiment designed for kitchen use has a filter diameter less than or equal to 2.2 inches. The water filtration devices disclosed herein, namely the bathroom and kitchen embodiments, reside substantially rearwardly with respect to the water faucet. Other diameters and sizes of the water filtration devices disclosed herein may be made using the teachings hereof. The filter includes ends thereof each secured to an end cap. The end caps have peripheral seal portions which seal against the interior of the filter housing. A housing end cap is ultrasonically welded to the filter housing. Other welding methods such as microwave, radio frequency (RF), heat and induction welding may be employed to weld various portions of the water filtration devices disclosed herein together. The second outlet includes a valve seat and a valve interposed in the filter housing being operable against the valve seat of the second outlet for controlling the flow out of the second outlet. The valve includes a plunger having a foot and an elastomeric ball valve or boot residing over the foot. The foot of the plunger and the elastomeric ball valve reside within the housing. A handle is pivotally connected to the end cap of the filter housing and engages the plunger such that when the plunger is depressed the elastomeric ball valve moves inwardly toward the center of the housing and away from the seat of the second outlet. A fountain head is rotatably secured in the plunger and lever for communication with a passageway in the plunger. A spring is interposed between the plunger and the filter housing urging the elastomeric ball valve against the valve seat of the second outlet. A front housing having first and second passageways is non-removably affixed to the filter housing. The front housing includes a directional valve residing within the front housing and movable therein for directing water into the filter for filtering or through the front housing for direct use of the unfiltered water. The filter housing includes three protrusions which interengage corresponding apertures in the front housing. The front housing also includes a continuous periphery welded to the filter housing by one of the aforementioned methods. The filter housing includes a recess whose shape is the reciprocal of the continuous periphery of the front housing and the continuous periphery of the front housing fits snugly within the recess in the filter housing. The end cap of the filter housing is welded to the filter housing. Three parts or pieces, the filter housing, the front housing and the end cap of the filter housing are welded together to provide a unibody or integral construction. A gate having a magnet affixed therein resides in the chamber and swings between a first position and a second position. Spacers extending from the end cap serve to ensure that the gate remains in alignment with respect to the earth. These spacers also serve to ensure that the filter subassembly remains in proper position. The first end cap of the filter includes a first hinge member and the gate includes a second hinge member which coacts with the first hinge member to enable the gate to swing between first and second positions. A gate position sensor resides in a dry portion of the end cap of the water filter housing and is actuated when the gate swings to the second position and the magnet is in proximity to the sensor. An electronic package and a light emitting diode reside in the dry portion of the end cap of the water filter housing. The electronic package outputs a signal to the light emitting diode which indicates the performance of the water filtration device. The electronic package outputs three discrete signals to the light emitting diode to indicate three performance levels of the filter. A filter performance indicator for use in a water filter which includes a gate having a first magnet affixed thereto and a filter boundary having hinges thereon forming a pivot thereon and a second magnet affixed thereto is also disclosed herein. The gate is pivotally affixed to the hinges and is movable in an arc between a first position when no flow impinges upon the gate and the first and second magnets are coupled together and a second position when flow does impinge upon the gate and the first and second magnets are not coupled together. A filter housing includes a sensor therein for sensing the presence of the gate and the first magnet when the gate is in the second position. The filter performance indicator accurately distinguishes between flow and no flow conditions. The gate includes a conically disposed structure extending from the rear side or end thereof which coacts with a cylindrically extending passageway which extends from the filter boundary. A method of making a water filtration device is also disclosed and comprises the steps of: attaching end caps to the filter; inserting the filter within a filter housing; aligning the filter within the filter housing; inserting a portion of a gate into corresponding receptacles on one end of one of the end caps previously affixed to the filter; inserting a sensor and electronic package into an open end of a filter housing end cap; affixing the filter housing end cap to the filter housing forming a chamber between a closed end of the filter housing end cap and the one end of one of the end caps; and, affixing a front housing to the filter housing. The step of attaching end caps to said filter may be performed with adhesive. And, the steps of affixing the end cap of the filter housing, affixing the filter housing end cap to the filter housing and affixing the front housing to the filter housing may be performed by an ultrasonic welding process or one of the other welding processes identified herein. It is an object of the present invention to provide a water filtration device which is disposable and provides an indication as to when the filter should be disposed. It is a further object of the present invention to provide a water filtration device which is small in size and which resides substantially rearwardly with respect to the faucet to which it is mounted. It is a further object of the present invention to provide a water filtration device which is self-contained and which does not require maintenance and, in fact, which cannot be maintained because the parts thereof are non-removably affixed together or non-removably contained therein. It is an object of the present invention to provide a water filtration device at reasonable cost which is disposable and which is faucet mounted. It is an object of the present invention to provide a water filtration device which includes a swinging gate having a magnet therein which in combination with a sensor and an electronic package provides a visual indication as to the status or performance of the filter. It is an object of the present invention to provide a-water filtration device which includes two filtered outlets. It is an object of the present invention to provide a water filtration device which includes a valved outlet with the valve operated by a lever. It is an object of the present invention to provide a water filtration device which includes an outlet having a rotatably mounted fountain head. It is an object of the present invention to provide a water filtration device which includes a lever actuated fountain. It is an object of the present invention to provide a gate which includes a magnet used to provide positional information about the position of the gate. It is an object of the present invention to provide a reliable gate position sensing system which accurately distinguishes between flow and no flow conditions. These and additional objects will become apparent when reference is made to the Brief Description of the Drawings, Description of the Invention and Claims which follow hereinbelow.
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20040701
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20070807
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20050505
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60170.0
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CECIL, TERRY K
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FAUCET-MOUNTED WATER FILTRATION DEVICE INCLUDING GATE POSITION SENSOR
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
| 2,004
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10,883,318
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ACCEPTED
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Annular or penannular prism
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An annular prism capable of causing light (or other radiation) to either converge or diverge is defined by an annulus of material which is transparent to the light (or other radiation). The annulus tapers radially towards either its outer periphery or its central aperture. If the annulus tapers towards its outer periphery, light converges. If the annulus tapers towards its central aperture, light diverges. The degree of tapering determines the degree of convergence or divergence. A cross section of the annulus formed by a plane containing a principal axis of the annulus viewed on only one side of the principal axis may have a triangular shape. In some embodiments, a segment of the annulus may be missing, resulting in a penannular prism which causes light (or other radiation) to converge or diverge about the principal axis of the incomplete annulus for some angular measure less than 360 degrees.
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1. An annular prism for refracting radiation, comprising: an annulus of material transparent to said radiation, said annulus having a radially directed taper from a first edge of said annulus to a second edge of said annulus, said first edge being defined by one of an outer periphery of said annulus and a central aperture of said annulus, said second edge being defined by the other of said outer periphery of said annulus and said central aperture of said annulus, said radially directed taper being a straight line taper such that a notional radially directed line extending from said first edge to said second edge along a front or rear surface of said annulus is a substantially straight line. 2. The annular prism of claim 1 wherein said first edge is defined by the central aperture of said annulus and said second edge is defined by the outer periphery of said annulus. 3. The annular prism of claim 2 wherein said front surface and said rear surface converge to form said outer periphery. 4. The annular prism of claim 2 further comprising an inner surface which defines an inner circumference of said annulus, said inner surface being coaxial with a principal axis of said annulus. 5. The annular prism of claim 4 wherein a cross section of said annulus, formed by a plane perpendicular to said principal axis and being bounded by a first notional radially directed line extending along said front surface from said first edge to said second edge, a second notional radially directed line extending along said rear surface from said first edge to said second edge, and said inner surface, is triangular. 6. The annular prism of claim 5 wherein said triangular cross section is in the shape of an isosceles triangle. 7. The annular prism of claim 1 wherein said front and rear surfaces are optically finished. 8. The annular prism of claim 1 wherein said first edge is defined by the outer periphery of said annulus and said second edge is defined by the central aperture of said annulus. 9. The annular prism of claim 8 wherein said front surface and said rear surface converge to form an inner circumference of said annulus. 10. The annular prism of claim 8 further comprising a peripheral surface which defines an outer circumference of said annulus, said peripheral surface being coaxial with a principal axis of said annulus. 11. The annular prism of claim 10 wherein a cross section of said annulus, formed by a plane perpendicular to said principal axis and being bounded by a first notional radially directed line extending along said front surface from said first edge to said second edge, a second notional radially directed line extending along said rear surface from said first edge to said second edge, and said peripheral surface, is triangular. 12. The annular prism of claim 11 wherein said triangular cross section is in the shape of an isosceles triangle. 13. A penannular prism for refracting radiation, comprising: an incomplete annulus of material transparent to said radiation, said incomplete annulus having a radially directed taper from a first edge of said incomplete annulus to a second edge of said incomplete annulus, said first edge being defined by one of an outer periphery of said incomplete annulus and a central aperture of said incomplete annulus, said second edge being defined by the other of said outer periphery of said incomplete annulus and said central aperture of said incomplete annulus, said radially directed taper being a straight line taper such that a notional radially directed line extending from said first edge to said second edge along a front or rear surface of said incomplete annulus is a substantially straight line. 14. The penannular prism of claim 13 wherein said first edge is defined by the central aperture of said incomplete annulus and said second edge is defined by the outer periphery of said incomplete annulus. 15. The penannular prism of claim 14 wherein said front surface and said rear surface converge to form said outer periphery. 16. The penannular prism of claim 14 further comprising an inner surface which defines an inner circumference of said incomplete annulus, said inner surface being coaxial with a principal axis of said incomplete annulus. 17. The penannular prism of claim 16 wherein a cross section of said incomplete annulus, formed by a plane perpendicular to said principal axis and being bounded by a first notional radially directed line extending along said front surface from said first edge to said second edge, a second notional radially directed line extending along said rear surface from said first edge to said second edge, and said inner surface, is triangular. 18. The penannular prism of claim 17 wherein said triangular cross section is in the shape of an isosceles triangle. 19. The penannular prism of claim 13 wherein said front and rear surfaces are optically finished. 20. The penannular prism of claim 13 wherein said first edge is defined by the outer periphery of said incomplete annulus and said second edge is defined by the central aperture of said incomplete annulus. 21. The penannular prism of claim 20 wherein said front surface and said rear surface converge to form an inner circumference of said incomplete annulus. 22. The penannular prism of claim 20 further comprising a peripheral surface which defines an outer circumference of said incomplete annulus, said peripheral surface being coaxial with a principal axis of said incomplete annulus. 23. The penannular prism of claim 22 wherein a cross section of said incomplete annulus, formed by a plane perpendicular to said principal axis and being bounded by a first notional radially directed line extending along said front surface from said first edge to said second edge, a second notional radially directed line extending along said rear surface from said first edge to said second edge, and said peripheral surface, is triangular. 24. The penannular prism of claim 23 wherein said triangular cross section is in the shape of an isosceles triangle. 25. Eyeglasses comprising: a lens; and an annular prism attached to said lens, said prism including an annulus of transparent material, said annulus having a radially directed taper from a first edge of said annulus to a second edge of said annulus, said first edge being defined by one of an outer periphery of said annulus and a central aperture of said annulus, said second edge being defined by the other of said outer periphery of said annulus and said central aperture of said annulus, said radially directed taper being a straight line taper such that a notional radially directed line extending from said first edge to said second edge along a front or rear surface of said annulus is a substantially straight line. 26. Eyeglasses comprising: a lens; and a penannular prism attached to said lens, said prism including an incomplete annulus of transparent material, said incomplete annulus having a radially directed taper from a first edge of said incomplete annulus to a second edge of said incomplete annulus, said first edge being defined by one of an outer periphery of said incomplete annulus and a central aperture of said incomplete annulus, said second edge being defined by the other of said outer periphery of said incomplete annulus and said central aperture of said incomplete annulus, said radially directed taper being a straight line taper such that a notional radially directed line extending from said first edge to said second edge along a front or rear surface of said incomplete annulus is a substantially straight line.
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FIELD OF THE INVENTION The present invention relates to lenses and prisms, and more particularly to lenses and prisms capable of converging or diverging light or other forms of radiation. BACKGROUND OF THE INVENTION In the field of optics, the use of lenses is commonplace. As is well known in the art, a lens is a piece of glass, plastic, or other transparent material with opposite surfaces, either or both of which are curved, by means of which light rays are refracted so that they converge or diverge to form an image. The shape of a lens determines whether the lens will cause light travelling parallel to the principal axis of the lens to converge or diverge. More particularly, lenses that are thicker at their center and thinner at their periphery cause light to converge. Such converging lenses are commonly used to correct hyperopia (farsightedness), an abnormal condition of the eye in which vision is better for distant objects than for near objects as a result of improper focusing of the image of a near object behind the retina rather than on it. In contrast, lenses that are thinner at their center and thicker at their periphery, on the other hand, cause light to diverge. Such diverging lenses are commonly used to correct myopia (nearsightedness), a condition in which vision is better for near objects than for distant objects as a result of improper focusing of the image from a distant object in front of the retina rather than on it. Lenses may also be used to converge or diverge forms of radiation other than light. A novel approach towards converging or diverging light or other radiation would be desirable. SUMMARY OF THE INVENTION An annular prism capable of causing light (or other radiation) to either converge or diverge is defined by an annulus of material which is transparent to the light (or other radiation). The annulus tapers radially towards either its outer periphery or its central aperture. If the annulus tapers towards its outer periphery, light converges. If the annulus tapers towards its central aperture, light diverges. The degree of tapering determines the degree of convergence or divergence. A cross section of the annulus formed by a plane containing a principal axis of the annulus viewed on only one side of the principal axis may have a triangular shape. In some embodiments, a segment of the annulus may be missing, resulting in a penannular prism which causes light (or other radiation) to converge or diverge about the principal axis of the incomplete annulus for some angular measure less than 360 degrees. In accordance with an aspect of the present invention there is provided an annular prism for refracting radiation, comprising: an annulus of material transparent to the radiation, the annulus having a radially directed taper from a first edge of the annulus to a second edge of the annulus, the first edge being defined by one of an outer periphery of the annulus and a central aperture of the annulus, the second edge being defined by the other of the outer periphery of the annulus and the central aperture of the annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the annulus is a substantially straight line. In accordance with another aspect of the present invention there is provided a penannular prism for refracting radiation, comprising: an incomplete annulus of material transparent to the radiation, the incomplete annulus having a radially directed taper from a first edge of the incomplete annulus to a second edge of the incomplete annulus, the first edge being defined by one of an outer periphery of the incomplete annulus and a central aperture of the incomplete annulus, the second edge being defined by the other of the outer periphery of the incomplete annulus and the central aperture of the incomplete annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the incomplete annulus is a substantially straight line. In accordance with yet another aspect of the present invention there is provided eyeglasses comprising: a lens; and an annular prism attached to the lens, the prism including an annulus of transparent material, the annulus having a radially directed taper from a first edge of the annulus to a second edge of the annulus, the first edge being defined by one of an outer periphery of the annulus and a central aperture of the annulus, the second edge being defined by the other of the outer periphery of the annulus and the central aperture of the annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the annulus is a substantially straight line. In accordance with still another aspect of the present invention there is provided eyeglasses comprising: a lens; and a penannular prism attached to the lens, the prism including an incomplete annulus of transparent material, the incomplete annulus having a radially directed taper from a first edge of the incomplete annulus to a second edge of the incomplete annulus, the first edge being defined by one of an outer periphery of the incomplete annulus and a central aperture of the incomplete annulus, the second edge being defined by the other of the outer periphery of the incomplete annulus and the central aperture of the incomplete annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the incomplete annulus is a substantially straight line. Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS In the figures which illustrate example embodiments of this invention: FIG. 1 is a perspective view of a first embodiment of an annular prism; FIG. 2 is a side elevation view of the annular prism of FIG. 1; FIG. 3 is a perspective view of a cross section the annular prism of FIG. 1 taken along line 3-3 of FIG. 1; FIG. 4 is a perspective view of a second embodiment of an annular prism; FIG. 5 illustrates a cross section of the annular prism of FIG. 4 taken along line 5-5; FIG. 6 is a perspective view of the cross section of FIG. 5; FIG. 7 illustrates an eye with central field vision loss; FIG. 8 illustrates operation of a converging annular prism to compensate for central field vision loss; FIG. 9 illustrates an eye with peripheral field vision loss; FIG. 10 illustrates operation of a diverging annular prism to compensate for peripheral field vision loss; FIG. 11 illustrates conventional eyeglasses having an annular prism attached to each lens; FIG. 12 illustrates conventional eyeglasses having a penannular prism attached to each lens; and FIG. 13 illustrates a number of exemplary prism cross section shapes in alternative prism embodiments. DETAILED DESCRIPTION Referring to FIGS. 1-3, an annular prism 20 exemplary of a first embodiment of the present invention is illustrated in perspective view, in side elevation view, and in cross sectional perspective respectively. Annular prism 20 is capable of causing light travelling parallel to principal axis 34 (FIG. 2—described below) to converge. Prism 20 may thus be referred to as a “converging annular prism”. As illustrated, annular prism 20 comprises an annulus 36 of transparent material, such as glass or plastic, having a central aperture 30. The annulus 36 has a front surface 22, a rear surface 24, and a cylindrical inner surface 26. As best seen in FIGS. 2 and 3, annulus 36 tapers towards its outer periphery, with the front and rear surfaces 22 and 24 ultimately converging to form the outer circumference 28 of the annulus 36. As shown in FIG. 3, a cross section of the annular prism 20 formed by a plane that contains the principal axis 34 of the annulus 36 yields a pair of triangular sections. Looking at the cross section on only one side of the principal axis 34 (i.e. such that the cross section is bounded by a first notional, radially directed line extending from the annulus' central aperture 30 along front surface 22 to the outer circumference 28, a second notional, radially directed line extending from the annulus' central aperture 30 along the rear surface 24 to the outer circumference 28, and inner surface 26), front surface 22, rear surface 24, and inner surface 26 can be seen to form an isosceles triangle 32. The triangle 32 has two sides of equal length which correspond to the front and rear surfaces 22 and 24 and one dissimilar length side corresponding to inner surface 26. The one dissimilar length side of the triangle 32 is parallel to the principal axis 34 (FIG. 2). The shape of the annular prism 20 matches the three-dimensional volume that would be defined by rotating triangle 32 a full 360 degrees about principal axis 34 (FIG. 2). The inner surface 26 is accordingly coaxial with principal axis 34. The front and rear surfaces 22 and 24 of prism 20 are each optically finished. As known by those skilled in the art, an optically finished surface is one that has been created, cut, ground, or polished to become smooth, with greater smoothness resulting in greater refraction of light or radiation in the desired direction. Inner surface 26 is not necessarily optically finished. The degree of peripheral tapering of the annulus 36 is indicated by the angle θ between the front surface 22 and rear surface 24 (FIG. 3). This angle determines the degree to which light will converge and thus defines the dioptric power of the annular prism 20. A larger angle results in a higher dioptric power. The converging annular prism is annular to avoid undue central prism thickness which would result absent the central aperture in view of the angle θ between the front and rear surfaces of the prism. FIGS. 4-6 illustrate a second annular prism 40 exemplary of a further embodiment of the present invention in perspective view, cross section, and cross sectional perspective respectively. The prism 40 is capable of causing light travelling parallel to the principal axis 54 (FIG. 5) to diverge, and may thus be referred to as a “diverging annular prism”. Diverging annular prism 40 comprises an annulus 56 of transparent material having a central aperture 50. The annulus 40 has a front surface 42, a rear surface 44 and a cylindrical peripheral surface 48. As best seen in FIGS. 5 and 6, the annulus 56 tapers towards its central aperture 50 (i.e. towards the principal axis 54 of the annulus 56). The front and rear surfaces 42 and 44 ultimately converge to form the inner circumference 46 of the annulus 56. As shown in FIG. 5, a cross section of the annular prism 20 formed by a plane that is perpendicular to the principal axis 34 of the annulus 36 yields a pair of triangular sections. Looking at the cross section on only one side of the principal axis 54 (i.e. such that the cross section is bounded by a first notional, radially directed line extending from the annulus' peripheral surface 48 along front surface 42 to central aperture 30, a second notional, radially directed line extending from the annulus' peripheral surface 48 along rear surface 44 to central aperture 30, and peripheral surface 48), the front surface 42, rear surface 44 and peripheral surface 48 can be seen to form an isosceles triangle 52. The triangle 52 has two sides of equal length which correspond to the front and rear surfaces 42 and 44 and a one dissimilar length side corresponding to peripheral surface 48. The one dissimilar length side is parallel to the principal axis 54. The shape of the annular prism 40 matches the three-dimensional volume that would be defined by rotating triangle 52 a full 360 degrees about principal axis 54. The peripheral surface 48 is accordingly coaxial with principal axis 54. The front and rear surfaces 42 and 44 of diverging annular prism 40 are optically finished. The peripheral surface 48 is not necessarily optically finished. The degree of central tapering of the annulus 56 is indicated by the angle e (FIG. 6) between the front surface 42 and rear surface 44. This angle determines the degree to which light will diverge and thus defines the dioptric power of the annular prism 40, with a larger angle resulting in a higher dioptric power. The angle θ is such that convergence of the front an rear surfaces 42 and 44 occurs some radial distance away from the principal axis 54. FIGS. 7-10 illustrate exemplary applications of annular prisms in compensating for certain types of visiori defects. In particular, FIGS. 7 and 8 illustrate use of a converging annular prism 20 to compensate for loss of a central field of vision, and FIGS. 9 and 10 illustrate use of a diverging annular prism 40 to compensate for loss of peripheral fields of vision. Referring first to FIG. 7, an eyeball 64 having central degeneration 70 (e.g. macular degeneration) of retina 74 is illustrated. The eyeball 64 has a lens 66 and together form an optical system with a nodal point 68 so that light from a target object 60 crosses the nodal point 68 and casts an image 71 of the object onto the retina 74. It will be appreciated that nodal point 68 is characteristic to the eyeball 64 and lens 66 and is therefore fixed for a particular shaped of eyeball 64 and lens 66. As a result of the central degeneration 70, the portion of image 71 falling between points A and B on retina 74 is not perceived. Any features of the object 60 in the central area 62, i.e. between points A′ and B′, such as point P for example, are therefore not seen. The portion of the image 71 which falls in area 72, however, which is outside degenerated area 70, can be perceived. The upper and lower parts 61 of the object 60 are therefore visible. It should be appreciated that, although not apparent from the two dimensional illustration of FIG. 7, in which area 72 is shown to be above and below the degenerated area 70, area 72 actually surrounds the degenerated area 70 on the retina. Accordingly, central field vision loss should be understood not to occur only vertically on retina 74, but in all directions on retina 74 (e.g. laterally, diagonally, etc.). FIG. 8 illustrates the use of a converging annular prism 20 to compensate for the central field vision loss illustrated in FIG. 7. Eyeball 64 of FIG. 8 has the same central degeneration 70 between points A and B of retina 74 as in FIG. 7. With annular prism 20 in place in front of eyeball 64, light rays 78 travelling parallel to principal axis 76 of the annulus of prism 20 are refracted by the prism 20 so as to converge towards the principal axis 76. The refracted light then passes through nodal point 68 of the optical system formed by eyeball 64 and lens 66 and results in an image 75 of the object being cast onto retina 74. Because of the refraction performed by the converging annular prism 20, the height of the image 75 that is cast upon the retina 74 is effectively larger than it would be without the prism. As a result, a smaller percentage of the image 75 falls upon the degenerated area 70. Thus, while it is still true that a central part 77 of the object 60 (between A″ and B″) cannot be seen, the unseen part 77 when the annular prism 20 is in place is smaller than the unseen part 62 (FIG. 7) when the prism 20 is absent. Put another way, the upper and lower parts 73 of the object 60 which can be seen now represent a larger percentage of the object. Advantageously, the converging annular prism 20 allows point P of object 60, which was previously unseen, to be perceived, because the image of point P now falls upon functional retina area 72. It should be appreciated that, because refraction by prism 20 occurs 360 degrees around the principal axis 76, image 75 on retina 74 is expanded not only vertically, but also laterally. The size of the inner circumference of the annular prism 20 is selected based on the size of the degenerated area. Referring now to FIG. 9, an eyeball 64 having peripheral degeneration 89 (e.g. retinitis pigmentosa) of retina 74 is illustrated. The eyeball 64 has a lens 66 and together form an optical system with a nodal point 68 so that light from a target object 60 crosses the nodal point 68 and casts an image 91 of the object onto the retina 74. As a result of the peripheral degeneration 89, the portions of image 93 falling above point A and below point B on retina 74 are not perceived. Any features in upper and lower parts 81 of the object 60, i.e. below point A′ and above point B′, such as point P for example, are therefore not seen. The portion of the image 93 which falls in central area 90, however, can be perceived. The central part 82 of the object 60 is therefore visible. FIG. 10 illustrates the use of a diverging annular prism 40 to compensate for the peripheral field vision loss illustrated in FIG. 9. Eyeball 64 of FIG. 10 has the same peripheral degeneration 89 above and below points A and B of retina 74 as in FIG. 9. With annular prism 40 in place in front of eyeball 64, light rays 98 travelling from target object 60 of the annulus of prism 40 are refracted by the prism as shown in FIG. 10. More specifically, light rays 98 entering the prism 40 at angle α1 to the principal axis 96 exit the prism 40 at angle α2 to the principal axis 96, where α2<α1. The refracted light then passes through nodal point 68 of the optical system formed by eyeball 64 and lens 66 and results in an image 95 of the object being cast onto retina 74. Because of the refraction performed by the diverging annular prism 40, the height of the image 95 that is cast upon the retina 74 is effectively smaller than it would be without the prism. As a result, a larger percentage of the image 75 falls upon the functional area 90 of retina 74. Thus, while it is still true that a the upper and lower parts 93 of the object 60 (below A″ and above B″) cannot be seen, the unseen parts 93 when the annular prism 40 is in place are lesser than the unseen parts 81 (FIG. 9) when the prism 40 is absent. Put another way, the central part 92 of the object 60 which can be seen now represents a larger percentage of the object. Advantageously, the diverging annular prism 40 allows point P of object 60, which was previously unseen, to be perceived, because the image of point P now falls upon functional retina area 90. Again, it should be appreciated that, because refraction by prism 40 occurs 360 degrees around the principal axis 96, the size of image 95 on retina 74 is reduced not only vertically, but also laterally. So that it may be used as described above in conjunction with FIGS. 7-10, a converging or diverging annular prism 20 or 40 may be attached to each lens of conventional (or non-corrective) eyeglasses 99 as shown in FIG. 11. Depending upon the type of field loss in each eye, different prisms may be attached to each lens. For example, the degree of tapering of the prisms (i.e. the angle θ) may be different for each prism if the size of the degenerated retinal area in each eye is different. Alternatively, if the field loss is central in one eye and peripheral in the other, one eyeglass lens may have an attached converging annular prism 20 while the other lens has an attached diverging annular prism 40. The characteristics of the prisms to be attached to eyeglass lenses are not dependent on the characteristics of the eyeglass lenses. Not all prisms exemplary of an embodiment of the present invention are necessarily annular. Some prism embodiments may be penannular. A penannular prism is defined by an incomplete annulus, i.e., an annulus with some portion (i.e. a sector) of the annulus being absent. A penannular prism thus spans an angular measure that is less than 360 degrees. For example, a penannular prism may span only 180 degrees, in which case the prism would approximate a “C” shape. Such a penannular prism, when viewed in perspective, would look like the perspective cross section of FIG. 3. This assumes that the prism is a converging penannular prism. A diverging penannular prism spanning 180 degrees would instead look like the perspective cross section shown in FIG. 6. In operation, a penannular prism causes light to converge or diverge, as described above in conjunction with FIGS. 7-10, about the principal axis of the annulus, except that the converging or diverging of light only occurs for the angular measure spanned by the incomplete annulus (less than 360 degrees). For clarity, the “principal axis” of an incomplete annulus is understood to refer to the principal axis of the annulus which would result if the missing portion of the incomplete annulus was in fact present. As shown in FIG. 12, penannular prisms may be affixed to conventional (or non-corrective) eyeglasses 99 in the same manner as annular prisms. Penannular prisms spanning 180 degrees may for example be employed to compensate for hemiopsia, a defect of vision in consequence of which only half of an object is seen. The orientation of the prism on each lens may be different, depending upon the orientation of the degenerated retinal area and field loss of each eye. It will be appreciated that annular or penannular prisms are not necessarily only capable of converging or diverging light. Annular and penannular prisms may also be capable of causing forms of radiation other than light to converge or diverge. Such prisms need only be transparent to the form of radiation that is caused to converge or diverge. For example, charged particles such as electrons may be refracted by an annular or penannular prism comprising a magnetic field. In addition to being suitable for compensating for certain types of vision defects, annular and penannular prisms may also be suitable for various other applications in which light or other radiation is converged or diverged. For example, an annular prism may be used to compact an image viewed under a microscope, so that a larger portion of the image may be seen (albeit at a lesser magnification). As will be appreciated by those skilled in the art, modifications to the above-described embodiment can be made without departing from the essence of the invention. For example, a cross section formed by a plane perpendicular to a principal axis of the annulus, when viewed on only one side of the principal axis (i.e. with the relevant cross section portion being bounded on two sides by a first notional, radially directed line extending along a front surface of the annulus between a first edge defined by the annulus' central aperture and a second edge defined by the outer periphery of the annulus and a second notional, radially directed line extending along the rear surface of the annulus from the first edge to the second edge), may have a shape that is not triangular. The cross section may instead have various other shapes, such as those as shown at 100 in FIG. 13 for example. In each case, the annulus has a radially directed taper, which in the case of a converging prism is directed radially away from the principal axis, and in the case of a diverging prism is directed in the opposite direction. Also in each case, the taper is such that a notional, radially directed line extending along either the front surface or the rear surface of the annulus is a substantially straight line. The same modifications can also be made to penannular prisms. Other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>In the field of optics, the use of lenses is commonplace. As is well known in the art, a lens is a piece of glass, plastic, or other transparent material with opposite surfaces, either or both of which are curved, by means of which light rays are refracted so that they converge or diverge to form an image. The shape of a lens determines whether the lens will cause light travelling parallel to the principal axis of the lens to converge or diverge. More particularly, lenses that are thicker at their center and thinner at their periphery cause light to converge. Such converging lenses are commonly used to correct hyperopia (farsightedness), an abnormal condition of the eye in which vision is better for distant objects than for near objects as a result of improper focusing of the image of a near object behind the retina rather than on it. In contrast, lenses that are thinner at their center and thicker at their periphery, on the other hand, cause light to diverge. Such diverging lenses are commonly used to correct myopia (nearsightedness), a condition in which vision is better for near objects than for distant objects as a result of improper focusing of the image from a distant object in front of the retina rather than on it. Lenses may also be used to converge or diverge forms of radiation other than light. A novel approach towards converging or diverging light or other radiation would be desirable.
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<SOH> SUMMARY OF THE INVENTION <EOH>An annular prism capable of causing light (or other radiation) to either converge or diverge is defined by an annulus of material which is transparent to the light (or other radiation). The annulus tapers radially towards either its outer periphery or its central aperture. If the annulus tapers towards its outer periphery, light converges. If the annulus tapers towards its central aperture, light diverges. The degree of tapering determines the degree of convergence or divergence. A cross section of the annulus formed by a plane containing a principal axis of the annulus viewed on only one side of the principal axis may have a triangular shape. In some embodiments, a segment of the annulus may be missing, resulting in a penannular prism which causes light (or other radiation) to converge or diverge about the principal axis of the incomplete annulus for some angular measure less than 360 degrees. In accordance with an aspect of the present invention there is provided an annular prism for refracting radiation, comprising: an annulus of material transparent to the radiation, the annulus having a radially directed taper from a first edge of the annulus to a second edge of the annulus, the first edge being defined by one of an outer periphery of the annulus and a central aperture of the annulus, the second edge being defined by the other of the outer periphery of the annulus and the central aperture of the annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the annulus is a substantially straight line. In accordance with another aspect of the present invention there is provided a penannular prism for refracting radiation, comprising: an incomplete annulus of material transparent to the radiation, the incomplete annulus having a radially directed taper from a first edge of the incomplete annulus to a second edge of the incomplete annulus, the first edge being defined by one of an outer periphery of the incomplete annulus and a central aperture of the incomplete annulus, the second edge being defined by the other of the outer periphery of the incomplete annulus and the central aperture of the incomplete annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the incomplete annulus is a substantially straight line. In accordance with yet another aspect of the present invention there is provided eyeglasses comprising: a lens; and an annular prism attached to the lens, the prism including an annulus of transparent material, the annulus having a radially directed taper from a first edge of the annulus to a second edge of the annulus, the first edge being defined by one of an outer periphery of the annulus and a central aperture of the annulus, the second edge being defined by the other of the outer periphery of the annulus and the central aperture of the annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the annulus is a substantially straight line. In accordance with still another aspect of the present invention there is provided eyeglasses comprising: a lens; and a penannular prism attached to the lens, the prism including an incomplete annulus of transparent material, the incomplete annulus having a radially directed taper from a first edge of the incomplete annulus to a second edge of the incomplete annulus, the first edge being defined by one of an outer periphery of the incomplete annulus and a central aperture of the incomplete annulus, the second edge being defined by the other of the outer periphery of the incomplete annulus and the central aperture of the incomplete annulus, the radially directed taper being a straight line taper such that a notional radially directed line extending from the first edge to the second edge along a front or rear surface of the incomplete annulus is a substantially straight line. Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
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20040701
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20060926
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20060105
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73318.0
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G02B2500
| 0
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COLLINS, DARRYL J
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ANNULAR OR PENANNULAR PRISM
|
SMALL
| 0
|
ACCEPTED
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G02B
| 2,004
|
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10,883,329
|
ACCEPTED
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Agricultural applicator configuration for enhanced visibility
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A configuration of a three-wheeled agricultural applicator is provided that enhances visibility or the field of view of an operator. The three-wheeled agricultural applicator includes a frame assembly having a fork assembly and a kingpin extending generally upward therefrom. The three-wheeled agricultural applicator further includes a steering assembly that includes a steering wheel interlinked by a left steering actuator and a right steering actuator with a steering plate attached at the top of the kingpin. This configuration allows a hood associated with a drive unit of the three-wheeled agricultural applicator to be angled in a downward direction towards the forward direction of travel, thus enhancing the operator's field of view.
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1. A three-wheeled vehicle, comprising: a drive unit interconnected with a plurality of wheel assemblies in such a manner so as to drive the three-wheeled vehicle in a forward direction of travel, the plurality of wheel assemblies including a single front wheel assembly; a frame assembly mounted on the plurality of wheel assemblies, the frame assembly including a fork assembly and a kingpin extending generally upward therefrom, the fork assembly mounted on the single front wheel assembly; and a steering assembly including a steering wheel interlinked with a steering plate by a left steering cylinder and a right steering cylinder, the steering plate attached at the top of the kingpin extending upward from the fork assembly, wherein rotation of the steering wheel toward a turn direction of the three-wheeled vehicle relative to the forward direction of travel causes the steering plate and attached kingpin and fork assembly to rotate in the turn direction. 2. The three-wheeled vehicle as recited in claim 1, further comprising: a hood having a rearward end and a forward end relative to the forward direction of travel, wherein the hood is angled in a downward direction from the rearward end towards the forward end of the hood and adjacent to the steering plate. 3. The three-wheeled vehicle as recited in claim 2, wherein the hood includes a plurality of louvers, and wherein in the open position of the hood, the louvers are positioned at an angle with respect to horizontal such that the louvers do not obstruct a forward field of view of an operator seated rearward of the hood relative to the forward direction of travel. 4. The three-wheeled vehicle as recited in claim 1, further comprising: a cab supported by the frame assembly, the cab including an operator's station located inside of an enclosure of at least one transparent panel, the operator's station including a seat and a steering console in support of the steering wheel, the operator's station configured to allow an operator to maneuver the three-wheeled vehicle; and a hood mounted forward of the cab, the hood having a rearward end and a forward end relative to the forward direction of travel, the rearward end having a first width and the forward end having a second width, the second width being greater than the first width of the rearward end of the hood, wherein the steering wheel extends upward from the steering console mounted and located inside the cab, the steering console having a top surface, and wherein the rearward end of the hood is generally aligned with a top surface of the steering console. 5. The three-wheeled vehicle of as recited in claim 4, wherein the steering console has a width that is less than the width of the forward end of the hood. 6. The three-wheeled vehicle as recited in claim 4, wherein the cab includes at least one vertical support having an obstructing dimension to a line of sight of the operator seated at the operator's station, and wherein an exhaust outlet associated with the drive unit is located in general alignment with the at least one vertical support such that the exhaust outlet does not additionally obstruct a field of view of the operator seated at the operator's station. 7. The three-wheeled vehicle as recited in claim 4, wherein the enclosure includes: only four vertical supports between a floor support and a ceiling support, the four vertical supports including a first vertical support and a second vertical support located forward of the operator's seat, and a third vertical support and a fourth vertical support located rearward of the operator's seat; and only four transparent panels located between the four vertical supports, the four transparent panels including a first transparent panel pivotally hinged to the first vertical support, and a second transparent panel pivotally hinged to the third vertical support. 8. The three-wheeled vehicle as recited in claim 4, wherein the enclosure of the cab includes a ceiling support and a floor support, wherein the forward transparent panel is curvilinear-shaped and extends downward to the floor support of the cab enclosure. 9. The three-wheeled vehicle of as recited in claim 4, wherein the enclosure of the cab includes a plurality of transparent panels configured to provide an operator with a three hundred-sixty degree field of view from the cab. 10. The three-wheeled vehicle as recited in claim 4, wherein the vehicle includes one or more side-mounted walkways, the walkways located relative to the cab such that walkways do not obstruct a field of view of the operator seated at the operator's station. 11. A three-wheeled agricultural applicator, comprising: a plurality of wheel assemblies including a single front wheel assembly; a frame assembly mounted on the plurality of wheel assemblies, the frame assembly including a fork assembly and a kingpin extending upward therefrom, the fork assembly mounted on the single front wheel assembly; a steering assembly including a steering wheel interlinked with a steering plate by a left steering cylinder and a right steering cylinder, the steering plate attached at the top the kingpin extending from the fork assembly; a cab supported by the frame assembly, the cab including an operator's station located inside of an enclosure of at least one transparent panels, the operator's station including a seat and a steering console configured to allow an operator to operate the agricultural applicator; and a hood mounted forward of the cab relative to the forward direction of travel, the hood having a rearward end and a forward end relative to the forward direction of travel, the rearward end having a first width and the forward end having a second width, the second width being greater than the first width of the rearward end of the hood, wherein the steering wheel extends upward from the steering console mounted and located inside the cab, the steering console having a top surface, and wherein the rearward end of the hood is generally aligned with a top surface of the steering console. 12. The three-wheeled agricultural applicator as recited in claim 11, wherein the cab enclosure includes a ceiling support and a floor support, wherein the at least one transparent panel is curvilinear-shaped and extends downward to the floor support of the cab enclosure. 13. The three-wheeled agricultural applicator as recited in claim 11, wherein the steering console has a width that is less than the width of the forward end of the hood. 14. The three-wheeled agricultural applicator as recited in claim 11, wherein the enclosure includes a plurality of transparent panels configured to provide 360-degree field of view for the operator seated at the operator's station. 15. The three-wheeled agricultural applicator as recited in claim 11, wherein the cab includes at least one vertical support having an obstructing dimension to a line of sight of the operator seated at the operator's station, and wherein an exhaust outlet associated with the drive unit is located in general alignment with the at least one vertical support such that the exhaust outlet does not obstruct a field of view of the operator seated at the operator's station. 16. The three-wheeled agricultural applicator as recited in claim 11, wherein the hood includes a plurality of louvers, the louvers positioned at an angle of about seven degrees with respect to horizontal such that when the hood is in an open position, the louvers do not obstruct a forward field of view of the operator seated at the operator's station. 17. The three-wheeled agricultural applicator as recited in claim 11, wherein the three-wheeled agricultural applicator includes one or more side-mounted walkways, the walkways located relative to the cab such that walkways do not obstruct a field of view of the operator seated at the operator's station. 18. The three-wheeled agricultural applicator as recited in claim 11, wherein the hood slopes in downward direction from the rearward end towards the forward end of the hood. 19. The three-wheeled agricultural applicator as recited in claim 11, wherein the transparent panels are curvilinear-shaped, and wherein the steering console has a width that is less than the width of the forward end of the hood. 20. The three-wheeled agricultural applicator as recited in claim 11, wherein the enclosure of the cab includes: only four vertical supports, the four vertical supports including a first vertical support and a second vertical support located forward of the operator's seat, and a third vertical support and a fourth vertical support located rearward of the operator's seat; and a plurality of transparent panels including a first transparent panel pivotally hinged to the first vertical support, and a second transparent panel pivotally hinged to the third transparent support.
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FIELD OF THE INVENTION The invention relates to a configuration of an agricultural applicator and, more particularly, to a configuration of a three-wheeled agricultural applicator which provides an operator an enhanced field of view. BACKGROUND OF THE INVENTION Numerous types of agricultural applicators or tractors are available today. These can include a pull-type unit or a self-propelled unit. A certain known agricultural applicator is also referred to as a “floater.” The floater is a large vehicle that uses large, oversized floatation tires to carry the vehicle across firm to muddy agricultural environments. A typical floatation chassis assembly includes a pair of rear floatation tires and a front floatation tire. The chassis assembly is configured to support one or more bulk storage tanks or bins of product for application in an agricultural environment, usually before planting in the spring or after harvest in the fall. The types of agricultural products e.g., fertilizer, herbicide, pesticide, nutrients, etc. can vary. The floater can also be utilized to tow various agricultural implements. The oversized-tired agricultural applicators are generally desired for their ability to maneuver heavy loads over extremely rough and difficult agricultural terrain with minimal soil compaction. However, these floater-type agricultural applicators or tractors have drawbacks. Typical three-wheeled floaters include a long and generally horizontally-aligned hood configured in such a manner so as to inhibit the field of view of an operator stationed within the agricultural applicator's cab. For example, U.S. Pat. No. 5,152,364 to Woods et al. discloses a tractor configuration with a long, flat hood extending along a generally horizontal alignment toward a nose. The long, horizontal extending hood inhibits the field of view of an operator stationed with the tractor's cab. Accordingly, there is a desire for a configuration of a three-wheeled vehicle (e.g., floater) that enhances the field of view of an operator stationed with the vehicle's cab. SUMMARY OF THE INVENTION The present invention provides a three-wheeled vehicle configured with an enhanced field of view for an operator. The three-wheeled vehicle includes a frame assembly in support of a drive unit interconnected to drive the frame assembly on three wheel assemblies in a forward direction of travel. One of the three wheel assemblies is a single front wheel assembly. The frame assembly includes a fork assembly and a kingpin extending in a generally upward direction therefrom. The fork assembly is mounted on the single front wheel assembly. The three-wheeled vehicle further includes a steering assembly, the steering assembly generally comprising a steering wheel interlinked with a steering plate by a left steering actuator and a right steering actuator. The steering plate is attached at the top of the kingpin extending upward from the fork assembly. This configuration of the three-wheeled vehicle allows the hood over the drive unit to be sloped downward and adjacent to the steering plate in a manner that enhances a field of view of an operator of the vehicle. The preferred three-wheeled vehicle includes a cab and a hood located forward of the cab relative to the forward direction of travel. The cab, as generally used in conjunction with the agricultural applicator discussed above, includes an operator's station located inside of an enclosure of transparent panels. The operator's station includes a seat and a steering console in support of a steering wheel, and is configured in such a manner for an operator to operate the three-wheeled agricultural applicator. The cab enclosure includes preferably four vertical support members in support of four transparent panels between a floor base and a ceiling support. The four vertical supports generally include a first vertical support and a second vertical support located forward of the operator's seat, and a third vertical support and a fourth vertical support located rearward of the operator's seat. At least one of the four vertical supports has an obstructing dimension to a line of sight of the operator at the operator's station. An exhaust outlet associated with the drive unit is located in general alignment with the at least one vertical support such that the exhaust outlet does not obstruct the field of view of the operator seated at the operator's station within the cab. The four transparent panels are positioned between the four vertical supports. The four transparent panels include a first side transparent panel pivotally hinged to the first vertical support, and a second side transparent panel pivotally hinged to the third vertical support. The first and second side transparent panels are pivotable between a closed position and an open position to provide access to the cab. The four transparent panels further include a third transparent panel located forward of the steering wheel relative to the forward direction of travel, the preferred third transparent panel being preferably curvilinear-shaped and extending downward to the floor base of the cab enclosure. A fourth transparent panel is located rearward and opposite the third transparent panel relative to the forward direction of travel. The four transparent panels are configured to provide a three hundred-sixty degree field of view for the operator within the cab. The preferred hood of the present invention includes a rearward end and a forward end, relative to the forward direction of travel of the agricultural applicator. The rearward end of the hood has a first width and the forward end of the hood has a second width that is greater than the first width of the rearward end of the hood. The rearward end of the hood can be positioned in general alignment with a top surface of the steering console so as to enhance an operator's forward field of view from the cab in a forward direction of travel. It is preferred that the hood be angled in a downward direction from the rearward toward the forward end in the forward direction of travel, such that the forward end of the hood (in a closed position) terminates adjacent to the steering plate of the steering assembly. Furthermore, the hood includes a plurality of louvers positioned at an angle such that, when the hood is in an open position, the louvers do not impede the field of view of the operator stationed within the cab. The present invention thus relates to a configuration of an agricultural applicator and, more particularly, to a configuration of a three-wheeled agricultural applicator, which provides an operator seated at the operator's station within a cab an enhanced field of view not available with other three-wheeled agricultural applicator. Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. BRIEF DESCRIPTION OF THE DRAWINGS Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. FIG. 1 illustrates an isometric view of a three-wheeled agricultural applicator in accordance with the present invention. FIG. 2 illustrates a top view of the three-wheeled agricultural applicator in FIG. 1. FIG. 3 shows a side elevation view of the three-wheeled agricultural applicator shown in FIG. 1. FIG. 4 illustrates a detailed isometric view of the steering assembly of the three-wheeled agricultural applicator in FIG. 1. FIG. 5 illustrates a detailed side elevation view of the cab and the hood of the three-wheeled agricultural applicator in FIG. 1. FIG. 6 is a schematic top view of an operator's station in the cab with respect to an exhaust outlet of the drive unit of the three-wheeled agricultural applicator in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wide variety of vehicles could be constructed in accordance with the invention defined by the claims. Hence, while preferred embodiments of an enclosure in accordance with the invention will now be generally described with reference to a three-wheeled agricultural applicator, it should be understood that the invention is in no way so limited. The type of vehicle configured with enhanced visibility can vary. FIGS. 1 and 2 illustrate an agricultural applicator in accordance with the invention. The preferred agricultural applicator is a conventional agricultural applicator herein referred to as “floater” 20. The floater 20 is a type of agricultural applicator commonly used to apply crop nutrients or animal or human waste (sludge) to soils, typically before planting in the spring and/or after harvest in the fall. The floater 20 generally includes a frame assembly 25 in support of a cab 30, a drive unit 32 (See FIGS. 4 and 5), and one or more bulk storage tanks 35 on a plurality of wheel assemblies 40 and 45. The drive unit 32 enclosed by a hood assembly (discussed later) is generally configured to drive the floater 20 on the plurality of wheel assemblies 40 and 45 in a forward direction of travel (illustrated by arrow 48). The bulk storage tank 35 typically contains agricultural products such as liquid fertilizer or dry fertilizer. The floater 20 can also include a spray distribution assembly (not shown) for application of the stored agricultural product over an agricultural environment. FIGS. 1 and 2 show a preferred embodiment of the floater 20 having a pair of rear wheel assemblies 40 and a single front wheel assembly 45. Although a three-wheeled floater is shown, the number of wheel assemblies 40 and 45 (e.g., a four-wheeled machine, etc.) can vary. Referring to FIGS. 4 and 5, the frame assembly 25 generally includes a front bearing structure 50 (See FIGS. 4 and 5) interlinked with a fork assembly 55. The fork assembly 55 is configured in a known manner to mount on the front wheel assembly 45 (See FIGS. 1 and 2). The fork assembly 55 generally includes a yoke portion 60 that extends between a first fork 65 and a second fork 70. The front wheel assembly 45 (See FIGS. 1 and 2) is mounted between the first and second forks 65 and 70, respectively. Referring to FIG. 5, a kingpin 75 extends upward from the yoke portion 60 and is rotatably mounted to the front bearing structure 50 of the frame assembly 25. Still referring to FIGS. 1 and 2, each of the wheel assemblies 40 and 45 of the floater 20 typically employs over-sized floatation tires 80, which are configured to carry the floater 20 across agricultural terrain (varying from firm to soft, tilled, and sometimes muddy agricultural environments) with minimal soil compaction. The floatation tires 80 of the wheel assemblies 40 and 45 are typically very wide, e.g. forty-three inches. Referring now to FIGS. 1 and 5, the drive unit 32 is positioned between the cab 30 and the forward end 85 of the frame assembly 25 relative to the forward direction of travel 48. The drive unit 32 typically includes an exhaust outlet 90 (e.g. muffler) (See FIG. 1) that extends vertically upward from a laterally off-set position relative to the centrally-positioned drive unit 32 on the frame assembly 25. FIGS. 1, 3, and 6 illustrate a preferred cab 30 in accordance with the present invention. The cab 30 generally includes an enclosure 100 and an operator's station 105 (See FIGS. 3 and 6) located therein. The enclosure generally includes a ceiling support 106 (See FIGS. 1 and 3), a floor base 108 (See FIGS. 1 and 3), a series of vertical supports that includes a first vertical support 110, a second vertical support 112, a third vertical support 114, and a fourth vertical support 116, and a series of transparent panels 120, 122, 124 and 126 mounted therebetween. Referring specifically to FIG. 6, the preferred enclosure 100 includes only four vertical supports 110, 112, 114 and 116 in support of four transparent panels 120, 122, 124 and 126 in order to minimize obstruction to the field of view of the operator at the operator's station in the cab 30. The four transparent panels 120, 122, 124 and 126 are configured to provide an operator in the cab 30 with a three hundred-sixty degree field of view. The four transparent panels 120, 122, 124 and 126 include a first transparent panel 120 that is generally curvilinear-shaped and located between the first and second vertical supports 110 and 112. The preferred enclosure 100 further includes a second transparent panel 122 that is pivotally coupled to the first vertical support 110. A third transparent panel 124 is pivotally coupled to the third vertical support 114. Referring to FIGS. 1 and 3, the preferred series of transparent panels 120, 122, 124 and 126 are of a vertical height that extends from the ceiling support 106 down to the floor base 108 of the enclosure 100. As illustrated in FIG. 6, from a perspective of an operator at the operator's station 105, the first vertical support 110 creates an obstructing dimension that extends generally perpendicular to a line of sight of the operator in the cab 30. The first vertical support 110 is located in general alignment between the operator's station 105 and the exhaust outlet 90 such that the exhaust outlet 90 does not create an additional obstruction beyond the limits of the first vertical support 110, relative to the field of view of the operator at the operator's station 105 within the cab 30. Referring now to FIGS. 3, 5, and 6, the preferred operator's station includes a seat 130 and a steering console 135 with a steering wheel 140 extending therefrom. The steering console 135 and steering wheel 140 are located forward of and in general proximity to the seat 130 so as to allow the operator seated at the operator's station 105 to maneuver the floater 20, relative to the forward direction of travel 48, of the floater 20. Referring to FIGS. 4 and 5, the steering wheel 140 is interlinked with a steering plate 145 attached at the top of the kingpin 75 (See FIG. 5) extending from the fork assembly 55. A left actuator 150 and a right actuator 155, relative to the forward direction of travel 48, are interconnected between the steering wheel 140 and the steering plate 145 in a known manner, such that rotation of the steering wheel 140 causes a respective rotation of the kingpin 75, the fork assembly 55, and mounted front wheel assembly 45 in a direction of a desired turn relative to the forward direction of travel 48. Referring to FIG. 4, the steering plate 145 includes a left coupling 146 and right coupling 148 configured to attach to the left and right steering actuators 150 and 155, respectively. The steering plate 145 is directly attached by a series of fasteners 160 at the top of the kingpin 75 (See FIG. 5). Connecting the left and right steering actuators 150 and 155 directly to the steering plate 145 at the kingpin 75 allows the fork assembly 55 to be shortened. In contrast, the steering actuators of certain known floaters are attached at the fork assembly. Referring to FIGS. 1-3 and 5-6, a hood assembly 170 is configured to enclose the drive unit 32 (See FIG. 5). As illustrated in FIG. 5, the preferred hood assembly 170 includes a hood 175 moveable between a closed position and an open position. Referring now to FIGS. 1-3, the hood 175 includes a rearward end 180 and a forward end 185. As illustrated in particular in FIG. 2, the rearward end 180 of the hood 175 includes a first width 190 and the forward end 185 of the hood 175 includes a second width 195 that is greater than the first width 190 of the rearward end 180 of the hood 175. Referring now to FIGS. 4 and 5, the hood 175 has a low profile because the steering plate 145 is directly attached at the top of the kingpin 75. As illustrated in FIGS. 3 and 5, the low profile of the hood 175 enhances a field of view of the operator at the operator's station 105. Referring in particular to FIG. 3, the hood 175 is angled downward from the rearward end 180 towards the forward end 185 at an angle (θ) with respect to horizontal. The rearward end 180 of the hood 175 is positioned in general alignment with a top surface 200 of the steering console 135 located in the cab 30. As illustrated in FIG. 6, the width 195 of the rearward end 190 of the hood 175 is preferably greater than a width 205 of the steering console 135. This configuration of the hood 175 generally aligns with a line of sight of the operator at the operator's station 105 within the cab 30, thus increasing the operator's field of the view. As illustrated in FIGS. 3 and 6, this low profile configuration of the hood 175 relative to the steering console 135 (i.e., the hood 175 is in general alignment with the top surface 200 of the steering console 135) increases the operator's a field of view when seated at the operator's station 105. In contrast, hoods of known floaters are located at a raised position and are generally horizontally-aligned (i.e., not sloped) because the left and right steering actuators are directly connected at the fork assembly 55, and not to the steering plate 145 as in the present invention. Referring now to FIG. 5, the hood 175 further includes a series of louvers 210. When the hood 175 is in the closed position (shown by solid lines in FIG. 5), the louvers 210 are generally aligned to provide a flow of air through the hood 175 to the drive unit 32. When the hood 175 is in the open position (shown by dashed lines in FIG. 5), the louvers 210 are positioned generally at an angle (φ) with respect to horizontal (e.g., about seven degrees plus or minus two degrees) such that the louvers 210 do not obstruct a forward field of view of the operator seated at the operator's station 105 in the cab 30. The number and size of the louvers 210 can vary. Referring back to FIGS. 1-3, the floater 25 further includes one or more side-mounted storage units 215. The one or more side-mounted storage units 215 may include a handrail 218 mounted thereon. Referring to FIG. 2, a forward portion 220 of the storage units 215 are angled inward (similar on both sides of floater 20) toward the frame assembly 25 at generally the rearward end 180 of the hood 175. Moreover, as shown in FIG. 3, the forward portion 220 of the storage units 215 are also angled downward toward the ground such that the forward and downward field of view of the operator seated at the operator's station 105 is not obstructed by the storage units 215. Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Numerous types of agricultural applicators or tractors are available today. These can include a pull-type unit or a self-propelled unit. A certain known agricultural applicator is also referred to as a “floater.” The floater is a large vehicle that uses large, oversized floatation tires to carry the vehicle across firm to muddy agricultural environments. A typical floatation chassis assembly includes a pair of rear floatation tires and a front floatation tire. The chassis assembly is configured to support one or more bulk storage tanks or bins of product for application in an agricultural environment, usually before planting in the spring or after harvest in the fall. The types of agricultural products e.g., fertilizer, herbicide, pesticide, nutrients, etc. can vary. The floater can also be utilized to tow various agricultural implements. The oversized-tired agricultural applicators are generally desired for their ability to maneuver heavy loads over extremely rough and difficult agricultural terrain with minimal soil compaction. However, these floater-type agricultural applicators or tractors have drawbacks. Typical three-wheeled floaters include a long and generally horizontally-aligned hood configured in such a manner so as to inhibit the field of view of an operator stationed within the agricultural applicator's cab. For example, U.S. Pat. No. 5,152,364 to Woods et al. discloses a tractor configuration with a long, flat hood extending along a generally horizontal alignment toward a nose. The long, horizontal extending hood inhibits the field of view of an operator stationed with the tractor's cab. Accordingly, there is a desire for a configuration of a three-wheeled vehicle (e.g., floater) that enhances the field of view of an operator stationed with the vehicle's cab.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a three-wheeled vehicle configured with an enhanced field of view for an operator. The three-wheeled vehicle includes a frame assembly in support of a drive unit interconnected to drive the frame assembly on three wheel assemblies in a forward direction of travel. One of the three wheel assemblies is a single front wheel assembly. The frame assembly includes a fork assembly and a kingpin extending in a generally upward direction therefrom. The fork assembly is mounted on the single front wheel assembly. The three-wheeled vehicle further includes a steering assembly, the steering assembly generally comprising a steering wheel interlinked with a steering plate by a left steering actuator and a right steering actuator. The steering plate is attached at the top of the kingpin extending upward from the fork assembly. This configuration of the three-wheeled vehicle allows the hood over the drive unit to be sloped downward and adjacent to the steering plate in a manner that enhances a field of view of an operator of the vehicle. The preferred three-wheeled vehicle includes a cab and a hood located forward of the cab relative to the forward direction of travel. The cab, as generally used in conjunction with the agricultural applicator discussed above, includes an operator's station located inside of an enclosure of transparent panels. The operator's station includes a seat and a steering console in support of a steering wheel, and is configured in such a manner for an operator to operate the three-wheeled agricultural applicator. The cab enclosure includes preferably four vertical support members in support of four transparent panels between a floor base and a ceiling support. The four vertical supports generally include a first vertical support and a second vertical support located forward of the operator's seat, and a third vertical support and a fourth vertical support located rearward of the operator's seat. At least one of the four vertical supports has an obstructing dimension to a line of sight of the operator at the operator's station. An exhaust outlet associated with the drive unit is located in general alignment with the at least one vertical support such that the exhaust outlet does not obstruct the field of view of the operator seated at the operator's station within the cab. The four transparent panels are positioned between the four vertical supports. The four transparent panels include a first side transparent panel pivotally hinged to the first vertical support, and a second side transparent panel pivotally hinged to the third vertical support. The first and second side transparent panels are pivotable between a closed position and an open position to provide access to the cab. The four transparent panels further include a third transparent panel located forward of the steering wheel relative to the forward direction of travel, the preferred third transparent panel being preferably curvilinear-shaped and extending downward to the floor base of the cab enclosure. A fourth transparent panel is located rearward and opposite the third transparent panel relative to the forward direction of travel. The four transparent panels are configured to provide a three hundred-sixty degree field of view for the operator within the cab. The preferred hood of the present invention includes a rearward end and a forward end, relative to the forward direction of travel of the agricultural applicator. The rearward end of the hood has a first width and the forward end of the hood has a second width that is greater than the first width of the rearward end of the hood. The rearward end of the hood can be positioned in general alignment with a top surface of the steering console so as to enhance an operator's forward field of view from the cab in a forward direction of travel. It is preferred that the hood be angled in a downward direction from the rearward toward the forward end in the forward direction of travel, such that the forward end of the hood (in a closed position) terminates adjacent to the steering plate of the steering assembly. Furthermore, the hood includes a plurality of louvers positioned at an angle such that, when the hood is in an open position, the louvers do not impede the field of view of the operator stationed within the cab. The present invention thus relates to a configuration of an agricultural applicator and, more particularly, to a configuration of a three-wheeled agricultural applicator, which provides an operator seated at the operator's station within a cab an enhanced field of view not available with other three-wheeled agricultural applicator. Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
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20040701
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20070612
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20060105
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66470.0
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B62D3306
| 0
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ROCCA, JOSEPH M
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AGRICULTURAL APPLICATOR CONFIGURATION FOR ENHANCED VISIBILITY
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UNDISCOUNTED
| 0
|
ACCEPTED
|
B62D
| 2,004
|
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10,883,351
|
ACCEPTED
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Integrated security framework
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A method and apparatus for an integrated security framework. An embodiment of a method comprises identifying network paths for a system; identifying products and platforms for the system; applying application security for the system; analyzing security status for the system; and, based at least in part on the analysis of the security status, automatically identifying changes for the network paths for the system or the products and platforms for the system.
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1. A method comprising: identifying network paths for a system; identifying products and platforms for the system; applying application security for the system; analyzing a security status for the system; and based at least in part on the analysis of the security status, automatically identifying changes for the network paths for the system or the products and platforms for the system. 2. The method of claim 1, further comprising instituting the identified changes. 3. The method of claim 2, wherein the institution of the identified changes is automatic. 4. The method of claim 1, further comprising instituting business practices for the system. 5. The method of claim 4, further comprising automatically identifying business practices for the system based at least in part on the analysis of the security status. 6. The method of claim 5, further comprising providing suggestions to human operators of the system regarding the identified business practices. 7. The method of claim 1, wherein the system is a network. 8. A security system for an enterprise comprising: a component for identifying network paths for the enterprise; a component for identifying products and platforms for the enterprise; and a component for applying application security and analyzing the security status of the enterprise; the component for applying application security and analyzing security status to automatically identify security issues and provide feedback to the component for identifying network paths or the component for identifying products and platforms based at least in part on the identified security issues. 9. The security system of claim 8, wherein security system is to automatically make changes in the component for identifying network paths or the component for identifying products and platforms based at least in part on the identified security issues. 10. The security system of claim 8, further comprising a component for instituting business practices for the enterprise. 11. The security system of claim 10, wherein the security system is to automatically identify business practices based at least in part on the identified security issues. 12. The security system of claim 11, wherein the security system is to automatically notify human operators connected with the enterprise regarding the identified business practices. 13. The security system of claim 8, wherein the enterprise comprises a manufacturing enterprise. 14. The security system of claim 13, wherein the manufacturing enterprise includes semiconductor manufacturing. 15. A manufacturing system comprising; one or more process units, the process units to be accessed by a plurality of users; and a security system for the process units, the security system including: a static security sector, and a dynamic security sector, the dynamic security sector analyzing the status of the security system and providing feedback to the static security sector. 16. The manufacturing system of claim 15, wherein the static security sector comprises a component for identification of network paths, the component for identification of network paths to determine network paths for the plurality of users. 17. The manufacturing system of claim 16, wherein the static security sector further comprises a component for identification of products and platforms, the component for identification of products and platforms to identify products and platforms to be used in connection with access to the system by the plurality of users. 18. The manufacturing system of claim 15, wherein the dynamic security sector comprises a component for applying application security, the component for applying application security to establish application processes for the users with regard to use of the process units. 19. The manufacturing system of claim 15, wherein the security system is to automatically institute changes in the static security sector based at least in part on the analysis of the status of the security system. 20. The manufacturing system of claim 19, wherein the dynamic security sector further comprises a component for business practices. 21. The manufacturing system of claim 20, wherein the dynamic security sector is to automatically identify business practices for the system based at least in part on the analysis of the status of the security system. 22. A machine-readable medium having stored thereon data representing sequences of instructions that, when executed by a processor, cause the processor to perform operations comprising: identifying network paths for a system; identifying products and platforms for the system; applying application security for the system; analyzing a security status for the system; and based at least in part on the analysis of the security status, automatically identifying changes for the network paths for the system or the products and platforms for the system. 23. The medium of claim 22, the instructions further comprise instructions that, when executed by a processor, cause the processor to perform operations comprising instituting the identified changes. 24. The medium of claim 23, wherein the institution of the identified changes is automatic. 25. The medium of claim 22, the instructions further comprise instructions that, when executed by a processor, cause the processor to perform operations comprising instituting business practices for the system. 26. The medium of claim 25, the instructions further comprise instructions that, when executed by a processor, cause the processor to perform operations comprising automatically identifying business practices for the system based at least in part on the analysis of the security status. 27. The medium of claim 26, the instructions further comprise instructions that, when executed by a processor, cause the processor to perform operations comprising providing suggestions to human operators of the system regarding the identified business practices. 28. The medium of claim 22, wherein the system is a network.
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FIELD An embodiment of the invention relates to security systems in general, and more specifically to an integrated security framework. BACKGROUND In all types of system or enterprise operations, security is a major issue that is becoming increasingly important. The introduction of distributed computer access to systems, while providing great benefits, also creates numerous risks. Unauthorized accesses to systems can potentially cause sizeable losses. In one example, semiconductor manufacturing has become more efficient and effective, allowing tools to be remotely access by system users. The remote access is useful to offset the large support costs. However, remote access for semiconductor manufacturing also implies that there are new requirements for security. Conventional systems do provide for security measures in operations such as semiconductor manufacturing, but conventional security does not necessarily provide a solution that responds appropriately to changes. For example, in a conventional system, security often involves network paths (NP), products and platforms (PP), application security (AS), and business process (BP). However, the individual components of security generally do not work together in unison, thus resulting in less than adequate security in a modem environment. BRIEF DESCRIPTION OF THE DRAWINGS The invention may be best understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. In the drawings: FIG. 1 illustrates an embodiment of security elements; FIG. 2 illustrates an embodiment of operation of security elements for a system; FIG. 3 illustrates an embodiment of a computer network including an integrated security framework; FIG. 4 is an illustration of integrated security in a manufacturing environment; FIG. 5 is a flow chart to illustrate an embodiment of security operations for a system; and FIG. 6 is block diagram of an embodiment of a computer system that may be included in an integrated security environment. DETAILED DESCRIPTION A method and apparatus are described for an integrated security framework. According to an embodiment of the invention, an integrated framework provides security for a system or enterprise. Under an embodiment of the invention, a system or enterprise includes semiconductor production systems. A system may include a distributed systems environment of semiconductor process equipment and related shop floor systems. Under an embodiment of the invention, a method for providing security includes four elements or cornerstones of security, such elements being network paths, products and platforms, application security, and business process. Under an embodiment of the invention, a feedback loop is generated to ensure security. In one embodiment, the feedback loop provides for feedback from dynamic security elements to static security elements. The reality of designing and enforcing security is that compromises are inevitable because products and platforms have software defects, and human elements may work against the process. Based on how a system is configured and used, an embodiment of the invention can first determine the overall security of the system. If system security can be improved, improvements can be identified and subsequently implemented. If business needs dictate that a flawed system needs to be used (because, for example, there is no substitute available in the given timeframe) then improvements to business practices may also be identified and implemented to shore up weak security elements. Under an embodiment of the invention, security is required for an integrated system of networks, firewalls, servers, software, and users. In an embodiment, an integrated security system is utilized to identify an appropriate combination of elements to provide security. Under an embodiment of the invention, a security framework includes a static security sector or subsystem and a dynamic security sector or subsystem. In an embodiment, the static security sector comprises identifying exclusive paths and identifying products and platforms. Under an embodiment, dynamic security sector comprises applying application security and the business process. Elements of a security system may be structured as follows: (1) Identifying Exclusive Network Paths—Under an embodiment of the invention, an initial process taken for the purpose of providing security for a system is identification of network paths between users and the system. Networks typically allow connections from multiple resources to multiple destinations. Under an embodiment, a network may be scaleable, possibly without limitation. To secure a system, it is necessary to ensure that only authorized users can access the system and to ensure that all unnecessary accesses to the system are denied. Possible network paths may include the Internet, which implies that network paths may traverse through multiple firewalls and “demilitarized zone” (DMZ) segments. (2) Identifying Products and Platforms—Under an embodiment of the invention, a system includes clients and servers with operating systems, data sources, network connections, firewall rules, and users with varying degrees of authority. Security of a system can be enhanced by ensuring currency of operating systems and providing products with hardening, which are supplemented by secure network configurations such as private VLANs (virtual local area networks), access control lists, firewall rule sets, and other such elements. Selecting the most secure products and platforms practicable, keeping the products and platforms updated, and placing the elements appropriately in the system with exclusive access is fundamental to securing systems. (3) Applying Application Security—If the system was not actually used, then static security elements would be sufficient to protect a system. However, in practice users use applications over a network to create, access, modify, and transform information. Under an embodiment, security needs of operational systems are augmented by a dynamic security element. Application security is truly dynamic, existing for as long as user sessions are active. Applying application security addresses the authenticity of users, provides users with a list of applications users are authorized to use and the approval required for the given task at hand. Application security also facilitates the need to access data in addition to the confidentiality and message integrity requirements based on the security classification of data; and other related concerns. Under an embodiment of the invention, applying application security also comprises inactivity timeouts, reconnections to a system, and proper usage of temporary data stores. Further, choices of network protocols, encryption and message integrity algorithms, and strength and location of processes (such as application layer security versus network layer security) are also important elements. Logging operations (to record or log system activity) are widely accepted as important enablers of audits and security incident tracking (such as computer forensics). Under an embodiment of the invention, if the overall system security status is not deemed sufficient at the end of application security with the cumulative effect of the first three elements (identifying exclusive network paths, identifying products and platforms, and applying application security), then system design and operation enters an iterative process to feedback security issues and reformulate security requirements. The outcome of a determination of inadequate security may result in varying responses, depending on the severity of the security lapses and the particular embodiment. In one embodiment, severe security issues may result in a choice of alternative set of products and platforms (such as operating systems, software products or network connection types), which may require termination of operation for the purpose of installation. In another embodiment, network paths may be adjusted or “tweaked” to secure weaker products or platforms, thereby adding “defense-in-depth” through certain stronger requirements. In one example, a question of security of a connection may result in an additional requirement for encryption of data. Under an embodiment of the invention, a system may automatically impose certain security changes in the iterative process. (4) Business Process—If the application security is adequate, then business practices may follow. Because human lapses are most often the weakest link in a chain of security, several categories of business processes may be required to reinforce security. For example, the registration process for user credentials my require audits to ensure that high ethical standards are followed. Complementary check-ups of the authorization systems may reveal what actions users are not supposed to take and should be prevented from taking, but that can taken in reality. Frequent audits of computer and network configurations are required to ensure conformance to network and system security policies. Further data classification is a dynamic process and the mapping of data to access control has to be evaluated constantly. Business is ever changing with people, roles, functions, tasks, and other issues, thereby requiring that security operations be constantly alert and responsive. Under an embodiment of the invention, security weaknesses of various components of a system are constantly evaluated, with focus being provided on attainment of overall system security via application and system use-cases. Under an embodiment of the invention, iterative evaluation of a security system can be used as a tool during testing and evaluation of security processes and products. The iterative process allows comprehension of how the system responds to security changes, thereby providing a valuable tool to analyze security-related system changes. Under an embodiment of the invention, the iterative process of a security system may also provide notices and alarms to system attendants regarding required changes in business practices. In an embodiment, if an evaluation determines that the system requires additional security, in addition to any other actions taken, the system may provide instructions or suggestions for human operators regarding modifications of or additions to security-related business practices. For example, a system may inform human operators regarding questionable operations, and thereby, indicating the need for audits of certain system sectors are needed, that certain types of access requests should be scrutinized, or that certain users should lose or have reduced access privileges. Under an embodiment of the invention, a system automatically provides instructions to human operators regarding needed changes in business practices to shore up security concerns. Under an embodiment of the invention, an integrated security framework is implemented to attempt to fully provide comprehensive cyber security. Under an embodiment of the invention, a security system is intended to address the entire system and provide global and integrated solutions, rather than being limited to individual elements of security, and piecemeal or point-wise security solutions. FIG. 1 illustrates an embodiment of security elements. In this embodiment, a security framework 100 includes at least four elements, such elements being network paths 105, products and platforms 110, application security 115, and business processes 120. In an embodiment of the invention, establishment of the network paths 105 and the products and platforms form the initial static security elements. In an embodiment of the invention, application security 115 and business practices 120 form the dynamic elements of security. In an embodiment of the invention, the security framework 100 provides for evaluation of security processes. In an embodiment, the security framework 100 includes feedback to the static security elements. FIG. 2 illustrates an embodiment of operation of security elements for a system. In this illustration, the flow of operations in an dynamic security environment are shown. A security process may include static security elements 220 and dynamic security elements 225. In an embodiment, the static security elements 220 comprise identifying exclusive network paths 205 and the products and platforms 210. In an embodiment, the dynamic security elements 215 comprise applying application security 215 and institution of business processes 220. Under an embodiment, the establishment of security system for a system may commence with identification of exclusive network paths 205. In this element, there are determinations regarding what networks paths are to be used for a system. In one example, the network paths element 205 may include a determination regarding what paths a particular user should or should not use in accessing a particular piece of equipment. The establishment of a security system may continue with identifying products and platforms for the system 210. Included in such element is determination whether the products and platforms are up-to-date and are appropriate for the security needs of the system. Upon initial completion of the static security element 220, the framework provides for applying application security 215. There is then a determination whether security is adequate. If security changes are needed in the static security elements 220, the feedback mechanism 230 is used to effect the needed changes. Under an embodiment, the feedback 230 includes automatic modifications in the static security elements 220. Following the application security 215, there is the institution of business practices 220, which is largely a human element. In an embodiment, the process of applying application security 215 may include a feed forward mechanism 235 that provides data from the first three security components regarding business processes 220. Under an embodiment, the feed forward mechanism 235 for business processes includes automatic recommendations to human operators regarding business practices that should be implemented to shore up security for the system. With the implementation of the security elements, the intended result is a secure environment 240. FIG. 3 illustrates an embodiment of a computer network including an integrated security framework. Under an embodiment of the invention, the network includes an integrated security framework. Networks may be comprised of widely varying components, with FIG. 3 providing one simplified example. Networks may be classified according to their geographical area, such as a local area network (LAN), metropolitan area network (MAN), or wide area network (WAN). In its simplest form, a network comprises two or more computers and associated devices that are linked together with some version of communications equipment. Network connections may be established using varying technologies, including twisted-pair wiring, coaxial cable, fiber-optic cable, and radio signals, and may utilize various connectors or devices such as NICs (network interface cards). In this illustration, a network 300 may include one or more hubs, hubs being common connection points for devices in a network. In this illustration, a hub 305 is connected to one or more servers, shown as server 1 310 and server 2 315. (Certain network topologies do not include a designated server.) In addition, a hub 320 is connected to multiple workstations, shown as workstation 1 325, workstation 2 330, and workstation 3 335. The network 300 may also include one or more routers, such as router 340. Routers are devices to forward packets of data, such as in a connection between two networks. In FIG. 3, hub 305 and hub 320 are connected with the router 340. In this illustration, the router 340 also connects the network 300 with the Internet 350, although the connection could be to any other network. The network 300 may include various security devices, including a firewall 345 to protect the network from intrusion. In general, a firewall is hardware, software, and/or procedures intended to prevent unauthorized access to or operation on a network. In FIG. 3, a client 355 may access the network 300 through the Internet 350. Under an embodiment of the invention, the network 300 includes an integrated security framework 360. In an embodiment, the security framework 360 includes a static security sector 365 and a dynamic security sector 370. In an embodiment, the security framework 360 may include processes for establishing security for the access of the client 355 to the network 300. Under an embodiment, the static security sector 365 is established for the network 300. Under an embodiment, the dynamic security sector 370 is then established. The dynamic security 370 also analyzes the security status of the network 300 and provides feedback regarding the static security sector 365 based at least in part on the analysis. FIG. 4 is an illustration of integrated security in a manufacturing environment. In this illustration, a manufacturing system 400 may include the manufacturing of semiconductors. The manufacturing system 400 may include multiple process units, including a unit 1 405, a unit 2 410, and a unit 3 415. Users of the process units may include both remote users 445, shown as accessing the manufacturing system 400 through the Internet 440, and local users 455, shown as accessing the manufacturing system 400 through a local intranet 450. Under an embodiment of the invention, the establishment of security for the manufacturing system 400 includes identifying network paths for the system. In this simplified illustration, multiple paths may be followed to reach the process units. For example, unit 1 405 may be reached via a first node 420 (representing a switch, router, hub, or other such device), or via the first node to a second node 425. The security process may include identifying which network paths will be used for process units. Under an embodiment of the invention, the establishment of security for the manufacturing system 400 further includes identifying products and platforms for the manufacturing system 400. For example, the products may include firewalls for security, shown as a firewall 430 for access from the Internet 440, which then connects to the local intranet 450. Under an embodiment of the invention, the establishment of security for the manufacturing system 400 includes identifying establishing application security for the manufacturing system 400. Under an embodiment, the establishment of security further includes analyzing the security status of the manufacturing system 400 and providing feedback for improvements in security. For example, if modifications in usage or network paths change security concerns, the feedback may be provided regarding the network paths and the products and platforms. In an embodiment of the invention, the establishment of security includes automatically identifying changes to the network paths and the products and platforms for the manufacturing system 400. In an embodiment of the invention, the establishment of security further includes automatically implementing identified changes to the network paths and the products and platforms for the manufacturing system 400. Under an embodiment of the invention, the establishment of security for the manufacturing system 400 includes establishing business practices, which may have great impact on overall security. In an embodiment of the invention, the establishment of security includes automatically identifying changes to the business practices to improve security for the manufacturing system 400. In an embodiment of the invention, the establishment of security further includes automatically providing notice to human operators of the manufacturing system 400 regarding suggested changes in business practices. FIG. 5 is a flow chart to illustrate an embodiment of security operations for a system. In this illustration, there is an identification of network paths for a system 505. There is also identification of products and platforms to be used with the system 510. The network paths and the products and platforms are “static” elements of the security for the system. These elements are then followed by the installation of application security in connection with operation of the system 515. With the initial security in place, there is an evaluation of the status of security for the system 520. Under an embodiment of the invention, if the evaluation of the status of security for the system indicates that there are issues regarding static security 525, automatic directives for changes in static security, based at least in part on the analysis, are generated 530 and the system feed back to the static security elements. This process may be an iterative operation to continue making adjustments until the system is sufficiently secure. Under an embodiment of the invention, if the evaluation of the status of security for the system indicates that there are issues regarding business practices 535, automatic instructions to human operators regarding business practices are generated 540. The business practices for the system are then instituted 545. FIG. 6 is block diagram of an embodiment of a computer system that may be included in an integrated security environment. Under an embodiment of the invention, a computer 600 comprises a bus 605 or other communication means for communicating information, and a processing means such as two or more processors 610 (shown as a first processor 615 and a second processor 620) coupled with the first bus 605 for processing information. The processors may comprise one or more physical processors and one or more logical processors. The computer 600 further comprises a random access memory (RAM) or other dynamic storage device as a main memory 635 for storing information and instructions to be executed by the processors 610. Main memory 635 also may be used for storing temporary variables or other intermediate information during execution of instructions by the processors 610. The computer 600 also may comprise a read only memory (ROM) 640 and/or other static storage device for storing static information and instructions for the processor 610. A data storage device 645 may also be coupled to the bus 605 of the computer 600 for storing information and instructions. The data storage device 645 may include a magnetic disk or optical disc and its corresponding drive, flash memory or other nonvolatile memory, or other memory device. Such elements may be combined together or may be separate components, and utilize parts of other elements of the computer 600. The computer 600 may also be coupled via the bus 605 to a display device 655, such as a cathode ray tube (CRT) display, a liquid crystal display (LCD), or other display technology, for displaying information to an end user. In some environments, the display device may be a touch-screen that is also utilized as at least a part of an input device. In some environments, display device 655 may be or may include an auditory device, such as a speaker for providing auditory information. An input device 660 may be coupled to the bus 605 for communicating information and/or command selections to the processors 610. In various implementations, input device 660 may be a keyboard, a keypad, a touch-screen and stylus, a voice-activated system, or other input device, or combinations of such devices. Another type of user input device that may be included is a cursor control device 665, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to the one or more processors 610 and for controlling cursor movement on the display device 665. A communication device 670 may also be coupled to the bus 605. Depending upon the particular implementation, the communication device 670 may include a transceiver, a wireless modem, a network interface card, or other interface device. The computer 600 may be linked to a network or to other devices using the communication device 670, which may include links to the Internet, a local area network, or another environment. The computer 600 may also comprise a power device or system 675, which may comprise a power supply, a battery, a solar cell, a fuel cell, or other system or device for providing or generating power. The power provided by the power device or system 675 may be distributed as required to elements of the computer 600. In the description above, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form. The present invention may include various processes. The processes of the present invention may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor or logic circuits programmed with the instructions to perform the processes. Alternatively, the processes may be performed by a combination of hardware and software. Portions of the present invention may be provided as a computer program product, which may include a machine-readable medium having stored thereon instructions, which may be used to program a computer (or other electronic devices) to perform a process according to the present invention. The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, CD-ROMs (compact disk read-only memory), and magneto-optical disks, ROMs (read-only memory), RAMs (random access memory), EPROMs (erasable programmable read-only memory), EEPROMs (electrically-erasable programmable read-only memory), magnet or optical cards, flash memory, or other type of media/machine-readable medium suitable for storing electronic instructions. Moreover, the present invention may also be downloaded as a computer program product, wherein the program may be transferred from a remote computer to a requesting computer by way of data signals embodied in a carrier wave or other propagation medium via a communication link (e.g., a modem or network connection). Many of the methods are described in their most basic form, but processes can be added to or deleted from any of the methods and information can be added or subtracted from any of the described messages without departing from the basic scope of the present invention. It will be apparent to those skilled in the art that many further modifications and adaptations can be made. The particular embodiments are not provided to limit the invention but to illustrate it. The scope of the present invention is not to be determined by the specific examples provided above but only by the claims below. It should also be appreciated that reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature may be included in the practice of the invention. Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims are hereby expressly incorporated into this description, with each claim standing on its own as a separate embodiment of this invention.
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<SOH> BACKGROUND <EOH>In all types of system or enterprise operations, security is a major issue that is becoming increasingly important. The introduction of distributed computer access to systems, while providing great benefits, also creates numerous risks. Unauthorized accesses to systems can potentially cause sizeable losses. In one example, semiconductor manufacturing has become more efficient and effective, allowing tools to be remotely access by system users. The remote access is useful to offset the large support costs. However, remote access for semiconductor manufacturing also implies that there are new requirements for security. Conventional systems do provide for security measures in operations such as semiconductor manufacturing, but conventional security does not necessarily provide a solution that responds appropriately to changes. For example, in a conventional system, security often involves network paths (NP), products and platforms (PP), application security (AS), and business process (BP). However, the individual components of security generally do not work together in unison, thus resulting in less than adequate security in a modem environment.
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<SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>The invention may be best understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. In the drawings: FIG. 1 illustrates an embodiment of security elements; FIG. 2 illustrates an embodiment of operation of security elements for a system; FIG. 3 illustrates an embodiment of a computer network including an integrated security framework; FIG. 4 is an illustration of integrated security in a manufacturing environment; FIG. 5 is a flow chart to illustrate an embodiment of security operations for a system; and FIG. 6 is block diagram of an embodiment of a computer system that may be included in an integrated security environment. detailed-description description="Detailed Description" end="lead"?
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20040630
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20090512
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20060126
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94363.0
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G06F1214
| 0
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COULTER, KENNETH R
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INTEGRATED SECURITY FRAMEWORK
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UNDISCOUNTED
| 0
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ACCEPTED
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G06F
| 2,004
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10,883,537
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ACCEPTED
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Electronic device display system and method
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A system and method are provided for displaying electronic devices operable when electrical power is supplied to them at respective operating voltages through respective power connectors. The system has a power supply providing input electrical current at a first voltage and cable structures each connected with the power supply and having a respective power connector electrically connecting with the power receiving structure of one of the electronic devices. The cable structures each include a voltage regulator system that receives the input electrical current, converts it to an output electrical current at an output voltage, and transmits it to the power connector, so as to transmit an operating electrical current to the associated electronic device. The voltage regulator system sets the output voltage of the output electrical current such that the operating electrical current delivered to the associated electronic device has a voltage that corresponds to the operating voltage of that device. This is accomplished by connecting the voltage regulator to a calibrating component with a selected electrical characteristic that sets the output voltage. A security circuit creates an alarm when separation of the electrical device from the system occurs.
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1. A system for displaying a plurality of electronic devices each being operable when electrical power is supplied thereto at a respective operating voltage through a respective power connector, said system comprising: a power supply providing input electrical current at a first voltage; a plurality of cable structures each being connected with the power supply so as to receive said input electrical current therefrom at said first voltage, and each having a respective power connector configured to electrically connect with the power receiving structure of a respective one of the electronic devices; said cable structures each including a respective voltage regulator system receiving said input electrical current, and converting said input electrical current to a respective output electrical current at a respective output voltage and transmitting said output electrical current to said power connector so as to transmit an operating electrical current to the associated electronic device; said voltage regulator system setting the output voltage of the output electrical current such that the operating electrical current delivered to the associated electronic device has a voltage that corresponds to the operating voltage of said electronic device. 2. The system of claim 1, wherein the voltage regulator system comprises a voltage regulator electrically connected with a calibrating component, said voltage regulator setting the output voltage of said output electrical current dependent upon an electrical characteristic of said calibrating component. 3. The system of claim 2, wherein the electrical characteristic of the calibrating component on which the output voltage of the output current depends is resistance, and said calibrating component comprises a resistor. 4. The system of claim 2, wherein the calibrating component is electrically connected with the voltage regulator via a releasable connector structure. 5. The system of claim 4, wherein the releasable connector structure is a jack-and-socket system. 6. The system of claim 4, wherein said releasable connector structure also connects said voltage regulator system with the power connector. 7. The system of claim 6, wherein the releasable connector structure is a jack-and-socket electrical connection system comprising a socket connected with the voltage regulator, and a jack connected to an end of a cable having an opposite end connected electrically with said power connector so that said output current from said voltage regulator flows to said power connector through said cable. 8. The system of claim 7, wherein said calibrating component is also connected with said opposite end of said cable. 9. The system of claim 8, wherein the power connector has a body and the calibrating component is supported in or adjacent said body. 10. The system of claim 7, wherein the jack has a body, and the calibrating component is in said body. 11. The system of claim 10, wherein said jack and socket system is a USB plug structure. 12. The system of claim 7, wherein the cable has at least four conductor wires therein, two of said wires being operatively connected with the power conductor so as to power the device, and another two of the wires being electrically connected with said calibrating component so as to form a circuit therethrough. 13. The system according to claim 1, wherein the power supply is part of a base module from which the cable structure extends; said cable structure including a security module configured to be secured to the associated electronic device; said cable structure including a cable portion forming a security circuit extending from the base module to said security module; said security module closing the security circuit when said security portion is secured to the electronic device, and said security module breaking the security circuit when the security module is removed from the electronic device, and an alarm system determining if the security circuit has been broken, said alarm system generating a visible or audible alarm responsive to a determination that the security circuit has been broken. 14. The system of claim 13, wherein the alarm is in the security module. 15. The system of claim 14, wherein the voltage regulator system is supported on the security module, and the cable portion of security circuit extends between the base module and the security module as part of a cable that also conducts the input electrical current to the voltage regulator system. 16. The system of claim 13, wherein the alarm is in the base module. 17. A system for displaying a plurality of electrical devices each operable by a user when electrical power is supplied thereto at a respective operating voltage via a respective power receiving structure thereof that is configured to electrically connect with a complementary power supply connector, said system comprising: a base module having a power supply providing DC current at a first voltage to a plurality of electrical connector structures; a plurality of a cable assemblies each being associated with a respective one of the electrical devices and comprising: a first cable having first and second ends, the first end being electrically connected with a respective electrical connector structure of the base module and receiving said DC current therefrom at said first voltage; a device module electrically connected with the second end of the first cable and secured to said electrical device; the device module having a voltage regulator receiving the DC current, converting said DC current to an output current at an output voltage, and transmitting said output voltage to a device module output connector structure; a first connector structure connected with the device module output connector structure and receiving said output current therefrom; a second cable having first and second ends, said first end being electrically connected with the first connector structure so that said output current is transmitted through the second cable; a power connector on the second end of the second cable, said power connector complementarily engaging with the power receiving structure of said electrical device and transmitting said output current to the power receiving structure of said electrical device; a calibrating component connected with the first connector structure and electrically connected therethrough with the voltage regulator; the voltage regulator being configured such that the output voltage of the output current therefrom is dependent on an electrical characteristic of the calibrating component connected therewith; said calibrating component being selected to set the output voltage of the output current of the voltage regulator such that the output current transmitted to the power receiving structure of said electrical device is at the operating voltage of said electrical device. 18. The system of claim 17, wherein the first cable includes a security circuit comprising at least one wire extending from the base module to the device module, said security circuit being closed when the said cable structure is assembled and the device module is secured to the electrical device, said security circuit remaining closed during normal operation of the system; sensing circuitry determining if said security circuit has been interrupted; and an alarm system connected with the sensing circuitry and generating an audible or visible alarm responsive to a determination by the sensing circuitry that the security circuit has been interrupted. 19. The system of claim 18, wherein the device module includes a securement structure securing the device module to the electrical device; the security circuit including an element that breaks the security circuit when the securement structure releases the device module from the electrical device, triggering said alarm. 20. The system of claim 17 wherein the electrical characteristic is resistance, and said calibrating component comprises a resistor. 21. The system of claim 17 wherein the first connector structure has at least four electrical contacts, two of said electrical contacts connecting with the calibrating component and another two of said electrical contacts connecting with the power connector. 22. The system of claim 17, wherein the first connector structure is a jack plugged into the device module output connector structure, said jack having a body, and said calibrating component being supported in the body of the jack. 23. The system of claim 22, wherein the jack is a USB connector and the output connector structure is a USB socket. 24. The system of claim 17, wherein said electrical connector structures of the base module are each sockets having electrical contacts; the first end of the first cable including a jack configured to be matingly received in the respective socket of the base module, said first cable having lines therein electrically connecting through said jack to respective contacts in the socket; the second end of the first cable connecting with the device module by a jack-and-socket system. 25. The system of claim 24, wherein at least one line of the first cable carries said DC current to the device module; and wherein at least one other line of the first cable forms a closed security circuit when the first cable is plugged into the base module socket and the jack and socket system of the device module and the device module is secured to the electronic device; an alarm system continually or periodically determining whether the security circuit is closed, said alarm system generating a visible or audible alarm responsive to a determination that the security circuit is not closed. 26. A method for displaying a plurality of electrical devices each being supplied with electrical current at a respective operating voltage through a respective power input structure configured to electrically connect with a respective power connector structure fitting complementarily therewith, said method comprising: providing a base module having a power supply with a plurality of electrical connector structures each supplied with DC current at a first voltage; securing to each electronic device a respective device module; connecting a first cable between each device module and a respective electrical connector structure of the base module so that said first cables each carry said DC current at said first voltage to the associated device module; the device modules each having a respective voltage regulator receiving the DC current and converting said DC current to a respective output current; connecting a second cable between each device module and the electrical device secured thereto, said second cable receiving the output current from the device module and transmitting the output current to a power connector complementarily engaging and electrically connecting with the power input structure of said electrical device; said output current being transmitted to the electrical device at a voltage corresponding to the operating voltage of said device; each of said voltage regulators setting the associated output current at a voltage that is dependent on an electrical characteristic of a respective calibrating component connected therewith, said calibrating component being part of the associated second cable connected with the device module. 27. The method of claim 26, wherein said first cables each form a respective security circuit linking the base module and the associated device module, said security circuit being closed when said device module is second to the associated electrical device; said method further comprising: detecting that the security circuit is closed after securement of the device module to the electronic device and connection of the first cable between the base module and the device module and initiating an alarm-set condition responsive to said determination; detecting continuously or periodically during the alarm-set condition whether the security circuit remains closed, and responsive to a detection that the security circuit has been broken during the alarm-set condition, generating an alarm condition that includes activating a visible or audible alarm. 28. The method of claim 27, wherein said securing of the device module to said electronic device including applying a securement system that, when applied, closes a switch in the security circuit, and, when released, opens said switch so as to break the security circuit. 29. The method of claim 26, wherein the first cables each have two ends with modular jack structures, said electrical connector structures each being a socket receiving a respective jack structure at one end of the first cable, and said device modules each having an input socket receiving the respective jack structure at the other end of said first cable. 30. The method of claim 29, wherein said first cables comprise modular ethernet cables. 31. The method of claim 26, wherein the device modules each have a respective jack-and-socket structure modularly connecting with the associated second cable. 32. The method of claim 27 and further comprising: illuminating at least one indicator light responsive to the initiation of the alarm-set condition. 33. A cable assembly comprising: a first electrical connector element having at least four electrical contacts configured to make four separate electrical connections when said first electrical connector element is secured in engagement with a complementary electrical connector structure; a cable portion having two opposite ends and two wires each connected with a respective one of said electrical contacts of the first electrical connector element; a device power input jack having at least two electrical contacts each connected electrically with a respective wire of said cable portion, said power input jack being configured to be matingly engaged with a power input structure as an electrical device so as to form an electrical connection therewith supplying electrical power to said electrical device at an operating voltage through said power input structure; a calibrating component connected with two other contacts of the first electrical connector element so that a circuit containing the calibrating component is formed between said two contacts, said calibrating component having an electrical characteristic selected to cause a voltage regulator connected therewith to transmit electrical power at a voltage corresponding to the operating voltage of the electrical device. 34. The cable assembly of claim 33, wherein said first electrical connector is a jack element configured to be inserted in a complementary socket. 35. The cable assembly of claim 33, wherein the first electrical connector element has a body and the calibrating component is supported therein. 36. The cable assembly of claim 33, wherein the electrical characteristic is resistance, and the calibrating component comprises a resistor. 37. The cable assembly of claim 33, wherein the cable portion has at least four wires, and the calibrating component is supported in or adjacent the power input jack, two of said wires of the cable portion being electrically connected with the calibrating component. 38. A module for use in a system for display of an electrical device having an operating voltage, said module comprising: a housing including a securement structure configured to secure said module to said electrical device; a power input supported on said module and configured to be connected with a power input cable so as to receive therefrom an electrical current having an input voltage; a voltage regulator supported in said housing and having an input and an output, said input being electrically connected with the power input so as to receive said electrical current therefrom; said voltage regulator being configured to convert said electrical current to an output current at an output voltage and to transmit the output current through the output; the voltage regulator having a calibrating input, said voltage regulator being configured to set the output voltage of the output current dependent on an electrical characteristic of a calibrating component connected electrically with said calibrating input; a connector structure electrically connected with the calibrating input of the voltage regulator, said connector structure being configured to releasably connect with a complementary connection structure so that a user can selectively connect to said voltage regulator a calibrating element having an electrical characteristic to cause said voltage regulator to set the output voltage to an appropriate voltage in view of the operating voltage of the electrical device. 39. The module of claim 38, wherein the electrical characteristic on which the output voltage depends is resistance. 40. The module of claim 38, wherein said output current is transmitted to said connector structure, said connector structure having contacts for connection with the calibrating element and other contacts for transmission of the output current to the electrical device. 41. The module of claim 38, wherein the connector structure is a socket configured to receive a jack and electrically connect therewith. 42. The module of claim 41, wherein the socket is a USB socket. 43. The module of claim 38, wherein the module has a security circuit portion connected with the power input, said security circuit portion being closed when the module is secured in engagement with the electrical device. 44. The module of claim 43, wherein the security circuit portion includes a securement assembly having a securing mechanism securing the module to the electrical device, said securement assembly including a switch that is closed when the module is secured to the electrical device by the securing mechanism, said switch opening so as to break the security circuit portion when said securing mechanism is made to release the electrical device. 45. The module of claim 44, wherein the input is an electrical connector structure having at least three contacts, one of said contacts receiving the electrical current, and the two other contacts constituting two ends of the security circuit portion. 46. The module of claim 45, wherein said electrical connector structure is a socket configured to receive and electrically connect with a jack on an end of said power input cable. 47. The module of claim 44, wherein the securement mechanism includes a screw assembly that is configured to screw into a threaded aperture in the electrical device, said screw assembly including a portion engaging and closing the switch when said screw assembly is tightened in said aperture. 48. A base module for a display of a plurality of electrical devices each having a respective operating voltage, said base module comprising: a power source transmitting DC electrical current at a first voltage; a plurality of electrical connector structures each with a plurality of electrical contacts, each electrical connector structure being configured to connect with a respective complementary electrical connector having a plurality of separate electrical contacts so as to transmit said DC electrical current to said complementary electrical connector to at least one of said contacts; two of said contacts of said electrical connector structures being connected with an alarm circuit, said alarm circuit detecting whether a circuit connected to said two contacts of the electrical connection structure is closed or open; said alarm circuit being configured to initiate an alarm-set condition of the alarm circuit responsive to an initial detection that the circuit connected to said two contacts is closed; said alarm circuit being configured to trigger an audible or visible alarm responsive to a determination during the alarm-set condition that the circuit between said two contacts is open. 49. The base module of claim 48, wherein the only electrical current transmitted through said electrical connection structures is the DC current at said first voltage, and an alarm sense signal transmitted to one of said two contacts by said alarm circuit for determining whether the circuit is open or closed. 50. The base module of claim 49, wherein said electrical connector structures are sockets configured to receive jacks therein. 51. The base module of claim 50, wherein the sockets are each six-pin ethernet sockets. 52. The base module of claim 48, wherein said base module further comprises a housing surrounding said electrical connector structures, said housing including a panel having openings therein through which cables can extend to connect with the connector structures. 53. The base module of claim 52, wherein the panel has structure configured to support the electrical devices thereon. 54. The base module of claim 48, wherein said power source receives AC current and converts it to said DC current. 55. The base module of claim 54, wherein said base module further comprises a backup battery connected with the alarm circuit so as to power the alarm circuit in the event that AC current to the base module is interrupted.
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RELATED APPLICATIONS This application asserts priority based on U.S. provisional patent application Ser. No. 60/485,263 filed by Opher Pail on Jul. 3, 2003. FIELD OF THE INVENTION This invention relates to the field of displays for electronic devices, and more particularly, to displays that support multiple devices to which electrical power is supplied for permitting consumers to try the equipment operating with electrical power. This invention especially relates to displays of multiple cameras or camcorders that customers in a store can actually use to select the best product to buy. BACKGROUND OF THE INVENTION Systems for displaying electronic devices in a store have been devised that supply electrical power to the devices so that a potential buyer can actually pick up and use the electronic device, such as a camcorder or camera, in the store before purchasing it, to select the best model for that particular customer. One such system is shown in U.S. Pat. No. 6,386,906 B1 to Burke (herein incorporated by reference). This system is configured to support several different electronic devices made by different manufacturers, which require different power cables and jacks, and often require different voltages. To supply the different voltages, the system has several transformers that convert 110 volt AC current to DC current at three voltages, e.g., 4.5, 7, and 8 volts. Each device is connected to a power supply base by a cable that carries the DC current for all three voltages. At the other end of the cable, an appropriate jack is provided connected to the appropriate conductor of DC for the required voltage of the associated electronic device. Systems of the prior art have the disadvantage that they support only devices that can work with the set of voltages provided by the transformers of the base power supply, and updating the system to other different voltage levels for new devices to be displayed requires modification of the circuitry of the base. There are many camcorders on the market, and they have a wide variety of voltages that are required, some being listed below in Table 1. It is not possible to provide such a wide range of possible voltages using systems of the prior art without substantial modifications. TABLE 1 Panasonic PV-DV53D 7.2 v Panasonic PV-DV353D 6 v JVC GR-SXM250V 11 v Canon ZR60A 8.4 v Sharp VL-NZ50 10 v Sharp WLAH151 7 v Olympus C-50 4.8 v HP 850 6 v Kodak LS443 5 v Olympus C-720 6.5 v Fuji 3800 5 v Kodak CX4230 3 v Olympus D-390 3.4 v Another drawback of the prior art is that the cable carrying power requires a number of wires, because there are three currents at different voltages, making the power cable heavier and more expensive. Also, the length of the cord can result in a substantial drop in voltage relative to the input voltage, due to resistance in the cable, with the output voltage being less than the input voltage, and possibly outside the proper working voltage range for the associated electronic device. SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a system for display of electronic devices to consumers that overcomes the disadvantages of the prior art, especially a system that allows for ready adaptation to electronic devices of any voltage and of any cable configuration. It is an object of the invention to provide a system for display of one or more electronic devices. Such a system for displaying a plurality of electronic devices can comprise a power supply providing input electrical current at a first voltage and a plurality of cable structures each being connected with the power supply so as to receive the input electrical current therefrom at the first voltage. Each cable structure has a respective power connector configured to electrically connect with the power receiving structure of a respective one of the electronic devices. The cable structures each also includes a respective voltage regulator system receiving the input electrical current, converting the input electrical current to a respective output electrical current at a respective output voltage, and transmitting the output electrical current to the power connector so as to transmit an operating electrical current to the associated electronic device. The voltage regulator system sets the output voltage of the output electrical current such that the operating electrical current delivered to the associated electronic device has a voltage that corresponds to the operating voltage of the electronic device. It is also an object of the invention to provide a method for displaying one or more electronic devices. Such a method may comprise providing a base module having a power supply with a plurality of electrical connector structures each supplied with DC current at a first voltage, securing to each electronic device a respective device module, and connecting a first cable between each device module and a respective electrical connector structure of the base module so that said first cables each carry said DC current at the first voltage to the associated device module. The device modules each have a respective voltage regulator receiving the DC current and converting the DC current to a respective output current. The method further comprises connecting a second cable between each device module and the electrical device secured thereto. The second cable receives the output current from the device module and transmits the output current to a power connector complementarily engaging and electrically connecting with the power input structure of said electrical device. The output current is transmitted to the electrical device at a voltage corresponding to the operating voltage of said device. Each of the voltage regulators sets the associated output current at a voltage that is dependent on an electrical characteristic of a respective calibrating component connected therewith. The calibrating component is part of the associated second cable connected with the device module. It is also an object of the invention to provide a module for attachment to an electronic device on display. A module of this invention may comprise a housing including a securement structure configured to secure the module to the electrical device. A power input is supported on the module and configured to be connected with a power input cable so as to receive therefrom an electrical current having an input voltage. A voltage regulator is supported in said housing and has an input and an output. The input is electrically connected with the power input so as to receive the electrical current therefrom. The voltage regulator is configured to convert the electrical current to an output current at an output voltage and to transmit the output current through the output. The voltage regulator has a calibrating input and is configured to set the output voltage of the output current dependent on an electrical characteristic of a calibrating component connected electrically with the calibrating input. A connector structure is electrically connected with the calibrating input of the voltage regulator. The connector structure is configured to releasably connect with a complementary connection structure so that a user can selectively connect to the voltage regulator a calibrating element having an electrical characteristic to cause the voltage regulator to set the output voltage to an appropriate voltage in view of the operating voltage of the electrical device. It is an object of the invention to provide a base module. In a preferred embodiment, the base module comprises a power source transmitting DC electrical current at a first voltage. A plurality of electrical connector structures, each with a plurality of electrical contacts, are configured to connect with a respective complementary electrical connector having a plurality of separate electrical contacts so as to transmit said DC electrical current to the complementary electrical connector to at least one of the contacts. Two of the contacts of the electrical connector structures are connected with an alarm circuit. The alarm circuit detects whether a circuit connected to the two contacts of the electrical connection structure is closed or open. The alarm circuit is configured to initiate an alarm-set condition of the alarm circuit responsive to an initial detection that the circuit connected to the two contacts is closed. The alarm circuit is configured to trigger an audible or visible alarm responsive to a determination during the alarm-set condition that the circuit between the two contacts is open. It is an object of the invention to provide a connector cable comprising a first electrical connector element having at least four electrical contacts configured to make four separate electrical connections when the first electrical connector element is secured in engagement with a complementary electrical connector structure. A cable portion has two opposite ends and two wires each connected with a respective one of said electrical contacts of the first electrical connector element. A device power input jack has at least two electrical contacts each connected electrically with a respective wire of the cable portion. The power input jack is configured to be matingly engaged with a power input structure of an electrical device so as to form an electrical connection therewith supplying electrical power to the electrical device at an operating voltage through said power input structure. A calibrating component is connected with two other contacts of the first electrical connector element so that a circuit containing the calibrating component is formed between the two contacts. The calibrating component has an electrical characteristic selected to cause a voltage regulator connected therewith to transmit electrical power at a voltage corresponding to the operating voltage of the electrical device. In a particularly preferred embodiment, the connector cable comprises a connector with four contacts, two of the contacts connecting with a calibrating component and at least one of the other contacts connecting with a power supply connector configured to be received in an electronic device so as to supply power thereto. It is similarly an object of the invention to provide such a connector cable wherein the calibrating component is adapted to co-act with a voltage regulator so as to cause the regulator to supply current at a first voltage, which voltage is appropriate for powering a device having a power receiving structure that is configured to fit with the power supply connector. It is further an object of the invention to provide a system for displaying one or more electronic devices comprising one or more of the above components. Other objects and advantages of the invention will become apparent from the disclosure herein. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a display system according to the invention; FIG. 2 is a diagram of a display system according to the invention; FIG. 3 is a detail view of the security module attached to the electronic device and the connector cord supplying power therefrom to the device; FIG. 4 is a perspective view of a one end of a connector cord according to the invention; FIG. 5 is an exploded diagram of a modified alternate arrangement of the system of the invention; FIG. 6 is a schematic of the circuitry inside the security module. FIG. 7 is a schematic of a connector cord linking the security module to the electronic device on the display. FIG. 8 is a schematic of an especially preferred embodiment of the connector cord linking the security module to the electronic device on the display. FIG. 9 is a detail view of the securement of a device module to an electronic device being displayed. FIG. 10 is a detail view of an alternate embodiment of securement of a device module to an electronic device being displayed. DETAILED DESCRIPTION As best shown in FIGS. 1 and 2, an electronic device display is illustrated for displaying to customers one or more electronic devices 3, which in the preferred embodiments are camcorders or cameras, connected by cable structures to a base module. Each camcorder 3 has secured thereto a device module or security circuit housing 5. The security module 5 has a connection structure or socket receiving the end of a flexible cable 7 that extends through an aperture 9 in a display cover plate 11, which encloses the display system so that the consumers do not see the power supply or other equipment supporting the display. The cable 7 is preferably a flexible coiled cable, or a cable with a spring loaded take-up reel or recoiler unit 7A. The cable has a distal end 13 with a connection structure that is plugged into one of a number of modular connection structures or sockets 15 in one or more power supply base modules 17. The base modules 17 are connected to each other by an expansion cord 19. The first of the base modules 17 is connected by power cable 21 to single voltage power supply 23, which is in turn connected to a power cable and plug 25 that connects to a wall socket and receives therefrom standard AC current, which in the United States is normally 110 volts. The power supply 23 converts the 110 volt AC to DC at a system operating voltage that is selected to be at least as high as the maximum voltage required to supply any electronic device 3 to be supported on the display. In the preferred embodiment, the DC voltage is 15 volts. The DC current flows through cable 21 to the first base module 17, to a PCB board therein that transmits the DC power to each of the multiple sockets 15, wired in parallel to share the power. There are preferably 16 to 25 socket outlets 15 in each base module 17. The expansion cable 19 is also wired in parallel, and transmits the DC current to the next base module 17, where the DC current is transmitted to the multiple sockets 15 thereof wired in parallel. All sockets 15 in both base modules receive the DC current at the same system operating voltage, e.g., 15 volts. Each of the sockets 15 is configured to receive a complementary connection structure or plug therein that is preferably an Ethernet-type jack that securingly clips into the socket 15 and provides six leads or electrical contacts coming from the socket 15. Two of these leads transmit the DC power at the system operating voltage. Two are preferably ground, and two of the leads connect with wires that are the in and out lines for a security circuit that is closed when the other end of the cable 7 is plugged into the security module 5, and the security module 5 is secured to the electronic device 3 displayed. If the security module 5 is separated from the device 3, it breaks the circuit, and if the cable 7 is detached from the security module 5, or if it is cut to release the device from the display, the security circuit is broken. Generally, the structure securing the security module 5 to the device 3 is a bolt screwed into the device 3, and the bolt closes the security circuit. If, to separate the device 3 from the security module, this bolt removed, there is an interruption in the circuit, creating an alarm condition. An example of such a structure can be seen in FIG. 5, which shows an exploded schematic diagram of the system with a molded support for the device 3, similar to the system of FIGS. 1 and 2 with similar parts having the same reference characters. Cable 7 extends through opening 9 and through a molded stalk base 29 mounted thereon. Stalk base 29 can supportingly receive thereon tubular stalk upper portion 31, which has an interior bore through which bolt 33 extends. Bolt 33 goes through security module 5 and bolts into device 3. Bolt 33 is part of the connection of the wires in cable 7, and tampering with it breaks the circuit, so as to create an alarm condition The PCB circuit in each base module 17 includes a main alarm circuit that illuminates a bi-color LED 26 for each of the sockets 15 selectively for different circuit conditions. During initial setup, the LED 26 for the circuit flashes green. Once a device is correctly plugged into the socket 15, the alarm circuit detects that the security circuit is completed by sending an alarm sense signal through the security circuit, and the LED is illuminated a steady green, indicating a key-on or alarm-set condition. If there is an unsafe line indication, e.g., the security circuit is not completed, the LED illuminates a steady red. Once the security circuit is completed and the LED is lit steady green, the alarm circuit continuously or periodically tests whether the security circuit is closed or open by sending an alarm sense signal through it. If the alarm circuit detects that the security circuit is open, i.e., cut, indicating, for example, that the device 3 has been unplugged or the cable 7 has been cut, it triggers an alarm condition and activates a visible or audible alarm. Preferably, the base module 17 has an audible alarm (preferably a very loud one) that alerts store personnel, and, during the alarm condition, the LED illuminates a flashing red. The alarm can be turned off by an operator control, such as remote 27 (FIG. 2) or key switch 35 (FIG. 5). The base module can also be connected with an auxiliary alarm to enhance the alert, such as by an even louder alarm system or a brighter visible alarm light. The base module 17 also has a rechargeable battery power supply that maintains some aspects of the system, e.g., the security alarm, independent of the supply of AC power to the transformer 23, and any control circuitry, such as the key switch with which an operator can turn the system on or off with a key. Referring to FIG. 2, security module or device module 5 has an input connection structure or socket receiving the end of cable 7. This socket is preferably also a six-wire Ethernet-type female socket that matingly receives a complementary connection structure in the form of male Ethernet jack 36 at the end of cable 7 (see FIG. 3). This socket connects the six wires of cable 7 to a PCB circuit board housed in the security module 5. FIG. 6 illustrates the circuit and its functionality. The socket 37 connects with the six wires of cable 7. Pins 1 and 3 are the positive power input delivering DC current from the base module at the system operating voltage, in the preferred embodiment, 15 volts DC power. Pins 2 and 4 are power ground, or alternatively, the opposing pole of the power of respectively, pins 1 and 3. Pin 5 is signal ground for the alarm sense signal and a jumper to pin 4 to use as a cable sense. Pin 6 represents the lead receiving the alarm sense signal. Preferably, to minimize noise the cable is organized as three twisted pairs of wires, i.e., pins 1 and 2, pins 3 and 4, and pins 5 and 6. Pins 1 and 3 are involved in sending power to the device 3. DC current at the system DC operating voltage, e.g., 15 volts, flows in and through line 41 to adjustable switching voltage regulator 43. This voltage regulator 43 converts the voltage in line 41 to the appropriate voltage for the device 3 and transmits the resulting output current through a power output of regulator 43. The voltage regulator 43 in the preferred embodiment is sold by Micrel, Inc., of 1849 Fortune Drive, San Jose, Calif. 95131 under the designation MIC4684, called the 2A high-efficiency SuperSwitcher™ Buck Regulator. Adjustable switching voltage regulator 43 has four lines indicated at 45 that run to a connection structure 47 in the form of standard modular 4-point telephone jack socket at one end of connector cable 48. As a more preferable alternative, a USB socket (not shown) may be used instead of a telephone jack, as the USB jack and socket assembly is smaller and reduces the size of the module 5. This socket 47 receives a complementary connection structure in the form of male 4-point jack 49, best shown in FIGS. 3 and 4. This jack 49 is connected with two two-wire cables 51 and 53. Cable 51 is preferably 24/26A WG or 24 gauge two-wire cable, and it carries the DC power to a connection structure or jack 55 that is plugged into the power input connection structure or socket generally indicated at 57 of the device 3. The connection structure or jack 55 is configured to matingly connect with the specific and particular type of connection structure or socket in the device 3, and is configured to match the power input jack of the particular manufacturer of the device for that device. These jacks vary substantially from manufacturer to manufacturer. Pins 1 and 2 are the power-in (positive voltage) and power-out (negative voltage) lines that send the output DC current from regulator 43 to the device 3, and these connect with the jack 55 through the two wires or lines 59 and 61 of cable 51. Pins 3 and 4 of the jack 49 connect a calibrating voltage set input of voltage regulator 43 through wire 53 to a regulator calibrating component 63, which is preferably a resistor, and that co-acts with the regulator 43 to set the voltage level of the DC power output of regulator 43 sent to pins 1 and 2. For different values of an electrical characteristic, e.g., resistance of regulator calibrating component 63, the regulator 43 produces different output voltages. Where the voltage programming component 63 is a resistor, the voltage is low enough that only a minor amount of heat is released. Preferably, the resistor is a ⅛ or ¼ W resistor with an appropriate resistance value, with a 1% tolerance. In the preferred embodiment, the connector structure is a male USB jack with a molded body. The calibrating component 63 is supported in the body of the USB jack 49, preferably embedded in the plastic molding so as to be invisible to the user, and less exposed to damage. The connector cable 48 is thus formed of a four-point jack, a calibrating component 63 that sets the appropriate output voltage that the regulator should generate for the specific device 3, and a power supply line to a jack configured to be received in the power input connection structure 57 of the specific device 3. The cable is consequently unique to the device 3 or to the set of devices that use the same input structure and voltage, usually a group of products by the same manufacturer. This connector cable is preferably identifiable by a color coded marking, such as tag 65, or else a coloring of the cables, such as one color indicating a particular voltage and the other the shape of power input jack. Another embodiment of the connector cable 48 is seen in FIG. 8. In this embodiment, the power input connector structure is preferably an injection-molded plastic structure enclosing the requisite electronic components for connecting to and powering device 3. In addition, this plastic housing 64 preferably contains the resistor or calibrating component 63 that sets the appropriate output voltage for the device 3 imbedded therein. The four-wire cable is relatively easy to assemble with the components. The plastic housing is preferably configured to resemble the normal manufacturer's jack for the device, with the component 63 not visible to the consumer testing the product. The security module circuit board shown in FIG. 5 also provides additional security features similar or complementary to those of the base module 17. Pin 6 is connected to the security circuit portion in the module 5, and transmits an alarm sense signal along a line to tamper switches 67 that are both closed when the device 3 is secured to the device module 5. If either tamper switch 67 should open, indicating that the device is somehow separated from the security module 5, this is detected at the base module, and creates an alarm condition, intended to occur when the device is separated from the security module or the cable 7 to the base module 17 is cut. When the security circuit is broken, the alarm sense line 69 is activated, and microcontroller 71 causes the LED 73 to flash red, and also activates or enables the buzzer alarm circuit 75, which generates a loud alarm. This alarm is powered by the battery 77, preferably a 9 volt alkaline battery, whether or not power is being received from the cable 7. The DC power received from cable 7 is also directed to the microcontroller 71 over a power sense line enabling the microcontroller to determine if the module 5 is receiving power from the cable 7. The DC power is also transmitted through an isolation diode to power the buzzer system 75, and to a 5 volt voltage regulator, which converts the voltage to 5 volts DC current and uses this to power the integrated circuits and chips of the PCB board in the module 5. The battery 77 is also connected with the 5 volt voltage regulator to power the ICs if the power from cable 7 is interrupted. The power is transmitted to the 5 volt regulator and buzzer through an isolation diode. A low-battery detection component is also electrically connected with the battery, providing an input to the microcontroller 71 that enables it to alert a user of the need for a recharge or replacement of the battery 77. Microcontroller chip 71 also provides for other control of the LED 75 to show whether power is being received at the circuit from cable 7 (a steady green LED), and whether the battery is low (flashing red with no buzzer). With small electrical devices especially, it may be desired to reduce the size of the device module 5 as much as possible. A substantial reduction of size can be achieved by eliminating the alarm circuitry in the device module 5, i.e., eliminating the alarm sense line 69, the audible alarm circuit 75, the buzzer, and the battery 77. When these are eliminated, if someone detached the electrical device 3 from the module 5 or cuts the wire, or otherwise breaks the security circuit, the alarm circuit of the base module is relied on to serve as the alarm system. The securement structure that is preferably used to secure the device module 5 to the electronic device 3 is shown best in FIG. 9. The module 5 has a housing 81 that supports the PCB board 83 therein. A cover plate 84 covers the bottom of the housing 81 to restrict access to the interior thereof. The securement assembly comprises a securement member in the form of bolt 85 that is inserted through access opening 86 in cover plate 84, extends through a washer 87 with a hole in it, through an opening in the PCB board 83, and through an opening 89 in the housing 83, where it threadingly engages the device 3 in a threaded aperture 91 therein, which is preferably the threaded aperture provided in video cameras and other electronic devices for functions such as mounting on a tripod or other support. Bolt 85 is tightened by a special tool similar to an Allen wrench through opening 86 to firmly secure the module 5 to device 3. The board 83 is supported fixedly in the position shown by the housing 81, and, when tightened, the bolt 85 presses against washer 87, which overlies the two tamper switches 67 on the PCB board 83. The tamper switches are biased by a spring or other means to the open (circuit broken) state thereof. However, the washer 87 presses on the tamper switches 67 against the urging of the springs, and closes them so as to complete the security circuit. If bolt 85 were to be unscrewed from the device by a customer trying to detach the device, it would release pressure on the washer 87, permitting the tamper switches 67 to open, breaking the circuit, and triggering an alarm condition. An alternate embodiment is shown in FIG. 10, wherein the module 5 is secured to the device 3 via an adapter 93. The adapter 93 is configured to be secured to the device 3 by whatever structure or other means necessary, such as adhesive, for example, or by a structural interlock with the device 3. The configuration of the adapter depends on the configuration of the device 3. A variety of connection structures can be used advantageously in this area, as will be clear to one of skill in the art. The primary consideration should be that the adapter 93 is very difficult to remove from the device 3. The adapter 93 has a threaded bore 95 therein that screwingly receives bolt 85. Bolt 85 presses on washer 87 as in the embodiment of FIG. 9, closing tamper switches 67, and closing the security circuit. Any loosening or removal of the bolt 85 from adapter 93 to free the device 3 from module 5 will open the tamper switches 67 and trigger the alarm. The terms used herein should be considered terms of description rather than limitation, as those of ordinary skill in the art, having this disclosure before them, will be able to make adjustments and modifications therein without departing from the spirit of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Systems for displaying electronic devices in a store have been devised that supply electrical power to the devices so that a potential buyer can actually pick up and use the electronic device, such as a camcorder or camera, in the store before purchasing it, to select the best model for that particular customer. One such system is shown in U.S. Pat. No. 6,386,906 B1 to Burke (herein incorporated by reference). This system is configured to support several different electronic devices made by different manufacturers, which require different power cables and jacks, and often require different voltages. To supply the different voltages, the system has several transformers that convert 110 volt AC current to DC current at three voltages, e.g., 4.5, 7, and 8 volts. Each device is connected to a power supply base by a cable that carries the DC current for all three voltages. At the other end of the cable, an appropriate jack is provided connected to the appropriate conductor of DC for the required voltage of the associated electronic device. Systems of the prior art have the disadvantage that they support only devices that can work with the set of voltages provided by the transformers of the base power supply, and updating the system to other different voltage levels for new devices to be displayed requires modification of the circuitry of the base. There are many camcorders on the market, and they have a wide variety of voltages that are required, some being listed below in Table 1. It is not possible to provide such a wide range of possible voltages using systems of the prior art without substantial modifications. TABLE 1 Panasonic PV-DV53D 7.2 v Panasonic PV-DV353D 6 v JVC GR-SXM250V 11 v Canon ZR60A 8.4 v Sharp VL-NZ50 10 v Sharp WLAH151 7 v Olympus C-50 4.8 v HP 850 6 v Kodak LS443 5 v Olympus C-720 6.5 v Fuji 3800 5 v Kodak CX4230 3 v Olympus D-390 3.4 v Another drawback of the prior art is that the cable carrying power requires a number of wires, because there are three currents at different voltages, making the power cable heavier and more expensive. Also, the length of the cord can result in a substantial drop in voltage relative to the input voltage, due to resistance in the cable, with the output voltage being less than the input voltage, and possibly outside the proper working voltage range for the associated electronic device.
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<SOH> SUMMARY OF THE INVENTION <EOH>It is therefore an object of the invention to provide a system for display of electronic devices to consumers that overcomes the disadvantages of the prior art, especially a system that allows for ready adaptation to electronic devices of any voltage and of any cable configuration. It is an object of the invention to provide a system for display of one or more electronic devices. Such a system for displaying a plurality of electronic devices can comprise a power supply providing input electrical current at a first voltage and a plurality of cable structures each being connected with the power supply so as to receive the input electrical current therefrom at the first voltage. Each cable structure has a respective power connector configured to electrically connect with the power receiving structure of a respective one of the electronic devices. The cable structures each also includes a respective voltage regulator system receiving the input electrical current, converting the input electrical current to a respective output electrical current at a respective output voltage, and transmitting the output electrical current to the power connector so as to transmit an operating electrical current to the associated electronic device. The voltage regulator system sets the output voltage of the output electrical current such that the operating electrical current delivered to the associated electronic device has a voltage that corresponds to the operating voltage of the electronic device. It is also an object of the invention to provide a method for displaying one or more electronic devices. Such a method may comprise providing a base module having a power supply with a plurality of electrical connector structures each supplied with DC current at a first voltage, securing to each electronic device a respective device module, and connecting a first cable between each device module and a respective electrical connector structure of the base module so that said first cables each carry said DC current at the first voltage to the associated device module. The device modules each have a respective voltage regulator receiving the DC current and converting the DC current to a respective output current. The method further comprises connecting a second cable between each device module and the electrical device secured thereto. The second cable receives the output current from the device module and transmits the output current to a power connector complementarily engaging and electrically connecting with the power input structure of said electrical device. The output current is transmitted to the electrical device at a voltage corresponding to the operating voltage of said device. Each of the voltage regulators sets the associated output current at a voltage that is dependent on an electrical characteristic of a respective calibrating component connected therewith. The calibrating component is part of the associated second cable connected with the device module. It is also an object of the invention to provide a module for attachment to an electronic device on display. A module of this invention may comprise a housing including a securement structure configured to secure the module to the electrical device. A power input is supported on the module and configured to be connected with a power input cable so as to receive therefrom an electrical current having an input voltage. A voltage regulator is supported in said housing and has an input and an output. The input is electrically connected with the power input so as to receive the electrical current therefrom. The voltage regulator is configured to convert the electrical current to an output current at an output voltage and to transmit the output current through the output. The voltage regulator has a calibrating input and is configured to set the output voltage of the output current dependent on an electrical characteristic of a calibrating component connected electrically with the calibrating input. A connector structure is electrically connected with the calibrating input of the voltage regulator. The connector structure is configured to releasably connect with a complementary connection structure so that a user can selectively connect to the voltage regulator a calibrating element having an electrical characteristic to cause the voltage regulator to set the output voltage to an appropriate voltage in view of the operating voltage of the electrical device. It is an object of the invention to provide a base module. In a preferred embodiment, the base module comprises a power source transmitting DC electrical current at a first voltage. A plurality of electrical connector structures, each with a plurality of electrical contacts, are configured to connect with a respective complementary electrical connector having a plurality of separate electrical contacts so as to transmit said DC electrical current to the complementary electrical connector to at least one of the contacts. Two of the contacts of the electrical connector structures are connected with an alarm circuit. The alarm circuit detects whether a circuit connected to the two contacts of the electrical connection structure is closed or open. The alarm circuit is configured to initiate an alarm-set condition of the alarm circuit responsive to an initial detection that the circuit connected to the two contacts is closed. The alarm circuit is configured to trigger an audible or visible alarm responsive to a determination during the alarm-set condition that the circuit between the two contacts is open. It is an object of the invention to provide a connector cable comprising a first electrical connector element having at least four electrical contacts configured to make four separate electrical connections when the first electrical connector element is secured in engagement with a complementary electrical connector structure. A cable portion has two opposite ends and two wires each connected with a respective one of said electrical contacts of the first electrical connector element. A device power input jack has at least two electrical contacts each connected electrically with a respective wire of the cable portion. The power input jack is configured to be matingly engaged with a power input structure of an electrical device so as to form an electrical connection therewith supplying electrical power to the electrical device at an operating voltage through said power input structure. A calibrating component is connected with two other contacts of the first electrical connector element so that a circuit containing the calibrating component is formed between the two contacts. The calibrating component has an electrical characteristic selected to cause a voltage regulator connected therewith to transmit electrical power at a voltage corresponding to the operating voltage of the electrical device. In a particularly preferred embodiment, the connector cable comprises a connector with four contacts, two of the contacts connecting with a calibrating component and at least one of the other contacts connecting with a power supply connector configured to be received in an electronic device so as to supply power thereto. It is similarly an object of the invention to provide such a connector cable wherein the calibrating component is adapted to co-act with a voltage regulator so as to cause the regulator to supply current at a first voltage, which voltage is appropriate for powering a device having a power receiving structure that is configured to fit with the power supply connector. It is further an object of the invention to provide a system for displaying one or more electronic devices comprising one or more of the above components. Other objects and advantages of the invention will become apparent from the disclosure herein.
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20040701
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20060321
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20050106
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87035.0
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SQUIRES, BRETT
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ELECTRONIC DEVICE DISPLAY SYSTEM AND METHOD
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UNDISCOUNTED
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ACCEPTED
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10,883,667
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ACCEPTED
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Recording medium, method of configuring control information thereof, recording and/or reproducing method using the same, and apparatus thereof
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The present invention provides a method of recording control information in a recordable optical disc including at least one recording layer. In recording control information within a management area of an optical disc including at least one or more recording layers, the present invention includes providing the control information to each of the at least one or more recording layers per recording velocity, recording an information identifying a type of the corresponding control information within the control information, and recording a write strategy (WS) interworking with the type of the control information. In recording a write strategy (WS) within disc information, CLV and CAV are separately recorded, whereby it is able to efficiently cope with the record/playback of the optical disc.
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1. A method of recording control information on a recording medium, comprising the steps of: generating a control information associated with at least one or more recording layers and recording velocities, the control information including first information identifying a type of the corresponding control information, the information indicating whether the control information is used for CLV (constant linear velocity) or CAV(constant angular velocity), and a write strategy parameters associated with the type of the control information; and recording the control information on a specific area of the recording medium. 2. The method of claim 1, wherein the control information further includes write strategy parameters associated with CLV (constant linear velocity) or CAV (constant angular velocity). 3. The method of claim 2, wherein the control information further includes second information identifying a number of velocities associated with the write strategy parameters if the first information identifies the control information for CAV (constant angular velocity). 4. The method of claim 3, wherein respective write strategy parameters associated with the respective velocities are included in the control information. 5. The method of claim 2, wherein the control information includes the write strategy parameters associated with one recording velocity if the first information identifies the control information for CLV (constant linear velocity). 6. The method of claim 1, wherein the control information further includes third information identifying a type of the write strategy. 7. The method of claim 6, wherein at least two types of the write strategies exist. 8. The method of claim 7, wherein one of the specified types of the write strategy is optionally included in the control information. 9. The method of claim 6, wherein the write strategy parameters for a predetermined specific velocity of the control information is recorded based on a previously decided the write strategy type in a mandatory manner. 10. The method of claim 6, wherein the write strategy parameters associated with the type of control information and the write strategy type are included in the control information. 11. The method of claim 1, wherein the control information is recorded in an embossed area of the recording medium. 12. The method of claim 1, wherein the control information is recorded in a recordable area of the recording medium. 13. A data structure of a control information recorded on a recording medium or to be recorded/reproduced on/from the recording medium, characterized in that the control information associated with a specific recording layer and/or a specific recording velocity and the control information comprises write strategy information dependent on a type information indicating whether the control information is associated with CAV or CLV. 14. The data structure of claim 13, wherein the control information further includes write strategy parameters associated with CLV (constant linear velocity) or CAV (constant angular velocity). 15. The data structure of claim 14, wherein the control information further includes an identification information identifying a number of velocities associated with the write strategy parameters if the type information identifies the control information for CAV (constant angular velocity). 16. The data structure of claim 15, wherein respective write strategy parameters associated with the respective velocities are included in the control information. 17. The data structure of claim 14, wherein the control information includes the write strategy parameters associated with one recording velocity if the type information identifies the control information for CLV (constant linear velocity). 18. The data structure of claim 13, wherein the control information further includes a strategy information identifying a type of the write strategy. 19. The data structure of claim 18, wherein at least two types of the write strategies exist. 20. The data structure of claim 19, wherein one of the specified types of the write strategy is optionally included in the control information. 21. The data structure of claim 18, wherein the write strategy parameters for a predetermined specific velocity of the control information is recorded based on a previously decided the write strategy type in a mandatory manner. 22. The data structure of claim 18, wherein the write strategy parameters associated with the type of control information and the write strategy type are included in the control information. 23. A recording medium comprising: at least one recording layer provided with a recordable area and a pre-recorded area, wherein a disc information is separately provided according to each recording velocity and/or each recording layer to the pre-recorded area and wherein an identification information identifying a type of the disc information therein and a write strategy information associated with the identification information therein are provided to the disc information. 24. An optical disc comprising: at least one or more recording layers, wherein a control information is provided according to each recording layer and/or each recording velocity, wherein an identification information identifying a type of the control information and a write strategy parameters associated with the identification information are recorded within the control information. 25. The optical disc of claim 24, wherein the identification information is to identify whether a recording type is CLV (constant linear velocity) or CAV (constant angular velocity). 26. The optical disc of claim 24, wherein information identifying a type of the write strategy is further recorded within the control information. 27. The optical disc of claim 26, wherein the write strategy parameters are associated with the identification information and the write strategy type. 28. A method of recording data on a recording medium, comprising the steps of: reading a plurality of control information separately recorded according to each recording velocity within a management area of the recording medium; checking an identification information identifying a control information type recorded within each control information; and performing a recording of data based on a write strategy information associated with a corresponding recording velocity from the identification information. 29. A method of recording data on a recording medium, comprising the steps of: identifying a specific control information based on an identification information identifying a type of control information, wherein the control information associated with specific recording velocity and/or specific recording layer to provide a reference information for recording or reading of data, the identification information identifying whether the control information is used for CLV or CAV; and recording data using write strategy parameters included in the control information to be used for CLV or CAV as a result of identifying step. 30. The method of claim 29, wherein the identifying step further identifies a type information indicating a specific write strategy type, wherein the write strategy parameters associated with the identification information and the type information. 31. The method of claim 30, wherein the recording step records data using write strategy parameters. 32. An apparatus for recording data on a recording medium, comprising: an optical pickup reading a plurality of control information associated with at least recording velocity within a management area of the recording medium; and a controller checking a control information type based on an identification information to identify whether the corresponding control information is used for CLV or CAV, reading a write strategy included in the corresponding control information as a result of the checking step, and performing the recording of data using the read write strategy. 33. The apparatus of claim 32, wherein the controller controls the recording of data at a corresponding recording velocity. 34. The apparatus of claim 32, wherein the controller further checks a control information type based on a write strategy type identified by a type information, reads a write strategy associated with the write strategy type from the corresponding control information, and performs the recording of data using the write strategy. 35. The apparatus of claim 32, wherein the controller controls a servo operation based on the control information for CLV or CAV.
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This application claims the benefit of the Korean Application No. 10-2003-0045825 filed on Jul. 7, 2003 and No. 10-2003-0056540 filed on Aug. 14, 2003 and No. 10-2003-0061785 filed on Sep. 4, 2003, which are hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recording control information on a recording medium, such as a recordable optical disc, and a method of recording data on a recording medium using the control information. 2. Discussion of the Related Art A high-density optical recording medium, known as HD-DVD, is widely used to record and store high-definition video data and high-quality audio data. The Blu-ray disc (hereinafter abbreviated BD) represents next-generation HD-DVD technology. Technological specifications are now being established for the global standardization of the Blu-ray disc, including standards for a write-once Blu-ray disc (BD-WO). Meanwhile, a rewritable Blu-ray disc, known as 1× speed BD-RE and now under discussed should be compatible with BD-RE discs expected to have higher writing speed, i.e., 2× speed BD-RE and beyond. BD-WO specifications for high writing speed are also in progress. Efficient solutions for coping with the high writing speed of a high-density optical disc are urgently needed, and the specifications established should ensure mutual compatibility. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a method of recording control information in an optical disc that substantially obviates one or more problems due to limitations and disadvantages of the related art. An object of the present invention is to provide a new method of recording control information as specified information coping with high writing speed, in which information indicating a kind of control information is recorded within the control information as well as a write strategy interworking with the recorded information. Another object of the present invention is to define a new data structure configuring control information. Another object of the present invention is to provide a specified method of recording control information coping with high writing speed in a specific area within a disc, by which reciprocal compatibility is provided between the same based discs. A further object of the present invention is to provide a recording/reproducing method and apparatus thereof, by which real data is recorded/reproduced on/from an optical disc using the recorded control information. Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method of recording control information on a recording medium according to the present invention includes the steps of generating a control information associated with at least one or more recording layers and recording velocities, the control information including first information identifying a type of the corresponding control information, the information indicating whether the control information is used for CLV (constant linear velocity) or CAV(constant angular velocity), and a write strategy parameters associated with the type of the control information; and recording the control information on a specific area of the recording medium. In another aspect of the present invention, A data structure of a control information recorded on a recording medium or to be recorded/reproduced on/from the recording medium, characterized in that the control information associated with a specific recording layer and/or a specific recording velocity and the control information comprises write strategy information dependent on a type information indicating whether the control information is associated with CAV or CLV. In another aspect of the present invention, a recording medium includes at least one recording layer provided with a recordable area and a pre-recorded area, wherein a disc information is separately provided according to each recording velocity and/or each recording layer to the pre-recorded area and wherein an identification information identifying a type of the disc information therein and a write strategy information associated with the identification information therein are provided to the disc information. In another aspect of the present invention, An optical disc includes at least one or more recording layers, wherein a control information is provided according to each recording layer and/or each recording velocity, wherein an identification information identifying a type of the control information and a write strategy parameters associated with the identification information are recorded within the control information. In another aspect of the present invention, a method of recording data on a recording medium includes the steps of reading a plurality of control information separately recorded according to each recording velocity within a management area of the recording medium, checking an identification information identifying a control information type recorded within each control information, and performing a recording of data based on a write strategy information associated with a corresponding recording velocity from the identification information. In another aspect of the present invention, a method of recording data on a recording medium includes the steps of identifying a specific control information based on an identification information identifying a type of control information, wherein the control information associated with specific recording velocity and/or specific recording layer to provide a reference information for recording or reading of data, the identification information identifying whether the control information is used for CLV or CAV, and recording data using write strategy parameters included in the control information to be used for CLV or CAV as a result of identifying step. In another aspect of the present invention, an apparatus for recording data on a recording medium includes an optical pickup reading a plurality of control information associated with at least recording velocity within a management area of the recording medium; and a controller checking a control information type based on an identification information to identify whether the corresponding control information is used for CLV or CAV, reading a write strategy included in the corresponding control information as a result of the checking step, and performing the recording of data using the read write strategy. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: FIG. 1 is a diagram of a single-layer disc applicable to the present invention; FIG. 2 is a diagram of a dual-layer disc applicable to the present invention; FIG. 3 is a diagram of a management area where control information of the present invention is recorded, in which a format of the disc information in a corresponding area is schematically shown; FIG. 4 is a diagram of control information recorded according to one embodiment of the present invention; FIG. 5 is a diagram of a write strategy within control information recorded according to one embodiment of the present invention in FIG. 4; FIG. 6 is a diagram of control information recorded according to another embodiment of the present invention; FIG. 7 is a diagram of control information recorded according to a further embodiment of the present invention; FIG. 8 is a diagram of a write strategy within control information recorded according to the further embodiment of the present invention in FIG. 7; FIG. 9 is a diagram of another example of a write strategy within control information recorded according to the further embodiment of the present invention in FIG. 7; FIG. 10 is a diagram of control information recorded according to another further embodiment of the present invention; FIG. 11 is a diagram of a write strategy within control information recorded according to the another further embodiment of the present invention in FIG. 10; and FIG. 12 is a block diagram of an optical disc recording/reproducing apparatus according to the present invention. DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. A Blu-ray disc is taken as an example of an optical disc according to the present invention. Yet, the concept of the present invention, characterized in an optical disc having its control information recorded thereon, is applicable to DVD-RAM, DVD-RW, DVD+RW, DVD-R, DVD+R and similar such discs. Although the terminology used herein is well known for the most part, some terms have been chosen by the applicant, such that the present invention should be understood with the intended meanings of the terminology as used by the applicant. For example, the ‘control information’ of a disc is recorded in a specified area, i.e., a recordable area of the disc or a prerecorded area, sometimes known as an embossed area, in which manufacturer data is recorded and where no further recording is possible, and includes information necessary for the playback of a recorded disc. Disc control information is called “disc information” or “DI” in relation to Blu-ray disc technology but is typically referred to as ‘physical format information’ for DVD-RAM, DVD-RW, DVD+RW, DVD-R, DVD+R discs. Hence, it should be apparent that the technical background of the present invention is equally applicable to physical format information. Moreover, the disc information according to the present invention is recorded as an unspecified unit of information, which may be counted, for example, as a first or second information. The present invention is characterized in that a write strategy (WS) is recorded by interworking with information that identifies a kind of disc information in recording the write strategy (WS) within disc information, one of a plurality of write strategy types is selectively recorded on manufacturing a disc, and a recording/reproducing apparatus (FIG. 12) performs recording/reproducing by referring to the write strategy (WS) recorded within the disc information. Preferentially, the meaning of ‘write strategy (WS)’ used in the description of the present invention is explained in detail as follows. Considering the meaning of ‘write strategy (WS)’, a medium property of a recording layer is generally modified by applying a laser beam to the recording layer within an optical disc via a pickup (‘11’ in FIG. 12) to perform a recording thereof. Hence, it should be decided a strength (write power) of the laser beam, a time of applying the write power thereto, and the like. The above decided various kinds of record-associated information are named ‘write strategy (WS)’ in general and specific contents recorded within a specific ‘write strategy (WS)’ are named ‘write strategy (WS) parameters’. Write strategy (WS) information used in the present invention means the entire information associated with write strategy (WS). And, ‘WS parameters’ means items and specific numeric values configuring the WS and is a sort of WS information. Hence, the WS information has an inclusive concept including the above-described ‘WS Type’, ‘WS flag’ that will be explained later, and the like as well as the WS parameters. And, the write strategy (WS) can be recorded in various ways. As a disc tends to be highly densified and to run at higher speed, a writing speed, i.e., disc RPM) as well as the medium property of the recording layer is considerably affected. Hence, a more accurate system is requested. And, the various write strategies (WS) are explained as follows for example. First of all, there is a system having a recording pulse smaller by 1 than a recording mark size (n) formed on a recording layer medium, which may be called ‘(n−1) WS’. Secondly, there is a system having a recording pulse having a size amounting to a half of the recording mark size (n), which may be called ‘n/2 WS’. Besides, new write strategies (WS) keep being developed. Regarding the different types of write strategies (WS), when there exist the various systems of the write strategy (WS) as parameters applied to the write strategies (WS) differ from each other, a disc manufacturer selects a specific WS to test write power according to write strategy parameters and then records a result of the test in ‘WS parameters’ field in a specific area within the disc information. Moreover, as a method of recording data on a disc, there are a constant linear velocity (hereinafter abbreviated CLV) method and a constant angular velocity (hereinafter abbreviated CAV) method. The CLV method applies the same linear velocity to inner and outer circumferential areas of a disc to perform a recording at one recording velocity. The CAV method applies the same RPM to inner and outer circumferences of a disc, whereby linear speed in the outer circumference of the disc having a relatively smaller rotational radius of the disc increases faster than that in the inner circumference of disc having a relatively greater rotational radius. When the radiuses of the inner and outer circumferences are compared to each other, there exists about 2.4 times difference between recording velocities of the inner and outer circumferences of the disc. Hence, in adopting the CAV system, a recording is performed at about 2.4× speed on the outer circumference and at 1× speed on the inner circumference. For example, the recording is performed on the inner circumference at 4× speed, whereas performed on the outer circumference at about 9.6× speed. Since there exists a big difference between the recording velocities of the inner and outer circumferences of the disc, it is necessary to select an optimal recording velocity and write strategy (WS) to be applied to each location of the disc to perform a recording thereon. Hence, the CAV method needs definitions for about three kinds of linear velocities (writing speed) such as 1× linear velocity, 1.7× linear velocity, and 2.4× linear velocity, which can be called ‘one type recording velocity group’. And, a write strategy (WS) for each of the defined recording velocities should be recorded within disc information. FIG. 1 and FIG. 2 are structural diagrams of optical discs according to the present invention, in which a recordable optical disc is enough to be the optical disc applicable to the present invention. Moreover, the recordable disc can be any one of a rewritable optical disc, a write-once optical disc, and the like. FIG. 1 is a structural diagram of a single-layer disc having one recording layer according to the present invention. Referring to FIG. 1, a lead-in area is provided as a management area on an inner circumference area of an optical disc, whereas a lead-out area is provided as a management area on an outer circumference area of the optical disc. Specifically, a prerecorded area and a rewritable or write-once area are separated from each other within the inner circumference area of the disc. The prerecorded area is an area (called ‘embossed area’) where data was already written in manufacturing the disc, whereby a user or system is unable to perform data writing on the prerecorded area at all. In BD-RE/WO, the prerecorded area is named PIC (permanent information and control data) area. And, the above-described disc information (hereinafter called ‘DI’) as information required for disc recording is recorded in the PIC area. In a data area, provided are a user data area where user's real data is recorded and spare areas ISA and OSA to replace a generated defect area. Specifically, TDMA (temporary defect management area) for recording information of defect and general managements is provided to such a write-once optical disc as BD-WO. In case of the re-writable BD (BD-RE), TDMA is unnecessary so that such an area is left as a reserved area. The present invention intends to provide a method of efficiently recording disc information (DI) as control information required for record playback of a disc in the prerecorded or recordable area. It is apparent that a recording method in the prerecorded area is differently applied to each kind of discs. In case of BD-RE/WO, the PIC area as the prerecorded area is recorded by biphased high frequency modulated signals, the high frequency modulated signals in the corresponding area are played back according to a specific playback method, and information is acquired from the playback. FIG. 2 is a diagram of a dual-layer disc having dual recording layers, in which a recording layer starting with a lead-in is named a first recording layer Layer0 and a recording layer ending with a lead-out is named a second recording layer Layer1. In the dual-layer disc, the PIC area is provided to lead-in and lead-out areas of a disc inner circumference area, and disc information (DI) of the same contents is recorded in the PIC area. FIG. 3 is a structural diagram of a PIC area in the disc shown in FIG. 1 or FIG. 2. As mentioned in the foregoing description, it means that information can be rearranged like the structure of the PIC area in FIG. 3 when the entire information within the high frequency modulated PIC area is acquired. A method of configuring disc information (DI) in the PIC area is explained in detail as follows. In BD-RE/WO, ‘one cluster’ represents a minimum record unit, five hundred forty-four clusters gather to construct one fragment as one upper record unit, and total five fragments gather to form the PIC area. Disc information is recorded in a front head cluster of a first fragment IF0. The disc information is plurally recorded per recording layer and writing speed permitted by the corresponding optical disc, and one disc information includes one hundred twelve bytes. Specifically, disc information constructed with 112-bytes is called disc information (DI) frame. Moreover, the same contents of the disc information are repeatedly recorded in each front head cluster of the rest of the fragments, thereby enabling to cope with loss of the disc information. Information representing the corresponding recording layer, information representing writing speed, and write strategy information corresponding to the writing speed are recorded within each disc information. Hence, such information is utilized in the recording or reproducing of the corresponding optical disc, thereby enabling to provide optimal write power per recording layer and per writing speed. Various embodiments for a method of recording a write strategy (WS) associated with a disc information type within disc information according to the present invention are explained in detail by referring to FIGS. 4 to 12 as follows. FIG. 4 is a diagram of recording disc information of an optical disc according to one embodiment of the present invention, in which a disc information structure is schematically shown. Referring to FIG. 4, a plurality of disc information are recorded within a disc, a record sequence of each disc information is decided by a sequence number, and the record sequence is recorded by 1-byte. For instance, the corresponding information is recorded in 5th byte within the disc information, which is named ‘DI frame sequence number in DI block’ field and is briefly indicated by ‘00h, 01h, 02h, 03h . . . ’. Namely, if the information of the 5th byte is ‘00h’, it means 1st disc information. And, if the information of the 5th byte is ‘07h’, it means 8th disc information. Moreover, the meaning of ‘DI frame sequence number in DI block’ of the 5th byte can be defined in a following manner. First of all, if the information of the 5th byte is ‘00h’, ‘00h’ means 1st disc information as well as disc information of 1× speed of a first recording layer Layer0. ‘01h’ means 2nd disc information as well as disc information of 2× speed of the first recording layer Layer0. ‘02h’ means 3rd disc information as well as disc information of 4× speed of the first recording layer Layer0. And, ‘03h’ means 4th disc information as well as disc information of 8× speed of the first recording layer Layer0. It is a matter of course that the recording layer information and the writing speed information can be separately recorded in a reserved area within disc information. And, identification information enabling to identify a type or kind of the disc information is recorded in a specific area of Nth byte, which is named ‘DI Type’ field, within the disc information. Moreover, a write strategy (WS) interoperating with the type of the corresponding disc information is recorded in another specific area, e.g., area named ‘Write Strategy parameters’ field as Lth˜111th bytes, within the disc information. Namely, it is identified whether the corresponding disc information is in ‘CLV’ mode or ‘CAV’ mode via ‘DI Type’ field, and the write strategy (WS) is recorded in a manner fitting the identified mode. For instance, if it is the CLV mode, a WS for one recording velocity is recorded only. If it is CAV mode, it is necessary to record a WS for one type recording velocity group (e.g., three kinds of linear velocities such as lx, 1.7×, and 2.4×). And, if the information identifying the disc information type is ‘0000 0000b’ for example, it means to define ‘CLV disc information (DI)’. If ‘0000 0001b’, it means to define ‘CAV disc information (DI). FIG. 5 shows an exemplary method of recording disc information in case of recording identification information for identifying a disc information type in Nth byte within the disc information like FIG. 4, in which one recording layer Layer0 is shown for convenience of explanation. And, it is a matter of course that the method can be applied in the same manner even if there exist more recording layers. The disc information of the present invention, as mentioned in the foregoing description, is information that a disc manufacturer records characteristics of a corresponding disc in a prerecorded area within the disc. A write strategy (WS) the disc has is defined so that a recording/reproducing apparatus (FIG. 12) can utilize it in the practical application of the recording/reproducing. Hence, in recording disc information, a disc manufacturer preferentially decides an applicable writing speed per recording layer and then records identification information indicating whether the decided writing speed corresponds to the CLV or CAV method in the Nth byte. Hence, the write strategy (WS) interworking with the identification information is identified according to a CLV or CAV mode to be recorded in Lth˜111th bytes. For instance, disc information for 1× speed of 1st recording layer is recorded in ‘00h’ as a disc information sequence, a disc information type means a CAV mode, and a write strategy (WS) interworks with it so that a CAV WS is selected to be recorded. Disc information for 2× speed of 1st recording layer is recorded in ‘01h’, a disc information type means a CLV mode, and a write strategy (WS) interworks with it so that a CLV WS is selected to be recorded. Disc information for 4× speed of 1st recording layer is recorded in ‘02h’, a disc information type means a CLV mode, and a write strategy (WS) interworks with it so that a CLV WS is selected to be recorded. Disc information for 8× speed of 1st recording layer is recorded in ‘03h’, a disc information type means a CAV mode, and a write strategy (WS) interworks with it so that a CAV WS is selected to be recorded. In this case, the CLV or CAV WS means one write strategy (WS) selected by a disc manufacturer. In case of CLV, the write strategy will be applied to one kind writing speed. In case of CAV, the write strategy will be applied to a plurality of writing speeds for one type writing speed or recording velocity group. FIG. 6 is a diagram of recording control information according to another embodiment of the present invention. Compared to the embodiment in FIG. 4, FIG. 6 shows that specific identification for CAV mode is subdivided to be applied to ‘DI Type’ field written in Nth byte within disc information. Namely, in case that corresponding disc information means CAV mode, this is subdivided to identify how many velocities are provided by a write strategy (WS). Hence, ‘DI Type’ field can be defined as follows. If ‘DI Type’ field recorded in Nth byte is ‘0000 0001b’, it means CAV mode and a write strategy (WS) recorded in Lth˜111th bytes is recorded to correspond to one kind of velocity only. If ‘DI Type’ field recorded in Nth byte is ‘0000 0010b’, it means CAV mode and a write strategy (WS) recorded in Lth˜111th bytes is recorded to correspond to two kinds of velocities. If ‘DI Type’ field recorded in Nth byte is ‘0000 0010b’, it means CAV mode and a write strategy (WS) recorded in Lth˜111th bytes is recorded to correspond to three kinds of velocities. Generally, in case of CAV mode, the corresponding disc information has a write strategy relating to three kinds of velocities. Yet, the above-explained definition of ‘DI Type’ field enables a disc manufacturer to avoid having difficulty in coping with various write strategies. And, the above-explained definition of ‘DI Type’ field enables a manufacturer of a disc recording/reproducing apparatus to develop an inexpensive product coping with one write strategy (WS) only. FIG. 7 is a diagram of recording control information according to a further embodiment of the present invention, in which information for identifying a type of disc information is recorded within disc information like the embodiment in FIG. 4 together with another information enabling to identify a type of write strategy (WS) finally used. Referring to FIG. 7, the information enabling to identify a write strategy (WS) type is to identify which one of a plurality of specified write strategies (WS) was selected to be used by a disc manufacturer, whereas the information for identifying a disc information type enables to identify whether corresponding disc information is in CLV mode or CAV mode. For instance, as mentioned in the foregoing description, various write strategy types, which can exist such as (n-1) WS, n/2 WS, etc., are defined as 1st WS WS-1, 2nd WS WS-2, . . . and Kth WS WS-K. And, the information identifying the write strategy type (named ‘WS Type’) selected by a disc manufacturer is recorded within disc information. This is explained by being compared to the embodiment in FIG. 4 as follows. First of all, ‘Write Strategy (WS) Type’ field is added to Pth byte of the embodiment in FIG. 4 so that Lth˜111th write strategy (WS) is recorded by interworking with a disc information type in Nth byte and a write strategy (WS) type in Pth byte. Namely, it can be defined as follows. If ‘0000 0000b’ is written in Pth byte, it means 1st WS WS-1. If ‘0000 0010b’ is written in Pth byte, it means 2nd WS WS-2. And, if ‘XXXX XXXXb’ is written in Pth byte, it means Kth WS WS-K. FIG. 8 is a diagram of recording a write strategy within control information according to the further embodiment of the present invention in FIG. 7, and FIG. 9 is a diagram of another example of recording a write strategy within control information according to the further embodiment of the present invention in FIG. 7. FIG. 8 shows that a disc manufacturer optionally records a specific write strategy (WS) for entire writing speeds in recording one of a plurality of write strategies (WS). Referring to FIG. 8, Nth byte of disc information indicates a disc information type, Pth byte of disc information indicates a write strategy (WS) type, and parameters associated with one write strategy (WS) decided by interworking with the Nth and Pth bytes are recorded in Lth˜111th bytes. For instance, disc information for 1× speed of 1st recording layer is recorded in ‘00h’ as a disc information sequence, a disc information type means a CAV mode, a write strategy (WS) type means 1st WS WS-1, and a write strategy (WS) interworks with them so that a CAV WS-1 is selected to be recorded. Disc information for 2× speed of 1st recording layer is recorded in ‘01h’, a disc information type means a CLV mode, a write strategy (WS) type means 1st WS WS-1, and a write strategy (WS) interworks with them so that a CLV WS-1 is selected to be recorded. Disc information for 4× speed of 1st recording layer is recorded in ‘02h’, a disc information type means a CLV mode, a write strategy (WS) type means 2nd WS WS-2, and a write strategy (WS) interworks with them so that a CLV WS-2 is selected to be recorded. Disc information for 8× speed of 1st recording layer is recorded in ‘03h’, a disc information type means a CAV mode, a write strategy (WS) type means 2nd WS WS-2, and a write strategy (WS) interworks with them so that a CAV WS-2 is selected to be recorded. FIG. 9 shows that one of a plurality of write strategies (WS) is recorded within disc information, in which a mandatory write strategy (WS) type is recorded for a specific specified writing speed (e.g., 1× speed) but a disc manufacturer optionally records a specific write strategy (WS) for the rest writing speeds. Hence, the method in FIG. 9 differs from the method in FIG. 8 in that a write strategy (WS) type is decided in a mandatory manner by putting limitation on disc manufacturer's options for a specific writing speed (1× speed). This enables a manufacturer of a disc recording/reproducing apparatus (FIG. 12) to design to manufacture inexpensive products coping with one write strategy (WS) type only. For instance, disc information for 1× speed of 1st recording layer is recorded in ‘00h’ as a disc information sequence, a disc information type means a CAV mode, a write strategy (WS) type means 1st WS WS-1, and a write strategy (WS) interworks with them so that a CAV WS-1 is selected in a mandatory manner to be recorded. Disc information for 2× speed of, 1st recording layer is recorded in ‘01h’, a disc information type means a CLV mode, a write strategy (WS) type means 1st WS WS-1, and a write strategy (WS) interworks with them so that a CLV WS-1 is selected to be recorded. Disc information for 4× speed of 1st recording layer is recorded in ‘02h’, a disc information type means a CLV mode, a write strategy (WS) type means 2nd WS WS-2, and a write strategy (WS) interworks with them so that a CLV WS-2 is selected to be recorded. Disc information for 8× speed of 1st recording layer is recorded in ‘03h’, a disc information type means a CAV mode, a write strategy (WS) type means 2nd WS WS-2, and a write strategy (WS) interworks with them so that a CAV WS-2 is selected to be recorded. FIG. 10 is a diagram of recording control information according to another further embodiment of the present invention, in which specific identification for CAV mode is subdivided to be applied to ‘DI Type’ field written in Nth byte within disc information and in which information designating a write strategy (WS) type is recorded as well. Referring to FIG. 10, in case that corresponding disc information means CAV mode, this is subdivided to identify how many velocities are provided by a write strategy (WS). Hence, ‘DI Type’ field can be defined as follows. If ‘DI Type’ field recorded in Nth byte is ‘0000 0001b’, it means CAV mode and a write strategy (WS) recorded in Lth˜111th bytes is recorded to correspond to one kind of velocity only. If ‘DI Type’ field recorded in Nth byte is ‘0000 0010b’, it means CAV mode and a write strategy (WS) recorded in Lth˜111th bytes is recorded to correspond to two kinds of velocities. If ‘DI Type’ field recorded in Nth byte is ‘0000 0011b’, it means CAV mode and a write strategy (WS) recorded in Lth˜111th bytes is recorded to correspond to three kinds of velocities. Moreover, ‘Write Strategy (WS) Type’ field is added to Pth byte within disc information so that Lth˜111th write strategy (WS) is recorded by interworking with a disc information type in Nth byte and a write strategy (WS) type in Pth byte. Namely, it can be defined as follows. If ‘0000 0000b’ is written in Pth byte, it means 1st WS WS-1. If ‘0000 0010b’ is written in Pth byte, it means 2nd WS WS-2. And, if ‘XXXX XXXXb’ is written in Pth byte, it means Kth WS WS-K. FIG. 11 is a diagram of recording a write strategy within control information according to another further embodiment of the present invention in FIG. 10. Referring to FIG. 11, ‘0000 0000b’ is written in ‘DI Type’ field of Nth byte to mean CLV mode. ‘0000 0001b’ is written in ‘Write Strategy (WS) Type’ field of Pth byte to mean 1st WS WS-1. 5th byte is ‘00h’ to mean 1× speed disc information of 1st recording layer. And, a specific write strategy (WS) interworking with the Nth and Pth bytes is written in Lth˜111th bytes within a disc. As it is a CLV mode, a write strategy (WS) for one kind of velocity is recorded. As it is 1st WS WS-1, parameters by ‘(n-1) WS’ type are defined for example. Accordingly, a disc manufacturer records an optimal value in a corresponding disc. If ‘DI Type’ field (Nth byte) is set to ‘0000 0001b’ to mean a CAV mode, or if ‘Write Strategy (WS) Type’ field is set to ‘0000 0010b’ to mean 2nd WS WS-2, it is apparent that write strategy (WS) parameters written in Lth˜111th bytes should be recorded as new contents different from the parameters specified in FIG. 11 or the values of the corresponding parameters. FIG. 12 is a block diagram of an optical disc recording/reproducing apparatus according to the present invention. Referring to FIG. 12, a recording/reproducing apparatus according to the present invention includes a recorder/reproducer 10 carrying out recording/reproducing on an optical disc and a control unit 20 controlling the recorder/reproducer 10. The control unit 20 gives a record or playback command for a specific area, and the recorder/reproducer 10 caries out the recording/reproducing on the specific area according to the command of the control unit 20. Specifically, the recorder/reproducer 10 includes an interface unit 12 performing communications with an external device, a pickup unit 11 directly recording data on the optical disc or reproducing the data, a data processor 13 receiving a playback signal from the pickup unit 11 to restore into a necessary signal value or modulating to deliver a signal to be recorded into a signal to be recorded on the optical disc, a servo unit 14 reading out a signal from the optical disc correctly or controlling the pickup unit 11 to record a signal on the optical disc correctly, a memory 15 temporarily storing management information including control information and data, and a microcomputer 16 responsible for controlling the above-described elements within the recorder/reproducer 10. A disc information recording process of an optical disc according to the present invention is explained in detail as follows. First of all, once an optical disc is loaded in the recording/reproducing apparatus, the entire disc management information within the disc is read out to be temporarily stored in the memory 15 of the recorder/reproducer 10. And, various kinds of the disc management information are utilized for the recording/reproducing of the optical disc. Specifically, the management information stored in the memory 15 includes disc information of the present invention. Hence, information for identifying a disc information type recorded within disc information, identification information for identifying a write strategy (WS), and write strategy parameter values interworking with them are read out to be temporarily stored in the memory 15. If intending to perform a recording on a specific area within the optical disc, the control unit 20 renders such an intent into a writing command and then delivers it to the recorder/reproducer 10 together with data for writing location information to be recorded. After receiving the writing command, the microcomputer 16 decides the corresponding writing speed applied to an area within the optical disc from the management information (specifically via disc information) stored in the memory 15 and then performs the writing command by finding optimal write power by referring to a write strategy (WS) corresponding to the decided writing speed. Accordingly, the present invention provides various methods of providing control information coping with higher writing speed in a high-density optical disc. Specifically, in recording a write strategy (WS) within disc information, CLV and CAV are separately recorded, whereby it is able to efficiently cope with the record/playback of the optical disc. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a method of recording control information on a recording medium, such as a recordable optical disc, and a method of recording data on a recording medium using the control information. 2. Discussion of the Related Art A high-density optical recording medium, known as HD-DVD, is widely used to record and store high-definition video data and high-quality audio data. The Blu-ray disc (hereinafter abbreviated BD) represents next-generation HD-DVD technology. Technological specifications are now being established for the global standardization of the Blu-ray disc, including standards for a write-once Blu-ray disc (BD-WO). Meanwhile, a rewritable Blu-ray disc, known as 1× speed BD-RE and now under discussed should be compatible with BD-RE discs expected to have higher writing speed, i.e., 2× speed BD-RE and beyond. BD-WO specifications for high writing speed are also in progress. Efficient solutions for coping with the high writing speed of a high-density optical disc are urgently needed, and the specifications established should ensure mutual compatibility.
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<SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, the present invention is directed to a method of recording control information in an optical disc that substantially obviates one or more problems due to limitations and disadvantages of the related art. An object of the present invention is to provide a new method of recording control information as specified information coping with high writing speed, in which information indicating a kind of control information is recorded within the control information as well as a write strategy interworking with the recorded information. Another object of the present invention is to define a new data structure configuring control information. Another object of the present invention is to provide a specified method of recording control information coping with high writing speed in a specific area within a disc, by which reciprocal compatibility is provided between the same based discs. A further object of the present invention is to provide a recording/reproducing method and apparatus thereof, by which real data is recorded/reproduced on/from an optical disc using the recorded control information. Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method of recording control information on a recording medium according to the present invention includes the steps of generating a control information associated with at least one or more recording layers and recording velocities, the control information including first information identifying a type of the corresponding control information, the information indicating whether the control information is used for CLV (constant linear velocity) or CAV(constant angular velocity), and a write strategy parameters associated with the type of the control information; and recording the control information on a specific area of the recording medium. In another aspect of the present invention, A data structure of a control information recorded on a recording medium or to be recorded/reproduced on/from the recording medium, characterized in that the control information associated with a specific recording layer and/or a specific recording velocity and the control information comprises write strategy information dependent on a type information indicating whether the control information is associated with CAV or CLV. In another aspect of the present invention, a recording medium includes at least one recording layer provided with a recordable area and a pre-recorded area, wherein a disc information is separately provided according to each recording velocity and/or each recording layer to the pre-recorded area and wherein an identification information identifying a type of the disc information therein and a write strategy information associated with the identification information therein are provided to the disc information. In another aspect of the present invention, An optical disc includes at least one or more recording layers, wherein a control information is provided according to each recording layer and/or each recording velocity, wherein an identification information identifying a type of the control information and a write strategy parameters associated with the identification information are recorded within the control information. In another aspect of the present invention, a method of recording data on a recording medium includes the steps of reading a plurality of control information separately recorded according to each recording velocity within a management area of the recording medium, checking an identification information identifying a control information type recorded within each control information, and performing a recording of data based on a write strategy information associated with a corresponding recording velocity from the identification information. In another aspect of the present invention, a method of recording data on a recording medium includes the steps of identifying a specific control information based on an identification information identifying a type of control information, wherein the control information associated with specific recording velocity and/or specific recording layer to provide a reference information for recording or reading of data, the identification information identifying whether the control information is used for CLV or CAV, and recording data using write strategy parameters included in the control information to be used for CLV or CAV as a result of identifying step. In another aspect of the present invention, an apparatus for recording data on a recording medium includes an optical pickup reading a plurality of control information associated with at least recording velocity within a management area of the recording medium; and a controller checking a control information type based on an identification information to identify whether the corresponding control information is used for CLV or CAV, reading a write strategy included in the corresponding control information as a result of the checking step, and performing the recording of data using the read write strategy. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
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20040706
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20121113
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20050113
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63353.0
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BERNARDI, BRENDA C
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RECORDING MEDIUM, METHOD OF CONFIGURING CONTROL INFORMATION THEREOF, RECORDING AND/OR REPRODUCING METHOD USING THE SAME, AND APPARATUS THEREOF
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,883,726
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ACCEPTED
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Apparatus for supporting a stator end winding
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An apparatus (10) for supporting a winding (7) on a stator (1), in particular on a generator stator in a power station. The winding (7) has an end winding (9) which is supported axially on the core (2) of the stator (1) via winding supports (11) of the supporting apparatus (10). The winding supports (11) are supported on the end winding (9) via a stressing device (22), at right angles to an envelope surface (21). In order to improve the axial position between the winding support (11) and the end winding (9) during operation of the stator (1), a coupling device (23) is provided which allows relative movements between the end winding (9) and the winding support (11) in the circumferential direction and at right angles to the envelope surface (21), and prevents such relative movements in an envelope line direction (30).
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1. An apparatus for supporting a winding on a stator, the stator including a core and at least one axial end face, the apparatus comprising: a winding having two or more winding bars having ends which pass axially out of the stator core to form an end winding which widens in the form of a funnel on the at least one axial end face of the stator core; two or more winding supports circumferentially distributedly arranged with respect to the end winding on said at least one axial end face and are supported axially on said at least one axial end face and essentially at right angles to the end winding; a stressing device, at least one of the winding supports being associated with the stressing device, the stressing device arranged between the end winding and said at least one winding support and producing a supporting force by which said at least one winding support is supported on the end winding via the stressing device; a coupling device, at least one of the winding supports being associated with the coupling device, the coupling device allowing relative movements between the end winding and said associated at least one winding support in the circumferential direction of the end winding and at right angles to an envelope surface of the end winding, the coupling device inhibiting relative movements in an envelope line direction of the end winding. 2. The supporting apparatus as claimed in claim 1, wherein the coupling device includes a coupling body arranged firmly on the end winding, and a recess formed on the associated at least one winding support; two mutually facing planar guide surfaces extending parallel to one another and in the circumferential direction, and at right angles to the envelope surface, the recess bounded in the envelope line direction by the two mutually facing planar guide surfaces; the coupling body projecting at right angles to the envelope surface into the recess and supported by supporting zones in the envelope line direction on the guide surfaces. 3. The supporting apparatus as claimed in claim 2, wherein the coupling device includes at least one threaded bolt and the coupling body includes a threaded opening, the bolt screwed into the threaded opening which extends in the envelope line direction in the coupling body; a threaded bolt end projecting out of the threaded opening, wherein one of the supporting zones is formed on said threaded bolt end. 4. The supporting apparatus as claimed in claim 3, wherein the threaded opening comprises a through opening; and further comprising a threaded bolt end projecting on each side of the threaded opening, one of the supporting zones being formed on each threaded bolt end. 5. The supporting apparatus as claimed in claim 4, further comprising: two threaded bolts screwed into the threaded opening including threaded bolt ends projecting out of the threaded opening on opposite sides; or a single threaded bolt screwed into the threaded opening including threaded bolt ends projecting out of the threaded opening on opposite sides. 6. The supporting apparatus as claimed in claim 3, wherein, at a threaded bolt end which projects out of the threaded opening, each threaded bolt includes an external polygonal shape suitable for the introduction of a screwing torque. 7. The supporting apparatus as claimed in claim 2, wherein the end winding has at least one outer bracing plate and at least one inner bracing plate, between which ends of the winding bars are braced; and wherein the coupling body is fixed on one of the at least one outer bracing plate. 8. The supporting apparatus as claimed in claim 2, further comprising: an interlocking coupling; and wherein the coupling body is attached to the end winding by the interlocking coupling. 9. The supporting apparatus as claimed in claim 2, wherein the stressing device includes a wedge positioned close to the core and a wedge positioned remote from the core, the wedges mounted on the end winding and on a respective winding support such that the wedges can move in the envelope line direction, and further comprising a tie rod that braces the wedges with respect to one another, the tie rod extending in the envelope line direction, the wedges driving a respective winding support and the end winding away from one another at right angles to the envelope surface; wherein the coupling body includes a through-opening extending in the envelope line direction; and wherein the tie rod passes through the through-opening. 10. The supporting apparatus as claimed in claim 9, further comprising a damping material on an inner face of the through-opening; and wherein the tie rod includes an outer face supported by the damping material. 11. The supporting apparatus as claimed in claim 9, wherein the through-opening contains a tube composed of a damping material through which tube the tie rod extends. 12. The supporting apparatus as claimed in claim 1, further comprising: at least one closed supporting ring extending in the circumferential direction; and wherein the winding supports are connected to one another and are supported radially on the outside by the at least one closed supporting ring. 13. The supporting apparatus as claimed in claim 1, further comprising: means for holding the supporting apparatus in an axially elastic manner on the end face of the core. 14. The supporting apparatus as claimed in claim 1, wherein the stator comprises a generator stator in a power station. 15. The supporting apparatus as claimed in claim 8, wherein the interlocking coupling comprises a dovetail coupling.
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This application claims priority under 35 U.S.C. § 119 to German application no. 103 30 523.8, filed Jul. 5, 2003, the entirety of which is incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supporting a winding on a stator, in particular on a generator stator in a power station. 2. Brief Description of the Related Art Normally, a stator, in particular a generator stator in a power station, has a core as well as a winding which has two or more winding bars. The ends of these winding bars are passed out of the core at at least one axial end face of the core of the stator, and are thus bent around and connected to one another such that they form an end winding on the end face of the core, which widens in the form of a funnel or in the form of a cone as the distance from the core increases. For operation of the stator, this end winding must be supported in the axial direction of the stator, that is to say axially, with tensile stress being applied to the core. Furthermore, the end winding must be loaded radially from the outside to the inside by means of prestressing. This stressing or support of the end winding is necessary in order to make it possible to absorb the electrodynamic forces which occur during operation. In some cases, the desired bracing of the winding and of the end winding is applied even during the manufacture of the stator. However, seating processes and the like may occur during operation of the stator which may have a disadvantageous effect on the stress acting on the winding and on the end winding. U.S. Pat. No. 5,798,595 discloses a supporting apparatus in which the end winding is braced and is radially supported with the aid of supporting rings. The supporting rings in this case extend in the circumferential direction and surround the outer face of the end winding. The end winding is in this case supported on the outside of these supporting rings at right angles to its envelope surface. These supporting rings allow a predetermined prestress to be applied to the end winding during the manufacture of the stator winding. However, this stress may decrease as a result of seating processes. In the case of the known supporting apparatus, the winding supports each have an associated damping device which operates with compression springs that are arranged between the respective winding support and the supporting rings. This results in a sprung bearing for the supporting rings on the winding supports. At the same time, the compression springs can produce axial bracing for the winding. However, the compression springs cannot provide additional radial bracing, or bracing at right angles to the envelope surface, of the end winding, since the supporting rings absorb the spring forces in this direction. U.S. Pat. No. 4,488,079 discloses a further supporting apparatus for an end winding, in which the end winding is stiffened with the aid of bracing plates, which are arranged radially on the outside of the end winding. The winding supports are then supported radially and at right angles to the envelope surface on the bracing plates of the end winding. SUMMARY OF THE INVENTION The invention is intended to overcome this problem. The invention relates to the problem of specifying an improved embodiment for supporting a stator winding or an end winding, which can maintain the desired stress or supporting effect better particularly during varying operating conditions. In the case of the supporting apparatus according to the invention, the stressing devices which are associated with the winding supports may introduce the desired prestressing into the end winding such that it is distributed around the circumference. The stressing devices may in this case be designed, for example with the aid of spring devices, directly such that they can compensate to a greater or lesser extent for seating processes or the like in the end winding, so that the desired bracing can essentially always be ensured even in changing conditions. The coupling device proposed according to the invention prevents relative movements between the end winding and the supporting apparatus or the respective winding support in an envelope line direction of the end winding, and in the process ensures that the winding supports are always in the same relative position with respect to the end winding, in terms of the envelope line direction. This is advantageous for introducing optimum supporting forces into the end winding. Furthermore, this positive coupling is particularly important for situations where the end winding is moving toward the core of the stator, as is the case, for example, while the stator winding is cooling down. During a movement such as this, the positive coupling via the at least one coupling device means that the winding supports and the supporting apparatus are likewise moved back against the end face of the core. In this case, it has been found that it is particularly important for correct operation of the supporting apparatus that the coupling device allows relative movements between the end winding and the respective winding support in the circumferential direction of the end winding as well as at right angles to the envelope surface of the end winding. This allows the end winding to twist or expand at right angles to the envelope surface without being impeded by the coupling devices. This avoids undesirable stresses between the winding supports and the end winding in the area of the coupling devices. In one particularly advantageous development, the coupling device may have a coupling body which is arranged fixed on the end winding, as well as a cut out which is formed on the respective winding support, and is bounded in the envelope line direction by two planar guide surfaces, which face one another and extend parallel to one another in the circumferential direction and at right angles to the envelope surface. In this case, the coupling body projects at right angles to the envelope surface into the cut out, and is supported by supporting zones in the envelope line direction on the guide surfaces. This configuration deliberately results in two degrees of freedom between the end winding and the respective winding support specifically for relative movements at right angles to the envelope surface and in the circumferential direction. In contrast to this, relative movements in the envelope line direction are prevented by the supporting surfaces which rest on the guide surfaces, that is to say by means of an interlock. The degrees of movement freedom between the end winding and the respective winding support are thus defined or predetermined exactly in the desired manner. In one development, the stressing device may have a wedge close to the core as well as a wedge remote from the core, which are mounted on the end winding and on the respective winding support such that they can move in the envelope line direction and which are braced with respect to one another by means of a tie rod, driving the respective winding support and the end winding away from one another at right angles to the envelope surface. A stressing device such as this results in the forces which are transmitted by means of the tie rod and are produced, for example, by means of a compression spring device being converted via the wedges into supporting forces, and amplified in the process, dependent on the wedge shape. This results on the one hand in a spring support which, on the other hand acts essentially in only one direction, specifically at right angles to the envelope surface, via the expediently guided wedges. In this development, the coupling body expediently contains a through-opening, which extends in the envelope line direction and through which the tie rod extends. This results on the one hand in the tie rod having a dual function, since it secures the coupling body on the end winding in an interlocking manner. Furthermore, this measure allows a particularly space-saving, compact construction. Assuming that it is appropriately supported in the radial direction, the end winding can be braced radially and axially, and in the envelope direction, with the aid of the stressing devices. The abovementioned configuration is used in one development such that the outer face of the tie rod is supported via a damping material on an inner face of the through-opening, in which case the through-opening may contain, in particular, a tube composed of the damping material, through which the tie rod extends. The proposed, damped support for the tie rod on the coupling body results in intensive oscillation damping for the tie rod during operation of the stator, thus increasing the fatigue life of the respective stressing device, and at the same time “smoothing” high-frequency disturbances that are superimposed on the supporting forces produced by the stressing device as a result of the vibration of the tie rod. Further important features and advantages of the invention can be found in the drawings and in the associated description of the figures with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS Preferred exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description, with the same reference symbols relating to the same, similar or functionally identical components. In the figures, in each case schematically: FIG. 1 shows a simplified axial section through a stator in the area of a supporting apparatus according to the invention, FIG. 2 shows a view as in FIG. 1, but illustrated enlarged, FIG. 3 shows a side view of a coupling body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring As can be seen from FIG. 1, a stator 1 (only part of which is illustrated), in particular a generator stator for a generator (which is not illustrated apart from this), which is used, for example, in order to generate electrical power in a power station, has a core 2 (which is likewise illustrated only partially) which is illustrated in FIG. 1 such that its longitudinal center axis runs essentially horizontally. In this case, the longitudinal center axis of the core 2 is not located on the surface of the drawing in FIG. 1, but, for illustrative purposes, is symbolized by a double-headed arrow 3, which runs parallel to the longitudinal center axis of the core 2 and thus represents the axial direction. The core 2 has an axial end face 4 which in this case is in the form of a pressure plate 5 on the core 2. Two such pressure plates 5, which are arranged at the two axial ends of the core 2, can be used to brace metal-laminate segments, which are arranged between them, form the core 2, but are not shown here, with respect to one another in the axial direction. Away from the surface of the drawing, the core 2 contains a number of longitudinal slots on its inner circumference, in which winding bars 6 of a winding 7 are accommodated. The ends 8 of these winding bars 8 are passed out of the core 2 in the axial direction 3 on the end face 4 of the core 2 and are bent around radially outwards and in the circumferential direction of the stator 1, thus that at the ends 8 of the winding bars 6 form an involute profile. The ends 8 of the winding bars 6 are in this case curved and, in particular, connected to one another, such that they form an end winding 9, which widens in the form of a funnel or in the form of a cone as the distance from the core 2 increases. In order that the winding 7 of the stator 1 can absorb the electrodynamic forces which occur during its operation, the winding 7 must be prestressed with relatively large forces in the axial direction 3. For this purpose, the end winding 9 must first of all be braced in the circumferential direction, in order to form a type of supporting buttress for introducing the axial forces into the axially extending winding bars 6. A supporting apparatus 10 according to the invention, and which has two or more winding supports 11, is used to produce this buttress-like bracing. In this case, these winding supports 11 are triangular or conical and are arranged distributed in the circumferential direction, in particular symmetrically, along the end face 4 of the core 2. In the case of the embodiment shown here, at least the winding support 11 that is described here may be (but need not be) supported axially on the end face 4 of the core 2 or on the core via at least one axially acting compression spring device 12. All of the winding supports 11 of the supporting apparatus 10 may expediently be axially supported on the core 2 via two or more such compression spring devices 12. In this case, it may in fact be worthwhile not supporting the individual compression spring devices 12 directly on the winding supports 11, but supporting them on a supporting ring 13 which is close to the core and which is itself supported axially on the winding supports 11. The supporting ring 13 which is close to the core extends in the circumferential direction and is closed. The supporting ring 13 close to the core is expediently firmly connected to each winding support 11, for example by means of a screw connection 14. It is obvious that the circumferential distribution of the winding supports 11 along the supporting ring 13 close to the core need not be designed to be identical to the circumferential distribution of the compression spring devices 12 along the supporting ring 13 close to the core. In particular, the circumferential position of the winding supports 11 and of the compression spring devices 12 may differ from one another. In the same way, the number of compression spring devices 12 need not be the same as the number of winding supports 11. However, it is important that, in principle, there is no need for such compression spring devices 12 for the supporting apparatus 10 according to the invention. In order that the supporting apparatus and the winding supports 11 as well as the supporting ring 13 close to the core 13 may be axially at a distance from the core 2, the winding supports 11 and the supporting apparatus 10 must be fitted to or held on the core 2 such that it or they can be lifted off it in the axial direction 3. This link to the core 2 is in this case provided with the aid of at least one leaf spring 15, which is attached on the one hand to the winding support 11 and on the other hand to the core 2. One leaf spring 15 such as this is expediently fitted on each side of the winding support 11. The leaf springs 15 may pull the supporting apparatus 10 and/or the respective winding support 11 against the core 2 and/or—depending on the installation—may also draw it or them away from the core 2. By way of example, the leaf springs 15 are prestressed against the core 2 during assembly, so that they are ideally in a neutral state during operation. The leaf springs 15 also prevent displacement or tilting of the respective winding support 11 in the circumferential direction. In this case, the traction forces of the leaf springs 15 are relatively small. The leaf spring 15 may, for example, have a first limb 16 which is attached to the winding support 11, as well as a second limb 17 which is attached to the end face of the core 2. The leaf spring 15 may be shaped between the link for the second limb 17 to the core 2 and the first limb 6 such that it produces the desired spring effect. By way of example, this particular section of the leaf spring 15 may have an Ω-shaped cross section. The compression spring device 12 may, for example in the case of the embodiment described here, have a piston 18 which is driven in the axial direction 3 by a stack of plate springs 19. Radially internally, the winding supports 11 are supported directly or indirectly on the end winding 9, to be precise in the direction 20 which runs essentially at right angles to an envelope surface 21 of the end winding 9. The support is thus essentially radial, but also has an axial component. At least the winding support 11 described here is supported indirectly on the end winding 9, to be precise via a stressing device 22. It is obvious that two or more of the winding supports 11, in particular all of them, are expediently supported on the end winding 9 via a respective stressing device 22 such as this. Furthermore, a coupling device 23 is formed between the end winding 9 and the winding support 11 described here. In this case as well, it is expedient for two or more of the winding supports 11, in particular all of them, to be associated with one such coupling device 23. The stressing device 22 and the coupling device 23 will be explained in more detail further below, with reference to FIG. 2. As has already been explained further above, all of the winding supports 11 are connected to one another via the supporting ring 13 close to the core. Furthermore, the winding supports 11 are supported in the radially outward direction on the supporting ring 13 close to the core. For this purpose, appropriately shaped supporting surfaces 24 interact, which are formed in a suitable manner on the supporting ring 13 close to the core and on the respective winding support 11. The closed supporting ring 13 close to the core means that the winding supports 11 cannot move away radially outwards. The embodiment described here also has a supporting ring 25 remote from the core, which likewise extends in the circumferential direction and is completely closed, and on which the winding supports 11 can likewise be supported on the outside in the radial direction. In a corresponding manner, suitable supporting surfaces 24 are once again formed between the winding supports 11 and the supporting ring 25 remote from the core. Furthermore, the supporting ring 25 remote from the core is also firmly connected to the winding supports 11, for example in each case via a suitable screw connection 26. The winding supports 11 are thus also supported radially on the outside at their end remote from the core. Overall, the winding supports 11 and the supporting rings 13, 25 form a supporting case 27 which is extremely stiff in the radial direction and is supported on the end winding 9 in order to brace the winding 7 of the stator 1. This supporting cage 27 on the one hand produces an intensive radial compression load on the end winding 9, oriented at right angles to the envelope surface 21, so that this forms a supporting buttress, which can be loaded in tension in the axial direction. The axial and radial bracing of the end winding 9 is in this case achieved with the aid of the stressing device 22. It is particularly important in this case for the supporting cage 27 to be held such that it can move in the axial direction 3 relative to the core 2, specifically via the leaf springs 15. This allows the supporting cage 27 to follow axial movements of the end winding 9 which the latter carries out relative to the core 2, for example as a consequence of thermal expansion effects. As is shown in FIG. 2, the stressing device 22 has a wedge 28 close to the core and a wedge 29 remote from the core. Both wedges 28, 29 are supported on a side facing the end winding 9 on a linear head rail 31 which extends parallel to an envelope line direction 30. In contrast, they are supported on a side facing the respective winding support 11 on a respective supporting rail 32 in the form of a ramp or wedge. The supporting rails 32 for the two wedges 28, 29, are in this case oriented such that they rise toward one another in the direction of the end winding 9. The wedges 28, 29 have sliding surfaces 33 which are complementary to the head rails 31 and to the supporting rails 32. The stressing device 22 also has a tie rod 34, which is anchored firmly in the wedge 28 close to the core. A pressure sleeve 35 is plugged onto the tie rod 34 and is supported on the wedge 29 remote from the core, on a side facing away from the wedge 28 close to the core. A relatively large compression force acts on the pressure sleeve 35 at the end facing away from the wedge 29 remote from the core by means of a compression spring device 36 which in this case is formed by a stack of plate springs. The compression spring device 36 is supported on a nut 37 on its side facing away from the pressure sleeve 35, and the nut 37 is screwed onto the tie rod 34. The wedge 29 remote from the core and the pressure sleeve 35 are arranged such that they can move along the tie rod 34. The tie rod 34 extends parallel to the envelope line direction 30. The compression spring device 36 braces the two wedges 28, 29, thus driving the two wedges 28, 29 toward one another. This bracing which acts in the envelope line direction 30, is transmitted via the wedges 28, 29 to the winding supports 11 and in the process is converted into a compression force or supporting force acting at right angles to the envelope surface 21, by means of which the winding supports 11 are supported on the end winding 9 via the wedges 28, 29. The wedge effect can in this case result in the force being amplified to a relatively major extent, so that comparatively large supporting forces can be achieved with relatively physically small compression spring devices 36, by means of which the supporting cage 27 braces the end winding 9. The stressing device 22 may in this case compensate for thermal expansion effects or seating phenomena in the end winding 9 in that the wedges 28, 29 are driven by the compression spring device 36 so that they move toward one another when the distance between the end winding 9 and the respective winding support 11 increases and such that they move apart from one another, against the compression force from the compression spring device 36, when the distance between the end winding 9 and the associated winding support 11 decreases. The coupling device 23 is now of major importance to the invention, and is designed such that it allows relative movements between the end winding 9 and the associated winding support 11 in the circumferential direction of the end winding 9 and at right angles to the envelope surface 21 of the end winding 9, while it prevents relative movements between the end winding 9 and the respective winding support 11 in the envelope line direction 30. In practice, it has been found that coupling such as this makes it possible on the one hand to prevent undesirable bracing between the individual winding supports 11 and the end winding 9 in the circumferential direction. On the other hand, the capability to move at right angles to the envelope surface 21 ensures that the stressing device 22 operates correctly. Furthermore, the positive coupling acting in the envelope line direction 30 between the end winding 9 and the winding support 11 results in the supporting cage 27 and the end winding 9 always being positioned in the same relative position with respect to one another, with reference to the axial direction 3. This makes it possible to ensure that the supporting cage 27 operates optimally and correctly. The coupling device 23 on the one hand makes it possible to ensure that the supporting cage 27 can follow the end winding 9 when it moves away from the core 2 as a result of thermal expansion of the winding 7 on the stator 1. On the other hand, the positive coupling by means of the coupling device 23 also ensures that the supporting cage 27 is moved back again when the end winding 9 moves back toward the core 2 as the winding 7 cools down. This configuration ensures that relative movements between the end winding 9 and core 2 of the stator 1 have no influence, or only a minor influence, on the bracing of the end winding 9. In the case of the preferred embodiment described here, the coupling device 23 comprises a coupling body 38 as well as a recess 39. The recess 39 is formed on a lower face of the respective winding support 11, facing the end winding 9. The recess 39 has two guide surfaces 40, which bound the recess 39 in the envelope line direction 30, face one another and are planar. The planar guide surfaces 40 in this case extend parallel to one another, at right angles to the envelope surface 21, and in the circumferential direction. The coupling body 38 is arranged in a fixed position relative to the end winding 9, projects from the end winding 9 at right angles to the envelope surface 21, and projects into the recess 39 in this direction 20. Within the recess 39, the coupling body 38 is supported via supporting zones 41 on the guide surfaces 40 in the envelope line direction 30. This results in an interlocking support between the coupling body 38 and the recess 39. Since the guide surfaces 40 are formed on the winding support 11, this results in an interlocking coupling between the winding support 11 and the end winding 9. In the preferred embodiment described here, the coupling body 38 forms a separate component, which is anchored on the end winding 9. For this purpose, the end winding 9 has a component 42 which is firmly connected to the ends 8 of the winding bars 6. This component is expediently an outer bracing plate 42, which bounds the end winding 9 radially on the outside and which is normally braced by means of an inner bracing plate (which is not shown) and is arranged radially inwards on the end winding 9, with the outer and inner bracing plates clamping those ends of the winding bars 6 which are located in between them. A central bracing plate 54, which additionally stiffens the braced end winding 9, can expediently be arranged radially between the ends 8 of the winding bars 6. The coupling body 38 is accordingly expediently attached to one of the outer bracing plates 42. An interlocking coupling 53, in particular a dovetail coupling, can be provided in order to anchor the coupling body 38 on the end winding 9, and in this case on the outer bracing plate 42. This configuration on the one hand allows particularly large forces to be transmitted. On the other hand, this makes it easier to install the coupling body 38. Furthermore, an interlocking coupling 44 such as this, in particular by means of a dovetail coupling such as this, allows forces to be transmitted comparatively uniformly between the coupling body 38 and the end winding 9 or the bracing plate 42, thus making it possible to avoid stress peaks. Although, in the case of the embodiment described here, the coupling body 38 is in the form of a separate or separable component, in another embodiment it may also in principle be permanently connected to the end winding 9 or to the bracing plate 42, for example, by means of a welded joint. It is likewise possible to form the coupling body 38 integrally on a corresponding component, for example the outer bracing plate 42, of the end winding 9. In the embodiment described here, the supporting zones 41 are not formed directly on the coupling body 38 but in each case on a threaded bolt end 43 of a threaded bolt 44, with the respective threaded bolt 44 being screwed into a complementary threaded opening 45 which is formed in the coupling body 38. The threaded opening 45 is in this case oriented parallel to the envelope line direction 30. The threaded bolts 44 accordingly also extend in the envelope line direction 30. The threaded bolt ends 43 project out of the threaded opening 45 beyond the coupling body 38 at both of its ends, with respect to the envelope line direction 30. The supporting zones 41 are expediently in the form of planar surfaces, in order to reduce the load per unit area between the supporting zones 41 and the guide surfaces 40. As an alternative to two individual threaded bolts 44, it is possible in another embodiment to provide one continuous threaded bolt 44 as well, which projects out of the threaded opening 45 at both ends 43 of the threaded bolt, and in each case has a supporting zone 41. The threaded opening 45 is in this case expediently in the form of a through-opening. Furthermore, it is also possible to design the coupling body 38 with more than one threaded opening 45, which are then fitted with one or with two threaded bolts 44 in a corresponding manner. The threaded bolts 44 are provided at each of their threaded bolt ends 43 with an external polygonal shape 46, which allows a torque to be applied to the respective threaded bolt 44 by means of a suitable tool. The torque is in this case used to produce a screwing movement. Firstly, this makes it possible optimally adjust the relative position of the coupling body 38 within the recess 39. If two individual threaded bolts 44 are used, it is also possible to compensate for manufacturing tolerances. For example, the threaded bolts 44 are braced with a predetermined torque against the guide surfaces 40. FIGS. 2 and 3 show a preferred embodiment of the coupling body 38 which is equipped with a through-opening 47. In the assembled state, this through-opening 47 extends parallel to the envelope line direction 30. The positions of the coupling body 38 and of the stressing device 22 are expediently now matched to one another such that the tie rod 34 passes through the coupling body 38 in the through-opening 47. The coupling body 38 is thus fixed in a captive manner on the end winding 9 when the stressing device 22 is installed. Damping material 50 is now advantageously arranged radially between an outer face 48 of the tie rod 34 and an inner face 49 of the through-opening 47. In this case, this is designed such that the tie rod 34 is supported on the coupling body 38 via the damping material 50. This makes it possible to damp vibration and oscillations, which the tie rod 34 is subject to during operation of the stator 1. This improves the correct operation of the stressing device 22. A tube 51 is expediently inserted into the through-opening 47, which tube 51 is composed of the damping material 50, and through which the tie rod 34 is then passed. The tube 51 may expediently be attached to the inner face 49 of the through-opening 47, for example by overmolding, by surface welding or vulcanization. The damping material 50 is expediently in the form of a rubber or a plastic, in particular based on silicone. The other components which interact with one another, in particular the outer bracing plate 42, the coupling body 38, the threaded bolts 44 and the winding support 11, are expediently formed from a high tensile-strength steel, for example of the HGW type. A gap 52 remains between the coupling body 38 and the recess 39 at right angles to the envelope surface 21, and is sufficiently large that there can be no direct contact between the winding support 11 and the coupling body 38 in this direction 20 as a result of any tolerable relative movements between the end winding 9 and the winding support 11. The proposed interlocking coupling 53, that is to say in this case the dovetail coupling, is in this case aligned tangentially with respect to the envelope surface 21, so that the coupling body 38 can be plugged onto the outer bracing plate 42 in the direction of a tangent. For this purpose, the stressing device 22 is disassembled to a sufficient extent that the tie rod 34 can be removed. It is advantageous in this case that the stressing device 22 need not be removed completely in order to assemble and to disassemble the coupling device 23. During the manufacture of the winding 7 of the stator 1, the insulation on the individual winding rods 6 is jointly polymerized. During this polymerization process, it is expedient even at this stage to brace the end winding 9 radially with the aid of the supporting cage 27. The individual winding bars 6 can then still move relative to one another during the polymerization process, thus dissipating any internal stresses. It is advantageous for the coupling device 23 to have not yet been activated during this polymerization process. For example, the coupling body 38 has not yet been installed during the polymerization of the winding 7. This allows relative movements in the envelope line direction 30 between the winding supports 11 and the end winding 9 for the polymerization process. List Of Reference Symbols 1 Stator 2 Core 3 Axial direction 4 End face of 2 5 Pressure plate 6 Winding bar 7 Winding on 1 8 End of 6 9 End winding 10 Supporting apparatus 11 Winding support 12 Compression spring device 13 Supporting ring close to the core 14 Screw connection 15 Leaf spring 16 First limb of 15 17 Second limb of 15 18 Piston 19 Stack of plate springs 20 Direction at right angles to 21 21 Envelope surface of 9 22 Stressing device 23 Coupling device 24 Supporting surface 25 Supporting ring remote from the core 26 Screw connection 27 Supporting cage 28 Wedge close to the core 29 Wedge remote from the core 30 Envelope line direction 31 Head rail 32 Supporting rail 33 Sliding surface 34 Tie rod 35 Pressure sleeve 36 Compression spring device 37 Nut 38 Coupling body 39 Recess 40 Guide surface 41 Supporting zone 42 Component of 9/outer bracing plate 43 Threaded bolt end 44 Threaded bolt 45 Threaded opening 46 External polygonal shape 47 Through-opening 48 Outer face of 34 49 Inner face of 47 50 Damping material 51 Tube 52 Gap 53 Interlocking coupling/dovetail coupling 54 Bracing plate, central While the invention has been described in detail with reference to preferred embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention. Each of the aforementioned documents is incorporated by reference herein in its entirety.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to an apparatus for supporting a winding on a stator, in particular on a generator stator in a power station. 2. Brief Description of the Related Art Normally, a stator, in particular a generator stator in a power station, has a core as well as a winding which has two or more winding bars. The ends of these winding bars are passed out of the core at at least one axial end face of the core of the stator, and are thus bent around and connected to one another such that they form an end winding on the end face of the core, which widens in the form of a funnel or in the form of a cone as the distance from the core increases. For operation of the stator, this end winding must be supported in the axial direction of the stator, that is to say axially, with tensile stress being applied to the core. Furthermore, the end winding must be loaded radially from the outside to the inside by means of prestressing. This stressing or support of the end winding is necessary in order to make it possible to absorb the electrodynamic forces which occur during operation. In some cases, the desired bracing of the winding and of the end winding is applied even during the manufacture of the stator. However, seating processes and the like may occur during operation of the stator which may have a disadvantageous effect on the stress acting on the winding and on the end winding. U.S. Pat. No. 5,798,595 discloses a supporting apparatus in which the end winding is braced and is radially supported with the aid of supporting rings. The supporting rings in this case extend in the circumferential direction and surround the outer face of the end winding. The end winding is in this case supported on the outside of these supporting rings at right angles to its envelope surface. These supporting rings allow a predetermined prestress to be applied to the end winding during the manufacture of the stator winding. However, this stress may decrease as a result of seating processes. In the case of the known supporting apparatus, the winding supports each have an associated damping device which operates with compression springs that are arranged between the respective winding support and the supporting rings. This results in a sprung bearing for the supporting rings on the winding supports. At the same time, the compression springs can produce axial bracing for the winding. However, the compression springs cannot provide additional radial bracing, or bracing at right angles to the envelope surface, of the end winding, since the supporting rings absorb the spring forces in this direction. U.S. Pat. No. 4,488,079 discloses a further supporting apparatus for an end winding, in which the end winding is stiffened with the aid of bracing plates, which are arranged radially on the outside of the end winding. The winding supports are then supported radially and at right angles to the envelope surface on the bracing plates of the end winding.
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<SOH> SUMMARY OF THE INVENTION <EOH>The invention is intended to overcome this problem. The invention relates to the problem of specifying an improved embodiment for supporting a stator winding or an end winding, which can maintain the desired stress or supporting effect better particularly during varying operating conditions. In the case of the supporting apparatus according to the invention, the stressing devices which are associated with the winding supports may introduce the desired prestressing into the end winding such that it is distributed around the circumference. The stressing devices may in this case be designed, for example with the aid of spring devices, directly such that they can compensate to a greater or lesser extent for seating processes or the like in the end winding, so that the desired bracing can essentially always be ensured even in changing conditions. The coupling device proposed according to the invention prevents relative movements between the end winding and the supporting apparatus or the respective winding support in an envelope line direction of the end winding, and in the process ensures that the winding supports are always in the same relative position with respect to the end winding, in terms of the envelope line direction. This is advantageous for introducing optimum supporting forces into the end winding. Furthermore, this positive coupling is particularly important for situations where the end winding is moving toward the core of the stator, as is the case, for example, while the stator winding is cooling down. During a movement such as this, the positive coupling via the at least one coupling device means that the winding supports and the supporting apparatus are likewise moved back against the end face of the core. In this case, it has been found that it is particularly important for correct operation of the supporting apparatus that the coupling device allows relative movements between the end winding and the respective winding support in the circumferential direction of the end winding as well as at right angles to the envelope surface of the end winding. This allows the end winding to twist or expand at right angles to the envelope surface without being impeded by the coupling devices. This avoids undesirable stresses between the winding supports and the end winding in the area of the coupling devices. In one particularly advantageous development, the coupling device may have a coupling body which is arranged fixed on the end winding, as well as a cut out which is formed on the respective winding support, and is bounded in the envelope line direction by two planar guide surfaces, which face one another and extend parallel to one another in the circumferential direction and at right angles to the envelope surface. In this case, the coupling body projects at right angles to the envelope surface into the cut out, and is supported by supporting zones in the envelope line direction on the guide surfaces. This configuration deliberately results in two degrees of freedom between the end winding and the respective winding support specifically for relative movements at right angles to the envelope surface and in the circumferential direction. In contrast to this, relative movements in the envelope line direction are prevented by the supporting surfaces which rest on the guide surfaces, that is to say by means of an interlock. The degrees of movement freedom between the end winding and the respective winding support are thus defined or predetermined exactly in the desired manner. In one development, the stressing device may have a wedge close to the core as well as a wedge remote from the core, which are mounted on the end winding and on the respective winding support such that they can move in the envelope line direction and which are braced with respect to one another by means of a tie rod, driving the respective winding support and the end winding away from one another at right angles to the envelope surface. A stressing device such as this results in the forces which are transmitted by means of the tie rod and are produced, for example, by means of a compression spring device being converted via the wedges into supporting forces, and amplified in the process, dependent on the wedge shape. This results on the one hand in a spring support which, on the other hand acts essentially in only one direction, specifically at right angles to the envelope surface, via the expediently guided wedges. In this development, the coupling body expediently contains a through-opening, which extends in the envelope line direction and through which the tie rod extends. This results on the one hand in the tie rod having a dual function, since it secures the coupling body on the end winding in an interlocking manner. Furthermore, this measure allows a particularly space-saving, compact construction. Assuming that it is appropriately supported in the radial direction, the end winding can be braced radially and axially, and in the envelope direction, with the aid of the stressing devices. The abovementioned configuration is used in one development such that the outer face of the tie rod is supported via a damping material on an inner face of the through-opening, in which case the through-opening may contain, in particular, a tube composed of the damping material, through which the tie rod extends. The proposed, damped support for the tie rod on the coupling body results in intensive oscillation damping for the tie rod during operation of the stator, thus increasing the fatigue life of the respective stressing device, and at the same time “smoothing” high-frequency disturbances that are superimposed on the supporting forces produced by the stressing device as a result of the vibration of the tie rod. Further important features and advantages of the invention can be found in the drawings and in the associated description of the figures with reference to the drawings.
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20040706
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20051115
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20050210
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86435.0
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MULLINS, BURTON S
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APPARATUS FOR SUPPORTING A STATOR END WINDING
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,883,783
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ACCEPTED
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Method and device for monitoring the validity of at least one parameter which is calculated by an anemometeric unit of an aircraft
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Method and device for monitoring the validity of at least one parameter which is calculated by an anemometeric unit of an aircraft. The device (1) includes means (13) for taking into account n first data, each dependent on said parameter being monitored, n being greater than or equal to 1, means (15) for taking into account p second data, p being greater than or equal to 2, each of which depends on at least one value obtained from at least one data source (Si) external to said anemometeric unit (2), means (18) for calculating, for each of the second data, a difference between this second datum and a first datum of the same type, means (21) for comparing the absolute value of each of said differences with a threshold value, and means (23) for deducing from said comparisons that said parameter is invalid if the absolute values of at least two of the various differences are greater than the corresponding threshold values.
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1. A method for monitoring the validity of at least one parameter which is calculated by an anemometeric unit (2) of an aircraft, wherein: a) a number n of first data are taken into account, each dependent on said parameter which is being monitored, n being an integer greater than or equal to 1; b) a plurality of p second data are taken into account, p being an integer greater than or equal to 2, each of said p second data being of the same type as one of said n first data and dependent on at least one value obtained from at least one data source (Si) which is external to said anemometeric unit (2), the various data sources (Si) furthermore being separate from one another; c) for each of said p second data, a difference is calculated between this second datum and a first datum of the same type; d) the absolute value of each of the differences calculated in this way is compared with a predetermined threshold value, in each case dependent on the data type corresponding to said difference; and e) the following are deduced from said comparisons: that said parameter is invalid if the absolute values of at least two of said various differences are greater than the corresponding predetermined threshold values; and that said parameter is valid otherwise. 2. The method as of claim 1, wherein at least one of said first data is calculated from the parameter which is being monitored. 3. The method as claimed in claim 1, wherein at least one of said first data corresponds to the parameter which is being monitored. 4. The method as claimed in claim 1, wherein at least one of said second data is calculated from said value obtained from a data source (Si). 5. The method as claimed in claim 1, wherein at least one of said second data corresponds to said value obtained from a data source (Si). 6. The method as claimed in claim 1, wherein, when at least two parameters are being monitored simultaneously, at least one of said first data depends simultaneously on said two parameters. 7. The method as claimed in claim 1, wherein at least one of said following parameters calculated by the anemometeric unit (2) is monitored: the total pressure; the static pressure; and the total temperature. 8. The method as claimed in claim 7, wherein said first data include at least one of the following data: a barometric altitude, this being calculated from the static pressure which is being monitored; and a velocity of the aircraft with respect to the air, this being calculated from the static and total pressures which are being monitored. 9. The method as claimed in claim 1, wherein at least one of said second data, which depend on values obtained from data sources (Si) external to the anemometeric unit (2), corresponds to at least one of the following values: an altitude value provided by a satellite positioning system; a total pressure value measured by a probe associated with at least one engine of the aircraft; a static pressure value measured by a probe associated with at least one engine of the aircraft; a total temperature value measured by a probe associated with at least one engine of the aircraft; a velocity value provided by a velocity estimation means; a static pressure value measured by a multifunctional probe; a static pressure value measured by a standby instrument; and a total pressure value measured by a standby instrument. 10. The method as claimed in claim 1, wherein the following differences are calculated in step c) in order to monitor the static pressured calculated by the anemometeric unit (2): the difference between a barometric altitude, calculated from said static pressure being monitored, and an altitude value provided by a satellite positioning system; the difference between a barometric altitude, calculated from said static pressure being monitored, and an altitude calculated from a static pressure value measured by a standby instrument; the difference between said static pressure being monitored and a static pressure value measured by a probe associated with an engine of the aircraft; the difference between said static pressure being monitored and a static pressure value measured by a multifunctional probe; and the difference between a velocity of the aircraft with respect to the air, calculated from said static pressure being monitored, and a velocity value provided by a velocity estimation means. 11. The method as claimed in claim 1, wherein the following differences are calculated in step c) in order to monitor the total pressure calculated by the anemometeric unit (2): the difference between said total pressure being monitored and a total pressure value measured by a probe associated with an engine of the aircraft; the difference between a velocity of the aircraft with respect to the air, calculated from said total pressure being monitored, and a velocity value provided by a velocity estimation means; and the difference between a velocity of the aircraft with respect to the air, calculated from said total pressure being monitored, and a velocity calculated from a total pressure value measured by a standby instrument. 12. The method as claimed in claim 1, wherein the following differences are calculated in step c) in order to monitor the total temperature calculated by the anemometeric unit (2): the difference between a barometric altitude, corrected with the aid of said total temperature being monitored, and an altitude value provided by a satellite positioning system; the difference between said total temperature being monitored and a total temperature value measured by a probe associated with an engine of the aircraft; and the difference between a velocity of the aircraft with respect to the air, calculated from said total temperature being monitored, and a velocity value provided by a velocity estimation means. 13. The method as claimed in claim 1 for an aircraft provided with q engines, q being an integer greater than or equal to 3, wherein the values measured by probes associated with said q engines are taken into account and the corresponding differences are calculated, and wherein a difference is considered to be abnormal only if it is abnormal with respect to the measured values relating to at least three of said q engines. 14. The method as claimed in claim 1 for an aircraft provided with two engines, wherein the values measured by probes associated with said two engines are taken into account and the corresponding differences are calculated, wherein the differences with respect to the measured values relating to said two engines are considered in each case, and wherein said differences are no longer taken into account in the event of a malfunction by one of said two engines. 15. The method as claimed in claim 1, wherein the monitoring of the validity of said parameter is disabled when the aircraft is in at least one particular flight phase. 16. A device for monitoring the validity of at least one parameter which is calculated by an anemometeric unit (2) of an aircraft, which includes: means (13) for taking into account at least a number n of first data, each dependent on said parameter which is being monitored, n being an integer greater than or equal to 1; means (15) for taking into account a plurality of p second data, p being an integer greater than or equal to 2, each of said p second data being of the same type as one of said n first data and dependent on at least one value obtained from at least one data source (Si) which is external to said anemometeric unit (2), the various data sources (Si) furthermore being separate from one another; means (18) for calculating, for each of said p second data, a difference between this second datum and a first datum of the same type; means (21) for comparing the absolute value of each of the differences calculated in this way with a predetermined threshold value, dependent on the data type corresponding to said difference; and means (23) for deducing from said comparisons: that said parameter is invalid if the absolute values of at least two of said various differences are greater than the corresponding predetermined threshold values; and that said parameter is valid otherwise. 17. A system for monitoring the validity of at least one parameter which is calculated by an anemometeric unit (2) of an aircraft, which includes at least: the device (1) specified in claim 16; said anemometeric unit (2); and said set (16) of data sources (Si) external to said anemometeric unit (2). 18. An aircraft, which comprises a device (1) capable of carrying out the method as specified in claim 1. 19. An aircraft, which comprises a device (1) as specified in claim 16.
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The present invention relates to a method and a device for monitoring the validity of at least one parameter which is calculated by an anemometeric unit of an aircraft. The parameters which are suitable for being monitored in the scope of the present invention, and which are calculated by an anemometeric unit, are in particular the total pressure Pt, the static pressure Ps and the total temperature TAT, which are important parameters for piloting the aircraft. In order to be valid, these parameters Ps, Pt, TAT must have at least a predetermined level of reliability. It is known that most modern airplanes include at least one anemometeric unit for determining the values of information such as the altitude of the aircraft or its velocity, which are used when piloting. For reasons of operational safety, airplanes generally include two or three anemometeric units. In order to calculate the aforementioned parameters, each anemometeric unit acquires data coming from one or more pressure sensors. Usually, each of said pressure sensors is located inside the fuselage of the airplane and is connected by a tube to a probe arranged passing through the surface of said fuselage. This tube is generally connected to the associated pressure sensor by means of a pneumatic connector, allowing it to be disconnected and reconnected easily. It is known that human errors, in particular during maintenance operations of the airplane, may cause malfunction of one or more of the pressure sensors of such an anemometeric unit. For example, the personnel tasked with performing an operation of washing the airplane often stick a piece of adhesive tape on each of the probes of the anemometeric unit, in order to prevent water from entering the tube during said wash. If they forget to remove one of said pieces of adhesive tape after the wash, the corresponding pressure sensor will be inoperative during the next flight of the airplane, since it will not be able to measure the pressure of the air outside the fuselage. It will in fact measure the pressure of the air in the tube, which is closed by the piece of adhesive tape at its end next to the probe. Another example of malfunction relates to the case when maintenance personnel disconnect the tube and the pressure sensor at an appropriate connector, for example in order to clean the inside of this tube. If they forget to reconnect the tube to the pressure sensor after having carried out the maintenance operation, said pressure sensor will also be inoperative since it will measure the pressure of the air inside the fuselage, instead of measuring the pressure of the air outside the fuselage. Another case of malfunction of a pressure sensor which may arise during the flight of the aircraft, relates to the case of said probes (for example the “Pitot” tube) icing up, which can prevent correct operation of said pressure sensor. No known solution makes it possible to detect the validity defect of an aforementioned parameter of the aircraft due to this last malfunction. It is an object of the present invention to overcome these drawbacks. It relates to a method for monitoring the validity of at least one parameter which is calculated by an anemometeric unit of an aircraft, and for detecting any anomaly of such a parameter rapidly and reliably, and at a low cost. To that end, said method is noteworthy according to the invention in that: a) a number n of first data are taken into account, each dependent on said parameter which is being monitored, n being an integer greater than or equal to 1; b) a plurality of p second data are taken into account, p being an integer greater than or equal to 2, each of said p second data being of the same type as one of said n first data and dependent on at least one value obtained from at least one data source which is external to said anemometeric unit, the various data sources furthermore being separate from one another; c) for each of said p second data, a difference is calculated between this second datum and a first datum of the same type; d) the absolute value of each of the differences calculated in this way is compared with a predetermined threshold value, in each case dependent on the data type corresponding to said difference; and e) the following are deduced from said comparisons: that said parameter is invalid if the absolute values of at least two of said various differences are greater than the corresponding predetermined threshold values; and that said parameter is valid otherwise By virtue of the invention, it is thus possible to rapidly and reliably determine any anomaly (or invalidity) of a parameter calculated by an anemometeric unit. The present invention therefore makes it possible to monitor at least one parameter Pt, Ps and/or TAT of an anemometeric unit of an aircraft, which requires a high level of reliability, from values which are obtained from data sources external to said anemometeric unit and whose level of reliability may be lower than that of the parameter which is being monitored, owing to the use of at least two separate external data sources. According to the invention: said first data may be calculated from the parameter which is being monitored, or may quite simply correspond to this parameter; and second data may be calculated from the value obtained from an external data source, or may quite simply correspond to this value. When at least two parameters are being monitored simultaneously, at least one of said first data advantageously depends simultaneously on said two parameters. In a preferred embodiment, said first data include at least one of the following data: a barometric altitude, this being calculated from the static pressure which is being monitored; and a velocity of the aircraft with respect to the air, this being calculated from the static and total pressures which are being monitored. Furthermore, at least one of said second data, which depend on values obtained from data sources external to the anemometeric unit, advantageously corresponds to at least one of the following values: an altitude value provided by a satellite positioning system; a total pressure value measured by a probe associated with at least one engine of the aircraft; a static pressure value measured by a probe associated with at least one engine of the aircraft; a total temperature value measured by a probe associated with at least one engine of the aircraft; a velocity value provided by a velocity estimation means; a static pressure value measured by a multifunctional probe; a static pressure value measured by a standby instrument; and a total pressure value measured by a standby instrument. The following differences are advantageously calculated in step c) in order to monitor the static pressured calculated by the anemometeric unit: the difference between a barometric altitude, calculated from said static pressure being monitored, and an altitude value provided by a satellite positioning system; the difference between a barometric altitude, calculated from said static pressure being monitored, and an altitude calculated from a static pressure value measured by a standby instrument; the difference between said static pressure being monitored and a static pressure value measured by a probe associated with an engine of the aircraft; the difference between said static pressure being monitored and a static pressure value measured by a multifunctional probe; and the difference between a velocity of the aircraft with respect to the air, calculated from said static pressure being monitored, and a velocity value provided by a velocity estimation means. Furthermore, the following differences are advantageously calculated in step c) in order to monitor the total pressured calculated by the anemometeric unit: the difference between said total pressure being monitored and a total pressure value measured by a probe associated with an engine of the aircraft; the difference between a velocity of the aircraft with respect to the air, calculated from said total pressure being monitored, and a velocity value provided by a velocity estimation means; and the difference between a velocity of the aircraft with respect to the air, calculated from said total pressure being monitored, and a velocity calculated from a total pressure value measured by a standby instrument. Furthermore, the following differences are advantageously calculated in step c) in order to monitor the total temperature calculated by the anemometeric unit: the difference between a barometric altitude, corrected with the aid of said total temperature being monitored, and an altitude value provided by a satellite positioning system; the difference between said total temperature being monitored and a total temperature value measured by a probe associated with an engine of the aircraft; and the difference between a velocity of the aircraft with respect to the air, calculated from said total temperature being monitored, and a velocity value provided by a velocity estimation means. In a particular embodiment applied to an aircraft provided with q engines, q being an integer greater than or equal to 3, the values measured by probes associated with said q engines are taken into account and the corresponding differences are calculated, and a difference is considered to be abnormal only if it is abnormal with respect to the measured values relating to at least three of said q engines. This makes it possible to avoid prematurely considering a monitored parameter to be invalid (abnormal difference) in the event of a malfunction of one of the engines of the airplane, leading to a malfunction of the probe or probes associated with this engine. In another embodiment applied to an aircraft provided with two engines, the values measured by probes associated with said two engines are taken into account and the corresponding differences are calculated, the differences with respect to the measured values relating to said two engines are considered in each case, and said differences are no longer taken into account in the event of a malfunction by one of said two engines. Furthermore, the monitoring of the validity of said parameter is advantageously disabled when the aircraft is in at least one particular flight phase, such as take-off or landing, and when it is passing through turbulence zones. This allows this monitoring to be made more robust by preventing a monitored parameter from prematurely being considered to be invalid. The present invention also relates to a device for monitoring the validity of at least one parameter which is calculated by an anemometeric unit of an aircraft, in particular a transport aircraft. According to the invention said device is noteworthy in that it includes: means for taking into account at least a number n of first data, each dependent on said parameter which is being monitored, n being an integer greater than or equal to 1; means for taking into account a plurality of p second data, p being an integer greater than or equal to 2, each of said p second data being of the same type as one of said n first data and dependent on at least one value obtained from at least one data source which is external to said anemometeric unit, the various data sources furthermore being separate from one another; means for calculating, for each of said p second data, a difference between this second datum and a first datum of the same type; means for comparing the absolute value of each of the differences calculated in this way with a predetermined threshold value, dependent on the data type corresponding to said difference; and means for deducing from said comparisons: that said parameter is invalid if the absolute values of at least two of said various differences are greater than the corresponding predetermined threshold values; and that said parameter is valid otherwise. The figures of the appended drawing will clearly show how the invention may be implemented. In these figures, identical references denote similar elements. FIG. 1 schematically illustrates a system according to the invention, applied to an aircraft (partially represented). FIG. 2 is the block diagram of a system according to the invention. The device 1 according to the invention, and schematically represented in FIG. 1, is intended for monitoring a standard anemometric unit 2 of an airplane, in particular a civil transport aircraft, of which only a part of the fuselage 3 with a longitudinal axis 3A has been represented in this FIG. 1 for the sake of simplifying the drawing. It is known that such an anemometric unit 2 is intended to calculate parameters for determining the values of information such as the altitude, velocity, etc. of the airplane. To do this, as is known, said anemometric unit 2 includes: probes 4 which are fitted passing through the fuselage 3 of the airplane, and which access the outside; pressure sensors 5, which are each connected by means of a tube 6 to a probe 4. Such a tube 6, which forms a pneumatic link, is generally connected to the associated pressure sensor 5 by means of a pneumatic connector 7, which allows it to be disconnected and reconnected easily and quickly. An analog/digital converter is furthermore associated with each pressure sensor 5; and a central processing unit 11 which is connected to the pressure sensors 5 by electrical links 12, for example in the form of a communication bus complying with the “ARINC 429” standard. It is, however, also conceivable to integrate the pressure sensors 5 in the central processing unit 11. A civil transport aircraft generally includes two or three anemometeric units 2 of the type described above. The purpose of the device 1 according to the invention, which forms part of a monitoring system 10 specified below (as does said anemometeric unit 2), is to monitor the validity of at least one customary parameter, such as the static pressure Ps, the total pressure Pt or the total temperature TAT, which is calculated by the central processing unit 11 of said anemometeric unit 2. To that end, said device 1 includes, as represented in FIG. 2: means 13 which are connected by a link 14 to the anemometeric unit 2 and which are intended to form at least a number n of first data, each dependent on said monitored parameter Ps, Pt, TAT and received from said anemometeric unit 2, n being an integer greater than or equal to 1. Some of said first data may be calculated from the monitored parameter by the means 13 (which are then data acquisition and calculation means). Others of said first data may correspond to the actual parameter received by said means 13 (which are then simply data acquisition means); means 15 for forming a plurality of p second data, p being an integer greater than or equal to 2. Each of said p second data is of the same type as one of said n first data and depends on at least one value obtained from at least one data source Si which is external to said anemometeric unit 2. Said data sources Si, which are separate from one another, are combined as a set 16 of data sources which is connected by a link 17 to said means 15. Said second data may be calculated from the value obtained from an external data source Si, or may quite simply correspond to this value; means 18 which are respectively connected by links 19 and 20 to said means 13 and 15 in order to calculate, for each of said p second data, a difference between this second datum and a first datum of the same type. In the scope of the present invention, two data are considered to be of the same type when their values relate to the same quantity (velocity, altitude, etc.) and are expressed in the same units, for example two velocities expressed in knots or in km/h, or two altitudes expressed in feet; means 21 which are connected by a link 22 to said means 18, in order to compare the absolute value of each of the differences calculated by said means 18 with a predetermined threshold value, dependent on the type of said difference; and means 23 which are connected by a link 24 to said means 21, in order to deduce from said comparisons: that said monitored parameter Ps, Pt, TAT is invalid if the absolute values of at least two of said various differences are greater than the corresponding predetermined threshold values (that is to say if at least two differences are abnormal); and that said parameter is valid otherwise (that is to say if no difference is abnormal, or if only one is). The monitoring system 10 according to the invention includes: said monitoring device 1; said anemometeric unit 2; and said set 16 of data sources Si. Said monitoring system 10 furthermore includes a display means 25, which is connected by a link 26 to the means 23 and which can display a datum indicating an anomaly (or an invalidity) of a parameter (Ps, Pt, TAT) calculated by the anemometeric unit 2, as appropriate, on at least one visualization device, in particular a customary visualization screen 27, fitted for example in the cockpit of the airplane. The device 1 (or the system 10) according to the invention is therefore capable of rapidly and reliably detecting any anomaly of a parameter calculated by the anemometeric unit 2. It therefore makes it possible to monitor at least one parameter Pt, Ps and/or TAT of the anemometeric unit 2 of the airplane, which requires a high level of reliability, from values which are obtained from said data sources Si external to said anemometeric unit 2, and whose level of reliability may be lower than that of the parameter which is being monitored owing to the use of at least two separate external data sources Si. In a particular embodiment, said first data taken into account by the means 13 are, further to the actual (monitored) parameters Ps, Pt and TAT, the following data: a barometric altitude, calculated in the known way from the value of the static pressure Ps being monitored, this barometric altitude being correctable with the aid of the value of the total temperature TAT being monitored; a velocity of the aircraft with respect to the air, calculated in the known way with the aid of the values of the pressures Ps and Pt being monitored. In a particular embodiment, the said means 15 furthermore take into account the following second data, which are obtained from said set 16 of customary data sources Si: an altitude value provided by a satellite positioning system, in particular the GPS (“Global Positioning System”) system; a total pressure value Pt measured by a probe associated with at least one engine of the aircraft; a static pressure value Ps measured by a probe associated with at least one engine of the aircraft; a total temperature value TAT measured by a probe associated with at least one engine of the aircraft; a velocity value provided by a velocity estimation means; a static pressure value Ps measured by a multifunctional probe; a static pressure value Ps measured by a standby instrument; and a total pressure value Pt measured by a standby instrument. The aforementioned data sources (satellite positioning system, probes associated with the engines, velocity estimation means, multifunctional probe, standby instruments, etc.) are customary sources and form part of said set 16. A standby instrument may, for example, be such as the one described in Application Patent FR-2 784 457. In a preferred embodiment, said means 18 calculate the following differences in order to monitor the static pressure Ps calculated by the anemometeric unit 2: the difference between a barometric altitude, calculated from said static pressure Ps, and an altitude value provided by a satellite positioning system; the difference between a barometric altitude, calculated from said static pressure Ps, and an altitude calculated from a static pressure value measured by a standby instrument; the difference between said static pressure Ps and a static pressure value measured by a probe associated with an engine of the aircraft; the difference between said static pressure Ps and a static pressure value measured by a multifunctional probe; and the difference between a velocity of the aircraft with respect to the air, calculated from said static pressure Ps, and a velocity value provided by a velocity estimation means. Furthermore, said means 18 calculate the following differences in order to monitor the total pressure Pt calculated by the anemometeric unit 2: the difference between said total pressure Pt and a total pressure value measured by a probe associated with an engine of the aircraft; the difference between a velocity of the aircraft with respect to the air, calculated from said total pressure Pt, and a velocity value provided by a velocity estimation means; and the difference between a velocity of the aircraft with respect to the air, calculated from said total pressure Pt, and a velocity calculated from a total pressure value measured by a standby instrument. Also, said means 18 calculate the following differences in order to monitor the total temperature TAT calculated by the anemometeric unit 2: the difference between a barometric altitude, corrected with the aid of said total temperature TAT, and an altitude value provided by a satellite positioning system; the difference between said total temperature TAT and a total temperature value measured by a probe associated with an engine of the aircraft; and the difference between a velocity of the aircraft with respect to the air, calculated from said total temperature TAT, and a velocity value provided by a velocity estimation means. If one or more of the above differences cannot be calculated because at least one of said second data (for example the GPS altitude) is unavailable or is not considered to be valid, the monitoring of said parameters according to the invention may still be carried out for a monitored parameter Ps, Pt, TAT, so long as the differences which are taken into account for monitoring this parameter Ps, Pt, TAT, and which can still be calculated, are calculated from second data obtained from at least two separate external sources Si. In a particular embodiment applied to an aircraft provided with q engines, q being an integer greater than or equal to 3, the values measured by probes associated with said q engines are taken into account and the corresponding differences are calculated. A difference is then considered to be abnormal only if it is abnormal with respect to the measured values relating to at least three of said q engines. This makes it possible to avoid prematurely considering a monitored parameter to be invalid (abnormal difference) in the event that a malfunction of one of the engines of the airplane leads to a malfunction of the probe or probes associated with this engine. In another embodiment applied to an aircraft provided with two engines, the values measured by probes associated with said two engines are taken into account and the corresponding differences are calculated. The differences with respect to the measured values relating to said two engines are considered, and said differences are no longer taken into account in the event of a malfunction by one of said two engines, because there is no longer redundancy of the measurements is no longer available owing to said malfunction. In a particular embodiment, which is represented in FIG. 2, said a system 10 furthermore includes a manual or automatic disabling means 28, which is connected by a link 29 to the device 1 and which is intended to disable the monitoring of the validity of the monitored parajmeter or parameters when the aircraft is in at least one particular flight phase such as take-off or landing, and when it is passing through turbulence zones. This allows this monitoring to be made more robust by preventing a monitored parameter from prematurely being considered to be invalid.
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20040706
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20080819
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20050113
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62525.0
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FREJD, RUSSELL WARREN
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METHOD AND DEVICE FOR MONITORING THE VALIDITY OF AT LEAST ONE PARAMETER WHICH IS CALCULATED BY AN ANEMOMETERIC UNIT OF AN AIRCRAFT
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UNDISCOUNTED
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ACCEPTED
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10,883,860
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ACCEPTED
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Cache memory system and method capable of adaptively accommodating various memory line sizes
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A cache memory system capable of adaptively accommodating various memory line sizes comprises cache memory and cache logic. The cache memory has sets of ways. The cache logic is configured to request a memory line in response to a cache miss, and the memory line represents a portion of a way line. The cache logic is configured to select one of the ways based on which portion of the way line is represented by the memory line. The cache logic is further configured to store the memory line in the selected way.
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1. A cache memory system capable of adaptively accommodating various memory line sizes, comprising: cache memory having sets of ways; and cache logic configured to request a memory line in response to a cache miss, the memory line representing a portion of a way line, the cache logic configured to select one of the ways based on which portion of the way line is represented by the memory line, the cache logic further configured to store the memory line in the selected way. 2. The system of claim 1, wherein the cache logic is further configured to ensure that a remaining portion of the way line is not written to the selected way. 3. The system of claim 1, wherein the cache logic is configured to select the selected way from a first plurality of ways if the memory line represents an upper portion of the way line, and wherein the cache logic is configured to select the selected way from a second plurality of ways if the memory line represents a lower portion of the way line. 4. The system of claim 1, wherein the cache logic is configured to allocate a first plurality of ways to upper way line portions and to allocate a second plurality of ways to lower way line portions, the cache logic further configured to ensure that the selected way is allocated to the way line portion represented by the memory line. 5. The system of claim 1, wherein the retrieved memory line is associated with an address having a tag and an index, and wherein the cache logic comprises tag compare logic configured to transmit a hit signal having a value based on whether the cache memory is storing data from a memory block identified by the tag and index, and wherein the cache logic further comprises hit logic configured manipulate the hit signal based on whether data from the memory block and stored in the cache memory corresponds to the memory line. 6. The system of claim 1, wherein the cache logic is capable of operating in at least a first mode of operation and a second mode of operation, the cache logic configured to receive a first plurality of memory lines when operating in the first mode of operation and to receive a second plurality of memory lines when operating in the second mode of operation, each of the first plurality of memory lines having a first size and each of the second plurality of memory lines having a second size, wherein the cache logic is configured such that each of the first plurality of memory lines is assigned to and fully associative within a respective one of the sets, and wherein the cache logic is configured such that each of the second plurality of memory lines is assigned to and partially associative within a respective one of the sets. 7. A cache memory system, comprising: cache memory having a tag array and a data array; tag compare logic configured to receive a tag of an address associated with a read request and a tag retrieved from the tag array based on an index of the address, the tag compare logic further configured to compare the received tags and to transmit a hit signal based on a comparison of the received tags, the hit signal indicating whether an entry of the data array is storing data from a memory block identified by the tag and index of the address; and hit logic configured to manipulate the transmitted hit signal based on whether the data from the memory block includes data requested by the read request, wherein the cache memory system is capable of accommodating various memory line sizes. 8. The system of claim 7, further comprising a multiplexor configured to select the data stored in the entry of the data array based on the hit signal. 9. The system of claim 7, wherein the hit logic is configured to manipulate the hit signal based on at least one bit of the address. 10. The system of claim 7, wherein the data array is allocated to upper way line portions, and wherein the hit logic is configured to change the hit logic signal if the data requested by the read request corresponds to a lower portion of a way line. 11. A cache memory system capable of adaptively accommodating various memory line sizes, comprising: cache memory having sets of ways; and cache logic capable of operating in at least a first mode of operation and a second mode of operation, the cache logic configured to receive a first plurality of memory lines when operating in the first mode of operation and to receive a second plurality of memory lines when operating in the second mode of operation, each of the first plurality of memory lines having a first size and each of the second plurality of memory lines having a second size, wherein the cache logic is configured such that each of the first plurality of memory lines is assigned to and fully associative within a respective one of the sets, and wherein the cache logic is configured such that each of the second plurality of memory lines is assigned to and partially associative within a respective one of the sets. 12. The system of claim 11, wherein the cache logic is configured to receive a mode signal and to operate in one of the modes of operation based on the mode signal. 13. The system of claim 11, wherein the cache logic is configured to ensure that memory lines from a single block of memory are respectively stored to different ways of the same set when operating in the second mode of operation. 14. The system of claim 13, wherein each of the memory lines from the single block of memory is associated with an address having a tag and an index identifying the single block of memory. 15. A cache memory system capable of adaptively accommodating various memory line sizes, comprising: cache memory having sets of ways; means for requesting a memory line in response to a cache miss, the memory line representing a portion of a cache line; means for selecting one of the ways based on which portion of the way line is represented by the memory line; and means for storing the memory line in the selected way. 16. A method for adaptively accommodating various memory line sizes within cache memory systems, comprising the steps of: receiving a memory line in a cache memory system, the cache memory system having sets of ways and capable of operating in at least a first mode of operation and a second mode of operation; storing the memory line in one of the ways of one of the sets based on an address associated with the memory line; determining whether the cache memory system is operating in the first or the second mode of operation; controlling, if the cache memory system is operating in a first mode of operation, the cache memory system such that the memory line is fully associative within the one set based on the determining step; and controlling, if the cache memory system is operating in a second mode of operation, the cache memory system such that the memory line is partially associative within the one set based on the determining step. 17. The method of claim 16, further comprising the step of receiving a mode signal indicating a mode of operation of the cache memory system, wherein the determining step is based on the mode signal. 18. The method of claim 16, further comprising the step of ensuring that memory lines from a single block of memory are respectively stored to different ways of the same set when the cache memory system is operating in the second mode of operation. 19. The method of claim 16, further comprising the steps of: requesting the memory line in response to a cache miss, the memory line representing a portion of a way line; and selecting the one way based on which portion of the way line is represented by the memory line, wherein the storing step is based on the selecting step. 20. The method of claim 19, wherein the address has a tag and an index, the method further comprising the steps of: transmitting a hit signal having a value based on whether the cache memory is storing data from a memory block identified by the tag and index; and manipulating the hit signal based on the determining step. 21. The method of claim 20, wherein the manipulating step is further based on whether data from the memory block and stored in the cache memory corresponds to the memory line. 22. A method for adaptively accommodating various memory line sizes within cache memory systems, comprising the steps of: receiving a memory line in a cache memory system, the cache memory system having sets of ways and the memory line representing a portion of a way line; selecting one of the sets based on an address associated with the memory line; selecting one of the ways of the selected set based on which portion of the way line is represented by the memory line; and storing the memory line in the selected way. 23. The method of claim 22, further comprising the step of ensuring that a remaining portion of the way line is not written to the selected way. 24. The method of claim 22, wherein the selecting one of the ways step comprises the steps of: selecting the one way from a first plurality of ways of the selected set if the memory line represents an upper portion of the way line; and selecting the one way from a second plurality of ways of the selected set if the memory line represents a lower portion of the way line. 25. The method of claim 22, further comprising the steps of: allocating a first plurality of ways to upper way line portions; allocating a second plurality of way to lower way line portions; and ensuring that the selected way is allocated to the way line portion represented by the memory line. 26. A method for adaptively accommodating various memory line sizes within cache memory systems, comprising the steps of: receiving a memory line in a cache memory system, the cache memory system having a tag array and a data array; receiving an address associated with the memory line in the cache memory system, the address having a tag and an index identifying a block of memory storing the memory line; retrieving a tag from the tag array based on the index; comparing the received tag and the retrieved tag; transmitting a hit signal based on the comparing, the hit signal indicating that the data array is storing data from the memory block; and manipulating the transmitted hit signal based on whether the data from the memory block corresponds to the memory line. 27. The method of claim 26, wherein the manipulating step is based on at least one bit of the address. 28. The method of claim 26, further comprising the step of allocating the data array to upper way line portions, wherein the manipulating step comprises the step of changing the hit signal if the memory line corresponds to a lower portion of a way line. 29. The method of claim 26, wherein cache memory within the cache memory system has sets of ways and wherein the memory line represents a portion of a way line, the method further comprising the steps of: selecting one of the sets based on the address; selecting one of the ways of the selected set based on which portion of the way line is represented by the memory line; and storing the memory line in the selected way.
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RELATED ART In processing instructions of a computer program, it is often necessary for a processor to retrieve data from memory. The retrieval of such data takes a finite amount of time, and delays in processing instructions can be caused by the processor waiting on data to be retrieved from memory. In an effort to minimize such delays, most processors utilize a local memory structure, referred to as a “cache.” The cache provides a local storage area for the processor such that data can be loaded into the cache and reused by the processor without having to repeatedly retrieve the data from other memory areas. The amount of time required to access data stored in the cache is generally much less than the time required to access data from other memory within a computer system. Thus, if data requested by a processor is available in the cache, then the amount of time required to provide the data to the processor can be significantly decreased by retrieving the data from the cache rather than searching for and retrieving the data from other memory. Therefore, when a processor submits a data request, the cache is usually searched to determine whether the most recent version of the requested data is stored in the cache. If so, the data is retrieved from cache and provided to the processor. However, if the most recent version of the requested data is not available in the cache, then other areas of the computer system's memory are searched for the requested data. Once the requested data is located, this data is retrieved and provided to the processor. The data is also stored in the cache so that, if the data is later requested, it can be retrieved from the cache until such data in the cache is overwritten or invalidated. Most caches have a limited number of entries, referred to as “ways,” where data can be stored. Further, the ways are normally grouped into sets. Each set typically has the same number of ways, and each way typically has the same bit length. For example, a cache that has 8 ways per set and n number of sets has 8n possible entries or ways where data can be stored. Thus, if each way is able to store 128 bytes, then the cache is able to store up to 1024n bytes of information. Note the term “way line” generally refers to a separately addressable block of data of sufficient size for filling a single way in the cache. Access to the way lines is provided by the use of addresses, each of which normally comprises a tag, an index, and an offset. The tag and index uniquely identify a particular way line, and the offset uniquely identifies a particular byte within the way line. In many computer systems, the cache is designed such that the byte lengths of the ways match the byte length of memory lines. A “memory line” refers to a separately addressable block of data capable of being retrieved from memory and transmitted over the system interface in a single transmit operation (e.g., as a single data word). The byte lengths of the memory lines in a computer system are usually limited by the system's hardware resources. For example, the size of the system interface limits the computer system's memory line size. Further, memory controllers that control the storage and retrieval of data to and from memory are usually hardwired to handle one memory line for each read and write operation performed by the memory controllers. Since data is normally stored to and retrieved from memory on a memory line basis, each way in a cache is normally selected such that the size of a way line equals the size of a memory line. Thus, a retrieved memory line may be stored as a way line in and completely fill a single way. However, all computer systems do not use the same memory line size. Thus, the number of computer systems compatible with a given processor and cache configuration is limited. As an example, a cache designed for a computer system that employs 64 byte memory lines and, therefore, a 64 byte system interface may be incompatible with a computer system that employs 128 byte memory lines and vice versa. In general, it is desirable for a cache to be adaptable to accommodate different memory line sizes so that the range of computer systems in which the cache may be used is increased. Some caches have been designed to accommodate memory line sizes that differ by a factor of two. For example, a cache having ways that are 128 bytes in length is able to receive and store 128 byte memory lines. In this regard, when the cache receives a read request that requests a particular byte of data, cache logic within the cache determines whether the requested data is available in the cache. A cache hit occurs when the requested data is in the cache and can be provided to the processor without searching other memory for the requested data. A cache miss occurs when the requested data is not available in the cache and other memory areas must be searched to locate the requested data. In response to a cache miss, the cache logic transmits a read request to a memory controller. Based on the read request, the memory controller retrieves the 128 byte memory line that contains the requested data and transmits this memory line to the cache, which stores the 128 byte memory line in a single way. In other embodiments, the aforedescribed cache can be implemented in a computer system that employs 64 byte memory lines. In such an embodiment, cache logic within the cache sends two read requests for each cache miss. In this regard, a first one of the memory requests causes retrieval of a 64 byte memory line that includes the data requested by the processor. This 64 byte memory line represents half of a way line and is stored in half of a particular cache way of the cache. To fill the particular cache way with the other half of the way line, the second read request causes retrieval of a 64 byte memory line that is contiguous with the other 64 byte memory line retrieved by the first read request. The 64 byte memory line retrieved by the second read request is stored in the same way as the 64 byte memory line retrieved by the first read request such that the entire way is filled with valid data. Filling the entire way with valid data, as described above, helps to ensure that valid data is retrieved from the cache in response to a cache hit regardless of which portion of a way contains the requested data. However, generating multiple read requests to ensure that each way is completely filled with valid data, as described above, undesirably introduces system interface delays that can adversely impact the performance of the computer system. Techniques for reducing or eliminating such delays are generally desirable. SUMMARY OF THE DISCLOSURE Generally, embodiments of the present disclosure provide systems and methods capable of adaptively accommodating various memory line sizes. A cache memory system in accordance with an exemplary embodiment of the present disclosure comprises cache memory and cache logic. The cache memory has sets of ways. The cache logic is configured to request a memory line in response to a cache miss, and the memory line represents a portion of a way line. The cache logic is configured to select one of the ways based on which portion of the way line is represented by the memory line. The cache logic is further configured to store the memory line in the selected way. A cache memory system in accordance with another embodiment of the present disclosure comprises cache memory, compare logic, and hit logic. The cache memory has a tag array and a data array, and the tag compare logic is configured to receive a tag of an address associated with a read request and a tag retrieved from the tag array based on an index of the address. The tag compare logic is further configured to compare the received tags and to transmit a hit signal based on a comparison of the received tags. The hit signal indicates whether an entry of the data array is storing data from a memory block identified by the tag and index of the address. The hit logic is configured to manipulate the transmitted hit signal based on whether the data from the memory block includes data requested by the read request. A cache memory system in accordance with yet another embodiment of the present disclosure comprises cache memory and cache logic. The cache memory has sets of ways, and the cache logic is capable of operating in at least a first mode of operation and a second mode of operation. The cache logic is configured to receive a first plurality of memory lines when operating in the first mode of operation and to receive a second plurality of memory lines when operating in the second mode of operation. Each of the first plurality of memory lines has a first size, and each of the second plurality of memory lines has a second size. The cache logic is further configured such that each of the first plurality of memory lines is assigned to and fully associative within a respective one of the sets and such that each of the second plurality of memory lines is assigned to and partially associative within a respective one of the sets. BRIEF DESCRIPTION OF THE DRAWINGS The disclosure can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Furthermore, like reference numerals designate corresponding parts throughout the several views. FIG. 1 is a block diagram illustrating a computer system that employs a cache memory system in accordance with an exemplary embodiment of the present disclosure. FIG. 2 is a block diagram illustrating an exemplary address that may be used to access data in the computer system depicted by FIG. 1. FIG. 3 is a block diagram illustrating cache memory within the system depicted by FIG. 1. FIG. 4 is a block diagram illustrating an exemplary embodiment of the cache memory system depicted in FIG. 1. FIG. 5 is a circuit diagram illustrating an exemplary embodiment of hit logic depicted in FIG. 4. FIG. 6 is a flow chart illustrating an exemplary methodology implemented by the cache memory system depicted by FIG. 1 in responding to a read request. FIG. 7 is a flow chart illustrating an exemplary methodology implemented by the cache memory system depicted by FIG. 1 in determining whether or not to provide a cache hit determination in response to a read request. DETAILED DESCRIPTION Embodiments of the present disclosure generally relate to caches capable of adaptively accommodating various memory line sizes. A cache in accordance with an exemplary embodiment of the present disclosure is capable of operating in at least two modes of operation depending on the size of the memory lines to be interfaced with the cache. The cache comprises memory having entries or ways of n bytes. In a first mode of operation, the cache is implemented in a computer system that provides n-byte memory lines. In this mode of operation, the cache submits, for each cache miss, a read request to a memory system. In response to the read request, a memory line of n-bytes representing a full way line is retrieved from memory and transmitted to the cache via a system interface. The cache stores the n-byte memory line received from the system interface into a single way of a set identified by the address. In a second mode of operation, the cache is implemented in a computer system that provides memory lines of a smaller size (e.g., (n/2)-byte memory lines). In the second mode of operation, the cache submits, for each cache miss, a read request having an address to a memory system. In response to the read request and based on the address, a memory line of x bytes, where x is less than n, representing only a portion of a way line is retrieved from memory and transmitted to cache via a system interface. Depending on which portion of the way line is retrieved, the cache selects one of the ways of the set identified by the address and stores the x bytes into the selected way. The cache ensures that, if another portion of the same way line is requested, such other portion will be stored in a different way of the same set. Moreover, any of the x bytes stored in the selected way may later be used to satisfy a read request from a processor regardless of whether the entire way line is stored in the cache. Accordingly, multiple memory reads for a single read request are unnecessary. FIG. 1 depicts a computer system 20 in accordance with an exemplary embodiment of the present disclosure. The system 20 comprises a processor 22 configured to execute instructions in accordance with well-known instruction processing techniques. The processor 22 is coupled to and in communication with a cache memory system, also referred to as “cache 25.” The cache 25 comprises cache memory 31 for temporarily storing data used by the processor 22 and cache logic 33 for controlling the operation and functionality of the cache 25. The cache logic 33 is preferably implemented in hardware, although it is possible to implement portions of the functionality of the cache logic 33 in software, if desired. To reduce the amount of time necessary for the processor 22 to access data in the cache 25, the processor 22 and cache 25 preferably reside in a single integrated circuit 34. The cache 25 is coupled to a system interface 36, which allows the cache to communicate with other system components, such as one or more memory systems 42. The system interface 36 comprises a number of connections to allow a memory line of n bytes to be communicated in a single transmit operation (e.g., as a single data word) to the cache 25 from memory system 42 or from other resources of the computer system 20. The memory system 42 comprises memory 43 and one or more memory controllers 48 for controlling the storage and the retrieval of data to and from the memory 43. The memory controller 48 may be implemented in hardware, software, or a combination thereof. In operation, the processor 22 generates read and write requests while executing instructions of one or more computer programs. A read request refers to an operation that requests data to be retrieved and returned to the processor 22. A write request refers to an operation that requests data to be written to a particular memory location. Each read request comprises an address identifying a location within memory 43 from where the requested data is to be retrieved, and each write request comprises an address identifying a location within memory 43 where data is to be written. Note that the system 20 may include additional processors and caches (not specifically shown in FIG. 1). Either a memory controller 48 or one of the additional processors may respond to a read request. In this regard, if the data being requested is located in a cache of an additional processor, then the additional processor may respond with the requested data. Otherwise, the requested data is retrieved by a memory controller 48. As shown by FIG. 2, each address 52 is composed of at least three parts, a tag 55, an index 56, and an offset 57. The tag 55 and index 56 identify a block 49 of memory 43 in which the requested data byte or bytes reside. The size of the memory blocks 49 matches the size of the cache memory 31 such that each memory block 49 defines a different way line. For example, in one embodiment, the length of each way in the cache 25 and each memory block 49 is 128 bytes, although other byte lengths are possible in other embodiments. The offset 57 uniquely identifies, within the memory block 49 identified by the tag 55 and index 56, the particular byte or bytes that are to be retrieved (in the case of a read request) or overwritten (in case of a write request). Thus, using the tag 55 and index 56 of the address 52 within a read request, it possible to find the memory block 49 storing the requested data byte or bytes, and using the offset 57, it is possible to find the requested data byte or bytes within the foregoing memory block 49. In some embodiments, the address 52 may also include a size request that identifies the number of bytes being requested, and the size request in conjunction with the offset may be used to identify the requested data byte or bytes. As shown by FIG. 3, the cache memory 31 is segmented into an x number of sets, where x is any positive integer. Each set is composed of a plurality of ways, and each way is a cache memory location where a full way line may be stored. In a preferred embodiment, each set has the same number of ways. In FIG. 3, each set is shown as having four ways for simplicity. However, in other embodiments, other numbers of ways within each set are possible. The index 56 of address 52 uniquely identifies one of the sets of the cache 25, and multiple addresses may have the same index 56. Thus, way lines from different memory blocks 49 may be stored in the same set. In one embodiment, the cache 25 is implemented within a system 20 having an interface 36 of sufficient size such that the memory system 42 can transmit n-byte memory lines over the interface 36. Further, each way of the cache 25 preferably has a length of n bytes such that a single memory line fills a single way. Thus, a single memory line representing a full way line can be retrieved from memory 43 and transmitted in a single transmit operation over system interface 36 to cache 25. In such an embodiment, the operation of the cache 25 is similar to that of conventional caches. In this regard, when the cache 25 receives a read request from the processor 22, the cache logic 33 determines whether the requested data is stored in the cache 25. Note that a cache hit refers to the condition that the requested data is stored in the cache 25 and can be retrieved directly from the cache 25. Further, a cache miss refers to the condition that the requested data is not presently available in the cache 25. In the event of a cache hit, the cache logic 33 retrieves the requested data from the cache memory 31 and transmits this data to the processor 22. However, in the event of a cache miss, the cache logic 33 transmits a read request over the system interface 36 to the memory system 42. Based on the address 52 in the read request, the memory controller 48 retrieves a memory line representing a full way line that contains the requested data. In this regard, the memory controller 48 retrieves the memory block 49 identified by the tag 55 and index 56 of the received memory address 52. The memory controller 48 then transmits the retrieved way line, along with the address 52 of the read request, over the system interface 36 to the cache 25. Upon receiving the way line, the cache logic 25 stores the way line in one of the ways of a set identified by the index 56 of the aforementioned address 52. Note that the cache logic 25 also transmits the requested data to the processor 22 in order to satisfy the aforementioned read request previously issued by the processor 22. The requested data may be transmitted before or after the way line is written in the cache memory 31. Once the way line is written in the cache 25, then future read requests requesting data within the way line may be retrieved directly from the cache 25 without submitting a read request to memory system 42 until the way line is invalidated or overwritten. In this regard, a way line is overwritten when a new way line is stored in the same way. Further, a way line is invalidated when the data defining the way line is no longer the most recent version of such data. For example, a memory block 49 may be updated once the way line from this memory block 49 has been written to the cache 25. If such an update occurs, then the way line is preferably invalidated such that a read request requesting one or more bytes within the way line is retrieved from memory system 42 rather than the previously written way line residing in the cache 25. To invalidate a way line stored in the cache, control data within the cache 25 is manipulated such that a cache miss occurs in response to a read request having an address identifying the memory block 49 from which the way line was previously retrieved. In another embodiment, the cache 25 is implemented within a system 20 having an interface 36 capable of transmitting memory lines of only (n/2) bytes. For example, if each way in the cache 25 is capable of storing 128 bytes, then the system interface 36 is capable of transmitting 64 byte memory lines. In such an embodiment, the cache logic 33 is configured to allocate half of the ways of each set to an upper half of each way line that may be stored in the set, and the cache logic 33 is configured to allocate the remaining half of the ways in each set to a lower half of each way line that may be stored in the set. Thus, for each way line, the upper half of the way line may be stored in half of the ways of a particular set, and the lower half of the way line may be stored in the other half of the ways of the particular set. To illustrate the foregoing, assume that the odd ways (i.e., ways 1 and 3) are allocated to the upper halves of the way lines and that the even ways (i.e., ways 0 and 2) are allocated to the lower halves of the way lines, although other allocation schemes are possible in other embodiments. When a read request from processor 22 results in a cache miss, the cache logic 33 transmits the read request over system interface 36 to memory system 42. In response, the memory controller 48 retrieves a memory line representing half of a way line from the memory block 49 identified by the tag 55 and index 56 of the address 52 included in the read request. In this regard, if the offset 57 indicates that the requested data is in the upper half (i.e., the half having the most significant bits) of the identified memory block 49, then the memory controller 48 retrieves the upper half of the way line and transmits the upper half of the way line, along with the address 52 of the read request, over system interface 36 to cache 25. If the offset 57 indicates that the requested data is in the lower half (i.e., the half having the least significant bits) of the identified memory block 49, then the memory controller 48 retrieves the lower half of the way line and transmits the lower half of the way line, along with the address 52 of the read request, over system interface 36 to cache 25. Upon receipt of the retrieved way line half, the cache logic 33 stores the way line half in one of the ways of the set identified by the index 56 of the address 52 depending on whether the retrieved way line half is the upper or lower half of the way line. In particular, if the way line half is the upper half of the way line, then the cache logic 33 stores the way line half in one of the ways allocated to the upper way line halves (i.e., either way 1 or 3 in the instant example). However, if the way line half is the lower half of the way line, then the cache logic 33 stores the way line half in one of the ways allocated to the lower way line halves (i.e., either way 2 or 4 in the instant example). Note that the most significant bit of the offset 57 indicates whether the received way line half is an upper way line half or a lower way line half. In this regard, if this bit is asserted, then the received way line half is an upper way line half, and if this bit is deasserted, then the received way line half is a lower way line half. Thus, the cache logic 33 may be configured to select the way that is to store the received way line half based on the offset 57 and, in particular, the most significant bit of the offset 57 in the instant example. In other examples, other portions of the address may be used to select the way that is to store the received way line portion. Note that if data in the other half of the aforementioned way line (i.e., the non-retrieved half) is requested, then the other half will not be stored in the same way as the retrieved half. It is unnecessary for this other half to be retrieved until a read request identifying data in this other half is issued by the processor 22. To determine whether there is a cache hit in response to a read request from processor 22, the cache logic 33 determines whether the read request is requesting data in an upper or lower half of a way line. Note that this determination can be made by analyzing the offset 57 and, in particular, the most significant bit of the offset. If the read request is requesting data in an upper half of a way line, then the cache logic 33 determines whether any of the ways allocated to the upper way line halves is storing data associated with the address 52 in the read request. In the instant example, the cache logic 33 determines whether way 1 or 3 in the set identified by the index 56 is storing data identified by the address 52. If so, then the cache logic 33 retrieves the requested data from the appropriate way 1 or 3 and transmits the requested data to the processor 22. Otherwise, the cache logic 33 indicates a cache miss and transmits the read request to memory system 42. If the read request is requesting data in a lower half of a way line, then the cache logic 33 determines whether any of the ways allocated to the lower way line halves is storing data associated with the address 52 in the read request. In the instant example, the cache logic 33 determines whether way 2 or 4 in the set identified by the index 56 is storing data identified by the address 52. If so, then the cache logic 33 retrieves the requested data from the appropriate way 2 or 4 and transmits the requested data to the processor 22. Otherwise, the cache logic 33 indicates a cache miss and transmits the read request to memory system 42. There are various configurations of the cache logic 33 that may be used to implement the aforedescribed functionality. FIG. 4 depicts an exemplary embodiment of the cache 25. For simplicity, the cache 25 of FIG. 4 is described hereafter as having only two ways per set. Thus, each set has only two ways, referred to hereafter as “way 0” and “way 1,” respectively. It will be assumed hereafter that, in at least one mode of operation, way 1 is allocated to upper way line halves and way 0 is allocated to lower way line halves. In other embodiments, similar circuitry may be used to implement a cache having a greater number of ways per set. The cache 25 shown by FIG. 4 has two tag arrays 114 and 115 and two data arrays 116 and 117. Each of the arrays 114-117 is an area of cache memory 31 (FIG. 1) where data can be stored in the cache 25. For example, each array 114-117 may be a separate register, although other configurations of the arrays 114-117 are possible in other embodiments. The data array 116 is used to implement all ways allocated to the lower way line halves. In the instant example, each entry of the array 116 represents way 0 of a different set. Further, data array 117 is used to implement all ways allocated to the upper way line halves. In the instant example, each entry of the array 117 represents way 1 of a different set. Each entry of the data array 116 corresponds to an entry of the tag array 114, and each entry of the data array 117 corresponds to an entry of the tag array 115. When at least a portion of a way line is stored in an entry of the data array 116, the tag 55 identifying the memory block 49 (FIG. 1) from where the way line portion was retrieved is stored in the corresponding entry of the tag array 114. Note that the corresponding entries in the data array 116 and tag array 114 are referenced by or, in other words, uniquely identified by the same index 56. Further, when at least a portion of a way line is stored in an entry of the data array 117, the tag 55 identifying the memory block 49 (FIG. 1) from where the way line portion was retrieved is stored in the corresponding entry of the tag array 115. Note that the corresponding entries in the data array 117 and tag array 117 are referenced by or, in other words, uniquely identified by the same index 56. The cache 25 depicted by FIG. 4 also comprises fill logic 122, hit logic 125, and tag compare logic 131 and 133. The aforementioned logic 122, 125, 131, and 133 implements a portion of the cache logic 33 depicted in FIG. 1. The fill logic 122 indicates when data from a way line is to be stored in the cache 25. Further, the hit logic 125 and the tag compare logic 131 and 133 operate in conjunction to indicate whether a read request received from the processor 22 results in a cache hit or a cache miss. The operation and functionality of the aforementioned logic 122, 125, 131, and 133 will be described in greater detail below. A one-bit signal 137, referred to hereafter as “mode signal,” is provided to indicate the mode of operation for the cache 25. In this regard, the mode signal is asserted when the cache 25 is implemented in a computer system 20 that is configured to provide the cache 25 n-byte memory lines for storage in the data arrays 116 and 117, where n is the byte length of the ways within the arrays 116 and 117. Such a mode of operation will be referred to hereafter as the “full way line mode of operation.” If the cache 25 is implemented in a computer system 20 that is configured to provide the cache 25 with (n/2)-byte memory lines, then the mode signal is deasserted. Such a mode of operation will be referred to hereafter as the “half way line mode of operation.” Note that the mode signal 137 may comprise a plurality of bits (e.g., when system 20 is capable of accommodating more than two memory line sizes). In the embodiments described hereafter, each memory line received by the cache 25 during the full way line mode of operation is fully associative within the set identified by the memory line's address. Further, each memory line received by the cache 25 during another mode of operation in which the memory lines represent portions of way lines (e.g., the half way line mode of operation) is partially associative within the set identified by the memory line's address. As used herein, a memory line is “fully associative” within a set when it can be stored in any way of the set, and a memory line is “partially associative” within a set when it can be stored in only some of the ways of the set. As an example, in the half way line mode of operation, a memory line representing a lower half of a way line can be stored in any way allocated to lower way line halves in the set identified by the memory line's address. However, the cache logic 33 ensures that such a memory line is not stored in a way allocated to upper way line halves. Since the memory line can be stored in at least one but less than all of the ways of the set identified by the index 56 of its address, the memory line is partially associative within the identified set during the half cache line mode operation. As shown by FIG. 4, the cache 25 is provided two other one-bit signals 142 and 144 respectively referred to as a “read signal” and “fill signal.” The read signal 142, when asserted, indicates that the cache 25 is performing a read operation or, in other words, is attempting to service a read request from the processor 22. The fill signal 144, when asserted, indicates that the cache 25 is performing a fill operation or, in other words, is processing and storing at least a portion of a way line received from memory system 42 (FIG. 1). The performance of read and fill operations will now be described in more detail below. When the cache 25 receives from memory system 42 a memory line to be stored in the cache 25 during the full way line mode of operation (i.e., when the cache 25 is to perform a fill operation) during the full way line mode of operation, the cache 25 stores the memory line, representing an entire way line, in one of the data arrays 116 or 117. In this regard, the tag 55 and index 56 of the address 52 associated with the way line are transmitted to the arrays 114-117. Further, the fill signal is asserted to indicate that a fill operation is to be performed, and fill data 141 (i.e., the way line to be stored in the cache 25) is provided to the data arrays 116 and 117. The fill logic 122, based on the mode signal, determines that the fill data may be stored in either way 0 or 1. Thus, the fill logic 122 selects between the two available ways 0 or 1 for the optimal way to which the fill data is to be stored. Note that the fill logic 122 may utilize a replacement algorithm to select the optimal way. In this regard, replacement algorithms strategically select between available ways for performing fill operations in order to reduce the likelihood of cache misses. Such fill algorithms are known in the art and are widely used in conventional caches. The fill logic 122 of FIG. 4 may employ a known or future-developed replacement algorithm to select between available ways when performing fill operations. If the fill logic 122 selects way 0 to complete the fill operation, then the fill logic 122 asserts fill signals 152 and 153 and deasserts fill signals 154 and 155. When fill signal 152 is asserted, the tag array 114 stores the tag 55 being received by the tag array 114 into the entry identified by the index 56 being received by the tag array 114. Further, when the data array 116 receives an asserted fill signal 153, the data array 116 stores the fill data 141 in the entry identified by the index 56 being received by the data array 116. Thus, if the fill logic 122 selects way 0 to complete the fill operation, the entire way line is stored in data array 116. If the fill logic 122 selects way 1 to complete the fill operation, then the fill logic 122 deasserts fill signals 152 and 153 and asserts fill signals 154 and 155. When fill signal 154 is asserted, the tag array 115 stores the tag 55 being received by the tag array 115 into the entry identified by the index 56 being received by the tag array 115. Further, when the data array 117 receives an asserted fill signal 155, the data array 117 stores the fill data 141 in the entry identified by the index 56 being received by the data array 117. Thus, if the fill logic 122 selects way 1 to complete the fill operation, the received memory line, representing an entire way line, is stored in data array 117. When the cache 25 receives from processor 22 a read request (i.e., when the cache 25 is performing a read operation), the cache 25 determines whether the requested data is available in the cache 25 and, if so, retrieves the requested data. In this regard, in responding to a read request, the tag 55 and index 56 of the address 52 included in the read request is transmitted to the tag arrays 114 and 115 and the data arrays 116 and 117. Further, the read signal 142 is asserted. The tag array 114 retrieves the tag stored in the entry identified by the received index 56, and the tag array 114 transmits the retrieved tag to the tag compare logic 131, which also receives the tag 55 from the read request address 52. The tag compare logic 131 compares the tag from tag array 114 and the tag 55 from the read request. If the two tags match, the tag compare logic 131 asserts signal 165. Otherwise, the tag compare logic 131 deasserts signal 165. In the full way line mode of operation, the assertion of signal 165 indicates a cache hit for data array 116 (i.e., indicates that the requested data is available in the data array 116). Further, in the full way line mode of operation, the hit logic 125 allows the signal 165 to pass through the hit logic 125 without change and to be output as signal 169. Thus, the requested data is available in data array 116 when the signals 165 and 169 are asserted. The tag array 115 retrieves the tag stored in the entry identified by the received index 56, and the tag array 115 transmits the retrieved tag to tag compare logic 133, which also receives the tag 55 from the read request address 52. The tag compare logic 133 compares the tag from tag array 115 and the tag 55 from the read request. If the two tags match, the tag compare logic 133 asserts signal 175. Otherwise, the tag compare logic 133 deasserts signal 175. In the full way line mode of operation, the assertion of signal 175 indicates a cache hit for data array 117 (i.e., indicates that the requested data is available in the data array 117). Further, in the full way line mode of operation, the hit logic 125 allows the signal 175 to pass through the hit logic 125 without change and to be output as signal 179. Thus, the requested data is available in data array 117 when the signals 175 and 179 are asserted. If both signals 169 and 179 output from the hit logic 125 are deasserted, then a cache miss has occurred (i.e., the request data is not available in cache 25). Thus, the read request is transmitted to memory system 42 where the requested data is retrieved from memory 43 and then stored in cache 25 as a fill operation. If, however, one of the signals 165 or 179 is asserted, then a cache hit has occurred. In such a situation, the cache 25 retrieves the requested data and transmits this data to processor 22. In this regard, the data array 116 in response to an asserted read signal 142 transmits to multiplexor 181 the way line stored in the entry identified by the index 55 being received by the array 116. Further, the data array 117 in response to an asserted read signal 142 transmits to multiplexor 181 the way line stored in the entry identified by the index 55 being received by the array 117. The multiplexor 181 then selects and transmits the way line from the data array 116 or 117 associated with the cache hit based on the signals 169 and 179 output from the hit logic 125. In particular, if signal 169 is asserted, the multiplexor 181 selects and transmits the way line from the data array 116. If signal 179 is asserted, the multiplexor 181 selects and transmits the way line from the data array 117. Further, a multiplexor 184 receives the way line transmitted from multiplexor 181. Based on the offset 57 of the address 52 included in the read request, the multiplexor 184 selects the requested data from the received way line and transmits this data to the processor 22. Thus, if there is a cache hit, the data requested by the read request is retrieved from cache 25 and transmitted to processor 22. Operation of the cache 25 will now be described for the half way line mode of operation. In the half way line mode, the cache 25 of FIG. 4 operates essentially the same as in the full way line mode except as otherwise described below. Note that the mode signal 137 is deasserted to indicate that the cache 25 is to operate in the half way line mode instead of the full way line mode. In the half way line mode, half of the ways of each set are allocated to the upper way line halves, and the other half of the ways of each set are allocated to the lower way line halves. In the instant embodiment, way 1 is allocated to the upper way line halves, and way 0 is allocated to the lower way line halves. In a fill operation, the cache 25 receives a memory line, representing half of a way line, and an address 52 from system interface 36, and the fill signal 144 is asserted. If the way line half received from system interface 36 is an upper half of a way line, then the fill logic 122 ensures that the way line half is stored in a way allocated to upper way line halves. In the instant embodiment, way 1 is the only way allocated to upper way line halves. Thus, the fill logic 122 ensures that the way line half is stored in way 1 of the set identified by the index 56 in the received address 52. The foregoing is achieved by deasserting fill signals 152 and 153 while asserting signals 154 and 155 when the most significant bit of the offset 57 is asserted. If multiple ways of the identified set are allocated to the upper way line halves in other embodiments, then the fill logic 122 may employ a replacement algorithm to select one of these ways for the storage of the way line half. If the way line half received from system interface 36 is a lower half of a way line, then the fill logic 122 ensures that the way line half is stored in a way allocated to lower way line halves. In the instant embodiment, way 0 is the only way allocated to lower way line halves. Thus, the fill logic 122 ensures that the way line half is stored in way 0 of the set identified by the index 56 in the received address 52. The foregoing is achieved by asserting fill signals 152 and 153 while deasserting signals 154 and 155 when the most significant bit of the offset 57 is deasserted. If multiple ways of the identified set are allocated to the lower way line halves in other embodiments, then the fill logic 122 may employ a replacement algorithm to select one of these ways for the storage of the way line half. By implementing the foregoing techniques for fill operations, only upper way line halves are stored in data array 117, and only lower way line halves are stored in data array 116. Thus, each memory line, representing only a portion (i.e., half in the instant embodiment) of a way line, is partially associative within the set identified by the memory line's address. When the cache 25 receives a read request from processor 22 while operating in the half way line mode, the tag compare logic 131 and 133 output signals 165 and 175 according to the techniques described above. The hit logic 125, however, automatically deasserts at least one of the signals 169 or 179 depending on whether the requested data is in the upper or lower half of a way line. In this regard, if the most significant bit of the offset 57 is asserted, then the requested data is in the upper half of a way line. In such an example, the hit logic 125 automatically deasserts signal 169 such that a cache hit for data array 116 does not occur. Note that data array 116 does not store upper way line halves in the current mode of operation, and it is, therefore, not possible for this array 116 to be storing the requested data. Thus, deasserting signal 169 ensures that a false cache hit for data array 116 does not occur. If the most significant bit of the offset 57 is deasserted, then the requested data is in the lower half of a way line. In such an example, the hit logic 125 automatically deasserts signal 179 such that a cache hit for data array 117 does not occur. Note that data array 117 does not store lower way line halves in the current mode of operation, and it is, therefore, not possible for this array 117 to be storing the requested data. Thus, deasserting signal 179 ensures that a false cache hit for data array 117 does not occur. In the half way line mode of operation, the multiplexor 181 selects one of the way lines from data arrays 116 and 117 based on the signals 169 and 179 in the same manner as described above for the full way line mode of operation. Further, the multiplexor 184 selects, based on the offset 57, the requested data from the output of multiplexor 181, and the multiplexor 184 transmits the requested data to the processor 22. FIG. 5 depicts exemplary circuitry that may be used to implement the hit logic 125. The circuitry of FIG. 5 comprises an inverter 252, two OR gates 255 and 257, and two AND gates 262 and 264. The mode signal 137 is provided as an input to OR gates 255 and 257. Further, the most significant bit (MSB) of the offset 57 is provided as an input to OR gate 257 and is provided as an input to OR gate 255 after passing through the inverter 252. The output of OR gate 255 is provided as an input to AND gate 262 along with the output signal 165 of tag compare logic 131 (FIG. 4), and the output of OR gate 257 is provided as an input to AND gate 264 along with the output signal 175 of tag compare logic 133 (FIG. 4). The AND gates 262 and 264 respectively output the signals 169 and 179 used to control the multiplexor 181 (FIG. 4). According to the circuitry shown by FIG. 5, the most significant bit of the offset 57 has no effect on the output of AND gates 262 and 264 when the cache 25 is operating in the full way line mode (i.e., when the mode signal 137 is asserted). In such a mode of operation, the signal 169 output by AND gate 262 matches the input signal 165 from tag compare logic 131, and the signal 179 output by AND gate 264 matches the input signal 175 from tag compare logic 133. However, in the halfway line mode, the most significant bit of the offset 57 controls which of signals 169 and 179 may be asserted and, therefore, indicate a cache hit. In this regard, if the most significant bit of the offset 57 is asserted, then only the signal 179 associated with the data array 117 storing upper way line halves may be asserted and, therefore, indicative of a cache hit. However, if the most significant bit of the offset 57 is deasserted, then only the signal 169 associated with the data array 116 storing lower way line halves may be asserted and, therefore, indicative of a cache hit. An exemplary architecture and functionality of the cache 25 while servicing a read request during the half way line mode of operation will now be described with particular reference to FIGS. 6 and 7. For illustrative purposes, assume that way 0 is allocated to lower way line halves and that way 1 is allocated to upper way line halves, as described above. Further assume that a read request from processor 22 requests data that is within an upper half of a way line, referred to as “identified way line,” stored in one of the memory blocks 49. Also assume that the requested data is stored in way 1 when the cache 25 receives the read request from processor 22. In response to the read request, the cache 25 determines whether there is a cache hit or, in other words, determines whether the requested data is available in the cache 25, as shown by block 312 of FIG. 6. To determine whether there is a cache hit, the cache 25 performs the process depicted by FIG. 7 for each way 0 and 1. Note that signal 169 of FIG. 4 indicates whether there is a cache hit associated with data array 116, and signal 179 indicates whether there is a cache hit associated with data array 117. Thus, for way 0, the index 56 of the address 52 in the read request is provided to tag array 114. The tag array 114 retrieves and outputs to tag compare logic 131 the tag stored in the entry identified by the index 56, as indicated by block 316 of FIG. 7. The tag compare logic 131 then compares the retrieved tag to the tag 55 of the address 52 included in the read request, as indicated by block 319. If the two tags do not match, then data array 116 is not storing data from the identified way line. Thus, a no tag hit indication is provided as shown by blocks 325 and 327. In particular, the tag compare logic 131 deasserts signal 165, which forces signal 169 to be deasserted. If the two tags match, then a “yes” determination is made in block 325, and the data array 116 is storing data from the identified way line. However, since data array 116 is allocated to lower way line halves, data array 116 is not storing the requested data. In this regard, the data array 116 is storing the lower half of the identified way line, and the requested data is within the upper half of the identified cache. Moreover, in block 332, the hit logic 125 determines whether the most significant bit of the offset 57 is asserted. Since the requested data is in the upper half of the identified way line, the most significant bit of the index 57 is indeed asserted. Thus, hit logic 125 provides a cache hit indication for way 0 only if the data array 116 is allocated to upper way line halves, as shown by blocks 335 and 337. However, since data array 116 is allocated to lower way line halves, a “no” determination is made in block 335, and block 321 is, therefore, performed instead of block 337. Thus, the hit logic 125 deasserts signal 169 thereby indicating that data array 116 and, therefore, way 0 are not associated with a cache hit. Note that if the most significant bit of the index 57 had been deasserted, then a cache hit indication for data array 116 and, therefore, way 0 would have been provided by asserting signal 169, as indicated by blocks 341 and 337. For way 1, the index 56 of the address 52 in the read request is provided to tag array 115. The tag array 115 retrieves and outputs to tag compare logic 133 the tag stored in the entry identified by the index 56, as indicated by block 316 of FIG. 7. The tag compare logic 133 then compares the retrieved tag to the tag 55 of the address 52 included in the read request, as indicated by block 319. Since the requested data is in the data array 117, the two tags should match. Thus, the tag compare logic 133 makes a “yes” determination in block 325 and asserts signal 175, which enables the signal 179 to be asserted by the hit logic 125. Moreover, in block 332, the hit logic 125 determines whether the most significant bit of the offset 57 is asserted. As indicated above, the most significant bit of the index 57 is indeed asserted since the requested data is in the upper half of the identified way line. Since data array 117 is allocated to upper way line halves, a “yes” determination is made in block 335, and block 337 is, therefore, performed instead of block 321. Thus, the hit logic 125 asserts signal 179 thereby indicating that data array 117 and, therefore, way 1 are associated with a cache hit. Since at least one of the data arrays 116 or 117 is associated with a cache hit, a “yes” determination is made in block 312 of FIG. 6. Accordingly, the requested data is retrieved from the data array 117 associated with the cache hit, as indicated by block 352 of FIG. 6. In this regard, the index 56 is provided to the data array 117. The data array 117 retrieves and transmits to multiplexor 181 the data in the data array entry identified by the index 56. Note that this data includes the lower half of the identified way line. Since signal 179 is asserted, as described above, the multiplexor 181 selects the data output by the data array 117 and transmits this data to the multiplexor 184. In block 355, the multiplexor 184 uses the offset 57 to select only the data byte or bytes requested by the read request and to transmit this data byte or bytes to the processor 22. Thus, the requested data is provided to the processor 22 without having to submit a read request to memory system 42. Note that if the requested data had not been stored in the cache 25, then a cache hit indication would not have been provided for any of the data arrays 116 and 117. In such an example, a “no” determination would have been made in block 312 of FIG. 6, and the requested data would have been retrieved from the memory system 42, as indicated by block 363. Further, a fill operation would have preferably been performed for the lower half of the identified way line, as indicated by block 366, in order to store the lower way line half in the cache 25. However, performing a fill operation for the upper half of the identified way line would not be necessary unless data within the upper way line half is actually requested by a subsequent read request. It should be noted that, in an exemplary embodiments described above, the system 20 has generally been described as accommodating memory line sizes of n or n/2 bytes. However, the system 20 may be configured to accommodate any number of memory line sizes. For example, the system 20 can be configured to accommodate n, n/2, and n/4 byte memory lines sizes. In such an embodiment, one-fourth of the ways of cache 25 may be allocated to a different way line portion when the system 20 is accommodating n/4 byte memory line sizes, and the most significant two bits of the offset 57 may be used to select the appropriate way to which to store a way line portion received from system interface 36. Further, the mode signal 137 may comprise at least two bits to indicate whether the system 20 is operating in a mode for accommodating n, n/2, or n/4 byte memory line sizes.
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<SOH> SUMMARY OF THE DISCLOSURE <EOH>Generally, embodiments of the present disclosure provide systems and methods capable of adaptively accommodating various memory line sizes. A cache memory system in accordance with an exemplary embodiment of the present disclosure comprises cache memory and cache logic. The cache memory has sets of ways. The cache logic is configured to request a memory line in response to a cache miss, and the memory line represents a portion of a way line. The cache logic is configured to select one of the ways based on which portion of the way line is represented by the memory line. The cache logic is further configured to store the memory line in the selected way. A cache memory system in accordance with another embodiment of the present disclosure comprises cache memory, compare logic, and hit logic. The cache memory has a tag array and a data array, and the tag compare logic is configured to receive a tag of an address associated with a read request and a tag retrieved from the tag array based on an index of the address. The tag compare logic is further configured to compare the received tags and to transmit a hit signal based on a comparison of the received tags. The hit signal indicates whether an entry of the data array is storing data from a memory block identified by the tag and index of the address. The hit logic is configured to manipulate the transmitted hit signal based on whether the data from the memory block includes data requested by the read request. A cache memory system in accordance with yet another embodiment of the present disclosure comprises cache memory and cache logic. The cache memory has sets of ways, and the cache logic is capable of operating in at least a first mode of operation and a second mode of operation. The cache logic is configured to receive a first plurality of memory lines when operating in the first mode of operation and to receive a second plurality of memory lines when operating in the second mode of operation. Each of the first plurality of memory lines has a first size, and each of the second plurality of memory lines has a second size. The cache logic is further configured such that each of the first plurality of memory lines is assigned to and fully associative within a respective one of the sets and such that each of the second plurality of memory lines is assigned to and partially associative within a respective one of the sets.
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20040702
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20090602
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20060105
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67550.0
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G06F1200
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THAMMAVONG, PRASITH
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CACHE MEMORY SYSTEM AND METHOD CAPABLE OF ADAPTIVELY ACCOMMODATING VARIOUS MEMORY LINE SIZES
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UNDISCOUNTED
| 0
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ACCEPTED
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G06F
| 2,004
|
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10,883,961
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ACCEPTED
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Process and device for biological treatment of a suspension in a bioreactor with integrated hydraulic top scum treatment
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A process and a device for biological treatment of a suspension in a bioreactor, wherein the suspension is circulated, at least some of the suspension is routed through a vertically aligned guide zone in the bioreactor so that a vertical flow of the suspension is produced. The top scum in the area of the suspension fill level is controlled by feeding a fluid, especially in the form of a free liquid jet, into the bioreactor via at least one nozzle at the fill level, such that the surface of the suspension and/or the top scum floating on the surface of the suspension is forced into rotary flow.
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1. In a process for biological treatment of a suspension in a bioreactor in which to circulate the suspension, at least some of the suspension is routed through a vertically aligned guide zone so that a vertical flow of at least a portion of the suspension is produced, which flow proceeds into the area of the suspension fill level or from the area of the suspension fill level, the improvement comprising feeding a fluid in the area of the suspension fill level so as to cause rotary flow of the surface of the suspension and/or of the top scum floating on the surface of the suspension. 2. A process according to claim 1, wherein the fluid is fed into the bioreactor via nozzles that are mounted tangentially on the periphery of the tank. 3. A process according to claim 1, wherein the fluid fed to the area of fill level is suspension that is suctioned off from the bioreactor. 4. A process according to claim 2, wherein the nozzles are supplied with fluid at different times. 5. A process according to claim 2, wherein the nozzles are operated with a common pump and are successively supplied from the latter by means of cyclic switching. 6. A process according to claim 1, wherein at least a portion of the top scum floating on the surface of the suspension in the rotary flow is removed via at least one top scum outlet on the inside wall of the bioreactor in the area of the suspension fill level. 7. A process according to claim 6, wherein the top scum is washed into the top scum outlet by means of a fluid supplied in the vicinity of the top scum outlet. 8. A process according to claim 7, wherein fluid is fed to the suspension fill level at opposite side of the reactor periphery from the top scum outlet. 9. A process according to claim 7, wherein fluid is fed via a nozzle that is provided in the vicinity of the top scum outlet with a momentum such that the top scum is conveyed into the top scum outlet. 10. A process according to claim 1, wherein the fluid is fed with a flow velocity of 10 to 15 m/s. 11. A process according to claim 1, wherein the fluid is fed with a volumetric flow rate of 300 to 600 m3/h. 12. A bioreactor for biological treatment of a suspension comprising in the interior of the bioreactor guide means with a vertical alignment for circulating the suspension, and at least one nozzle for feeding a fluid into the bioreactor in the area of the suspension fill level. 13. A bioreactor according to claim 12, wherein the at least one nozzle is supplied with the fluid via a feed line that is connected to the interior of the bioreactor via a pump. 14. A bioreactor according to claim 12, wherein several nozzles are distributed in the area of the suspension fill level on the periphery of the bioreactor. 15. A bioreactor according to claim 12, further comprising a top scum outlet that is attached to the inside wall of the bioreactor in the area of the suspension fill level. 16. A bioreactor according to claim 15, further comprising a nozzle for feeding a fluid in the vicinity of the top scum outlet. 17. A bioreactor according to claim 15, further comprising a nozzle for feeding a fluid on the side of the bioreactor opposite the top scum outlet. 18. A bioreactor according to claim 12, wherein the at least one nozzle has a diameter of 50-120 mm.
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CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of U.S. Ser. No. 10/740,690 filed Dec. 23, 2003 and claims priority to German Application 103 58 399.8. This application is also related to a concurrently filed application entitled “Process And Device For Biological Treatment Of A Suspension In A Bioreactor With Integrated Hydraulic Bottom Layer Removal” Ser. No. ______ (Attorney Docket No. LINDE-0615 P1) by the identical inventors. The invention relates to a process for biological treatment of a suspension in a bioreactor in which to circulate the suspension, at least some of the suspension is routed through a vertically aligned guide zone so that a vertical flow of at least a portion of the suspension is produced, which flow extends into the area of the suspension fill level or proceeds from this area. The invention also relates to a device for carrying out the process. Processes for biological treatment of suspensions are, e.g., aerobic or anaerobic processes for biological treatment of waste water, sewage sludge or waste, in which the biodegradable substances contained in the suspension are decomposed by microorganisms. Processes for biogas recovery are defined below as the anaerobic treatment of suspensions containing biodegradable materials, especially the fermentation of waste or sludge digestion in the treatment of sewage sludge. Here, the biodegradable materials that are also called fermentation media are fermented into biogas in a bioreactor called a fermentation reactor with the exclusion of air. Often mechanical stirring systems or hydraulic recirculation systems are used to thoroughly mix the fermentation medium in the fermentation reactor. Injecting gas into the vicinity of the bottom of the fermentation reactor is also used in various ways. In so-called loop reactors, a gas is injected into a central guide pipe located within the fermentation reactor, by which the fermentation medium is drawn into the guide pipe. In this way, e.g., the fermentation medium can be conveyed by the guide pipe from the vicinity of the bottom of the fermentation reactor to the surface of the fermentation medium contained in the fermentation reactor. Thus, at least most of the fermentation medium can be circulated in the fermentation reactor. Such a system is described in, e.g., DE 197 25 823 A1. In addition to the important feature that there are no moving parts in the fermentation reactor, this system offers still other advantages. For example, low-gradient, thorough mixing is achieved via the vertical loop. Moreover, the possibility of integrating a heat exchanger into the fermentation reactor in the form of a double-jacketed pipe through which hot water flows is offered. By blowing gas into the guide pipe, so-called loop flow forms, which has associated with it some surface surge flow formation and turbulent bottom mixing, where the surface flow is pointed radially outward, by which the formation of surface scum is controlled. As a result of the defined flow conditions near the bottom which provide sediment transport in the direction of the central bottom outlet, finally the formation of sediment deposits commonly is also prevented. In practical operation, however, it has been shown that for special sludge and waste qualities supplied to the fermentation reactor in a system-specific manner, surface layer and sediment problems can occur that require additional control measures. Special type of sludges may have a higher content of detergents and fine-fibrous plastic and cellulose particles, which usually result from community waste water treatment or special commercial organic residues, and/or maybe more highly viscous sludges, and/or have solid particles that are larger depending on origin, for example, may contain glass fragments and/or other irregularly shaped inert particles. For the initial materials, Rotational skimming can take place with collection in the outer area of the fermentation surface in the reactor, where the radially decaying turbulence is no longer sufficient for bottom mixing. For sediments that are dissimilar to sand (rounded quartz grains), entanglement of the particles by their irregular fracture edges can occur; this means increased resistance to hydraulic transport to the center bottom discharge point. Accordingly, an aspect of the invention is a process and apparatus of the initially mentioned type wherein top scum problems are reliably ameliorated. Upon further study of the disclosure, other aspects and advantages of this invention will become apparent. According to a process aspect of a invention, a fluid is passed in the area of the suspension fill level, so that the surface of the suspension and/or the top scum floating on the surface of the suspension is forced into rotary flow. Here, the fluid is fed into the bioreactor via a nozzle, preferably as a free liquid jet. The basic idea of the invention, therefore, comprises superimposing a hydraulic jet system on the gas-induced loop reactor principle. In this way, the process-engineering advantages of a loop reactor with a guide pipe and gas injection can be used and at the same time problem cases that occur depending on the media are controlled without significantly increasing the addition of energy to the bioreactor system. A free liquid jet injected into the bioreactor in the area of the suspension fill level causes rotation of the liquid mass near the surface. Rotary flow around the reactor center is formed from liquid jets emerging from nozzles placed substantially tangentially around the periphery of the bioreactor in the area of the fill level. According to the invention, intensified top scum treatment takes place via a nozzle system that is located near the surface on the periphery of the tank. Here, fluid that is suctioned off from the bioreactor is fed into the bioreactor in part or in a time sequence via at least one nozzle that is provided in the area of the suspension fill level such that the surface of the suspension and/or the top scum floating on the surface of the suspension is forced into rotary flow. Preferably, the fluid is fed into the bioreactor via nozzles that are located tangentially on the periphery of the tank. Here, advantageously, a portion of the suspension that is suctioned off from the bioreactor is used as a fluid. The nozzles are preferably supplied with fluid at different times. Especially preferably the nozzles are operated with a common pump and successively supplied from the latter by means of cyclic switching. The top scum and foam particles that accumulate in the vicinity of the periphery of the tank have the tendency to stick together and compact together over time. These particles are preferably therefore continually wetted and/or kept slippery, and are preferably agitated when they compact together. Gas bubbles adhesively adhering to the particles are preferably eliminated in order to reduce buoyancy. Optionally, the particles are deflected into the vicinity of the surface. Complete control over the entire reactor periphery is not technologically feasible because steel fermentation reactors, for example, are generally not designed for a fill level in the area of the roof slope in terms of strength. Thus, the free liquid surface in such reactors corresponds to the cross-sectional area of the cylindrical part of the reactor. According to an especially preferred embodiment of the invention, that the top scum, that has been pushed together into a ring by the radial surface flow from the guide zone to the periphery of the tank, is exposed hydraulically to free liquid jets from preferably at least two nozzles located tangentially on the periphery of the tank. These jets force the ring of top scum into rotation by means of transferred pulses caused by the successive cyclic switching of the at least two nozzles. In doing so, the top scum ring runs through the jet zones and is wetted and agitated there in the desired manner. The top scum outlet attached radially (i.e., rectangular to the inner tank wall on the radius line from wall to tank center) to the inside wall of the tank with a drop pipe, whereby the scum can be removed at the level of the liquid surface, feasibly enables removal of floating material that can no longer be stirred into the suspension. The conditions can be adjusted by a change in the fill level in the bioreactor such that either the top scum rotates over the outlet or the material is pushed into the outlet box in batches. Preferably a first nozzle is located at a distance in front of the top scum outlet such that it washes the material into the outlet box with sufficient momentum. Preferably, there is a second nozzle opposite the first nozzle and outlet box that provides for movement and wetting. Advantageously, operation of the two nozzles likewise takes place cyclically. Preferably, the fluid is fed into the bioreactor with a flow velocity of 10 to 15 m/s and a volumetric flow rate of 300 to 600 m3/h. In other aspects, the reactor according to the invention also contains a biogas recovery system. In yet further aspects, the invention also relates to a device for biological treatment of a suspension with a bioreactor, the interior of which contains a guide means that extends below or into the area of the suspension fill level with a vertical alignment for circulating the suspension. The apparatus according to the invention comprises at least one nozzle for feeding a fluid into the bioreactor in the area of the suspension fill level. The nozzle can advantageously be supplied with the suspension via a feed line that is connected to the interior of the bioreactor and via a pump. Preferably, there are several nozzles distributed in the vicinity of the surface on the periphery of the bioreactor, advantageously with a tangential alignment. Here, the nozzles are preferably connected to a common pump. The nozzle advantageously has a diameter of 50 to 120 mm. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. The invention will be explained in more detail based on an embodiment that is shown diagrammatically in the figure. BRIEF DESCRIPTION OF THE DRAWINGS Various features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: FIG. 1 shows a plant with a bioreactor according to the invention. FIG. 2 shows a bioreactor according to the invention. FIG. 3 shows a bottom fluid circulating nozzle viewed from the side. FIG. 4 shows a more detailed illustration of the nozzle from FIG. 3. FIG. 5 shows a bottom fluid circulating nozzle viewed from the top. DETAILED DESCRIPTION OF THE DRAWING FIG. 1 shows a plant for fermentation of wet garbage, for example. The wet garbage is processed in pretreatment steps, not shown in the figure, whereby pulp or hydrolysate is formed. The pulp or hydrolysate is supplied to the bioreactor labeled as the fermentation reactor 2 via a line 1 as a suspension called the fermentation medium. In the fermentation reactor 2, methanation of the pulp or hydrolysate is carried out. To do this, the fermentation reactor 2 is kept under anaerobic conditions, and the contents of the fermentation reactor are circulated. The anaerobic biomass contained in the fermenting pulp and hydrolysate converts the organic substances partially into carbon dioxide and methane. The resulting biogas is drawn off from the fermentation reactor 2 via the line 3. Since the pulp or hydrolysate also contains sulfur compounds, H2S would also be formed without further measures and would be found again ultimately in the biogas. In order to minimize the undesirable H2S portions in the biogas, the entire contents of the fermentation reactor are transported through an oxygen-containing zone with adequate contact time between the oxygen-containing gas and fermentation medium. For this purpose, the fermentation reactor 2 is made as a loop reactor with an inside loop in the form of a centrally and vertically arranged guide pipe 5 that acts as the oxygen-containing zone. Biogas is branched off from the biogas discharge line 3 via the biogas branch line 6 and pumped into the lower part of the interior of the guide pipe for use as a propellant gas. As a result of the decrease in the density of the mixture in the guide pipe 5 and the gas buoyancy force, the fermentation medium is conveyed through guide pipe 5 from bottom to top. In doing so, the hydraulic conditions are set by choosing the guide pipe geometry and the injected biogas flow, such that the entire contents of the fermentation reactor are preferably pumped at least twice per hour through the guide pipe 5. Air is metered into the inner ascending flow of the guide pipe 5 by means of an air feed line 7 in quantitative ratios such that the fermentation medium adequately acquires oxygen contact during passage through the guide pipe 5 in order to limit H2S formation in the metabolic processes in the desired manner. At the same time, the oxygen is decomposed biochemically to such an extent that there are no longer any oxygen portions that adversely affect the process in the biogas. The air demand can thus be minimized such that the nitrogen in the biogas does not lead to a significant diminishment of gas quality for further caloric use. To maintain an operating temperature that is optimum for biological treatment of the fermentation medium, the guide pipe 5 is made to be heated. To do this, the guide pipe 5, for example, provided with a double-walled jacket that has a feed line 8 and discharge line 9 for the heating water. In addition, the contents of the fermentation reactor can be temperature-treated by means of an outside heat exchanger (not shown) through which heating water flows. To control the problem cases that occur specific to the media, especially sediment problems that arise for special sludge and waste qualities, a hydraulic jet system is superimposed on the gas-induced loop reactor principle. In this way, the process-engineering advantages of the loop reactor with a guide pipe 5 and gas injection 6 can be used and at the same time problems that arise specific to the media are solved without significantly increasing the addition of energy into the fermentation system. For this purpose, the fermentation medium is drawn off from the fermentation reactor 2 via line 15 and pump 16 and supplied to a nozzle 11 via line 12. The fermentation medium as a free liquid jet is fed into the fermentation reactor 2 via the nozzle 11 at a nozzle velocity of 10 to 15 m/s and a volumetric flow rate of 300 to 600 m3/h in the area near the bottom. In fermentation reactors with up to 8000 m3 of reaction volume and diameters of up to 24 m, the necessary pulsed flow is produced in this way in order to have the liquid mass near the bottom rotate at roughly 0.3 m/s to 1.0 m/s, preferably, 0.5 m/s near the tank wall. Here, the nozzle 11 that has a diameter of 50 to 120 mm, depending on the tank size and the process parameters, is offset by 400 to 600 to radial flow in order to induce torque. A tilt angle of the nozzle 11 to the horizontal of 0 to 100, for example, >0 to 10°, compensates for the media-induced buoyancy forces in the jet field. In practice, between two and five nozzles are arranged at corresponding distances on the periphery over the entire fermentation reactor tank circumference, depending on the reactor size. For the sake of clarity, the figure shows only one nozzle 11. All of the installed nozzles can be connected to a single pump, specifically the pump 16, and successively supplied from the latter by means of cyclic switching of the series. This makes possible an efficient and low-maintenance mode of operation. In order to control top scum problems, a branch line 14 leads from the pump 16 to a nozzle 13 that is located on the fermentation reactor tank circumference near the surface of the suspension. The hydraulic connection of this nozzle 13 takes place via the pump 16 when the on cycles for the top nozzle are such that for each such on cycle one or two additional on cycles can be assigned to the bottom nozzles. When the nozzle 13 is working frequently because of the nature of the media, a separate pump should be preferred. As with the nozzles 11 located in the vicinity of the bottom, it is also recommended that there be several nozzles 13 located near the surface of the suspension. The direction, i.e., the angle(s) in which the nozzles point, of nozzles 13 are preferably set in a similar manner to the direction of nozzles 11. For the sake of clarity, however, only one nozzle 13 is shown in the FIG. 1. In the above description, the bottom part of the reactor is below the bottom of the guide pipe 5. FIG. 2 illustrates in more detail an embodiment of the fermentation reactor described above. For sake of clarity, the numbers identifying corresponding elements in the figures are numbered identically. This fermentation reactor 2 has forced guidance of sediment and underbody removal. Forced guidance is achieved by a bottom circulation system that produces horizontal rotary flow in the bottom area of the reactor. As described above, the fermentation medium/material is drawn off from the fermentation reactor via line 15 and pump 16 and supplied to a nozzle 11 via line 12. To remove sediment, or optionally sediment with fermentation material, e.g., by underbody removal, the reactor contains a central bottom outlet 17. This outlet leads to a pipe which, once in the horizontal direction, is preferably an elbow-free pipe. The pipe crosses under the reactor to carry materials, for example, sediment, out from outlet 17. The height of the cylindrical portion of the reactor, i.e., not including the top and bottom portions where the diameter narrows, is typically chosen to be 1.1 to 1.3 times more than the reactor's diameter, but is not restricted. For example, the height may be up to 2 times the reactor's diameter for certain applications. The ratio of the diameter of the reactor to the diameter of the guide pipe (5) is typically about 4:1 to 10:1. The bottom of the guide pipe is positioned about 1.0 to 1.5 meters above the central bottom outlet 17. The top of the guide pipe is positioned about 1.0 to 1.5 meters below the minimum level of fermentation material. Pipe 6 through which biogas is charged into the guide pipe may be immersed anywhere from about 6 to 14 meters below the level of fermentation material. The top and bottom parts of the reactor are structured according to design conditions and are not restricted as illustrated herein. The shape of the top part, for example, can also be a curved top form as illustrated by the dashed line in FIG. 2. The bottom part of the reactor has a central flat floor surface 18. This surface has a diameter that is typically 4 to 8 times less than the diameter of the reactor. The top part of the reactor has a central service platform 19 that has a diameter that is 4 to 8 times less than the reactor's diameter. The sloped portion of the bottom 21, between the central flat floor 18 and the cylindrical portion of the reactor, and the sloped portion of the top 20, between the central service platform 19 and the cylindrical portion of the reactor, respectively, are each, independently, sloped at an angle of 0 to 20°, e.g. >0 to 20°. The bottom portion 21 is preferably integrated with the slope of the concrete floor, which accordingly has a complementary slope of 0 to 80°. The space or gas volume (gas space) above the liquid in the tank is about 4 to 10% of the liquid volume. The pressure in the gas space is less than or equal to about 100 mbar. The specific reactor illustrated has a nominal volume of 2376 m3 with a maximum liquid volume of 2231 m3, and is operated such that it has a preferred hydraulic dwell time of 20 days for the fermentation of communal sewage sludge. In this specific reactor embodiment, the slope of the top part 20 is 12°, and the slope of the bottom part 21 is 10°. The diameter of the cylindrical portion of the reactor is about 13.4 meters. The central pipe has an inner diameter of 2.5 meters and a length of 12.0 meters. Pipe 6 delivering biogas is immersed about 12 meters into the fermentation material. Platform 19 has a diameter of 2.25 meters. The inlet of the bottom circulation system, e.g., to pipe 15, is 0.5 meters, and the outlet of said system, e.g., nozzle 11, is 0.7 meters above the bottom of the cylindrical portion of the fermentation reactor. The centrically flat floor and the centric service platform are each about 1.18 meters above and below, respectively, the cylindrical portion of the reactor. In this embodiment, the level of fluctuation for the fermentation material is about 0.78 meters, with the maximum level being about 0.58 meters below the top of the cylindrical portion of the reactor. FIG. 3 illustrates a side view of the bottom circulation system in more detail. The outlet of said system is equipped with nozzle 11 through which material from the fermentation reactor is pumped through to produce a horizontal rotary flow of the material in the reactor. For example, the nozzle in this embodiment produces a force of momentum of 1.0 kN. FIG. 4 illustrates a more detailed view of a nozzle of the bottom circulation system. In this embodiment, the nozzle is directed at an angle of 10 degrees below horizontal. FIG. 5 illustrates a top view of the bottom circulation system in more detail. The nozzle is directed 40-60 degrees from the radius, i.e., the line from the axis of the guide pipe 5 to the wall of the reactor. The entire disclosures of all applications, patents and publications, cited herein and of corresponding German Application No. 103 58 400.5 filed on Dec. 23, 2002, are incorporated by reference herein. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. In the above description, the “area of the suspension fill levels includes the suspension surface and generally some centimeters above and below the surface, for example, above and below 30 or 20 or 10 or 5 or 3 centimeters from the surface, depending on the size of the reactor. The entire disclosures of all applications, patents and publications, cited herein and of corresponding German Application No. 103 58 399.8 filed on Dec. 23, 2002, are incorporated by reference herein. From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
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<SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>Various features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: FIG. 1 shows a plant with a bioreactor according to the invention. FIG. 2 shows a bioreactor according to the invention. FIG. 3 shows a bottom fluid circulating nozzle viewed from the side. FIG. 4 shows a more detailed illustration of the nozzle from FIG. 3 . FIG. 5 shows a bottom fluid circulating nozzle viewed from the top. detailed-description description="Detailed Description" end="lead"?
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20040706
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20070306
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20050210
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75148.0
| 0
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BARRY, CHESTER T
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PROCESS AND DEVICE FOR BIOLOGICAL TREATMENT OF A SUSPENSION IN A BIOREACTOR WITH INTEGRATED HYDRAULIC TOP SCUM TREATMENT
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
| 2,004
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10,884,010
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ACCEPTED
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System and method for electronically managing remote review of documents
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A system and method are provided for electronically managing remote review of documents that are stored on a central repository. The remote review system advantageously enables a remote reviewer, lacking repository access, to remotely review and record decisions in respect to documents stored in the repository and then electronically integrate those remotely made decisions back into the repository. In this way, the inventive system and method promotes efficiency and consistency in responding to document requests for legal purposes.
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1. A system for electronically managing remote review of documents for legal purposes comprising: a repository of electronically stored documents; an export tool for exporting one or more of the documents for remote review by a reviewer lacking access to the repository; and an import tool for importing decisions of the reviewer back into the repository thereby enabling electronic integration of remotely made decisions into the repository. 2. The system of claim 1 wherein the system further includes an electronic decision tool for remote use by the reviewer, the decision tool enabling the reviewer to electronically record decisions about the documents. 3. The system of claim 2 wherein the electronic decision tool contains electronic copies of the documents for review thereby enabling the reviewer to electronically review the documents with the decision tool without having access to the documents in the repository. 4. The system of claim 2 wherein the electronic decision tool contains a list of decisions requested of the reviewer for each of the documents. 5. The system of claim 2 wherein the electronic decision tool contains a list of decisions requested of the reviewer for each of the documents and a selection tool for electronically recording the requested decisions thereby enabling the reviewer to electronically record the requested decisions into the decision tool for transmission back to the repository. 6. The system of claim 2 wherein the electronic decision tool contains a set of computer instructions for enabling the reviewer to electronically review the documents and electronically record decisions related to the documents and to create an electronic decisions file for return to a system user for electronic integration into the repository. 7. The system of claim 1 wherein the import tool identifies discrepancies between decisions requested of the reviewer and decisions made by the reviewer thereby enabling a system user to electronically identify discrepancies between the imported decisions and the decisions requested of the reviewer. 8. The system of claim 1 wherein the export tool enables a system user to transmit electronic copies of the documents from the repository to the reviewer. 9. The system of claim 1 wherein the repository contains prior decisions on the documents and wherein the import tool electronically identifies conflicts between the prior decisions and the review decisions being imported into the repository thereby enabling a system user to easily identify conflicts between the prior decisions and the review decisions. 10. The system of claim 1 wherein the export tool is for identifying one or more decisions requested of the reviewer for the documents and the import tool is for enabling a system user to identify imported decisions from the reviewer having discrepancies with requested decisions. 11. The system of claim 10 of wherein the discrepancies include one or more of the following: failing to make the requested decisions, and partially making the requested decisions. 12. The system of claim 1 wherein the repository contains prior decisions for the documents and wherein the system includes a report tool for enabling a system user to identify conflicts between imported decisions from the reviewer and prior decisions in the repository. 13. The system of claim 1 wherein the system includes a report tool for enabling a system user to run one or more reports related to decisions on the documents. 14. A system for electronically managing remote review of documents for legal purposes comprising: a repository of electronically stored documents; an export tool for exporting one or more of the documents for remote review by a reviewer lacking access to the repository; and an import tool for importing decisions of the reviewer back into the repository and electronically associating decisions back to the documents, whereby remotely made review decisions can be electronically integrated into the repository without the reviewer having access to the repository. 15. A system for electronically managing remote review of documents for legal purposes comprising: a repository of electronically stored documents; an export tool for identifying one or more of the documents for remote review by a reviewer lacking access to the repository; a decision tool transmittable to the reviewer for remote stand-alone use, the decision tool including electronic copies of the documents for remote review and a set of computer instructions for the review thereby enabling the reviewer to electronically review documents and electronically record decisions about the documents in an electronic decision file; an import tool for importing the electronic decision file back into the repository, the import tool for electronically associating decisions with their respective documents in the repository, whereby documents can be remotely reviewed and remote decisions can be electronically integrated into the repository. 16. A system for electronically managing remote review of documents for legal purposes comprising: a repository of electronically stored documents; an export tool for identifying one or more of the documents for remote review by a reviewer lacking access to the repository; a decision tool transmittable to the reviewer for remote stand-alone use, the decision tool enabling the reviewer to electronically record decisions about the documents; and an import tool for importing decisions of the reviewer back into the repository as recorded by the reviewer via the decision tool, the import tool electronically associating decisions with their respective documents, whereby remotely made decisions can be electronically integrated into the repository without the remote reviewer having access to the repository. 17. A system for electronically managing remote review of documents for legal purposes comprising: a repository of electronically stored documents, and an electronic decision tool containing a copy of the electronically stored documents from the repository and a set of computer instructions for enabling the reviewer to electronically review the documents and electronically record decisions related to the documents in the decision tool, the decision tool for enabling the remote reviewer to create an electronic decision file for return to a system user for electronic integration into the repository. 18. The system of claim 17 wherein the system includes an export tool for exporting documents and creating the decision tool; and an import tool for importing the electronic decision file into the repository thereby enabling electronic review and integration of remotely made decisions into the repository. 19. The system of claim 17 wherein the decision tool contains a list of requested decisions from the remote reviewer and the system further includes an import tool enabling the system user to identify discrepancies between decisions requested of the reviewer in the decision tool and decisions made by the reviewer in the decision file thereby enabling the system user to electronically recognize discrepancies between the imported decisions and the decisions requested of the reviewer. 20. The system of claim 17 wherein the repository contains prior decisions on the documents and wherein the system includes an import tool for electronically identifying conflicts between the prior decisions and the review decisions imported from the decision file thereby enabling the system user to identify conflicts between the prior decisions and the review decisions. 21. The system of claim 20 wherein the system includes a resolution tool for enabling the system user to electronically resolve conflicts between the imported and prior decisions on the documents. 22. The system of claim 17 wherein the electronically recorded decisions include one of more of the following: produce, do not produce, protect, do not protect, propose privilege, and do not propose privilege. 23. A method for electronically managing remote review of documents for legal purposes, the method comprising: having one or more documents electronically stored in a repository; transmitting one or more copies of the electronic documents stored in the repository for a remote review; receiving one or more electronic review decisions on the documents in response to the remote review; and associating the electronic review decisions with the electronic documents stored in the repository. 24. The method of claim 23 wherein the method further includes transmitting copies of the documents to multiple reviewers for multiple review decisions. 25. The method of claim 23 including the repository having prior decisions stored therein and further including the step of electronically identifying conflicts between the prior decisions and the review decisions when the review decisions are being associated to the electronic documents stored in the repository. 26. The method of claim 23 further including the repository having prior decisions stored therein and further including the step of electronically identifying and resolving conflicts between the prior decisions and the received review decisions when the received review decisions are being associated with the electronic documents stored in the repository. 27. The method of claim 23 further including the step of identifying the requested remote review decisions and electronically identifying conflicts between the requested review decisions and the received review decisions from the reviewer. 28. The method of claim 23 further including the step of creating an electronic file identifying the documents for remote review and the decisions requested prior to transmitting the copies of the documents for remote review. 29. The method of claim 23 further including the step of electronically generating a status report on the remote review. 30. The method of claim 23 further including the step of generating a stand-alone set of computer instructions and files enabling the remote reviewer to electronically review documents, record decisions, and create a decision file being loadable into the repository and automatically associating the decisions with the electronic documents. 31. The method of claim 23 wherein the transmitting occurs at a first location and the remote review decisions are made at a second location. 32. The method of claim 23 wherein the transmission occurs by loading electronic copies of the documents onto a portable electronic storage device. 33. The method of claim 23 further comprising transmitting a decision tool with the copies of the documents, the decision tool including computer instructions for performing the remote review. 34. The method of claim 23 wherein the copy of the electronic documents includes a composite document and the decision is applied to one of the entire composite document or to a sub-component thereof.
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CROSS REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application Ser. No. 60/484,731 filed Jul. 3, 2003, and to U.S. Provisional Application Ser. No. 60/485,540 filed Jul. 8, 2003 which are incorporated by reference herein in their entirety. BACKGROUND OF THE INVENTION The present invention relates generally to a system and method for electronically managing remote review of documents for legal purposes. More specifically, the invention relates to an improved system and method for permitting stand-alone remote review of the documents while providing integration with a repository where the documents are electronically stored. Legal matters often involve massive volumes of information that must be organized and categorized in response to particular inquiries or issues, such as litigation pleadings, business transactions, government regulations, etc. The information is typically managed by a centralized organization, such as a legal department or group therein having document coordinators. Managing this documentary information often requires the review and input of persons remote or external to the centralized organization, such as other attorneys, business persons, or experts. The remote reviewers are typically requested to provide their opinion or decision on the categorization and treatment of the information for a particular legal matter, for example, such as to produce or not produce in response to a discovery request. At times there may be numerous remote reviewers reviewing numerous sets or subsets of documents whose decisions must be recorded. Also, conflicting decisions must be identified and reconciled with each other. It must also be ensured that the decisions of the remote reviewers are correctly matched back to the exact same document or version of the document for which their input is being sought. Existing methods for remote document review are time-consuming and not easily managed, tracked, recorded and reconciled. For example, the central document coordinator identifies a set of documents from the central repository needing external review. The external reviewers are typically located remote from the central document repository and are barred from accessing the repository in order to protect integrity of the documents stored in the repository. Thus, the coordinator prepares paper copies of the documents for review and sends them out to each of the remote reviewers for their stand-alone, external review. The coordinator manually ensures that the information sent for review is appropriately restricted, such as by removing privileged documents or portions thereof. The coordinator also has to somehow indicate the decisions that are requested for each of the documents, by manually creating a letter or other type of notice to the reviewer for the documents. The coordinator has no convenient way to track the status of the outstanding remote review requests. Under existing review methods, the remote reviewers return the paper documents together with a particular decision—such as produce, do not produce, mark as privileged, defer to another reviewer, etc . . . The returned documents are not necessarily in any particular order. As to each document, the coordinator must identify and resolve any conflicting decisions of different remote reviewers and any conflicts with prior decisions stored in the repository. This is typically done document by document—such as by manually sorting the documents or using a crude spreadsheet listing the documents and all of the current and prior decisions. The coordinator must also manually transfer any redactions and decisions onto the centralized document copy for the particular legal matter. Typically there is no historical record of decisions by the remote reviewer except in the paper file of that particular legal matter or as marked on the reviewer's document copy. Thus, the same or related reviewer may review the same documents for the same or a similar inquiry over and over again—sometimes even inadvertently being inconsistent with their prior decisions. Furthermore, other than the coordinator handling the specific legal matter, no other coordinator has ready access to decisions that have been made on a particular document by a remote reviewer except by finding and reviewing the paper documents for the other related legal matter. This can be especially problematic for documents that have been previously categorized as privileged. In some instances, due to the time-consuming tracking effort involved, the final decision of the last remote reviewer may not necessarily be logged back into the central repository and recorded with the particular document and legal matter. Thus, it is desirable to be able to easily identify, restrict, transmit, and track the documents sent to a remote reviewer, and to readily integrate the review decisions back into a centralized document repository. Further, it is desirable to easily match the decisions back to the correct document in the repository as well as to identify and reconcile any conflicting review decisions against prior decisions made as to the documents. It is also desirable to be able to easily identify any missing or otherwise deficient or incomplete decisions by the reviewers. Additionally, it is desirable to maintain the integrity of the documents stored in the centralized repository as well as easily record and store the historical review decisions in respect to the documents. BRIEF DESCRIPTION OF THE INVENTION According to one aspect of the invention, a system and method are provided for electronically managing the remote review of documents that are stored in a central repository. The inventive system and method advantageously enable a remote reviewer, lacking repository access, to remotely review and record decisions in respect to documents stored in the repository and then electronically integrating those remotely made decisions back into the repository. In another aspect of the inventive system and method for electronically managing the remote review of documents stored in a central repository, an export tool is provided for exporting a copy of one or more documents for remote review by a reviewer lacking access to the repository, and an import tool is provided for importing decisions of the remote reviewer back into the central repository in association with the documents reviewed. In a further aspect of the invention, a stand-alone decision tool enables a remote reviewer to electronically review documents from a central repository and record decisions about the documents for integration into the repository without having access to the repository. The electronic decision tool contains electronic copies of the documents for review thereby enabling the reviewer to electronically review the documents with the decision tool without having access to the documents in the repository. The electronic decision tool also contains a list of decisions requested of the reviewer for each of the documents and a selection tool for electronically recording the requested decisions thereby enabling the reviewer to electronically record the requested decisions into the decision tool for transmission back to the repository. In yet another aspect of the invention, the system includes an import tool that identifies discrepancies between decisions requested of the reviewer and decisions made by the reviewer as well as conflicts with prior decisions stored in the repository thereby enabling resolution of the discrepancies and conflicts as well as insuring consistency in handling of the documents. BRIEF DESCRIPTION OF THE DRAWINGS Referring to the exemplary drawings wherein like elements are numbered alike in the several FIGURES: FIG. 1 is a block diagram of an exemplary system for document review; FIG. 2 is a flow diagram of an exemplary system and method that may be utilized by exemplary embodiments of the invention; FIG. 3 is a flow diagram of a process for document review that may be utilized by exemplary embodiments of the present invention; FIG. 4 is a flow diagram of a process for exporting documents for review that may be utilized by exemplary embodiments of the present invention; and FIG. 5 is a flow diagram of a process for remotely reviewing documents utilized by exemplary embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION In accordance with exemplary embodiments, a Legal Support Application (LSA) 100, shown generally in FIG. 1, is a system that includes information and computer processes, software and/or programs to perform activities in support of legal matters. Legal matters often involve massive volumes of documentary information that must be organized, searched, reviewed, and categorized in response to particular inquiries or issues, such as litigation pleadings, business transactions, government regulations, and other legal issues. The LSA 100 is used to electronically store and manage documents 101 as well as other information regarding legal matters. For example, the LSA 100 may include a wide variety of functions and tools, including calendaring, docketing, general case matter information and other case management functions for the legal matters. Information in the LSA 100 includes the documents 101 that are electronically stored in a central data repository 108. As stated, the documents 101 are electronically stored in the central repository 108 and broadly include, without limitation, documents, drawings, test information, technical information, computer files, business records, and any other type of information that may be sought in a legal matter. The documents 101 may be electronically stored in the repository 108 in any suitable electronic form, such as digital files, image files, native files, and any combinations thereof. The documents 101 are preferably electronically stored in their entirety in the repository 108. While less desirable, some documents 101 may be electronically stored in the central repository 108 in a partial form. For example, large engineering drawings may be electronically stored using identifying information or partial images in the repository 108. It will also be appreciated that documents 101 may be multi-page documents, a single page document, a computer file, or any larger groupings, smaller divisions or any portions thereof that are identified as a document 101 in the central repository 108. It will further be appreciated that several related documents 101 may be grouped together as a composite document such that the composite document may be treated as a single grouped document or each as individual documents in the LSA 100 that can be separately or individually reviewed for document decisions. A detailed description of a commonly assigned invention related to electronic management of composite documents in LSA 100 is found in patent application docket number GP-303764 entitled “System and Method for Electronically Managing Composite Documents”, filed the same day as the present application, Jul. 2, 2004 and which is herein incorporated by reference in its entirety. The documents 101 each have associated document records 103 in the repository 108. The document records 103 contain information associated with their corresponding documents 101 such as any document decisions relating to the categorization, treatment, or other related properties of the documents 101, as described further hereinafter. Referring to FIG. 1, the documents 101 are stored in a central repository 108 that may be managed by a central group of document coordinators, such as for a corporation or law firm. The document coordinators are users of the LSA system for electronically managing the documents 101, including the remote review thereof in accordance with the present invention. It will be appreciated that the LSA users may be given varying levels of access and authority within the LSA 100. While the repository 108 is referred to as a central repository 108, it will be appreciated that an organization could have several central repositories 108 that are accessible by the LSA users. The integrity of the documents 101 in the central repository 108 is maintained by only permitting LSA users to have access to the documents 101 in the repository 108. The repository 108 stores electronic copies of the documents 101 as well as preferably stores the document records 103 containing the decisions associated with each of the documents 101. Documents record 103 electronically stored in the LSA are associated with a document 101 in the central repository 108 and may be associated with their respective documents 101 into two types of instances: the master instance, which is the master permanent or default copy of the document 101 and its associated master decisions and properties, and the production instance, which is the production copy of the document 101 and its associated production decisions and properties used for production in a particular legal matter. A production refers to a set of documents 101 that have been or will be delivered to an opposing counsel or other external party in response to a request or inquiry on a legal matter. Each document 101 has only one master instance and one set of master decisions; however, each time a document 101 is associated with a production folder in LSA, a new and unique production instance and set of production decisions is created for that document 101. A document record 103 associated with a document 101 in LSA may contain both master decisions associated with the document 101 and production decisions associated with the document 101. The master and production decisions are decisions that have made by either an LSA user or a remote reviewer and uploaded and stored in LSA 100. The decisions are preferably stored on the document record 103 in the repository 108 with the documents 101; however, it will be appreciated that the decisions could be stored in a repository or database that is separate from the documents 101 as long as they can still be searched and associated with the documents 101 in accordance with aspects of this invention. Such master or production decisions that are stored in LSA 100 are generally referred to herein as prior decisions. The decisions associated with the documents 101 may typically include document treatment, categorizations, types or properties that are made and entered by the LSA user directly or made with the assistance of a remote reviewer. These decisions include categorizations such as privileged, partially privileged, proposed for privileged, non-privileged, protected (such as proprietary or confidential to the document owner), not protected, treatments such as “produce” or “do not produce”, document types, such as purchase order or non-disclosure agreement, or issue codes such as product relation, litigation type, matter type or other predetermined decisions defined in accordance with the rules of the LSA system. It will be appreciated that the document records 103 preferably contain standardized fields associated with standard decisions related to the documents 101 for the master instance and the production instances. Such fields may be presented for selection on a user interface, such as to the LSA user or on a stand-alone decision tool 30 for a remote reviewer, as described further hereinafter. For example, the document record 103 can contain a field with a predetermined selection of privileged, partially privileged, proposed privilege or non-privileged. The document record 103 may contain another field for selection of produce, partially produce, or do not produce. Another field may have a predetermined selection of protected or not protected. Yet other fields may have predetermined selections of issue codes or document types. The standardization of these fields with predetermined selections enables the easy identification of requested remote review decisions, electronic recordation of the decisions in LSA 100, and import of the decisions into LSA 100. This enables the LSA user to electronically check for conflicts with prior decisions on the same documents 101 for a given production instance or master instance as well as to electronically identify missing or incomplete decisions by the remote reviewer. In accordance with certain aspects of the invention, the privileged and partially privileged master decisions and documents 101 associated with those decisions may not be removed or changed by an LSA user for a document 101 in the production instance, and may only be changed in the master instance by an LSA system administrator having a higher level of authority, thus avoiding inadvertent production of a privileged document 101 and possible inadvertent waiver of privilege. Even more preferably, the repository 108 contains a privileged schema for storing documents 101 having an associated privileged or partially privileged decision and a non-privileged schema for storing documents having an associated non-privileged decision. While any decisions could potentially be specified as master decisions, at least the privilege-related decisions are designated as master decisions. A detailed description of the invention regarding the privileged and non-privileged schema is found in commonly assigned patent application docket number GP-303762 entitled “System and Method for Electronically Managing Privileged and Non-Privileged Documents”, filed the same day as the present application, Jul. 2, 2004 and which is herein incorporated by reference in its entirety. Thus, the documents 101 having privileged and partially privileged decisions and their document records 103 or portions thereof are removed from and stored in an entirely separate privileged database schema such that the inadvertent production of such documents and/or inadvertent waiver of privilege is avoided. The non-privileged schema may contain a limited document record 103 associated with a matching document 101 and document record 103 in the privileged schema, that simply acts a place holder or identifier for the production instance to show that relevant privileged documents 101 have been identified, but not produced. However, the privileged documents 101 are not otherwise accessible to the LSA user in the non-privileged schema. The LSA user electronically identifies the appropriate documents 101 to comply with a request or inquiry related to a legal matter. The LSA user searches the LSA 100 for documents 101 that may be relevant or responsive to a particular inquiry, such as a discovery request or other legal pleading. In accordance with aspects of the present invention, the LSA user can identify the documents 101 that may be given consideration for a particular legal matter in LSA by foldering or holding such documents 101 in the LSA 100 and advantageously may electronically designate such held documents for remote review by a remote reviewer by name or skill set. The documents 101 for review by a remote reviewer are typically associated with a production instance, but could also be associated with a master instance. The documents 101 may be held and designated for review individually or in batches or groups. In accordance with other aspects of the invention, the documents 101 may be designated for a single or multiple joint reviews and easily exported to the remote reviewer for decisions associated with the documents that are electronically integrated back into the repository. Also advantageously, the LSA 100 allows the user to adopt documents 101 and their prior decisions, such as decisions associated with a similar prior production instance, so that additional review of the same documents 101 is not required or such that the prior review decisions can be exported and displayed for the remote reviewer for acceptance or rejection of prior review decisions. This feature is enabled since the LSA 100 beneficially stores all documents 101 and all historical prior decisions associated with the documents 101, such as in the document records 103 in the repository 108, thereby enabling efficiency of document identification by the LSA user and expedited review of documents 101 relating to similar types of legal matters or production instances. A detailed description of this inventive feature is found in commonly assigned patent application docket number GP-303763 entitled “System and Method for Electronically Managing Discovery Pleading Information”, filed the same day as the present application Jul. 2, 2004 and which is herein incorporated by reference in its entirety. It will be appreciated that the LSA user often does not have the luxury of having such similar inquiries or requests on the same documents 101 as to be able to adopt all of the prior decisions for a new, incoming request. Also, the LSA user often does not have all the knowledge or information necessary to make the final decision as to how to categorize or treat the documents 101 for the particular legal matter. In order to facilitate the necessary reviews, the LSA user electronically “holds” or designates in LSA 100 all or a portion of the documents 101 relating to a legal matter as requiring distribution to a remote reviewer for decisions on the documents 101. It is noted that LSA 100 preferably automatically blocks the ability of the LSA user to designate privileged documents for remote review, such as by allowing the user to only operate in the non-privileged schema, as described above. Accordingly, it will be appreciated that legal matters often require the review of documents 101 by one or more external or remote reviewers, such as engineers, medical personnel, other technical experts, attorneys, business persons, and possibly many others. As used herein, the term remote reviewer refers to any reviewer of documents 101 that is not an LSA user having sufficient access to the LSA 100 and the documents 101 in the repository 108 to perform their requested review on LSA 100. For any given legal matter, it will be appreciated that the documents 101 may need to be reviewed by one or more remote reviewers either simultaneously or in sequence. In accordance with aspects of the invention, numerous remote reviewers can simultaneously or sequentially review and record decisions for electronic integration into the central repository 108 by the LSA user with conflicts and discrepancies being electronically identified and resolved, as will now be described. As shown generally in FIG. 2, the LSA 100 contains a remote review tool 10 being a suite of related modules or tools 20, 30, 40, 50, 60. The remote review tool 10 advantageously provides an electronic tool for electronically managing the remote review of documents 108 for legal purposes. The remote review tool 10 permits stand-alone electronic remote review of documents 101 from the repository 108 while providing electronic integration of the review decisions into the repository 108 without the remote reviewer having access to the repository 108. The remote review tool 10 permits the LSA user to readily export the designated, electronically stored documents 101 for review by one or more remote reviewers lacking access to the repository 108. The remote review tool 10 further permits electronic integration of the review decisions back into the repository 108 by the LSA user. It will also be appreciated that the remote review tool 10, through the decision tool 30, provides a simple, user-friendly, stand-alone tool so that remote reviewers can review documents and record decisions for electronic integration into the repository 108 without having training in or access to LSA 100. In accordance with one aspect of the invention, the remote review tool 10 is preferably limited to the non-privileged schema by most LSA users so that inadvertent production of privileged documents and/or inadvertent waiver of privilege is avoided. However, it will be appreciated that a parallel remote review tool 10 could also be permitted in the privileged schema with limited access and use by a select group of LSA users in connection with a set of qualified remote reviewers, such as other attorneys working on the legal matter not having access to LSA or not being familiar with LSA. Referring to FIG. 2, the remote review tool 10 includes an export tool 20 for exporting electronic copies of documents 101 and for creating and downloading other information and data for use by the remote reviewer to conduct the remote review on a separate, stand-alone system. Other information loaded into the decision tool 30 from the export tool 20 may include data and stand-alone software regarding the types of decisions requested of the reviewer, a pick-list selection of requested decisions, prior historical decisions on the documents 101 made by the reviewer or for similar legal matters, and a tool for recording and creating a review decision file 36 for transmission back to the LSA user to associate the decisions with the documents 101 held in the central repository 108. In accordance with further aspects of the invention, the export tool 20 enables the LSA user to export documents that have been electronically marked or held as requiring distribution to a remote reviewer for decisions on the documents 101, such as by electronically foldering or otherwise marking the documents 101 for review by a particular reviewer or reviewer type. The identifications are preferably associated with a production instance of the documents 101 designated for review, but could also potentially be made in the master instance, especially for a new set of documents 101 being first input to the LSA 100. In addition, the export tool 20 also enables the LSA user to electronically export the decisions requested by the reviewer, such as by providing an electronic selection list based off computer instructions that associates requested review decisions with the documents 101 for review. Some possible selectable decisions associated with a document 101 and document record 103 were described above. In addition, the export tool 20 preferably enables the LSA user to export information to the remote reviewer regarding prior decisions associated with the documents 101, especially those that were previously made by the remote reviewer or in production for a similar legal matter. Advantageously, this LSA system 100 and remote review tool 10 optionally enable information about historical prior decisions to remain with the documents 101 for expedited and consistent review and production of documents 101 by LSA users and remote reviewers. In accordance with other aspects of the invention, the export tool 20 includes computer programs and software that enables the LSA user to electronically copy or download a copy of the designated documents 101 from the central repository 108, as well as optionally prior decisions and requested decisions 34, including any instructions related to the decisions requested and/or a pick-list of the decisions requested for each of the documents 101. The information and data generated by the export tool 20 for transmission to the remote reviewer may be loaded onto a compact disk, floppy, USB or any other portable storage device 110, as shown in FIG. 1. While the portable storage device 110 is preferred such that the remote reviewer can upload into their own remote user system 112, as described in more detail below with respect to the decision tool 30, it will be appreciated that alternately, the export tool 20 could permit downloading into a computer file that may even be external or even internal to LSA 100, but external to the repository 108 and the documents 100 and document records 103, such that the remote reviewer could then upload the exported information and use the decision tool 30 from such a computer file in their own environment without having any knowledge of LSA 100. The list of requested decisions 34 in the decisions tool 30 may be in the form of a computer file or set of computer instructions and include an electronic selection or a limited pick list of decisions requested that are associated with each of the documents. For example, the LSA user may define selections such as “produce” or “not produce”, but may not give the reviewer the opportunity to select or make decisions regarding privilege. It will be appreciated that many combinations are possible. Alternatively, there could also be free-form input fields enabling the remote reviewer to type in any comments or the remote reviewer could be allowed to flag certain documents 101 as not being amenable to the requested decision pick-list. Preferably, the export tool 20 allows the documents 101 to be copied for viewing only by the remote reviewer, although it will be appreciated that editable or markable documents 101 could also be transmitted. Referring to FIG. 1, the decision tool 30 preferably resides on a portable storage device 110 when exported such that it is easily transmittable to a remote reviewer for uploading and use with a stand-alone computer or other remote user system 112. However as noted above, it could also reside on a computer file that is transmitted or e-mailed to the remote reviewer. The decision tool 30 includes the electronic copies 32 of the documents 101 exported from LSA using the export tool 20 for remote review. As noted above, while the documents 101 are preferably digital images of the entire documents 101, they may also be native files or partial information about the documents 101 being whatever is electronically stored as the document 101 in the repository 108. The decision tool 30 also includes a set of requested decisions 34, comprising a set of computer instructions that are uploadable or readable on the computer hardware of the remote reviewer and containing instructions on making the decisions related to the documents 101. The requested decisions 34 may preferably include a limited electronic pick-list of decisions to be made for each document 101 for selection by the remote reviewer that correspond to matching fields in the document records 103 so that the decisions can easily be integrated back into LSA 100. The decision tool 30 enables the remote reviewer to create a review decisions file 36 that contains the decisions made by the remote reviewer with regard to each of the documents 101 in electronic form. The review decisions file 36 is a computer file and/or instructions with the review decisions that were made with respect to each of the documents 101, a grouping of documents 101 or a portion of documents 101 in a manner associated with those documents 101 so that the decisions can be easily uploaded into LSA 100 using an import tool 40, as described below. Preferably, the review decisions file 36 contains fields that exactly match with corresponding fields in the document records 103 so that the decisions can be electronically integrated into the repository 108. The review decisions file 36 is transmitted to the LSA user from the reviewer, and is preferably a stand-alone computer file that only contains the review decisions 36 and does not also include other parts of the decision tool 30, such as the copies of the documents 101, the decision tool software or the requested decisions file 34. The review decisions file 36 contains any type of decisions that were made with respect to the requested review documents, such as treatments, categorizations, properties and issues associated with the documents, which were described above in more detail. For example, the review decisions may include the recommended privileged status, protection status, issues codes, and production status. While the decision tool 30 may be set up to force the reviewer to make the all of the requested decisions related to all of the documents 101 prior to creating and sending the review decisions file 36 back to the LSA user, it is most typical that the reviewer will be permitted to make and save preliminary or partial decisions that can be transmitted back to the LSA user for integration. Advantageously, it will be appreciated that the decision tool 30 received by the reviewer on the portable storage device 110 is preferably customized and self-contained for the requested review, including all of the decision making software, the electronic copies of the documents, the list of requested decisions and associated pick lists, and the computer files for recording, storing and transmitting the decisions back to the LSA user. It will further be appreciated that the portable storage device 110 is preferably erased or destroyed after completion of the tasks requested of the remote reviewer. Generally for operation of the decision tool 30, the remote reviewer receives the decision tool 30 on a portable storage device 110 or in a computer file and uploads it into or reads it on a stand-alone computer remote or separate from the repository 108. The remote reviewer views the documents 101 electronically copied into the decision tool 30 and electronically reviews the requested decisions and enters the review decisions into the review decisions file 36. The remote reviewer may use the decision tool 30 in two modes—either in a view mode in which the electronic copies of the documents 101 can only be electronically reviewed without recording decisions or in a decision mode in which the remote reviewer can electronically make and save the review decisions, such as into the review decisions file 36. While the electronic copies 32, requested decisions 34, and the review decisions 36 are described as three computer files, it will be appreciated that they could reside in a single computer file or that each could reside in multiple computer files within the decision tool 30. Advantageously, the decision tool 30 is a stand-alone tool that can be used remotely from LSA 100 and permit electronic review of documents 101 by a reviewer not having access to LSA 100 while still permitting electronic integration of the review decisions into LSA 100 using the import tool 40, described next below. In accordance with yet other aspects of the invention, the import tool 40 enables an LSA user to electronically import the review decisions from a remote reviewer into the LSA and electronically associates the review decisions with their respective documents 101 in the repository 108. The LSA user receives the review decisions file 36 from the remote reviewer, such as through any suitable portable electronic storage device 110 or by e-mail or other electronic transmission. Using the import tool 30, the review decisions file 36 is electronically uploaded into LSA 100 and electronically associates the reviewer decisions contained therein with their respective documents 101. The decisions are imported into the repository 108 for association with the documents 101 for use and designation on one particular legal matter—like to produce or not produce based on scope—and the decisions are also preferably simultaneously imported into the repository 108 for association with the master or other properties of the document 101— like a proposal to mark as privileged or to mark the document 101 as being associated with a certain legal matter type or issue code. Advantageously, the import tool 40 identifies any discrepancies between the requested decisions and the received decisions, such as missing or incomplete decisions. In addition, the import tool 40 advantageously identifies any conflicts between the review decisions being currently imported and all prior decisions made on the documents 101 and stored in the repository 108 which are either matter specific in the production instance and/or which are related to any established master decisions on the documents 101. The LSA user may use the import tool 40 in different modes that may be dependent on their level of authority within LSA 100. For example, when importing decisions, the reviewer decisions that conflict with prior decisions in the repository 108 and would change the existing properties of the document 101 are preferably not automatically made to the repository 108 during the import procedure. The LSA user may upload the results decision file 36 in a passive mode such that the discrepancies and conflicts are saved into LSA 100 for reporting and resolution thereon at a later time by the same or a different LSA user. Alternately, LSA user may upload the results decision file 36 in an active mode wherein the discrepancies and conflicts are immediately identified and presented to the LSA use, such as by an interface screen, for either forced or optional resolution. For identification and resolution of discrepancies and conflicts, the remote review tool 10 further includes a report tool 50 and a resolution tool 60 that performs those functions within LSA 100, as will now be described. The report tool 50 and the resolution tool 60 are considered part of the import tool 40 for purposes of this description, even though they may be integral with or separate from the portion of the import tool 40 that imports the remote review decisions to the repository 108 and may be used simultaneously therewith or independent therefrom. For example, the review decisions file 36 may contain a decision that a document 101 not be protected for a particular legal matter when the document 101 has a master status of protected. When importing the decision, the LSA user would need to decide whether this is an acceptable altered decision for that document and could 1) accept the decision into the central repository 108 to be associated with that document 101 as to be produced for the particular matter or 2) reject the decision (with or without requiring a reason to be inserted into the central repository 108 as to a reason for the rejection) or 3) could hold off and/or store the decision to be considered by either another LSA user or another remote reviewer before final acceptance and integration into the document record 103. It will further be appreciated that final authoritative decisions on the documents 101 may be made by a non-LSA user, such as an outside counsel or an in-house counsel that is not an LSA user. Advantageously, these final decisions can be recorded remotely using the decision tool 30 and electronically imported and accepted by the LSA user into the system so that final, historical and complete decisions are stored in LSA 100. In accordance with yet other aspects of the invention, the import tool 40 includes the report tool 50 that enables the LSA user to identify discrepancies between the requested review decisions and the resultant review decisions received, such as missing or incomplete decisions. In addition, the report tool 50 enables the LSA user to identify conflicts between the review decisions being currently imported for the documents 101 and any prior decisions in the repository 108. Using the report tool 50, the responsible LSA user can request an electronic identification of all imported decisions having discrepancies or conflicts for particular designated matters, folders, or more generally associated with documents 101 having a certain set of properties. The report tool 50 can provide reports to the LSA user identifying the discrepancies and conflicts related to requested documents 101. The report tool 50 can provide electronic and/or paper reports automatically upon uploading the results review decision file 36 into LSA such as by immediate presentation of the report on a screen interface to the LSA user during import or by sending the report to the LSA user by e-mail or other notification. Alternately, the report tool 50 can be used upon demand by the LSA user to generate reports. It will further be appreciated that upon export of the decision tool 30 to a remote reviewer, that certain basic information such as the reviewer, the date sent, the date due and other such information are stored in the LSA 100. Thus, the report tool 50 can also advantageously be used by the LSA user to easily track the status of outstanding review requests. The resolution tool 60 enables the LSA user to resolve conflicts between prior decisions stored in the repository 108 and imported decisions received from the remote reviewer. The resolution tool 60 may also enable the LSA user to resolve discrepancies between the requested decisions and the received review decisions. The resolution tool 60 may automatically be presented during the importation of the review results decision file 36 into LSA or may be used upon demand by the LSA user to resolve saved discrepancies and conflicts stored in LSA during the importation of the results review decisions file 36. The resolution tool 60 electronically presents the discrepancies and conflicts for the documents 101 to the LSA user, such as by an interface screen, whereby the LSA user can electronically make decisions and resolve the outstanding issues in LSA 100 to complete the integration of the review decisions into the repository 108 by accepting, rejecting, or holding the issue. For example, the resolution tool 60 presents the issue of the review decision being to “protect” the document while the master status or prior decision for the document is “not protected”. The LSA user could reject the reviewer's decision and close that issue. As another example, the resolution tool 60 presents the issue of the review decision being to “produce” while the prior decision for a particular production is “not produce”. The LSA user could accept the new review decision and close the issue such that the decision becomes integrated into the central repository 108 and remains historically associated with the document 101. As yet another example, the resolution tool 60 presents the review decision as being “proposed privilege” while the prior decision associated with the document 101 is “not privileged” or silent on that issue. In this case, the document 101 would be placed on hold for further consideration of a final decision regarding privilege by either the same or a different LSA user. For other conflicts and discrepancies that the importing LSA user cannot resolve, the LSA user could hold or postpone the resolution for another LSA user or remote reviewer having authority to make the decision—such as by setting up an internal review file in LSA for another user or by foldering or holding the documents 101 for another remote review. The LSA user could also send a copy of the discrepancies report (missing or incomplete decisions) generated using the report tool 50 out to the remote reviewer to complete using the reviewer's decision tool 30 already earlier received by the reviewer or by creating a new decision tool 30 that requests decisions only on the discrepancies. It will be appreciated that the remote review tool 10 enables an LSA user to electronically manage the remote review of documents 101 for legal purposes. The LSA user can electronically identify, restrict, transmit, and track the documents sent to a remote reviewer and designate the requested decisions. It also enables the LSA user to readily electronically integrate the review decisions back into a centralized repository 108 of the documents 101. Furthermore, the LSA user can exactly match the decisions back to the correct documents 101 and document records 103 using their electronic document identification so that decisions are not accidentally associated with an incorrect document or document version. The remote review tool 10 enables the LSA user to readily identify and reconcile any conflicting review decisions against prior decisions made on the documents either in the master instance or the production instances. The LSA user is also able to electronically identify any missing or otherwise deficient or incomplete decisions by the remote reviewers. This is all accomplished while maintaining the integrity of the electronically stored documents 108 in the centralized repository 108 as well as easily recording and storing the historical review decisions associated with the documents 101. It will be appreciated that although certain features and functions of the overall remote review tool 10 are shown as residing in certain specific tools 20, 30, 40, 50, 60, the tools 20, 30, 40, 50, 60 can reside in separate computer files and instructions on separate computer hardware or can reside in a single computer file on a single set of hardware. For example, it will be appreciated that the decision tool 30 could reside within LSA 100, but that the remote reviewer would be a person having access to LSA, but not with access to the document repository 108 as would be required to review the documents 101 and enter decisions related thereto. It will further be appreciated that the import, export, reporting and resolution tools 20, 40, 50, 60 could all reside in a single computer file or set of instructions within LSA 100. It will be appreciated that a single LSA user may have access to all of the tools 20, 30, 40, 50, 60 comprising the remote review tool 10 or that various users may only have access to various pieces of the remote review tool 10. For example, an LSA user could be responsible for identifying the documents 101 within LSA 100 requiring remote review, but that another LSA user would actually use the import, export, reporting and resolution tools 20, 40, 50, 60. It will further be appreciated that some LSA users could use the export tool 20 while other LSA users can use the import tool 30. It will also be appreciated that the report and/or resolution tools 50, 60 could be restricted to certain LSA users having a higher level of access than those using the export and import tools 20, 40. Many combinations of LSA user access are possible. In FIG. 1, a block diagram of an exemplary system for electronically managing document review using the remote review tool 10 is generally shown. The LSA system, generally indicated as 100, includes one or more LSA user systems 102 through which LSA users at one or more geographic locations may contact the host system 104. The host system 104 executes computer/software instructions for the remote review of documents 101 for legal purposes, as previously described. For example, the export tool 20, the import tool 40, the report tool 50, and the resolution tool 60 reside on the host system 104, while the decision tool 30 resides remotely. The user systems 102 are coupled to the host system 104 via a network 106. Each user system 102 may be implemented using a general-purpose computer executing a computer program for carrying out the processes described herein. The user systems 102 may be personal computers (e.g., a lap top, and a personal digital assistant) or host attached terminals. If the user systems 102 are personal computers, the processing described herein may be shared by a user system 102 and the host system 104 (e.g., by providing an applet to the user system 102). The network 106 may be any type of known network including, but not limited to, a wide area network (WAN), a local area network (LAN), a global network (e.g., Internet), a virtual private network (VPN), and an intranet. The network 106 may be implemented using a wireless network or any kind of physical network implementation known in the art. A user system 102 may be coupled to the host system 104 through multiple networks (e.g., intranet and Internet) so that not all user systems 102 are coupled to the host system 104 through the same network. One or more of the user systems 102 and the host system 104 may be connected to the network 106 in a wireless fashion. In one embodiment, the network is an intranet and one or more user systems 102 execute a user interface application (e.g., a web browser) to contact the host system 104 through the network 106, while another user system 102 is directly connected to the host system 104. In another exemplary embodiment, the user system 102 is connected directly (i.e., not through the network 106) to the host system 104 and the host system 104 is connected directly to or contains the central repository 108. The central data repository 108 may be implemented using a variety of devices for storing electronic information. It is understood that the repository 108 may be implemented using memory contained in the host system 104 or user system 102, or that the repository 108 may be implemented by a separate physical device. The repository 108 includes the documents 101 and is logically addressable as a consolidated data source across a distributed environment that includes a network 106. Information electronically stored in the repository 108, such as the documents 101 and document records 103, may be retrieved and manipulated via the host system 104 or the user system 102. In an exemplary embodiment of the present invention, the host system 104 operates as a database server and coordinates access to application data including data stored in the repository 108. The repository 108 preferably contains the privileged schema and a non-privileged schema. Databases within these schemas contain documents 101 wherein some or all of the documents 101 are grouped into folders. In addition, it will be appreciated that there may be separate databases for different practice areas (e.g., labor, environmental, and intellectual property) and/or separate databases for different types of legal matters. The documents 101 in the databases are typically scanned documents that are stored as images. Having a privileged schema and a non-privileged schema allows privileged content to be stored separately from non-privileged content, as previously described. Each schema contains its own database entities (e.g., fields, tables, views, and triggers), entity relationships, data, access and security restrictions. Access to the privileged and non-privileged schemas is based on the security levels associated with individual LSA users. The repository 108 also includes production folder tables and other kinds of data such as compact disk (CD) export date and user-id. In an exemplary embodiment, the host system 104 operates as a database server and coordinates access to application data including data stored on the repository 108. The host system 104 depicted in FIG. 1 may be implemented using one or more servers operating in response to a computer program stored in a storage medium accessible by the server. The host system 104 may operate as a network server (e.g., a web server) to communicate with the user system 102. The host system 104 handles sending and receiving information to and from the user system 102 and can perform associated tasks. The host system 104 may also include a firewall to prevent unauthorized access to the host system 104 and enforce any limitations on authorized access. For instance, an LSA administrator may have access to the entire system and have authority to modify portions of the system. A firewall may be implemented using conventional hardware and/or software, as is known in the art. The host system 104 may also operate as an application server. The host system 104 executes one or more computer programs for electronically managing the remote review of documents 101 using the remote review tools 10 supported therein. In addition, the host system 104 houses and manages other computer programs associated with LSA 100. Processing may be shared by the user system 102 and the host system 104 by providing an application (e.g., java applet) to the user system 102. Alternatively, the user system 102 can include a stand-alone software application for performing a portion or all of the processing described herein. As previously described, it is understood that separate servers may be utilized to implement the network server functions and the application server functions. Alternatively, the network server, the firewall, and the application server may be implemented by a single server executing computer programs to perform the requisite functions. FIG. 2 also includes the portable storage device 110 that contains data, information and computer instructions that have been written to the portable storage device by the export tool 20 within the remote review tool 10. The portable storage device 110 (e.g., a compact disk, a universal serial bus device, a floppy disk, etc.) contains the decision tool 30 including electronic copies of the documents 101 from the repository 108 to be reviewed by the remote reviewer, as well as the computer instructions to execute the review on a remote user system 112 used by the remote reviewer. The remote system 112 may have the same characteristics described above in reference to the user system 102 or the host system 104. In accordance with aspects of this invention invention, the remote system 112 does not have access to the host system 104 or to documents 101 in the repository 108. As part of the decision tool 30 contained on the portable storage device 110, software to view images of the documents 101 is included as well as software to create and write to the decision file 34 (e.g., Microsoft Access). A reviewer at the remote system 112 receives and executes the decision tool 30 on the portable storage device 110. The remote reviewer electronically reviews documents 101 from the portable storage device 110 and makes and records review decisions into the review decisions file 36 as requested from the requested decisions file 34. The review decisions file 36 is sent to the user system 102 or host system 104 for integration into the repository 108 using the import tool 40, as previously described above. The review decisions file 36 is created by the remote user via the decision tool 30 and transmitted to an LSA user at the user system 102 or host system 104 for integration into the databases on the repository 108 using the import tool 40 wherein the decisions 101 can be electronically associated with the reviewed documents 101, as described above. The review decisions may be electronically transmitted to the user system 102 or host system 104 (e.g., via e-mail) or alternatively by a portable storage medium, such as a floppy disk, CD, USB, etc. may be given to an input operator or LSA user for input to the host system 104. Other configurations, including those previously described herein, may be utilized to support electronically managing the remote review of documents 101 for legal purposes, and the system is not limited to the specific configuration depicted in FIG. 1. FIG. 4 is a flow diagram of a process for identifying and exporting documents 101 for remote review that may be utilized by exemplary embodiments of the present invention. In the example depicted in FIG. 4, at 302, a production folder is populated by the LSA user to include documents 101 for review by a particular remote reviewer. Alternatively, an existing production folder may be utilized. At 302, documents are associated to a production folder. Any document privilege statuses in the LSA are maintained by preventing privileged documents 101 from being added to the production folder. In addition, any documents 101 with privileged portions have the privileged portions redacted before being added to the production folder. In accordance with an embodiment of the invention, a document folder refers to a collection of documents 101 that are grouped by the LSA user into a specific folder. These documents 101 may relate to a single case or to a specific issue, etc. A production folder refers to a grouping of documents 101 produced or proposed for production and may be similarly related to one another as described above with respect to the documents 101 in a document folder. In addition, the documents 101 in a production folder may be grouped together for export and review by the same reviewer or group of reviewers. The database on the repository 108 includes a production folder table and a document table. The document table includes fields such as: a unique document identifier; a document type (e.g., memo, letter, drawing, photograph, transcript, manual, etc.); a database identifier to identify the database where the document is located; an accession range; an attachment range; case number; discovery fields; product information; privilege information; and issue information. The production folder table includes fields such as: unique production document identifier; production folder identifier; production identifier; and production privilege category. Referring to FIG. 4, at 304, a status of “hold without review” is assigned to the production folder that was created in 302. A user at user system 102 initiates the assignment. In the present embodiment, there are four production decisions that may be assigned to a production folder: individual review (no decision); hold without review; do not produce without review; and produce without review. By designating individual review, the decision of whether to produce or not is postponed. When a user designates “hold without review”, a decision to hold the documents 101 is assigned with a description of the hold reason and the person for whom the documents 101 are held. The “produce without review” option assigns a decision to produce all of the documents 101 in the production folder. “Do not produce without review” causes a decision to be assigned that results in all of the documents 101 within the folder being held without production. Subsequent users of the production folder are told of the hold without review status. However subsequent LSA users with the proper authority are not prevented from changing the status. At 306, the hold for role (e.g., electrical engineer, mechanical engineer, outside attorney), hold for name and hold reason(s) are entered for the production folder by the user at the user system 102. Hold reason(s) may include items such as further review required, illegible, missing pages, etc. Hold for name is the name of the remote reviewer and hold for role refers to the skills that a reviewer should possess. At 308, a request is made by the user, via the user system 102, to use the export tool 20 to create a portable storage device 110 with the copies of the documents 101 (e.g., heading information and images) and the decision tool 30 associated with the production folder. At 310, the documents 101 in the production folder are loaded onto the portable storage device 110. In an exemplary embodiment of the present invention, the documents 101 on the portable storage device 110 are read only and protected from being copied. As described previously, the portable storage device 110 may be any portable storage medium having capacity to hold the decision tool 30 including the production folder documents 101 and the computer instructions and software for executing the remote review. In addition, the decision tool 30 may be transmitted via a network. Also, 302 through 308 may be performed more than once to create a portable storage device 110 with more than one production folder for review. FIG. 3 is a flow diagram of a process for remote review of documents 101 that may be utilized by exemplary embodiments of the present invention. At 202, the documents 101 for remote review are identified in the LSA 100 and exported using the export tool 10 onto a portable storage device 110. At 204, a remote reviewer (e.g., an outside expert) on the remote user system 112 reviews the documents 101 on the portable storage device 110 and enters recommended decisions in a decision file 36 for one or more of the documents 101 in the production file. This processing is performed at the remote system 112 using the decision tool 30 provided on the portable storage device 110. FIG. 5 is a flow diagram of an exemplary process for remote reviewing of documents for legal purposes using the decision tool 30. At 402, the remote reviewer at the remote system 112 is prompted to select a document 101 from one of the production folders located on the portable storage device 110. At 404, the reviewer views the selected document. Any image viewer that allows the reviewer to view the document may be utilized by the decision tool 30 or alternatively, the decision tool 30 may include specialized software tailored to a particular implementation. At 406, the remote reviewer enters a review decision for the current document 101 being viewed. The decision tool 30 stores the decision for the document 101 into a review decision file 36. As one example, the remote reviewer may recommend that the document 101 be produced or not produced. If the reviewer recommends that the document 101 not be produced, then the reviewer will be prompted (e.g., via a list box of valid reasons) by the decision tool 30 to provide reasons for not producing the document 101, such as from an electronic pick-list. Examples of reasons for not producing a document 101 include attorney client privileged, attorney client work product, not responsive, outside of scope, outside of complaint allegation. Other feedback about the document 101 may be generated by the reviewer on the remote system 112 and stored in the decision file 36. For example, the reviewer may propose whether the document 101 should be privileged or non-privileged. In addition, the reviewer may propose issue codes to be associated with the document 101. The issue codes could be selected from a list box of valid issue codes. Exemplary embodiments of the present invention may be utilized to provide any type of document categorization for entry into the LSA databases depending on implementation requirements. Different categorizations may be available to different reviewers depending on the authorizations given to them by the creator of the portable storage device 110 and/or on user profiles stored in the host system 104. At 408 in FIG. 5, the reviewer is prompted by the decision tool 30 to select another document 101 for review or to transmit the decision file 36 to the LSA 100. If the reviewer indicates that another document 101 should be reviewed, then the processing starting at 402 is initiated. If the reviewer indicates that the review is completed, then 410 is performed to transmit the decision file 36 (e.g., via a network, via an e-mail message, via a floppy disk, etc . . . ) to the LSA 100 system. In an alternate embodiment, the reviewer may also indicate that the review is not complete but that the reviewer would like to exit and return at a later time to continue the review of the documents 101. Returning to FIG. 3, at 206 the review decisions file 36 is imported into the LSA on the host system 104, such as by using the import tool 40. The recommendations contained in the review decisions file 36 are then correlated to the documents 101 in the LSA 100. The recommendations are added to document records 103 in the database tables that correspond to the documents 101 either in their production or master instances. At 208, reports are generated to report any discrepancies and conflicts. These reports may be automatically generated to alert LSA users of the status or be generated upon demand by the LSA user. Additional reports such as a report listing all of the decisions made by a particular remote reviewer or on a particular date via the remote review tool 10 may also be generated. As described above, the embodiments of the invention may be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. Embodiments of the invention may also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits. While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The present invention relates generally to a system and method for electronically managing remote review of documents for legal purposes. More specifically, the invention relates to an improved system and method for permitting stand-alone remote review of the documents while providing integration with a repository where the documents are electronically stored. Legal matters often involve massive volumes of information that must be organized and categorized in response to particular inquiries or issues, such as litigation pleadings, business transactions, government regulations, etc. The information is typically managed by a centralized organization, such as a legal department or group therein having document coordinators. Managing this documentary information often requires the review and input of persons remote or external to the centralized organization, such as other attorneys, business persons, or experts. The remote reviewers are typically requested to provide their opinion or decision on the categorization and treatment of the information for a particular legal matter, for example, such as to produce or not produce in response to a discovery request. At times there may be numerous remote reviewers reviewing numerous sets or subsets of documents whose decisions must be recorded. Also, conflicting decisions must be identified and reconciled with each other. It must also be ensured that the decisions of the remote reviewers are correctly matched back to the exact same document or version of the document for which their input is being sought. Existing methods for remote document review are time-consuming and not easily managed, tracked, recorded and reconciled. For example, the central document coordinator identifies a set of documents from the central repository needing external review. The external reviewers are typically located remote from the central document repository and are barred from accessing the repository in order to protect integrity of the documents stored in the repository. Thus, the coordinator prepares paper copies of the documents for review and sends them out to each of the remote reviewers for their stand-alone, external review. The coordinator manually ensures that the information sent for review is appropriately restricted, such as by removing privileged documents or portions thereof. The coordinator also has to somehow indicate the decisions that are requested for each of the documents, by manually creating a letter or other type of notice to the reviewer for the documents. The coordinator has no convenient way to track the status of the outstanding remote review requests. Under existing review methods, the remote reviewers return the paper documents together with a particular decision—such as produce, do not produce, mark as privileged, defer to another reviewer, etc . . . The returned documents are not necessarily in any particular order. As to each document, the coordinator must identify and resolve any conflicting decisions of different remote reviewers and any conflicts with prior decisions stored in the repository. This is typically done document by document—such as by manually sorting the documents or using a crude spreadsheet listing the documents and all of the current and prior decisions. The coordinator must also manually transfer any redactions and decisions onto the centralized document copy for the particular legal matter. Typically there is no historical record of decisions by the remote reviewer except in the paper file of that particular legal matter or as marked on the reviewer's document copy. Thus, the same or related reviewer may review the same documents for the same or a similar inquiry over and over again—sometimes even inadvertently being inconsistent with their prior decisions. Furthermore, other than the coordinator handling the specific legal matter, no other coordinator has ready access to decisions that have been made on a particular document by a remote reviewer except by finding and reviewing the paper documents for the other related legal matter. This can be especially problematic for documents that have been previously categorized as privileged. In some instances, due to the time-consuming tracking effort involved, the final decision of the last remote reviewer may not necessarily be logged back into the central repository and recorded with the particular document and legal matter. Thus, it is desirable to be able to easily identify, restrict, transmit, and track the documents sent to a remote reviewer, and to readily integrate the review decisions back into a centralized document repository. Further, it is desirable to easily match the decisions back to the correct document in the repository as well as to identify and reconcile any conflicting review decisions against prior decisions made as to the documents. It is also desirable to be able to easily identify any missing or otherwise deficient or incomplete decisions by the reviewers. Additionally, it is desirable to maintain the integrity of the documents stored in the centralized repository as well as easily record and store the historical review decisions in respect to the documents.
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<SOH> BRIEF DESCRIPTION OF THE INVENTION <EOH>According to one aspect of the invention, a system and method are provided for electronically managing the remote review of documents that are stored in a central repository. The inventive system and method advantageously enable a remote reviewer, lacking repository access, to remotely review and record decisions in respect to documents stored in the repository and then electronically integrating those remotely made decisions back into the repository. In another aspect of the inventive system and method for electronically managing the remote review of documents stored in a central repository, an export tool is provided for exporting a copy of one or more documents for remote review by a reviewer lacking access to the repository, and an import tool is provided for importing decisions of the remote reviewer back into the central repository in association with the documents reviewed. In a further aspect of the invention, a stand-alone decision tool enables a remote reviewer to electronically review documents from a central repository and record decisions about the documents for integration into the repository without having access to the repository. The electronic decision tool contains electronic copies of the documents for review thereby enabling the reviewer to electronically review the documents with the decision tool without having access to the documents in the repository. The electronic decision tool also contains a list of decisions requested of the reviewer for each of the documents and a selection tool for electronically recording the requested decisions thereby enabling the reviewer to electronically record the requested decisions into the decision tool for transmission back to the repository. In yet another aspect of the invention, the system includes an import tool that identifies discrepancies between decisions requested of the reviewer and decisions made by the reviewer as well as conflicts with prior decisions stored in the repository thereby enabling resolution of the discrepancies and conflicts as well as insuring consistency in handling of the documents.
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20040702
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20100413
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20050106
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95367.0
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MYINT, DENNIS Y
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SYSTEM AND METHOD FOR ELECTRONICALLY MANAGING REMOTE REVIEW OF DOCUMENTS
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UNDISCOUNTED
| 0
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ACCEPTED
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10,884,134
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ACCEPTED
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Motor assembly of X2Y RFI attenuation capacitors for motor radio frequency interference (RFI) and electromagnetic compatibility (EMC) suppression
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A connector structure for a brush motor includes a connector body 10 associated with the motor, an X2Y capacitor structure 20, a positive power terminal connection structure 14 associated, a negative power terminal connection structure 14′ and a ground connection structure 16. The positive power terminal connection structure is electrically connected with the capacitor structure and is constructed and arranged to electrically engage a positive power terminal 18 of the motor. The negative power terminal connection structure 14′ is electrically connected with the capacitor structure and is constructed and arranged to electrically engage a negative power terminal of the motor. The ground connection structure 16 is electrically connected with the capacitor structure and is constructed and arranged to be electrically connected with a ground mass. The X2Y capacitor structure provides RFI suppression.
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1. A connector structure for a brush motor, comprising: a connector body associated with the motor, an X2Y capacitor structure, a positive power terminal connection structure associated with the connector body, the positive power terminal connection structure being electrically connected with the capacitor structure and being constructed and arranged to electrically engage a positive power terminal of the motor, a negative power terminal connection structure associated with the connector body, the negative power terminal connection structure being electrically connected with the capacitor structure and being constructed and arranged to electrically engage a negative power terminal of the motor, and a ground connection structure being electrically connected with the capacitor structure and being constructed and arranged to be electrically connected with a ground mass. 2. The connector structure of claim 1, wherein the ground connection structure electrically connects to the capacitor structure at two different locations. 3. The connector structure of claim 1, wherein the ground connection structure is a stamping of electrically conductive material of generally U-shaped configuration defining two opposing sides joined by a central portion, the two opposing sides engaging a portion of the connector body. 4. The connector structure of claim 3, wherein each side includes a plurality of spring tabs constructed and arranged to engage the ground mass. 5. The connector structure of claim 3, wherein the central portion includes an opening constructed and arranged to receive the positive power terminal connection structure, the negative power terminal connection structure, and the capacitor structure. 6. The connector structure of claim 5, wherein the central portion includes opposing spring contacts that extend into the opening and resiliently contact ground areas of the capacitor structure. 7. The connector structure of claim 1, wherein the positive and negative power terminal connection structures are stampings of electrically conductive material disposed to define a space there-between, the capacitor structure being mounted in said space. 8. The connector structure of claim 7, wherein each of the positive power terminal connection structure and negative power terminal connection structure includes a main body having first spring structure constructed and arranged to resiliently engage an associated power terminal of the motor, and second spring structure constructed and arranged to resiliently engage the capacitor structure in the space. 9. The connector structure of claim 8, wherein the ground connection structure includes an opening constructed and arranged to receive the positive power terminal connection structure, the negative power terminal connection structure, and the capacitor structure, and wherein the ground connection structure includes opposing spring contacts that extend into the opening. 10. The connector structure of claim 9, wherein the capacitor structure is generally rectangular and the second spring structure of the positive power terminal connection structure engages one side of the capacitor structure, the second spring structure of the negative power terminal connection structure engages a side of the capacitor structure opposite the one side, and the spring contacts of the ground connection structure engage remaining sides of the capacitor structure. 11. The connector structure of claim 1, wherein the positive and negative power terminal connection structures are configured substantially identically. 12. An assembly for a motor, the assembly comprising: an X2Y capacitor structure, a positive power terminal connection structure being electrically connected with the capacitor structure and being constructed and arranged to electrically engage a positive power terminal of the motor, a negative power terminal connection structure being electrically connected with the capacitor structure and being constructed and arranged to electrically engage a negative power terminal of the motor, and a ground connection structure being electrically connected with the capacitor structure and being constructed and arranged to be electrically connected with a ground mass. 13. The assembly of claim 12, wherein the ground connection structure electrically connects to the capacitor structure at two different locations. 14. The assembly of claim 12, wherein the ground connection structure is a stamping of electrically conductive material of generally U-shaped configuration defining two opposing sides joined by a central portion, the two opposing sides being constructed and arranged to engage a connector body of the motor. 15. The assembly of claim 14, wherein each side includes a plurality of spring tabs constructed and arranged to engage the ground mass. 16. The assembly of claim 14, wherein the central portion includes an opening constructed and arranged to receive the positive power terminal connection structure, the negative power terminal connection structure, and the capacitor structure. 17. The assembly of claim 16, wherein the central portion includes opposing spring contacts that extend into the opening and resiliently contact ground areas of the capacitor structure. 18. The assembly of claim 12, wherein the positive and negative power terminal connection structures are stampings of electrically conductive material disposed to define a space there-between, the capacitor structure being mounted in said space. 19. The assembly of claim 18, wherein each of the positive power terminal connection structure and negative power terminal connection structure includes a main body having first spring structure constructed and arranged to resiliently engage an associated power terminal of the motor, and second spring structure constructed and arranged to resiliently engage the capacitor structure in the space. 20. The assembly of claim 19, wherein the ground connection structure includes an opening constructed and arranged to receive the positive power terminal connection structure, the negative power terminal connection structure, and the capacitor structure, and wherein the ground connection structure includes opposing spring contacts that extend into the opening. 21. The assembly of claim 20, wherein the capacitor structure is generally rectangular and the second spring structure of the positive power terminal connection structure engages one side of the capacitor structure, the second spring structure of the negative power terminal connection structure engages a side of the capacitor structure opposite the one side, and the spring contacts of the ground connection structure engage remaining sides of the capacitor structure. 22. The assembly of claim 12, wherein the positive and negative power terminal connection structures are configured substantially identically. 23. A connector structure for a brush motor, comprising: a connector body associated with the motor, an X2Y capacitor structure, first means, associated with the connector body, for electrically connecting with the capacitor structure and for electrically engaging a positive power terminal of the motor, second means, associated with the connector body, for electrically connecting with the capacitor structure and for electrically engaging a negative power terminal of the motor, and third means for electrically connecting with the capacitor structure and for electrically connecting with a ground mass.
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This application is based on U.S. Provisional Application No. 60/564,558, filed on Apr. 22, 2004, and claims the benefit thereof for priority purposes. FIELD OF THE INVENTION The invention relates to suppression of RFI for brush motors for automotive applications based on X2Y technology. BACKGROUND OF THE INVENTION Motor RFI Suppression is commonly completed by the use of a multitude wire wound inductors in series with the brushes and a film or ceramic capacitor in parallel to the power supply source. An improved RFI suppression package, based on new technology of the X2Y component, is needed. Details of the X2Y can be found at http://www.x2y.com. An X2Y component is a four terminal device with unique architecture. X2Y is based on a standard bypass capacitor as a foundation provided with additional “reference” electrodes and two side terminations, called G1(ground) and G2, which are attached to the reference electrodes. Inserting parallel reference electrodes inside the bypass capacitor by dividing an unbalanced single end device, a balanced device is created. A balanced device is composed of two nominally identical halves. The main benefits of balance are: Two tight tolerance “Y” capacitors (1-2.5%); Temperature variation effects elimination; Voltage vs. capacitor variation becomes equalized line-to-line. FIG. 1 shows a conventional X2Y component or capacitor 11 where two side terminations (G1 and G2) attached to the reference electrodes results in acquiring one package consisting of the three capacitors. Cx is a capacitor between power lines and Cy is a capacitor between one power line and ground. The X2Y configuration is similar to a dual rectangular coaxial structure. An internal Faraday cage forms a shielded container for each conductor (+Bat and −Bat) inside the capacitor. At high frequency, the circuit noise in each capacitor will choose the low impedance path of the shield and opposing noise current will be cancelled. Inside the X2Y component, every other layer within the single component body is in opposition to cancel the magnetic fields. The components circuit inside operates simultaneously in multi-modes (Common and Differential Mode Noise Coupling). X2Y components reduce Electro-magnetic Interference (EMI) by means of field cancellation. By contrast, standard components are using capacitance to shunt noise or inductors to block noise with high impedance. X2Y components are in by-pass and effectively filtering only the noise. Because they are in by-pass X2Y components do not heat up like standard components. The way the X2Y component is attached and placed can have major effects on how well it performs. Some special study and experimental research have been done to get maximum broadband filtering performance. There is a need to provide an X2Y capacitor in a motor connector for Radio Frequency Interference (RFI) suppression. SUMMARY OF THE INVENTION An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by providing a connector structure for a brush motor. The connector structure includes a connector body associated with the motor. An X2Y capacitor structure is provided. A positive power terminal connection structure is associated with the connector body and is electrically connected with the capacitor structure and is constructed and arranged to electrically engage a positive power terminal of the motor. A negative power terminal connection structure is also associated with the connector body. The negative power terminal connection structure is electrically connected with the capacitor structure and is constructed and arranged to electrically engage a negative power terminal of the motor. A ground connection structure is electrically connected with the capacitor structure and is constructed and arranged to be electrically connected with a ground mass. Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which: FIG. 1 is a schematic illustration of a conventional X2Y capacitor. FIG. 2 is a circuit diagram showing the electrical position of a X2Y capacitor relative to a motor in accordance with the invention. FIG. 3 is a perspective view of an X2Y capacitor mounting assembly shown coupled with a motor connector body in accordance with the invention. FIG. 4 is a perspective view of the X2Y capacitor mounting assembly of FIG. 3 showing the power terminals attached thereto. FIG. 5 is a perspective view of a ground connection component of the X2Y capacitor mounting assembly of FIG. 4. FIG. 6 is a perspective view of the X2Y capacitor mounting assembly of FIG. 4 shown with the power terminals attached thereto and without the ground component attached. FIG. 7 is a perspective view of a power terminal connection component of the X2Y capacitor mounting assembly of FIG. 4. DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT The present invention utilizes the X2Y technology to for motor RFI suppression. The mechanical assembly of such a balanced line electromagnetic interference (EMI) chip is not intuitive to meet the requirements of automotive environments and low cost assembly. The embodiment details a mechanical structure to package a capacitor into a motor connector body and utilizes low cost assembly techniques and components. The X2Y capacitor is small in size relative to the components of the assembly and is difficult to fit without utilizing tradition printed circuit board techniques. The X2Y capacitor is relatively new to the motor industry and the details of the incorporating the X2Y capacitor into a motor connector are described below. FIG. 2 is a circuit diagram showing the electrical position of a X2Y capacitor 20 relative to a motor 13 in accordance with the invention. With reference to FIG. 3, a motor connector body 10 is shown including an X2Y capacitor mounting assembly, generally indicated at 12, in accordance with the principles of the invention. The assembly 12 includes three conductive components manufactured by a sheet metal forming operation and a conventional X2Y capacitor 20. The three conductive components include a positive power terminal connection component 14, a negative power terminal connection component 14′ and a ground connection component 16. FIG. 7 shows a power connection component 14 that is substantially identical to component 14′. The positive and negative power terminal connection components 14, 14′ are each preferably a stamped component that surrounds the associated power terminal. Thus, component 14 surrounds the positive power terminal 18 and component 14′ surrounds the negative power terminal 30 (FIG. 6). The power terminal connection components 14, 14′ have a mechanical interference spring connection and/or solder connection to the associated terminal 18, 30 and have a mechanical or solder connection to the X2Y capacitor 20. In the illustrated embodiment, each component 14, 14′ includes a main body 22 bent to have an upstanding portion 24. The body 22 includes first spring structure 26 constructed and arranged to resiliently engage an associated terminal 18, 30. The upstanding portion 24 includes a second spring structure 28 constructed and arranged to resiliently engage the generally rectangular X2Y capacitor 20 in space 25 between the two components 14 and 14′ (FIG. 6). Components 14, 14′ are preferably made of a conductive material capable of carrying low currents such as phosphor bronze or beryllium copper or copper or brass. The components 14, 14′ are preferably mechanically fit onto the motor connector 10 and held thereon by the means of an interference clip on the component 14, 14′ or by a clip on the connector 10. Surrounding the positive and negative power terminals with component 14 and component 14′, respectively, prevents noise from bypassing the X2Y capacitor 20 and suppresses noise in the nearest proximity to the noise source (motor's brushes). With reference to FIG. 3-5, the ground connection component 16 is preferably a stamped component that surrounds, without contacting, both the positive and negative power connection components, 14, 14′. Component 16 has a mechanical interference spring connection and/or solder connection to the X2Y capacitor 20. In the illustrated embodiment, the component 16 includes a main body that is stamped into a generally U-shaped configuration defining two opposing sides 32, 34 joined by a central portion 35. Each side 32, 34 includes spring structure 36 in the form of a plurality of spring tabs 37. The component 16 is constructed and arranged so that it can be placed over a portion of the motor connector 10 with the spring structure 36 engaging a portion of the connector 10. The small spring tabs 37 provide an overall low inductance multiple ground connection to the ground mass and reduces parasitic inductance of that connection. The ground connection can be made to the end cap, stator or motor mounting flange. The multiple parallel connections to ground reduce the total inductance between the X2Y capacitor 20 and ground. In the embodiment, the central portion 35 of the component 16 includes an opening 40 for receiving the component 14, 14′ and the X2Y capacitor 20. To provide ground contact with the X2Y capacitor, the central portion 35 includes opposing spring contacts 44 that extend into the opening and resiliently contact ground areas 46 (FIG. 6) of the X2Y capacitor 20. Of course, instead of or in combination with the spring contacts 44, a solder connection can be made in two places with the X2Y capacitor 20. Component 16 is preferably made of a conductive material capable of carrying low currents such as phosphor bronze or beryllium copper or copper or brass. The component 16 is mechanically fit onto the motor connector 10 and is held on by the means of an interference clip on the component 16 or clip on the connector 10. A function of the component 16 is to bypass High Frequency such as, for example, 70 MHz-108 MHz noise. Therefore, the area of the ground connection has to be large to minimize total impedance of component 16. The X2Y capacitor 20 connects to the component 16 at two points via contacts 44 in order to decrease internal X2Y inductance. All connections should be as short and wide as possible to reduce impedance. Components 14, 14′ and component 16 form a mechanical socket that permits ease of assembly of the X2Y capacitor 20. Utilizing stampings for the circuit connections and incorporating them into the motor connector 10 is a feature of the embodiment. The assembly can be assembled using automation or manual assembly utilizing low cost components. This invention can be use on any motor with a multitude of poles, and brushes and will be placed near the input power source. The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Motor RFI Suppression is commonly completed by the use of a multitude wire wound inductors in series with the brushes and a film or ceramic capacitor in parallel to the power supply source. An improved RFI suppression package, based on new technology of the X2Y component, is needed. Details of the X2Y can be found at http://www.x2y.com. An X2Y component is a four terminal device with unique architecture. X2Y is based on a standard bypass capacitor as a foundation provided with additional “reference” electrodes and two side terminations, called G 1 (ground) and G 2 , which are attached to the reference electrodes. Inserting parallel reference electrodes inside the bypass capacitor by dividing an unbalanced single end device, a balanced device is created. A balanced device is composed of two nominally identical halves. The main benefits of balance are: Two tight tolerance “Y” capacitors (1-2.5%); Temperature variation effects elimination; Voltage vs. capacitor variation becomes equalized line-to-line. FIG. 1 shows a conventional X2Y component or capacitor 11 where two side terminations (G 1 and G 2 ) attached to the reference electrodes results in acquiring one package consisting of the three capacitors. Cx is a capacitor between power lines and Cy is a capacitor between one power line and ground. The X2Y configuration is similar to a dual rectangular coaxial structure. An internal Faraday cage forms a shielded container for each conductor (+Bat and −Bat) inside the capacitor. At high frequency, the circuit noise in each capacitor will choose the low impedance path of the shield and opposing noise current will be cancelled. Inside the X2Y component, every other layer within the single component body is in opposition to cancel the magnetic fields. The components circuit inside operates simultaneously in multi-modes (Common and Differential Mode Noise Coupling). X2Y components reduce Electro-magnetic Interference (EMI) by means of field cancellation. By contrast, standard components are using capacitance to shunt noise or inductors to block noise with high impedance. X2Y components are in by-pass and effectively filtering only the noise. Because they are in by-pass X2Y components do not heat up like standard components. The way the X2Y component is attached and placed can have major effects on how well it performs. Some special study and experimental research have been done to get maximum broadband filtering performance. There is a need to provide an X2Y capacitor in a motor connector for Radio Frequency Interference (RFI) suppression.
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<SOH> SUMMARY OF THE INVENTION <EOH>An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by providing a connector structure for a brush motor. The connector structure includes a connector body associated with the motor. An X2Y capacitor structure is provided. A positive power terminal connection structure is associated with the connector body and is electrically connected with the capacitor structure and is constructed and arranged to electrically engage a positive power terminal of the motor. A negative power terminal connection structure is also associated with the connector body. The negative power terminal connection structure is electrically connected with the capacitor structure and is constructed and arranged to electrically engage a negative power terminal of the motor. A ground connection structure is electrically connected with the capacitor structure and is constructed and arranged to be electrically connected with a ground mass. Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.
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20040702
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20060328
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20051027
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60304.0
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DUVERNE, JEAN F
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MOTOR ASSEMBLY OF X2Y RFI ATTENUATION CAPACITORS FOR MOTOR RADIO FREQUENCY INTERFERENCE (RFI) AND ELECTROMAGNETIC COMPATIBILITY (EMC) SUPPRESSION
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UNDISCOUNTED
| 0
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ACCEPTED
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10,884,184
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ACCEPTED
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Liquid dispensing device and steam cleaner containing same
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A liquid dispensing unit for a steam cleaner with a hand grip for dispensing steam is provided. The liquid dispenser injects a liquid, such as soap, into the steam to be applied to the dirt or stain to be removed. The dispenser includes a housing with at least one liquid cleaning agent tank adapted to fit onto the nozzle connection of the cleaner hand grip. The liquid dispensing unit includes a manually controlled pump for controlling the amount of liquid cleaning agent injected into the steam. The dispenser housing includes a nozzle end for receiving the same cleaning attachments that fit onto the hand grip.
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1. A liquid dispensing unit, comprising: a housing with a fluid passage therethrough; at least one liquid storage reservoir mounted on the housing; a pump having an inlet conduit connected to the reservoir and an outlet conduit connected to the fluid passage; the inlet conduit for conveying the liquid from the storage reservoir to the pump, and the outlet passage for injecting liquid into the fluid in the fluid passage; and a pump button coupled to the pump for controlling the amount of liquid dispensed through the outlet conduit into the fluid passage. 2. The liquid dispensing unit of claim 1, wherein the liquid is a cleaning agent. 3. The liquid dispensing unit of claim 1, wherein the fluid passage carries steam. 4. The liquid dispensing unit of claim 1, wherein the pump includes a cylindrical chamber and a piston operatively displaceable in the chamber in response to movement of the pump button to release fluid into the fluid passage. 5. The liquid dispensing unit of claim 1, wherein the pump chamber includes a first one-way valve between the chamber and the inlet conduit, and a second one-way valve between the chamber and the outlet conduit. 6. The liquid dispensing unit of claim 1, wherein the housing includes a locking tab attachment for receiving attachments to the distal end thereof. 7. The liquid dispensing unit of claim 1, wherein the housing is adapted to engage a hand grip of a steam cleaner. 8. A liquid dispensing unit for a steam hand grip attachment of a steam cleaner, comprising: an elongated housing having a proximal inlet end and distal outlet end with a fluid conduit extending therethrough; the inlet end configured to receive the steam outlet end of the steam cleaner; a liquid reservoir mounted on the housing; a pump mounted on the housing with an inlet conduit connected to the fluid conduit; and a pump button for controlling the amount of liquid dispensed through the outlet conduit to the fluid conduit. 9. The liquid dispensing unit of claim 7, wherein the steam hand grip includes a trigger for controlling the amount of steam passing through the fluid conduit. 10. The liquid dispensing unit of claim 7, wherein the distal end of the housing includes a locking tab for selectively receiving steam cleaning attachments. 11. A steam cleaner including a liquid dispensing unit, comprising: a main body having a heating element, a water inlet and a steam outlet, and a steam hose connected to the outlet and a steam hand grip mounted on the distal end of the hose; a liquid dispensing unit mounted on the steam hand grip, the liquid dispensing unit including: a housing with a fluid passage therethrough; at least one liquid storage reservoir mounted on the housing; a pump having an inlet conduit connected to the reservoir and an outlet conduit connected to the fluid passage; the inlet conduit for conveying the liquid from the storage reservoir to the pump, and the outlet passage for injecting liquid into the fluid in the fluid passage; and a pump button coupled to the pump for controlling the amount of liquid dispensed through the outlet conduit into the fluid passage. 12. The steam cleaner of claim 11, wherein the liquid in the liquid dispensing unit is a cleaning agent. 13. The steam cleaner of claim 11, wherein the fluid passage carries steam. 14. The steam cleaner of claim 11, wherein the pump includes a cylindrical chamber and a piston operatively displaceable in the chamber in response to movement of the pump button to release fluid into the fluid passage. 15. The steam cleaner of claim 11, wherein the pump chamber includes a first one-way valve between the chamber and the inlet conduit, and a second one-way valve between the chamber and the outlet conduit. 16. The steam cleaner of claim 11, wherein the housing includes a locking tab attachment for receiving attachments to the distal end thereof.
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BACKGROUND OF THE INVENTION The invention relates generally to a liquid dispensing device, and more particularly to a device for dispensing a controlled amount of liquid cleaner into a steam outlet of a steam cleaner. Steaming devices used to apply steam to household objects are well known. The uses of the devices vary widely, and may include the application of steam to drapes or other fabrics to ease wrinkles, and the application of steam to objects to assist in cleaning the objects. Typical steam devices have a reservoir for storing water with a heating element to heat the water. The heated water generates steam, which may be directed towards its intended destination through a nozzle which controls the application of the steam. Variation of the shape and size of the nozzle allows for preferred distribution of generated steam to an object to be cleaned. The nozzles may be disconnectable from the steam generator to allow different nozzles to be utilized, based on the object to be steamed. The nozzle may be either closely coupled to the steam generator, or located at a distance from the steam generator, requiring tubing or other steam transfer structures to be interconnected between the steam generator and the discharge nozzle. Typically, it is beneficial to provide suitable connectors between the steam generator and the nozzle to allow either the nozzle to be connected to the steam generator, or to allow the interpositioning of transfer tubes or hoses between the steam generator and the nozzle. The use of steam alone sometimes is not sufficient to clean an object or surface where the dirt and/or stain to be removed is particularly resistant to cleaning i.e. blood, wine, grass, tea, coffee and the like. In these cases, a cleaning agent in addition to steam may help facilitate in the removal of the dirt and/or stain. Further, an unregulated amount of cleaning agent and steam decreases the efficiency of the removal of the dirt and/or stain. This is because some dirt and/or stains need to be pretreated with the cleaning agent before applying the steam for the dirt and/or stain removal or vice versa. In addition, other dirt and/or stains may need just steam to remove or dislodge the dirt and/or stain. The unregulated release of steam generated by a steam generator reduces the efficiency with which the device may be operated. Such inefficiency arises from the generation of excess steam when the steam is not being applied to an object to be steamed. These inefficiencies increase the operating cost of the device, and decreases the utility of the device. The use of a cleaning agent and mixing it with steam to bring the mixture into contact with the dirt and/or stain to be removed is known in the art. However, such devices do not allow the user the option of applying the steam first to the object to be cleaned and then immediately applying a controlled amount of cleaning agent to the object to be cleaned. Further, the ratio of cleaning agent to steam needed for the removal of dirt and/or stain is not tailored by the user. A combined steam and vacuum cleaner is shown in U.S. Pat. No. 4,327,459. Here, a steam hose and a detergent hose deposit steam and detergent on a surface to be cleaned adjacent to a vacuum hose. In this device, a water reservoir and a detergent reservoir are provided in a canister. Another variation of a combined steam and vacuum cleaner is shown in United States published application No. 2002/0112744. Here, a liquid cleaning agent is injected into a steam compartment that is then applied to the surface to be cleaned through a steam spray head. The steam and soap are then removed by a suction nozzle adjacent to the steam spray head. A steam cleaning apparatus providing for injection of a cleaning agent into a fluid conduit carrying a hot stream of water, steam and combustion gases to form a cleaning jet is shown in GB 1,449,483. Notwithstanding the wide variety of steam generating appliances available, there exists the need to provide a self-contained liquid cleaning fluid dispenser device for use with a steam cleaner, particularly for a light-weight portable device suitable for household use. It is desirable to provide this device with the ability for a user to control the amount of steam so that a small amount of cleaning agent is injected into the steam without lowering the quality of the steam making the device suitable for cleaning household items. SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, a liquid dispensing unit suitable for injecting a controlled amount of liquid, such as a liquid soap agent into the outlet of a steam cleaning device as steam is applied to an object to be cleaned is provided. The steam generating device includes a water reservoir with a heating element for generating steam that is controlled by a hand grip that regulates the amount of steam fed to a nozzle, rigid pipe or an appliance piece mounted on the pipe or nozzle. The liquid dispensing unit includes a liquid reservoir mounted on the hand grip with a user operated pump for controlling the amount of liquid dispensed into the steam pipe upstream of the steam outlet. In one embodiment, the liquid dispensing unit includes a mechanical pump having a chamber with a trigger connected to a piston that is biased away from the bottom of the chamber by a spring. When the user depresses the trigger, the piston is pushed against the spring injecting liquid into the steam pipe. When the piston is released and moves back to its original position, additional fluid is drawn from the storage tank into the chamber. Accordingly, it is an object of the invention to provide an improved liquid dispensing unit. Another object of the invention is to provide an improved liquid dispensing unit for a steam cleaner for controlling the amount of liquid injected into the steam outlet. A further object of the invention is to provide an improved liquid dispensing unit for a steam cleaner where a user controls the amount of steam and liquid cleaning agent dispensed in the steam outlet or nozzle. Yet another object of the invention is a liquid cleaning dispensing unit that can be selectively added to a hand-held steam cleaning hand grip. Yet a further object of the invention is to provide a liquid cleaning dispensing unit that allows addition of steam cleaning appliances. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. The invention accordingly comprises a product possessing the features, properties, and the relation of components which will be exemplified in the product hereinafter described, and the scope of the invention will be indicated in the claims. BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is made to the following description taken in connection with the accompanying drawing(s), in which: FIG. 1 is a perspective view of a steam cleaning device suitable for use with a liquid dispensing unit in accordance with the invention; FIGS. 2a and 2b are perspective views of the hand grip of the steam cleaner of FIG. 1 showing the locking button and how an appliance is attached; FIG. 3 is a cross-sectional view of the hand grip of FIG. 2; FIG. 4 is a perspective view of a liquid dispensing unit constructed and arranged in accordance with the invention; FIG. 5 is a perspective view of the liquid dispensing unit of FIG. 4 and how it attaches to the hand grip of FIG. 3; FIG. 6 is a perspective view of the liquid dispensing unit of FIG. 4 attached to the steam cleaner hand grip; FIG. 7 is a perspective view of the hand grip and dispensing unit with an appliance attached to the liquid dispensing unit; and FIG. 8 is a schematic cross-sectional elevational view of a liquid dispensing unit constructed and arranged in accordance with the invention to be mounted on a steam cleaner hand grip of the type shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a perspective view of a steam cleaning device 11 including a main body 12 and a steam release hand grip 13 coupled to main body 12 by a flexible hose 14 and a steam outlet 15. A liquid dispensing attachment 51 is mounted on the distal nozzle end of hand grip 13 (see FIG. 6). Liquid dispensing device 51 includes a steam inlet 19 at the proximal end, a liquid reservoir 57 mounted on the bottom, and a steam outlet 51b for dispensing steam mixed with liquid stored in reservoir 57. Outlet 51b is the same configuration as outlet 15 to hand grip 13 that will be described in more detail in connection with hand grip 13 shown in detail in FIG. 2. This allows for installation of the same attachments, such as brushes and nozzle, to dispensing device 51 as outlet 51b of hand grip 13. Main body 12 of steam cleaning device 11 includes a water inlet 22 and an internal water reservoir 17 with heating elements connected to a power source by a power cord 21. Steam generated in reservoir 17 exits by steam outlet 23 with flexible hose 14 coupled thereto. Main body 12 is outfitted with a handle 24 and a strap 26 for conveniently lifting and carrying main body 12. Main body 12 also includes an on/off switch 27 and an indicator light 28 to indicate when steam temperature is appropriate for use. Once water has been heated sufficiently to generate steam within main body 12, a user may selectively release steam by operation of hand grip 13. Hand grip 13 is illustrated in more detail in FIG. 2a and in cross-section in FIG. 3. Hand grip 13 has an internal cavity 34, and is elongated and curved for conveniently fitting within the hand of a user. Hand grip 13 includes a proximal inlet end 32 having a fitting for securing flexible hose 14 and a distal outlet end 31 for securing a nozzle or additional attachments, such as brushes or nozzles. In accordance with the invention, liquid cleaner dispenser 51 is mounted in the same manner as will be described in more detail below. Hand grip 13 is fitted with a trigger 36 for selectively releasing and controlling the amount of steam fed to outlet end 31. In connection with the type of steam cleaner 11 set forth for purposes of illustration, steam generated by main body 12 passes through a steam conduit 37 coupled to a valve 38 within cavity 34 operated by squeezing trigger 36. When trigger 36 is squeezed, steam in conduit 37 passes through valve 38 and is released through a valve outlet 41 and a steam outlet conduit 42 that extends to outlet end 31. A spring tab 43 is located at the distal end of hand grip 13 for allowing attachments to be placed at outlet end 31 and secured to hand grip 13. Tab 43 is positioned within an opening 44 in the upper portion of hand grip 13 and biased upwardly to extend above the upper surface of hand grip 13. Tab 43 is configured to fit within a corresponding opening within an attachment. This is illustrated and described in more detail in connection with an attachment such as a hose 20 having a button hole 20a shown in FIG. 2b for receiving tab 43. Referring now to FIG. 4, a liquid dispensing unit 51 constructed and arranged in accordance with the invention is shown. Dispensing unit 51 is elongated, formed of substantially rigid plastic material having a proximal inlet end 511a and a distal outlet end 51b, and has a button hole 53 to engage locking tab 43 on distal end of hand grip 13. Unit 51 is formed with a proximal inlet end 51a for receiving distal end 31 of hand grip 13 with tab 43 fitting into a hole 53 formed at the top of unit 51 to engage unit 51 on hand grip 13 so the units will function as one. Unit 51 is formed with a distal outlet end and nozzle connection 51b that is identical with distal nozzle end 15 of hand grip 13. This allows addition of additional cleaning attachments, such as brushes and hoses or rigid pipes to distal outlet end 51b of unit 51. In this case, when liquid soap is dispensed into steam exiting outlet end 51b, it will then pass through the additional cleaning attachments mounted thereon. FIG. 5 shows how liquid dispensing unit 51 is attached to locking button 43 of hand grip 13. Once attached as shown in FIG. 6, locking button 56 on unit 51 is available for attaching a steam cleaning attachment of the same type that may be attached directly to hand grip 13. Suitable attachments include steam concentrators, bristle brushes, wallpaper scrapers, squeegees and the like. This makes the steam cleaner suitable for a wide variety of chores requiring the additional cleaning benefits of soap in combination with steam. Locking projecting tab 56 is provided at distal end 51b of unit 51 for providing the locking engagement mechanism with these attachments. FIG. 7 shows one embodiment of the present invention where a bristle brush attachment 75 is mounted on liquid dispensing unit 51, which is mounted on stream hand grip 13. Brush attachment 75 has an opening 79 configured to engage locking tab 56 on the distal end 51b of the liquid dispensing unit 51. In accordance with the invention, unit 51 includes a liquid reservoir tank 57, in this case positioned at the bottom of unit 51, with a removable cap 58 for adding liquid cleaning fluid to reservoir 57. Unit 51 has a user operable release pump button 59 for injecting liquid stored in reservoir 57 into steam passing through a conduit 61 in liquid dispensing unit 51. Operation of pump button 59 will be described in detail in connection with FIG. 8. FIG. 8 shows in schematic a cross-sectional view of liquid dispensing unit 51 illustrated in FIG. 4. Steam allowed to exit hand grip 13 passes through elongated passageway 61 to nozzle end 54. Pump button 59 of liquid dispensing unit 51 is operatively coupled to a pump 62 having a cavity 63 and a piston 64 connected to button 59 by a shaft 66. A spring 67 is positioned within cavity 63 biasing piston 64 upwardly. A one-way inlet valve 68 is located at the lower end of cavity 63 with an inlet conduit 69 extending from reservoir 57. An one-way outlet valve 71 is located in the sidewall of cavity 63. An outlet conduit 72 connects one-way outlet valve 71 to steam conduit 61. This control is mechanical; however, it is within the scope of the invention to utilize electrical controls. During operation, after button 59 is depressed and released, spring 67 biases piston 64 upwardly to fill cavity 63 with liquid from reservoir 57. When it is desired to inject cleaning fluid into conduit 61 to mix with the steam, button 59 is depressed forcing liquid cleaning fluid out outlet one-way valve 71 through conduit 72 into steam conduit 61. Here, liquid cleaning fluid from cavity 63 is injected into steam passing to outlet 51b directly onto the surface to be cleaned or through an optional attachment coupled thereto. The diameter of the proximal end of conduit 61 of the liquid dispensing unit 51 is larger than the passageway 42 of the steam hand grip attachment 13 so that a tight connection can be formed between the conduit 61 of the liquid dispensing unit 51 and the passageway 42 of the steam hand grip attachment 13. A secure locking engagement of tab 56 with a spring allows a variety of cleaning nozzles to be engaged to the liquid dispensing unit 51 when assembled for use. The liquid in reservoir 57 to be injected into the steam may be any suitable liquid cleaning agent such as soap or solvent, preferably, the liquid soap is fully miscible with water and bio-degradable. The solvents include cleaning solutions and degreasers. Liquid dispensing unit provides many advantages over known steam cleaning devices. Here, a controlled and small amount of soap is selectively added to the steam outlet. This allows the surface to be steamed initially, soaped and steam added for increased cleaning, and then the soap rinsed from the cleaned surface by steam alone. The internal mechanism of the hand grip does not encounter the soap that is slowly injected into the steam being fed to the nozzle, pipe or appliance attached to the hand grip. Thus, there is no potential to clog or foul the steam release trigger mechanism. By injecting small amounts of liquid soap, the temperature and quality of the steam are not lowered. It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above product without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes of the invention. Accordingly, reference should be made to the appended claims, rather than the foregoing specification, as indicating the scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The invention relates generally to a liquid dispensing device, and more particularly to a device for dispensing a controlled amount of liquid cleaner into a steam outlet of a steam cleaner. Steaming devices used to apply steam to household objects are well known. The uses of the devices vary widely, and may include the application of steam to drapes or other fabrics to ease wrinkles, and the application of steam to objects to assist in cleaning the objects. Typical steam devices have a reservoir for storing water with a heating element to heat the water. The heated water generates steam, which may be directed towards its intended destination through a nozzle which controls the application of the steam. Variation of the shape and size of the nozzle allows for preferred distribution of generated steam to an object to be cleaned. The nozzles may be disconnectable from the steam generator to allow different nozzles to be utilized, based on the object to be steamed. The nozzle may be either closely coupled to the steam generator, or located at a distance from the steam generator, requiring tubing or other steam transfer structures to be interconnected between the steam generator and the discharge nozzle. Typically, it is beneficial to provide suitable connectors between the steam generator and the nozzle to allow either the nozzle to be connected to the steam generator, or to allow the interpositioning of transfer tubes or hoses between the steam generator and the nozzle. The use of steam alone sometimes is not sufficient to clean an object or surface where the dirt and/or stain to be removed is particularly resistant to cleaning i.e. blood, wine, grass, tea, coffee and the like. In these cases, a cleaning agent in addition to steam may help facilitate in the removal of the dirt and/or stain. Further, an unregulated amount of cleaning agent and steam decreases the efficiency of the removal of the dirt and/or stain. This is because some dirt and/or stains need to be pretreated with the cleaning agent before applying the steam for the dirt and/or stain removal or vice versa. In addition, other dirt and/or stains may need just steam to remove or dislodge the dirt and/or stain. The unregulated release of steam generated by a steam generator reduces the efficiency with which the device may be operated. Such inefficiency arises from the generation of excess steam when the steam is not being applied to an object to be steamed. These inefficiencies increase the operating cost of the device, and decreases the utility of the device. The use of a cleaning agent and mixing it with steam to bring the mixture into contact with the dirt and/or stain to be removed is known in the art. However, such devices do not allow the user the option of applying the steam first to the object to be cleaned and then immediately applying a controlled amount of cleaning agent to the object to be cleaned. Further, the ratio of cleaning agent to steam needed for the removal of dirt and/or stain is not tailored by the user. A combined steam and vacuum cleaner is shown in U.S. Pat. No. 4,327,459. Here, a steam hose and a detergent hose deposit steam and detergent on a surface to be cleaned adjacent to a vacuum hose. In this device, a water reservoir and a detergent reservoir are provided in a canister. Another variation of a combined steam and vacuum cleaner is shown in United States published application No. 2002/0112744. Here, a liquid cleaning agent is injected into a steam compartment that is then applied to the surface to be cleaned through a steam spray head. The steam and soap are then removed by a suction nozzle adjacent to the steam spray head. A steam cleaning apparatus providing for injection of a cleaning agent into a fluid conduit carrying a hot stream of water, steam and combustion gases to form a cleaning jet is shown in GB 1,449,483. Notwithstanding the wide variety of steam generating appliances available, there exists the need to provide a self-contained liquid cleaning fluid dispenser device for use with a steam cleaner, particularly for a light-weight portable device suitable for household use. It is desirable to provide this device with the ability for a user to control the amount of steam so that a small amount of cleaning agent is injected into the steam without lowering the quality of the steam making the device suitable for cleaning household items.
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<SOH> SUMMARY OF THE INVENTION <EOH>Generally speaking, in accordance with the invention, a liquid dispensing unit suitable for injecting a controlled amount of liquid, such as a liquid soap agent into the outlet of a steam cleaning device as steam is applied to an object to be cleaned is provided. The steam generating device includes a water reservoir with a heating element for generating steam that is controlled by a hand grip that regulates the amount of steam fed to a nozzle, rigid pipe or an appliance piece mounted on the pipe or nozzle. The liquid dispensing unit includes a liquid reservoir mounted on the hand grip with a user operated pump for controlling the amount of liquid dispensed into the steam pipe upstream of the steam outlet. In one embodiment, the liquid dispensing unit includes a mechanical pump having a chamber with a trigger connected to a piston that is biased away from the bottom of the chamber by a spring. When the user depresses the trigger, the piston is pushed against the spring injecting liquid into the steam pipe. When the piston is released and moves back to its original position, additional fluid is drawn from the storage tank into the chamber. Accordingly, it is an object of the invention to provide an improved liquid dispensing unit. Another object of the invention is to provide an improved liquid dispensing unit for a steam cleaner for controlling the amount of liquid injected into the steam outlet. A further object of the invention is to provide an improved liquid dispensing unit for a steam cleaner where a user controls the amount of steam and liquid cleaning agent dispensed in the steam outlet or nozzle. Yet another object of the invention is a liquid cleaning dispensing unit that can be selectively added to a hand-held steam cleaning hand grip. Yet a further object of the invention is to provide a liquid cleaning dispensing unit that allows addition of steam cleaning appliances. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. The invention accordingly comprises a product possessing the features, properties, and the relation of components which will be exemplified in the product hereinafter described, and the scope of the invention will be indicated in the claims.
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20040702
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20090113
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20060105
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63405.0
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A47L514
| 1
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WILSON, LEE D
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LIQUID DISPENSING DEVICE AND STEAM CLEANER CONTAINING SAME
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UNDISCOUNTED
| 0
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ACCEPTED
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A47L
| 2,004
|
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10,884,187
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ACCEPTED
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System and method for creating and navigating a linear hypermedia resource program
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A method and system for creating and navigating linear hypermedia resource programs are disclosed. The system includes a distributed hypermedia resource network having a plurality of hypermedia resources residing on one or more remote information nodes. A common remote information node is in communication with a subscriber station and the remote information nodes in the distributed network. The common remote information node contains at least one linear hypermedia resource program consisting of pre-selected media elements from one or more hypermedia resources linked with exclusive linear links, each media element in the linear program having only one forward link to the next media element. The method includes the steps of downloading and displaying a media element in the linear program and responding to user commands to download and display the next media element in the linear program.
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1. A computer readable medium having computer executable instructions for navigating a linear Web tour on the World-Wide Web, the linear Web tour including a plurality of websites at respective remote information nodes, the plurality of websites associated by a series of exclusive forward links, each website having a plurality of individual media elements, including a base media element, the computer executable instructions comprising instructions for: downloading and displaying a first base media element of a first website of the linear Web tour on a display device at a user location; responding to commands of a user to download and display selected individual media elements of the first website of the linear Web tour on the display device, the first website having an exclusive forward link to a second website of the linear Web tour; displaying a forward link button on the display device; receiving a first signal in response to an action of the user indicating an activation of the forward link button; downloading and displaying a second base media element of the second website on the display device; and responding to commands of a user to download and display selected individual media elements of the second website of the linear Web program on the display device at the user location, the second website having an exclusive forward link to a third website of the linear Web tour. 2. (canceled) 3. The computer readable medium of claim 1 wherein the instructions for responding to commands of a user to download and display selected individual media elements of the first website comprise instructions for displaying the selected individual media elements of the first website in a framed window. 4. The computer readable medium of claim 3 wherein the instructions for displaying the forward link button comprise instructions for displaying the forward link button outside of the framed window. 5. The computer readable medium of claim 4 further comprising instructions for: displaying to the user a plurality of indicators, each indicator representative of a respective website of a selected portion of the linear Web tour. 6. The computer readable medium of claim 5 wherein the instructions for displaying to the user the plurality of indicators comprise instructions for displaying text indicative of the respective website. 7. The computer readable medium of claim 5 further comprising instructions for: receiving a second signal in response to an action of the user indicating selection of a selected website of the selected portion of the Web tour; downloading and displaying a base media element for the selected website on the display device; and responding to commands of a user to download and display selected individual media elements of the selected website of the linear Web tour on the display device at the user location. 8. The computer readable medium of claim 7 wherein the instructions for receiving the second signal comprise instructions for recognizing an action of the user to select an indicator corresponding to the selected website. 9. The computer readable medium of claim 1 wherein the second website comprises a home page and wherein the instructions for responding to commands of a user to download and display selected individual media elements of the second website includes instructions for displaying the home page of the second website. 10. The computer readable medium of claim 1 wherein the instructions for responding to commands of a user to download and display selected individual media elements of the first website comprise instructions for downloading selected individual media elements stored at a remote information node. 11. The computer readable medium of claim 10 wherein the instructions for responding to commands of a user to download and display selected individual media elements of the second website comprise instructions for downloading the selected individual media elements of the second website from a second remote information node. 12. The computer readable medium of claim 1 further comprising instructions for: displaying a back link button on the display device; and receiving a first signal in response to an action of the user indicating an activation of the back link button. 13. (canceled) 14. A computer readable medium having computer executable instructions for creating a linear Web tour comprising a linear linked-sequence of program elements on the World-Wide Web, the World-Wide Web including a plurality of websites at respective remote information nodes, each website having a plurality of individual media elements, the computer executable instructions comprising instructions for: selecting a first base media element corresponding to a first Web page; selecting a second base media element corresponding to a second Web page; and incorporating the first base media element and the second base media element as program elements in the linear linked-sequence of program elements. 15-16. (canceled) 17. The computer readable medium of claim 14 further comprising instructions for: editing a location of program elements of the linear linked-sequence of program elements. 18. (canceled) 19. A computer readable medium having computer executable instructions for navigating a linear Web tour comprising information obtained on the World-Wide Web, the linear Web tour including a plurality of Web pages from websites at respective remote information nodes, the plurality of Web pages cached at a common remote information node and websites associated by a series of exclusive forward links, each website having a plurality of individual media elements, including a base media element, the computer executable instructions comprising instructions for: downloading from the common remote information node to a user location a first of the plurality of Web pages cached at the common remote information node, the first Web page associated with a base media element of a first website of the linear Web tour; displaying the first Web page on a display device at the user location; responding to commands of a user to download and display selected individual media elements of the first website of the linear Web tour on the display device, the first Web page having an exclusive forward link to a second of the plurality of Web pages of the linear Web tour cached at the common remote information node; displaying a forward link button on the display device; receiving a first signal in response to an action of the user indicating an activation of the forward link button; and in response to a user activation of the forward link button, downloading from the common remote information node to the user location and displaying a second Web page of the linear Web tour, the second Web page associated with a second website of the linear Web tour, wherein the forward link button activates the exclusive forward link regardless of which individual media element is currently displayed at the user location. 20. The computer readable medium of claim 19 wherein the instructions for responding to commands of a user to download and display selected individual media elements of the first website comprises instructions for displaying the selected individual media elements of the first website in a framed window. 21. The computer readable medium of claim 19 wherein the instructions for displaying the forward link button comprises instructions for displaying the forward link button outside of the framed window. 22. The computer readable medium of claim 19 further comprising instructions for displaying to the user a plurality of indicators, each indicator representative of a respective website of a selected portion of the linear Web tour. 23. The computer readable medium of claim 21 further comprising instructions for displaying media elements in a first region of the display device and for displaying the forward link button in a second region of the display device, wherein displaying the forward link button comprises persistently displaying the forward link button on the display device in the second region.
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RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 09/964,104, filed Sep. 26, 2001, which is a continuation of U.S. application Ser. No. 09/680,899, filed Oct. 6, 2000, now U.S. Pat. No. 6,330,596, which is a continuation of U.S. application Ser. No. 09/167,514, filed Oct. 6, 1998, now U.S. Pat. No. 6,145,000, and the entirety of each of these applications is incorporated herein by reference. BACKGROUND OF THE INVENTION The World Wide Web (the “Web”) provides an alternative source of information for consumers and business users. Some users also view the Web as a source of entertainment. Surfing the Web, cybercafes, etc. appeal to the sophisticated Web user as a way of having a good time. Many Americans raised in the television age view entertainment as a serial event. Specifically, generations of viewers have experienced television shows, movies, radio programs, and concerts which all proceed linearly from a beginning to an end. Some potential Web users of this generation view surfing the Web as intimidating from perhaps two respects: (1) the use of technology; and (2) the increasingly unorganized, virtually unlimited number of choices that are available. The Web is not inherently a linear entertainment medium. A Web user may typically go directly from any given site to a large number of other sites. At best, some websites provide links to similar sites, however they typically do not offer more than a cursory indication of what the linked sites contain. In addition, even sophisticated Web users are often frustrated by the amount of useless, undesirable material that appears on the Web. Take, for example, a user who wishes to look at pictures of classic automobiles. A search on classic automobiles may yield 10,000 hits. A website-by-website search for interesting material may yield many sites that do not meet the user's expectations as to the content, properties or quality. Some sites may be a single page that prompts a user to order a catalog. Other sites may have text but no pictures. Accordingly, there is a need for creating entertaining Web programs that appeal to a wide cross section of potential viewers. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of a system for use in creating and navigating a linear hypermedia resource program according to a preferred embodiment. FIG. 2 illustrates hypermedia resources that may reside on information nodes in the distributed hypermedia network of FIG. 1. FIG. 3 diagrammatically illustrates a linear hypermedia resource program and the selected base media elements in each of the desired hypermedia resources of the hypermedia resource data network. FIG. 4 illustrates a user interface for use in navigating a hypermedia resource program in accordance with one embodiment of the present invention. FIG. 5 is a flow diagram of a method for navigating a linear hypermedia resource program. FIG. 6 is a flow diagram illustrating an alternative method for navigating a linear hypermedia resource program in accordance with one embodiment of the present invention. FIG. 7 illustrates a user interface for prompting a user for an experience level in accordance with one embodiment of the present invention. FIG. 8 illustrates a method of generating a linear hypermedia resource program utilizing the system of FIG. 1 in accordance with one embodiment of the present invention. FIG. 9 illustrates an alternative embodiment of a method of generating linear hypermedia resource program. FIG. 10 is a flow diagram illustrating a third embodiment of a method for generating a linear hypermedia resource program. FIG. 11 is a flow diagram illustrating a fourth embodiment of a method for generating a linear hypermedia resource program. FIG. 12 is a flow diagram of a method for generating a linear hypermedia resource program in billing a user. FIG. 13 diagrammatically illustrates one preferred embodiment of navigating a linear hypermedia resource program. FIG. 14 diagrammatically illustrates one preferred embodiment of a method for creating a linear hypermedia resource program. FIG. 15 illustrates an alternative embodiment of a method for creating a linear hypermedia resource program. DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS The present invention addresses the need for creating and navigating entertaining Web programs that filter out unwanted information and present desired information in a series of linearly linked websites. In one embodiment of the present invention, a user starts with the first site and in a guided tour fashion, when finished, is directed exclusively to the second site. When done with the second site, the user is directed exclusively to the next site, etc. The progression of sites defines a programmed linear hypermedia resource path that is geared towards the entertainment of the user. Users may also implement the system and method described in more detail below for educational purposes or as a research tool. Referring to FIG. 1, a system 10 for use in navigating and generating a linear hypermedia resource program is shown. The system 10 includes a distributed hypermedia data network 12 having a plurality of information nodes 14 and a common remote information node 16 all in communication with each other. A subscriber station 18 is in communication with the common remote information node 16 over a communication line. In one embodiment, the distributed hypermedia data network 12 may be the Web where the information nodes and common remote information node 14, 16 are servers, memory devices, personal computers, or the like that are capable of storing, processing, and exchanging data with other information nodes. The subscriber station 18 may be a personal computer or other device having capability of communicating with the common remote information node 16 and presenting audio, visual, or tactile information received from the common remote information node 16. As shown in FIG. 2, each information node may contain a plurality of hypermedia resources 20. Each hypermedia resource 20 contains a plurality of individual media elements 22, including a base media element 24, that are associated by an indexed tree 21. In one embodiment, each hypermedia resource 20 may be a website on the Web. The base media element 24 can comprise a selected Web page of the website that serves as a logical entry point to the website. The plurality of other media elements 22 can include the additional pages of the website along with other media that may include audio and video clips and, optionally, tactile records that are convertible to tactile information by means of a user interface device that includes tactile or force feedback. Each of the information nodes 14 in the distributed hypermedia data network 12 may contain one or more hypermedia resources 20. Unlike a typical search result from an Internet search engine on the Web, a linear hypermedia resource program includes a selected group of media elements that are associated by a series of exclusive forward and backward links that are, in one embodiment, accessible at all times as the hypermedia resources are browsed. FIG. 3 pictorially represents an embodiment of a preferred linear hypermedia resource program in the context of the media element or elements in hypermedia resources connected by the linear hypermedia resource program 23. As shown in FIG. 3, a linear program may include a selected base media element from each of a number of hypermedia resources of interest. Each base media element 24 is placed in a particular program element 25 in the linear hypermedia resource program 23 such that the program will move the user between hypermedia resources in a predetermined manner along an exclusive chain of linear links 27, each selected base media element having one exclusive forward link and one exclusive backward link. Each program element 25 maybe a media element 22 from a hypermedia resource 20. In one embodiment, the program element 25 maybe the universal resource locator (URL) for each selected media element 24. In an alternative embodiment, each program element 25 may be the entire content of a base media element 24. Preferably, the program elements 25 of a linear hypermedia resource program 23 are stored in the common remote information node 16 controlled by the internet service provider used by a subscriber at a subscriber station 18 (FIG. 1). To accelerate the accessibility of each program element in a linear hypermedia resource program, each program element is preferably fully cached in the common remote information node so that all the information of the media element comprising each program element is retrieved prior to executing the linear hypermedia resource program. In this manner, variations in communication speeds between the common remote information node 16 and the information nodes 14 containing selective hypermedia resources are minimized. As mentioned above, each media element making up a program element may contain textual, visual, audio and tactile information. The program elements 27 of the linear hypermedia resource program may each come from a different hypermedia resource, the same hypermedia resource, or a combination of the two. FIG. 4 illustrates a preferred embodiment of a user interface operable by a user at a subscriber station 18 to view a linear hypermedia resource program. Preferably the user interface 28 comprises a collection of areas 30, 32, 34 that each provide a user with separate functionality. A map area 30 displays information representative of media elements in the linear program for all or a portion of the media elements 22 in the order arranged in the linear hypermedia resource program. This information representative of the media elements that make up the program elements of the linear program may be text, icons, graphical depictions or other indicators capable of conveying the subject of the represented media element. The map area 30 may display the entire linear path comprised of all the elements in the linear program or simply a linear segment 31 of the entire linear path. A display area 32 shows the contents of a selected media element in the linearly linked chain of the hypermedia resource program. A command area 34 preferably contains backward and forward directional buttons 36 that allow a user to send signals to the common remote information node to change the media element displayed in the display area 32 to a subsequent or previous media element in the linear hypermedia resource program as shown in the map area 30. In one embodiment of the present invention, any or all of the areas 30, 32 and 34 are implemented using Web frames. Dynamic pages that utilize templates and tables are alternative implementations of the areas 30, 32 and 34 described above. Utilizing the system of FIGS. 1-2 and 4, methods for navigating and creating a linear hypermedia resource program are described below. Referring to FIG. 5, one preferred embodiment of a method of navigating a linear hypermedia resource program is shown. A user may download and display a first base media element in the linear hypermedia resource program (at step 38). In one embodiment, the contents of each program element of the linear hypermedia resource program are cached in memory at the common remote information node. The system, via the user interface 28, responds to additional user commands to download and display other media elements of the first hypermedia resource (at step 40). Although the entire hypermedia resource from which one or more media elements were preselected as program elements may also be cached at the common remote information node 16, the media elements that do not make up the linear hypermedia resource program are preferably accessed using links to the respective remote information node containing the hypermedia resource. A forward direction button 36 is displayed to the user on the display device of the subscriber station 18 and the subscriber station receives a first signal in response to an action of the user that indicates an activation of the forward link button (at steps 42, 44). If a signal is received indicating that the user has selected the forward directional button, a second base media element is downloaded and provided to the subscriber station (at step 46). As with the first hypermedia resource, the user may download and display selected media elements from the second hypermedia resource until satisfied (at step 48). The steps of responding to the user command to display a base media element of a hypermedia in a linear hypermedia resource program and, in response to subsequent commands of a user, to download and display other media elements from that hypermedia resource may be repeated many times. In this fashion, the user can traverse all of the program elements of the linear hypermedia resource program including all of the base media elements and any desired media elements of each hypermedia resource. By way of an example for implementing the method described above and shown in FIG. 5, consider a linear hypermedia resource program directed to hypermedia resources on the Internet related to a television celebrity. In this example, the linear hypermedia resource program 23 is an Internet Web path implemented by a internet service provider at a common remote information node 16. The user starts on the Web path at the first website, for example, a website showing a type of automobile driven by the celebrity along with specifications and prices. The presentation of the website is within the display area 32 of the user interface 28. Outside the display area 32, a map area 30 showing other sites along the celebrity Web path is displayed and identifies the current site. In one embodiment of the present invention, a map of the entire linear path is presented. In an alternative embodiment, a selected linear segment 31 of the map is shown. In this fashion, the user (by means of map zoom-in and zoom-out buttons not shown) can select a portion of the map of selected size to view by zooming into a particular site and reviewing it with more detail or zooming out and reviewing the map with more sites but with optionally less detail being displayed per site. In a further alternative, a user, by means of highlighting and selecting a particular program element from the map area 30, can selectively skip forward or backward to a particular program element and its corresponding base media element. The user can activate the forward direction button 36 to go to a second website on the tour. The second website may display subject matter relevant to the real life of, or a movie character portrayal by, the celebrity. If, for example, the celebrity was known to smoke cigars, a cigar store website having a variety of cigars for sale via mail order can be displayed. As the user progresses through the linear program, the user may come across a website having little appeal to the user and so the user may simply hit the forward direction button 36 to proceed along to the next in the serially linked series of websites. In addition, a skip next button (not shown) can likewise allow a user to skip the next program element in the linear program 23 and proceed directly to the program element after the next program element. The remaining program elements 25 in the linear program 23 can include website pages for Broadway plays the celebrity acted in, vacations in exotic locations associated with the celebrity, pictures of the celebrity in favorite roles, and so on. It should be noted that, in one embodiment of the present invention the user is free to engage hyperlinks that are present in each hypermedia resource. This allows the user to browse any of the individual hypermedia elements of the hypermedia resource as well as other linked hypermedia resources that may not be on the linear path. In this embodiment, the activation of the forward or back buttons directs the user to the next or previous hypermedia resource, respectively, and therefore allows the user to return to the path provided by the linear program 23. FIG. 6 shows an alternative embodiment of the method illustrated in FIG. 5. In this embodiment, the common remote information node 16 solicits the user for an experience level. The user interface 28 preferably contains a user experience level screen 50 that inquires as to a user's experience level in browsing hypermedia resources such as the Web. The experience level screen 50 provides an experience level menu having multiple experience level indicators 52 (see FIG. 7). In the embodiment of FIG. 6, the system displays the experience level menu and receives a desired experience level instruction from the user (at steps 54, 56). Upon receipt of the selected experience level, the common remote information node modifies the set of available commands to accord with the desired experience level (at step 58). In one embodiment, selection of a beginner experience level disables all links appearing on media elements in the linear hypermedia resource program. This feature discourages users from leaving the path defined by the program and becoming lost in cyberspace. In an alternative embodiment, the step of modifying the set of available commands may include disabling Web links between hypermedia resources 20 and only allowing a user to peruse media elements 22 within a selected hypermedia resource 20 until the next hypermedia resource 20 in the linear hypermedia resource program is selected through the forward or back direction buttons 36 in the user interface 28. After selecting the experience level and modifying the set of available commands, the method proceeds in much the same way as described in FIG. 5. The system downloads and displays a first base media element (at step 60) and downloads and displays selected media elements from the first hypermedia resource per user commands (at step 62). The node 16 displays the forward and back buttons 36 (at step 64) and displays the linear program map 30 on the user interface 28 (at step 66). The node 16 waits to receive a next signal from the user (at step 68) and displays the second base media element of the second hypermedia resource in a linear hypermedia program if a first signal is received (at step 70). The common remote information node 16 will then download and display selected media elements from the second hypermedia resource as directed by user commands received at the user interface (at step 72). The user then may decide to use the back button to send the signal to the system that returns to the previous hypermedia resource (at step 74). Alternatively, if after displaying the first base media elements of the first hypermedia resource the user selects an alternative command such as by selecting a particular program element from the map area 30, the system recognizes that command and downloads and displays the base media element that corresponds to the selected program element (at steps 76, 78). The system will subsequently download and display any selected hypermedia resources chosen by the user (at step 80). While FIG. 6 describes the operation of the present invention in the context of one embodiment including a first and second hypermedia resource, one of ordinary skill in the art, based on the teachings herein, will recognize that this method will similarly apply to a linear program 23 of arbitrary length. Further, while the step of displaying the linear program map is shown as a discrete step, the display of the program map can persist during the operation of the method described above and can be updated after each new program element is selected for displaying the user's position in the linear program. In addition, the back and forward command buttons can likewise be persistently displayed during the operation of the program. According to another aspect of the invention, in one embodiment a user at a subscriber station 18 may utilize software at the common remote information node 16 to generate a linear hypermedia resource program. As shown in FIG. 8, a user may be browsing a distributed hypermedia data network, such as the Web, and simply select a first base media element of a desired hypermedia resource (at step 82) and then proceed to select a base media element for a subsequent hypermedia resource (at step 84). The progression of selecting base elements for desired hypermedia resources may continue until the user has accumulated a desired number of base media elements. At the conclusion of selecting individual base media elements, the user is left with a sequence of exclusively linked hypermedia resources that may be saved for future perusal. Thus, the linear hypermedia resource program provides advantages over standard bookmark functions available on Internet Web browsers because an entire sequence of websites/Web pages having an exclusive linear path may be saved. Additionally, the entire content of each media element (such as a Web page) selected may be cached in a memory at the common remote information node operated by the internet service provider (ISP) to accelerate later retrieval of information. As shown in FIG. 9, an alternative embodiment of the method shown in FIG. 8 includes the ability to selectively place desired media elements in desired positions in the linear hypermedia program. Referring to FIGS. 9 and 10, a user may select the first base media element (at step 86) and then assign the first base media element to a first program element in the linear hypermedia program (at step 88). A second base media element may then be selected and assigned to a second program element of the linear hypermedia program (at steps 90, 92). Alternatively, a preferred embodiment allows the user to select a first base media element and provide an editing command to the system that assigns the first base media element to a selected program element position (at steps 94, 96). A later base media element can be selected and the system will receive a command to assign this later selected base media element to another selected program element position that may precede or follow the previously selected base media element in the linear hypermedia resource program 23 (at steps 98, 100). FIG. 11 shows another embodiment of a method for generating a linear hypermedia resource program. Rather than manually allowing a user to select media elements for inclusion in the linear program elements of the linear hypermedia resource program, a user may communicate search criteria to a linear hypermedia program service at a remote location. In one embodiment of the present invention, such as the celebrity application described above, Web paths may be created by a professional director from pre-existing or newly created websites or a combination of both. In an alternative embodiment, the Web paths may be created by an intelligent agent that operates independently of the user and responds to the user's suggested topics, likes and dislikes, as well as user preferences concerning content, properties and quality of websites. This service may be offered by the ISP at the common remote information node 16. When the search criteria are received at the node 16, the professional director or intelligent agent may evaluate media elements to select and organize, in an exclusive linearly linked fashion, highly relevant media elements satisfying the user's search criteria (at steps 102-108). For example, a user interested in shopping for furniture on the Web specifies the types of furniture in which he or she is interested (e.g., Chippendale breakfront mahogany china cabinets), and the type of websites desired (e.g., furniture stores with websites that show JPEG or MPEG images of the furniture with prices for each piece). Examples of other suitable file formats are any of a number of known graphics, video, audio and tactile data formats. Preferably, the user has the appropriate hardware and software at the subscriber station to interpret the electronic media element content into the video, audio, or tactile domain. A user also preferably designates file information content choices in the search criteria. File information content may be used to filter for Web pages that contain price listings or have the ability to place secure product orders via credit card. Many other file criteria may be used to select appropriate media elements. For example, a user can also specify that information must be presented in a certain language, that suitable websites must have been updated within a predetermined period, and so on. The user may optionally specify the time frame for generating a desired linear hypermedia resource program. For example, the user may request that the linear hypermedia resource program be ready by Friday night that week. The intelligent agent or professional director works off-line of the user to create a series of links that define a desirable path through a series of websites that meet the user's criteria. Once complete, the linear hypermedia resource program (in this example a serial path of website pages from one or more websites) is delivered to the user by HTTP or email. The common remote information node may automatically notify the user that the program is ready or may wait for the user to retrieve it. Internet service providers, or other linear hypermedia program sources offering users custom-made linear hypermedia resource programs, may offer linear hypermedia resource programs of different lengths and quality. In order to accommodate different needs and budgets, a method for generating a desired linear hypermedia resource program and accounting for billing information is useful. As FIG. 12 illustrates, a user at a subscriber station 18 initially sends a search request with specific search criteria to the common remote information node operated by the ISP (at step 110). The search criteria preferably include the time frame in which the user desires to receive the linear hypermedia program. A sliding scale of cost versus time, in the form of an algorithm or table stored in memory at the common remote information node, may then be applied to determine the final cost of generating the linear hypermedia resource program (at step 112). The media elements available in the distributed hypermedia data network are then analyzed in light of the search criteria (at step 114). As described above, the step of evaluating the media elements may be done with an intelligent agent such as a search engine with artificial intelligence capabilities, or may be done manually by personnel at the Internet service provider. Base media elements are then selected from the pool of relevant hypermedia resources and then assigned to program element positions in the linear hypermedia resource program (at step 116). The resulting linear hypermedia resource program is then transmitted from the common remote information node to the subscriber station (at step 118) and a billing record is also generated at the common remote information node of the Internet service provider in accordance with the time frame requested and scope of the search (at steps 120). Factors such as processor time, memory requirement for the linear program, or storage period at a server such as the common remote information node may also be incorporated into the billing record. FIGS. 13-15 provide a pictorial representation of a linear program, browsing a linear program, and the steps of creating a linear program. FIG. 13 best illustrates browsing the linear program depicted in FIG. 3. As indicated by link selection arrows 122, a user is allowed to browse media elements, other than the base media element stored in the linear program, in a hypermedia resource using existing Web browser type technology. Although a user may be viewing a media element other than the initial base media elements of the first type of media resource, the forward and backward selection buttons of the user interface will automatically invoke the exclusive forward or backward link 27 to transport the user to the base media element 24 of the second selected hypermedia resource or back to the base media element of the previous hypermedia resource. Assuming the common remote information node 16 received the command to move forward to the second hypermedia resource, the user again has the freedom to browse media elements starting with the base media element in the second hypermedia resource. Again, regardless of the media element presently being viewed in the second hypermedia resource, selecting the forward or back button in the user interface will only allow the user to move to the base element of the prior hypermedia resource or of any subsequent hypermedia resource in the order previously assigned in the linear hypermedia resource program. Different versions of a method for creating a linear hypermedia resource program are pictorially illustrated in FIGS. 14 and 15. FIG. 14 illustrates the ability to select any one of a number of media elements from desired media resources and add the selected media elements to a linear hypermedia resource program. A first media element may be selected from a hypermedia resource and then a user may use a hyperlink to jump to a second hypermedia resource, select a media element from the second hypermedia resource, and then the user may decide to implement a search engine to search the Web and jump to an unrelated third hypermedia resource. At the third hypermedia resource, the user can select any of the media elements to add to the linear hypermedia resource program. Alternatively, as shown in FIG. 15, the user may elect to add every media element, in the sequence encountered while browsing, to a linear hypermedia resource program. The various methods described herein, in a preferred embodiment, are intended for operation as software programs running on a computer processor. One of ordinary skill in the art will recognize that other hardware implementations such as application specific integrated circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. It should also be noted that the various methods of the present invention can be implemented in software, in one of a variety of known computer languages, and stored on a tangible storage medium such as a magnetic or optical disk, read-only memory or random access memory and be produced as an article of manufacture. As has been described above, a system and method for navigating and creating linear hypermedia resource programs are provided. The system and method provide a serial entertainment medium for internet Web users of all experience levels. A common remote information node such as a server operated by an internet service provider may generate, and store the contents of, a linear hypermedia resource program. A user can access the program through a user interface from a subscriber terminal. The program, which may consist of Web pages from one or more websites, is preferably traversed linearly with the user interface. Depending on a selected skill level, various links may be disabled to better guide a user along the predetermined linear path. The method also describes selecting media elements to include and editing their placement in the linear program. As will be recognized by those skilled in the art, the type of computers and communications devices used may be any one of a number of commonly available computers and communications devices. The communications networks for interconnecting hypermedia resources in the distributed hypermedia resource network may be internet communications networks or other types of networks. It is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that the following claims, including all equivalents, are intended to define the scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>The World Wide Web (the “Web”) provides an alternative source of information for consumers and business users. Some users also view the Web as a source of entertainment. Surfing the Web, cybercafes, etc. appeal to the sophisticated Web user as a way of having a good time. Many Americans raised in the television age view entertainment as a serial event. Specifically, generations of viewers have experienced television shows, movies, radio programs, and concerts which all proceed linearly from a beginning to an end. Some potential Web users of this generation view surfing the Web as intimidating from perhaps two respects: (1) the use of technology; and (2) the increasingly unorganized, virtually unlimited number of choices that are available. The Web is not inherently a linear entertainment medium. A Web user may typically go directly from any given site to a large number of other sites. At best, some websites provide links to similar sites, however they typically do not offer more than a cursory indication of what the linked sites contain. In addition, even sophisticated Web users are often frustrated by the amount of useless, undesirable material that appears on the Web. Take, for example, a user who wishes to look at pictures of classic automobiles. A search on classic automobiles may yield 10,000 hits. A website-by-website search for interesting material may yield many sites that do not meet the user's expectations as to the content, properties or quality. Some sites may be a single page that prompts a user to order a catalog. Other sites may have text but no pictures. Accordingly, there is a need for creating entertaining Web programs that appeal to a wide cross section of potential viewers.
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<SOH> BRIEF DESCRIPTION OF THE DRAWINGS <EOH>FIG. 1 is a diagram of a system for use in creating and navigating a linear hypermedia resource program according to a preferred embodiment. FIG. 2 illustrates hypermedia resources that may reside on information nodes in the distributed hypermedia network of FIG. 1 . FIG. 3 diagrammatically illustrates a linear hypermedia resource program and the selected base media elements in each of the desired hypermedia resources of the hypermedia resource data network. FIG. 4 illustrates a user interface for use in navigating a hypermedia resource program in accordance with one embodiment of the present invention. FIG. 5 is a flow diagram of a method for navigating a linear hypermedia resource program. FIG. 6 is a flow diagram illustrating an alternative method for navigating a linear hypermedia resource program in accordance with one embodiment of the present invention. FIG. 7 illustrates a user interface for prompting a user for an experience level in accordance with one embodiment of the present invention. FIG. 8 illustrates a method of generating a linear hypermedia resource program utilizing the system of FIG. 1 in accordance with one embodiment of the present invention. FIG. 9 illustrates an alternative embodiment of a method of generating linear hypermedia resource program. FIG. 10 is a flow diagram illustrating a third embodiment of a method for generating a linear hypermedia resource program. FIG. 11 is a flow diagram illustrating a fourth embodiment of a method for generating a linear hypermedia resource program. FIG. 12 is a flow diagram of a method for generating a linear hypermedia resource program in billing a user. FIG. 13 diagrammatically illustrates one preferred embodiment of navigating a linear hypermedia resource program. FIG. 14 diagrammatically illustrates one preferred embodiment of a method for creating a linear hypermedia resource program. FIG. 15 illustrates an alternative embodiment of a method for creating a linear hypermedia resource program. detailed-description description="Detailed Description" end="lead"?
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20040701
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20070508
|
20050512
|
82046.0
| 4
|
BAROT, BHARAT
|
SYSTEM AND METHOD FOR CREATING AND NAVIGATING A LINEAR HYPERMEDIA RESOURCE PROGRAM
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UNDISCOUNTED
| 1
|
CONT-ACCEPTED
| 2,004
|
|||
10,884,340
|
ACCEPTED
|
Air delivery apparatus and method
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An air compressor, air reservoir and an air dryer each are provided on wheeled frame. Compressed air charges the reservoir and is dehumidified in the dryer for simultaneous delivery to plural air ventilation systems worn by individuals.
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1. Air delivery apparatus for delivering air simultaneously to a plurality of individuals, each wearing an air ventilation garment for regulating or modifying the individual's body temperature, comprising: an air compressor; an air reservoir fluidly connected to the air compressor; an air dryer fluidly connected to the air reservoir; and an air distribution module fluidly connected to the air dryer and capable of simultaneously delivering air to a plurality of ventilation garments worn by individuals to regulate or modify body temperature. 2. The air delivery apparatus according to claim 1 wherein the air distribution module is further defined by a main air delivery hose connected to the air reservoir and plural branch hoses, each branch hose capable of connection to an individual using an air ventilation system. 3. (canceled) 4. The air delivery apparatus according to claim 2 having a pressure control valve in the main air delivery hose. 5. The air delivery apparatus according to claim 1 including an air refrigerator between the air dryer and the air distribution module. 6. The air delivery apparatus according to claim 1 including an air heater between the air dryer and the air distribution module. 7. The air delivery apparatus according to claim 1 including an air refrigerator and an air heater between the air dryer and the air distribution module. 8. The air delivery apparatus according to claim 1 wherein the air dryer is operable to dry air delivered to the air distribution module to a relative humidity of less than 50%. 9. The air delivery apparatus according to claim 1 wherein the air compressor is mechanically connected to the air reservoir and the air reservoir is mechanically connected to the air dryer. 10. The air delivery apparatus according to claim 1 wherein the air compressor is an electric rotary vane compressor. 11. The air delivery apparatus according to claim 1 wherein each air ventilation system is further defined by a garment worn by an individual, said garment comprising an air permeable fabric inner layer, an air impermeable fabric outer layer, and plural air channels defined between said inner and outer layers. 12. The air delivery apparatus according to claim 10 wherein said garment includes plural holes extending through the inner and outer layers. 13. The air delivery apparatus according to claim 12 wherein said garment includes a fitting for selective connection of the garment to the air distribution module. 14. The air delivery apparatus according to claim 13 wherein the individuals are athletes. 15. The air delivery apparatus according to claim 14 wherein the athletes are football players. 16. A method of delivering treated air simultaneously to a plurality of air ventilation garments, each garment configured to be worn by an individual and each garment configure to be used for regulating and modifying the individual's body temperature, comprising the steps of: a) providing a portable air compressor; b) providing a portable air reservoir; c) providing a portable air dryer; d) moving the air compressor, air reservoir and air dryer to a desired location; e) fluidly connecting the air dryer to the air compressor and fluidly connecting the air dryer to the air reservoir; f) fluidly connecting an air distribution module to the air dryer, the air distribution module having plural distribution lines; and g) selectively connecting distribution lines to air ventilation garments worn by individuals and simultaneously delivering desiccated air to each of the distribution lines connected to an air ventilation garment. 17. (canceled) 18. (canceled) 19. (canceled) 20. The method according to claim 16 including the step of operating the air dryer to dehumidify the delivered air to a relative humidity of less than about 30%. 21. The method according to claim 16 including mounting the air compressor, air reservoir and air dryer on respective wheeled frames. 22. An air delivery apparatus for delivering treated air simultaneously to plural body temperature regulating air ventilation apparatus, comprising: an air compressor; an air reservoir fluidly connected to the air compressor; an air desiccator fluidly connected to the air reservoir; an air distribution module fluidly connected to the air desiccator and having plural air distribution lines; and plural air ventilation garment means, each configured for being worn by an individual and each for cooling the body of the individual, and each air ventilation means selectively connectable to an air distribution line. 23. (canceled) 24. Apparatus according to claim 22 in which each air ventilation means further comprises a garment worn by an individual, said garment comprising an air permeable fabric inner layer, an air impermeable fabric outer layer, and plural air channels between said inner and outer layers. 25. Apparatus according to claim 24 wherein said garment includes plural holes extending through the inner and outer layers. 26. Apparatus according to claim 23 wherein each of the air compressor, air reservoir, and air dryer are separately mounted on a wheeled frame. 27. A method of simultaneously delivering treated air to plural users on the sidelines in order to regulate and modify the body temperature of the users, each of said users wearing an air ventilation system, comprising the steps of: a) locating a portable air compressor on the sidelines; b) locating a portable air reservoir on the sidelines: c) fluidly connecting the air reservoir to the air compressor; d) fluidly connecting an air distribution module having plural distribution lines to the air reservoir; e) operating the air compressor to deliver air to the air distribution module; f) connecting plural air distribution lines to plural air ventilation systems worn by plural users; and e) simultaneously delivering air to each of the plural distribution lines. 28. The method according to claim 27 including the step of treating the air so that it is delivered at a predetermined relative humidity. 29. The method according to claim 28 wherein the step of treating the air includes drying the air in an air dryer. 30. The method according to claim 27 including the step of cooling the air. 31. The method according to claim 27 including the step of heating the air. 32. The method according to claim 27 wherein the plural users comprise athletes. 33. The method according to claim 32 wherein the athletes are football players.
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FIELD OF THE INVENTION The present invention relates generally to air delivery systems, and more particularly to a modular air delivery system that provides a supply of pressurized, treated air to protective equipment worn by an individual to regulate the individual's body temperature. BACKGROUND Many people wear equipment and clothing designed to protect them from temperature extremes, and to regulate the temperature of their body. Professionals such as firefighters and athletes most often use this type of protective equipment and clothing, although use of such clothing is by no means limited to these users. For example, firefighters are required to wear heavy clothing that provides protection from extreme heat. While the heavy clothing worn by firefighters serves an important function by shielding the user from heat, it similarly is very warm and can lead to the wearer becoming overheated. Likewise, athletes such as football and hockey players, and racecar drivers wear heavy protective gear that provides essential protection, but which may lead to overheating. This is especially true with football players who often play in hot, humid conditions. Just as heavy protective clothing and equipment serves a necessary purpose, in doing so it can contribute to overheating, which in extreme cases may be a dangerous condition. Various ventilation systems worn by athletes and the like have been designed for alleviating overheating caused by protective clothing and equipment. For example, U.S. Pat. No. 4,738,119 to Zafred, U.S. Pat. No. 5,970,519 to Weber, and U.S. Pat. No. 6,596,019 to Turner et al. each describe ventilation systems that are worn by individuals who can benefit by keeping body temperature regulated. Each of the cooling apparel systems described in these patents requires a source of a fluid that may be supplied to the apparel system. In the '119 patent the apparel device is connected to a source of liquid carbon dioxide. The cooling garment is charged with liquid carbon dioxide, which converts to a solid phase in the garment, and the garment is then disconnected from the carbon dioxide source. The solid carbon dioxide in the garment sublimates while the garment is worn to thereby cool the user. The '519 patent provides a method for connecting the garment to a source of relatively dry air—the air flows through an air permeable layer in the garment to cool the wearer. Air may be supplied to the garment from a pressurized canister mounted to a wearer's belt, a remote supply such as a compressor, or a portable blower. The '019 patent describes a ventilation system having an air bladder that receives air from a compressor to supply warm or cooled air to the ventilation system. There is a need for improved air delivery systems designed for use with ventilation systems worn by individuals to regulate body temperature. BRIEF SUMMARY OF THE INVENTION The present invention provides a modular air delivery system for use in supplying treated air to plural individuals wearing ventilation apparatus. The system is modular and easily transported to any location. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and its numerous objects and advantages will be apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings. FIG. 1 is schematic view of a modular air delivery apparatus according to the present invention showing components of the apparatus and one environment in which the modular air delivery apparatus may be used. FIG. 2 is front view of a preferred embodiment of ventilation system, in this case a ventilation garment, with which the modular air delivery apparatus may be used. FIG. 3 is a rear view of the ventilation system shown in FIG. 2 with the outer layer of the garment removed to expose the underlying layer. FIG. 4 is a front view of the ventilation system shown in FIG. 3, with the outer layer of the garment removed to expose the underlying layer. FIG. 5 is a cross sectional view taken along the line 5-5 of FIG. 2. FIG. 6. is a plan view of a preferred embodiment of the inner layer of the ventilation system shown in FIG. 2, prior to the ventilation system being incorporated into a garment. FIG. 7. is a plan view of the ventilation system shown in FIG. 6, illustrating air channels. FIG. 8. is a plan view outer layer of the ventilation system shown in FIG. 2, prior to the ventilation system being incorporated into a garment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Where ventilations systems such as those described herein are used, there is often a need to supply air to more than one user of the system. For example, many members of a football team's offense may be wearing ventilation systems such as that described below with reference to FIGS. 2 through 8. Each individual player in this case needs to have a separate supply of air. The same is true of firefighters: there are instances where many individuals need to attach their ventilation system to a supply of cooling air. In addition, in many locations where ventilation systems are worn, there are a variety of restrictions in place on the types of equipment that are allowed. As just one example, many football stadiums place restrictions on the type and size of compressors that are allowed onto the sidelines—gas-powered compressors may not allowed, or if they are allowed, they must be remotely located from the place where the players need them. The same is true in ice arenas where hockey is played. The air delivery apparatus 10 described herein may be used to deliver treated air to any suitable ventilation system, and is capable of delivering treated air to plural users. One suitable ventilation system is described herein with reference to a ventilation garment. With reference now to FIG. 1, the air delivery apparatus 10 according to the present invention is shown as including several component parts, each of which is a contained in a separate wheeled module. Thus, apparatus 10 includes an air compressor 12, a first air reservoir 20, a second, optional air reservoir 22, a dryer 30, and a treated air distribution module referenced generally with number 40 that is configured to simultaneously deliver treated air to plural ventilation systems, each worn by a wearer such as 50a, 50b, 50c . . . through 50g. In the illustration of FIG. 1, wearers 50 are shown to be athletes such as football players seated on a player bench 52 such as would be found on the sidelines in a football stadium. From the description that follows it will be appreciated that the number of individual connections to wearers 50 that air delivery module 40 is designed to serve may be tailored according to need. In the case of a football team, the number of wearers could be 11 as shown in FIG. 1—the number of players on the offensive and defensive teams. The invention is not limited to use by football players or players in any other sport, or any number of wearers. Each of the components will now be separately described. Compressor 12, each air reservoir 20, 22, and air dryer 30 are modular units that are supplied on wheeled frames 60 that allow the units to be very portable and thus easily moved from place to place without the assistance of tractors and the like. The modular units may be quickly connected to and uncoupled from one another as shown in FIG. 1 with coupling arms 62, and the coupling arms may be used as handles to push and pull the units, as with coupling arm 62 on air dryer 30. The wheeled frames 60 allow the modular units to be moved individually or together as an interconnected group as in FIG. 1. The compressor, reservoirs and air dryer may be mounted onto wheeled frames in any appropriate manner that allows the frames and the equipment mounted on them to be easily moved from location to location. While the wheeled frames make transporting the individual modular units from place to place, the modular units may be provided without wheels so long as the units are portable. Turning now to a description of the individual modules, air compressor 12 is an electric compressor that preferably is operable on a 110V power supply, although a compressor operable on a 220V or other power supply will suffice. The preferred compressor 12 is a rotary vane type of compressor. Such compressors are available from numerous commercial suppliers. The air compressor 12 selected for use in any particular air delivery apparatus 10 should be of an appropriate size for that particular apparatus, and should have sufficient operating capacity to pressurize and maintain each air reservoir used in the apparatus. Although not shown in the drawings, air compressor 12 includes appropriate control mechanisms and operations indicators such as output air pressure and the like. Any number of air reservoirs such as first air reservoir 20 and second air reservoir 22 may be used in series as shown in FIG. 1, and the air compressor 12 should be of sufficient size to charge each air reservoir to the desired operating pressure. In the preferred embodiment the air reservoirs 20 and 22 are pressurized to an operating pressure of about 100 lb/in2 or above. Increasing the number of reservoirs 20 in an air delivery apparatus 10 increases the output capacity of the system. The air compressor 12 is connected to the first air reservoir 20 with a flexible high-pressure hose 24 that preferably is fitted with a quick-connect type of coupler 26 that allows the hose to be quickly connected to and disconnected from the air reservoir. Although a coupler 26 is shown on only the downstream end of high-pressure hose 24, each end of the hose may be fitted with a like coupler. Preferably, each high-pressure hose used in apparatus 10 will be insulated to minimize any change in air temperature resulting from environmental exposure. Moreover, the length of hosing is preferably minimized to reduce fluctuation in air temperature between modular units such as air compressor 12, and air reservoir 20. Each air reservoir 20, 22 preferably includes an air pressure gauge 21 and other appropriate control apparatus such as air pressure regulation valves and the like. Each successive air reservoir is likewise coupled to the previous reservoir with a high-pressure hose fitted with quick-connect couplers. Thus, second air reservoir 22 is connected to first air reservoir 20 with high-pressure hose 28 equipped with coupler 26. Air dryer 30 is a compressed air dryer having a capacity matched to the capacity of the rest of apparatus 10, and preferably is of the type having an easily replaceable, modular desiccant cartridge. The compressed air dryer 30 dries the air to a relative humidity at the outlet of the dryer that is appropriate under the conditions, considering for example the relative humidity and temperature of the ambient air, the purpose for which the air is being used, etc. In a typical example of use of apparatus 10 with a football team in typical weather conditions, air dryer 30 preferably dries the air to a relative humidity at the outlet of the dryer of to a humidity in the range of between about 50% to less than 1%. It will be appreciated that the relative humidity of air leaving the dryer may vary significantly. As with the high-pressure hoses that interconnect the first and second air reservoirs, compressed air dryer 30 is coupled to second air reservoir 22 with a flexible high-pressure hose, preferably including quick connect couplers 26. Compressed air dryer 30 preferably is equipped with monitoring and control systems such as a relative humidity meter 31 that provides information about the moisture content of output air. Although not shown in the drawings, an output air pressure regulating valve may optionally be used on the output fitting from air dryer 30. In some instances the air dryer 30 may be omitted—for example, in locations where the ambient air is at a low relative humidity. Desiccated air is output from compressed air dryer 30 to air delivery module 40, which includes a flexible, insulated high-pressure main air hose 42 that may optionally include an in-line pressure control valve 44 operable to increase and or decrease air pressure in main air hose 42 according to need. Main air hose 42 terminates in a T-fitting 46 that supplies first branch hose 48 and second branch hose 49. Each branch hose 48, 49 is fitted with plural T-fittings 51, each of which is connected to an air connection hose 54 that is used to couple the air delivery module 40 to individual wearers 50. In FIG. 1, seven individual wearers 50 are shown having their air ventilation apparel systems connected to one of the air connection hoses 54. Each air connection hose 54 has a quick connect coupler 56 on its terminal end. Quick connect couplers 56 are connectable to the input fittings on the air ventilation apparel and are one-way valve fittings that are open when a connection to an air ventilation garment is made, and closed when the connection to the garment is disconnected. Because the air delivery apparatus 10 described above is comprised of modular units that may be quickly and easily interconnected, the entire apparatus 10 may be delivered to locations where it is needed very quickly. Because the air compressor 12 is powered by electricity, there are few restrictions on transporting the unit on most carriers such as airlines, which often restrict transportation of equipment powered with fossil fuels. The individual components of apparatus 10 may thus be transported to any location, wheeled to a specific location where wearers 50 are located (either before or after the individual modules 12, 22, etc. are connected to one another), and operated. Turning now to FIGS. 2 through 8, one preferred ventilation system 100 with which the air delivery apparatus 10 described above may be used is described. Although the ventilation system 100 described herein and shown in FIGS. 2 through 4 is embodied in a garment such as a T-shirt 150, it is to be understood that the ventilation system may also be incorporated with or in other items such as, for example, football helmets, firefighter's headgear, pants, jackets, sports equipment, shoes, gloves, blankets, and any other item that may be used by an individual to modify or regulate the individual's body temperature. With reference to FIGS. 6 through 8, a ventilation system that is designed for incorporation into a T-shirt (as shown in FIGS. 2 through 4) includes an inner layer 110 (FIG. 6), an outer layer 130 (FIG. 8) and an intermediate layer 120 (FIG. 7). Inner layer 110 is preferably a fabric material having microporous structure that has holes of a size that allows air to diffuse through the layer. Outer layer 130 is preferably a fabric material that is impermeable to air, such as fabric coated with a plastic material. The three layers 110, 120 and 130 are sandwiched together atop one another such that the intermediate layer 120 defines a series of air channels 122. The air channels 122 are operatively connected through an air hose 140 to a source of air, such as the air delivery apparatus 10 described herein. It will be appreciated that intermediate layer 120 and the air channels 122 defined in ventilation system 100 may be formed with glue applied between the inner and outer layers 110 and 130, or may be formed by welding the inner and outer layers, 110 and 130, together, such as with radio frequency welding. As such, intermediate layer 120 need not be a distinct layer, but instead is the joined interface area between the inner and outer layers, 110 and 130, that define the air channels through the ventilation system. As noted above, the ventilation system is typically incorporated into a garment such as the T-shirt 150 shown in FIGS. 2 through 4. The portion in which the intermediate layer 120 comprises glue or welded areas is shown in the drawings with stippling and is identified in FIG. 7 with reference number 124. The arrows 112 in the drawings illustrate the flow of air through ventilation system 100. Air is introduced to ventilation system 100 through air hose 140 and flows through channels 122. When the ventilation system is incorporated into a T-shirt 150, the air channels 122 extend over the front and back portions of the garment so that air flows over the user's back, shoulders and chest. Referring to FIG. 5, air flowing through channel 122 diffuses through inner layer 120, which as noted is permeable to air, toward the wearer's body. Outer layer 130 is not air-permeable, so air flows in a one-way direction through inner layer 110, toward the wearer's body. Because outer layer 130 is not permeable, a series of through holes 160 are formed through the ventilation system 100 in the glued areas 124 to allow sweat to escape from the wearer's body to the atmosphere. In operation, each of the individual modular units in apparatus 10 is positioned as desired and interconnected to one another as shown in FIG. 1. Air compressor 12 is connected to an appropriate power source and each air reservoir 20, 22 is charged to a predetermined operating pressure. The operating pressure is adjusted with pressure regulation control valves. Pressure control valve 44, if used, is adjusted to the desired output pressure according to the working pressure that is most suited to the type of air ventilation garment that the wearers are using. The air dryer 30 is adjusted so that the air delivered to users is desiccated relative to atmospheric air, and as noted, the relative humidity of the air delivered to users is about 30% or less. The wearers may then connect their ventilation garments such as ventilation a systems 100 to air delivery hoses with quick connect couplers 56 as desired. Once a connection is made, air having desired moisture content and pressure is delivered to the ventilation garment. It will be appreciated that compressed air is normally cooler than ambient air temperatures. As such, air delivery apparatus 10 need not include refrigeration systems to deliver air that is relatively cooler than ambient air. Moreover, because the air delivered from air delivery apparatus 10 to the wearers 50 has a relative humidity that is lower than that of the atmosphere, evaporative drying and the cooling effect of it is increased. Nonetheless, air delivery apparatus 10 may optionally include an air refrigerator 70 inline in the system, shown schematically in FIG. 1 in main air hose 42. Likewise, air delivery apparatus 10 may optionally be used to deliver heated air to wearers 50 by use of an air heater 72, also shown schematically inline in main air hose 42. Where an air refrigerator 70 and/or an air heater 72 are used, the equipment is provided on a wheeled frame with quick connect couplings. As noted above, because each of the modular units that are used in air delivery apparatus 10 are separately contained on wheeled frames (i.e., air compressor 12, air reservoir 20, air dryer 30), the entire system may be quickly transported to the precise location where it is needed. For example, in the case where athletes such as football players are wearing the ventilation systems 100, the air delivery apparatus 10 may be set up next to the players' bench. Hockey teams may similarly set the system up next to the bench. As used herein, the term “sidelines” thus refers to a location adjacent a sporting field such as a football field, hockey rink, etc. As noted above, the air delivery apparatus 10 may be used to deliver treated air to firefighters and the like, as well. The term sidelines thus by analogy refers to the locations where the air delivery apparatus may be used to deliver treated air to any user. With American football players, some or all of the offensive team members may be connected to the air delivery apparatus on the sideline while the defensive team is on the field, and vice versa. While the present invention has been described in terms of a preferred embodiment, it will be appreciated by one of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims.
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<SOH> BACKGROUND <EOH>Many people wear equipment and clothing designed to protect them from temperature extremes, and to regulate the temperature of their body. Professionals such as firefighters and athletes most often use this type of protective equipment and clothing, although use of such clothing is by no means limited to these users. For example, firefighters are required to wear heavy clothing that provides protection from extreme heat. While the heavy clothing worn by firefighters serves an important function by shielding the user from heat, it similarly is very warm and can lead to the wearer becoming overheated. Likewise, athletes such as football and hockey players, and racecar drivers wear heavy protective gear that provides essential protection, but which may lead to overheating. This is especially true with football players who often play in hot, humid conditions. Just as heavy protective clothing and equipment serves a necessary purpose, in doing so it can contribute to overheating, which in extreme cases may be a dangerous condition. Various ventilation systems worn by athletes and the like have been designed for alleviating overheating caused by protective clothing and equipment. For example, U.S. Pat. No. 4,738,119 to Zafred, U.S. Pat. No. 5,970,519 to Weber, and U.S. Pat. No. 6,596,019 to Turner et al. each describe ventilation systems that are worn by individuals who can benefit by keeping body temperature regulated. Each of the cooling apparel systems described in these patents requires a source of a fluid that may be supplied to the apparel system. In the '119 patent the apparel device is connected to a source of liquid carbon dioxide. The cooling garment is charged with liquid carbon dioxide, which converts to a solid phase in the garment, and the garment is then disconnected from the carbon dioxide source. The solid carbon dioxide in the garment sublimates while the garment is worn to thereby cool the user. The '519 patent provides a method for connecting the garment to a source of relatively dry air—the air flows through an air permeable layer in the garment to cool the wearer. Air may be supplied to the garment from a pressurized canister mounted to a wearer's belt, a remote supply such as a compressor, or a portable blower. The '019 patent describes a ventilation system having an air bladder that receives air from a compressor to supply warm or cooled air to the ventilation system. There is a need for improved air delivery systems designed for use with ventilation systems worn by individuals to regulate body temperature.
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<SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The present invention provides a modular air delivery system for use in supplying treated air to plural individuals wearing ventilation apparatus. The system is modular and easily transported to any location.
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20040701
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20131210
|
20060105
|
59055.0
|
B08B1500
| 0
|
KOSANOVIC, HELENA
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Air delivery apparatus and method
|
UNDISCOUNTED
| 0
|
ACCEPTED
|
B08B
| 2,004
|
|
10,884,354
|
ACCEPTED
|
Dryer venting apparatus, techniques and installation kit
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Venting through the walls of an interior room of a building to an external environment is facilitated by apparatus and techniques for mounting an in-wall unit for interfacing with the exhaust ports of equipment, such as dryers, using flexible pipe. The in-wall unit connects with venting pipe, such as stovepipe, for connecting to the external environment through an exterior surface, such as a roof. If a roof exhaust is desired, a vent assembly is provided that contains a flap that automatically closes when the exhaust flow terminates, but opens when venting is underway. The flap is removable so that cleanout of path between the in-wall unit and the room exhaust can easily occur.
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1. An in-wall unit for providing an interface between equipment needing venting and an exterior environment, comprising: a. a base plate; b. a hollow conical section Pac attached to said base plate and configured to receive flexible pipe from said equipment at a larger end and to connect to a path to said exterior environment at the smaller end; and c. at least one bracket for connecting to wall studs for supporting said base plate. 2. The in-wall unit of claim 1, in which said conical section is welded to said base plate. 3. The in-wall unit of claim 1, in which said conical section is attached to said base plate using solder. 4. The in-wall unit of claim 1, in which there are two brackets and the brackets are connected to wall studs for mounting said base plate. 5. The in-wall unit of claim 4, in which said base plate is screwed to said brackets. 6. The in-wall unit of claim 4, in which said base plate is taped to said brackets using metallized tape. 7. The in-wall unit of claim 1, in which flexible pipe is extended into said larger end of said conical section and is taped to said conical section using metallized tape. 8. The in-wall unit of claim 1, in which in which said equipment is connected to said flexible pipe. 9. The in-wall unit of claim 1, in which said conical unit is connected to a vent pipe which forms said path to said exterior environment. 10. The in-wall unit of claim 1, in which said vent pipe is connected to a roof vent unit. 11. The unit of claim 10, in which said roof vent unit comprises a flashing plate having an opening through which said stove pipe may pass, connected to a body for receiving a vent pipe through said opening in said flashing plate. 12. The unit of claim 11, in which said body accommodates a vent flap that provides ventilation to the exterior environment when air is exhausted through the vent pipe, but shuts when no air is forced against the vent flap this prevents back draft. 13. The unit of claim 11, in which the vent flap may be removed to provide clean-out access to the vent pipe and in-wall assembly. 14. The unit of claim 13 in which the vent flap is held in place by a removable roof vent unit cover. 15. A kit for installation of in-wall venting for equipment, comprising: a. a base plate; b. a hollow conical attached to the base plate; c. flexible pipe for said connecting said equipment to said conical section; d. at least one bracket for connecting to wall studs for supporting said base plate; and e. metallized tape for connecting said base plate to said flexible pipe. 16. A method of installing an in-wall unit for connecting equipment to an exhaust path, comprising the steps of: a. securing at least one mounting brackets to opposing studs of an interior wall; b. attaching a hollow conical section to an opening in a base plate; and c. securing said base plate to said mounting brackets. 17. The method of claim 16 in which the steps of connecting said conical section to said base plate is done by welding. 18. The method of claim 16 in which the steps of connecting said base plate to said mounting brackets is done by one of screwing or by taping with metallized tape. 19. The method of claim 16 in which the steps of securing said mounting brackets to said opposing studs is done by one of nailing or screwing said mounting brackets to said studs.
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CROSS REFERENCE TO RELATED APPLICATIONS This application incorporates by reference in its entirety and claims priority to U.S. Provisional Application 60/484,866, filed Jul. 3, 2003, by inventor Philip Charron. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is directed to equipment venting apparatus and techniques and to an installation kit for installing equipment venting, and particularly in-wall dryer venting. 2. Description of Related Art Technique for venting automatic clothes dryers through a wall to the external environment are well known in the art. However, use of this technique often requires that a laundry room abut against an external wall. This constrains the design of the home or building in which the dryer is to be placed and, when a laundry room is located internally, that is, does not abut an external wall, a problem arises because one cannot vent a dryer through the adjacent wall to the outside environment. In such circumstances, dryer venting may occur vertically within a wall and vent through a roof to the outside environment. BRIEF SUMMARY OF THE INVENTION The purpose of this invention is to provide for easy installation of dryer venting which is particularly suitable for installation in laundry rooms that are internal to a structure. The following figures and descriptions describe how this may be done and illustrate the techniques and components which can be utilized for such installation. In one aspect of the invention the components for such venting may be assembled into a kit. Although the best mode known to the inventor is set forth herein, it should be apparent that the invention is not limited to the particular embodiments shown. BRIEF DESCRIPTION OF THE DRAWINGS The invention is described more particularly hereinafter with reference to the accompanying drawings, in which: FIG. 1 is an exploded view of an in-wall unit in accordance with one aspect of the invention; FIGS. 2A and 2B represent a top and side view of a cone shown in FIG. 1. FIGS. 3A, 3B and 3C are respective top, side and end views of an in-wall unit base shown in FIG. 1. FIGS. 4A, 4B and 4C are respective top, side and end views on an assembled in-wall unit. FIGS. 5A, 5B and 5C are respective top, side and end views of mounting bracket shown in FIG. 1. FIG. 6 is an exploded view of a roof vent unit in accordance with one aspect of the invention. FIG. 7 shows an assembled roof vent unit. FIGS. 8A and 8B show respective top and side views of a roof vent body in accordance with one aspect of the invention. FIG. 9 shows a roof vent flashing plate in accordance with one aspect of the invention. FIG. 10 shows a roof vent exhaust plate in accordance with one aspect of the invention. FIG. 11 shows a roof vent exhaust flap in accordance with one aspect of the invention. FIG. 12 shows a roof vent top cover plate in accordance with one aspect of the invention. DETAILED DESCRIPTION OF THE INVENTION Automatic clothes dryers typically contain a heating unit and a rotating drum which tumbles wet clothing in such a way as to expose it to heated air in order to facilitate drying. The heated air represents a particular fire hazard if it were to be vented into a room of the home or other building in which the dryer is located. Other equipment besides dryers may require venting to the external environment. Typically, at the back of an automatic dryer is an exhaust vent, typically a round exhaust pipe to which a flexible venting pipe from the dryer may connect to an external vent. Typically, in the prior art, such external vents were placed through holes in exterior walls to allow the heated air to vent to the external environment. However, when a laundry room is to be located internal to a building structure in such a way as to not have access to an exterior wall, then other forms of venting must be utilized. In accordance with the invention, venting of automatic dryers may occur through an interior wall to an external surface, such as a roof. The invention provides a particularly convenient and safe technique for the venting of dryers through an internal wall. FIG. 1 of the drawing shows an exploded view of an in-wall unit in accordance with one aspect of the invention. A cone shaped unit 100 is attached to of an in-wall unit base 110 and serves to connect at its upper end to, for example, stove pipe which then forms an exhaust channel from the top of the cone shaped pipe to the roof or other external vent. The flared bottom end of the cone 100 received the flexible venting pipe from the dryer as described more hereinafter. Studs in typical interior walls of a building tend to be formed by two by fours. However, in this case, since the venting diameter may be larger, two by six studs may be utilized for mounting the in-wall unit shown in FIG. 1. To mount the in-wall unit, in the embodiment shown, two mounting brackets 120 are mounted opposite each other on adjacent two by six studs, approximately thirty inches above the floor. The sides of the mounting brackets having two holes are aligned with a horizontal line previously drawn on the two by six stud using a level. The mounting brackets are then secured to the two by six stud using, preferably, two wood screws. The other mounting bracket is then attached in similar fashion so that the two mounting brackets 120 form a surface upon which the mounting plate 110 can rest. In one implementation, the side of the mounting bracket has a single hole is drilled out, preferably, to receive a number 12 self tapping screw so that the base plate 110 can be secured to the top of the mounting brackets 120. Thus situated, the end wall unit is ready for connection to vent pipe, such as stovepipe, in the upper direction and for connection to the flexible pipe coming from the back of the equipment to the larger end. FIGS. 2A and 2B represent a top and side view of the cone shown in FIG. 1. The dimensions are given for an embodiment in which the base of the cone substantially matches the diameter if the hole in the base plate 1 10. In this configuration, the cone is tack welded three times to the base unit 110 and the seam can be sealed with silicone rubber. Similarly, the seam formed along the rivet line shown in FIG. 2B for the cone element 100 can be sealed with silicone rubber seal. Alternative ways for connecting the cone shaped element with the base plate will be discussed more hereinafter. FIGS. 3A, 3B and 3C are respective top, side and end views of an in-wall unit base shown in FIG. 1. The tabs extending down in FIG. 3B from the bottom of the in-wall unit base are used as follows. The flexible pipe from the dryer can be inserted through the hole in the base plate and forced to fit tight against the inside of cone 100 at the point of interference. The flexible pipe from the dryer is then held in place by metallized or metallic tape which connects the flexible pipe to the tabs shown in FIG. 3B, thus holding flexible pipe in position within the cone. FIGS. 4A, 4B and 4C are respective top, side and end views of an assembled in-wall unit. This unit has not been mounted to the mounting brackets 120. As noted above, the seam between the base plate and the bottom of the cone can be sealed with a silicone rubber seal and the tack welds, hold the conical sections securely in place. FIGS. 5A, 5B and 5C are respective top, side and end views of the mounting brackets 120. Although this figure gives preferred dimensions, the use of the mounting brackets has been described previously. FIG. 6 is an exploded view of a roof vent unit in accordance with one aspect of the invention. The stovepipe connected to the in-wall unit may extend through the roof of the building or may turn 90-degrees and be routed to an exterior wall where it can be vented using prior art techniques. In the event that the stovepipe is to be vented through the roof, the roof vent unit shown in FIG. 6 and FIG. 7 provides preferred way of venting the dryer exhaust to the external environment. As shown in FIGS. 6 and 7 a roof vent body 600, is firmly attached to a roof vent flashing plate 610 and to an exhaust plate 620. An exhaust flap 630 has two tabs which extend beyond the outer extent of the body of the flap and are utilized to mount in recesses in the body 600 in such a way that the flap may open freely when air pressure from the exhaust vent is applied to its under surface. The exhaust flap 630 is held in place by a top cover plate 640 which can be removed in order to permit access to the stovepipe for clean out purposes. FIG. 7 shows the assembled roof vent unit. FIGS. 8A and 8B show respective top and side views of a roof vent body in accordance with one aspect of the invention. Note the two notches having a radius of 0.130-inches at the top of the body adjacent the bend line. FIG. 9 shows a roof vent flashing plate in accordance with one aspect of the invention. The flashing plate forms the base of the roof vent unit. The body 600 is attached to the flashing plate, preferably by soldering in a continuous seam around the contact points between the bottom of the body 600 and the flashing plates 610. The alignment of the radius of the hole in the flashing plate and the radius of the curved portion of the body substantially coincide. FIG. 10 shows a roof vent exhaust plate in accordance with one aspect of the invention. The roof vent flashing plate 620 attaches just behind the 0.130 radius notches found in the body 600. It is mounted to permit the tabs on the exhaust flap 630 to rest in the notches without interference. The exhaust plate is tack soldered along a slope up from the flashing plate and continuously soldered along the bottom connection to the flashing plate. FIG. 11 shows a roof vent exhaust flap in accordance with one aspect of the invention. The 0.125 inch tabs at the top of the exhaust flap are placed in the 0.130-inch diameter notches in the top of the roof vent body 600. They sit there freely in such a way as to allow the roof vent flap to open when air from the exhaust of the dryer is applied against its surface. The roof vent exhaust flap 630 is held in place by attaching the top cover plate 640 to the body. FIG. 12 shows a roof vent top cover plate in accordance with one aspect of the invention. The roof vent cover plate is designed to be removable to permit the exhaust path to be cleaned out for servicing. The top cover plate is removed, the exhaust flap is removed and the openings are such that a flue brush can be inserted down into the stovepipe to permit cleanout of the exhaust pathway. Some alternative configurations exist. First, in less durable installations, the in-wall unit base plate may be secured with tape to the mounting brackets 120, rather than using the self-tapping screw. Further, in another embodiment, the conical section can be built with a larger diameter so that it extends only partially through the opening in the in-wall base plate 110. It can then be held in place using tape and the tabs on the base plate 110. In this arrangement, it may be desirable to have additional tabs at the large end of the conical section 100 to permit the taping of the flexible pipe coming from the dryer unit. The shortest straightest route is best when routing stove pipe to the desired termination point. In some jurisdictions, code requires a maximum of 25 feet from dryer determination point. Each 90-degree tern may subtract 5 feet and each 45-degree turn may subtract 2½ feet. Once the in-wall unit is installed, the wall can be finished with drywall and paint. The invention described herein is not limited to the specific examples shown, but rather has a broad applicability to communications generally.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The invention is directed to equipment venting apparatus and techniques and to an installation kit for installing equipment venting, and particularly in-wall dryer venting. 2. Description of Related Art Technique for venting automatic clothes dryers through a wall to the external environment are well known in the art. However, use of this technique often requires that a laundry room abut against an external wall. This constrains the design of the home or building in which the dryer is to be placed and, when a laundry room is located internally, that is, does not abut an external wall, a problem arises because one cannot vent a dryer through the adjacent wall to the outside environment. In such circumstances, dryer venting may occur vertically within a wall and vent through a roof to the outside environment.
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<SOH> BRIEF SUMMARY OF THE INVENTION <EOH>The purpose of this invention is to provide for easy installation of dryer venting which is particularly suitable for installation in laundry rooms that are internal to a structure. The following figures and descriptions describe how this may be done and illustrate the techniques and components which can be utilized for such installation. In one aspect of the invention the components for such venting may be assembled into a kit. Although the best mode known to the inventor is set forth herein, it should be apparent that the invention is not limited to the particular embodiments shown.
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20040702
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20080909
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20050113
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58971.0
| 0
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GRAVINI, STEPHEN MICHAEL
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DRYER VENTING APPARATUS, TECHNIQUES AND INSTALLATION KIT
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SMALL
| 0
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ACCEPTED
| 2,004
|
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10,884,524
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ACCEPTED
|
Use of volume Bragg gratings for the conditioning of laser emission characteristics
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Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.
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1. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light. 2. Apparatus according to claim 1, wherein conditioning the characteristics of the input light includes conditioning at least one of the spectral, spatial, and temporal characteristics of a light-emitting device. 3. Apparatus according to claim 1, wherein the VBG element is an extra-cavity VBG element that is external to the light-emitting device. 4. Apparatus according to claim 3, wherein the extra-cavity VBG element provides an external feedback to the light-emitting device. 5. Apparatus according to claim 3, wherein the light-emitting device is a laser adapted to operate above threshold in the absence of the external feedback. 6. Apparatus according to claim 1, wherein the VBG element is an intra-cavity VBG element disposed within a cavity of the light-emitting device. 7. Apparatus according to claim 6, wherein the intra-cavity VBG element is configured in a non-folding configuration. 8. Apparatus according to claim 7, wherein the VBG element is a transmissive VBG element. 9. Apparatus according to claim 7, wherein the VBG element has an axial symmetry with respect to an optical axis of a laser cavity of the light emitting device. 10. Apparatus according to claim 6, wherein the VBG element is adapted for use as an output coupler or high reflector of the light emitting device. 11. Apparatus according to claim 10, wherein the VBG element is a reflective VBG element. 12. Apparatus according to claim 11, wherein the VBG element has a clear aperture, and a reflectivity that varies smoothly as a function of position within the clear aperture. 13. Apparatus according to claim 12, comprising a soft-aperture VBG reflector. 14. Apparatus according to claim 1, wherein the VBG element has recorded thereon at least one of a holographic image, grating, or other structure that conditions the one or more characteristics of the input light. 15. Apparatus according to claim 1, wherein the input light is laser light. 16. Apparatus according to claim 1, wherein the light-emitting device is one of a solid-state laser, a semiconductor laser diode, a semiconductor super-luminescent laser diode, a solid-state light-emitting diode, a gas laser, and an ion laser. 17. Apparatus according to claim 1, wherein the VBG redirects at least a portion of the input light. 18. Apparatus according to claim 1, further comprising a reflector that redirects at least a portion of the light conditioned by the VBG. 19. Apparatus according to claim 18, wherein the reflector is integrated into the VBG. 20. Apparatus according to claim 1, wherein an optical power density incident upon an area of the VBG element is at least about 40 W/cm2. 21. Apparatus according to claim 1, wherein a total optical power incident upon a clear aperture of the VBG element is at least about 20 W. 22. Apparatus comprising: a single-emitter broad-area multiple transverse mode laser diode device; and a volume Bragg grating (VBG) element that receives input light generated by the laser diode device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light. 23. Apparatus according to claim 22, wherein conditioning the characteristics of the input light includes conditioning at least one of the spectral, spatial, and temporal characteristics of a laser diode device. 24. Apparatus according to claim 23, wherein the VBG element is an extra-cavity VBG element that provides an external feedback to the laser diode device. 25. Apparatus according to claim 23, wherein the VBG element is an intra-cavity VBG element disposed within a cavity of the light-emitting device. 26. Apparatus comprising: an array of broad-area multiple transverse mode laser diode devices; and one or more volume Bragg grating (VBG) elements that receives input light generated by the array of laser diode devices, conditions one or more characteristics of the input light, and causes the laser diode devices to generate light having the one or more characteristics of the conditioned light. 27. Apparatus according to claim 26, further comprising a wavelength multiplexer, wherein the input light generated by the array of laser diode devices is simultaneously combined and conditioned via a feedback passing through the wavelength multiplexer. 28. Apparatus according to claim 27, wherein the wavelength multiplexer is an intra-cavity wavelength multiplexer. 29. Apparatus according to claim 27, wherein the wavelength multiplexer is an extra-cavity wavelength multiplexer. 30. Apparatus according to claim 27, wherein the wavelength multiplexer is constructed from one or more VBG elements. 31. Apparatus according to claim 26, wherein at least one of the VBG elements is an extra-cavity VBG element that provides a feedback to at least one of the laser diode devices. 32. Apparatus according to claim 26, wherein at least one of the VBG elements is an intra-cavity VBG element that provides a feedback to at least one of the laser diode devices. 33. Apparatus according to claim 26, wherein at least one of the laser diode devices has an emitting aperture of at least 50 μm. 34. Apparatus according to claim 31, wherein at least one of the laser diode devices is adapted to operate above threshold in the absence of the feedback. 35. Apparatus according to claim 32, wherein at least one of the laser diode devices is adapted to operate above threshold in the absence of the feedback. 36. Apparatus according to claim 31, wherein at least one of the laser diode devices is adapted to operate below threshold in the absence of the feedback. 37. Apparatus according to claim 32, wherein at least one of the laser diode devices is adapted to operate below threshold in the absence of the feedback. 38. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a light emitting device; a cylindrical microlens that receives input light generated by the light-emitting device; and a volume Bragg grating (VBG) element that receives redirected light from the microlens, conditions one or more characteristics of the redirected light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light. 39. Apparatus according to claim 38, wherein the microlens collimates the input light along a fast axis of the light emitting device. 40. Apparatus according to claim 38, wherein the microlens reduces divergence of the input light along a fast axis of the light emitting device. 41. Apparatus according to claim 38, wherein the VBG element provides external feedback to the light emitting device. 42. Apparatus according to claim 38, wherein the lens has a focal length in the range of about 0.05 mm to about 3.0 mm. 43. Apparatus according to claim 38, wherein the VBG element has a thickness in a range from about 0.2 mm to about 3.0 mm, and a reflectivity in a range from about 5 percent to about 60 percent. 44. Apparatus according to claim 38, wherein the VBG element is positioned at distance behind the microlens, the distance being in a range from about 0 mm to about 10 mm. 45. Apparatus according to claim 38, wherein the microlens is formed on or attached to a surface of the VBG element. 46. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a light emitting device; and a volume Bragg grating (VBG) element that receives input light from the light emitting device, conditions one or more characteristics of the redirected light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light, wherein the VBG element receives the input light from the light emitting device in the absence of optics between the light emitting device and the VBG element that collimates or reduces the divergence along either a fast axis or a slow axis of the light emitting device. 47. Apparatus according to claim 46, wherein the VBG element has a thickness in the range of about 0.2 mm to about 3.0 mm. 48. Apparatus according to claim 46, wherein the VBG element is positioned at distance in front of the laser, the distance being in a range from about 0 mm to about 5 mm. 49. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a light emitting device; and a volume Bragg grating (VBG) element that receives input light from the light emitting device, conditions one or more characteristics of the redirected light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light, =p1 wherein the VBG element has a clear aperture and a period and peak wavelength that vary smoothly as a function of position within the clear aperture. 50. Apparatus according to claim 49, wherein the VBG element is an extra-cavity reflective VBG element that provides an external feedback to the light-emitting device. 51. Apparatus according to claim 49, wherein the VBG element is an intra-cavity reflective VBG element disposed within a cavity of the light-emitting device. 52. Apparatus according to claim 49, comprising a transverse chirp VBG reflector. 53. Apparatus for altering a characteristic of a light-emitting device, the apparatus comprising: a light emitting device; and a volume Bragg grating (VBG) element that receives input light from the light emitting device, conditions one or more characteristics of the redirected light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light, wherein the VBG element has a period and peak wavelength that vary smoothly as a function of position along a direction of propagation of the input light. 54. Apparatus according to claim 53, wherein the VBG element is an extra-cavity reflective VBG element that provides an external feedback to the light-emitting device. 55. Apparatus according to claim 53, wherein the VBG element is an intra-cavity reflective VBG element disposed within a cavity of the light-emitting device. 56. Apparatus according to claim 53, comprising a longitudinal chirp VBG reflector. 57. A volume Bragg grating (“VBG”) element comprising a photorefractive material having a holographic grating recorded thereon, said holographic grating having a grating period that varies as a function of position along an axis of the VBG element. 58. The VBG element of claim 57, wherein the VBG element has a longitudinal axis along which light received by the VBG is transmitted through the VBG element, and wherein the grating period varies as a function of position along the longitudinal axis. 59. The VBG element of claim 57, wherein the VBG element has a longitudinal axis along which light received by the VBG is transmitted through the VBG element, and wherein the grating period varies as a function of position along an axis that is transverse to the longitudinal axis. 60. A solid-state laser having a laser cavity and comprising a reflective VBG element receives input radiation from the laser, reflects at least a portion of the input radiation as reflected radiation, and provides distributed feedback of the reflected radiation to the laser cavity. 61. The solid-state laser of claim 60, wherein the VBG element is also an active medium. 62. The solid-state laser of claim 60, further comprising an active medium attached to the VBG element. 63. The solid-state laser of claim 60, wherein a resonator transverse mode is formed in free space. 64. The solid-state laser of claim 60, further comprising a waveguide, wherein a resonator transverse mode is formed in the waveguide.
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CROSS-REFERENCE TO RELATED APPLICATIONS This application claims benefit under 35 U.S.C. § 119(e) of provisional U.S. patent applications Nos. 60/484,857, filed Jul. 03, 2003, and 60/564,526, filed Apr. 26, 2004. The respective disclosures of each of the above-referenced patent applications are incorporated herein by reference. The subject matter disclosed and claimed herein is related to the subject matter disclosed and claimed in U.S. patent application Ser. No. 10/390,521, filed Mar. 17, 2003, the disclosure of which is hereby incorporated herein by reference. FIELD OF THE INVENTION The invention is related generally to light emitting devices, such as lasers, laser diodes, light-emitting diodes, super-luminescent laser diodes, etc. More specifically, the invention provides for using one or more volume Bragg grating (VBG) elements for modifying (or conditioning) one or more output characteristics of such devices. BACKGROUND OF THE INVENTION Laser cavities or resonators, however complex, typically include two or more mirrors or other reflecting devices that form a closed optical path for rays traveling in a certain direction. An optical element positioned in that closed optical path, which includes mirrors and/or other reflecting devices that form the path, may be referred to as “intra-cavity.” An optical element positioned in the path of light that has departed from the resonator may be referred to as an “extra-cavity” element. Using extra-cavity partial reflectors as feedback elements with a solitary laser cavity has been attempted in the past with a purpose of achieving single longitudinal mode operation of the otherwise multi-mode laser. Such reflectors, however, were not wavelength-selective devices. Such designs may be referred to as the “coupled-cavity” approach. This approach suffered from instabilities stemming from the non-selective nature of the feedback. Another approach used was to employ a dispersive element, such as surface diffraction grating, as an extra- or intra-cavity wavelength-selective device in order to induce narrow-band or single longitudinal mode operation of a semiconductor laser. Although successful in a laboratory, this approach results in rather bulky devices, which are difficult to align and to maintain in the field. A somewhat more practical approach for inducing narrowband operation of a single-transverse mode semiconductor laser proved to be a fiber Bragg grating functioning typically as an extra-cavity element. This device is a narrow-band reflector that functions only in an optical fiber waveguide. It is, therefore, inapplicable to solid-state lasers, laser diode arrays, and, most likely, even to multi-mode (transverse) broad-area high-power single-emitter laser diodes, whether fiber-coupled or not. The use of a volume Bragg grating element has been suggested as an intra-cavity element to induce single-longitudinal mode (also called single-frequency) operation of a single-transverse mode laser diode. In this approach, the volume Bragg grating element forms the external Bragg mirror of an external-cavity single-spatial mode semiconductor laser diode. However, to the inventors' knowledge, neither the possibility of using a VBG element for extra-cavity narrow-band feedback nor a practical device for achieving narrow-band operation of a single-transverse mode semiconductor laser diodes have been disclosed previously. Furthermore, to the inventors' knowledge, not even the possibility of applying VBG elements to multiple-transverse mode, broad-area laser diodes, laser diode arrays or the possibility of conditioning other attributes of laser emission (such as its spatial mode and temporal profile) have been disclosed previously. To the inventors' knowledge, there are currently no devices in the market that employ volume Bragg grating elements for conditioning of laser characteristics, nor are there any successful practical devices in the market that use any of the above-mentioned approaches to improve the output characteristics of arrays of lasers. SUMMARY OF THE INVENTION The invention provides methods and apparatuses that can overcome the problems known in the prior art. The invention provides several practical embodiments of using VBG elements for conditioning any or all of the output characteristics of lasers and other light-emitting devices. The inventors have found that volume Bragg grating (VBG) elements recorded in photorefractive materials, particularly those recorded in inorganic photorefractive glasses (PRGs), have many properties that can improve one or more characteristics of light-emitting devices such as solid-state lasers, semiconductor laser diodes, gas and ion lasers, and the like. A volume Bragg grating (“VBG”) element may be any structure that: a) has a periodically varying index of refraction in its bulk (the shape of the surface of the constant index of refraction can be any smooth figure, flat or curved); b) is generally transparent in the spectral region of its operation; and c) has a thickness in the direction of propagation of light of 0.05 mm or more. A photorefractive material may include any material that has the ability to change its index of refraction subsequent to illumination by light of certain wavelength region or regions. Such a change in refractive index may occur in the material either immediately upon illumination by light or as a result of secondary processing step or steps, whether chemical, thermal, etc. Such a material may also be generally transparent in the spectral region of its photosensitivity, i.e. the light at the recording wavelength may have the ability to penetrate sufficiently deep into the material (>0.1 mm) without suffering excessive absorption (>90%). Further, the material may be amorphous and generally isotropic. Though the embodiments described herein are directed to certain examples of laser devices, it should be understood that the principles of the invention apply to other light-emitting devices as well. For example, applications of this invention include but are not limited to: high-power, semiconductor, solid state, ion, and gas lasers; light-emitting diodes and super-luminescent laser diodes; medical diagnostics, treatment, and surgical instruments; environmental sensors; metrology instruments; industrial applications; and defense applications. Properties of VBG elements, and methods for manufacturing VBG elements, have been described previously (see, for example, U.S. patent application Ser. No. 10/390,521, filed Mar. 17, 2003). Generally, there are at least three distinct characteristics of the output of a laser device that may be improved using the techniques of the invention: 1) emission spectrum (e.g., peak wavelength of the laser emission and its spectral width); 2) spatial/angular beam characteristics (e.g., the angular divergence of the output laser beam and its spatial mode structure); and 3) temporal profile of the laser pulses (e.g., the duration of the laser pulse, its temporal phase variation or chirp etc.). As used herein, spectral, spatial, or temporal conditioning, refer to affecting any of the above characteristics, respectively. The inventors have found that VBG elements permanently recorded in a suitable material, particularly a PRG, have a number of properties that can be utilized for improving one or more of the above characteristics. These properties include, but are not limited to: 1) single spectral pass band without any extraneous pass bands; 2) ability to control the spectral width of the VBG filter pass band; 3) ability to control the amplitude and phase envelope of a VBG filter; 4) narrow acceptance angle range otherwise called field of view; 5) ability to control the acceptance angle and the field of view; 6) ability to multiplex more than one filter in the same volume of the material; 7) high damage threshold of the VBG elements manufactured in a suitable material, particularly PRG; 8) ability to be shaped into bulk optical elements with sufficiently large clear aperture; and 9) reflectivity distributed over the volume of the material. The invention provides apparatus and methods by which these properties of VBGs may be applied to the improvement of the above-mentioned laser characteristics. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1C depict a VBG as an extra-cavity element for wavelength locking by self-seeding; FIG. 1D provides plots of wavelength characteristics with and without laser conditioning. FIGS. 2A and 2B depict wavelength locking by use of a transmission VBG. FIG. 3 depicts a wavelength stabilization concept for a high-power laser bar. FIGS. 4A and 4B depict wavelength locking by self-seeding for a multi-mode laser diode bar. FIG. 5 depicts locking of a laser diode array by use of a hybrid element combining the fast axis collimating lens and a VBG. FIG. 6 depicts wavelength locking of laser diode stacks. FIG. 7 depicts laser wavelength stabilization by self-seeding through a back-facet. FIG. 8 depicts a wavelength-shifted laser diode bar/stack. FIG. 9 depicts wavelength multiplexing of the output of a wavelength-shifted laser diode bar/stack for higher brightness. FIG. 10 depicts a VBG mirror forming part of a laser cavity. FIG. 11 depicts using a VBG for a single longitudinal laser mode selection. FIGS. 12A and 12B depict using a VBG element for selection of a single longitudinal mode of a laser in distributed feedback configurations. FIG. 13 depicts spatial mode stripping by use of a VBG. FIGS. 14A-14D depict examples of various angular diffraction efficiency profiles of VBG elements for spatial mode stripping in non-folding configurations. FIG. 15 depicts simultaneous single longitudinal mode and TEM00 mode selection by use of VBG element with smoothly varying reflectivity profile. FIG. 16 depicts conditioning of the temporal profile of pulsed lasers. FIGS. 17A-17C depict how a VBG may be used to construct tunable devices. FIGS. 18A and 18B depict simultaneous spectral and spatial conditioning, and combining of the output of an array of emitters by use of an external feedback filtered through a wavelength multiplexing device. FIG. 19 depicts the results of spectral conditioning of laser diodes by use of VBG in extra-cavity configuration. FIG. 20 depicts the output power characteristics of a laser diode locked by an external VBG element. FIG. 21 depicts the results on the improvement in thermal drift of a laser diode locked by an external VBG element. FIG. 22 depicts the results in improving spatial characteristics of a laser diode locked by an external VBG element. FIGS. 23A and 23B depict an embodiment for extra-cavity doubling of a high-power laser diode frequency. FIGS. 24A-24C depict another embodiment for extra-cavity doubling of a high-power laser diode frequency. FIGS. 25A and 25B depict intra-cavity doubling of a high-power laser diode frequency. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Overview There are at least two general approaches to using VBG elements for conditioning a characteristic of a light emitting device: a) using a VBG that is outside of the laser cavity (extra-cavity); and b) using a VBG that is inside laser cavity (intra-cavity). As discussed above, a laser resonator may be viewed as a closed optical path formed between mirrors and/or other light-reflecting elements. Such a closed optical path is typically a condition that is necessary for lasing to occur. For this reason, it is desirable that any intra-cavity element added to the resonator does not alter this condition, lest it impede light generation via stimulated emission. By contrast to intra-cavity elements, extra-cavity elements may be free from such a constraint. Furthermore, the efficiency of light generation typically depends nonlinearly on single-pass cavity loss. Thus, it is also desirable that any intra-cavity element used for laser output conditioning have as little loss as possible. This includes the losses in the element itself, as well as the losses in the optical delivery system used to project light onto the element and back. In contrast, extra-cavity elements used for laser output conditioning may be much more tolerant to the loss factor. When used for narrowing the spectral output of a laser, intra-cavity elements provide wavelength-selective loss that raises the lasing threshold for all but a few cavity modes. In contrast, the feedback from an extra-cavity wavelength-selective element reduces lasing threshold for just a few cavity modes, which creates preferred lasing conditions for those modes. These modes, then, consume most or all of the available laser gain and prevent other modes from lasing. Similar processes affect the formation of the spatial mode of the laser when intra- and extra-cavity elements are used for spatial mode conditioning. An optical delivery system may be viewed as a collection of optical elements, e.g. lenses, mirrors, prisms etc., that collects some or all of the light emanating from a particular aperture of the laser cavity, projects some or all of this light onto a VBG element or a system thereof, and then collects some or all of the light returned from said VBG element and projects it back onto the aperture of laser cavity. When considering the intra-cavity use of VBG elements, a design factor that may be considered is the reduction of the total loss of the VBG element plus the optical delivery system for the preferred longitudinal and transverse modes of the laser. In comparison, the design of an extra-cavity system for laser output conditioning may be more complex. In order to achieve stable output with desired characteristics, it may be desirable to optimize any or all of the following factors: 1) The solitary cavity design, including, but not limited to, cavity length, reflectivity of the cavity mirrors, threshold, differential efficiency, etc., all of which may be dependent on the properties of the gain medium; 2) The intrinsic reflectivity and loss of the VBG element; 3) The spectral bandwidth of the VBG element; 4) The reflectivity of the VBG element facets; 5) The relative angle between the volume Bragg grating planes and the external facets of the element; 6) The design of the external optical delivery system projecting light onto and back from the VBG element, including, but not limited to, its total coupling efficiency into the solitary laser cavity, the length of the external cavity, the divergence of the light (in both directions) incident upon the VBG and the output coupler of the solitary cavity, etc. For example, single-transverse mode laser diodes that are stabilized by a fiber Bragg grating may have such a fiber Bragg grating positioned rather far from the laser diode chip (typically about 1 meter) in order to induce the so-called coherence collapse regime of operation. Such a condition may be necessary to achieve stable laser output. However, if a VBG element was used as a mere free-space replacement of the fiber Bragg grating, it may result in a device 1.5 m long without an advantage of easy coiling or folding that the optical fiber affords naturally. Such a device might not be practical, however, and, therefore, different stable operating conditions might be desirable for devices using VBG elements for laser output conditioning, which are the result of the optimization of the above-described parameters. Extra-cavity Use of VBG Elements A VBG element may be used extra-cavity to condition, spectrally, spatially, and/or temporally, light received from a light-emitting device. At least a portion of the conditioned light may then be fed back into the laser cavity. In the process of doing so, the light emitted from the laser will assume the characteristics of the light conditioned by the VBG. Example embodiments of such extra-cavity use of VBG elements are depicted in FIGS. 1-9. Note that, when the VBG is used in extra-cavity configuration, the laser device is operating above threshold in the absence of optical feedback from the VBG element. In an example embodiment, a VBG element and a laser output coupler may be positioned in conjugate planes. An optical system including one or more lenses may be positioned in the light path after the light exits the laser cavity through the output coupler. Such an optical system may form an image of the output coupler in a particular location in space outside the laser cavity. A VBG element may be positioned in that plane so that the VBG element reflects the light rays incident upon it in such fashion that the reflected rays go back through the imaging optical system and form an image in the plane of the output coupler. In this case, it may be said that the output coupler and the VBG are positioned in the conjugate planes of the imaging optical system. A feature of this configuration is that it maximizes the coupling efficiency from the external element (the VBG element in this case) back into the laser cavity, essentially matching the resonator mode pattern in both transverse directions. Such an embodiment may be desirable where the laser cavity is a waveguide, such as in the case of semiconductor laser diodes, for example. In another example embodiment, the output of a waveguide laser cavity (e.g., a semiconductor laser diode) may be approximately collimated in one axis (e.g., the fast axis) by a cylindrical lens. The other axis (e.g., the slow axis) of the laser output may be allowed to diverge freely. The VBG element may be positioned in the optical path of the laser output behind the cylindrical lens and aligned in such a way that it reflects portion of the laser light back into the laser cavity. In this embodiment the coupling efficiency of the optical delivery system (e.g., the cylindrical lens) from the VBG back into the laser cavity is very low, making it undesirable for use as an intra-cavity element. However, such a system may be designed to operate stably in an extra-cavity configuration. It will induce wavelength-stable, spectrally narrowed operation of the laser diode. In this configuration the divergence of the non-collimated laser axis (the slow axis) can also be reduced without the use of additional optics, when such a laser is a broad-area multiple transverse mode semiconductor laser diode. In this configuration an entire linear array of semiconductor lasers can be conditioned with a single cylindrical lens and a single VBG element. An example embodiment of a broad-area high-power semiconductor laser, having an emitting aperture of greater than about 50 μm, with output conditioned by an extra-cavity VBG with a cylindrical fast-axis lens, is also disclosed. The output power of the laser changes rather insignificantly despite the fact that the VBG reflectivity is relatively high (30%). Small reduction in the output power is a factor in the design of practical systems using high-power laser diodes and may be provided by the invention. Example design parameters for stable operation of broad-area semiconductor laser diodes may include: laser cavity, 1-3 mm long; emitting aperture, 100-500 μm; back facet reflectivity, 0.9 or greater; front facet reflectivity, 0.5-20%; FAC lens EFL, 50-2000 μm; FAC lens type, graded-index cylindrical or plano-convex aspheric cylindrical; FAC AR coating, all facets<2%; VBG reflectivity, 5-60%; VBG thickness, 0.2-3 mm; VBG position behind FAC lens, 0-10 mm; and angle of the VBG planes with respect to its facet, 0-5 degrees. An example embodiment of an extra-cavity VBG without any optical delivery system (e.g., without any lenses) is also disclosed. In this embodiment a VBG element may be positioned in the optical path of the light behind the output coupler (e.g., the laser diode front facet) without any extra optical elements (e.g., lenses) in between. In the case of a waveguide cavity, such as the case for semiconductor laser diodes, only a very small portion of the total laser output power may be returned by the VBG into the laser cavity. However, with proper laser cavity and VBG design, it is possible to achieve spectral narrowing and stabilization of the output wavelength across a range of operating conditions. Example design parameters for such an embodiment may include: laser cavity, 1-3 mm long; emitting aperture, 100-500 μm; back facet reflectivity, 0.9 or greater; front facet reflectivity, 0.2-5%; VBG reflectivity, 30-99%; VBG thickness, 0.05-3 mm; VBG position in front of the laser, 0-5 mm; and angle of the VBG planes with respect to its facet, 0-5 degrees. Some of the embodiments described herein demonstrate how the output of a laser diode, laser diode bar, or stack may be modified spectrally and/or spatially. Effects of the VBG element in these cases include spectral narrowing of the emission line of a laser or laser array, stabilization of the peak emission wavelength of a laser or a laser array, and the reduction of the divergence of the slow axis of a laser or a laser array. Note that the high total output power of the laser transmitting through the clear aperture of the VBG (>20 W for laser diode arrays), the high power density on the VBG element (>40 W/cm2) as well as high temperature excursions suffered by such an element (T>100 C) may limit the choice of suitable materials for VBG implementation. Nevertheless, the inventors have successfully demonstrated VBG elements operation in all of the above conditions when implemented in PRG materials. FIG. 8, for example, demonstrates how both of these properties may be utilized in order to combine the output of an entire array of lasers onto a single target using a single VBG. In that embodiment, the VBG element contains a grating having a period that varies depending on location. When positioned properly in front of an array of emitters, such a grating will force different emitters to operate at a different peak wavelength depending on their location, creating a wavelength-shifted laser array. The output of such an array may be subsequently combined by use of one of a number of well-known wavelength multiplexing techniques into a much brighter spot with intensity essentially equivalent to that of the entire array and spatial dimensions essentially equivalent to that of an individual emitter. An embodiment for spectral power combining of a laser diode array via external feedback through a wavelength multiplexer is also disclosed. In this embodiment, a wavelength multiplexer may be positioned in the path of output light of an array of emitters and behind an optical delivery system. Such a multiplexer may be designed to combine the output of all the emitters into one beam, provided they operate at the wavelengths matching the appropriate input channels of the multiplexer. Such a condition may be achieved automatically when an external feedback is provided into the emitters from a partial reflector positioned in the light path behind the wavelength multiplexer. In this configuration, the reflected light will travel back through the multiplexer and separate into multiple channels different in wavelength. As a result, each of the emitters in the array will receive feedback at a wavelength matching that of the corresponding channel of the multiplexer. Such feedback will force each emitter to operate at appropriate wavelength, so that their output power is efficiently combined. Other applications include, but are not limited to, stabilization of super-luminescent laser diodes, light-emitting diodes, solid-state lasers, gas and ion lasers; wavelength stabilization of sources used in telecommunications, sensing, metrology, material processing, other industrial applications and defense electronics; multi-wavelength emitters and emitter arrays for use in any of the application areas mentioned above; and tunable-wavelength emitters. Intra-cavity Use of VBG Elements VBG elements may be used inside a laser cavity, rather than through an external feedback, to affect laser output directly. Examples of embodiments of intra-cavity use of VBG elements are provided in FIGS. 10-16. A VBG may be used to force a laser to operate on a single longitudinal mode. Due to the highly selective reflectivity of a VBG reflector, only one longitudinal mode of the laser cavity has gain exceeding the lasing threshold. Conventionally, monolithic or air-spaced etalons are used to select a single longitudinal mode of a solid-state laser (e.g., Nd:YAG). Very often, additional elements (e.g., thin etalon or a birefringent filter or both) are employed in order to achieve single-frequency operation, even for a narrow gain-bandwidth medium. It may be desirable that these elements, which provide wavelength-selective loss inside the cavity, are tuned in synch with each other and with the length of the main cavity in order to provide continuous, hop-free tuning. There are numerous ways to achieve single longitudinal mode (or single frequency) operation, with some of the embodiments described below. In one embodiment, a reflective VBG element may be used as the output coupler or the high reflector of a laser resonator. The length of the VBG element may be selected in such a way that its reflectivity drops rapidly when the wavelength is detuned from the Bragg condition. Consequently, only one resonator mode reaches lasing threshold. In another embodiment, two VBG elements may be employed—one as the high reflector and one as an output coupler of the laser resonator. The VBG elements may have slightly shifted peak reflectivity wavelengths, which creates more rapid change in cavity loss with wavelength. This would allow the use of shorter, less selective VBG elements and/or longer laser resonators. In yet another embodiment, the VBG may act as a distributed feedback (DFB) element, taking place of both resonator mirrors. Such an element may be monolithic, with proper phase shift between the two halves of the Bragg grating. In this embodiment, the active medium may be the VBG itself, which can be achieved with proper doping with active ions, or the active medium can be attached to the VBG element along the length of the Bragg grating, partially or entirely. It may be desirable that a laser output include only one (e.g., the lowest) spatial mode, which in free-space resonators has the designation TEM00. This mode has a smooth intensity profile and the lowest possible angular divergence. However, such TEM00 operation is often rather difficult to achieve in high-power lasers with high single-pass gain. The techniques for achieving TEM00 operation usually rely on the differences in the spatial and angular profile of the TEM00 and the higher modes by introducing an element or elements with position-dependent loss (apertures) or angle-dependent loss. VBGs are well suited to serve in either capacity. Glebov, et al., have disclosed an approach for using a transmission-type VBG element inside a solid-state laser cavity to provide an angle-dependent cavity loss. However, that approach uses a VBG as an intra-cavity folding element that has very high angular sensitivity and requires very delicate and extremely accurate alignment. If the alignment of such a folding element is disturbed, the laser generation will seize, which makes this approach undesirable. A preferred approach would be to use a mode-forming element that by itself does not require critical alignment and, when perturbed, would not stop laser operation, but rather allow higher spatial modes to achieve lasing threshold, at most. This requires an element or elements that have low loss for TEM00 mode, have high loss for all higher modes, and do not alter the optical path of the TEM00 mode. This class of intra-cavity mode-forming elements may be referred to as “non-folding” mode-forming or mode-stripping elements. It should be understood that the diffraction efficiency of a VBG element depends on the angle of incidence for a given wavelength of light. For this reason, it will produce an angle-dependent gain/loss profile in the laser cavity. Such a gain profile will create higher losses for spatial modes higher than TEM00 and, therefore, can be used for suppressing higher spatial mode in the laser resonator (“mode-stripping”), resulting in a clean TEM00 output of the laser. To function as a spatial mode-stripping device, a VBG element may have a variety of angular diffraction efficiency profiles, such as those provided and described below in connection with FIG. 12. It should be understood that other possible types of angular profiles of diffraction efficiency of a VBG element may lead to the desired effects on the output of a laser. It should also be understood that reflection and transmission type VBG elements, as well as hybrid elements, may be utilized to achieve the desired effect. The principles of the invention may be applied to any or all of these cases without limitation. An example embodiment of a non-folding mode-forming element is a VBG mirror with a Gaussian or super-Gaussian reflectivity profile. In this embodiment, a reflective VBG element may have an axially-symmetric reflectivity profile with smooth radial variation of the reflectivity following, preferably, a super-Gaussian shape. Such an element, when used either as an output coupler or the high reflector of the laser cavity, may be designed to overlap spatially with the TEM00 mode at that particular location within the resonator, but it would have high losses for all the higher resonator modes. Such a VBG element with a soft aperture may have either plane parallel Bragg planes (e.g., a zero optical power VBG element) or have Bragg planes designed to have a particular curvature (e.g., a VBG element with finite optical power). Another embodiment includes the use of a transmissive, non-folding VBG element to diffract higher resonator modes away from the resonator optical axis. This approach relies on the high angular selectivity of the transmissive VBGs and may be made with such angular reflectivity profile that the TEM00 mode is transmitted through such an element without being diffracted, that is, with little or no loss. Several or all of the higher modes, starting with TEM01/TEM10, may experience sufficient diffraction, and, therefore, loss, such that they do not reach the threshold for lasing. Such a VBG element may or may not have axial symmetry in its angular profile of the diffraction efficiency. Yet another example embodiment is based on the natural angular selectivity of a reflective VBG. Such a VBG element, serving as the output coupler or the high reflector of the laser cavity, would have high reflectivity for the incident waves of a particular wavelength near the normal to the grating planes, but the reflectivity would drop rapidly for the waves incident upon such VBG element at an angle outside its angular acceptance. Therefore, the VBG element would satisfy the three criteria for non-folding mode-forming elements outlined above. The amplitude and phase envelope of the VBG may be adjusted in order to produce a desired effect on the temporal profile of ultra-short laser pulses. One particular example is the compensation of pulse chirping produced inside the laser cavity by other elements, such as the laser gain medium. Detailed Descriptions of Example Embodiments Depicted in the Figures FIGS. 1A-C illustrate applications of a VBG as an extra-cavity element for wavelength locking via self-seeding, that is, where the VBG element provides wavelength-selective feedback into the laser cavity. FIG. 1A shows wavelength locking and narrowing by use of an optical delivery system 104. Laser radiation 102 is emitted from the emitting aperture of a laser 100. The optical delivery system 104 redirects the emitted radiation 102, as a redirected emission 105, onto a VBG element 106. Radiation 107 is reflected by the VBG element 106. The optical delivery system 104 redirects the reflected radiation 107, as redirected reflected radiation 103, back onto the emitting aperture of the laser 100. The redirected reflected radiation 103 acts as a narrow-wavelength seed, forcing the laser 100 to operate at the wavelength of the VBG 106 and also narrowing its emission spectrum. As shown in FIG. 1B, laser radiation 112 is emitted from the emitting aperture of a laser 110. An optical delivery system 114 collimates the emitted radiation 102, as collimated radiation 115, onto a VBG element 116. The VBG element 116, having a narrow-wavelength reflectance, reflects at least a portion 117 of the laser energy back through the optical delivery system 114 and into the laser cavity of the laser 110. The reflected radiation 117 acts as a narrow-wavelength seed, forcing the laser 110 to operate at the wavelength of the VBG 116 and also narrowing its emission spectrum. FIG. 1C shows wavelength locking by a VBG element without an optical delivery system. As shown, laser radiation 122 is emitted from the emitting aperture of a laser 120 and is incident onto a VBG element 126. The VBG element 126, having a narrow-wavelength reflectance, reflects at least a portion 127 of the laser energy back into the laser cavity of the laser 120. The reflected radiation 127 acts as a narrow-wavelength seed, forcing the laser 120 to operate at the wavelength of the VBG 126 and also narrowing its emission spectrum. FIG. 1D provides plots of wavelength characteristics with and without laser conditioning. As shown, the conditioned radiation (e.g., radiation 103, 117, 127) has a bandwidth, b2, that is much more narrow than the bandwidth, b1, of the unconditioned radiation (e.g., radiation 102, 112, 122). Also, the peak intensity I2 of the conditioned radiation is greater than the peak intensity I1 of the unconditioned radiation. FIGS. 2A and 2B illustrate wavelength locking using an extra-cavity transmission VBG. The light 132 emitted by a laser 130 may be collimated by a lens 134 and is incident upon a VBG 136. The portion 135 of the light 132 having a wavelength within the passband of the VBG 136 is diffracted by the VBG 136, deflected from its original path. The diffracted light 135 is incident upon a reflective surface 138, which may be formed on the VBG element itself, as shown in FIG. 2A, or provided as an external element, as shown in FIG. 2B. Upon being reflected by the surface 138, the reflected diffracted light 139 is redirected by the VBG element 136, as redirected light 137 back through the lens 134 and into the laser cavity of the laser 130. Thus, the laser 130 may be forced to operate at a wavelength determined by the VBG 136. FIG. 3 depicts the output of a laser diode bar 140 locked by a single VBG element 146 using a single micro-lens 144. The radiation output by the laser diode bar 140 may be collimated on an axis (say, the y-axis as shown in FIG. 3) by the micro-lens 144, which may be a cylindrical lens, for example, and is incident upon the VBG element 146. The VBG element 146, which may have generally the same grating period through its entire volume, reflects at least a portion of the light back into the cavities of the individual emitters 141 in the bar 140. The effect produced on the output of the emitter array is essentially the same as on an individual emitter. As a result, the output of the entire bar 140 is locked to one wavelength determined by the VBG element 146. FIGS. 4A and 4B illustrate the use of a cylindrical lens 144 for locking a bar 140 of multimode laser diodes 141. FIG. 4A shows a cross-section of the laser diode bar 140. The light emitted by the laser bar 140 may be collimated or reduced in divergence on the fast axis (y-axis as shown in FIG. 3) by the cylindrical lens 142 and is incident upon the VBG element 146. The VBG element 146 reflects some light back into the laser cavity. FIG. 4B shows the top view of the laser diode bar 140. The light emitted by the individual emitters 141 in the diode bar 140 is incident upon the cylindrical lens 142. The slow axis of the emitted light cone is not collimated. It is subsequently incident upon the VBG element and is reflected back onto the face of the diode bar. FIG. 5 shows how a hybrid optical element 148, which may be a combined lens and VBG element, can be used for conditioning of an entire array 140 of emitters 141. The lens portion 146 of the hybrid optical element 148 can be formed directly on the surface of the VBG element 144 or seamlessly fused onto it. FIG. 6 shows the concept of locking a stack 150 of diode bars 151. There are several diode bars 152 in the stack 150, each of which includes a plurality of individual emitters 151 exposed at the face of the stack 150. The light emerging from the individual emitters 151 may be collimated by a set of cylindrical micro-lenses 154. Preferably, a respective lens 154 is provided for each diode bar 152 (though it should be understood that other lens arrangements may be used as well). The lenses 154 collimate the fast axes of the bars 152 and the emitted light subsequently enters the VBG element 156. The VBG element 156 may have essentially the same period grating through its entire volume. The VBG element 156 reflects at least a portion of the incident light back through the lenses 154 onto the face of the stack 150, with at least a portion of the reflected light entering the cavities of the individual emitters 151. The result is that the output of the entire stack 150 is locked to the same wavelength determined by the VBG element 156. FIG. 7 depicts locking a light emitter 160 by placing a VBG element 166 behind the back facet of the emitter 160. The back facet of the emitter 160 is partially transmissive to light. The light exiting that facet is collimated by an optical delivery system (e.g., a lens) 164 and then is incident upon the VBG element 166. The VBG element 166 reflects at least a portion of this light back onto the back facet of the emitter 160, with at least a portion of the reflected light entering the laser cavity of the emitter 160. This results in locking the wavelength of the emitter 160 to that of the VBG element 166. FIG. 8 depicts producing an array of emitters with different wavelength outputs. This concept may be applied to either one- or two-dimensional arrays. All the emitters 171 in the array 170 may be made from the same material, and, therefore, may have essentially the same natural output wavelength. The light emerging from the individual diode bars 172 in the stack 170 may be collimated by a set of cylindrical micro-lenses 174. Preferably, a respective lens 174 is provided for each diode bar 172 (though it should be understood that other lens arrangements may be used as well). The lenses 174 collimate the fast axes of the bars 172 and the emitted light subsequently enters the VBG element 176. The grating period of the VBG element 176 may differ depending on the location along the grating coordinate parallel to the laser bar(s) 172. The VBG element 176 reflects at least a portion of the incident light back onto the face of the stack 170, and at least a portion of the reflected light enters the cavities of the individual emitters 171. As a result, the emitting wavelength of the individual laser diodes 171 in the bar(s) 172 may be locked to different values depending on the location of the emitters 171 relative to the VBG 176. FIG. 9 depicts wavelength multiplexing of the output of the wavelength-shifted laser diode bar/stack 170 described in FIG. 8 to produce a higher brightness light source. The output of an array of emitters 170 is conditioned by a lens or lens array 174 and subsequently enters a VBG element 178. The VBG element 178 has a grating period that may vary depending on the location along the grating coordinate parallel to the array of the emitters 170. The VBG element 178 thus forces the individual emitters to operate at different wavelengths depending on the location within the array. The output of such a wavelength-shifted emitter array may be directed into a wavelength multiplexer 180 capable of multiplexing different wavelengths of light into a single output. Such a multiplexer 180 may be constructed using any of a number of well-established techniques, including, but not limited to diffraction gratings, VBG elements, thin-film dielectric filters, arrayed-waveguide grating(s), or any other optical elements or a combination of optical elements capable of delivering this basic function. The output of the entire emitter array 170 may thus be combined into a single spot with essentially all optical power of the entire array concentrated in one spot on a target (not shown), which can be or include, without limitation, an optical fiber, optical fiber array, detector, detector array, emitter, emitter array, solid-state material that needs to be processed (e.g., cut, welded, melted, etc.), liquid, gas, or the like. FIG. 10 depicts a VBG element 202 inside a laser cavity 200. The laser cavity 200 may include one or more mirrors 208 (back facet, as shown, or front facet, not shown), a gain medium 206, conditioning optics 204, and a VBG element 202. Preferably, the gain medium 206 may be or include a solid-state, gas, or ion medium, and the conditioning optics may include lenses, mirrors, prisms, birefringent filters, and the like. It should be understood, however, that any type of gain medium and conditioning optics may be used. Also, the gaps shown in FIG. 10 between the individual components within the laser cavity 200 may or may not be employed. The function of the VBG 202 may be spectral, spatial, or temporal conditioning of the laser output. FIG. 11 provides plots showing how a VBG element can force a laser to operate on a single longitudinal mode. As an example, a VBG element may be used as a partially reflective output coupler. The VBG element has a narrow wavelength reflectivity, considerably narrower than the width of the gain curve of the active medium of the laser. In order to lase, the individual longitudinal modes of the laser resonator have to exceed the lasing threshold. Due to the highly selective reflectivity of a VBG output coupler, however, only one longitudinal mode of the laser cavity has a gain exceeding the lasing threshold. FIGS. 12A and 12B depict a VBG element used as a distributed feedback element of a solid-state laser. As shown in FIG. 12A, the VBG element 210 can serve as both the active medium and the feedback element. As shown in FIG. 12B, the VBG element 212 can be attached via an optical contact (e.g., fused) to the active medium 214. The resonator mode can be formed by either the VBG element itself or some additional elements. Both configurations can be used in free-space or waveguide applications. Similar to narrow wavelength pass-band, a VBG element may have a narrow angle pass-band, as shown in FIG. 13. Preferably, the angular passband of the VBG element should be wider than the angular width of the TEM00 mode of the laser cavity. Due to the relatively sharp roll-off of the diffraction efficiency of a VBG element with angle of incidence (the laser wavelength is fixed), a higher mode of the laser cavity will experience higher losses and, therefore, will be essentially suppressed by the VBG element. The VBG element thus functions to strip the laser from its higher spatial modes and force it to operate on the TEM00 mode only. As shown in FIGS. 14A and 14B, the VBG element has a high diffraction efficiency for the TEM00 mode only and produces higher loss for the higher spatial modes. The drawing on the right shows an embodiment of how it can be used in a laser cavity, comprising at least one mirror 224, a gain medium 222, and a VBG element 220 functioning as an output coupler. The VBG element 220 may have high reflectivity, and, therefore, low losses, only for the TEM00 mode. By contrast, as shown in FIGS. 14C and 14D, the VBG element 230 may have a diffraction efficiency profile with a dip at nearly normal incidence, both in azimuth and elevation angle profile. Therefore, it will have low loss for the TEM00 mode in transmission. Such a VBG element 230 may be used as an essentially transparent (i.e., lossless) element inside the laser cavity, which may include at least one mirror 234 and a gain medium 232. Feedback may be provided by a conventional output coupler 236, for example, or by a VBG output coupler with angular diffraction efficiency profile as is shown in FIG. 14A. In the embodiment shown in FIG. 14D, the higher spatial modes will experience diffraction on the VBG element 230 and, therefore, will be directed out of the cavity, producing higher losses for those modes and, therefore, eliminating them. In either case the result is TEM00 output of the laser. VBG elements of both transmission and reflection type can be used to achieve TEM00 operation. The embodiments depicted in FIGS. 14B and 14D are of the so-called “non-folding” type. FIG. 15 shows a concept for using a reflective VBG element with smoothly varying reflectivity profile (“soft aperture”) for inducing simultaneously single longitudinal mode operation of a laser as well as TEM00-only operation. The VBG element 232 depicted in FIG. 15 functions as the output coupler of the laser cavity 230, and is axially symmetric around the resonator axis Z. The laser cavity 230 may include a high-reflectivity mirror 236 and a gain medium 234. FIG. 16 depicts an embodiment suitable for shaping the temporal profile of ultra-short laser pulses. In this embodiment, a VBG element 240 may be used inside a laser cavity having at least one mirror 246, a gain medium 244, and other optics 242 (such as lenses, prisms, gratings, and the like). It is known that ultra-short laser pulses (e.g., <10 ps duration) have wide spectral range and will, therefore, likely experience dispersion inside the gain medium. The gain medium may be bulk solid-state, fiber, planar waveguide or any other. Such dispersion is generally undesirable because it leads to broadening of the ultra-short laser pulse. In accordance with an aspect of the invention, the VBG element 240 may be manufactured with a grating period that varies slightly along the axis, z, of the laser. Such a grating may produce slightly different delays for different wavelengths and, therefore, will compensate for the dispersion of the gain medium 244 of the laser. This improves the temporal characteristics of the laser pulse. Alternatively, the same technique may be used for compression of the chirped and stretched high peak power ultra-short pulses subsequent to their amplification in an optical amplifier. The pulses must be stretched prior to the amplification to avoid damage to the amplifier as well as nonlinear effects. FIGS. 17A-C depict a VBG element used to construct tunable devices. As shown in FIGS. 17A and 17B, light emerging from the cavity of an emitter 250 may be collimated by a lens 252, if necessary, and incident upon a VBG element 254/264. FIG. 17A shows an embodiment using a reflective-type VBG element 254; FIG. 17B shows an embodiment using a transmissive-type VBG element 256. The VBG element 254/264 reflects or deflects the incident light at an angle onto a folding mirror/reflector 256. The folding mirror 256 may then redirect the light to a retro-reflector 258, which reflects the light back on its path. The light retraces it path back into the cavity of the emitter 250, forcing the emitter 250 to operate at the peak wavelength of the VBG filter. Since the peak wavelength of a VBG element 254/264 depends on the incident angle, rotation of the VBG / folding reflector assembly continuously tunes the emitted wavelength of light. As shown in FIG. 17C, light emerging from the cavity of an emitter 270 may be collimated by a lens 272, if necessary, and incident upon a VBG element 274. The VBG element 274 may have a period and peak wavelength that vary smoothly and continuously as a function of position across its clear aperture. Thus, the device may include a transverse chirp VBG reflector. When such a VBG element is translated across the output beam of the laser the wavelength of the laser emission will change to follow that of the particular location on the VBG element 274. It should be understood that, in the absence of an emitter, the VBG element (plus auxiliary optics) shown in FIGS. 17A-17C may function as a tunable filter. FIGS. 18A and 18B depict spectral/spatial conditioning of an array of emitters with simultaneous wavelength combining/multiplexing. The light emitted by each of the emitters in the array 284 is depicted going though a particular channel in a wavelength multiplexer 282 positioned in the optical path of light emitted by the array 284. The multiplexer 282 combines all different wavelength channels 286 into one output channel. The multiplexed light is partially reflected by a retro-reflecting device 280 and the reflected portion of the light retraces its path back into the different emitters in the array 284. As a result, each emitter in the array 284 receives wavelength-selective feedback and, therefore, will be forced to operate at the wavelength of the multiplexer channel 286 it is coupled to. Efficient spectral and spatial conditioning can be achieved in this way with simultaneous combining of the output of all the emitters in the array. FIG. 18B depicts an embodiment where such a multiplexer 282 is constructed of a monolithic glass chip with wavelength-specific VBG nodes 288 recorded in its bulk. FIG. 19 provides a comparison of the output spectrums of free-running and VBG-locked, single-emitter lasers. The laser diode parameters were: 2 mm cavity length, 1×100 μm emitting aperture, and approximately 0.5% front facet reflectivity. The VBG parameters were: approximately 30% maximum reflectivity, and 0.84 mm thickness. Shown in the inset is a comparison of the output spectrums of free-running and VBG-locked laser diode bars. The laser bar parameters were: 19 emitters, 1×150 μm emitting aperture for each emitter, and approximately 17% front facet reflectivity. The VBG parameters were: approximately 60% maximum reflectivity, and 0.9 mm thickness. FIG. 20 provides plots of output power vs. current for a single-emitter laser diode under different conditions. The laser diode and the VBG parameters were the same as those described in connection with FIG. 19. The inset provides plots of emission spectra of the laser diode at different currents when free-running and locked by the VBG. FIG. 21 provides plots of emission wavelength of a single-emitter laser diode as a function of the heatsink temperature when free running w/o FAC lens (circles) and locked by a VBG (squares). Drive current was 1.5 A in both cases. The VBG element was attached to the laser heatsink during the experiment. Shown in the inset is a plot of output power of a locked laser diode (squares) and a fast-axis collimated laser diode (circles) as a function of its heatsink temperature. FIG. 22 provides plots that demonstrate the effect of VBG locking on the divergence of the slow axis of a single-emitter laser diode. The dotted curve shows the calculated far-field pattern of the light diffracted on the exit aperture of the laser diode. FIGS. 23A and 23B depict extra-cavity doubling of a high-power laser diode frequency. As shown in FIG. 23A, light emitted by a laser diode 302 with a high-reflectivity (HR) coating on the back facet and an anti-reflection (AR) coating on the front facet is collimated by a lens 304 and is incident upon a VBG element 306. The VBG element 306 reflects a certain amount of light in a narrow spectral region. The reflected light is directed back into the cavity of the laser diode 302, thus locking the frequency of the laser emission to that of the peak reflectivity of the VBG element 306. The VBG element 306 also narrows the emission bandwidth of the laser 302, making it equal to or smaller than the acceptance bandwidth of the quasi-phase-matched (QPM) nonlinear crystal 310. The nonlinear crystal 310 is periodically poled to achieve QPM. The light that passes through the VBG element 306 may be focused into the QPM crystal 310 by a lens 308. The QPM crystal 310 generates the second harmonic of the light emitted by the laser diode 302. The QPM crystal 310 preferably has AR coating for the fundamental and the second harmonic on both facets. Light out of the QPM crystal 310 may be redirected through another lens 312. As shown in FIG. 23B, the VBG element 326 locks the frequency and narrows the emission spectrum of the laser diode 322. The laser diode 322 may have the same characteristics as described above in connection with FIG. 23A. The emitted light is focused into a QPM nonlinear waveguide 330, which generates the second harmonic of the incident light. The QPM nonlinear waveguide 330 preferably has AR coating for the fundamental and the second harmonic on both facets. Lenses 324, 328, and 332 may be provided as desired. FIGS. 24A-C depict extra-cavity doubling of a high-power laser diode frequency. Light emitted through the back facet by a laser diode 344 with AR coating on both facets is collimated by a lens 342 and is incident upon a VBG element 340. The VBG element 340 reflects most of the light in a narrow spectral region. The reflected light is directed back into the laser cavity, thus forming an external cavity and locking the frequency of the laser emission to that of the peak reflectivity of the VBG element 340. The front facet of the laser 344 should have enough reflectivity for the laser 344 to operate above threshold and at a desired output power level. The VBG element 340 also narrows the emission bandwidth of the laser 344, making it equal to or smaller than the acceptance bandwidth of the quasi-phase-matched (QPM) nonlinear crystal 348. A lens 346 may be used to focus the light into the QPM crystal 348, which then generates the second harmonic of the incident light. The QPM crystal 348 preferably has AR coating for the fundamental and the second harmonic on both facets. A lens 349 may be used to focus the light output from the QPM crystal. As shown in FIG. 24B, the light emitted by the laser diode 344 may be focused into a QPM nonlinear waveguide 358, via a lens 356. The waveguide 358 may generate the second harmonic of the incident light. The QPM nonlinear waveguide 358 preferably has AR coating for the fundamental and the second harmonic on both facets. As shown in FIG. 24C, the QPM nonlinear waveguide 358 abuts the laser diode 344 so that most of the light emitted by the laser diode 344 is coupled into the QPM waveguide 358. FIGS. 25A and 25B depict intra-cavity doubling of a high-power laser diode frequency. FIG. 25A depicts a high-power laser diode 370 having HR coating on the back facet and very low reflectivity AR coating on the front facet. The external cavity of the laser diode 370 may be formed by a VBG element 371 positioned after a collimating lens 379. A QPM crystal 378 may be placed between the VBG element 371 and the front facet of the laser diode 370, and between a lens pair 376, 379 that focuses the light into the QPM crystal 378. By having the QPM crystal 378 positioned inside the external cavity of the laser diode 370, the power of the fundamental harmonic of the laser diode 370 can be increased, thus increasing the conversion efficiency from the fundamental to the second harmonic. A window 374 with AR coating for the fundamental harmonic and HR coating for the second harmonic can be placed between the front facet of the laser diode 370 and the QPM crystal 378 in order to increase the total power of the second harmonic emitted by this device. The QPM crystal 378 preferably has AR coating for the fundamental and the second harmonic on both facets. As shown in FIG. 25B, the laser diode 370 may abut a QPM nonlinear waveguide 388. Preferably, the waveguide 388 has AR coating for the fundamental harmonic of light emitted by the laser diode 370 and HR coating for the second harmonic on its front facet (i.e., the one facing the laser diode 370). The back facet of the QPM nonlinear waveguide 388 preferably has AR coating for both the fundamental and the second harmonic. Thus, there have been described example embodiments of apparatus and methods for conditioning laser characteristics using volume Bragg grating elements. It will be appreciated that modifications may be made to the disclosed embodiments without departing from the spirit of the invention. The scope of protection, therefore, is defined by the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Laser cavities or resonators, however complex, typically include two or more mirrors or other reflecting devices that form a closed optical path for rays traveling in a certain direction. An optical element positioned in that closed optical path, which includes mirrors and/or other reflecting devices that form the path, may be referred to as “intra-cavity.” An optical element positioned in the path of light that has departed from the resonator may be referred to as an “extra-cavity” element. Using extra-cavity partial reflectors as feedback elements with a solitary laser cavity has been attempted in the past with a purpose of achieving single longitudinal mode operation of the otherwise multi-mode laser. Such reflectors, however, were not wavelength-selective devices. Such designs may be referred to as the “coupled-cavity” approach. This approach suffered from instabilities stemming from the non-selective nature of the feedback. Another approach used was to employ a dispersive element, such as surface diffraction grating, as an extra- or intra-cavity wavelength-selective device in order to induce narrow-band or single longitudinal mode operation of a semiconductor laser. Although successful in a laboratory, this approach results in rather bulky devices, which are difficult to align and to maintain in the field. A somewhat more practical approach for inducing narrowband operation of a single-transverse mode semiconductor laser proved to be a fiber Bragg grating functioning typically as an extra-cavity element. This device is a narrow-band reflector that functions only in an optical fiber waveguide. It is, therefore, inapplicable to solid-state lasers, laser diode arrays, and, most likely, even to multi-mode (transverse) broad-area high-power single-emitter laser diodes, whether fiber-coupled or not. The use of a volume Bragg grating element has been suggested as an intra-cavity element to induce single-longitudinal mode (also called single-frequency) operation of a single-transverse mode laser diode. In this approach, the volume Bragg grating element forms the external Bragg mirror of an external-cavity single-spatial mode semiconductor laser diode. However, to the inventors' knowledge, neither the possibility of using a VBG element for extra-cavity narrow-band feedback nor a practical device for achieving narrow-band operation of a single-transverse mode semiconductor laser diodes have been disclosed previously. Furthermore, to the inventors' knowledge, not even the possibility of applying VBG elements to multiple-transverse mode, broad-area laser diodes, laser diode arrays or the possibility of conditioning other attributes of laser emission (such as its spatial mode and temporal profile) have been disclosed previously. To the inventors' knowledge, there are currently no devices in the market that employ volume Bragg grating elements for conditioning of laser characteristics, nor are there any successful practical devices in the market that use any of the above-mentioned approaches to improve the output characteristics of arrays of lasers.
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<SOH> SUMMARY OF THE INVENTION <EOH>The invention provides methods and apparatuses that can overcome the problems known in the prior art. The invention provides several practical embodiments of using VBG elements for conditioning any or all of the output characteristics of lasers and other light-emitting devices. The inventors have found that volume Bragg grating (VBG) elements recorded in photorefractive materials, particularly those recorded in inorganic photorefractive glasses (PRGs), have many properties that can improve one or more characteristics of light-emitting devices such as solid-state lasers, semiconductor laser diodes, gas and ion lasers, and the like. A volume Bragg grating (“VBG”) element may be any structure that: a) has a periodically varying index of refraction in its bulk (the shape of the surface of the constant index of refraction can be any smooth figure, flat or curved); b) is generally transparent in the spectral region of its operation; and c) has a thickness in the direction of propagation of light of 0.05 mm or more. A photorefractive material may include any material that has the ability to change its index of refraction subsequent to illumination by light of certain wavelength region or regions. Such a change in refractive index may occur in the material either immediately upon illumination by light or as a result of secondary processing step or steps, whether chemical, thermal, etc. Such a material may also be generally transparent in the spectral region of its photosensitivity, i.e. the light at the recording wavelength may have the ability to penetrate sufficiently deep into the material (>0.1 mm) without suffering excessive absorption (>90%). Further, the material may be amorphous and generally isotropic. Though the embodiments described herein are directed to certain examples of laser devices, it should be understood that the principles of the invention apply to other light-emitting devices as well. For example, applications of this invention include but are not limited to: high-power, semiconductor, solid state, ion, and gas lasers; light-emitting diodes and super-luminescent laser diodes; medical diagnostics, treatment, and surgical instruments; environmental sensors; metrology instruments; industrial applications; and defense applications. Properties of VBG elements, and methods for manufacturing VBG elements, have been described previously (see, for example, U.S. patent application Ser. No. 10/390,521, filed Mar. 17, 2003). Generally, there are at least three distinct characteristics of the output of a laser device that may be improved using the techniques of the invention: 1) emission spectrum (e.g., peak wavelength of the laser emission and its spectral width); 2) spatial/angular beam characteristics (e.g., the angular divergence of the output laser beam and its spatial mode structure); and 3) temporal profile of the laser pulses (e.g., the duration of the laser pulse, its temporal phase variation or chirp etc.). As used herein, spectral, spatial, or temporal conditioning, refer to affecting any of the above characteristics, respectively. The inventors have found that VBG elements permanently recorded in a suitable material, particularly a PRG, have a number of properties that can be utilized for improving one or more of the above characteristics. These properties include, but are not limited to: 1) single spectral pass band without any extraneous pass bands; 2) ability to control the spectral width of the VBG filter pass band; 3) ability to control the amplitude and phase envelope of a VBG filter; 4) narrow acceptance angle range otherwise called field of view; 5) ability to control the acceptance angle and the field of view; 6) ability to multiplex more than one filter in the same volume of the material; 7) high damage threshold of the VBG elements manufactured in a suitable material, particularly PRG; 8) ability to be shaped into bulk optical elements with sufficiently large clear aperture; and 9) reflectivity distributed over the volume of the material. The invention provides apparatus and methods by which these properties of VBGs may be applied to the improvement of the above-mentioned laser characteristics.
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20040702
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20071120
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20050127
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78489.0
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NGUYEN, DUNG T
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USE OF VOLUME BRAGG GRATINGS FOR THE CONDITIONING OF LASER EMISSION CHARACTERISTICS
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UNDISCOUNTED
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ACCEPTED
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10,884,641
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ACCEPTED
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Adaptive transmission in multi-access asynchronous channels
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A hybrid transmission cycle (HTC) unit of bandwidth on a shared transmission medium is defined to include an adaptive, time division multiplexing transmission cycle (ATTC), which is allocated in portions sequentially among all participating network entities, and a residual transmission cycle (RTC), which is allocated in portions, as available, to the first network entity requesting access to the shared medium during each particular portion. The ratio of logical link virtual channels, or D-Channels, to data payload virtual channels, or B-Channels, within the ATTC is adaptive depending on loading conditions. Based on transmission profiles transmitted on the D-Channels during the ATTC, each network entity determines how many B-Channels it will utilize within the current HTC. This calculation may be based on any decision network, such as a decision network modelling the transmission medium as a marketplace and employing microeconomic principles to determine utilization. The ratio of the duration of the ATTC segment to the duration of the RTC segment is also adaptive depending on loading conditions, to prevent unacceptable latency for legacy network entities employing the shared transmission medium. During the RTC, utilization of the shared medium preferably reverts to IEEE 802.3 compliant CSMA/CD transmission, including transmissions by HTC-compliant network entities.
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1. A method of communication over a shared transmission medium, comprising: defining a transmission cycle having a first portion and a second portion which are alternately repeated; allocating a part of the first transmission cycle portion to each of a plurality of network entities employing the shared transmission medium; and allocating parts of the second transmission cycle portion as available to network entities employing the shared transmission medium based on primacy of requests for access to the shared transmission medium. 2. The method of claim 1, wherein the step of defining a transmission cycle having a first portion and a second portion which are alternately repeated further comprises: defining an adaptive time-division multiplexing transmission cycle portion and a residual transmission cycle portion. 3. The method of claim 1, wherein the step of allocating a part of the first transmission cycle portion to each of a plurality of network entities employing the shared transmission medium further comprises: allocating a logical link channel within the first transmission cycle portion to each network entity employing the shared transmission medium and participating in a communication protocol apportioning the first transmission cycle portion among all participating network entities in an ordered sequence of participating network entities. 4. The method of claim 1, wherein the step of allocating a part of the first transmission cycle portion to each of a plurality of network entities employing the shared transmission medium further comprises: allocating zero or more data payload channels within the first transmission cycle portion to each network entity employing the shared transmission medium and participating in a communication protocol apportioning the first transmission cycle portion among all participating network entities. 5. The method of claim 4, wherein the step of allocating zero or more data payload channels within the first transmission cycle portion to each network entity employing the shared transmission medium and participating in a communication protocol apportioning the first transmission cycle portion among all participating network entities further comprises: allocating data payload channels to each participating network entity based on loading conditions. 6. The method of claim 1, wherein the step of allocating a part of the first transmission cycle portion to each of a plurality of network entities employing the shared transmission medium further comprises: allocating parts of the first transmission cycle portion to each of a subset of network entities employing the shared transmission medium without allocating any part of the first transmission cycle portion to network entities employing the shared transmission medium without participating in the communication protocol. 7. The method of claim 1, wherein the step of allocating parts of the second transmission cycle portion as available to network entities employing the shared transmission medium based on primacy of requests for access to the shared transmission medium further comprises: allocating access to the shared transmission medium to network entities employing the shared transmission medium as requested with network entities backing off upon collision detection. 8. The method of claim 7, wherein the step of allocating parts of the second transmission cycle portion as available to network entities employing the shared transmission medium based on primacy of requests for access to the shared transmission medium further comprises: allocating access to the shared transmission medium during the second transmission cycle portion in compliance with the IEEE 802.3 to any network entity regardless of whether that network entity participates in a communication protocol apportioning the first transmission cycle portion among all participating network entities. 9. The method of claim 1, wherein the step of allocating parts of the second transmission cycle portion as available to network entities employing the shared transmission medium based on primacy of requests for access to the shared transmission medium further comprises: allocating access to the shared transmission medium to IEEE 802.3 compliant network entities. 10. A communication structure, comprising: a device capable of being selectively coupled to a shared medium and transmitting on the shared medium; and a communication protocol governing transmission on the shared medium by the device, the communication protocol: defining first and second transmission cycles which are alternately repeated; allocating portions of the first transmission cycle to the device and to each other device coupled to the shared medium and participating in the communication protocol for transmission on the shared medium; and allocating portions of the second transmission cycle based on primacy of requests to any device coupled to the shared medium and requesting access to the shared medium. 11. The communication structure of claim 10, further comprising: the shared medium; and at least one other device in addition to the device connected to the shared medium and participating in the communication protocol for transmissions on the shared medium. 12. The communication structure of claim 11, further comprising: at least one device connected to the shared medium and not participating in the communication protocol. 13. The communication structure of claim 10, wherein the device is a data processing system. 14. The communication structure of claim 10, wherein the device is a telephone. 15. The communication structure of claim 10, wherein the device is a data processing system and further comprising: a plurality of other devices, each selected from the group consisting of a data processing system and a telephone, each connected to the shared medium, and each participating in the communication protocol for transmissions on the shared medium; and at least one device connected to the shared medium and not participating in the communication protocol. 16. A computer program product within a computer usable medium, comprising: instructions for detecting a first transmission cycle on a shared medium; instructions, responsive to detection of the first transmission cycle on the shared medium, for joining a communication protocol allocating portions of transmission time on the shared medium during the first transmission cycle to each entity participating in the communications protocol; instructions for attempting to transmit during a second transmission cycle following the first transmission cycle upon detecting the shared medium to be idle; and instructions for backing off upon detection of a collision while attempting to transmit during the second transmission cycle. 17. The computer program product of claim 16, wherein the instructions for detecting a first transmission cycle on a shared medium further comprise: instructions for detecting a logical link layer data frame being transmitted on the shared medium and identifying a number of entities participating in the communication protocol. 18. The computer program product of claim 17, wherein the instructions for joining a communication protocol allocating portions of transmission time on the shared medium during the first transmission cycle to each entity participating in the communications protocol further comprise: instructions for assuming an identifier one greater than the number of entitied participating in the communication protocol. 19. The computer program product of claim 17, wherein the instructions for attempting to transmit during a second transmission cycle following the first transmission cycle upon detecting the shared medium to be idle further comprise: instructions for attempting an IEEE 802.3 compliant transmission during the second transmission cycle. 20. The computer program product of claim 17, further comprising: instructions for monitoring the shared medium for repetition of the first and second transmission cycles; instructions for transmitting a logical link layer data frame identifying payload data frame requirements during each repetition of the first transmission cycle; and instructions for attempting IEEE 802.3 compliant transmission, as needed, during each repetition of the second transmission cycle.
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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to communication between multiple devices over a single, shared transmission medium, and more specifically to employing an adaptive medium access control protocol together with a corresponding logical link control protocol supporting adaptive channel allocation to improve device communication over a shared transmission medium. 2. Description of the Prior Art Several access control methodologies exist for transmission on multi-access channels within a single transmission medium. Token ring and token bus schemes control access to the transmission medium in an orderly fashion designed to maximize bandwidth utilization and to maintain fairness (priorities) and determinism. Token ring and token bus schemes may be viewed as forms of multiplexing (MUXing), which may be loosely defined as combining two or more information channels onto a common transmission medium. Based on the premise that a transmission medium's speed and capacity far exceed a single user's requirements on any end of the communication medium, and the logical conclusion that several transmitting entities may be able to utilize the same transmission medium, multiplexing typically divides the medium transmission time into “timeslots”. Each timeslot is then uniquely assigned to a single transmitting entity, which owns the medium for the full duration of the timeslot and may transmit on the medium only during that assigned portion of time, and is the only transmitting entity permitted to transmit during that assigned portion of time. Time division multiplexing (TDM) thus achieves shared access to a single transmission medium by defined division of transmission time among the transmitting entities. In environments where usage requirements of transmitting entities may vary significantly at run time, statistical time division multiplexing (STDM), in which timeslot duration is not predetermined or fixed but instead varies at run time, may alternatively be employed. Ethernet-type medium access control schemes, on the other hand, generally allow a network element to transmit at will on the transmission medium. While non-deterministic in nature, this system possesses several attractive characteristics, including simplicity, support for dynamic changes in network element population, autonomous network element operation, low transmission latency at low utilization levels, and acceptable throughput under average loading conditions. Drawbacks of Ethernet include degradation of throughput under heavy traffic loading, non-determinism, and absence of priority assurance. Ethernet throughput rates are typically in the range of 20% to 50% depending on the specific implementation, and drop drastically from those levels when the transmission medium is heavily loaded. Current Ethernet transmission medium access control utilizes the truncated binary exponential back-off algorithm, a simple algorithm by which a transmission controller chip may adapt access to the medium according to the medium loading condition. The basic outcome of the algorithm is minimal latency and acceptable throughput and utilization under light loading conditions, with increased latency and acceptable throughput and bandwidth utilization as traffic increases towards heavy traffic conditions. It would be desirable, therefore, to provide a shared medium control access methodology which exploits the benefits of Ethernet-type systems while providing some levels of determinism, priority, and sustained throughput efficiency with increasing traffic loads. It would also be advantageous for the methodology to conduct adaptive channel allocation of transmission jobs into virtual channels on the medium. SUMMARY OF THE INVENTION A hybrid transmission cycle (HTC) unit of bandwidth on a shared transmission medium is defined to include an adaptive, time division multiplexing transmission cycle (ATTC), which is allocated in portions sequentially among all participating network entities, and a residual transmission cycle (RTC), which is allocated in portions, as available, to the first network entity requesting access to the shared medium during each particular portion. The ratio of logical link virtual channels, or D-Channels, to data payload virtual channels, or B-Channels, within the ATTC is adaptive depending on loading conditions. Based on transmission profiles transmitted on the D-Channels during the ATTC, each network entity determines how many B-Channels it will utilize within the current HTC. This calculation may be based on any decision network, such as a decision network modelling the transmission medium as a marketplace and employing microeconomic principles to determine utilization. The ratio of the duration of the ATTC segment to the duration of the RTC segment is also adaptive depending on loading conditions, to prevent unacceptable latency for legacy network entities employing the shared transmission medium. During the RTC, utilization of the shared medium preferably reverts to IEEE 802.3 compliant CSMA/CD transmission, including transmissions by HTC-compliant network entities. BRIEF DESCRIPTION OF THE DRAWINGS The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, and further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: FIG. 1 depicts a block diagram of a network in which a preferred embodiment of the present invention may be implemented; FIG. 2 is a system architecture diagram for a network element in accordance with a preferred embodiment of the present invention; FIGS. 3A-3C depict a hybrid transmission cycle employed for transmission on a shared medium in accordance with a preferred embodiment of the present invention; FIG. 4 is a state diagram for the medium access control (MAC) transmission protocol within a network entity in accordance with a preferred embodiment of the present invention; FIG. 5 depicts a protocol hierarchy diagram for adaptive channel allocation in accordance with a preferred embodiment of the present invention; FIG. 6 is a high level flow chart summarizing a process of adaptive channel allocation in accordance with a preferred embodiment of the present invention; FIG. 7 depicts a decision network for adaptive channel allocation in accordance with an exemplary embodiment of the present invention; and FIGS. 8A-8K are plots from simulations of a shared transmission medium utilizing standard 802.3 compliant and/or HTC-compliant network communications under various conditions and combinations of network elements. DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to the figures, and in particular with reference to FIG. 1, a block diagram of a network in which a preferred embodiment of the present invention may be implemented is depicted. Network 102 includes a plurality of network entities 104a-104n coupled to a shared transmission medium 106. Network entities 104a-104n may be data processing systems including network interface cards or adapters, or may be communications devices such as telephone handsets or the like. Shared transmission medium 106 may be coaxial cable, RJ-11 wiring, line-of-sight radio frequency (RF) spectrum, or some similar wired or wireless transmission medium. While not limited, the number of network entities 104a-104n which share a single network transmission medium 106, should be reasonable. An excessive number (e.g., 500 or more) of network entities 104a-104n within a single network 102 will, even when they have nothing to transmit, waste significant bandwidth in the present invention. Referring to FIG. 2, which is intended to be considered in conjunction with FIG. 1, a system architecture diagram for a network element in accordance with a preferred embodiment of the present invention is illustrated. At the physical layer 202, network entity 104 includes an Ethernet controller chip 204 which interfaces directly with the Ethernet transceiver 206 and the shared transmission medium (e.g., wire) 106. Ethernet controller chip 204 generally conforms to the Ethernet standard, with the exception of differences specifically noted below, and is controlled by an Ethernet software driver 208, which interfaces with controller chip 204 by Direct Memory Access (DMA) and interrupt processing, a standard technique for implementing Ethernet controllers and corresponding driver software. Ethernet controller chip 204 and Ethernet software driver 208 utilize the IEEE 802.3 Carrier Sense Multiple Access with Collision Detect (CSMA/CD) mechanism for controlling access to shared transmission medium 106. Any transmission medium employed by several transmitting entities requires a method of controlling access to the shared medium to ensure that only one transmitting entity transmits on the medium at a given time in order to prevent interference between competing transmissions. “Contention” refers to the circumstance in which two or more transmitting entities seek access to the shared medium at the same time. In general, contention does not necessarily implicate “collision,” or interference of competing signals on the shared physical medium, but collision does indicate contention. CSMA/CD is a contention resolution protocol which utilizes collision detection to infer contention, and is employed by Ethernet and the present invention to control access to the shared transmission medium. Ethernet controller 204 obeys the CSMA/CD protocol transmission state machine which, before transmitting, monitors the carrier sense and collision signals on shared transmission medium 106 for network activity. If another network entity (also referred to as “node”) is currently transmitting on the shared medium 106, the controller 204 defers transmission until the network is quiet, and then transmits. Once the Ethernet controller 204 detects that the shared medium 106 is idle, it begins transmission. If a collision is detected because another controller had also detected the medium to be idle and began transmission at the same time, both controllers will abort the transmission. When the Ethernet controller 204 experiences a collision during a transmission, the controller 204 switches from transmitting data to transmitting a 4-byte JAM pattern (4-bytes, all logical 1's) before ceasing transmission. The controller 204 then randomly selects a time duration to back-off before attempting to transmit again. That is, the controller 204 waits a random number of slot times (51.2 μs) determined by the “truncated binary exponential back-off algorithm” before reattempting another transmission. The first time the controller 204 detects a collision, the controller will randomly select a back-off time duration rt, where t is the slot time and r is a random integer selected from the interval 0≦r≦21. If, after the selected back-off duration t has expired, the controller 204 still encounters a collision, then the controller 204 selects a new random back-off duration slot time multiple from the interval 0≦r≦22. The process continues expanding the range of selection by increasing the exponent of the upper limit for the selected slot time multiple for each collision detected. Under the current standard specified in IEEE 802.3, the exponent may reach a maximum of 10. Thus, for conventional Ethernet implementations, the number of slot times which a controller delays before the nth retransmission is chosen to be a random integer r in the range of 0≦r≦2k, where k=min(n, 10). In the present invention, however, the upper limit of the exponent k employed in selecting a back-off duration, and whether or not to employ a backoff algortihm, is determined by controller 204. This is a violation of the IEEE 802.3 standard requirement of an upper limit of 10, which is typically hard coded in contemporary Ethernet controllers. In the preferred embodiment, the value of exponent k is configurable, and is set in accordance with standard 802.3 requirements only during the RTC (Residual Transmission Cycle). The exponent k value is set to a maximum of 6 when the ethernet controller is attempting transmission of a Join D-Channel frame, a value selected to accommodate a worst case scenario when 26 (64) network entities are attempting simultaneous Join D-Channel frame transmissions. Otherwise, the ethernet controller does not back off and immediately retransmits during the ATTC phase. The paramount benefit of conventional Ethernet controllers which employ a maximum value of 10 for the exponent k within the back-off algorithm is that collisions occurring under low traffic loads will be reattempted shortly after the collision occurs since the back-off duration is initially selected from a shorter interval t, e.g., 0≦t≦23(51.2 μs) for the first three collisions. As the number of consecutive collisions (presumably resulting from higher traffic loads) for any particular transmission attempt increases, the back-off duration is selected from a wider range, thus delaying transmission attempts and increasing latency. Latency may be defined as the amount of time which a transmitter entity must wait before gaining access to a shared transmission medium. In an ordered access control scheme such as token ring, latency increases predictably with the number of stations seeking access to the shared transmission medium. In conventional Ethernet implementations, latency increase with traffic load is less predictable. However, by selecting the back-off duration from wider and wider ranges after each consecutive collision for a given transmission attempt, the conventional Ethernet controller effectively achieves a wider spread of transmission attempts as the shared medium becomes more heavily loaded. The result is automatic and deliberate increase in latency as the number of consecutive collisions increases. The present invention effectively neuters the Ethernet truncated binary back-off algorithm during the ATTC and renders the controller 204 aggressive in the event of collision detection. During the RTC transmission sub-cycle when a new HTC-compliant network entity is attempting transmission of a Join D-Channel, the number of slot times which controller 204 delays before the nth retry of a transmission attempt is selected, for example, from the range of 0≦r≦2k, where k=min(n, 6). During the ATTC transmission sub-cycle, the controller 204 does not back off; after sixteen transmission attempts, however, the controller 204 will abort transmission of the packet and report an “excessive collisions” error message to driver 208. Software driver 208 receives data frames from medium access control (MAC) protocol layer 210. Unlike typical Ethernet driver operation, where data frames are submitted to the driver in any quantity, the number of frames submitted to driver 208 for transmission is controlled by MAC layer 210. While in normal Ethernet driver implementations the layer two entity submits all of the frames which it has to transmit to the driver at once, and the driver may, in turn, buffer several or all of these frames in the DMA area before issuing a transmit command to the Ethernet controller chip, in the present invention the MAC layer 210 controls when and how many frames are submitted to driver 208, although driver 208 may still buffer frames. MAC layer 210 provides intelligent control over when and what is transmitted on shared medium 106, a feature made possible by advances in processor speeds and memory availability. MAC layer 210 employs elastic time division multiplexing (TDM) over an asynchronous multi access channel. Shared transmission medium 106 is perceived by network entities 104a-104n as composed of many virtual channels which, unlike most TDM schemes, are elastic in both number and size, either of which may increase or decrease at run time. On top of MAC layer 210, an adaptive channel allocation protocol (ACAP) layer 212 is implemented as a logical link control (LLC) protocol. ACAP layer 212 serves as a decision theoretic agent utilizing a decision network (influence diagram) 214 to process current network loading conditions and, after determining allocation requirements and optimizing the decision network, adapting the bearer channel transmission profile by changing its transmission concentration ratio and its transmission cycle component ratios. ACAP layer 212 issues instructions in the form of primitives to MAC layer 210 to execute the results of the decision network optimization. ACAP agent 212 modifies these two values (TCR and ATTC:RTC ratio) to maximize transmission success within current network conditions. User applications 216 submit frames for transmission, together with an optional transmission profile, to ACAP agent 212 via an ACAP application program interface (API) 218. ACAP API 218 is a set of routines which access the requisite methods within ACAP agent 212, preferably maintained to a minimum of “transmit” and “receive” routines, and an optional “submit” routine providing a suggestion mechanism for user applications 216 to communicate respective future data transmission requirements. With reference now to FIGS. 3A through 3C, a hybrid transmission cycle employed for transmission on a shared medium in accordance with a preferred embodiment of the present invention is depicted. FIG. 3A is a hybrid transmission cycle (HTC) 302, the format by which network entities perceive the shared transmission medium. The medium is available for transmission only to the extent that virtual channels (VC) within the HTC 302 are idle. HTC 302 is a unit of bandwidth which is variable in size and decomposes into several virtual channels of varying sizes. The bandwidth sum of the virtual channels contained in an HTC 302 equals the total bandwidth of the HTC 302. Transmission by a network entity during an HTC 302 may only occur at the boundary of a virtual channel. Virtual channels 304 are of two types: data link channels (“D-Channels”) 306 and data bearer channels (“B-Channels”) 308. D-Channels 306 serve as control and signaling channels while B-Channels 308 are payload data channels. Negotiation for B-Channel acquisition and relinquishing by a particular network entity is conducted utilizing a protocol over the D-Channel for that network entity. Thus, HTC 302 is a repeating format of virtual transmission channels which may be assigned differently from one cycle to the next based on control information exchanged over the D-Channels. Each HTC 302 includes an adaptive TDM transmission cycle (ATTC) 310 followed by a residual transmission cycle (RTC) 312. Each ATTC 310 includes many virtual channels, and begins with one D-Channel followed by zero or more B-Channels, followed by a second D-Channel and zero of more B-Channels, and so on. D-Channels are dedicated to the exchange of control information, and each network element on the shared transmission medium will have a reserved D-Channel in the ATTC 310 of each HTC 302. A network entity wishing to retain ownership of its B-Channel position within the ATTC 310 must mandatorily transmit a transmission profile on its D-Channel. A network entity which fails to transmit a transmission profile on its assigned D-Channel is deemed to no longer exist, and its D-Channel slot is assumed by the next higher network entity. A shift left operation is performed on subsequent D-Channel slots such that the resulting ATTC 310 includes sequentially incrementing D-Channel numbers. FIGS. 3B and 3C depict the ATTC 310 and the RTC 312, respectively, in greater detail. For the purposes of describing the invention, the designation “D1” is employed to indicate D-Channel 1, “D2” to identify D-Channel 2, and so on. The designation “DnX” indicates the nth D-Channel of the transmission cycle, and also indicates that the network entity owning that virtual channel does not wish to transmit any B-Channel data at this time. The designation “DnF” identifies the nth D-Channel in the cycle as the final D-Channel for the cycle. A designation of “DnXF” is therefore possible. The designation of “B1” identifies the first B-Channel for a given network entity, while “BnF” indicates that the identified B-Channel is the final B-Channel for the network entity owning the transmission sub-cycle (identified by 310a, 310b, and 310n in FIG. 3). B-Channel identifiers do not include the sub-cycle identifier (e.g., as belonging to network entity “3”) since that may be inferred from the context of the transmission time. The designation “D1R” indicates the beginning of the RTC 312, and that network entity “1” is transmitting the synchronization signal described in further detail below. The designation “D3RF” identifies the final synchronization signal in the RTC 312 portion of HTC 302. Limitations are imposed in the present invention on both ATTC 310 and RTC 312. The maximum transmission concentration ratio (MTCR) is the ratio of B-Channel to D-Channel quantities. For instance, an MTCR of 50:1 means that every D-Channel may be immediately followed by a maximum of up to fifty B-Channels. The MTCR ensures a certain level of granularity in the transmission cycle which has acceptable performance characteristics. It would be inefficient, for example, to have 10 D-Channels (corresponding to 10 network entities) and only 10 B-Channels, at most, per D-channel, a granularity which could result in half the bandwidth being allocated to data link signaling and half allocation to payload traffic, a poor allocation scheme. It should be noted that the MTCR is a fixed ratio serving as a limit for a transmission concentration ratio (TCR), which is the actual concentration ratio employed by a network entity. Although initially set to 50 (the limit specified by MTCR), the TCR is adaptive to network loading conditions and other factors. Run time adaption of the TCR is fundamental to adaptive transmission. The MTCR ensures that a network entity assigned a late sub-cycle in the HTC 302 is not excessively delayed in gaining access to the shared medium. Additionally, the MAC protocol is capable of coexisting with conventional 802.3 Ethernet implementations (normal 802.3 Ethernet transmission is conducted during the RTC 312). It is necessary, therefore, that the RTC 312 appear quickly enough within the HTC 302 to avoid inducing unacceptable latency in conventional 802.3 Ethernet implementations sharing the same transmission medium. The MTCR places a maximum limit on duration of the ATTC 310. The MTCR also ensures correct acquisition of a sub-cycle by new network entities, and specifies the maximum number of network entities permitted on the network, which may be obtained from: max ( NetworkEntities ) = Medium Data Rate ( 1 + MTCR ) * 1518 where the medium data rate is specified in bytes per second and 1,518 is the maximum byte length of a conventional 802.3 Ethernet frame, while (1+MTCR) specifies one D-Channel and MTCR B-Channels per sub-cycle. The MTCR is a preconfigured quantity, much like the maximum transmission unit (MTU) and minimum frame length employed by conventional 802.3 Ethernet implementations. However, the MTCR serves as a boundary value, with the actual TCR fluctuating at run time. The open 802.3 transmission time within the RTC 312 should be set to a ratio of the pre-configured MTCR; for an open transmission time/MTCR ratio of 1 and for an MTCR of 50, the open 802.3 transmission time will be 50 MTU transmission time. The RTC 312 should also be required to have an overall minimum length of one MTCR. No length restriction need be imposed on the length of a B-Channel save the standard 802.3 minimum frame length of 64 bytes and the maximum of 1,518 bytes. A D-Channel within the ATTC 310 is identified by an integer number, with the first D-Channel having the identifier 1 and the second D-Channel having the identifier 2, etc. This identifier is also assigned to the network entity which acquires that D-Channel. For instance, when the shared medium is idle, as in the case of an inactive network, a network element connecting to the medium will enter a listen mode and attempt to detect D-Channel transmissions. If no D-Channel is detected, the network entity assumes itself to be the first to appear on the identifier and assigns itself an identifier of 1, claiming the first sub-cycle within the ATTC 310. Thereafter the network entity initiates an HTC 302 by transmitting a D-Channel transmission profile. Other network entities may or may not appear. If not, the sole network entity transmitting according to the adaptive MAC protocol of the present invention will result in an HTC 302 having only one transmission sub-cycle within the ATTC 310, with one D-Channel and 50 B-Channel under a default MTCR of 50 and a RTC 312 of 50 MTU, assuming a 1:1 ratio of ATTC 310 to RTC 312. HTC 302 is a repetitive transmission lifetime consisting of one or more transmission sub-cycles within the ATTC 310 followed by the RTC 312. A sub-cycle in an ATTC 310 belongs to a particular network entity, and at the beginning of each sub-cycle a network element will declare its B-Channel allocation requirements and assignments over the D-Channel, then proceed to utilize the B-Channels accordingly. A sub-cycle thus consists of only one D-Channel and zero or more B-Channels. To extract the maximum possible benefit of the transmission profile exchange over the D-Channel, the B-Channels should be significantly greater in number and bandwidth that the D-Channels. On the other hand, the concentration ratio should not be excessive such that network entities wishing to change an allocation scheme are prevented from doing so within a reasonable amount of time. D-Channels and B-Channels are interleaved over the full ATTC 310, each interleaved set consisting of one D-Channel and zero or more B-Channels all belonging to a particular network entity. Such interleaving improves latency for the network entities, allowing a network entity to transmit immediately after performing the transmission profile broadcast over its D-Channel and permitting other network entities to perform computation of current network conditions and belief updating in corresponding decision networks. Transmission priorities, an important part of the adaptive MAC protocol of the present invention, are configurable by software. When priorities are not otherwise assigned to network entities, each network entity will have a priority equivalent to its D-Channel sub-cycle number within the ATTC 310, with 1 being the highest priority. Network entities are assigned a unique integer identification number, starting from 1, when joining the transmission protocol, an assignment made by the network entity itself after observing what other network entities are transmitting on the medium over the D-Channel. The network entity identifier specifies the sub-cycle within the ATTC 310 which is owned by the respective network entity. The run time network-entity identifier also serves as the network entity priority in the event that no configuration of priority is performed for the network entity. Under this default system, a network entity identifier value of 1 indicates the highest priority network entity and also means that the corresponding network entity was the first, or earliest, to appear on the medium. Network entity priority is computed as follows: R i = 1 id where Ri is the priority and “id” is the network entity identifier. When a network entity wishes to join the medium for the first time, after power up, for example, that network entity listens for D-Channel transmissions on the shared medium. Upon detecting a D-Channel transmission, the highest currently-assigned network entity identifier may be read from the transmission profile. The network entity then assigns itself the next higher network entity identifier, as described below. the network entity with an identifier value of 1 transmits on D-Channel D1, the network entity with an identifier value of 2 transmits on D-Channel D2, etc. Additionally, the B-Channels immediately follow the D-Channel owned by a network entity. As a result, the first transmission sub-cycle within the ATTC 310 is owned by network entity 1, the second sub-cycle is owned by network entity 2, and so on. Since the adaptive MAC protocol of the present invention is intended to fit seamlessly into an existing deployment of conventional 802.3 Ethernet MAC, the RTC 312 is included, providing a duration of time occurring immediately following the ATTC 310 during which normal 802.3 Ethernet CSMA/CD compliant transmission occurs. Thus, during the RTC 312, the shared medium reverts to be a free-for-all just as in conventional 802.3 Ethernet implementations, and network entities employing the adaptive MAC protocol of the present invention also revert to this mode for the duration of the RTC 312. Network entities employing the adaptive MAC protocol of the present invention utilize a non-back off transmission mode during the ATTC. The adaptive MAC layer of network entities in accordance with the present invention implements the 802.3 Ethernet transmission state machine during the RTC, as described in further detail below, giving the illusion of a compliant 802.3 chipset. Every network element on the shared medium will have a run-time designated D-Channel on which that network element is obligated to transmit. This D-Channel is employed to carry transmission profile information constructed by the network entity. At the beginning of every transmission sub-cycle within the ATTC 310, the network entity assigned to that sub-cycle constructs and transmits a transmission profile over the D-Channel, which is therefore a datalink or control information carrier over which network entities exchange transmission profile information. The transmission profile content is employed by each network entity to inform the network population of its B-Channel allocation, mainly represented by two quantities: its current TCR and its ATTC:RTC ratio. Every transmission on a virtual channel is tagged with the identity of the virtual channel in order to ensure continuous global synchronization of participating network entities. Therefore, Ethernet controller chipsets within the compliant network entities should be configured either to operate in the promiscuous mode or to accept multicast MAC addresses. TABLE I Type Name Count Description byte SourceMacAddr 6 Sender's physical address byte DestinationMacAddr 6 Multicast destination address, implementation dependent word Length/Type 1 802.3 length, or Ethernet type, 0x7FF (2047) word FrameId 1 Identifies the global D-Channel id, and the global network element id word TotalDChannelNum 1 Total number of D-Channels known to this network entity word MessageGenRate 1 Message generation rate B-ChannelProfile Profile 1 Transmission requirements of network entity and status of ATTC B-Channels perceived by network entity (TCR). Count may be in the range of 0 . . . TotalB- ChannelBandwidth Table I describes the format of a D-Channel frame in accordance with the present invention. The D-Channel frame is distinguished from conventional 802.3 Ethernet frames by the length (or “Type”) field, common to both frame formats, which may contain a type identifier value, currently-unassigned (see RFC-1700), of decimal 2,047, hexadecimal 7FF. The FrameId number is placed after the type field in the D-Channel frame format, containing an encoded value indicating the D-Channel identification. After the FrameId field, the Transmission Profile is placed in the payload data area. The sequence and structure of the FrameId and Transmission Profile fields is described in Tables II and III, respectively. TABLE II Bit (base zero) Valid Values Description 15 (MSB) 1 Final D-Channel 0 Non-final D-Channel 14 1 Synch D-Channel 0 Non-synch D-Channel 0 . . . 13 1 . . . 16383 D-Channel Id (channel id may not be zero) TABLE III Type Name Count Description word TCR 1 0 . . . 50 Transmission Concentration Ratio for this network entity word RtcRatio 1 ATTC:RTC ratio for this network entity The most significant bit of the FrameId field is asserted if the D-Channel is a final D-Channel, with the second most significant bit being asserted if the D-Channel is a sync D-Channel transmitted during an RTC. The remaining 14 bits contain a unique D-Channel identifier, which is also the unique network entity identifier. Since zero is not a permissible identifier, the format supports 214−1=16,383 unique identifiers. Like the D-Channel, the B-Channel (the data bearer channel) is up to MTU bytes in size, and therefore for most implementations will be up to 1,518 bytes in length. The B-Channel is identified within the sub-cycle during which it is being transmitted, and will therefore be uniquely identified since sub-cycles are unique. B-Channels appearing at the end of a transmission sub-cycle are also identified as final B-Channels, but there are no residual B-Channels (i.e., B-Channels transmitted during an RTC) since transmission during the RTC is fully compliant, standard 802.3 Ethernet CSMA/CD transmission. B-Channels are owned by and indirectly exchanged among network entities. A newly arrived network entity is initially assigned 50 (MTCR) B-Channels along with a D-Channel and network entity identifier at the time it joins the network. In other words, a new network entity is initially assigned a full transmission sub-cycle worth of bandwidth. The B-Channel frame format, described in Table IV, is also identified by the Length field of conventional 802.3 Ethernet frames, with a type id value (currently unassigned) of decimal 2,046 (Hexadecimal 7FE) preferably being selected. The B-Channel is essentially an 802.3 Ethernet frame with source and destination MAC addresses. Since the destination MAC address is not a multicast address as in the D-Channel's case, all network entity driver software must be initialized either to operate in the promiscuous mode or to enable multicast reception so that B-Channel transmission may be visible to those entities. This is important to maintain synchronization. The FrameId field indicates the physical space in which the B-Channel is being transmitted, an important distinction from the actual owner of the B-Channel. TABLE IV Type Name Count Description byte SourceMacAddr 6 Sender's physical address byte DestinationMacAddr 6 Unique destination address word Length/Type 1 802.3 length, or Ethernet type, 0x7FE (2046) word FrameId 1 Identifies the global B-Channel id which identifies the current owner of the B-Channel. (Note that this B-Channel may be “borrowed” but will still bear the owner's id). byte Data 1497 Payload data TABLE V Bit (base zero) Valid Values Description 31 (MSB) 1 Final B-Channel 0 Non-final B-Channel 16 . . . 30 (15 bits) 1 . . . 32767 D-Channel id (or network entity currently transmitting on this B-Channel) 0 . . . 15 (16 bits) 1 . . . 65535 B-Channel id within this transmission sub-cycle (channel id may not be zero) Within the FrameId sequence and structure, described in Table V, the most significant bit is asserted if the B-Channel is a final B-Channel. The next 15 bits indicate the D-Channel or transmission sub-cycle to which the B-Channel belongs, with the remaining 16 bits serving as a B-Channel identification number for 216−1=65,535 unique B-Channel identifiers. Upon connecting to the network, a network entity enters a mode in which it attempts to ascertain the status of on-going communication. Essentially, the network entity will listen for a D-Channel transmission, for a period of 50 (MTCR) MTUs in the event that the default MTCR is 50. If a D-Channel transmission is detected, then the network entity will conclude that it is not the first network entity to appear on this medium and that it must determine the global network entity identifier which it may assume. This is the lowest available network entity identifier, which is easily determined since the transmission profile allows a new network entity to determine the highest assigned D-Channel number and may then assign itself the maximum D-Channel number assigned plus 1. As soon as the open 802.3 transmission time in the RTC begins, the new network entity will make itself known to the remaining network entities by transmitting a “Join-D-Channel” frame, indicating the network identifier which it has assigned itself. Since a collision may occur if another network entity happened to join the network during the same HTC, so this contention is resolved by implementing a back-off algorithm which is in effect during the RTC. The back-off algorithm selected differs from the standard 802.3 CSMA/CD contention resolution to gain access to the medium, since it is desirable for the network entity to access the medium in a more persistent manner. Several timing requirements are imposed on the HTC in order to make detection and membership possible by the network entities. Every network entity transmitting a transmission profile on the D-Channel must include the total number of network entities known to be on the network, which is also the total number of D-Channels in the ATC. When the last D-Channel of the ATC is complete, all network entities transition to the RTC phase in which new network entities may join the network. When a new member network entity makes its presence known by transmitting a D-Channel during the RTC phase, it continues to utilize the RTC on an 802.3 CSMA/CD basis and does not get to transmit a sync D-Channel until the next RTC. A network entity may also disappear from the network, a situation handled by timing. At the end of every D-Channel transmission, every network entity starts a D-Channel wait timer in order to determine whether the network entity which owns the next D-Channel is still active. If the timer expires with no transmission, the network entity which owns the next subsequent D-Channel assumes the newly disappeared network entity's identifier and will begin transmission of the D-Channel sub-cycle. The transmission wealth of the newly disappeared network entity is not assumed by any particular network entity, but is inherently allocated to the network as a whole. Dynamic D-Channel identifier reassignment requires that a shift operation be performed on the D-Channel identifier assignments. If the network entity with identifier five disappears, then network entity six assumes the identifier five, network entity seven assumes the identifier six, etc. If an inadvertent condition occurs whereby two or more network entities assume the identifier of a disappeared network entity, then the first network entity to capture the medium assumes the identifier of the disappeared network entity while the remaining network entities are bounced out to the RTC join mechanism. Referring to FIG. 4, a state diagram for the MAC transmission protocol within a network entity in accordance with a preferred embodiment of the present invention is illustrated. The diagram shown illustrates a happy day scenario, showing the general flow of the transmission cycle detection mechanism as well as transmission within a cycle and the startup scenario with acquisition of an identifier by a network entity, but not including error conditions. Upon startup, an network entity enters the listen state 402, in which detection of an HTC is attempted utilizing a timeout value of at least one full ATTC to ensure that sufficient time is given to account for the situation in which an HTC exists but the network entity which was supposed to be transmitting suddenly drops out of the transmission cycle. For this reason, the maximum number of network entities in the MAC protocol of the present invention is also computed to conform to the medium data rate. While in listen state 402, the network entity attempts to identify D-Channel or B-Channel transmissions, which may be easily performed by examining the Ethernet type field specified to be decimal 2,047 for a D-Channel and decimal 2,046 for a B-Channel. If the network entity detects a frame of either the D-Channel or B-Channel type, then it transitions to the read D-Channel state 404. If, however, a timeout occurs without detection of a D-Channel or B-Channel transmission, then the network entity transitions instead to transmit D-Channel state 406. In read D-Channel state 404, the network entity attempts to synchronize on the full HTC, meaning the network entity attempts to synchronize with the ATTC phase by identifying the D-Channel transmission sequence and reading the profiles being transmitted on the D-Channels. The network entity is informed of the current status of the network by the D-Channels transmitted by other network entities and, upon failure to synchronize onto the ATTC within a timeout period, transitions back to listen state 402. In transmit-D-Channel state 406, the network entity formulates and transmits a D-Channel transmission profile, thus starting a transmission sub-cycle within the ATTC. If the network entity has entered the transmit D-Channel state 406 from the listen state 402, the D-Channel transmission would be the beginning of a completely new ATTC. Otherwise, the D-Channel transmission during the transmit D-Channel state 406 is merely a normal in-sequence sub-cycle transmission. When in the read D-Channel state 404, the network entity monitors the ATTC phase transmission and, upon detection of a final D-Channel transmission, transitions to the assign identifier state 408. In the assign identifier state 408, the network entity assigns itself an identifier which is one greater than the maximum D-Channel identifier currently in the ATTC, and then awaits the final B-Channel transmission of the final sub-cycle for the current ATTC (a description of the usage of timers for this purpose, which will be understood by those in the art, is omitted for brevity). Upon detecting transmission of the final B-Channel for the last sub-cycle within the detected ATTC, the network entity transitions to the transmit join D-Channel state 410. The network is now in the RTC phase and the network entity is ready to transmit a “join” D-Channel as described above to gain membership in the HTC. The ATTC is the interleaved transmission of one D-Channel followed by zero or more B-Channels, all originating from one network entity, then another D-Channel followed by zero or more B-Channels, all from a second network entity, and so forth. Thus, while the network is in the ATTC phase, the network entity may be in one of four possible states. In the transmit D-Channel state 406, the network entity has determined that it is now time to transmit its D-Channel frame, either because (1) no other participating network entity was detected transmitting on the shared medium or because (2) the network entity, having already gained membership and begun participating with other network entities in the HTC, detects completion of the transmission of the final B-Channel for the network entity having an identifier value which is one less than that of the subject network entity. In either case, the network entity formulates and transmits a D-Channel frame and, upon successful transmission of the D-Channel frame, transitions to the transmit B-Channel state 412. In the transmit B-Channel state 412, the network entity formulates and transmits payload data embedded within B-Channel frames. The network entity may transmit as many B-Channels as it physically owns, up to MTCR, but should conform to the declared TCR in the D-Channel and preferably may not exceed this limit. The protocol may not accommodate situations where a network entity violates these rules and exceeds either the physical B-Channel allocation or the declared TCR. If the network entity has no payload data to transmit, then it is obliged to transmit a D-Channel while in transmit D-Channel state 406 which indicated that no payload data (i.e., no B-Channels) are forthcoming, and transitions directly through transmit B-Channel state 412 to receive D-Channel state 414. However, if payload data is available for transmission, then the network entity transmits up to the number of physical B-Channels designated by the declared TCR in the D-Channel while in transmit B-Channel state 412. The network entity further ensures that the last B-Channel transmitted is of the type “final,” which provides the go-ahead indication to the next network entity whose turn it is to transmit. Upon completing transmission of the final B-Channel, the network entity transitions to the receive D-Channel state 414 in which the network entity awaits the D-Channel transmission by the next network entity. Not only the subject network entity is expecting and awaiting the D-Channel transmission by the next participating network entity, but all other participating network entities other than that whose turn it is to transmit are expecting and awaiting the D-Channel transmission. When a D-Channel transmission is detected by the network entity while in the receive D-Channel state 414, the network entity then transitions to receive B-Channel state 416, in which the network entity expects and awaits B-Channel transmissions which end with a final B-Channel. Usage of timers for these purposes in accordance with the known art is again omitted for simplicity. During the ATTC, the network entity alternates primarily between receive D-Channel state 414 and receive B-Channel state 416, except when its turn to transmit is reached, at which time it will transition to transmit D-Channel state 406 to or through transmit B-Channel state 412 and then, generally, back to receive D-Channel state 414 and receive B-Channel state 416. Generally, the network entity transitions out of the receive D-Channel and receive B-Channel pair of states 414 and 416 in two situations: First, if the network entity transmitting the B-Channels has an identifier one less that the identifier of the subject network entity and completes transmission of a final B-Channel, making it the subject network entity's turn to transmit a D-Channel, the network entity transitions to transmit D-Channel state 406 described earlier. Second, if a final B-Channel was received for the last sub-cycle within the ATTC (i.e., the last D-Channel transmitted was the final D-Channel for the ATTC), the network entity transitions to the transmit residual cycle D-Channel state 418. During the RTC, the participating network entities transmit sequential and periodic sync D-Channels, which serve to demarcate the progress of time in the RTC. New network entities desiring membership in the HTC transmit their join D-Channel frames during the open 802.3 transmission time, while in the transmit join D-Channel state 410, a deliberate violation of 802.3 CSMA/CD is conducted that is intended to ensure that the new network entity gains membership within the current RTC and does not have to wait until the next RTC. However, in the event that a collision occurs during the open 802.3 transmission time, the network entity backs off in a manner similar to, but not identical with, the 802.3 back-off algorithm. The back-off algorithm for joining the HTC should preferably be far more aggressive than the standard 802.3 back-off algorithm so as to ensure successful transmission of the join D-Channel frame by the new network entity. After successful transmission of a join D-Channel frame while in the transmit join D-Channel state 410, the network entity transitions to the transmit residual cycle D-Channel state 418, where it simply monitors the RTC progress and joins in the open 802.3 transmission method. During the next ATTC, the newly joined network entity will have an opportunity to utilize its newly acquired membership in the HTC. During the RTC which follows each ATTC, the adaptive MAC protocol of the present invention is relaxed and all network entities revert to normal 802.3 transmission. During this portion of the HTC, those network entities which are not participating in the HTC may transmit on the shared medium utilizing standard 802.3 transmission. A membership grace period, the duration of time when new HTC-compliant network entities are expected to assign themselves the next higher network entity identifier value and transmit a join D-Channel frame during the open 802.3 transmission sub-cycle, spans the RTC. Several new network entities may join the HTC during the membership grace period. If a collision occurs, the colliding network entities will utilize the back-off algorithm implemented within the MAC layer and try again at different times within the current grace period. The back-off algorithm employed in resolving collisions of join D-Channel frames should be sufficiently aggressive to allow all new network entities to join the HTC during the current grace period, even if multiple attempts are required. The RTC is similar in structure to the ATTC, but differs in that there is no logical control of access such as the adaptive MAC protocol. Access to the shared medium for portions (or transmission sub-cycles) of the RTC are granted, as available, to the first network entity requesting access during a specific transmission sub-cycle, with contention resolution conforming to standard 802.3 CSMA/CD, including the exponent k value. The only interference to gaining access during the RTC from HTC-compliant network entities is-the transmission of periodic synchronization D-Channels, or “sync D-Channels.” Compliant network entities are expected to be fairly well synchronized in their timer functions after having completed the ATTC, and synchronization during the RTC is relied upon to control the transition into and out of the RTC. The first sync D-Channel is transmitted by the compliant network entity having an identifier value of 1, with all other compliant network entities starting timers for the following 802.3 transmission sub-cycle. The duration of the 802.3 transmission sub-cycle will be proportional to an MTCR B-Channel transmission time (a multiple of the duration of 50 B-Channels if the default MTCR of 50 is utilized), and is determined by the ATTC:RTC ratio set within the decision network by the network entity transmitting the synch D-Channel. The network entity having the highest identifier value will transmit the final sync D-Channel, indicating that the next 802.3 transmission sub-cycle will be the final transmission period of the RTC and that, immediately following the TCR-based RTC duration, the network entity having the identifier value of 1 is expected to initiate a new ATTC by transmitting its D-Channel frame. Transmission of a Sync D-Channel is aggressive and is not subject to back off. The HTC network entity transmitting the Sync D-Channel will retransmit immediately upon collision detection and will not back off. Excessive collisions of the Sync D-Channel will cause loss of membership and reset to the Listen state. The scheme described allows network entities to disappear, or unexpectedly drop out, from the RTC. If a network entity does drop out, then the timers within all other network entities, which are initially set according to the ATTC:RTC declared over the D-Channel in the ATTC by the current owner of the RTC sub-cycle, will detect the drop-out and the next network entity following the missing network entity will assume its identity. A shift operation on all network entity identifiers above the identifier of the network entity which disappeared will be performed, similar to the drop-out scenarios which may happen during the ATTC. Since the HTC-compliant network entities are intended to coexist on the shared medium with standard 802.3 Ethernet network entities (that is, not every network entity connected to the network need be running the adaptive MAC protocol and ACAP stack of the present invention), collisions may occur with “rogue” (standard 802.3 only) network entities. A network entity detecting a collision while transmitting over the D-Channel or B-Channel during the ATTC does not back off and will reattempt transmission immediately. Excessive collisions, however, will cause loss of HTC cycle membership and a reset to the Listen state for the network element. Thus, HTC-compliant network entities will always gain access to the medium over non-HTC-compliant network entities during the ATTC, with “rogue” (non-HTC-compliant) network entities being effectively deferred until the RTC, when 802.3 compliant network entities employ the truncated binary exponential back-off algorithm in full compliance with the 802.3 standard. With reference now to FIG. 5, a protocol hierarchy diagram for adaptive channel allocation in accordance with a preferred embodiment of the present invention is depicted. The adaptive channel allocation protocol (ACAP) is implemented to efficiently utilize the B-Channels of the MAC protocol described above by exchanging messages with peer ACAPs over the D-Channels. The B-Channel resources of the MAC protocol may be viewed as network resources which, although belonging to a specific network entity at any instance in time, should not remain idle when they could be utilized by other network entities in order to optimize the efficiency of the network as a whole. Therefore, the concept of “residual” B-Channels, defined as the amount of unused B-Channels at any point within the ATTC representing excess bandwidth available to network entities transmitting within the ATTC, is introduced. Excess B-Channel bandwidth may be left unused, simply making the RTC start earlier. However, the ACAP provides a framework for manipulating the allocation of B-Channels, and is concerned with implementation of decisions about which B-Channels to allocate and which to de-allocate. To decide the B-Channel TCR and to determine the the ATTC:RTC ratio, the ACAP may employ a Bayesian decision network utilizing microeconomic quantities to model network conditions and aid in optimization of decision making. While concepts from microeconomics are borrowed for the exemplary embodiment, the ACAP provides a framework allowing any decision network based on other principles to be employed. The protocol hierarchy is depicted in FIG. 5 as a communication stack 502, with layers at or above the user application layer being omitted for clarity. The ACAP layer 504 is depicted as a layer two logical link control (LLC) protocol since it manages the allocation of virtual channel access among network entities. The ACAP layer 504 overlies the MAC layer 506 previously described and includes, in the exemplary embodiment, a Bayesian decision network 504a. User applications 508a-508n are also depicted and may represent entities at or above layer three. An application program interface (API) 510 is defined for the ACAP layer 504 to standardize calls between the user applications 508a-508n and the ACAP layer 504. In addition to providing a conventional “send” and “receive” interface to user applications 508a-508n, the ACAP interface 510 preferably provides a “submit” facility which may be utilized to inform the ACAP layer 504 of impending transmission requirements should such information be available to the user application. Provision of such transmission requirements beforehand is in the interest of the user application, to assist the ACAP layer 504 in negotiating for and acquiring B-Channel bandwidth in anticipation of the transmission load. The exemplary embodiment employs an approach to channel allocation based on the notion of pareto optimality, as generally defined in microeconomics literature, with network bandwidth supply and demand modelled to yield a B-Channel allocation process which seeks to achieve pareto optimality. A performance level is considered pareto optimal herein if, and only if, there is no other achievable performance level in which the performance of one set of agents can be increased without a concomitant performance degradation for another set of agents. In application to the transmission decision network of the present invention, the key concept of pareto optimality is that network entities will only allocate B-Channels if the allocation yields a win-win situation for both the network entity and the network as a whole. A network entity will not submit to an allocation unless the resulting transmission yields a higher utility for the network entity and consequently for the network as a whole, since the subject network entity will only be able to utilize residual B-Channels in the ATTC to the extent that other network entities have not utilized their B-Channel concentration ratio. Performance must be defined and measured on a network element basis to achieve network wide performance optimality. Performance is defined as a combination of throughput and medium utilization. Throughput is the success rate of a transmitter entity determined by the ratio of the number of successfully transmitted packets divided by the cumulative number of attempts made to transmit those packets. Utilization is the proportion of the available bandwidth which is utilized by the network entities (that is, which is not wasted to collisions). Latency, the amount of time which a transmitter entity must wait before gaining access to the medium, may also be considered as a performance measure. Optimal network performance is viewed as the performance level in which all individual network entities achieve their highest possible performance level given that they coexist in a network with other network entities, an important concept since optimal network performance does not necessarily provide the highest throughput from the medium perspective. If only 20% of all network entities are utilizing all of the medium's bandwidth capacity, medium performance may be high but network performance is obviously not optimal. The use of Bayesian decision network 504a provides a mechanism to instill prior knowledge in the network and permits random variable (decision network node) values to be updated at run time according to fictitious transmission economy conditions. To the extent that the decision network 504a accurately depicts true economic marketplace dynamics, pareto optimality is achievable. The transmission “marketplace” is modelled using B-Channel bandwidth and network entity bandwidth requirements to compute excess demand and B-Channel price. The ACAP layer 504 utilizes the Bayesian decision network 504a when making allocation decisions regarding B-Channel bandwidth, incorporating probabilistic estimates of current marketplace conditions and transmission requirements of the subject netowrk entity and other network entities. The “goods” in the transmission marketplace are B-Channels, with the medium transmission speed (e.g., 10BaseT, 100BaseT, or Fiber) decoupled from the total bandwidth available using the HTC. The total bandwidth available in one ATTC is TotalBandwidth=BT=N*MTCR where N is the total number of network entities currently participating in the ATTC and MTCR is the maximum transmission concentration ratio. Hence, the total bandwidth of the network is the total number of B-Channels available in a transmission lifetime, allowing network entities to measure the capacity of the shared medium by the number of B-Channels which may exist within an HTC. The value assigned to MTCR is subject to the physical characteristics of the transmission medium and may be higher on high speed transmission media than for lower speed transmission media. The initial bandwidth within the ATTC belonging to a specific network entity is: {overscore (X)}i=MTCR=50 where the bar indicates an initial value while the subscript i indicates network entity i, such that Xi indicates the physical B-Channels available to the network entity i should it require transmission. Virtual B-Channels, Vi, may be thought of as accumulated wealth of a network entity as a result of not transmitting on its ATTC sub-cycle, which in effect simulates a trade of B-Channels by the network entity to the network, where the network entity is paid by building up virtual B-Channels wealth. The virtual B-Channels which a network entity owns may be converted to physical B-Channels when the network entity executes an allocation decision, so: V i P b = Number of B - Channels which may be allocated where Pb is the current market price (in B-Channel multiples) of a B-Channel. It is noteworthy that the transmission probability is always 1.0. Since a TDM scheme is implemented over an asynchronous channel, when attempting transmission on the channel that channel is expected to be available to the network element. Furthermore, the adaptive MAC protocol of the present invention is aggressive and will not back-off exponentially as would a standard 802.3 compliant network entity. Price in the transmission marketplace of the exemplary embodiment is defined in terms of B-Channel multiples, with a single B-Channel having a price multiple of 1.0 at startup time. {overscore (P)}i=1.0 is the initial price multiple of a B-Channel At run time this multiple fluctuates up or down as determined by the excess demand in the network transmission economy. A network entity computes its perception of the value of a B-Channel in terms of B-Channel multiples or B-Channel price. A network entity which is assigned membership in the HTC is allocated MTCR (default 50) B-Channels. This allocation of bandwidth has no explicit impact on existing members of the HTC, but results in an inherent redistribution of wealth. Before the newly arrived network entity joined the HTC, the total relative ownership of any particular network entity is: ( 1 N ) * B T . After the new network entity joins the HTC, the relative ownership of all participating network entities becomes: ( 1 N + 1 ) * B T . The initial B-Channel frame generation rate of a network entity is: {overscore (Λ)}i=0.0. The number of B-Channels Ui which are currently in use by network entity i is: {overscore (U)}i=0. It should be noted that: ∑ i = 1 N U i ≤ ∑ j = 1 N X j . Network-wide total demand DNET for B-Channels may be computed by: D NET = ∑ i = 1 N Λ i where Λi is the frame generation rate of network entity i. Network-wide excess demand is computed from: Δ D NET = D NET - ∑ j = 1 N X j = ∑ i = 1 N Λ i - ∑ j = 1 N X j while network entity excess demand is computed from: ΔDNEi=Λi−Xi. Network-wide total B-Channel supply of unused B-Channels is computed as: S NET = B T - ∑ i = 1 N U i . The money supply in the transmission marketplace of the exemplary embodiment maps directly to virtual B-Channels. A network entity which de-allocates (does not utilize) physical B-Channels is paid in virtual B-Channels, such that Vi for a network entity i is the amount of money which that network entity owns. When a network entity allocates B-Channels that are not assigned to it, it pays virtual B-Channels to the network, although the allocating network entity will recover costs by providing transport service to some applications residing within the network entity by requiring compensation (income) in return for transport services rendered. Applications need not be aware of this scheme, since the ACAP layer may be required to compensate itself periodically based on transport services provided to user applications. The amount of transport service income Ii for a network entity is computed as: I i = ( R i + ( R a 10 ) ) * ∑ B a where Ri is the priority of the network entity, Ra is the priority of the user application, and Ba is the B-Channel utilized for the application. This implies that network entities must be assigned priorities and that applications within a network entity must also be assigned priorities. For example, a network entity may have a network-wide priority of 5, and an application within that network entity may have a priority of 2, for a combined priority of that specific application within that-particular network entity of 5.2. This translates to more income for the ACAP than if the ACAP were servicing an application with a combined priority of, say, 5.1. A B-Channel's current market price is computed based on current network-wide excess demand and current network-wide supply, as well as a domain specific constant c: {circumflex over (P)}b=Pb*1.0+c*(ΔDNET−SNET) From this price computation, it may be seen that if the message-driven frame generation rate Λi, which is represented in ΔDNET, goes up, then the price of a B-Channel also goes up, with the new B-Channel price being computed by the network entity from the equation above. A network entity's initial total worth in terms of B-Channel multiples may be computed from: {overscore (W)}i={overscore (X)}i, which implies that a network entity's worth at startup is simply the number of physical B-Channels which it owns. A history of network entity wealth may be retained to permit a network entity to exit the HTC and retain its wealth for use as its initial wealth upon rejoining the HTC. At run time, the network entity's total worth consists of its physical B-Channels and the number of B-Channels which it is able to allocate utilizing the current market price principle: W i = X i + [ V i + I i P b ] . During each HTC, each network entity computes the marketplace values as described above and then proceeds to update the decision network, which may be designed and built off-line with prior probabilistic information but is updated at run time. After the network entity retrieves the optimal decision from the decision network, directives are issued to the MAC layer in the form of a D-Channel transmission profile. Referring to FIG. 6, a high level flow chart summarizing a process of adaptive channel allocation in accordance with a preferred embodiment of the present invention is illustrated. The process is implemented within an HTC-compliant network entity as described above, and begins with step 602, which depicts start up of the network entity and/or the network entities communications with the network. The process first passes to step 604, which illustrates loading the decision network, and then to step 606, which depicts detecting and acquiring membership in the HTC. If the HTC is not detected, then an HTC is initiated by the network entity. Until HTC membership is acquired, the network entity continues to transmit according to the standard 802.3 CSMA/CD protocol. The process next passes to step 608, which illustrates the network entity perceiving the transmission marketplace conditions from the D-Channel transmission profiles from other network entities, and then to step 610, which depicts the network entity computing marketplace values for B-Channels as described above. The process passes next to step 612, which illustrates the network entity updating the decision network based with the perceived probabilistic estimates for marketplace values, and then to step 614, which depicts the network entity optimizing the decision network and retrieving the decision—that is, the best TCR—from the decision network. The process then passes to step 616, which illustrates incorporating the result of the decision into the transmission profile for the network entity, which will then be transmitting during the network entity's assigned sub-cycle within the ATTC. The process then returns, for the next HTC, to step 608, and repeats the processes of steps 608 through 616 for each HTC until the network entity leaves the network. With reference now to FIG. 7, a decision network for adaptive channel allocation in accordance with an exemplary embodiment of the present invention is depicted. The decision network may be generated off-line utilizing off-the-shelf tools, and represents the transmission marketplace as it relates to B-Channel allocation. The objective of the decision network is to decide on behalf of the ACAP agent what would be the optimal setting for the TCR and the ATTC:RTC ratio. Every network entity performs the necessary channel allocation computation, which must be implemented, updated, and optimized honestly within each network entity although the decision network gives network entities a significant degree of autonomy in reaching a decision. The decision network of the exemplary embodiment models the transmission medium activities as marketplace quantities and is updated at run time with total supply, excess demand, and other measured (perceived) values by the ACAP agent, which then proceeds to optimize the decision network to obtain the optimal TCR and ATTC:RTC ratio for the network entity under current loading conditions. While the MAC protocol permits exchange of explicit information among network elements, this facility is not utilized in order to maintain autonomy in the network entities. Decision networks (also referred to as “influence diagrams”) are belief networks with additional node types for actions and utilities. Belief networks employ nodes to represent random variables in a domain, a quantity which represents some characteristic or entity within the domain which may have a random value yet to be determined. A node in a belief network represents a random variable, and specifically the random variable's values and the probability of the correctness of that value. Nodes are linked in influence diagrams to represent dependencies between the random variables, with the absence of a link (arc) between nodes representing conditional independence of the nodes from each other. Using Bayes' rule, this can simplify the computation for the results of a query. An arc from one node to another in a belief network signifies that the first node has a direct influence on the second, with each node including a conditional probability table quantifying the effects of the parent node(s) on the child. Belief networks are directed acyclic graphs (DAGs). Thus, a decision network in accordance with the exemplary embodiment represents state information about the domain at some instant in time and the possible actions (decisions), for determining the resulting utility of the target state if the action is taken. The decision network 702 of the present invention includes Ethernet Station Count node 704, which represents the “rogue” network entities (standard 802.3 compliant) which may be residing and transmitting on the network. Standard 802.3 compliant network entities are not compliant with the ATTC, which implies that HTC-compliant network entities are unable to explicitly monitor D-Channel type information generated by the rogue Ethernet stations. HTC-compliant network entities may perceive the existence of rogue Ethernet stations by observing the number of collisions occurring during the ATTC or by tracking source MAC addresses. The number of 802.3 compliant Ethernet stations affects the collision rate in the ATTC, represented by Atc Collision Rate node 706, and the success rate in the RTC, represented by Rtc Success Rate node 708. The effect is typically expected to be negative, meaning that more rogue Ethernet stations results in a greater number of collisions which HTC-compliant network entities may anticipate in both phases of the HTC. HTC Station Count node 710 represents the current count of HTC compliant network entities, which will typically but not necessarily be known for certain (new arrivals or an error in D-Channel transmissions could affect the accuracy of this value). The HTC station count directly affects how successful transmission will be in the RTC, represented by Rtc Success Rate node 708, since the HTC compliant network entities revert to standard 802.3 transmission during the RTC. Additionally, the number of HTC stations affects the length of the RTC, represented by Rtc Bandwidth node 712, since the duration of the RTC is a proportion of the current TCR. Modify TCR node 714 is a decision node. The main objective of decision network 702 is to determine whether to modify the current TCR and, if so, by how much. Obviously, modification of the value in node 714 directly affects the value of TCR node 716, which represents the current TCR, and also affects the RTC bandwidth, represented by Rtc Bandwidth node 712, since the RTC duration is a proportion of the ATTC which is based, in turn, on the current TCR. TCR node 716 also affects the success rate in the ATTC, represented by Atc Success Rate node 718, since a higher TCR results in more time and sub-cycles in the ATTC and more opportunities to transmit B-Channels as opposed to 802.3 frames during the RTC. Rtc Bandwidth node 712, which represents the duration of the RTC, affects the success rate within the RTC, represented by the Rtc Success Rate node 708, since a longer duration RTC, or more bandwidth allocated to the RTC, provides more opportunity to successfully transmit within the RTC. Rtc Success Rate node 708 represents how successful the network entities will be during the RTC, where success rate is measured by throughput, defined as the number of successful transmissions divided by the number of attempted transmissions. The RTC success rate directly affects the utilization rate within the RTC, represented by Rtc Utilization node 720, and also affects the excess demand in the network, represented by Excess Demand node 722, since a low success rate will cause traffic build up in the network entity and thus create a differential between queued traffic and available bandwidth for growth. Atc Success Rate node 718 represent success (throughput) during the ATTC phase. Although all D-Channel and B-Channel transmissions will eventually prevail due to the aggressive contention resolution policy, they may be hindered by the existence of rogue 802.3 Ethernet stations. Thus, the success rate in the ATTC is affected by the collision rate due to 802.3 entities. The success rate also affects utilization of the medium during the ATTC phase, represented by Atc Utilization node 724, and the excess demand, represented by Excess Demand node 722, since a low success rate translates to queued traffic causing the differential discussed earlier. The Application Generation Rate node 726 represents the message generation rate of local applications on the network entity, an estimate at best when the application itself submits the future anticipated message generation rate. The message generation rate affects: ATC utilization, node 724; RTC utilization, node 720; excess demand, node 722; and also, indirectly, virtual channel wealth, represented by Virtual Channels node 728. ATC utilization is affected since excessively low generation rates will not provide sufficient messages queued or available for transmission during the ATTC, a symptom observed during simulation testing described below. RTC utilization is affected for the same reason. Excess demand is affected since very high generation rates may, depending on the success rates in the ATTC and RTC, cause a backlog of messages for transmission, rendering existing bandwidth insufficient. Virtual channel wealth is affected since the message generation rate will consume the existing, available virtual channel wealth, although the relationship is not explicitly shown since it is implicit from utilization nodes. ATC utilization is the bandwidth employed by successful transmissions during the ATTC, a ratio measure of successful bandwidth usage to total available bandwidth. ATC utilization, represented by node 724, affects virtual channel wealth, node 728, since higher utilization levels make it more likely that the network entity is accumulating income in the form of virtual channels from resident applications. RTC utilization is the bandwidth utilized for successful transmission during an RTC phase. This affects virtual channels wealth, node 728, since more utilization increases the likelihood that the network entity is receiving virtual channels from local applications as compensation for transport services. Virtual channels wealth, node 728, represents the amount of virtual B-Channels owned by the network entity at any given time. Together with the value of B-Channel Price node 732, which represents the cost, in B-Channel multiples, of physical B-Channels at any given time, the value of node 728 determines the costs to the network entity of providing transport services to the resident application, thus affecting Net Income node 730. The value of Excess Demand node 722, which represents the network entity's excess demand value in terms of B-Channel requirement, is affected by the network entity's message generation rate and by success rates in both the ATTC and RTC. Excess demand causes the network entity to formulate a perception of current market price. Net Income node 730 represents the compensation which the network entity may expect from local applications for transport services, income in the form of virtual B-Channels. This value provides a measure of how profitable the network entity is in providing services to resident applications on a virtual channels measure at the current B-Channel price. The value of node 730 is affected by Priority node 734, which represents the network entities priority within the network, and Application Priority node 736, which represents the priority of the application requesting transport services within the network entity. Node 730 serves as a utility node. The utility measure of Net Income node 730 may be calculated, for example, from NetIncome(VirtualChannels, ApplicationPriority, Priority)=(100*Priority)+(10*ApplicationPriority)−(55*VirtualChannels). This utility measure is a reflection of the value of Net Income node 730. The network entity achieves maximum utility when income is high, and income is a reflection of the level of payment, or priority, of resident applications and the virtual channel repository, which reflects cost, of the network entity. Experimentation with the decision network indicates that updating nodes in the network causes the TCR ratio to be changed favorably to the utility of the network entity. Referring to FIGS. 8A through 8K, plots from simulations of a shared transmission medium utilizing standard 802.3 compliant and/or HTC-compliant network communications under various conditions and combinations of network entities are illustrated. These simulations were run utilizing the source code listed in Appendix I and II under the well-known Netica (Netica is a trademark of Norsys Corporation) application, a product of Norsys Corporation, and Maisie, an off-the-shelf C-based discrete-event simulation tool developed by the UCLA Parallel Computing Lab. FIG. 8A is a standard 802.3 compliant only simulation providing a base performance against which to compare other simulation results. The highest throughput determined in this simulation is about 0.70, with the intersection of utilization and throughput at approximately (38, 0.45) being a reasonable operating condition. In fact, 30 is the maximum number of active stations permitted under 10Base2. FIG. 8B is an HTC-compliant only simulation showing that throughput remains relatively high at increased network entity populations. Better throughput and utilization is reflected, with the utilization measure far exceeding the 802.3 only simulation. Throughput is actually degraded because of the RTC phase during which network entities revert to pure 802.3 transmission. Latency increases linearly with network entity population. FIGS. 8C, 8D, and 8E are a mixed simulation with low HTC population and high 802.3 population. FIG. 8C simulates performance of the 802.3 components, demonstrating that 802.3 entities may perform almost as well in an HTC transmission environment as in a pure 802.3 environment. This suggests that implementing TDM sub-cycles utilizes medium bandwidth which otherwise would have found only minimal additional usage. For example, the point (21-49, 0.36) exhibits substantially the same metrics as 50 network entities in the 802.3 only simulation of FIG. 8A. FIG. 8D simulates performance of the HTC-compliant components, and shows that HTC-compliant network entities perform very well relative to an HTC-compliant only environment. Utilization in the mixed mode declines as a result of lost utilization consumed by 802.3 entities, but total utilization for both 802.3 and HTC-compliant entities, taken from FIGS. 8C and 8D, respectively, is approximately 1.0. FIG. 8E shows combined performance, and exhibits throughput comparable to pure 802.3 transmission and utilization similar to that of HTC-compliant only transmission, a favorable result indicating that TDM transmission during the ATTC extracts slack in bandwidth from 802.3 only transmission environments. FIGS. 8F, 8G and 8H are a mixed simulation with high HTC-compliant population and low 802.3 population. Performance of 802.3 entities, shown in FIG. 8F, remains comparable to but slightly lower than the 802.3 only environment and is almost identical to the mixed environment with low HTC-compliant and high 802.3 entities shown in FIG. 8C. Comparisons made on a point by point basis—for example, the point (42-18) in FIG. 8F and point (9-21) in FIG. 8C, which is roughly the same number of 802.3 compliant entities—are probative. The performance of HTC-complaint entities, shown in FIG. 8G, improves with a higher population of HTC-compliant entities, as seen by comparing FIG. 8G with FIG. 8D. Again, point by point comparison of roughly corresponding entity numbers—e.g., point (28-12) in FIG. 8G with point (30-70) in FIG. 8D—is necessary. The combined performance of the high:low mix, illustrated in FIG. 8H, shows better overall performance than the low:high mix shown in FIG. 8E, indicating that implementation of the TDM transmission in the HTC improves overall performance. FIGS. 8I, 8J, and 8K are a mixed simulation with equal HTC-compliant and 802.3 populations. Performance of 802.3 entities, shown in FIG. 8I, is similar to high:low and low:high mixes of FIGS. 8C and 8F, respectively, with metrics being almost equal on a point by point basis. Performance of HTC-compliant entities, illustrated in FIG. 8J, is better than that in the low:high mix of FIG. 8D but worse than that in the high:low mix of FIG. 8G, an expected result since HTC transmissions will increasingly dominate under larger percentages of entities which are HTC-compliant. Combined performance, shown in FIG. 8K, indicates that network performance is not as good as under the high:low mix of FIG. 8H but better that the low:high mix of FIG. 8E, an expected result supporting the assertion that HTC transmission adds value to overall network performance. The present invention provides a framework for implementing time division multiplexing at the medium access control layer of a network entity, a framework which interfaces with the logical link control layer in which the controlling agent resides. The agent guides the MAC in optimally accessing the medium. In the exemplary embodiment, a decision theoretic agent employing a decision network modelling the transmission network on microeconomic principles was selected, but other agents may be substituted. By representing the transmission state of the network as a transmission marketplace and iteratively optimizing the network at run time, the exemplary embodiment implements a microeconomic based decision network on the principle of pareto optimality under which the network entity allocates B-Channels for transmission only if the resulting state after the allocation is utility maximizing to the network entity and the network. Throughput and latency degradation under increasing loading conditions resulting from increase in collisions is reduced or eliminated with the adaptive TDM of the present invention. Backwards compatibility with conventional 802.3 transmission is maintained by hybridization of the transmission cycle to include an 802.3 compliant transmission phase, which is exploited as a membership grace period for new HTC-compliant members. Priority based throughput improvement is also possible in the present invention, which provides a framework for any type of decision agent or network. It is important to note that while the present invention has been described in the context of a fully functional data processing system and/or network, those skilled in the art will appreciate that the mechanism of the present invention is capable of being distributed in the form of a computer usable medium of instructions in a variety of forms, and that the present invention applies equally regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of computer usable mediums include: nonvolatile, hard-coded type mediums such as read only memories (ROMs) or erasable, electrically programmable read only memories (EEPROMs), recordable type mediums such as floppy disks, hard disk drives and CD-ROMs, and transmission type mediums such as digital and analog communication links. While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to communication between multiple devices over a single, shared transmission medium, and more specifically to employing an adaptive medium access control protocol together with a corresponding logical link control protocol supporting adaptive channel allocation to improve device communication over a shared transmission medium. 2. Description of the Prior Art Several access control methodologies exist for transmission on multi-access channels within a single transmission medium. Token ring and token bus schemes control access to the transmission medium in an orderly fashion designed to maximize bandwidth utilization and to maintain fairness (priorities) and determinism. Token ring and token bus schemes may be viewed as forms of multiplexing (MUXing), which may be loosely defined as combining two or more information channels onto a common transmission medium. Based on the premise that a transmission medium's speed and capacity far exceed a single user's requirements on any end of the communication medium, and the logical conclusion that several transmitting entities may be able to utilize the same transmission medium, multiplexing typically divides the medium transmission time into “timeslots”. Each timeslot is then uniquely assigned to a single transmitting entity, which owns the medium for the full duration of the timeslot and may transmit on the medium only during that assigned portion of time, and is the only transmitting entity permitted to transmit during that assigned portion of time. Time division multiplexing (TDM) thus achieves shared access to a single transmission medium by defined division of transmission time among the transmitting entities. In environments where usage requirements of transmitting entities may vary significantly at run time, statistical time division multiplexing (STDM), in which timeslot duration is not predetermined or fixed but instead varies at run time, may alternatively be employed. Ethernet-type medium access control schemes, on the other hand, generally allow a network element to transmit at will on the transmission medium. While non-deterministic in nature, this system possesses several attractive characteristics, including simplicity, support for dynamic changes in network element population, autonomous network element operation, low transmission latency at low utilization levels, and acceptable throughput under average loading conditions. Drawbacks of Ethernet include degradation of throughput under heavy traffic loading, non-determinism, and absence of priority assurance. Ethernet throughput rates are typically in the range of 20% to 50% depending on the specific implementation, and drop drastically from those levels when the transmission medium is heavily loaded. Current Ethernet transmission medium access control utilizes the truncated binary exponential back-off algorithm, a simple algorithm by which a transmission controller chip may adapt access to the medium according to the medium loading condition. The basic outcome of the algorithm is minimal latency and acceptable throughput and utilization under light loading conditions, with increased latency and acceptable throughput and bandwidth utilization as traffic increases towards heavy traffic conditions. It would be desirable, therefore, to provide a shared medium control access methodology which exploits the benefits of Ethernet-type systems while providing some levels of determinism, priority, and sustained throughput efficiency with increasing traffic loads. It would also be advantageous for the methodology to conduct adaptive channel allocation of transmission jobs into virtual channels on the medium.
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<SOH> SUMMARY OF THE INVENTION <EOH>A hybrid transmission cycle (HTC) unit of bandwidth on a shared transmission medium is defined to include an adaptive, time division multiplexing transmission cycle (ATTC), which is allocated in portions sequentially among all participating network entities, and a residual transmission cycle (RTC), which is allocated in portions, as available, to the first network entity requesting access to the shared medium during each particular portion. The ratio of logical link virtual channels, or D-Channels, to data payload virtual channels, or B-Channels, within the ATTC is adaptive depending on loading conditions. Based on transmission profiles transmitted on the D-Channels during the ATTC, each network entity determines how many B-Channels it will utilize within the current HTC. This calculation may be based on any decision network, such as a decision network modelling the transmission medium as a marketplace and employing microeconomic principles to determine utilization. The ratio of the duration of the ATTC segment to the duration of the RTC segment is also adaptive depending on loading conditions, to prevent unacceptable latency for legacy network entities employing the shared transmission medium. During the RTC, utilization of the shared medium preferably reverts to IEEE 802.3 compliant CSMA/CD transmission, including transmissions by HTC-compliant network entities.
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20040702
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20100518
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20050526
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67978.0
| 29
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HSU, ALPUS
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ADAPTIVE TRANSMISSION IN MULTI-ACCESS ASYNCHRONOUS CHANNELS
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SMALL
| 1
|
CONT-ACCEPTED
| 2,004
|
|||
10,884,643
|
ACCEPTED
|
Stripe removal system
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A system for removing paint and other coatings from hard surfaces is mounted on a truck for over-the-road travel. The truck bed carries a high power vacuum pump, a self propelled tractor with an attached blast head, a liquid reservoir, a sump or vacuum tank, and a ramp for loading the tractor. The reservoir is connected to a low pressure pump that transfers water to the high pressure pump. The high pressure pump is connected to the blast head by a high pressure hose. A vacuum hose is connected to the sump which has an internal enclosure for separating the waste materials from the liquid for easy dumping of semi dried materials.
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1. A cleaning system for removing coatings from a hard surface by high pressure liquid comprising a liquid reservoir connected to a high pressure pump, said pump connected to a mobile blast head by a high pressure hose, said blast head having at least one high pressure nozzle for delivering high pressure liquid onto a hard surface, a waste removal hose connected at one end to said blast head and at the other end to a sump for collection of liquid and coating, said sump connected to said liquid reservoir, whereby liquid is pumped through said high pressure hose from said reservoir and exits said high pressure nozzle onto the hard surface removing coatings therefrom, said liquid and coatings entrained by said waste removal hose to said sump, said coatings collected in said sump and the waste liquid exiting through said outlet. 2. A cleaning system of claim 1 wherein a high power vacuum pump is connected to said sump. 3. A cleaning system of claim 2 wherein a shroud is connected to said blast head, said shroud surrounds said at least one nozzle and forms a negative pressure chamber. 4. A cleaning system of claim 3 wherein said liquid reservoir, said sump and said high power vacuum pump are mounted on a mobile frame, said mobile frame forms an integral part of a truck having a bed and an cab, said truck being self-propelled. 5. A cleaning system of claim 3 wherein said mobile blast head is attached to a wheeled chassis for maneuvering over the hard surface. 6. A cleaning system of claim 5 wherein said wheeled chassis is attached to a self-propelled tractor and said mobile blast head and tractor are of a size for removably docking transversely on said bed of said truck. 7. A cleaning system of claim 6 wherein said bed includes a ramp, said ramp connected to said bed for raising and lowering said ramp, said ramp sized to support said tractor for docking transversely on said bed. 8. A cleaning system for removing coatings from a hard surface by high pressure liquid comprising a water reservoir connected to a high pressure pump, said pump connected to a mobile blast head by a high pressure hose, said blast head having at least one high pressure nozzle for delivering high pressure liquid onto a hard surface, a liquid and debris removal hose connected at one end to an inlet of a vacuum chamber and connected at the other end to said blast head to remove liquid and coating from said blast head, a high power vacuum pump connected to said vacuum chamber, said vacuum chamber having a rigid outside wall defining an interior, a wire mesh screen in said interior spaced inwardly of said rigid outside wall and forming an enclosure, said inlet inside said enclosure, said vacuum chamber having an outlet for the liquid, said outlet between said rigid wall and said enclosure, said outlet of said vacuum chamber connected to said reservoir for re-circulation of the liquid, whereby liquid is pumped through said high pressure hose from said reservoir and exits said high pressure nozzle onto the hard surface removing coatings therefrom, said liquid and coatings entrained by said high powered vacuum in said vacuum hose to said vacuum chamber through said inlet, said coatings collected by said filter screen in said vacuum chamber and the liquid exiting through said outlet. 9. A cleaning system of claim 8 wherein a porous flexible bag is removably inserted in said enclosure, said bag having a mouth surrounding said inlet whereby said coatings are collected in said bag. 10. A cleaning system of claim 8 wherein said reservoir, said vacuum chamber, said vacuum pump and said blast head are mounted on the bed of a truck. 11. In a cleaning system for removing coatings from a hard surface by high pressure liquid comprising a mobile blast head including at least one high pressure nozzle for directing high pressure liquid onto a hard surface, an articulating link attaching said blast head to a self propelled tractor, said link having a leading end and a trailing end, said blast head connected to said leading end, said trailing end connected to said tractor whereby said blast head is movable horizontally and vertically in relation to a hard surface. 12. In a cleaning system of claim 11 wherein said tractor has a pair of front wheels spaced apart, a bar fixed to said tractor between said front wheels, said link having trailing arms rotatably connected to said bar for rotation in a horizontal plane, said link either fully to the left or right an then fully vertically. 13. A process for removing material comprising the steps of: 1. providing a vacuum tank and a water tank with a connection valve therebetween, closing of said connection valve; 2. inserting a filter material in said vacuum tank; 3. creating a vacuum in said vacuum tank by use of a vacuum pump powered by an internal combustion engine; 4. directing ultra high pressure water at a material to be removed creating a debris slurry, said slurry drawn into said vacuum tank being trapped in said filter. 5. breaking of the vacuum when said vacuum tank reaches full capacity; 6. draining water from said vacuum tank through said filter material; and 7. repeating steps 1-7 until said filter bag is filled. 14. A process for removing material comprising the steps of: 1. providing a vacuum tank and a water tank with a connection valve there between, opening said connection valve; 2. inserting a filter material in said vacuum tank; 3. creating a vacuum in said vacuum tank by use of a vacuum pump powered by an internal combustion engine; 4. directing ultra high pressure water at a material to be removed creating a debris slurry, said slurry drawn into said vacuum tank being trapped in said filter. 5. allow water to pass from said vacuum tank through said connection valve to said water tank when the water level rises to the level of said connection valve; 6. closing of said connection valve releasing vacuum from said water side tank; 7 draining of water from said water tank; 8. closing said drain valve; 9. opening said connection valve; 10. repeating steps 1-9 until said filter bag is filled.
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FIELD OF THE INVENTION This invention relates to the field of high pressure water cleaning devices for highways, runways, parking decks, and other hard surfaces. PRIOR ART BACKGROUND The use of paint stripes on road surfaces is the accepted method to indicate vehicle lanes, crossing lanes, parking areas and numerous other indicators. Various pavement marking techniques are known, including the use of traffic paint, thermoplastic, epoxy paint and preformed tapes. Common pavement surfaces are asphalt and concrete. Most pavement marking systems are intended to be as durable and permanent as possible, and resistant to weathering and wear from traffic. The removal of such striping is typically required when the road is to be resurfaced or if the indication is to be changed. The removal of such stripes is typically performed by use of abrasive wheels, grinding teeth, or the blasting of abrasive particles against the material to be removed. The use of these carbide teeth and grinding wheels results in an undesirable trench or groove in the road. For example, paint, when used for roadway marking, penetrates into the pavement, perhaps ⅛-⅜ inch, so that mere surface removal of the paint is not sufficient to remove the marking. For example, a pavement marking removal technique that uses abrasive wheels or teeth can create excessive heat which may be suitable for removing painted markings but can melt thermoplastic materials causing equipment to gum up, by reconstituting the thermoplastic. Current pavement marking removal machines typically employ various forms of cutting devices to remove the marking material, as well as a portion of the underlying layer of pavement material, for example, ⅛-⅜ inch, in order to effectively remove painted lines, including paint which has penetrated the porous pavement. A common type of machine employed for removing pavement marking is known as a “Road Pro” grinder manufactured by Dickson Industries, Inc., in Dickson U.S. Pat. No. 5,236,278. This type of machine employs parallel passive shafts that extend between circular rotating end plates. Hardened steel star wheels are carried on the parallel passive shafts, and these star wheels strike and abrade the pavement surface. Another approach to pavement marking removal is the use of diamond saw blades arranged to make a dado cut. Still other types of machines use grinders or shot blast as described in Patent Registrations U.S. Pat. Nos. 4,753,052; 4,376,358; 3,900,969; 4,336,671; 3,977,128 and 4,377,924. NLB Corporation markets a high pressure water jet system for removing paint from pavement under the name “StarJet”. The water jet system includes a blast head frame mounted on an attachment to the front bumper of a prime-mover truck. Casters support the frame for movement over the pavement and the path of the blast head is controlled by the driver steering the truck. Because of the position of the driver and the cab body of the prime-mover, it is difficult to see the blast head's position with regard to the stripes on the pavement. Any vision at all requires the driver to lean out of the driver's side window resulting in fatigue and other non ergonomically efficient factors. Positioning the head to the passenger side is performed manually with some difficulty and greatly complicating the driver's ability to view the blast path. The driver must now position himself in an almost upright standing position. Further, due to the length of the extension holding the blast head, the angular off-set, and the swivel of the casters, the movement of the wheel of the truck is not directly related to the path of the blast head. NLB Corporation also has another system marketed under the mark “StripeJet”, that is a self propelled tractor with a blast head on the front of the tractor. The blast head has a shroud and high pressure inlet with a vacuum recovery. Another stripe removal system is marketed by the Blasters Corporation which is mounted on a truck similar to the “StarJet” device. Another model appears to be a self-powered four wheeled tractor, similar to a grass mower, which supports a driver and is connected to the prime-mover by high pressure lines for delivery of high pressure water to a blast head. The blast head is on the front of the tractor. The problem with the prior art is the inability to place an operator close to the material removal site by use of a device that has over-all dimensions that allow for easy transfer sideways on a truck or trailer having a width less than 8′6″. SUMMARY OF THE PRESENT INVENTION Briefly, disclosed is a cleaning system for removing coatings from a hard surface by high pressure liquid. The system employs a liquid reservoir connected to a high pressure pump for directing ultra high pressure water through a blast head mounted on a self-propelled mobile frame. The mobile frame is a self-propelled tractor wherein the blast head and tractor are of a size for removably docking transversely on a bed of said truck. The cleaning system is mounted on the truck or pulled behind the truck on a trailer. The truck is then tethered to the tractor during operation. The truck bed includes a ramp sized to support the tractor for docking and transport. It is an object of this invention to provide a vacuum recovery truck mounted stripe removal system having a compact unit for safe, fast over-the-road travel to job sites. It is another object of this invention to provide a unit that is quickly deployed, with hoses not having to be disconnected, and in operation at the job site. It is a further object of this invention to provide a tractor mounted blast head that is hydraulically articulated from left to right and at the same time when moved all the way to the right this also brings the blast head closer to the wheels of the tractor thereby reducing its overall dimension to under 8′6″ when in its upright and locked position to reduce the over-all dimensions of the blast head for over-the-road transportation. It is still another object of this invention to provide a blast head that is articulated to swing horizontally independently of the tractor path for more flexibility in coverage. It is a further object of this invention to provide a high pressure water jet for removal of paint or other coverings and a vacuum recovery system for the water and debris being generated. It is yet another object of this invention to provide a collection/filter receptacle for the removed materials for ease of disposal and the release of filtered wastewater. This allows an operator to easily regain all of the available capacity not occupied by paint chips or road debris of the vacuum chamber by simply releasing the dump valve. All of the remaining debris is retained until such time as the vacuum chamber is completely full of actual debris. The amount of capacity able to be regained will be continually diminished as the vacuum tank fills with debris and will eventually reach a point of inefficiency at which point it must be dumped. When the material is dumped, it is dumping semi dried, dewatered debris in which the wastewater is not mixed with the debris. Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. BRIEF DESCRIPTION OF THE DRAWINGS While the novel features of the invention are set forth with particularity in the appended claims, the invention, both as to organization and content, will be better understood and appreciated from the following detailed description, taken in conjunction with the drawings, in which: FIG. 1 is a side view of the stripe removal system; FIG. 2 is a perspective of the stripe removal system with blast head deployed; FIG. 3 is a front view of the blast head and tractor; FIG. 4 is perspective of the blast head link; FIG. 5 is a side view of the tractor with blast head stowed; FIG. 6 is a side view of the liquid reservoir and sump; and FIG. 7 is a perspective of the sump and waste removal system. DETAILED DESCRIPTION OF THE INVENTION The paint removal system 10, shown in FIG. 1, includes a prime-mover truck 11 and a trailer 12. The truck has a forward cab-over 18 for the driving controls and operator. Mounted on the bed 12 of the truck is the water reservoir 13 and the sump 14 or vacuum chamber. The reservoir and sump are interconnected by a strategically positioned duct for continuous dumping of filtered wastewater when operating from a fixed position where liquid is supplied to the high pressure pump by a means other than the reservoir 13. The sump 14 is positioned on the rear end of the bed 12. The rear portion 19 of the bed is pivotally mounted on the truck frame and hydraulicly powered to move in the vertical plane permitting dumping of the contents of the sump 14. The sump 14 is connected to the vacuum pump 15 by hose 16. The intake of a high power vacuum pump capable of approximately 1100 CFM (cubic feet per minute) is connected to the vacuum tank. The vacuum tank and pump are also mounted on the bed of the prime-mover 11. A ramp 19 is hinged to the edge of the bed 12 between the vacuum pump 15 and the cab 18. The ramp can be lowered to provide a pathway for the self propelled tractor 20. As shown, the ramp 19 is in the stowed or traveling position for highway transport. When the ramp is unfolded it is approximately 9 feet in length. The trailer 12 is removably attached to the prime-mover through a conventional trailer hitch 21. Mounted on the bed 22 of the trailer is a high pressure fluid pump greater than 25,000-40,000 psi and from 2-15 gallons per minute. A high pressure hose connects the pump with the blast head during operations. In FIG. 2 the mobile tractor 20 is illustrated in the normal operations position. The tractor is similar to a riding mower with a small engine self propelling the tractor. The blast head 23 has at least one and up to sixteen high pressure nozzles delivering high pressure fluid to the surface to be cleaned. The high pressure nozzle is carried on a chassis 24 mounted on casters 25. A shroud 27 descends from the chassis and surrounds the high pressure nozzle. The blast head is connected to the high pressure hose by line 26 and the shroud 27 is connected to the sump by waste removal hose 28. The high pressure hose 26 and the vacuum hose 28 is supported by a swinging boom 29 which is mounted on the prime mower 11 shown in FIG. 1 to provide freedom of movement for the tractor and to prevent tangling or running over of the hoses by the prime mover. As shown in FIGS. 3-5, the blast head 23 is connected to the tractor 20 by an articulated link 31 which is capable of horizontal movement, as shown in FIGS. 3 and 4, and vertical movement, as shown in FIG. 5. A bar 32 is attached to the tractor frame by rods 33 and 34. The bar 32 is located between the front wheels of the tractor. The horizontal swinging movement of the link results in a widened path of the high pressure nozzle to adjust for different widths or patterns of striping of the surface being cleaned and deviations in direction of the tractor. The horizontal movement is powered by the hydraulic cylinder 35 connected to bar 32 which may be controlled by the operator moving a joy stick on the tractor. As the hydraulic piston 36, connected to the trailing arm 37, arm 37 and 38 move, with the trailing arms rotating about pins 39 and 40 attached by brackets 41 and 42 on bar 32. The forward end of the articulated link 31 has a plate 43 connected to the forward ends of trailing arms 37 and 38. The arms 37 and 38 are rotatably connected to the plate by brackets 41′ and 42′ holding pins 39′ and 40′, respectively. The forward arms 44 and 45 are rotatably connected to the plate 43 to rotate vertically. Pins 46 and 47 extend horizontally through brackets 48 and 49. Another hydraulic cylinder 50 is connected to the plate 43 and the piston 51 is connected to the forward end of the arm 44. As the piston 51 moves, the distance between the surface to be cleaned and the blast head 23 changes. The vertical movement permits elevation changes to accommodate the contours of the surface. Further, the blast head 23 may be raised to the vertical position and then manually flipped up and back reducing the overall length to permit the tractor 20 and blast head 23 to be stowed on a truck bed sideways consuming a space of less than 8′6″ for highway travel, shown in FIG. 5. The forward ends of the arms 44 and 45 are attached by pins 52 and 53 to brackets 54 and 55 to prevent binding as the arms are manipulated. The brackets are mounted on blast head attachment plate 56. A blast head attachment plate 56 is removably connected to the chassis 24 of the blast head 23 to provide support and control of the blast head from the tractor through the link 31. The liquid reservoir 13 and the sump 14 are shown in FIG. 6. As illustrated, the liquid reservoir and vacuum chamber have a common enclosure with an internal partition dividing them. The sump 14 has an inlet 57 for connection by hose 28 to the vacuum shroud 27. An outlet 58 is connected to the vacuum pup hose 16. The liquid reservoir has a hatch 60 for inspecting and cleaning the reservoir with approximately 600-1500 gallons of liquid. An outlet 61 is connected to a low pressure pump by a low pressure suction hose 62. The low pressure 12 volt pump is used to pump water out of the reservoir 13 back to the water blasting pump 12 at about 40 Psi and 20 g.p.m. A recycling valve 63 is mounted in a connector pipe 64 having one end opening into the reservoir 13 and the other end opening into the sump 14. The connector is located near the top of the sump and reservoir to allow for some settling of debris in the sump. The valve 63 opens or closes the connection. In FIG. 7, the sump 14 is shown with the rear door 65 open for unloading the porous enclosure 64. The door has a seal (not shown) to maintain the negative pressure therein during operation. The porous enclosure may be a wire screen or mesh box sized to fit within the sump 14. An additional filter bag with having between 5-200 micron porosity may be inserted into the enclosure. The dimensions of the enclosure 64 are somewhat less than the interior of the sump which provides a marginal area 65 between the enclosure and the interior walls and floor of the sump which provides an exit path for filtered water through valve 70. The inlet 57 empties into the enclosure 64 thereby preventing coatings from being entrained in the vacuum system. One side of the enclosure is hinged and latched to permit entry into the enclosure or removal of the filter bags. By opening the sump door and raising the dump bed of the truck, the waste material can be easily and quickly removed without prolonged interruption of the operations. The filter bag is the disposal container, and is dumped with the material. A permanent filter material can also be utilized which requires cleaning after each use but does not waste a filter bag each time it is dumped. In operation, the process for using the disclosed equipment in a mobile operation for stripe removal: 1. Connection valve remains closed. Water side is used only as a fresh water supply and is not placed under vacuum at any time. 2. Filter material positioned in the vacuum tank at a distance off the walls and floor of the tank. A filter “bag” may also be hung by hooks from the ceiling to produce even cleaner waste water. 3. The vacuum tank is placed under vacuum by starting the diesel powered vacuum pump which is connected by an air outlet hose to the vacuum tank. 4. As strip material is removed creating a slurry of water and debris, the mixture is drawn through the inlet hose into the vacuum tank being trapped in the filter. 5. When the vacuum tank reaches its full capacity, a shutoff ball is forced upwards toward the air outlet hose and makes contact with a ball seal causing loss of tank vacuum. 6. The drain valve is then opened on the vacuum tank. The drain permits water to drain through the filter material and into the open cavity between the walls and floor allowing an exit from the drain. 7. The shutoff valve is closed allowing for a capacity equal to the capacity previously occupied by dirty water, only the debris slurry remains inside the tank. 8. Steps 1-7 are repeated until the strip is removed. 9. Upon opening of a door to the vacuum container, allows for a removal of all debris captured in the filter. The instant invention may also be used in a non-mobile setting in continuous operation as follows. 1. The connection valve remains open except when it is necessary to dump the water side. Water side is used as an overflow vacuum tank and is under vacuum much of the time. 2. Filter material positioned in the vacuum tank at a distance off the walls and floor of the tank. A filter “bag” may also be hung by hooks from the ceiling to produce even cleaner waste water. 3. Vacuum tank is placed under vacuum by starting the diesel powered vacuum pump which is connected by the air outlet hose to the vacuum tank. Water side is under vacuum as well by way of connection valve. 4. As strip material is removed creating a slurry of water and debris, the mixture is drawn through the inlet hose into the vacuum tank being trapped in the filter. 5. As the debris and water level rise to the level of the connection valve, the water will begin flowing through the connection valve into the water side. The water in the water side tank will be filtered water as the water has had to first flow through the filter material to reach the connection valve. 6. When the waste water has reached the level of the connection valve it will be visible to the operator through a strategically positioned sight glass. At that point, without shutting down the vacuum or the operation, the operator closes the connection valve which releases the water side tank from vacuum. 7. Next, the operator must open the drain valve on the water side to release the waste water being held there. 8. After the water tank has drained completely, the water side drain valve must be closed. 9. The connection valve is reopened allowing wastewater to flow freely into the water side box. 10. Repeating of steps 1-9 while never shutting down or affecting the blasting operation whatsoever. This may be continued until the vacuum tank is full of debris. 11. It is now necessary to shut off the vacuum power unit and open the drain valve on the vacuum tank. This allows the water to drain through the filter material, into the open cavity between the walls and floor, and exit the drain. This allows the debris to dewater. 12. Opening of the vacuum door allows for a release of all material to repeat the process. A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiment but only by the scope of the appended claims.
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<SOH> PRIOR ART BACKGROUND <EOH>The use of paint stripes on road surfaces is the accepted method to indicate vehicle lanes, crossing lanes, parking areas and numerous other indicators. Various pavement marking techniques are known, including the use of traffic paint, thermoplastic, epoxy paint and preformed tapes. Common pavement surfaces are asphalt and concrete. Most pavement marking systems are intended to be as durable and permanent as possible, and resistant to weathering and wear from traffic. The removal of such striping is typically required when the road is to be resurfaced or if the indication is to be changed. The removal of such stripes is typically performed by use of abrasive wheels, grinding teeth, or the blasting of abrasive particles against the material to be removed. The use of these carbide teeth and grinding wheels results in an undesirable trench or groove in the road. For example, paint, when used for roadway marking, penetrates into the pavement, perhaps ⅛-⅜ inch, so that mere surface removal of the paint is not sufficient to remove the marking. For example, a pavement marking removal technique that uses abrasive wheels or teeth can create excessive heat which may be suitable for removing painted markings but can melt thermoplastic materials causing equipment to gum up, by reconstituting the thermoplastic. Current pavement marking removal machines typically employ various forms of cutting devices to remove the marking material, as well as a portion of the underlying layer of pavement material, for example, ⅛-⅜ inch, in order to effectively remove painted lines, including paint which has penetrated the porous pavement. A common type of machine employed for removing pavement marking is known as a “Road Pro” grinder manufactured by Dickson Industries, Inc., in Dickson U.S. Pat. No. 5,236,278. This type of machine employs parallel passive shafts that extend between circular rotating end plates. Hardened steel star wheels are carried on the parallel passive shafts, and these star wheels strike and abrade the pavement surface. Another approach to pavement marking removal is the use of diamond saw blades arranged to make a dado cut. Still other types of machines use grinders or shot blast as described in Patent Registrations U.S. Pat. Nos. 4,753,052; 4,376,358; 3,900,969; 4,336,671; 3,977,128 and 4,377,924. NLB Corporation markets a high pressure water jet system for removing paint from pavement under the name “StarJet”. The water jet system includes a blast head frame mounted on an attachment to the front bumper of a prime-mover truck. Casters support the frame for movement over the pavement and the path of the blast head is controlled by the driver steering the truck. Because of the position of the driver and the cab body of the prime-mover, it is difficult to see the blast head's position with regard to the stripes on the pavement. Any vision at all requires the driver to lean out of the driver's side window resulting in fatigue and other non ergonomically efficient factors. Positioning the head to the passenger side is performed manually with some difficulty and greatly complicating the driver's ability to view the blast path. The driver must now position himself in an almost upright standing position. Further, due to the length of the extension holding the blast head, the angular off-set, and the swivel of the casters, the movement of the wheel of the truck is not directly related to the path of the blast head. NLB Corporation also has another system marketed under the mark “StripeJet”, that is a self propelled tractor with a blast head on the front of the tractor. The blast head has a shroud and high pressure inlet with a vacuum recovery. Another stripe removal system is marketed by the Blasters Corporation which is mounted on a truck similar to the “StarJet” device. Another model appears to be a self-powered four wheeled tractor, similar to a grass mower, which supports a driver and is connected to the prime-mover by high pressure lines for delivery of high pressure water to a blast head. The blast head is on the front of the tractor. The problem with the prior art is the inability to place an operator close to the material removal site by use of a device that has over-all dimensions that allow for easy transfer sideways on a truck or trailer having a width less than 8′6″.
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<SOH> SUMMARY OF THE PRESENT INVENTION <EOH>Briefly, disclosed is a cleaning system for removing coatings from a hard surface by high pressure liquid. The system employs a liquid reservoir connected to a high pressure pump for directing ultra high pressure water through a blast head mounted on a self-propelled mobile frame. The mobile frame is a self-propelled tractor wherein the blast head and tractor are of a size for removably docking transversely on a bed of said truck. The cleaning system is mounted on the truck or pulled behind the truck on a trailer. The truck is then tethered to the tractor during operation. The truck bed includes a ramp sized to support the tractor for docking and transport. It is an object of this invention to provide a vacuum recovery truck mounted stripe removal system having a compact unit for safe, fast over-the-road travel to job sites. It is another object of this invention to provide a unit that is quickly deployed, with hoses not having to be disconnected, and in operation at the job site. It is a further object of this invention to provide a tractor mounted blast head that is hydraulically articulated from left to right and at the same time when moved all the way to the right this also brings the blast head closer to the wheels of the tractor thereby reducing its overall dimension to under 8′6″ when in its upright and locked position to reduce the over-all dimensions of the blast head for over-the-road transportation. It is still another object of this invention to provide a blast head that is articulated to swing horizontally independently of the tractor path for more flexibility in coverage. It is a further object of this invention to provide a high pressure water jet for removal of paint or other coverings and a vacuum recovery system for the water and debris being generated. It is yet another object of this invention to provide a collection/filter receptacle for the removed materials for ease of disposal and the release of filtered wastewater. This allows an operator to easily regain all of the available capacity not occupied by paint chips or road debris of the vacuum chamber by simply releasing the dump valve. All of the remaining debris is retained until such time as the vacuum chamber is completely full of actual debris. The amount of capacity able to be regained will be continually diminished as the vacuum tank fills with debris and will eventually reach a point of inefficiency at which point it must be dumped. When the material is dumped, it is dumping semi dried, dewatered debris in which the wastewater is not mixed with the debris. Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
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20040702
|
20070814
|
20060105
|
77734.0
|
B08B504
| 1
|
HUSBAND, SARAH E
|
STRIPE REMOVAL SYSTEM
|
SMALL
| 0
|
ACCEPTED
|
B08B
| 2,004
|
|
10,884,693
|
ACCEPTED
|
Data I/O system using a plurality of mirror volumes
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A data I/O system comprises a plurality of storage devices and a controller which controls the storage devices. In the data I/O system, the controller further includes a read/write unit, responsive to the subsequent receipt of a read request and a write request, for reading data stored in the storage devices and writing data in the storage devices, a logical volume management unit for mapping between a logical image of the data storage of a host processor (logical volume) and an actual space in the storage devices, a volume management unit for managing an active primary production volume (P-VOL) and second multiple mirror volumes (S-VOL) created as mirror images of the primary volume, and an S-VOL restoring unit for restoring the data of a first S-VOL with the data of a second S-VOL depending on the type of an error that happens in the first S-VOL.
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1-12. (canceled). 13. A computer connected to a storage device which has a storage region and a controller comprising: a processor; an input section; and a port to connect the computer to the storage device, wherein the processor sends to the storage device via the port, based on information input via the input section, information designating, in the storage regions (volumes) of the storage device, one or a plurality of volumes (volume group) in which is stored a copy of data stored in any of the volumes, and information designating attributes of the respective volumes included in the volume group. 14. A computer according to claim 13, wherein the attribute is information which relates to access to the volume, and includes write inhibit or read/write permission information. 15. A computer according to claim 14, wherein the processor, at a time an error occurs in a volume included in the volume group, further sends to the storage device information relating to a number of volumes to be alternatives of the volume where an error has happened. 16. A computer according to claim 15, wherein the processor receives a notice that an error has happened from the storage device via the port. 17. A computer according to claim 15, wherein the processor sends a command instructing restoration of the volume in which error has happened in the storage device via the port to the storage device. 18. A computer according to claim 15, wherein the processor sends a command to inquire an attribute of a volume included in the volume group to the storage device. 19. A computer according to claim 15, wherein the processor, based on an instruction input from the input section, sends to the storage device via the port an instruction to change a structure of the storage device. 20. A management computer connected to a storage device which has a storage region and a controller comprising: a processor; an input section; and a port to connect the management computer to the storage device, wherein the processor sends to the storage device via the port, based on information input via the input section, a command containing information designating, in the storage regions (volumes) of the storage device, one or a plurality of volumes (volume group) in which is stored a copy of data stored in any of the volumes, and information designating attributes of the respective volumes included in the volume group, wherein the command has a field designating attributes of the respective volumes included in the volume group, and a field designating, at a time an error occurs in a volume included in the volume group, a number of volumes to be alternatives of the volume in which the error has occurred, wherein the attribute is information which relates to access to the volume, and includes write inhibit or read/write permission information.
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CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority upon Japanese Patent Application No. 2003-343478 filed on Oct. 1, 2003, which is herein incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data I/O system and a method of controlling the data I/O system, and specifically relates to a technology to ensure availability of a secondary mirror volume in which a copy of data of a primary volume is written. 2. Description of the Related Art Recently, storage systems that manage rapidly increasing data assets have played a vital role in an enterprise information infrastructure. In an increasing social demand for the storage like this, the storage system requires very high availability such that 24-hour-a-day, 365-day-a-year nonstop safety operations are possible. Therefore, the recent storage systems have adopted various technologies to improve the availability of the main transaction processing, such as a mechanism to backup data and a mechanism (replication) to copy data for data analysis or development/testing with no impact on main transaction processing (for example, see U.S. Pat. No. 6,101,497). In the above replication, data stored in a volume (primary volume) applied to main transaction processing is copied to another volume (secondary mirror volume), and this secondary mirror volume is used in various secondary transaction processing such as data backup, data analysis, and development/testing. Thus, it is possible to minimize the influence of the secondary transaction processing on the main transaction processing, which also improves the availability of the main transaction processing. The aforementioned replication technology can basically improve the availability of the primary volume used in the main transaction processing but does not take into consideration availability of the secondary mirror volume. However, actual transaction processing often requires the availability of the secondary mirror volume used in the secondary transaction processing. For example, a content of the secondary mirror volume is sometimes corrupted by a bug inherent in a program, a hardware error, and the like in the transaction processing such as data analysis and development/testing. In such a case, a mechanism is required to simply and quickly recover the secondary mirror volume. In recovery of the secondary mirror volume, the content of the secondary mirror volume is not always restored to an expected content even if data of the primary volume is copied to the secondary mirror volume. The content of the primary volume at the time of copying could have been already updated, and the content after restored does not always agree with the content of the secondary mirror volume before corrupted. SUMMARY OF THE INVENTION The present invention provides a data I/O system which can ensure the availability of a secondary mirror volume in which a copy for data of a primary volume is written and provides a method of controlling the data I/O system. An embodiment of the present invention is a data I/O system including: a plurality of storage devices; and a controller which controls the storage devices. In the data I/O system, the controller further includes: read/write unit, responsive to the subsequent receipt of a read request and a write request, for reading data stored in the storage devices and writing data in the storage devices; logical volume management unit for mapping between a logical image of the data storage of a host processor (logical volume) and an actual space in the storage devices; volume management unit for managing an active primary production volume (P-VOL) and second multiple mirror volumes (S-VOL) created as mirror images of the primary volume; and S-VOL restoring unit for restoring the data of a first S-VOL with the data of a second S-VOL depending on the type of an error that happens in the first S-VOL. The storage devices are, for example, disk drives (hard disk devices). The data I/O system is, for example, a disk array system which accepts access requests sent from the data processing system, and writes data in the disk drives and reads data stored in the disk drives according to the access requests. The I/O data system of the present invention restores the data of a first S-VOL with the data of a second S-VOL depending on the type of an error that happens in the first S-VOL. The recovery of S-VOLs are not always performed by a unique method, but performed according to an error type. Therefore, it is possible to efficiently recover S-VOLs by a flexible method. Examples of the error type are data errors, that is, a case where data is corrupted in terms of software and hardware errors caused by hardware failures of disk drives. There are various restoration methods according to the attribute (read-only (RO), read-and-writable (RW), etc.) of an S-VOL where an error has happened, including: a method of copying data of a RO S-VOL to the S-VOL where an error has happened; a method of replacing the S-VOL where an error has happened with a RO S-VOL; and a method of recovering a read-and-writable S-VOL by storing updates that have occurred in the RW S-VOL since a P-VOL and the RW S-VOL were separated in an increments-volume and replacing it with the RO S-VOL that has updated by data of the increments-volume. Furthermore, in the case of drive errors, a storage device where an error has happened is replaced, and the S-VOL is formed with another storage device normally operating. This enables the S-VOL to be recovered without changing the identification (for example, logical volume ID (LID)) thereof. Features and objects of the present invention other than the above will become clear by reading the description of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawing wherein: FIG. 1 is a schematic view showing an example of the hardware configuration of a storage system; FIG. 2 is a block diagram showing an example of the hardware configuration of a host adapter (HA) 210; FIG. 3 is a block diagram showing an example of the hardware configuration of a storage adapter (SA) 230; FIG. 4 is a block diagram showing an example of the hardware configuration of a management adapter (MA) 220; FIG. 5 is a block diagram showing an example of the hardware configuration of a management server 110; FIG. 6 is a block diagram showing an example of the main software configuration of the storage system; FIG. 7 is a view showing an example of a copy source-destination management table 700; FIGS. 8A to 8C are views of data format examples of an S-VOL group operation command, an S-VOL group initialization command, and a restore command, respectively; FIG. 9 is a view showing an example of an S-VOL group management table 900; FIG. 10 is a flowchart illustrating an example of an S-VOL group initialization process; FIGS. 11A to 11C are views of data format examples of an S-VOL operation command, an S-VOL initialization command 1150-1, and a restore command 1150-2, respectively; FIG. 12 is a view showing an S-VOL management table 1200; FIG. 13 is a view showing an increments management table 1300; FIG. 14 is a flowchart illustrating an example of an S-VOL initialization process; FIG. 15 is a flowchart illustrating an example of a read process; FIG. 16 is a flowchart illustrating an example of a read error process; FIG. 17 is a flowchart illustrating an example of an S-VOL read error process; FIG. 18 is a flowchart illustrating an example of a write process; FIG. 19 is a flowchart illustrating an example of an increments write process; FIG. 20 is a flowchart illustrating an example of a write error process; FIG. 21 is a flowchart illustrating an example of an S-VOL write error process; FIG. 22 is a flowchart illustrating an example of a restore process; FIG. 23 is a flowchart illustrating an example of a restore command setting process; and FIG. 24 is a flowchart illustrating an example of an S-VOL restore process. DETAILED DESCRIPTION OF THE INVENTION At least the following matters will be made clear by the explanation in the present specification and the description of the accompanying drawings. ===Hardware Configuration=== FIG. 1 shows an example of the hardware configuration of a storage system to be described as an embodiment. The storage system includes servers 100 (100-1, 100-2) as data processing systems, a disk control system 200 as a data I/O system, and a management server 110, which are connected so as to communicate with each other. For example, Ethernet (trade mark) is used as a physical protocol of the communication. The disk control system 200 is connected to the servers 100 (100-1, 100-2) and receives data read/write requests issued from the servers 100 (100-1, 100-2). The data read/write requests are also referred to as data input/output requests. The disk control system 200 includes a number of disk drives 240 (240-1 to 240-5) as storage devices. The disk control system 200 reads data stored in the disk drives 240 (240-1 to 240-5) and writes data in the disk drives 240 (240-1 to 240-5) according to the data input/output requests (access requests) issued from the servers 100 (100-1, 100-2). The disk drives 240 (240-1 to 240-5) supply physical storage regions (hereinafter, referred to as physical volumes) provided for the servers 100 (100-1, 100-2). The disk control system 200 manages the storage regions in terms of a logical volume as a unit (hereinafter, also referred to as LU (logical unit)) which is a logical storage region composed of a physical volume. For example, the servers 100 (100-1, 100-2) can identify a storage region on the disk drives 240 (240-1 to 240-5) to which data is written or from which data is read by specifying a logical volume. Note that the disk drives 240 (240-1 to 240-5) may be integrated with the disk control system 200 as shown in FIG. 1 (for example, accommodated in a same enclosure as that accommodating the disk control system 200), or may be separated from the disk control system 200 (for example, accommodated in a different enclosure from that accommodating the disk control system 200). The servers 100 (100-1, 100-2) are computers each including a CPU (Central Processing Unit), a memory, and an I/O device. The servers 100 (100-1, 100-2) provide various services for other computers that access the servers 100. Examples of the services are on-line services such as bank's automated teller services and Internet homepage browsing services, batch services executing experimental simulation in a science and technology field, and the like. Communication between the servers 100 (100-1, 100-2) and the disk control system 200 can be performed according to various protocols. Examples thereof are Fibre Channel, SCSI (Small Computer System Interface), FICON (Fibre Connection) (trade mark), ESCON (Enterprise System Connection) (trade mark), ACONARC (Advanced Connection Architecture) (trade mark), FIBARC (Fibre Connection Architecture) (trade mark), TCP/IP (Transmission Control Protocol/Internet Protocol), and the like. In this communication, several communication protocols can be used among these protocols. For example, when the servers 100 (100-1, 100-2) are mainframes, FICON, ESCON, ACONARC, and FIBER are used. When the servers 100 (100-1, 100-2) are open servers, for example, Fibre Channel, SCSI, and TCP/IP are used. The servers 100 (100-1, 100-2) may request data to be read or written in blocks, each block being a data access/storage unit in the logical volumes, or in files by specifying a file name. In other words, the disk control system 200 may offer a fixed-size block interface abstraction and can be made to serve as a NAS (Network Attached Storage) which provides a file interface. The disk control system 200 includes the disk drives 240 (240-1 to 240-5) as magnetic disk devices, host adapters (HA) 210 (210-1, 210-2), a storage adapter (SA) 230, a management adapter (MA) 220, and an interconnect network 250, as components. The HAs 210 (210-1, 210-2) provide a function to communicate with the servers 100 (100-1, 100-2). The SA 230 provides a function to communicate with the disk drives 240 (240-1 to 240-5). Among these components, the HAs 210 (210-1, 210-2) are sometimes referred to as channel adapters, and the SA 230 is sometimes referred to as a disk adapter. The interconnect network 250 connects the HAs 210 (210-1, 210-2), the SA 230, and the MA 220 to each other such that these adapters can communicate with each other. The interconnect network 250 is composed of a high-speed crossbar switch, and the like. The interconnect network 250 is sometimes connected to a cache memory as a buffer transmitted between the HAs 210 (210-1, 210-2) and the SA 230. In some cases, the HAs 210 (210-1, 210-2), the SA 230, and the MA 220 are constructed as individual modular units so as to be attached to the enclosure of the disk control system 200, or two or more of these adapters are sometimes combined to be integrated as a single unit. Next, a detailed description will be given of each component of the disk control system 200. FIG. 2 shows an example of the hardware configuration of the HAs 210 (210-1, 210-2). Each HA 210 (210-1, 210-2) includes a communication interface 211, a local memory 212, a non-volatile memory 213 composed of a flash memory or the like, a microprocessor 214, and an I/O processor 215. The communication interface 211 performs a process related to communication with the servers 100 (100-1, 100-2). The microprocessor 214 executes programs stored in the local memory 212 to perform various processes of this HA 210 (210-1, 210-2). The I/O processor 215 implements high-speed data transfer between the HA 210 (210-1, 210-2) and the SA 230 or the cache memory (not shown). These components are connected to each other through a bus 216. The non-volatile memory 213 stores microprograms which are software to implement the various processes that the HA 210 (210-1, 210-2) offers. The microprograms are properly loaded into the local memory 212 and executed by the microprocessor 214. For example, a DMA (Direct Memory Access) processor is used for the I/O processor 215. FIG. 3 shows an example of the configuration of the SA. 230. The SA 230 includes an I/O processor 231, a local memory 232, a non-volatile memory 233 composed of a flash memory or the like, a microprocessor 234, and a disk controller 235. The I/O processor 231 implements data transfer between the SA 230 and the HAs 210 (210-1, 210-2). The microprocessor 234 executes programs stored in the local memory to perform various processes of the SA 230. The disk controller 235 writes data in the disk drives 240 (240-1 to 240-5) and reads data stored in the disk drives 240 (240-1 to 240-5). These components are connected to each other through a bus 236. The non-volatile memory 233 stores microprograms which are software to implement the various processes that the SA 230 offers. The microprograms are properly loaded into the local memory 232 and executed by the microprocessor 234. For example, a DMA processor is used for the I/O processor 231. The SA 230 processes data read/write requests received by the HAs 210 (210-1, 210-2). The disk drives 240 (240-1 to 240-5) are connected to the SA 230. The SA 230 reads data stored in the disk drives 240 (240-1 to 240-5) and writes data in the disk drives 240 (240-1 to 240-5). The disk drives 240 (240-1 to 240-5) provide physical volumes (PD0 to PD4) constituting secondary mirror volumes (LV0 to LV2) to be described later. The disk controller 235 may control the disk drives 240 (240-1 to 240-5) with a RAID system (for example, RAID0, RAID1, or RAID5). FIG. 4 shows an example of the hardware configuration of the MA 220. The MA 220 includes a microprocessor 221 and a memory 222. The MA 220 is communicably connected to the HAs 210 (210-1, 201-2) and the SA 230 through the interconnect network 250 by an internal communication interface 223. The microprocessor 221 and the memory 222 are connected to each other through a bus 235. The MA 220 performs various settings for the HAs 210 (210-1, 210-2) and the SA 230, monitoring of various errors in the disk control system 200, and the like. The MA 220 can collect information on processing loads of each HA 210 (210-1, 210-2) and the SA 230. Examples of the information on the processing load are a utilization of the microprocessor 221, a frequency of accesses to each logical volume, and the like. These pieces of information are collected and managed based on a program executed in the HAs 210 (210-1, 210-2) and the SA 230. The MA 220 performs a process according to a setting command received by the HAs 210 (210-1, 210-2). Moreover, the MA 220 passes a notification command to be sent to the management server 110 to the HAs 210 (210-1, 210-2) through the interconnect network 250. FIG. 5 shows an example of the hardware configuration of the management server 110. The management server 110 includes a CPU 111, a memory 112, a port 113, a storage media reading device 114, an input device 115, an output device 116, and a storage device 117. The CPU 111 controls the entire management server 110. The CPU 111 executes programs stored in the memory 112 to implement various processes offered by the management server 110. The storage media reading device 114 reads programs and data recorded in the storage medium 118. The read programs and data are stored in the memory 112 or the storage device 117. Accordingly, for example, a program recorded in the storage medium 118 can be read from the storage medium 118 using the storage media reading device 114 and stored in the memory 112 or the storage device 117. As the storage medium 118, a flexible disk, CD-ROM, DVD-ROM, DVD-RAM, a semiconductor memory, and the like can be used. The storage device 117 is, for example, a hard disk device, a flexible disk device, a semiconductor storage device, or the like. The input device 115 is used by an operator or the like for input of data to the management server 110 and the like. For example, a keyboard, a mouse, or the like is used as the input device 115. The output device 116 outputs information to the outside. For example, a display, printer, or the like is used as the output device 116. The port 113 is used for, for example, communication with the disk control system 200, and the management server 110 can communicate with the HAs 210 (210-1, 210-2), the SA 230, and the like through the port 113. A manager of the storage system or the like can make, for example, various settings related to the disk drives 240 (240-1 to 240-5) by operating the management server 110. Examples of the various settings related to the disk drives 240 (240-1 to 240-5) are addition and removal of a disk drive, modification of the RAID structure (for example, change from RAID1 to RAID5), and the like. With the management server 110, operations such as checking an operation state of the storage system and identifying an error unit can be performed. The management server 110 is connected to an external maintenance center by LAN, a telephone line, or the like. Using the management server 110, it is possible to monitor errors of the storage system and quickly deal with errors when happened. The occurrence of errors is notified by, for example, operating systems, applications, driver software, and the like which are running in the servers 100 (100-1, 100-2) and the management server 110. The notification is made through the HTTP protocol, the SNMP (Simple Network Management Protocol), E-mails, or the like. The various settings and controls for the management server 110 can be performed by use of Web pages provided by a Web server running in the management server 110. Next, a description will be given of the software configuration of the storage system. FIG. 6 shows an example of software configuration of the storage system of this embodiment. Processes of each unit shown in this drawing is implemented by hardware corresponding to the unit or a program executed by the hardware. Moreover, various tables shown in FIG. 6 are stored and managed by the hardware corresponding to the unit or a program executed by the hardware. ===Copy Management=== First, a description will be given of a copy management process performed by the SA 230. The copy management process is implemented by a program stored in the non-volatile memory 233 to implement the copy management process, the program being executed by the microprocessor 234 of the SA 230. In the embodiment, an S-VOL management unit 630 shown in FIG. 6 provides the copy management process. The copy management indicates that, when data is written in a logical volume (hereinafter, referred to as a copy source logical volume), the same data is also written in another logical volume (hereinafter, referred to as a copy destination logical volume) different from the copy source logical volume to store a copy for data stored in a logical volume into another logical volume. In the operational mode of a general storage system, the copy source logical volume is set as a volume (primary volume) directly used in main transaction processing, and the copy destination logical volume is set as a volume (second mirror volume) to manage the copy for the primary volume. Note that this embodiment is assumed to also employ such settings. As previously described, the manager of the storage system or the like operates the management server 110 to set mapping between copy source logical volumes and copy destination logical volumes. FIG. 7 shows an example of a copy source-destination management table 700 which manages the mapping between the copy source logical volumes and the copy destination logical volumes. In the copy source-destination management table 700, the logical volume IDs (LUNs (Logical Unit Numbers)) of the copy source logical volumes are made to correspond to the respective LUNs of the copy destination logical volumes. In the copy management process, a control is performed such that, when data is written in the copy source logical volume, the data is also written in the copy destination logical volume. In the above control method, a synchronous mode and an asynchronous mode are available in some cases. In the synchronous mode, when data is written in the copy source logical volume, completion of writing is reported to the data processing system after the data is written in both the copy source and destination logical volumes. In other words, in the synchronous mode, the completion is not reported to the data processing system until the writing into both the copy source and destination logical volumes is completed. Accordingly, the synchronous mode ensures the identity between contents of the copy source and destination logical volumes with high reliability, but correspondingly reduces the speed of the response to the data processing system. On the other hand, in the asynchronous mode, when data is written in the copy source logical volume, completion of the writing is reported to the data processing system independently of whether the data has been written in the copy destination logical volume. Accordingly, in the asynchronous mode, the response to the data processing system is quick, but the identity between the copy source and destination logical volumes is not necessarily ensured. In the copy management process, the relationship of a pair of the copy source logical volume and the copy destination logical volume is properly shifted between two states, a “paired state” and a “split state”. The “paired state” is controlled so as to ensure the identity between data of the copy source and destination logical volumes in real time. Specifically, when data is written in the copy source logical volume, the same data is also written in the copy destination logical volume by the aforementioned synchronous or asynchronous mode. On the other hand, the “split state” is a state where the above control to ensure the identity in real time is released. Shift from the “paired state” to the “split state” is referred to as “split”. On the contrary, shift from the “split state” to the “paired state” is referred to as “resync.”The shift from the “paired state” to the “split state” is, for example, performed for the purpose of the second transaction processing such as acquiring a backup of data of a primary volume; or using data of a main transaction processing for development or testing. For example, to acquire the backup of data, data in the copy destination logical volume is backed up to a storage medium such as a cartridge tape after the “paired state” is shifted to the “split state”. For example, when data of the main transaction processing is desired to be used for development or testing, data in the copy destination logical volume is used for the development or testing after the “paired state” is shifted to the “split state”. Since the secondary transaction processing such as backup is performed in a state shifted to the “split state” in such a manner, the influence on the main transaction processing due to the second transaction processing other than the main transaction processing can be suppressed as much as possible. In the case where a pair in the “split state” is “resynced” into the “paired state” after the completion of secondary transaction processing and the like, it is required to reflect updates that have occurred in the copy source logical volume since the pair is “split” on the copy destination logical volume. The update increments during this period are stored in a logical volume, for example, in blocks, which is hereinafter referred to as an increments-volume. When a pair is “resynced”, first, the content of the increments-volume is reflected on the copy destination logical volume, and then the pair is shifted to the “paired state”. ===S-VOL group=== Next, a description will be given of an S-VOL group. At least a secondary mirror volume (S-VOL) belongs to each S-VOL group. The S-VOL group properly contains a spare S-VOL and an increments-volume. The spare S-VOL stores data of the S-VOL after a time of aforementioned “split”. In the spare S-VOL, the attribute is set to forbid data read/write accesses by the servers 100 (100-1, 100-2). The increments-volume stores increments data due to update performed in S-VOLs after a certain point of time. FIG. 8A shows the data format of an S-VOL group operation command to perform settings and operations related to an S-VOL group. The S-VOL group operation command is sent and received by the management server 110 and the SA 230, respectively. In FIG. 8A, a command ID which is an identification indicating a type of the command is set in a command ID field 820. In a command specific field 830, parameters and the like depending on the types of the command are set. The types of command are an S-VOL group initialization command to initialize an S-VOL; a restore command to restore data of an S-VOL where a data error has happened into the data content before the data error has happened; a query command to query the current attribute of the specified spare S-VOL or S-VOL; and the like. In the command ID field 820, a command ID (0: S-VOL initialization, 1: restore, 3: query (S-VOL attribute/spare S-VOL attribute)) corresponding to each command is set. As an example, FIG. 8B shows the data format of the S-VOL group operation command in the case where the command is the S-VOL group initialization command. In FIG. 8B, a group ID which is an identification of an S-VOL group to be initialized is set in a group ID field 831. Each of S-VOL attribute lists 832 includes: a field 834 where an ID (LID) (hereinafter, referred to as S-VOL ID) of each S-VOL belonging to the S-VOL group to be initialized is set; and a field 835 where the attribute of each S-VOL is set. Types of the attribute are attributes “Read-Only (RO)” and “Read-Write (RW)”. The “RO” restricts accesses to the S-VOL to only read accesses to data. The “RW” allows write accesses to data. When the S-VOL has an attribute of “Read-Only (RO)”, “RO” is set in the field 834, and when the S-VOL has an attribute of “Read-Write (RW)”, “RW” is set in the field 834. For example, the attribute of an S-VOL used for reference like in transaction processing such as backup, archive, and OLAP (Online Analytical Processing) is set to “RO”. On the contrary, the attribute of an S-VOL used in a situation where data could be written, such as development and testing, is set to “RW”. The S-VOL group initialization command includes the S-VOL attribute lists 832 as much as the number of S-VOLs belonging to the S-VOL group to be initialized. In FIG. 8B, the number of spare S-VOLs set for the S-VOL group of interest is set in a number of spare S-VOLs field 833. FIG. 8C shows the data format of the S-VOL group operation command in the case where the command is the restore command. The restore command 810-2 includes: a field 836 where an ID (referred to as an LID) of an S-VOL to be restored is set; and a field 837 where blocks (referred to as BIDS) to be restored are set. ===S-VOL Group Initialization=== Next, a description will be given of a process to initialize an S-VOL group, which is performed according to the aforementioned S-VOL group initialization command issued from the management server 110 to the SA 230. As an example, the following description will be given of a case where S-VOLs (LIDS=LI0 to LI2) having the same data content as that of the same primary volume are initialized as an S-VOL group with a group ID of G0. FIG. 9 shows an S-VOL group management table 900 managed in the MA 220. FIG. 10 shows a flowchart illustrating an S-VOL group initialization process. In FIG. 10, first, an S-VOL group setting unit 610 of the management server 110 sends the S-VOL group initialization command 810-1 shown in FIG. 8B to an S-VOL group management unit 620 of the MA 220 (S1010). The S-VOL group management unit 620 receives the S-VOL group initialization command 810-1 (S1020). The S-VOL group management unit 620 of the MA 220 sets the contents of the S-VOL group management table 900 based on the received S-VOL group initialization command 810-1 (S1021). Herein, when the S-VOL attribute lists 832 of the S-VOL group initialization command 810-1 include an S-VOL (RW S-VOL) with an attribute specified to “RW”, the S-VOL group management unit 620 sets a logical volume (increments-volume) DLV2 to store update increments of the RW S-VOL. In the example of FIG. 9, the content of a cell in a logical region attribute column 903, which corresponds to the increments-volume (LID=DLV2) at the bottom cell in a logical volume ID column 902, is set to “RW”. In the S-VOL group management table 900, an ID of a logical volume used for recovery of the S-VOL is set in a corresponding cell in a recovery logical volume ID (recovery LID) column 905. For example, the recovery LID of an S-VOL with an attribute of “RW” is set to the ID of an increments-volume used for recovery of that S-VOL. The S-VOL group management unit 620 sets spare S-VOLs as much as the value set in the number-of-spare S-VOLs field 833 of the S-VOL group initialization command 810-1 shown in FIG. 8B for the S-VOL group G0. The contents of the S-VOL management table 900 are set in such a manner. The S-VOL group management unit 620 then assigns physical volume regions (PD0 to PD4) to the respective volumes of S-VOLs (LIDs=LV0 to LV2), an increments-volume (LID=DVL2), and a spare S-VOL (LID=S0) based on the above S-VOL group management table 900 whose contents have been set (S1022). Subsequently, the S-VOL group management unit 620 sends a reply for the S-VOL group initialization command 810-1 to the S-VOL group setting unit 610 (S1023) and sends an S-VOL initialization command 1150-1 to an S-VOL management unit 630 of the SA 230 (S1024), which processes read/write accesses to logical volumes. FIG. 11A shows a data format of the S-VOL operation command. A command ID (0: S-VOL initialization, 1: PID change, 2: query (attribute/PID/access frequency), 3: restore) indicating a type of command is set in the S-VOL operation command. The command with “0: S-VOL initialization” is a command to initialize an S-VOL. The command with “1: PID change” is a command to change a physical volume of a specified S-VOL. The command with “2: query (attribute/PID/access frequency)” is a command to query the attribute, the physical volume ID, and the access frequency of a specified S-VOL or spare S-VOL. The command with “3: restore” is a command to restore data of specified blocks (BIDS) of a specified S-VOL (LID) with reference to a specified RLID. A command specific field with contents depending on the types of command is set in a field 1170. FIG., 11B shows the data format of the S-VOL initialization command. The S-VOL initialization command 1150-1 includes: a field 1171 where the command ID is set; and a field 1172 where volume lists are set. Each volume list is a combination of the (logical) volume ID, the attribute, and the physical volume ID of each of S-VOLs, a spare S-VOL, and an increments-volume. FIG. 11C shows the data format of the restore command 1150-2. The restore command 1150-2 includes: a field 1178 where an S-VOL ID is set; a field 1179 where blocks to be restored are set; and a field 1180 in which a recovery LID referred to for restoring(recovering) is set. ===S-VOL Initialization=== Next, a description will be given of a process related to initialization of an S-VOL, which is performed between the S-VOL group management unit 620 of the MA 620 and the S-VOL management unit 630 of the SA 230. FIGS. 12 and 13 show an S-VOL management table 1200 managed by the SA 230 and an increments management table 1300 managed by the SA 230, respectively. FIG. 14 shows a flowchart illustrating the S-VOL initialization process. In FIG. 14, first, the S-VOL group management unit 620 sends the S-VOL initialization command 1150-1 to the S-VOL management unit 630 (S1024). The S-VOL management unit 630 receives the S-VOL initialization command 1150-1 (S1400). The S-VOL management unit 630 then sets the logical volume IDS, the logical volume attributes, the physical volume IDs, and the recovery logical volume IDS in the S-VOL management table 1200 based on the volume lists 1172 included in the S-VOL initialization command 1150-1 (S1401). The S-VOL management table 1200 is created for each S-VOL group. As shown in FIG. 12, the S-VOL management table 1200 manages frequencies of accesses 1205 to respective logical volumes in addition to the logical volume IDs 1201, the logical volume attributes 1202, the physical volume IDS 1203, and the recovery logical volume IDS 1204. Note that the access frequencies are measured by the SA 230. An S-VOL read/write process unit 640 of the SA 230 adds “1” to a cell in the access frequency column 1205 of the S-VOL management table 1200 each time processing the read/write access to an S-VOL or spare S-VOL. The S-VOL group management unit 620 of the MA 220 sends the S-VOL operation command 1150 (command ID=2) where the LID of an S-VOL targeted for query is set to the S-VOL management unit 630 of the SA 230 to be able to acquire the access frequency of the S-VOL of interest. The S-VOL group management unit 620 selects an S-VOL to be used for recovery based on the acquired access frequencies. The S-VOL management unit 630 judges whether the attribute of the S-VOL to be restored is “RW” (S1402). When the attribute of the S-VOL of interest is “RW”, the recovery volume ID is registered in the increments management table 1300 (S1403). The increments management table 1300 manages block IDs of updated blocks for each registered increments-volume. The S-VOL management unit 630 then judges whether any volume list 1172 remains unprocessed (S1404). If any volume list 1172 remains unprocessed, the S-VOL management unit 630 proceeds to S1401, and if not, the S-VOL management unit 630 returns a reply to the S-VOL group management unit 620 (S1405). ===Read Process=== FIG. 15 shows a flowchart illustrating a read process among processes performed by the S-VOL read/write process unit 640. First, the S-VOL read/write process unit 640 receives a read request for an S-VOL which is sent from the HA 210 (S1500). The S-VOL read/write process unit 640 then reads data from the S-VOL (for example, S-VOL with LID=LV0) set in the above read request (S1501). The SA 230 is monitoring in real time whether an error happens in the disk drives 240. In S1502, if no drive error is detected (S1502: NO), the SA 230 adds 1 to the access frequency of the S-VOL with no drive error detected in the S-VOL management table 1200 (S1503). In S1504, the S-VOL read/write process unit 640 returns a replay for the read request to the HA 210. Upon detecting the read error in S1502, the S-VOL read/write process unit 640 notifies an S-VOL error process unit 650 that the read error is detected (1510). Upon receiving the notification, the S-VOL error process unit 650 executes a read error process shown in a flowchart of FIG. 16. This process will be described later. Subsequently, the S-VOL read/write process unit 640 receives a result of the read error recovery from the S-VOL error process unit 650 and judges whether the recovery is successful (S1511). When the recovery is successful, the S-VOL read/write process unit 640 re-executes the read access to the S-VOL where the read error has happened (S1512), adds 1 to the access frequency of the S-VOL in the S-VOL management table 1200 (S1503), and returns a reply for the read request to the HA 210 (S1504). When the recovery is unsuccessful as a result of the judgment in S1511, the S-VOL read/write process unit 640 returns a read failure as a reply for the read request to the HA 210 (S1504). ===Read Error Process=== FIG. 16 shows a flowchart illustrating the process (read error process) related to read errors, which is performed between the S-VOL group management unit 620 and the S-VOL error process unit 650. Upon receiving the read error notification sent from the S-VOL read/write process unit 640 (S1510), the S-VOL error process unit 650 sends the LID of the S-VOL where the read error has happened to the S-VOL group management unit 620 (S1610). Upon receiving the read error notification from the S-VOL error process unit 650 (S1600), the S-VOL group management unit 620 executes a read error process S1700 (S1601), and then sends a recovery result of execution of the read error process S1700 to the S-VOL error process unit 650 (S1602). Upon receiving the recovery result (S1611), the S-VOL error process unit 650 judges whether the recovery is successful (S1612). When the recovery is unsuccessful as a result of the judgment, the S-VOL error process unit 650 notifies the S-VOL read/write process unit 640 that the recovery is unsuccessful (S1613). On the contrary, when the recovery is successful in the judgment of S1612, the S-VOL error process unit 650 replaces a physical volume constituting the S-VOL where the error has happened based on the recovery result received from the S-VOL group management unit 620 (S1620). Furthermore, the S-VOL error process unit 650 judges whether the physical volume is a physical volume of another S-VOL (S1621). When the physical volume of interest is a physical volume of another S-VOL, the LID of this S-VOL is set as the recovery LID of the S-VOL where the error has happened (S1622). When the physical volume of interest is a physical region of a spare S-VOL, the spare S-VOL is deleted from the S-VOL management table 1200 (S1623). The S-VOL error process unit 650 notifies the S-VOL read/write process unit 640 that the recovery is successful (S1624). In such a manner, when the type of error is a drive error, the disk control system 200 of this embodiment replaces a physical volume constituting the S-VOL where the error has happened and forms the S-VOL with another physical volume normally operating. Therefore, the S-VOL can be recovered from the hardware error without changing the S-VOL LUN. FIG. 17 shows a flowchart illustrating the S-VOL read error process S1700 executed in S1601 of FIG. 16. First, the S-VOL group management unit 620 judges the presence of a spare S-VOL (S1701). When the spare S-VOL is present, the S-VOL group management unit 620 changes the physical volume ID (PID) of the S-VOL where the error has happened to the physical volume ID of the spare S-VOL (S1710), and deletes the spare S-VOL ID from the S-VOL management table 1200 (S1711). On the contrary, when a spare S-VOL is not present in S1701, the S-VOL group management unit 620 judges the presence of an S-VOL with an attribute of “RO” (S1702). Herein, when no S-VOL with an attribute of “RO” is present in S1701, the S-VOL group management unit 620 returns a read error notification (S1703). On the contrary, when the S-VOLs with an attribute of “RO” are present, the S-VOL group management unit 620 queries the S-VOL error process unit 650 for the access frequencies of the S-VOLs with an attribute of “RO” (S1704). The S-VOL group management unit 620 selects an S-VOL with the lowest access frequency (Freq) in the S-VOL management table 1200 (S1705), and changes the physical volume ID of the S-VOL where the error has happened to the physical volume ID of the selected S-VOL (S1706). Furthermore, the S-VOL group management unit 620 registers the ID of the logical volume selected as a logical volume for recovery of the S-VOL where the error has happened in the S-VOL management table 1200 (S1707). ===Write Process=== FIG. 18 shows a flowchart illustrating a write process executed by the S-VOL read/write process unit 640. Upon receiving a write request for an S-VOL from the HA 210 (S1800), the S-VOL read/write process unit 640 of the SA 230 judges whether the attribute of the S-VOL set in the write request is “D-RW (increments write)” (S1801). When the attribute is “D-RW” as a result of the judgment, the S-VOL read/write process unit 640 executes an increments write process S1900 shown in FIG. 19 (S1802). The increments write process S1900 will be described later. On the contrary, when the attribute is not “D-RW” as a result of the judgment, namely, when the attribute is “RW”, the S-VOL read/write process unit 640 executes normal writing (S1810). The S-VOL read/write process unit 640 judges whether a write error has happened on the execution of normal writing (S1811). When the write error has not happened as a result of the judgment, the S-VOL read/write process unit 640 adds 1 to the access frequency (Freq) in the S-VOL management table 1200 and returns a reply (reply indicating the success of writing) for the write request to the HA 210 (S1812). On the contrary, when the write error has happened in the judgment of S1811, the S-VOL read/write process unit 640 notifies the S-VOL error process unit 650 that the write error has happened (S1820). Upon receiving a result of the write error recovery from the S-VOL error process unit 650, the S-VOL read/write process unit 640 then judges whether the recovery is successful (S1821). When the recovery is successful, the process proceeds to (S1801). When the recovery is unsuccessful, the S-VOL error process unit 650 returns a reply (reply indicating the write failure) for the write request to the HA 210 (S1822). FIG. 19 shows a flowchart illustrating the increments write process. In the increments write process, first, the S-VOL read/write process unit 640 judges whether a block ID is registered in a write destination block ID field 1352 for the logical volume ID (LID) of the S-VOL to which data is to be written in the increments management table 1300, namely, judges whether the S-VOL has been updated (S1901). Herein, when no block ID is registered in the field 1352 of the write destination block ID, the S-VOL read/write process unit 640 registers the write destination block ID field 1352 in the increments management table 1300 (S1902). The S-VOL read/write process unit 640 then reads data written in a block corresponding to the write destination block ID from the S-VOL (S1903), updates the read data with the data to be written, and writes the updated data in the increments-volume (S1904). FIG. 20 shows a flowchart illustrating a write error process performed between the S-VOL group management unit 620 and the S-VOL error process unit 650. Upon receiving the write error notification sent from the S-VOL read/write process unit 640, the S-VOL error process unit 650 sends a notification that the write error has happened to-the S-VOL group management unit 620 (S2010). Upon receiving the write error notification from the S-VOL error process unit 650 (S2000), the S-VOL group management unit 620 executes a write error process S2100 shown in FIG. 21 (S2001). The write error process S2100 will be described later. Subsequently, the S-VOL group management unit 620 sends a recovery result which is a result of execution of the write error process S2100 to the S-VOL error process unit 650 (S2002). The S-VOL error process unit 650 receives the result of the write error recovery from the S-VOL group management unit 620 (S2011). The S-VOL error process unit 650 judges whether the recovery is successful based on the received recovery result (S2012). Herein, when the recovery is judged to be unsuccessful, the S-VOL error process unit 650 notifies the S-VOL read/write process unit 640 of the failure of recovery (S2013). On the contrary, when the recovery is judged to be successful, the S-VOL error process unit 650 replaces the physical volume of the S-VOL where the error has happened based on the recovery result received from the S-VOL group management unit 620 (S2020). Furthermore, the S-VOL error process unit 650 judges whether the physical volume of interest is a physical volume of another S-VOL (S2021). When the physical volume of interest is a physical volume of another S-VOL in the judgment, the S-VOL error process unit 650 changes the attribute thereof to “D-RW” and sets the LID of the S-VOL as the ID (RID) of the S-VOL for recovery of the S-VOL where the error has happened in the S-VOL group management table 900 (S2022). When the physical volume of interest is the physical volume constituting a spare S-VOL in the judgment, the spare S-VOL is deleted from the S-VOL management table 1200 (S2023). The S-VOL error process unit 650 notifies the S-VOL read/write process unit 640 that the recovery is successful (S2024). FIG. 21 shows a flowchart illustrating the aforementioned S-VOL write error process S2100. First, the S-VOL group management unit 620 judges the presence of the spare S-VOL (S2101). When the spare S-VOL is present as a result of the judgment, the S-VOL group management unit 620 changes the physical ID (PID) of the S-VOL where the error has happened to the physical volume ID of the spare S-VOL (S2110) and deletes the ID of the spare S-VOL from the S-VOL management table 1200 (S2111). On the contrary, when no spare S-VOL is present as a result of the judgment (S2101), the S-VOL group management unit 620 judges whether an S-VOL with an attribute of “RO” is present (S2102). When no S-VOL with an attribute of “RO” is present, the write error notification is returned (S2103). On the contrary, when S-VOLs with an attribute of “RO” are present, the S-VOL group management unit 620 queries the S-VOL error process unit 650 for the access frequencies of the S-VOLs with an attribute of “RO” (S2104). The S-VOL group management unit 620 selects an S-VOL with the lowest access frequency in the S-VOL management table 1200 (S2105) and changes the attribute of the S-VOL where the error has happened to “D-RW” and the physical volume ID (PID) to the physical volume ID (PID) constituting the selected S-VOL (S2106), respectively. In such a manner, using the S-VOL with the lowest access frequency can suppress the influence of the process related to the recovery on the transaction processing performed using the other S-VOLs, thus ensuring availability of S-VOLs. Furthermore, the S-VOL group management unit 620 registers the logical volume ID in the RLID field 1204 of the S-VOL management table 1200 (S2107), the logical volume ID being selected in the S-VOL management table 1200 as the recovery LID for the S-VOL where the error has happened. ===Restore=== Next, a description will be given of a process related to restoring of an S-VOL where an error has happened, which is performed between the S-VOL group setting unit 610 and the S-VOL group management unit 620. FIG. 22 shows a flowchart illustrating the process related to restoring which is performed between the S-VOL group setting unit 610 and the S-VOL group management unit 620. First, the S-VOL restore command 850-2 shown in FIG. 8C where the LID of an S-VOL desired to be restored, block IDs desired to be restored, and the like are set is sent from the S-VOL group setting unit 610 of the management server 110 to the S-VOL group management unit 620 (S2200). Upon receiving the restore command 810-2 (S2210), the S-VOL group management unit 620 of the MA 220 executes an S-VOL restore command setting process S2300 (S2211). The S-VOL restore command setting process will be described in detail later. Subsequently, the S-VOL group management unit 620 judges whether setting of the S-VOL restore command 1150-2 is successful (S2212). When the setting is judged to be successful, the S-VOL group management unit 620 sends the restore command 1150-2 to the S-VOL group error process unit 650 (S2213). Moreover, the S-VOL group management unit 620 sends a restore result to the S-VOL group setting unit 610 of the management server 110 (S2214). FIG. 23 shows a flowchart illustrating the aforementioned restore command setting process S2300. This process is performed between the S-VOL group management unit 620 of the MA 220 and the S-VOL error process unit 650 of the SA 230. First, the S-VOL group management unit 620 judges the presence of a spare S-VOL (S2301). When the spare S-VOL is present, the S-VOL management unit 620 sets the recovery LID set in the restore command 1150-2 in a corresponding cell of the LID column 902 in the S-VOL group management table 900 (S2310). On the contrary, when the spare S-VOL is not present, the S-VOL group management unit 620 judges whether an S-VOL with an attribute of “RO” is present (S2302). When no S-VOL with an attribute of “RO” is present, the S-VOL management unit 620 returns a notification that the restoring is unsuccessful (S2303). On the contrary, when S-VOLs with an attribute of “RO” are present, the S-VOL group management unit 620 queries the S-VOL error process unit 650 for the access frequencies of the S-VOLs with an attribute of “RO” (S2304). The S-VOL group management unit 620 selects an S-VOL with a lowest access frequency (Freq) in the S-VOL management table 1200 based on the access frequencies sent as a result of the query (S2305), and sets the recovery LID set in the restore command 1150-2 to the LID of the selected S-VOL (S2306). Using an S-VOL with the lowest access frequency in such a manner can suppress the influence of the process related to the recovery on the transaction processing performed using the other S-VOLS, thus ensuring high availability of S-VOLS. FIG. 24 shows a flowchart illustrating an S-VOL restore process. Upon receiving the restore command 1150-2 from the S-VOL group management unit 620 (S2400), the S-VOL error process unit 650 judges whether the attribute of the S-VOL to be restored, which is set in the restore command 1150-2, is “RW” (S2401). When the attribute is not “RW”, the S-VOL error process unit 650 reads data of blocks set in the restore command 1150-2 from the recovery volume set in the restore command 1150-2 and writes the read data in the S-VOL desired to be restored (S2410). After the completion of this writing, the S-VOL error process unit 650 sends a notification that the restoring is completed (S2404). On the contrary, when the attribute is “RW” in the judgment of S2401, the S-VOL error process unit 650 judges whether the blocks which are desired to be restored and specified by the restore command 1150-2 have been updated with reference to the increments management table 1300 (S2402). When the blocks are not judged to have been updated as a result of the judgment, the process proceeds to S2410. On the contrary, when the blocks are judged to have been updated, the S-VOL error processing unit 650 reads data of the blocks desired to be restored from the increments-volume of the S-VOL desired to be restored and writes the read data in the S-VOL desired to be restored (S2403). After the completion of the writing, the S-VOL error process unit 650 sends the notification that the restoring is completed to the S-VOL group management unit 620 (S2404). According to the present invention, the availability of S-VOLs can be ensured as described above with the embodiment. Moreover, each S-VOL is recovered using another S-VOL or the spare S-VOL. Accordingly, it is possible to recover the S-VOL including necessary contents at a certain point of time, for example, in data analysis, development, testing, and the like. Moreover, the S-VOLs are not always recovered by a uniform method but recovered by a method according to the error type. Accordingly, the S-VOL can be efficiently recovered by a flexible method. In addition, by using the S-VOL with the lowest access frequency as a read-only volume used for the recovery, it is possible to suppress the influence of a process related to recovery on transaction processing performed using the other S-VOLs and thus ensure availability of S-VOLS. Moreover, a logical volume (spare S-VOL) to which read/write accesses are forbidden is used instead of the read only volume used in the above described recovery. Accordingly, it is possible to further suppress the influence of the process related to recovery on transaction processing performed using the other S-VOLs and thus ensure high availability of S-VOLS. Furthermore, in the case of drive errors, a storage device supplying a storage region constituting the S-VOL where an error has happened is replaced, and the S-VOL is formed with another storage device normally operating. Recently, as for disk drives used for S-VOLs and the like, inexpensive drives such as ATA drives are sometimes employed to reduce a data management cost. However, if the frequency of errors is increased by using the inexpensive drives, the maintenance work is increased, and the management cost therefor is increased. To realize reduction in TCO (Total Cost of Ownership) using the inexpensive drives, reduction in management cost is essential. According to this embodiment, the S-VOLs can be efficiently recovered, and the reduction in TCO can be realized using the inexpensive drives. Although the preferred embodiment of the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from spirit and scope of the inventions as defined by the appended claims. According to the present invention, the availability of S-VOLs can be ensured. Moreover, since each S-VOL is recovered using another S-VOL or a spare S-VOL, it is possible to recover the S-VOL including necessary contents at a certain point of time, for example, in data analysis, development, testing, and the like. By using a RO S-VOL with the lowest access frequency as the read-only S-VOL used for the aforementioned recovery, it is possible to suppress the influence of a process related to recovery on transaction processing performed using the other S-VOLs and thus ensure availability of S-VOLs. Furthermore, instead of the read-only volume used in the aforementioned recovery, a logical volume (spare S-VOL) is used which is controlled such that read/write accesses are forbidden is used and the contents of S-VOLs at a certain time are maintained. Accordingly, it is possible to further suppress the influence of the process related to recovery on transaction processing performed using the other S-VOLs and thus ensure high availability of S-VOLS.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates to a data I/O system and a method of controlling the data I/O system, and specifically relates to a technology to ensure availability of a secondary mirror volume in which a copy of data of a primary volume is written. 2. Description of the Related Art Recently, storage systems that manage rapidly increasing data assets have played a vital role in an enterprise information infrastructure. In an increasing social demand for the storage like this, the storage system requires very high availability such that 24-hour-a-day, 365-day-a-year nonstop safety operations are possible. Therefore, the recent storage systems have adopted various technologies to improve the availability of the main transaction processing, such as a mechanism to backup data and a mechanism (replication) to copy data for data analysis or development/testing with no impact on main transaction processing (for example, see U.S. Pat. No. 6,101,497). In the above replication, data stored in a volume (primary volume) applied to main transaction processing is copied to another volume (secondary mirror volume), and this secondary mirror volume is used in various secondary transaction processing such as data backup, data analysis, and development/testing. Thus, it is possible to minimize the influence of the secondary transaction processing on the main transaction processing, which also improves the availability of the main transaction processing. The aforementioned replication technology can basically improve the availability of the primary volume used in the main transaction processing but does not take into consideration availability of the secondary mirror volume. However, actual transaction processing often requires the availability of the secondary mirror volume used in the secondary transaction processing. For example, a content of the secondary mirror volume is sometimes corrupted by a bug inherent in a program, a hardware error, and the like in the transaction processing such as data analysis and development/testing. In such a case, a mechanism is required to simply and quickly recover the secondary mirror volume. In recovery of the secondary mirror volume, the content of the secondary mirror volume is not always restored to an expected content even if data of the primary volume is copied to the secondary mirror volume. The content of the primary volume at the time of copying could have been already updated, and the content after restored does not always agree with the content of the secondary mirror volume before corrupted.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a data I/O system which can ensure the availability of a secondary mirror volume in which a copy for data of a primary volume is written and provides a method of controlling the data I/O system. An embodiment of the present invention is a data I/O system including: a plurality of storage devices; and a controller which controls the storage devices. In the data I/O system, the controller further includes: read/write unit, responsive to the subsequent receipt of a read request and a write request, for reading data stored in the storage devices and writing data in the storage devices; logical volume management unit for mapping between a logical image of the data storage of a host processor (logical volume) and an actual space in the storage devices; volume management unit for managing an active primary production volume (P-VOL) and second multiple mirror volumes (S-VOL) created as mirror images of the primary volume; and S-VOL restoring unit for restoring the data of a first S-VOL with the data of a second S-VOL depending on the type of an error that happens in the first S-VOL. The storage devices are, for example, disk drives (hard disk devices). The data I/O system is, for example, a disk array system which accepts access requests sent from the data processing system, and writes data in the disk drives and reads data stored in the disk drives according to the access requests. The I/O data system of the present invention restores the data of a first S-VOL with the data of a second S-VOL depending on the type of an error that happens in the first S-VOL. The recovery of S-VOLs are not always performed by a unique method, but performed according to an error type. Therefore, it is possible to efficiently recover S-VOLs by a flexible method. Examples of the error type are data errors, that is, a case where data is corrupted in terms of software and hardware errors caused by hardware failures of disk drives. There are various restoration methods according to the attribute (read-only (RO), read-and-writable (RW), etc.) of an S-VOL where an error has happened, including: a method of copying data of a RO S-VOL to the S-VOL where an error has happened; a method of replacing the S-VOL where an error has happened with a RO S-VOL; and a method of recovering a read-and-writable S-VOL by storing updates that have occurred in the RW S-VOL since a P-VOL and the RW S-VOL were separated in an increments-volume and replacing it with the RO S-VOL that has updated by data of the increments-volume. Furthermore, in the case of drive errors, a storage device where an error has happened is replaced, and the S-VOL is formed with another storage device normally operating. This enables the S-VOL to be recovered without changing the identification (for example, logical volume ID (LID)) thereof. Features and objects of the present invention other than the above will become clear by reading the description of the present specification with reference to the accompanying drawings.
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20040702
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20070508
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20050421
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98208.0
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VO, THANH DUC
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DATA I/O SYSTEM USING A PLURALITY OF MIRROR VOLUMES
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UNDISCOUNTED
| 1
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CONT-ACCEPTED
| 2,004
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10,884,699
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ACCEPTED
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Directory distributor
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Dividing a set of leaf objects having the same path of a directory namespace allows the divided path data sets to be distributed over separate physical stores (e.g., directory servers, network storage, separate memory, etc.). Distribution of divided path data sets over separate physical stores enhances scalability of a directory namespace and facilitates efficient utilization of resources. A directory distributor maintains information that indicates distribution of data path sets of a directory namespace and directs requests for the directory namespace to appropriate stores in accordance with this information.
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1. A method of processing directory requests for a distributed directory namespace, the method comprising: decoding at least part of a directory request to determine a value that corresponds to a distribution criteria, wherein sets of leaf objects having a same directory path in the directory namespace are distributed over separate stores in accordance with the distribution criteria; determining an appropriate one or more of the separate stores based at least in part on the value; and forwarding the directory request according to the determined appropriate one or more separate stores. 2. The method of claim 1 wherein determining the appropriate one or more separate stores is also based on the directory request's type. 3. The method of claim 2 wherein the appropriate one or more of the separate stores host a master copy of their corresponding leaf objects and the appropriate one or more of the separate stores host one or more replicates of the master copy. 4. The method of claim 1 further comprising broadcasting a second directory request to the separate stores if the second directory request does not indicate a second value that corresponds to the distribution criteria. 5. The method of claim 1 wherein the directory request includes one of a read type directory request and a write type directory request. 6. The method of claim 5 wherein the directory request is a writ type directory request, the method further comprising: receiving a read type directory request that corresponds to the write type directory request; and directing the directory request to the one of the separate stores that services the write type directory request. 7. The method of claim 1 wherein a requestor is authenticated to a first of the separate stores based on the requestor's identity that is represented in the first store, and authenticated to a second of the separate stores based on a generic identity mapped to the authenticated requestor's identity, wherein the generic identity is represented in the second store. 8. The method of claim 1 wherein the directory namespace is implemented as a directory information tree. 9. The method of claim 8 wherein the directory information tree is accessed in accordance with one or more standards including lightweight data access protocol and X.500. 10. The method of claim 1 wherein the distribution criteria includes one or more of attributes of the directory namespace and attributes of the leaf objects. 11. The method of claim 1 wherein determining the appropriate one or more of the separate stores includes hashing the value and looking up the appropriate one or more of the separate stores based at least in part on the hashed value. 12. The method of claim 1 wherein the directory namespace corresponds to one or more of electronic mail addresses, personnel information, phone numbers, assets, and security information. 13. The method of claim 1 embodied in a computer program product encoded on or more machine-readable media. 14. An application that directs directory requests to respective ones of separate stores that represent different sets of leaf objects of a directory namespace hierarchy, based at least in part on a distribution criteria, wherein the different sets of leaf objects have a same directory path in the directory namespace hierarchy and the different leaf objects of the directory namespace hierarchy are distributed among the separate stores according to the distribution criteria. 15. The application of claim 14 that broadcasts to the separate stores directory requests that do not indicate a value corresponding to the distribution criteria. 16. The application of claim 14 wherein the directory requests include read type directory requests and write type directory requests. 17. The application of claim 16 that directs read type directory requests to those respective ones of the separate stores representing replicated copies of the corresponding leaf objects. 18. The application of claim 16 that directs write type directory requests to those respective ones of the separate stores representing master copies of the corresponding leaf objects. 19. The application of claim 14 that tracks direction of write type directory requests and directs read type directory requests according to the tracking. 20. The application of claim 19 that maintains the tracking for the write type requests for their respective time periods corresponding to propagation delay for replication of write type requests. 21. The application of claim 19 that maintains the tracking for the write type requests until acknowledgement of replication completion of the respective write type requests. 22. The application of claim 14 wherein a requester is authenticated to a first of the separate stores based on the requestor's identity that is represented in the first store, and authenticated to a second of the separate stores based on a generic identity mapped to the authenticated requestor's identity, wherein the generic identity is represented in the second store. 23. The application of claim 14 wherein the directory namespace hierarchy is implemented as a directory information tree (DIT). 24. The application of claim 23 wherein the DIT is implemented in accordance with one or more standards that include X.500 and lightweight data access protocol. 25. The application of claim 14 wherein the separate stores includes one or more of separate memory, separate directory servers, and separate storage devices. 26. The application of claim 14 wherein the application includes a proxy application, a directory service application, and a network protocol application. 27. The application of claim 14 that broadcasts directory requests to the separate stores if the distribution criteria cannot be determined from the directory requests. 28. A method for servicing directory requests for a directory namespace, the method comprising: determining if a directory request indicates a value that corresponds to a distribution criteria of the directory namespace, wherein the directory namespace includes sets of leaf objects that are distributed among separate stores according to the distribution criteria, wherein the sets of leaf objects have a same directory path; and mapping the value to a first of the sets of leaf objects. 29. The method of claim 28 further comprising forwarding the directory request to a device that corresponds to the one of the sets of leaf objects. 30. The method of claim 29 wherein the device includes a directory server and a load balancer that load balances for a group of directory servers. 31. The method of claim 28 further comprising: forwarding the directory request to a first of the separate stores that hosts a master copy of the first set of leaf objects if the directory request is a write type directory request; and forwarding the directory request to a second of the separate stores that hosts a replicate of the master copy if the directory request is a read type directory request. 32. The method of claim 28 further comprising forwarding the directory request to network device that load balances read type directory requests to a group of the separate stores that host a replicate of a master copy of the first set of leaf objects if the directory request is a read type directory request. 33. The method of claim 28 further comprising forwarding the directory request to network device that load balances write type directory requests to a group of the separate stores that host a master copy of the first set of leaf objects if the directory request is a write type directory request. 34. The method of claim 28 further comprising: forwarding the directory request according to the mapping, wherein the directory request is a write type directory request; determining that a first of the separate stores services the forwarded directory request; and forwarding a second directory request to the destination if the second directory request is a read type directory request for the first set of leaf objects. 35. The method of claim 28 further comprising authenticating a requester to a first of the separate stores based on the requestor's identity that is represented in the first store, and authenticating to a second of the separate stores based on a generic identity mapped to the authenticated requestor's identity, wherein the generic identity is represented in the second store. 36. The method of claim 28 wherein the mapping includes hashing an attribute value of the directory request. 37. The method of claim 28 wherein the mapping comprises: hashing the attribute value; and looking up the first set of leaf objects with the hashed attribute value. 38. The method of claim 28 embodied in a computer program product encoded on one or more machine-readable media. 39. The method of claim 28 wherein the sets of leaf objects indicate information including one or more of E-mail addresses, security information, and phone numbers. 40. A method comprising: determining an appropriate one of a plurality of sets of leaf objects of a directory namespace for a directory request, the leaf objects of at least two of the plurality of sets of leaf objects having a same path in a directory namespace hierarchy, wherein each of the plurality of sets of leaf objects corresponds to a different one of a plurality of devices; and forwarding the directory request to a first of the plurality of devices that corresponds to the determined appropriate one of the plurality of sets of leaf objects. 41. The method of claim 40 wherein correspondence between individual ones of the plurality of sets of leaf objects and the different ones of the plurality of devices is based at least in part on a distribution criteria. 42. The method of claim 41 wherein the distribution criteria includes one or more of a leaf object attribute, a directory namespace attribute, and a user defined attribute. 43. The method of claim 40 wherein determining the appropriate one of the plurality of sets of leaf objects comprises hashing an attribute value of the directory request to generate an index value that corresponds to the appropriate set of leaf objects. 44. The method of claim 40 wherein the plurality of devices includes directory servers, network security devices, load balancers, storage devices, and memory devices. 45. The method of claim 40 wherein the first device corresponds to a master copy of the determined appropriate one of the plurality of leaf objects if the directory request is a write type directory request and to a replicate of the master copy if the directory request is a read type directory request. 46. The method of claim 40 wherein the directory namespace is implemented as a directory information tree. 47. The method of claim 46 wherein the directory information tree is implemented in accordance with one or more standards including lightweight data access protocol and X.500. 48. The method of claim 40 wherein the directory request is a write type directory request, the method further comprising forwarding read type directory requests for the determined appropriate one of the plurality of sets of leaf objects to the first device. 49. The method of claim 48 wherein the read type directory requests for the determined appropriate one of the plurality of sets of leaf objects are forwarded to the first device for a time period that relates to propagation delay. 50. The method of claim 48 wherein the read type directory requests for the determined appropriate one of the plurality of sets of leaf objects are forwarded to the first device until acknowledgement of replication completion. 51. The method of claim 40 wherein the determining the appropriate one of the plurality of sets of leaf objects is based at least in part on a distribution criteria value of the directory request that corresponds to a distribution criteria, which is at least part of the basis for distribution of the plurality of sets of leaf objects. 52. The method of claim 51 further comprising: receiving a second directory request; and broadcasting the second directory request if a distribution criteria of the second directory request cannot be determined. 53. The method of claim 40 embodied in a computer program product encoded on one or more machine-readable media. 54. An apparatus comprising: a set of one or more processors; and a means for associating directory requests with corresponding ones of a plurality of separately stored sets of leaf objects, at least two sets of the plurality of sets of leaf objects having a same path in a directory namespace. 55. The apparatus of claim 54 wherein the plurality of sets of leaf objects is stored separately in accordance with a distribution criteria. 56. The apparatus of claim 55 further comprising means for broadcasting those directory requests that do not indicate the distribution criteria. 57. The apparatus of claim 54 further comprising means to forward write type directory requests to devices that correspond to master copies of associated sets of leaf objects and read type directory requests to devices that correspond to replicates of the master copies. 58. The apparatus of claim 54 further comprising means to map a requestor's authenticated identity to a generic identity, wherein the requestor's identity is authenticated to a first device and the generic identity is represented in a second device that does not represent the requestor's identity. 59. A computer program product encoded on one or more machine-readable media, the computer program product comprising: a first sequence of instructions to receive a directory request for a directory namespace; and a second sequence of instructions to direct the directory request to one of a plurality of separate stores, based at least in part on a value that corresponds to a distribution criteria, wherein the directory namespace includes a plurality of leaf objects, which have a same directory path in the directory namespace, distributed over the plurality of separate stores. 60. The computer program product of claim 59 comprising the second sequence of instructions to broadcast to the separate stores directory requests that do not indicate a distribution criteria value. 61. The computer program product of claim 59 comprising the second sequence of instructions to distinguish read type directory requests and write type directory requests, and forward the write type directory requests to those of the separate stores that host master copies of their corresponding ones of the plurality of leaf objects and the read type directory requests to those of the separate stores that host replicates of the master copies.
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BACKGROUND 1. Field of the Invention The present invention relates to the field of information processing systems. More specifically, the present invention relates to distributed directory information. 2. Description of the Related Art Information directories are organized repositories of typically descriptive, attribute based information. An information directory may be an E-mail address directory, a telephone directory, a network directory, a public key directory, a company directory, etc. The International Standards Organization (ISO) and International Telecommunications Union (ITU) provided X.500 as a standard for organizing information directories and for directory services. The complexity of the X.500 standard deters many organizations from implementing the entire standard. In response to the comprehensiveness of X.500, the lightweight data access protocol (LDAP) was developed. LDAP is a set of protocols for accessing information directories. LDAP is based on some sections of X.500. In contrast to the X.500 standard that supports systems that conform to layer 7 of the OSI network reference model, LDAP supports systems that conform to layer 3/4 of the OSI network reference model. Universal Description, Discovery, and Integration (UDDI) is another directory related protocol. UDDI is a service discovery protocol for Web services. LDAP and similar standards define a hierarchical directory information tree with different levels for each category of information. A directory information tree has a root node, which contains information about the host directory server. The root node references containers or subdirectories. A container or subdirectory may include additional containers, or may include objects (also referred to as entries, leafs, etc.), which is a basic storage element of the directory information tree. A unique identifier (UID) names each object of an information directory tree. An object's distinguished name (DN) identifies the path from the root to the object and the unique identifier for the object. For example, assume a company maintains a directory information tree. The root node of the DIT indicates information about the directory server that hosts the DIT and the name of the company. The root node references two containers: 1) employees; and 2) customers. The employee container includes objects that indicate names, telephone numbers, and addresses of employees of the company. Likewise, the customer container includes objects that indicate the same information for customers of the company. The UID for each person, whether employee or customer, is their name. The DN for each customer would be the path to the customer object, which would include the company name (root node), the customer container, and the UID for the relevant customer. Users that access DITs make read type requests and write type requests. Write type requests include create operations, update operations, etc. Read type requests include search operations, compare operations, etc. Organizations typically allow anonymous users to have read type access to their DITs. Organizations typically do not allow such liberal access for writing to their DITs. In addition, certain branches of a DIT may be restricted from categories of users, especially anonymous users. To access restricted information or to perform restricted operations, a user is authenticated to the directory server that hosts the target information. Typically a directory server hosts security credentials of those users authorized to access the information on the directory server. Some DITs represent a massive amount of information. Storing all of the information for one of these large DITs overwhelms typical network resources. If a DIT includes hundreds of thousands of entries and is repeatedly accessed, performance of the host directory server suffers. In addition, throughput of the network conduit to the directory server is significantly impacted. Instead of storing an entire DIT on a single directory server, a DIT can be partitioned. A DIT is partitioned according to the organization of the DIT. Using the previous example, an employee directory server hosts all of the employee objects and a customer directory server hosts all of the customer objects. Unfortunately, DIT partitioning is confined by the organization of containers and does not address significant throughput and performance issues. Using the previous example, if there are a million customers and five hundred thousand employees for the company, partitioning the DIT still places a million objects on the customer directory server and half of a million objects on the employee directory server. SUMMARY Dividing a set of leaf objects having the same path of a directory namespace allows the divided path data sets to be distributed over separate physical stores. Distribution of divided path data sets over separate physical stores enhances scalability of a directory namespace and facilitates efficient utilization of resources. Leaf objects of a directory namespace are distributed in accordance with a given one or more distribution criteria. A representation of the distribution of leaf objects is utilizes to properly direct directory requests. According to some embodiments of the invention, an application directs directory requests to respective ones of separate stores that represent different sets of leaf objects of a directory namespace hierarchy, based at least in part on a distribution criteria. The different sets of leaf objects have a same directory path in the directory namespace hierarchy and the different leaf objects of the directory namespace hierarchy are distributed among the separate stores according to the distribution criteria. According to some embodiments of the invention, a method of processing directory requests for a distributed directory namespace comprises decoding at least part of a directory request to determine a value that corresponds to a distribution criteria. Sets of leaf objects having a same directory path in the directory namespace are distributed over separate stores in accordance with the distribution criteria. The method also comprises determining an appropriate one or more of the separate stores based at least in part on the value, and forwarding the directory request according to the determined appropriate one or more separate stores. According to some embodiments of the invention, a method for servicing directory requests for a directory namespace comprises determining if a directory request indicates a value that corresponds to a distribution criteria of the directory namespace. The directory namespace includes sets of leaf objects that are distributed among separate stores according to the distribution criteria. The sets of leaf objects have a same directory path. The method also comprises mapping the value to a first of the sets of leaf objects. According to some embodiments of the invention, a method comprises determining an appropriate one of a plurality of sets of leaf objects of a directory namespace for a directory request, the leaf objects of at least two of the plurality of sets of leaf objects having a same path in a directory namespace hierarchy. Each of the plurality of sets of leaf objects corresponds to a different one of a plurality of devices. The method also comprises forwarding the directory request to a first of the plurality of devices that corresponds to the determined appropriate one of the plurality of sets of leaf objects. According to some embodiments of the invention, an apparatus comprises a set of one or more processors, and a means for associating directory requests with corresponding ones of a plurality of separately stored sets of leaf objects. At least two sets of the plurality of sets of leaf objects have a same path in a directory namespace. According to some embodiments of the invention, a computer program product encoded on one or more machine-readable media comprises a first sequence of instructions to receive a directory request for a directory namespace, and a second sequence of instructions to direct the directory request to one of a plurality of separate stores, based at least in part on a value that corresponds to a distribution criteria. The directory namespace includes a plurality of leaf objects, which have a same directory path in the directory namespace, distributed over the plurality of separate stores. These and other aspects of the described invention will be better described with reference to the Description of the Preferred Embodiment(s) and accompanying Figures. BRIEF DESCRIPTION OF THE DRAWINGS The present invention may be better understood, and its numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings. FIG. 1 is a conceptual diagram illustrating an exemplary directory distributor module according to one realization of the invention. FIG. 2 is a graphical diagram that illustrates a distributed data set of a directory namespace hierarchy according to one realization of the invention. FIG. 3 is an exemplary flowchart for routing a request to the appropriate data set data owner according to some realizations of the invention. FIG. 4 depicts a directory distributor performing type based routing of requests to data complexes according to some realizations of the invention. FIG. 5 is a flowchart that depicts type based directory request routing according to some realizations of the invention. FIGS. 6A-6B depict exemplary data structures for type based directory request routing according to some realizations of the invention. FIG. 6A depicts an exemplary implementation of a data distribution table according to some realizations of the invention. FIG. 6B depicts an exemplary implementation of a single look up data distribution table according to some realizations of the invention. FIG. 7 depicts a flowchart for processing a validating read request according to some realizations of the invention. FIG. 8 depicts an exemplary directory request affinity table according to some realizations of the invention. FIG. 9 is a flowchart that depicts maintenance of a directory request affinity table according to some realizations of the invention. FIGS. 10A-10B depict direction of validating read requests according to some realizations of the invention. FIG. 10A depicts update of a directory request affinity table with incoming write requests according to some realizations of the invention. FIG. 10B depicts processing read requests subsequent to write requests according to some realizations of the invention. FIG. 11 depicts a directory distributor controlling access to data owners hosting a directory namespace according to some realizations of the invention. FIG. 12 depicts a flowchart for determining support of generic user account mapping according to some realizations of the invention. FIGS. 13A-13B depict organization of security information according to some realizations of the invention. FIG. 13A depicts exemplary security information leaf objects according to some realizations of the invention. FIG. 13B depicts user-based organization of security information according to some realizations of the invention. FIG. 14 depicts a flowchart for controlling access based on generic account mapping and requested operation according to some realizations of the invention. FIG. 15 depicts an exemplary system according to some realizations of the invention. The use of the same reference symbols in different drawings indicates similar or identical items. DESCRIPTION OF THE PREFERRED EMBODIMENT(S) The description that follows includes exemplary systems, methods, techniques, instruction sequences and computer program products that embody techniques of the present invention. In particular, in some instances particular implementations suited to transactions, protocols, and services typical of servers such as those in accordance with Lightweight Data Access Protocol (LDAP), Universal Description, Discovery and Integration (UDDI), or the like, are described in some detail. However, it is understood that the described invention may be practiced without these specific details. In other instances, well-known protocols, structures and techniques have not been shown in detail in order not to obscure the invention. Overview Dividing a set of leaf objects having the same path of a directory namespace allows the divided path data sets to be distributed over separate physical stores (e.g., directory servers, network storage, separate memory, etc.). Distribution of divided path data sets over separate physical stores enhances scalability of a directory namespace and facilitates efficient utilization of resources. A directory distributor maintains information that indicates distribution of data path sets of a directory namespace and directs requests for the directory namespace to appropriate stores in accordance with this information. Directing requests from the directory distributor to the separate stores based on the type of request also increases efficient utilization of resources. The directory distributor tracks write requests for validating read requests, and directs validating read requests to the store that services the write request, thus reducing network traffic and providing reliable data. Since leaf objects are distributed over separate physical stores, a requestor's information may be hosted on a store that is separate from the store that hosts the leaf object of interest to the requestor. Creating a generic user account and mapping an authorized requestor to the generic user account, allows an authorized requester to access data over separate stores. Distributing Divided Path Data Sets over Separate Physical Stores FIG. 1 is a conceptual diagram illustrating an exemplary directory distributor module according to one realization of the invention. In FIG. 1, a server 103 hosts a distributor module 104. The server 103 and the distributor module 104 process requests for a directory backend 123. The directory backend includes data owners 105, 107, 109, and 111, respectively referred to as Alpha, Beta, Delta, and Gamma. The data owners Alpha 105, Beta 107, Delta 109, and Gamma 111 respectively host a divided path data set 113, a divided path data set 115, an undivided path data set 117, and an undivided path data set 119. FIG. 2 is a graphical diagram that illustrates a distributed data set of a directory namespace hierarchy according to one realization of the invention. A directory namespace hierarchy 201 has a root node COMPANY. The directory namespace hierarchy illustrated in FIG. 2 is implemented as a directory information tree, but various realizations of the invention implement the directory namespace according to different data structures. At the next level of the directory namespace hierarchy 201 are nodes PEOPLE and ASSETS. Below the node PEOPLE are nodes CUSTOMERS, ASSOCIATES, and SECURITY. The CUSTOMERS node includes leaf objects that are split into the divided path data set 113 and the divided path data set 115. If the unique identifier for these objects were last names, then in one example, the leaf objects are distributed based on last names (i.e., the last name is a distribution criteria). In this example, the divided path data set 113 includes all leaf objects identified with last names that begin with a letter from A-G, and the divided path data set 115 includes all leaf objects identified with last names that begin with a letter from H-Z. All of the leaf objects in the divided path data sets 113 and 115 have the same path names in the directory namespace hierarchy 201. The path for all leaf objects in the divided path data set 113 includes nodes COMPANY, PEOPLE, and CUSTOMERS. The path of the leaf objects in the divided path data set 115 includes the same nodes. Hence, leaf objects of multiple divided path data sets have the same path in a directory namespace hierarchy. Conversely, leaf objects of different undivided path data sets do not have the same data path, which is the conventional grouping of data sets. The undivided path data set 117 includes all of the leaf objects under the nodes SECURITY and ASSOCIATES. The undivided path data set 119 includes all of the leaf objects in a subtree 203 that is below the node ASSETS. A directory namespace is divided for a range of reasons that include customer preferences, data layout, etc. For example, an administrator or designer may decide to divide the leaf objects having the path COMPANY->PEOPLE->CUSTOMERS because these leaf objects account for the largest percentage of leaf objects in the directory namespace hierarchy 201. Alternatively, or in addition, an administrator or designer may divides the nodes in the directory namespace hierarchy 201 for various reasons related to hardware resources, network resources, etc. Referring to FIG. 1, the server 103 receives requests 101A-101F. The distributor module 104 processes the requests 101A-101F and accesses a data distribution table 121. The data distribution table 121 indicates location of data. In FIG. 1, the data distribution table 121 includes a first column of mapping values for associating or mapping attribute values of requests with a particular data set. The attribute values correspond to the distribution criteria for the directory namespace hierarchy. The data distribution table 121 includes a mapping value for each data set in the backend. Various techniques can be implemented to associate a request with a particular data set. For example, the mapping values can include one or more of hash values, individual characters, numbers, indices, etc. For example, if the data sets are distributed according to last names as in FIG. 2, the mapping values may be hashes of the first three letters of last names represented in each data set, a range of characters for last names represented in each data set, a single character, an integer that corresponds to a character, etc. In addition, distribution of a directory namespace hierarchy may be based on multiple distribution criteria and the mapping values would be one or more values corresponding to the combination of distribution criteria. The data distribution table 121 also includes a second column of values indicating associated data owners of data sets. These data owner values may be network addresses, alphanumeric strings, references to network data structures, etc. The data distribution table 121 may also include additional information for transmitting the request, information for modifying the request, or possibly other information. The distributor module 104 maps the requests 101A-101F to the appropriate data set in the data distribution table 121 with a mapping value and ascertains the data owner for the appropriate data set. FIG. 3 is an exemplary flowchart for routing a request to the appropriate data set data owner according to some realizations of the invention. At block 301, a request is received. At block 302, at least a part of the request is decoded to determine one or more distribution attributes (i.e., one or more attribute values that correspond to the directory namespace hierarchy distribution criteria). At block 303, it is determined if the request includes the distribution attribute. If the request includes the distribution attribute, then control flows to block 313. If the request does not include the distribution attribute, then control flows to block 305. At block 305, the request is broadcast to the owners of all relevant data sets. For example, if it can be determined that the request corresponds to customers of the directory namespace hierarchy illustrated in FIG. 2, but the request does not include a last name, then the request is broadcast to all data owners of data sets of leaf objects under the node customers and not transmitted to data owners of other data sets. It may not be possible to determine relevant data sets, so the request is broadcast to all data owners. From block 305, control flows to block 317. At block 313, the data owner of the relevant data set that corresponds to the distribution attribute is looked up. For example, logic, implemented as hardware, software, or a combination of hardware and software, maps the distribution attribute of the request to one of the entries in the data distribution table 121. At block 315, the request is transmitted to the data owner. At block 317, the result(s) are provided to the requestor when received from the data owner. Dividing path data sets of a directory namespace hierarchy allow flexible implementation of a directory namespace hierarchy and facilitate optimal utilization of hardware and network resources for hosting and accessing the directory namespace hierarchy. A directory distributor, ranging from dedicated hardware to hosted software, routes requests of a directory namespace to appropriate data owners of data sets. Directing Directory Requests Based on Request Type FIG. 4 depicts a directory distributor performing type based routing of requests to data complexes according to some realizations of the invention. A server 403 hosts a distributor module 404 and receives requests 401A-401F. The distributor module 404 accesses a data distribution table 406 to direct the requests 401A-401F to the appropriate data complexes. A data complex Alpha 433 includes a supplier data owner 405, and consumer data owners 409A-409F. The supplier data owner 405 hosts a divided path data set master copy 410. The consumer data owners 409A-409F respectively host divided path data set replicates 417A-417F. A data complex Beta 435 includes a supplier data owner 407 and consumer data owners 411A-411F. The supplier data owner 407 hosts a divided path data set master copy 413. The consumer data owners 411A-411F respectively host divided path data set replicates 419A-419F. The distributor module 404 directs write type directory requests to the supplier data owners 405 and 407. The distributor module 404 directs read type directory requests to load balancers 451 and 453. Although FIG. 4 illustrates load balancers 451 and 453 for load balancing traffic respectively to the consumers of the data complexes 433 and 435, various implementations of the invention transmit requests to consumers of data complexes differently (e.g., utilizing hardware load balancers, software load balancers in the distributor server, incorporating load balancing techniques into the distributor module 404, etc.). The supplier data owner 405 handles write type requests relevant to the hosted divided path data set master 410. Likewise, the supplier data owner 407 handles write type requests relevant to the hosted divided path data set master 413. The consumer data owners 409A-409F service read type requests relevant to the divided path data set of data complex 433 with replicate copies of the divided path data set. The consumer data owners 411A-411F service read type requests relevant to the divided path data set of data complex 435 with replicate copies of the divided path data set. These consumer data owners service requests in parallel for their respective data complexes, thus handling a larger number of requests than a single consumer data owner without impacting time to service the request. Moreover, additional consumer data owners can be added to data complexes for hosting more replicates relatively easily in order to satisfy demand. With respect to the suppliers, resources of the suppliers 405 and 407 can be dedicated to servicing write type requests since resources are not consumed servicing read type requests. Directing requests based at least in part on the request type allows for efficient utilization of resources, scalability, and the capability to service requests of a directory namespace having a vast number of leaf objects. FIG. 5 is a flowchart that depicts type based directory request routing according to some realizations of the invention. At block 501, a request is received. At block 503, at least part of the request is decoded to determine a distribution attribute. At block 505, it is determined if the requests includes the distribution attribute. If the request does not include the distribution attribute, then control flows to block 507. If the request includes the distribution attribute, then control flows to block 521. At block 507, data complexes of relevant data sets are selected. At block 509, the type of the request is determined. If the request is a read type request, then control flows to block 515. If the request is a write type request, then control flows to block 513. At block 513, the write request is broadcast to suppliers of the selected data complexes. At block 515, consumers of the selected data complexes are selected according to a load balancing algorithm. At block 517, the read request is broadcast to the selected consumers. In alternative realizations of the invention, the read request is broadcast to the selected data complexes and the read request is transmitted to a particular consumer of each data complex according to a load balancing mechanism at the front end of each data complex. It should be appreciated that a variety of techniques can be utilized for delivering requests to particular data owners in a variety of architectures (e.g., single consumer and single supplier model does not include load balancing, a single supplier multiple consumer model includes load balancer at the front end of the data complex or within the data distributor, and multiple supplier multiple consumer model includes load balancing at the data distributor, at the front end of each data complex, at both the front end of each data complex and within the data distributor, etc.). Control flows from block 517 to block 519. At block 521, the data complex of the corresponding data set is looked up in accordance with the distribution attribute. At block 523, the request type is determined. If the request is a read request, then control flows to block 529. If the request is a write type request, then control flows to block 525. At block 529, the consumer in the selected data complex is selected according to the load balancing algorithm. At block 531, the read request is transmitted to the selected consumer. At block 519, the received result(s) is provided to the requestor. At block 525, the write request is transmitted to the supplier of the selected data complex. FIGS. 6A-6B depict exemplary data structures for type based directory request routing according to some realizations of the invention. FIG. 6A depicts an exemplary implementation of a data distribution table according to some realizations of the invention. A data distribution table 600 includes a data distribution index data structure 601, a data complex data structure 603, and a data complex data structure 605. The data distribution index data structure 601 includes a first column of indices that correspond to particular data sets. The data distribution index data structure 601 also includes a second column, which indicates data complexes. In FIG. 6A, the first entry of the data distribution index data structure 601 indicates an index for a divided path data set 113. The index for the divided path data set 113 is associated with or mapped to a data complex Alpha in the first entry. In the second entry, an index for the divided path data set 115 is associated with a data complex Beta. The second column of the first entry references the data complex data structure 605. The data complex data structure 605 includes two columns. The first column of the data complex data structure 605 indicates members of the data complex described by the data complex data structure 605. Entries in the first column of the data complex data structure 605 indicate members Alpha, Alpha-2, and Alpha-N. The second column of the data complex data structure 605 indicates whether the corresponding data complex member is a supplier or a consumer. According to the data complex data structure 605, Alpha is a supplier, while members Alpha-2 and Alpha-N are consumers. The second column of the second entry of the data distribution index data structure 601 references the data complex data structure 603. The data complex data structure 603 describes the data complex Beta. As with the data complex data structure 605, the data complex data structure 603 includes two columns: a first column indicating members of the Beta data complex; and a second column indicating whether a member of the Beta data complex is a consumer or a supplier. When a request is processed, the first column of the data distribution index data structure 601 is searched for an index value that corresponds to the distribution attribute of the request. Assuming the distribution attribute of the request maps to data complex Alpha, the data complex data structure 605 is searched based on the type of request. If the request is a write type request, then the data complex data structure 605 is searched for a supplier entry. The data complex data structure 605 indicates one supplier entry, which becomes the destination for the write request. If the request is a read type request, then the data complex data structure 605 is searched for a consumer entry. The data complex data structure 605 indicates multiple consumer entries. Various techniques can be employed for selecting one of the consumers as the destination for the read request (e.g., the data complex data structure includes a flag to identify which of the consumers should be selected for a particular read request, all of the consumers are input into a load balancing mechanism that selects one of the consumers, the reference to the list of consumers is modified at given times in accordance with a load balancing mechanism, the reference points to a first consumer in the data complex data structure and the list is reordered in accordance with a load balancing algorithm, etc.). These various techniques can also be applied for selecting a supplier if a data complex includes multiple suppliers. FIG. 6B depicts an exemplary implementation of a single look up data distribution table according to some realizations of the invention. A data distribution table 602 includes a data distribution index data structure 607 and data owner data structures 609A-609D. Each entry of the data distribution index data structure 607 includes an index field, a supplier reference field, and a consumer reference field. The first and second entries of the data distribution index data structure 607 respectively indicate an index for divided path data set 113 and an index for divided path data set 115. The suppliers field of the first entry references the data owner data structure 609A, which indicates a supplier for a data complex Alpha. The consumers field of the first entry references the data owner data structure 609B, which indicates a load balancer for the consumers of the data complex Alpha. The suppliers field of the second entry references the data owner data structure 609C, which indicates a supplier for a data complex Beta. The consumers field of the second entry references the data owner data structure 609D, which indicates a load balancer for the consumers of the data complex Beta. When a request is processed, the data distribution index data structure 607 is searched for an entry that corresponds to the request being processed. Once a corresponding entry is located, the suppliers field is followed if the request is a write type request and the consumers field is followed if the request is a read type request. Realizations of the invention utilize any of a number of data structures or combinations of data structures (e.g., hash tables, binary search trees, tries, arrays, etc.) to maintain information for directing requests. Furthermore, realizations of the invention implement data structures in hardware according to any one or more of different techniques (e.g., content addressable memory, random access memory, a combination of CAM and RAM, hardware lookup tables, etc.). Directory Request Affinity Although directing read requests and write requests to different data owners allows for efficient service of requests, improved resource utilization, and architecture flexibility, directing certain sequences of requests differently facilitates servicing requests without stale data. In particular, read requests are sometimes submitted to validate write requests. At times, the latency to propagate changes to a directory namespace over separate stores is greater than the time to receive and service validating read requests. For example, a user submits a write request soon followed by a validating read request, but the read request and the write request are directed to different data owners. If the read request is serviced before the change to the directory namespace from the write request is replicated to the data owner servicing the read request, then the user is provided a result that is based on stale data. Tracking write requests allows validating read requests to be directed to the appropriate data owner. FIG. 7 depicts a flowchart for processing a validating read request according to some realizations of the invention. At block 701, a request is received. At block 703, at least part of the received request is decoded to determine a distribution attribute. At block 705, it is determined if the request includes the distribution attribute. If the request does not include the distribution attribute, then control flows to block 707. If the request includes the distribution attribute, then control flows to block 721. At block 707, data complexes of data sets that are relevant to the received request are selected. At block 709, the request type is determined. If the request is a write request, then control flows to block 711. If the request is a read request, then control flows to block 745 of FIG. 7B. At block 711, the received request is broadcast to suppliers of the selected data complexes. At block 715, an affinity table is updated upon receiving acknowledgment for the write request. The affinity table tracks write requests and the suppliers that service the write requests. An example affinity table is illustrated in FIG. 8. At block 721, the data complex of the corresponding data set is looked up in accordance with the distribution attribute. At block 723, the request type is determined. If the request is a write request, the control flows to block 725. If the request is a read request, then control flows to block 731 of FIG. 7B. At block 725, the received request is transmitted to the supplier of the data complex. Control flows from block 725 to block 715. FIG. 7B depicts a flowchart continuing from FIG. 7A for processing validating read requests according to some realizations of the invention. At block 745, it is determined if the affinity table indicates a write request entry that is relevant to the received request. If the affinity table does not indicate such a write request, then control flows to block 747. If the affinity table indicates such a write request, then control flows block 735. At block 747, the consumers of selected data complexes are selected according to a load balance algorithm. At block 749, the request is broadcast to the selected consumers. At block 739, the result(s) are provided to the requestor when received. At block 731, it is determined if the affinity table indicates a write request entry that is relevant to the received request. If the affinity table does not indicate such a write request, then control flows to block 741. If the affinity table indicates such a write request, then control flows to block 735. At block 741, a consumer in the data complex is selected according to the load balance algorithm. At block 743, the request is transmitted to the selected consumer. Control flows from block 743 to block 739. FIG. 8 depicts an exemplary directory request affinity table according to some realizations of the invention. A variety of techniques are available for implementing the directory request affinity table, but FIG. 8 illustrates an example of an implementation of a data request affinity table to aid in understanding the described invention. Each entry of a directory request affinity table 800 includes a leaf object field, a writing supplier field, a write ACK received field, and a timestamp field. Various realizations of the invention may include additional or fewer fields than those illustrate in FIG. 8. The leaf object field of each entry in the directory request affinity table 800 indicates a particular leaf object (e.g., UID, distinguished name, etc.) within a directory namespace hierarchy. The writing supplier field of each entry indicates the data owner that is responsible for servicing the write requests corresponding to the indicated leaf object. The write ACK received field indicates whether or not acknowledgment has been received for a particular write request. The write ACK received field can be utilized in various manners (e.g., indicating that a write request has been serviced, indicating that replication of data modified by the write request has been started or completed, etc.). The timestamp field indicates the time when the write request was transmitted. The timestamp field can be utilized for garbage collection or expiration type operations. For example, after a given amount of time has passed since the write request was serviced, the entry in the directory request affinity table is cleared. Various realizations of the invention clear entries in a directory request affinity table differently (e.g., after expiration of a predefined limit related to propagation delay, after expiration of a dynamically adjusted limit related to propagation delay, after verification of replication, etc.). FIG. 9 is a flowchart that depicts maintenance of a directory request affinity table according to some realizations of the invention. At block 901, a write request is received. At block 903, an entry is created in the affinity table. The block 905, the supplier that performs the write request is determined. The supplier may be determined before transmission of the write request, after transmission of the write request, after receiving acknowledgment from a supplier, etc. If the writing supplier cannot be determined yet, then control flows to block 909. If the writing supplier can be determined, then control flows to block 907. At block 907, the writing supplier is indicated in the affinity table entry. The control flows from block 907 to block 909. At block 909, completion of the write request is indicated in the affinity table entry after receiving a write acknowledgment. At block 911, the entry is cleared in response to receiving acknowledgment that the written entry has been replicated. In some realizations of the invention, the entry is not cleared until a later point in time and instead an element of the entry is set to indicate whether the entry should be cleared, skipped, etc. FIGS. 10A-10B depict direction of validating read requests according to some realizations of the invention. FIG. 10A depicts update of a directory request affinity table with incoming write requests according to some realizations of the invention. Clients 1001 and 1003 are coupled with a server 1005 via a network 1006. The client 1001 submits to the server 1005 a write request 1053 for a leaf object B and a write request 1051 for a leaf object A. The client 1003 submits to the server 1005 a write request 1055 for a leaf object C. The server 1005 hosts a data distributor module 1007, which accesses the directory request affinity table 1009. The distributor module 1007 directs requests to data complexes Alpha 1041 and Beta 1043. The data complex Alpha 1041 includes a supplier 1011, a supplier 1015, and consumers 1017A-1017G. The data complex data 1043 includes a supplier 1013, a supplier 1021, and consumers 1023A-1023G. The data distributor module 1007 updates the directory request affinity table 1009 to reflect processing of the write requests 1051, 1053, and 1055. Various realizations of the invention indicate the leaf objects differently (e.g., hash of the UID of the leaf object, an alphanumeric string representation of the leaf object's UID, a hash of the leaf object's DN, a hash of the leaf object's DN, a representation of the UID and the path, a system identifier associated with the leaf object, a combination of the session identifier and the UID, a requestor identifier, a combination of the requester identifier, the session identifier and the UID, etc.). The write request 1055 is transmitted to the supplier 1011 of the Alpha data complex. The write request 1051 is transmitted to the supplier 1015 of the Alpha data complex. The write request 1053 is transmitted to the supplier 1013 of the Beta data complex. FIG. 10B depicts processing read requests subsequent to write requests according to some realizations of the invention. In FIG. 10B, The client 1001 submits a read request 1063 for the leaf object B and a read request 1061 for the leaf object A. The client 1003 submits a read request 1065 for leaf object C. The data distributor module 1007 consults the directory request affinity table 1009. The directory request affinity table 1009 indicates that Beta-1, which is the supplier 1013, hosts data relevant to a validating read for leaf object B, and that data owner Alpha-1, which is the supplier 1015, hosts data relevant to a validating read for leaf object C. The directory request affinity table 1009 does not include an entry that indicates leaf object A. The data distributor module 1007 consults its data distribution table 1031 to determine where to direct the read request 1061. The data distribution table 1031 indicates that the Alpha data complex 1041 hosts data relevant to the read request 1061. The validating read requests 1063 and 1065 are respectively transmitted to the supplier 1013 and the supplier 1011 in accordance with the directory request affinity table 1009. However, the validating read request 1061 is transmitted to a load balancer 1029 for the Alpha data complex 1041 in accordance with the data distribution table 1031. The users of the clients 1001 and 1003 will be able to validate their write requests because the responses to their read requests are based on up-to-date data. Besides providing reliable data, tracking write requests and their writing suppliers reduces network traffic resulting from repeated transmission of validating read requests during propagation delay. In addition, users typically end their session upon receiving a response that validates their write request, thus resources used for sessions are freed. Mapping Generic User Accounts Just as a read request and a write request for the same leaf object may be serviced by different data owners, a requestor's account information and the requested data may be stored on separate data owners. Creating generic user accounts on each separate store and mapping authorized requesters to these separate stores avoids performance of redundant authorization operations and provides access flexibility. FIG. 11 depicts a directory distributor controlling access to data owners hosting a directory namespace according to some realizations of the invention. A client 1101 transmits a user ID to a directory distributor 1103. The directory distributor 1103 determines which data owner hosts the account corresponding to the user ID. The directory distributor 1103 forwards the user ID to the determined data owner. A data owner 1105 receives the user ID and retrieves the relevant account information, which includes security information. The data owner 1105 authenticates the user. After authenticating the user, the data owner 10S provides security credentials for the user. The data owner 1105 transmits these security credentials to the directory distributor 1103. The directory distributor forwards the security credentials to the client 1101. The client 1101 transmits a session request to the directory distributor 1103. The directory distributor 1103 opens a session with the requesting client 1101 and provides session information (e.g., connection handle) to the requesting client 1101. The client 1101 transmits a directory request to the directory distributor 1103 with the provided session information. The directory distributor 1103 processes the request and, if relevant, maps the requester to a generic identity. FIG. 12 depicts a flowchart for applying generic user account information according to some realizations of the invention. At block 1201, a request is received from an authenticated requester. At block 1203, the relevant data owner for the request is determined. At block 1205, it is determined if the relevant data owner is the authenticating data owner. If the data owners are the same, then control flows to block 1207. If the data owners are not the same, then control flows to block 1211. At block 1207, the request is forwarded to the data owner. At block 1211, it is determined if the authenticated requestor maps to a generic user. For example, an entry for the requestor includes a distinguished name that indicates a generic identity, the class of service for the requestor indicates the generic identity, etc. If the authenticated requester does not map to a generic user, then control flows to block 1213. If the authenticated requester maps to the generic user, then control flows to block 1215. At block 1213, access is denied. At block 1215, the generic user is indicated in the request. For example, in a proxied authorization control field, the generic user identity is indicated. In addition to authenticated users, realizations of the invention provide generic user identities to unauthenticated requesters. For example, users are permitted to access to a directory for read only purposes without authentication. Furthermore, realizations of the invention provide for default mappings of authenticated requestors to a first set of one or more generic identities and default mappings of unauthenticated requestors to a second set of one or more generic identities. FIGS. 13A-13B depict organization of security information according to some realizations of the invention. FIG. 13A depicts exemplary security information leaf objects according to some realizations of the invention. In FIG. 13A, a directory namespace hierarchy includes a node SECURITY CREDENTIALS. The node SECURITY CREDENTIALS includes a number of leaf objects. A first leaf object is illustrated as having an attribute CN=Generic A. The first leaf object is illustrated as also having an attribute Access Level=Admin. A second leaf object contained in the node SECURITY CREDENTIALS is illustrated as having an attribute CN=Generic B and an attribute Access Level=Reader. Various realizations of the invention map authenticated users to generic accounts with different techniques. For example, an authenticated user may map to generic B based on a match between access levels (i.e., the authenticated user has a read access level which is the same as generic B's access level). FIG. 13B depicts user-based organization of security information according to some realizations of the invention. In FIG. 13B, the following four nodes exist at the same level in a directory namespace hierarchy: READ LEVEL USERS, WRITE LEVEL USERS, ADMINS, AND GENERIC USERS. Each of these nodes contain leaf objects with security information for user accounts. A variety of techniques can be utilized for adding generic user accounts to directory namespace. The generic account may be grouped separately, grouped into access level nodes, etc. Creating a set of one or more generic user accounts in each of the separate data owners allows flexible requestor access and management of security information. For example, all of the security credentials for an organization may be stored on a single security directory server or distributed over multiple security directory servers, and all requesters of data on non-security directory servers will be mapped to generic accounts on the non-security directory servers hosting data of the directory namespace. User authorization also includes request type based restriction of access. FIG. 14 depicts a flowchart for controlling access based on generic account mapping and requested operation according to some realizations of the invention. At block 1401, the data owner receives a request from a directory distributor. At block 1403, it is determined if the user has been authenticated for the receiving data owner. If the user is not authenticated for the receiving data owner, then control flows to block 1405. If the user has been authenticated for the receiving data owner, then control flows to block 1413. At block 1405, it is determined if the requested operation is allowed for the authenticated requester. If the requested operation is not allowed, then control flows to block 1407. If the requested operation is allowed, then control flows to block 1409. At block 1413, it is determined if generic users are allowed. If generic users are allowed, then control flows to block 1417. If generic users are not allowed, then control flows to block 1415. At block 1415, access is denied. At block 1417, generic user identity is determined from the request. For example, the data owner or backend set processes the request as if requested by the generic identity indicated in the control in accordance with the proxied authorization control field of the request instead of processing the request as if received from the authenticated requester. At block 1419, the requestor is allowed access in accordance with the generic identity's privileges. While the flow diagrams show a particular order of operations performed by certain realizations of the invention, it should be understood that such order is exemplary (e.g., alternative realizations may perform the operations in a different order, combine certain operations, overlap certain operations, perform certain operations in parallel, etc.). For example, additional operations may be performed to load balance a request over multiple suppliers in a data complex. For example, in FIG. 12, the load balancer may indicate the generic identity by default and set a flag if the relevant data owner is not the authenticating data owner. With respect to FIG. 14, block 1413 may not be performed. Instead, the control may flow from block 1417 to block 1405. The described invention may be provided as a computer program product, or software, that may include a machine-readable medium having stored thereon instructions, which may be used to program a computer system (or other electronic devices) to perform a process according to the present invention. A machine readable medium includes any mechanism for storing or transmitting information in a form (e.g., software, processing application) readable by a machine (e.g., a computer). The machine-readable medium may include, but is not limited to, magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto-optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; electrical, optical, acoustical or other form of propagated signal (e.g., carrier waves, infrared signals, digital signals, etc.); or other type of medium suitable for storing electronic instructions. FIG. 15 depicts an exemplary system according to some realizations of the invention. A system 1500 includes a processor unit 1501 (possibly including multiple processors), system memory 1507A-507F (e.g., one or more of cache, SRAM DRAM, RDRAM, EDO RAM, DDR RAM, EEPROM, etc.), a system bus 1503 (e.g., LDT, PCI, ISA, etc.), a network interface 1505 (e.g., an ATM interface, an Ethernet interface, a Frame Relay interface, etc.), and a storage device(s) 1509A-1509D (e.g., optical storage, magnetic storage, etc.). Realizations of the invention may include fewer or additional components not illustrated in FIG. 15 (e.g., video cards, audio cards, additional network interfaces, peripheral devices, etc.). The processor unit 1501, the storage device(s) 1509A-1509D, the network interface 1505, and the system memory 1507A-1507F are coupled to the system bus 1503. The system memory 1507A-1507F embodies a directory distributor. Although FIG. 15 illustrates the directory distributor embodied in the system memory, various realizations of the invention implement the directory distributor differently (e.g., firmware, dedicated hardware, instantiation of one or more programs stored on the storage devices or another machine-readable medium, etc.). While the invention has been described with reference to various realizations, it will be understood that these realizations are illustrative and that the scope of the invention is not limited to them. Many variations, modifications, additions, and improvements are possible. For example, while much of the description herein has focused on the illustrative context of a directory distributor processing requests for a directory namespace backend, balancing requests across multiple directory distributors is also envisioned. Similarly, although individual read and write requests or single requests are presumed, techniques described herein may be generally applied to batch requests and hybrid requests. For example, based on the description herein, persons of ordinary skill in the art will appreciate decoding a hybrid read/write request into separate requests for appropriate routing. More generally, realizations in accordance with the present invention have been described in the context of particular realizations. These realizations are meant to be illustrative and not limiting. Accordingly, plural instances may be provided for components described herein as a single instance. Boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of claims that follow. Finally, structures and functionality presented as discrete components in the exemplary configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of the invention as defined in the claims that follow.
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<SOH> BACKGROUND <EOH>1. Field of the Invention The present invention relates to the field of information processing systems. More specifically, the present invention relates to distributed directory information. 2. Description of the Related Art Information directories are organized repositories of typically descriptive, attribute based information. An information directory may be an E-mail address directory, a telephone directory, a network directory, a public key directory, a company directory, etc. The International Standards Organization (ISO) and International Telecommunications Union (ITU) provided X.500 as a standard for organizing information directories and for directory services. The complexity of the X.500 standard deters many organizations from implementing the entire standard. In response to the comprehensiveness of X.500, the lightweight data access protocol (LDAP) was developed. LDAP is a set of protocols for accessing information directories. LDAP is based on some sections of X.500. In contrast to the X.500 standard that supports systems that conform to layer 7 of the OSI network reference model, LDAP supports systems that conform to layer 3/4 of the OSI network reference model. Universal Description, Discovery, and Integration (UDDI) is another directory related protocol. UDDI is a service discovery protocol for Web services. LDAP and similar standards define a hierarchical directory information tree with different levels for each category of information. A directory information tree has a root node, which contains information about the host directory server. The root node references containers or subdirectories. A container or subdirectory may include additional containers, or may include objects (also referred to as entries, leafs, etc.), which is a basic storage element of the directory information tree. A unique identifier (UID) names each object of an information directory tree. An object's distinguished name (DN) identifies the path from the root to the object and the unique identifier for the object. For example, assume a company maintains a directory information tree. The root node of the DIT indicates information about the directory server that hosts the DIT and the name of the company. The root node references two containers: 1) employees; and 2) customers. The employee container includes objects that indicate names, telephone numbers, and addresses of employees of the company. Likewise, the customer container includes objects that indicate the same information for customers of the company. The UID for each person, whether employee or customer, is their name. The DN for each customer would be the path to the customer object, which would include the company name (root node), the customer container, and the UID for the relevant customer. Users that access DITs make read type requests and write type requests. Write type requests include create operations, update operations, etc. Read type requests include search operations, compare operations, etc. Organizations typically allow anonymous users to have read type access to their DITs. Organizations typically do not allow such liberal access for writing to their DITs. In addition, certain branches of a DIT may be restricted from categories of users, especially anonymous users. To access restricted information or to perform restricted operations, a user is authenticated to the directory server that hosts the target information. Typically a directory server hosts security credentials of those users authorized to access the information on the directory server. Some DITs represent a massive amount of information. Storing all of the information for one of these large DITs overwhelms typical network resources. If a DIT includes hundreds of thousands of entries and is repeatedly accessed, performance of the host directory server suffers. In addition, throughput of the network conduit to the directory server is significantly impacted. Instead of storing an entire DIT on a single directory server, a DIT can be partitioned. A DIT is partitioned according to the organization of the DIT. Using the previous example, an employee directory server hosts all of the employee objects and a customer directory server hosts all of the customer objects. Unfortunately, DIT partitioning is confined by the organization of containers and does not address significant throughput and performance issues. Using the previous example, if there are a million customers and five hundred thousand employees for the company, partitioning the DIT still places a million objects on the customer directory server and half of a million objects on the employee directory server.
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<SOH> SUMMARY <EOH>Dividing a set of leaf objects having the same path of a directory namespace allows the divided path data sets to be distributed over separate physical stores. Distribution of divided path data sets over separate physical stores enhances scalability of a directory namespace and facilitates efficient utilization of resources. Leaf objects of a directory namespace are distributed in accordance with a given one or more distribution criteria. A representation of the distribution of leaf objects is utilizes to properly direct directory requests. According to some embodiments of the invention, an application directs directory requests to respective ones of separate stores that represent different sets of leaf objects of a directory namespace hierarchy, based at least in part on a distribution criteria. The different sets of leaf objects have a same directory path in the directory namespace hierarchy and the different leaf objects of the directory namespace hierarchy are distributed among the separate stores according to the distribution criteria. According to some embodiments of the invention, a method of processing directory requests for a distributed directory namespace comprises decoding at least part of a directory request to determine a value that corresponds to a distribution criteria. Sets of leaf objects having a same directory path in the directory namespace are distributed over separate stores in accordance with the distribution criteria. The method also comprises determining an appropriate one or more of the separate stores based at least in part on the value, and forwarding the directory request according to the determined appropriate one or more separate stores. According to some embodiments of the invention, a method for servicing directory requests for a directory namespace comprises determining if a directory request indicates a value that corresponds to a distribution criteria of the directory namespace. The directory namespace includes sets of leaf objects that are distributed among separate stores according to the distribution criteria. The sets of leaf objects have a same directory path. The method also comprises mapping the value to a first of the sets of leaf objects. According to some embodiments of the invention, a method comprises determining an appropriate one of a plurality of sets of leaf objects of a directory namespace for a directory request, the leaf objects of at least two of the plurality of sets of leaf objects having a same path in a directory namespace hierarchy. Each of the plurality of sets of leaf objects corresponds to a different one of a plurality of devices. The method also comprises forwarding the directory request to a first of the plurality of devices that corresponds to the determined appropriate one of the plurality of sets of leaf objects. According to some embodiments of the invention, an apparatus comprises a set of one or more processors, and a means for associating directory requests with corresponding ones of a plurality of separately stored sets of leaf objects. At least two sets of the plurality of sets of leaf objects have a same path in a directory namespace. According to some embodiments of the invention, a computer program product encoded on one or more machine-readable media comprises a first sequence of instructions to receive a directory request for a directory namespace, and a second sequence of instructions to direct the directory request to one of a plurality of separate stores, based at least in part on a value that corresponds to a distribution criteria. The directory namespace includes a plurality of leaf objects, which have a same directory path in the directory namespace, distributed over the plurality of separate stores. These and other aspects of the described invention will be better described with reference to the Description of the Preferred Embodiment(s) and accompanying Figures.
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20040702
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20121120
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20051027
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59939.0
| 0
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EL CHANTI, HUSSEIN A
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DIRECTORY DISTRIBUTOR
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,884,723
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ACCEPTED
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Buffer circuit and memory system for selectively outputting data strobe signal according to number of data bits
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Provided are a buffer circuit and a memory system for selectively outputting a data strobe signal according to the number of data bits. The buffer circuit includes a first buffer unit, a second buffer unit, and a third buffer unit. The first buffer unit amplifies and outputs a first signal. The second buffer unit amplifies and outputs a second signal or outputs the first signal according to the logic level of a control signal. The third buffer unit amplifies the first signal to send or not to send the amplified first signal to the second buffer unit depending on the logic level of an inverted control signal. The logic levels of the control signal and the inverted control signal are determined according to the number of processed data bits. When the number of processed data bits is n, the control signal is set to a first level and the inverted control signal is set to a second level, and when the number of processed data bits is k, the control signal is set to a second level and the inverted control signal is set to a first level. Since the buffer circuit and the memory system selectively output the data strobe signal according to the number of data bits, a point of time when the data are latched can be advanced and a setup/hold time of the data can be reduced.
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1. A buffer circuit for selectively outputting a data strobe signal according to a number of processed data bits, the buffer circuit comprising: a first buffer unit which amplifies and outputs a first signal; a second buffer unit which amplifies and outputs a second signal or outputs the first signal according to the logic level of a control signal; a third buffer unit which amplifies the first signal and either sends or does not send the amplified first signal to the second buffer unit depending on the logic level of an inverted control signal, wherein the logic levels of the control signal and the inverted control signal are determined according to the number of processed data bits. 2. The buffer circuit of claim 1, wherein the control signal is set to a first level and the inverted control signal is set to a second level when the number of processed data bits is n, and the control signal is set to the second level and the inverted control signal is set to the first level when the number of processed data bits is k. 3. The buffer circuit of claim 2, wherein n is 16 and k is 8 or 4. 4. The buffer circuit of claim 3, wherein the first signal and the second signal are data strobe signals. 5. The buffer circuit of claim 3, wherein the buffer circuit outputs both the first signal and the second signal when the data are n bits, and outputs only the first signal when the data are k bits. 6. The buffer circuit of claim 1, wherein the first buffer unit includes: a first differential amplifier which amplifies the first signal; a first inverter and a second inverter connected in series which buffer and output an output of the differential amplifier; a first transistor connected between the first inverter and a first voltage and having a gate to which an output of a third inverter for inverting the first voltage is applied; and a second transistor connected between the first inverter and a second voltage and having a gate to which the first voltage is applied. 7. The buffer circuit of claim 1, wherein the second buffer unit includes: a differential amplifier which amplifies the second signal; a first inverter and a second inverter connected in series, which buffer and output an output of the differential amplifier; a first transistor connected between the first inverter and a first voltage and having a gate to which an output of a third inverter for inverting the control signal is applied; and a second transistor connected between the first inverter and a second voltage and having a gate to which the control signal is applied, wherein the second inverter receives and outputs the first signal output from the third buffer unit when the control signal is at a second level. 8. The buffer circuit of claim 1, wherein the third buffer unit includes: a differential amplifier which amplifies the first signal; a first inverter which buffers an output of the differential amplifier and outputs the buffered output to the second buffer unit; a first transistor connected between the first inverter and a first voltage and having a gate to which an output of an second inverter for inverting the inverted control signal is applied; and a second transistor connected between the first inverter and a second voltage and having a gate to which the inverted control signal is applied. 9. The buffer circuit of claim 1, wherein the buffer circuit is mounted on a double data rate synchronous dynamic random access memory. 10. The buffer circuit of claim 1, wherein the control signal and the inverted control signal are signals generated by a pad bonding option. 11. A memory system for writing data to a memory array in response to a clock signal or reading out the data from the memory array, the memory system comprising: a buffer circuit which receives and outputs a first signal and a second signal in response to a control signal and an inverted control signal when the written or read data are n bits, and outputs the first signal in response to the control signal and the inverted control signal when the data are k bits; and a latch unit which latches the data in response to at least one of the first signal and the second signal and outputs the latched data to the memory array. 12. The memory system of claim 11, wherein the first signal and the second signal are data strobe signals. 13. The memory system of claim 11, wherein the control signal is set to a first level and the inverted control signal is set to a second level when the data are n bits, and the control signal is set to a second level and the inverted control signal is set to a first level when the data are k bits. 14. The memory system of claim 11, wherein n is 16, and k is 8 or 4. 15. The memory system of claim 11, wherein the memory system is a double data rate synchronous dynamic random access memory. 16. The memory system of claim 11, wherein the buffer circuit includes: a first buffer unit which amplifies and outputs the first signal; a second buffer unit which amplifies and outputs the second signal or outputs the first signal according to the logic level of the control signal; and a third buffer unit which amplifies the first signal and either sends or does not send the amplified first signal to the second buffer unit depending on the logic level of the inverted control signal, wherein the logic levels of the control signal and the inverted control signal are determined by the number of data bits.
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BACKGROUND OF THE INVENTION This application claims the priority of Korean Patent Application No. 2003-45395, filed on Jul. 4, 2003, in the Korean Intellectual Property Office, the contents of which are incorporated herein in their entirety by reference. 1. Field of the Invention The present invention relates to a semiconductor memory device, and more particularly, to a buffer circuit and a memory system which select a data strobe signal to output according to a number of data bits. 2. Description of the Related Art In general, data applied to a memory array are synchronized with a data strobe signal. FIG. 1 is a block diagram illustrating a process in which data to be applied to a memory array are synchronized with a data strobe signal. A data strobe signal is generally used to process data in units of bytes. Thus, to process data DATA of 16 bits, a 16-bit data strobe signal is divided into two 8-bit signals. One signal is an upper data strobe signal UDQS, and the other signal is a lower data strobe signal LDQS. When 16-bit data DATA is input, the upper data strobe signal UDQS latches an input of [8:15] data DATA, and the lower data strobe signal LDQS latches an input of [0:7] data DATA. When 16 bits of data DATA are input, the upper data strobe signal UDQS buffered by a first input buffer 110 is applied as an upper latch data strobe signal PUDQS to a latch unit 140 through a switching unit 130. The lower data strobe signal LDQS buffered by a second input buffer 120 is applied as a lower latch data strobe signal PLDQS to the latch unit 140 through the switching unit 130. The data DATA are synchronized with the upper and lower data strobe signals UDQS and LDQS and are applied to a memory array. However, when 8 bits of data DATA are input, the input 8 data are latched using 8 data strobe signals among 16 data strobe signals by a bonding option. Here, the upper data strobe signal UDQS, instead of the lower data strobe signal LDQS which is used as a reference signal for latching the 16 bits of data, generates the lower latch data strobe signal PLDQS through the switching unit 130. That is to say, when 16 bits of data are processed, the upper data strobe signal UDQS applies the upper latch data strobe signal PUDQS to the latch unit 140 and the lower data strobe signal LDQS applies the lower latch data strobe signal PLDQS to the latch unit 140. The input 16 bits of data DATA to be applied to the memory array are synchronized with the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. However, when 8 bits of data are processed, the upper data strobe signal UDQS applies the upper latch data strobe signal PUDQS to the latch unit 140, and also applies the lower latch data strobe signal PLDQS to the latch unit 140. The upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS are used as synchronizing signals of data DATA which are only input in units of 4 bits. In more detail, when the processed data DATA are 16 bits, a control signal CTRL input to the switching unit 130 is set to a first level, whereas when the processed data DATA are 8 bits, it is set to a second level. Thus, when the control signal CTRL is set to a first level, the switching unit 130 allows the upper data strobe signal UDQS to generate the upper latch data strobe signal PUDQS, and allows the lower data strobe signal LDQS to generate the lower latch data strobe signal PLDQS. However, when the control signal CTRL is set to a second level, the switching unit 130 allows the upper data strobe signal UDQS to generate both the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. Such an operation is performed when the input data DATA are 4 bits as well. That is, except the case where the input data DATa are 16 bits, the upper data strobe signal UDQS generates both the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. FIG. 2 is a block diagram of the switching unit shown In FIG. 1. Referring to FIG. 2, the switching unit 130 includes a first switch 210 which outputs the signal TUDQS obtained by buffering the upper data strobe signal UDQS by means of the first input buffer 110, a second switch 220 which outputs the buffered signal TUDQS as the lower latch data strobe signal PLDQS in response to an inverted control signal BCTRL, and a third switch 230 which receives the signal TLDQS obtained by buffering the lower data strobe signal LDQS by means of the second input buffer 120. When the received control signal CTRL is set to a first level and the received inverted control signal BCTRL is set to a second level, it means that the input data DATA are 16 bits. Therefore, the second switch 220 is turned off and the third switch 230 is turned on. Accordingly, the signal TUDQS obtained by buffering the upper data strobe signal UDQS by means of the first input buffer 110 is output as the upper latch data strobe signal PUDQS, and the signal TLDQS obtained by buffering the lower data strobe signal LDQS by means of the second input buffer unit 120 is output as the lower latch data strobe signal PLDQS. When the received control signal CTRL is set to a second level and the received inverted control signal BCTRL is set to a first level, it means that the input data DATA are 8 bits or 4 bits. Therefore, the second switch 220 is turned on and the third switch 230 is turned off. Accordingly, the signal TUDQS obtained by buffering the upper data strobe signal UDQS by means of the first input buffer 110 is output as the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. As mentioned, the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS are reference signals for latching the data DATA. When they are generated, if a separate switching circuit is added as shown in FIG. 1, speed is reduced and generation of the latched data DATA is delayed. Further, since generation of the latched data DATA is delayed, the amount of time required for the data DATA to be transferred to the memory array is also increased. As a result, write time is reduced and skew of the data strobe signal caused by the switching unit 130 increases, thereby lengthening a setup/hold time of the data DATA. SUMMARY OF THE INVENTION The present invention provides a buffer circuit for selectively outputting an input data strobe signal according to the number of data bits. The present invention provides a memory system with a buffer circuit for selectively outputting an input data strobe signal according to the number of data bits. According to an aspect of the present invention, there is provided a buffer circuit for selectively outputting a data strobe signal according to a number of processed data bits. The buffer circuit includes a first buffer unit, a second buffer unit, and a third buffer unit. The first buffer unit amplifies and outputs a first signal. The second buffer unit amplifies and outputs a second signal or outputs the first signal depending on the logic level of a control signal. The third buffer unit amplifies the first signal and either sends or does not send the amplified first signal to the second buffer unit depending on the logic level of an inverted control signal. The logic levels of the control signal and the inverted control signal are determined according to the number of processed data bits. The control signal may be set to a first level and the inverted control signal may be set to a second level when the number of processed data bits is n, and the control signal may be set to the second level and the inverted control signal may be set to the first level when the number of processed data bits is k. Here, n may be 16 and k maybe 8 or 4. The first signal and the second signal may be data strobe signals. The buffer circuit may output both the first signal and the second signal when the data are n bits, and may output only the first signal when the data are k bits. The first buffer unit may include: a first differential amplifier which amplifies the first signal; a first inverter and a second inverter connected in series which buffer and output an output of the first differential amplifier; a first transistor connected between the first inverter and a first voltage and having a gate to which an output of a third inverter for inverting the first voltage is applied; and a second transistor connected between the first inverter and a second voltage and having a gate to which the first voltage is applied. The second buffer unit may include: a second differential amplifier which amplifies the second signal; a fourth inverter and a fifth inverter connected in series which buffer and output an output of the second differential amplifier; a third transistor connected between the fourth inverter and a first voltage and having a gate to which an output of a sixth inverter for inverting the control signal is applied; and a fourth transistor connected between the fourth inverter and a second voltage and having a gate to which the control signal is applied, wherein the fifth inverter receives and outputs the first signal output from the third buffer unit when the control signal is at a second level. The third buffer unit may include: a third differential amplifier which amplifies the first signal; a seventh inverter which buffers an output of the third differential amplifier and outputs the buffered output to the second buffer unit; a fifth transistor connected between the seventh inverter and a first voltage and having a gate to which an output of an eighth inverter for inverting the inverted control signal is applied; and a sixth transistor connected between the seventh inverter and a second voltage and having a gate to which the inverted control signal is applied. The buffer circuit may be mounted on a double data rate synchronous dynamic random access memory. The control signal and the inverted control signal are signals generated by a pad bonding option. According to another aspect of the present invention, there is provided a memory system for writing data to a memory array in response to a clock signal or reading out the data from the memory array, the memory system comprising a buffer circuit and a latch unit. The buffer circuit receives and outputs a first signal and a second signal in response to a control signal and an inverted control signal when the written or read data are n bits, and outputs the first signal in response to the control signal and the inverted control signal when the data are k bits. The latch unit latches the data in response to at least one of the first signal and the second signal and outputs the latched data to the memory array. In one embodiment, the first signal and the second signal are data strobe signals. The control signal can be set to a first level and the inverted control signal can be set to a second level when the data are n bits, and the control signal can be set to a second level and the inverted control signal can be set to a first level when the data are k bits. In one embodiment, n is 16, and k is 8 or 4. ry system of claim 11, wherein the memory system is a double data rate synchronous dynamic random access memory. The buffer circuit can include: a first buffer unit which amplifies and outputs the first signal; a second buffer unit which amplifies and outputs the second signal or outputs the first signal according to the logic level of the control signal; and a third buffer unit which amplifies the first signal and either sends or does not send the amplified first signal to the second buffer unit depending on the logic level of the inverted control signal. The logic levels of the control signal and the inverted control signal can be determined by the number of data bits. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of the invention will be apparent from the more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. FIG. 1 is a block diagram illustrating a process in which data are synchronized with a data strobe signal to be applied to a memory array. FIG. 2 is a block diagram of a switching unit shown in FIG. 1. FIG. 3 is a circuit diagram of a buffer circuit according to an embodiment of the present invention. FIG. 4 is a block diagram of a memory system provided with the buffer circuit shown in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION FIG. 3 is a circuit diagram of a buffer circuit according to aan embodiment of the present invention. The buffer circuit in FIG. 3 replaces the first input buffer 110, the second input buffer 120 and the switching unit 130 of the conventional approach described in connection with FIG. 1. That is, the buffer circuit 300 of FIG. 3 receives the upper data strobe signal UDQS and the lower data strobe signal LDQS and outputs the upper latch data strobe signal PUDQS and lower latch data strobe signal PLDQS to the latch unit 410 (see FIG. 4) to process the input data DATA. The number of data bits n,k in the input data DATA to be processed is used by the buffer circuit 300 to generate the signals PUDQS and PLDQS in accordance with the following description. Referring to FIG. 3, the buffer circuit 300 includes a first buffer unit BF1, a second buffer unit BF2, and a third buffer unit BF3. The first buffer unit BF1 amplifies and outputs a first signal UDQS. The second buffer unit BF2 amplifies and outputs a second signal LDQS or outputs the first signal UDQS depending on the logic level of a control signal CTRL. The third buffer unit BF3 amplifies the first signal UDQS and either sends or does not send the amplified first signal to the second buffer unit BF2 depending on the logic level of an inverted control signal BCTRL. The logic levels of the control signal CTRL and the inverted control signal BCTRL are determined by the number of bits of processed data DATA. The operation of the buffer circuit according to the preferred embodiment of the present invention will be described in detail with reference to FIG. 3. The buffer circuit 300 shown in FIG. 3 can function as a conventional buffer for buffering a data strobe signal, and can also switch the data strobe signal according to the number of data bits in the data DATA. Thus, the switching unit 130 shown in the conventional latch structure shown in FIG. 1 can be omitted in FIG. 3 by employing the buffer circuit 300. The buffer circuit 300 includes the first buffer unit BF1, the second buffer unit BF2, and the third buffer unit BF3. The first buffer unit BF1 amplifies and outputs the first signal UDQS. The second buffer unit BF2 amplifies and outputs the second signal LDQS or outputs the first signal UDQS according to the logic level of the control signal CTRL. The third buffer unit BF3 amplifies the first signal UDQS and either sends or does not send the amplified first signal to the second buffer unit BF2 depending on the logic level of the inverted control signal BCTRL. The first through third buffer units BF1, BF2, and BF3 perform switching functions according to the logic level of the control signal CTRL. The logic levels of the control signal CTRL and the inverted control signal BCTRL are determined by the number of data bits in the data DATA. That is to say, when the number of bits of data DATA to be processed is n, the control signal CTRL is set to a first level and the inverted control signal BCTRL is set to a second level. When the number of bits of data DATA to be processed is k, the control signal CTRL is set to a second level and the inverted control signal BCTRL is set to a first level. Here, n is 16, and k is 8 or 4. The first signal UDQS and the second signal LDQS are data strobe signals. In particular, the first signal UDQS is an upper data strobe signal and the second signal LDQS is a lower data strobe signal. When the data DATA are 16 bits, the control signal CTRL is set to the first level and the inverted control signal BCTRL is set to the second level. In this situation, the inverted control signal BCTRL stops the operation of the third buffer unit BF3. Thus, the first buffer unit BF1 of the buffer circuit 300 amplifies the first signal UDQS and outputs the amplified first signal as an upper latch data strobe signal PUDQS. The second buffer unit BF2 of the buffer circuit 300 amplifies the second signal LDQS and outputs the amplified second signal as a lower latch data strobe signal PLDQS. When the data DATA are 8 bits or 4 bits, the control signal CTRL is set to the second level and the inverted control signal BCTRL is set to the first level. The control signal CTRL stops the operation of the second buffer unit BF2 and the inverted control signal BCTRL begins to operate the third buffer unit BF3. Therefore, the first buffer unit BF1 of the buffer circuit 300 amplifies the first signal UDQS and outputs the amplified first signal as the upper latch data strobe signal PUDQS. The third buffer unit BF3 of the buffer circuit 300 amplifies the first signal UDQS and applies the amplified first signal to the second buffer unit BF2. The second buffer unit BF2 outputs the received first signal UDQS as the lower latch data strobe signal PLDQS. The structures of the first through third buffer units BF1 through BF3 will be described in further detail. The first buffer unit BF1 includes a first differential amplifier DA1 for amplifying the first signal UDQS, a first inverter 11 and a second inverter 12 connected in series for buffering and outputting an output of the first differential amplifier DA1, a first transistor TR1 connected between the first inverter 11 and a first voltage VDD and having a gate to which an output of a third inverter 13 for inverting a first voltage VDD is applied, and a second transistor TR2 connected between the first inverter 11 and a second voltage VSS and having a gate to which the first voltage VDD is applied. The first inverter 11 is structured such that a P-channel metal oxide semiconductor (PMOS) transistor ITR1 and an N-channel metal oxide semiconductor (NMOS) transistor ITR2 are connected in series, and the second inverter 12 is structured such that a PMOS transistor ITR3 and an NMOS transistor ITR4 are connected in series. The first-transistor TR1 has a drain connected to a source of the PMOS transistor ITR1 of the first inverter 11 and a source connected to the first voltage VDD. The first voltage VDD is a power voltage. The third inverter 13 inverts the first voltage VDD and applies the inverted voltage to the first transistor TR1. The first transistor TR1 is a PMOS transistor. Therefore, the first transistor TR1 is always turned on. The second transistor TR2 has a drain connected to a source of the NMOS transistor ITR2 of the first inverter 11 and a source connected to the second voltage VSS. The second voltage VSS is a ground voltage. The first voltage VDD is applied to a gate of the second transistor TR2. The second transistor TR2 is an NMOS transistor. Accordingly, the second transistor TR2 is always turned on. Since the first buffer unit BF1 is always operated by the first voltage VDD, the first signal UDQS is always amplified by the first differential amplifier DA1 and is output as the upper latch data strobe signal PUDQS. The second buffer unit BF2 includes a second differential amplifier DA2 for amplifying the second signal LDQS, a fourth inverter 14 and a fifth inverter 15 connected in series for buffering and outputting an output of the second differential amplifier DA2, and a third transistor TR3 connected between the fourth inverter 14 and a first voltage VDD and having a gate to which an output of a sixth inverter 16 for inverting the control signal CTRL is applied. The second buffer unit BF2 further includes a fourth transistor TR4 connected between the fourth inverter 14 and a second voltage VSS and having a gate to which the control signal CTRL is applied. The fifth inverter 15 receives and outputs the first signal UDQS output from the third buffer unit BF3 when the control signal CTRL is at the second level. The third transistor TR3 of the second buffer unit BF2 has a drain connected to a source of a PMOS transistor ITR5 of the fourth inverter 14 and a source connected to the first voltage VDD. The sixth inverter 16 inverts the control signal CTRL and applies the inverted control signal to a gate of the third transistor TR3. The third transistor TR3 is a PMOS transistor. The fourth transistor TR4 has a drain connected to a source of an NMOS transistor ITR6 of the fourth inverter 14 and a source connected to the second voltage VSS. The control signal CTRL is applied to a gate of the fourth transistor TR4. The fourth transistor TR4 is an NMOS transistor. When the control signal CTRL is at the first level, the second buffer unit BF2 receives the second signal LDQS and outputs the received second signal as the lower latch data strobe signal PLDQS. When the control signal CTRL is at the second level, the second buffer unit BF2 cuts off the second signal LDQS and receives the output of the third buffer unit BF3 and outputs the received output as the lower latch data strobe signal PLDQS. The output of the third buffer unit BF3 is the first signal UDQS. When the input data DATA are 16 bits, the control signal CTRL is set to the first level, and when the input data DATA are 8 bits or 4 bits, the control signal CTRL is set to the second level. That is, the second buffer unit BF2 amplifies and outputs the second signal LDQS when the data DATA are 16 bits, whereas the second buffer unit BF2 receives and outputs the output of the third buffer unit BF3 when the data DATA are 8 bits or 4 bits. The third buffer unit BF3 includes a third differential amplifier DA3 for amplifying the first signal UDQS, a seventh inverter 17 for buffering an output of the third differential amplifier DA3 and outputting the buffered output to the second buffer unit BF2, a fifth transistor TR5 connected between the seventh inverter 17 and a first voltage VDD and having a gate to which an output of an eighth inverter 18 for inverting the inverted control signal BCTRL is applied, and a sixth transistor TR6 connected between the seventh inverter 17 and a second voltage VSS and having a gate to which the inverted control signal BCTRL is applied. The fifth transistor TR5 of the third buffer unit BF3 has a drain connected to a source of a PMOS transistor ITR9 of the seventh inverter 17 and a source connected to the first voltage VDD. The eighth inverter 18 inverts the inverted control signal BCTRL and applies the inverted control signal to a gate of the fifth transistor TR5. The fifth transistor TR5 is a PMOS transistor. The sixth transistor TR6 has a drain connected to a source of an NMOS transistor ITR10 of the seventh inverter 17 and a source connected to the second voltage VSS. The inverted control signal BCTRL is applied to a gate of the sixth transistor TR6. The sixth transistor TR6 is an NMOS transistor. When the inverted control signal BCTRL is at the first level, the third buffer unit BF3 receives the first signal UDQS and applies the received first signal to the second buffer unit BF2. When the inverted control signal BCTRL is at the second level, the third buffer unit BF3 cuts off the first signal UDQS. When the input data DATA are 16 bits, the inverted control signal BCTRL is set to the second level, and when the input data DATa are 8 bits or 4 bits, the inverted control signal BCTRL is set to the first level. That is, when the data DATA are 16 bits, the third buffer unit BF3 does not allow the first signal UDQS to be applied to the second buffer unit BF2, and when the data DATA are 8 bits or 4 bits, the third buffer unit BF3 receives the first signal UDQS and applies the received first signal to the second buffer unit BF2. The control signal CTRL and the inverted control signal BCTRL which control the second buffer unit BF2 and the third buffer unit BF3 are signals generated by a pad bonding option. That is, a wire bonding is differentiated according to whether the data DATA are 16 bits, or 8 or 4 bits to determine the level of the control signal CTRL. FIG. 4 is a block diagram of a memory system provided with the buffer circuit shown in FIG. 3. Referring to FIG. 4, a memory system 400 writes data DATA to a memory array in response to a clock signal (not shown) or reads the data DATA from the memory array. The memory system 400 includes a buffer circuit 300 and a latch unit 410. The buffer circuit 300 of FIG. 4 is the same as the buffer circuit shown in FIG. 3. When the data DATA are 16 bits, the buffer circuit 300 amplifies a first signal UDQS and outputs the amplified first signal as an upper latch data strobe signal PUDQS, and amplifies a second signal LDQS and outputs the amplified second signal as a lower latch data strobe signal PLDQS. The latch unit 410 latches the data DATA in response to the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS, and applies the latched data DATA to the memory array. A buffer 420 buffers the data DATA. When the data DATA are 8 bits or 4 bits, the buffer circuit 300 amplifies the first signal UDQS and outputs the amplified first signal as the upper latch data strobe signal PUDQS, and amplifies the first signal UDQS instead of the second signal LDQS and outputs the amplified first signal as the lower latch data strobe signal PLDQS. The latch unit 410 latches the data DATA in response to the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS, and applies the latched data DATA to the memory array. When being compared with the conventional memory system of FIG. 1, since the buffer circuit 300 performs the function of the switching unit 130, a speed drop in the data strobe signal caused by the switching unit 130 can be solved. The memory system of FIG. 4 can be used as a double data rate synchronous dynamic random access memory (DRAM). As described above, since the buffer circuit and the memory system select the data strobe signal to output according to the number of data bits, a point of time when the data are latched using the data strobe signal can be advanced, and a setup/hold time of the data can be reduced. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>This application claims the priority of Korean Patent Application No. 2003-45395, filed on Jul. 4, 2003, in the Korean Intellectual Property Office, the contents of which are incorporated herein in their entirety by reference. 1. Field of the Invention The present invention relates to a semiconductor memory device, and more particularly, to a buffer circuit and a memory system which select a data strobe signal to output according to a number of data bits. 2. Description of the Related Art In general, data applied to a memory array are synchronized with a data strobe signal. FIG. 1 is a block diagram illustrating a process in which data to be applied to a memory array are synchronized with a data strobe signal. A data strobe signal is generally used to process data in units of bytes. Thus, to process data DATA of 16 bits, a 16-bit data strobe signal is divided into two 8-bit signals. One signal is an upper data strobe signal UDQS, and the other signal is a lower data strobe signal LDQS. When 16-bit data DATA is input, the upper data strobe signal UDQS latches an input of [8:15] data DATA, and the lower data strobe signal LDQS latches an input of [0:7] data DATA. When 16 bits of data DATA are input, the upper data strobe signal UDQS buffered by a first input buffer 110 is applied as an upper latch data strobe signal PUDQS to a latch unit 140 through a switching unit 130 . The lower data strobe signal LDQS buffered by a second input buffer 120 is applied as a lower latch data strobe signal PLDQS to the latch unit 140 through the switching unit 130 . The data DATA are synchronized with the upper and lower data strobe signals UDQS and LDQS and are applied to a memory array. However, when 8 bits of data DATA are input, the input 8 data are latched using 8 data strobe signals among 16 data strobe signals by a bonding option. Here, the upper data strobe signal UDQS, instead of the lower data strobe signal LDQS which is used as a reference signal for latching the 16 bits of data, generates the lower latch data strobe signal PLDQS through the switching unit 130 . That is to say, when 16 bits of data are processed, the upper data strobe signal UDQS applies the upper latch data strobe signal PUDQS to the latch unit 140 and the lower data strobe signal LDQS applies the lower latch data strobe signal PLDQS to the latch unit 140 . The input 16 bits of data DATA to be applied to the memory array are synchronized with the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. However, when 8 bits of data are processed, the upper data strobe signal UDQS applies the upper latch data strobe signal PUDQS to the latch unit 140 , and also applies the lower latch data strobe signal PLDQS to the latch unit 140 . The upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS are used as synchronizing signals of data DATA which are only input in units of 4 bits. In more detail, when the processed data DATA are 16 bits, a control signal CTRL input to the switching unit 130 is set to a first level, whereas when the processed data DATA are 8 bits, it is set to a second level. Thus, when the control signal CTRL is set to a first level, the switching unit 130 allows the upper data strobe signal UDQS to generate the upper latch data strobe signal PUDQS, and allows the lower data strobe signal LDQS to generate the lower latch data strobe signal PLDQS. However, when the control signal CTRL is set to a second level, the switching unit 130 allows the upper data strobe signal UDQS to generate both the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. Such an operation is performed when the input data DATA are 4 bits as well. That is, except the case where the input data DATa are 16 bits, the upper data strobe signal UDQS generates both the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. FIG. 2 is a block diagram of the switching unit shown In FIG. 1 . Referring to FIG. 2 , the switching unit 130 includes a first switch 210 which outputs the signal TUDQS obtained by buffering the upper data strobe signal UDQS by means of the first input buffer 110 , a second switch 220 which outputs the buffered signal TUDQS as the lower latch data strobe signal PLDQS in response to an inverted control signal BCTRL, and a third switch 230 which receives the signal TLDQS obtained by buffering the lower data strobe signal LDQS by means of the second input buffer 120 . When the received control signal CTRL is set to a first level and the received inverted control signal BCTRL is set to a second level, it means that the input data DATA are 16 bits. Therefore, the second switch 220 is turned off and the third switch 230 is turned on. Accordingly, the signal TUDQS obtained by buffering the upper data strobe signal UDQS by means of the first input buffer 110 is output as the upper latch data strobe signal PUDQS, and the signal TLDQS obtained by buffering the lower data strobe signal LDQS by means of the second input buffer unit 120 is output as the lower latch data strobe signal PLDQS. When the received control signal CTRL is set to a second level and the received inverted control signal BCTRL is set to a first level, it means that the input data DATA are 8 bits or 4 bits. Therefore, the second switch 220 is turned on and the third switch 230 is turned off. Accordingly, the signal TUDQS obtained by buffering the upper data strobe signal UDQS by means of the first input buffer 110 is output as the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS. As mentioned, the upper latch data strobe signal PUDQS and the lower latch data strobe signal PLDQS are reference signals for latching the data DATA. When they are generated, if a separate switching circuit is added as shown in FIG. 1 , speed is reduced and generation of the latched data DATA is delayed. Further, since generation of the latched data DATA is delayed, the amount of time required for the data DATA to be transferred to the memory array is also increased. As a result, write time is reduced and skew of the data strobe signal caused by the switching unit 130 increases, thereby lengthening a setup/hold time of the data DATA.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides a buffer circuit for selectively outputting an input data strobe signal according to the number of data bits. The present invention provides a memory system with a buffer circuit for selectively outputting an input data strobe signal according to the number of data bits. According to an aspect of the present invention, there is provided a buffer circuit for selectively outputting a data strobe signal according to a number of processed data bits. The buffer circuit includes a first buffer unit, a second buffer unit, and a third buffer unit. The first buffer unit amplifies and outputs a first signal. The second buffer unit amplifies and outputs a second signal or outputs the first signal depending on the logic level of a control signal. The third buffer unit amplifies the first signal and either sends or does not send the amplified first signal to the second buffer unit depending on the logic level of an inverted control signal. The logic levels of the control signal and the inverted control signal are determined according to the number of processed data bits. The control signal may be set to a first level and the inverted control signal may be set to a second level when the number of processed data bits is n, and the control signal may be set to the second level and the inverted control signal may be set to the first level when the number of processed data bits is k. Here, n may be 16 and k maybe 8 or 4. The first signal and the second signal may be data strobe signals. The buffer circuit may output both the first signal and the second signal when the data are n bits, and may output only the first signal when the data are k bits. The first buffer unit may include: a first differential amplifier which amplifies the first signal; a first inverter and a second inverter connected in series which buffer and output an output of the first differential amplifier; a first transistor connected between the first inverter and a first voltage and having a gate to which an output of a third inverter for inverting the first voltage is applied; and a second transistor connected between the first inverter and a second voltage and having a gate to which the first voltage is applied. The second buffer unit may include: a second differential amplifier which amplifies the second signal; a fourth inverter and a fifth inverter connected in series which buffer and output an output of the second differential amplifier; a third transistor connected between the fourth inverter and a first voltage and having a gate to which an output of a sixth inverter for inverting the control signal is applied; and a fourth transistor connected between the fourth inverter and a second voltage and having a gate to which the control signal is applied, wherein the fifth inverter receives and outputs the first signal output from the third buffer unit when the control signal is at a second level. The third buffer unit may include: a third differential amplifier which amplifies the first signal; a seventh inverter which buffers an output of the third differential amplifier and outputs the buffered output to the second buffer unit; a fifth transistor connected between the seventh inverter and a first voltage and having a gate to which an output of an eighth inverter for inverting the inverted control signal is applied; and a sixth transistor connected between the seventh inverter and a second voltage and having a gate to which the inverted control signal is applied. The buffer circuit may be mounted on a double data rate synchronous dynamic random access memory. The control signal and the inverted control signal are signals generated by a pad bonding option. According to another aspect of the present invention, there is provided a memory system for writing data to a memory array in response to a clock signal or reading out the data from the memory array, the memory system comprising a buffer circuit and a latch unit. The buffer circuit receives and outputs a first signal and a second signal in response to a control signal and an inverted control signal when the written or read data are n bits, and outputs the first signal in response to the control signal and the inverted control signal when the data are k bits. The latch unit latches the data in response to at least one of the first signal and the second signal and outputs the latched data to the memory array. In one embodiment, the first signal and the second signal are data strobe signals. The control signal can be set to a first level and the inverted control signal can be set to a second level when the data are n bits, and the control signal can be set to a second level and the inverted control signal can be set to a first level when the data are k bits. In one embodiment, n is 16, and k is 8 or 4. ry system of claim 11 , wherein the memory system is a double data rate synchronous dynamic random access memory. The buffer circuit can include: a first buffer unit which amplifies and outputs the first signal; a second buffer unit which amplifies and outputs the second signal or outputs the first signal according to the logic level of the control signal; and a third buffer unit which amplifies the first signal and either sends or does not send the amplified first signal to the second buffer unit depending on the logic level of the inverted control signal. The logic levels of the control signal and the inverted control signal can be determined by the number of data bits.
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20040702
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20061017
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20050526
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73113.0
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NGUYEN, DANG T
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BUFFER CIRCUIT AND MEMORY SYSTEM FOR SELECTIVELY OUTPUTTING DATA STROBE SIGNAL ACCORDING TO NUMBER OF DATA BITS
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UNDISCOUNTED
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ACCEPTED
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10,884,729
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ACCEPTED
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Protein inhibiting aggregation of beta amyloid peptide
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The present invention relates to a novel protein inhibiting β amyloid aggregation and a strain producing the protein, more precisely, to a novel protein inhibiting β amyloid aggregation, a gene coding the protein, a Streptomyces sp. strain producing the protein and a therapeutic agent for neurodegenerative disorders containing the protein as an effective ingredient. The therapeutic agent of the present invention containing the protein inhibiting β amyloid aggregation as an effective ingredient can be effectively used for the prevention and the treatment of neurodegenerative disorders like Alzheimer's disease.
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1. A β-amyloid aggregation inhibiting protein having an amino acid sequence represented by SEQ. ID. No 3. 2. A gene coding the protein of claim 1. 3. The gene as set forth in claim 2, wherein the gene has a nucleotide sequence represented by SEQ. ID. No 4. 4. A Streptomyces sp. strain producing the protein of claim 1. 5. The strain as set forth in claim 5, wherein the strain is Streptomyces sp. KK565 (Accession No: KCCM-10485). 6. A therapeutic agent for neurodegenerative disorders containing the protein of claim 1 as an effective ingredient. 7. The therapeutic agent as set forth in claim 6, wherein the agent is used for Alzheimer's disease or Down syndrome.
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FIELD OF THE INVENTION The present invention relates to a novel protein inhibiting β amyloid aggregation and a strain producing the protein, more precisely, to a novel protein inhibiting β amyloid aggregation, a gene coding the protein, a Streptomyces sp. strain producing the protein and a therapeutic agent for neurodegenerative disorders containing the protein as an effective ingredient. BACKGROUND Alzheimer's disease (referred as “AD” hereinafter) is a debilitating neurodegenerative disorder in the elederly effecting millions of individuals throughout the world. One of the pathological hallmarks of AD is the extracellular protein deposits referred as senile plaques (Geula, C. et al., Nat. Med., 4, 827-831 (1998)) that consist predominantly of an aggregated peptide known as β amyloid (referred as “Aβ” hereinafter). Aβ, 39-43 amino acid peptides, is produced through proteolytic processing of the β amyloid precursor protein (referred as “βAPP” hereinafter) by β-secretase and γ-secretase (Glenner, G. G. et al., Biochim. Biophys. Res. Commun., 120, 885-890 (1984); Yasojima, K. et al., Neurosci. Lett., 12, 97-100 (2001)). This peptide is particularly amyloidogenic and appears to form the core of the neuritic plaques. The number of plaques appears to correlate with the degree or severity of the dementia (Hasse, C. et al., Cell, 75, 1039-1042 (1993); Selkoe, D. J., J. Neuropathol. Exp. Neurol., 53, 438-447 (1994)). In addition, fibrillar Aβ, amorphous aggregates of Aβ, has been reported to cause neuronal cell death in primary rat hippocampal cultures whereas soluble monomeric species of Aβ are relatively less toxic than fibrillar Aβ (Yankner, B. A. et al., Science, 250, 279-282 (1990)). Other studies suggested that prefibrillar aggregates of Aβ are neurotoxic (Zhu, Y. J. et al., FASEB J., 14, 1244-1254 (2000)). Mutations in genes of either APP or presenilins (PS), which seemed to have a γ-secretase activity, may lead to elevation of the production of Aβ, and are associated with severe and early-onset forms of AD (Yoshiike, Y. et al., J. Biol. Chem., 276, 32293-32299 (2001)). Taken together, Aβ aggregation is considered as a crucial event in the pathogenesis of AD. Accordingly, the efficient inhibition of Aβ aggregation is considered as a powerful way to prevent or treat AD. Therefore, extensive studies have been carried out to discover anti-amyloidogenic compounds from natural or synthetic sources. Several low molecular weight compounds such as antioxidants, free radical scavengers, cholesterol lowering drugs, calcium channel blockers, and γ-secretase inhibitors have been developed as a therapeutic agent for AD (Selkoe, D. J., Physiol. Res., 81, 741-766 (2001)). Among these compounds, γ-secretase inhibitors are known to decrease Aβ production 30-40% (Schroeter, E. H. et al., Nature., 393, 382-386 (1989); Vandermeeren, M. et al., Neurosci Lett., 27, 145-148 (2001)). Among high molecular weight compounds, anti-Aβ antibody, a macromolecular protein, is a good example to enhance clearing of Aβ deposits in transgenic mice that already had begun to develop plaques, possibly by the recruitment of local microglia (Schenk, D. et al., Nature, 400, 173-177 (1999)). Recently, neprilysin which is also known as enkephalinase as well as the common acute lymphoblastic leukemia antigen (CALLA) has been confirmed to be involved in degradation of Aβ-amyloid by its proteolytic activity (Iwata, N. et al., Nat Med., 6, 718-719 (2000); Iwata, N. et al., Science, 292, 1550-1552 (2001)). Moreover, reduced neprilysin level in the plaque area of AD brain was found, suggesting that reduced degradation of Aβ caused by low levels of neprilysin may contribute to AD pathogenesis (Yasojima, K. et al., Neurosci Lett., 12, 97-100 (2001)). In addition, Eckman et al. reported recently that endothelin-converting enzyme-1 (ECE-1) degraded Aβ in vitro at multiple sites (Eckman, E. A. et al., J. Biol. Chem. 27, 24540-24548 (2001)). These results demonstrate that the endogenous concentration of Aβ peptides is regulated not only by its production but also by its catabolism with a specific proteolytic peptidase. Nevertheless, there is something yet to learn about not only high molecular weight compounds inhibiting neurotoxicity caused by Aβ peptide but also a therapeutic agent for neurodegenerative disorders using a high molecular weight biomolecule without side effects by low molecular weight. Thus, the present inventors separated a Streptomyces sp. strain as a target strain producing an active protein inhibiting the aggregation of Aβ peptide inducing AD, and completed this invention by verifying that a protein separated from the strain could be used as a therapeutic agent for neurodegenerative disorders. SUMMARY OF THE INVENTION It is an object of this invention to provide a novel protein inhibiting β amyloid aggregation, a gene coding the protein, a Streptomyces sp. strain producing the protein and a therapeutic agent for neurodegenerative disorders containing the protein as an effective ingredient. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In order to achieve the above object, the present invention provides a novel protein inhibiting Aβ aggregation having an amino acid sequence represented by SEQ. ID. No 3. The present invention also provides a gene coding the protein. The present invention further provides a Streptomyces sp. strain producing the protein. The present invention also provides a therapeutic agent for neurodegenerative disorders containing the protein as an effective ingredient. Hereinafter, the present invention is described in detail. The present invention provides a novel protein having β amyloid aggregation blocking activity (referred as ‘AABA’ hereinafter) and an amino acid sequence represented by SEQ. ID. No 3. The Aβ aggregation blocking activity of the protein was confirmed by Congo red assay (FIG. 2a) and thioflavin T (Th-T) fluorescence assay (FIG. 2b). The. protein prevents the neuronal cell death induced by the aggregated Aβ. The molecular weight of the protein of the invention was approximately 45 KDa and base sequence of the protein was identified by IPCR (inverse polymerase chain reaction), based on its cDNA construct. So, the protein of the present invention was confirmed at last to be a protein having an amino acid sequence represented by SEQ. ID. No 3. The protein of the present invention having an amino acid sequence represented by SEQ. ID. No 3 consists of three major domains, that is ala-rich domain (11th-86th amino acid), M20 domain (132nd-192nd amino acid) and P domain (318th-410th amino acid) M20 domain has an activity of aminopeptidase, and P domain might be involved in intramolecular cleavage taking place in N-terminal of a proprotein. Therefore, the protein of the present invention is expected to have the function of a protease. The protein of the present invention having AABA is assumed to be an active protein converted from a proprotein that was cut by P domain in front of alanine, the 39th amino acid residue of the amino acid sequence represented by SEQ. ID. No 3. The reason for the assumption is that sequence after the 39th amino acid residue of the base sequence represented by SEQ. ID. No 3 is equal to base sequence represented by SEQ. ID. No 5 which was confirmed to be N-terminal amino acid sequence of the separated protein. In addition, the 30th-38th amino acid region (APASRTAAA) of base sequence represented by SEQ. ID. No 3 was also very similar to amino acid sequence represented by SEQ. ID. No 9 (APASRTAASMS), a general cleavage site. The present invention also provides a gene coding the AABA protein. It is preferred for the gene to have a nucleotide sequence represented by SEQ. ID. No 4. Nucleotide sequence of the gene coding AABA protein represented by SEQ. ID. No 3 is composed of 1404 nucleotides (see SEQ. ID. No 4). The starting codon of the gene coding amino acid of the above protein begins with the 91nd nucleotide (ATG). Coding of the above protein is completed at TGA, a termination codon (1402nd-1404th nucleotide). The present invention also provides a Streptomyces sp. strain producing the protein. And it is preferred for the strain to be a Streptomyces sp. strain KK565 (Accession No: KCCM-10485). In order to identify a strain producing an Aβ peptide aggregation inhibitor, the present inventors performed screening of microorganism metabolites. As a result, in variety of microorganisms producing compounds and proteins having biological activities were isolated. Among them, a microorganism producing a protein that has the highest Aβ aggregation inhibiting activity was named as KK565. In order to characterize the above strain KK565, physiochemical characteristics of the strain were examined and taxonomic position thereof was also investigated. Precisely, the strain KK565 forms spores shaping a chain. The spore is spiral and has soft surface. Each spore is shaped like a rod (0.4-0.7×0.8-1.0 um) and non-mobile. The number of spores in a chain is 30-50 or more (see FIG. 3 and Table 1). The KK565 strain grew well in all media tested except inorganic salt-starch and peptone-yeast extract containing agar medium (see Table 2). L-arabinose, D-fructose, raffinose, and D-galactose were utilized by the KK565 strain as a carbon source. The strain has diaminopimelic acid in cell wall verified by the analysis of Becker's method (see Table 3). From the above results, the present inventors concluded the KK565 strain belongs to a Streptomyces species and named it Streptomyces sp. KK565. The strain was deposited at Korean Culture Center of Microorganisms (KCCM), on Apr. 9, 2003 (Accession No: KCCM-10485). The present invention also provides a therapeutic agent for neurodegenerative disorders containing the protein as an effective ingredient. The therapeutic agent of the present invention is preferably used for AD or Down syndrome, but not always limited thereto. The protein of the present invention having an amino acid sequence represented by SEQ. ID. No 3 can inhibit plaque formation or remove plaque deposited already, which is a characteristic cause of neurodegenerative disorders, by inhibiting Aβ peptide aggregation. The therapeutic agent of the present invention can be administered orally or parenterally and be used in general form of pharmaceutical formulation. The therapeutic agent for neurodegenerative disorders containing AABA protein of the present invention can be prepared for oral or parenteral administration by mixing with generally used fillers, extenders, binders, wetting agents, disintegrating agents, diluents such as surfactant, or excipients. Solid formulations for oral administration are tablets, pill, dusting powders and capsules. These solid formulations are prepared by mixing with one or more suitable excipients such as starch, calcium carbonate, sucrose or lactose, gelatin, etc. Except for the simple excipients, lubricants, for example magnesium stearate, talc, etc, can be used. Liquid formulations for oral administrations are suspensions, solutions, emulsions and syrups, and the above-mentioned formulations can contain various excipients such as wetting agents, sweeteners, aromatics and preservatives in addition to generally used simple diluents such as water and liquid paraffin. Formulations for parenteral administration are sterilized aqueous solutions, water-insoluble excipients, suspensions, emulsions, and suppositories. Water insoluble excipients and suspensions can contain, in addition to the active compound or compounds, propylene glycol, polyethylene glycol, vegetable oil like olive oil, injectable ester like ethylolate, etc. Suppositories can contain, in addition to the active compound or compounds, witepsol, macrogol, tween 61, cacao butter, laurin butter, glycerinated gelatin, etc. In general, it has proved advantageous both in human and in veterinary medicine to administer the active compound or compounds according to the present invention in total amounts of about 1˜100 mg/kg, preferably 5˜50 mg/kg of body weight, one to three times every 24 hours, if appropriate, in the form of several individual doses, to achieve the desired results. BRIEF DESCRIPTION OF THE DRAWINGS The application of the preferred embodiments of the present invention is best understood with reference to the accompanying drawings, wherein: FIG. 1 is a graph showing the time course of aggregation of β amyloid (referred as ‘Aβ’ hereinafter) 1-40 peptide having an amino acid sequence represented by SEQ. ID. No 1. Aβ aggregation was measured by the Congo red assay. --▪-- −Aβ: Reaction mixture in which Aβ1-40 peptide (100 μM) is included, --o-- +Aβ: Reaction mixture in which Aβ1-40 peptide (100 μM) is not included, FIG. 2a is a graph showing the effect of microbial metabolites on Aβ1-40 aggregation and fibril formation examined by the Congo red assay. □ −Aβ: Reaction mixture in which only test sample is included (Positive control), ▪ +Aβ: Reaction mixture in which Aβ1-40 peptide (100 μM) and test sample are included, Aβ: Control in which test sample is not included, 260˜715: Experimental groups having metabolites produced by each strain of the number, FIG. 2b is a graph showing the effect of microbial metabolites on Aβ1-40 aggregation and fibril formation examined by the thioflavin-T fluorescence assay. □−Aβ: Reaction mixture in which only test sample is included (Positive control), ▪+Aβ: Reaction mixture in which Aβ1-40 peptide (100 μM) and test sample are included, Aβ: Control in which test sample is not included, 260˜715: Experimental groups having metabolites produced by each strain of the number, FIG. 3 is a photograph showing the electron scanning morphology of Streptomyces sp. KK565 strain of the present invention in SEM (×2300). Bar scale represents 10 μm, FIG. 4 is a graph showing the effect of heat treatment on the Aβ aggregation blocking activity (AABA) of active compound (SEQ. ID. No 3). The activity was determined by Congo red assay, □ −Aβ: Reaction mixture in which only test sample is included (Positive control), ▪ +Aβ: Reaction mixture in which Aβ1-40 peptide (100 μM) and test sample are included, −Aβ/heat: Reaction mixture in which only heated test sample is included, +Aβ/heat: Reaction mixture in which Aβ1-40 peptide (100 μM) and heated sample are included, Aβ(MeOH): Control group in which methanol is used as a test sample, 565-70%: Experimental group in which 70% methanol fraction of a microbial sample (Streptomyces sp. KK565) is used, FIG. 5 is a photograph showing the molecular weight of a purified active compound in SDS-PAGE (Arrow indicates the AABA protein), Lane 1: Molecular weight marker, Lane 2: AABA protein purified from Streptomyces sp. KK565 strain, FIG. 6 is a graph showing the protection of neuronal cells from Aβ-induced death by active protein purified from Streptomyces sp. KK565 strain (Each bar represents the mean+SEM of three wells). MeOH: Methanol, KK565: AABA protein purified from Streptomyces sp. KK565 strain, KK595: Substance purified from Streptomyces sp. KK565 strain, Aβ(1-40): Aβ1-40 peptide (100 μM), Aβ(25-35): β amyloid 25-35 peptide having an amino acid sequence represented by SEQ. ID. No 2. EXAMPLES Practical and presently preferred embodiments of the present invention are illustrative as shown in the following Examples. However, it will be appreciated that those skilled in the art, on consideration of this disclosure, may make modifications and improvements within the spirit and scope of the present invention. Example 1 Identification of a Strain Producing AABA Protein In order to identify a strain producing a substance having AABA, the present inventors performed screening of microbial metabolites (Nam, J. Y. et al., J. Microbiol. Biotech., 10, 544-546 (2000); Kwon, H. J. et al., J. Microbiol. Biotech., 11, 1018-1023 (2001)) as follows. As a result, a biological compound and a protein having AABA were separated from in variety of microorganisms. To investigate the activity of the compound and the protein separated above, the present inventors applied both Congo red method (Klunk, W. E. et al., J. Histochem. Cytochem., 37, 1273-1281 (1989); Klunk, W. E. et al., Anal. Biochem., 266, 66-76 (1999) in which use a dye, Congo red, binding highly with β-s, he-et structure of amyloid presented in the below Example <1-1-1> and thioflavin-T (Th-T) assay (LeVine, H., Protein Sci., 2, 404-410 (1993)) that uses a fluorescent dye, thioflavin-T, binding with fibrous structures presented in the below Example <1-1-2>. <1-1> Fibrillogenesis Assay A microorganism library was constructed as follows. About 2,000 microorganisms were cultured on plate media. Some of them were collected from soil in Seoul and Kyunggido, and others were provided by Korea Research Institute of Bioscience and Biotechnology (KRIBB). Each 500 ml Erlenmeyer flask containing 50 ml of medium for stock culture (glucose 2%, yeast extract 0.2%, peptone 0.5%, KH3PO4 0.1% and MgSO4.7H2O 0.05%) was inoculated with two agar pieces for stock culture of the separated strains. The prepared stock solution was poured in 1 l Erlenmeyer flask containing 150 ml of medium for production (soluble starch 2%, bacto-soytone 0.4%, Phama medium 0.5%, KH3PO4 0.1%, MgSO4.7H2O 0.05%, NaCl 0.2% and CaCO3 0.3%). pH of the medium was adjusted to 6.0 with 1 N NaOH and the medium was autoclaved, followed by inoculation of strains. After inoculation, the bacteria were cultured for 5 days and the culture solution was recovered. Centrifugation with the culture solution was performed and supernatant was extracted by methanol. Metabolites were extracted from each microorganism. Among the extracts, a compound or a protein having AABA was hunted. Aβ peptide (1-40 or 25-35) (QCM, MA, Hopkinton) was dissolved in DMSO as concentrated stock solution (1.68 mM) prior to an experiment and the stock solution was then added to PBS buffer (phosphate buffer saline; 100 mM NaCl, 10 mM NaH2PO4, pH 7.4). The final concentration of Aβ was 100 μM. The mixed Aβ solution was incubated in the presence or absence of library (Nam, J. Y. et al., J. Microbiol. Biotech., 10, 544-546 (2000)) supernatants at 37° C. for up to 144 hours. The amount of Aβ fibrils remaining intact was measured by the Congo red assay or thioflavin T (Th-T) fluorescence assay as described below. <1-1-1> Congo Red Assay Congo red assay was used to examine the degree of Aβ aggregation. To determine the optimum condition for readily detectable accumulating level of Aβ aggregates, the present inventors performed a time course experiment of Aβ aggregation at 37° C. FIG. 1 showed the time course of Aβ peptide aggregation at 37° C. without any test agent using Congo red assay. Aβ aggregates were begun to form on day 4 and reached maximum on day 5 or day 6 (FIG. 1). Thus, the present inventors performed aggregation assay by incubating Aβ routinely for 5 days at 37° C. in this invention. Particularly, Aβ peptide and buffer were incubated for 5 days at 37° C. to allow fibril formation. Congo red was then added to each sample which was incubated for 30 minutes at room temperature. At this point, the optical density (OD) of each sample was measured using a UV spectrophotometer at a wavelength of 540 and 480 nm to assay Congo red binding with Aβ peptide. The quantity of Congo red binding (Cb) Aβ was calculated as follow: Cb [ M ] = OD 540 25 , 295 - OD 480 46 , 306 Background signals were determined by measuring the OD of “blank” containing both Aβ and library prior to calculating the total aggregation. <1-1-2> Thioflavin T Fluorescence Assay The degree of Aβ-aggregation was determined using fluorescent dye, thioflavin T (Th-T), which specially binds to fibrous structures. First, Aβ peptide stock solution was diluted with 50 mM sodium phosphate buffer, pH 6.0. Th-T was added to each test sample to a final concentration of 10 μM. The activity was measured at an excitation wavelength of 450 nm and an emission of 482 nm that resulted in the optimum detection of bound Th-T. To account for background fluorescence, the fluorescence intensity measured from each control solution without Aβ peptide was subtracted from that of each solution containing Aβ peptide. The fluorescence spectra of Aβ1-40 peptide from different commercial sources and from different lots were in good agreement. <1-2> Isolation of KK565 To isolate an active compound that has an Aβ aggregation-inhibitory activity, the present inventors applied both Congo red method which uses a dye, Congo red, binding highly with peptide of the Example <1-1-1> or protein aggregation and Th-T assay that uses a fluorescent dye, thioflavin-T, binding with fibrous structures of the Example <1-1-2>. Particularly, Aβ peptide was incubated for 5 days at 37° C. to allow fibril formation as described above. The anti-amyloidogenic activity of libraries was measured by adding 5% cultural broth of microbial libraries prepared in the Example <1-1> into Aβ aggregation solution in 96 well plate. From the 2,000 microbial metabolite libraries, a substance showing AABA activity both in Congo red (93.2% inhibition compared to control) and thioflavin-T (97% inhibition compared to control) was confirmed (FIGS. 2a and 2b). FIG. 2a and FIG. 2b show a part of the metabolite library, in which each number presents the designated number of a strain producing a test sample. The present inventors named a microorganism showing the highest AABA, among the selected microorganisms, KK565. Example 2 Identification of KK565 The KK565 strain was cultured on a tryptic soy broth (17.0 g pancreatic digest of casein, 3.0 g papaic digest of soybean meal, 5.0 g sodium chloride, 2.5 g dipotassium phosphate, 2.5 g dextrose and 1 l H2O, adjusted to pH 7.3 before autoclaving) for 7 days at 28° C. using a rotary-shaking incubator. The classification and identification of the cultured KK565 strain was carried out on the basis of ISP (International Streptomyces Project) method. <2-1> Morphological Characteristics The spore chain morphology of KK565 was examined as follow. The KK565 strain was incubated for 14 days on a yeast extract-malt extract agar (ISP medium 2) (4.0 g yeast extract, 10.0 g malt extract, 4.0 g dextrose, 20.0 g agar and 1 l H2O, adjusted to pH 7.3 before autoclaving). The spore chain morphology of the strain was examined using light and scanning electron microscopy (SEM). The morphological character of KK565 was investigated by optical and electron microscope using 14 day-cultured cells (Table 1). TABLE 1 Morphological characteristics of strain KK565 Spore surface Smooth Spore chain morphology Spiral Spore size 0.4-0.7 × 0.8-1.0(μm) Spore mobility None Spore number per chain >30-50 A spore chain showed spiral morphology and the superficies of spore in smooth. The shape of spore was rod with a length, 0.4-0.7×0.8-1.0 μm (FIG. 3). <2-2> Cultural Characteristics The cultural character of KK565 was investigated using several ISP media condition with 21 day-cultured cells. The strain grew well in all media tested except inorganic salt-starch and peptone-yeast extract containing agar medium (Table 2). TABLE 2 Cultural characteristics of KK565 Aerial Substrate Media Growth mycelium mycelium Yeast extract-malt Good Gray Pinkish extract agar (ISP No. 2) Oatmeal agar (ISP No. 3) Good Gray Pale Yellow Glycerol-asparagine Moderate Pinkish Pale agar (ISP No. 4) Gray Yellow Inorganic salt-starch Good White Pale agar (ISP No. 5) Yellow Peptone-yeast extract Moderate Poor Pale agar (ISP No. 6) Yellow Tyrosine agar Good White Pale (ISP No. 7) Yellow Glucose-asparagine agar Good Gray Pale Yellow Bennet's agar Good White Pale Yellow Nutrient agar Moderate White Pale Brown <2-3> Physiological Characteristics The possibility of using L-arabinose, D-fructose, raffinose and D-galactose as a carbon source to analyze physiochemical characteristics of KK565 strain was investigated. The type of 2,6-diaminopimelic acid (referred as “DAP” hereinafter), one of cell wall constituents of Streptomyces sp. Strain, was also investigated by Becker's method (Becker, B. et al., Appl. Microbiol., 13, 236 (1965)). As a result, it was confirmed based on the analysis of Becker's method that the strain has DAP in cell wall (Table 3). TABLE 3 Physiological characteristics of KK565 Utilization of C-source Starch hydrolysis + D-fructose + Skim milk hydrolysis − Galactose − Nitrate reduction − Inositol + Gelatin liquefaction − Mannitol − Melanin pigment − Raffinose + Soluble pigment − Rhamnose − Milk coagulation − Sucrose − Diaminopimelic acid LL D-xylose + D-glucose − L-arabinose + Cellulose − From the above results, the present inventors concluded the KK565 strain belongs to a Streptomyces species and named it Streptomyces sp. KK565. The strain was deposited at Korean Culture Center of Microorganisms (KCCM), on Apr. 9, 2003 (Accession No: KCCM-10485). Example 3 Protection of Neuronal Cells from Aβ-Induced Death by AABA Protein Produced by Streptomyces sp. KK565 Aβ aggregate is known to induce neuronal cell death as one of its biological activities. Accordingly, KK565 extract could prevent Aβ-induced neuronal cell death if it would block the aggregation of Aβ peptide. To verify this possibility, the present inventors examined the effect of KK565 extract on the viability of neuronal cells treated with Aβ peptide. Cell viability was assessed by a modified 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (referred as “MTT” hereinafter). Particularly, human neuroblastoma cells, SHSY-5Y (American Type Culture Collection, Rockville, Md.), were plated at the density of 2.5×104 in 96 well plates and cultured in the growth media, DMEM/F12 (Gibco BRL) containing 10% fetal calf serum, 2 mM glutamine and 1% penicillin/streptomycin, at 37° C., in the 5% CO2/95% O2 incubator. Aβ1-40(100 μM) was prepared under the condition of 100 mM NaCl, 10 mM NaH2PO4, pH 7.4. Supernatant of KK565 or KK595 (a library strain belongs to Streptomyces sp.) culture solution was treated with methanol, resulting in extract. Mixtures containing Aβ1-40 peptide (100 uM) and KK565 or KK595 strain were incubated at 37° C. for 6 days and added into the SHSY-5Y human neuronal cell cultures (final concentration of Aβ: 25 μM). In the meantime, Aβ25-35 (100 μM) was not pre-reacted with the strain extract above before being mixed with SHSY-5Y human neuronal cell culture solution. KK595 showing no Aβ aggregation-inhibitory activity from the Congo red assay was used as a negative control. After incubation for 24 hours, the cells were processed for MTT assay. MTT assay was performed as follow. The neuronal cells were treated for 24 hours with Aβ (1-40 or 25-35) which had been preincubated with a mixture of compounds for 6 days at 37° C. The cells were rinsed with PBS and then 10 μl of the MTT (0.5 mg/ml) was added. After the incubation for 4 hours, 100 μl of solution containing SDS(10%) and HCl(0.01 N) was added and incubated overnight. On the next day, absorption values of 550 nm were determined with an automatic microtiter plate reader. As a result, it was confirmed that the viability of neuronal cells reduced as much as 50% not only by the treatment of fibrillar Aβ1-40 but also by the treatment of Aβ25-35 (25 μM) (FIG. 6). This result indicates that Aβ25-35 having an amino acid sequence represented by SEQ. ID. No 2 acts as an important factor for Aβ aggregation and the Aβ25-35 peptide motifs are reacted with neuronal cells. KK565 significantly blocked Aβ-induced cell death (cells survived 20% more than those of a control) while KK595, a negative control, did not protect the neuronal cells. The viability of neuronal cells was not affected at all by the treatment of KK565 alone, suggesting that KK565 has no effect on cell proliferation. These data demonstrate that an active principle of KK565 inhibits the aggregation of Aβ peptide and suggest a possibility that the active principle of KK565 can be developed as a therapeutic agent for neurodegenerative disorders like Alzheimer's disease. Example 4 Purification and Identification of Anti-Amyloidogenic Compound from Streptomyces sp. KK565 Culture Broth <4-1> Culture of KK565 The anti-amyloidogenic compound producer, KK565, was grown and maintained at 28° C. on a YS medium plate (soluble starch 10 g/L, yeast extract 2 g/L, agar 20 g/L). For seed cultivation, an agar piece of the stock plate was cut under sterile conditions and incubated into a 500 ml baffle flask containing 50 ml of the culture medium (G.S.S.)(soluble starch 10 g/l, glucose 20 g/l, soy bean meal 25 g/l, yeast extract 4 g/l, NaCl 2 g/l, K2HPO4 0.25 g/l, CaCO3 2 g/l). The pH was adjusted to 7.2 with 1 M NaOH. The flask was cultivated for 48 fours at 28° C. on the rotary shaking incubator (150 rpm) and then the culture broth was transferred to 2 l baffle flasks containing the same medium (400 ml/flask) for large-scale cultivation. All flasks were cultured for 7 days at 28° C. <4-2> Purification and Identification of Anti-Amyloidogenic Compound The mycelia were separated from the culture broth by centrifugation (500 rpm, 30 min). The broth was extracted with the same volume of n-butanol and the water-soluble fraction extracted with n-butanol was applied to Diaion HP-20 column. Then, the column was washed with 30% methanol and was eluted with 50%, 70% and 100% methanol in a batch-wise manner. The active 70% ethanol fraction was concentrated in vacuo and then filtered with a MW 10,000 centricon (Vivascience, Germany). The active fractions were concentrated and applied to mono-Q ion exchange column chromatography (Pharmacia, Sweden) for further purification of active compound. Finally, the purity of active compound was confirmed by 12% SDS-polyacrylamide gel electrophoresis (FIG. 5). The solvent extraction experiment showed that the active compound was not extracted by the treatment of nonpolar solvents such as hexane, chloroform, ethylacetate and n-butanol, suggesting that the active principle would not be a low molecular weight chemical (data not shown). Accordingly, the broth was washed with equal volume of n-butanol to remove the nonpolar, low molecular weight compounds and the water-soluble fraction was used for further purification. Among the batch-wise eluted fractions of Diaion HP-20 column chromatography, 70% methanol fractions showed the activity. Interestingly, heat-treatment of the fraction for 10 min at 80° C. completely abolished the activity, suggesting that the active compound would be a protein or a peptide (FIG. 4). From MALDI-TOE mass analysis of 70% methanol fractions, the present inventors confirmed that the active compound of KK565 was a protein. To verify the result again, electrophoresis was performed to separate bands. Then, amino acid of N-terminal of the band was examined, resulting in the confirmation that the active compound of the strain was a protein. The 70% methanol fractions were concentrated and further separated with Centricon (MW 10,000) to cut off the residual low molecular weight compounds. The active fraction having more than molecular weight 10,000 was purified with mono-Q column and the fractions were separated under SDS-polyacrylamide gel electrophoresis. As a result, an active compound was separated as a major band (referred as band ‘A’ hereinafter) with molecular weight approximately 30 kDa together with a weak band (referred as band ‘B’ hereinafter) having over 30 kDa molecular weight (approximately 45-50 kDa) (FIG. 5). The band ‘A’ was extracted to analyze sequence of terminal region of amino group. As a result, it seemed to be a peptide represented by SEQ. ID. No 5 and SEQ. ID. No 7. Among nucleotide sequences that are coding amino acid sequences represented by SEQ. ID. No 5 and No 7, degenerative DNA sequences represented by SEQ. ID. No 6 and No 8 were selected based on the frequency of codon utility for PCR. Degenerative DNA sequences were drawn, followed by PCR. Particularly, a nucleotide sequence coding a peptide sequence composed of 7 amino acids that were confirmed by sequence analysis of N-terminal amino acid of a separated/purified protein was put in a database, followed by NCBI blast searching. As a result, it was confirmed that the proteins coded by the above nucleotide sequence were corresponding to Streptomyces griseus aminopeptidase (SGAP; see SEQ. ID. No 10; Spungin, A. and Blumgerg, S., Eur. J. Biochem., 183, 471-477 (1989)) and S. coelicobr putative aminopeptidase (SCPAP; see SEQ. ID. No 11). Amino acid sequences of AABA protein of the present invention and the two proteins confirmed by the above examination were aligned to compare amino acid sequences, resulting in the confirmation that two amino acid sequences represented by SEQ. ID. No 5 and No 7 were common. Finally, degenerative sequences (SEQ. ID. No 6 and No 8) coding the two common amino acid sequences were prepared, which would be used as primers for PCR. IPCR was performed again by using the PCR product as a primer. Particularly, PCR was performed by using amino acid sequences represented by SEQ. ID. No 6 and No 8 as primers as follows; predenaturation at 95° C. for 3 minutes, denaturation at 95° C. for 20 seconds, annealing at 60° C. for 40 minutes, polymerization at 68° C. for 5 minutes, 30 cycles from denaturation to polymerization, and final extension at 72° C. for 10 minutes. “IPCR (inverse PCR)” is a gene amplification technique that amplifies a DNA region close to the well-informed sequences of genomic DNA, which takes advantage of circular DNA changed from a genomic DNA fragment of KK565 strain. Particularly, genomic DNA of KK565 was digested with BamHI, EcOR1, and TaqI, followed by PCR with samples obtained from self-ligation by using a primer prepared from the amplified template DNA fragments, which were also obtained by PCR, to identify nucleotide sequence of a sample DNA. IPCR was then performed with the resultant sequence, amplified by PCR above, using a proper primer, which was repeated to amplify whole sequence of a gene coding AABA protein in order to confirm both initiation codon and termination codon of AABA protein. Genes of AABA protein were cloned from the whole sequence disclosed above and the nucleotide sequences were identified. As a result, it was confirmed that a gene coding AABA protein of the present invention had a nucleotide sequence represented by SEQ. ID. No 4. From the analysis of base sequences of the gene, the present inventors also confirmed that an active protein of the invention had an amino acid sequence represented by SEQ. ID. No 3 comprising 437 amino acids (protein of band B). Further, a protein corresponding to band A was proved to be a fragment of a protein corresponding to band B. The amino acid sequence represented by SEQ. ID. No 3 was compared with any other listed in NCBI database by blast search. As a result, it had 87% homology with Streptomyces griseus sp. aminopeptidase. Therefore, the active protein of the present invention is a novel protein whose amino acid sequence and its DNA sequence were not listed in NCBI database, yet. INDUSTRIAL APPLICABILITY As explained hereinbefore, a protein inhibiting Aβ aggregation, which is separated from Streptomyces sp. KK565, can be effectively used for the prevention and the treatment of neurodegenerative disorders including Alzheimer's disease. In addition, the protein can be a good tool for identifying homologues in mammals and the study of biochemical and cytological functions of the protein enables explaining the molecular mechanism of Aβ accumulation in brain. Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present invention. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims.
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<SOH> BACKGROUND <EOH>Alzheimer's disease (referred as “AD” hereinafter) is a debilitating neurodegenerative disorder in the elederly effecting millions of individuals throughout the world. One of the pathological hallmarks of AD is the extracellular protein deposits referred as senile plaques (Geula, C. et al., Nat. Med., 4, 827-831 (1998)) that consist predominantly of an aggregated peptide known as β amyloid (referred as “Aβ” hereinafter). Aβ, 39-43 amino acid peptides, is produced through proteolytic processing of the β amyloid precursor protein (referred as “βAPP” hereinafter) by β-secretase and γ-secretase (Glenner, G. G. et al., Biochim. Biophys. Res. Commun., 120, 885-890 (1984); Yasojima, K. et al., Neurosci. Lett., 12, 97-100 (2001)). This peptide is particularly amyloidogenic and appears to form the core of the neuritic plaques. The number of plaques appears to correlate with the degree or severity of the dementia (Hasse, C. et al., Cell, 75, 1039-1042 (1993); Selkoe, D. J., J. Neuropathol. Exp. Neurol., 53, 438-447 (1994)). In addition, fibrillar Aβ, amorphous aggregates of Aβ, has been reported to cause neuronal cell death in primary rat hippocampal cultures whereas soluble monomeric species of Aβ are relatively less toxic than fibrillar Aβ (Yankner, B. A. et al., Science, 250, 279-282 (1990)). Other studies suggested that prefibrillar aggregates of Aβ are neurotoxic (Zhu, Y. J. et al., FASEB J., 14, 1244-1254 (2000)). Mutations in genes of either APP or presenilins (PS), which seemed to have a γ-secretase activity, may lead to elevation of the production of Aβ, and are associated with severe and early-onset forms of AD (Yoshiike, Y. et al., J. Biol. Chem., 276, 32293-32299 (2001)). Taken together, Aβ aggregation is considered as a crucial event in the pathogenesis of AD. Accordingly, the efficient inhibition of Aβ aggregation is considered as a powerful way to prevent or treat AD. Therefore, extensive studies have been carried out to discover anti-amyloidogenic compounds from natural or synthetic sources. Several low molecular weight compounds such as antioxidants, free radical scavengers, cholesterol lowering drugs, calcium channel blockers, and γ-secretase inhibitors have been developed as a therapeutic agent for AD (Selkoe, D. J., Physiol. Res., 81, 741-766 (2001)). Among these compounds, γ-secretase inhibitors are known to decrease Aβ production 30-40% (Schroeter, E. H. et al., Nature., 393, 382-386 (1989); Vandermeeren, M. et al., Neurosci Lett., 27, 145-148 (2001)). Among high molecular weight compounds, anti-Aβ antibody, a macromolecular protein, is a good example to enhance clearing of Aβ deposits in transgenic mice that already had begun to develop plaques, possibly by the recruitment of local microglia (Schenk, D. et al., Nature, 400, 173-177 (1999)). Recently, neprilysin which is also known as enkephalinase as well as the common acute lymphoblastic leukemia antigen (CALLA) has been confirmed to be involved in degradation of Aβ-amyloid by its proteolytic activity (Iwata, N. et al., Nat Med., 6, 718-719 (2000); Iwata, N. et al., Science, 292, 1550-1552 (2001)). Moreover, reduced neprilysin level in the plaque area of AD brain was found, suggesting that reduced degradation of Aβ caused by low levels of neprilysin may contribute to AD pathogenesis (Yasojima, K. et al., Neurosci Lett., 12, 97-100 (2001)). In addition, Eckman et al. reported recently that endothelin-converting enzyme-1 (ECE-1) degraded Aβ in vitro at multiple sites (Eckman, E. A. et al., J. Biol. Chem. 27, 24540-24548 (2001)). These results demonstrate that the endogenous concentration of Aβ peptides is regulated not only by its production but also by its catabolism with a specific proteolytic peptidase. Nevertheless, there is something yet to learn about not only high molecular weight compounds inhibiting neurotoxicity caused by Aβ peptide but also a therapeutic agent for neurodegenerative disorders using a high molecular weight biomolecule without side effects by low molecular weight. Thus, the present inventors separated a Streptomyces sp. strain as a target strain producing an active protein inhibiting the aggregation of Aβ peptide inducing AD, and completed this invention by verifying that a protein separated from the strain could be used as a therapeutic agent for neurodegenerative disorders.
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<SOH> SUMMARY OF THE INVENTION <EOH>It is an object of this invention to provide a novel protein inhibiting β amyloid aggregation, a gene coding the protein, a Streptomyces sp. strain producing the protein and a therapeutic agent for neurodegenerative disorders containing the protein as an effective ingredient.
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20040702
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20060926
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20050113
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98145.0
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DESAI, ANAND U
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PROTEIN INHIBITING AGGREGATION OF BETA AMYLOID PEPTIDE
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SMALL
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ACCEPTED
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10,884,808
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ACCEPTED
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Very large dataset representation system and method
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A system and method for representing a very large dataset that enables a plan manager to define, based upon an organization modelling object, a delegation modelling object for a very large dataset. A very large dataset delegation of multiple subplans is created whose subplans can then be individually filtered for specific size restrictions. This enables a plan manager to filter the definition of each subplan prior to the execution of the delegation modelling object, precluding any need for higher-level subplans to contain all the data contained in their subordinate subplans. This allows subplans to contain increased levels of detail not included in their superior subplans, detail that will instead only be summarized in higher-level subplans. A subsequent consolidation process will then extract data not found at higher levels from each delegated subplan, and return that data to its original dataset.
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1. A very large dataset representation system comprising: a delegation modelling object including: a master dataset definition; one or more than one data dimension-to-user mapping; a target organization definition defining relationships between said master dataset definition and said data dimension-to-user mappings; and a subplan definition derived from each data dimension-to-user mapping; and a subplan manager for filtering data from said subplan definitions in accordance with a predetermined data size limitation in advance of executing said delegation modelling object. 2. The system according to claim 1, wherein said data dimension-to-user mappings are described by an organization hierarchy description. 3. The system according to claim 2, wherein said organizational hierarchy description is provided by an organization modelling object having: one or more than one data dimension reference; one or more than one user identifier defining intended recipients; and a mapping between each data dimension reference and one or more than one user identifier. 4. The system according to claim 1, further including a consolidator for, upon completion of user interaction, extracting data from each delegated subplan not found in its superior subplans and returning that extracted data to its original dataset. 5. The system according to claim 1, further including a background server process to improve performance when generating a large number of datasource-based subplans. 6. The system according to claim 1, wherein one or more of said subplan definitions is a proposal to aid in a planning process. 7. A method of representing very large datasets, comprising the steps of: (i) constructing a delegation modelling object by: a) defining a master dataset; b) mapping each data dimension to one or more than one user identifier; c) defining relationships between said master dataset and said data dimension-to-user mappings; and d) deriving a subplan definition from each data dimension-to-user mapping; (ii) filtering data from said subplan definitions in accordance with a predetermined data size limitation in advance of executing said delegation modelling object; and (iii) executing said delegation modelling object to extract and generate subplans. 8. The method according to claim 7, wherein said mapping step is described by the step of providing an organization hierarchy description. 9. The method according to claim 8, wherein said organization hierarchy description is provided by the step of constructing an organization modelling object by: referencing one or more than one data dimension; defining intended recipients with one or more than one user identifier; and mapping each data dimension reference to one or more than one user identifier. 10. The method according to claim 7, further including the step of consolidating data from said delegated subplans upon completion of user interaction. 11. The method according to claim 10, wherein said consolidation step includes the steps of: extracting data from each delegated subplan not found in its superior subplans; and returning said extracted data to its original dataset. 12. The method according to claim 7, further including the step of including a background server process to improve performance when generating a large number of datasource-based subplans. 13. A computer program product for a very large dataset representation method, the computer program product comprising: a computer readable medium for storing machine-executable instructions for use in the execution in a computer of the very large dataset representation method, the method including the steps of: constructing a delegation modelling object by: defining a master dataset; mapping each data dimension to one or more than one user identifier; defining relationships between said master dataset and said data dimension-to-user mappings; and deriving a subplan definition from each data dimension-to-user mapping; filtering data from said subplan definitions in accordance with a predetermined data size limitation in advance of executing said delegation modelling object; and executing said delegation modelling object to extract and generate subplans.
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FIELD OF THE INVENTION The present invention relates generally to electronic databases, and more particularly to the dimensional modelling of a very large dataset. BACKGROUND OF THE INVENTION With advances in contemporary business information systems, all levels of an organization can now enjoy access to repositories of business data known as data warehouses. Data warehousing techniques enable businesses to eliminate extensive amounts of unnecessary workload generated by multiple redundant reporting tasks, and can further facilitate the standardization of data throughout an organization. Business planning applications such as budgeting and forecasting systems are increasingly being integrated into advanced data warehousing solutions in order to maximize returns on what has often been considerable investments in both computing facilities and the gatherings of data they contain. A data warehouse contains collections of related data known as datasets. When these datasets are relatively small, such as when a data warehouse has been recently implemented, users can easily access and work with complete datasets directly on their personal computer systems. However, difficulties arise when datasets get larger. Datasets can eventually grow within a data warehouse facility to contain billions upon billions of individual data values, many times larger than can be handled by the computational capacity of any single user's computer system. In order to provide a workable solution for handling these very large datasets, prior art methods have been employed to extract and deliver subsets of these larger datasets to designated users. This has required close management of the size of each data subset to ensure that users receiving these data subsets can consistently access them given the computational limitations of their individual computer systems, limitations such as calculation size limits, fixed memory limitations, and other hard limits. Upon completion of user interaction in these prior art methods, all data subsets must be returned to their “superior” datasets within the data warehouse through a process known as consolidation. The problem with these prior art methods has been that they employ manual techniques or scripts that must be manually run and maintained in order to extract the data subsets. The consolidation process has also been a mostly manual process of running database-specific scripts. In addition, the administrator responsible for creating and executing the extraction scripts must also keep track of what data has been delivered to which user. The result has been that prior art data warehouse extraction and consolidation methods are highly time-consuming to define, execute and maintain for very large datasets. Furthermore, the delivery of data subsets to designated users lacks integrated tracking, and is often independent of, and therefore outside the control of the organizational security structure employed by the querying application. Therefore, what is needed is a more manageable data model for supporting very large datasets. For the foregoing reasons, there is a need for an improved modelling system and method for handling data queries that generate very large datasets. SUMMARY OF THE INVENTION The present invention is directed to a very large dataset representation system and method. The system includes a delegation modelling object and a subplan manager for filtering data from subplan definitions in accordance with a predetermined data size limitation in advance of executing the delegation modelling object. The delegation modelling object includes a master dataset definition, one or more than one data dimension-to-user mapping, a target organization definition defining relationships between the master dataset definition and the data dimension-to-user mappings, and a subplan definition derived from each data dimension-to-user mapping. In an aspect of the present invention, the system further includes an organizational hierarchy description of the data dimension-to-user mappings provided by an organization modelling object having one or more than one data dimension reference, one or more than one user identifier defining intended recipients, and a mapping between each data dimension reference and one or more than one user identifier. In an aspect of the present invention, the system further includes a consolidator for, upon completion of user interaction, extracting data from each delegated subplan not found in its superior subplans and returning that extracted data to its original dataset. The method includes the steps of constructing a delegation modelling object, filtering data from subplan definitions in accordance with a predetermined data size limitation in advance of executing the delegation modelling object, and executing the delegation modelling object to extract and generate subplans. The delegation modelling object is constructed by defining a master dataset, mapping each data dimension to one or more than one user identifier, defining relationships between the master dataset and the data dimension-to-user mappings, and deriving a subplan definition from each data dimension-to-user mapping. In an aspect of the present invention, the method further includes the step of describing an organization hierarchy of the data dimension-to-user mappings by constructing an organization modelling object through referencing one or more than one data dimension, defining intended recipients with one or more than one user identifier, and mapping each data dimension reference to one or more than one user identifier. In an aspect of the present invention, the method further includes the step of consolidating data from the delegated subplans upon completion of user interaction by extracting data from each delegated subplan not found in its superior subplans, and returning the extracted data to its original dataset. The system provides the ability to delegate from data sources directly, and to directly create data source plans, thereby providing a manageable solution for queries that generate very large datasets, datasets that have heretofore proved difficult to manage. The system further enables a plan manager to update and maintain a data warehouse application in a consistent manner. By providing a highly scalable system of subplans, each within the computational limits of existing computer systems but that are in combination capable of representing a planning problem of virtually any size, the system enables the smooth extraction, management, and consolidation of very large datasets. Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: FIG. 1 is an overview of a very large dataset representation system in accordance with an embodiment of the present invention; FIG. 2 shows the system including an organization modelling object; FIG. 3 shows the system including an organization modelling object, consolidator, and background server process; FIG. 4 is an overview of a very large dataset representation method in accordance with an embodiment of the present invention; FIG. 5 shows the method including the step of constructing an organization modelling object; FIG. 6 shows the method including the step of constructing an organization modelling object, providing a background server process, and consolidating data from delegated subplans; FIG. 7 illustrates region dimensions; FIG. 8 illustrates an organization modelling object with defined associations; FIG. 9 illustrates subplan definitions for an organization modelling object; FIG. 10 illustrates a budget plan; and FIG. 11 illustrates the filtering of subplans in a subplan manager. DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT Embodiments of the present invention are directed to a very large dataset representation system 10 and method 100. As illustrated in FIG. 1, the system 10 includes a delegation modelling object 12 and a subplan manager 14 for filtering data from subplan definitions 22 in accordance with a predetermined data size limitation in advance of executing the delegation modelling object 12. The delegation modelling object 12 includes a master dataset definition 16, one or more than one data dimension-to-user mapping 18, a target organization definition 20 defining relationships between the master dataset definition 16 and the data dimension-to-user mappings 18, and a subplan definition 22 derived from each data dimension-to-user mapping 18. In an embodiment of the present invention, the data dimension-to-user mappings 18 are provided by an organization modelling object 24 having one or more than one data dimension reference 26, one or more than one user identifier 28 defining intended recipients, and a mapping between each data dimension reference and one or more than one user identifier 18, as illustrated in FIG. 2. In an embodiment of the present invention, the system 10 further includes a consolidator 30 for, upon completion of user interaction, extracting data from each delegated subplan 22a not found in its superior subplans 22a and returning that extracted data to its original dataset, as illustrated in FIG. 3. As illustrated in FIG. 4, the method 100 includes the steps of constructing a delegation modelling object 102, filtering data from subplan definitions in accordance with a predetermined data size limitation in advance of executing the delegation modelling object 104, and executing the delegation modelling object to extract and generate subplans 106. The delegation modelling object is constructed by defining a master dataset 108, mapping each data dimension to one or more than one user identifier 110, defining relationships between the master dataset and the data dimension-to-user mappings 112, and deriving a subplan definition from each data dimension-to-user mapping 114. In an embodiment of the present invention, the step of mapping each data dimension to one or more user identifiers 110 is provided by the step of constructing an organization modelling object 116 by referencing one or more than one data dimension 118, defining intended recipients with one or more than one user identifier 120, and mapping each data dimension reference to one or more than one user identifier 122, as illustrated in FIG. 5. In an embodiment of the present invention, the method 100 further includes the step of consolidating data from the delegated subplans upon completion of user interaction 124 by extracting data from each delegated subplan not found in its superior subplans 126, and returning the extracted data to its original dataset 128, as illustrated in FIG. 6. However, before further description of detailed embodiments of the present invention is provided and explained, the following glossary of terms is provided in order to aid in understanding the various elements associated with the present invention. GLOSSARY A “cube” as defined herein is a data-modelling object created either manually or automatically from data sources by a planning modeller. The term cube is often used in the art to describe, in a tangible manner, a conceptual understanding of multi-dimensional data structures, whereby data values can be perceived as being stored in the cells of a multi-dimensional array. A “plan” as defined herein is a guide to providing a “snapshot” of a cube and is created by a database modeller and delivered to the manager of a plan. Unlike cubes, plan dimensions are not modifiable by users. By intention, only plan owners or managers can modify plans. A “subplan” 22a as defined herein is a read-only portion of a plan distributed to user classes based upon a specified organization. Subplans 22a are generated by a delegation process that will be defined below. A “proposal” 36 as defined herein is a modifiable version of a subplan definition 22 created by a subplan owner to aid in a planning process. An “organization” 24 as defined herein is a first-class business-modelling object that defines the relationship between dimensional data and user/role identifiers as defined by a business application's security model. An organization modelling object 24 defines the contents of each in a series of subplans and their hierarchical relationship to one another, defines the contents of each subset of data to be extracted, and associates each data subset with a user who will receive and manage that data subset. Organizations and their embodiment in organization modelling objects 24 are the subject of the Applicant's co-pending United States application for patent titled “Organization Modelling Object as a First-Class Business Modelling Object, and Method and System for Providing Same” filed Feb. 19, 2003, the teachings of which are hereby incorporated by reference in their entirety. A “delegation” 12 as defined herein is a first-class business-modelling object that associates a dataset with an organization modelling object 24, and manages the workflow and scheduling around the delivery of subsets of data. Delegation modelling objects 12 provide a formal definition of this process by defining a master dataset and associating the organization hierarchy by which specific datasets or subplans 22a will be generated from the master dataset. A delegation modelling object 12 automates the creation and delivery of subplans 22a and keeps track of changes to subplans 22a over time. A delegation modelling object 12 also provides control to shutdown, as well as clean up an entire delegation process. Delegation modelling objects 12 are described in detail in Applicant's co-pending United States application for patent, titled “Delegation Modelling Object as a First-Class Business Modelling Object, and Method and System for Providing Same” filed Feb. 19, 2003, the teachings of which are hereby incorporated by reference in their entirety. A “dataset” as defined herein is a set of related source data to be used by a delegation modelling object 12 in data extraction and consolidation processes. A dataset should therefore contain elements of the dimensionality referenced in an organization modelling object 24. Furthermore, a single dataset can be the source of more than one distinct delegation 12. “Subplan filtering” as defined herein describes a process by which each subplan definition 22 is filtered for distribution down to a maximum data size, while respecting the hierarchy as defined by its organization modelling object 24 in order that each user can work with that data on their individual computer systems. “Consolidation” as defined herein describes a process for the reintegration of all data subsets 22a back into their original dataset. Returning now to a detailed description of the present invention, the delegation of a very large dataset is a process by which the extractions of data from a data warehouse are described by an organization 24, and managed by a delegation 12. Very large dataset delegations 12 are reusable definitions that provide data extraction methods based on business organizational rules, workflow management, and subplan filtering while respecting the organizational integrity defined by the organization 24, as well as consolidation back into an original dataset. A delegation modelling object 12 contains a reference to an organization modelling object 24 in order to define how a master dataset is to be broken out and delivered. A delegation 12 provides a relationship between dimensional data and management roles provided by a data dimension-to-user mapping 18 in order to establish areas of responsibility. As opposed to a very large dataset delegation 12 in accordance with the present invention, in a “regular” delegation as embodied and described in Applicant's aforementioned co-pending United States application for patent titled “Delegation Modelling Object as a First-Class Business Modelling Object, and Method and System for Providing Same” each generated subset of data represents the subplan 22a of a larger data subplan 22a generated at a higher level of a management hierarchy. The hierarchy of those subplans 22a is defined in an organization modelling object 24, and since the top-level plan in a so-called “regular” delegation contains the entire dataset, no consolidation back to the original dataset is required. Therefore, in a planning area consolidation process for example, each subplan 22a delegated to a user will roll back up the chain of delegated subplans 22a to a “top-level” plan. However, since each higher-level or “superior” subplan 22a will contain all the data from each of its subordinate subplans 22a, higher-level subplans 22a will become increasingly large, with high-level subplans 22a in larger organizations ultimately becoming unmanageable. The very large dataset representation system 10 enables a plan manager to define, based upon an organization modelling object 24, a delegation modelling object 12 for a very large dataset. This creates a very large dataset delegation 12 of multiple subplans 22a that can then be individually filtered for specific size restrictions. The system 10 enables a plan manager to filter the definition 22 of each subplan prior to the execution of the delegation modelling object 12 precluding any need for higher-level subplans 22a to contain all the data contained in their subordinate subplans 22a. This allows subplans 22a to contain increased levels of detail not included in their superior subplans 22a, detail that will instead only be summarized in higher-level subplans 22a. A subsequent consolidator 30 process will then extract data not found at higher levels from each delegated subplan 22a, and return that data to its original dataset. Much like the previously defined regular delegation modelling object that binds a dataset to an organization modelling object 24 in order to define a set of related data subsets, the very large dataset representation system 10 associates or “maps” an organization's 24 hierarchal structure to an external source of data such as a data warehouse in order to define a set of related subplans 22a. When a very large dataset delegation 12 is run, data is extracted directly from an external source and delivered to the computer systems of individual users, with each subplan 22a generated on an individual basis having been filtered in accordance with data size limits. An exemplary example of the use of an embodiment of the very large dataset representation system 10 is illustrated in the following discussion and accompanying figures. In this example, ABC Co. has a budget-related dataset in its data warehouse that it wishes to distribute to each of ABC Co.'s regional managers. This budget dataset contains a master dimension 26 that includes the category dimensions 26 “Account Measures” “Territories” “Vendor Segments” and “Years”. As illustrated in FIG. 7, in addition to the category dimensions 26 the budget dataset further contains the region dimensions 26, “United States”, “Brazil” and “Canada” all subordinated to an “Americas” region dimension 26. The budget dataset also contains a measures dimension 26 as illustrated in TABLE 1. TABLE 1 Measures Dimension Revenue Net Income Gross Margin Gross Profit Break Even Net Margin Return on Assets Current Ratio Debt/Asset Cost of Goods Sold Operating Cost Total Operating Expenses As well, ABC Co. has defined the management roles 28 illustrated in TABLE 2. TABLE 2 Management Roles District 1 Manager Responsible for all of the “Americas” regions District 2 Manager Responsible for the United States” region, and reporting to “District 1” manager District 3 Manager Responsible for the “Brazil” region, and reporting to “District 1” manager District 4 Manager Responsible for the “Canada” region, and reporting to “District 1” manager Therefore as illustrated in FIG. 8, a budget manager for ABC Co. would advantageously create a new organization modelling object 24 that would better define these associations. This newly created organization modelling object 24 defines the four subplan definitions 22 illustrated in FIG. 9. If delegated for a large organization, it can be seen by one of skill in the art that the provided organization modelling object 24 would likely define a hierarchy of subplans 22a that would all easily exceed the maximum subplan 22a data size for each user, based on current computing capacity common in most organizations at the user level. However, the system 10 can be leveraged to distribute and subsequently consolidate the ABC Co. budget. In accordance with an embodiment of the very large dataset representation system 10, the “Budget Plan” illustrated in FIG. 10 has been pre-filtered to contain only a summary of each region. If executed, the subplan definitions 22 shown with “not available” icons 32 would all have exceeded the maximum subplan 22a data size. However, using the subplan manager 14 to filter each subplan definition 22 prior to executing the delegation 12 in accordance with the system 10, a plan manager is able to define a “deliverable” subplan 22a for each user. Thus, the use of a very large dataset in combination with the delegation process has allowed the plan manager to create an organization modelling object 24 based on the region dimension 26, and subsequently assign different region members 26 to each district user class 28, or area of responsibility. The plan manager is then able to create a delegation modelling object 12 for that budget plan, and using the subplan manager 14 edit each subplan definition 22 in that delegation modelling object 12 by selecting only those measures they feel necessary in order to meet the size restrictions of a particular application, as illustrated in FIG. 11. The delegation modelling object 12 is then executed in order to extract and generate deliverable subplans 22a to each designated user. While the budget plan continues to contain a summary of the regions and all of the measures and each subplan 22a continues to contain all of its specific region members 26, only a subset of the measures data is actually provided to each user. Therefore, all generated subplans 22a in the executed delegation 12 is now less than the pre-determined maximum subplan 22a data size. A subsequent consolidation process 30 then reintegrates all data subsets 22a directly back into their original source dataset. Each data subset 22a generated by a very large dataset delegation 12 is a part of that delegation's workflow. Modified subplans 22a are returned “up” an organization's management chain, where managers can then accept or reject subordinate subplans 22a returned to them by subordinate users 28. The management workflow process then culminates in the reconstitution of all accepted subplans 22a back into their original dataset. Data from each subplan 22a not found in its respective higher level or “superior” subplan 22a is extracted and consolidated directly back into the original source dataset. In this manner, the manager of a plan can have firm control over which subplans 22a will, and which subplans 22a will not be used for a specific process. When a very large dataset delegation 12 is run, data is extracted directly from the external data source, and each subplan 22a is subsequently generated directly, and independently of the delegation 12. Subplan definitions 22 can also be updated whenever a data warehouse reporting system is likewise updated. If so desired, the system 10 can be independent of a delegation process 12, enabling a plan manager to initiate an update of a data warehouse reporting system at any point along the process. In an embodiment of the present invention, the system 10 can further include a background server process 34 for improved performance when generating a large number of datasource-based subplans 22a from a plan delegation process 12, as illustrated in FIG. 3. In an embodiment of the present invention, the method 100 can further include the step of providing a background server process 130 for improved performance when generating a large number of datasource-based subplans from a plan delegation process, as illustrated in FIG. 6. The system 10 initiates a process by which very large sets of data, typically those datasets greater than about five million cells, external to a data warehouse solution can be imported into that process as a much more manageable set of related planning data subsets 22a. In addition, the system 10 provides the ability to delegate directly from data sources, and to directly create data source plans, thereby providing a manageable solution for queries that generate very large datasets, datasets that have heretofore proved difficult to manage. The system 10 further enables a plan manager to update and maintain a data warehouse application in a consistent manner. By providing a highly scalable system of subplans 22a, each within the computational limits of existing computer systems, but whose combined structure is capable of representing a planning problem of virtually any size, the system 10 enables the smooth extraction, management, and consolidation of very large datasets. Any hardware, software or a combination of hardware and software having the above-described functions may implement the very large dataset representation system 10 and method 100 according to the present invention, and methods described above. The software code, either in its entirety or a part thereof, may be in the form of a computer program product such as a computer-readable memory having the model and/or method stored therein. Furthermore, a computer data signal representation of that software code may be embedded in a carrier wave for transmission via communications network infrastructure. Such a computer program product and a computer data signal are also within the scope of the present invention, as well as the hardware, software and combination thereof. Therefore, although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein.
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<SOH> BACKGROUND OF THE INVENTION <EOH>With advances in contemporary business information systems, all levels of an organization can now enjoy access to repositories of business data known as data warehouses. Data warehousing techniques enable businesses to eliminate extensive amounts of unnecessary workload generated by multiple redundant reporting tasks, and can further facilitate the standardization of data throughout an organization. Business planning applications such as budgeting and forecasting systems are increasingly being integrated into advanced data warehousing solutions in order to maximize returns on what has often been considerable investments in both computing facilities and the gatherings of data they contain. A data warehouse contains collections of related data known as datasets. When these datasets are relatively small, such as when a data warehouse has been recently implemented, users can easily access and work with complete datasets directly on their personal computer systems. However, difficulties arise when datasets get larger. Datasets can eventually grow within a data warehouse facility to contain billions upon billions of individual data values, many times larger than can be handled by the computational capacity of any single user's computer system. In order to provide a workable solution for handling these very large datasets, prior art methods have been employed to extract and deliver subsets of these larger datasets to designated users. This has required close management of the size of each data subset to ensure that users receiving these data subsets can consistently access them given the computational limitations of their individual computer systems, limitations such as calculation size limits, fixed memory limitations, and other hard limits. Upon completion of user interaction in these prior art methods, all data subsets must be returned to their “superior” datasets within the data warehouse through a process known as consolidation. The problem with these prior art methods has been that they employ manual techniques or scripts that must be manually run and maintained in order to extract the data subsets. The consolidation process has also been a mostly manual process of running database-specific scripts. In addition, the administrator responsible for creating and executing the extraction scripts must also keep track of what data has been delivered to which user. The result has been that prior art data warehouse extraction and consolidation methods are highly time-consuming to define, execute and maintain for very large datasets. Furthermore, the delivery of data subsets to designated users lacks integrated tracking, and is often independent of, and therefore outside the control of the organizational security structure employed by the querying application. Therefore, what is needed is a more manageable data model for supporting very large datasets. For the foregoing reasons, there is a need for an improved modelling system and method for handling data queries that generate very large datasets.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention is directed to a very large dataset representation system and method. The system includes a delegation modelling object and a subplan manager for filtering data from subplan definitions in accordance with a predetermined data size limitation in advance of executing the delegation modelling object. The delegation modelling object includes a master dataset definition, one or more than one data dimension-to-user mapping, a target organization definition defining relationships between the master dataset definition and the data dimension-to-user mappings, and a subplan definition derived from each data dimension-to-user mapping. In an aspect of the present invention, the system further includes an organizational hierarchy description of the data dimension-to-user mappings provided by an organization modelling object having one or more than one data dimension reference, one or more than one user identifier defining intended recipients, and a mapping between each data dimension reference and one or more than one user identifier. In an aspect of the present invention, the system further includes a consolidator for, upon completion of user interaction, extracting data from each delegated subplan not found in its superior subplans and returning that extracted data to its original dataset. The method includes the steps of constructing a delegation modelling object, filtering data from subplan definitions in accordance with a predetermined data size limitation in advance of executing the delegation modelling object, and executing the delegation modelling object to extract and generate subplans. The delegation modelling object is constructed by defining a master dataset, mapping each data dimension to one or more than one user identifier, defining relationships between the master dataset and the data dimension-to-user mappings, and deriving a subplan definition from each data dimension-to-user mapping. In an aspect of the present invention, the method further includes the step of describing an organization hierarchy of the data dimension-to-user mappings by constructing an organization modelling object through referencing one or more than one data dimension, defining intended recipients with one or more than one user identifier, and mapping each data dimension reference to one or more than one user identifier. In an aspect of the present invention, the method further includes the step of consolidating data from the delegated subplans upon completion of user interaction by extracting data from each delegated subplan not found in its superior subplans, and returning the extracted data to its original dataset. The system provides the ability to delegate from data sources directly, and to directly create data source plans, thereby providing a manageable solution for queries that generate very large datasets, datasets that have heretofore proved difficult to manage. The system further enables a plan manager to update and maintain a data warehouse application in a consistent manner. By providing a highly scalable system of subplans, each within the computational limits of existing computer systems but that are in combination capable of representing a planning problem of virtually any size, the system enables the smooth extraction, management, and consolidation of very large datasets. Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
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20040702
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20080219
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20060105
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70246.0
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G06F1700
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LY, ANH
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VERY LARGE DATASET REPRESENTATION SYSTEM AND METHOD
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UNDISCOUNTED
| 0
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ACCEPTED
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G06F
| 2,004
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10,884,830
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ACCEPTED
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Human antibodies that bind human IL-12 and methods for producing
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Human antibodies, preferably recombinant human antibodies, that specifically bind to human interleukin-12 (hIL-12) are disclosed. Preferred antibodies have high affinity for hIL-12 and neutralize hIL-12 activity in vitro and in vivo. An antibody of the invention can be a full-length antibody or an antigen-binding portion thereof. The antibodies, or antibody portions, of the invention are useful for detecting hIL-12 and for inhibiting hIL-12 activity, e.g., in a human subject suffering from a disorder in which hIL-12 activity is detrimental. Nucleic acids, vectors and host cells for expressing the recombinant human antibodies of the invention, and methods of synthesizing the recombinant human antibodies, are also encompassed by the invention.
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1. An isolated human antibody, or an antigen-binding portion thereof, that binds to human IL-12, wherein said human antibody is a neutralizing antibody. 2. A selectively mutated human IL-12 antibody, comprising: a human antibody or antigen-binding portion thereof, selectively mutated at a preferred selective mutagenesis, contact or hypermutation position with an activity enhancing amino acid residue such that it binds to human IL-12. 3. A selectively mutated human IL-12 antibody, comprising: a human antibody or antigen-binding portion thereof, selectively mutated at a preferred selective mutagenesis position with an activity enhancing amino acid residue such that it binds to human IL-12. 4. The selectively mutated human IL-12 antibody of claim 2, wherein the human antibody or antigen-binding portion thereof is selectively mutated at more than one preferred selective mutagenesis, contact or hypermutation positions with an activity enhancing amino acid residue. 5. The selectively mutated human IL-12 antibody of claim 4, wherein the human antibody or antigen-binding portion thereof is selectively mutated at no more than three preferred selective mutagenesis, contact or hypermutation positions. 6. The selectively mutated human IL-12 antibody of claim 4, wherein the human antibody or antigen-binding portion thereof is selectively mutated at no more than two preferred selective mutagenesis, contact or hypermutation positions. 7. The selectively mutated human IL-12 antibody of claim 2, wherein the human antibody or antigen-binding portion thereof, is selectively mutated such that a target specificity affinity level is attained, said target level being improved over that attainable when selecting for an antibody against the same antigen using phage display technology. 8. The selectively mutated human IL-12 antibody of claim 7, wherein the selectively mutated human antibody further retains at least one desirable property or characteristic. 9. An isolated human antibody, or antigen-binding portion thereof, that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. 10. The isolated human antibody of claim 9, or an antigen-binding portion thereof, which dissociates from human IL-12 with a koff rate constant of 1×10−2s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−7M or less. 11. The isolated human antibody of claim 9, or an antigen-binding portion thereof, which dissociates from human IL-12 with a koff rate constant of 1×10−3s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−8M or less. 12. The isolated human antibody of claim 9, or an antigen-binding portion thereof, which dissociates from human IL-12 with a koff rate constant of 1×10−4s- or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less. 13. The isolated human antibody of claim 9, or an antigen-binding portion thereof, which dissociates from human IL-12 with a koff rate constant of 1×10−5s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−11M or less. 14. The isolated human antibody of claim 9, or an antigen-binding portion thereof, which dissociates from human IL-12 with a koff rate constant of 1×10−5 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−11M or less. 15. An isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−6M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2. 16. The isolated human antibody of claim 15, or an antigen-binding portion thereof, which further has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3; and has a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4. 17. The isolated human antibody of claim 15, or an antigen-binding portion thereof, which further has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and has a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. 18. The isolated human antibody, or antigen binding portion thereof of claim 16, which has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 7; and has a light chain variable region comprising the amino acid sequence of SEQ ID NO: 8. 19. An isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10. 20. The isolated human antibody of claim 19, or an antigen-binding portion thereof, which further has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11; and has a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12. 21. The isolated human antibody of claim 19, or an antigen-binding portion thereof, which further has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and has a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. 22. The isolated human antibody of claim 19, which has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 15; and has a light chain variable region comprising the amino acid sequence of SEQ ID NO: 16. 23. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. 24. The isolated human antibody, or an antigen-binding portion thereof, of claim 23 which further has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19; and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20. 25. The isolated human antibody, or an antigen-binding portion thereof, of claim 23 which further has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. 26. An isolated human antibody, or an antigen-binding portion thereof, having a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. 27. The isolated human antibody of claim 26, comprising a heavy chain constant region selected from the group consisting of IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions. 28. The isolated human antibody of claim 27, wherein the antibody heavy chain constant region is IgG1. 29. The isolated human antibody of claim 26, which is a Fab fragment. 30. The isolated human antibody of claim 26, which is a F(ab′)2 fragment. 31. The isolated human antibody of claim 26, which is a single chain Fv fragment. 32. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less; b) has a heavy chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 404-SEQ ID NO: 469; or c) has a light chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 534-SEQ ID NO: 579. 33. The isolated human antibody, or an antigen-binding portion thereof, of claim 32 which further has a heavy chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO:335-SEQ ID NO: 403; or a light chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 506-SEQ ID NO: 533. 34. The isolated human antibody, or an antigen-binding portion thereof, of claim 32 which further has a heavy chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 288-SEQ ID NO: 334; or a light chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 470-SEQ ID NO: 505. 35. An isolated human antibody, or an antigen-binding portion thereof, having a the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. 36. The isolated human antibody of claim 35, comprising a heavy chain constant region selected from the group consisting of IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions. 37. The isolated human antibody of claim 36, wherein the antibody heavy chain constant region is IgG1. 38. The isolated human antibody of claim 35, which is a Fab fragment. 39. The isolated human antibody of claim 35, which is a F(ab′)2 fragment. 40. The isolated human antibody of claim 35, which is a single chain Fv fragment. 41. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. 42. The isolated human antibody, or an antigen-binding portion thereof, of claim 41 which further has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28. 43. The isolated human antibody, or an antigen-binding portion thereof, of claim 41 which further has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. 44. An isolated human antibody, or an antigen-binding portion thereof, having a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 32. 45. The isolated human antibody of claim 44, comprising a heavy chain constant region selected from the group consisting of IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions. 46. The isolated human antibody of claim 45, wherein the antibody heavy chain constant region is IgG1. 47. The isolated human antibody of claim 44, which is a Fab fragment. 48. The isolated human antibody of claim 44, which is a F(ab′)2 fragment. 49. The isolated human antibody of claim 44, which is a single chain Fv fragment. 50. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−6M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a kff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. 51. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a Koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. 52. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an 1C50 of 1×10−9M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. 53. An isolated nucleic acid encoding the heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17. 54. The isolated nucleic acid of claim 53, which encodes an antibody heavy chain variable region. 55. The isolated nucleic acid of claim 54, wherein the CDR2 of the antibody heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 19. 56. The isolated nucleic acid of claim 54, wherein the CDR1 of the antibody heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 21. 57. The isolated nucleic acid of claim 56, which encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23. 58. An isolated nucleic acid encoding the light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. 59. The isolated nucleic acid of claim 58, which encodes an antibody light chain variable region. 60. The isolated nucleic acid of claim 59, wherein the CDR2 of the antibody light chain variable region comprises the amino acid sequence of SEQ ID NO: 20. 61. The isolated nucleic acid of claim 59, wherein the CDR1 of the antibody light chain variable region comprises the amino acid sequence of SEQ ID NO: 22. 62. The isolated nucleic acid of claim 61, which encodes an antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. 63. An isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a off rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. 64. An isolated nucleic acid encoding the heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25. 65. The isolated nucleic acid of claim 64, which encodes an antibody heavy chain variable region. 66. The isolated nucleic acid of claim 65, wherein the CDR2 of the antibody heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 27. 67. The isolated nucleic acid of claim 65, wherein the CDR 1 of the antibody heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 29. 68. The isolated nucleic acid of claim 67, which encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31. 69. An isolated nucleic acid encoding the light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. 70. The isolated nucleic acid of claim 69, which encodes an antibody light chain variable region. 71. The isolated nucleic acid of claim 70, wherein the CDR2 of the antibody light chain variable region comprises the amino acid sequence of SEQ ID NO: 28. 72. The isolated nucleic acid of claim 70, wherein the CDR1 of the antibody light chain variable region comprises the amino acid sequence of SEQ ID NO: 30. 73. The isolated nucleic acid of claim 72, which encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 32. 74. An isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the VH3 germline family, wherein the heavy chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from a member of the VX 1 germline family, wherein the light chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. 75. An isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-] 2 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 595-667, wherein the heavy chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 669-675, wherein the light chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. 76. An isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising the COS-3 germline amino acid sequence, wherein the heavy chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising the DPL8 germline amino acid sequence, wherein the light chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. 77. An isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the VH3 germline family, wherein the heavy chain variable region comprises a CDR2 that is structurally similar to CDR2s from other VH3 germline family members, and a CDR1 that is structurally similar to CDR1 s from other VH3 germline family members, and wherein the heavy chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue; c) has a light chain variable region comprising an amino acid sequence selected from a member of the Vλ1 germline family, wherein the light chain variables region comprises a CDR2 that is structurally similar to CDR2s from other Vλ1 germline family members, and a CDR1 that is structurally similar to CDR1s from other Vλ1 germline family members, and wherein the light chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. 78. The isolated human antibody, or antigen binding portion thereof, of claim 74, wherein the mutation is in the heavy chain CDR3. 79. The isolated human antibody, or antigen binding portion thereof, of claim 74, wherein the mutation is in the light chain CDR3. 80. The isolated human antibody, or antigen binding portion thereof, of claim 74, wherein the mutation is in the heavy chain CDR2. 81. The isolated human antibody, or antigen binding portion thereof, of claim 74, wherein the mutation is in the light chain CDR2. 82. The isolated human antibody, or antigen binding portion thereof, of claim 74, wherein the mutation is in the heavy chain CDR1. 83. The isolated human antibody, or antigen binding portion thereof, of claim 74, wherein the mutation is in the light chain CDR1. 84. A recombinant expression vector encoding: a) an antibody heavy chain having a variable region comprising the amino acid sequence of SEQ ID NO: 31; and b) an antibody light chain having a variable region comprising the amino acid sequence of SEQ ID NO: 32. 85. A host cell into which the recombinant expression vector of claim 84 has been introduced. 86. A method of synthesizing a human antibody that binds human IL-12, comprising culturing the host cell of claim 85 in a culture medium until a human antibody that binds human IL-12 is synthesized by the cell. 87. An isolated human antibody, or antigen-binding portion thereof, that neutralizes the activity of human IL-12, and at least one additional primate IL-12 selected from the group consisting of baboon IL-12, marmoset IL-12, chimpanzee IL-12, cynomolgus IL-12 and rhesus IL-12, but which does not neutralize the activity of the mouse IL-12. 88. A pharmaceutical composition comprising the antibody or an antigen binding portion thereof, of claim 1 and a pharmaceutically acceptable carrier. 89. A composition comprising the antibody or an antigen binding position thereof, of claim land an additional agent. 90. The composition of claim 89, wherein the additional agent is a therapeutic agent. 91. The composition of claim 90, wherein the therapeutic agent is selected from the group consisting of budenoside, epidermal growth factor, corticosteroids, cyclosporin, sulfasalazine, aminosalicylates, 6-mercaptopurine, azathioprine, metronidazole, lipoxygenase inhibitors, mesalamine, olsalazine, balsalazide, antioxidants, thromboxane inhibitors, IL-1 receptor antagonists, anti-IL-1β monoclonal antibodies, anti-IL-6 monoclonal antibodies, growth factors, elastase inhibitors, pyridinyl-imidazole compounds, antibodies or agonists of TNF, LT, IL-1, IL-2, IL-6, IL-7, IL-8, IL-15, IL-16, IL-18, EMAP-II, GM-CSF, FGF, and PDGF, antibodies of CD2, CD3, CD4, CD8, CD25, CD28, CD30, CD40, CD45, CD69, CD90 or their ligands, methotrexate, cyclosporin, FK506, rapamycin, mycophenolate mofetil, leflunomide, NSAIDs, ibuprofen, corticosteroids, prednisolone, phosphodiesterase inhibitors, adenosine agonists, antithrombotic agents, complement inhibitors, adrenergic agents, IRAK, NIK, IKK, p38, MAP kinase inhibitors, IL-1P converting enzyme inhibitors, TNFα converting enzyme inhibitors, T-cell signalling inhibitors, metalloproteinase inhibitors, sulfasalazine, azathioprine, 6-mercaptopurines, angiotensin converting enzyme inhibitors, soluble cytokine receptors, soluble p55 TNF receptor, soluble p75 TNF receptor, sIL-1RI, sIL-1RII, sIL-6R, antiinflammatory cytokines, IL-4, IL-10, IL-11, IL-13 and TGFβ. 92. The therapeutic composition of claim 90, wherein the therapeutic agent is selected from the group consisting of anti-TNF antibodies, and antibody fragments thereof, TNFR-Ig constructs, TACE inhibitors, PDE4 inhibitors, corticosteroids, budenoside, dexamethasone, sulfasalazine, 5-aminosalicylic acid, olsalazine, IL-1β converting enzyme inhibitors, IL-1ra, tyrosine kinase inhibitors, 6-mercaptopurines and IL-11. 93. The therapeutic composition of claim 90, wherein the therapeutic agent is selected from the group consisting of corticosteroids, prednisolone, methylprednisolone, azathioprine, cyclophosphamide, cyclosporine, methotrexate, 4-aminopyridine, tizanidine, interferon-β1a, interferon-β1b, Copolymer 1, hyperbaric oxygen, intravenous immunoglobulin, clabribine, antibodies or agonists of TNF, LT, IL-1, IL-2, IL-6, IL-7, IL-8, IL-15, IL-16, IL-18, EMAP-II, GM-CSF, FGF, PDGF, antibodies to CD2, CD3, CD4, CD8, CD25, CD28, CD30, CD40, CD45, CD69, CD80, CD86, CD90 or their ligands, methotrexate, cyclosporine, FK506, rapamycin, mycophenolate mofetil, leflunomide, NSAIDs, ibuprofen, corticosteroids, prednisolone, phosphodiesterase inhibitors, adensosine agonists, antithrombotic agents, complement inhibitors, adrenergic agents, IRAK, NIK, IKK, p38 or MAP kinase inhibitors, IL-1β converting enzyme inhibitors, TACE inhibitors, T-cell signalling inhibitors, kinase inhibitors, metalloproteinase inhibitors, sulfasalazine, azathioprine, 6-mercaptopurines, angiotensin converting enzyme inhibitors, soluble cytokine receptors, soluble p55 TNF receptor, soluble p75 TNF receptor, sIL-1 RI, sIL-1RII, sIL-6R, sIL-13R, anti-P7s, p-selectin glycoprotein ligand (PSGL), antiinflammatory cytokines, IL-4, IL-10, IL-13 and TGFβ. 94. A method for inhibiting human IL-12 activity comprising contacting human IL-12 with the antibody of claim 44 such that human IL-12 activity is inhibited. 95. A method for inhibiting human IL-12 activity in a human subject suffering from a disorder in which IL-12 activity is detrimental, comprising administering to the human subject the antibody of claim 44 such that human IL-12 activity in the human subject is inhibited. 96. The method of claim 95, wherein the disorder is selected from the group consisting of rheumatoid arthritis, osteoarthritis, juvenile chronic arthritis, Lyme arthritis, psoriatic arthritis, reactive arthritis, spondyoarthropathy, ankylosing spondylitis, systemic lupus erythematosis, Crohn's disease, ulcerative colitis, inflammatory bowel disease, multiple sclerosis, insulin dependent diabetes mellitus, thyroiditis, asthma, allergic diseases, psoriasis, dermatitisscleroderma, thyroiditis, graft versus host disease, organ transplant rejection, acute or chronic immune disease associated with organ transplantation, sarcoidosis, atherosclerosis, disseminated intravascular coagulation, Kawasaki's disease, Grave's disease, nephrotic syndrome, chronic fatigue syndrome, polyarteritis nodosa, Wegener's granulomatosis, Henoch-Schonlein purpura, microscopic vasculitis of the kidneys, chronic active hepatitis, Sjogren's syndrome, uveitis, sepsis, septic shock, sepsis syndrome, adult respiratory, distress syndrome, cachexia, infectious diseases, parasitic diseases, acquired immunodeficiency syndrome, acute transverse myelitis, myasthenia gravis, Huntington's chorea, Parkinson's disease, Alzheimer's disease, stroke, primary biliary cirrhosis, fibrotic lung diseases, hemolytic anemia, malignancies, heart failure and myocardial infarction. 97. The method of claim 95, wherein the disorder is Crohn's disease. 98. The method of claim 95, wherein the disorder is multiple sclerosis. 99. The method of claim 95, wherein the disorder is rheumatoid arthritis. 100. A method for improving the activity of an antibody, or antigen-binding portion thereof, to attain a predetermined target activity, comprising: a) providing a parent antibody a antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position selected from group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. c) individually mutating the selected preferred selective mutagenesis position to at least two other amino acid residues to hereby create a first panel of mutated antibodies, or antigen binding portions thereof; d) evaluating the activity of the first panel of mutated antibodies, or antigen binding portions thereof to determined if mutation of a single selective mutagenesis position produces an antibody or antigen binding portion thereof with the predetermined target activity or a partial target activity; e) combining in a stepwise fashion, in the parent antibody, or antigen binding portion thereof, individual mutations shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof. f) evaluating the activity of the combination antibodies, or antigen binding portions thereof to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity. g) if steps d) or f) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result an antibody with only a partial activity, the method further comprising mutating additional amino acid residues selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 to at least two other amino acid residues to thereby create a second panel of mutated antibodies or antigen-binding portions thereof; h) evaluating the activity of the second panel of mutated antibodies or antigen binding portions thereof, to determined if mutation of a single amino acid residue selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 results an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; i) combining in stepwise fashion in the parent antibody, or antigen-binding portion thereof, individual mutations of step g) shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof; j) evaluating the activity of the combination antibodies or antigen binding portions thereof, to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity; k) if steps h) or j) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result in an antibody with only a partial activity, the method further comprising mutating additional amino acid residues selected from the group consisting of H33B, H52B and L31A to at least two other amino acid residues to thereby create a third panel of mutated antibodies or antigen binding portions thereof; l) evaluating the activity of the third panel of mutated antibodies or antigen binding portions thereof, to determine if a mutation of a single amino acid residue selected from the group consisting of H33B, H52B and L31A resulted in an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; m) combining in a stepwise fashion in the parent antibody, or antigen binding portion thereof, individual mutation of step k) shown to have an improved activity, to form combination antibodies, or antigen binding portions, thereof; n) evaluating the activity of the combination antibodies or antigen-binding portions thereof, to determine if the combination antibodies, or antigen binding portions thereof have the predetermined target activity to thereby produce an antibody or antigen binding portion thereof with a predetermined target activity. 101. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof, b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, e) repeating steps b) through d) for at least one other preferred selective mutagenesis position, contact or hypermutation position if the desired antibody activity is not obtained; f) combining in a stepwise fashion, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof, and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 102. The method of claim 101, wherein contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. 103. The method of claim 101, wherein hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. 104. The method of claim 101, wherein the preferred positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. 105. The method of claim 101, wherein the contact positions are selected from the group consisting of L50 and L94. 106. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity is not further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) repeating steps b) through d) for at least one other preferred selective mutagenesis position, contact or hypermutation position if the desired antibody activity is not obtained; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 107. The method of claim 106, wherein contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. 108. The method of claim 106, wherein hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. 109. The method of claim 106, wherein preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 110. The method of claim 106, wherein the contact positions are selected from the group consisting of L50 and L94. 111. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expressing said panel in an appropriate expression system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained in the antibody; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 112. The method of claim 111, wherein contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 113. The method of claim 111, wherein the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 114. The method of claim 111, wherein the preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93 and L94 and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 115. The method of claim 111, wherein the contact positions are selected from the group consisting of L50 and L94, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 116. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least one retained property or characteristic, to form combination antibodies, or antigen-binding portions thereof, and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 117. The method of claim 116, wherein contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 118. The method of claim 116, wherein the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 119. The method of claim 116 wherein the preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93 and L94, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 120. The method of claim 116, wherein the contact positions are selected from the group consisting of L50 and L94, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 121. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one additional property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic relative to the parent antibody, or antigen-binding portion thereof, is obtained. 122. The method of claim 121, wherein contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 123. The method of claim 121, wherein the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 124. The method of claim 121, wherein the contact positions are selected from the group consisting of L50 and L94, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 125. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least one retained property or characteristic, to form combination antibodies, or antigen-binding portions thereof, and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic relative to the parent antibody, or antigen-binding portion thereof, is obtained. 126. The method of claim 125, wherein contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 127. The method of claim 125, wherein the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 128. The method of claim 125 wherein the preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93 and L94, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 129. The method of claim 125, wherein the contact positions are selected from the group consisting of L50 and L94, and wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-crossreactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 130. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting a amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 131. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting a amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other position within the CDR which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H104, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 132. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof, that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a selecting an amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic, until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 133. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other position within the CDR which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and other property or characteristics of the combination antibodies, or antigen-binding portions thereof, with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 134. A method for improving the activity of an antibody, or antigen-binding portion thereof, without affecting other properties, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic, wherein the property or characteristic needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and retained property, or characteristic relative to the parent antibody, or antigen-binding portion thereof, is obtained. 135. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H152, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies or antigen-binding portions thereof, relative to the parent antibody or antigen-portion thereof, for changes in at least one other property or characteristic; f) repeating steps b) through e) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity but not affecting at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof with at least one retained property or characteristic; and h) evaluating the activity and the retention of at least one property of characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 136. A method to improve the affinity of an antibody or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 137. A method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity and retention of at least one other property or characteristic of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not to affect at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and retention of at least one other property or characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one other retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. 138. The method of claim 130, wherein the other property or characteristic is selected from the group consisting of preservation of non-crossreactivity with other proteins, preservation of non-cross reactivity with other human tissues, preservation of epitope recognition and an antibody with a close to germline immunoglobulin sequence. 139. A method for detecting human IL-12 comprising contacting human IL-12 with the antibody, or antigen-binding portion thereof, of claim 1 such that human IL-12 is detected. 140. The method of claim 139, wherein human IL-12 is detected in vitro. 141. The method of claim 139, wherein human IL-12 is detected in a biological sample for diagnostic purposes.
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RELATED APPLICATIONS This application is a divisional of U.S. patent application Ser. No. 09/534,717, filed Mar. 24, 2000, which is a non-provisional application claiming priority to U.S. provisional application Ser. No. 60/126,603, filed Mar. 25, 1999, the contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION Human interleukin 12 (IL-12) has recently been characterized as a cytokine with a unique structure and pleiotropic effects (Kobayashi, et al. (1989) J Exp Med. 170:827-845; Seder, et al. (1993) Proc. Natl. Acad. Sci. 90:10188-10192; Ling, et al. (1995) J Exp Med. 154:116-127; Podlaski, et al. (1992) Arch. Biochem. Biophys. 294:230-237). IL-12 plays a critical role in the pathology associated with several diseases involving immune and inflammatory responses. A review of IL-12, its biological activities, and its role in disease can be found in Gately et al. (1998) Ann. Rev. Immunol. 16: 495-521. Structurally, IL-12 is a heterodimeric protein comprising a 35 kDa subunit (p35) and a 40 kDa subunit (p40) which are both linked together by a disulfide bridge (referred to as the “p70 subunit”). The heterodimeric protein is produced primarily by antigen-presenting cells such as monocytes, macrophages and dendritic cells. These cell types also secrete an excess of the p40 subunit relative to p70 subunit. The p40 and p35 subunits are genetically unrelated and neither has been reported to possess biological activity, although the p40 homodimer may function as an IL-12 antagonist. Functionally, IL-12 plays a central role in regulating the balance between antigen specific T helper type (Th1) and type 2 (Th2) lymphocytes. The Th1 and Th2 cells govern the initiation and progression of autoimmune disorders, and IL-12 is critical in the regulation of Th1 lymphocyte differentiation and maturation. Cytokines released by the Th1 cells are inflammatory and include interferon y (IFNγ), IL-2 and lymphotoxin (LT). Th2 cells secrete IL-4, IL-5, IL-6, IL-10 and IL-13 to facilitate humoral immunity, allergic reactions, and immunosuppression. Consistent with the preponderance of Th1 responses in autoimmune diseases and the proinflammatory activities of IFNγ, IL-12 may play a major role in the pathology associated with many autoimmune and inflammatory diseases such as rheumatoid arthritis (RA), multiple sclerosis (MS), and Crohn's disease. Human patients with MS have demonstrated an increase in IL-12 expression as documented by p40 mRNA levels in acute MS plaques. (Windhagen et al., (1995) J. Exp. Med. 182: 1985-1996). In addition, ex vivo stimulation of antigen-presenting cells with CD40L-expressing T cells from MS patients resulted in increased IL-12 production compared with control T cells, consistent with the observation that CD40/CD40L interactions are potent inducers of IL-12. Elevated levels of IL-12 p70 have been detected in the synovia of RA patients compared with healthy controls (Morita et al (1998) Arthritis and Rheumatism. 41: 306-314). Cytokine messenger ribonucleic acid (mRNA) expression profile in the RA synovia identified predominantly Th1 cytokines. (Bucht et al., (1996) Clin. Exp. Immunol. 103: 347-367). IL-12 also appears to play a critical role in the pathology associated with Crohn's disease (CD). Increased expression of INFγ and IL-12 has been observed in the intestinal mucosa of patients with this disease (Fais et al. (1994) J Interferon Res. 14:235-238; Parronchi et al., (1997) Am. J. Path. 150:823-832; Monteleone et al., (1997) Gastroenterology. 112:1169-1178, and Berrebi et al., (1998) Am. J. Path 152:667-672). The cytokine secretion profile of T cells from the lamina propria of CD patients is characteristic of a predominantly Th1 response, including greatly elevated IFNγ levels (Fuss, et al., (1996) J. Immunol. 157:1261-1270). Moreover, colon tissue sections from CD patients show an abundance of IL-12 expressing macrophages and IFNγ expressing T cells (Parronchi et al (1997) Am. J. Path. 150:823-832). Due to the role of human IL-12 in a variety of human disorders, therapeutic strategies have been designed to inhibit or counteract IL-12 activity. In particular, antibodies that bind to, and neutralize, IL-12 have been sought as a means to inhibit IL-12 activity. Some of the earliest antibodies were murine monoclonal antibodies (mAbs), secreted by hybridomas prepared from lymphocytes of mice immunized with IL-12 (see e.g., World Patent Application Publication No. WO 97/15327 by Strober et al.; Neurath et al. (1995) J. Exp. Med. 182:1281-1290; Duchmann et al. (1996) J. Immunol. 26:934-938). These murine IL-12 antibodies are limited for their use in vivo due to problems associated with administration of mouse antibodies to humans, such as short serum half life, an inability to trigger certain human effector functions and elicitation of an unwanted immune response against the mouse antibody in a human (the “human anti-mouse antibody” (HAMA) reaction). In general, attempts to overcome the problems associated with use of fully-murine antibodies in humans, have involved genetically engineering the antibodies to be more “human-like.” For example, chimeric antibodies, in which the variable regions of the antibody chains are murine-derived and the constant regions of the antibody chains are human-derived, have been prepared (Junghans, et al. (1990) Cancer Res. 50:1495-1502; Brown et al. (1991) Proc. Natl. Acad. Sci. 88:2663-2667; Kettleborough et al. (1991) Protein Engineering. 4:773-783). However, because these chimeric and humanized antibodies still retain some murine sequences, they still may elicit an unwanted immune reaction, the human anti-chimeric antibody (HACA) reaction, especially when administered for prolonged periods. A preferred IL-12 inhibitory agent to murine antibodies or derivatives thereof (e.g., chimeric or humanized antibodies) would be an entirely human anti-IL-12 antibody, since such an agent should not elicit the HAMA reaction, even if used for prolonged periods. However, such antibodies have not been described in the art and, therefore are still needed. SUMMARY OF THE INVENTION The present invention provides human antibodies that bind human IL-12. The invention also relates to the treatment or prevention of acute or chronic diseases or conditions whose pathology involves IL-12, using the human anti-IL-12 antibodies of the invention. In one aspect, the invention provides an isolated human antibody, or an antigen-binding portion thereof, that binds to human IL-12. In one embodiment, the invention provides a selectively mutated human IL-12 antibody, comprising: a human antibody or antigen-binding portion thereof, selectively mutated at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue such that it binds to human IL-12. In a preferred embodiment, the invention provides a selectively mutated human IL-12 antibody, comprising: a human antibody or antigen-binding portion thereof, selectively mutated at a preferred selective mutagenesis position with an activity enhancing amino acid residue such that it binds to human IL-12. In another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof is selectively mutated at more than one preferred selective mutagenesis position, contact or hypermutation positions with an activity enhancing amino acid residue. In another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof is selectively mutated at no more than three preferred selective mutagenesis positions, contact or hypermutation positions. In another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof is selectively mutated at no more than two preferred selective mutagenesis position, contact or hypermutation positions. In yet another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof, is selectively mutated such that a target specificity affinity level is attained, the target level being improved over that attainable when selecting for an antibody against the same antigen using phage display technology. In another preferred embodiment, the selectively mutated human IL-12 antibody further retains at least one desirable property or characteristic, e.g., preservation of non-cross reactivity with other proteins or human tissues, preservation of epitope recognition, production of an antibody with a close to a germline immunoglobulin sequence. In another embodiment, the invention provides an isolated human antibody, or antigen-binding portion thereof, that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6 M or less. More preferably, the isolated human antibody or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−2 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−7 M or less. More preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−3 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−8 M or less. More preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−4 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less. More preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−5 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−10 M or less. Even more preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−5 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−11M or less. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−6 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3; and has a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and has a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. In a preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 7; and has a light chain variable region comprising the amino acid sequence of SEQ ID NO: 8. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11; and has a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and has a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. In a preferred embodiment, the isolated human antibody has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 15; and has a light chain variable region comprising the amino acid sequence of SEQ ID NO: 16. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19; and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In a preferred embodiment, the isolated human antibody comprises a heavy chain constant region selected from the group consisting of IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions or any allelic variation thereof as discussed in Kabat et al. (Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242), included herein by reference. In a more preferred embodiment, the antibody heavy chain constant region is IgG1. In another preferred embodiment, the isolated human antibody is a Fab fragment, or a F(ab′)2 fragment or a single chain Fv fragment. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 404-SEQ ID NO: 469; and c) has a light chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 534-SEQ ID NO: 579. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO:335-SEQ ID NO: 403; and a light chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 506-SEQ ID NO: 533. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 288-SEQ ID NO: 334; and a light chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 470-SEQ ID NO: 505. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, comprising a the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In a preferred embodiment, the isolated human antibody comprises a heavy chain constant region, or an Fab fragment or a F(ab′)2 fragment or a single chain Fv fragment as described above. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, which has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 32. In a preferred embodiment, the isolated human antibody comprises a heavy chain constant region, or an Fab fragment, or a F(ab′)2 fragment or a single chain Fv fragment as described above. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−6 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 1 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 1, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22, or a mutant thereof having one or more amino acid substitutions at preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. The invention also provides nucleic acid molecules encoding antibodies, or antigen binding portions thereof, of the invention. A preferred isolated nucleic acid encodes the heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17. The isolated nucleic acid encoding an antibody heavy chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 19. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 21. In another embodiment, the isolated nucleic acid encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23. In another embodiment, the isolated nucleic acid encodes the light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. The isolated nucleic acid encoding an antibody light chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 20. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 22. In another embodiment, the isolated nucleic acid encodes an antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. A preferred isolated nucleic acid encodes the heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25. The isolated nucleic acid encoding an antibody heavy chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 27. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 29. In another embodiment, the isolated nucleic acid encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31. In another embodiment, the isolated nucleic acid encodes the light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. The isolated nucleic acid encoding an antibody light chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 28. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 30. In another embodiment, the isolated nucleic acid encodes an antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 32. In another aspect, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the VH3 germline family, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from a member of the Vλ1 germline family, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact position or hypermutation position with an activity enhancing amino acid residue. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 595-667, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact position or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 669-675, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising the COS-3 germline amino acid sequence, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising the DPL8 germline amino acid sequence, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the VH3 germline family, wherein the heavy chain variable region comprises a CDR2 that is structurally similar to CDR2s from other VH3 germline family members, and a CDR1 that is structurally similar to CDR1 s from other VH3 germline family members, and wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue; c) has a light chain variable region comprising an amino acid sequence selected from a member of the Vλ1 germline family, wherein the light chain variable region comprises a CDR2 that is structurally similar to CDR2s from other Vλ1 germline family members, and a CDR1 that is structurally similar to CDR1s from other Vλ1 germline family members, and wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In a preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the heavy chain CDR3. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the light chain CDR3. In another embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the heavy chain CDR2. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the light chain CDR2. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the heavy chain CDR1. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the light chain CDR1. In another aspect, the invention provides recombinant expression vectors carrying the antibody-encoding nucleic acids of the invention, and host cells into which such vectors have been introduced, are also encompassed by the invention, as are methods of making the antibodies of the invention by culturing the host cells of the invention. In another aspect, the invention provides an isolated human antibody, or antigen-binding portion thereof, that neutralizes the activity of human IL-12, and at least one additional primate IL-12 selected from the group consisting of baboon IL-12, marmoset IL-12, chimpanzee IL-12, cynomolgus IL-12 and rhesus IL-12, but which does not neutralize the activity of the mouse IL-12. In another aspect, the invention provides a pharmaceutical composition comprising the antibody or an antigen binding portion thereof, of the invention and a pharmaceutically acceptable carrier. In another aspect, the invention provides a composition comprising the antibody or an antigen binding portion thereof, and an additional agent, for example, a therapeutic agent. In another aspect, the invention provides a method for inhibiting human IL-12 activity comprising contacting human IL-12 with the antibody of the invention, e.g., J695, such that human IL-12 activity is inhibited. In another aspect, the invention provides a method for inhibiting human IL-12 activity in a human subject suffering from a disorder in which IL-12 activity is detrimental, comprising administering to the human subject the antibody of the invention, e.g., J695, such that human IL-12 activity in the human subject is inhibited. The disorder can be, for example, Crohn's disease, multiple sclerosis or rheumatoid arthritis. In another aspect, the invention features a method for improving the activity of an antibody, or an antigen binding portion thereof, to attain a predetermined target activity, comprising: a) providing a parent antibody a antigen-binding portion thereof, b) selecting a preferred selective mutagenesis position selected from group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. c) individually mutating the selected preferred selective mutagenesis position to at least two other amino acid residues to hereby create a first panel of mutated antibodies, or antigen binding portions thereof; d) evaluating the activity of the first panel of mutated antibodies, or antigen binding portions thereof to determined if mutation of a single selective mutagenesis position produces an antibody or antigen binding portion thereof with the predetermined target activity or a partial target activity; e) combining in a stepwise fashion, in the parent antibody, or antigen binding portion thereof, individual mutations shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof. f) evaluating the activity of the combination antibodies, or antigen binding portions thereof to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity. g) if steps d) or f) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result an antibody with only a partial activity, additional amino acid residues selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 are mutated to at least two other amino acid residues to thereby create a second panel of mutated antibodies or antigen-binding portions thereof; h) evaluating the activity of the second panel of mutated antibodies or antigen binding portions thereof, to determined if mutation of a single amino acid residue selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 results an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; i) combining in stepwise fashion in the parent antibody, or antigen-binding portion thereof, individual mutations of step g) shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof; j) evaluating the activity of the combination antibodies or antigen binding portions thereof, to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity; k) if steps h) or j) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result in an antibody with only a partial activity, additional amino acid residues selected from the group consisting of H33B, H52B and L31A are mutated to at least two other amino acid residues to thereby create a third panel of mutated antibodies or antigen binding portions thereof, l) evaluating the activity of the third panel of mutated antibodies or antigen binding portions thereof, to determine if a mutation of a single amino acid residue selected from the group consisting of H33B, H52B and L31A resulted in an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; m) combining in a stepwise fashion in the parent antibody, or antigen binding portion thereof, individual mutation of step k) shown to have an improved activity, to form combination antibodies, or antigen binding portions, thereof; n) evaluating the activity of the combination antibodies or antigen-binding portions thereof, to determine if the combination antibodies, or antigen binding portions thereof have the predetermined target activity to thereby produce an antibody or antigen binding portion thereof with a predetermined target activity. In another aspect, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof, b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) repeating steps b) through d) for at least one other contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In one embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity is not further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) repeating steps b) through d) for at least one other contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expressing said panel in an appropriate expression system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristics, wherein the property or characteristic is one that needs to be retained in the antibody; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment of the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least on retained property or characteristic, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristics, wherein the property or characteristic is one that needs to be retained; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least on retained other characteristic, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and, expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other position within the CDR which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and other property or characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies or antigen-binding portions thereof, relative to the parent antibody or antigen-portion thereof, for changes in at least one other property or characteristic; f) repeating steps b) through e) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not affecting at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof, and h) evaluating the activity and the retention of at least one other characteristic or property of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment the invention provides a method to improve the affinity of an antibody or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other characteristic or property until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies or antigen-binding portions thereof, relative to the parent antibody or antigen-portion thereof, for changes in at least one other property or characteristic; f) repeating steps b) through e) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity but not affecting at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof with at least one retained property or characteristic; and h) evaluating the activity and the retention of at least one property of characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, without affecting other characteristics, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity and retained other characteristic or property, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity and retention of at least one other characteristic or property of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b nor other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not to affect at least one other characteristic or property, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and retention of at least one other characteristic or property of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one other retained characteristic or property, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1B show the heavy chain variable region amino acid sequence alignments of a series of human antibodies that bind human IL-12 compared to germline sequences Cos-3/JH3 and Dp118 Lv1042. Kabat numbering is used to identify amino acid positions. For the Joe 9 wild type, the full sequence is shown. For the other antibodies, only those amino acids positions that differ from Joe 9 wild type are shown. FIGS. 1C-1D show the light chain variable region amino acid sequence alignments of a series of human antibodies that bind human IL-12. Kabat numbering is used to identify amino acid positions. For the Joe 9 wild type, the full sequence is shown. For the other antibodies, only those amino acids positions that differ from Joe 9 wild type are shown. FIGS. 2A-2E show the CDR positions in the heavy chain of the Y61 antibody that were mutated by site-directed mutagenesis and the respective amino acid substitutions at each position. The graphs at the right of the figures show the off-rates for the substituted antibodies (black bars) as compared to unmutated Y61 (open bar). FIGS. 2F-2H show the CDR positions in the light chain of the Y61 antibody that were mutated by site-directed mutagenesis and the respective amino acid substitutions at each position. The graphs at the right of the figures show the off-rates for the substituted antibodies (black bars) as compared to unmutated Y61 (open bar). FIG. 3 demonstrates the in vivo efficacy of the human anti-IL-12 antibody J695, on plasma neopterin levels in cynomolgus monkeys. FIG. 4 shows a graph of mean arthritic score versus days after immunization of mice with collagen, demonstrating that treatment with C17.15 significantly decreases arthritis-related symptoms as compared to treatment with rat IgG. DETAILED DESCRIPTION OF THE INVENTION In order that the present invention may be more readily understood, certain terms are first defined. The term “activity enhancing amino acid residue” includes an amino acid residue which improves the activity of the antibody. It should be understood that the activity enhancing amino acid residue may replace an amino acid residue at a contact, hypermutation or preferred selective mutagenesis position and, further, more than one activity enhancing amino acid residue can be present within one or more CDRs. An activity enhancing amino acid residue include, an amino acid residue that improves the binding specificity/affinity of an antibody, for example anti-human IL-12 antibody binding to human IL-12. The activity enhancing amino acid residue is also intended to include an amino acid residue that improves the neutralization potency of an antibody, for example, the human IL-12 antibody which inhibits human IL-12. The term “antibody” includes an immunoglobulin molecule comprised of four polypeptide chains, two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds. Each heavy chain is comprised of a heavy chain variable region (abbreviated herein as HCVR or VH) and a heavy chain constant region. The heavy chain constant region is comprised of three domains, CH1, CH2 and CH3. Each light chain is comprised of a light chain variable region (abbreviated herein as LCVR or VL) and a light chain constant region. The light chain constant region is comprised of one domain, CL. The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDRs), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The term “antigen-binding portion” of an antibody (or “antibody portion”) includes fragments of an antibody that retain the ability to specifically bind to an antigen (e.g., hIL-12). It has been shown that the antigen-binding function of an antibody can be performed by fragments of a full-length antibody. Examples of binding fragments encompassed within the term “antigen-binding portion” of an antibody include (i) a Fab fragment, a monovalent fragment consisting of the VL, VH, CL and CH1 domains; (ii) a F(ab′)2 fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the VH and CH1 domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb fragment (Ward et al., (1989) Nature 341:544-546), which consists of a VH domain; and (vi) an isolated complementarity determining region (CDR). Furthermore, although the two domains of the Fv fragment, VL and VH, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH regions pair to form monovalent molecules (known as single chain Fv (scFv); see e.g., Bird et al. (1988) Science 242:423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883). Such single chain antibodies are also intended to be encompassed within the term “antigen-binding portion” of an antibody. Other forms of single chain antibodies, such as diabodies are also encompassed. Diabodies are bivalent, bispecific antibodies in which VH and VL domains are expressed on a single polypeptide chain, but using a linker that is too short to allow for pairing between the two domains on the same chain, thereby forcing the domains to pair with complementary domains of another chain and creating two antigen binding sites (see e.g., Holliger, P., et al. (1993) Proc. Natl. Acad. Sci. USA 90:6444-6448; Poljak, R. J., et al. (1994) Structure 2:1121-1123). Still further, an antibody or antigen-binding portion thereof may be part of a larger immunoadhesion molecules, formed by covalent or non-covalent association of the antibody or antibody portion with one or more other proteins or peptides. Examples of such immunoadhesion molecules include use of the streptavidin core region to make a tetrameric scFv molecule (Kipriyanov, S. M., et al. (1995) Human Antibodies and Hybridomas 6:93-101) and use of a cysteine residue, a marker peptide and a C-terminal polyhistidine tag to make bivalent and biotinylated scFv molecules (Kipriyanov, S. M., et al. (1994) Mol. Immunol. 31:1047-1058). Antibody portions, such as Fab and F(ab′)2 fragments, can be prepared from whole antibodies using conventional techniques, such as papain or pepsin digestion, respectively, of whole antibodies. Moreover, antibodies, antibody portions and immunoadhesion molecules can be obtained using standard recombinant DNA techniques, as described herein. Preferred antigen binding portions are complete domains or pairs of complete domains. The term “backmutation” refers to a process in which some or all of the somatically mutated amino acids of a human antibody are replaced with the corresponding germline residues from a homologous germline antibody sequence. The heavy and light chain sequences of the human antibody of the invention are aligned separately with the germline sequences in the VBASE database to identify the sequences with the highest homology. Differences in the human antibody of the invention are returned to the germline sequence by mutating defined nucleotide positions encoding such different amino acid. The role of each amino acid thus identified as candidate for backmutation should be investigated for a direct or indirect role in antigen binding and any amino acid found after mutation to affect any desirable characteristic of the human antibody should not be included in the final human antibody; as an example, activity enhancing amino acids identified by the selective mutagenesis approach will not be subject to backmutation. To minimize the number of amino acids subject to backmutation those amino acid positions found to be different from the closest germline sequence but identical to the corresponding amino acid in a second germline sequence can remain, provided that the second germline sequence is identical and colinear to the sequence of the human antibody of the invention for at least 10, preferably 12 amino acids, on both sides of the amino acid in question. Backmuation may occur at any stage of antibody optimization; preferably, backmutation occurs directly before or after the selective mutagenesis approach. More preferably, backmutation occurs directly before the selective mutagenesis approach. The phrase “human interleukin 12” (abbreviated herein as hIL-12, or IL-12), as used herein, includes a human cytokine that is secreted primarily by macrophages and dendritic cells. The term includes a heterodimeric protein comprising a 35 kD subunit (p35) and a 40 kD subunit (p40) which are both linked together with a disulfide bridge. The heterodimeric protein is referred to as a “p70 subunit”. The structure of human IL-12 is described further in, for example, Kobayashi, et al. (1989) J. Exp. Med. 170:827-845; Seder, et al. (1993) Proc. Natl. Acad. Sci. 90:10188-10192; Ling, et al. (1995) J Exp Med. 154:116-127; Podlaski, et al. (1992) Arch. Biochem. Biophys. 294:230-237. The term human IL-12 is intended to include recombinant human IL-112 (rb IL-12), which can be prepared by standard recombinant expression methods. The terms “Kabat numbering”, “Kabat definitions” and “Kabat labeling” are used interchangeably herein. These terms, which are recognized in the art, refer to a system of numbering amino acid residues which are more variable (i.e. hypervariable) than other amino acid residues in the heavy and light chain variable regions of an antibody, or an antigen binding portion thereof (Kabat et al. (1971) Ann. NY Acad, Sci. 190:382-391 and, Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). For the heavy chain variable region, the hypervariable region ranges from amino acid positions 31 to 35 for CDR1, amino acid positions 50 to 65 for CDR2, and amino acid positions 95 to 102 for CDR3. For the light chain variable region, the hypervariable region ranges from amino acid positions 24 to 34 for CDR1, amino acid positions 50 to 56 for CDR2, and amino acid positions 89 to 97 for CDR3. The Kabat numbering is used herein to indicate the positions of amino acid modifications made in antibodies of the invention. For example, the Y61 anti-IL-12 antibody can be mutated from serine (S) to glutamic acid (E) at position 31 of the heavy chain CDR1 (H31S→E), or glycine (G) can be mutated to tyrosine (Y) at position 94 of the light chain CDR3 (L94G→Y). The term “human antibody” includes antibodies having variable and constant regions corresponding to human germline immunoglobulin sequences as described by Kabat et al. (See Kabat, et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). The human antibodies of the invention may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo), for example in the CDRs and in particular CDR3. The mutations preferably are introduced using the “selective mutagenesis approach” described herein. The human antibody can have at least one position replaced with an amino acid residue, e.g., an activity enhancing amino acid residue which is not encoded by the human germline immunoglobulin sequence. The human antibody can have up to twenty positions replaced with amino acid residues which are not part of the human germline immunoglobulin sequence. In other embodiments, up to ten, up to five, up to three or up to two positions are replaced. In a preferred embodiment, these replacements are within the CDR regions as described in detail below. However, the term “human antibody”, as used herein, is not intended to include antibodies in which CDR sequences derived from the germline of another mammalian species, such as a mouse, have been grafted onto human framework sequences. The phrase “recombinant human antibody” includes human antibodies that are prepared, expressed, created or isolated by recombinant means, such as antibodies expressed using a recombinant expression vector transfected into a host cell (described further in Section II, below), antibodies isolated from a recombinant, combinatorial human antibody library (described further in Section III, below), antibodies isolated from an animal (e.g., a mouse) that is transgenic for human immunoglobulin genes (see e.g., Taylor, L. D., et al. (1992) Nucl. Acids Res. 20:6287-6295) or antibodies prepared, expressed, created or isolated by any other means that involves splicing of human immunoglobulin gene sequences to other DNA sequences. Such recombinant human antibodies have variable and constant regions derived from human germline immunoglobulin sequences (See Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). In certain embodiments, however, such recombinant human antibodies are subjected to in vitro mutagenesis (or, when an animal transgenic for human Ig sequences is used, in vivo somatic mutagenesis) and thus the amino acid sequences of the VH and VL regions of the recombinant antibodies are sequences that, while derived from and related to human germline VH and VL sequences, may not naturally exist within the human antibody germline repertoire in vivo. In certain embodiments, however, such recombinant antibodies are the result of selective mutagenesis approach or backmutation or both. An “isolated antibody” includes an antibody that is substantially free of other antibodies having different antigenic specificities (e.g., an isolated antibody that specifically binds hIL-12 is substantially free of antibodies that specifically bind antigens other than hIL-12). An isolated antibody that specifically binds hIL-12 may bind IL-12 molecules from other species (discussed in further detail below). Moreover, an isolated antibody may be substantially free of other cellular material and/or chemicals. A “neutralizing antibody” (or an “antibody that neutralized hIL-12 activity”) includes an antibody whose binding to hIL-12 results in inhibition of the biological activity of hIL-12. This inhibition of the biological activity of hIL-12 can be assessed by measuring one or more indicators of hIL-12 biological activity, such as inhibition of human phytohemagglutinin blast proliferation in a phytohemagglutinin blast proliferation assay (PHA), or inhibition of receptor binding in a human IL-12 receptor binding assay (see Example 3-Interferon-gamma Induction Assay). These indicators of hIL-12 biological activity can be assessed by one or more of several standard in vitro or in vivo assays known in the art (see Example 3). The term “activity” includes activities such as the binding specificity/affinity of an antibody for an antigen, for example, an anti-hIL-12 antibody that binds to an IL-12 antigen and/or the neutralizing potency of an antibody, for example, an anti-hIL-12 antibody whose binding to hIL-12 inhibits the biological activity of hIL-12, e.g. inhibition of PHA blast proliferation or inhibition of receptor binding in a human IL-12 receptor binding assay (see Example 3). The phrase “surface plasmon resonance” includes an optical phenomenon that allows for the analysis of real-time biospecific interactions by detection of alterations in protein concentrations within a biosensor matrix, for example using the BIAcore system (Pharmacia Biosensor AB, Uppsala, Sweden and Piscataway, N.J.). For further descriptions, see Example 5 and Jönsson, U., et al. (1993) Ann. Biol. Clin. 51:19-26; Jönsson, U., et al. (1991) Biotechniques 11:620-627; Johnsson, B., et al. (1995) J. Mol. Recognit. 8:125-131; and Johnnson, B., et al. (1991) Anal. Biochem. 198:268-277. The term “Koff”, as used herein, is intended to refer to the off rate constant for dissociation of an antibody from the antibody/antigen complex. The term “Kd”, as used herein, is intended to refer to the dissociation constant of a particular antibody-antigen interaction. The phrase “nucleic acid molecule” includes DNA molecules and RNA molecules. A nucleic acid molecule may be single-stranded or double-stranded, but preferably is double-stranded DNA. The phrase “isolated nucleic acid molecule”, as used herein in reference to nucleic acids encoding antibodies or antibody portions (e.g., VH, VL, CDR3) that bind hIL-12 including “isolated antibodies”), includes a nucleic acid molecule in which the nucleotide sequences encoding the antibody or antibody portion are free of other nucleotide sequences encoding antibodies or antibody portions that bind antigens other than hIL-12, which other sequences may naturally flank the nucleic acid in human genomic DNA. Thus, for example, an isolated nucleic acid of the invention encoding a VH region of an anti-IL-12 antibody contains no other sequences encoding other VH regions that bind antigens other than IL-12. The phrase “isolated nucleic acid molecule” is also intended to include sequences encoding bivalent, bispecific antibodies, such as diabodies in which VH and VL regions contain no other sequences other than the sequences of the diabody. The term “vector” includes a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid”, which refers to a circular double stranded DNA loop into which additional DNA segments may be ligated. Another type of vector is a viral vector, wherein additional DNA segments may be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply, “expression vectors”). In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, “plasmid” and “vector” may be used interchangeably as the plasmid is the most commonly used form of vector. However, the invention is intended to include such other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions. The phrase “recombinant host cell” (or simply “host cell”) includes a cell into which a recombinant expression vector has been introduced. It should be understood that such terms are intended to refer not only to the particular subject cell but to the progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term “host cell” as used herein. The term “modifying”, as used herein, is intended to refer to changing one or more amino acids in the antibodies or antigen-binding portions thereof. The change can be produced by adding, substituting or deleting an amino acid at one or more positions. The change can be produced using known techniques, such as PCR mutagenesis. The phrase “contact position” includes an amino acid position of in the CDR1, CDR2 or CDR3 of the heavy chain variable region or the light chain variable region of an antibody which is occupied by an amino acid that contacts antigen in one of the twenty-six known antibody-antigen structures. If a CDR amino acid in any of the 26 known solved structures of antibody-antigen complexes contacts the antigen, then that amino acid can be considered to occupy a contact position. Contact positions have a higher probability of being occupied by an amino acid which contact antigen than non-contact positions. Preferably a contact position is a CDR position which contains an amino acid that contacts antigen in greater than 3 of the 26 structures (>11.5%). Most preferably a contact position is a CDR position which contains an amino acid that contacts antigen in greater than 8 of the 25 structures (>32%). The term “hypermutation position” includes an amino acid residue that occupies position in the CDR1, CDR2 or CDR3 region of the heavy chain variable region or the light chain variable region of an antibody that is considered to have a high frequency or probability for somatic hypermutation during in vivo affinity maturation of the antibody. “High frequency or probability for somatic hypermutation” includes frequencies or probabilities of a 5 to about 40% chance that the residue will undergo somatic hypermutation during in vivo affinity maturation of the antibody. It should be understood that all ranges within this stated range are also intended to be part of this invention, e.g., 5 to about 30%, e.g., 5 to about 15%, e.g., 15 to about 30%. The term “preferred selective mutagenesis position” includes an amino acid residue that occupies a position in the CDR1, CDR2 or CDR3 region of the heavy chain variable region or the light chain variable region which can be considered to be both a contact and a hypermutation position. The phrase “selective mutagenesis approach” includes a method of improving the activity of an antibody by selecting and individually mutating CDR amino acids at at least one preferred selective mutagenesis position, hypermutation, and/or contact position. A “selectively mutated” human antibody is an antibody which contains a mutation at a position selected using a selective mutagenesis approach. In another embodiment, the selective mutagenesis approach is intended to provide a method of preferentially mutating selected individual amino acid residues in the CDR 1, CDR2 or CDR3 of the heavy chain variable region (hereinafter H1, H2, and H3, respectively), or the CDR1, CDR2 or CDR3 of the light chain variable region (hereinafter referred to as L1, L2, and L3, respectively) of an antibody. Amino acid residues may be selected from preferred selective mutagenesis positions, contact positions., or hypermutation positions. Individual amino acids are selected based on their position in the light or heavy chain variable region. It should be understood that a hypermutation position can also be a contact position. In an embodiment, the selective mutagenesis approach is a “targeted approach”. The language “targeted approach” is intended to include a method of preferentially mutating selected individual amino acid residues in the CDR1, CDR2 or CDR3 of the heavy chain variable region or the CDR1, CDR2 or CDR3 of the light chain variable region of an antibody in a targeted manner, e.g., a “Group-wise targeted approach” or “CDR-wise targeted approach”. In the “Group-wise targeted approach”, individual amino acid residues in particular groups are targeted for selective mutations including groups I (including L3 and H3), II (including H2 and L1) and III (including L2 and H1), the groups being listed in order of preference for targeting. In the “CDR-wise targeted approach”, individual amino acid residues in particular CDRs are targeted for selective mutations with the order of preference for targeting as follows: H3, L3, H2, L1, H1 and L2. The selected amino acid residue is mutated, e.g., to at least two other amino acid residues, and the effect of the mutation on the activity of the antibody is determined. Activity is measured as a change in the binding specificity/affinity of the antibody, and/or neutralization potency of the antibody. It should be understood that the selective mutagenesis approach can be used for the optimization of any antibody derived from any source including phage display, transgenic animals with human IgG germline genes, human antibodies isolated from human B-cells. Preferably, the selective mutagenesis approach is used on antibodies which can not be optimized further using phage display technology. It should be understood that antibodies from any source including phage display, transgenic animals with human IgG germline genes, human antibodies isolated from human B-cells can be subject to backmutation prior to or after the selective mutagenesis approach. The term “activity enhancing amino acid residue” includes an amino acid residue which improves the activity of the antibody. It should be understood that the activity enhancing amino acid residue may replace an amino acid residue at a preferred selective mutagenesis position, contact position, or a hypermutation position and, further, more than one activity enhancing amino acid residue can be present within one or more CDRs. An activity enhancing amino acid residue include, an amino acid residue that improves the binding specificity/affinity of an antibody, for example anti-human IL-12 antibody binding to human IL-12. The activity enhancing amino acid residue is also intended to include an amino acid residue that improves the neutralization potency of an antibody, for example, the human IL-12 antibody which inhibits human IL-12. Various aspects of the invention are described in further detail in the following subsections. I. Human Antibodies That Bind Human IL-12 This invention provides isolated human antibodies, or antigen-binding portions thereof, that bind to human IL-12. Preferably, the human antibodies of the invention are recombinant, neutralizing human anti-hIL-12 antibodies. Antibodies of the invention that bind to human IL-12 can be selected, for example, by screening one or more human VL and VH cDNA libraries with hIL-12, such as by phage display techniques as described in Example 1. Screening of human VL and VH cDNA libraries initially identified a series of anti-IL-12 antibodies of which one antibody, referred to herein as “Joe 9” (or “Joe 9 wild type”), was selected for further development. Joe 9 is a relatively low affinity human IL-12 antibody (e.g., a Koff of about 0.1 sec−1), yet is useful for specifically binding and detecting hIL-12. The affinity of the Joe 9 antibody was improved by conducting mutagenesis of the heavy and light chain CDRs, producing a panel of light and heavy chain variable regions that were “mixed and matched” and further mutated, leading to numerous additional anti-hIL-12 antibodies with increased affinity for hIL-12 (see Example 1, Table 2 (see Appendix A) and the sequence alignments of FIGS. 1A-D). Of these antibodies, the human anti-hIL-12 antibody referred to herein as Y61 demonstrated a significant improvement in binding affinity (e.g., a Koff of about 2×10−4 sec-1). The Y61 anti-hIL-12 antibody was selected for further affinity maturation by individually mutating specific amino acids residues within the heavy and light chain CDRs. Amino acids residues of Y61 were selected for site-specific mutation (selective mutagenesis approach) based on the amino acid residue occupying a preferred selective mutagenesis position, contact and/or a hypermutation position. A summary of the substitutions at selected positions in the heavy and light chain CDRs is shown in FIGS. 2A-2H. A preferred recombinant neutralizing antibody of the invention, referred to herein as J695, resulted from a Gly to Tyr substitution at position 50 of the light chain CDR2 of Y61, and a Gly to Tyr substitution at position 94 of the light chain CDR3 of Y61. Amino acid sequence alignments of the heavy and light chain variable regions of a panel of anti-IL-12 antibodies of the invention, on the lineage from Joe 9 wild type to J695, are shown in FIGS. 1A-1D. These sequence alignments allowed for the identification of consensus sequences for preferred heavy and light chain variable regions of antibodies of the invention that bind hIL-12, as well as consensus sequences CDR3, CDR2, and CDR1, on the lineage from Joe 9 to J695. Moreover, the Y61 mutagenesis analysis summarized in FIGS. 2A-2H allowed for the identification of consensus sequences for heavy and light chain variable regions that bind hIL-12, as well as consensus sequences for the CDR3, CDR2, and CDR1 that bind hIL-12 on the lineage from Y61 to J695 that encompasses sequences with modifications from Y61 yet that retain good hIL-12 binding characteristics. Preferred CDR, VH and VL sequences of the invention (including consensus sequences) as identified by sequence identifiers in the attached Sequence Listing, are summarized below. SEQ ID ANTIBODY NO: CHAIN REGION SEQUENCE 1 Consensus CDR H3 (H/S)-G-S-(H/Y)-D-(N/T/Y) Joe 9 to J695 2 Consensus CDR L3 Q-(S/T)-Y-(D/E)-(S/R/K)-(S/G/Y)- Joe 9 to J695 (L/F/T/S)-(R/S/T/W/H)-(G/P)- (S/T/A/L)-(R/S/M/T/L)-(V/I/T/M/L) 3 Consensus CDR H2 F-I-R-Y-D-G-S-N-K-Y-Y-A-D-S-V-K- Joe 9 to J695 G 4 Consensus CDR L2 (G/Y)-N-(D/S)-(Q/N)-R-P-S Joe 9 to J695 5 Consensus CDR H1 F-T-F-S-(S/E)-Y-G-M-H Joe 9 to J695 6 Consensus CDR L1 (S/T)-G-(G/S)-(R/S)-S-N-I-(G/V)- Joe 9 to J695 (S/A)-(N/G/Y)-(T/D)-V-(K/H) 7 Consensus VH (full VH sequence; see Joe 9 to J695 sequence listing) 8 Consensus VL (full VL sequence; see Joe 9 to J695 sequence listing) 9 Consensus CDR H3 H-(G/V/C/H)-(S/T)-(H/T/V/R/I)- Y61 to J695 (D/S)-(N/K/A/T/S/F/W/H) 10 Consensus CDR L3 Q-S-Y-(D/S)-(Xaa)- Y61 to J695 (G/D/Q/L/F/R/H/N/Y)-T-H-P-A-L-L 11 Consensus CDR H2 (F/T/Y)-I-(R/A)-Y-(D/S/E/A)-(G/R)- Y61 to J695 S-(Xaa)-K-(Y/E)-Y-A-D-S-V-K-G 12 Consensus CDR L2 (G/Y/S/T/N/Q)-N-D-Q-R-P-S Y61 to J695 13 Consensus CDR H1 F-T-F-(Xaa)-(Xaa)-(Y/H)- Y61 to J695 (G/M/A/N/S)-M-H 14 Consensus CDR L1 S-G-G-R-S-N-I-G-(S/C/R/N/D/T)- Y61 to J695 (N/M/I)-(T/Y/D/H/K/P)-V-K 15 Consensus VH (full VH sequence; see Y61 to J695 sequence listing) 16 Consensus VL (full VL sequence; see Y61 to J695 sequence listing) 17 Y61 CDR H3 H-G-S-H-D-N 18 Y61 CDR L3 Q-S-Y-D-R-G-T-H-P-A-L-L 19 Y61 CDR H2 F-I-R-Y-D-G-S-N-K-Y-Y-A-D-S-V-K- G 20 Y61 CDR L2 G-N-D-Q-R-P-S 21 Y61 CDR H1 F-T-F-S-S-Y-G-M-H 22 Y61 CDR L1 S-G-G-R-S-N-I-G-S-N-T-V-K 23 Y61 VH (full VH sequence; see sequence listing) 24 Y61 VL (full VL sequence; see sequence listing) 25 J695 CDR H3 H-G-S-H-D-N 26 J695 CDR L3 Q-S-Y-D-R-Y-T-H-P-A-L-L 27 J695 CDR H2 F-I-R-Y-D-G-S-N-K-Y-Y-A-D-S-V-K- G 28 J695 CDR L2 Y-N-D-Q-R-P-S 29 J695 CDR H1 F-T-F-S-S-Y-G-M-H 30 J695 CDR L1 S-G-S-R-S-N-I-G-S-N-T-V-K 31 J695 VH (full VH sequence; see sequence listing) 32 J695 VL (full VL sequence; see sequence listing) Antibodies produced from affinity maturation of Joe 9 wild type were functionally characterized by surface plasmon resonance analysis to determine the Kd and Koff rate. A series of antibodies were produced having a Koff rate within the range of about 0.1 s−1 to about 1×10−5 s−1, and more preferably a Koff of about 1×10−4s−1 to 1×10−5s−1 or less. Antibodies were also characterized in vitro for their ability to inhibit phytohemagglutinin (PHA) blast proliferation, as described in Example 3. A series of antibodies were produced having an IC50 value in the range of about 1×10−6M to about 1×10−11M, more preferably about 1×10−10M to 1×10−11M or less. Accordingly, in one aspect, the invention provides an isolated human antibody, or antigen-binding portion thereof, that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6 M or less. In preferred embodiments, the isolated human IL-12 antibody, or an antigen-portion binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−2s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 Of 1×10−7M or less. In more preferred embodiments, the isolated human IL-12 antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−3 s−1 or less, or inhibits phytohemagglutinin bast proliferation in an in vitro PHA assay with an IC50 of 1×10−8 M or less. In more preferred embodiments, the isolated human IL-12 antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a Koff rate constant of 1×10−4s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less. In more preferred embodiments, the isolated human IL-12 antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a koff rate constant of 1×10−5 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−10 M or less. In even more preferred embodiments, the isolated human IL-12 antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a Koff rate constant of 1×10−5 s−1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−11M or less. The dissociation rate constant (Koff) of an IL-12 antibody can be determined by surface plasmon resonance (see Example 5). Generally, surface plasmon resonance analysis measures real-time binding interactions between ligand (recombinant human IL-112 immobilized on a biosensor matrix) and analyte (antibodies in solution) by surface plasmon resonance (SPR) using the BIAcore system (Pharmacia Biosensor, Piscataway, N.J.). Surface plasmon analysis can also be performed by immobilizing the analyte (antibodies on a biosensor matrix) and presenting the ligand (recombinant IL-12 in solution). Neutralization activity of IL-12 antibodies, or antigen binding portions thereof; can be assessed using one or more of several suitable in vitro assays (see Example 3). It is well known in the art that antibody heavy and light chain CDRs play an important role in the binding specificity/affinity of an antibody for an antigen. Accordingly, the invention encompasses human antibodies having light and heavy chain CDRs of Joe 9, as well as other antibodies having CDRs that have been modified to improve the binding specificity/affinity of the antibody. As demonstrated in Example 1, a series of modifications to the light and heavy chain CDRs results in affinity maturation of human anti-hIL-12 antibodies. The heavy and light chain variable region amino acid sequence alignments of a series of human antibodies ranging from Joe 9 wild type to J695 that bind human IL-12 is shown in FIGS. 1A-1 D. Consensus sequence motifs for the CDRs of antibodies can be determined from the sequence alignment (as summarized in the table above). For example, a consensus motif for the VH CDR3 of the lineage from Joe 9 to J695 comprises the amino acid sequence: (H/S)-G-S-(H/Y)-D-(N/T/Y) (SEQ ID NO: 1), which encompasses amino acids from position 95 to 102 of the consensus HCVR shown in SEQ ID NO: 7. A consensus motif for the VL CDR3 comprises the amino acid sequence: Q-(S/T)-Y-(D/E)-(S/R/K)-(S/G/Y)-(L/F/T/S)-(R/S/T/W/H)-(G/P)-(S/T/A/L)-(R/S/M/T/L-V/I/T/M/L) (SEQ ID NO: 2), which encompasses amino acids from position 89 to 97 of the consensus LCVR shown in SEQ ID NO: 8. Accordingly, in another aspect, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−6 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO:2. In a preferred embodiment, the antibody further comprises a VH CDR2 comprising the amino acid sequence: F-I-R-Y-D-G-S-N-K-Y-Y-A-D-S-V-K-G (SEQ ID NO: 3) (which encompasses amino acids from position 50 to 65 of the consensus HCVR comprising the amino acid sequence SEQ ID NO: 7) and further comprises a VL CDR2 comprising the amino acid sequence: (G/Y)-N-(D/S)-(Q/N)-R-P-S (SEQ ID NO: 4) (which encompasses amino acids from position 50 to 56 of the consensus LCVR comprising the amino acid sequence SEQ ID NO: 8). In another preferred embodiment, the antibody further comprises a VH CDR1 comprising the amino acid sequence: F-T-F-S-(S/E)-Y-G-M-H (SEQ ID NO: 5) (which encompasses amino acids from position 27 to 35 of the consensus HCVR comprising the amino acid sequence SEQ ID NO: 7) and further comprises a VL CDR1 comprising the amino acid sequence: (S/T)-G-(G/S)-(R/S)-S-N-I-(G/V)-(S/A)-(N/G/Y)-(T/D)-V-(K/H) (SEQ ID NO: 6) (which encompasses amino acids from position 24 to 34 of the consensus LCVR comprising the amino acid sequence SEQ ID NO: 8). In yet another preferred embodiment, the antibody of the invention comprises a HCVR comprising the amino acid sequence of SEQ ID NO: 7 and a LCVR comprising the amino acid sequence of SEQ ID NO: 8. Additional consensus motifs can be determined based on the mutational analysis performed on Y61 that led to the J695 antibody (summarized in FIGS. 2A-2H). As demonstrated by the graphs shown in FIGS. 2A-2H, certain residues of the heavy and light chain CDRs of Y61 were amenable to substitution without significantly impairing the hIL-12 binding properties of the antibody. For example, individual substitutions at position 30 in CDR H1 with twelve different amino acid residues did not significantly reduce the Koff rate of the antibody, indicating that is position is amenable to substitution with a variety of different amino acid residues. Thus, based on the mutational analysis (i.e., positions within Y61 that were amenable to substitution by other amino acid residues) consensus motifs were determined. The consensus motifs for the heavy and light chain CDR3s are shown in SEQ ID NOs: 9 and 10, respectively, consensus motifs for the heavy and light chain CDR2s are shown in SEQ ID NOs: 11 and 12, respectively, and consensus motifs for the heavy and light chain CDR1 s are shown in SEQ ID NOs: 13 and 14, respectively. Consensus motifs for the VH and VL regions are shown in SEQ ID NOs: 15 and 16, respectively. Accordingly, in one aspect, the invention features an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10. In a preferred embodiment, the antibody further comprises a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 11 and further comprises a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 12. In another preferred embodiment, the antibody further comprises a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 13 and further comprises a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 14. In yet another preferred embodiment, the antibody of the invention comprises a HCVR comprising the amino acid sequence of SEQ ID NO: 15 and a LCVR comprising the amino acid sequence of SEQ ID NO: 16. A preferred antibody of the invention, the human anti-hIL-12 antibody Y6 was produced by affinity maturation of Joe 9 wild type by PCR mutagenesis of the CDR3 (as described in Example 1). Y61 had an improved specificity/binding affinity determined by surface plasmon resonance and by in vitro neutralization assays. The heavy and light chain CDR3s of Y61 are shown in SEQ ID NOs: 17 and 18, respectively, the heavy and light chain CDR2s of Y61 are shown in SEQ ID NOs: 19 and 20, respectively, and the heavy and light chain CDR1s of Y61 are shown in SEQ ID NOs: 21 and 22, respectively. The VH of Y61 has the amino acid sequence of SEQ ID NO: 23 and the VL of Y61 has the amino acid sequence of SEQ ID NO: 24 (these sequences are also shown in FIGS. 1A-1D, aligned with Joe9). Accordingly, in another aspect, the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19 and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20. In another preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21 and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. In yet another preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, comprising a the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In certain embodiments, the full length antibody comprises a heavy chain constant region, such as IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions, and any allotypic variant therein as described in Kabat (, Kabat, E. A., et al. (1991) Sequences of proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). Preferably, the antibody heavy chain constant region is an IgG1 heavy chain constant region. Alternatively, the antibody portion can be an Fab fragment, an F(ab′2) fragment or a single chain Fv fragment. Modifications of individual residues of Y61 led to the production of a panel of antibodies shown in FIGS. 2A-2H. The specificity/binding affinity of each antibody was determined by surface plasmon resonance and/or by in vitro neutralization assays. Accordingly, in another aspect, the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 404-SEQ ID NO: 469; and c) has a light chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 534-SEQ ID NO: 579. In preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO:335-SEQ ID NO: 403; and a light chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 506-SEQ ID NO: 533. In another preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 288-SEQ ID NO: 334; and a light chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 470-SEQ ID NO: 505. In yet another preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, comprising a the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In certain embodiments, the full length antibody comprising a heavy chain constant region such as IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions and any allotypic variant therein as described in Kabat (, Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). Preferably, the antibody heavy chain constant region is an IgG1 heavy chain constant region. Alternatively, the antibody portion can be a Fab fragment, an F(ab′2) fragment or a single chain Fv fragment. A particularly preferred recombinant, neutralizing antibody of the invention, J695, was produced by site-directed mutagenesis of contact and hypermutation amino acids residues of antibody Y61 (see Example 2 and section III below). J695 differs from Y61 by a Gly to Tyr substitution in Y61 at position 50 of the light chain CDR2 and by a Gly to Tyr substitution at position 94 of the light chain CDR3. The heavy and light chain CDR3s of J695 are shown in SEQ ID NOs: 25 and 26, respectively, the heavy and light chain CDR2s of J695 are shown in SEQ ID NOs: 27 and 28, respectively, and the heavy and light chain CDR1s of J695 are shown in SEQ ID NOs: 29 and 30, respectively. The VH of J695 has the amino acid sequence of SEQ ID NO: 31 and the VL of J695 has the amino acid sequence of SEQ ID NO: 32 (these sequences are also shown in FIGS. 1A-1D, aligned with Joe9). Accordingly, in another aspect, the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. In preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27, and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28. In another preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. In yet another preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 32. In certain embodiments, the full length antibody comprises a heavy chain constant region, such as IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions and any allotypic variant therein as described in Kabat (, Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). Preferably, the antibody heavy chain constant region is an IgG1 heavy chain constant region. Alternatively, the antibody portion can be an Fab fragment, an F(ab′2) fragment or a single chain Fv fragment. Additional mutations in the preferred consensus sequences for CDR3, CDR2, and CDR1 of antibodies on the lineage from Joe 9 to J695, or from the lineage Y61 to J695, can be made to provide additional anti-IL-12 antibodies of the invention. Such methods of modification can be performed using standard molecular biology techniques, such as by PCR mutagenesis, targeting individual contact or hypermutation amino acid residues in the light chain and/or heavy chain CDRs-, followed by kinetic and functional analysis of the modified antibodies as described herein (e.g., neutralization assays described in Example 3, and by BIAcore analysis, as described in Example 5). Accordingly, in another aspect the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−6 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. In another aspect the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. An ordinarily skilled artisan will also appreciate that additional mutations to the CDR regions of an antibody of the invention, for example in Y61 or in J695, can be made to provide additional anti-IL-12 antibodies of the invention. Such methods of modification can be performed using standard molecular biology techniques, as described above. The functional and kinetic analysis of the modified antibodies can be performed as described in Example 3 and Example 5, respectively. Modifications of individual residues of Y61 that led to the identification of J695 are shown in FIGS. 2A-2H and are described in Example 2. Accordingly, in another aspect the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. In another aspect the invention features an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC50 of 1×10−9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position or a hypermutation position, wherein said mutant has a koff rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position or a hypermutation position, wherein said mutant has a Koff rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. In yet another embodiment, the invention provides isolated human antibodies, or antigen-binding portions thereof, that neutralize the activity of human IL-12, and at least one additional primate IL-12 selected from the group consisting of baboon IL-12, marmoset IL-12, chimpanzee IL-12, cynomolgus IL-12 and rhesus IL-12, but which do not neutralize the activity of the mouse IL-12. II Selection of Recombinant Human Antibodies Recombinant human antibodies of the invention can be isolated by screening of a recombinant combinatorial antibody library, preferably a scFv phage display library, prepared using human VL and VH cDNAs prepared from mRNA derived from human lymphocytes. Methodologies for preparing and screening such libraries are known in the art. In addition to commercially available kits for generating phage display libraries (e.g., the Pharmacia Recombinant Phage Antibody System, catalog no. 27-9400-01; and the Stratagene SurfZap™ phage display kit, catalog no. 240612), examples of methods and reagents particularly amenable for use in generating and screening antibody display libraries can be found in, for example, Kang et al. PCT Publication No. WO 92/18619; Winter et al. PCT Publication No. WO 92/20791; Breitling et al. PCT Publication No. WO 93/01288; McCafferty et al. PCT Publication No. WO 92/01047; Garrard et al. PCT Publication No. WO 92/09690; Fuchs et al. (1991) Bio/Technology 9:1370-1372; Hay et al. (1992) Hum Antibod Hybridomas 3:81-85; Huse et al. (1989) Science 246:1275-1281; McCafferty et al., Nature (1990) 348:552-554; Griffiths et al. (1993) EMBO J. 12:725-734; Hawkins et al. (1992) J Mol Biol 226:889-896; Clackson et al (1991) Nature 352:624-628; Gram et al. (1992) PNAS 89:3576-3580; Garrad et al. (1991) Bio/Technology 9:1373-1377; Hoogenboom et al. (1991) Nuc Acid Res 19:4133-4137; and Barbas et al. (1991) PNAS 88:7978-7982. The antibody libraries used in this method are preferably scFv libraries prepared from human VL and VH cDNAs. The scFv antibody libraries are preferably screened using recombinant human IL-12 as the antigen to select human heavy and light chain sequences having a binding activity toward IL-12. To select for antibodies specific for the p35 subunit of IL-12 or the p70 heterodimer, screening assays were performed in the presence of excess free p40 subunit. Subunit preferences can be determined, for example by, micro-Friguet titration, as described in Example 1. Once initial human VL and VH segments are selected, “mix and match” experiments, in which different pairs of the selected VL and VH segments are screened for IL-12 binding, are performed to select preferred VL/VH pair combinations (see Example 1). Additionally, to further improve the affinity and/or lower the off rate constant for hIL-12 binding, the VL and VH segments of the preferred VL/VH pair(s) can be randomly mutated, preferably within the CDR3 region of VH and/or VL, in a process analogous to the in vivo somatic mutation process responsible for affinity maturation of antibodies during a natural immune response. This in vitro affinity maturation can be accomplished by amplifying VH and VL regions using PCR primers complimentary to the VH CDR3 or VL CDR3, respectively, which primers have been “spiked” with a random mixture of the four nucleotide bases at certain positions such that the resultant PCR products encode VH and VL segments into which random mutations have been introduced into the VH and/or VL CDR3 regions. These randomly mutated VH and VL segments can be reselected and rescreened for binding to hIL-12 and sequences that exhibit high affinity and a low off rate for IL-12 binding can be selected. Table 2 (see Appendix A) shows antibodies that displayed altered binding specificity/affinity produced as a result of in vitro affinity maturation. Following selection, isolation and screening of an anti-hIL-12 antibody of the invention from a recombinant immunoglobulin display library, nucleic acid encoding the selected antibody can be recovered from the phage particle(s) (e.g., from the phage genome) and subcloned into other expression vectors by standard recombinant DNA techniques. If desired, the nucleic acid can be further manipulated to create other antibody forms of the invention (e.g., linked to nucleic acid encoding additional immunoglobulin domains, such as additional constant regions). To express a recombinant human antibody isolated by screening of a combinatorial library, the DNA encoding the antibody is cloned into a recombinant expression vector and introduced into a mammalian host cells, as described in further detail in Section IV below. Methods for selecting human IL-12 binding antibodies by phage display technology, and affinity maturation of selected antibodies by random or site-directed mutagenesis of CDR regions are described in further detail in Example 1. As described in Example 1, screening of human VL and VH cDNA libraries identified a series of anti-IL-12 antibodies, of which the Joe 9 antibody was selected for further development. A comparison of the heavy chain variable region of Joe 9 with the heavy chain germline sequences selected from the VBASE database, revealed that Joe 9 was similar to the COS-3 germline sequence. COS-3 belongs to the VH3 family of germline sequences. The VH3 family is part of the human VH germline repertoire which is grouped into seven families, VH1-VH7, based on nucleotide sequence homology (Tomlinson et al. (1992) J. Mol. Biol., 227, 776-798 and Cook et al. (1995) Immunology Today, 16, 237-242). The VH3 family contains the highest number of members and makes the largest contribution to the germline repertoire. For any given human VH3-germline antibody sequence, the amino acid sequence identity within the entire VH3 family is high (See e.g., Tomlinson et al. (1992) J. Mol. Biol., 227, 776-798 and Cook et al. (1995) Immunology Today, 16, 237-242). The range of amino acid sequence identity between any two germline VH sequences of the VH3 family varies from 69-98 residues out of approximately 100 VH residues, (i.e., 69-98% amino acid sequence homology between any two germline VH sequences). For most pairs of germline sequences there is at least 80 or more identical amino acid residues, (i.e., at least 80% amino acid sequence homology). The high degree of amino acid sequence homology between the VH3 family members results in certain amino acid residues being present at key sites in the CDR and framework regions of the VH chain. These amino acid residues confer structural features upon the CDRs. Studies of antibody structures have shown that CDR conformations can be grouped into families of canonical CDR structures based on the key amino acid residues that occupy certain positions in the CDR and framework regions. Consequently, there are similar local CDR conformations in different antibodies that have canonical structures with identical key amino acid residues (Chothia et al. (1987) J. Mol. Biol., 196, 901-917 and Chothia et al. (1989) Nature, 342, 877-883). Within the VH3 family there is a conservation of amino acid residue identity at the key sites for the CDR1 and CDR2 canonical structures (Chothia et al. (1992) J. Mol. Biol., 227, 799-817). The COS-3 germline VH gene, is a member of the VH3 family and is a variant of the 3-30 (DP-49) germline VH allele. COS-3, differs from Joe9 VH amino acid sequences at only 5 positions. The high degree of amino acid sequence homology between Joe9 VH and COS-3, and between Joe9 VH and the other VH3 family members also confers a high degree of CDR structural homology (Chothia et al. (1992) J. Mol. Biol., 227, 799-817; Chothia et al. (1987) J. Mol. Biol., 196, 901-917 and Chothia et al. (1989) Nature, 342, 877-883). The skilled artisan will appreciate that based on the high amino acid sequence and canonical structural similarity to Joe 9, other VH3 family members could also be used to generate antibodies that bind to human IL-12. This can be performed, for example, by selecting an appropriate VL by chain-shuffling techniques (Winter et al. (1994) Annual Rev. Immunol., 12, 433-55), or by the grafting of CDRs from a rodent or other human antibody including CDRs from antibodies of this invention onto a VH3 family framework. The human V lambda germline repertoire is grouped into 10 families based on nucleotide sequence homology (Williams et al. (1996) J. Mol. Biol., 264, 220-232). A comparison of the light chain variable region of Joe 9 with the light chain germline sequences selected from the VBASE database, revealed that Joe 9 was similar to the DPL8 lambda germline. The Joe9 VL differs from DPL8 sequence at only four framework positions, and is highly homologous to the framework sequences of the other Vλ1 family members. Based on the high amino acid sequence homology and canonical structural similarity to Joe 9, other Vλ1 family members may also be used to generate antibodies that bind to human IL-12. This can be performed, for example, by selecting an appropriate VH by chain-shuffling techniques (Winter et al. Supra, or by the grafting of CDRs from a rodent or other human antibody including CDRs from antibodies of this invention onto a V?1 family framework. The methods of the invention are intended to include recombinant antibodies that bind to hIL-12, comprising a heavy chain variable region derived from a member of the VH3 family of germline sequences, and a light chain variable region derived from a member of the Vλ1 family of germline sequences. Moreover, the skilled artisan will appreciate that any member of the VH3 family heavy chain sequence can be combined with any member of the Vλ1 family light chain sequence. Those skilled in the art will also appreciate that DNA sequence polymorphisms that lead to changes in the amino acid sequences of the germline may exist within a population (e.g., the human population). Such genetic polymorphism in the germline sequences may exist among individuals within a population due to natural allelic variation. Such natural allelic variations can typically result in 1-5% variance in the nucleotide sequence of the a gene. Any and all such nucleotide variations and resulting amino acid polymorphisms in germline sequences that are the result of natural allelic variation are intended to be within the scope of the invention. Accordingly, in one aspect, the invention features an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the VH3 germline family, wherein the heavy chain variable region has a mutation at a contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from a member of the Vλ1 germline family, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In a preferred embodiment, the isolated human antibody, or antigen binding has mutation in the heavy chain CDR3. In another preferred embodiment, the isolated human antibody, or antigen binding has mutation in the light chain CDR3. In another preferred embodiment, the isolated human antibody, or antigen binding has mutation in the heavy chain CDR2. In another preferred embodiment, the isolated human antibody, or antigen binding has mutation in the light chain CDR2. In another preferred embodiment, the isolated human antibody, or antigen binding has mutation in the heavy chain CDR1. In another preferred embodiment, the isolated human antibody, or antigen binding has mutation in the light chain CDR1. An ordinarily skilled artisan will appreciate that based on the high amino acid sequence similarity between members of the VH3 germline family, or between members of the light chain Vλ1 germline family, that mutations to the germlines sequences can provide additional antibodies that bind to human IL-12. Table 1 (see Appendix A) shows the germline sequences of the VH3 family members and demonstrates the significant sequence homology within the family members. Also shown in Table 1 are the germline sequences for Vλ1 family members. The heavy and light chain sequences of Joe 9 are provided as a comparison. Mutations to the germline sequences of VH3 or Vλ1 family members may be made, for example, at the same amino acid positions as those made in the antibodies of the invention (e.g. mutations in Joe 9). The modifications can be performed using standard molecular biology techniques, such as by PCR mutagenesis, targeting individual amino acid residues in the germline sequences, followed by kinetic and functional analysis of the modified antibodies as described herein (e.g., neutralization assays described in Example 3, and by BIAcore analysis, as described in Example 5). Accordingly, in one aspect, the invention features isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) has a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 595-667, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. b) has a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 669-675, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. An ordinarily skilled artisan will appreciate that based on the high amino acid sequence similarity between Joe 9 and COS-3 heavy chain germline sequence, and between Joe 9 and DPL8 lambda germline sequence, that other mutations to the CDR regions of these germlines sequences can provide additional antibodies that bind to human IL-12. Such methods of modification can be performed using standard molecular biology techniques as described above. Accordingly, in one aspect, the invention features isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising the COS-3 germline amino acid sequence, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising the DPL8 germline amino acid sequence, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. Due to certain amino acid residues occupying key sites in the CDR and framework regions in the light and heavy chain variable region, structural features are conferred at these regions. In particular, the CDR2 and CDR1 regions are subject to canonical structural classifications. Since there is a high degree of amino acids sequence homology between family members, these canonical features are present between family members. The skilled artisan will appreciate that modifications at the amino acid residues that confer these canonical structures would produce additional antibodies that bind to IL-12. The modifications can be performed using standard molecular biology techniques as described above. Accordingly, in another aspect, the invention features an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a koff rate constant of 0.1 s−1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC50 of 1×10−6M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the VH3 germline family, wherein the heavy chain variable region comprises a CDR2 that is structurally similar to CDR2s from other VH3 germline family members, and a CDR1 that is structurally similar to CDR1 s from other VH3 germline family members, and wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue; c) has a light chain variable region comprising an amino acid sequence selected from a member of the Vλ1 germline family, wherein the light chain variable region comprises a CDR2 that is structurally similar to CDR2s from other Vλ1 germline family members, and a CDR1 that is structurally similar to CDR1 s from other Vλ1 germline family members, and wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. Recombinant human antibodies of the invention have variable and constant regions which are homologous to human germline immunoglobulin sequences selected from the VBASE database. Mutations to the recombinant human antibodies (e.g., by random mutagenesis or PCR mutagenesis) result in amino acids that are not encoded by human germline immunoglobulin sequences. Also, libraries of recombinant antibodies which were derived from human donors will contain antibody sequences that differ from their corresponding germline sequences due to the normal process of somatic mutation that occurs during B-cell development. It should be noted that if the “germline” sequences obtained by PCR amplification encode amino acid differences in the framework regions from the true germline configuration (i.e., differences in the amplified sequence as compared to the true germline sequence), it may be desirable to change these amino acid differences back to the true germline sequences (i.e., “backmutation” of framework residues to the germline configuration). Thus, the present invention can optionally include a backmutation step. To do this, the amino acid sequences of heavy and light chain encoded by the germline (as found as example in VBASE database) are first compared to the mutated immunoglobulin heavy and light chain framework amino acid sequences to identify amino acid residues in the mutated immunoglobulin framework sequence that differ from the closest germline sequences. Then, the appropriate nucleotides of the mutated immunoglobulin sequence are mutated back to correspond to the germline sequence, using the genetic code to determine which nucleotide changes should be made. Mutagenesis of the mutated immunoglobulin framework sequence is carried out by standard methods, such as PCR-mediated mutagenesis (in which the mutated nucleotides are incorporated into the PCR primers such that the PCR product contains the mutations) or site-directed mutagenesis. The role of each amino acid identified as candidate for backmutation should be investigated for a direct or indirect role in antigen binding and any amino acid found after mutation to affect any desirable characteristic of the human antibody should not be included in the final human antibody; as an example, activity enhancing amino acids identified by the selective mutagenesis approach will not be subject to backmutation. Assays to determine the characteristics of the antibody resulting from mutagenesis can include ELISA, competitive ELISA, in vitro and in vivo neutralization assays and/or (see e.g. Example 3) immunohistochemistry with tissue sections from various sources (including human, primate and/or other species). To minimize the number of amino acids subject to backmutation those amino acid positions found to be different from the closest germline sequence but identical to the corresponding amino acid in a second germline sequence can remain, provided that the second germline sequence is identical and colinear to the sequence of the human antibody of the invention for at least 10, preferably 12 amino acids, on both sides of the amino acid in question. This would assure that any peptide epitope presented to the immune system by professional antigen presenting cells in a subject treated with the human antibody of the invention would not be foreign but identical to a self-antigen, i.e. the immunoglobulin encoded by that second germline sequence. Backmutation may occur at any stage of antibody optimization; preferably, backmutation occurs directly before or after the selective mutagenesis approach. More preferably, backmutation occurs directly before the selective mutagenesis approach. III. Modifications to Preferred Selective Mutagenesis Positions, Contact and/or Hypermutation Positions Typically, selection of antibodies with improved affinities can be carried out using phage display methods, as described in section II above. This can be accomplished by randomly mutating combinations of CDR residues and generating large libraries containing antibodies of different sequences. However, for these selection methods to work, the antibody-antigen reaction must tend to equilibrium to allow, over time, preferential binding of higher affinity antibodies to the antigen. Selection conditions that would allow equilibrium to be established could not be determined (presumably due to additional non-specific interactions between the antigen and phage particle) when phage display methods were used to improve the affinity of selected anti-IL-12 antibodies, upon attaining a certain level of affinity achieved (i.e., that of antibody Y61). Accordingly, antibodies with even higher affinities could not be selected by phage display methods. Thus, for at least certain antibodies or antigens, phage display methods are limiting in their ability to select antibodies with a highly improved binding specificity/affinity. Accordingly, a method termed Selective Mutagenesis Approach which does not require phage display affinity maturation of antibodies, was established to overcome this limitation and is provided by the invention. Although this Selective Mutagenesis Approach was developed to overcome limitations using the phage display system, it should be noted that this method can also be used with the phage display system. Moreover, the selective mutagenesis approach can be used to improve the activity of any antibody. To improve the activity (e.g., affinity or neutralizing activity) of an antibody, ideally one would like to mutate every CDR position in both the heavy and light chains to every other possible amino acid residue. However, since there are, on average, 70 CDR positions within an antibody, such an approach would be very time consuming and labor intensive. Accordingly, the method of the invention allows one to improve the activity of the antibody by mutating only certain selected residues within the heavy and/or light chain CDRs. Furthermore, the method of the invention allows improvement in activity of the antibody without affecting other desirable properties of the antibody. Determining which amino acid residues of an antibody variable region are in contact with an antigen cannot be accurately predicted based on primary sequence or their positions within the variable region. Nevertheless, alignments of sequences from antibodies with different specificities conducted by Kabat et al. have identified the CDRs as local regions within the variable regions which differ significantly among antibodies (Kabat et al. (1971) Ann. NY Acad, Sci. 190:382-393, Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242). Structural studies have shown that the antigen binding surface is formed by amino acid residues present in the CDRs. Other amino acid residues outside the CDR are also known to play structural roles or be directly involved in antigen binding. Therefore, for each antigen-antibody pair, amino acid residues within and outside of the CDRs may be important. The sequence alignment studies by Tomlison et al identified a number of positions in the heavy and light chain CDR1 and CDR2, and in a portion of the kappa chain CDR3 which are frequent sites of somatic mutation. (Tomlison et al (1996) J. Mol. Biol. 256: 813-817). In particular, positions H31, H31B, H33, H33B, H52B, H56, H58, L30, L31, L31A, L50, L53, L91, L92, L93 and L94 were identified as frequent sites for somatic mutation. However, this analysis excludes the important heavy chain CDR3 regions, and sections of the light chain CDR3 which are known to lie in the center of an antibody binding site, and potentially provide important interactions with an antigen. Furthermore, Tomlison et al. propose that somatic diversity alone does not necessarily predict a role of a specific amino acid in antigen binding, and suggest conserved amino acid residues that contact the antigen, and diverse amino acid residues which do not contact the antigen. This conclusion is further supported by mutational studies on the role of somatic mutations to antibody affinity (Sharon, (1990), PNAS, 87:4814-7). Nineteen somatic mutations in a high-affinity anti-p-azophenylarsonate (Ars) antibody were simultaneously replaced with their corresponding germline residues, generating a germline version of the anti-Ars antibody which had a two-hundred fold loss in activity. The full affinity of the anti-Ars antibody could be recovered by restoring only three of the nineteen somatic mutations, demonstrating that many somatic mutations may be permitted that do not contribute to antigen binding activity. The result can be explained in part by the nature of antibody diversity itself. Immature B-cells may produce initially low affinity antibodies that recognize a number of self or non-self antigens. Moreover, antibodies may undergo in the course of affinity maturation sequence variations that may cause self-reactivity. Hypermutation of such low affinity antibodies may serve to abolish self-reactivity (“negative selection”) and increase affinity for the foreign antigen. Therefore, the analysis of primary and structural data of a large number of antibodies does not provide a method of predicting either (1) the role of somatic hyper-mutation sites in the affinity maturation process versus the process of decreasing affinity towards unwanted antigens, or (2) how a given amino acid contributes to the properties of a specific antigen-antibody pair. Other attempts to address the role of specific amino acid residues in antigen recognition were made by analyzing a number of crystal structures of antigen-antibody complexes (MacCallum et al. (1996) J. Mol. Biol. 262: 732-745). The potential role of positions located within and outside the CDRs was indicated. Positions in CDRs involved in antigen binding in more than 10 of 26 analyzed structures included H31, H33, H50, H52, H53, H54, H56, H58, H95, H96, H97, H98 and H100 in the heavy chain and L30A, L32, L91, L92, L93, L94, L96 in the light chain. However, the authors noted that prediction of antigen contacts using these and other structural data may over and under predict contact positions, leading to the speculation that a different strategy may have to be applied to different antigens. Pini et al. describe randomizing multiple residues in antibody CDR sequences in a large phage display library to rapidly increase antibody affinity (Pini et al. (1998) J. Biol. Chem. 273: 21769-21776). However, the high affinity antibodies discussed by Pini et al. had mutations in a total of eight positions, and a reductionary analysis of which changes are absolutely required to improve affinity of the antibody becomes impractical because of the large number of possible combinations to be tested for the smallest number of amino acids required. Furthermore, randomizing multiple residues may not necessarily preserve other desired properties of the antibody. Desirable properties or characteristics of an antibody are art-recognized and include for example, preservation of non-cross reactivity, e.g., with other proteins or human tissues and preservation of antibody sequences that are close to human germline immunoglobulin sequences improvement of neutralization potency. Other desirable properties or characteristics include ability to preserve species cross reactivity, ability to preserve epitope specificity and ability to preserve high expression levels of protein in mammalian cells. The desirable properties or characteristics can be observed or measured using art-recognized techniques including but not limited to ELISA, competitive ELISA, in vitro and in vivo neutralization assays (see e.g. Example 3), immunohistochemistry with tissue sections from different sources including human, primate or other sources as the need may be, and studies to expression in mammalian cells using transient expression or stable expression. In addition, the method of Pini et al may introduce more changes than the minimal number actually required to improve affinity and may lead to the antibodies triggering anti-human-antibody (HAMA) formation in human subjects. Further, as discussed elsewhere, the phage display as demonstrated here, or other related method including ribosome display may not work appropriately upon reaching certain affinities between antibody and antigen and the conditions required to reach equilibrium may not be established in a reasonable time frame because of additional interactions including interactions with other phage or ribosome components and the antigen. The ordinarily skilled artisan may glean interesting scientific information on the origin of antibody diversity from the teachings of the references discussed above. The present invention, however, provides a method for increasing antibody affinity of a specific antigen-antibody pair while preserving other relevant features or desirable characteristics of the antibody. This is especially important when considering the desirability of imparting a multitude of different characteristics on a specific antibody including antigen binding. If the starting antibody has desirable properties or characteristics which need to be retained, a selective mutagenesis approach can be the best strategy for preserving these desirable properties while improving the activity of the antibody. For example, in the mutagenesis of Y61, the aim was to increase affinity for hIL-12, and to improve the neutralization potency of the antibody while preserving desired properties. Desired properties of Y61 included (1) preservation of non-cross reactivity with other proteins or human tissues, (2) preservation of fine epitope specificity, i.e. recognizing a p40 epitope preferably in the context of the p70 (p40/p35) heterodimer, thereby preventing binding interference from free soluble p40; and (3) generation of an antibody with heavy and light chain amino acid sequences that were as close as possible to their respective germline immunoglobulin sequences. In one embodiment, the method of the invention provides a selective mutagenesis approach as a strategy for preserving the desirable properties or characteristics of the antibody while improving the affinity and/or neutralization potency. The term “selective mutagenesis approach” is as defined above and includes a method of individually mutating selected amino acid residues. The amino acid residues to be mutated may first be selected from preferred selective mutagenesis positions, then from contact positions, and then from hypermutation positions. The individual selected position can be mutated to at least two other amino acid residue and the effect of the mutation both on the desired properties of the antibody, and improvement in antibody activity is determined. The Selective Mutagenesis approach comprises the steps of: selecting candidate positions in the order 1) preferred selective mutagenesis positions; 2) contact positions; 3) hypermutation positions and ranking the positions based on the location of the position within the heavy and light chain variable regions of an antibody (CDR3 preferred over CDR2 preferred over CDR1); individually mutating candidate preferred selective mutagenesis positions, hypermutation and/or contact positions in the order of ranking, to all possible other amino acid residues and analyzing the effect of the individual mutations on the activity of the antibody in order to determine activity enhancing amino acid residues; if necessary, making stepwise combinations of the individual activity enhancing amino acid residues and analyzing the effect of the various combinations on the activity of the antibodies; selecting mutant antibodies with activity enhancing amino acid residues and ranking the mutant antibodies based on the location and identity of the amino acid substitutions with regard to their immunogenic potential. Highest ranking is given to mutant antibodies that comprise an amino acid sequence which nearly identical to a variable region sequence that is described in a germline database, or has an amino acid sequence that is comparable to other human antibodies. Lower ranking is given to mutant antibodies containing an amino acid substitution that is rarely encountered in either germline sequences or the sequences of other human antibodies. The lowest ranking is given to mutant antibodies with an amino acid substitution that has not been encountered in a germline sequence or the sequence of another human antibody. As set forth above, mutant antibodies comprising at least one activity enhancing amino acid residue located in CDR3 is preferred over CDR2 which is preferred over CDR1. The CDRs of the heavy chain variable regions are preferred over those of the light chain variable region. The mutant antibodies can also be studied for improvement in activity, e.g when compared to their corresponding parental antibody. The improvement in activity of the mutant antibody can be determined for example, by neutralization assays, or binding specificity/affinity by surface plasmon resonance analysis (see Example 3). Preferably, the improvement in activity can be at least 2-20 fold higher than the parental antibody. The improvement in activity can be at least “x1” to “x2” fold higher than the parental antibody wherein “x1” and “x2” are integers between and including 2 to 20, including ranges within the state range, e.g. 2-15, e.g. 5-10. The mutant antibodies with the activity enhancing amino acid residue also can be studied to determine whether at least one other desirable property has been retained after mutation. For example, with anti-hIL-12 antibodies testing for, (1) preservation of non-cross reactivity with other proteins or human tissues, (2) preservation of epitope recognition, i.e. recognizing a p40 epitope preferably in the context of the p70 (p40/p35) heterodimer, thereby preventing binding interference from free soluble p40; and (3) generation of antibodies with heavy and light chain amino acid sequences that were as close as possible to their respective germline immunoglobulin sequences, and determining which would be least likely to elicit a human immune response based on the number of differences from the germline sequence. The same observations can be made on an antibody having more than one activity enhancing amino acid residues, e.g. at least two or at least three activity enhancing amino acid residues, to determine whether retention of the desirable property or characteristic has occurred. An example of the use of a “selective mutagenesis approach”, in the mutagenesis of Y61 is described below. The individual mutations H31S→E, L50→Y, or L94G→Y each improved neutralization activity of the antibody. However, when combination clones were tested, the activity of the combined clone H31S→E+L50→Y+L94G→Y was no better than L50→Y+L94G→Y (J695). Therefore, changing the germline amino acid residue Ser to Glu at position 31 of CDR1 was unnecessary for the improved activity of J695 over Y61. The selective mutagenesis approach therefore, identified the minimal number of changes that contributed to the final activity, thereby reducing the immunogenic potential of the final antibody and preserving other desired properties of the antibody. Isolated DNA encoding the VH and VL produced by the selected mutagenesis approach can be converted into full length antibody chain genes, to Fab fragment genes as to a scFV gene, as described in section IV. For expression of VH and VL regions produced by the selected mutagenesis approach, expression vectors encoding the heavy and light chain can be transfected into variety host cells as described in detail in section IV. Preferred host cells include either prokaryotic host cells, for example, E coli, or eukaryotic host cells, for example, yeast cells, e.g., S. cerevisae. Most preferred eukaryotic host cells are mammalian host cells, described in detail in section IV. The selective mutagenesis approach provides a method of producing antibodies with improved activities without prior affinity maturation of the antibody by other means. The selective mutagenesis approach provides a method of producing antibodies with improved affinities which have been subject to back mutations. The selective mutagenesis approach also provides a method of improving the activity of affinity matured antibodies. The skilled artisan will recognize that the selective mutagenesis approach can be used in standard antibody manipulation techniques known in the art. Examples include, but are not limited to, CDR grafted antibodies, chimeric antibodies, scFV fragments, Fab fragments of a full length antibodies and human antibodies from other sources, e.g., transgenic mice. Rapid large scale mutational analysis of antibodies include in vitro transcription and translation using ribosome display technology (see e.g., Hanes et al., (1997) Proc. Natl. Acad. Sci. 94: 4937-4942; Dall Acqua et al.,(1998) Curr. Opin. Struc. Biol. 8: 443-450; He et al., (1997) Nucleic Acid Res. 25: 5132-5134), and U.S. Pat. Nos. 5,643,768 and 5,658,754 issued to Kawasaki. The selective mutagenesis approach also provides a method of producing antibodies with improved activities that can be selected using ribosomal display techniques. In the methods of the invention, antibodies or antigen binding portions thereof are further modified by altering individual positions in the CDRs of the HCVR and/or LCVR. Although these modifications can be made in phage-displayed antibodies, the method is advantageous in that it can be performed with antibodies that are expressed in other types of host systems, such as bacterial, yeast or mammalian cell expression systems. The individual positions within the CDRs selected for modification are based on the positions being a contact and/or hypermutation position. Preferred contact positions and hypermutation positions as defined herein are shown in Table 3 (see Appendix A) and their modification in accordance with the method of the invention is described in detail in Example 2. Preferred contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. Preferred hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. More preferred amino acid residues (referred to as “preferred selective mutagenesis positions”) are both contact and hypermutation positions and are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. Particularly preferred contact positions are selected from the group consisting of L50 and L94. Preferred activity enhancing amino acid residues replace amino acid residues located at positions selected from the group consisting of of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94, and L96. More preferred activity enhancing amino acid residues replace amino acid residues located at positions H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. Particularly, preferred activity enhancing amino acid residues replace amino acid residues located at positions selected from the group consisting of L50 and L94. In general, the method of the invention involves selecting a particular preferred selective mutagenesis position, contact and/or hypermutation position within a CDR of the heavy or light chain of a parent antibody of interest, or antigen binding portion thereof, randomly mutagenizing that individual position (e.g., by genetic means using a mutagenic oligonucleotide to generate a “mini-library” of modified antibodies), or mutating a position to specific desired amino acids, to identify activity enhancing amino acid residues expressing, and purifying the modified antibodies (e.g., in a non-phage display host system), measuring the activity of the modified antibodies for antigen (e.g., by measuring Koff rates by BIAcore analysis), repeating these steps for other CDR positions, as necessary, and combining individual mutations shown to have improved activity and testing whether the combination(s) generate an antibody with even greater activity (e.g., affinity or neutralizing potency) than the parent antibody, or antigen-binding portion thereof. Accordingly, in one embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting in order a 1) preferred selective mutagenesis position, 2) contact position, or 3) hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) optionally, repeating steps a) through d) for at least one other preferred selective mutagenesis position, contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the selected antibody or antibodies have an improved activity without loss or with retention of at least one desirable characteristic or property of the parental antibody as described above. The desirable characteristic or property can be measured or observed by the ordinarily skilled artisan using art-recognized techniques. Preferred contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. Preferred hypermutation positions are selected from the group consisting of H30, H31, H[31 B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. More preferred preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93 and L94. Particularly preferred contact positions are selected from the group consisting of L50 and L94. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof, b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) optionally, repeating steps a) through d) for at least one other preferred selective mutagenesis position, contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof, and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferred contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. Preferred hypermutation positions are selected from the group consisting of H30, H31, H31 B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. More preferred preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93 and L94. Particularly preferred contact positions are selected from the group consisting of L50 and L94. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) optionally, repeating steps a) through d) for at least one other preferred selective mutagenesis position, contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, three individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the activity enhancing amino acid residue replaces amino acid residues located at positions selected from the group consisting of H30, H31, H[31 B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. Following mutagenesis of individual selected positions, mutated clones can be sequenced to identify which amino acid residues have been introduced into the selected position in each clone. A small number of clones (e.g., about 24) can be selected for sequencing, which statistically should yield 10−15 unique antibodies, whereas larger numbers of clones (e.g., greater than 60) can be sequenced to ensure that antibodies with every possible substitution at the selected position are identified. In one embodiment, contact and/or hypermutation positions within the CDR3 regions of the heavy and/or light chains are first selected for mutagenesis. However, for antibodies that have already been affinity matured in vitro by random mutagenesis of the CDR3 regions via phage display selection, it may be preferably to first select contact and/or hypermutation positions within CDR1 or CDR2 of the heavy and/or light chain. In a more preferred embodiment, preferred selective mutagenesis positions within the CDR3 regions of the heavy and/or light chains are first selected for mutagenesis. However, for antibodies that have already been affinity matured in vitro by random mutagenesis of the CDR3 regions via phage display selection, it may be preferably to first select preferred selective mutagenesis positions within CDR1 or CDR2 of the heavy and/or light chain. In another preferred embodiment, the optimization of a selected antibody by the selective mutagenesis approach is done sequentially as follows: preferred selective mutagenesis positions selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 are mutated first to at least 2 other amino acids each (preferably 5-14 other amino acids) and the resulting antibodies are characterized for increased affinity, neutralization potency (and possibly also for at least one other retained characteristic or property discussed elsewhere). If a mutation of a single preferred selective mutagenesis position does not increase the affinity or neutralization potency at all or sufficiently and if even the combination of multiple activity enhancing amino acids replacing amino acids in preferred selective mutagenesis positions does not result in an combination antibody which meets the target activity (including affinity and/or neutralization potency), additional amino acid residues will be selected for selective mutagenesis from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 are mutated to at least 2 other amino acids each (preferably 5-14 other amino acids) and the resulting antibodies are characterized for increased affinity, neutralization potency (and possibly also for at least one other retained characteristic or property discussed elsewhere). If a mutation of a single amino acid residue selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 does not increase the activity (including affinity and/or neutralization potency) at all or not sufficiently and if even the combination of multiple activity enhancing amino acids replacing amino acids in those positions does not result in an combination antibody which meets the targeted activity (including affinity and/or target neutralization potency), additional amino acid residues will be selected for selective mutagenesis from the group consisting of H33B, H52B, L31 A and are mutated to at least 2 other amino acids each (preferably 5-14 other amino acids) and the resulting antibodies are characterized for increased affinity, neutralization potency (and possibly also for at least one other retained characteristic or property discussed elsewhere). It should be understood that the sequential selective mutagenesis approach may end at any of the steps outline above as soon as an antibody with the desired activity (including affinity and neutralization potency) has been identified. If mutagenesis of the preselected positions has identified activity enhancing amino acids residues but the combination antibody still do not meet the targets set for activity (including affinity and neutralization potency) and/or if the identified activity enhancing amino acids also affect other desired characteristics and are therefore not acceptable, the remaining CDR residues may be subjected to mutagenesis (see section IV). The method of the invention can be used to improve activity of an antibody, or antigen binding portion thereof, to reach a predetermined target activity (e.g. a predetermined affinity and/or neutralization potency, and/or a desired property or characteristic). Accordingly, the invention provides a method of improving the activity of an antibody, or antigen-binding portion thereof, to attain a predetermined target activity, comprising: a) providing a parent antibody a antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position selected from group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. c) individually mutating the selected preferred selective mutagenesis position to at least two other amino acid residues to hereby create a first panel of mutated antibodies, or antigen binding portions thereof; d) evaluating the activity of the first panel of mutated antibodies, or antigen binding portions thereof to determined if mutation of a single selective mutagenesis position produces an antibody or antigen binding portion thereof with the predetermined target activity or a partial target activity; e) combining in a stepwise fashion, in the parent antibody, or antigen binding portion thereof, individual mutations shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof. f) evaluating the activity of the combination antibodies, or antigen binding portions thereof to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity. g) if steps d) or f) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result an antibody with only a partial activity, additional amino acid residues selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 are mutated to at least two other amino acid residues to thereby create a second panel of mutated antibodies or antigen-binding portions thereof, h) evaluating the activity of the second panel of mutated antibodies or antigen binding portions thereof, to determined if mutation of a single amino acid residue selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 results an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; i) combining in stepwise fashion in the parent antibody, or antigen-binding portion thereof, individual mutations of step g) shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof; j) evaluating the activity of the combination antibodies or antigen binding portions thereof, to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity; k) if steps h) or j) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result in an antibody with only a partial activity, additional amino acid residues selected from the group consisting of H33B, H52B and L31 A are mutated to at least two other amino acid residues to thereby create a third panel of mutated antibodies or antigen binding portions thereof, l) evaluating the activity of the third panel of mutated antibodies or antigen binding portions thereof, to determine if a mutation of a single amino acid residue selected from the group consisting of H33B, H52B and L31 A resulted in an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; m) combining in a stepwise fashion in the parent antibody, or antigen binding portion thereof, individual mutation of step k) shown to have an improved activity, to form combination antibodies, or antigen binding portions, thereof; n) evaluating the activity of the combination antibodies or antigen-binding portions thereof, to determine if the combination antibodies, or antigen binding portions thereof have the predetermined target activity to thereby produce an antibody or antigen binding portion thereof with a predetermined target activity. A number of mutagenesis methods can be used, including PCR assembly, Kunkel (dut-ung-) and thiophosphate (Amersham Sculptor kit) oligonucleotide-directed mutagenesis. A wide variety of host expression systems can be used to express the mutated antibodies, including bacterial, yeast, baculoviral and mammalian expression systems (as well as phage display expression systems). An example of a suitable bacterial expression vector is pUC119(Sfi). Other antibody expression systems are known in the art and/or are described below in section IV. The modified antibodies, or antigen binding portions thereof, produced by the method of the invention can be identified without the reliance on phage display methods for selection. Accordingly, the method of the invention is particularly advantageous for improving the activity of a recombinant parent antibody or antigen-binding portion thereof, that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in the phage-display system. Accordingly, in another embodiment, the invention provides a method for improving the affinity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof, that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) optionally repeating steps b) through d) for at least one other preferred selective mutagenesis position, contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferred contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. Preferred hypermutation positions are selected from the group consisting of H30, H31, H[31 B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. More preferred preferred selective mutagenesis positions are selected from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93 and L94. Particularly preferred contact positions are selected from the group consisting of L50 and L94. With available methods it is not possible or it is extremely laborious to derive an antibody with increased binding affinity and neutralization potency while retaining other properties or characteristics of the antibodies as discussed above. The method of this invention, however, can readily identify such antibodies. The antibodies subjected to the method of this invention can come from any source. Therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expressing said panel in an appropriate expression system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristics, wherein the property or characteristic is one that needs to be retained in the antibody; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. If therefore, the affinity of an antibody for a specific antigen should be improved, but where the phage display (or related system including ribosome display) method is no longer applicable, and other desirable properties or characteristics should be retained, the method of the invention can be used. Accordingly, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) optionally, repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least one retained property or characteristic, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, until an antibody, or antigen-binding portion thereof, with an improved activity and at, least one retained other property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis positions, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) optionally, repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least on retained other characteristic, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group, consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. IV. Modifications of Other CDR residues Ultimately, all CDR residues in a given antibody-antigen pair identified by any means to be required as activity enhancing amino acid residues and/or required directly or indirectly for binding to the antigen and/or for retaining other desirable properties or characteristics of the antibody. Such CDR residues are referred to as “preferred selective mutagenesis positions”. It should be noted that in specific circumstances that preferred selective mutagenesis residues can be identified also by other means including co-crystallization of antibody and antigen and molecular modeling. If the preferred attempts to identify activity enhancing amino acids focussing on the preferred selective mutagenesis positions, contact or hypermutation positions described above are exhausted, or if additional improvements are required, the remaining CDR residues may be modified as described below. It should be understood that the antibody could already be modified in any one or more contact or hypermutation positions according to the embodiments discussed above but may require further improvements. Therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position e.g., to at least two other amino acid residues to thereby create a mutated antibody or a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the mutated antibody or the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the mutated antibody or the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence If mutagenesis of a single residue is not sufficient other residues can be included; therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31. L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. If the preferred attempts to identify activity enhancing amino acids focussing on the contact or hypermutation positions described above are exhausted, or if additional improvements are required, and the antibody in question can not further be optimized by mutagenesis and phage display (or related ribosome display) methods the remaining CDR residues may be modified as described below. It should be understood that the antibody could already be modified in any one or more preferred selective mutagenesis position, contact or hypermutation positions according to the embodiments discussed above but may require further improvements. Therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic, until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. If a single mutagenesis is not sufficient to increase the affinity of the antibody other residues may be included in the mutagenesis. Therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity and other property or characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence The preferred attempts to identify activity enhancing amino acids focussing on the preferred selective mutagenesis positions, contact or hypermutation positions described may be exhausted, or additional improvements may be required, and it is important to retain other properties or characteristics of the antibody. Therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, without affecting other characteristics, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity and retained other property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence If mutagenesis of a single residue is not sufficient other residues can be included; therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e.) evaluating the panel of mutated antibodies or antigen-binding portions thereof, relative to the parent antibody or antigen-portion thereof, for changes in at least one other characteristic or property; e) repeating steps b) through e) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not affecting at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and the retention of at least one other property or characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained other property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Mutagenesis of the preferred selective mutagenesis position, contact and hypermutation residues may not have increased the affinity of the antibody sufficiently, and mutagenesis and the phage display method (or related ribosome display method) may no longer be useful and at least one other characteristic or property of the antibody should be retained. Therefore, in another embodiment the invention provides a method to improve the affinity of an antibody or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence If mutagenesis of a single residue is not sufficient other residues can be included; therefore, in another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity and retention of at least one other property or characteristic of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not to affect at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and retention of at least one property or characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one other retained characteristic or property, relative to the parent antibody, or antigen-binding portion thereof, is obtained. V. Expression of Antibodies An antibody, or antibody portion, of the invention can be prepared by recombinant expression of immunoglobulin light and heavy chain genes in a host cell. To express an antibody recombinantly, a host cell is transfected with one or more recombinant expression vectors carrying DNA fragments encoding the immunoglobulin light and heavy chains of the antibody such that the light and heavy chains are expressed in the host cell and, preferably, secreted into the medium in which the host cells are cultured, from which medium the antibodies can be recovered. Standard recombinant DNA methodologies are used to obtain antibody heavy and light chain genes, incorporate these genes into recombinant expression vectors and introduce the vectors into host cells, such as those described in Sambrook, Fritsch and Maniatis (eds), Molecular Cloning; A Laboratory Manual, Second Edition, Cold Spring Harbor, N.Y., (1989), Ausubel, F. M. et al. (eds.) Current Protocols in Molecular Biology, Greene Publishing Associates, (1989) and in U.S. Pat. No. 4,816,397 by Boss et al. To obtain a DNA fragment encoding the heavy chain variable region of Joe 9 wt or a Joe 9 wt-related antibody, antibodies specific for human IL-12 were screened from human libraries and mutated, as described in section II. Once DNA fragments encoding Joe 9 wt or Joe 9 wt-related VH and VL segments are obtained, mutagenesis of these sequences is carried out by standard methods, such as PCR site directed mutagenesis (PCR-mediated mutagenesis in which the mutated nucleotides are incorporated into the PCR primers such that the PCR product contains the mutations) or other site-directed mutagenesis methods. Human IL-12 antibodies that displayed a level of activity and binding specificity/affinity that was desirable, for example J695, were further manipulated by standard recombinant DNA techniques, for example to convert the variable region genes to full-length antibody chain genes, to Fab fragment genes or to a scFv gene. In these manipulations, a VL- or VH-encoding DNA fragment is operatively linked to another DNA fragment encoding another protein, such as an antibody constant region or a flexible linker. The term “operatively linked”, as used in this context, is intended to mean that the two DNA fragments are joined such that the amino acid sequences encoded by the two DNA fragments remain in-frame. The isolated DNA encoding the VH region can be converted to a full-length heavy chain gene by operatively linking the VH-encoding DNA to another DNA molecule encoding heavy chain constant regions (CH1, CH2 and CH3). The sequences of human heavy chain constant region genes are known in the art (see e.g., Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242) and DNA fragments encompassing these regions can be obtained by standard PCR amplification. The heavy chain constant region can be an IgG 1, IgG2, IgG3, IgG4, IgA, IgE, IgM or IgD constant region and any allotypic variant therein as described in Kabat (, Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242), but most preferably is an IgG1 or IgG4 constant region. For a Fab fragment heavy chain gene, the VH-encoding DNA can be operatively linked to another DNA molecule encoding only the heavy chain CH1 constant region. The isolated DNA encoding the VL region can be converted to a full-length light chain gene (as well as a Fab light chain gene) by operatively linking the VL-encoding DNA to another DNA molecule encoding the light chain constant region, CL. The sequences of human light chain constant region genes are known in the art (see e.g., Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242) and DNA fragments encompassing these regions can be obtained by standard PCR amplification. The light chain constant region can be a kappa or lambda constant region, but most preferably is a lambda constant region. To create a scFv gene, the VH— and VL-encoding DNA fragments are operatively linked to another fragment encoding a flexible linker, e.g., encoding the amino acid sequence (Gly4-Ser)3, such that the VH and VL sequences can be expressed as a contiguous single-chain protein, with the VL and VH regions joined by the flexible linker (see e.g., Bird et al. (1988) Science 242:423-426; Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883; McCafferty et al., Nature (1990) 348:552-554). To express the antibodies, or antibody portions of the invention, DNAs encoding partial or full-length light and heavy chains, obtained as described above, are inserted into expression vectors such that the genes are operatively linked to transcriptional and translational control sequences. In this context, the term “operatively linked” is intended to mean that an antibody gene is ligated into a vector such that transcriptional and translational control sequences within the vector serve their intended function of regulating the transcription and translation of the antibody gene. The expression vector and expression control sequences are chosen to be compatible with the expression host cell used. The antibody light chain gene and the antibody heavy chain gene can be inserted into separate vector or, more typically, both genes are inserted into the same expression vector. The antibody genes are inserted into the expression vector by standard methods (e.g., ligation of complementary restriction sites on the antibody gene fragment and vector, or blunt end ligation if no restriction sites are present). Prior to insertion of the J695 or J695-related light or heavy chain sequences, the expression vector may already carry antibody constant region sequences. For example, one approach to converting the J695 or J695-related VH and VL sequences to full-length antibody genes is to insert them into expression vectors already encoding heavy chain constant and light chain constant regions, respectively, such that the VH segment is operatively linked to the CH segment(s) within the vector and the VL segment is operatively linked to the CL segment within the vector. Additionally or alternatively, the recombinant expression vector can encode a signal peptide that facilitates secretion of the antibody chain from a host cell. The antibody chain gene can be cloned into the vector such that the signal peptide is linked in-frame to the amino terminus of the antibody chain gene. The signal peptide can be an immunoglobulin signal peptide or a heterologous signal peptide (i.e., a signal peptide from a non-immunoglobulin protein). In addition to the antibody chain genes, the recombinant expression vectors of the invention carry regulatory sequences that control the expression of the antibody chain genes in a host cell. The term “regulatory sequence” is intended to include promoters, enhancers and other expression control elements (e.g., polyadenylation signals) that control the transcription or translation of the antibody chain genes. Such regulatory sequences are described, for example, in Goeddel; Gene Expression Technology: Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990). It will be appreciated by those skilled in the art that the design of the expression vector, including the selection of regulatory sequences may depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, etc. Preferred regulatory sequences for mammalian host cell expression include viral elements that direct high levels of protein expression in mammalian cells, such as promoters and/or enhancers derived from cytomegalovirus (CMV) (such as the CMV promoter/enhancer), Simian Virus 40 (SV40) (such as the SV40 promoter/enhancer), adenovirus, (e.g., the adenovirus major late promoter (AdMLP)) and polyoma. For further description of viral regulatory elements, and sequences thereof, see e.g., U.S. Pat. No. 5,168,062 by Stinski, U.S. Pat. No. 4,510,245 by Bell et al. and U.S. Pat. No. 4,968,615 by Schaffner et al., U.S. Pat. No. 5,464,758 by Bujard et al. and U.S. Pat. No. 5,654,168 by Bujard et al. In addition to the antibody chain genes and regulatory sequences, the recombinant expression vectors of the invention may carry additional sequences, such as sequences that regulate replication of the vector in host cells (e.g., origins of replication) and selectable marker genes. The selectable marker gene facilitates selection of host cells into which the vector has been introduced (see e.g., U.S. Pat. Nos. 4,399,216, 4,634,665 and 5,179,017, all by Axel et al.). For example, typically the selectable marker gene confers resistance to drugs, such as G418, hygromycin or methotrexate, on a host cell into which the vector has been introduced. Preferred selectable marker genes include the dihydrofolate reductase (DHFR) gene (for use in dhfr host cells with methotrexate selection/amplification) and the neo gene (for G418 selection). For expression of the light and heavy chains, the expression vector(s) encoding the heavy and light chains is transfected into a host cell by standard techniques. The various forms of the term “transfection” are intended to encompass a wide variety of techniques commonly used for the introduction of exogenous DNA into a prokaryotic or eukaryotic host cell, e.g., electroporation, calcium-phosphate precipitation, DEAE-dextran transfection and the like. Although it is theoretically possible to express the antibodies of the invention in either prokaryotic or eukaryotic host cells, expression of antibodies in eukaryotic cells, and most preferably mammalian host cells, is the most preferred because such eukaryotic cells, and in particular mammalian cells, are more likely than prokaryotic cells to assemble and secrete a properly folded and immunologically active antibody. Preferred mammalian host cells for expressing the recombinant antibodies of the invention include Chinese Hamster Ovary (CHO cells) (including dhfr-CHO cells, described in Urlaub and Chasin, (1980) Proc. Natl. Acad. Sci. USA 77:4216-4220, used with a DHFR selectable marker, e.g, as described in R. J. Kaufman and P. A. Sharp (1982) Mol. Biol. 159:601-621), NS0 myeloma cells, COS cells and SP2 cells. When recombinant expression vectors encoding antibody genes are introduced into mammalian host cells, the antibodies are produced by culturing the host cells for a period of time sufficient to allow for expression of the antibody in the host cells or, more preferably, secretion of the antibody into the culture medium in which the host cells are grown. Antibodies can be recovered from the culture medium using standard protein purification methods. Host cells can also be used to produce portions of intact antibodies, such as Fab fragments or scFv molecules. It will be understood that variations on the above procedure are within the scope of the present invention. For example, it may be desirable to transfect a host cell with DNA encoding either the light chain or the heavy chain (but not both) of an antibody of this invention. Recombinant DNA technology may also be used to remove some or all of the DNA encoding either or both of the light and heavy chains that is not necessary for binding to hIL-12 The molecules expressed from such truncated DNA molecules are also encompassed by the antibodies of the invention. In addition, bifunctional antibodies may be produced in which one heavy and one light chain are an antibody of the invention and the other heavy and light chain are specific for an antigen other than hIL-12 by crosslinking an antibody of the invention to a second antibody by standard chemical crosslinking methods. In a preferred system for recombinant expression of an antibody, or antigen-binding portion thereof, of the invention, a recombinant expression vector encoding both the antibody heavy chain and the antibody light chain is introduced into dhfr-CHO cells by calcium phosphate-mediated transfection. Within the recombinant expression vector, the antibody heavy and light chain genes are each operatively linked to enhancer/promoter regulatory elements (e.g., derived from SV40, CMV, adenovirus and the like, such as a CMV enhancer/AdMLP promoter regulatory element or an SV40 enhancer/AdMLP promoter regulatory element) to drive high levels of transcription of the genes. The recombinant expression vector also carries a DHFR gene, which allows for selection of CHO cells that have been transfected with the vector using methotrexate selection/amplification. The selected transformant host cells are culture to allow for expression of the antibody heavy and light chains and intact antibody is recovered from the culture medium. Standard molecular biology techniques are used to prepare the recombinant expression vector, transfect the host cells, select for transformants, culture the host cells and recover the antibody from the culture medium. Antibodies or antigen-binding portions thereof of the invention can be expressed in an animal (e.g., a mouse) that is transgenic for human immunoglobulin genes (see e.g., Taylor, L. D. et al. (1992) Nucl. Acids Res. 20: 6287-6295). Plant cells can also be modified to create transgenic plants that express the antibody or antigen binding portion thereof, of the invention. In view of the foregoing, another aspect of the invention pertains to nucleic acid, vector and host cell compositions that can be used for recombinant expression of the antibodies and antibody portions of the invention. Preferably, the invention features isolated nucleic acids that encode CDRs of J695, or the full heavy and/or light chain variable region of J695. Accordingly, in one embodiment, the invention features an isolated nucleic acid encoding an antibody heavy chain variable region that encodes the J695 heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25. Preferably, the nucleic acid encoding the antibody heavy chain variable region further encodes a J695 heavy chain CDR2 which comprises the amino acid sequence of SEQ ID NO: 27. More preferably, the nucleic acid encoding the antibody heavy chain variable region further encodes a J695 heavy chain CDR1 which comprises the amino acid sequence of SEQ ID NO: 29. Even more preferably, the isolated nucleic acid encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31 (the full VH region of J695). In other embodiments, the invention features an isolated nucleic acid encoding an antibody light chain variable region that encodes the J695 light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. Preferably, the nucleic acid encoding the antibody light chain variable region further encodes a J695 light chain CDR2 which comprises the amino acid sequence of SEQ ID NO: 28. More preferably, the nucleic acid encoding the antibody light chain variable region further encodes a J695 light chain CDR1 which comprises the amino acid sequence of SEQ ID NO: 30. Even more preferably, the isolated nucleic acid encodes an antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 32 (the full VL region of J695). The invention also provides recombinant expression vectors encoding both an antibody heavy chain and an antibody light chain. For example, in one embodiment, the invention provides a recombinant expression vector encoding: a) an antibody heavy chain having a variable region comprising the amino acid sequence of SEQ ID NO: 31; and b) an antibody light chain having a variable region comprising the amino acid sequence of SEQ ID NO: 32. The invention also provides host cells into which one or more of the recombinant expression vectors of the invention have been introduced. Preferably, the host cell is a mammalian host cell, more preferably the host cell is a CHO cell, an NS0 cell or a COS cell. Still further the invention provides a method of synthesizing a recombinant human antibody of the invention by culturing a host cell of the invention in a suitable culture medium until a recombinant human antibody of the invention is synthesized. The method can further comprise isolating the recombinant human antibody from the culture medium. VI. Pharmaceutical Compositions and Pharmaceutical Administration The antibodies and antibody-portions of the invention can be incorporated into pharmaceutical compositions suitable for administration to a subject. Typically, the pharmaceutical composition comprises an antibody or antibody portion of the invention and a pharmaceutically acceptable carrier. As used herein, “pharmaceutically acceptable carrier” includes any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like that are physiologically compatible. Examples of pharmaceutically acceptable carriers include one or more of water, saline, phosphate buffered saline, dextrose, glycerol, ethanol and the like, as well as combinations thereof. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols such as mannitol, sorbitol, or sodium chloride in the composition. Pharmaceutically acceptable carriers may further comprise minor amounts of auxiliary substances such as wetting or emulsifying agents, preservatives or buffers, which enhance the shelf life or effectiveness of the antibody or antibody portion. The antibodies and antibody-portions of the invention can be incorporated into a pharmaceutical composition suitable for parenteral administration. Preferably, the antibody or antibody-portions will be prepared as an injectable solution containing 0.1-250 mg/ml antibody. The injectable solution can be composed of either a liquid or lyophilized dosage form in a flint or amber vial, ampule or pre-filled syringe. The buffer can be L-histidine (1-50 mM), optimally 5-10 mM, at pH 5.0 to 7.0 (optimally pH 6.0). Other suitable buffers include but are not limited to, sodium succinate, sodium citrate, sodium phosphate or potassium phosphate. Sodium chloride can be used to modify the toxicity of the solution at a concentration of 0-300 mM (optimally 150 mM for a liquid dosage form). Cryoprotectants can be included for a lyophilized dosage form, principally 0-10% sucrose (optimally 0.5-1.0%). Other suitable cryoprotectants include trenhalose and lactose. Bulking agents can be included for a lyophilized dosage form, principally 1-10% mannitol (optimally 2-4%). Stabilizers can be used in both liquid and lyophilized dosage forms, principally 1-50 mM L-Methionine (optimally 5-10 mM). Other suitable bulking agents include glycine, arginine, can be included as 0-0.05% polysorbate-80 (optimally 0.005-0.01%). Additional surfactants include but are not limited to polysorbate 20 and BRIJ surfactants. In a preferred embodiment, the pharmaceutical composition includes the antibody at a dosage of about 0.01 mg/kg-10 mg/kg. More preferred dosages of the antibody include 1 mg/kg administered every other week, or 0.3 mg/kg administered weekly. The compositions of this invention may be in a variety of forms. These include, for example, liquid, semi-solid and solid dosage forms, such as liquid solutions (e.g., injectable and infusible solutions), dispersions or suspensions, tablets, pills, powders, liposomes and suppositories. The preferred form depends on the intended mode of administration and therapeutic application. Typical preferred compositions are in the form of injectable or infusible solutions, such as compositions similar to those used for passive immunization of humans with other antibodies. The preferred mode of administration is parenteral (e.g., intravenous, subcutaneous, intraperitoneal, intramuscular). In a preferred embodiment, the antibody is administered by intravenous infusion or injection. In another preferred embodiment, the antibody is administered by intramuscular or subcutaneous injection. Therapeutic compositions typically must be sterile and stable under the conditions of manufacture and storage. The composition can be formulated as a solution, microemulsion, dispersion, liposome, or other ordered structure suitable to high drug concentration. Sterile injectable solutions can be prepared by incorporating the active compound (i.e., antibody or antibody portion) in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the active compound into a sterile vehicle that contains a basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile, lyophilized powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and spray-drying that yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof. The proper fluidity of a solution can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prolonged absorption of injectable compositions can be brought about by including in the composition an agent that delays absorption, for example, monostearate salts and gelatin. The antibodies and antibody-portions of the present invention can be administered by a variety of methods known in the art, although for many therapeutic applications, the preferred route/mode of administration is subcutaneous injection, intravenous injection or infusion. As will be appreciated by the skilled artisan, the route and/or mode of administration will vary depending upon the desired results. In certain embodiments, the active compound may be prepared with a carrier that will protect the compound against rapid release, such as a controlled release formulation, including implants, transdermal patches, and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Many methods for the preparation of such formulations are patented or generally known to those skilled in the art. See, e.g., Sustained and Controlled Release Drug Delivery Systems, J. R. Robinson, ed., Marcel Dekker, Inc., New York, 1978. In certain embodiments, an antibody or antibody portion of the invention may be orally administered, for example, with an inert diluent or an assimilable edible carrier. The compound (and other ingredients, if desired) may also be enclosed in a hard or soft shell gelatin capsule, compressed into tablets, or incorporated directly into the subject's diet. For oral therapeutic administration, the compounds may be incorporated with excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. To administer a compound of the invention by other than parenteral administration, it may be necessary to coat the compound with, or co-administer the compound with, a material to prevent its inactivation. Supplementary active compounds can also be incorporated into the compositions. In certain embodiments, an antibody or antibody portion of the invention is coformulated with and/or coadministered with one or more additional therapeutic agents that are useful for treating disorders in which IL-12 activity is detrimental. For example, an anti-hIL-12 antibody or antibody portion of the invention may be coformulated and/or coadministered with one or more additional antibodies that bind other targets (e.g., antibodies that bind other cytokines or that bind cell surface molecules). Furthermore, one or more antibodies of the invention may be used in combination with two or more of the foregoing therapeutic agents. Such combination therapies may advantageously utilize lower dosages of the administered therapeutic agents, thus avoiding possible toxicities or complications associated with the various monotherapies. It will be appreciated by the skilled practitioner that when the antibodies of the invention are used as part of a combination therapy, a lower dosage of antibody may be desirable than when the antibody alone is administered to a subject (e.g., a synergistic therapeutic effect may be achieved through the use of combination therapy which, in turn, permits use of a lower dose of the antibody to achieve the desired therapuetic effect). Interleukin 12 plays a critical role in the pathology associated with a variety of diseases involving immune and inflammatory elements. These diseases include, but are not limited to, rheumatoid arthritis, osteoarthritis, juvenile chronic arthritis, Lyme arthritis, psoriatic arthritis, reactive arthritis, spondyloarthropathy, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, inflammatory bowel disease, insulin dependent diabetes mellitus, thyroiditis, asthma, allergic diseases, psoriasis, dermatitis scleroderma, atopic dermatitis, graft versus host disease, organ transplant rejection, acute or chronic immune disease associated with organ transplantation, sarcoidosis, atherosclerosis, disseminated intravascular coagulation, Kawasaki's disease, Grave's disease, nephrotic syndrome, chronic fatigue syndrome, Wegener's granulomatosis, Henoch-Schoenlein purpurea, microscopic vasculitis of the kidneys, chronic active hepatitis, uveitis, septic shock, toxic shock syndrome, sepsis syndrome, cachexia, infectious diseases, parasitic diseases, acquired immunodeficiency syndrome, acute transverse myelitis, Huntington's chorea, Parkinson's disease, Alzheimer's disease, stroke, primary biliary cirrhosis, hemolytic anemia, malignancies, heart failure, myocardial infarction, Addison's disease, sporadic, polyglandular deficiency type I and polyglandular deficiency type II, Schmidt's syndrome, adult (acute) respiratory distress syndrome, alopecia, alopecia greata, seronegative arthopathy, arthropathy, Reiter's disease, psoriatic arthropathy, ulcerative colitic arthropathy, enteropathic synovitis, chlamydia, yersinia and salmonella associated arthropathy, spondyloarthopathy, atheromatous disease/arteriosclerosis, atopic allergy, autoimmune bullous disease, pemphigus vulgaris, pemphigus foliaceus, pemphigoid, linear IgA disease, autoimmune haemolytic anaemia, Coombs positive haemolytic anaemia, acquired pernicious anaemia, juvenile pernicious anaemia, myalgic encephalitis/Royal Free Disease, chronic mucocutaneous candidiasis, giant cell arteritis, primary sclerosing hepatitis, cryptogenic autoimmune hepatitis, Acquired Immunodeficiency Disease Syndrome, Acquired Immunodeficiency Related Diseases, Hepatitis C, common varied immunodeficiency (common variable hypogammaglobulinaemia), dilated cardiomyopathy, female infertility, ovarian failure, premature ovarian failure, fibrotic lung disease, cryptogenic fibrosing alveolitis, post-inflammatory interstitial lung disease, interstitial pneumonitis, connective tissue disease associated interstitial lung disease, mixed connective tissue disease associated lung disease, systemic sclerosis associated interstitial lung disease, rheumatoid arthritis associated interstitial lung disease, systemic lupus erythematosus associated lung disease, dermatomyositis/polymyositis associated lung disease, Sjögren's disease associated lung disease, ankylosing spondylitis associated lung disease, vasculitic diffuse lung disease, haemosiderosis associated lung disease, drug-induced interstitial lung disease, radiation fibrosis, bronchiolitis obliterans, chronic eosinophilic pneumonia, lymphocytic infiltrative lung disease, postinfectious interstitial lung disease, gouty arthritis, autoimmune hepatitis, type-I autoimmune hepatitis (classical autoimmune or lupoid hepatitis), type-2 autoimmune hepatitis (anti-LKM antibody hepatitis), autoimmune mediated hypoglycemia, type B insulin resistance with acanthosis nigricans, hypoparathyroidism, acute immune disease associated with organ transplantation, chronic immune disease associated with organ transplantation, osteoarthrosis, primary sclerosing cholangitis, idiopathic leucopenia, autoimmune neutropenia, renal disease NOS, glomerulonephritides, microscopic vasulitis of the kidneys, lyme disease, discoid lupus erythematosus, male infertility idiopathic or NOS, sperm autoimmunity, multiple sclerosis (all subtypes), insulin-dependent diabetes mellitus, sympathetic ophthalmia, pulmonary hypertension secondary to connective tissue disease, Goodpasture's syndrome, pulmonary manifestation of polyarteritis nodosa, acute rheumatic fever, rheumatoid spondylitis, Still's disease, systemic sclerosis, Takayasu's disease/arteritis, autoimmune thrombocytopenia, idiopathic thrombocytopenia, autoimmune thyroid disease, hyperthyroidism, goitrous autoimmune hypothyroidism (Hashimoto's disease), atrophic autoimmune hypothyroidism, primary myxoedema, phacogenic uveitis, primary vasculitis and vitiligo. The human antibodies, and antibody portions of the invention can be used to treat autoimmune diseases, in particular those associated with inflammation, including, rheumatoid spondylitis, allergy, autoimmune diabetes, autoimmune uveitis. Preferably, the antibodies of the invention or antigen-binding portions thereof, are used to treat rheumatoid arthritis, Crohn's disease, multiple sclerosis, insulin dependent diabetes mellitus and psoriasis, as described in more detail in section VII. A human antibody, or antibody portion, of the invention also can be administered with one or more additional therapeutic agents useful in the treatment of autoimmune and inflammatory diseases. Antibodies of the invention, or antigen binding portions thereof can be used alone or in combination to treat such diseases. It should be understood that the antibodies of the invention or antigen binding portion thereof can be used alone or in combination with an additional agent, e.g., a therapeutic agent, said additional agent being selected by the skilled artisan for its intended purpose. For example, the additional agent can be a therapeutic agent art-recognized as being useful to treat the disease or condition being treated by the antibody of the present invention. The additional agent also can be an agent which imparts a beneficial attribute to the therapeutic composition e.g., an agent which effects the viscosity of the composition. It should further be understood that the combinations which are to be included within this invention are those combinations useful for their intended purpose. The agents set forth below are illustrative for purposes and not intended to be limited. The combinations which are part of this invention can be the antibodies of the present invention and at least one additional agent selected from the lists below. The combination can also include more than one additional agent, e.g., two or three additional agents if the combination is such that the formed composition can perform its intended function. Preferred combinations are non-steroidal anti-inflammatory drug(s) also referred to as NSAIDS which include drugs like ibuprofen. Other preferred combinations are corticosteroids including prednisolone; the well known side-effects of steroid use can be reduced or even eliminated by tapering the steroid dose required when treating patients in combination with the anti-IL-12 antibodies of this invention. Non-limiting examples of therapeutic agents for rheumatoid arthritis with which an antibody, or antibody portion, of the invention can be combined include the following: cytokine suppressive anti-inflammatory drug(s) (CSAIDs); antibodies to or antagonists of other human cytokines or growth factors, for example, TNF, LT, IL-1, IL-2, IL-6, IL-7, IL-8, IL-15, IL-16, IL-18, EMAP-II, GM-CSF, FGF, and PDGF. Antibodies of the invention, or antigen binding portions thereof, can be combined with antibodies to cell surface molecules such as CD2, CD3, CD4, CD8, CD25, CD28, CD30, CD40, CD45, CD69, CD80 (B7.1), CD86 (B7.2), CD90, or their ligands including CD154 (gp39 or CD40L). Preferred combinations of therapeutic agents may interfere at different points in the autoimmune and subsequent inflammatory cascade; preferred examples include TNF antagonists like chimeric, humanized or human TNF antibodies, D2E7, (U.S. application Ser. No. 08/599,226 filed Feb. 9, 1996), cA2 (Remicade™), CDP 571, anti-TNF antibody fragments (e.g., CDP870), and soluble p55 or p75 TNF receptors, derivatives thereof, (p75TNFR1gG (Enbrel™) or p55TNFR1gG (Lenercept), soluble IL-13 receptor (sIL-13), and also TNFα converting enzyme (TACE) inhibitors; similarly IL-1 inhibitors (e.g., Interleukin-1-converting enzyme inhibitors, such as Vx740, or IL-1RA etc.) may be effective for the same reason. Other preferred combinations include Interleukin 11, anti-P7s and p-selectin glycoprotein ligand (PSGL). Yet another preferred combination are other key players of the autoimmune response which may act parallel to, dependent on or in concert with IL-12 function; especially preferred are IL-18 antagonists including IL-18 antibodies or soluble IL-18 receptors, or IL-18 binding proteins. It has been shown that IL-12 and IL-18 have overlapping but distinct functions and a combination of antagonists to both may be most effective. Yet another preferred combination are non-depleting anti-CD4 inhibitors. Yet other preferred combinations include antagonists of the co-stimulatory pathway CD80 (B7.1) or CD86 (B7.2) including antibodies, soluble receptors or antagonistic ligands. The antibodies of the invention, or antigen binding portions thereof, may also be combined with agents, such as methotrexate, 6-MP, azathioprine sulphasalazine, mesalazine, olsalazine chloroquinine/hydroxychloroquine, pencillamine, aurothiomalate (intramuscular and oral), azathioprine, cochicine, corticosteroids (oral, inhaled and local injection), beta-2 adrenoreceptor agonists (salbutamol, terbutaline, salmeteral), xanthines (theophylline, aminophylline), cromoglycate, nedocromil, ketotifen, ipratropium and oxitropium, cyclosporin, FK506, raparnycin, mycophenolate mofetil, leflunomide, NSAIDs, for example, ibuprofen, corticosteroids such as prednisolone, phosphodiesterase inhibitors, adensosine agonists, antithrombotic agents, complement inhibitors, adrenergic agents, agents which interfere with signalling by proinflammatory cytokines such as TNFα or IL-1 (e.g. IRAK, NIK, IKK, p38 or MAP kinase inhibitors), IL-1β converting enzyme inhibitors (e.g., Vx740), anti-P7s, p-selectin glycoprotein ligand (PSGL), TNFα converting enzyme (TACE) inhibitors, T-cell signalling inhibitors such as kinase inhibitors, metalloproteinase inhibitors, sulfasalazine, azathioprine, 6-mercaptopurines, angiotensin converting enzyme inhibitors, soluble cytokine receptors and derivatives thereof (e.g. soluble p55 or p75 TNF receptors and the derivatives p75TNFR1gG (Enbrel™)and p55TNFR1gG (Lenercept), sIL-1RI, sIL-1RII, sIL-6R, soluble IL-13 receptor (sIL-13)) and antiinflammatory cytokines (e.g. IL-4, IL-10, IL-11, IL-13 and TGFβ). Preferred combinations include methotrexate or leflunomide and in moderate or severe rheumatoid arthritis cases, cyclosporine. Non-limiting examples of therapeutic agents for inflammatory bowel disease with which an antibody, or antibody portion, of the invention can be combined include the following: budenoside; epidermal growth factor; corticosteroids; cyclosporin, sulfasalazine; aminosalicylates; 6-mercaptopurine; azathioprine; metronidazole; lipoxygenase inhibitors; mesalamine; olsalazine; balsalazide; antioxidants; thromboxane inhibitors; IL-1 receptor antagonists; anti-IL-1β, monoclonal antibodies; anti-IL-6 monoclonal antibodies; growth factors; elastase inhibitors; pyridinyl-imidazole compounds; antibodies to or antagonists of other human cytokines or growth factors, for example, TNF, LT, IL-1, IL-2, IL-6, IL-7, IL-8, IL-15, IL-16, IL-18, EMAP-II, GM-CSF, FGF, and PDGF. Antibodies of the invention, or antigen binding portions thereof, can be combined with antibodies to cell surface molecules such as CD2, CD3, CD4, CD8, CD25, CD28, CD30, CD40, CD45, CD69, CD90 or their ligands. The antibodies of the invention, or antigen binding portions thereof, may also be combined with agents, such as methotrexate, cyclosporin, FK506, rapamycin, mycophenolate mofetil, leflunomide, NSAIDs, for example, ibuprofen, corticosteroids such as prednisolone, phosphodiesterase inhibitors, adenosine agonists, antithrombotic agents, complement inhibitors, adrenergic agents, agents which interfere with signalling by proinflammatory cytokines such as TNFα or IL-1 (e.g. IRAK, NIK, IKK, p38 or MAP kinase inhibitors), IL-1β converting enzyme inhibitors (e.g., Vx740), anti-P7s, p-selectin glycoprotein ligand (PSGL), TNFα converting enzyme inhibitors, T-cell signalling inhibitors such as kinase inhibitors, metalloproteinase inhibitors, sulfasalazine, azathioprine, 6-mercaptopurines, angiotensin converting enzyme inhibitors, soluble cytokine receptors and derivatives thereof (e.g. soluble p55 or p75 TNF receptors, sIL-1RI, sIL-IR11, sIL-6R, soluble IL-13 receptor (sIL-13)) and antiinflammatory cytokines (e.g. IL-4, IL-10, IL-11, IL-13 and TGFβ). Preferred examples of therapeutic agents for Crohn's disease in which an antibody or an antigen binding portion can be combined include the following: TNF antagonists, for example, anti-TNF antibodies, D2E7 (U.S. application Ser. No. 08/599,226, filed Feb. 9, 1996), cA2 (Remicade™), CDP 571, anti-TNF antibody fragments (e.g., CDP870), TNFR-Ig constructs(p75TNFRIgG (Enbrel™) and p55TNFRIgG (Lenercept)), anti-P7s, p-selectin glycoprotein ligand (PSGL), soluble IL-13 receptor (sIL-13), and PDE4 inhibitors. Antibodies of the invention or antigen binding portions thereof, can be combined with corticosteroids, for example, budenoside and dexamethasone. Antibodies of the invention or antigen binding portions thereof, may also be combined with agents such as sulfasalazine, 5-aminosalicylic acid and olsalazine, and agents which interfere with synthesis or action of proinflammatory cytokines such as IL-1, for example, IL-1β converting enzyme inhibitors (e.g., Vx740) and IL-1ra. Antibodies of the invention or antigen binding portion thereof may also be used with T cell signaling inhibitors, for example, tyrosine kinase inhibitors 6-mercaptopurines. Antibodies of the invention or antigen binding portions thereof, can be combined with IL-1 I. Non-limiting examples of therapeutic agents for multiple sclerosis with which an antibody, or antibody portion, of the invention can be combined include the following: corticosteroids; prednisolone; methylprednisolone; azathioprine; cyclophosphamide; cyclosporine; methotrexate; 4-aminopyridine; tizanidine; interferon-β1a (Avonex; Biogen); interferon-β1b (Betaseron; Chiron/Berlex); Copolymer 1 (Cop-1; Copaxone; Teva Pharmaceutical Industries, Inc.); hyperbaric oxygen; intravenous immunoglobulin; clabribine; antibodies to or antagonists of other human cytokines or growth factors, for example, TNF, LT, IL-1, IL-2, IL-6, IL-7, IL-8, IL-15, IL-16, IL-18, EMAP-II, GM-CSF, FGF, and PDGF. Antibodies of the invention, or antigen binding portions thereof, can be combined with antibodies to cell surface molecules such as CD2, CD3, CD4, CD8, CD25, CD28, CD30, CD40, CD45, CD69, CD80, CD86, CD90 or their ligands. The antibodies of the invention, or antigen binding portions thereof, may also be combined with agents, such as methotrexate, cyclosporine, FK506, rapamycin, mycophenolate mofetil, leflunomide, NSAIDs, for example, ibuprofen, corticosteroids such as prednisolone, phosphodiesterase inhibitors, adensosine agonists, antithrombotic agents, complement inhibitors, adrenergic agents, agents which interfere with signalling by proinflammatory cytokines such as TNFα or IL-1 (e.g. IRAK, NIK, IKK, p38 or MAP kinase inhibitors), IL-1β converting enzyme inhibitors (e.g., Vx740), anti-P7s, p-selectin glycoprotein ligand (PSGL), TACE inhibitors, T-cell signalling inhibitors such as kinase inhibitors, metalloproteinase inhibitors, sulfasalazine, azathioprine, 6-mercaptopurines, angiotensin converting enzyme inhibitors, soluble cytokine receptors and derivatives thereof (e.g. soluble p55 or p75 TNF receptors, sIL-1 RI, sIL-1RII, sIL-6R, soluble IL-13 receptor (sIL-13)) and antiinflammatory cytokines (e.g. IL-4, IL-10, IL-13 and TGFβ). Preferred examples of therapeutic agents for multiple sclerosis in which the antibody or antigen binding portion thereof can be combined to include interferon-β, for example, IFNβ1a and IFNβ1b; copaxone, corticosteroids, IL-1 inhibitors, TNF inhibitors, and antibodies to CD40 ligand and CD80. The pharmaceutical compositions of the invention may include a “therapeutically effective amount” or a “prophylactically effective amount” of an antibody or antibody portion of the invention. A “therapeutically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic result. A therapeutically effective amount of the antibody or antibody portion may vary according to factors such as the disease state, age, sex, and weight of the individual; and the ability of the antibody or antibody portion to elicit a desired response in the individual. A therapeutically effective amount is also one in which any toxic or detrimental effects of the antibody or antibody portion are outweighed by the therapeutically beneficial effects. A “prophylactically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired prophylactic result. Typically, since a prophylactic dose is used in subjects prior to or at an earlier stage of disease, the prophylactically effective amount will be less than the therapeutically effective amount. Dosage regimens may be adjusted to provide the optimum desired response (e.g., a therapeutic or prophylactic response). For example, a single bolus may be administered, several divided doses may be administered over time or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. It is especially advantageous to formulate parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the mammalian subjects to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the active compound and the particular therapeutic or prophylactic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active compound for the treatment of sensitivity in individuals. An exemplary, non-limiting range for a therapeutically or prophylactically effective amount of an antibody or antibody portion of the invention is 0.01-20 mg/kg, more preferably 1-10 mg/kg, even more preferably 0.3-1 mg/kg. It is to be noted that dosage values may vary with the type and severity of the condition to be alleviated. It is to be further understood that for any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the compositions, and that dosage ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed composition. VII. Uses of the Antibodies of the Invention Given their ability to bind to hIL-12, the anti-hIL-12 antibodies, or portions thereof, of the invention can be used to detect hIL-12 (e.g. in a biological sample, such as serum or plasma), using a conventional immunoassay, such as an enzyme linked immunosorbent assays (ELISA), an radioimmunoassay (RIA) or tissue immunohistochemistry. The invention provides a method for detecting hIL-12 in a biological sample comprising contacting a biological sample with an antibody, or antibody portion, of the invention and detecting either the antibody (or antibody portion) bound to hIL-12 or unbound antibody (or antibody portion), to thereby detect hIL-12 in the biological sample. The antibody is directly or indirectly labeled with a detectable substance to facilitate detection of the bound or unbound antibody. Suitable detectable substances include various enzymes, prosthetic groups, fluorescent materials, luminescent materials and radioactive materials. Examples of suitable enzymes include horseradish peroxidase, alkaline phosphatase, β-galactosidase, or acetylcholinesterase; examples of suitable prosthetic group complexes include streptavidin/biotin and avidin/biotin; examples of suitable fluorescent materials include umbelliferone, fluorescein, fluorescein isothiocyanate, rhodamine, dichlorotriazinylamine fluorescein, dansyl chloride or phycoerythrin; an example of a luminescent material includes luminol; and examples of suitable radioactive material include 125I, 131I, 35S or 3H. Alternative to labeling the antibody, hIL-12 can be assayed in biological fluids by a competition immunoassay utilizing rhIL-12 standards labeled with a detectable substance and an unlabeled anti-hIL-12 antibody. In this assay, the biological sample, the labeled rhIL-12 standards and the anti-hIL-12 antibody are combined and the amount of labeled rhIL-12 standard bound to the unlabeled antibody is determined. The amount of hIL-12 in the biological sample is inversely proportional to the amount of labeled rhIL-12 standard bound to the anti-hIL-12 antibody. The Y61 and J695 antibodies of the invention can also be used to detect IL-12 from species other than humans, in particular IL-12 from primates. For example, Y61 can be used to detect IL-12 in the cynomolgus monkey and the rhesus monkey. J695 can be used to detect IL-12 in the cynomolgus monkey, rhesus monkey, and baboon. However, neither antibody cross reacts with mouse or rat IL-12 (see Example 3, subsection F). The antibodies and antibody portions of the invention are capable of neutralizing hIL-12 activity in vitro (see Example 3) and in vivo (see Example 4). Accordingly, the antibodies and antibody portions of the invention can be used to inhibit IL-12 activity, e.g., in a cell culture containing hIL-12, in human subjects or in other mammalian subjects having IL-12 with which an antibody of the invention cross-reacts (e.g. primates such as baboon, cynomolgus and rhesus). In a preferred embodiment, the invention provides an isolated human antibody, or antigen-binding portion thereof, that neutralizes the activity of human IL-12, and at least one additional primate IL-12 selected from the group consisting of baboon IL-12, marmoset IL-12, chimpanzee IL-12, cynomolgus IL-12 and rhesus IL-12, but which does not neutralize the activity of the mouse IL-12. Preferably, the IL-12 is human IL-12. For example, in a cell culture containing, or suspected of containing hIL-12, an antibody or antibody portion of the invention can be added to the culture medium to inhibit hIL-12 activity in the culture. In another embodiment, the invention provides a method for inhibiting IL-12 activity in a subject suffering from a disorder in which IL-12 activity is detrimental. IL-12 has been implicated in the pathophysiology of a wide variety of disorders (Windhagen et al., (1995) J. Exp. Med. 182: 1985-1996; Morita et al. (1998) Arthritis and Rheumatism. 41: 306-314; Bucht et al., (1996) Clin. Exp. Immunol. 103: 347-367; Fais et al. (1994) J Interferon Res. 14:235-238; Parronchi et al., (1997) Am. J. Path. 150:823-832; Monteleone et al., (1997) Gastroenterology. 112:1169-1178, and Berrebi et al, (1998) Am. J. Path 152:667-672; Parronchi et al (1997) Am. J. Path. 150:823-832). The invention provides methods for inhibiting IL-12 activity in a subject suffering from such a disorder, which method comprises administering to the subject an antibody or antibody portion of the invention such that IL-12 activity in the subject is inhibited. Preferably, the IL-12 is human IL-12 and the subject is a human subject. Alternatively, the subject can be a mammal expressing a IL-12 with which an antibody of the invention cross-reacts. Still further the subject can be a mammal into which has been introduced hIL-12 (e.g., by administration of hIL-12 or by expression of an hIL-12 transgene). An antibody of the invention can be administered to a human subject for therapeutic purposes (discussed further below). Moreover, an antibody of the invention can be administered to a non-human mammal expressing a IL-12 with which the antibody cross-reacts for veterinary purposes or as an animal model of human disease. Regarding the latter, such animal models may be useful for evaluating the therapeutic efficacy of antibodies of the invention (e.g., testing of dosages and time courses of administration). As used herein, the phrase “a disorder in which IL-12 activity is detrimental” is intended to include diseases and other disorders in which the presence of IL-12 in a subject suffering from the disorder has been shown to be or is suspected of being either responsible for the pathophysiology of the disorder or a factor that contributes to a worsening of the disorder. Accordingly, a disorder in which IL-12 activity is detrimental is a disorder in which inhibition of IL-12 activity is expected to alleviate the symptoms and/or progression of the disorder. Such disorders may be evidenced, for example, by an increase in the concentration of IL-12 in a biological fluid of a subject suffering from the disorder (e.g., an increase in the concentration of IL-12 in serum, plasma, synovial fluid, etc. of the subject), which can be detected, for example, using an anti-IL-12 antibody as described above. There are numerous examples of disorders in which IL-12 activity is detrimental. In one embodiment, the antibodies or antigen binding portions thereof, can be used in therapy to treat the diseases or disorders described herein. In another embodiment, the antibodies or antigen binding portions thereof, can be used for the manufacture of a medicine for treating the diseases or disorders described herein. The use of the antibodies and antibody portions of the invention in the treatment of a few non-limiting specific disorders is discussed further below: A. Rheumatoid Arthritis: Interleukin-12 has been implicated in playing a role in inflammatory diseases such as rheumatoid arthritis. Inducible IL-12p40 message has been detected in synovia from rheumatoid arthritis patients and IL-12 has been shown to be present in the synovial fluids from patients with rheumatoid arthritis (see e.g., Morita et al., (1998) Arthritis and Rheumatism 41: 306-314). IL-12 positive cells have been found to be present in the sublining layer of the rheumatoid arthritis synovium. The human antibodies, and antibody portions of the invention can be used to treat, for example, rheumatoid arthritis, juvenile rheumatoid arthritis, Lyme arthritis, rheumatoid spondylitis, osteoarthritis and gouty arthritis. Typically, the antibody, or antibody portion, is administered systemically, although for certain disorders, local administration of the antibody or antibody portion may be beneficial. An antibody, or antibody portion, of the invention also can be administered with one or more additional therapeutic agents useful in the treatment of autoimmune diseases. In the collagen induced arthritis (CIA) murine model for rheumatoid arthritis, treatment of mice with an anti-IL-12 mAb (rat anti-mouse IL-12 monoclonal antibody, C17.15) prior to arthritis profoundly supressed the onset, and reduced the incidence and severity of disease. Treatment with the anti-IL-12 mAb early after onset of arthritis reduced severity, but later treatment of the mice with the anti-IL-12 mAb after the onset of disease had minimal effect on disease severity. B. Crohn's Disease Interleukin-12 also plays a role in the inflammatory bowel disease, Crohn's disease. Increased expression of IFN-γ and IL-12 occurs in the intestinal mucosa of patients with Crohn's disease (see e.g., Fais et al., (1994) J Interferon Res. 14: 235-238; Parronchi et al., (1997) Amer. J Pathol. 150: 823-832; Monteleone et al., (1997) Gastroenterology 112: 1169-1178; Berrebi et al., (1998) Amer. J Pathol. 152: 667-672). Anti-IL-12 antibodies have been shown to suppress disease in mouse models of colitis, e.g., FNBS induced colitis IL-2 knockout mice, and recently in IL-10 knock-out mice. Accordingly, the antibodies, and antibody portions, of the invention, can be used in the treatment of inflammatory bowel diseases. C. Multiple Sclerosis Interleukin-12 has been implicated as a key mediator of multiple sclerosis. Expression of the inducible IL-12 p40 message or IL-12 itself can be demonstrated in lesions of patients with multiple sclerosis (Windhagen et al., (1995) J. Exp. Med. 182: 1985-1996, Drulovic et al., (1997) J Neurol. Sci. 147: 145-150). Chronic progressive patients with multiple sclerosis have elevated circulating levels of IL-12. Investigations with T-cells and antigen presenting cells (APCs) from patients with multiple sclerosis revealed a self-perpetuating series of immune interactions as the basis of progressive multiple sclerosis leading to a Th1-type immune response. Increased secretion of IFN-γ from the T cells led to increased IL-12 production by APCs, which perpetuated the cycle leading to a chronic state of a Th 1-type immune activation and disease (Balashov et al., (1997) Proc. Natl. Acad. Sci. 94: 599-603). The role of IL-12 in multiple sclerosis has been investigated using mouse and rat experimental allergic encephalomyelitis (EAE) models of multiple sclerosis. In a relapsing-remitting EAE model of multiple sclerosis in mice, pretreatment with anti-IL-12 mAb delayed paralysis and reduced clinical scores. Treatment with anti-IL-12 mAb at the peak of paralysis or during the subsequent remission period reduced clinical scores. Accordingly, the antibodies or antigen binding portions thereof of the invention may serve to alleviate symptoms associated with multiple sclerosis in humans. D. Insulin-Dependent Diabetes Mellitus Interleukin-12 has been implicated as an important mediator of insulin-dependent diabetes mellitus (IDDM). IDDM was induced in NOD mice by administration of IL-12, and anti-IL-12 antibodies were protective in an adoptive transfer model of IDDM. Early onset IDDM patients often experience a so-called “honeymoon period” during which some residual islet cell function is maintained. These residual islet cells produce insulin and regulate blood glucose levels better than administered insulin. Treatment of these early onset patients with an anti-IL-12 antibody may prevent further destruction of islet cells, thereby maintaining an endogenous source of insulin. E. Psoriasis Interleukin-12 has been implicated as a key mediator in psoriasis. Psoriasis involves acute and chronic skin lesions that are associated with a TH 1-type cytokine expression profile. (Hamid et al. (1996) J. Allergy Clin. Immunol. 1:225-231; Turka et al. (1995) Mol. Med. 1:690-699). IL-12 p35 and p40 mRNAs were detected in diseased human skin samples. Accordingly, the antibodies or antigen binding portions thereof of the invention may serve to alleviate chronic skin disorders such psoriasis. The present invention is further illustrated by the following examples which should not be construed as limiting in any way. The contents of all cited references, including literature references, issued patents, and published patent applications, as cited throughout this application are hereby expressly incorporated by reference. It should further be understood that the contents of all the tables attached hereto (see Appendix A) are incorporated by reference. TABLE 1 VH3 Family Germline Amino Acid Sequences Numbering according to Kabat (Joe9 VH included for comparison) SEQ germ- ID line NO: VH CDR H1 CDR H2 555 888 111111111122222222223 33333 33334444444444 5552225555555666666 666677777777778882228 123456789012345678901234567890 12345 67890123456789 012ABC3456789012345 67890123456789012ABC3 88888899999 45678901234 594 dp-29 EVQLVESGGGLVQPGGSLRLSCAASGFTFS DHYND WVRQAPGKGLEWVG RTRNKAHSYTTEYAASVKG RFTISRDDSKNSLYLQMNSLK TEDTAVYYCAR 595 DP-30 EVQLVESGGGLVQPGGSLRLSCAASGFTFS DHYNS WVRQAQGKGLELVG LIRNKANSYTTEYAASVKG RLTISREDSKNTLYLQMSSLK TEDLAVYYCAR 596 HC15-7 EVQLVESGGGLVQPGGSLRLSCAASGFTFS DHYMS WVRQAQGKGLELVG LIRNKANSYTTEYAASVKG RLTISREDSKNTMYLQMSNLK TEDLAVYYCAR 597 VHD26 EVQLLESGGGLVQPGGSLRLSCAASGFTFS DHYNS WVRQAQGKGLELVG LIRNKANSYTTEYAASVKG RLTISREDSKNTLYLQMSSLK TEDLAVYYCAR 598 DP-31 EVQLVESGGGLVQPGRSLRLSCAASGFTFD DYAMH WVRQAPGKGLEWVS GISW..NSGSIGYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTALYYCAK 599 DP-32 EVQLVESGGGVVRPGGSLRLSCAASGFTFD DYGHS WVRQAPGKGLEWVS GINW..NGGSTGYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTALYHCAR 600 DP-33 EVQLVESGGVVVQPGGSLRLSCAASGFTFD DYTMH WVRQAPGKGLEWVS LISW..DGGSTYYADSVKG RFTISRDNSKNSLYLQMNSLR TEDTALYYCAK 601 dp-35 QVQLVCSGGGLVKPGGSLRLSCAASGFTFS DYYMS WVRQAPGKGLEWVS YI..SSSGSTIYYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 602 VH3-8 QVQLLESGGGLVKPGGSLRLSCAASGFTFS DYYMS WVRQAPGKGLEWVS YI..SSSSSYTNYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 603 yac-9 EVQLVESGGGLVQPGGSLKLSCAASGFTFS GSAMH WVRQASGKGLEWVG RIRSKANSYATAYAASVKG RFTISRDDSKNTAYLQMNSLK TSDTAVYYCTR 604 dp-38 EVQLVESGGGLVKPGGSLRLSCAASGFTFS NAWMS WVRQAPGKGLEWVG RIKSKTDGGTTDYAAPVKG RFTISRDDSKNTLYLQMNSLK TEDTAVYYCTT 605 LSG2 EVQLVCSGGGLVKPGGSLRLSCAASGFTFS NAWMS WVRQAPGKGLEWVG RIESKTDGGTTDYAAPVKG RFTISRDDSKNTLYLQMNSLK TEDTAVYYCTT 606 LSG3 EVQLVESGGGLVKPGGSLRLSCAASGFTFS NAWMS WVRQAPGKGLEWVG RIKSKTDGGTTDTAAPVKG RFTISRDDSKNTLYLQMNSLK TEDTAVYYCTT 607 LSG4 EVQLVESGGGLVKPGGSLRLSCAASGFTFS NAWHS WVRQAPGKGLEWVG RIKSKTDGGTTNYAAPVKG RFTISRDDSKNTLYLQMNSLK TEDTAVYYCTT 608 LSG6 EVQLVESGGGLVKPGGSLRLSCAASGFTFS NAWMN WVRQAPGKGLEWVG RIKSKTDGGTTDYAAPVKG RFTISRDDSKNTLYLQMNSLK TEDTAVYYCTT 609 v3-15 EVQLVESGGALVKPGGSLRLSCAASGFTFS NAWMS WVRQAPGKGLEWVG RIKSKTDGGTTDYAAPVKG RFTISRDDSKNTLYLQMNSLK TEDTAVYYCTT 610 dp-39 EVQLVESGGGLVQPGGSLRLSCPASGFTFS NHYMS WVRQAPGKGLEWVS YI..SGDSGYTNYADSVKG RFTISRDNANNSPYLQMNSLR AEDTAVYYCVK 611 dp-40 EVQLVESGGGLVQPGGSLRLSCAASGFTFS NHYTS WVRQAPGKGLEWVS YS..SGNSGYTNYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCVK 612 dp-59 EVQLVESGGGLVQPGGSLRLSCAASGFTFS NSDMN WVHQAPGKGLEWVS GV..SWNGSRTHYADSVKG RFIISRDNSRNTLYLQTNSLR AEDTAVYYCVR 613 v3-16p EVQLVESGGGLVQPGGSLRLSCAASGFTFS NSDMN WARKAPGKGLEWVS GV..SWNGSRTHYVDSVKR RFIISRDNSRNSLYLQKNRRR AEDHAVYYCVR 614 v3-19p TVQLVESGGGLVEPGGSLRLSCAASGFTFS NSDMN WVRQAPGKGLEWVS GV..SWNGSRTHYADSVKG RFIISRDNSRNFLYQQMNSLR PEDMAVYYCVR 615 v3-13 EVHLVESGGGLVQPGGALRLSCAASGFTFS NYDMH WVRQATGKGLEWVS AN..GTAG.DTYYPGSVKG RFTISRENAKNSLYLQMNSLR AEDTAVYYCAR 616 DP-42 EVQLVETGGGLIQPGGSLRLSCAASGFTVS SNYMS WVRQAPGKGLEWVS VI.Y..SGGSTYYAQSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 617 dp-44 EVQLVQSGGGLVHPGGSLRLSCAGSGFTFS SYAMH NVRQAPGKGLEWVS AI...GTGGGTYYADSVKG RFTISRDNAKNSLYLQMNSLR AEDMAVYYCAR 618 DP-45 EVQLVQSGGGLVQPGGSLRLSCAGSGFTFS SYAMH WVRQAPGKGLEWVS AI...GTGGGTYYADSVKG RFTISRDNAKNSLYLQHNSLR AEDMAVYYCAR 619 dp-47 EVQLLESGGGLVQPGGSLRLSCAASGFTFS SYAMS WVRQAPGKGLEWVS AI..SGSGGSTYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAK 620 flm EVQLVESGGQLVQPGGSLRLSCSASGTTFS SYAHH WVRQAPGKGLEYVS AI..SSNGGSTYYADSVKG RFTISRDNSKNTLYVQMSSLR AEDTAVYYCVK 621 P1 EVQLVESGGGLVQPGGSLRLSCSASGFTFS SYAMH WVRQAPGKGLEYVS AI..SSNGGSTYYADSVKG RFTISRDNSKNTLYVQMSSLR AEDTAVYYCVK 622 v3-64 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYAMH WVRQAPGKGLEYVS AI..SSNGGSTYYANSVKG RFTISRDNSKNTLYLQNGSLR AEDNAVYYCAR 623 vh26 EVQLLESGGGLVQPGGSLRLSCAASGFTFS SYAMS WVRQAPGKGLEWVS AI..SGSGGSTYYGDSVKG RFTISRDNSKNTLYLQHNSLR AEDTAVYYCAK 624 B25 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYTDSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 625 b32e QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 626 B37 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMSSLR AEDTAVYYCAR 627 B43 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQNHSLR ACDTAVYYCAR 628 B48 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQNNSLR AEDTAVYYCAR 629 B52 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 630 B54 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 631 cos-8 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 632 dp-46 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 633 F2M QVQLVESGGGLVQPGGSLRLSCSASGFTFS SYAMH WVRQAPGKGLEYVS AI..SSNGGSTYYADSVKG RFTISRQNSKNTLYVQMSSLR AEDTAVYYCVK 634 F3 QVQLVESGGGLVQPGGSLRLSCSASGFTFS SYAMH WVRQAPGKGLEYVS AI..SSNGGSTYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 635 F7 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFAISRDNSKNTLYLQNNSLR AEDTAVYYCAR 636 hv3005 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMHSLR AEDTAVYYCAR 637 P2 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYAMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAK 638 dp-48 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYDMH WVRQATGKGLEWVS AI..GTAG.DTYYPGSVKG RFTISRENAKNSLYLQHNSLR AEDTAVYYCAR 639 dp-58 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYEMN WVRQAPGKGLLWVS YI..SSSGSTIYYAQSVKG RFTISRDNAKHSLYLQMNSLR AEDTAVYYCAR 640 B1 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR LRARLCITVRE 641 B13 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKHTLYLQMNSLR AEDTAVYYCAR 642 B18 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 643 B26 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH NVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 644 B28E QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLENVA VI..SYDGSHKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 645 B29E QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNRLYLQMNSLR AEDTAVYYCAR 646 B29M QVQLVESGGGVVQPGRSLRLScAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 647 B30 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..WYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 648 B32M QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 649 cos-3 QVQLVESGGGVVQPGGSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA Fl..RYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAK 650 dp-49 QVQLVESGGGVVQPGRSLRLScAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAK 651 dp-50 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..WYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 652 P6 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..WYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAK 653 P9E QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH NVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVRK˜˜˜ 654 v3-30 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..SYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLR AEDTAVYYCAR 655 v3-33 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA VI..WYDGSNKYYADSAKG RFTISRDHSTNTLFLQMNSLR AEDTAVYYCAR 656 dp-51 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYSMN WVRQAPGKGLENVS YI..SSSSSTIYYADSVKG RFTISRDNAKNSLYLQMNSLR DEDTAVYYCAR 657 dp-77 EVQLVESGGGLVKPGGSLRLSCAASGFTFS SYSMN WVRQAPGKGLEWVS SI..SSSSSYIYYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 658 HHG4 EVQLVESGGGLVKPGGSLRLSCAASGFTFS SYSMN WVRQAPGKGLEWVS SI...SSSSYIYYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 659 v3-21 EVQLVESGGGLVKPGGSLRLSCAASGFTFS SYSMN WVRQAPGKGLEWVS SI..SSSSSYIYYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 660 v3-48 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYSMN WVRQAPGKGLEWVS YI..SSSSSTIYYADSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 661 DP-52 EDQLVESGGGLVQPGGSLRPSCAASGFAFS SYVLH WVRRAPGKGPEWVS AIG...TGGDTYYADSVMG RFTISRDNAKKSLYLQMNSLI AEDMAVYYCAR 662 cos-6 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYWMH WVRQAPGKGLVNVS RI..NSDGSSTSYADSVKG RFTISRDNAKNTLYLQNNSLR AEDTAVYYCAR 663 dp-53 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYWMH WVRQAPGKGLVWVS RI..NSDGSSTSYADSVKG RFTISRDNAKNTLYLQNNSLR AEDTAVYYCAR 664 dp-54 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYWNS WVRQAPGKGLEWVA NI..KQDGSEKYYVDSVKG RFTISRDNAKNSLYLQHNSLR AEDTAVYYCAR 665 dp-87 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYWNH WVRQAPGKGLVWVS RI..NSDGSSTSYADSNKG QFTISRDNAKNTLYLQMNSLR AEDMAVYYCTR 666 VH3-11 EVQLVESGGGLVQPGGSLRLSCAASGFTFS SYWNS WVRQAPGKGLEWVA NI..KQDGSEKYYVDSVKG RFTISRDNAKNSLYLQMNSLR AEDTAVYYCAR 667 JOE9 QVQLVQSGGGVVQPGRSLRLSCAASGFTVS SYGMH WVRQAPGKGLEWVA FI..RYDGSNKYYADSVKG RFTISRDNSKNTLYLQMKSLR VH AEDTAVYYCTT Vλ1 Family Germline Amino Acid Sequences Numbering according to Kabat. (Joe9 VL included for comparison) SEQ ID NO: gene* VL CDR L1 CDR L2 222 1111111111222 22227772233333 333334444444444 5555555 55566666666667777777777888 1234567890123456789012 4567ABC8901234 567890123456789 0123456 78901234567890123456789012 CDR L3 99 888888 899999955 345678 9012345AB 668 1b DPL5 QSVLTQPPSVSAAPGQKVTISC SGSSSNIGNNY.VS WYQQLPGTAPKLLIY DNNKRPS GIPDRFSGSKSGTSATLGITGLQTGD EADYYC GTWDSSLSA 669 1d DPL4 QSVLTQPPSVSAAPGQKVTISC SGSSSDMGNYA.VS WYQQLPGTAPKLLIY ENNKRPS GIPDRFSGSKSGTSATLGITGLWPED EADYYC LAWDTSPRA 670 1c DPL2 QSVLTQPPSASGTPGQRVTISC SGSSSNIGSNT.VN WYQQLPGTAPKLLIY SNNQRPS GVPDRFSGSKSGTSASLAISGLQSED EADYYC AAWDDSLNG 671 1g DPL3 QSVLTQPPSASGTPGQRVTISC SGSSSNIGSNY.VY WYQQLPGTAPKLLIY RNNQRPS GVPDRFSGSKSGTSASLAISGLRSED EADYYC AAWDDSLSG 672 1a DPL1 QSVLTQPPSVSEAPRQRVTISC SGSSSNIGNN.AVN WYQQLPGKAPKLLIY YDDLLPS GVSDRFSGSKSGTSASLAISGLQSED EADYYC AAWDDSLNG 673 1f DPL9 QSVLTQPPSVSGAPGQRVTISC TGSSSNIGAGYVVH WYQQLPGTAPKLLIY GNSNRPS GVPDQFSGSKSGTSASLAITGLQSED EADYYC KAWDNSLNA 674 1e DPL8 QSVVTQIPSVSGAPGQRVTISC TGSSSNIGAGYDVH WYQQLPGTAPKLLIY GNSNRPS GVPDRFSGSKSGTSASLAITGLQAED EADYYC QSYDSSLSG 675 JOE9 SYVLTQPPSVSGTPGQRVTISC SGGRSNIGSNT.VK WYQQLPGTAPKLLIY GNDQRPS GVPDRFSGSKSGTSASLAITGVQAED VL EADYYC QSYDSSLRG *Williams, JMB, 1996, 264, 220-232 TABLE 2 H3 SEQ L3 SEQ RB assay PHA assay IFN gamma Clone ID NO: H3 ID NO: L3 koff IC50 (M) IC50 (M) IC50 (M) Joe9 wt 77 SGSYDY 110 QSYDSSLRGSRV 1.00E−01 1.50E−06 1.00E−06 Joe9 wt IgG1 77 SGSYDY 110 QSYDSSLRGSRV 5.00E−07 70-1 78 HGSHDN 110 Joe9 wt 1.34e−2 2.00E−07 70-1 IgG1 78 HGSHDN 110 Joe9 wt 2.00E−07 70-2 79 HGSYDY 110 Joe9 wt 3.30E−02 3-5.0E−7 70-7 80 RRRSNY 110 Joe9 wt 1.29E−01 3-5.0E−7 70-13 81 SGSIDY 110 Joe9 wt 7.20E−02 3-5.0E−7 78-34 77 wt 111 QSYDRGFTGSRV 1.64 e−2 2.00E−07 6.00E−07 78-25 77 wt 112 QSYDSSLRGSRV 5.00E−02 78-28 77 wt 112 QSYDSSLRGSRV 4.66E−02 78-35 77 wt 113 QSYDSSLTGSRV 4.99E−02 4.00E−07 79-1 77 wt 114 QSYDSSLWGSRV 2.00E−07 6.00E−07 101-14 79 70-2 111 78-34 7.52E−03 101-9 79 70-2 113 78-35 8.54E−03 101-19 81 70-13 111 78-34 4.56E−02 101-8 81 70-13 111 78-34 1.01E−02 101-4 81 70-13 113 78-35 9.76E−03 101-5 81 70-13 113 78-35 4.45E−02 101-11 (12) 78 70-1 111 78-34 4.5 e−3 3.00E−08 101-11 IgGi 78 70-1 111 78-34 1.60E−09 26-1 (2, 3) 78 70-1 114 79-1 7.4 e−3 6.00E−08 136-9 82 HGSHDD 115 QTYDISESGSRV 3.20E−03 136-10 82 HGSHDD 116 QSYDRGFTGSRV 1.40E−03 2.00E−09 136-14 83 HGSHDN 117 QTYDRGFTGSRV 1.10E−03 3.00E−10 1.00E−07 136-15 83 HGSHDN 118 QTYDKGFTGSSV 7.4 e−4 1.00E−10 2.00E−09 136-15 germline 83 HGSHDN 118 QTYDKGFTGSSV 4.60E−04 6.00E−09 136-16 83 HGSHDN 119 QSYDRRFTGSRV 6.10E−04 3.00E−10 5.00E−09 136-17 83 HGSHDN 120 QSYDWNFTGSRV 2.90E−05 2.00E−09 7.00E−09 136-18 83 HGSHDN 121 QSYDRGFTGSRV 1.10E−03 8.00E−10 136-21 83 HGSHDN 122 QSYDNGFTGSRV 4.20E−04 2.00E−09 136-24 83 HGSHDN 123 QSYDNAVTASKV 8.90E−04 1.00E−09 101-11 84 TT HGSHDN WGQG 124 QSYDRGFTGSRV 4.5 × 10−3 2 × 10−9 2.00E−08 136-15M1 85 AK ...... .... 124 QSYDRGFTGSRV 4.00E−10 149-4 86 .. ...... .S.. 124 ............ 1.37 × 10−3 8 × 10−11 3.00E−09 149-5 87 .. .....T .... 125 QSYDSSLWGTRV 1.02 × 10−3 1.2 × 10−10 3.00E−09 149-6 84 .. ...... .... 124 ............ 2.73 × 10−3 6 × 10−10 2.00E−09 149-7 84 .. ...... .... 126 .....D...... 1.13 × 10−3 9 × 10−10 3.00E−09 149-8 88 K. ...... .... 2.33 × 10−3 3 × 10−9 149-9 89 K. ...... ..H. 127 ...E......M. 3.54 × 10−3 1.8 × 10−10 149-11 90 .. ...... .S.. 128 ....N....A.. 1.43 × 10−2 2 × 10−10 4.00E−09 149-12 84 .. ...... .... 3.73 × 10−3 neutralising 149-13 84 .. ...... .... 2.22 × 10−3 5 × 10−10 149-14 91 .. .R..N. .... 1.5 × 10−10 6.00E−09 92 TT HGSHDN 124 QSYDRGFTGSRV 156-1 93 .. .....T 126 .....D...... 5.00E−03 156-2 93 .. .....T 129 .....R...... 156-3 93 .. .....T 128 ....N....A.. 9.00E−03 156-4 93 .. .....T 127 ...E.....SM. 156-5 93 .. .....T 130 .T..K.....S. 156-6 92 .. ...... 126 .....D...... 3.00E−03 156-7 92 .. ...... 129 .....R...... 156-8 92 .. ...... 128 ....N....A.. 156-9 92 .. ...... 127 ...E.....SM. 156-10 92 .. ...... 130 .T..K.....S. 156-11 94 .K ...... 126 .....D...... 156-12 94 .K ...... 129 .....R...... 156-13 94 .K ...... 128 ....N....A.. 156-14 94 .K ...... 127 ...E.....SM. 156-15 94 .K ...... 130 .T..K.....S. 156-16 93 .. .....T 124 ............ 156-17 92 .. .....T 125 ....SSLW.T.. 6.00E−03 156-18 93 .. .....T 125 ....SSLW.T.. 92 TT HGSHDN 124 QSYDRGFTGSRV 103-1 95 .. Q.R... 124 ............ 2.9 × 10−3 103-2 96 K. R.R... 130 .T..K.....S. 7.3 × 10−4 7.00E−11 1.00E−09 103-3 97 .. .....K 124 ............ 2.5 × 10−3 103-6 131 .....D...T.. 4.5 × 10−4 103-7 98 .. .....D 131 .....D...T.. 3.7 × 10−4 1.40E−10 1.00E−09 103-8 99 K. ...... 130 .T..K.....S. 3.3 × 10−4 6.00E−11 1.50E−09 103-14 & 9 100 KT HGSHDN 132 QSYDRGFTGSMV 6.7 e−4 4.00E−11 1.20E−09 103-8 & 2 100 KT HGSHDN 133 QTYDKGFTGSSV 5.3 e−4 1.50E−09 103-4 101 TT HGSHDN 134 QSYDRGFTGARV 1.6 e−4 8.60E−11 9.00E−10 103-152 101 TT HGSHDN 135 QSYERGFTGARV 8.60E−11 102 TT SGSYDY 136 QSYDRGFTGSRVF 170-1 102 .. ...... 137 .........FK.. 2.35E−03 170-2 102 .. ...... 138 .......VSAY.. 8.80E−04 170-3 102 .. ...... 139 ......L.VTK.. 1.11E−03 170-4 102 .. ...... 140 ......Y.A.... 8.11E−04 170-7 102 .. ...... 141 ..........K.. 5.30E−04 170-11 102 .. ...... 142 ......L..F... 4.40E−04 170-13 102 .. ...... 143 .........YK.. 1.59E−03 170-15 102 .. ...... 144 ......L..Y.L. 4.43E−03 170-19 103 .. H..H.N 145 ........DYK.. 1.00E−03 170-21 104 .. H..Q.N 146 .........P.L. 3.89E−03 170-22 102 .. ...... 147 ......L...... 5.60E−04 170-23 103 .. H..H.N 148 .........A..W 1.00E−03 2.00E−10 170-24 104 .. H..Q.N 149 .........Y... 2.80E−04 5.00E−10 170-35 105 A. H..Q.N 136 ............. 1.00E−05 170-38 150 .........P... 2.10E−04 170-39 151 ......M.S.... 2.79E−03 170-36 83 HGSHDN 152 QSYDRDSTGSRVF 4.00E−04 2.00E-10 170-25 106 HGSQDT 153 QSYDSSLRGSRVF 5.00E−04 5.00E−11 106 SGSYDY 136 QSYDRGFTGSRVF 73-B1 107 SGSYDY 154 H...SD....... 3.25E−03 >1E−8 73-B2 107 SGSYDY 155 H.SES........ 2.07E−03 73-B6 107 SGSYDY 156 H...NR....... 2.51E−03 >1E−8 73-C1 107 SGSYDY 157 H...SR....... 2.71E−03 >1E−8 73-C2 107 SGSYDY 158 ....SE....... 3.79E−03 73-C6 107 SGSYDY 159 ....T........ 3.96E−03 73-D1 107 SGSYDY 160 H...S........ 3.99E−03 73-D2 107 SGSYDY 161 ....T........ 3.56E−03 73-D4 107 SGSYDY 162 H...TK....... 5.36E−03 73-D5 107 SGSYDY 163 H.S.S........ 3.57E−03 73-E3 107 SGSYDY 164 ....SD....... 4.98E−03 73-E6 107 SGSYDY 165 H..ES........ 4.17E−03 73-F3 107 SGSYDY 166 ....APWS..... 7.08E−03 73-F5 107 SGSYDY 167 ...DSD....K.. 3.74E−03 73-G2 107 SGSYDY 168 HTN.S........ 3.98E−03 73-G3 107 SGSYDY 169 H...TR....... 3.50E−03 73-G4 107 SGSYDY 170 ....MR....... 6.58E−03 73-G5 107 SGSYDY 171 H.S.SDS...... 6.01E−03 73-G6 107 SGSYDY 172 ...NTD....... 6.30E−03 73-H2 107 SGSYDY 173 ....S........ 5.93E−03 73-F6 107 SGSYDY 174 H...M........ 5.87E−03 73-H3 107 SGSYDY 175 H...N........ 6.85E−03 73-C5 107 SGSYDY 176 H.H..D....... 4.84E−03 73-B7 108 HGSQDN 177 QSYDSSLRGSRV 2.50E−03 7.00E−09 136 QSYDRGFTGSRVF M2 A2 83 HGSHDN 178 ......IH..... 4.00E−02 M2 A4 83 HGSHDN 179 ....S..P..... 8.49E−03 M2 A5 83 HGSHDN 180 ....I.S...... 4.01E−02 M2 B1 83 HGSHDN 181 ....S.L...... 7.97E−03 M2 B3 83 HGSHDN 182 ....I.M...... 4.60E−02 M2 B4 83 HGSHDN 183 ....I.L...... 4.42E−02 M2 B5 83 HGSHDN 184 ....S.V...... 8.38E−03 M2 B6 83 HGSHDN 185 ......L.A.... 2.81E−02 M2 C2 83 HGSHDN 181 ....S.L...... 4.85E−02 M2 C3 83 HGSHDN 186 ....T.L...... 4.62E−02 M2 C4 83 HGSHDN 181 ....S.L...... 8.16E−03 M2 C5 83 HGSHDN 187 ....TAL...... 4.71E−02 M2 D1 83 HGSHDN 188 ....IR....... 3.71E−02 M2 D2 83 HGSHDN 189 ....IRS...... 3.85E−02 M2 D3 83 HGSHDN 190 ....NRL...... 3.33E−02 M2 D4 83 HGSHDN 191 ...ETS....... 5.81E−02 M2 D5 83 HGSHDN 192 ....SSS...... 5.18E−02 M2 D6 83 HGSHDN 193 ....S...A.... 5.01E−02 M2 E1 83 HGSHDN 194 .T..K.....S.. 5.32E−02 M2 E2 83 HGSHDN 195 ....N........ 4.77E−02 M2 E6 83 HGSHDN 196 ....T...K.... 9.77E−03 M2 F1 83 HGSHDN 197 ....SDV...... 6.16E−02 M2 H5 83 HGSHDN 198 ....A........ 9.90E−03 124 QSYDRGFTGSRV A5 83 HGSHDN 199 ......THPSML 1.12E−03 A12 83 HGSHDN 200 ......TTPRPM 1.43E−03 A4 83 HGSHDN 201 ......RNPALT 1.47E−03 A6 83 HGSHDN 202 ......THPWLH 1.87E−03 A10 83 HGSHDN 203 ......NSPATV 1.87E−03 A11 83 HGSHDN 204 ......TFPSPQ 2.07E−03 C2 83 HGSHDN 205 ......LNPSAT 2.23E−03 A8 83 HGSHDN 206 ......KSNKML 2.37E−03 B8 83 HGSHDN 207 ......HTAHLY 2.40E−03 C6 83 HGSHDN 208 ......QTPSIT 2.42E−03 A3 83 HGSHDN 209 ......YPRNIL 2.51E−03 B11 83 HGSHDN 210 ......ITPGLA 2.95E−03 B5 83 HGSHDN 211 ......QPHAVL 3.04E−03 C10 83 HGSHDN 212 ......NSPIPT 3.10E−03 C4 83 HGSHDN 213 ......TPNNSF 3.23E−03 C3 83 HGSHDN 214 ....S.VDPGPY 3.34E−03 B2 83 HGSHDN 215 ......RPRHAL 3.61E−03 A2 83 HGSHDN 216 ......PYHPIR 3.80E−03 C5 83 HGSHDN 217 ......PHTQPT 3.91E−03 A7 83 HGSHDN 218 ......HNNFSP 3.95E−03 C9 83 HGSHDN 219 ......PTHLPH 3.97E−03 B3 83 HGSHDN 220 ......TPSYPT 4.12E−03 C8 83 HGSHDN 221 ....S.TSNLLP 5.36E−03 B7 83 HGSHDN 222 ......DSNHDL 5.45E−03 A1 83 HGSHDN 223 ......LPRLTH 5.66E−03 C7 83 HGSHDN 224 ......IPTSYL 5.83E−03 C12 83 HGSHDN 225 ......LRVQAP 5.85E−03 B10 83 HGSHDN 226 ......LSDSPL 6.04E−03 B6 83 HGSHDN 227 ....S.SLRRIL 7.58E−03 A9 83 HGSHDN 228 ......PARTSP 7.98E−03 B9 83 HGSHDN 229 ......RAAHPQ 8.66E−03 124 QSYDRGFTGSRV 177-D7 83 HGSHDN 230 ......TQPABI 4.07E−04 177-G6 83 HGSHDN 231 ......THPTHI 5.50E−04 177-D9 83 HGSHDN 232 ......RIPABT 6.32E−04 177-C6 83 HGSHDN 233 ......THPVPA 7.94E−04 177-H5 83 HGSHDN 234 ......SBPIPA 1.32E−03 177-H9 83 HGSHDN 235 ......THPVPA 1.58E−03 177-H10 83 HGSHDN 236 ......THPTMY 3.44E−03 144-F1 83 HGSHDN 237 ......HHYTTF 5.80E−04 43-E3 83 HGSHDN 238 ......SHPAAE 8.00E−04 43-E9 83 HGSHDN 239 ......TIPSIE 8.00E−0 43-G2 83 HGSHDN 240 ......SSPAIM 7.00E−04 43-G3 83 HGSHDN 241 ......IWPNLN 9.00E−04 31-A6 83 HGSHDN 242 ......THPNLN 5.00E−04 31-B5 83 HGSHDN 243 ......THPSIS 5.00E−04 124 QSYDRGFTGSRV Y17 83 HGSHDN 244 QSYDRGSAPMIN 8.90E−05 4.50E−10 >1E−8 Y19 83 HGSHDN 245 QSYDRGHHPAMS 2.26E−04 3.00E−11 >1E−8 Y38 83 HGSHDN 246 ......THPSIT 5.08E−04 5.50E−11 2.60E−09 Y45 83 HGSHDN 247 ......TDPAIV 6.17E−04 4.00E−11 4.30E−09 Y61 83 HGSHDN 248 ......THPALL 2.75 e−4 4E−11 1.40E−10 Y61 IgG 83 HGSHDN 248 ......THPALL 1.50E−04 1.60E−11 1.30E−10 Y61 IgG germline 83 HGSHDN 248 ......THPALL 1.50E−04 1.60E−11 1.30E−10 1.60E−10 Y139 83 HGSHDN 249 ......SHPALT 5.92E−04 3E−11 4.50E−10 Y139 IgGi1 83 HGSHDN 249 ......SHPALT 1.00E−09 Y174 83 HGSHDN 250 ......TTPAPE 7.55E−04 6E−11 2.00E−09 Y177 83 HGSHDN 251 ......SHPTLI 6.61E−04 5E−11 1.00E−09 A5 83 HGSHDN 252 ......THPSML 4.50E−04 6.60E−11 A12 83 HGSHDN 253 ......TTPRPM 5.57E−04 2.50E−10 D9 83 HGSHDN 254 ......RLPAQT 8.21E−04 3.5E−09 G6 83 HGSHDN 255 ......THPLTI 5.08E−04 1E−10 1.00E−09 G6 IgG1 83 HGSHDN 255 ......THPLTI 1.00E−09 C6 83 HGSHDN 256 QSYDRGQTPSIT 1.07E−03 3.5E−10 1.00E−08 Y55 83 HGSHDN 257 QSYDRGTHFQMY 1.06E−03 1.40E−10 >1E−8 A4 83 HGSHDN 258 QSYDRGRNPALT 6.30E−04 2.50E−10 A03 83 HGSHDN 259 QSYDRGTHPLTM 3.04E−04 3.00E−11 4.00E−10 A03 IgG1 83 HGSHDN 260 QSYDRGTHPLTM 3.04 e−4 2.90E−11 3.80E−10 A03 IgG germline 83 HGSHDN 260 QSYDRGTHPLTM 2.50E−04 3.50E−11 1.75E−10 99-B11 83 HGSHDN 261 QSYDSGYTGSRV 5.40E−03 99-C11 83 HGSHDN 262 QSYDSGFTGSRV 5.70E−03 99-H4 83 HGSHDN 263 QSYDSRFTGSRV 4.80E−03 99-E9 83 HGSHDN 262 QSYDSGFTGSRV 5.40E−03 99-H7 83 HGSHDN 264 QSYPDGTPASRV 3.30E−03 99-H11 83 HGSHDN 265 QSYSTHMPISRV 4.90E−03 99-F6 83 HGSHDN 266 QSYDSGSTGSRV 4.90E−03 99-F7 83 HGSHDN 267 QSYPNSYPISRV 4.80E−03 99-F8 83 HGSHDN 268 QSYIRAPQQV 3.70E−03 99-F11 83 HGSHDN 262 QSYDSGFTGSRV 5.40E−03 99-G7 83 HGSHDN 269 QSYLKSRAFSRV 4.80E−03 99-G11 83 HGSHDN 270 QSYDSRFTGSRV 4.30E−03 124 QSYDRGFTGSRV L3.3R3M-B1 83 HGSHDN 271 ......FTGSMV 5.46E+00 L3.3R3M-B3 83 HGSHDN 272 ......FTGSMV 5.51E+00 L3.3R3M-C6 83 HGSHDN 273 ......FTGFDG 6.17E+00 L3.3R3M-F9 83 HGSHDN 274 ......TAPALS 4.99E+00 L3.3R3M-G8 83 HGSHDN 275 ......SYPALR 5.55E+00 L3.3R3M-H6 83 HGSHDN 276 ......NWPNSN 5.69E+00 L3.3R3M-H10 83 HGSHDN 277 ......TAPSLL 5.35E+00 L3.3R3M-A3 83 HGSHDN 278 ......FTGSMV 5.37E+00 L3.3R3M-F8 83 HGSHDN 279 ......TTPRIR 4.99E+00 L3.3R3M-G1 83 HGSHDN 280 ......FTGSMV 4.21E+00 L3.3R3M-G7 83 HGSHDN 281 ......FTGSMV 4.24E+00 L3.3R3M-H11 83 HGSHDN 282 ......MIPALT 3.95E+00 Y61-L94N 109 CKT HGSHDN 283 QSYDRNTHPALL 8.00E−11 Y61-L94F 109 CKT HGSHDN 284 QSYDRFTHPALL 6.00E−11 Y61-L94Y 109 CKT HGSHDN 285 QSYDRYTHPALL 2.00E−11 2.00E−11 Y61-L94Y IgG 109 CKT HGSHDN 285 QSYDRYTHPALL 1.27E−04 6.00E11 5.00−E11 4.00E11 Y61-L50Y 109 CKT HGSHDN 286 QSYDRGTHPALL 2.00E−11 2.00E−11 Y61-L50Y* IgG 109 CKT HGSHDN 286 QSYDRGTHPALL 6.98E−05 2.00E−11 3.00E−11 Y61-L50Y-H31E- 109 CKT HGSHDN 286 QSYDRGTHPALL 2.99E−05 6.00E−11 2.00E−11 IgG Y61-L50Y-H31E** 109 CKT HGSHDN 287 QSYDRYTHPALL 4.64E−05 1.00E−11 1.00E−11 L94Y** IgG J695 (Y61-L94Y- 109 CKT HGSHDN 287 QSYDRYTHPALL 5.14E−05 5.00E−11 1.00E−11 5.00E−12 L50Y IgG*) *CDR L2: L50G to Y **CDR L2: L50G to Y; CDR H1: H31S to E TABLE 3 CDR H1 CDR H2 Kabat Number 27 28 29 30 31 32 33 34 35 50 51 52 52A 53 54 55 Y61 VH F T F S S Y G M H F I R Y D G S Contact Positions X X X X X X X X X X Hypermutation Positions X X X X CDR H2 CDR H3 Kabat Number 56 57 58 59 60 61 62 63 64 65 95 96 97 98 101 102 Y61 VH N K Y Y A D S V K G H G S H D N Contact Positions X X X X X X X Hypermutation Positions X X CDR L1 CDR L2 Kabat number 24 25 26 27 27A 27B 28 29 30 31 32 33 34 50 51 52 Y61 VL S G G R S N I G S N T V K G N D Contact Positions X X X X X X Hypermutation Positions X X X CDR L2 CDR L3 Kabat number 53 54 55 56 89 90 91 92 93 94 95 95A 95B 95C 96 97 Y61 VL Q R P S Q S Y D R G T H P A L L Contact Positions X X X X X X X Hypermutation Positions X X X contact and/or hypermutation position X contact and/or hypermutation position mutated in Y61 TABLE 4 Neutralization Activity in the Presence of Excess Free IL-12 p40 PHA assay IC50 PHA assay IC50 (M) PHA assay IC50 (M) SEQ ID NO: Clone (M) p70:p40 1:0 p70:p40 1:20 p70:p40 1:50 VH: 47 136-15 2.00E−09 5.00E−09 4.00E−09 VL: 48 VH: 51 149-5 6.50E−09 7.00E−09 4.00E−09 VL: 52 VH: 53 149-6 9.00E−10 1.00E−09 1.00E−09 VL: 54 VH: 84 149-7 3.50E−09 2.50E−09 4.00E−09 VL: 126 VH: 23 Y61 IgG 1.80E−10 1.80E−10 VL: 24 VH: 65 AO3 IgG1 2.50E−10 2.20E−10 VL: 66 VH: 31 J695 1.00E−11 3.50E−11 VL: 32 EXAMPLES Example 1 Isolation of Anti-IL-12 Antibodies A. Screening for IL-12 Binding Antibodies Antibodies to hIL-12 were isolated by screening three separate scFv phage display libraries prepared using human VL and VH cDNAs from mRNA derived from human tonsils (referred to as scFv 1), tonsil and peripheral blood lymphocytes (PBL) (referred to as scFv 2), and bone marrow-derived lymphocytes (referred to as BMDL). Construction of the library and methods for selection are described in Vaughan et al. (1996) Nature Biotech. 14: 309-314. The libraries were screened using the antigens, human IL-12 p70 subunit, human IL-12 p40 subunit, chimaeric IL-12 (mouse p40/human p35), mouse IL-12, biotinylated human IL-12 and biotinylated chimaeric IL-12. IL-12 specific antibodies were selected by coating the antigen onto immunotubes using standard procedures (Marks et al., (1991) J. Mol. Biol. 222: 581-597). The scFv library 2 was screened using either IL-12, or biotinylated-IL-12, and generated a significant number of IL-12 specific binders. Five different clonotypes were selected, determined by BstN1 enzymatic digestion patterns, and confirmed by DNA sequencing. The main clonotypes were VHDP58/VLDPL11, VHDP77/VLDPK31, VHDP47/VL and VHDP77/VLDPK31, all of which recognized the p40 subunit of IL-12. Screening of the BMDL library with IL-12 p70 generated 3 different clonotypes. Two of these were found to be cross-reactive clones. The dominant clone was sequenced and consisted of VHDP35/VLDP. This clone recognizes the p40 subunit of IL-12. Screening of the scFv library 1, using IL-12 p70, did not produce specific IL-12 antibodies. In order to identify IL-12 antibodies which preferentially bind to the p70 heterodimer or the p35 subunit of IL-12, rather than the p40 subunit, the combined scFv 1+2 library, and the BMDL library were used. To select IL-12 antibodies that recognized the p70 heterodimer or p35 subunit, phage libraries were preincubated and selected in the presence of free p40. Sequencing of isolated clones revealed 9 different antibody lineages. Subunit preferences were further analyzed by ‘micro-Friguet’ titration. The supernatant containing scFv was titrated on biotin-captured IL-12 in an ELISA and the ED50 determined. The concentration of scFv producing 50% ED was preincubated with increasing concentrations of free p70 or p40 (inhibitors). A decrease in the ELISA signal on biotin-IL-12 coated plates was measured and plotted against the concentration of free p70 or p40. This provided the IC50 for each clone with respect to p70 and p40. If the titrations for both subunits overlaps, then the scFv binds to both p40 and p70. Any variation from this gives the degree of preference of p70 over p40. B. Affinity Maturation of Antibody Lineage Specific for IL-12 (Joe 9) The clones were tested for their ability to inhibit IL-12 binding to its receptor in an IL-12 receptor binding assay (referred to as RBA), and for their ability to inhibit IL-12 induced proliferation of PHA stimulated human blast cells (PHA assay), described in Example 3. Clone Joe 9 had the lowest IC50 value in both the RBA and the PHA assay, with an IC50 value of 1×10−6 M in both assays. In addition the heavy chain variable region (VH) of Joe 9 had the least number of changes compared to the closest germline sequence COS-3, identified from the VBASE database. Table 1 (see Appendix A) shows the VH3 family of germline sequences, of which COS-3 is a member, as well as members of Vλ1 family of germline sequences. Therefore, Joe 9 was selected for affinity maturation. The amino acids sequences of VH and VL of the Joe9 wild type (Joe9 wt) antibody are shown in FIG. 1A-1D. In order to increase the affinity of Joe 9, various mutations of the complementarity determining region 3 (CDR3) of both the heavy and light chains were made. The CDR3 variants were created by site-directed PCR mutagenesis using degenerate oligonucleotides specific for either the heavy chain CDR3 (referred to as “H3”) or the light chain CDR3 (referred to as “L3”), with an average of three base substitutions in each CDR3 (referred to as “spike”). PCR mutagenesis of the heavy chain CDR3 was performed using the degenerate heavy chain oligonucleotide containing a random mixture of all four nucleotides, 5′TGTCCCTTGGCCCCA(G)(T)(A)(G)(T)(C)(A)(T)(A)(G)(C)(T)(C)(C)(C)(A)(C)(T) GGTCGTACAGTAATA 3′ (SEQ ID NO: 580), and oligonucleotide pUC Reverse Tag GAC ACC TCG ATC AGC GGA TAA CAA TTTCAC ACA GG (SEQ ID NO: 581) to generate a repertoire of heavy chain CDR3 mutants. The parent light chain was amplified using Joe 9 reverse oligonucleotide (5′TGG GGC CAA GGG ACA3′ (SEQ ID NO:582) and the fdteteseq 24+21 oligonucleotide (5′-ATT CGT CCT ATA CCG TTC TAC TTT GTC GTC TTT CCA GAC GTT AGT-3′ (SEQ ID NO: 583). Complementarity between the two PCR products was used to drive annealing of the two fragments in a PCR assembly reaction and the full length recombined scFv library was amplified with pUC Reverse Tag (SEQ ID NO: 581) and fdTag 5′-ATT CGT CCT ATA CCG TTC-3′ (SEQ ID NO: 584). PCR mutagenesis of the light chain was performed using the light chain oligonucleotide containing a mixture of all four nucleotides 5′GGTCCCAGTTCCGAAGACCCTCGAACC(C)(C)(T)(C)(A)(G)(G)(C)(T) (G)(C)(T)(G)(T)(C)ATATGACTGGCAGTAATAGTCAGC 3′ (SEQ ID NO: 585), and Joe 9 reverse oligonucleotide 5′TGG GGC CAA GGG ACA3′ (SEQ ID NO: 586) to produce a repertoire of light chain CDR3 mutants. The parent heavy chain was amplified with pUC Reverse Tag (SEQ ID NO: 581) and HuJH3FOR oligonucleotide 5′TGAAGAGACGGTGACCATTGTCCC3′ (SEQ ID NO: 587). Complementarity between the two PCR products was used to drive annealing of the two fragments in a PCR assembly reaction and the full length recombined scFv library was amplified with Reverse Tag GAC ACC TCG ATC AGC G (SEQ ID NO: 588) and HuJλ 2-3 FOR NOT oligonucleotide 5′GAG TCA TTC TCG ACT TGC GGC CGC ACC TAG GAC GGT CAG CTT GGT CCC 3′ (SEQ ID NO: 589). Heavy chain CDR3 mutants were selected using 1 nM biotinylated IL-12, and washed for 1 h at room temperature in PBS containing free IL-12 or p40 at a concentration of 7 nM. Clones were analyzed by phage ELISA and those that bound to IL-12 were tested in BIAcore kinetic binding studies using a low density IL-12 chip (see procedure for BIAcore analysis in Example 5). Generally, BIAcore analysis measures real-time binding interactions between ligand (recombinant human IL-12 immobilized on a biosensor matrix) and analyte (antibodies in solution) by surface plasmon resonance (SPR) using the BIAcore system (Pharmacia Biosensor, Piscataway, N.J.). The system utilizes the optical properties of SPR to detect alterations in protein concentrations within a dextran biosensor matrix. Proteins are covalently bound to the dextran matrix at known concentrations. Antibodies are injected through the dextran matrix and specific binding between injected antibodies and immobilized ligand results in an increased matrix protein concentration and resultant change in the SPR signal. These changes in SPR signal are recorded as resonance units (RU) and are displayed with respect to time along the y-axis of a sensorgram. To determine the off rate (% ff), on rate (kon), association rate (Ka) and dissociation rate (Kd) constants, BIAcore kinetic evaluation software (version 2.1) was used. Clones that demonstrated an improvement in the koff rate were analyzed by neutralization assays which included inhibition by antibody of IL-12 binding to its receptor (RBA assay), inhibition of IL-12-induced proliferation in PHA stimulated human blast cells (PHA assay), and inhibition of IL-12-induced interferon gamma production by human blast cells (IFN gamma assay). A summary of the dissociation rates and/or IC50 values from neutralization assays of heavy chain CDR3 spiked clones 70-1 through 70-13 is presented in Table 2 (see Appendix A). Clone 70-1 displayed a koff rate that was better than the parent Joe 9 clone, and had the lowest IC50 value of 2.0×10−7 M. Therefore clone 70-1 was selected for conversion to complete IgG1. Light chain CDR3 mutants were selected using 1 nM biotin-IL-12 and washed with PBS containing 7 nM free p40. Clones were screened in phage ELISA and those that bound to IL-12 were tested in BIAcore binding analysis using low density IL-12 chips. Clones that displayed an off rate which was better than the parent Joe 9 clone were tested in neutralization assays which measured either, inhibition of IL-12 receptor binding, or inhibition of PHA blast cell proliferation. A summary of the dissociation rates and/or IC50 values from neutralization assays of light chain CDR3 mutant clones, 78-34 through 79-1, is presented in Table 2 (see Appendix A). Based on the koff rate, clones 78-34 and 78-35 displayed an improved koff rate compared to the parent Joe 9. Both of these clones were selected for combination analysis with heavy chain mutants. C. Combination Clones Mutant light and heavy chain clones that exhibited the best binding characteristics were used for combination and assembly of scFvs. Mutant clones with improved potency characteristics were combined by PCR overlap extension and pull-through of the mutated VH and VL segments as described above. Clones 101-14 through 26-1, shown in Table 2 (see Appendix A), were produced from the combination of heavy chain mutants (70-2, 70-13 and 70-1) with light chain mutants (78-34, 78-35 and 79-1). The koff rates and/or IC50 values from neutralization assays for these clones are presented in Table 2. BIAcore binding analysis identified clone 101-11, produced from the combination of the heavy chain CDR3 mutant clone 70-I with the light chain CDR3 mutant clone 78-34, as having an off rate of 0.0045 s−1. This koff rate was a significant improvement compared to the koff rates for either the heavy chain CDR3 mutant clone 70-1 (0.0134 s−1), or for the light chain CDR3 mutant clone 78-34 (0.0164 s−1) alone. Furthermore, clone 101-11 showed a significant improvement in neutralization assays. Accordingly, clone 101-11 was selected for affinity maturation as described below. D. Affinity Maturation of Clone 101-11 Further affinity maturation of clone 101-11 consisted of repeat cycles of PCR mutagenesis of both the heavy and light chain CDR3s of 101-11 using spiked oligonucleotide primers. The clones were selected with decreasing concentrations of biotinylated IL-12 (bio-IL-12). The binding characteristics of the mutated clones was assessed by BiAcore binding analysis and RBA, PHA neutralization assays. The koff rates and/or IC50 values for clones 136-9 through 170-25 are presented in Table 2 (see Appendix A). Clone 103-14 demonstrated an improved IC50 value in both the receptor binding assay and the PHA blast assay. Clone 103-14 also demonstrated a low kff rate, and accordingly was selected for further affinity maturation. E. Generation and Selection of Randomized Libraries of Clone 103-14 Light CDR3 The light chain CDR3 of clone 103-14 (QSYDRGFTGSMV (SEQ ID NO: 590)) was systematically randomized in 3 segments using 3 different libraries as outlined below, where X is encoded by a randomized codon of sequence NNS with N being any nucleotide and S being either deoxycytosine or deoxyguanidine. L3.1 = XXXXXXFTGSMV (SEQ ID NO:591) L3.2 = QSYXXXXXXSMV (SEQ ID NO:592) L3.3 = QSYDRGXXXXXX (SEQ ID NO:593) Randomized mutagenesis of all three light chain CDRs (referred to as L3.1, L3.2, and L3.3) of clone 103-14 was performed. The heavy chain CDR3 (referred to as H3) of clone 103-14 was not mutated. Four randomized libraries based on clone 103-14 (H3 and L3.1, L3.2 & L3.3) were constructed and subjected to a large variety of selection conditions that involved using limiting antigen concentration and the presence or absence of excess free antigen (p40 and p70). The outputs from selections (clones 73-BI through 99-GI1) were screened primarily by BIAcore, and on occasion with RBA and are shown in Table 2 (see Appendix A). Random mutagenesis of the light chain CDR of 103-14 generated clone Y61, which exhibited a significant improvement in IC50 value compared to the parent clone 103-14. Y61 was selected for conversion to a whole IgG1. Whole Y61-IgG1 has an IC50 value of approximately 130 pM determined by the PHA assay. The IC50 value was not affected by a 50 fold molar excess of free p40, demonstrating that free p40 did not cross-react with Y61 anti-IL-12 antibody to thereby decrease the antibody binding to the heterodimer. The full length sequences of Y61 heavy chain variable region and light chain variable region are shown below. Y61 Heavy Chain Variable Region Peptide Sequence (SEQ ID NO:23) CDRH1 QVQLVESGGGVVQPGRSLRLSCAASFTFS SYGMH WVRQAPGKGLEWVA CDRH2 FIRYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLRAEDTAVYYCKT CDRH3 HGSHDN WGQGTMVTVSS Y61 Light Chain Variable Region Peptide Sequence CDRL1 QSVLTQPPSVSGAPGQRVTISC SGGRSNIGSNTVK WYQQLPGTAPKLLIY (SEQ ID NO:24) CDRL2 GNDQRPS GVPDRFSGSKSGTSASLAITGLQAEDEADYYC CDRL3 QSYDRGTHPALL FGTGTKVTVLG CDR residues are assigned according to the Kabat definitions. Example 2 Mutation of Y61 at Hypermutation and Contact Positions Typically selection of recombinant antibodies with improved affinities can be carried out using phage display methods. This is accomplished by randomly mutating combinations of CDR residues to generate large libraries containing single-chain antibodies of different sequences. Typically, antibodies with improved affinities are selected based on their ability to reach an equilibrium in an antibody-antigen reaction. However, when Y61 scFV was expressed on phage surface and incubated with IL-12, selection conditions could not be found that would allow the system to reach normal antibody-antigen equilibrium. The scFV-phage remained bound to IL-12, presumably due to a non-specific interaction, since purified Y61 scFv exhibits normal dissociation kinetics. Since the usual methods of phage-display affinity maturation to Y61 (i.e. library generation and selections by mutagenesis of multiple CDR residues) could not be utilized, a new strategy was developed in which individual CDR positions were mutated. This strategy involves selection of appropriate CDR positions for mutation and is based on identification and selection of amino acids that are preferred selective mutagenesis positions, contact positions, and/or hypermutation positions. Contact positions are defined as residues that have a high probability of contact with an antigen when the antigen interacts with the antibody, while hypermutation positions are defined as residues considered to have a high probability for somatic hypermutation during in vivo affinity maturation of the antibody. Preferred selective mutagenesis positions are CDR positions that are both contact and hypermutation positions. The Y61 antibody was already optimized in the CDR3 regions using the procedure described in Example 1, therefore it was difficult to further improve the area which lies at the center of the antibody binding site using phage-display selection methods. Greater improvements in activity were obtained by mutation of potential contact positions outside the CDR3 regions by either removing a detrimental antigen-antibody contact or, engineering a new contact. Amino acids residues of Y61 which were considered contact points with antigen, and those CDR positions which are sites of somatic hypermutations during in vivo affinity maturation, are shown in Table 3 (see Appendix A). For Y61 affinity maturation, 15 residues outside CDR3, 3 residues within the L3 loop, and 5 residues in the H3 loop were selected for PCR mutagenesis. Y61 scFv gene was cloned into the pUCI 19(Sfi) plasmid vector for mutagenesis. Oligonucleotides were designed and synthesized with randomized codons to mutate each selected position. Following PCR mutagenesis, a small number of clones (˜24) were sequenced and expressed in a host cell, for example, in a bacterial, yeast or mammalian host cell. The expressed antibody was purified and the koff measured using the BIAcore system. Clones with improved off-rates, as compared to Y61, were then tested in neutralization assays. This procedure was repeated for other CDR positions. Individual mutations shown to have improved neutralization activity were combined to generate an antibody with even greater neutralization potency. The Y61 CDR positions that were mutated in order to improve neutralization potency, and the respective amino-acid substitutions at each position are shown in FIGS. 2A-2H. Off-rates, as determined by BIAcore analysis, are given. These off rates are also shown in the histograms to the right of each table. Results of these substitutions at positions H30, H32, H33, H50, H53, H54, H58, H95, H97, H101, L50, L92, L93, demonstrated that all amino-acid substitutions examined resulted in antibodies with poorer off-rates than Y61. At positions H52, L32, and L50, only a one amino acid substitution was found to improve the off-rate of Y61, all other changes adversely affected activity. For L50, this single Gly→Tyr change significantly (5-10 times) improved the neutralization potency of Y61. The results demonstrated the importance of these positions to Y61 activity, and suggest that in most cases phage-display was able to select for the optimal residues. However, at positions H31, H56, L30, and L94, several substitutions were found to improve Y61 off-rate, suggesting that these positions were also important for antigen binding, although the phage display approach did not allow selection of the optimal residues. Selective mutation of contact and hypermutation positions of Y61 identified amino acid residue L50 in the light chain CDR2, and residue L94 of the light chain CDR3, which improved the neutralization ability of Y61. A combination of these mutations produced an additive effect, generating an antibody, J695, that exhibited a significant increase in neutralization ability. The full length sequence of J695 heavy and light chain variable region sequences is shown below. J695 Heavy Chain Variable Region Peptide Sequence CDRH1 QVQLVESGGGVVQPGRSLRLSCAASGFTFS SYGMH WVRQAPGKGLEWVA (SEQ ID NO:31) CDRH2 FIRYDGSNKYYADSVKG RFTISRDNSKNTLYLQMNSLRAEDTAVYYCKT CDRH3 HGSHDN WGQGTMVTVSS J695 Light Chain Variable Region Peptide Sequence CDRL1 QSVLTQPPSVSGAPGQRVTISC SGSRSNIGSNTVK WYQQLPGTAPKLLIY (SEQ ID NO:32) CDRL2 YNDQRPS GVPDRFSGSKSGTSASLALTGLQAEDEADYYC CDRL3 QSYDRYTHPALL FGTGTKVTVLG CDR residues are assigned according to the Kabat definitions. A summary of the heavy and light chain variable region sequence alignments showing the lineage development of clones that were on the path from Joe9 to J695 is shown in FIGS. 1A-1D. The CDRs and residue numbering are according to Kabat. Example 3 Functional Activity of Anti-hIL-12 Antibodies To examine the functional activity of the human anti-human IL-12 antibodies of the invention, the antibodies were used in several assays that measure the ability of an antibody to inhibit IL-12 activity. A. Preparation of Human PHA-Activated Lymphoblasts Human peripheral blood mononuclear cells (PBMC) were isolated from a leukopac collected from a healthy donor by Ficoll-Hypaque gradient centrifugation for 45 minutes at 1500 rpm as described in Current Protocols in Immunology, Unit 7.1. PBMC at the interface of the aqueous blood solution and the lymphocyte separation medium were collected and washed three times with phosphate-buffered saline (PBS) by centrifugation for 15 minutes at 1500 rpm to remove Ficoll-Paque particles. The PBMC were then activated to form lymphoblasts as described in Current Protocols in Immunology, Unit 6.16. The washed PBMC were resuspended at 0.5-1×106 cells/ml in RPMI complete medium (RPMI 1640 medium, 10% fetal bovine serum (FBS), 100 U/ml penicillin, 100 μg/ml streptomycin), supplemented with 0.2% (v/v) PHA-P (Difco, Detroit, Mich.) and cultured for four days at 37° C. in a 5% CO2 atmosphere. After four days, cell cultures were split 1:1 by volume in RPMI complete medium, plus 0.2% (v/v) PHA-P and 50 U/ml recombinant human IL-2. Recombinant human IL-2 was produced by transfection of an expression vector carrying the human IL-2 cDNA into COS cells (see Kaufman et al., (1991) Nucleic Acids Res. 19, 4484-4490), and purified as described in PCT[US96/01382. Cell cultures were then incubated for an additional one to three days. PHA blast cells were harvested, washed twice with RPMI complete medium and frozen in 95% FBS, 5% DMSO at 10×106 cells/ml. PHA blast cells to be used for the IL-12 receptor binding assay (see section B) were collected after one day culture in the presence of IL-2, whereas PHA blast cells to be used for the PHA blast proliferation assay (see section C) and the interferon-gamma induction assay (see section D) were collected after three day culture in the presence of IL-2. B. IL-12 Receptor Binding Assay The ability of anti-IL-12 antibodies to inhibit binding of radiolabelled IL-12 to IL-12 receptors on PHA blasts were analyzed as follows. Various concentrations of anti-IL-12 antibody were preincubated for 1 hour at 37° C. with 50-100 pM 125I-hIL-12 (iodinated hIL-12 was prepared using the Bolton-Hunter labeling method to a specific activity of 20-40 mCi/mg from NEN-Dupont) in binding buffer (RPMI 1640, 5% FBS, 25 mM Hepes pH 7.4). PHA blast cells isolated as described above, were washed once and resuspended in binding buffer to a cell density of 2×107 cells/ml. PHA blasts (1×106 cells) were added to the antibody 125I-hIL-12 mixture and incubated for two hours at room temperature. Cell bound radioactivity was separated from free 125I-hIL-12 by centrifugation of the assay mixture for 30 seconds at room temperature, aspiration of the liquid and a wash with 0.1 ml binding buffer, followed by centrifugation at 4° C. for 4 min at 10,000×g. The cell pellet was examined for cell bound radioactivity using a gamma counter. Total binding was determined in the absence of antibody and non-specific binding was determined by inclusion of 25 nM unlabeled IL-12 in the assay. Incubations were carried out in duplicate. In the IL-12 receptor binding assay using the Y61 and J695 human anti-IL-12 antibodies, both antibodies demonstrated a comparable inhibition of IL-12 receptor binding. Y61 inhibited IL-12 receptor binding with an IC50 value of approximately 1.6×10−11M, while J695 had an IC50 value of approximately 1.1×10−11M. C. Human PHA Blast Proliferation Assay Anti-IL-12 antibodies were evaluated for their ability to inhibit PHA blast proliferation (which proliferation is stimulated by IL-12). Serial dilutions of anti-IL-12 antibody were preincubated for 1 hour at 37° C., 5% CO2 with 230 pg/ml hIL-12 in 100 ml RPMI complete medium in a microtiter plate (U-bottom, 96-well, Costar, Cambridge, Mass.). PHA blast cells isolated as described above, were washed once and resuspended in RPMI complete medium to a cell density of 3×105 cells/ml. PHA blasts (100 ml, 3×104 cells) were added to the antibody/hIL-12 mixture, incubated for 3 days at 37° C., 5% CO2 and labeled for 4-6 hours with 0.5 mCi/well (3H)-Thymidine (Amersham, Arlington Heights, Ill.). The culture contents were harvested onto glass fiber filters by means of a cell harvester (Tomtec, Orange, Conn.) and (3H)-Thymidine incorporation into cellular DNA was measured by liquid scintillation counting. All samples were assayed in duplicate. The results of neutralization in the presence of varying concentrations of p70:p40 (i.e. the ratio of IL-12 heterodimer to free p40 subunit) is shown in Table 4 (see Appendix A). Analysis of the Y61 human anti-IL-12 antibody in the PHA blast proliferation assay demonstrated that the antibody inhibited PHA blast proliferation with an IC50 value of approximately 1.8×10−10 M in the presence of IL-12 p70 alone, without any excess p40 (p70:p40 ratio of 1:0). In the presence of a 50-fold excess of free p40 (p70:p40 at a ratio of 1:50), the Y61 antibody inhibited PHA blast proliferation with an IC50 value of approximately 1.8×10−1M. This result demonstrates that the ability of Y61 to inhibit blast proliferation is not compromised by the presence of excess p40. The human anti-IL-12 antibody, J695 inhibited PHA blast proliferation with an IC50 value of approximately 1.0×10−11M in the presence of p70:p40 at a ratio of 1:0. In the presence of a p70:p40 ratio of 1:50, this antibody inhibited PHA blast proliferation with an IC50 value of approximately 5.8+2.8×10−12 M (n=2), demonstrating that the excess p40 had only a slight inhibitory effect on the antibody. Overall results demonstrate the improved neutralization activity of J695 in comparison with Y61 due to the mutations at L50 and L94. D. Interferon-Gamma Induction Assay The ability of anti-IL-12 antibodies to inhibit the production of IFNγ by PHA blasts (which production is stimulated by IL-12) was analyzed as follows. Various concentrations of anti-IL-12 antibody were preincubated for 1 hour at 37° C., 5% CO2 with 200-400 pg/ml hIL-12 in 100 ml RPMI complete medium in a microtiter plate (U-bottom, 96-well, Costar). PHA blast cells isolated as described above, were washed once and resuspended in RPMI complete medium to a cell density of 1×107 cells/ml. PHA blasts (100 μl of 1×106cells) were added to the antibody/hIL-12 mixture and incubated for 18 hours at 37° C. and 5% CO2. After incubation, 150 μl of cell free supernatant was withdrawn from each well and the level of human IFNγ produced was measured by ELISA (Endogen Interferon gamma ELISA, Endogen, Cambridge, Mass.). Each supernatant was assayed in duplicate. Analysis of human anti-hIL-12 antibody, Y61 in this assay demonstrated that Y61 inhibited human IFNγ production with an IC50 value of approximately 1.6×10−10M, while the human anti-IL-12 antibody, J695, inhibited human IFNγ production with an IC50 value of approximately 5.0+2.3×10−12 M (n=3). The result demonstrates the substantial improvement in the affinity of J695 as a result of the modifications at L50 and L94. E. Induction of Non-Human IL-12 From Isolated PBMC To examine the cross-reactivity of the human anti-hIL-12 antibodies with IL-12 from other species, non-human IL-12 was produced as follows. PBMC were separated from fresh heparinized blood by density gradient centrifugation as described above using lymphoprep (Nycomed, Oslo, Norway) for cynomolgus monkey, baboon, and dog, PBMC, Accu-paque (Accurate Chemical & Sci. Corp., Westbury, N.Y.) for dog PBMC or Lympholyte-rat (Accurate Chemical & Sci. Corp., Westbury, N.Y.) for rat PBMC. The PBMC were then induced to produce IL-12 as described (D'Andrea et al., (1992)J Exp. Med 176, 1387-1398, Villinger et al., (1995) J. Immunol. 155, 3946-3954, Buettner et al., (1998)Cytokine 10, 241-248). The washed PBMC were resuspended at 1×106 cells/ml in RPMI complete medium, supplemented with 0.0075% (wt/vol) of SAC (Pansorbin; Calbiochem-Behring Co., La Jolla, Calif.) or 1-5 mg/ml ConA (Sigma Chemical Co., St. Louis, Mo.) plus 0.0075% SAC and incubated for 18 hours at 37° C. in a 5% CO2 atmosphere. Cell-free and SAC-free medium was collected by centrifugation and filtering through 0.2 mm filters. IL-12 from the rhesus monkey was obtained as recombinant rhesus IL-12 from Emory University School of Medicine, Atlanta, Ga. F. Murine 2D6 Cell Proliferation Assay The murine T cell clone 2D6 proliferates in response to murine IL-2, IL-4, IL-7 and IL-12 (Maruo et al., (1997) J. Leukocyte Biol. 61, 346-352). A significant proliferation was also detected in response to rat PBMC supernatants containing rat IL-12. The cells do not respond to dog, cynomolgus, baboon or human IL-12. Murine 2D6 cells were propagated in RPMI complete medium supplemented with 50 mM beta-mercaptoethanol (βME) and 30 ng/ml murine IL-12. One day prior to the assay, the murine IL-12 was washed out and the cells were incubated overnight in RPMI complete medium plus βME. Serial dilutions of anti-IL-12 antibody were preincubated for 1 hour at 37° C., 5% CO2 with 40 pg/ml murine IL-12 in 100 ml RPMI complete medium plus βME in a microtiter plate (U-bottom, 96-well, Costar). 2D6 cells were washed once and resuspended in RPMI complete medium containing βME to a cell density of 1×105 cells/ml. 2D6 cells (100 μl, 1×104 cells) were added to the antibody/hIL-12 mixture, incubated for 3 days at 37° C., 5% CO2 and labeled for 4-6 hours with 0.5 mCi/well (3H)-Thymidine. The culture contents were harvested and counted by liquid scintillation counting. All samples were assayed in duplicate. G. Species Cross-Reactivity of J695 With Non-Human IL-12 Species cross-reactivity of J695 with non-human IL-12 was analyzed using PBMC's isolated from several non-human species. The presence of non-human IL-12 activity in the rat, dog, cynomolgus and baboon PBMC supernatants was confirmed using several bioassays described above, such as the murine 2D6 cell proliferation assay, the human PHA blast proliferation assay and the interferon-gamma induction assay by blocking the non-human PBMC induced responses with rabbit and/or sheep polyclonal antibodies to murine and/or human IL-12. Cross-reactivity of the human anti-hIL-12 antibodies Y61 and J695 with non-human IL-12 in PBMC supernatants or purified murine and rhesus IL-12 was then assessed in the same bioassay(s) by determining the J695 antibody concentration at which 50% inhibition of the response was observed. The species cross-reactivity results are summarized in Table 5. The results demonstrate that Y61 and J695 are each able to recognize IL-12 from monkeys (e.g, cynomolgus and rhesus IL-12 for Y61, and cynomolgus, rhesus and baboon for J695) and that J695 is approximately 35 fold less active on dog IL-12; neither Y61 nor J695 cross reacts with mouse or rat IL-12. H. Human cytokine specificity of J695 The specificity of J695 was tested in a competition ELISA in which a panel of human cytokines was tested for their ability to interfere with the binding of soluble J695 to immobilized human IL-12. The panel of human cytokines included IL-1α and IL-1β (Genzyme, Boston, Mass.), IL-2 (Endogen), IL-4, IL-10, IL-17, IFN-gamma, and TGF-β1 (R&D, Minneapolis, Minn.) IL-8 (Calbiochem), PDGF, IGF-I, and IGF-II (Boehringer Mannheim Corp., Indianapolis, Ind.), TNFα and lymphotoxin, IL-6, soluble IL-6 receptor, IL-11, IL-12 p70, IL-12 p40, M-CSF, and LIF. EBI-3, an IL-12 p40 related protein that is induced by Epstein-Barr virus infection in B lymphocytes (Devergne et TABLE 5 Species Cross Reactivity Data IC50 (M) Antibody Mouse IL-12 Rat IL-12 Dog IL-12 Cyno IL-12 Rhesus IL-12 Baboon IL-12 Human IL-12 Name Specificity Purified PBMC sup PBMC sup PBMC sup Purified PBMC sup Purified C17.15 rat-αmuIL12 3.0 × 10−11 R03B03 rabbit-αmuIL12 1.5 × 10−10 6.0 × 10−10 C8.6.2 mouse-αhuIL12 1.2 × 10−10 1.0 × 10−10 2.0 × 10−10 5.0 × 10−11 Y61 human-αhuIL12 Non- 2.2 × 10−10 1.0 × 10−10 1.7 × 10−10 neutralizing J695 human-αhuIL12 Non- Non- 3.5 × 10−10 1.0 × 10−11 1.0 × 10−11 1.5 × 10−11 5.0 × 10−12 neutralizing neutralizing al., (1996) J. Virol. 70, 1143-1153) was expressed as a human IgG-Fc chimera (EBI-3/Fc) Single-stranded salmon sperm DNA (Sigma) was also tested. Flat-bottom ELISA immunoassay microtiter plates (96 well, high binding, Costar) were coated overnight at 4° C. with 0.1 ml human IL-12 (2 μg/ml in 0.1M carbonate coating buffer (4 volumes 0.1M NaHCO3 plus 8.5 volumes 0.1M NaHCO3)). The plates were washed twice with PBS containing 0.05% Tween 20 (PBS-T), blocked with 200 μl of 1 mg/ml bovine serum albumin (BSA, Sigma) in PBS-T for 1 hour at room temperature, and again washed twice with PBS-T. Samples (100 μl) containing IL-12 antibody J695 (100 ng/ml) and each cytokine (2 nM) in PBS-T containing 50 μg/ml BSA (PBS-T/BSA) were added and incubated for 2 h at room temperature. The plates were washed 4 times and incubated for 1 h at room temperature with 100 μl mouse anti-human lambda-HRP (1:500 in PBS-T/BSA, Southern Biotech. Ass. Inc., Birmingham, Ala.). The plates were washed 4 times and developed with ABTS (Kirkegaard & Perry Lab., Gaithersburg, Md.) for 20-30 minutes in the dark. The OD450nm was read using a microplate reader (Molecular Devices, Menlo Park, Calif.). Percent binding was determined relative to J695 binding to the IL-12 coated p]ate in the absence of any soluble cytokine. The results demonstrated that J695 binding to immobilized human IL-12 was: blocked only by human IL-12 p70 and to a lesser extent, by human IL-12-p40 and not by any of the other cytokines tested. I. Binding to a Novel IL-12 Molecule An alternative IL-] 2 heterodimer has been described, in which the p35 subunit is replaced by a novel p19 molecule. P19 was identified using 3D homology searching for IL-6/IL-12 family members, and is synthesized by activated dendritic cells. P19 binds to p40 to form a p19/p40 dimer, which has IL-12-like activity, but is not as potent as the p35/p40 heterodimer in IFNγ induction. Antibodies which recognize p40 alone, but preferably in the context of a p70 molecule (e.g., J695 and Y61, see Example 3H) are expected to also neutralize both the p35/p40 molecules and the p19/p40 molecules. Example 4 In vivo Activity of Anti-hIL-12 Antibodies The in vivo effects of IL-12 antibodies on IL-12 induced responses were examined in a model modified from one used by Bree et al. to study the effect of human IL-12 on peripheral hematology in cynomolgus monkey Bree et al., (1994) Biochem Biophys Res. Comm. 204: 1150-1157. In those previous studies, administration of human IL-12 at 1 μg/kg/day for a period of 5 days resulted in a decrease in white blood cell count (WBC), especially in the lymphocyte and monocyte subsets after 24 hours. A decrease in the platelet count was observed at 72 hours. Levels of plasma neopterin, a marker of monocyte activation in response to IFN-γ, began to elevate at 24 hours and were the highest at 72 hours. In the first study with human anti-hiL-12 antibodies, fifteen healthy cynomolgus monkeys with an average weight of 5 kg, were sedated and divided into 5 groups (n=3). Group 1 received an intravenous (IV) administration of 10 mg/kg human intravenous immunoglobulin (IVIG, Miles, Eckhart, Ind., purified using protein A Sepharose). Group 2 received an intravenous administration of 1 mg/kg C8.6.2 (neutralizing mouse anti-human IL-12 monoclonal antibody). Group 3 received an intravenous administration of 10 mg/kg C8.6.2. Group 4 received an intravenous administration of 1 mg/kg Y61 (human anti-human IL-12 antibody, purified from CHO cell conditioned medium). Group 5 received an intravenous administration of 10 mg/kg Y61. One hour after the antibody administration all animals received a single subcutaneous (SC) injection of human IL-12 (1 μg/kg). Blood samples were taken at the following time points: baseline, 8, 24, 48, 96 and 216 hours, and analyzed for complete blood cell counts with differentials and serum chemistry. Serum human IL-12, C8.6.2 antibody, Y61 antibody, monkey IFN-gamma, monkey IL-10, monkey IL-6 and plasma neopterin levels were also measured. Animals treated with IL-12 plus IVIG control antibody (Group 1) showed many of the expected hematological changes, including decreases in WBC, platelets, lymphocyte count and monocyte count. These decreases were not seen or were less pronounced in the animals treated with either the C8.6.2 or Y61 antibody at 1 or 10 mg/kg (Groups 2-5). Serum or plasma samples were analyzed by ELISA specific for monkey IFN-gamma and monkey IL-10 (Biosource International, Camarillo, Calif.), monkey IL-6 (Endogen) and plasma neopterin (ICN Pharmaceuticals, Orangeburg, N.Y.). IFN-gamma, IL-10 or IL-6 were not detected in any of the IL-12 treated animals including the control animals treated with IL-12 plus IVIG. This was probably due to the low level exposure to IL-12 (only 1 dose of 1 μg/kg). Nevertheless, plasma neopterin levels increased about three fold in the IL-12 plus IVIG treated animals but did not change in all C8.6.2 or Y61 treated animals, including the lower dose (1 mg/kg) Y61 treated animals, indicating that Y61 was effective in vivo in blocking this sensitive response to IL-12. In a second study, in vivo activity and pharmacodynamics (PD) of J695 in cynomolgous monkeys were studied by administering exogenous rhIL-12 and determining if J695 could block or reduce the responses normally associated with rhIL-12 administration. Male cynomolgus monkeys (n=3 per group) were administered a single dose of 0.05, 0.2, or 1.0 mg/kg J695 or 1 mg/kg intravenous immunoglobulin (IVIG) as a bolus intravenous (IV) injection via a saphenous vein or subcutaneously (SC) in the dorsal skin. One hour following the administration of J695 or IVIG, all animals received a single SC dose of 1 μg/kg rhIL-12 in the dorsal skin. Blood samples were collected via the femoral vein up to 28 days after J695 administration. Serum was acquired from each blood sample and assayed for IL-12, J695, IFN-γ, and anti-J695 antibodies by ELISA. Neopterin was assayed by reverse-phase high performance liquid chromatography. The levels of neopterin, normalized with respect to the levels of neopterin that were measured before administration of J695 or rhIL-12, are shown in FIG. 3. To compare the suppression of neopterin between groups, the area under the curve (AUC) normalized for neopterin levels was calculated for each animal (Table 6). Neopterin exposure (AUC) was suppressed in a dose-dependent manner between approximately 71 and 93% in the IV groups and between 71 and 100% in SC groups, relative to the IVIG control groups. These results suggest that the dose of J695 necessary for 50% inhibition of the neopterin response (ED50) was less than 0.05 mg/kg when administered by either the IV or SC route. TABLE 6 Dose-Dependent Suppression of IL-12 Induced Neopterin by J695 in Cynomolgus Monkeys % Reduction of AUC of Neopterin AUC Route of dosing IVIG J695 Dose IVIG Dose Normalized Compared with or J695 and rhIL-12 (mg/kg) (mg/kg) Neopterin Levels Control Single IV injection — 1.0 1745 ± 845 0 followed 1 hr later by a 0.05 — 502 ± 135 71.3 dose of 1 μg/kg human 0.2 — 199 ± 316 88.6 IL-12 given SC 1.0 — 128 ± 292 92.7 Single SC injection — 1.0 1480 ± 604 0 followed 1 hour later 0.05 — 426 ± 108 71.2 by a dose of 1 μg/kg 0.2 — 395 ± 45.9 73.3 human IL-12 given SC 1.0 — 0 ± 109 100 Treatment with J695 also prevented or reduced the changes in hematology normally associated with rhIL-12 administration (leukopenia and thrombocytopenia). At 24 hours after rhIL-12 administration lymphocyte counts were reduced by approximately 50% when compared to baseline values in the control IV and SC IVIG treated groups. Administration of J695 either SC or IV at all three dose levels prevented this reduction, resulting in lymphocyte counts at 24 hours approximately the same as baseline values. At 48 hours after IL-12 administration, platelet counts in the groups treated with IV and SC IVIG were reduced by approximately 25% when compared to baseline values. An example dose schedule targeted to maintain serum levels above the 90% effect level would be 1 mg/kg IV and SC given approximately every other week, or 0.3 mg/kg given approximately every week, assuming slight accumulation during repeated dosing. This study demonstrates that antibody can be given safely to monkeys at such dosages. In independent toxicity studies, it was further found that up to 100 mg/kg of the antibody can be given safely to monkeys. J695 was also effective in preventing IFN-γ production in mice treated with a chimeric IL-12, a molecule which combines the murine p35 subunit with the human IL-12 p40 subunit. In contrast to human IL-12 which is biologically inactive in mice, this chimeric IL-12 retains biological function in mice, including induction of IFN-γ. In addition, the human p40 subunit allows the molecule to be bound and neutralized by J695. Chimeric IL-12 at a dose of 0.05 mg/kg i.p. was administered to female C3H/HeJ mice (10/experimental group) in five daily doses on days 0, 1, 2, 3, and 4. J695 was given on days 0, 2 and 4 at doses of 0.05, 0.01, 0.002, 0.0004, 0.00008, and 0.000016 mg/kg i.p., 30′ prior to the IL-12 injections. The control hulgGly was given IP. at a, dose of 0.05 mg/kg on days 0, 2, and 4. The mice were bled on day 5, and serum IFN-γ levels were determined by ELISA. The results demonstrated that J695 caused dose-dependent inhibition of IFN-γ production with an ED50 of approximately 0.001 mg/kg. Collectively, these results demonstrate that J695 is a potent inhibitor of 1′-] 2 activity in vivo. Example 5 Kinetic Analysis of Binding of Human Antibodies to Recombinant human IL-12 (rhIL-12) Real-time binding interactions between captured ligand (human anti-rhIL-12 antibody J695, captured on a biosensor matrix) and analyte (rhIL12 in solution) were measured by surface plasmon resonance (SPR) using the BIAcore system (Biacore AB, Uppsala, Sweden). The system utilizes the optical properties of SPR to detect alterations in protein concentration within a dextran biosensor matrix. Proteins are covalently bound to the dextran matrix at known concentrations. Antibodies are injected through the dextran matrix and specific binding between injected antibodies and immobilized ligand results in an increased matrix protein concentration and resultant change in the SPR signal. These changes in SPR signal are recorded as resonance units (RU) and are displayed with respect to time along the y-axis of a sensorgram. To facilitate immobilization of goat anti-human IgG (Southern Biotechnology Associates, Cat. No. 2040-01, Birmingham, Ala.) on the biosensor matrix, goat anti-human IgG is covalently linked via free amine groups to the dextran matrix by first activating carboxyl groups on the matrix with 100 mM N-hydroxysuccinimide (NHS) and 400 mM N-Ethyl-N′-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). Next, goat anti-human IgG is injected across the activated matrix. Thirty-five microliters of goat anti-human IgG (25 μg/ml), diluted in sodium acetate, pH 4.5, is injected across the activated biosensor and free amines on the protein are bound directly to the activated carboxyl groups. Unreacted matrix EDC-esters are deactivated by an injection of 1 M ethanolamine. Standard amine coupling kits were commercially available (Biacore AB, Cat. No. BR-1000-50, Uppsala, Sweden). J695 was diluted in HBS running buffer (Biacore AB, Cat. No. BR-1001-88, Uppsala, Sweden) to be captured on the matrix via goat anti-human IgG. To determine the capacity of rhIL12-specific antibodies to bind immobilized goat anti-human IgG, a binding assay was conducted as follows. Aliquots of J695 (25 μg/ml; 25 μl aliquots) were injected through the goat anti-human IgG polyclonal antibody coupled dextran matrix at a flow rate of 5 μl/min. Before injection of the protein and immediately afterward, HBS buffer alone flowed through each flow cell. The net difference in signal between the baseline and the point corresponding to approximately 30 seconds after completion of J695 injection was taken to represent the amount of IgG1 J695 bound (approximately 1200 RU's). Direct rhIL12 specific antibody binding to soluble rhILI12 was measured. Cytokines were diluted in HBS running buffer and 50 μl aliquots were injected through the immobilized protein matrices at a flow rate of 5 μl/min. The concentrations of rhIL-12 employed were 10, 20, 25, 40, 50, 80, 100, 150 and 200 nM. Prior to injection of rhIL-12, and immediately afterwards, HBS buffer alone flowed through each flow cell. The net difference in baseline signal and signal after completion of cytokine injection was taken to represent the binding value of the particular sample. Biosensor matrices were regenerated using 100 mM HCl before injection of the next sample. To determine the dissociation constant (off-rate), association constant (on-rate), BIAcore kinetic evaluation software (version 2.1) was used. Representative results of CHO derived J695 binding to rhIL-12 as compared to the COS derived J695, are shown in Table 7. TABLE 7 Binding of CHO or COS derived J695 to rhIL-12. rhIL12 bound, Source rhIL12, nM RU's Ab, bound, RU's rhIL12/AB CHO 200 1112 1613 1.48 CHO 150 1033 1525 1.45 CHO 100 994 1490 1.43 CHO 80 955 1457 1.40 CHO 50 912 1434 1.36 CHO 40 877 1413 1.33 CHO 25 818 1398 1.25 CHO 20 773 1382 1.20 CHO 10 627 1371 0.98 COS 200 1172 1690 1.49 COS 150 1084 1586 1.46 COS 100 1024 1524 1.44 COS 80 985 1489 1.42 COS 50 932 1457 1.37 COS 40 894 1431 1.34 COS 25 833 1409 1.27 COS 20 783 1394 1.20 COS 10 642 1377 1.00 Molecular kinetic interactions between captured J695 and soluble rhIL-12 were quantitatively analyzed using BIAcore technology. Several independent experiments were performed and the results were analyzed by the available BIAcore mathematical analysis software to derive kinetic rate constants, as shown in Table 8. TABLE 8 Apparent kinetic rate and affinity constants of J695 for rhIL-12. On-rate (M-1s-1), Off-rate (s-1), Kd (M), Antibody Source Avg. Avg. Avg. J695 CHO 3.52E+05 4.72E−05 1.34E−10 J695 COS 3.40E+05 2.61E−05 9.74E−11 There was a small difference between the calculated apparent constant (Kd) for the interaction between CHO derived J695 (Kd=1.34−10M−1) and COS derived J695 (Kd=9.74×10−11M−1) antibodies. The apparent dissociation constant (Kd) between J695 and rhIL 12 was estimated from the observed rate constants by the formula: Kd=off-rate/on-rate. To determine the apparent association and dissociation rate constant for the interaction between J695 and rhIL-12, several binding reactions were performed using a fixed amount of J695 (2 μg/ml) and varying concentrations of rhIL-12. Real-time binding interaction sensorgrams between captured J695 and soluble rhILl2 showed that both forms of antibody were very similar for both the association and dissociation phase. To further evaluate the capacity of captured IgG1 J695 mAb to bind soluble recombinant cytokine, a direct BIAcore method was used. In this method, goat anti-human IgG (25 μg/ml) coupled carboxymethyl dextran sensor surface was coated with IgG1 J695 (2 μg/ml) and recombinant cytokine was then added. When soluble rhIL12 was injected across a biosensor surface captured with CHO or COS derived IgG1 J695, the amount of signal increased as the concentration of cytokine in the solution increased. No binding was observed with rmIL12 (R&D Systems, Cat. No. 419-ML, Minneapolis, Minn.) or rh IL12 any concentration tested up to 1000 nM. These results support the conclusion that IgG1 J695 antibodies recognize a distinct determinant on rhIL-12. Table 9 shows the results of an experiment using BIAcore to demonstrate human IgG1 J695 mAb binding to only soluble rhIL12 and none of the other recombinant cytokines. TABLE 9 Epitope mapping of J695 using BIAcore technology. Captured ligand Captured ligand Soluble analyte COS J695 CHO J695 rec. human IL12 Positive Positive rec. murine IL12 Negative Negative Example 6 Further Studies of J695 Affinity for IL-12 Molecular kinetic interactions between J695 antibody and human IL-12 were quantitatively analyzed using BIAcore plasmon resonance technology, and apparent kinetic rate constants were derived. BIAcore technology was used to measure the binding of soluble rhIL-12 to solid phase captured J695. A goat anti-human IgG antibody was immobilized on the biosensor chips, then a fixed amount of J695 was injected and captured on the surface. Varying concentrations of rhIL-12 were applied, and the binding of IL-12 at different concentrations to J695 was measured as a function of time. Apparent dissociation and association rate constants were calculated, assuming zero-order dissociation and first order association kinetics, as well as a simple one-to-one molecular interaction between J695 and IL-12. Three independent experiments were performed, and the values shown are averages for the three experiments. From these measurements, the apparent dissociation (kd) and association (ka) rate constants were derived and used to calculate a Kd value for the interaction (see Table 10). The results indicated that J695 has a high affinity for rhIL-12. TABLE 10 Kinetic Parameters for the Interaction Between J695 and Human IL-12 Kinetic Parameter Value kd 3.71 ± 0.40 × 10−5 s−1 ka 3.81 ± 0.48 × 105 M−1s−1 Kd 9.74 × 10−11 M (14 ng/mL) Example 7 Characteristics and Neutralization Activity of C17.15, a Rat Monoclonal Antibody to Murine Interleukin-12 To assess the relevance of IL-12 treatment studies in mouse models of inflammation and autoimmunity using monoclonal antibodies specific for murine IL-12 to similar approaches in human disease, the interaction of C17.15, a rat anti-murine IL-12 monoclonal antibody with murine IL-12, was examined. The ability of C17.15 to neutralize murine IL-12 activity in a PHA blast proliferation assay, and to block murine IL-12 binding to cell surface receptors, was assessed, as were the kinetics of the C17.15-murine IL-12 binding interaction. In a human PHA blast proliferation assay (See Example 3), serial dilutions of C17.15 or rat IgG2a (a control antibody) were preincubated with 230 pg/mL murine. IL-12 for 1 hr at 37° C. PHA-stimulated blast cells were added to the antibody-IL-12 mixtures and incubated for 3 days at 37° C. The cells were subsequently labeled for 6 h with 1 μCi/well [3H]-thymidine. The cultures were harvested and [3H]-thvmidine incorporation was measured. Background non-specific proliferation was measured in the absence of added murine IL-12. All samples were assayed in duplicate. The IC50 (M) of C17.15 for recombinant murine IL-12 in this assay was found to be 1.4×10−11, as compared to the IC50 value of 5.8×10−12 observed for J695 for recombinant human IL-12 under the same conditions (see Table 11). TABLE 11 Comparison of the properties of anti-human IL-12 monoclonal antibody J695 and the rat anti-mouse IL-12 monoclonal antibody C17.15 Receptor Biomolecular Interaction Assay Binding PHA blast ka, on-rate kd, off-rate Assay Assay Antibody Epitope (M−1 s−1) (s−1) Kd (M) IC50 (M) IC50 (M) J695 Hu p40 3.81 × 105 3.71 × 10−5 9.74 × 10−11 1.1 × 10−11 5.8 × 10−12 C17.15 Mu p40 3.80 × 105 1.84 × 10−4 4.80 × 10−10 1.5 × 10−10 1.4 × 10−11 The ability of C17.15 to inhibit the binding of murine IL-12 to cellular receptors was also measured. Serial dilutions of C17.15 were pre-incubated for 1 hr at 37° C. with 100 pM [125I]-murine IL-12 in binding buffer. The 2D6 cells (2×106) were added to the antibody/[125I]-murine IL-12 mixture and incubated for 2 hours at room temperature. Cell-bound radioactivity was separated from free [125I]-IL-12, and the remaining cell-bound radioactivity was determined. Total binding of the labeled murine IL-12 to receptors on 2D6 cells was determined in the absence of antibody, and non-specific binding was determined by the inclusion of 25 nM unlabelled murine IL-12 in the assay. Specific binding was calculated as the total binding minus the non-specific binding. Incubations were carried out in duplicate. The results showed that C17.15 has an IC50 (M) of 1.5×10−10 for inhibition of binding of murine IL-12 to cellular receptors. The affinity of C17.15 for recombinant murine IL-12 was assessed by biomolecular interaction analysis. A goat anti-rat IgG antibody was immobilized on the biosensor chips, followed by an injection of a fixed amount of the C17.15 antibody, resulting in capture of C17.15 on the surface of the chip. Varying concentrations of recombinant murine IL-12 were applied to the C17.15 surface, and the binding of murine IL-12 to the immobilized C17.15 was measured as a function of time. Apparent dissociation and association rate constants were calculated, assuming a zero order dissociation and first order association kinetics as well as a simple one to one molecular interaction between the immobilized C17.15 and murine IL-12. From these measurements, the apparent-dissociation (Kd, off-rate) and association (ka, on-rate) rate constants were calculated. These results were used to calculate a Kd value for the interaction. An on-rate of 3.8×105M−1s−1, an off-rate of 1.84×104s−1, and a Kd of 4.8×10−10 was observed for the recombinant murine IL-12-C17.15 interaction. The observed activities of C17.15 in neutralizing murine IL-12 activity and binding to cell surface receptors, as well as the kinetics of binding of C17.15 to murine IL-12 correlate with similar measurements for the J695-rhIL-12 interaction. This indicates that the modes of action of the rat anti-mouse IL-12 antibody C17.15 and anti-human IL-12 antibody J695 are nearly identical based upon on-rate, off-rate, Kd, IC50, and the PHA blast assay. Therefore, C17.15 was used as a homologous antibody to J695 in murine models of inflammation and autoimmune disease to study the effects of IL-12 blockade on the initiation or progression of disease in these model animals (see Example 8). Example 8 Treatment of Autoimmune or Inflammation-Based Diseases in Mice by α-Murine IL-12 Antibody Administration A. Suppression of Collagen-Induced Arthritis in Mice by the α-IL-12 Antibody C17.15 A correlation between IL-12 levels and rheumatoid arthritis (RA) has been demonstrated. For example, elevated levels of IL-12 p70 have been detected in the synovia of RA patients compared with healthy controls (Morita et al (1998) Arthritis and Rheumatism. 41: 306-314). Therefore, the ability of C17.15, a rat anti-mouse IL-12 antibody, to suppress collagen-induced arthritis in mice was assessed. Male DBA/1 mice (10/group) were immunized with type II collagen on Day 0 and treated with C17.15, or control rat IgG, at 10 mg/kg intraperitoneally on alternate days from Day-1 (1 day prior to collagen immunization) to Day 12. The animals were monitored clinically for the development of arthritis in the paws until Day 90. The arthritis was graded as: O— normal; 1-arthritis localized to one joint; 2-more than one joint involved but not whole paw; 3-whole paw involved; 4-deformity of paw; 5-ankylosis of involved joints. The arthritis score of a mouse was the sum of the arthritic grades in each individual paw of the mouse (max=20). The results are expressed as mean±SEM in each group. The results, as shown in FIG. 4, indicate that an arthritic score was measurable in the C17.15-treated mice only after day 50 post-treatment, and that the peak mean arthritic score obtained with the C17.15-treated mice was at least 5-fold lower than that measured in the IgG-treated mice. This demonstrated that the rat anti-mouse IL-12 antibody C17.15 prevented the development of collagen-induced arthritis in mice. B. Suppression of Colitis in Mice by the Rat α-Murine IL-12 Antibody C17.15 IL-12 has also been demonstrated to play a role in the development/pathology of colitis. For example, anti-IL-12 antibodies have been shown to suppress disease in mouse models of colitis, e.g., TNBS induced colitis IL-2 knockout mice (Simpson et al. (1998) J. Exp. Med. 187(8): 1225-34). Similarly, anti-IL-2 antibodies have been demonstrated to suppress colitis formation in IL-10 knock-out mice. The ability of the rat anti-mouse IL-12 antibody, C17.15, to suppress TNBS colitis in mice was assessed in two studies (Davidson et al. (1998) J. Immunol. 161(6): 3143-9). In the first study, colitis was induced in pathogen free SJL mice by the administration of a 150 μL 50% ethanol solution containing 2.0 mg TNBS delivered via a pediatric umbilical artery catheter into the rectum. Control animals were treated with a 150 μL 50% ethanol solution only. A single dose of 0.75, 0.5, 0.25, or 0.1 mg C17.15 or 0.75 mg control rat IgG2a was given intravenously via the tail vein at day 11, and the therapeutic effect of the treatment was assessed by weighing the animals on days 11 and 17, and histological scoring at day 17. The weight of the mice treated with C17.15 increased within 48 hours of antibody treatment and normalized on day 6 after treatment. The effect of treatment with C17.15 was confirmed histologically. Further, assessments of IFN-γ secretion by CD4+ T-cells from spleen and colon of the treated mice, as well as IL-12 levels from spleen or colon-derived macrophages from the treated mice were also made (see Table 12). In the second study, the dosing was optimized and the mice were treated with a total dose of 0.1 mg or 0.5 mg C17.15 or 0.1 mg control IgG2a, respectively, split between days 12 and 14. It was found that the administration of C17.15 in a single dose at the dosage of 0.1 mg/mouse or 0.25 mg/mouse led to only partial improvement in TNBS-induced colitis and did not result in a significant reduction in the CD4+ T cell production of IFN-γ in vitro, but did result in a significant decrease in secretion of IL-12, compared to untreated controls. At a single dose of 0.5 mg/mouse or greater a response was observed. Taking the lowest dose of antibody tested and administering it in two divided injections (at days 12 and 14) improved the dosing regimen, indicating that multiple low doses can be more effective than a single bolus dose. The data obtained are shown in Table 12. TABLE 12 Anti-mouse Il-12 mAb C17.15 Suppresses Established Colitis in Mice IFN-γ IL-12 spleen spleen Weight (g) CD4+ macro- Disease Treatment Day cells phages Induction Day 0 Day 11 11 Day 17 (U/mL) (pg/ml) TNBS + Ethanol Control IgG2a 16.0 15.26 3326 300 0.75 mg TNBS + Ethanol C17.15 0.75 mg 16.0 20.21 1732 0 TNBS + Ethanol C17.15 0.5 mg 16.36 19.94 1723 0 TNBS + Ethanol C17.15 0.25 mg 16.28 17.7 3618 7 TNBS + Ethanol C17.15 0.1 mg 16.2 17.98 3489 22 Ethanol control — 20.76 21.16 1135 0 Administration of C17.15 monoclonal anti-IL-12 in two divided doses spaced one day apart totaling 0.1 mg/mouse or 0.05 mg/mouse led to complete reversal of colitis as assessed by wasting and macroscopic appearance of the colon. In addition, this dose schedule led to significant down-regulation of lamina propria T-cell production of IFN-γ and macrophage production of IL-12, so that the latter were comparable to levels seen in control ethanol-treated mice without TNBS-colitis. Thus, C17.15 administration to mouse models for TNBS colitis reversed the progression of the disease in a dose-dependent manner. C. Suppression of Experimental Autoimmune Encephalomyelitis (EAE) in Mice by α-IL-12 Antibodies It is commonly believed that IL-12 plays a role in the pathogenesis of multiple sclerosis (MS). The inducible IL-12 p40 message has been shown to be expressed in acute plaques of MS patients but not in inflammatory brain infarct lesions (Windhagen, A. et al. (1995) J. Exp. Med. 182: 1985-1996). T cells from MS patients (but not control T cells) stimulate IL-12 production from antigen-presenting cells through unregulated CD40L expression (Balashov, K. E. et al. (1997) Proc. Natl. Acad. Sci. USA 94: 599-603). MS patients have enhanced IFN-γ secretion that can be blocked with α-IL-12 antibodies in vitro (Balashov, K. E. et al. (1997) Proc. Natl. Acad. Sci. USA 94: 599-603). Elevated levels of serum IL-12 are detected in MS patients, but not in other neurological diseases (Nicoletti, F. et al. (1996) J Neuroimmunol. 70: 87-90). Increased IL-12 production has been shown to correlate with disease activity in MS patients (Cormabella, M. et al. (1998) J. Clin. Invest. 102: 671-678). The role of IL-12 in the pathogenesis of a murine model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), has been studied (Leonard, J. P. et al. (1995) J. Exp. Med. 181: 281-386; Banerjee, S. et al. (1998) Arthritis Rheum. (1998) 41: S33; and Segal, B. M. et al. (1998) J. Exp. Med. 187: 537-546). The disease in this model is known to be induced by T cells of the TH1 subset. Therefore, the ability of α-IL-12 antibodies to prevent the onset of acute EAE was assessed. An α-IL-12 antibody was found to be able to inhibit the onset of acute EAE, to suppress the disease after onset, and to decrease the severity of relapses in mice immunized with the autoantigen, rnyelin basic protein (Banerjee, S. et al. (1998) Arthritis Rheum. (1998) 41: S33). The beneficial effects of α-IL-12 antibody treatment in the mice persisted for over two months after stopping treatment. It has also been demonstrated that anti-IL-12 antibodies suppress the disease in mice that are recipients of encephalitogenic T cells by adoptive transfer (Leonard, J. P. et al. (1995) J. Exp. Med. 181: 281-386). Example 9 Clinical Pharmacology of J695 In a double blind, crossover study, 64 healthy, human male subjects were administered ascending doses of J695 or placebo. Measurement of complement fragment C3a prior to and 0.25 h after dosing did not demonstrate activation of the complement system. CRP and fibrinogen levels were only increased in subjects in whom symptoms of concurrent infections were observed. All subjects survived and the overall tolerability of J695 was very good. In no case did treatment have to be stopped because of adverse events (AEs). The most commonly observed AEs were headache and common cold/bronchitis, neither of which were categorized as severe. One of the study subjects, a 33-year-old single male, was suffering from psoriasis guttata at the start of the study. According to the randomized study design, this subject by chance received 5 mg/kg J695 by SC administration. Ten days prior to administration of the antibody, the subject showed only small discrete papular lesions on the arms and legs. At the time of the antibody administration, the subject displayed increased reddening, thickness of the erythematous plaques, and increased hyperkaratosis. One week after J695 administration, the subject reported an improvement in skin condition, including flattening of the lesions and a decrease in scaling. Shortly after the second administration of J695 (5 mg/kg IV), the subject's skin was totally cleared of psoriatic lesions, in the absence of any local treatment. Erythematous plaques covered with white scales reappeared concomitant with the expected clearance of J695 after the second administration of antibody. Example 10 Comparison of 1695 Produced by Two CHO Cell Lines For recombinant expression of J695, a recombinant expression vector encoding both the antibody heavy chain and the antibody light chain is introduced into dhfr-CHO cells (Urlaub, G. and Chasin, L.A. (1980) Proc. Natl. Acad. Sci. USA 77:4216-4220) by calcium phosphate-mediated transfection. Within the recombinant expression vector, the antibody heavy and light chain genes are each operatively linked to enhancer/promoter regulatory elements (e.g., derived from SV40, CMV, adenovirus and the like, such as a CMV enhancer/AdMLP promoter regulatory element or an SV40 enhancer/AdMLP promoter regulatory element) to drive high levels of transcription of the genes. The recombinant expression vector also carries a DHFR gene, which allows for selection of CHO cells that have been transfected with the vector using methotrexate selection/amplification. One hundred and fifty micrograms of an expression vector encoding the peptide sequences of the human antibody J695 were dissolved in 2.7 ml water in a 50 ml conical tube. Three hundred μL of 2.5 M CaCl2 were added and this DNA mixture was added dropwise to 3 ml of 2×HEPES buffered saline in a 50 ml conical tube. After vortexing for 5 sec and incubating at room temperature for 20 min, 1 mL was distributed evenly over each plate (still in F 12 medium), and the plates were incubated at 37° C. for 4 h. Liquid was removed by aspiration and 2 ml of 10% DMSO in F12 were added to each plate. The DMSO shock continued for 1 min, after which the DMSO was diluted by the addition of 5 ml PBS to each plate. Plates were washed twice in PBS, followed by the addition of 10 ml of alpha MEM, supplemented with H/T and 5% FBS (selective for cells expressing DHFR) and overnight incubation at 37° C. Cells were seeded into 96-well plates at a density of 100 cells per well, and plates were incubated at 37° C., 5% CO2 for two weeks, with one change of medium per week. Five days after the final medium change, culture supernatants were diluted 1:50 and tested using an ELISA specific for human IgG gamma chain. The clones yielding the highest ELISA signal were transferred from the 96-well plates to 12-well plates in 1.5 ml/well of Alpha MEM+5% dialyzed serum. After 3 days, another ELISA specific for human IgG gamma chain was performed, and the 12 clones with the greatest activity were split into the alpha MEM+5% dialyzed serum and 20 nM MTX. Cell line 031898 218 grew in the presence of 20 nM MTX without any apparent cell death or reduction in growth rate, produced 1.8 μg/ml hIgG in a three-day assay. T-25 cultures of 031898 is 218, growing in medium containing MTX, produced an average of 11.9 μg/ml of J695. The line, designated ALP903, was adapted to growth in suspension tinder serum-free conditions, where it produced 7.5 pg J695/cell/24 h. ALP903 cells, after initial selection in alpha MEM/5% FBS/20 nM MTX medium, were passed again in 20 nM MTX. The cells were cultured uider 100 nM MTX selection, followed by passaging in 500 nM MTX twice in the next 30 days. At that time the culture was producing 32 μg J695/mL/24 h. The culture was subcloned by limiting dilution. Subclone 218-22 produced 16.5 μg/mL in a 96-well plate in 2 days and 50.3 μg/mL of J695 in a 12-well dish in 2 days. Clone 218-22 was cultured in alpha MEM/5% dialyzed FBS/500 nM MTX for 38 days, followed by adaptation to serum-free spinner culture, as above. The average cell-specific productivity of the serum-free suspension culture, designated ALP 905, was 58 pg/cell/24 h. The first cell line used to produce J695 (ALP 903) resulted in lower yields of the antibody from culture than a second cell line, ALP 905. To assure that the ALP 905-produced J695 was functionally identical to that produced from ALP 903, both batches of antibodies were assessed for IL-12 affinity, for the ability to block IL-12 binding to cellular receptors, for the ability to inhibit IFN—Y induction by IL-12, and for the ability to inhibit IL-12-mediated PHA blast proliferation. The affinities of J695 batches ALP 903 and ALP 905 for IL-12 were determined by measuring the kinetic rate constants of binding to IL-12 by surface plasmon resonance studies (BIAcore analyses). The off-rate constant (kd) and the on-rate constant (ka) of antibody batches ALP903 and ALP905 for binding to rhIL-12 were determined in three experiments (as described in Example 3). The affinity, Kd, of binding to IL-12 was calculated by dividing the off-rate constant by the on-rate constant. Kd was calculated for each separate experiment and then averaged. The results showed that the determined kinetic parameters and affinity of binding to rhIL-12 were very similar for J695 batches ALP 903 and ALP 905: the calculated Kd was 1.19±0.22×10−10 M for batch ALP 903 and 1.49±0.47×10−10M for batch ALP 905 (see Table 13). The ability of J695 derived from both ALP 903 and ALP 905 to block binding of rhIL-12 to IL-12 receptors on human PHA-activated T-lymphoblasts was assessed (see Example 3). Each sample of J695 was tested at a starting concentration of 1×10−8 with 10-fold serial dilutions. The antibody was preincubated for 1 hour at 37° C. with 50 pM [125I]-human IL-12 in binding buffer. PHA blast cells were added to the antibody/[125I]-human IL-12 mixture and incubated for 2 h at room temperature. Cell bound radioactivity was separated from free [125I]-IL-12 by centrifugation and washing steps, and % inhibition was calculated. The IC50 values for J695 were determined from the inhibition curves using 4-parameter curve fitting and were confirmed by two independent experiments. Incubations were carried out in duplicate. The results for the two batches of J695 were very similar (see Table 13). The ability of J695 from both ALP 903 and ALP 905 cells to inhibit rhIL-12-induced IFN-γ production by human PHA-activated lymphoblasts in vitro was assessed. Serial dilutions of J695 were preincubated with 200 pg/mL rhIL-12 for 1 h at 37° C. PHA lymphoblast cells were added and incubated for 18 hours at 37° C. After incubation, cell free supernatant was withdrawn and the level of human IFN-γ determined by ELISA. The IC50 values from the inhibition curves were plotted against the antibody concentration using 4-parameter curve fitting. The results demonstrate that the ability of the two batches to inhibit IFN-γ production is very similar. The in vitro PHA blast cell proliferation assay was used to measure the neutralization capacity of ALP 903 and ALP 905 J695 for rhIL-12. Serial dilutions of J695 of each type were preincubated with 230 pg/mL human IL-12 for 1 h at 37° C. Next PHA blast cells were added and incubated for 3 days at 37° C. The cells were then labeled for 6 hours with 1 γCi/well [3H]-thymidine. The cultures were harvested and [3H]-thymidine incorporation measured. Non-specific proliferation (background) was measured in the absence of rhIL-12. The IC50 values for ALP 903 and ALP 905 J695 were found to be very similar and are set forth in Table 13. The activity of the J695 antibodies in neutralizing rhIL-12 activity, in blocking IL-12 binding to cell surface receptors, and in binding to rhIL-12 did not significantly differ from batch ALP 903 to batch ALP 905, and thus the antibodies produced from these two different cell types were equivalent. TABLE 13 Comparison of the Properties of J695 lots ALP 903 and ALP 905 PHA blast IFN-γ ka, On-rate kd, Off-rate RB assay Assay IC50 Assay IC50 Antibody (M−1, s−1) (s−1) Kd(M) IC50 (M) (M) (M) J695 3.75 × 105 4.46 × 10−5 1.19 × 10−10 3.4 × 10−11 5.5 × 10−12 5.8 × 10−12 ALP 903 J695 3.91 × 105 5.59 × 10−5 1.49 × 10−10 3.0 × 10−11 4.4 × 10−12 4.3 × 10−12 ALP 905 Equivalents Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Human interleukin 12 (IL-12) has recently been characterized as a cytokine with a unique structure and pleiotropic effects (Kobayashi, et al. (1989) J Exp Med. 170:827-845; Seder, et al. (1993) Proc. Natl. Acad. Sci. 90:10188-10192; Ling, et al. (1995) J Exp Med. 154:116-127; Podlaski, et al. (1992) Arch. Biochem. Biophys. 294:230-237). IL-12 plays a critical role in the pathology associated with several diseases involving immune and inflammatory responses. A review of IL-12, its biological activities, and its role in disease can be found in Gately et al. (1998) Ann. Rev. Immunol. 16: 495-521. Structurally, IL-12 is a heterodimeric protein comprising a 35 kDa subunit (p35) and a 40 kDa subunit (p40) which are both linked together by a disulfide bridge (referred to as the “p70 subunit”). The heterodimeric protein is produced primarily by antigen-presenting cells such as monocytes, macrophages and dendritic cells. These cell types also secrete an excess of the p40 subunit relative to p70 subunit. The p40 and p35 subunits are genetically unrelated and neither has been reported to possess biological activity, although the p40 homodimer may function as an IL-12 antagonist. Functionally, IL-12 plays a central role in regulating the balance between antigen specific T helper type (Th1) and type 2 (Th2) lymphocytes. The Th1 and Th2 cells govern the initiation and progression of autoimmune disorders, and IL-12 is critical in the regulation of Th 1 lymphocyte differentiation and maturation. Cytokines released by the Th1 cells are inflammatory and include interferon y (IFNγ), IL-2 and lymphotoxin (LT). Th2 cells secrete IL-4, IL-5, IL-6, IL-10 and IL-13 to facilitate humoral immunity, allergic reactions, and immunosuppression. Consistent with the preponderance of Th1 responses in autoimmune diseases and the proinflammatory activities of IFNγ, IL-12 may play a major role in the pathology associated with many autoimmune and inflammatory diseases such as rheumatoid arthritis (RA), multiple sclerosis (MS), and Crohn's disease. Human patients with MS have demonstrated an increase in IL-12 expression as documented by p40 mRNA levels in acute MS plaques. (Windhagen et al., (1995) J. Exp. Med. 182: 1985-1996). In addition, ex vivo stimulation of antigen-presenting cells with CD40L-expressing T cells from MS patients resulted in increased IL-12 production compared with control T cells, consistent with the observation that CD40/CD40L interactions are potent inducers of IL-12. Elevated levels of IL-12 p70 have been detected in the synovia of RA patients compared with healthy controls (Morita et al (1998) Arthritis and Rheumatism. 41: 306-314). Cytokine messenger ribonucleic acid (mRNA) expression profile in the RA synovia identified predominantly Th1 cytokines. (Bucht et al., (1996) Clin. Exp. Immunol. 103: 347-367). IL-12 also appears to play a critical role in the pathology associated with Crohn's disease (CD). Increased expression of INFγ and IL-12 has been observed in the intestinal mucosa of patients with this disease (Fais et al. (1994) J Interferon Res. 14:235-238; Parronchi et al., (1997) Am. J. Path. 150:823-832; Monteleone et al., (1997) Gastroenterology. 112:1169-1178, and Berrebi et al., (1998) Am. J. Path 152:667-672). The cytokine secretion profile of T cells from the lamina propria of CD patients is characteristic of a predominantly Th1 response, including greatly elevated IFNγ levels (Fuss, et al., (1996) J. Immunol. 157:1261-1270). Moreover, colon tissue sections from CD patients show an abundance of IL-12 expressing macrophages and IFNγ expressing T cells (Parronchi et al (1997) Am. J. Path. 150:823-832). Due to the role of human IL-12 in a variety of human disorders, therapeutic strategies have been designed to inhibit or counteract IL-12 activity. In particular, antibodies that bind to, and neutralize, IL-12 have been sought as a means to inhibit IL-12 activity. Some of the earliest antibodies were murine monoclonal antibodies (mAbs), secreted by hybridomas prepared from lymphocytes of mice immunized with IL-12 (see e.g., World Patent Application Publication No. WO 97/15327 by Strober et al.; Neurath et al. (1995) J. Exp. Med. 182:1281-1290; Duchmann et al. (1996) J. Immunol. 26:934-938). These murine IL-12 antibodies are limited for their use in vivo due to problems associated with administration of mouse antibodies to humans, such as short serum half life, an inability to trigger certain human effector functions and elicitation of an unwanted immune response against the mouse antibody in a human (the “human anti-mouse antibody” (HAMA) reaction). In general, attempts to overcome the problems associated with use of fully-murine antibodies in humans, have involved genetically engineering the antibodies to be more “human-like.” For example, chimeric antibodies, in which the variable regions of the antibody chains are murine-derived and the constant regions of the antibody chains are human-derived, have been prepared (Junghans, et al. (1990) Cancer Res. 50:1495-1502; Brown et al. (1991) Proc. Natl. Acad. Sci. 88:2663-2667; Kettleborough et al. (1991) Protein Engineering. 4:773-783). However, because these chimeric and humanized antibodies still retain some murine sequences, they still may elicit an unwanted immune reaction, the human anti-chimeric antibody (HACA) reaction, especially when administered for prolonged periods. A preferred IL-12 inhibitory agent to murine antibodies or derivatives thereof (e.g., chimeric or humanized antibodies) would be an entirely human anti-IL-12 antibody, since such an agent should not elicit the HAMA reaction, even if used for prolonged periods. However, such antibodies have not been described in the art and, therefore are still needed.
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<SOH> SUMMARY OF THE INVENTION <EOH>The present invention provides human antibodies that bind human IL-12. The invention also relates to the treatment or prevention of acute or chronic diseases or conditions whose pathology involves IL-12, using the human anti-IL-12 antibodies of the invention. In one aspect, the invention provides an isolated human antibody, or an antigen-binding portion thereof, that binds to human IL-12. In one embodiment, the invention provides a selectively mutated human IL-12 antibody, comprising: a human antibody or antigen-binding portion thereof, selectively mutated at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue such that it binds to human IL-12. In a preferred embodiment, the invention provides a selectively mutated human IL-12 antibody, comprising: a human antibody or antigen-binding portion thereof, selectively mutated at a preferred selective mutagenesis position with an activity enhancing amino acid residue such that it binds to human IL-12. In another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof is selectively mutated at more than one preferred selective mutagenesis position, contact or hypermutation positions with an activity enhancing amino acid residue. In another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof is selectively mutated at no more than three preferred selective mutagenesis positions, contact or hypermutation positions. In another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof is selectively mutated at no more than two preferred selective mutagenesis position, contact or hypermutation positions. In yet another preferred embodiment, the selectively mutated human IL-12 antibody or antigen-binding portion thereof, is selectively mutated such that a target specificity affinity level is attained, the target level being improved over that attainable when selecting for an antibody against the same antigen using phage display technology. In another preferred embodiment, the selectively mutated human IL-12 antibody further retains at least one desirable property or characteristic, e.g., preservation of non-cross reactivity with other proteins or human tissues, preservation of epitope recognition, production of an antibody with a close to a germline immunoglobulin sequence. In another embodiment, the invention provides an isolated human antibody, or antigen-binding portion thereof, that binds to human IL-12 and dissociates from human IL-12 with a k off rate constant of 0.1 s −1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC 50 of 1×10 −6 M or less. More preferably, the isolated human antibody or an antigen-binding portion thereof, dissociates from human IL-12 with a k off rate constant of 1×10 −2 s −1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −7 M or less. More preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a k off rate constant of 1×10 −3 s −1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −8 M or less. More preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a k off rate constant of 1×10 −4 s −1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less. More preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a k off rate constant of 1×10 −5 s −1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −10 M or less. Even more preferably, the isolated human antibody, or an antigen-binding portion thereof, dissociates from human IL-12 with a k off rate constant of 1×10 −5 s −1 or less, or inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −11 M or less. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −6 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3; and has a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and has a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. In a preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 7; and has a light chain variable region comprising the amino acid sequence of SEQ ID NO: 8. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 11; and has a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and has a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. In a preferred embodiment, the isolated human antibody has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 15; and has a light chain variable region comprising the amino acid sequence of SEQ ID NO: 16. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19; and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In a preferred embodiment, the isolated human antibody comprises a heavy chain constant region selected from the group consisting of IgG1, IgG2, IgG3, IgG4, IgM, IgA and IgE constant regions or any allelic variation thereof as discussed in Kabat et al. (Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition , U.S. Department of Health and Human Services, NIH Publication No. 91-3242), included herein by reference. In a more preferred embodiment, the antibody heavy chain constant region is IgG1. In another preferred embodiment, the isolated human antibody is a Fab fragment, or a F(ab′) 2 fragment or a single chain Fv fragment. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 404-SEQ ID NO: 469; and c) has a light chain CDR3 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 534-SEQ ID NO: 579. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO:335-SEQ ID NO: 403; and a light chain CDR2 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 506-SEQ ID NO: 533. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 288-SEQ ID NO: 334; and a light chain CDR1 comprising the amino acid sequence selected from the group consisting of SEQ ID NO: 470-SEQ ID NO: 505. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, comprising a the heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In a preferred embodiment, the isolated human antibody comprises a heavy chain constant region, or an Fab fragment or a F(ab′) 2 fragment or a single chain Fv fragment as described above. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) has a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25; and c) has a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27; and a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, has a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. In a preferred embodiment, the isolated human antibody, or an antigen-binding portion thereof, which has a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31, and a light chain variable region comprising the amino acid sequence of SEQ ID NO: 32. In a preferred embodiment, the isolated human antibody comprises a heavy chain constant region, or an Fab fragment, or a F(ab′) 2 fragment or a single chain Fv fragment as described above. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −6 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 1, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 3, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 5; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 2, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 4, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 6. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 1 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13, or a mutant thereof having one or more amino acid substitutions at a contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 9, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 1, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 13; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 10, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 12, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 14. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 21; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22, or a mutant thereof having one or more amino acid substitutions at preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 20, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 22. The invention also provides nucleic acid molecules encoding antibodies, or antigen binding portions thereof, of the invention. A preferred isolated nucleic acid encodes the heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 17. The isolated nucleic acid encoding an antibody heavy chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 19. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 21. In another embodiment, the isolated nucleic acid encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 23. In another embodiment, the isolated nucleic acid encodes the light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 18. The isolated nucleic acid encoding an antibody light chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 20. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 22. In another embodiment, the isolated nucleic acid encodes an antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 24. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which a) inhibits phytohemagglutinin blast proliferation in an in vitro PHA assay with an IC 50 of 1×10 −9 M or less; b) comprises a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27 and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25, a heavy chain CDR2 comprising the amino acid sequence of SEQ ID NO: 27, and a heavy chain CDR1 comprising the amino acid sequence of SEQ ID NO: 29; and c) comprises a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30, or a mutant thereof having one or more amino acid substitutions at a preferred selective mutagenesis position, contact position or a hypermutation position, wherein said mutant has a k off rate no more than 10-fold higher than the antibody comprising a light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26, a light chain CDR2 comprising the amino acid sequence of SEQ ID NO: 28, and a light chain CDR1 comprising the amino acid sequence of SEQ ID NO: 30. A preferred isolated nucleic acid encodes the heavy chain CDR3 comprising the amino acid sequence of SEQ ID NO: 25. The isolated nucleic acid encoding an antibody heavy chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 27. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 29. In another embodiment, the isolated nucleic acid encodes an antibody heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 31. In another embodiment, the isolated nucleic acid encodes the light chain CDR3 comprising the amino acid sequence of SEQ ID NO: 26. The isolated nucleic acid encoding an antibody light chain variable region. In another embodiment, the isolated nucleic acid encodes the CDR2 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 28. In another embodiment, the isolated nucleic acid encodes the CDR1 of the antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 30. In another embodiment, the isolated nucleic acid encodes an antibody light chain variable region comprising the amino acid sequence of SEQ ID NO: 32. In another aspect, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a k off rate constant of 0.1 s −1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC 50 of 1×10 −6 M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the V H 3 germline family, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from a member of the V λ 1 germline family, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact position or hypermutation position with an activity enhancing amino acid residue. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a k off rate constant of 0.1 s −1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC 50 of 1×10 −6 M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 595-667, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact position or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 669-675, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a k off rate constant of 0.1 s −1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC 50 of 1×10 −6 M or less. b) has a heavy chain variable region comprising the COS-3 germline amino acid sequence, wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. c) has a light chain variable region comprising the DPL8 germline amino acid sequence, wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In another embodiment, the invention provides an isolated human antibody, or an antigen-binding portion thereof, which has the following characteristics: a) that binds to human IL-12 and dissociates from human IL-12 with a k off rate constant of 0.1 s −1 or less, as determined by surface plasmon resonance, or which inhibits phytohemagglutinin blast proliferation in an in vitro phytohemagglutinin blast proliferation assay (PHA assay) with an IC 50 of 1×10 −6 M or less. b) has a heavy chain variable region comprising an amino acid sequence selected from a member of the V H 3 germline family, wherein the heavy chain variable region comprises a CDR2 that is structurally similar to CDR2s from other V H 3 germline family members, and a CDR1 that is structurally similar to CDR1 s from other V H 3 germline family members, and wherein the heavy chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue; c) has a light chain variable region comprising an amino acid sequence selected from a member of the V λ 1 germline family, wherein the light chain variable region comprises a CDR2 that is structurally similar to CDR2s from other V λ 1 germline family members, and a CDR1 that is structurally similar to CDR1s from other V λ 1 germline family members, and wherein the light chain variable region has a mutation at a preferred selective mutagenesis position, contact or hypermutation position with an activity enhancing amino acid residue. In a preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the heavy chain CDR3. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the light chain CDR3. In another embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the heavy chain CDR2. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the light chain CDR2. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the heavy chain CDR1. In another preferred embodiment, the isolated human antibody, or antigen binding portion thereof, has a mutation in the light chain CDR1. In another aspect, the invention provides recombinant expression vectors carrying the antibody-encoding nucleic acids of the invention, and host cells into which such vectors have been introduced, are also encompassed by the invention, as are methods of making the antibodies of the invention by culturing the host cells of the invention. In another aspect, the invention provides an isolated human antibody, or antigen-binding portion thereof, that neutralizes the activity of human IL-12, and at least one additional primate IL-12 selected from the group consisting of baboon IL-12, marmoset IL-12, chimpanzee IL-12, cynomolgus IL-12 and rhesus IL-12, but which does not neutralize the activity of the mouse IL-12. In another aspect, the invention provides a pharmaceutical composition comprising the antibody or an antigen binding portion thereof, of the invention and a pharmaceutically acceptable carrier. In another aspect, the invention provides a composition comprising the antibody or an antigen binding portion thereof, and an additional agent, for example, a therapeutic agent. In another aspect, the invention provides a method for inhibiting human IL-12 activity comprising contacting human IL-12 with the antibody of the invention, e.g., J695, such that human IL-12 activity is inhibited. In another aspect, the invention provides a method for inhibiting human IL-12 activity in a human subject suffering from a disorder in which IL-12 activity is detrimental, comprising administering to the human subject the antibody of the invention, e.g., J695, such that human IL-12 activity in the human subject is inhibited. The disorder can be, for example, Crohn's disease, multiple sclerosis or rheumatoid arthritis. In another aspect, the invention features a method for improving the activity of an antibody, or an antigen binding portion thereof, to attain a predetermined target activity, comprising: a) providing a parent antibody a antigen-binding portion thereof, b) selecting a preferred selective mutagenesis position selected from group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. c) individually mutating the selected preferred selective mutagenesis position to at least two other amino acid residues to hereby create a first panel of mutated antibodies, or antigen binding portions thereof; d) evaluating the activity of the first panel of mutated antibodies, or antigen binding portions thereof to determined if mutation of a single selective mutagenesis position produces an antibody or antigen binding portion thereof with the predetermined target activity or a partial target activity; e) combining in a stepwise fashion, in the parent antibody, or antigen binding portion thereof, individual mutations shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof. f) evaluating the activity of the combination antibodies, or antigen binding portions thereof to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity. g) if steps d) or f) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result an antibody with only a partial activity, additional amino acid residues selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 are mutated to at least two other amino acid residues to thereby create a second panel of mutated antibodies or antigen-binding portions thereof; h) evaluating the activity of the second panel of mutated antibodies or antigen binding portions thereof, to determined if mutation of a single amino acid residue selected from the group consisting of H35, H50, H53, H54, H95, H96, H97, H98, L30A and L96 results an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; i) combining in stepwise fashion in the parent antibody, or antigen-binding portion thereof, individual mutations of step g) shown to have an improved activity, to form combination antibodies, or antigen binding portions thereof; j) evaluating the activity of the combination antibodies or antigen binding portions thereof, to determined if the combination antibodies, or antigen binding portions thereof have the predetermined target activity or a partial target activity; k) if steps h) or j) do not result in an antibody or antigen binding portion thereof having the predetermined target activity, or result in an antibody with only a partial activity, additional amino acid residues selected from the group consisting of H33B, H52B and L31A are mutated to at least two other amino acid residues to thereby create a third panel of mutated antibodies or antigen binding portions thereof, l) evaluating the activity of the third panel of mutated antibodies or antigen binding portions thereof, to determine if a mutation of a single amino acid residue selected from the group consisting of H33B, H52B and L31A resulted in an antibody or antigen binding portion thereof, having the predetermined target activity or a partial activity; m) combining in a stepwise fashion in the parent antibody, or antigen binding portion thereof, individual mutation of step k) shown to have an improved activity, to form combination antibodies, or antigen binding portions, thereof; n) evaluating the activity of the combination antibodies or antigen-binding portions thereof, to determine if the combination antibodies, or antigen binding portions thereof have the predetermined target activity to thereby produce an antibody or antigen binding portion thereof with a predetermined target activity. In another aspect, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof, b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) repeating steps b) through d) for at least one other contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In one embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity is not further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; e) repeating steps b) through d) for at least one other contact or hypermutation position; f) combining, in the parent antibody, or antigen-binding portion thereof, individual mutations shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expressing said panel in an appropriate expression system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristics, wherein the property or characteristic is one that needs to be retained in the antibody; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment of the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position, contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least on retained property or characteristic, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected contact or hypermutation position; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristics, wherein the property or characteristic is one that needs to be retained; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting a preferred selective mutagenesis position, contact or hypermutation position within a complementarity determining region (CDR) for mutation, thereby identifying a selected preferred selective mutagenesis position contact or hypermutation position; c) individually mutating said selected preferred selective mutagenesis position, contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof for at least one other property or characteristic, wherein the property or characteristic is one that needs to be retained, until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. f) repeating steps a) through e) for at least one other preferred selective mutagenesis position, contact or hypermutation position; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and at least on retained other characteristic, to form combination antibodies, or antigen-binding portions thereof; and h) evaluating the activity of the combination antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In a preferred embodiment, the contact positions are selected from the group consisting of H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another preferred embodiment, the hypermutation positions are selected from the group consisting of H30, H31, H31B, H32, H52, H56, H58, L30, L31, L32, L53 and L93 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment the residues for selective mutagenesis are selected from the preferred selective mutagenesis positions from the group consisting of H30, H31, H31B, H32, H33, H52, H56, H58, L30, L31, L32, L50, L91, L92, L93, L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In a more preferred embodiment, the contact positions are selected from the group consisting of L50 and L94 and the other characteristic is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a recombinant parent antibody or antigen-binding portion thereof; that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and; c) individually mutating said selected contact or hypermutation position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof, and, expressing said panel in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other position within the CDR which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and other property or characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof; until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies or antigen-binding portions thereof, relative to the parent antibody or antigen-portion thereof, for changes in at least one other property or characteristic; f) repeating steps b) through e) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not affecting at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof, and h) evaluating the activity and the retention of at least one other characteristic or property of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment the invention provides a method to improve the affinity of an antibody or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other characteristic or property until an antibody, or antigen-binding portion thereof, with an improved activity, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation at a position other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies or antigen-binding portions thereof, relative to the parent antibody or antigen-portion thereof, for changes in at least one other property or characteristic; f) repeating steps b) through e) for at least one other CDR position which is neither the position selected under b) nor a position at H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; g) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity but not affecting at least one other property or characteristic, to form combination antibodies, or antigen-binding portions thereof with at least one retained property or characteristic; and h) evaluating the activity and the retention of at least one property of characteristic of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one retained property or characteristic, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, without affecting other characteristics, comprising: a) providing a parent antibody or antigen-binding portion thereof; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof; d) evaluating the activity of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof thereby identifying an activity enhancing amino acid residue; e) evaluating the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, for changes in at least one other property or characteristic until an antibody, or antigen-binding portion thereof, with an improved activity and retained other characteristic or property, relative to the parent antibody, or antigen-binding portion thereof, is obtained. In another embodiment, the invention provides a method for improving the activity of an antibody, or antigen-binding portion thereof, comprising: a) providing a parent antibody or antigen-binding portion thereof that was obtained by selection in a phage-display system but whose activity cannot be further improved by mutagenesis in said phage-display system; b) selecting an amino acid residue within a complementarity determining region (CDR) for mutation other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; c) individually mutating said selected position to at least two other amino acid residues to thereby create a panel of mutated antibodies, or antigen-binding portions thereof and expression in a non-phage display system; d) evaluating the activity and retention of at least one other characteristic or property of the panel of mutated antibodies, or antigen-binding portions thereof, relative to the parent antibody or antigen-binding portion thereof, thereby identifying an activity enhancing amino acid residue; e) repeating steps b) through d) for at least one other CDR position which is neither the position selected under b nor other than H30, H31, H31B, H32, H33, H35, H50, H52, H52A, H53, H54, H56, H58, H95, H96, H97, H98, H101, L30, L31, L32, L34, L50, L52, L53, L55, L91, L92, L93, L94 and L96; f) combining, in the parent antibody, or antigen-binding portion thereof, at least two individual activity enhancing amino acid residues shown to have improved activity and not to affect at least one other characteristic or property, to form combination antibodies, or antigen-binding portions thereof; and g) evaluating the activity and retention of at least one other characteristic or property of the combination antibodies, or antigen-binding portions thereof with two activity enhancing amino acid residues, relative to the parent antibody or antigen-binding portion thereof until an antibody, or antigen-binding portion thereof, with an improved activity and at least one other retained characteristic or property, relative to the parent antibody, or antigen-binding portion thereof, is obtained. Preferably, the other characteristic or property is selected from 1) preservation of non-crossreactivity with other proteins or human tissues, 2) preservation of epitope recognition, i.e. recognizing p40 epitope preferably in the context of the p70 p40/p35 heterodimer preventing binding interference from free, soluble p40 and/or 3) to produce an antibody with a close to germline immunoglobulin sequence
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20040701
|
20090317
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20050106
|
59649.0
| 4
|
HISSONG, BRUCE D
|
HUMAN ANTIBODIES THAT BIND HUMAN IL-12
|
UNDISCOUNTED
| 1
|
CONT-ACCEPTED
| 2,004
|
|||
10,884,855
|
ACCEPTED
|
Managing activation of cardholders in a secure authentication program
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Merchants or other third parties can add an activation link on their Internet site. The activation link can be associated with text or an image, for example a logo. The activation link can be presented to cardholders visiting an Internet site prior to the cardholder initiating a transaction. Upon selecting the activation link, a cardholder is redirected to activation site. The activation site can be a generic site intended for any cardholder, or an activation site specifically tailored to the referring site, for example having branding associated with the referring site.
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1. A system for initiating the enrollment of an electronic commerce card in an authentication program, the system comprising: an initial enrollment website; an activation link directing a cardholder system to the initial enrollment website; and an access control server directory including a directory of access control servers, each access control server associated with at least one of a plurality of card issuers; wherein the initial enrollment website is adapted to receive an enrollment request for an electronic commerce card from the cardholder system, to communicate the enrollment request to the access control server directory, to receive enrollment information from the access control server directory, and to redirect the cardholder system to a secondary enrollment website associated with the access control server associated with one of the plurality of card issuers providing the electronic commerce card in response to the enrollment information indicating the electronic commerce card is eligible for enrollment. 2. The system of claim 1, wherein the enrollment information includes an indication that the access control server associated with one of the plurality of card issuers providing the electronic commerce card supports the authentication program. 3. The system of claim 2, wherein the directory of access control servers includes for each access control server an indication of whether the access control server supports the authentication program. 4. The system of claim 1, wherein the activation link is provided by a merchant website. 5. The system of claim 4, wherein the initial enrollment site includes branding associated with the merchant website. 6. The system of claim 1, wherein the secondary activation website is adapted to collect authentication information from cardholder system. 7. The system of claim 1, wherein the enrollment request includes information identifying the one of the plurality of card issuers providing the electronic commerce card. 8. The system of claim 7, wherein the information identifying the one of the plurality of card issuers providing the electronic commerce card includes at least a portion of an electronic commerce card number. 9. The system of claim 1, wherein the access control server directory is adapted to query the access control server associated with one of the plurality of card issuers providing the electronic commerce card to determine if the electronic commerce card is eligible for enrollment in response to a determination that the one of the plurality of card issuers providing the electronic commerce card supports the authentication program and to receive a query response from the access control server associated with one of the plurality of card issuers providing the electronic commerce card. 10. The system of claim 9, wherein the access control server directory is adapted to communicate an enrollment request to an attempted enrollment access control server in response to a determination that the one of the plurality of card issuers providing the electronic commerce card does not supports the authentication program. 11. The system of claim 1, wherein the secondary activation website is adapted to return customer service information to the cardholder system. 12. A method for initiating the enrollment of an electronic commerce card in an authentication program, the method comprising: presenting an initial enrollment website to a cardholder system in response to the cardholder system selecting an activation link; receiving an enrollment request from the cardholder system; communicating the enrollment request to an access control server directory including a directory of access control servers, each access control server associated with at least one of a plurality of card issuers; receiving enrollment information from the access control server directory; and redirecting the cardholder to a secondary enrollment site associated with the access control server associated with one of the plurality of card issuers providing the electronic commerce card in response to the enrollment information indicating the electronic commerce card is eligible for enrollment. 13. The method of claim 12, wherein the enrollment information includes an indication that the access control server associated with one of the plurality of card issuers providing the electronic commerce card supports the authentication program. 14. The method of claim 13, wherein the directory of access control servers includes for each access control server an indication of whether the access control server supports the authentication program. 15. The method of claim 12, wherein the activation link is provided to the cardholder system by a merchant website. 16. The method of claim 15, wherein the initial enrollment site includes branding associated with the merchant website. 17. The method of claim 12, further including collecting authentication information from cardholder system using the secondary activation website. 18. The method of claim 12, wherein the enrollment request includes information identifying the one of the plurality of card issuers providing the electronic commerce card. 19. The method of claim 18, wherein the information identifying the one of the plurality of card issuers providing the electronic commerce card includes at least a portion of an electronic commerce card number. 20. The method of claim 12, further including: determining if the one of the plurality of card issuers providing the electronic commerce card supports the authentication program in response to the enrollment request; querying the access control server associated with one of the plurality of card issuers providing the electronic commerce card to determine if the electronic commerce card is eligible for enrollment in response in response to a determination that the one of the plurality of card issuers providing the electronic commerce card supports the authentication program; and receiving a query response from the access control server associated with one of the plurality of card issuers providing the electronic commerce card in response to the querying. 21. The method of claim 20, further including: communicating an enrollment request to an attempted enrollment access control server in response to a determination that the one of the plurality of card issuers providing the electronic commerce card does not supports the authentication program. 22. The method of claim 12, further including: returning customer service information to the cardholder system from the secondary activation website.
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CROSS-REFERENCES TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 60/484,927, entitled “Managing Activation of Cardholders in a Secure Authentication Program,” filed Jul. 2, 2003, which is incorporated by reference herein for all purposes. BACKGROUND OF THE INVENTION Electronic commerce cards are frequently used by consumers to make purchases from merchants over the Internet. Electronic commerce cards include credit cards, debit cards, prepaid purchase cards, travel cards, or any other system that can be used instead of cash to purchase goods or services. One example of an authentication system enables a cardholder to associate a password or other identifying information with an electronic commerce card. To make a purchase online, the consumer must provide the password or other identifying information associated with the electronic commerce card. This ensures that the person possessing the electronic commerce card is actually authorized to use the electronic commerce card. Electronic commerce card associations can encourage merchants to support authentication systems by offering more favorable terms to merchants for authenticated transactions. However, for an authentication system to be successful, it must be adopted by a large number of cardholders. Previously, card issuers have required unauthenticated cardholders to enroll in the authentication system, a procedure referred to as card activation, in order to complete a purchase. This requirement disrupts consumers' shopping process and can lead to lost sales for the merchant. Therefore, it is desirable to provide credit card associations, merchants, card issuers, and other parties with a system enabling cardholders to activate their cards at any convenient opportunity. It is further desirable that the system provides cardholders with a way to contact the card issuer for support. BRIEF SUMMARY OF THE INVENTION Merchants or other third parties can add an activation link on their Internet site. The activation link can be associated with text or an image, for example a logo. The activation link can be presented to cardholders visiting an Internet site prior to the cardholder initiating a transaction. Upon selecting the activation link, a cardholder is redirected to activation site. The activation site can be a generic site intended for any cardholder, or an activation site specifically tailored to the referring site, for example having branding associated with the referring site. In an embodiment, a system for initiating the enrollment of an electronic commerce card in an authentication program includes an initial enrollment website, an activation link directing a cardholder system to the initial enrollment website, and an access control server directory including a directory of access control servers. Each access control server is associated with at least one of a plurality of card issuers. The initial enrollment website is adapted to receive an enrollment request for an electronic commerce card from the cardholder system, to communicate the enrollment request to the access control server directory, and to receive enrollment information from the access control server directory. In response to the enrollment information indicating the electronic commerce card is eligible for enrollment, the initial enrollment website is further adapted to redirect the cardholder system to a secondary enrollment website associated with the access control server associated with one of the plurality of card issuers providing the electronic commerce card. In a further embodiment, the enrollment information includes an indication that the access control server associated with one of the plurality of card issuers providing the electronic commerce card supports the authentication program. The directory of access control servers may include for each access control server an indication of whether the access control server supports the authentication program. In an additional embodiment, the activation link is provided by a merchant website. The initial enrollment site may include branding associated with the merchant website. In another embodiment, the secondary activation website is adapted to collects authentication information from cardholder system. In a further embodiment, the secondary activation website is adapted to return customer service information to the cardholder system. In still another embodiment, the enrollment request includes information identifying the one of the plurality of card issuers providing the electronic commerce card. The information identifying the one of the plurality of card issuers providing the electronic commerce card includes at least a portion of an electronic commerce card number. In yet an additional embodiment, in response to a determination that the one of the plurality of card issuers providing the electronic commerce card supports the authentication program, the access control server directory is adapted to query the access control server associated with one of the plurality of card issuers providing the electronic commerce card to determine if the electronic commerce card is eligible for enrollment. Additionally, the access control server directory is adapted to receive a query response from the access control server associated with one of the plurality of card issuers providing the electronic commerce card. In a further embodiment, the access control server directory is adapted to communicate an enrollment request to an attempted enrollment access control server in response to a determination that the one of the plurality of card issuers providing the electronic commerce card does not supports the authentication program. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described with reference to the drawings, in which: FIG. 1 illustrates a prior decentralized card authentication system 100; and FIG. 2 illustrates a system enabling cardholders to activate their cards according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a prior decentralized card authentication system 100. System 100 enables cardholders to be authenticated when making electronic commerce card purchases online. Cardholder system 105 initiates an online purchase by accessing a merchant computer 110. In an embodiment, cardholder system 105 accesses a website provided by the merchant computer 110 via the Internet via a web browser. Alternatively, cardholder system 105 can access the merchant computer 110 via an alternate electronic communications network. The cardholder system 105 can be any type of communications device, for example a personal computer, a personal digital assistant, or a telephone. To complete a purchase, a cardholder uses the cardholder system 105 to submit her electronic commerce card information 150, such as a card number and expiration date, to the merchant system 110. In an embodiment, a secure communication system, such as SSL, is used for all communications, including the electronic commerce card information 150. In response to the electronic commerce card information 150, the merchant system initiates an authentication procedure to determine whether the electronic commerce card information is valid and has been provided by an authorized cardholder. In an embodiment of system 100, there are numerous electronic commerce card issuers. Each electronic commerce card issuer is responsible for authenticating its own electronic commerce cards. To authenticate the electronic commerce card information 150, the merchant system 110 must locate the authentication service of the electronic commerce card issuer associated with the electronic commerce card information 150. The merchant system sends a verifying enrollment request (VEReq) 152 to a directory server 120 to locate the appropriate authentication service. In an embodiment, all authentication-related communication is coordinated by an authentication plug-in 115 integrated with the merchant system 110. The VEReq 152 includes at least a portion of the electronic commerce card information 150 to be used by the directory server 120 to identify the authentication service associated with the cardholder's electronic commerce card. In an embodiment, each electronic commerce card issuer is assigned a different range of electronic commerce card numbers. This embodiment of the directory server 120 includes a list of all electronic commerce card issuers and their associated electronic commerce card number ranges. By comparing the electronic commerce card information with the list of electronic commerce card issuers, the directory server 120 is able to identify the appropriate authentication service. After identifying the authentication service, the directory server 120 forwards the VEReq 154 to an access control server (ACS) 125 associated with the card issuer's authentication service. The ACS 125 determines whether the card information provided in the VEReq 154 can be authenticated. Card information may not be able to be authenticated by the ACS 125 if, for example, the card information does not include a valid electronic commerce card number, or if there is no authentication information associated with the electronic commerce card number. If the electronic commerce card information provided in the VEReq 154 can be authenticated, the ACS 125 sends a verified enrollment response (VERes) 156 back to the directory server 120. The VERes 156 includes a message indicating that the ACS 125 can authenticate the electronic commerce card information and a pseudonym corresponding to the card number. The pseudonym can be any type of code or number that can be uniquely linked to card information by the ACS 125 at a later time. The VERes also includes a URL to be accessed by the cardholder system 105 to authenticate the cardholder. For system 100, the URL is associated with a web site provided by the ACS 125. Upon receiving a VERes from the ACS 125, the directory server 120 forwards the VERes 158 to the merchant system 110. From the received VERes, the merchant system 110 generates an authentication request. The authentication request includes the pseudonym created by the ACS 125 and transaction information associated with the cardholder's prospective purchase. The merchant system then forwards the authentication request 160 to the cardholder system 105. In an embodiment, the authentication request is sent to the cardholder system 105 with a web page having a redirection command, such as an HTTP redirect, to a web site hosted by the ACS 125. This web page also includes a URL for returning information to the merchant system 110. In response the authentication request received from the merchant system 110, the cardholder system 105 accesses 162 a web site hosted by the ACS 125. In accessing this web site, the cardholder system 105 supplies the ACS 125 with the pseudonym originally created by the ACS for the VERes. The cardholder to authenticates her identity by presenting authentication information 164 to the web site provided by the ACS 125. In an embodiment, the cardholder authenticates her identity by providing to the ACS 125 a password or other identifying information previously associated with the electronic commerce card. The ACS 125 uses the pseudonym provided by the cardholder system to identify the electronic commerce card being supplied by the cardholder and retrieve authentication information previously associated with the electronic commerce card. In an embodiment, the ACS 125 matches the pseudonym received via the authentication request 162 with the pseudonym previously created for VERes 156. In a further embodiment, the pseudonym expires after a limited period of time, for example five minutes, to prevent fraudulent reuse of the authentication request. The ACS 125 returns an authentication response 166 to the cardholder system 105. The cardholder system 105 in turn forwards the authentication response 168 to the merchant system 110. If the authentication information 164 provided by the cardholder matches the authentication information previously associated with the electronic commerce card, the authentication response includes a message indicating that the authentication was successful. Alternatively, the authentication response can include a message indicating that the authentication failed. In a further embodiment, the authentication response also includes an error code identifying the reason for authentication failure. In addition to sending the authentication response to the merchant system 110, a copy of the authentication response 167 is sent to an authentication history server 135. The authentication history server 135 maintains an archive of all authentications performed by the system 100. The authentication response is digitally signed to prevent the cardholder system 105 or other third party systems from tampering with the contents of the authentication response. After receiving the authentication response 168, the merchant system 110 validates the authentication response. To validate the authentication response 168, the merchant system 110 first verifies the digital signature associated with the authentication response to ensure that there has not been any tampering. Once the authentication response is determined to have arrived intact, and the response is for the request originally submitted, the contents of the authentication response are analyzed to determine if authentication has been successful. If the authentication was not successful, the merchant system 110 halts the transaction. If the authentication was successful, the merchant system 110 can continue with the transaction by initiating a charge to the electronic commerce card provided by the cardholder. In an embodiment, the merchant system 110 charges the electronic commerce card by submitting the card information to a card acquirer 144. The card acquirer then sends the charge request over a private card association network 148 to be processed by the electronic commerce card issuer associated with the card. In a further embodiment, an electronic commerce indicator and a Cardholder Authentication Verification Value, which indicates that the electronic commerce card has been successfully verified, is included with the charge request. FIG. 2 illustrates a system 200 enabling cardholders to activate their cards according to an embodiment of the invention. In this embodiment, a cardholder system 205 accesses 207 a merchant or other third party computer 210. In an embodiment, cardholder system 205 accesses 207 a website provided by the merchant computer 210 via the Internet via a web browser. Alternatively, cardholder system 205 can access 207 the merchant computer 210 via an alternate electronic communications network. The cardholder system 205 can be any type of communications device, for example a personal computer, a personal digital assistant, or a telephone. The merchant computer system 210 provides a hyperlink or other type of reference to the cardholder system 205. This hyperlink, referred to as an activation link, can be associated with text or an image, for example a logo. In an embodiment, the activation link can be presented to the cardholder system 205 visiting an Internet site prior to the cardholder system 105 initiating a transaction. For example, a merchant website can feature the activation link on its homepage. In an additional embodiment, the merchant system 210 can provide incentives to the cardholder to encourage the cardholder to initiate activation. Upon selecting the activation link, the cardholder system 205 is redirected 212 to an activation site 215. The activation site 215 can be a generic site intended for cardholder systems referred by any one of a plurality of unrelated merchant systems, including merchant system 210, or a site specifically tailored to the referring merchant site, for example having branding associated with the referring merchant site 210. The activation site 215 prompts the cardholder system 205 to enter all or a portion of their electronic commerce card number. This information 217 is returned to the activation site 215, where it is used to determine whether the electronic commerce card can be activated. In an embodiment, the card association includes a number of independently operating card issuers, each of which may or may not support the card associations authentication system. In this embodiment, an electronic commerce card can be activated if the card issuer responsible for issuing the electronic commerce card of the cardholder system 205 supports the card association's authentication system. To determine whether the card issuer supports the authentication system, an embodiment of the activation site 215 encrypts the information 217 into a verification request 219. The verification request 219 is forwarded to a card issuer directory server 220. The card issuer directory server 220 determines whether the access control server (ACS) associated with the card issuer supports the authentication system. In an embodiment, the directory server 220 maintains a listing of all of the ACS systems operating within the system 200 by the plurality of card issuers. In this example, ACS 225 is associated with the card issuer that issued the electronic commerce card used by the cardholder system 105. If the ACS 225 supports the authentication system, the ACS 225 is queried 227 by the directory server 220 to determine whether the electronic commerce card used by the cardholder system 205 is already activated or eligible for activation. The ACS 225 responds to the directory server's 220 query 227 with the electronic commerce card's enrollment information 229. If the electronic commerce card is eligible for activation and has not already activated, an embodiment of the enrollment information 229 includes a URL for initiating the activation process on the ACS 225. The directory server 220 forwards 231 the enrollment information to the activation site 215. The activation site 215 receives the enrollment information 231 from the card issuer directory server 220. If the electronic commerce card is eligible for activation and has not already activated, the activation site 215 uses the enrollment information 231 to redirect 233 the cardholder system 205 to a ACS activation site 235. The ACS activation site 235 collects a personal password and other account information 237 from the cardholder system 205 to verify the cardholder's identity and activate the electronic commerce card. The ACS activation site 235 accesses 239 the ACS 225 to verify the cardholder information and to record the activation information, such as a password, to be used to authenticate the cardholder's identity when they use the electronic commerce card for future purchases. In a further embodiment, if the card issuer directory server 220 determines that the ACS 225 associated with the card issuer does not support the authentication system, the directory server 220 queries 241 an Activation Attempt ACS 245. The Activation Attempt ACS 245 records the attempted activation request. A message informing the cardholder that activation is not supported by the card issuer is then returned to the cardholder system 205. In yet a further embodiment, the ACS activation site 235 associated with a card issuer can return contact information 247 for the card issuer to the cardholder system 205. The contact information 247 can include telephone numbers, e-mail addresses, and/or URLs for customer support. The contact information 247 can also include URLs for one or more customer support activities, such as updating an account password or accessing and updating account information. Further embodiments can be envisioned to one of ordinary skill in the art after reading the attached documents. In other embodiments, combinations or sub-combinations of the above disclosed invention can be advantageously made. The block diagrams of the architecture and flow charts are grouped for ease of understanding. However it should be understood that combinations of blocks, additions of new blocks, re-arrangement of blocks, and the like are contemplated in alternative embodiments of the present invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Electronic commerce cards are frequently used by consumers to make purchases from merchants over the Internet. Electronic commerce cards include credit cards, debit cards, prepaid purchase cards, travel cards, or any other system that can be used instead of cash to purchase goods or services. One example of an authentication system enables a cardholder to associate a password or other identifying information with an electronic commerce card. To make a purchase online, the consumer must provide the password or other identifying information associated with the electronic commerce card. This ensures that the person possessing the electronic commerce card is actually authorized to use the electronic commerce card. Electronic commerce card associations can encourage merchants to support authentication systems by offering more favorable terms to merchants for authenticated transactions. However, for an authentication system to be successful, it must be adopted by a large number of cardholders. Previously, card issuers have required unauthenticated cardholders to enroll in the authentication system, a procedure referred to as card activation, in order to complete a purchase. This requirement disrupts consumers' shopping process and can lead to lost sales for the merchant. Therefore, it is desirable to provide credit card associations, merchants, card issuers, and other parties with a system enabling cardholders to activate their cards at any convenient opportunity. It is further desirable that the system provides cardholders with a way to contact the card issuer for support.
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<SOH> BRIEF SUMMARY OF THE INVENTION <EOH>Merchants or other third parties can add an activation link on their Internet site. The activation link can be associated with text or an image, for example a logo. The activation link can be presented to cardholders visiting an Internet site prior to the cardholder initiating a transaction. Upon selecting the activation link, a cardholder is redirected to activation site. The activation site can be a generic site intended for any cardholder, or an activation site specifically tailored to the referring site, for example having branding associated with the referring site. In an embodiment, a system for initiating the enrollment of an electronic commerce card in an authentication program includes an initial enrollment website, an activation link directing a cardholder system to the initial enrollment website, and an access control server directory including a directory of access control servers. Each access control server is associated with at least one of a plurality of card issuers. The initial enrollment website is adapted to receive an enrollment request for an electronic commerce card from the cardholder system, to communicate the enrollment request to the access control server directory, and to receive enrollment information from the access control server directory. In response to the enrollment information indicating the electronic commerce card is eligible for enrollment, the initial enrollment website is further adapted to redirect the cardholder system to a secondary enrollment website associated with the access control server associated with one of the plurality of card issuers providing the electronic commerce card. In a further embodiment, the enrollment information includes an indication that the access control server associated with one of the plurality of card issuers providing the electronic commerce card supports the authentication program. The directory of access control servers may include for each access control server an indication of whether the access control server supports the authentication program. In an additional embodiment, the activation link is provided by a merchant website. The initial enrollment site may include branding associated with the merchant website. In another embodiment, the secondary activation website is adapted to collects authentication information from cardholder system. In a further embodiment, the secondary activation website is adapted to return customer service information to the cardholder system. In still another embodiment, the enrollment request includes information identifying the one of the plurality of card issuers providing the electronic commerce card. The information identifying the one of the plurality of card issuers providing the electronic commerce card includes at least a portion of an electronic commerce card number. In yet an additional embodiment, in response to a determination that the one of the plurality of card issuers providing the electronic commerce card supports the authentication program, the access control server directory is adapted to query the access control server associated with one of the plurality of card issuers providing the electronic commerce card to determine if the electronic commerce card is eligible for enrollment. Additionally, the access control server directory is adapted to receive a query response from the access control server associated with one of the plurality of card issuers providing the electronic commerce card. In a further embodiment, the access control server directory is adapted to communicate an enrollment request to an attempted enrollment access control server in response to a determination that the one of the plurality of card issuers providing the electronic commerce card does not supports the authentication program.
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20040702
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20060307
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20050210
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66771.0
| 0
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LABAZE, EDWYN
|
MANAGING ACTIVATION OF CARDHOLDERS IN A SECURE AUTHENTICATION PROGRAM
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UNDISCOUNTED
| 0
|
ACCEPTED
| 2,004
|
|||
10,885,064
|
ACCEPTED
|
Information writing device
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An information writing device in which the information can be written accurately efficiently and in which variable formats of the disc-shaped recording mediums can be coped with without the necessity of providing master discs from one format of the disc-shaped recording medium to another. A grating interferometer clock scale system is formed by a clock pattern disc 50 having a clock track 52 carrying an optically readable clock pattern 51 and an optical head 60 for optically reading out the clock pattern 51. Clock signals are generated in a clock generator 90, to which is transmitted, via an optical fiber 80, the interference light obtained as an optical output obtained in turn by optically reading out the clock pattern 51 by the optical head 60, based on electrical signals obtained on photoelectrically transducing the optical output. The servo information synchronized with the clock signals is generated by a servo information generating part 93.
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1. An information writing device comprising a spindle motor including a spindle shaft provided for protruding on a substrate for causing rotation of a disc-shaped recording medium detachably mounted on the spindle shaft; a clock pattern disc including a clock track in which an optically readable clock pattern is recorded along the entire circumference thereof, said clock pattern disc being mounted on said substrate on the proximal side of said spindle shaft and being run in rotation by said spindle motor; an optical head for optically reading out said clock pattern on said substrate; a clock generator for generating clock signals based on electrical signals obtained on photoelectrically transducing a light output transmitted via an optical fiber, said light output corresponding to said clock pattern optically read out by said optical head; an information generating part for generating the information in a timed relation to the clock signals generated by said clock generator; a recording head for writing the information generated by said information generating part on said disc-shaped recording medium, run in rotation by said spindle motor; head driving means for causing movement of said recording head in a direction along the radius of said disc-shaped recording medium; and position controlling means for controlling said head driving means based on the information generated by said information generating part for causing movement of said recording head to a preset position on said disc-shaped recording medium and positioning said recording head at said preset position. 2. The information writing device according to claim 1, wherein said clock pattern is a diffraction grating for diffracting an incident light beam; said optical head being formed by an interference optical system for detecting the intensity of interference of two homogeneous diffracted light beams contained in a diffracted light beam which is a light beam incident on and diffracted by said diffraction grating; said clock generator transducing changes in the intensity of interference of a light output, transmitted from said optical head through said optical fiber, into electrical signals, and generating the clock signals based on the generated electrical signals. 3. The information writing device according to claim 2, wherein said clock pattern is a reflection type diffractive grating for diffracting the incident light beam. 4. The information writing device according to claim 1 or 2, wherein a self-pulsation type semiconductor laser or a high-frequency-driven semiconductor laser is used as a light source of said light beam, the self-pulsation frequency or the frequency for high frequency driving is set so as to be higher than the frequency of an interference signal produced on rotation of said clock pattern disc, and wherein clock signals are generated based on a signal obtained on photoelectrically transducing said interference signal and removing modulation components by self-pulsation or high frequency driving by a low-pass filter from the resulting transduced signal. 5. The information writing device according to claim 1 or 2, wherein a windshield wall member having a window closed by a light transmitting material is provided on said substrate between the clock pattern disc and said optical head arranged facing said clock pattern disc. 6. The information writing device according to claim 1 or 2, wherein said clock generator transduces changes in the interference intensity of the light output transmitted from said optical head through said optical fiber into electrical signals by an avalanche photodetector. 7. The information writing device according to claim 1 or 2, wherein a pair of said optical heads are provided, a clock pattern is read out by said paired optical heads at diametrically opposite positions on the clock track of said clock pattern disc; and wherein said clock generator transduces changes in optical outputs, obtained on optically reading out said clock pattern by said paired optical heads, into respective electrical signals, to produce a pair of frequency signals, these paired frequency signals are mixed together to give a sum frequency signal, and clock signals are generated from the sum frequency signal.
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BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an information writing device for writing the information on a disc-shaped recording medium used on being mounted on a disc driving device. 2. Description of Related Art In a disc driving device, employing a disc-shaped recording medium, such as a hard disc, a flexible disc, an optical disc or a magneto-optical disc, a head is moved to a target track, based on the servo information written from the outset as the head positioning information on the disc-shaped recording medium, for correctly positioning the head by closed loop control. Conventionally, a so-called servo track writer, writing the servo information on a magnetic disc, such as a hard disc or a flexible disc, is designed and constructed so that the magnetic disc is rotated at a high speed by an air spindle motor, having a high axis shake precision, the magnetic head, loaded on a head slider, is positioned on the disc from track to track by a positioner employing a high precision scale, such as a laser encoder, the servo information is written by the magnetic head and, when the servo information for one round, that is, for one complete track, is written, the head slider is radially moved along the radius of the disc a distance corresponding to one prescribed track pitch, to write the servo information for the next track, and so on, until the servo information is written in the entire track. At this time, circumferential position detection is needed. The routine practice is to record clock signals on the disc by a separately provided magnetic head, to detect these clock signals and to re-record clock signals on the disc. For raising the servo information write efficiency, there has also been proposed, for a servo track writer in which a plural number of discs are stacked together, and the same plural number of heads, associated with the recording surfaces of the stacked discs, are provided for writing the servo information simultaneously on the recording surfaces of the discs, a method comprising providing a master disc, on which the servo information has been written to high precision, causing the rotation of the master disc and the discs, on which the servo information is to be written, by a spindle motor, as the master disc and the discs are stacked together, and to perform head positioning control based on the servo information read out from the master disc (see, for example, Cited Reference 1). [Cited Reference 1] Japanese Patent Application Laid-Open No. 2003-162874 Meanwhile, in the method employing the master disc, having the servo information recorded thereon to high precision, it is necessary to provide a master disc, free of defects, each time the disc format is changed. Moreover, crash of the master disc may be caused in the course of the information write operation. Moreover, the servo track writer is used in a clean room. Thus, if a magnetic clock head is used for reading out clock signals, crash of the magnetic head for clocks tends to be produced on deposition of dust and dirt on the surface of the clock head to contaminate the inside of the clean room. Recently, with the progress in the art of recording and/or reproduction, the tendency is towards a high density recording for the recording mediums, such that the clock frequency of data recorded on the disc-shaped recording medium is becoming higher. If, in order to raise the clock signal density further, the clock frequency of the data is increased, there may be presented the problem of unneeded radiation and signal attenuation in the transmission system of the servo information. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an information writing device of high universality by which the servo information can be written accurately and efficiently and which is able to cope with variable formats. It is another object of the present invention to provide an information writing device in which there is no risk of contamination of the inside of the clean room due to head crash and in which there may be presented no problem of unneeded radiation or signal attenuation in case the clock signal frequency has become higher. Other objects and advantages of the present invention will become more apparent from the following description of the preferred embodiment of the invention. An information writing device according to the present invention comprises a spindle motor including a spindle shaft provided for protruding on a substrate for causing rotation of a disc-shaped recording medium detachably mounted on the spindle shaft, a clock pattern disc including a clock track in which an optically readable clock pattern is recorded along the entire circumference thereof, with the clock pattern disc being mounted on the substrate on the proximal side of the spindle shaft and being run in rotation by the spindle motor, an optical head for optically reading out the clock pattern on the substrate, a clock generator for generating clock signals based on electrical signals obtained on photoelectrically transducing a light output transmitted via an optical fiber, with the light output corresponding to the clock pattern optically read out by the optical head, an information generating part for generating the information in a timed relation to the clock signals generated by the clock generator, a recording head for writing the information generated by the information generating part on the disc-shaped recording medium, run in rotation by the spindle motor, head driving means for causing movement of the recording head in a direction along the radius of the disc-shaped recording medium, and position controlling means for controlling the head driving means based on the information generated by the information generating part for causing movement of the recording head to a preset position on the disc-shaped recording medium and positioning the recording head at the preset position. With the information writing device, according to the present invention, a grating interferometer clock scale system is formed by a clock pattern disc having a clock track carrying an optically readable clock pattern extending along the entire circumference and an optical head for optically reading out the clock pattern. Clock signals are generated in a clock generator, to which is transmitted, via an optical fiber, the interference light obtained as an optical output obtained in turn by optically reading out the clock pattern by the optical head, based on electrical signals obtained on photoelectrically transducing the optical output. Hence, there is no fear of contamination of the inside of the clean room, ascribable to head crash, that may be produced with the use of the magnetic head. Moreover, there is presented on problem of unneeded radiation or signal attenuation in case the clock signal frequency has become higher. Since a clock disc of a large diameter, having a pattern with a large number of clocks per turn of the track, may be used, high-speed clock signals with a high resolution may be generated. The clock generator is able to generate clock signals of an optional frequency, over a wide frequency range, by e.g. the PLL, from the interference light, obtained as the optical output corresponding to the clock pattern optically read out by the optical head. The information of variable formats may be generated in timed relation to the clock signals, generated by the clock generator, such that variable formats may be accommodated, without providing master discs from one hard disc format to another. In writing the servo information, as the disc-shaped recording medium is run in rotation with the air spindle motor with a long axial length, the clock pattern disc may be mounted on the proximal end on the substrate of the spindle shaft of the spindle motor, the clock pattern disc may be mounted in the vicinity of the disc-shaped recording medium on which to write the information, so that it is possible to reduce the effect of the offset ascribable to the axis shake of the spindle motor to generate clock signals susceptible to only small jitter. In the clock generator, supplied with the interference light, corresponding to the optical output, which is the clock pattern optically read out by the optical head, the clock signals are generated on the basis of the electrical signals, obtained by photoelectrically transducing the optical output, there is presented no problem of unneeded radiations. Moreover, since there is no necessity of enclosing the photoelectric transducer, the optical head may be reduced in size. In addition, an avalanche photodetector, suffering from large power consumption and large heat evolution but having a high photoelectric transducing efficiency and superior frequency characteristics, may be used as a photoelectric transducing element. In the clock scale system of the grating interferometer system, formed by the clock pattern disc and the optical disc, on the substrate, an air flow is produced by high speed rotation of the clock pattern disc, and changes in the refractive index caused by changes in the density of air present between the clock pattern disc and the optical head represent a detection error. However, by providing a windshield wall member, having a window closed by the light transmitting material, on the substrate, between the clock pattern disc and the optical head, arranged facing the clock pattern disc, it is possible to prohibit the effect of the air current, otherwise caused by the high speed rotation of the clock pattern disc, thus allowing generation of clock signals highly accurately. The servo information, synchronized with the clock signals, generated by the clock generator, may be generated by the servo information generating unit and, based on this servo information, the recording head may be moved by position control means to a preset position on the recording medium, and may be positioned thereat to high accuracy, thus enabling the servo information, generated by the servo information generating unit, to be written accurately and speedily on the disc-shaped recording medium, rotationally driven at a high speed by the spindle motor. Moreover, a pair of the optical heads are provided, the clock pattern may be read out by the paired optical heads provided at diametrically opposite positions on the clock track of the clock pattern disc, and the clock generator transduces changes in the optical outputs corresponding to the clock pattern optically read out by the paired optical discs, to form a pair of frequency signals, which are then mixed together to generate a sum frequency signal. From this sum frequency signal, clock signals may be generated, whereby the effect of the offset of the spindle shaft may be counterbalanced to generate high precision clock signals. Thus, according to the present invention, there may be provided an information writing device of high universality in which the servo information can be written highly accurately and efficiently and in which variable formats can be accommodated without the necessity of providing master discs from one format of the disc-shaped recording medium to another. Moreover, according to the present invention, there may be provided an information writing device in which there is no fear of contamination of the inside of the clean room due to head crash and in which there is raised no problem of unneeded radiations or signal attenuation. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the structure of a servo track writer embodying the present invention. FIG. 2 is a schematic plan view of a clock pattern disc provided to the servo track writer. FIG. 3 is a schematic layout view of an interference optical system forming an optical head provided to the servo track writer. FIG. 4 is a perspective view showing the structure of a hard disc drive carrying a hard disc on which the servo information has been written by the servo track writer. FIG. 5 is a block diagram showing the structure of the servo track writer adapted for reading out a clock pattern on a clock track of a clock pattern disc by a pair of optical heads and for generating clock signals by a clock generator. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, a preferred embodiment of the present invention is explained in detail. The present invention is applied to a servo track writer 100 of a hard disc 1 configured as shown for example in FIG. 1. This servo track writer 100 includes a substrate 10, formed e.g. of stone or metal. An air spindle motor 20 for causing rotation of the hard disc 1, detachably mounted on a spindle shaft 21, a voice coil motor 40, as a head driving means, for causing movement of a magnetic head 31 for writing the servo information on the hard disc 1, in a direction along the radius of the hard disc 1, and a rotary positioner 45, forming a position controlling means for detecting and setting the position of the magnetic head 31 along the radius of the hard disc 1. The air spindle motor 20 is arranged so that the spindle shaft 21 thereof is protruded above the substrate 10. On this spindle shaft 21 of the air spindle motor 20, a plural number of hard discs 1 are detachably mounted as a disc stack 5 comprised of the hard discs 1 layered together by a hub 22 with a preset interval between the neighboring discs. The air spindle motor 20 causes high-speed rotation in unison of plural hard discs 1, loaded as the disc stack 5 on the spindle shaft 21. The servo track writer 100 includes a head stack 30, comprised of a plural number of the magnetic heads 31 unified together with a preset separation between the neighboring magnetic heads 31 in association with the hard discs 1. This head stack 30 is rotationally displaced by the voice coil motor 40 for causing movement of the magnetic heads 31 in the radial direction on the recording surface of the hard disc 1. The rotary positioner 45 is comprised of a rotary encoder, not shown, employing e.g. the laser light, for detecting the rotational angular position of the voice coil motor 40. From the rotational angular position of the voice coil motor 40, a detection output, indicating the position of the magnetic head 31 along the radius of the hard disc1 is obtained. A clock pattern disc 50 is mounted to the proximal portion of the spindle shaft 21 on the substrate 10 in the air spindle motor 20 of the servo track writer 100. This clock pattern disc 50 is run in rotation at a high speed along with the plural hard discs 1 mounted on the spindle shaft 21. The clock pattern disc 50 includes a clock track 52 having circumferentially recorded thereon a clock pattern 51 that may be read out optically, as shown in FIG. 2. The clock pattern 51 is comprised of a reflection type diffraction grating configured for diffracting an incident light beam. The clock pattern disc 50 may be made detachable along with the disc stack 5. The servo track writer 100 includes an optical head 60 for optically reading out the clock pattern 51 on the substrate 10. This optical head 60 is mounted facing a clock track 52 of the clock pattern disc 50 on the substrate 10, and is mounted on the substrate 10 or a casing 25 of the spindle motor 20 either directly or via a mounting plate 70. In the present embodiment, the optical head 60 is secured to the casing 25 of the spindle motor 20 via mounting plate 70. In this servo track writer 100, a windshield wall member 72, having a window 71 closed with a light-transmitting material, is provided between the clock pattern disc 50 and the optical head 60. The optical head 60 is formed by an interference optical system, configured as shown in FIG. 3 for detecting the intensity of interference of two order-one diffracted light beams contained in the reflected light of a light beam which is incident on and refracted by the clock pattern 51, that is, the reflection type refractive grating. Meanwhile, it is sufficient that the diffractive light, detected for the intensity of interference, is two homogeneous directed light beams, such that it may be two order-two diffracted light beams. That is, the optical head 60 includes a polarizing beam splitter 63, on which is incident the laser beam radiated from a semiconductor laser 61 through a converging lens 62, reflective mirrors 64A, 64B, reflecting two polarized light components P and S, separated by the polarizing beam splitter 63, to cause the reflected polarized light components to fall on the clock pattern 51, that is, on the reflection type diffractive grating, and reflective mirrors 66A, 66B on which fall the reflected light beams by the reflection type diffractive grating through λ/4 plates 65A, 65B. The reflected light beams from the reflective mirrors 66A, 66B proceed along the same optical path as the ongoing optical path but in the opposite direction so as to be returned as rotated light beams to the polarizing beam splitter 63. The light beams of respective different directions of light polarization, incident on the reflection type diffractive grating, are reflected and diffracted by the reflection type diffractive grating to become the diffracted light beams of the same sign different in the direction of light polarization. These diffracted light beams are returned as light beams, rotated in the direction of light polarization by 90° from the state of the ongoing light, by the λ/4 plates 65A, 65B and the reflective mirrors 66A, 66B, to the polarizing beam splitter 63, where the light beams are mixed together. The return light beams, returned to the polarizing beam splitter 63, are rotated 90° in the directions of polarization thereof, so that, if the light beams are radiated in a direction at right angles to the light incident direction on the ongoing optical path and the polarized light components of the same direction are taken out by the light polarizing plate 67, light interference is produced. The interference light falls on an optical fiber 80 through converging lens 68. If the wavelength λ, amplitude E and the vector of the number of light waves of the incident light k are related with one another by E=2ei(kr+wt) k=2πλ, the wavelength of the grating Λ, transmittance T and the vector of the grating K of the reflection type diffractive grating are such that transmittance T=1+cos(Kx) vector of the grating K=2π/Λ, the two order-one diffracted light beams E1, E1′ by the reflection type diffractive grating are represented by E1=ei(kr+wt+Kx) E1′=ei(kr+wt−Kx) while the intensity I of the interfering light of the two order-one diffracted light beams E1, E1′ is given by I = ( E1 ′ + E1 ) ( E1 ′ + E1 ) * = 2 + 2 cos ( 2 Kx + Φ ) where Φ is a constant phase term. If the interference light intensity I is observed, one sine wave signal is obtained for the distance of movement equal to ½ of the grating wavelength Λ of the reflection type diffractive grating. In the interference optical system, employed in the optical head 60 in this servo track writer 100, since the diffraction occurs twice by the reflection type diffractive grating, that is, once on the ongoing path and on the return path, one sine wave signal is obtained for the distance of movement equal to one-fourth of the grating wavelength Λ of the reflection type diffractive grating. As the semiconductor laser 61, the type of the laser in which the longitudinal mode is the multimode and the distance of coherence is short, or the laser type in which the longitudinal mode is inherently a single mode but is turned into a multi-mode by high frequency modulation of the driving current (referred to below as high frequency driving), may be used. In case the semiconductor laser, in which the longitudinal mode is the single mode, is used, skipping of the interference signals or noise generation due to mode whip tends to be produced. Such problem is not raised with the multi-mode semiconductor laser because no mode whip is produced. With the single-mode semiconductor laser, with a long distance of coherence, the noise tends to be produced in the interference signal due to interference of the light subjected to multiple reflection. With the multi-mode semiconductor laser, no such problem is raised because of the short distance of coherence. On the other hand, as disclosed in the Japanese Laid-Open Patent Publication 61-83911, if there is a difference in the optical path lengths of two light beams, interfering with each other, an error E such that E=Δλ/λ·2·ΔL·Λ/4 where λ denotes the wavelength of the light source, ΔL denotes the difference of the optical path lengths, Δλ is the wavelength variation and Λ is produced. If the distance of coherence is short, the difference of the optical path lengths ΔL of the two light beams, interfering with each other, may be reduced, and hence the error generation in the clock signal caused by laser wavelength variation may be diminished. If the semiconductor laser in which the single mode type of the longitudinal mode is turned into a multi-mode by high frequency driving, the above-described merits may be derived. In this case, the light beam is in the intensity modulated form, and hence the frequency of high pulsation or high frequency driving is desirably not less than twice the frequency of the interference signal obtained on disc rotation. The superposed signal needs to be removed by a low-pass filter after photoelectrically transducing the interference signal. The servo track writer 100 also includes a clock generator 90, to which an optical output corresponding to the clock pattern 51 optically read out by the optical head 60 is transmitted over the optical fiber 80, a servo information generator 93, supplied with the clock signals generated by the clock generator 90, a VCM controller 94, and a servo information write unit 95, supplied with the servo information generated by the servo information generator 93. The clock generator 90 transduces changes in the interference intensity of the optical output, supplied from the optical head 60 through the optical fiber 80, by a photodetector 91, into electrical signals, serving as frequency signals, based on which clock signals are generated by a clock generator 92. As the photodetector 91, an avalanche photodetector is used. The clock generator 92 is able to generate clock signals of an optional frequency based on electrical signals obtained on photoelectrically tranducing the optical output by the photodetector 91. The servo information generator 93 generates the servo information in timed relation to the clock signals generated by the clock generator 90. The VCM controller 94 is supplied from the rotary positioner 45 with a detection output, indicating the position of the magnetic head 31, along the radial direction of the hard disc 1, and controls the voice coil motor 40, based on the detection output, indicating the position of the magnetic head 31, and on the servo information generated by the servo information generator 93, to cause movement of the magnetic head 31 to a track position on the hard disc 1 for writing the servo information by the magnetic head 31, that is, to a preset position along the radial direction of the hard disc 1. The servo information write unit 95 sends the servo information, generated by the servo information generator 93, as a recording signal to each magnetic head 31, for writing the so generated servo information on each hard disc. In the above-described servo track writer 100, in which no magnetic head is used, there is no fear of contamination of the inside of the clean room otherwise caused by head crash. Moreover, since the clock signals are transmitted as optical signals, using the optical fiber 80, there is no fear of raising the problem of unneeded radiations or signal attenuation, such that the clock pattern disc 50 of a larger diameter, having a clock pattern composed of a large number of clocks per turn, thus enabling the generation of high resolution high speed clocks. Additionally, with the clock generator 90, it is possible to generate clock signal of an optional frequency, over a wide frequency range, by e.g. the PLL, from the interference light obtained as a light output corresponding to the aforementioned clock pattern 51 optically read out by the optical head 60. Furthermore, the clock pattern disc 50 of a larger diameter may be used, so that, when the hard disc 1 is run in rotation by the air spindle motor 20 of a larger axial length, the clock pattern disc 50 may be mounted on the substrate 10 in the vicinity of the hard disc 1, on which to write the servo information, by mounting the clock pattern disc 50 on the proximal end of the spindle shaft 21 of the air spindle motor 20, thereby reducing the effect of the offset caused by axis shake of the spindle motor 20 to a minimum to enable generation of clock signals with reduced jitter. Since the interference light, obtained as an optical output, corresponding to the clock pattern 51 optically read out by the optical head 60, is transmitted through the optical fiber 80, there is raised no problem of, for example, unneeded radiations. Moreover, since there is no necessity for enclosing the photoelectric transducer, the optical head 60 may be reduced in size. On the other hand, a photoelectric transducer, such as an avalanche photodetector, suffering from large power consumption and large heat evolution but having a high photoelectric transducing efficiency and superior frequency characteristics, may be used as the photodetector 91. In the clock scale system of the grating interferometer system, formed by the clock pattern disc 50 and the optical disc 60, on the substrate 10, an air flow is produced by high speed rotation of the clock pattern disc 50, changes in the refractive index by the changes in the density of air present between the clock pattern disc 50 and the optical head 60 represent a detection error. However, by providing a windshield wall member 72, having a window 71 closed by the light transmitting material, on the substrate, between the clock pattern disc 50 and the optical head 60, arranged facing the clock pattern disc 50, it is possible to prohibit the effect of the air current caused by the high speed rotation of the clock pattern disc 50 to generate clock signals highly accurately. Meanwhile, in case the diffraction grating is of the transmitting type, it is preferred to provide a windshield wall member 72 having a window 71 on each surface of the clock pattern disc 50. For further reducing the effect of the air flow, the side of the window 71 facing the clock pattern disc 50 is preferably flush with the windshield wall member 72. This windshield wall member 72 is preferably formed along the entire circumference of the clock pattern disc 50. In case the diffraction grating is of the transmitting type, the windshield wall member 72 preferably overlies the clock pattern disc 50. Although the separation between the windshield wall member 72 and the clock pattern disc 50 may approximately be 20 mm or less, it is preferably 10 mm or less if the signals of the optical system are taken into account. The servo information, synchronized with the clock signals, generated by the clock generator 90, may be generated by the servo information generator 93 and, by controlling the voice coil motor 40, by the VCM controller 94, based on this servo information, the recording head 31 may be moved to a preset position on the recording medium and positioned to high accuracy, thus enabling the accurate and quick writing of the servo information, generated by the servo information generator 93, on the hard disc 1, rotationally driven at a high speed by the spindle motor 20. The hard disc 1, on which has been written the servo information by the servo track writer 100, is loaded on a hard disc drive 110 configured as shown for example in FIG. 4. With this hard disc drive 110, the hard disc 1 is run in rotation by a spindle motor 111, and the information is recorded and/or reproduced by a magnetic head 112. The magnetic head 112 is moved radially of the hard disc 1 by a voice coil motor 113. With the above-described servo track writer 100, the clock pattern 51 on the clock track 52 of the clock pattern disc 50 is read out and clock signals are generated by the clock generator 90. Alternatively, the clock pattern 51 on the clock track 52 of the clock pattern disc 50 may be read out by a pair of optical heads 60A, 60B, to generate clock signals by the clock generator 90, as in a servo track writer 200 shown in FIG. 5. Meanwhile, in the servo track writer 200, shown in FIG. 5, the parts or components which are the same as those of the servo track writer 100 shown in FIG. 1 are indicated by the same reference numerals, and the detailed description thereof is omitted for simplicity. In the servo track writer 200, shown in FIG. 5, a pair of optical heads 60A, 60B are mounted at diametrically opposite positions on the clock track 52 of the clock pattern disc 50, for reading out the clock pattern 51 via windows 71A, 71B of the windshield wall member 72. The clock pattern 51 is optically read out at the diametrically opposite positions on the clock track 52 by the paired optical heads 60A, 60B to generate optical outputs which are transmitted via optical fibers 80A, 80B so as to be incident on the clock generator 90. A pair of photoconductors 91A, 91B of the clock generator 90 operate for transducing changes in the optical outputs corresponding to the clock pattern 51 optically read out by the paired optical heads 60A, 60B, into electrical signals to form a pair of frequency signals, which are then mixed together by a mixer 91C to generate a sum frequency signal. From this sum frequency signal, clock signals are generated by a clock generating circuit 92 to generate clock signals. In this manner, the clock pattern 51 is read out at diametrically opposite positions on the clock track 52 of the clock pattern disc 50. The clock generator 90 operate for transducing changes in the optical output, optically read out by the paired optical heads 60A, 60B, into electrical signals to form a pair of frequency signals, which are then mixed together to form a sum frequency signal, From this sum frequency signal, clock signals are generated, whereby the effect of the offset of the spindle shaft 21 may be counterbalanced to generate high precision clock signals. Although the present invention has been applied to the servo track writer 100, adapted for writing the servo information on the hard disc 1, the present invention may also be applied to a cutting device adapted for producing a master disc of an optical disc or a magneto-optical disc. Although a reflection type diffractive grating is referred to in the explanation of the above-described embodiment, a transmission type diffractive grating may also be used. Although the above-described embodiment refers to the servo track writer 100, configured for writing the servo information on the hard disc 1, data as information may also be written on the disc-shaped recording medium.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention This invention relates to an information writing device for writing the information on a disc-shaped recording medium used on being mounted on a disc driving device. 2. Description of Related Art In a disc driving device, employing a disc-shaped recording medium, such as a hard disc, a flexible disc, an optical disc or a magneto-optical disc, a head is moved to a target track, based on the servo information written from the outset as the head positioning information on the disc-shaped recording medium, for correctly positioning the head by closed loop control. Conventionally, a so-called servo track writer, writing the servo information on a magnetic disc, such as a hard disc or a flexible disc, is designed and constructed so that the magnetic disc is rotated at a high speed by an air spindle motor, having a high axis shake precision, the magnetic head, loaded on a head slider, is positioned on the disc from track to track by a positioner employing a high precision scale, such as a laser encoder, the servo information is written by the magnetic head and, when the servo information for one round, that is, for one complete track, is written, the head slider is radially moved along the radius of the disc a distance corresponding to one prescribed track pitch, to write the servo information for the next track, and so on, until the servo information is written in the entire track. At this time, circumferential position detection is needed. The routine practice is to record clock signals on the disc by a separately provided magnetic head, to detect these clock signals and to re-record clock signals on the disc. For raising the servo information write efficiency, there has also been proposed, for a servo track writer in which a plural number of discs are stacked together, and the same plural number of heads, associated with the recording surfaces of the stacked discs, are provided for writing the servo information simultaneously on the recording surfaces of the discs, a method comprising providing a master disc, on which the servo information has been written to high precision, causing the rotation of the master disc and the discs, on which the servo information is to be written, by a spindle motor, as the master disc and the discs are stacked together, and to perform head positioning control based on the servo information read out from the master disc (see, for example, Cited Reference 1). [Cited Reference 1] Japanese Patent Application Laid-Open No. 2003-162874 Meanwhile, in the method employing the master disc, having the servo information recorded thereon to high precision, it is necessary to provide a master disc, free of defects, each time the disc format is changed. Moreover, crash of the master disc may be caused in the course of the information write operation. Moreover, the servo track writer is used in a clean room. Thus, if a magnetic clock head is used for reading out clock signals, crash of the magnetic head for clocks tends to be produced on deposition of dust and dirt on the surface of the clock head to contaminate the inside of the clean room. Recently, with the progress in the art of recording and/or reproduction, the tendency is towards a high density recording for the recording mediums, such that the clock frequency of data recorded on the disc-shaped recording medium is becoming higher. If, in order to raise the clock signal density further, the clock frequency of the data is increased, there may be presented the problem of unneeded radiation and signal attenuation in the transmission system of the servo information.
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<SOH> SUMMARY OF THE INVENTION <EOH>It is therefore an object of the present invention to provide an information writing device of high universality by which the servo information can be written accurately and efficiently and which is able to cope with variable formats. It is another object of the present invention to provide an information writing device in which there is no risk of contamination of the inside of the clean room due to head crash and in which there may be presented no problem of unneeded radiation or signal attenuation in case the clock signal frequency has become higher. Other objects and advantages of the present invention will become more apparent from the following description of the preferred embodiment of the invention. An information writing device according to the present invention comprises a spindle motor including a spindle shaft provided for protruding on a substrate for causing rotation of a disc-shaped recording medium detachably mounted on the spindle shaft, a clock pattern disc including a clock track in which an optically readable clock pattern is recorded along the entire circumference thereof, with the clock pattern disc being mounted on the substrate on the proximal side of the spindle shaft and being run in rotation by the spindle motor, an optical head for optically reading out the clock pattern on the substrate, a clock generator for generating clock signals based on electrical signals obtained on photoelectrically transducing a light output transmitted via an optical fiber, with the light output corresponding to the clock pattern optically read out by the optical head, an information generating part for generating the information in a timed relation to the clock signals generated by the clock generator, a recording head for writing the information generated by the information generating part on the disc-shaped recording medium, run in rotation by the spindle motor, head driving means for causing movement of the recording head in a direction along the radius of the disc-shaped recording medium, and position controlling means for controlling the head driving means based on the information generated by the information generating part for causing movement of the recording head to a preset position on the disc-shaped recording medium and positioning the recording head at the preset position. With the information writing device, according to the present invention, a grating interferometer clock scale system is formed by a clock pattern disc having a clock track carrying an optically readable clock pattern extending along the entire circumference and an optical head for optically reading out the clock pattern. Clock signals are generated in a clock generator, to which is transmitted, via an optical fiber, the interference light obtained as an optical output obtained in turn by optically reading out the clock pattern by the optical head, based on electrical signals obtained on photoelectrically transducing the optical output. Hence, there is no fear of contamination of the inside of the clean room, ascribable to head crash, that may be produced with the use of the magnetic head. Moreover, there is presented on problem of unneeded radiation or signal attenuation in case the clock signal frequency has become higher. Since a clock disc of a large diameter, having a pattern with a large number of clocks per turn of the track, may be used, high-speed clock signals with a high resolution may be generated. The clock generator is able to generate clock signals of an optional frequency, over a wide frequency range, by e.g. the PLL, from the interference light, obtained as the optical output corresponding to the clock pattern optically read out by the optical head. The information of variable formats may be generated in timed relation to the clock signals, generated by the clock generator, such that variable formats may be accommodated, without providing master discs from one hard disc format to another. In writing the servo information, as the disc-shaped recording medium is run in rotation with the air spindle motor with a long axial length, the clock pattern disc may be mounted on the proximal end on the substrate of the spindle shaft of the spindle motor, the clock pattern disc may be mounted in the vicinity of the disc-shaped recording medium on which to write the information, so that it is possible to reduce the effect of the offset ascribable to the axis shake of the spindle motor to generate clock signals susceptible to only small jitter. In the clock generator, supplied with the interference light, corresponding to the optical output, which is the clock pattern optically read out by the optical head, the clock signals are generated on the basis of the electrical signals, obtained by photoelectrically transducing the optical output, there is presented no problem of unneeded radiations. Moreover, since there is no necessity of enclosing the photoelectric transducer, the optical head may be reduced in size. In addition, an avalanche photodetector, suffering from large power consumption and large heat evolution but having a high photoelectric transducing efficiency and superior frequency characteristics, may be used as a photoelectric transducing element. In the clock scale system of the grating interferometer system, formed by the clock pattern disc and the optical disc, on the substrate, an air flow is produced by high speed rotation of the clock pattern disc, and changes in the refractive index caused by changes in the density of air present between the clock pattern disc and the optical head represent a detection error. However, by providing a windshield wall member, having a window closed by the light transmitting material, on the substrate, between the clock pattern disc and the optical head, arranged facing the clock pattern disc, it is possible to prohibit the effect of the air current, otherwise caused by the high speed rotation of the clock pattern disc, thus allowing generation of clock signals highly accurately. The servo information, synchronized with the clock signals, generated by the clock generator, may be generated by the servo information generating unit and, based on this servo information, the recording head may be moved by position control means to a preset position on the recording medium, and may be positioned thereat to high accuracy, thus enabling the servo information, generated by the servo information generating unit, to be written accurately and speedily on the disc-shaped recording medium, rotationally driven at a high speed by the spindle motor. Moreover, a pair of the optical heads are provided, the clock pattern may be read out by the paired optical heads provided at diametrically opposite positions on the clock track of the clock pattern disc, and the clock generator transduces changes in the optical outputs corresponding to the clock pattern optically read out by the paired optical discs, to form a pair of frequency signals, which are then mixed together to generate a sum frequency signal. From this sum frequency signal, clock signals may be generated, whereby the effect of the offset of the spindle shaft may be counterbalanced to generate high precision clock signals. Thus, according to the present invention, there may be provided an information writing device of high universality in which the servo information can be written highly accurately and efficiently and in which variable formats can be accommodated without the necessity of providing master discs from one format of the disc-shaped recording medium to another. Moreover, according to the present invention, there may be provided an information writing device in which there is no fear of contamination of the inside of the clean room due to head crash and in which there is raised no problem of unneeded radiations or signal attenuation.
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20040707
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20061114
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20050217
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86384.0
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GIESY, ADAM
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INFORMATION WRITING DEVICE
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UNDISCOUNTED
| 0
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ACCEPTED
| 2,004
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10,885,236
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ACCEPTED
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Method and apparatus for calibrating an interactive touch system
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A method of calibrating an interactive touch system includes moving a pointer along at least one path on a touch surface over a calibration image presented on the touch surface. Pointer coordinates are generated generally continuously during the tracing representing pointer contact locations on the touch surface. The coordinate system of the touch surface is mapped to the coordinate system of the calibration image using the pointer coordinates and the calibration image.
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1. A method of calibrating an interactive touch system comprising: moving a pointer along at least one path on a touch surface over a calibration image presented on said touch surface; generating pointer coordinates generally continuously during pointer movement representing pointer contact locations on said touch surface; and mapping the coordinate system of the touch surface to the coordinate system of the calibration image using said pointer coordinates and said calibration image. 2. The method of claim 2 wherein said calibration image includes at least one demarcation providing visual guidance with respect to said at least one path along which said pointer is to be moved. 3. The method of claim 2 wherein said demarcation is at least one line to be traced using said pointer. 4. The method of claim 3 wherein said at least one line is straight. 5. The method of claim 4 wherein said calibration image includes a plurality of straight lines visually identifying said at least one path to be traced using said pointer. 6. The method of claim 5 wherein said plurality of straight lines are joined to form at least one geometric shape. 7. The method of claim 6 wherein said plurality of straight lines form a single geometric shape. 8. The method of claim 7 wherein said straight lines follow the perimeter of said calibration image. 9. The method of claim 6 wherein said at least one geometric shape is within the boundary of said calibration image. 10. The method of claim 9 wherein said plurality of straight lines form multiple geometric shapes. 11. The method of claim 10 wherein said multiple geometric shapes are concentric. 12. The method of claim 5 wherein at least some of said straight lines are isolated. 13. The method of claim 12 wherein all of said straight lines are isolated. 14. The method of claim 13 wherein said straight lines are generally parallel. 15. The method of claim 5 wherein at least some of said straight lines intersect. 16. The method of claim 15 wherein all of said straight lines intersect. 17. The method of claim 3 wherein said at least one line is curved. 18. The method of claim 17 wherein said at least one curved line is within the boundary of said calibration image. 19. The method of claim 18 wherein said at least one curved line forms at least one closed loop. 20. The method of claim 19 wherein the entire curved line forms a closed loop. 21. The method of claim 19 wherein said at least one curved line forms a plurality of closed loops along its length. 22. The method of claim 2 wherein said at least one tracing path is defined by the space between spaced lines. 23. The method of claim 22 wherein said spaced lines form a maze, said at least one tracing path being defined by the solution to said maze. 24. The method of claim 23 wherein said maze has a single solution. 25. The method of claim 23 wherein said maze has multiple solutions. 26. The method of claim 2 wherein said demarcation is presented in said calibration image after pointer contact with said touch surface, said demarcation representing the end point of said at least one path. 27. The method of claim 2 further comprising generating a calibrated touch surface coordinate system using said mapping. 28. The method of claim 27 further comprising storing said calibrated touch surface coordinate system in memory. 29. The method of claim 28 wherein said at least one demarcation visually identifies at least one path to be traced using said pointer, the coordinates of the demarcation in the calibration image coordinate system being used during said mapping. 30. The method of claim 29 wherein pointer coordinates corresponding to at least one discrete point along said at least one tracing path is extracted and used to enhance said mapping. 31. The method of claim 30 wherein said at least one discrete point includes at least one of the start and end points of the tracing path. 32. The method of claim 31 wherein said at least one tracing path is shaped to define at least one discrete point intermediate the start and end points of the tracing path. 33. The method of claim 32 wherein said at least one tracing path includes at least one intersection point defining said at least one intermediate discrete point. 34. The method of claim 32 wherein said at least one tracing path includes at least one inflection point defining said at least one intermediate discrete point. 35. The method of claim 29 wherein said at least one tracing path is complex, during said mapping the slope of at least a portion of said traced path being calculated using said pointer coordinates to enhance said mapping. 36. The method of claim 35 wherein pointer coordinates corresponding to at least one discrete point along said at least one tracing path is extracted and used to enhance said mapping. 37. The method of claim 36 wherein said at least one discrete point includes at least one of the start and end points of the tracing path. 38. The method of claim 37 wherein said at least one tracing path is shaped to define at least one discrete point intermediate the start and end points of the tracing path. 39. The method of claim 38 wherein said at least one tracing path includes at least one intersection point defining said at least one intermediate discrete point. 40. The method of claim 38 wherein said at least one tracing path includes at least one inflection point defining said at least one intermediate discrete point. 41. The method of claim 27 further comprising providing feedback during tracing indicating the degree of calibration of said calibrated touch surface coordinate system. 42. The method of claim 41 wherein said feedback is visual. 43. The method of claim 42 wherein said visual feedback is a highlighted path provided in said calibration image representing the perceived path of said pointer in said calibration image coordinate system. 44. The method of claim 43 wherein said at least one tracing path is complex, during said mapping the slope of at least a portion of said traced path being calculated using said pointer coordinates to enhance said mapping. 45. The method of claim 44 wherein pointer coordinates corresponding to at least one discrete point along said at least one tracing path is extracted and used to enhance said mapping. 46. The method of claim 45 wherein said at least one discrete point includes at least one of the start and end points of the tracing path. 47. The method of claim 46 wherein said at least one tracing path is shaped to define at least one discrete point intermediate the start and end points of the tracing path. 48. The method of claim 47 wherein said at least one tracing path includes at least one intersection point defining said at least one intermediate discrete point. 49. The method of claim 47 wherein said at least one tracing path includes at least one inflection point defining said at least one intermediate discrete point. 50. The method of claim 43 wherein said tracing continues until said highlighted path corresponds generally to the at least one demarcation. 51. The method of claim 29 further comprising displaying textual directions in said calibration image. 52. The method of claim 43 further comprising displaying textual directions in said calibration image. 53. A method of calibrating an interactive touch system comprising: displaying a calibration image on a touch surface, said calibration image specifying at least one path to be traced using a pointer; moving the pointer along the specified at least one tracing path; generating pointer coordinates generally continuously during said tracing representing pointer contact locations on said touch surface; mapping the coordinate system of the touch surface to the coordinate system of the calibration image using said pointer coordinates and said calibration image to calibrate the touch surface coordinate system; and providing feedback indicating the degree of calibration between the touch surface coordinate system and the calibration image coordinate system. 54. The method of claim 53 wherein said feedback is visual. 55. The method of claim 54 wherein during said feedback providing, a highlighted path is provided in said calibration image representing the perceived path of said pointer in said calibration image coordinate system. 56. The method of claim 55 wherein said moving continues until said highlighted path corresponds generally to the specified at least one path in said calibration image. 57. The method of claim 55 further comprising displaying textual directions in said calibration image. 58. A touch system comprising: a touch screen having a surface on which pointer contacts are made, said touch screen generating pointer coordinates in response to pointer contacts thereon; a computing device coupled to said touch screen and receiving pointer coordinates generated thereby; and a projection device coupled to said computing device, said projection device receiving display output from said computing device and projecting an image that is presented on said surface, wherein said computing device is operable to perform a calibration process, during said calibration process said computing device: providing display output to said projection device causing said projection device to project a calibration image on said surface, said calibration image being within the boundary of said surface and including at least one visual demarcation providing a guide with respect to at least one path a pointer is to be moved across said surface; receiving the pointer coordinates during movement of said pointer along said at least one path; and processing the pointer coordinates using the calibration image to map the touch screen coordinate system to the display output coordinate system thereby to calibrate said touch system. 59. A touch system according to claim 59 wherein said computing device updates the calibration image to provide visual feedback of the perceived path of said pointer in the display output coordinate system. 60. A touch system according to claim 58 wherein said calibration image specifies at least one line to be traced using said pointer. 61. A touch system according to claim 60 wherein said at least one line undergoes at least one change in direction. 62. A touch system according to claim 61 wherein said at least one line is complex. 63. A touch system according to claim 58 wherein said surface is generally planar. 64. A touch system according to claim 58 wherein said surface is non-planar. 65. A touch system according to claim 58 wherein said surface is irregular.
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FIELD OF THE INVENTION The present invention relates generally to interactive touch systems and in particular to a method and apparatus for calibrating an interactive touch system. BACKGROUND OF THE INVENTION Interactive touch systems are well known in the art and typically include a touch screen having a touch surface on which contacts are made using a pointer in order to generate user input. Pointer contacts with the touch surface are detected and are used to generate corresponding output based on the locations of contact. There are basically two general types of touch systems available and they can be broadly classified as “active” touch systems and “passive” touch systems. Interactive touch systems have a number of applications relating to computer operation and video display. For example, U.S. Pat. No. 5,448,263 to Martin, assigned to SMART Technologies Inc., assignee of the present invention, discloses a passive touch system including a touch screen coupled to a computer. The computer display is projected on to the touch surface of the touch screen via an imaging device such as a projector. The coordinates representing specific locations on the touch surface are mapped to the coordinate system of the computer display. When a user contacts the touch surface of the touch screen, coordinate data is generated by the touch screen and fed to the computer. The computer maps the received coordinate data to the computer display thereby allowing the user to operate the computer in a manner similar to using a computer mouse simply by contacting the touch surface. Furthermore, the coordinate data fed back to the computer can be recorded in an application and redisplayed at a later time. Recording the coordinate data generated in response to user contacts is typically done when it is desired to record information written or drawn on the touch surface by the user. As the projector is separate from the touch surface of the touch screen, steps must be taken to calibrate the touch system thereby to align the projected image of the computer display with the coordinate system of the touch screen. During calibration, calibration marks are projected on to the touch surface and the user is prompted to contact the touch surface at the calibration mark locations resulting in coordinate data being generated. Since the coordinates of the calibration marks in the computer display coordinate system are known, the coordinate data generated by the touch screen in response to the user contacts at the calibration mark locations can be used to map the coordinate system of the touch screen to the computer display coordinate system. This calibration process corrects for projector/touch surface misalignment, and compensates for scale, skew, rotation and keystone distortion. Contacting the touch surface at least at three calibration mark locations is required to accurately correct for scale, skew and rotational misalignment of a projected image with a planar touch surface. Contacting the touch surface at least at four discrete calibration mark locations is required to accurately correct for keystone distortion. Keystone distortion is generally the result of non-orthogonal axial misalignment between the imaging device used to project the image and the touch surface. Contacting the touch surface at more than four calibration mark locations during the calibration process provides for more robust calibration of the touch system. It is common for interactive touch systems to have calibration processes requiring user input at up to eighty-one (81) calibration mark locations. Such a calibration process provides a high degree of accuracy but can be quite time consuming and laborious, since care must be taken to contact the touch surface at the exact location of each displayed calibration mark. If the imaging device or touch surface is bumped or moved, the entire calibration process may need to be repeated. As will be appreciated a calibration process for interactive touch systems that can be performed quickly and easily is desired. Therefore, it is an object of the present invention to provide a novel method and apparatus for calibrating an interactive touch system. SUMMARY OF THE INVENTION Accordingly, in one aspect of the present invention there is provided a method of calibrating an interactive touch system comprising: moving a pointer along at least one path on a touch surface over a calibration image presented on said touch surface; generating pointer coordinates generally continuously during pointer movement representing pointer contact locations on said touch surface; and mapping the coordinate system of the touch surface to the coordinate system of the calibration image using said pointer coordinates and said calibration image. The calibration image may include at least one demarcation providing visual guidance with respect to the at least one path along which the pointer is moved. In one embodiment, the demarcation is at least one line to be traced using the pointer. The at least one line may be straight or curved. In response to the mapping a calibrated touch surface coordinate system may be generated and stored in memory. Feedback may be provided during tracing indicating the degree of calibration of the touch surface coordinate system. The feedback may be a highlighted path provided in the calibration image representing the perceived path of the pointer in the calibration image coordinate system. According to another aspect of the present invention, there is provided a method of calibrating an interactive touch system comprising: displaying a calibration image on a touch surface, said calibration image specifying at least one path to be traced using a pointer; moving the pointer along the specified at least one tracing path; generating pointer coordinates generally continuously during said tracing representing pointer contact locations on said touch surface; mapping the coordinate system of the touch surface to the coordinate system of the calibration image using said pointer coordinates and said calibration image to calibrate the touch surface coordinate system; and providing feedback indicating the degree of calibration between the touch surface coordinate system and the calibration image coordinate system. According to yet another aspect of the present invention, there is provided a touch system comprising: a touch screen having a surface on which pointer contacts are made, said touch screen generating pointer coordinates in response to pointer contacts thereon; a computing device coupled to said touch screen and receiving pointer coordinates generated thereby; and a projection device coupled to said computing device, said projection device receiving display output from said computing device and projecting an image that is presented on said surface, wherein said computing device is operable to perform a calibration process, during said calibration process said computing device: providing display output to said projection device causing said projection device to project a calibration image on said surface, said calibration image being within the boundary of said surface and including at least one visual demarcation providing a guide with respect to at least one path to be traced across said surface; receiving the pointer coordinates during tracing along said at least one path; and processing the pointer coordinates using the calibration image to map the touch screen coordinate system to the display output coordinate system thereby to calibrate said touch system. The present invention provides advantages in that a reduced number of pointer contacts with the touch surface are required to calibrate the touch system. When visual feedback is provided, the user is able to see the results of the calibration in real-time allowing the user to terminate the calibration process whenever the degree of calibration is deemed to be acceptable. The effectiveness of the calibration process is enhanced by using attributes of the traced path such as slope, intersection points and start and end paths. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which: FIG. 1 is a schematic diagram of an interactive touch system in accordance with the present invention; FIG. 2 is an isometric view of a touch screen forming part of the interactive touch system of FIG. 1; FIG. 3 is an isometric view of a corner portion of the touch screen of FIG. 2; FIG. 4 is a schematic diagram of a camera assembly forming part of the touch screen of FIG. 2; FIG. 5 is a schematic diagram of a master controller forming part of the touch screen of FIG. 2; FIG. 6 shows one embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; FIG. 7 shows another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; FIG. 8 shows yet another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; FIG. 9 shows yet another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; FIG. 10 shows yet another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; FIG. 11 shows still yet another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; FIG. 12 shows still yet another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration; and FIG. 13 shows still yet another embodiment of a calibration image projected on to the touch surface of the touch screen during calibration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIG. 1, a camera-based interactive touch system such as that described in International PCT Application No. WO 02/03316 filed on Jul. 5, 2001, assigned to SMART Technologies Inc., assignee of the present invention, the content of which is incorporated herein by reference, is shown and is generally identified by reference numeral 50. As can be seen, interactive touch system 50 includes a touch screen 52 coupled to a digital signal processor (DSP) based master controller 54. Master controller 54 is also coupled to a computer 56. Computer 56 executes one or more application programs and provides display output that is presented on the touch screen 52 via a projector 58. The touch screen 52, master controller 54, computer 56 and projector 58 form a closed-loop so that user contacts on the touch screen 52 using an input device 68 (see FIG. 6) can be recorded as writing or drawing or used to control execution of application programs executed by the computer 56. The input device 68 may be any suitable device such as for example a user's hand or finger, a stylus, a marker, a pen, a pointer stick, a laser pointer, a retro-reflective pointer, a light pen, or other appropriate device (collectively referred to hereinafter as “pointer”). FIGS. 2 to 4 better illustrate the touch screen 52. Touch screen 52 includes a touch surface 60 bordered by a rectangular frame or bezel 62. Bezel 60 may be of the illuminated type such as that described in U.S. patent application Ser. No. 10/354,168 filed on Jan. 30, 2003 to Akitt et al., assigned to SMART Technologies Inc., assignee of the present invention, the content of which is incorporated herein by reference. Touch surface 60 is in the form of a rectangular, generally planar sheet of passive material. DSP-based CMOS digital cameras 630 to 633 are positioned adjacent each corner of the touch screen 52. Each digital camera 63N is mounted on a frame assembly 64 including an angled support plate 66 on which the digital camera 63N is mounted. Supporting frame elements 70 and 72 are mounted on the plate 66 by way of posts 74 and secure the plate 66 to the frame 62. Each digital camera 63N includes a two-dimensional CMOS image sensor 80 having an associated lens assembly, a first-in-first-out (FIFO) buffer 82 coupled to the image sensor 80 by a data bus and a digital signal processor (DSP) 84 coupled to the FIFO 82 by a data bus and to the image sensor 80 by a control bus. A boot EPROM 86 and a power supply subsystem 88 are also included. In the present embodiment, the CMOS camera image sensor 80 is of the type manufactured by National Semiconductor under Patent No. LM9617 and includes a 640×20 pixel subarray that can be operated to capture image frames at rates in excess of 200 frames per second. Arbitrary pixel rows of the image sensor 80 can be selected. Since the pixel rows can be arbitrarily selected, the pixel subarray can be exposed for a greater duration for a given digital camera frame rate providing for good operation in darker rooms in addition to well lit rooms. The FIFO buffer 82 is manufactured by Cypress under part number CY7C4211V and the DSP 84 is manufactured by Analog Devices under part number ADSP2185M. The DSP 84 receives image frames from the image sensor 80 and processes the image frames to determine the x-positions of a pointer within the image frames. In addition, the DSP 84 provides control information to the image sensor 80 via the control bus. The control information allows the DSP 84 to control parameters of the image sensor 80 such as exposure, gain, array configuration, reset and initialization. The DSP 84 also provides clock signals to the image sensor 80 to control the frame rate of the image sensor 80. The angle of the plate 66 and the optics of each digital camera 63N are selected so that the field of view (FOV) of each digital camera 63N is slightly beyond 90°. In this way, the entire touch surface 60 is within the field of view of each digital camera 63N with the field of view of each digital camera 63N extending slightly beyond a designated peripheral edge of the touch surface 60. Master controller 54 is best illustrated in FIG. 5 and includes a DSP 90, a boot EPROM 92, a serial line driver 94 and a power supply subsystem 95. The DSP 90 communicates with the DSPs 84 of the digital cameras 630 to 633 over a data bus via a serial port 96 and communicates with the computer 56 over a data bus via a serial port 98 and the serial line driver 94. In this embodiment, the DSP 90 is manufactured by Analog Devices under part number ADSP2185M. The serial line driver 94 is manufactured by Analog Devices under part number ADM222. The master controller 54 and each digital camera 63N follow a communication protocol that enables bidirectional communications via a common serial cable similar to a universal serial bus (USB). The transmission bandwidth is divided into thirty-two (32) 16-bit channels. Of the thirty-two channels, six (6) channels are assigned to each of the DSPs 84 in the digital cameras 630 to 633 and to the DSP 90 in the master controller 54 and the remaining two (2) channels are unused. The master controller 54 monitors the twenty-four (24) channels assigned to the DSPs 84. The DSPs 84 monitor the six (6) channels assigned to the DSP 90 of the master controller 54. Communications between the master controller 54 and the digital cameras 630 to 633 are performed as background processes in response to interrupts. During operation of the touch system 50, each digital camera 63N acquires image frames of the touch surface 60 within the field of view of its image sensor 80 at a desired frame rate and processes each acquired image frame to determine if a pointer is in the acquired image frame. During this operation, the DSP 84 reads each image frame from the FIFO buffer 82 and processes the image frame. If a pointer is in the acquired image frame, the image frame is further processed by the DSP 84 to determine the x-position of the pointer 68. The z-position of the pointer is also determined so that a determination can be made as to whether the pointer is contacting or hovering above the touch surface 60. Pointer information packets (PIPs) including the pointer position data, status and/or diagnostic information are then generated by the DSP 84 and the PIPs are queued for transmission to the master controller 54. The digital cameras 630 to 633 also receive and respond to command PIPs generated by the master controller 54. The master controller 54 polls the digital cameras 630 to 633 for PIPs in the queues. In this particular embodiment, the master controller 54 polls the digital cameras 63N at a rate exceeding the image sensor frame rates. Upon receipt of PIPs from the digital cameras 63N, the master controller 54 examines the PIPs to determine if the PIPs include pointer position data. If the PIPs include pointer position data, the master controller 54 triangulates the pointer position data in the PIPs to determine the position of the pointer relative to the touch surface 60 in Cartesian rectangular coordinates. The master controller 54 in turn transmits calculated pointer coordinates, status and/or diagnostic information to the computer 56. In this manner, the pointer coordinates transmitted to the computer 56 can be recorded as writing or drawing or can be used to control execution of application programs executed by the computer 56. The computer 56 also updates the display output conveyed to the projector 58 so that image presented on the touch surface 60 reflects the pointer activity. The master controller 54 also receives commands from the computer 56 and responds accordingly as well as generates and conveys command PIPs to the digital cameras 63N. Specifics of the manner in which the cameras 63N determine the pointer x and z positions from the image frame data and create PIPs is described in International PCT Application No. WO 02/03316 referenced previously and therefore, will not be described herein. During set up of the touch system 50, the projector 58 is positioned and aligned such that the computer display output that is projected on to the touch surface 60 by the projector 58 falls within the bezel 62. A calibration process is also performed to align the coordinate system of the touch screen 52 with the coordinate system of the image projected on to the touch surface 60, so that pointer coordinates generated by the touch screen 52 in response to a user contact on a point of the image projected on to the touch surface 60, correspond with the coordinates of the image point in the computer display coordinate system. The calibration process used to calibrate the touch system 50 will now be described with particular reference to FIG. 6. During calibration, the computer 54 generates a calibration image 100 which is projected on to the touch surface 60 by the projector 58. The calibration image 100 lies completely within the bezel 62. If the projector 58 and touch screen 52 are misaligned, the projected calibration image 100 may be scaled, skewed, rotated and/or suffer from keystone distortion and thus, as a result may appear trapezoidal on the touch surface 60. In FIG. 6, the calibration image 100 is rectangular but is illustrated as suffering from keystone distortion and thus, has a trapezoidal appearance. As a result, the rectangular calibration image 100 is shown as including a compressed top edge 102, a counter-clockwise rotated right edge 104, an elongated bottom edge 106, and a clockwise rotated left edge 108. The perimeter or border of the calibration image 100 defines a tracing path 112 that is used to calibrate the touch system 50 and map the coordinate system of the touch screen 52 to the computer display coordinate system. The calibration image 100 further includes text instructions 114 providing direction to the user to assist the user during the calibration process. Initially during calibration, first text instructions are presented on the touch surface 60 directing the user to contact the touch surface 60 with a pointer 68 at a location of their choosing along the perimeter of the calibration image 100. FIG. 6 shows the initial contact occurring at the top left corner of the calibration image 100. Once contact is detected with the touch surface 60, second text instructions are presented on the touch surface 60 directing the user to use the pointer 68 to trace a path along the perimeter of the calibration image 100, while maintaining continuous contact between the pointer 68 and the touch surface 60, until at least one full loop around the perimeter of the calibration image 100 has been completed. As will be appreciated, during pointer movement along the tracing path 112, the calibration image 100 does not change or require updating. As the user traces a path along the perimeter of the calibration image 100, the touch screen 52 generates pointer coordinate data corresponding to the locations where the pointer contacts are made. The computer 56 receives the pointer coordinate data and processes the pointer coordinate data to map the computer display coordinate system with the coordinate system of the touch screen 52. With the mapping complete, the calibrated touch screen coordinate system is stored by the computer 56 and is used by the computer 56 during normal operation of the touch system 50 to interpret pointer coordinates generated by the touch screen 52 in response to user contacts on the touch surface 60. In particular, the computer 56 processes the pointer coordinate data based on known properties of the tracing path 112. These properties may include the native geometry, aspect ratio, and resolution of the calibration image 100 or elements of the calibration image. The nature of the projector 58 may also affect the properties of the observed calibration image. A typical projector will produce a rectangular image on a plane normal to the axis of the lens (assuming that the projector is not configured to project at an angular offset). The geometry of the projected image will typically be either a 4:3 ratio, or a 16:9 ratio, with resolutions ranging from 640×480 to 1280×720. Of course, the calibration process can be used with different aspect ratios and with resolutions beyond the above noted range. Some assumptions assist in determining on which side (top, bottom, left, right) of the calibration image 100 the user is tracing. It can generally be assumed that a user will closely follow the tracing path 112 using the pointer 68 in an attempt to properly calibrate the touch system 50. The slope of the top or bottom edge 102, 106 of the calibration image 100 should be closer to horizontal than the slope of the left or right edge 104, 108. Likewise, the slope of the right or left edge 104, 108 of the calibration image 100 should be closer to vertical than that of the top or bottom edge 102, 106. One will recognize that a calibration image where this is not the case would be highly distorted and likely unusable. During the tracing process, the transition between pointer movement along two adjacent sides of the tracing path 112 is apparent from the pointer coordinate data generated by the touch screen 52 and reported to the computer 56. Examining the history of reported pointer coordinates clearly indicates the transition from one side of the tracing path to another. The transition between two adjacent sides of the tracing path 112 will be characterized by an inflection point, whereby the slope of contiguous pointer coordinates abruptly changes. In this example, the inflection points designate the corners of the calibration image 100 allowing the coordinate of the corners to be extracted. The sequence and relative order of each inflection point during the continuous tracing process can also assist in revealing to which corner it belongs. The computer 56 may use for example traditional perspective geometry techniques such as plane to plane homography to determine the correct mapping of the touch screen coordinate system to the coordinate system of the projected calibration image 100, or may employ more complex artificial intelligence techniques. After calibration, the location of contact between the pointer 68 and the touch surface 60 will correspond with mouse or script input at the same location within the observed calibration image 100. To enable a high degree of accuracy, the resolution of the touch screen coordinate system should be at least equal to the resolution of the observed calibration image 100. Increased resolution of the touch screen coordinate input system over that of the observed calibration image 100 can provide sub-pixel accuracy for user input. One will recognize that the above calibration process provides a greatly increased amount of pointer coordinate data as compared to prior art systems that require users to contact the touch surface at numerous discrete calibration mark locations. This is due to the fact that the continuos movement of the pointer 68 along the tracing path 112 is tracked. Each pointer coordinate output by the touch screen 52 during tracing may be used during calibration of the touch screen coordinate system with the coordinate system of the projected calibration image 100. The pointer coordinates output by the touch screen 52 provide even more data when taken in combination with attributes of the tracing path such as for example, slope information extracted from the pointer coordinates. For example, the slope of a side of the tracing path 112 in conjunction with pointer coordinates gathered over some or all of the length of the side, may provide a more accurate correlation between the traced path of the pointer 68 and the tracing path 112 in the calibration image 100. Although the inflection points may be used to designate corners of the calibration image 100, those of skill in the art will appreciate that using a calibration image having discrete corner coordinates is not absolutely necessary. Also, those of skill in the art will appreciate that there may be cases where the inflection points do not represent the true corners of the calibration image 100 (due to poor tracing for example). If desired, visual feedback may be provided to the user during the calibration process. In this case, when the user first contacts the touch surface 60 with the pointer 68 and the touch screen 52 outputs the pointer coordinates to the computer 56, a real-time visual cue 120, in this example highlighting, is injected into the calibration image reflecting the perceived location of the pointer contact with the calibration image 100. As the user proceeds to move the pointer 68 along the tracing path 112 and more pointer coordinates are generated, the computer 56 learns more about the geometry of the calibration image 100 and hence, is able to generate a more accurate mapping between the touch screen and computer display coordinate systems. As the user continues moving the pointer 68 along the tracing path 112, the location of the visual cue 120 is updated throughout the calibration process based on the corrections made to the calibrated touch screen coordinate system. Thus, as the user progresses to move the pointer along the tracing path 112 and the calibrated touch screen coordinate system is refined, the degree of alignment between the visual cue 120 and the calibration image 100 improves. As calibration pointer coordinate data is being generally continuously generated as the user moves the pointer 68 along the tracing path 112, an acceptable degree of calibration may be achieved before a complete loop around the calibration image 100 is made. In this instance, by using real-time visual feedback provided to the user, the calibration process may be terminated at any time the user determines that an acceptable degree of calibration has been achieved. There may also be cases where the degree of calibration is not acceptable after one complete tracing along the perimeter of the calibration image 100. With real-time visual feedback, the user can acknowledge that further calibration is required, and can continue tracing along the perimeter of the calibration image 100 uninterrupted until a sufficient degree of calibration is achieved. As will be appreciated by those of skill in the art, an improved calibration process is achieved which requires the user to make only one contact with the touch surface using a pointer and move the pointer continuously along a guided tracing path. FIG. 7 shows an alternate calibration image 150 for display during the calibration process. In this example, the rectangular calibration image similarly suffers from keystone distortion and thus, appears trapezoidal. In addition to its perimeter the calibration image 150 includes a pair of vertically spaced, horizontal lines 160 and 162. Line 160 extends horizontally near the top edge 152 of the calibration image 150. Line 162 extends horizontally near the bottom edge 156 of calibration image 150. The geometry of the lines 160, 162 on the touch surface 60 will depend on the alignment of the touch screen 52 with the normal axis of the projector 58. Text instructions 166 direct the user to trace a path along each of the projected lines 160,162. The user may be directed as to which line should be traced first, or from which side to begin. However, from the previous discussion, one of skill in the art will recognize that these directions are not absolutely necessary. As described above, during tracing along the lines 160, 162, pointer coordinates are continuously reported by the touch screen 52 to the computer 56. As a result of tracing each line, sufficient pointer coordintate data becomes available to extract the geometry of the lines 160, 162 with respect to the touch screen coordinate system. Each line also provides slope information, as well as discrete beginning and end points. The beginning and end points of each line may be processed to create discrete points or connected to create virtual vertical lines. Depending on the geometry of the calibration image 150, the discrete locations of the end points may not be required to accurately map the touch screen coordinate system to the coordinate system of the calibration image 150. As with the previous embodiment, visual feedback may be provided to the user as the user traces along the lines 160, 162 to indicate visually the perceived position of the pointer 68 relative to the calibration image 150. Utilizing the visual feedback, the user continues to trace each line 160, 162, alternately and/or repeatedly, until a sufficient degree of calibration is achieved. Similar to the previous embodiment, the visual feedback is a visual cue 164, again highlighting, injected into the calibration image 150 that tracks movement to the pointer 68 along the touch surface 60. When tracing a path or paths defined by the calibration image during the calibration process, there may be some ambiguity as to where exactly a user is to make contact with the touch surface 60. Users may trace inside of, outside of, or on directly overlapping elements of the tracing path or paths. By utilizing sufficiently complex tracing paths and/or visual cues, these ambiguities can be resolved and better calibration achieved. FIG. 8 shows yet another embodiment of a calibration image 200 for display during the calibration process. In this example, the rectangular calibration image 200 suffers from keystone distortion and thus, appears trapezoidal. In addition to its perimeter, the calibration image 200 includes concentric outer and inner loops 210 and 212 respectively. The outer and inner loops are rectangular but appear as trapezoids in the distorted calibration image 200. The space between the outer and inner loops 210 and 212 defines a tracing path 214. Text instructions 216 direct the user to move the pointer 68 along the tracing path 214. In this case, the confined nature of the tracing path 214 and the text instructions provide unambiguous direction (both visually and textually) as to where pointer contact and movement should be made. FIG. 9 shows yet another embodiment of a calibration image 250 for display during the calibration process. In this example, the calibration image does not suffer from noticeable keystone distortion and thus, appears rectangular. The calibration image 250 is designed to provide a level of amusement to what some may consider a mundane task. A maze 260 is included in the calibration image 250 having known properties. As illustrated, there is only a single correct tracing path 266 that navigates through the maze from its start 262 to its finish 264. The maze 260 presents a defined start and finish point, and thus at least two discrete pointer coordinate locations. Tracing a path through the maze 260 also generates pointer coordinates corresponding to a very complex shape. Back and forth motions, as a result of pointer movement down a wrong path within the maze 260, provide distinct information regarding the pointer location within the maze. The directional and displacement components of the traced path can be extracted and compared to a master image, providing a substantial number of identifiable pointer coordinates that can to be mapped against the known properties of the maze. A more complex maze will provide more pointer coordinates for calibrating the touch screen and computer display coordinate systems. If desired, the maze 260 may include more than one solution allowing for a user to trace different paths that navigate through the maze from start to finish. In this case, some tracing paths will provide more calibration information and some tracing paths will provide less calibration information. Calibration may be based on slope, displacement, direction, midpoint of lines, contiguous coordinates, inflection points, etc. As with the previously described examples, paths through the maze can be traced several times to improve calibration accuracy. Alternate mazes having different tracing paths may also be presented once one maze has been completed to provide increased robustness. FIG. 10 shows still yet another embodiment of a calibration image 300 for display during the calibration process. In this example, the calibration image 300 does not suffer from noticeable keystone distortion and thus, appears rectangular. The calibration image 300 includes a centrally disposed continuous overlapping loop in the form of an “infinity sign” or “figure-eight” 310. The user is directed to trace a path 312 along the loop 310. The beginning and end locations may be predetermined or chosen at the user's discretion. As with certain previous embodiments, the user is only required to contact the touch surface 60 with the pointer 68 once during the calibration process. A continuous stroke is used to trace a path along the loop 310. Visual feedback such as a visual cue 320, in this case highlighting allows the user to continue tracing along the loop 310 until a sufficient degree of calibration is achieved. Pointer coordinates reported by the touch screen 52 to the computer 56 are compared to predefined properties of the loop 310 in the calibration image 300. Pointer coordinates corresponding to the extreme top, bottom, left, and right portions of the loop 310 may be of use. The continuously changing slopes in the loop 310 are of particular use in calibration. The loop 310 also includes a discrete location 311 where the loop line crosses over itself. FIG. 11 shows still yet another embodiment of a calibration image 350 for display during the calibration process. In this example, the calibration image 350 does not suffer from noticeable keystone distortion and thus, appears rectangular. The calibration image 350 again utilizes two lines 360, 362. In this case the lines 360, 362 run diagonally from top left to bottom right, and top right to bottom left. The lines 360, 362 are illustrated crossing generally at the center point 364 of the calibration image 350. Tracing paths along the lines 360 and 362 require at least two discrete strokes or overlapping strokes. A user may chose to trace for instance, two straight lines crossing at the center point 364, two “v” figures meeting at the center point 364, or one continuous overlapping stroke. In each case, discrete start, end, and central points in addition to slope information can be extracted from the pointer coordinates reported by the touch surface 52 to the computer 56. FIG. 12 shows still yet another embodiment of a calibration image 400 for display during the calibration process. In this example, the calibration image 400 does not suffer from noticeable keystone distortion and thus, appears rectangular. The calibration image 400 includes a somewhat abstract line 410. The line 410 comprises three loops extending from left to right, defining three intersection points where the line 410 crosses itself. Pointer coordinates corresponding to the start and end points of the line 410 are easily extracted. The locations where the line 410 crosses itself also provides discrete pointer coordinates. The slope of the curves within the line 410 provide further information useful in mapping the touch screen coordinate system to the coordinate system of the calibration image 400. FIG. 13 shows still yet another embodiment of a calibration image 450 for display during the calibration process. The calibration image 450 is similar to that shown in FIG. 8 and suffers from keystone distortion. As a result, the calibration image 450 appears trapezoidal. Calibration image 450 includes concentric outer and inner loops 470 and 460 respectively. In this example, the outer and inner loops are rectangular but appear as trapezoids in the distorted calibration image 450. Text instructions 480 direct the user to trace paths following each loop rather than in the space between them. By providing two geometric shapes, during the calibration process an increased number of pointer coordinates for mapping the touch screen coordinate system with the coordinate system of the calibration image 450 are provided. Various geometric shapes and patterns may be included in the calibration image to be traced by a user. Geometric shapes including squares, rectangles, trapezoids, rhombuses, circles, ovals, ellipses, and triangles provide distinctive properties from which calibration can be achieved. Various combinations of such shapes may be presented in a single calibration image. The above-described embodiments illustrate a calibration process for interactive touch systems whereby a user traces a path presented in a calibration image using a continuous stroke. It should be understood that each path presented in the calibration image need not be traced by a single continuous stroke to enjoy the benefit of the present invention. For example, a user may trace a rectangular path using four discrete continuous strokes, one along each side of the rectangle. Each of these strokes would comprise discrete beginning and end pointer coordinates, as well as incremental pointer coordinates along the length of the strokes. With pointer coordinate data associated with the four sides of the rectangle, there is a substantial amount of pointer coordinate data available for mapping the touch screen coordinate system to the coordinate system of the projected image. Thus, a user need only trace a portion of the path presented in the calibration image with a continuous stroke in order for calibration to be effective. The present calibration process provides advantages in that it can be utilized to calibrate an image projected on to a non-planar touch surface. The surface may be curved, hemispherical, somewhat irregular, etc. The process of using continuous pointer coordinates generated in response to pointer strokes on the touch surface, as opposed to using discrete pointer coordinates generated in response to discrete pointer contacts at predefined locations, makes calibration of an irregular touch surface possible. As will be appreciated, using prior art techniques would take a substantial number of discrete pointer contacts to accurately map a hemispherical surface. Acquiring pointer coordinates only at discrete contact locations would also likely require some foreknowledge of the geometry of the touch surface with the number of discrete pointer contacts required increasing with increased irregularity of the touch surface. Utilizing the present invention and a calibration image such as that illustrated in FIG. 9, a significant number of pointer coordinates are gathered over a substantial area of the touch surface. These pointer coordinates can be processed individually and in relation to one another to effectively define the properties of the touch surface. The number of pointer coordinates used for calibration need not be fixed nor predetermined prior to engaging the calibration process. A non-linear process may be implemented to extract the appropriate number of pointer coordinates based on the irregularity of the touch surface. In yet another embodiment, a user may calibrate the touch screen coordinate system without the use of a predetermined path within the calibration image. In this embodiment, the user contacts the touch surface thereby causing the touch screen 52 to generate pointer coordinates. A visual cue, such as an arrow, is generated by the computer 56 and projected on to the touch surface 60 within the calibration image at the apparent pointer contact location within the calibration image. In an uncalibrated touch system, the location of the visual cue will not likely correspond with the pointer contact location. The user while maintaining contact with the touch surface moves the pointer towards the displayed arrow. The pointer coordinates generated during the pointer movement are reported by the touch screen 52 to the computer 56. The computer 56 in turn processes the pointer coordinates and mathematically determines where the pointer is with respect to location of the visual cue in the calibration image. By having the user continuously trace a path consistent with the observed location of the visual cue, the computer will eventually calibrate the touch system so that the touch screen coordinate system and computer coordinate system are mapped. Although the tracing paths shown in FIGS. 6, 7 and 10 to 13 are represented in the calibration images by solid continuous lines, those of skill in the art will appreciate that the tracing paths may be represented by dashed or dotted lines or by other demarcations that provide visual guidance to the user for the paths to be traced. Although embodiments of the present invention have been described, those of skill in the art will appreciate that the variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.
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<SOH> BACKGROUND OF THE INVENTION <EOH>Interactive touch systems are well known in the art and typically include a touch screen having a touch surface on which contacts are made using a pointer in order to generate user input. Pointer contacts with the touch surface are detected and are used to generate corresponding output based on the locations of contact. There are basically two general types of touch systems available and they can be broadly classified as “active” touch systems and “passive” touch systems. Interactive touch systems have a number of applications relating to computer operation and video display. For example, U.S. Pat. No. 5,448,263 to Martin, assigned to SMART Technologies Inc., assignee of the present invention, discloses a passive touch system including a touch screen coupled to a computer. The computer display is projected on to the touch surface of the touch screen via an imaging device such as a projector. The coordinates representing specific locations on the touch surface are mapped to the coordinate system of the computer display. When a user contacts the touch surface of the touch screen, coordinate data is generated by the touch screen and fed to the computer. The computer maps the received coordinate data to the computer display thereby allowing the user to operate the computer in a manner similar to using a computer mouse simply by contacting the touch surface. Furthermore, the coordinate data fed back to the computer can be recorded in an application and redisplayed at a later time. Recording the coordinate data generated in response to user contacts is typically done when it is desired to record information written or drawn on the touch surface by the user. As the projector is separate from the touch surface of the touch screen, steps must be taken to calibrate the touch system thereby to align the projected image of the computer display with the coordinate system of the touch screen. During calibration, calibration marks are projected on to the touch surface and the user is prompted to contact the touch surface at the calibration mark locations resulting in coordinate data being generated. Since the coordinates of the calibration marks in the computer display coordinate system are known, the coordinate data generated by the touch screen in response to the user contacts at the calibration mark locations can be used to map the coordinate system of the touch screen to the computer display coordinate system. This calibration process corrects for projector/touch surface misalignment, and compensates for scale, skew, rotation and keystone distortion. Contacting the touch surface at least at three calibration mark locations is required to accurately correct for scale, skew and rotational misalignment of a projected image with a planar touch surface. Contacting the touch surface at least at four discrete calibration mark locations is required to accurately correct for keystone distortion. Keystone distortion is generally the result of non-orthogonal axial misalignment between the imaging device used to project the image and the touch surface. Contacting the touch surface at more than four calibration mark locations during the calibration process provides for more robust calibration of the touch system. It is common for interactive touch systems to have calibration processes requiring user input at up to eighty-one (81) calibration mark locations. Such a calibration process provides a high degree of accuracy but can be quite time consuming and laborious, since care must be taken to contact the touch surface at the exact location of each displayed calibration mark. If the imaging device or touch surface is bumped or moved, the entire calibration process may need to be repeated. As will be appreciated a calibration process for interactive touch systems that can be performed quickly and easily is desired. Therefore, it is an object of the present invention to provide a novel method and apparatus for calibrating an interactive touch system.
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<SOH> SUMMARY OF THE INVENTION <EOH>Accordingly, in one aspect of the present invention there is provided a method of calibrating an interactive touch system comprising: moving a pointer along at least one path on a touch surface over a calibration image presented on said touch surface; generating pointer coordinates generally continuously during pointer movement representing pointer contact locations on said touch surface; and mapping the coordinate system of the touch surface to the coordinate system of the calibration image using said pointer coordinates and said calibration image. The calibration image may include at least one demarcation providing visual guidance with respect to the at least one path along which the pointer is moved. In one embodiment, the demarcation is at least one line to be traced using the pointer. The at least one line may be straight or curved. In response to the mapping a calibrated touch surface coordinate system may be generated and stored in memory. Feedback may be provided during tracing indicating the degree of calibration of the touch surface coordinate system. The feedback may be a highlighted path provided in the calibration image representing the perceived path of the pointer in the calibration image coordinate system. According to another aspect of the present invention, there is provided a method of calibrating an interactive touch system comprising: displaying a calibration image on a touch surface, said calibration image specifying at least one path to be traced using a pointer; moving the pointer along the specified at least one tracing path; generating pointer coordinates generally continuously during said tracing representing pointer contact locations on said touch surface; mapping the coordinate system of the touch surface to the coordinate system of the calibration image using said pointer coordinates and said calibration image to calibrate the touch surface coordinate system; and providing feedback indicating the degree of calibration between the touch surface coordinate system and the calibration image coordinate system. According to yet another aspect of the present invention, there is provided a touch system comprising: a touch screen having a surface on which pointer contacts are made, said touch screen generating pointer coordinates in response to pointer contacts thereon; a computing device coupled to said touch screen and receiving pointer coordinates generated thereby; and a projection device coupled to said computing device, said projection device receiving display output from said computing device and projecting an image that is presented on said surface, wherein said computing device is operable to perform a calibration process, during said calibration process said computing device: providing display output to said projection device causing said projection device to project a calibration image on said surface, said calibration image being within the boundary of said surface and including at least one visual demarcation providing a guide with respect to at least one path to be traced across said surface; receiving the pointer coordinates during tracing along said at least one path; and processing the pointer coordinates using the calibration image to map the touch screen coordinate system to the display output coordinate system thereby to calibrate said touch system. The present invention provides advantages in that a reduced number of pointer contacts with the touch surface are required to calibrate the touch system. When visual feedback is provided, the user is able to see the results of the calibration in real-time allowing the user to terminate the calibration process whenever the degree of calibration is deemed to be acceptable. The effectiveness of the calibration process is enhanced by using attributes of the traced path such as slope, intersection points and start and end paths.
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20040707
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20080513
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20060112
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64815.0
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G09G500
| 0
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LEE JR, KENNETH B
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METHOD AND APPARATUS FOR CALIBRATING AN INTERACTIVE TOUCH SYSTEM
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UNDISCOUNTED
| 0
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ACCEPTED
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G09G
| 2,004
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10,885,245
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ACCEPTED
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Counter-top scanner with bump protection mechanism and scan angle adjustment mechanism
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An improved counter-top bar code scanner is equipped with a bump protection mechanism and a scan angle adjustment mechanism. The bump protection mechanism is provided in the form of a protective sheath fabricated of a shock-absorbing material. The scan angle adjustment mechanism is provided in the form of a movable bracket adjustably mounted to the scanner housing. If the bracket is mounted to a fixed surface, the bracket remains fixed but permits adjustments of the housing to any of the plurality of positions relative to the fixed surface.
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1. A bar code scanner, comprising: (a) a housing including: (i) a substantially omnidirectional laser scanning platform mounted therein, (ii) a window for admitting laser energy into the housing and for allowing laser energy to pass out of the housing; and (iii) a shock-absorbing mechanism in the form of a protective sheath that functions to protect against damage if the bar code scanner is dropped and/or subjected to mechanical shock; and (b) a movable bracket adjustably mounted to the housing such that, if the movable bracket is mounted to a fixed surface, the movable bracket remains fixed, but permits adjustment of housing to any of a plurality of positions relative to the fixed surface. 2. The bar code scanner of claim 1 wherein the protective sheath is fabricated of rubber and/or flexible plastic. 3. The bar code scanner of claim 2 wherein the protective sheath is fabricated so as to permit removal of the sheath from the housing. 4. The bar code scanner of claim 1 wherein the protective sheath includes an opening such that, when the protective sheath is installed on the housing, the opening substantially coincides with the window. 5. The bar code scanner of claim 2 wherein the protective sheath is a substantially permanent part of the housing. 6. The bar code scanner of claim 2 wherein the housing defines an approximate cubic volume having an upper surface with four upper corners and a lower surface with four lower corners. 7. The bar code scanner of claim 6 wherein the protective sheath protects the four upper corners and four lower corners of the bar code scanner. 8. The bar code scanner of claim 2 wherein the housing is provided with top-mounted, front-mounted, or side-mounted LED power and/or LED “good bar code read” indicators. 9. The bar code scanner of claim 2 wherein the housing is molded of hard plastic. 10. The bar code scanner of claim 9 wherein the housing is formed in two half-sections with tongue-and-groove edges to provide an interlocking fit. 11. The bar code scanner of claim 2 wherein the window is generally square and/or rectangular in configuration and mounted in an aperture of the housing. 12. The bar code scanner of claim 11 wherein the window is seated in, and/or held by, one or more grooves or projections formed in the housing. 13. The bar code scanner of claim 12 wherein the window is fabricated of a square and/or rectangular section of transparent acrylic-type plastic with optical filtering properties. 14. The bar code scanner of claim 1 wherein the movable bracket includes a position adjustment mechanism providing position adjustment of the housing relative to the bracket about a rotational axis a-a′. 15. The bar code scanner of claim 14 wherein the position adjustment mechanism is provided in the form of an annular flange having an inner diameter and an outer diameter. 16. The bar code scanner of claim 15 wherein, along an interior (inner) surface of the annular flange proximate to the housing, between the inner and outer diameters, are provided one or more projections, notches, ridges, grooves, nubs, fingers, detents, and/or bosses that engage one or more corresponding mating structures on the housing. 17. The bar code scanner of claim 16 wherein the one or more projections, notches, ridges, grooves, nubs, fingers, detents, and/or bosses are provided in the form of a plurality of rounded teeth that engage one or more corresponding rounded grooves of the housing. 18. The bar code scanner of claim 14 wherein the movable bracket includes two or more mounting holes for mounting to a surface such as a countertop and/or point of sale terminal. 19. The bar code scanner of claim 14 wherein the protective sheath is provided in the form of a removable and reinstallable encasement fabricated of a rubberized shock-absorbing material. 20. The bar code scanner of claim 3 wherein the protective sheath includes one or more projections and mating notches, each notch mating with a corresponding projection, so as to facilitate quick and easy removal and/or installation of the protective sheath on the housing. 21. The bar code scanner of claim 3 wherein the protective sheath is removable from, and reinstallable on, the housing, without the use of any projections or notches, by a mechanical flexure of the protective sheath. 22. The bar code scanner of claim 1 adapted to perform scanning operations from a hand-held position, a free-standing position, and a fix-mounted position; wherein the hand-held and free-standing positions are achieved by permitting the removable bracket to rest upon a surface but wherein the bracket is not attached to the surface; and wherein the fix-mounted position is achieved by mounting the bracket to the surface. 23. The bar code scanner of claim 1 adapted to perform scanning operations from a hand-held position, a free-standing position, and a fix-mounted position; wherein the removable bracket is attached to the surface and at least one of the hand-held position and the free-standing position is achieved by removing the housing from the removable bracket. 24. The bar code scanner of claim 1 wherein the scanning platform includes an object detection circuit for detecting and determining the presence of an object within an operative scanning range. 25. The bar code scanner of claim 22, wherein the housing and the scanning platform provide a substantially omnidirectional scan from a free-standing fixed position atop a counter or while handheld by a user. 26. The bar code scanner of claim 23, wherein the housing and the scanning platform provide a substantially omnidirectional scan from a free-standing position fixed atop a counter or while handheld by a user. 27. The bar code scanner of claim 1 wherein the removable bracket has a flat bottom configured for placement directly on a counter-top surface. 28. The bar code scanner of claim 1 wherein the housing has a substantially flat bottom configured for placement directly on a counter-top surface. 29. The bar code scanner of claim 1 wherein the movable bracket is detachable from the housing. 30. A bar code scanner comprising: a scanner housing having an approximately cubical volume and comprising: (a) a light transmission aperture; (b) an adjustable mounting bracket removably attached to the scanner housing; wherein the housing is equipped with a shock-absorbing mechanism in the form of a protective sheath that functions to protect against damage if the bar code scanner is dropped and/or subjected to mechanical shock; (c) an omnidirectional laser scanning engine mounted within the housing and including: (i) a laser beam producing mechanism for producing a laser beam, (ii) a laser beam sweeping mechanism having at least first, second and third light reflective surfaces each being disposed at a different acute angle with respect to a rotational axis of the laser beam sweeping mechanism for sequentially sweeping the laser beam about the rotational axis along a plurality of different paths, (iii) a stationary array of at least first second, third and fourth light reflective surfaces; (iv) a laser light collection subsystem, including a light collection element for collecting return laser light, the light collection subsystem further including a light receiving mechanism for detecting the collected return laser light and producing an electrical signal indicative of the detected laser light, (v) a signal processing mechanism for processing the electrical signal and producing scan data representative of a scanned code symbol, and (vi) a control mechanism for controlling the operation of the omnidirectional laser scanning engine. 31. The bar code scanner of claim 30, wherein a beam directing element is mounted to the light collection element for folding the laser beam in the housing. 32. The bar code scanner of claim 30 further comprising: an object detection mechanism mounted in the housing for detecting an object located in an object detection field defined external to the housing and for generating a first activation signal for transmission to the control mechanism, whereby the laser beam producing mechanism, the laser beam sweeping mechanism, the light receiving mechanism and the signal processing mechanism are automatically activated upon the detection of the object. 33. A laser scanner comprising: (a) a hand-supportable housing having a light transmission window through which laser light can exit the hand-supportable housing, travel towards an object bearing a code symbol and reflect therefrom, and at least a portion of the reflected laser light travel back through the light transmission window and enter the hand-supportable housing; wherein the housing is equipped with a shock-absorbing mechanism in the form of a protective sheath that functions to protect against damage if the laser scanner is dropped and/or subjected to mechanical shock; the hand-supportable housing having a longitudinal extent which extends along a central reference axis; (b) a movable bracket adjustably mounted to the housing such that, if the movable bracket is mounted to a fixed surface, the movable bracket remains fixed, but permits adjustment of housing to any of a plurality of positions relative to the fixed surface; (c) a laser beam producing mechanism disposed within the hand-supportable housing for producing a laser beam; (d) a laser beam sweeping mechanism mounted within the hand-supportable housing for rotation about a rotational axis intersecting the central reference axis, where the intersection of the rotational axis and the central reference axis defines a central reference plane which extends along the longitudinal extent of the hand-supportable housing; the laser beam sweeping mechanism having a plurality of rotating light reflective surfaces each being disposed at a different acute angle with respect to the rotational axis, for sequentially sweeping the laser beam about the rotational axis along a plurality of different paths; (e) a stationary array comprised of a plurality of stationary light reflective surfaces mounted within the hand-supportable housing with respect to the central reference axis and disposed substantially under the light transmission window; wherein at least two of the plurality of the stationary light reflective surfaces are symmetrically disposed on opposite sides of the central reference plane, and closely adjacent the laser beam sweeping mechanism; (f) a light collection subsystem disposed within the hand-supportable housing, and including (1) a light collection element, mounted along the central reference plane and adjacent at least two of the stationary light reflective surfaces, for allowing the laser beam produced from the laser beam producing mechanism to pass along a portion of the central reference plane, to the laser beam sweeping mechanism, for sweeping about the rotational axis thereof along the plurality of different paths, and (2) a light receiver for receiving light from the light collection element at a point substantially within the central reference plane, and detecting the received light and producing an electrical signal indicative of the detected light; (g) a signal processor disposed within the hand-supportable housing, for processing the electrical signal and producing scan data representative of a scanned code symbol; (h) a control mechanism within the hand-supportable housing for controlling the operation of the hand-supportable laser scanner so that, during scanner operation, the laser beam produced from the laser beam producing mechanism passes along a portion of the central reference plane, to at least one of the rotating light reflective surfaces of the laser beam sweeping mechanism, and as the laser beam sequentially reflects off a plurality of the rotating light reflective surfaces, the laser beam is repeatedly swept across a plurality of the stationary light reflective surfaces, thereby producing a plurality of groups of plural scan lines, respectively, which are projected out through the light transmission window and intersect about a projection axis within an approximately collimated, frustral, and/or pyramidal scanning volume having an approximately columnar extent and extending from adjacent the light transmission window to at least about six inches therefrom so as to produce a collimated projected scanning pattern; and (i) the hand-supportable housing being supportable relative to an object bearing a code symbol so that when a code symbol is presented within the collimated scanning volume, the code symbol is scanned omnidirectionally by the collimated scanning pattern, (ii) at least a portion of the laser light reflected from the scanned code symbol is directed through the light transmission window, reflected off at least one of the stationary light reflective surfaces, and then reflected off at least one of the rotating light reflective surfaces of the laser beam sweeping mechanism, and (iii) thereafter the reflected laser light is collected by the light collection element, and received by the light receiver for detection, whereupon the electrical signal is produced for processing by the signal processor; wherein the hand-supportable housing allows the user to control the direction of the projection axis by adjusting the movable bracket relative to the housing and observing the window of the housing, to thus align the collimated scanning volume with the bar code symbol on the object to be scanned and identified. 34. The laser scanner of claim 33, wherein the signal processor further comprises a data processor for decoding the scan data and producing data representative of the scanned code symbol. 35. The laser scanner of claim 33, wherein the different acute angles are selected so that the scan lines in each group of scan lines are substantially equidistant from each other throughout at least a range of distances from the light transmission window. 36. The laser scanner of claim 33, wherein the laser beam producing mechanism comprises a laser diode mounted with respect to the central reference axis. 37. The laser scanner of claim 33, wherein the first, second, third, and fourth stationary light reflective surfaces comprise first, second, third, and fourth mirrors, respectively. 38. The laser scanner of claim 33, wherein the collimated scanning pattern is oriented along the longitudinal extent of the hand-supportable housing and exits the window in a direction substantially normal to the window so as to facilitate scanning of code symbols presented to the collimated scanning volume. 39. The laser scanner of claim 33 wherein the movable stand is positionable upon a counter surface, and includes a position adjustment mechanism for supporting the hand-supportable housing in any one of a plurality of positions above the counter surface so that the collimated scanning pattern is projected about the projection axis above the counter surface in any one of a plurality of orientations corresponding to the plurality of positions. 40. The laser scanner of claim 33, wherein the light receiver comprises a photodetector. 41. The laser scanner of claim 40, wherein the photodetector is located on a circuit board, at a height above the laser beam sweeping mechanism, and substantially within the central reference plane. 42. The laser scanner of claim 33, wherein the code symbol is a bar code symbol. 43. The laser scanner of claim 33, wherein the light collecting element is a light collecting mirror having a focal distance, substantially at which the light receiver is located. 44. The laser scanner of claim 33, wherein each scan line in a first group of scan lines is substantially parallel to each other scan line in the first group of scan lines, and each scan line in a second group of scan lines is substantially parallel to each other scan line in the second group of scan lines. 45. An automatic projection laser scanning system comprising: a hand-supportable housing having a light transmission aperture through which visible light can exit and enter into the hand-supportable housing; wherein the housing is equipped with a shock-absorbing mechanism in the form of a protective sheath that functions to protect against damage if the bar code scanner is dropped and/or subjected to mechanical shock; a movable bracket adjustably mounted to the housing such that, if the movable bracket is mounted to a fixed surface, the movable bracket remains fixed, but permits adjustment of housing to any of a plurality of positions relative to the fixed surface; an object detector in the hand-supportable housing, for detecting an object located in a scanning volume extending externally from the hand supportable housing, and automatically generating an activation signal in response to the detection of the object located therein; an activatable scan data reading mechanism in the hand-supportable housing, for reading scan data from a detected object located in the scanning volume, the scan data reading mechanism including: a laser beam generator for generating a visible laser beam and directing the visible laser beam through the light transmission aperture and into the scanning volume, a laser beam scanner for repeatedly scanning the visible laser beam so as to produce a highly collimated scanning pattern of approximately columnar extent within the scanning volume, for scanning a code symbol on the detected object presented therein, a laser light detector for detecting the intensity of laser light reflected off the bar code symbol and passing through the light transmission aperture as the visible laser beam is repeatedly scanned within the scanning volume, and a receiver for automatically producing scan data indicative of the detected intensity; an activatable scan data processor for processing produced scan data so as to detect and decode the bar code symbol on the detected object, and automatically producing symbol character data representative of the decoded bar code symbol; and a control mechanism for controlling the operation of the automatic bar code symbol reading system; wherein the movable bracket allows the user to control the direction of the projection axis by adjusting the position of the hand-supportable housing relative to the bracket, and thus align the approximately columnar scanning volume with the bar code symbol on the object to be scanned and identified. 46. The automatic projection laser scanning system of claim 45, wherein the laser beam generator comprises a laser diode. 47. The automatic projection laser scanning system of claim 45, wherein the bar code symbol has first and second envelope borders, and wherein the scan data processor comprises a detector adapted to detect the first and second envelope borders of the bar code symbol, and a mechanism for decoding the detected bar code symbol. 48. The automatic projection laser scanning system of claim 45, wherein the object detector comprises a receiver for receiving energy reflected from an object within an object detection field defined external to the housing and having an essentially volumetric extent, and wherein the collimated scanning pattern is characterized by at least one scanning plane having an essentially planar extent, and wherein the object detection field spatially encompasses at least a portion of the collimated scanning pattern. 49. The automatic projection laser scanning system of claim 45, wherein the laser beam generator is operated in a pulsed laser mode so as to generate a pulsed visible laser beam, which is directed through the light transmission aperture and repeatedly scanned across the collimated scanning pattern and the bar code symbol on the detected object. 50. The automatic projection laser scanning system of claim 49, wherein the object detector includes a transmitter for transmitting a pulse signal through a first optical element and into the scanning volume, a signal receiver for receiving the transmitted pulse signal reflected off the object in the scanning volume, and a signal comparator for comparing the received pulse signal with the transmitted pulse signal and automatically generating an activation signal indicative of the presence of the object in the scanning volume. 51. The automatic projection laser scanning system of claim 50, wherein the transmitter comprises an infra-red light source in the hand-supportable housing for producing an infra-red light pulse which is transmitted through the first optical element into the scanning volume, and wherein the receiver comprises an infra-red light detector and a second optical element for focusing reflected infra-red light pulses onto the infra-red light detector.
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RELATED CASES This is a continuation of U.S. patent application Ser. No. 10/043,900, filed Jan. 11, 2002, which is hereby incorporated by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to laser scanning systems, and more particularly to countertop bar code scanners that are equipped with adjustable mounting mechanisms and adapted to operate in an automatic “hands-free” mode of operation. 2. Description of Background Art Optical scanners of various types have been developed for scanning and decoding bar code symbols. These scanners adapt readily to some operational environments, but present shortcomings when used in other situations. For example, consider system applications involving point-of-sale (POS) terminals in retail stores and supermarkets, inventory and document tracking, and diverse data control applications. Retail point-of-sale counters are prime sales areas Display designs and product offerings may change on a regular basis. Inventory and document tracking involves scanning a number of items or documents of widely varying shapes and sizes. Diverse data control applications may involve managing data flow on a factory assembly line where a variety of components and processes must be tracked. These applications demand a bar code scanner that presents some degree of mechanical flexibility for use in any of a wide range of operational environments. Many existing bar code scanner designs are inadequately equipped to deal with the mechanical strains and stresses of day-to-day use. In many point-of-sale and factory environments, scanners are dropped, banged, and bumped. Delicate optical components may be damaged or misaligned, causing the performance of the scanner to degrade over time. Unfortunately, virtually all existing scanners are fabricated of high-impact polystyrene plastic, which provides only limited protection against mechanical shocks and bumps. In addition to lacking mechanical ruggedness, bar code scanners suffer from other deficiencies. Existing canners generally fall into one of two general categories: hand-held or stationary. The first category includes manually-actuated trigger-operated scanners, as well as automatically actuated hand-held scanners which do not utilize a triggering mechanism. The user positions the hand-held laser scanner at a specified distance from the object bearing the bar code. In the case of an automatically actuated scanner, the presence of the object is automatically detected, the presence of a bar code symbol on the object is detected, and thereafter the bar code symbol is automatically read. In the case of trigger-operated scanners, the user positions the scanner at a specified distance from an object bearing a bar code symbol, manually activates the scanner to initiate reading and then moves the scanner over other objects bearing symbols to be read. Prior art trigger-operated bar code readers are disclosed in U.S. Pat. Nos. 4,387,297 to Swartz; U.S. Pat. No. 4,575,625 to Knowles; U.S. Pat. No. 4,845,349 to Cherry; U.S. Pat. No. 4,825,057 to Swartz, et al.; U.S. Pat. No. 4,903,848 to Knowles; U.S. Pat. No. 5,107,100 to Shepard, et al.; U.S. Pat. No. 5,080,456 to Katz, et al.; and U.S. Pat. No. 5,047,617 to Shepard, et al. Automatic laser-based bar code symbol reading systems are disclosed in U.S. Pat. No. 4,639,606 to Boles, et al., and U.S. Pat. No. 4,933,538 to Heiman, et al. Several hand-held scanners have been developed to provide “omnidirectional” scanning, so as to permit reading of a bar code irrespective of its specific orientation within the scanning pattern. Examples of such systems include the NCR 7890 presentation scanner from the NCR Corporation and the LS9100 omnidirectional laser scanner from Symbol Technologies, Inc. Although these systems provide both hands-free as well as hands-on modes of operation, each of these systems suffers from a number of shortcomings. In particular, the spatial extent of the scan pattern produced from these scanners frequently results in the inadvertent scanning of code symbols on products placed near the scanner during its hands-free mode of operation. On the the other hand, in the hands-on mode of operation, it is virtually impossible to use these scanners to read bar code symbol menus provided in diverse application environments. In each of these scanner designs, the scanner is tethered to its base unit by a power/signal cord, and the user is required to handle the scanner housing in an awkward manner in the hands-on mode of operation, resulting in strain and fatigue and thus a decrease in productivity. In addition, the control structure provided in each of these hand-held projection scanners operates the scanner components in a manner which involves inefficient consumption of electrical power, and prevents diverse modes of automatic code symbol reading which would be desired in many portable scanning environments. Hand-held scanners are not convenient to use in assembly-line applications where the user processes bar coded objects over an extended period of time, or where the user requires the use of both hands in order to manipulate objects. In other applications, hand-held scanners are difficult to manipulate while simultaneously moving objects or performing other tasks at a point-of-sale terminal. Stationary scanners, on the other hand, provide a degree of flexibility in many applications by allowing the user to manipulate bar coded objects with both hands. However, by their nature, stationary laser scanners render scanning large, heavy objects a difficult task, as such objects must be manually moved into or through the laser scan field. One type of stationary scanner is frequently mounted within a checkout counter of a supermarket or other retail point-of-sale environment. Such “in-counter” or “presentation” scanners could also be employed in conjunction with conveyors at a factory assembly line. These scanning systems include a scanning window or aperture at the top of the scanner housing through which a scanning pattern is projected. The scanning pattern is typically provided in the form of a plurality of multi-directional scanning lines. When an item bearing a bar code is brought into the field of the scan pattern so that at least one of the scanning lines completely traverses the bar code, light is reflected from the bar code and received back through the window. Stationary in-counter and presentation scanners use a variety of optical configurations to develop omnidirectional scanning patterns. These omnidirectional patterns are intended to ensure that at least one scanning line will cross a bar code symbol to be read, irrespective of the bar code's orientation within the scanning pattern. Examples of omnidirectional scanning patterns include comb patterns, orthogonal patterns, interlaced patterns, star-like patterns, lissajous patterns, and the like. While such scanners may be suitable for certain applications, the physical configuration of the optical components necessary to produce such complex omnidirectional patterns has resulted in scanner housings which are quite large and bulky. Moreover, the window of a counter-top or presentation scanner generally faces in a single, fixed direction. To change the direction of the scanning window and, thus, the orientation of the scanning pattern, it is necessary to relocate the entire housing. In many applications, this is inconvenient, especially when there is limited counter space. One example of a stationary scanner, disclosed in U.S. Pat. No. 4,713,532, produces a scanning pattern having three groups of intersecting lines. These line groups form a large “sweet spot” which permits substantially omnidirectional reading of bar codes. The '532 scanner has a compact housing with a relatively small footprint, and is mountable on or in a counter. Depending upon the orientation of the window, the scanning pattern may be projected horizontally, vertically, or at an angle. An example of a scanner constructed in accordance with the '532 patent is the MS260 scanner, available from Metrologic Instruments of Blackwood, N.J. However, once the scanner was mounted in a given orientation, it was fixed and could not be easily moved. Another example of a stationary scanner is disclosed in U.S. Pat. No. 5,216,231. This scanner is mountable on an adjustable base positioned above a counter. The base is constructed to permit the scanner housing to be adjusted in any of a variety of directions so that the scanning pattern will be projected at a desired orientation with respect to the counter. However, the base must be permanently secured to the countertop, which prevents the scanner from being lifted by hand to scan large or bulky items which do not fit on the countertop. An attempt to combine the advantages of a hand-held scanner and a stationary scanner, U.S. Pat. No. 5,767,501 describes a hand-held scanner mounted in the head of a hand-supportable housing. The housing can also be supported in a separate base for hands-free presentation or countertop scanning. The base unit is mountable to a counter, and is equipped with a pivoting receptacle. The pivoting receptacle permits the scanning window and, hence, the scanning pattern, to be adjustable about a horizontal axis. Unfortunately, the user must return the hand-supportable housing to the base unit after each scan, requiring a realignment of the handle and handle receiving portions. This realignment process becomes tedious and annoying with repeated use. Moreover, the base unit is large and cumbersome for use in many point-of-sale environments. Another attempt to combine the advantages of a hand-held scanner and a stationary scanner, U.S. Pat. No. 4,766,297 discloses a bar code scanning system which can be used in either a hands-on or hands-free mode of operation. The scanning system includes a portable hand-held laser scanning device for generating electrical signals corresponding to a scanned bar code symbol. In the hands-on mode of operation, a trigger is manually actuated each time the scanner operator wishes to read a bar code symbol on an object. The system also includes a fixture having a head portion for receiving and supporting the hand-held scanner, and a base portion above which the head portion is supported at a predetermined distance. In the hands-free mode of operation, the scanner is supported by the fixture head portion above the fixture base portion in order to allow objects bearing bar code symbols to pass between the head and base portions. In order to detect the presence of an object between the head and base portions, the fixture also includes an object sensor operably coupled to the scanner. When the object sensor senses an object between the head portion and the base portion, the sensor automatically causes the scanner, while supported in the fixture, to read the bar code symbol on the detected object. Whereas bar code symbol scanning systems of the type disclosed in U.S. Pat. No. 4,776,297 permit reading of printed bar code information using either a portable (hands-on), or stationary (hands-free) mode of operation, such systems suffers from several significant drawbacks. For example, assume that it is desired to scan a large, heavy object such as an 80-lb. bag of concrete. The scanner operator could use the scanner in the hands-on mode of operation, but they would need to manually actuate a trigger each time the bar code symbol is to be read. If the scanner operator needs to move the bag into position, this is a two-handed job in itself, and the task of manipulating a trigger on the scanner during this positioning process is cumbersome and tedious at best. On the other hand, in the hands-free mode of operation, the heavy bag must be passed between the head and base portions of the fixture. If the bag will not fit between the head and the base portions, then one must resort to triggered operation. Another scanning configuration is disclosed in U.S. Pat. No. 5,479,002. A scan head is adjustably mounted in a ball-and-socket joint on a scan module or housing. The scan head is movable about three mutually orthogonal axes, so as to allow the operator to steer the light beam emitted from the head. However, the '002 patent does not disclose or suggest any technique for combining the scan head and lower housing into a single package that is conveniently hand-held, but that can also be used as a free-standing scanner. Moreover, the design of the '002 housing is directed to a single-line scanning pattern and would not lend itself to production of an omnidirectional scanning pattern. Additional attempts to produce omnidirectional scanners having adjustable housings or bases include the Model LS9100 Scanner, available from Symbol Technologies, and the Duet Scanner, available from PSC. Unfortunately, both of these scanners require the user to remove the hand-held scanner from a stand for hand-supported scanning. Thus, there is a great need in the bar code symbol reading art for a bar code symbol reading system which overcomes the above described shortcomings and drawbacks of prior art devices and techniques, while providing greater versatility in its use. A need remains for a scanner configuration that is adjustable about one or more axes with respect to the base, but that does not entail the inconvenience of a separate scanner and stand. This configuration would permit omnidirectional bar code scanning from a hands-free standing position on a countertop or work surface, as well as from a hand-supported position for scanning large, heavy, or bulky items without requiring the scanner operator to repeatedly remove and/or replace the scanner in its stand. OBJECTS AND SUMMARY OF THE INVENTION It is an object of the invention to provide a bar code scanner that is mechanically rugged, so as to endure environmental shock and applied mechanical stresses such as drops and bumps. It is a further object of the invention to provide a self-standing bar code scanner that need not be permanently mounted to a work surface. It is a still further object of the invention to provide a bar code scanner which occupies a relatively small footprint on a work surface. It is another object of the present invention to provide a bar code scanner that can operate in a hands-free mode, and can also be picked up with a single hand. It is a further object of the invention to provide a bar code scanner with an omnidirectional scanning pattern so as to permit reading of bar codes presented to the scanner. It is a still further object of the invention to provide a bar code scanner with an omnidirectional scanning pattern so as to permit reading of bar codes that are passed through the scanning pattern. It is another object of the invention to provide an automatic bar code symbol reading system having an automatic hand-supportable laser scanning device which can be used at a point-of-sale (POS) station as either a portable hand-supported laser scanner when operated in its automatic hands-on mode of operation, or as a stationary laser projection scanner when operated in its automatic hands-free mode of operation. It is another object of the present invention to provide such an automatic bar code symbol reading system, wherein a highly collimated laser scanning pattern is projected about a projection axis, and comprises scanning planes which intersect within a confined scanning volume extending about the projection axis so that bar code symbols disposed within the scanning volume can be read omnidirectionally, while inadvertent scanning of bar code symbols outside of the scanning volume is prevented. It is another object of the present invention to provide such an automatic bar code symbol reading system, wherein the confined scanning volume is substantially symmetrically disposed about an axis perpendicular to the plane of the scanner window. Another object of the present invention to provide an automatic hand-supportable omnidirectional scanner with a hand-supportable housing that allows to user to easily control the direction of its projection axis by way of the outer casing of the housing, and thus align the narrowly confined scanning volume; of the scanner with the bar code symbol on the object to be scanned and identified. Another object of the present invention to provide a portable automatic hand-supportable omnidirectional laser projection scanner with a power-conserving control system that provides battery power to the system components of the scanner in an intelligent manner. Another object of the present invention to provide an automatic hand-supportable omnidirectional scanner with a housing that visually, indicates the direction of the projection axis, for intuitive hand-supported omnidirectional scanning of bar code symbols within the confined scanning volume extending thereabout. It is another object of the present invention to provide such an automatic bar code symbol reading system, in which one or more bar code symbols on an object can be automatically read in a consecutive manner. A further object is to provide such an automatic bar code symbol reading device, in which the hand-supportable bar code scanner has an infrared light object detection field which spatially encompasses at least a portion of its volumetric scanning field along the operative scanning range of the device, thereby improving the laser beam pointing efficiency of the device during the automatic bar code reading process. Another object of the present invention is to provide an automatic bar code symbol reading system, in which battery power from a supply within the housing is automatically metered out and provided to the power distribution circuitry thereof for a predetermined time period which is reset upon the occurrence of either the manual actuation of an externally mounted power reset button, the reading (i.e. scanning and decoding) of a valid bar code symbol, or the placement of the hand-supportable bar code symbol reading device on a work surface and/or counter top. A further object of the present invention is to provide such an automatic bar code symbol reading device, with a novel automatic power control circuit that effectively conserves the consumption of battery power therein, without compromising the operation, or performance of the device during its diverse modes of automatic operation. It is another object of the present invention is to provide an automatic hand-supportable bar code reading device having both long and short-range modes of bar code symbol reading, automatically selectable in a variety of different ways, (e.g. by placing the hand-supportable device on a countertop or work surface, or removing it therefrom). Another object of the present invention is to provide such a multi-mode automatic bar code symbol reading device, so that it can: be used in various bar code symbol reading applications, such as, for example, charge coupled device (CCD) scanner emulation, counter-top projection scanning in the hands-free long-range mode of operation, or the like. Another object of the present invention is to provide an automatic hand-supportable bar code reading device with a programmably selectable mode of operation that prevents multiple reading of the same bar code symbol due to dwelling of the laser scanning beam upon a bar code symbol for an extended period of time, yet allows a plurality of bar code symbols (e.g. representing the same UPC) to be read in a consecutive manner even though they are printed on the same, or apparently the same, object or surface, as often is the case in inventory scanning applications. A further object of the present invention is to provide a point-of-sale station (POS) incorporating the automatic bar code symbol reading system of the present invention. It is a further object of the present invention is to provide an automatic hand-supportable bar code reading device having a control system which has a finite number of states through which the device may pass during its automatic operation, in response to diverse conditions automatically detected within the object detection and scanning fields of the device. Another object of the present invention is to provide a portable, automatic bar code symbol reading device, wherein the laser beam scanning motor is operated at a lower angular velocity during its object detection state to conserve battery power consumption and facilitate rapid steady-state response when the device is induced into its bar code symbol detection and bar code symbol reading states of operation. Another object of the present invention is to provide a portable automatic bar code symbol reading device, wherein the laser beam scanning motor is denergized during its object detection state to conserve battery power consumption, and is momentarily overdriven to facilitate rapid steady-state response when the device undergoes a transition from the object detection state to the bar code symbol detection state of operation. Another object of the present invention is to provide a novel mechanism for mounting a projection laser scanning platform within the housing of an automatic hand-supportable omnidirectional projection laser scanner. Another object of the present invention is to provide a novel omnidirectional laser scanning platform for use within an automatic portable projection laser scanner. Another object of the present invention is to provide a bar code symbol reading system having at least one hand-supportable bar code symbol reading device which, after each successful reading of a code symbol, automatically synthesizes and then transmits a data packet to a base unit positioned within the data transmission range of the bar code symbol reading device, and upon the successful receipt of the transmitted data packet and recovery of symbol character data therefrom, the base unit transmits an acoustical acknowledgement signal that is perceptible to the user of the bar code symbol reading device residing within the data transmission range thereof. A further object of the present invention is to provide such a system with one or more automatic (i.e., triggerless) hand-supportable laser-based bar code symbol reading devices, each of which is capable of automatically transmitting data packets to its base unit after each successful reading of a bar code symbol. A further object of the present invention is to provide such a bar code symbol reading system in which the hand-supportable bar code symbol reading device can be used as either a portable hand-supported laser scanner in an automatic hands-on mode of operation, or as a stationary laser projection scanner in an automatic hands-free mode of operation. A further object of the present invention is to provide such a bar code symbol system in which the base unit contains a battery recharging device that automatically recharges batteries contained in the hand-supportable device when the hand-supportable device is supported within the base unit. It is another object of the present invention to provide such an automatic bar code symbol reading system with a mode of operation that permits the user to automatically read one or more bar code symbols on an object in a consecutive manner. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which a plurality of automatic hand-supportable bar code symbol reading devices are used in conjunction with a plurality of base units, each of which is assigned to a particular bar code symbol reading device. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which radio frequency (RF) carrier signals are used by each hand-supportable bar code symbol reading device to transmit data packets to respective base units. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which a novel data packet transmission and reception scheme is used to minimize the occurrence of data packet interference at each base unit during data packet reception. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which the novel data packet transmission and reception scheme enables each base unit to distinguish data packets associated with consecutively different bar code symbols read by a particular bar code symbol reading device, without the transmission of electromagnetic-based data packet acknowledgment signals after receiving each data packet at the base unit. It is a further object of the present invention to provide an automatic hand-supportable bar code reading device having a control system which has a finite number of states through which the device may pass during its automatic operation, in response to diverse conditions automatically detected within the object detection and scan fields of the device. It is yet a further object of the present invention to provide a portable, fully automatic bar code symbol reading system which is compact, simple to use and versatile. Yet a further object of the present invention is to provider a novel method of reading bar code symbols using an automatic hand-supportable omnidirectional laser scanning device. These and other objects of the present invention are realized in the form of an improved counter-top bar code scanner that is equipped with a bump protection mechanism and a scan angle adjustment mechanism. The bump protection mechanism is provided in the form of a protective sheath fabricated of a shock-absorbing material. The scan angle adjustment mechanism is provided in the form of a movable bracket adjustably mounted to the scanner housing. The bracket permits adjustment of the housing relative to the bracket. For example, if the bracket is mounted to a fixed surface, the bracket remains fixed but permits adjustments of the housing to any of a plurality of positions relative to the fixed surface. According to one preferred embodiment of the invention, the movable bracket permits adjustment of the housing to at least any of the two positions along an axis of rotation. In this manner, the coverage area of the scanning pattern may be adjusted and/or resituated. When the movable bracket is rested upon a work surface or countertop, the scanner operates in an automatic, hands-free mode. When the scanner and movable bracket are lifted from the work surface or countertop, the scanner operates in an automatic, hand-held mode. The scanning pattern permits reading of bar codes presented to the scanner, as well as bar codes that are passed through the scanning pattern. Taken together, the bar code scanner housing and bracket provide a self-standing bar code scanner that need not be permanently mounted to a work surface. Pursuant to a further embodiment of the invention, the shock-absorbing encasement is removable to permit cleaning and/or replacement of the material, and/or to permit servicing of the bar code scanner. In this manner, the invention provides a rugged bar code symbol reading system having an automatic hand-supportable scanning device which can be used at a point-of-sale (POS) station as either a portable hand-supported laser scanner, or as a stationary laser projection scanner. This configuration permits omnidirectional bar code scanning from a hands-free standing position on a countertop or work surface, as well as from a hand-supported position for scanning large, heavy, or bulky items without requiring the scanner operator to remove and/or replace a scanner in a stand. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the Objects of the Invention, the Detailed Description of the Preferred Embodiments of the Invention should be considered in conjunction with the accompanying drawings. FIG. 1 is a perspective view of a multi-purpose bar code scanner that is hand-supportable, free-standing, and/or mountable, the scanner having a housing that is adjustably mounted to a movable bracket, wherein the housing and movable bracket are configured according to a first embodiment of the invention, the housing including a substantially omnidirectional laser scanning platform mounted therein. FIG. 2 is an exploded perspective view of the bar code scanner housing of FIG. 1 showing the scanner housing about to be placed into the movable bracket. FIG. 3 is an exploded perspective view of the bar code scanner housing of FIG. 1 showing an encasement fabricated of shock-absorbing material about to be applied to the scanner housing. FIG. 4 is a side view of the bar code scanner housing of FIG. 3 wherein the encasement includes one or more notched projections so as to facilitate removal and/or installation of the encasement on the scanner housing. FIG. 5 is a perspective view of a multi-purpose bar code scanner that is hand-supportable, free-standing, and/or mountable, wherein the housing is configured according to a second embodiment of the invention and includes a substantially omnidirectional laser scanning platform mounted therein. FIG. 6 is a rear view of the bar code scanner of FIG. 5. FIG. 7 is a side view of a circular housing bumper which may be used in conjunction with the bar code scanner of FIG. 5. FIG. 8 is an exploded perspective view of the bar code scanner of FIG. 5. FIG. 9 is an exploded perspective view of the bar code scanner of FIG. 5 showing a cross-sectional view of an illustrative base unit. FIG. 10 is a side cross-sectional view of the scanning head of the bar code scanner of FIG. 5 showing the configuration of various optical components mounted therein. FIG. 11 is side view of a substantially omnidirectional laser scanning platform which may be mounted within the housing of the bar code scanner of FIG. 1 and/or the housing of the bar code scanner of FIG. 5. FIG. 12 is a front view of the bar code scanner of FIG. 5 showing a first illustrative layout for various optical components mounted therein. FIG. 13 is a front view of the bar code scanner of FIG. 5 showing a second illustrative layout for various optical components mounted therein. FIG. 14 is a perspective view of an illustrative base unit into which the bar code scanner of FIG. 5 may be mounted. FIG. 15 is an exploded perspective view of the bar code scanner of FIG. 1. FIG. 16 is a perspective view of a substantially omnidirectional laser scanning platform which may be mounted within the housing of the bar code scanner of FIG. 1. FIG. 17 is a detailed perspective view of the VLD block shown in FIG. 16. FIG. 18 is an electrical block diagram showing a first hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. FIG. 19 is an electrical block diagram showing a second hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. FIG. 20 is an electrical block diagram showing a third hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. FIG. 21 is an electrical block diagram showing a fourth hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. FIG. 22 is a top view of the guide plate shown in FIGS. 8 and 9. FIG. 23 is a side view of the guide plate of FIG. 22. FIG. 24 is a side view of the slide rail shown in FIG. 9. FIG. 25 is a top view of the slide rail shown in FIG. 24. FIG. 26 is a front view of the slide rail 70 shown in FIGS. 24 and 25. FIG. 27 is a perspective view of the optical bench of FIGS. 10 and 11 stripped of optical components. FIG. 28 is a top view of the light collecting mirror shown in FIG. 10. FIG. 29 is a side view of the optical bench of FIGS. 10 and 11. FIG. 30 is a front view of the scanner of FIG. 5 showing the omnidirectional scanning pattern at the face of the unit. FIG. 31 is a front view of the scanner of FIG. 5 showing the omnidirectional scanning pattern at approximately 2.5 inches away from the face of the unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a multi-purpose bar code scanner 1001 that is hand-supportable, free-standing, and/or mountable, wherein the scanner is configured according to a first embodiment of the invention. The scanner has a housing 1007 that is adjustably mounted to a movable bracket 1005, in the sense that bracket 1005 is movable relative to housing 1007. Accordingly, if movable bracket 1005 is mounted to a fixed surface such as a countertop, the movable bracket 1005 will remain fixed, but will permit adjustment of housing 1007 to any of a plurality of positions. One or more of these positions aim a window 1027 of housing 1007 towards the countertop surface and/or a point-of-sale area. Housing 1007 is equipped with a shock-absorbing mechanism in the form of protective sheath 1003. Protective sheath 1003 may be fabricated of rubber, flexible plastic, and/or any of various other materials capable of absorbing mechanical shock. Protective sheath 1003 may be fabricated so as to permit removal of the sheath from housing 1007, or, alternatively, the sheath could be designed as a permanent part of housing 1007. Protective sheath 1003 functions to protect bar code scanner 1001 against damage if the unit is dropped or banged. In addition to protecting window 1027 from damage, protective sheath 1003 also protects the four upper and four lower corners of the approximately cube-shaped bar code scanner 1001 of FIG. 1. Housing 1007 includes a substantially omnidirectional laser scanning platform mounted therein, which will be described hereinafter with reference to FIGS. 11-13 and 15-21. This omnidirectional laser scanning platform projects a substantially omnidirectional scanning pattern through window 1027. Optionally, housing 1007 may also be provided with top-mounted, front-mounted, or side-mounted LED power and/or LED “good read” indicators. Housing 1007 is preferably molded of hard plastic or the like, and can be formed in two half-sections with tongue-and-groove edges for an interlocking fit. Window 1027 is generally square and/or rectangular in configuration and mounted in an aperture of housing 1007. Illustratively, window 1027 could be seated in, and/or held by, one or more grooves or projections formed in housing 1007. Window 1027 may be fabricated of a square and/or rectangular section of transparent acrylic-type plastic with optical filtering properties such as described in detail in U.S. Pat. No. 5,627,359, which patent is commonly owned by Metrologic Instruments, Inc. and incorporated herein by reference. In the example of FIG. 1, movable bracket 1005 includes a position adjustment mechanism providing position adjustment of the housing 1007 relative to the bracket 1005 about rotational axis a-a′. This position adjustment mechanism is provided in the form of an annular flange 1009 having an inner diameter 1011 and an outer diameter 1013. Along the interior (inner) surface of annular flange 1009, between inner and outer diameters 1011 and 1013, are provided one or more projections, notches, ridges, grooves, nubs, fingers, detents, and/or bosses that engage one or more corresponding mating structures (such as projections, notches, ridges, grooves, nubs, fingers, detents, and/or bosses) on housing 1007, as will be described in greater detail with reference to FIG. 2. FIG. 2 is an exploded perspective view of the bar code scanner housing of FIG. 1 showing scanner housing 1007 about to be mounted to movable bracket 1005. Attention is directed to annular flange 1009. Along the interior (inner) surface of annular flange 1009, between inner and outer diameters 1011 and 1013, are provided one or more projections 1017 (in this example, rounded teeth), that engage one or more corresponding mating structures (in this example, rounded grooves 1015) of housing 1007. Also, observe that movable bracket 1005 includes two mounting holes 1019, 1021 for mounting to a surface such as a countertop and/or point of sale terminal. FIG. 3 is an exploded perspective view of the bar code scanner housing of FIG. 1 showing a protective sheath 1003 about to be applied to scanner housing 1007. In the example of FIG. 3, this protective sheath 1003 is a removable and reinstallable encasement fabricated of a shock-absorbing material such as rubber. FIG. 4 is a side view of the bar code scanner housing of FIG. 3 wherein protective sheath 1003 includes one or more projections 1023 and mating notches 1025 so as to facilitate quick and easy removal and/or installation of protective sheath 1003 on housing 1007. Use of these projections 1023 and notches 1025 is optional. The protective sheath 1003 shown in FIGS. 1-3 can be removed and reinstalled from housing 1007 without the use of any projections or notches. Refer now to FIG. 5, which is a perspective view of a multi-purpose bar code scanner 10 that is hand-supportable, free-standing, and/or mountable. The scanner includes a housing that is configured according to a second embodiment of the invention and has a substantially omnidirectional laser scanning platform mounted therein. Scanner 10 includes a scanning head 12 that is rotationally connected to a base unit 60. Scanning head 12 houses various associated optical components of the omnidirectional laser scanning platform as will be described in greater detail hereinafter. FIGS. 5 through 8 set forth the general construction of the scanner housing. Scanning head 12 has an aperture 11 through which a substantially omnidirectional scanning pattern is projected. Scanning head 12 is formed in a generally spherical configuration with a flat front window 14 and top-mounted LED power and good read indicator 50. Head unit 12 is preferably molded of hard plastic or the like, and can be formed in two half-sections with tongue-and-groove edges for an interlocking fit. Scanning window 14 is generally round in configuration and mounted in a circular housing bumper 20, which is in turn mounted in aperture 11 of scanning head 12. As shown in FIG. 7, window 14 is seated at an angle within a groove (not shown) formed in housing bumper 20. Housing bumper 20 has a beveled outer lip 26 and an inner lip 24 with a channel 25 formed therebetween. Channel 25 engages the inner edge of the aperture 11 of the scanning head 12. Additionally, the housing bumper has a pair of locking rib members 23 which further engage a corresponding protrusion 21 on the interior of scanning head 12 (refer to FIG. 10). The combination of channel 25 and locking rib members 23 acts to secure the window 14 and the housing bumper 20 to the scanner housing 10. Housing bumper 20 acts to protect the front of the scanner head 12 and to cushion the scanning window 14 against damage if the unit dropped or banged. Window 14 is a round section of transparent acrylic-type plastic with optical filtering properties such as described in detail in U.S. Pat. No. 5,627,359, which patent is commonly owned by Metrologic Instruments, Inc. and incorporated herein by reference. The size and shape of the scanning window and housing bumper can be varied from the specific size and/or shape shown without changing the performance of the scanner. FIG. 6 is a rear view and FIG. 8 is an exploded view of the scanner 10 of FIG. 5 in which the enhanced ergonomics of the design are apparent. Base unit 60 has a contoured top opening 61 for receiving a neck portion 16 of the substantially spherical scanning head 12. The contour of the opening 61 is curved upward to provide ergonomic support for the spherical scanning head 12 and an aesthetically pleasing scanner 10 (as was shown and claimed in Applicant's corresponding U.S. Design Pat. No. D 408,806). The bottom portion of base unit 60 has contoured lateral recesses 15 and 17 on opposing sides to provide thumb and finger grips as shown in FIG. 6. During hand-supported operation of scanner 10, the user can easily grip scanner 10 in one hand by the contoured lateral recesses 15 and 17 and lift it off of a countertop surface to scan a large or bulky item. FIG. 8 details the component parts of the scanner housing and their assembly into scanner 10. As shown, neck portion 16 of scanning head 12 is inserted into the contoured opening 61 in base unit 60. Base unit 60 rotationally supports head unit 12 and houses a printed circuit board (“PC board”) which includes electronics for implementing functions related to the digitizing, decoding, formatting and transmitting of bar code symbol character data produced in scanning head 12. If some of these electronic elements are not mounted in scanning head 12, these circuit elements can be located on an optional PC board mounted in base unit 60. Scanning head 12 can be pivoted about a horizontal axis with respect to base 60, thereby allowing a user to position scanning window 14, and the projected scan pattern, along any of a plurality of directions. Neck portion 16 of scanning head 12, once inserted into base unit 60, rests atop two opposing guide-rails 70 mounted on the interior side walls of base unit 60. Guide rails 70 snap fit onto correspondingly-shaped protrusions 71 formed in interior side walls of base unit 60. Guide rails 70 are formed of smooth plastic and provide direct support and cushioning for scanning head 12. The underside of neck 16 has a pair of arcuate indentations 22 on opposite sides of the neck. Guide rails 70 are curved to conform to indentations 22 on the underside of neck 16 and in general to the spherical outer surface of scanning head 12. FIGS. 24, 25 and 26 are a side view, top view and front view, respectively, of the right-side guide rail 70 which is exemplary of both guide rails. Guide rail 70 is an arcuate bracket that snap fits onto a correspondingly-curved protrusion 71 formed on the interior side walls of scanning head 12 via a groove 77 formed along bottom edge of guide rail. Each guide rail 70 has a planar side-wail portion 72, a front spacer bracket 78, a reinforcing rib 76, and an arcuate slide rail 74 protruding laterally from bottom edge of each side-wall portion 72. Slide rail 74 is exterior of groove 77. Once groove 77 has been fitted to protrusion 71, slide rail 74 extends into the center of base unit 60. When guide rails 70 are attached to the interior of base unit 60, opposite each other, they provide slidable support for neck portion 16 and the scanning head. Indentations 22 formed in the side of neck portion 16 rest on slide rails 74. The exterior spherical surface 27 of scanning head 12 rests on the upper edge of side-wall portion 72 of guide rails 70. When scanning head 12 is rotated about a horizontal axis, indentations 22 in neck 16 slide against slide rails 74 of guide rails 70. The front spacer bracket 78 and reinforcing rib 76 further act to support, position and cushion scanning head 12 on base unit 60. With reference to FIGS. 8 and 9, a guide plate 40 attaches to the underside of neck portion 16, and guide plate 40 traverses opposing guide rails 70 to moveably connect scanning head 12 to base unit 60, thereby pivotally securing scanning head 12 to base unit 60. FIGS. 22 and 23 are a top view and a side view, respectively, of guide plate 40. Although guide plate 40 is shown in FIGS. 8 and 9 as intended for use with the scanner of FIG. 5, a guide plate 40 may also be used in conjunction with the scanner of FIG. 1. Guide plate 40 is a substantially rectangular panel that has a pair of parallel tabs 42 and 48, front and back, that fit within corresponding notches 43 on the underside of neck 16 to position guide plate 40, and two screw holes 45 to facilitate screw attachment to neck 16. Openings 46 and 47 allow for the pass through of electrical connections. With respect to the scanner of FIG. 5, during rotation of scanning head 12, guide plate 40 similarly slides against underside of slide rails 74 identical to the movement of the underside of neck 16 against the top side of slide rails 74. When neck 16 is seated on seated on guide rails 70, indentations 22 rest against slide rails 74 and the neck fits snugly between guide rails 70. During rotation of the scanning head, guide rails 70 provide both lateral and elevational support for scanning head 12. This support by guide rails 70 prevents the outside of scanning head 12 from constantly brushing against the curved opening 61 of base unit 60, which in turn keeps the outside surface of scanning head 12 from being scratched by the repetitive motion of rotating head 12 with respect to base unit 60. FIG. 14 is a perspective view of base unit 60 with guide rails 70 installed therein. Note that this base unit 60 is used in conjunction with the scanner of FIG. 5, and not with the scanner of FIG. 1. The curved configuration of guide rails 70 and opening 61 provides a first pivot point of radius r1 extending from contoured opening 61 of base unit 60 about the horizontal axis of head unit 12, and a second pivot point of radius r2 extending from guide rails 70 to the same horizontal axis of head unit 12. This dual-radius orbiting support configuration results in an extremely rugged and durable scanning unit in which scanning head 12 pivots easily about a horizontal axis with little or no friction against base unit 12. When used as a fixed scanner, base unit 60 provides a well-balanced, stable and protected foundation for head unit 12, and yet very little counter space is needed. Returning to FIG. 8, a bottom plate 80 is a substantially planar member that attaches to the underside of base unit 60 by four screws through screw holes 82, thereby sealing it off. Rubber feet can be secured to the underside of bottom plate 80 to cover the screw heads and to improve the footing of the scanner. Additional screw holes 84 may be provided as desired to allow for mounting the scanner in a fixed manner to a countertop, wall or other fixed position. Preferably, a collar 86 protrudes upwardly from bottom plate 80 and fits into an opening provided in base unit 60. Collar 86 has an opening 62 for the insertion of a power or communication cable. Bottom plate 80 and collar 86 are configured to fit flush with the bottom of base unit 60 with the collar 86 fitting snugly into opening 62. This configuration aids assembly and reinforces collar 86 to provide a rugged passage for electrical cabling. The bottom plate 80 additionally provides support for an optional second PC board (not shown) which holds circuitry for any of the digitizing, decoding, formatting and transmitting of bar code symbol character data. Cabling also connects an analog signal processing board 52 (to be described) that is mounted in scanner head 12 to a signal decoding board in base unit 60. The cables are passed through openings formed in neck portion 16 of scanning head 12 and guide plate 40. The compact scanner housing configurations set forth in FIGS. 1 and 5 yield convenient, durable and ergonomic scanner packages having scanning heads 12 that can be tilted vertically about a 30 degree angle with respect to base unit 60, and/or a fixed surface such as a countertop. Thus, these scanners are structurally capable of implementing a relatively aggressive omnidirectional scanning pattern from a free-standing fixed position atop a counter, from a fixed mounting position at a point of sale terminal, or while handheld by a user. The flexibility of the housing as described above is matched by an aggressive and reliable omnidirectional laser scanning platform. The same omnidirectional scanning platform could, but need not, be employed in the bar code scanner designs of FIGS. 1 and 5. The scanning platform, inclusive of all associated optical and electrical components, is mounted within the head unit 12 and projects a pattern of scan lines through front window 14 onto a bar code to be read. FIGS. 30 and 31 show the omnidirectional scanning pattern as it is projected at the light transmission window and 2.5 inches from the window of the bar code scanner of FIG. 1. A substantially similar pattern is projected by the scanner of FIG. 5, but the window of FIGS. 30 and 31 would then be shown as rectangular or square instead of circular. The omnidirectional laser scanning platform of the present invention may employ an optical layout that is substantially similar to any of the optical layouts shown in U.S. Pat. Nos. 5,637,852 and 5,844,227, the entire disclosures of which are incorporated by reference herein. As shown in FIGS. 10-12 and 15-18, an exemplary laser scanning platform according to the present invention may be mounted within housing 1007 of bar code scanner 1001 of FIG. 1, and/or head portion 12 of scanner housing 10 of FIG. 5. With reference to FIGS. 10-12, showing the laser scanning platform mounted in the scanner of FIG. 5, the platform includes subcomponents assembled upon an optical bench 34 with respect to a central longitudinal reference plane. Substantially identical components are used in the scanning platform that is mounted within the scanner of FIG. 1, except that these components would be mounted to the interior of an enclosure having a cubic volume instead of a spherical volume. As shown in FIG. 10, the subcomponents assembly includes: a scanning polygon 36 having four light reflective surfaces 36A, 36B, 36C and 36D, each disposed at a tilt angle with respect to the rotational axis of the polygon; an electrical motor 37 mounted on the optical bench and having a rotatable shaft on which polygon 36 is mounted for rotational movement therewith; an array of stationary mirrors 38A, 38B, 38C, 38D and 38E fixedly mounted with respect to the optical bench; a laser beam production module 39, fixedly mounted above the rotating polygon 36 for producing a laser beam having a circularized beam cross-section, and essentially free of astigmatism along its length of propagation; an analog signal processing board 52 fixedly over the rotatable polygon 36 and carrying a photodetector 51 for detecting reflected laser light and producing an analog signal, and signal processing control circuits 53 for performing various functions, including analog scan data signal processing; a light collecting mirror 33, disposed above the array of stationary mirrors 38 for collecting light rays reflected off the rotating polygon 36 and for focusing these light rays onto the photodetector 51 on the analog signal processing board 52; and a beam directing surface 32, realized as a flat mirror mounted on the light collecting mirror for directing the laser beam from the laser beam production module 39 to the rotating polygon 36 disposed there beneath. The laser beam production module of the present invention could be implemented by employing a system of a lens and aperture as is well known in the art, a system which employs a plurality of diffractive optical elements (DOEs) for modifying the size and shape of the laser beam. Various embodiments of DOE-based laser beam production modules are shown and described in co-pending patent application Ser. No. 09/071,512 filed on May 1, 1998, commonly owned by the applicant hereof and incorporated by reference herein. With reference to FIGS. 27, 28 and 29, the optical bench 34 is shown in greater detail, with the polygon 36, scanning motor 37, laser beam production module 39, collector mirror 33, and stationary mirror elements 38A through 38E removed for illustration purposes. As shown, stationary mirror brackets 44A through 44E are formed integral to the optical bench 34 for Mounting the stationary mirrors thereon. FIG. 27 is a top view of the light collecting mirror 33. The collector mirror 33 attaches to a collector bracket 35 by means of a pair of integrally-formed pivot arms 31 with distal hubs 29. The pivot arms 31 of collector mirror 33 snap fit into notches 30 formed in collector mirror bracket 35, and hubs 29 maintain the pivotal seating. With additional reference to FIG. 28, the beam directing surface 32 which is mounted to the collector mirror 33 must be aligned with the laser beam that is produced by the laser beam production module 39 during the manufacturing calibration process. Moreover, the collector mirror 33 must also be aligned for the efficient collection of returned light. The pivoting collector mirror 33 allows for easy and infinite adjustment of the collector mirror 33, and thus the beam directing surface 32, along the vertical direction during manufacturing. The snug fit between the bracket notches 30 and the pivot arms 31 of the mirror allows for an assembler to adjust the position of the mirror while preventing further unintentional movement of the mirror after the alignment is complete. Pursuant to an alternate embodiment, the collector mirror 33 is mounted for dual-axis adjustment. This is accomplished by mounting the collector mirror 33 in a rectangular mirror frame (not shown) with pivot points at top and bottom. The collector mirror frame itself has additional pivot arms on the sides for fitting into the notches 30 of mirror bracket 35 (similar to the pivot arms shown integral to mirror 33 in FIG. 28). This combination of pivot points both at the top and bottom of the mirror and on the sides of the mirror frame provides for adjustment of the mirror in both a right-to-left direction as well as the up-and-down direction provided for in the scanner embodiment detailed above. In both cases, the pivoting collector mirror 33 can be adjusted and calibrated at the factory. If desired, the pivot points of the collector mirror 33 can be fixed by gluing after calibration. Referring to FIGS. 11, 27 and 29, at the opposite end of the optical bench 34 the laser beam module support bench 41 is formed at a height above the mirror bracket array 44. This allows for mounting of the polygon 36 and rotating motor 37 below the laser beam production module 39. The laser beam production module 39 is mounted in the laser module mount bracket 28. The analog signal processing board 52 attaches to PC board bracket 54, above and behind the laser module mount bracket 28. The entire optical bench 34 may be implemented in the form of a single piece molded plastic unit, which holds some or all of the components that make up the omnidirectional laser scanning platform. Pursuant to one preferred embodiment of the invention, the collector mirror 33, beam directing surface 32, laser beam production module 39 and photodetector 51 are mounted above the polygon 36 and mirror array 38. However, it is within the scope of the invention to reverse the orientation of these components with respect to each other. FIGS. 15-18 illustrate the manner in which an exemplary laser scanning platform according to the present invention may be mounted within housing 1007 of bar code scanner 1001 of FIG. 1. The functional and operational details of this scanning platform, as well as various hardware implementations, were discussed above in connection with FIGS. 10-12 for the scanner design of FIG. 5. Many of these details remain substantially unchanged when the scanning platform is mounted in housing 1007 of FIG. 1. Substantially identical components are used in the scanning platform that is mounted within the scanner of FIG. 1, except that these components are mounted to the interior of an enclosure having a cubic volume instead of a spherical volume. Refer to FIG. 15, which is an exploded perspective view of the bar code scanner of FIG. 1. Housing 1007 (FIG. 1) has been disassembled by separating housing front 1501, including window 1027, from housing bottom 1509. An optical subcomponents assembly 1503 is provided, similar to the assembly previously described in connection with FIG. 11. The optical components assembly, to be described more particularly hereinafter with reference to FIG. 16, is mounted to a printed circuit (PC) board 1505. PC board 1505 includes a cable port 1507 which provides a communications interface to a processing mechanism, personal computer, local-area network, data storage device, or the like. To this end, cable port 1507 is adapted to accept a communications cable 1511. However, cable port 1507 and communications cable 1511 are shown for illustrative purposes only, as any communications technique for transmitting information from one location to another could be employed, including wireless communication, wired communication, and various combinations thereof. FIG. 16 is a perspective view of a substantially omnidirectional laser scanning platform which may be mounted within the housing of the bar code scanner of FIG. 1. More particularly, FIG. 16 provides a more detailed view of the optical subcomponents assembly 1503 described briefly in connection with FIG. 15. Optical subcomponents assembly 1503 includes a shock-absorption mechanism in the form of shock mounts 1601 and 1617. An optical bench 34 is provided, which was previously described in connection with FIGS. 10-12. A scanning polygon 36 is equipped with four light reflective surfaces. These surfaces are not shown in FIG. 16, but they are indicated as reference numerals 36A, 36B, 36C and 36D in FIGS. 10 and 11. Each of the four light reflective surfaces are disposed at a tilt angle with respect to the rotational axis of the polygon. An electrical motor 37 mounted on optical bench 34 has a rotatable shaft on which polygon 36 is mounted for rotational movement therewith. An array of stationary mirrors 1607 (five in the present example) are fixedly mounted with respect to optical bench 34; these mirrors correspond to reference numerals 38A, 38B, 38C, 38D and 38E of FIG. 12, but mirrors 38A and 38B have been cut away from the drawing of FIG. 16 for the purpose of clarity. A laser beam production module (shown in FIG. 17, reference numeral 1701) is fixedly mounted above the rotating polygon 36 for producing a laser beam having a circularized beam cross-section, and essentially free of astigmatism along its length of propagation. A signal processing board 1611 is fixedly mounted over rotatable polygon 36. This signal processing board 1611 carries a photodetector 1609 for detecting reflected laser light and producing an analog signal, and signal processing control circuitry for performing various functions, including analog scan data signal processing. A light collecting mirror 1603, disposed above the array of stationary mirrors 1607, collects light rays reflected off the rotating polygon 36 and focuses these light rays onto photodetector 1609 on signal processing board 1611. A beam directing surface, realized as a flat folding mirror 1605 mounted on, formed in, and/or mounted proximate to, light collecting mirror 1603 for directing the laser beam from the laser beam production module to the rotating polygon 36 disposed therebeneath. FIG. 17 is a detailed perspective view of an illustrative laser beam production module for use with the hardware configuration of FIG. 16. In the example of FIG. 17, this laser beam production module is provided in the form of a VLD (visible laser diode) 1701. However, it is not required to use a wavelength in the visible range. It is alternatively possible to use an infrared beam production module and/or an ultraviolet beam production module. However, visible light permits a human operator to view the scanning pattern as it is projected outwardly from window 1027 (FIG. 1) under certain circumstances. Having described the physical construction of the laser scanning platform of the present invention, it is appropriate at this juncture to describe the manner in which the laser scanning pattern is produced. A laser beam is produced from the laser beam production module (FIG. 12, 39; FIG. 17, 1701) and is directed towards the beam directing surface (FIG. 12, 32; FIG. 16, 1605) mounted on the light collector mirror (FIG. 12, 33; FIG. 16, 1603). The laser beam reflects from the beam directing surface 32, 1605 towards the mirrored facets on the rotating scanning polygon 36. As the polygon spins, the incident laser beam reflects off the rotating mirrors (36A through 36D of FIG. 11; 1607 of FIG. 16) and sweeps the laser beam about its rotational axis along a plurality of different paths which intersect the stationary array of mirrors 38A through 38E, 1607 on optical bench 34. During each revolution of the scanning polygon 36, the laser beam reflects off the rotating mirrors and is repeatedly swept across the array of stationary mirrors thereby producing first, second, third, fourth and fifth groups of plural scan lines, respectively. Each scan line in each group of scan lines is substantially parallel to each other scan line in that group of scan lines. The intersection of the groups of parallel scan lines produces a confined and/or collimated scanning pattern. The scan lines that make up this confined scanning pattern 13, as shown in FIGS. 30 and 31, are projected out through the light transmission window and intersect about a projection axis that extends outward from the light transmission window (FIG. 5, 14; FIG. 1, 1027) to produce a relatively confined scanning volume of substantially columnar, pyramidal, or frustral dimensions that may diverge slightly as distance to the scanning window increases. Within this collimated and/or confined scanning volume, a bar code symbol can be scanned omnidirectionally, while preventing unintentional scanning of code symbols on objects located outside of the scanning volume. When a bar code symbol on an object is presented to the confined scanning pattern 13 projected through a confined scanning volume the bar code symbol is scanned independent of its orientation in the scanning volume. At least a portion of the laser light reflected from the scanned code symbol is directed through the light transmission window (FIG. 5, 14; FIG. 1, 1027) reflected off the stationary array of mirrors 38, reflected off the rotating polygon 36, focused by the light collection mirror 33 (FIG. 12), 1603 (FIG. 16) onto photodetector 51 (FIG. 12), 1609 (FIG. 16), whereupon an electrical signal is produced for use in decode signal processing. The omnidirectional laser scanning platform of the present invention, as incorporated into any of the bar code scanners shown in FIGS. 1 and 5, can be automatically activated or can include manual activation means. Manual activation means can include a trigger or other switch located on the exterior of the scanner housing which when depressed activates the laser, the laser scanning mechanism, the photoreceiving circuitry and decoding circuitry. Laser bar code scanning systems employing manual activation means are well known in the art. Various embodiments of automatically-activated bar code symbol scanning systems are detailed in FIGS. 18, 19, 20 and 21. A number of the subsystems are common to all embodiments and are thus described in detail with respect to FIG. 18 only. However, the description of these subsystems applies similarly when they are included in other embodiments described herein. FIG. 18 is an electrical block diagram showing a first hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housings of any of the bar code scanners of FIG. 1 and/or FIG. 5. The automatically activated bar code symbol scanning system of this first hardware embodiment is composed of a number of subsystems: an infrared (IR) based object detection subsystem 112, as disclosed in U.S. Pat. Nos. 5,260,553, 5,340,971 and 5,808,285, incorporated herein by reference; a scanning means 111; a photoreceiving circuit 112; an analog-to-digital conversion circuit 113; a bar code presence detection subsystem 114 as disclosed in prior U.S. Pat. Nos. 5,484,992 and 5,616,908 incorporated herein by reference; a bar code scan range detection module 115; a symbol decoding module 116; a data format conversion module 117; a symbol character data storage unit 118; and a data transmission circuit 119. As illustrated, these components are operably associated with a programmable system controller 122 which provides a degree of versatility in system control, capability and operation. In accordance with the present invention, one purpose of the object detection subsystem is to perform the following primary functions during object detection: (i) automatically and synchronously transmitting and receiving pulse infrared (IR) signals within an IR-based object detection field; (ii) automatically detecting an object in at least a portion of the IR-based object field by analysis of the received IR pulse signals; and (iii) in response thereto, automatically generating a first control activation signal A1 indicative of such automatic detection of the object within the object detection field. As shown in FIG. 18, the first control activation signal A1 is provided to the system control subsystem 122 for detection, analysis and programmed response. As illustrated in FIG. 18, the scanning circuit 111 includes, a light source 147 which is shown as a solid state visible laser diode (VLD), but can be any source of intense light suitably selected for maximizing the reflectivity from the object's surface bearing a bar code symbol, a scanning mechanism 150 such as a rotating polygon which is mounted on a rotating motor driven by motor drive 151. To selectively activate the laser light source 147 and scanning mechanism 150, upon receiving control activation signal A1, the system controller provides laser diode enable signal E.sub.L scanning mechanism enable signal E.sub.M as input to driver circuits 148 and 151 respectively. When signals E.sub.L and E.sub.M are at a logical high level the VLD is activated and the beam is scanned through the light transmission aperture and across the scan field. When an object, such as a product bearing a bar code symbol, is presented within the scan field at the time of scanning, the laser beam incident thereon will be reflected. This will produce a laser light return signal of variable intensity which represents a spatial variation of light reflectivity characteristic of the spaced apart pattern of bars comprising the bar code symbol. Photoreceiving circuit 112 detects at least a portion of laser light of variable intensity, which is reflected off the object and bar code symbol within the scan field. Upon detection of this scan data signal, photoreceiving circuit 112 produces an analog scan data signal D.sub.1 indicative of the detected light intensity. Analog scan data signal D.sub.1 is provided as input to A/D conversion circuit 113. As is well known in the art, A/D conversion circuit 113 processes analog scan data signal D.sub.1 to provide a digital scan data signal D.sub.2 which resembles, in form, a pulse width modulated signal, where logical “1” signal levels represent spaces of the scanned bar code symbol and logical “0” signal levels represent bars of the scanned bar code symbol. A/D conversion circuit 113 can be realized by any conventional A/D chip. Digitized scan data signal D.sub.2 is provided as input to bar code presence detection module 114 and symbol decoding module 116. The bar code presence detection module performs the following functions during bar code symbol detection: (i) automatically generating an omnidirectional visible laser scanning pattern within the bar code symbol detection field defined relative to the scanner housing, to enable scanning of a bar code symbol on the detected object; (ii) automatically processing scan data collected from the bar code symbol detection field and detecting the presence of the bar code symbol thereon; and (iii) automatically generating a control activation signal A2=1 indicative thereof in response to the automatic detection of the bar code symbol. As shown in FIG. 18, the second control activation signal A2 is provided to the system controller 122 for detection, analysis and programmed response. The bar code presence detection module is to determine whether a bar code is present or absent from the scan field over a time interval specified by the system controller, by detecting a bar code symbol “envelop” from digital scan data signal D.sub.2 by analyzing the digital count and sign data in the signal. When a bar code symbol “envelop” is detected in the scan field, and the bar code presence detection module provides signal A2 to the system controller 122 which then causes the system to undergo a transition for the bar code presence detection state to the bar code reading state. Within the context of the system design shown in FIG. 18, the bar code symbol decoding module 116 performs the following functions during the bar code symbol reading state: (i) automatically generating an omnidirectional visible laser scanning pattern within the scan field, to enable scanning of the detected bar code symbol therein; (ii) automatically decode-processing scan data collected from the scan field so as to detect the bar code symbol on the detected object; 30 (iii) automatically generating a third control activation signal A3=1 indicative of a successful decoding operation, and producing decoded symbol character data representative of the detected and read bar code symbol. As shown in FIG. 18, the third control activation signal A3 is provided to the system controller 122 for detection, analysis and programmed response. Upon receiving control activation signal A3, the system controller 122 generates and provides enable signals E.sub.FC, E.sub.DS, and E.sub.DT to the data format conversion module 117, data storage unit 118, and data transmission circuit 119, respectively at particular stages of its control program. Symbol decoding module 116 provides decoded symbol character data D3 to data format module 117 to convert data D3 into two differently formatted types of symbol character data, namely D4 and D5. Format-converted symbol character data D4 is of the “packed data” format, particularly adapted for efficient storage in the data storage unit 118. Format-converted symbol character data D5 is particularly adapted for data transmission to data collection and storage device, or a host device such as a computer or electronic cash register. When format converted data D5 is to be transmitted to a host device, the system controller 122 will generate and provide enable signal E.sub.DT to data transmission circuit 119. Thereupon, data transmission circuit 119 transmits format-converted data D5 to the data collection or host device via the data transmission lines of flexible connector cable 125. FIG. 19 is an electrical block diagram showing a second hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. As shown in FIG. 19, an automatically activated bar code symbol scanning system constructed in accordance with this second embodiment is composed of a number of subsystems as well, namely an IR-based object detection subsystem 82; a laser-based bar code symbol detection subsystem 83; a laser-based bar code symbol reading subsystem 84; a data transmission subsystem 85; a state indication subsystem 86; a data transmission activation switch or control device 87A integrated with the scanner housing in part or whole; a mode-selection sensor 87B integrated with the scanner housing in part or whole; and a system control subsystem 88 operably connected to the other subsystems described above. In general, system 79 has a number of preprogrammed operational states, namely: an object detection state; a bar code symbol detection state; a bar code symbol reading state; and a data transmission state. Within the context of the hardware design shown in FIG. 19, the IR-based object detection subsystem 82 performs the following functions during the object detection state: (i) automatically and synchronously transmitting and receiving pulse infrared (IR) signals within an IR-based object detection field 89 defined relative to the scanner housing 10; (ii) automatically detecting an object in a least a portion of the IR-based object detection field 89 by analysis of the received IR pulse signals; and (iii) in response thereto, automatically generating a first control activation signal A1 indicative of such automatic detection of the object within the object detection field. As shown in FIG. 19, the first control activation signal A1=1 is provided to the system control subsystem 88 for detection, analysis and programmed response. When control activation signal A1=1 is received by the system controller the bar code symbol reading device is caused to undergo a state transition from bar code symbol detection state to bar code symbol detection state. This transition has been described in detail in connection with the embodiment shown in FIG. 18. As shown in the figures hereof; object detection, bar code detection and bar code reading fields 89, 90 and 91, respectively, have been schematically represented only general terms. For purposes of clarity, the specific characteristics of these fields have not been shown. Notably, however, such characteristics can be ascertained from the various references relating thereto which are identified and incorporated herein by reference. Within the context of the hardware design shown in FIG. 19, the laser-based bar code symbol detection subsystem 83 performs the following primary functions during the bar code symbol detection state: (i) automatically generating a visible laser scanning pattern of predetermined characteristics within the laser-based bar code (symbol) detection field 90, defined relative to the scanner housing (not shown), to enable scanning of a bar code symbol on the detected object; (ii) automatically processing scan data collected from the bar code symbol detection field 89 and detecting the presence of the bar code symbol thereon; and (iii) automatically generating a control activation signal A2=1 indicative thereof in response to the automatic detection of the bar code symbol. As shown in FIG. 19, the second control activation signal A2 is provided to the system control subsystem 88 for detection, analysis and programmed response. When second control activation signal A2 is provided to the system control subsystem 88, this causes the bar code symbol reading device to undergo a state transition from bar code symbol detection state to bar code symbol reading state. This transition has also been described in detail in connection with FIG. 18 above. Within the context of the hardware design shown in FIG. 19, the laser-based bar code symbol reading subsystem 84 performs the following functions during the bar code symbol reading state: (i) automatically generating an omnidirectional visible laser scanning pattern within the laser-based bar code symbol reading field 91 defined relative to the scanner housing, to enable scanning of the detected bar code symbol therein; (ii) automatically decode-processing scan data collected from the bar code symbol reading field 91 so as to detect the bar code symbol on the detected object, (iii) automatically generating a third control activation signal A3=1 indicative of a successful decoding operation, and producing decoded symbol character data representative of the detected and read bar code symbol. As shown in FIG. 19, the third control activation signal A3 is provided to the system control subsystem 88 for detection, analysis and programmed response. The system control subsystem 88 responds as described above in relation to FIG. 18, whereby the data is decoded and formatted and sent to the data transmission subsystem 85. Within the context of the hardware design shown in FIG. 19, the data transmission subsystem 85 during the data transmission state automatically transmits produced symbol character data to the bost system (to which the bar code reading device is connected) or to some other data storage and/or processing device, only when the system control subsystem 88 detects the following conditions: (1) generation of third control activation signal A3=1 within a predetermined time period, indicative that the bar code symbol has been read; and (ii) generation of data transmission control activation control signal A4=1 (e.g. produced from manually-actuatable switch 87A) within a predetermined time frame, indicative that the user desires the produced bar code symbol character data to be transmitted to the host system or intended device. Within the context of the hardware design shown in FIG. 19, the state-selection sensor 87B has two functions: (i) to automatically generate the fourth control activation signal A4=1 whenever the scanner housing has been placed on a countertop or like surface, so that the system is automatically induced into its automatic hands-free mode of operation; and (ii) to automatically generate the fourth control activation signal A4=0 whenever the scanner housing has been lifted off of a countertop or like surface, so that the system is automatically induced into its automatic hands-on mode of operation. In the automatic hands-free mode of operation, the state-selection sensor 87B effectively overrides the data transmission switch 87A. In the automatic hands-on mode of operation, the data transmission switch 87A effectively overrides the state-selection sensor 87B. Within the context of the hardware design shown in FIG. 19, the system control subsystem 88 performs the following primary functions: (i) automatically receiving control activation signals A1, A2, A3 and A4; (ii) automatically generating enable signals E1, E2, E3, and E4; and (iii) automatically controlling the operation of the other subsystems in accordance with a system control program carried out by the system control subsystem 88 during the various modes of system operation. FIGS. 20 and 21 illustrate an automatically-activated laser bar code scanning system which does not provide an object detection subsystem. This bar code scanning system is activated from the bar code presence detection state. The automatically-activated laser bar code scanning system concept is shown in related patent application Ser. No. 09/204,176 (the '176 application being commonly owned by Metrologic Instruments, Inc. and incorporated herein by reference). FIG. 20, shows a third hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. An automatically-activated bar code symbol scanning platform 100 pursuant to this third embodiment comprises a number of subsystems, namely: a laser-based bar code symbol detection subsystem 101; a laser-based bar code symbol reading subsystem 102; a data transmission subsystem 103; a state indication subsystem 104; a data transmission activation switch or control device 105A integrated with the scanner housing (not shown) in part or whole; a mode-selection sensor 105B integrated with the scanner housing in part or whole; and a system control subsystem 106 operably connected to the other subsystems described above. In general, the system 100 has a number of preprogrammed states of operation, namely: an object detection state; a bar code symbol detection state; a bar code symbol reading state; and a data transmission state. Within the context of the system design shown in FIG. 20, the laser-based bar code symbol detection subsystem 101 performs the following primary functions during the bar code symbol detection state: (i) automatically generates a pulsed visible laser scanning pattern of predetermined characteristics within a laser-based bar code symbol detection field 107, defined relative to the scanner housing, to enable the detection of a bar code symbol on an object located in the field 107; (ii) automatically processes scan data collected from the bar code symbol detection field 107 and detects the presence of the bar code symbol thereon; and (iii) automatically generates a control activation signal A2=1 indicative thereof in response to the automatic detection of the bar code symbol. As shown in FIG. 20, the second control activation signal A2 is provided to the system control subsystem 106 for detection, analysis and programmed response. When second control activation signal A2 is provided to the system control subsystem 88, this causes the bar code symbol reading device to undergo a state transition from bar code symbol detection state to bar code symbol reading state. This transition has been previously described in detail in connection with FIG. 18 above. Within the context of the system design shown in FIG. 20, the laser-based bar code symbol reading subsystem 102 performs the following functions during the bar code symbol reading state: (i) automatically generates a visible laser scanning pattern of predetermined characteristics within a laser-based bar code (symbol) reading field 108 defined relative to the scanner housing, to enable scanning of the detected bar code symbol therein; (ii) automatically decode-processes scan data collected from the bar code symbol reading field 108 so as to detect the bar code symbol on the detected object; (iii) automatically generates a third control activation signal A3=1 indicative of a successful decoding operation, and produces decoded symbol character data representative of the detected and read bar code symbol. As shown in FIG. 20, the third control activation signal A3 is provided to the system control subsystem 106 for detection, analysis and programmed response. The system control subsystem 106 responds as described above in relation to FIG. 18, whereby the data is decoded and formatted and sent to the data transmission subsystem 103. Within the context of the system design shown in FIG. 20, the data transmission subsystem 103 during the Data Transmission State automatically transmits produced symbol character data to the host system (to which the bar code reading device is connected) or to some other data storage and/or processing device, only when the system control subsystem 106 detects the following conditions: (1) generation of third control activation signal A3=1 within a predetermined time period, indicative that the bar code symbol has been read; and (ii) generation of data transmission control activation signal A4=1 (e.g. produced from manually-actuatable switch 105A) within a predetermined time frame, indicative that user desires the produced bar code symbol character data to be transmitted to the host system or intended device. Within the context of the system design shown in FIG. 20, the state-selection sensor 105B has two primary functions: (i) to automatically generate the fourth control activation signal A4=1 whenever the scanner housing has been placed on a countertop or like surface so that the system is automatically induced into an automatic hands-free mode of operation; and (ii) to automatically generate the fourth control activation signal A4=0 whenever the scanner housing has been lifted off of a countertop or like surface so that the system is automatically induced into an automatic hands-on mode of operation. In the automatic hands-free mode of operation, the mode-select sensor 105B effectively overrides the data transmission switch 105A. In the automatic hands-on mode of operation, the data transmission switch 105A effectively overrides the mode-select sensor 105B. Within the context of the system design shown in FIG. 20, the system control subsystem 106 performs the following primary functions: (i) automatically receiving control activation signals A2, A3 and A4; (ii) automatically generating enable signals E2, E3, and E4; and (iii) automatically controlling the operation of the other subsystems in accordance with a system control program carried out by the system control subsystem 106 during the various modes of system operation. FIG. 21 is an electrical block diagram showing a fourth hardware embodiment for implementing an omnidirectional laser scanning platform mountable in the housing of the bar code scanners of FIG. 1 and/or FIG. 5. This fourth embodiment includes a number of subsystems, namely: a laser-based bar code symbol detection subsystem 131; a laser-based bar code symbol reading subsystem 132; a data transmission subsystem 133; a state indication subsystem 134; and a system control subsystem 136 operably connected to the other subsystems described above. In general, the system 130 has a number of preprogrammed states of operation, namely: a bar code symbol detection state; a bar code symbol reading state; and a data transmission state. Within the context of the system design shown in FIG. 21, the laser-based bar code symbol detection subsystem 131 performs the following primary functions during the bar code symbol detection state: (i) automatically generates a pulsed visible laser scanning pattern of predetermined characteristics within a laser-based bar code symbol detection field 137, defined relative to the scanner housing, to enable the detection of a bar code symbol on an object located in the field 137; (ii) automatically processes scan data collected from the bar code symbol detection field 137 and detects the presence of the bar code symbol thereon; and (iii) automatically generates a control activation signal A2=1 indicative thereof in response to the automatic detection of the bar code symbol. As shown in FIG. 21, the second control activation signal A2 is provided to the system control subsystem 136 for detection, analysis and programmed response. When second control activation signal A2 is provided to the system control subsystem 136, this causes the bar code symbol reading device to undergo a state transition from bar code symbol detection state to bar code symbol reading state. This transition has been described in detail in connection with FIG. 18 above. Within the context of the system design shown in FIG. 21, the laser-based bar code symbol reading subsystem 132 performs the following functions during the bar code symbol reading state: (i) automatically generates a visible laser scanning pattern of predetermined characteristics within a laser-based bar code (symbol) reading field 138 defined relative to the scanner housing, to enable scanning of the detected bar code symbol therein; (ii) automatically decode-processes scan data collected from the bar code symbol reading field 138 so as to detect the bar code symbol on the detected object; (iii) automatically generates a third control activation signal A3=1 indicative of a successful decoding operation, and produces decoded symbol character data representative of the detected and read bar code symbol. As shown in FIG. 21, the third control activation signal A3 is provided to the system control subsystem 136 for detection, analysis and programmed response. The system control subsystem 136 responds as described above in relation to FIG. 18, whereby the data is decoded and formatted and sent to the data transmission subsystem 133. Within the context of the system design shown in FIG. 21, the data transmission subsystem 133 during the data transmission state automatically transmits produced symbol character data to the host system (to which the bar code reading device is connected) or to some other data storage and/or processing device, only when the system control subsystem 136 detects the generation of third control activation signal A3=1 within a predetermined time period, indicative that the bar code symbol has been read. Within the context of the system design shown in FIG. 21, the system control subsystem 136 performs the following primary functions: (i) automatically receiving control activation signals A2, A3 and A4; (ii) automatically generating enable signals E2, E3, and E4; and (iii) automatically controlling the operation of the other subsystems in accordance with a system control program carried out by the system control subsystem 106 during the various modes of system operation. Having set forth various preferred embodiments and certain modifications to the concepts underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with the underlying concepts. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims. While the particular illustrative embodiments shown and described above will be useful in many applications in code symbol reading, further modifications to the present invention herein disclosed will occur to persons with ordinary skill in the art. All such modifications are deemed to be within the scope and spirit of the present invention defined by the appended Claims to Invention.
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<SOH> BACKGROUND OF THE INVENTION <EOH>1. Field of the Invention The present invention relates generally to laser scanning systems, and more particularly to countertop bar code scanners that are equipped with adjustable mounting mechanisms and adapted to operate in an automatic “hands-free” mode of operation. 2. Description of Background Art Optical scanners of various types have been developed for scanning and decoding bar code symbols. These scanners adapt readily to some operational environments, but present shortcomings when used in other situations. For example, consider system applications involving point-of-sale (POS) terminals in retail stores and supermarkets, inventory and document tracking, and diverse data control applications. Retail point-of-sale counters are prime sales areas Display designs and product offerings may change on a regular basis. Inventory and document tracking involves scanning a number of items or documents of widely varying shapes and sizes. Diverse data control applications may involve managing data flow on a factory assembly line where a variety of components and processes must be tracked. These applications demand a bar code scanner that presents some degree of mechanical flexibility for use in any of a wide range of operational environments. Many existing bar code scanner designs are inadequately equipped to deal with the mechanical strains and stresses of day-to-day use. In many point-of-sale and factory environments, scanners are dropped, banged, and bumped. Delicate optical components may be damaged or misaligned, causing the performance of the scanner to degrade over time. Unfortunately, virtually all existing scanners are fabricated of high-impact polystyrene plastic, which provides only limited protection against mechanical shocks and bumps. In addition to lacking mechanical ruggedness, bar code scanners suffer from other deficiencies. Existing canners generally fall into one of two general categories: hand-held or stationary. The first category includes manually-actuated trigger-operated scanners, as well as automatically actuated hand-held scanners which do not utilize a triggering mechanism. The user positions the hand-held laser scanner at a specified distance from the object bearing the bar code. In the case of an automatically actuated scanner, the presence of the object is automatically detected, the presence of a bar code symbol on the object is detected, and thereafter the bar code symbol is automatically read. In the case of trigger-operated scanners, the user positions the scanner at a specified distance from an object bearing a bar code symbol, manually activates the scanner to initiate reading and then moves the scanner over other objects bearing symbols to be read. Prior art trigger-operated bar code readers are disclosed in U.S. Pat. Nos. 4,387,297 to Swartz; U.S. Pat. No. 4,575,625 to Knowles; U.S. Pat. No. 4,845,349 to Cherry; U.S. Pat. No. 4,825,057 to Swartz, et al.; U.S. Pat. No. 4,903,848 to Knowles; U.S. Pat. No. 5,107,100 to Shepard, et al.; U.S. Pat. No. 5,080,456 to Katz, et al.; and U.S. Pat. No. 5,047,617 to Shepard, et al. Automatic laser-based bar code symbol reading systems are disclosed in U.S. Pat. No. 4,639,606 to Boles, et al., and U.S. Pat. No. 4,933,538 to Heiman, et al. Several hand-held scanners have been developed to provide “omnidirectional” scanning, so as to permit reading of a bar code irrespective of its specific orientation within the scanning pattern. Examples of such systems include the NCR 7890 presentation scanner from the NCR Corporation and the LS9100 omnidirectional laser scanner from Symbol Technologies, Inc. Although these systems provide both hands-free as well as hands-on modes of operation, each of these systems suffers from a number of shortcomings. In particular, the spatial extent of the scan pattern produced from these scanners frequently results in the inadvertent scanning of code symbols on products placed near the scanner during its hands-free mode of operation. On the the other hand, in the hands-on mode of operation, it is virtually impossible to use these scanners to read bar code symbol menus provided in diverse application environments. In each of these scanner designs, the scanner is tethered to its base unit by a power/signal cord, and the user is required to handle the scanner housing in an awkward manner in the hands-on mode of operation, resulting in strain and fatigue and thus a decrease in productivity. In addition, the control structure provided in each of these hand-held projection scanners operates the scanner components in a manner which involves inefficient consumption of electrical power, and prevents diverse modes of automatic code symbol reading which would be desired in many portable scanning environments. Hand-held scanners are not convenient to use in assembly-line applications where the user processes bar coded objects over an extended period of time, or where the user requires the use of both hands in order to manipulate objects. In other applications, hand-held scanners are difficult to manipulate while simultaneously moving objects or performing other tasks at a point-of-sale terminal. Stationary scanners, on the other hand, provide a degree of flexibility in many applications by allowing the user to manipulate bar coded objects with both hands. However, by their nature, stationary laser scanners render scanning large, heavy objects a difficult task, as such objects must be manually moved into or through the laser scan field. One type of stationary scanner is frequently mounted within a checkout counter of a supermarket or other retail point-of-sale environment. Such “in-counter” or “presentation” scanners could also be employed in conjunction with conveyors at a factory assembly line. These scanning systems include a scanning window or aperture at the top of the scanner housing through which a scanning pattern is projected. The scanning pattern is typically provided in the form of a plurality of multi-directional scanning lines. When an item bearing a bar code is brought into the field of the scan pattern so that at least one of the scanning lines completely traverses the bar code, light is reflected from the bar code and received back through the window. Stationary in-counter and presentation scanners use a variety of optical configurations to develop omnidirectional scanning patterns. These omnidirectional patterns are intended to ensure that at least one scanning line will cross a bar code symbol to be read, irrespective of the bar code's orientation within the scanning pattern. Examples of omnidirectional scanning patterns include comb patterns, orthogonal patterns, interlaced patterns, star-like patterns, lissajous patterns, and the like. While such scanners may be suitable for certain applications, the physical configuration of the optical components necessary to produce such complex omnidirectional patterns has resulted in scanner housings which are quite large and bulky. Moreover, the window of a counter-top or presentation scanner generally faces in a single, fixed direction. To change the direction of the scanning window and, thus, the orientation of the scanning pattern, it is necessary to relocate the entire housing. In many applications, this is inconvenient, especially when there is limited counter space. One example of a stationary scanner, disclosed in U.S. Pat. No. 4,713,532, produces a scanning pattern having three groups of intersecting lines. These line groups form a large “sweet spot” which permits substantially omnidirectional reading of bar codes. The '532 scanner has a compact housing with a relatively small footprint, and is mountable on or in a counter. Depending upon the orientation of the window, the scanning pattern may be projected horizontally, vertically, or at an angle. An example of a scanner constructed in accordance with the '532 patent is the MS260 scanner, available from Metrologic Instruments of Blackwood, N.J. However, once the scanner was mounted in a given orientation, it was fixed and could not be easily moved. Another example of a stationary scanner is disclosed in U.S. Pat. No. 5,216,231. This scanner is mountable on an adjustable base positioned above a counter. The base is constructed to permit the scanner housing to be adjusted in any of a variety of directions so that the scanning pattern will be projected at a desired orientation with respect to the counter. However, the base must be permanently secured to the countertop, which prevents the scanner from being lifted by hand to scan large or bulky items which do not fit on the countertop. An attempt to combine the advantages of a hand-held scanner and a stationary scanner, U.S. Pat. No. 5,767,501 describes a hand-held scanner mounted in the head of a hand-supportable housing. The housing can also be supported in a separate base for hands-free presentation or countertop scanning. The base unit is mountable to a counter, and is equipped with a pivoting receptacle. The pivoting receptacle permits the scanning window and, hence, the scanning pattern, to be adjustable about a horizontal axis. Unfortunately, the user must return the hand-supportable housing to the base unit after each scan, requiring a realignment of the handle and handle receiving portions. This realignment process becomes tedious and annoying with repeated use. Moreover, the base unit is large and cumbersome for use in many point-of-sale environments. Another attempt to combine the advantages of a hand-held scanner and a stationary scanner, U.S. Pat. No. 4,766,297 discloses a bar code scanning system which can be used in either a hands-on or hands-free mode of operation. The scanning system includes a portable hand-held laser scanning device for generating electrical signals corresponding to a scanned bar code symbol. In the hands-on mode of operation, a trigger is manually actuated each time the scanner operator wishes to read a bar code symbol on an object. The system also includes a fixture having a head portion for receiving and supporting the hand-held scanner, and a base portion above which the head portion is supported at a predetermined distance. In the hands-free mode of operation, the scanner is supported by the fixture head portion above the fixture base portion in order to allow objects bearing bar code symbols to pass between the head and base portions. In order to detect the presence of an object between the head and base portions, the fixture also includes an object sensor operably coupled to the scanner. When the object sensor senses an object between the head portion and the base portion, the sensor automatically causes the scanner, while supported in the fixture, to read the bar code symbol on the detected object. Whereas bar code symbol scanning systems of the type disclosed in U.S. Pat. No. 4,776,297 permit reading of printed bar code information using either a portable (hands-on), or stationary (hands-free) mode of operation, such systems suffers from several significant drawbacks. For example, assume that it is desired to scan a large, heavy object such as an 80-lb. bag of concrete. The scanner operator could use the scanner in the hands-on mode of operation, but they would need to manually actuate a trigger each time the bar code symbol is to be read. If the scanner operator needs to move the bag into position, this is a two-handed job in itself, and the task of manipulating a trigger on the scanner during this positioning process is cumbersome and tedious at best. On the other hand, in the hands-free mode of operation, the heavy bag must be passed between the head and base portions of the fixture. If the bag will not fit between the head and the base portions, then one must resort to triggered operation. Another scanning configuration is disclosed in U.S. Pat. No. 5,479,002. A scan head is adjustably mounted in a ball-and-socket joint on a scan module or housing. The scan head is movable about three mutually orthogonal axes, so as to allow the operator to steer the light beam emitted from the head. However, the '002 patent does not disclose or suggest any technique for combining the scan head and lower housing into a single package that is conveniently hand-held, but that can also be used as a free-standing scanner. Moreover, the design of the '002 housing is directed to a single-line scanning pattern and would not lend itself to production of an omnidirectional scanning pattern. Additional attempts to produce omnidirectional scanners having adjustable housings or bases include the Model LS9100 Scanner, available from Symbol Technologies, and the Duet Scanner, available from PSC. Unfortunately, both of these scanners require the user to remove the hand-held scanner from a stand for hand-supported scanning. Thus, there is a great need in the bar code symbol reading art for a bar code symbol reading system which overcomes the above described shortcomings and drawbacks of prior art devices and techniques, while providing greater versatility in its use. A need remains for a scanner configuration that is adjustable about one or more axes with respect to the base, but that does not entail the inconvenience of a separate scanner and stand. This configuration would permit omnidirectional bar code scanning from a hands-free standing position on a countertop or work surface, as well as from a hand-supported position for scanning large, heavy, or bulky items without requiring the scanner operator to repeatedly remove and/or replace the scanner in its stand.
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<SOH> OBJECTS AND SUMMARY OF THE INVENTION <EOH>It is an object of the invention to provide a bar code scanner that is mechanically rugged, so as to endure environmental shock and applied mechanical stresses such as drops and bumps. It is a further object of the invention to provide a self-standing bar code scanner that need not be permanently mounted to a work surface. It is a still further object of the invention to provide a bar code scanner which occupies a relatively small footprint on a work surface. It is another object of the present invention to provide a bar code scanner that can operate in a hands-free mode, and can also be picked up with a single hand. It is a further object of the invention to provide a bar code scanner with an omnidirectional scanning pattern so as to permit reading of bar codes presented to the scanner. It is a still further object of the invention to provide a bar code scanner with an omnidirectional scanning pattern so as to permit reading of bar codes that are passed through the scanning pattern. It is another object of the invention to provide an automatic bar code symbol reading system having an automatic hand-supportable laser scanning device which can be used at a point-of-sale (POS) station as either a portable hand-supported laser scanner when operated in its automatic hands-on mode of operation, or as a stationary laser projection scanner when operated in its automatic hands-free mode of operation. It is another object of the present invention to provide such an automatic bar code symbol reading system, wherein a highly collimated laser scanning pattern is projected about a projection axis, and comprises scanning planes which intersect within a confined scanning volume extending about the projection axis so that bar code symbols disposed within the scanning volume can be read omnidirectionally, while inadvertent scanning of bar code symbols outside of the scanning volume is prevented. It is another object of the present invention to provide such an automatic bar code symbol reading system, wherein the confined scanning volume is substantially symmetrically disposed about an axis perpendicular to the plane of the scanner window. Another object of the present invention to provide an automatic hand-supportable omnidirectional scanner with a hand-supportable housing that allows to user to easily control the direction of its projection axis by way of the outer casing of the housing, and thus align the narrowly confined scanning volume; of the scanner with the bar code symbol on the object to be scanned and identified. Another object of the present invention to provide a portable automatic hand-supportable omnidirectional laser projection scanner with a power-conserving control system that provides battery power to the system components of the scanner in an intelligent manner. Another object of the present invention to provide an automatic hand-supportable omnidirectional scanner with a housing that visually, indicates the direction of the projection axis, for intuitive hand-supported omnidirectional scanning of bar code symbols within the confined scanning volume extending thereabout. It is another object of the present invention to provide such an automatic bar code symbol reading system, in which one or more bar code symbols on an object can be automatically read in a consecutive manner. A further object is to provide such an automatic bar code symbol reading device, in which the hand-supportable bar code scanner has an infrared light object detection field which spatially encompasses at least a portion of its volumetric scanning field along the operative scanning range of the device, thereby improving the laser beam pointing efficiency of the device during the automatic bar code reading process. Another object of the present invention is to provide an automatic bar code symbol reading system, in which battery power from a supply within the housing is automatically metered out and provided to the power distribution circuitry thereof for a predetermined time period which is reset upon the occurrence of either the manual actuation of an externally mounted power reset button, the reading (i.e. scanning and decoding) of a valid bar code symbol, or the placement of the hand-supportable bar code symbol reading device on a work surface and/or counter top. A further object of the present invention is to provide such an automatic bar code symbol reading device, with a novel automatic power control circuit that effectively conserves the consumption of battery power therein, without compromising the operation, or performance of the device during its diverse modes of automatic operation. It is another object of the present invention is to provide an automatic hand-supportable bar code reading device having both long and short-range modes of bar code symbol reading, automatically selectable in a variety of different ways, (e.g. by placing the hand-supportable device on a countertop or work surface, or removing it therefrom). Another object of the present invention is to provide such a multi-mode automatic bar code symbol reading device, so that it can: be used in various bar code symbol reading applications, such as, for example, charge coupled device (CCD) scanner emulation, counter-top projection scanning in the hands-free long-range mode of operation, or the like. Another object of the present invention is to provide an automatic hand-supportable bar code reading device with a programmably selectable mode of operation that prevents multiple reading of the same bar code symbol due to dwelling of the laser scanning beam upon a bar code symbol for an extended period of time, yet allows a plurality of bar code symbols (e.g. representing the same UPC) to be read in a consecutive manner even though they are printed on the same, or apparently the same, object or surface, as often is the case in inventory scanning applications. A further object of the present invention is to provide a point-of-sale station (POS) incorporating the automatic bar code symbol reading system of the present invention. It is a further object of the present invention is to provide an automatic hand-supportable bar code reading device having a control system which has a finite number of states through which the device may pass during its automatic operation, in response to diverse conditions automatically detected within the object detection and scanning fields of the device. Another object of the present invention is to provide a portable, automatic bar code symbol reading device, wherein the laser beam scanning motor is operated at a lower angular velocity during its object detection state to conserve battery power consumption and facilitate rapid steady-state response when the device is induced into its bar code symbol detection and bar code symbol reading states of operation. Another object of the present invention is to provide a portable automatic bar code symbol reading device, wherein the laser beam scanning motor is denergized during its object detection state to conserve battery power consumption, and is momentarily overdriven to facilitate rapid steady-state response when the device undergoes a transition from the object detection state to the bar code symbol detection state of operation. Another object of the present invention is to provide a novel mechanism for mounting a projection laser scanning platform within the housing of an automatic hand-supportable omnidirectional projection laser scanner. Another object of the present invention is to provide a novel omnidirectional laser scanning platform for use within an automatic portable projection laser scanner. Another object of the present invention is to provide a bar code symbol reading system having at least one hand-supportable bar code symbol reading device which, after each successful reading of a code symbol, automatically synthesizes and then transmits a data packet to a base unit positioned within the data transmission range of the bar code symbol reading device, and upon the successful receipt of the transmitted data packet and recovery of symbol character data therefrom, the base unit transmits an acoustical acknowledgement signal that is perceptible to the user of the bar code symbol reading device residing within the data transmission range thereof. A further object of the present invention is to provide such a system with one or more automatic (i.e., triggerless) hand-supportable laser-based bar code symbol reading devices, each of which is capable of automatically transmitting data packets to its base unit after each successful reading of a bar code symbol. A further object of the present invention is to provide such a bar code symbol reading system in which the hand-supportable bar code symbol reading device can be used as either a portable hand-supported laser scanner in an automatic hands-on mode of operation, or as a stationary laser projection scanner in an automatic hands-free mode of operation. A further object of the present invention is to provide such a bar code symbol system in which the base unit contains a battery recharging device that automatically recharges batteries contained in the hand-supportable device when the hand-supportable device is supported within the base unit. It is another object of the present invention to provide such an automatic bar code symbol reading system with a mode of operation that permits the user to automatically read one or more bar code symbols on an object in a consecutive manner. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which a plurality of automatic hand-supportable bar code symbol reading devices are used in conjunction with a plurality of base units, each of which is assigned to a particular bar code symbol reading device. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which radio frequency (RF) carrier signals are used by each hand-supportable bar code symbol reading device to transmit data packets to respective base units. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which a novel data packet transmission and reception scheme is used to minimize the occurrence of data packet interference at each base unit during data packet reception. A further object of the present invention is to provide such an automatic bar code symbol reading system, in which the novel data packet transmission and reception scheme enables each base unit to distinguish data packets associated with consecutively different bar code symbols read by a particular bar code symbol reading device, without the transmission of electromagnetic-based data packet acknowledgment signals after receiving each data packet at the base unit. It is a further object of the present invention to provide an automatic hand-supportable bar code reading device having a control system which has a finite number of states through which the device may pass during its automatic operation, in response to diverse conditions automatically detected within the object detection and scan fields of the device. It is yet a further object of the present invention to provide a portable, fully automatic bar code symbol reading system which is compact, simple to use and versatile. Yet a further object of the present invention is to provider a novel method of reading bar code symbols using an automatic hand-supportable omnidirectional laser scanning device. These and other objects of the present invention are realized in the form of an improved counter-top bar code scanner that is equipped with a bump protection mechanism and a scan angle adjustment mechanism. The bump protection mechanism is provided in the form of a protective sheath fabricated of a shock-absorbing material. The scan angle adjustment mechanism is provided in the form of a movable bracket adjustably mounted to the scanner housing. The bracket permits adjustment of the housing relative to the bracket. For example, if the bracket is mounted to a fixed surface, the bracket remains fixed but permits adjustments of the housing to any of a plurality of positions relative to the fixed surface. According to one preferred embodiment of the invention, the movable bracket permits adjustment of the housing to at least any of the two positions along an axis of rotation. In this manner, the coverage area of the scanning pattern may be adjusted and/or resituated. When the movable bracket is rested upon a work surface or countertop, the scanner operates in an automatic, hands-free mode. When the scanner and movable bracket are lifted from the work surface or countertop, the scanner operates in an automatic, hand-held mode. The scanning pattern permits reading of bar codes presented to the scanner, as well as bar codes that are passed through the scanning pattern. Taken together, the bar code scanner housing and bracket provide a self-standing bar code scanner that need not be permanently mounted to a work surface. Pursuant to a further embodiment of the invention, the shock-absorbing encasement is removable to permit cleaning and/or replacement of the material, and/or to permit servicing of the bar code scanner. In this manner, the invention provides a rugged bar code symbol reading system having an automatic hand-supportable scanning device which can be used at a point-of-sale (POS) station as either a portable hand-supported laser scanner, or as a stationary laser projection scanner. This configuration permits omnidirectional bar code scanning from a hands-free standing position on a countertop or work surface, as well as from a hand-supported position for scanning large, heavy, or bulky items without requiring the scanner operator to remove and/or replace a scanner in a stand.
|
20040707
|
20060404
|
20050224
|
61839.0
| 0
|
CAPUTO, LISA M
|
COUNTER-TOP SCANNER WITH BUMP PROTECTION MECHANISM AND SCAN ANGLE ADJUSTMENT MECHANISM
|
UNDISCOUNTED
| 1
|
CONT-ACCEPTED
| 2,004
|
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