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A window blind is a type of window covering . [ 1 ] There are many different kinds of window blinds which use a variety of control systems. A typical window blind is made up of several long horizontal or vertical slats of various types of hard material, including wood, plastic or metal which are held together by cords that run through the blind slats. Vertical blinds run along a track system which can tilt open and closed and move side-to-side. Window blinds can be manoeuvred with either a manual or remote control by rotating them from an open position, with slats spaced out, to a closed position where slats overlap and block out most of the light. There are also several types of window coverings, called shades, that use a single piece of soft material instead of slats. The term window blinds can also be used to describe window coverings more broadly. In this context window blinds include almost every type of window covering, whether it is a hard or soft material; i.e. shutters, roller shades, cellular shades (also called honeycomb shades), wood blinds, Roman shades, standard vertical, and horizontal blinds (also called Venetians). In the United Kingdom , awnings are sometimes called blinds or shades. Window blinds are generally sold as either ready-made or made to measure . As the names suggest, blinds that are ready-made are manufactured to set sizes based on typical window dimensions, whereas blinds that are made to a measurement are cut to a specific width and drop to match the window. The advantage of ready-made blinds is their availability and cost, whereas blinds that are made to measure will be more expensive but better fit the dimensions of a window. Aside from coming in different dimensions, window blinds can also come in a variety of different styles, materials, colours and patterns. Below is a list of several popular styles of blinds: Window blinds can be drawn manually using a cord, or automated through motorization. Controls for motorized blinds can be from a wall switch or keypad, remote control, or computer, eliminating the need for cords and allowing control of otherwise inaccessible windows. A number of modern homes are integrating blind control with central C-Bus solutions. This control provides ease of use and is effective for controlling blind operation to reduce heat loss during winter or minimize heat from the sun during summer. [ citation needed ] Panel blinds, sometimes referred to as Japanese blinds as they are based on Japanese shōji , are thin blinds in a panel shape that run along a track. Almost any fabric or paper can be employed, although 90% of all shoji blinds use white polyester to imitate ' washi ' Japanese paper. [ clarification needed ] Cellular shades or cellular blinds, sometimes referred to as honeycomb shades, are a type of window blind made of a long and continuous fabric with a cellular structure when opened and fold onto themselves when closed. The honeycomb shades were introduced in 1985. [ 2 ] The fabric is often made from soft paper or cloth-like material and is available in a variety of different structures including single cell, double cell or triple cell. Cellular blinds work by trapping air inside the cell structure once opened and create a barrier between the window surface and the room. Due to the unavailability of standardized tests, no ranking system currently exists to compare the efficacy of these blinds. Windows and doors make up for almost one-third of a home's total thermal loss, according to the Department of Energy (United Kingdom) . [ 3 ] This applies to heat loss in winter as well as entry of undesired heat in summer. When air inside the room comes in contact with windows, it is cooled or warmed. By convection , this air then circulates around the room. Cell shapes in the blinds hold trapped air and create a barrier between the window surface and the room, thus lessening the transfer of heat. Shades, however, provide only slight control of air infiltration. [ 4 ] In common with all blinds, cellular shades can reduce solar gain in summer and provide room darkening or blackout for sleeping. Like most other window treatments, they are raised and lowered with a string. Cordless cellular shades are available to reduce the risk of strangulation for small children. [ 5 ] One may also have the option of lowering the top of the shade down, and/or the bottom of the shade up; commonly referred to as a Top-Down-Bottom-Up mechanism. Roman shades are a type of window blind used to help block out the sun. Although often called blinds, these are actually referred to as "shades" in the window covering industry. They are often referred to as Romans or Roman blinds in the UK . When opened, the Romans stack up evenly; when covering the full window height, they are smooth without overlapping. Roman blinds can be purchased with a blackout lining on the back to fully block out sunlight. However, there will always be small light gaps on the edges of the blinds if mounted on the inside of the window frame or peeking out from behind the blind if mounted on the frame around the window. Unlike other blinds, such as certain fabrics used for roller shades, vinyl vertical blinds, or vinyl horizontal blinds, Roman shades are not an ideal option for areas with a lot of moisture, such as bathrooms or windows above a kitchen sink. Roller blinds are a type of window blind that is typically made from a polyester fabric wrapped around a plastic or metal roller. The roller may either be exposed or enclosed inside of a frame and can be placed at the top of the window recess or outside of the recess. To control the roller blind there is typically a chain or string on either side of the blind. When the side chain is pulled one direction the roller will raise, and if pulled in the opposite direction it will lower instead. Some manufacturers also produce a version of roller blinds with two layers of fabric, sometimes referred to as double roller blinds, for even greater control of light filtration through a window. Typically, one layer will be made of a sheer fabric that can be used to reduce glare, with a second layer that typically includes a blackout lining for even greater filtration when necessary. A Venetian blind is a type of window blind made from overlapping horizontal slats that are typically lowered and drawn together by pulling a cord. [ 6 ] The slats are typically manufactured using a rigid material such as aluminium, plastic, or wood and move in unison through a series of wires that run through the blinds. In the late 19th and early 20th centuries, Venetian blinds were widely adopted in office buildings to regulate light and air. A large modern complex in the US that adopted Venetian blinds was Rockefeller Center's RCA Building (better known as the Radio City building) in New York City , completed in the 1930s. One of the largest orders for Venetian blinds ever placed was to the Burlington Venetian Blind Co., of Burlington, Vermont , which supplied blinds for the windows of the Empire State Building in New York City. [ 7 ] [ 8 ] In 1994, a design for Venetian blinds integrated with window glass panels was patented. [ 9 ] This new type of blind overcomes the problems related to damaging and fouling. Usually, magnets are used for motor transmission in order to preserve the sealing inside the insulating glass. [ citation needed ] Vertical blinds were introduced in 1948 (Flexible Blind Company, Hunter Douglas [ 10 ] ), and gained acceptance as an alternative to draperies due to the streamlined look, versatility, energy efficiency, large variety of finishes. [ 11 ] The construction includes a horizontal (occasionally, in custom designs, tilted) track with moving carriers and vertical strips, called vanes , hanging off the carriers [ 12 ] (attached by clips ). The vanes can rotate, changing the amount of light entering the room, and, when in open position, traverse the track (and thus be stacked compactly on one side of the window). When closed, the vanes tightly overlap, creating a good barrier against the sunlight penetration in summer and energy loss in winter. [ 11 ] Unlike horizontal blinds, vertical blinds are less likely to collect dust because they stand vertically. Since they draw to the side rather than lifting and lowering, they are easier and faster to operate. They operate best on patio doors and sliding windows that slide from side to side. In the 1970s there were few choices of fabric- usually beige or white, which had to have stiffener embedded to prevent fraying, rather like on roller blinds fabric but using a thicker textile. Vertical blinds became available in flat plastic (PVC), fabric, embossed PVC, also S-curved slats. A more modern modification is to offer them with wood trim at the top and bottom—sometimes midway as well—and these are usually described as "Japanese Vertical blinds" because they are often coordinated with Japanese style Shoji blinds using the same timber. Vertical blinds were most popular in the UK during the 1990s, since then sales have slowed as they lost popularity with a younger generation. Stationary vertical blinds are hung in the doorways of some homes and businesses which generally leave the door open. Movement of the blind may signal a change in airflow, or someone entering the doorway. More commonly, however, these vertical blinds are made of thick plastic. In the cold rooms of food businesses, this slows the heat leakage into the cold room. In warmer climates, vertical blinds discourage flies and some other insects from entering the building. In certain areas of the UK window blinds are used to disguise the fact that offices have PCs in them and are used as a burglary deterrent. Other varieties of window blinds include mini blinds (typically aluminum, Venetian-Style blinds with very narrow slats, usually 25 mm or 1 inch wide), micro blinds (usually 13 mm or 1 ⁄ 2 inch wide), louvers , jalousies , brise soleil and pleated blinds . Blinds can be made in a variety of materials; some expensive and some less so. Less expensive blinds are usually made in polyester, aluminum, or PVC. These are inexpensive materials that are all easily accessible and yet durable at the same time. A window blind is a means of screening a window, achieving similar results to those obtained by fitting curtains. Blinds are typically the same width and height as the window itself or slightly wider and taller—depending on whether they are fixed inside (Recess) or outside (Facefix) the window's reveal (i.e. the wall recess within which the window itself is fixed). Window blinds have varying thermal effects: they can block unwanted heat of the summer sun and they can keep in heat in cold weather. But in both of these applications, they also reduce light to varying degrees, depending on the design. Many kinds of blinds attempt varying balances of privacy and shade. Blinds can be made of a number of different materials and manufactured in a number of different ways. This usually determines the name by which the blind is commonly known. Blinds (otherwise referred to as "shades") made of fabric can either be rolled up (on a tube; Roller shades), folded up (Roman shades) or pushed up in an accordion style (Pleated and Cellular shades). Many fabrics are used including cotton, polyester, wool, viscose and silk to create these shades. A silk cloth can be present or embroidery stitch, which will give tissue varied terrain. Wooden blinds are generally known as Venetian blinds. A number of horizontal wooden slats are joined by corded pulleys which can either gather all the slats at the top of the window to reveal the view or simply angle the slats while allowing some light to travel through the blind yet retaining some level of privacy. Wooden blinds come in a number of finishes (determined by the type of wood used, which ranges from painted to most types of solid oak varieties) and sizes (determined by the width of each slat which is usually available in one of three widths—25 mm [1 in], 35 mm [ 1 + 1 ⁄ 2 in], or 50 mm [2 in]). Wooden Venetian blinds are also available as vertical blinds. These are usually made up of wider slats and operate in virtually the same way as their horizontal counterparts (i.e. instead of drawing upwards to reveal the window, they draw to one side gathering in a vertical bunch). Pinoleum blinds are made up of small wooden twigs laid horizontally which are joined by vertical threading. The resulting weave is, as a result, only flexible vertically and can be drawn upwards once manufactured as a roller blind or in a similar fashion to a Venetian blind. Conservatory blinds are often made with Pinoleum. In Malaysia, an outdoor blind is sometimes called a "chik". The word was carried over from India by the British during the colonial times. Faux wood blinds are an alternative to real wood blinds. Faux wood is also known by the trade name Plaswood (a portmanteau of plastic & wood ). Made of a composite of man-made materials and natural wood particles, faux wood can be a less expensive choice than natural wood. These blinds have become more popular as the products have matured, becoming cheaper and more versatile at the same time offering more of a natural wood look. Current faux wood blinds are warp resistant, have UV ratings as high as 500 and come in colors that would be hard to find in natural wood blinds. Because of their resistance to warping, faux wood window blinds are suitable for areas with extreme temperature swings or high moisture, such as bathrooms and kitchens. Venetian blinds, both horizontal and vertical, are available in a number of man-made materials (either resembling wood or metal or simply plastic). These are better suited to areas where moisture or direct contact with water is likely to cause a problem, such as bathrooms and kitchens. These blinds are often available with micro slats (as small as 16 mm or 5 ⁄ 8 in or less). The result of smaller slats is that more have to be used to obscure the window completely. Conservatory blinds (i.e. ceiling fixed via a number of horizontal pulleys) are often made of man-made materials. Corded window blinds present a strangulation hazard to children, causing 184 deaths in the United States between 1996 and 2012. [ 13 ] Recalls of window covering products have not significantly reduced the number of deaths since 1980. Retrofit kits have been used since 1995 to "reduce" the strangulation hazard; however, children have strangled on retrofit kits since 1995. [ 14 ] The US CPSC recommends using cordless or cord-free window coverings where children live or visit. [ 15 ] For window coverings that use continuous-loop cord systems, like vertical blinds, a wall cord cleat can be used to anchor the cord tightly to the wall and prevent children from having access to the dangling cord loop. Window blinds slats are held together with cords that allow for tilting slats, raising or lowering, and these are potentially dangerous if loose. As an added precaution, cord stops should be installed correctly and adjusted to restrict the movement of inner lift cords. [ 16 ] Some vehicles include or are retrofitted with sun blinds for rear and rear side windows. See also car glass . These blinds are used to protect the vehicle and the passengers from direct sunlight. Car shades are another common way to protect the vehicle. The shades for the rear and front windows are designed to be unfolded and sit against the window. They can be made of plastic or cardboard. The shades that go on the side windows of a vehicle are usually attached using either suction cups or static cling. Solid fabric and slat car blinds have given way to cheaper and more flexible, folding, wire-framed "dark-stocking" synthetic blinds. These are used where the car owner has not dark-tinted the glass of the car windows enough, or during the day, by drivers or passengers seeking more privacy. Most commercial airliners feature window blinds in the passenger cabin. These blinds are generally made of plastic and are usually closed during cruises. In a first for the aviation industry, the Boeing 787 Dreamliner lacks window blinds – instead, the airliner features an advanced window dimming system that serves the same purpose.	https://en.wikipedia.org/wiki/Window_blind
In construction , capping or window capping ( window cladding , window wrapping ) refers to the application of aluminum or vinyl sheeting cut and formed with a brake to fit over the exterior, wood trim of a building. The aluminum is intended to make aging trim with peeling paint look better, reduce future paint maintenance, and provide a weather-proof layer to control the infiltration of water. [ 1 ] The capping application must direct water away from the original under-lying wood material and prevent infiltration of water into the structure. Cladding applied to exterior window and door casing (brick-moulding) and their associated parts is often referred to as window capping or window cladding . This sort of capping is typically applied in order to eliminate the need to re-paint wood window trim. The aluminum capping helps to prevent wood rot by protecting the wood from water and snow. However, capping will exacerbate wood rot if the moisture in the wood is coming from inside the building or the capping leaks. Good installation of capping allows for an outlet for water in the event of a leak. Caulking and sealant materials may be used to help prevent leaks but these products are not considered reliable in the long-term. A sill that has been clad should provide a "drip cap" or "drip-control" function. This will serve to direct water away from the wall surface directly underneath the sill. The leading edge of the sill must be the lowest point on the sill to ensure that water does not wick into the sill material. Window capping may provide a marginal increase in energy efficiency by decreasing the potential for drafts by providing an extra barrier between the exterior and the interior. The most common material used in residential window capping is factory painted aluminum. An alternative to factory painted aluminum is to use a vinyl coated aluminium material. Aluminum capping can be painted so long as the painter is highly skilled and knowledgeable in the field of metal painting. Capping can hide problems rather than fix them. Aluminum and vinyl are impermeable materials so the natural transfer of moisture through the wood trim will be trapped when it reaches the capping material. The quality of paint on some aluminum coil stock begins to chalk or fade in about five years so the claim of being maintenance free can be misleading.	https://en.wikipedia.org/wiki/Window_capping
A window of opportunity , also called a margin of opportunity or critical window , is a period of time during which some action can be taken that will achieve a desired outcome. Once this period is over, or the "window is closed", the specified outcome is no longer possible. [ 2 ] Windows of opportunity include: The timing and length of a critical window may be well known and predictable (as in planetary transits ) or more poorly understood (as in medical emergencies or climate change ). In some cases, there may be multiple windows during which a goal can be achieved, as in the case of space launch windows. In situations with very brief or unpredictable windows of opportunity, automation may be employed to take advantage of these windows, as in algorithmic trading [ 14 ] and time-domain astronomy . [ 15 ] Real-time computing systems can guarantee responses on the order of milliseconds or less. [ 16 ] In some time-critical situations, failure to act may entail an increasing cost over time, or a decreasing probability over time of achieving the desired outcome. In real-time computing systems, this may be represented by time-utility functions .	https://en.wikipedia.org/wiki/Window_of_opportunity
Window shutter hardware , usually made of iron , are hinges and latches that attach to the shutter and a window frame (and in some cases directly attached to stone or brick). The hinges hold the shutter to the structure and allow the shutter to open and close over the window. The latches secure the shutter in the closed (over the window) position. Tie-back hardware can be used to hold the shutter in the open position. Exterior shutters were vital elements of homes in the colonies. Raised panel shutters provided security against access from ground level. Exterior shutters also proved a first barrier against the elements. In cities, shutters provided privacy screens for the residents. [ citation needed ] Louvered upstairs shutters were often later additions to the home. This article describes the evolution of early exterior window shutter hardware , terms and terminology related to shutter hardware and blacksmithing, and American regional styles of installation. In its earliest forms, most hardware was simple and hand-made – usually of readily available materials such as wood or leather . A patch of leather spanning between the stile and jamb and fastened with wooden pegs served to hinge a door or shutter. Hand-carved wooden hinges and pintles , slide bolts and lift- latches were whittled from a variety of woods. The earliest examples of iron hardware were sponsored by the nobility . [ citation needed ] Iron itself was expensive and a valued resource for any kingdom and had many other more valuable uses in weaponry and tools . In the post-Renaissance period industrial advances provided more iron and the emerging merchant / tradesman classes had money to purchase hardware for their homes and warehouses. Examples of hardware excavated from the Jamestown and Plymouth colonies of the 17th century were very ornate in design – typical of that being produced in England at the time. [ citation needed ] In Colonial America , hardware was made in England and imported to the colonies. It was illegal for the colonials to produce manufactured goods. [ citation needed ] America sold iron and charcoal to the British, who used those raw materials and their resident labor force to produce hardware which was then sold back to the captive market in the colonies. Virtually all of the early hardware in New York , Philadelphia , Annapolis , Alexandria , Key West , or anyplace else where British ships could berth, was made in England. Away from the ports and cities where British authority was centered, many locally-made examples of early hardware can be found. Examples of German , French , and Dutch hardware remain in the inland river valleys – the homelands of the early settlers . English hardware, however, was the overwhelming standard in colonial America and set the pattern for all that evolved. [ citation needed ] Virtually all of the shutters in colonial times were hung with strap hinges – following the examples in Britain. Strap hinges were strong and secure. The frames of windows were hewn from a single heavy piece of wood into which a heavy pintle could be driven. The rails of the shutter were often six or eight inches high and provided room to position the strap hinge across most of the width of the shutter. The hinges were fastened to the shutters with rivets or nails driven through and clinched on the inside of the closed shutter. Locks of the period followed the form of the strap hinges. The rolled barrel was replaced by a pin of about 1 ⁄ 2 " in diameter and twice the length of the thickness of the shutter mounted perpendicular to the face of the lock. The lock would be nailed or riveted on the lock rail of one shutter with the pin positioned about two inches beyond the edge of the shutter. The opposite shutter would be drilled through with a hole to accept the pin protruding from the lock. To close and secure the shutter: from the inside close the shutter with the hole then close the shutter with the lock. The lock pin passes through the hole and the user drops a simple nail-like key into the hole in the lock pin. The shutter is virtually impregnable from the exterior. [ citation needed ] Tie-backs of the Colonial era were mostly of English origin and many were of the "Rattail" style. Variations are noted as different British manufacturers vied to produce a less expensive product. Inland, where local smiths were producing hardware on their own, a wide range of patterns have been noted. Around 1750, colonial raw materials poured into the British Isles, and factories began to appear. The earlier hardware with its chiseled and filed details fast gave way to less expensive, but equally functional hardware of similar but unadorned design. H and HL hinges are a good example of this transition. [ citation needed ] After the American Revolution machines were invented to make screws and to produce rolled iron in thin sheets. By about 1800 cheap screws were readily available. Cast iron technology had long been available – now machine-made screws allowed such hardware to be economically mounted. Butt type hinges can be seen during this "Federal" Period (1800–1830) – but they quickly fell from favor, probably because they were subject to breakage. [ citation needed ] A more obvious change in the shutter hardware was noted in shutter bolts. The common slide plate and keeper style of bolt started to appear. It was simpler to fabricate and operate than the earlier "strap style lock". This bolt relied on both the new cheap fasteners and the readily available plate iron. This bolt also relied on machines and "dies." This form of shutter bolt has been made continually ever since. [ citation needed ] Strap hinges continued to dominate in the marketplace for hanging shutters. Drive pintles started to be replaced by similar pintles cut off and mounted on a piece of thin plate material and again fastened with the new screws. This is the precursor of the "plate pintle". [ citation needed ] Changes in construction have been noted in the same period. Structures were built with openings into which pre-fabricated windows were installed. The earliest examples date from around 1810 and used a variation on the strap hinge. Instead of mounting the pintle to the surface of the structure, a new form was designed. This pintle was a flat plate of about two inches high and notched to one half of its height and formed to a female barrel. Holes were punched in the side of the pintle, and it was screwed directly to the side of the window before the window was installed on the structure. The strap hinges were modified to match the new pintles and the hinge was of the same width as the pintle and notched to one half of its height. A pin to mate with the female pintle was welded in the hinge. Examples of this type proved to be very durable and were in regular and widespread use through the 1870s. Often when the shutters were removed – usually in the 20th century – cast type pintles were hit with a hammer and broken off flush with the edge of the window. The shutters often found their way into the basements of the home to provide coal bins for newly installed central heat or were nailed up in the barn to partition off pig sties or calf pens. [ citation needed ] Cast iron tie-backs became much more popular during the Federal period – usually mounted on arms extending from the window sills. The "Federal Shell" was the dominant pattern in this period. The next major change in shutter hardware coincided with the American Civil War era. Heavy presses and punches were in use in factories around the country and a maturing rail transportation system opened inland areas for the products of the factories. Iron was the norm up until that time – steel had been expensive to produce. Hardware makers were quick to take advantage of this new material. They produced the first of the "butt" and "H" or "Parliament" style lift-off hinges. Quick and easy to produce and strong enough to hold heavy shutters, they found favor in the new construction of the period. Around 1880 the first examples of "New York" style hardware appeared. [ citation needed ] Plate steel elements were assembled by unskilled labor in sprawling factories. This hardware style evolved into the many imported forms seen today. It provided the ability to surface mount hinges and tie the wooden elements of the shutters together, and also allowed for smaller and less expensive window and shutter elements. About this time the first commercially produced "S" style tie-backs were seen – manufactured by Stanley Works in Connecticut. Historically an "S" is a very difficult form to forge. Stanley forged the first simple styles for commercial consumption but it wasn't until the 1930s that they started to stamp them. [ citation needed ] Battens – the horizontal elements on "board and batten" shutters. Strap hinges usually mount centered on the battens. This is the standard construction approach for most barn doors. Butt mounted – hinges that mortise into the sides of the hinges – only the barrel of the hinge is visible when the shutter is in the closed position. Casement – the wood surrounding the window upon which the pintle is typically mounted. Hinges – mate with the Pintles and are mounted on the shutter. Pintles – the "pins" on which hinges swing. The pintles are, by definition, mounted to the structure. Pintles are offered in various configurations to match different installation situations. Rails – with louvered or raised panel shutters, the rails are the horizontal elements of wood that frame the shutter. The width of the rails is an important consideration when choosing surface mounted hardware. Show hinges – hinges arranged to mount so as to be visible when the shutter is in the open position. Stiles – when a shutter is louvered or of the raised panel style, the stiles are the vertical elements of the frame. Knowing the width of the stiles allows positioning of the first fastener on strap hinges on their mid-line. Surface mounted – hinges that mount to the face of the shutter – strap hinges and the "New York Style" hinges are examples. The hinges are visible when the shutter is in the closed position. Offset – the total dimension that the shutter will travel outwards when moved from the closed to the open position. The offset is typically the distance from the face of the casement to the outermost surface of the structure. The offset is developed in shutter hardware by selection of a pintle made to "stand off" the casement a given distance – the shutter hinge has a sharp bend which moves the hinge barrel away from the face of the shutter at a distance to match the pintle standoff. When measuring offset, it is critical to allow for irregularities in construction. Because brick and stone openings are rarely plumb and or perfectly flat, it is typical to use the greatest dimension and allow about ½" cushion. If the offset is too small the shutters will not open fully. If the offset is too great, the shutter will function well but sit off of the wall. Standoff – The pintle standoff is the distance from the face of the casement to the mid-line of the pintle pin. The hinge standoff is the distance from the face of the shutter to the center-line of the hinge barrel. Adding the pintle standoff to the hinge standoff results in the total offset. Virtually all commercially available shutter hardware is provided with matching standoff on the hinge and pintle. This assumes that the face of the shutter will lie on the same plane as the casement with the shutter in the closed position. Hinge and pintle standoffs can be custom made to a user's situation. This eases installation and insures proper shutter function. Throw – This is the measure of the horizontal movement of the edge of the shutter as it swings from the open to the closed position and varies greatly between hinge styles. If too little throw, the open shutter will cover the window molding. Too much throw and too much brick or siding shows between the open shutter edge and the window frame. Proper throw insures that the shutter will comfortably "frame" the window – not obstruct or detract from window detail. The shutter is fitted to the dimensions of the masonry opening. The pintle is embedded or surface mounted to the structure itself. The pintle pin is positioned on the outside corner of the masonry. This approach can be seen on brick structures, especially post-civil war commercial multi-story buildings. Also common in the south of Europe, France, Italy, and Austria, it allows the shutter to sit almost fully parallel to the structure. [ citation needed ] The European structures are typically stucco coated, with a drive type pintle built diagonally into the masonry prior to stucco finish. A lag screw pintle can be substituted for the drive pintle. Brick structures can employ a similar embedded pintle, or a surface mounted pintle. Storm type strap hinges are typically in Europe. American examples are often tapered. [ 1 ] The shutter in the closed position fits within the window casement. This was the prevalent approach in the Colonies from New York and south. An advantage is the additional security because the shutters can not be lifted from the pintles in the closed position. A disadvantage is that the shutters must be matched closely to the inside dimension of the casing and the shutter rabbet should match the thickness of the shutters. Any surface mounted hinge and pintle can be used, assuming there is sufficient width to the casing to accept the pintle. The hinge has a minimal standoff and the pintle would have the same matching standoff. Together an offset of 1–1½ inches will hold the shutter at the same distance from the structure and not quite parallel to the wall. Historically, this approach was seen through the New England colonies. Virtually every old home is a clapboard structure fitted with shutters applied in this manner. They were likely hung on the casing to allow for the frost heaves and movement of the structures in the harsh New England winters. The shutters simply allowed the house to heave and settle behind them. A strap hinge with a zero offset and an angle pintle matched to the thickness of the shutter will serve in every case. The shutter is removed from the face of the casing by the thickness of the shutter plus the diameter of the pintle pin leaving the shutter to clear the corner of the casing. [ 2 ] This style is traditional to suburbs of Philadelphia, Pennsylvania, including Chester, Bucks, and Montgomery Counties. The amount of the required offset is divided evenly between the hinge and the pintle.	https://en.wikipedia.org/wiki/Window_shutter_hardware
Windows 9x is a generic term referring to a line of discontinued Microsoft Windows operating systems released from 1995 to 2000 and supported until 2006, which were based on the kernel introduced in Windows 95 and modified in succeeding versions, with its underlying foundation based on MS-DOS . [ 4 ] The first version in the 9x series was Windows 95, which was succeeded by Windows 98 and then Windows Me , which was the third and last version of Windows on the 9x line, until the series was superseded by Windows XP . [ 5 ] Windows 9x is predominantly known for its use in home desktops . In 1998, Windows made up 82% of operating system market share. [ 6 ] The internal release number for versions of Windows 9x is 4.x. The internal versions for Windows 95, 98, and Me are 4.0, 4.1, and 4.9, respectively. Previous MS-DOS-based versions of Windows used version numbers of 3.2 or lower . Windows NT , which was aimed at professional users such as networks and businesses, used a similar but separate version number between 3.1 and 4.0. All versions of Windows from Windows XP onwards are based on the Windows NT codebase. The first independent version of Microsoft Windows, version 1.0 , released on November 20, 1985, achieved little popularity. Its name was initially "Interface Manager", but Rowland Hanson , the head of marketing at Microsoft, convinced the company that the name Windows would be more appealing to consumers. Windows 1.0 was not a complete operating system, but rather an "operating environment" that extended MS-DOS . Consequently, it shared the inherent flaws and problems of MS-DOS. The second installment of Microsoft Windows, version 2.0 , was released on December 9, 1987, and used the real-mode memory model, which confined it to a maximum of 1 megabyte of memory. In such a configuration, it could run under another multitasking system like DESQview , which used the 286 Protected Mode . Microsoft Windows scored a significant success with Windows 3.0 , released in 1990. In addition to improved capabilities given to native applications, Windows also allowed users to better multitask older MS-DOS-based software compared to Windows/386 , thanks to the introduction of virtual memory . Microsoft developed Windows 3.1 , which included several improvements to Windows 3.0. It also excluded support for Real mode, and only ran on an Intel 80286 or better processor. Windows 3.1 was released on April 6, 1992. In November 1993 Microsoft also released Windows 3.11 , a touch-up to Windows 3.1 which included all of the patches and updates that followed the release of Windows 3.1 in early 1992. Meanwhile, Microsoft continued to develop Windows NT . The main architect of the system was Dave Cutler , one of the chief architects of VMS at Digital Equipment Corporation . [ 7 ] Microsoft hired him in August 1988 to create a successor to OS/2 , but Cutler created a completely new system instead based on his MICA project at Digital. [ 8 ] The first version of Windows NT, Windows NT 3.1 , would be released on July 27, 1993 and used Windows 3.1's interface. About a year before the development of Windows 3.1's successor (Windows 95, code-named Chicago) began, Microsoft announced at its 1991 Professional Developers Conference that they would be developing a successor to Windows NT code-named Cairo , [ 9 ] which some viewed it as succeeding both Windows NT and Windows 3.1's successor under one unified system. [ 10 ] Microsoft publicly demonstrated Cairo at the 1993 Professional Developers Conference, complete with a demo system running Cairo for all attendees to use. Based on the Windows NT kernel, Cairo was a next-generation operating system that was to feature as many new technologies into Windows, including a new user interface with an object-based file system (this new user interface would officially debut with Windows 95 nearly 4 years later while the object-based file system would later be adopted as WinFS during the development of Windows Vista ). According to Microsoft's product plan at the time, Cairo was planned to be released as late as July 1996 following its development. However, it had become apparent that Cairo was a much more difficult project than Microsoft had anticipated, and the project was subsequently cancelled 5 years into development. A subset of features from Cairo were eventually added into Windows NT 4.0 released on August 24, 1996, albeit without the object file system. Windows NT and Windows 9x would not be truly unified until Windows XP nearly 5 years later, when Microsoft began to merge its consumer and business line of Windows under a singular brand name based on Windows NT. After Windows 3.11 , Microsoft began to develop a new consumer oriented version of the operating system code-named Chicago. Chicago was designed to have support for 32-bit preemptive multitasking, that of which was available in OS/2 and Windows NT, although a 16-bit kernel would remain for the sake of backward compatibility. The Win32 API first introduced with Windows NT was adopted as the standard 32-bit programming interface, with Win16 compatibility being preserved through a technique known as " thunking ". A new GUI was not originally planned as part of the release, although elements of the Cairo user interface were borrowed and added as other aspects of the release (notably Plug and Play) slipped (and indeed after Cairo was cancelled 5 years in development). Microsoft did not change all of the Windows code to 32-bit; parts of it remained 16-bit (albeit not directly using real mode ) for reasons of compatibility, performance and development time. Additionally it was necessary to carry over design decisions from earlier versions of Windows for reasons of backwards compatibility, even if these design decisions no longer matched a more modern computing environment. These factors immediately began to impact the operating system's efficiency and stability. Microsoft marketing adopted Windows 95 as the product name for Chicago when it was released on August 24, 1995. Microsoft went on to release five different versions of Windows 95: OSR2, OSR2.1, and OSR2.5 ("OSR" being an initialism for "OEM Service Release") were not released to the general public, rather, they were available only to OEMs that would preload the OS onto computers. Some companies sold new hard drives with OSR2 preinstalled (officially justifying this as needed due to the hard drive's capacity). The first Microsoft Plus! add-on pack was sold for Windows 95. On June 25, 1998, Microsoft released Windows 98, code-named "Memphis" during development. It included new hardware drivers and better support for the FAT32 file system which allows support for disk partitions larger than the 2 GB maximum accepted by Windows 95. The USB support in Windows 98 was more robust than the basic support provided by the OEM editions of Windows 95. [ 11 ] It also introduces the controversial integration of the Internet Explorer 4 web browser into the Windows shell and File Explorer (then known as Windows Explorer at the time). On June 10, 1999, Microsoft released Windows 98 Second Edition (also known as Windows 98 SE), an interim release whose notable features were the addition of Internet Connection Sharing and improved WDM audio and modem support. Internet Connection Sharing is a form of network address translation , allowing several machines on a LAN (Local Area Network) to share a single Internet connection . It also includes Internet Explorer 5 as opposed to Internet Explorer 4 in the original version. Windows 98 Second Edition also has certain improvements over the original release, and hardware support through device drivers was increased. Many minor problems present in the original release of Windows 98 were also found and fixed. These changes, among others, makes it (according to many) the most stable release of Windows 9x family—to the extent that some commentators used to say that Windows 98's beta version was more stable than Windows 95's final (gamma) version. [ 12 ] Like with Windows 95, Windows 98 received the Microsoft Plus! add-on in the form of Plus! 98 . On September 14, 2000, Microsoft introduced Windows Me (Millennium Edition; also known as Windows ME), which upgraded Windows 98 with enhanced multimedia and Internet features. Code-named "Millennium", It was conceived as a quick one-year project that served as a stopgap release between Windows 98 and Windows XP (then code-named Whistler at the time). It borrowed some features from the business-oriented Windows 2000 into the Windows 9x series, and introduced the first version of System Restore , which allowed users to revert their system state to a previous "known-good" point in the case of a system failure. Windows Me also introduced the first release of Windows Movie Maker and included Windows Media Player 7 . Internet Explorer 5.5 came shipped with Windows Me. Many of the new features from Windows Me were also available as updates for older Windows versions such as Windows 98 via Windows Update . The role of MS-DOS has also been greatly reduced compared to previous versions of Windows, with Windows Me no longer allowing real mode DOS to be accessed. Windows Me initially gained a positive reception upon its release, but later on it was heavily criticized by users for its instability and unreliability, due to frequent freezes and crashes. Windows Me has been viewed by many as one of the worst operating systems of all time, both in critical and in retrospect. PC World was highly critical of Windows Me months after it was released (and indeed when it was no longer available), with their article infamously describing Windows Me as "Mistake Edition" and placing it 4th in their "Worst Tech Products of All Time" feature in 2006. [ 13 ] Consequently, many home users that were affected by Windows Me's instabilities (as well as those who negatively viewed Windows Me) ultimately stuck with the more reliable Windows 98 Second Edition for the remainder of Windows Me's lifecycle until the release of Windows XP in 2001. A small number of Windows Me owners moved over to the business-oriented Windows 2000 Professional during that same time period. The inability of users to easily boot into real mode MS-DOS like in Windows 95 and 98 led users to quickly figure out how to hack their Windows Me installations to provide this missing functionality back into the operating system. [ 14 ] Unlike Windows 95 and Windows 98, Windows Me never received a dedicated Microsoft Plus! add-on made specifically for it. The release of Windows 2000 marked a shift in the user experience between the Windows 9x series and the Windows NT series. Windows NT 4.0, while based on the Windows 95 interface, suffered from a lack of support for USB, Plug and Play and DirectX versions after 3.0, preventing its users from playing contemporary games. Windows 2000 on the other hand, while primarily made towards business and server users, featured an updated user interface and better support for both Plug and Play and USB, as well as including built-in support for DirectX 7.0 . The release of Windows XP in late 2001 confirmed the change of direction for Microsoft, bringing the consumer and business operating systems together under Windows NT. After the release of Windows XP, Microsoft stopped selling Windows 9x releases to end users (and later to OEMs) in the early 2000s. By March 2004, it was impossible to purchase any versions of the Windows 9x series. [ 15 ] Over time, support for the Windows 9x series ended. Windows 95 lost its mainstream support on December 31, 2000, and extended support was dropped from Windows 95 on December 31, 2001 (which also ended support for older Windows versions prior to Windows 95 on that same day). Windows 98 and Windows 98 Second Edition had its mainstream support end on June 30, 2002, and mainstream support for Windows Me ended on December 31, 2003. Microsoft then continued to support the Windows 9x series until July 11, 2006, when extended support ended for Windows 98, Windows 98 Second Edition (SE), and Windows Millennium Edition (Me) – 4 years after extended support for Windows 95 ended on December 31, 2001. [ 16 ] Microsoft DirectX, a set of standard gaming APIs, stopped being updated on Windows 95 at version 8.0a. [ 17 ] It also stopped being updated on Windows 98 and Me after the release of Windows Vista in 2006, making DirectX 9.0c the last version of DirectX to support these operating systems. Support for Microsoft Internet Explorer on all Windows 9x releases have also ended. Windows 95, Windows 98 and Windows Me all lost security patches for Internet Explorer when the respective operating systems reached their end of support date. Internet Explorer 5.5 with Service Pack 2 is the last version of Internet Explorer compatible with Windows 95, while Internet Explorer 6 with Service Pack 1 is the last version compatible with latter releases of Windows 9x (i.e. 98 and Me). [ 18 ] While Internet Explorer 6 for Windows XP did receive security patches up until it lost support, this is not the case for IE6 under Windows 98 and Me. Due to its age, Internet Explorer 7 , the first major update to Internet Explorer 6 in half a decade, was only available for Windows XP SP2 and Windows Vista. In 2011, Microsoft retired the Windows Update v4 website and removed the updates for Windows 98, Windows 98 SE, and Windows Me from its servers. [ 19 ] [ 20 ] [ 21 ] Despite this, an independent project named Windows Update Restored was created in 2022 that aims to restore the Windows Update websites for older versions of Windows, including all releases of Windows 9x. [ 22 ] [ 21 ] Microsoft announced in July 2019 that the Microsoft Internet Games services on Windows Me (and XP) would end on July 31, 2019 (and for Windows 7 on January 22, 2020). [ 23 ] The growing number of important updates caused by the end of life service for these operating systems have slowly made Windows 9x even less practical for everyday use. Today, even open source projects such as Mozilla Firefox will not run on Windows 9x without major rework. [ 24 ] RetroZilla is a fork of Mozilla Application Suite 1.1.xx (running on Gecko 1.8.1 ) aimed at bringing "improved compatibility on the modern web" for versions of Windows as old as Windows 95 and NT 4.0. [ 25 ] The latest version, 2.2, was released in February 2019 and added support for TLS 1.2 . [ 26 ] Windows 9x is a series of monolithic 16/32-bit operating systems. Like most operating systems, Windows 9x consists of kernel space and user space memory. Although Windows 9x features some memory protection , it does not protect the first megabyte of memory from userland applications for compatibility reasons. This area of memory contains code critical to the functioning of the operating system, and by writing into this area of memory an application can crash or freeze the operating system. This was a source of instability as faulty applications could accidentally write into this region, potentially corrupting important operating system memory, which usually resulted in some form of system error and halt. [ 27 ] The user-mode parts of Windows 9x consist of three subsystems: the Win16 subsystem, the Win32 subsystem and MS-DOS. [ 28 ] Windows 9x/Me set aside two blocks of 64 KiB memory regions for GDI and heap resources. By running multiple applications, applications with numerous GDI elements or by running applications over a long span of time, it could exhaust these memory areas. If free system resources dropped below 10%, Windows would become unstable and likely crash. [ 29 ] The kernel mode parts consist of the Virtual Machine Manager (VMM), the Installable File System Manager ( IFSHLP ), the Configuration Manager, and in Windows 98 and later, the WDM Driver Manager (NTKERN). [ 30 ] As a 32-bit operating system, virtual memory space is 4 GiB , divided into a lower 2 GiB for applications and an upper 2 GiB for kernel per process. Like Windows NT, Windows 9x stores user-specific and configuration-specific settings in a large information database called the Windows registry . Hardware-specific settings are also stored in the registry, and many device drivers use the registry to load configuration data. Previous versions of Windows used files such as AUTOEXEC.BAT , CONFIG.SYS , WIN.INI , SYSTEM.INI and other files with an .INI extension to maintain configuration settings. As Windows became more complex and incorporated more features, .INI files became too unwieldy for the limitations of the then-current FAT filesystem. Backwards-compatibility with .INI files was maintained until Windows XP succeeded the 9x and NT lines. Although Microsoft discourages using .INI files in favor of Registry entries, a large number of applications (particularly 16-bit Windows-based applications) still use .INI files. Windows 9x supports .INI files solely for compatibility with those applications and related tools (such as setup programs). The AUTOEXEC.BAT and CONFIG.SYS files also still exist for compatibility with real-mode system components and to allow users to change certain default system settings such as the PATH environment variable. The registry consists of two files: User.dat and System.dat. In Windows Me, Classes.dat was added. The Virtual Machine Manager (VMM) is the 32-bit protected mode kernel at the core of Windows 9x. Its primary responsibility is to create, run, monitor and terminate virtual machines . The VMM provides services that manage memory, processes, interrupts and protection faults. The VMM works with virtual devices (loadable kernel modules, which consist mostly of 32-bit ring 0 or kernel mode code, but may include other types of code, such as a 16-bit real mode initialisation segment) to allow those virtual devices to intercept interrupts and faults to control the access that an application has to hardware devices and installed software. Both the VMM and virtual device drivers run in a single, 32-bit, flat model address space at privilege level 0 (also called ring 0). The VMM provides multi-threaded, preemptive multitasking . It runs multiple applications simultaneously by sharing CPU ( central processing unit ) time between the threads in which the applications and virtual machines run. The VMM is also responsible for creating MS-DOS environments for system processes and Windows applications that still need to run in MS-DOS mode. It is the replacement for vmm.386 in Windows 3.x, and the file vmm32.vxd is a compressed archive containing most of the core VxD, including VMM.vxd itself and ifsmgr.vxd (which facilitates file system access without the need to call the real mode file system code of the DOS kernel). Partial support for Unicode can be installed on Windows 9x through the Microsoft Layer for Unicode. The Windows 9x kernel is usually utilize ANSI encoding . [ 31 ] Windows 9x does not natively support NTFS or HPFS ; however, there are third-party solutions available for Windows 9x that allows read-only access to NTFS volumes. Early versions of Windows 95 did not support FAT32 . Like Windows for Workgroups 3.11 , Windows 9x provides support for 32-bit file access based on IFSHLP.SYS . Unlike Windows 3.x, Windows 9x has support for the VFAT file system, allowing file names with a maximum of 255 characters instead of having 8.3 filenames . Windows 9x has no support for event logging and tracing or error reporting that the Windows NT family of operating systems has, although software like Norton CrashGuard can be used to achieve similar capabilities on Windows 9x. Windows 9x is designed as a single-user system. Thus, the security model is much less effective than the one in Windows NT. One reason for this is the FAT file systems (including FAT12/FAT16/FAT32), which are the only ones that Windows 9x supports officially, though Windows NT also supports FAT12 and FAT16 (but not FAT32; which wouldn’t be supported until Windows 2000) and Windows 9x can be extended to read and write NTFS volumes using third-party Installable File System drivers. FAT systems have very limited security; every user that has access to a FAT drive also has access to all files on that drive. The FAT file systems provide no access control lists and file-system level encryption like NTFS . [ 32 ] Some operating systems that were available at the same time as Windows 9x are either multi-user or have multiple user accounts with different access privileges, which allows important system files (such as the kernel image) to be immutable under most user accounts. In contrast, while Windows 95 and later operating systems offer the option of having profiles for multiple users, they have no concept of access privileges, making them roughly equivalent to a single-user, single-account operating system; this means that all processes can modify all files on the system that aren't open, in addition to being able to modify the boot sector and perform other low-level hard drive modifications. This enables viruses and other clandestinely installed software to integrate themselves with the operating system in a way that is difficult for ordinary users to detect or undo. The profile support in the Windows 9x family is meant for convenience only; unless some registry keys are modified, the system can be accessed by pressing "Cancel" at login, even if all profiles have a password. Windows 95's default login dialog box also allows new user profiles to be created without having to log in first. Users and software can render the operating system unable to function by deleting or overwriting important system files from the hard disk. Users and software are also free to change configuration files in such a way that the operating system is unable to boot or properly function. This phenomenon is not exclusive to Windows 9x; many other operating systems are also susceptible to these vulnerabilities, either by viruses, malware or by the user’s consent. Installation software often replaced and deleted system files without properly checking if the file was still in use or of a newer version. This created a phenomenon often referred to as DLL hell . Windows Me introduced System File Protection and System Restore to handle common problems caused by this issue. Windows 9x offers share-level access control security for file and printer sharing as well as user-level access control if a Windows NT-based operating system is available on the network. [ 33 ] In contrast, Windows NT-based operating systems offer only user-level access control but integrated with the operating system's own user account security mechanism. Device drivers in Windows 9x can be virtual device drivers or (starting with Windows 98) WDM drivers. VxDs usually have the filename extension .vxd or .386 , whereas WDM compatible drivers usually use the extension .sys . The 32-bit VxD message server (msgsrv32) is a program that is able to load virtual device drivers (VxDs) at startup and then handle communication with the drivers. Additionally, the message server performs several background functions, including loading the Windows shell (such as Explorer.exe or Progman.exe ). [ 34 ] Another type of device drivers are .DRV drivers. These drivers are New Executable format and are loaded in user-mode, and are commonly used to control devices such as multimedia devices. To provide access to these devices, a dynamic link library is required (such as MMSYSTEM.DLL). Windows 9x retains backwards compatibility with many drivers made for Windows 3.x and MS-DOS. Using MS-DOS drivers can limit performance and stability due to their use of conventional memory and need to run in real mode which requires the CPU to switch in and out of protected mode. Drivers written for Windows 9x are loaded into the same address space as the kernel. This means that drivers can by accident or design overwrite critical sections of the operating system. Doing this can lead to system crashes, freezes and disk corruption. Faulty operating system drivers were a source of instability for the operating system. Other monolithic and hybrid kernels , like Linux and Windows NT , are also susceptible to malfunctioning drivers impeding the kernel's operation. Often the software developers of drivers and applications had insufficient experience with creating programs for the 'new' system, thus causing many errors which have been generally described as "system errors" by users, even if the error is not caused by parts of Windows or DOS. Microsoft has repeatedly redesigned the Windows Driver architecture since the release of Windows 95 as a result. Windows 9x has no native support for hyper-threading , Data Execution Prevention , symmetric multiprocessing , APIC , or multi-core processors. Windows 9x has no native support for SATA host bus adapters (and neither do Windows 2000 nor Windows XP for that matter), or USB drives (except for Windows Me). There are, however, many SATA-I controllers for which Windows 98/Me drivers exist (and indeed Windows 2000 and Windows XP also provided SATA support via third-party drivers as well), and USB mass storage support has been added to Windows 95 OSR2 and Windows 98 through third party drivers. [ 35 ] [ 36 ] Hardware driver support for Windows 98/Me began to decline in 2005, most notably with motherboard chipsets and video cards . Early versions of Windows 95 had no support for USB or AGP acceleration (including lack of Infrared support for Windows 95 RTM). Windows 95 had preliminary support for ATAPI CD-ROMs, albeit with buggy ATAPI implementation. Windows 95 prior to OSR2 also had buggy support for processors implementing MMX as well as processors based on the P6 microarchitecture . Windows 95 was able to reduce the role of MS-DOS in Windows much further than had been done in Windows 3.1x and earlier. According to Microsoft developer Raymond Chen, MS-DOS served two purposes in Windows 95: as the boot loader, and as the 16-bit legacy device driver layer. [ 37 ] When Windows 95 started up, MS-DOS loaded, processed CONFIG.SYS , launched COMMAND.COM , ran AUTOEXEC.BAT and finally ran WIN.COM . The WIN.COM program used MS-DOS to load the virtual machine manager, read SYSTEM.INI, load the virtual device drivers, and then turn off any running copies of EMM386 and switch into protected mode. Once in protected mode, the virtual device drivers ( VxDs ) transferred all state information from MS-DOS to the 32-bit file system manager, and then shut off MS-DOS. These VxDs allow Windows 9x to interact with hardware resources directly, as providing low-level functionalities such as 32-bit disk access and memory management. All future file system operations would get routed to the 32-bit file system manager. [ 37 ] In Windows Me , win.com was no longer executed during the startup process; instead it went directly to execute VMM32.VXD from IO.SYS. The second role of MS-DOS (as the 16-bit legacy device driver layer) was as a backward compatibility tool for running DOS programs in Windows. Many MS-DOS programs and device drivers interacted with DOS in a low-level way, for example, by patching low-level BIOS interrupts such as int 13h , the low-level disk I/O interrupt. When a program issued an int 21h call to access MS-DOS, the call would go first to the 32-bit file system manager, which would attempt to detect this sort of patching. If it detects that the program has tried to hook into DOS, it will jump back into the 16-bit code to let the hook run. A 16-bit driver called IFSMGR.SYS would previously have been loaded by CONFIG.SYS, the job of which was to hook MS-DOS first before the other drivers and programs got a chance, then jump from 16-bit code back into 32-bit code, when the DOS program had finished, to let the 32-bit file system manager continue its work. [ 37 ] According to Windows developer Raymond Chen , " MS-DOS was just an extremely elaborate decoy. Any 16-bit drivers and programs would patch or hook what they thought was the real MS-DOS, but which was in reality just a decoy. If the 32-bit file system manager detected that somebody bought the decoy, it told the decoy to quack. " [ 37 ] Windows 9x can run MS-DOS applications within itself using a method called "Virtualization", where an application is run on a Virtual DOS machine . Windows 95 and Windows 98 also offer backwards compatibility for DOS applications in the form of being able to boot into a native "DOS Mode" (MS-DOS can be booted without booting Windows, but not putting the CPU in protected mode). Through Windows 9x's memory managers and other post-DOS improvements, the overall system performance and functionality is improved. Some old applications or games may not run properly in the virtual DOS environment within Windows and require real DOS Mode. Having a command line mode outside of the GUI also offers the ability to fix certain system errors without entering the GUI. For example, if a virus is active in GUI mode it can often be safely removed in DOS mode, by deleting its files, which are usually locked while infected in Windows. Similarly, corrupted registry files, system files or boot files can be restored from real mode DOS. Windows 95 and Windows 98 can be started from DOS Mode by typing 'WIN' at the command prompt and then hitting "Enter", akin to earlier versions of Windows such as Windows 3.1. Users can control a Windows 9x-based system through a command-line interface (or CLI) or a graphical user interface (or GUI). The default mode for Windows is usually the graphical user interface, whereas the CLI is available through MS-DOS windows. The GUI provides a means to control the placement and appearance of individual application windows, and interacts with the window system. The GDI , which is a part of the Win32 and Win16 subsystems, is also a module that is loaded in user mode , unlike Windows NT where the GDI is loaded in kernel mode . Alpha compositing and therefore transparency effects, such as fade effects in menus, are not supported by the GDI in Windows 9x, unlike with Windows NT releases since Windows 2000. The default user interface of the GUI is Windows Explorer ; however, a variety of additional Windows shell replacements exist. Other GUIs include LiteStep , bbLean and Program Manager . The sheer popularity of the Windows 9x series led to several web-based projects being created in the 2010s that aimed to replicate the look and feel of Windows 9x (and indeed an actual operating system as a whole) on a single web browser while also invoking nostalgia . Many of these projects (including the ones listed below) are also featured on several websites focusing on older versions of Windows and vintage computing . Developed in 2014, Windows 93 (stylized as "WINDOWS93" in the title bar) is a web-based parody site created by two French musicians and programmers who go by the names of jankenpopp and Zombectro. Being a parody of the Windows 9x series, it is purposefully designed to look and feel like an actual operating system. It features several web applications which reference and features various internet memes from the late 1990s up to the early 2000s. [ 38 ] In 2019, EmuOS was created, which is a web-based site designed to play retro games and applications within a web browser. It was created by Emupedia, a video game preservation and computer history community-based site. The site itself replicates the look and feel of Windows 9x as a whole to emulate an actual Windows operating system, featuring 3 themes based on all major Windows 9x releases starting from Windows 95 up to Windows Me. It also features the aforementioned Windows 93 parody site. [ 39 ] Windows 98 has been recreated in web-based format under the name 98.js (also known as Windows 98 Online). It featured web-based versions of several classic Windows applications. [ 40 ] [ 41 ]	https://en.wikipedia.org/wiki/Windows_9x
Windows Calculator is a software calculator developed by Microsoft and included in Windows . In its Windows 10 incarnation it has four modes: standard, scientific, programmer, and a graphing mode. The standard mode includes a number pad and buttons for performing arithmetic operations. The scientific mode takes this a step further and adds exponents and trigonometric function, and programmer mode allows the user to perform operations related to computer programming . In 2020, a graphing mode was added to the Calculator, allowing users to graph equations on a coordinate plane. [ 3 ] The Windows Calculator is one of a few applications that have been bundled in all versions of Windows, starting with Windows 1.0 . Since then, the calculator has been upgraded with various capabilities. In addition, the calculator has also been included with Windows Phone [ 4 ] and Xbox One . [ citation needed ] The Microsoft Store page proclaims HoloLens support as of February 2024, but the Calculator app is not installed on HoloLens by default. A simple arithmetic calculator was first included with Windows 1.0 . [ 5 ] In Windows 3.0 , a scientific mode was added, which included exponents and roots , logarithms , factorial -based functions, trigonometry (supports radian , degree and gradians angles), base conversions (2, 8, 10, 16), logic operations, statistical functions such as single variable statistics and linear regression. Until Windows 95 , it uses an IEEE 754-1985 double-precision floating-point , and the highest representable number by the calculator is 2 1024 , which is slightly above 10 308 (≈1.80 × 10 308 ). In Windows 98 and later, it uses an arbitrary-precision arithmetic library, replacing the standard IEEE floating point library. [ 6 ] It offers bignum precision for basic operations (addition, subtraction, multiplication, division) and 32 digits of precision for advanced operations ( square root , transcendental functions ). The largest value that can be represented on the Windows Calculator is currently <10 10,000 and the smallest is 10 −9,999 . (Also ! calculates the gamma function which is defined over all real numbers, only excluding the negative integers). In Windows 2000 , digit grouping is added. Degree and base settings are added to menu bar. The calculators of Windows XP and Vista were able to calculate using numbers beyond 10 10000 , but calculating with these numbers (e.g. 10^2^2^2^2^2^2^2...) does increasingly slow down the calculator and make it unresponsive until the calculation has been completed. Unlike later versions, calculating with binary / decimal / hexadecimal / octal numbers is included into scientific mode. In Windows 7 , separate programmer, statistics, unit conversion, date calculation, and worksheets modes were added. Tooltips were removed. Furthermore, Calculator's interface was revamped for the first time since its introduction. The base conversion functions were moved to the programmer mode and statistics functions were moved to the statistics mode. Switching between modes does not preserve the current number, clearing it to 0. The highest number is now limited to 10 10000 again. In every mode except programmer mode, one can see the history of calculations. The app was redesigned to accommodate multi-touch . Standard mode behaves as a simple checkbook calculator; entering the sequence 6 * 4 + 12 / 4 - 4 * 5 gives the answer 25. In scientific mode, order of operations is followed while doing calculations (multiplication and division are done before addition and subtraction), which means 6 * 4 + 12 / 4 - 4 * 5 = 7 . In programmer mode, inputting a number in decimal has a lower and upper limit, depending on the data type, and must always be an integer. Data type of number in decimal mode is signed n-bit [ 7 ] integer when converting from number in hexadecimal, octal, or binary mode. On the right side of the main Calculator [ clarification needed ] , one can add a panel with date calculation, unit conversion and worksheets. Worksheets allow one to calculate a result of a chosen field based on the values of other fields. Pre-defined templates include calculating a car's fuel economy (mpg and L/100 km), [ 8 ] a vehicle lease, and a mortgage. In pre-beta versions of Windows 7, Calculator also provided a Wages template. While the traditional Calculator is still included with Windows 8.1 , a Metro-style Calculator is also present, featuring a full-screen interface as well as normal, scientific, and conversion modes. [ 9 ] The Calculator in non-LTSC editions of Windows 10 is a Universal Windows Platform app . In contrast, Windows 10 LTSC (which does not include universal Windows apps) includes the traditional calculator, but which is now named win32calc.exe . Both calculators provide the features of the traditional calculator included with Windows 7 and Windows 8.x, such as unit conversions for volume, length, weight, temperature, energy, area, speed, time, power, data, pressure and angle, and the history list which the user can clear. Both the universal Windows app and LTSC's win32calc.exe register themselves with the system as handlers of a ' calculator: ' pseudo-protocol. This registration is similar to that performed by any other well-behaved application when it registers itself as a handler for a filetype (e.g. .jpg ) or protocol (e.g. http: ). All Windows 10 editions (both LTSC and non-LTSC) continue to have a calc.exe , which however is just a stub that launches (via ShellExecute) the handler that is associated with the ' calculator: ' pseudo-protocol. As with any other protocol or filetype, when there are multiple handlers to choose from, users are free to choose which handler they prefer— either via the classic control panel ('Default programs' settings) or the immersive UI settings ('Default Apps' settings) or from the command prompt via OpenWith calculator: . In the Windows 10 Fall Creators Update, a currency converter mode was added to Calculator. [ 10 ] On 6 March 2019, Microsoft released the source code for Calculator on GitHub under the MIT License . [ 11 ] In Windows 11, the Calculator app's user interface was modified to match the design of Windows 11 and a new settings page is present for users to toggle between the themes of the app without changing the operating system's theme. In 2021, Microsoft announced it would migrate the codebase of the Calculator app to C# in order to welcome more developers to contribute to the app. By default, Calculator runs in standard mode, which resembles a four-function calculator. More advanced functions are available in scientific mode, including logarithms , numerical base conversions, some logical operators , operator precedence , radian , degree and gradians support as well as simple single-variable statistical functions. It does not provide support for user-defined functions, complex numbers , storage variables for intermediate results (other than the classic accumulator memory of pocket calculators), automated polar - Cartesian coordinates conversion, or support for two-variables statistics. In addition, the programming mode allows conversions between bases 16, 10, 8, and 2, the most commonly used by programmers. In this mode, the on-screen numeric keypad includes the hexadecimal digits A through F, which are active when "Hex" is selected. In hex mode, only integers are supported. Calculator supports keyboard shortcuts ; all Calculator features have an associated keyboard shortcut. [ 12 ] Calculator in programmer mode cannot accept or display a number larger than a signed QWORD (16 hexadecimal digits/64 bits). The largest number it can handle is therefore 0x7FFFFFFFFFFFFFFF (decimal 9,223,372,036,854,775,807). Any calculations in programmer mode which exceed this limit will overflow , even if those calculations would succeed in other modes. In particular, scientific notation is not available in this mode. Calculator Plus is a separate application for Windows XP and Windows Server 2003 users that adds a 'Conversion' mode over the Windows XP version of the Calculator. The 'Conversion' mode supports unit conversion and currency conversion . Currency exchange rates can be updated using the built-in update feature, which downloads exchange rates from the European Central Bank . [ 15 ] [ 16 ]	https://en.wikipedia.org/wiki/Windows_Calculator
Windows ChallengE was a programming competition run by Microsoft Corporation . The contest is composed of teams of 3 or 4 students at colleges / universities from around the world, along with a faculty mentor. The only requirement of the contest is that the teams utilize the hardware provided to them (an eBoxII from ICOPTech ), as well as build a customized image of the Windows CE operating system . The first Windows ChallengE was held in 2004, consisting of less than 30 teams within the United States. The goal was to use Windows CE to "Make the World a Safer Place". James Madison University won the contest, led by students Marcus O'Malley, Joshua Blake, Justin Creasy and Kevin Ferrell. Computer science professor Ramon A. Mata-Toledo served as team adviser. Their winning project was an airport security checkpoint device designed to help protect the millions of people who fly daily. The mobile handheld device collects information from a passenger's boarding pass and uses a chemical sniffer to sense and identify potential high-security risks posed by baggage or passengers. In 2005, it was opened to the rest of the world. 278 teams from all over the world participated. The winner of the 2005 contest was the team from the Royal Melbourne Institute of Technology (RMIT), Australia , with the "EverGreen" project. [ 1 ] In 2006 more than 300 teams registered for the contest. The final was held in Redmond, WA, at the Microsoft Campus. In the finals only 20 teams participated, among which only 12 made it to the last day of the competition. The 44Tech team of Romania won the contest with their project "Forest Watcher". That team was composed of Cristian Pop, Ioana Bratie, Omar Choudary and Mircea Gheorghe. In 2007 the contest became part of the Imagine Cup. Imagine Cup is a bigger competition, also organized by Microsoft, which is composed of several competition tracks, including algorithms, photography, embedded software. This computing article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Windows_ChallengE
Windows Easy Transfer was a specialized file-transfer program developed by Microsoft that allowed users of the Windows operating system to transfer personal files and settings from a computer running an earlier version of Windows to a computer running a newer version. [ 1 ] Windows Easy Transfer was introduced in Windows Vista and included in Windows 7 , Windows 8 , and Windows 8.1 . It replaced the Files and Settings Transfer Wizard included with Windows XP and offered limited migration services for computers running Windows 2000 SP4 and Windows XP SP2. [ 2 ] For all versions of Windows, it did not transfer applications—only files and settings. [ 3 ] Microsoft incorporated a key technology into the Windows Easy Transfer tool based on its acquisition of Apptimum in 2006. [ 4 ] Apptimum's technology complemented the transfer experience offered across multiple Windows operating systems, including Windows Vista, 7, 8.1, and 10. [ 4 ] Windows Easy Transfer was discontinued with Windows 10 . [ 5 ] From September 1, 2015 to August 31, 2016, Microsoft partnered with Laplink to provide a free download of PCmover Express, which allowed 500 MB of data and settings to be transferred from at least Windows XP to either Windows 8.1 or Windows 10. [ 6 ] For Windows 2000, Microsoft developed the User State Migration Tool command line utility that allowed users of Windows 95 , 98 , and NT 4.0 to migrate their data and settings to the newer operating system; it did not provide a graphical user interface . [ 7 ] An additional migration tool, Files and Settings Transfer Wizard ( migwiz.exe ) was developed for Windows XP to facilitate the migration of data and settings from Windows 98 and Windows Me . [ 8 ] It could be launched from the Windows XP CD-ROM and presented options to transfer data and settings via a 3.5-inch floppy , computer network , direct cable connection , or a Zip disk . Users could also create a wizard disk to initiate the migration process when run from earlier operating system. [ 7 ] A preliminary version of Windows Easy Transfer was demonstrated at the 2004 Windows Hardware Engineering Conference by Jim Allchin as the successor to the Files and Settings Transfer Wizard, scheduled for release in the next client version of Windows, Windows Vista (then codenamed "Longhorn"). As with the final release, this preliminary version could use an optional specialized USB cable to transfer data between computers. [ 9 ] After the release to manufacturing of Windows 7, Microsoft backported the version of Windows Easy Transfer in that operating system to Windows XP and Windows Vista as an optional download to facilitate migration to the new operating system. Windows Easy Transfer could transfer: [ 1 ] [ 10 ] For transferring from Windows versions later than Windows 2000: As of Windows 8.1, Easy Transfer can no longer export data to another computer, but can still open files created on an earlier version of Windows. [ 11 ] Windows Easy Transfer did not support transferring installed applications. [ 1 ] [ 12 ] [ 13 ] Microsoft planned to release a supplementary Windows Easy Transfer Companion for transferring certain supported applications from Windows XP to Windows Vista, but it remained as a perpetual beta during development and a final version was never released. [ 14 ] Several transfer methods could be used: [ 1 ] Windows Easy Transfer did not support migration from a 64-bit to a 32-bit system. [ 16 ] Windows Vista and later versions did not support incoming connections over IrDA , serial , or parallel ports , but incoming connections over Ethernet , HPNA , and wireless LAN were supported. [ 17 ] In Windows 8.1, Windows Easy Transfer could only import settings from Windows 7, 8, and RT , but not from Windows Vista or from another Windows 8.1 computer. [ 18 ] The only transfer method supported in Windows 8.1 is by a USB flash drive; transfers by an Easy Transfer Cable or a network connection are not supported. [ 19 ]	https://en.wikipedia.org/wiki/Windows_Easy_Transfer
Windows Hardware Error Architecture ( WHEA ) is an operating system hardware error handling mechanism introduced with Windows Vista SP1 and Windows Server 2008 as a successor to Machine Check Architecture (MCA) on previous versions of Windows . [ 1 ] The architecture consists of several software components that interact with the hardware and firmware of a given platform to handle and notify regarding hardware error conditions. [ 2 ] Collectively, these components provide: a generic means of discovering errors, a common error report format for those errors, a way of preserving error records, and an error event model based up on Event Tracing for Windows (ETW). [ 3 ] WHEA "builds on the PCI Express Advanced Reporting to provide more detailed information about system errors and a common reporting structure." [ 4 ] WHEA allows third-party software to interact with the operating system and react to certain hardware events. For example, when a new CPU is added to a running system—a Windows Server feature known as Dynamic Hardware Partitioning —the hardware error component stack is notified that a new processor was installed. [ 5 ] In contrast, Linux supports the ACPI Platform Error Interface (APEI) which is introduced in ACPI 5.0. [ 6 ]	https://en.wikipedia.org/wiki/Windows_Hardware_Error_Architecture
The Windows Metafile vulnerability —also called the Metafile Image Code Execution and abbreviated MICE —is a security vulnerability in the way some versions of the Microsoft Windows operating system handled images in the Windows Metafile format. It permits arbitrary code to be executed on affected computers without the permission of their users. It was discovered on December 27, 2005, and the first reports of affected computers were announced within 24 hours. Microsoft released a high-priority update to eliminate this vulnerability via Windows Update on January 5, 2006. [ 1 ] Attacks using this vulnerability are known as WMF exploits . The vulnerability was located in gdi32.dll and existed in all versions of Microsoft Windows from Windows 3.0 to Windows Server 2003 R2 . However, attack vectors only exist in NT-based versions of Windows (Windows NT, Windows 2000 , Windows XP and Windows Server 2003 ). Exploits taking advantage of the vulnerability on Windows NT -based systems facilitated the propagation of various types of malware , typically through drive-by downloads . Due to extreme impact, this bug won the 2007 Pwnie Award for "Mass 0wnage" and "Breaking the Internet". All versions of the Microsoft Windows operating system support the Windows Metafile graphics standard. All versions from Windows 3.0 to Windows Server 2003 R2 contain this security flaw. [ 2 ] However, Windows NT 4.0 and Windows XP , unless patched , are more vulnerable than earlier versions because their default installation enables Windows Metafile code execution, the source of the vulnerability. [ 3 ] Later versions of Windows do not have this vulnerability. [ 2 ] According to computer security expert Steve Gibson , Windows NT 4 is vulnerable to known exploits if image preview is enabled. [ 3 ] Windows operating systems that do not have image preview enabled or that have hardware-based Data Execution Prevention (DEP) active for all applications should not be susceptible to this exploit. [ 4 ] Operating systems other than Windows (e.g., macOS , Unix , Linux , etc.) are not directly affected. However, a non-Windows system could become vulnerable if it runs software to view Windows WMF files. This could include software that incorporates or clones Windows' native Graphics Device Interface (GDI) Dynamic-link library (DLL) [1] or that run Windows or Windows programs through an emulator or compatibility layer . A Unix-like system that uses Wine to emulate Windows, for example, could be exploited. [ 5 ] Gibson wrote the program MouseTrap, which his company distributes as freeware , to detect Windows Metafile vulnerability in systems running Windows and Windows emulators. [ 3 ] According to assessments by F-Secure , [2] the vulnerability is an inherent defect in the design of WMF files, because the underlying architecture of such files is from a previous era , and includes features which allow actual code to be executed whenever a WMF file opens. The original purpose of this was mainly to handle the cancellation of print jobs during spooling . According to Secunia , "The vulnerability is caused due to an error in the handling of Windows Metafile files ('.wmf') containing specially crafted SETABORTPROC 'Escape' records. Such records allow arbitrary user-defined function to be executed when the rendering of a WMF file fails." According to the Windows 3.1 SDK documentation, the SETABORTPROC escape was obsoleted and replaced by the function of the same name in Windows 3.1, long before the WMF vulnerability was discovered. However the obsoleted escape code was retained for compatibility with 16 bit programs written for (or at least backwards compatible with) Windows 3.0. This change happened at approximately the same time as Microsoft was creating the 32 bit reimplementation of GDI for Windows NT, and it is likely that the vulnerability occurred during this effort. The 'Escape' mechanism in question allows applications (not metafiles) to access output device features not yet abstracted by GDI, such as hardware accelerated Bézier curves , encapsulated postscript support, etc. This is done by passing an opcode, a size and a pointer to some data to the call, which will usually just pass it on to the driver. Because most Escape calls produce actual graphics, the general escape mechanism is allowed in metafiles with little thought originally given to the possibility of using it for things like SETABORTPROC, modern non-vulnerable metafile interpreters now checks the opcode against a blacklist or whitelist, while keeping the full set of opcodes available to regular code that calls the GDI escape functions directly (because such code is already running in the same way as the code it could make GDI call, there is no security risk in that case). It is worth noting that 16 bit Windows (except the rarely used Real mode of Windows 3.0) was immune to the vulnerability because the pointer specified in the metafile can only point to data within the metafile, and 16 bit Windows always had a full no-execute-data enforcement mandated by the segmented architecture of 16 bit protected mode. Windows NT for CPU architectures other than 32 bit x86 (such as MIPS, PowerPC, Alpha, Itanium and x86_64) required return-oriented programming to exploit because those architectures had the no-execute functionality missing from older x86 processors. The vulnerability is CVE - 2005-4560 in the Common Vulnerabilities and Exposures database, US-CERT reference VU#181038 and Microsoft Knowledge Base Article 912840. It was first observed in the wild by researchers at Sunbelt Software on December 28, 2005, and announced publicly by the company's president Alex Eckelberry . [ 6 ] [ 7 ] Computers can be affected via the spread of infected e-mails which carry the hacked WMF file as an attachment . Infection may also result from: Other methods may also be used to propagate infection. Because the problem is within the operating system, using non-Microsoft browsers such as Firefox or Opera does not provide complete protection. Users are typically prompted to download and view a malicious file, infecting the computer. Infected files may be downloaded automatically , which opens the possibility for infection by disk indexing or accidental previewing. According to assessments from the McAfee antivirus company, [3] the vulnerability has been used to propagate the Bifrost backdoor trojan horse . Other forms of malware have also exploited the vulnerability to deliver various malicious payloads . McAfee claims that the first generation of such exploits had been encountered by more than 6% of their customer base by December 31, 2005. Microsoft released an official patch to address the problem on January 5, 2006. [ 8 ] This patch may be applied in lieu of other corrective measures. The official patch is available for Windows 2000 , Windows XP and Microsoft Windows Server 2003 . Windows NT 4 and other older operating systems did not receive a patch as they were no longer supported by Microsoft by then. Steve Gibson stated in his Security Now! podcast No. 20, that his company Gibson Research Corporation would make a patch available for Windows 9x systems if Microsoft did not. [ 9 ] After further research, Steve Gibson stated, in a later Security Now! podcast No. 23, that Windows 9x and ME are not vulnerable and do not need patching. [ 10 ] Windows 9x/ME users can run his Mouse Trap utility to see this for themselves. A free downloadable patch for Windows NT [ 11 ] has been provided by Paolo Monti from Future Time, the Italian distributor of Eset 's NOD32 anti-virus system. The patch works on older operating systems, but it is supplied without warranty. There have been reports of the official patch being automatically installed even when Windows Automatic Update is configured to ask before installing automatically downloaded updates. This causes an automatic reboot , which can cause loss of data if the user has a program open with unsaved changes. [4] These measures are of historical interest only on systems updated on or after January 5, 2006. As a workaround before a patch was available, [5] on December 28, 2005, Microsoft advised Windows users to unregister the dynamic-link library file shimgvw.dll (which can be done by executing the command regsvr32.exe /u shimgvw.dll from the Run menu or the command prompt ) which invokes previewing of image files and is exploited by most of these attacks. The DLL can be re-registered after patching by running regsvr32.exe shimgvw.dll . This workaround blocks a common attack vector but does not eliminate the vulnerability. A third party patch [6] was released by Ilfak Guilfanov on December 31, 2005, to temporarily disable the vulnerable function call in gdi32.dll. This unofficial patch received much publicity due to the unavailability of an official one from Microsoft, receiving the recommendation of SANS Institute Internet Storm Center [7] and F-Secure. [8] Because of the large amount of publicity, including being indirectly slashdotted , [9] Guilfanov's website received more visitors than it could cope with, and was suspended on January 3, 2006; the patch was still available for download from a number of mirrors including the Internet Storm Center website. [10] Guilfanov's website went back online on January 4 in a much-reduced state. No longer providing the patch on-site due to bandwidth issues, the homepage provided a list of mirrors where a user could download the patch and the associated vulnerability-checker, and the MD5 checksum for the file, so that it could be checked that a downloaded file was probably genuine. After Microsoft released its patch, Guilfanov withdrew his. Microsoft says its patch removes the flawed functionality in GDI32 that allowed the WMF vulnerability. For computers running an unpatched version of Windows, a defence in depth approach was recommended, to mitigate the risk of infection. Various sources have recommended mitigation efforts that include: According to SANS Institute Internet Storm Center article, using a web browser other than Internet Explorer may offer additional protection against this vulnerability. [ 12 ] Depending on settings, these browsers may ask the user before opening an image with the .wmf extension, but this only reduces the chance of opening the maliciously crafted Windows Metafile, and does not protect against the vulnerability being exploited as these browsers still open the metafile if it is masquerading as another format. It is better to entirely disable image loading in any browser used. In 2006 Steve Gibson suggested that the peculiar nature of the 'bug' was an indication that the vulnerability was actually a backdoor intentionally engineered into the system. [ 13 ] The accusation became an assertion and spread through the internet as a rumor after the technology news website Slashdot picked up Gibson's speculation. [ 13 ] The rumor was widely debunked [ 14 ] [ 15 ] and Thomas Greene, writing in The Register , attributed Gibson's mistake to "his lack of security experience" and called him a "popinjay expert". [ 13 ]	https://en.wikipedia.org/wiki/Windows_Metafile_vulnerability
Windows NT 3.1 is the first major release of the Windows NT operating system developed by Microsoft , released on July 27, 1993. It marked the company's entry into the corporate computing environment, designed to support large networks and to be portable, compiled for Intel x86 , DEC Alpha and MIPS based workstations and servers . [ 3 ] It was Microsoft's first 32-bit operating system, providing advantages over the constrictive 16-bit architecture of previous versions of Windows that relied on DOS , but retaining a desktop environment familiar to Windows 3.1 users. [ 3 ] Windows NT began as a rewrite of the OS/2 operating system, which Microsoft had co-developed with IBM but failed to gain much traction against Unix , with vendor Sun Microsystems dominating the market for powerful desktop workstations. [ 4 ] For several reasons, including the market success of Windows 3.0 in 1990, Microsoft decided to advance Windows rather than OS/2 and relinquished their OS/2 development responsibilities. By extending the Windows brand and beginning NT at version 3.1, like Windows 3.1 which had established brand recognition and market share , Microsoft implied that consumers should expect a familiar user experience . The name Windows NT ("New Technology") advertised that this was a re-engineered version of Windows. First publicly demonstrated at Comdex 1991, NT 3.1 was released in 1993 in two editions: Workstation and Advanced Server. When Windows NT premiered, their sales were limited by high system requirements , and a general lack of 32-bit applications to take advantage of the OS's data processing capabilities. It sold about 300,000 copies before it was succeeded by Windows NT 3.5 in 1994. On December 31, 2000, Microsoft declared Windows NT 3.1 obsolete and stopped providing support and updates for the system. Windows NT 3.1 was the first version of Windows to use 32-bit flat virtual memory addressing on 32-bit processors. Its companion product, Windows 3.1, used segmented addressing and switches from 16-bit to 32-bit addressing in pages. The origins of Windows NT date back to 1988, [ 5 ] where Microsoft had a major foothold on the personal computer market due to the use of its MS-DOS as the operating system of IBM PC compatibles . Nathan Myhrvold , who had joined Microsoft after its acquisition of Dynamical Systems Research, identified two major threats to Microsoft's monopoly— RISC architectures, which proved to be more powerful than the equivalent Intel processors that MS-DOS ran on, and Unix , a family of cross-platform multitasking operating systems with support for multiprocessing and networking . [ 6 ] : 34 While the widespread use of Unix was hindered by the need to adapt programs for each individual variant, Bill Gates believed that the combination of a Unix-like operating system with RISC processors could be a market threat, prompting the need for Microsoft to develop a "Unix killer" that could run on multiple architectures. [ 6 ] : 35 Myhrvold wanted to develop a new system that would run on RISC workstations and Intel chips and multiprocessing computers. [ 5 ] Gates had also hired Dave Cutler from Digital Equipment Corporation to assist in developing the new operating system; Cutler left DEC after the cancellation of the PRISM architecture and its MICA operating system, and agreed to join Microsoft on the condition that he be able to bring a number of staff members from his team at DEC with him. [ 5 ] [ 6 ] : 17–37 Cutler arrived at Microsoft in October 1988, and began working on the development of the operating system in November. [ 6 ] : 38 [ 7 ] The operating system was first developed as a revised version of OS/2 , an operating system Microsoft had jointly developed with IBM . [ 8 ] : 43–44 While OS/2 was originally intended to succeed MS-DOS, it had yet to be commercially successful. The OS was to be designed so it could be ported to different processor platforms, and support multiprocessor systems, which few operating systems did at that time. [ 6 ] : 33 [ 8 ] : 2 [ 9 ] To target the enterprise market, the OS was also to support networking, the POSIX standard, and a security platform compliant with the " Orange Book " standards; which would require the OS to be a multi-user system with a permission framework and the ability to audit security-related events. [ 10 ] Both Microsoft and IBM wanted to market an operating system that appealed to corporate " enterprise software " customers. That meant greater security , reliability , processing power, and computer networking features. However, since Microsoft also wanted to capture market share from Unix on other computing platforms , they needed a system design that was more portable than that of OS/2. To this end, Microsoft began by developing and testing their new operating system for a non- x86 processor: an emulated version of the Intel i860 . Alluding to the chip's codename, "N10", Microsoft codenamed their operating system NT OS/2 . [ 11 ] DEC preemptively sued Microsoft, alleging that they stole code from MICA for use in the new operating system. In an out-of-court settlement, Microsoft agreed to make NT OS/2 compatible with DEC's Alpha processor . [ 7 ] The development team originally estimated that development would be complete within 18 months. By April 1989, the NT OS/2 kernel could run inside the i860 emulator. However, the development team later determined that the i860 was unsuitable for the project. By December they had begun porting NT OS/2 to the MIPS R3000 processor instead, and completed the task in three months. [ 11 ] Senior Microsoft executive Paul Maritz was targeting a release date in 1992, but the development schedule was uncertain. The company was eager to silence naysayers who speculated that NT wouldn't be on the market until 1994, and had planned to present the new OS at COMDEX in 1990. [ 8 ] : 84–85 In May 1990, Microsoft released Windows 3.0 , a new version of its MS-DOS-based Windows desktop environment . Windows 3.0 sold well, and the resulting shift in Microsoft's marketing strategy eroded their partnership with IBM—who wanted Microsoft to concentrate solely on developing OS/2 as its primary platform as opposed to building their future business around Windows. [ 6 ] : 100 Users and developers were unsure of whether to adopt Windows or OS/2 due to these uncertainties (a situation magnified by the fact that the operating systems were incompatible with each other at the API level), while Microsoft's resources were also being drained by the simultaneous development of multiple operating systems. [ 8 ] : 98–99 [ 12 ] In August 1990, as a response to the popularity of Windows 3.0, the NT OS/2 team decided to re-work the operating system to use an extended 32-bit port of the Windows API known as Win32. Win32 maintained the familiar structure of the 16-bit APIs used by Windows, which would allow developers to easily adapt their software for the new platform while maintaining a level of compatibility with existing software for Windows. [ 13 ] With the shift to a Windows-like architecture, the operating system's shell was also changed from OS/2's Presentation Manager to Windows' Program Manager . [ 6 ] : 102–105 Due to these changes, NT was not presented at COMDEX 1990 as was originally planned. [ 6 ] : 102 Neither the general public nor IBM knew about the transformation of NT OS/2 into Windows NT at the time. [ 6 ] : 108 Although the companies did agree to a revised partnership where IBM and Microsoft would alternate developing major versions of OS/2 instead of collaborating on each version, [ 14 ] IBM eventually learned of Microsoft's Windows NT plans in January 1991, and immediately ended the OS/2 partnership. IBM would solely develop OS/2 2.0 (as was planned under the amended version) and all future versions, without any further involvement from Microsoft. [ 8 ] : 108–109 [ 13 ] In October 1991, Windows NT received its first public demonstration at COMDEX. In an effort to ensure software taking advantage of Windows NT was available upon its release (scheduled for late-1992), Microsoft also distributed a 32-bit software development kit to selected developers in attendance. [ 6 ] : 165 [ 15 ] The demonstration was positively received; PC Magazine called Windows NT "the modern reinvention of the operating system", but at the same time claimed that it was unlikely that the promised backward compatibility would be kept for the final release. [ 8 ] : 175–176 [ 16 ] In March 1992, Microsoft also released Win32s , which would allow Windows 3.1 to have partial compatibility with Windows NT programs for the purposes of developing software optimized for the platform. [ 17 ] At Microsoft's Win32 Professional Developers Conference in June 1992, Windows NT was demonstrated running on x86 and MIPS processors, while a beta version of Windows NT and an updated development kit were also made available. [ 18 ] Concurrently, Microsoft announced a new version of its SQL Server product for Windows NT; Unix vendors feared that the software could be a killer app that would affect the market share of Unix systems. [ 19 ] [ 20 ] Concerns were also raised over NT's memory usage; while most computers of the era shipped with 4 megabytes of RAM , 16 MB was recommended for NTs. Due to the high cost of RAM at the time, critics thought that its high system requirements could affect the sales and adoption of Windows NT. Steps were taken to reduce its memory usage through methods such as paging . [ 8 ] : 227–249 Microsoft began releasing public beta builds of NT in October 1992, and a month later at COMDEX, a presentation focusing on third-party software for Windows NT was held. [ 21 ] [ 22 ] [ 23 ] The final pre-release version of NT was released in March 1993, alongside the unveiling of the server version, LAN Manager for Windows NT . Although its stability and performance had improved, there were still fears that the OS could be released in an unfinished state or delayed further into 1993. [ 24 ] [ 25 ] By extending the Windows brand and beginning NT at version 3.1, like Windows 3.1 which had established brand recognition and market share , Microsoft implied that consumers should expect a familiar user experience yet re-engineered. Windows NT 3.1 and Windows NT 3.1 Advanced Server (so numbered to associate them with Windows 3.1 ) were released on July 26, 1993. [ 6 ] : 300 At first, only the x86 and MIPS versions shipped; the DEC Alpha version followed in September. [ 11 ] [ 26 ] Microsoft sold the workstation version for $495 , and the server version for $1,495 . Ostensibly, the server price was meant to be a promotional discount offered only during the first six months of sale, but they never raised the retail price to the listed one— $2,995 . [ 27 ] [ 28 ] 250 programmers [ 29 ] wrote 5.6 million lines of code ; [ 6 ] : 290 the development cost $150 million . [ 6 ] : 307 In the last year of development, the team fixed more than 30,000 bugs. [ 6 ] : 300 During the product's lifecycle, Microsoft published three service packs : Service Pack 1 was released on October 8, 1993; Service Pack 2 followed on January 24, 1994; and Service Pack 3's release date was October 29, 1994. The service packs were distributed on CD-ROM and floppy disk, and also through bulletin board systems , CompuServe , and the Internet . Microsoft terminated support for the operating system on December 31, 2000. Support for Windows NT 3.1 RTM (without a service pack) ended on January 8, 1994. Service Pack 1 support ended on April 24, 1994, and finally, Service Pack 2 support ended on January 29, 1995, only 1 year after general availability. Windows NT 3.1 was localized into various languages. Besides English, it was available in Dutch, French, German, Japanese, Spanish and Swedish. The version for workstations, but not Windows NT 3.1 Server, was additionally available in Danish, Finnish, Italian, Norwegian and Portuguese. [ 30 ] Cutler set three main goals for Windows NT. The first goal was portability: in contrast to previous operating systems, which were strongly tied to one architecture, Windows NT should be able to operate on multiple architectures. [ 6 ] : 53 To meet this goal, most of the operating systems, including the operating system core, had to be written in the C programming language . [ 31 ] During the planning phase it was clear that this would cause Windows NT to have higher memory consumption than all previous operating systems. [ 6 ] : 55 Besides the graphics system and parts of the networking system, which were written in C++ , only parts of the operating systems which required direct hardware access and performance critical functions were written in assembly language . These parts were isolated so that they could easily be rewritten when porting the operating system to a new architecture. [ 8 ] : 89 The second goal was reliability : The system should no longer crash due to a faulty application or faulty hardware. [ 8 ] : 9 This way, the operating system should be made attractive for critical applications. [ 6 ] : 54 To meet this goal, the architecture of Windows NT was designed so that the operating system core was isolated and applications could not access it directly. [ 6 ] : 56 The kernel was designed as a microkernel and components of the core were to run atop the kernel in a modular fashion; Cutler knew this principle from his work at Digital. [ 6 ] : 57 Reliability also includes security, and the operating system should be able to resist external attacks. [ 8 ] : 9 Mainframes already had a system where every user had their own account which was assigned specific rights by the administrator , this way, users could be prevented access to confidential documents. [ 8 ] : 157–158 A virtual memory management was designed to thwart attacks by malware and prevent users from accessing foreign areas of memory. [ 8 ] : 10 The third goal was called personality : The operating system should be able to run applications designed for various operating systems, such as Windows , MS-DOS and OS/2 applications. [ 6 ] : 54 The Mach kernel followed a similar concept by moving the APIs to components which operated in user mode as applications, these could be changed and new ones could be added. This principle was applied to Windows NT. [ 8 ] : 6 Despite all these goals, the performance of the operating system was optimized where possible, by adapting critical sections of the code to fast execution speed. To improve networking performance, large parts of the networking system were moved to the operating system core. [ 8 ] : 12 Windows NT was designed as a networking operating system. In this branch, Novell had a lead with its product NetWare , mostly because of a lack of competition, and Microsoft failed to develop a product which could challenge NetWare's lead. Cutler hoped to gain additional customers with a reliable networking operating system. [ 6 ] : 65 Bill Gates already dominated the market of desktop operating systems with MS-DOS and Windows and hoped to do the same in the networking market with Windows NT. [ 6 ] : 3 He especially hoped to find a market in the emerging number of servers, while at the same time he did not expect a success in the desktop market until 1995. [ 6 ] : 151 Therefore, Windows NT was positioned as a high-end operating system in an interview with the product manager David Thacher. It was not designed to replace Windows 3.1 completely, but it should rather supplement Microsoft's product palette with an operating system for critical applications. The expectations were 10% to 20% among all Windows sales [ 29 ] and a market share of 10% in the high end market, which amounted to one million copies. [ 32 ] While Windows NT 3.1 uses the same graphical user interface as Windows 3.1, it was developed anew. The operating system is not DOS-based, but an independent 32-bit operating system; many concepts were taken from Cutler's previous operating system, VMS . [ 31 ] The architecture of Windows NT takes some ideas of the client–server model , like the modular structure and the communication between the modules. [ 8 ] : 20 System resources like memory, files or devices are viewed as objects by the operating system, which are all accessed in the same way through handles and which can in this way be secured against unauthorized access. [ 8 ] : 22–23 The operating system was designed for multiprocessor systems; it supports preemptive multitasking [ 8 ] : 92 and can make use of threads to run multiple processes in parallel. [ 8 ] : 94 Using symmetric multiprocessing , the processing usage is evenly distributed among all available processors. [ 8 ] : 24 The inter-process communication in Windows NT 3.1 is designed around networks; two newly introduced functions, Remote Procedure Call (RPC) and Network DDE , an extension of Dynamic Data Exchange (DDE), facilitate the access and data exchange between processes running on different computers inside a network. [ 33 ] The operating system is designed to combine certain elements of a monolithic kernel and a microkernel; [ 8 ] : 20 nowadays this is most often referred to as a hybrid kernel . [ 34 ] The hardware abstraction layer represents the lowermost layer and isolates the operating system from the underlying hardware to make it easy to port the operating system to other platforms. [ 8 ] : 30 The kernel running atop only has very basic functions like interrupt management and processor synchronization. All other functions of the operating system core are handled by modules [ 8 ] : 20 which operate independently from one another and can be swapped without affecting the rest of the operating system. [ 8 ] : 28 Positioned above the operating system core are the subsystems. There are two types of subsystems: one are the integral subsystems , which perform important operating system functions. One such subsystem is the security subsystem, which handles the logon process and monitors the security of the system. The other type of subsystem is the environment subsystem , which exposes the operating system functions to applications via application programming interfaces . [ 8 ] : 27 The base subsystem is the 32-bit subsystem which runs 32-bit applications written for Windows NT. Windows NT applications can only run on one platform, and must be recompiled for every platform. The 32-bit subsystem also contains all output functions, including the Graphics Device Interface (GDI), [ 35 ] so all other subsystems have to call the 32-bit subsystem to be able to output text or graphics. [ 8 ] : 33 Other subsystems contained in Windows NT 3.1 are the POSIX subsystem, which supports POSIX-compatible applications built for Windows NT, and, in the x86 version only, the OS/2 subsystem, which allows command-line based OS/2 1.x applications to run. [ 35 ] The Virtual DOS Machine (VDM) is sometimes also viewed as a subsystem, but is, strictly speaking, a normal 32-bit Windows application. It manages applications originally built for DOS. Built on top is Windows on Windows (WoW), which allows applications built for 16-bit Windows operating systems like Windows 3.1 to run. On x86 computers, the virtual DOS machine uses the virtual 8086 mode to run DOS applications directly, [ 35 ] on RISC computers, an emulator licensed from Insignia Solutions is used which emulates a 80286 processor. However, not all DOS and 16-bit Windows applications can be run on Windows NT 3.1 due to various limitations, [ 36 ] one of them being the inability of applications to directly access the hardware. As well, VxD files sometimes needed by applications cannot be used with Windows NT 3.1. [ 37 ] While pure DOS applications are run in separate memory spaces, 16-bit Windows applications have to share one memory space. While this is done due to compatibility reasons with applications which depend on this ability, like Schedule+ and Microsoft Mail , it also means that 16-bit Windows applications only run in cooperative multitasking . A faulty 16-bit Windows application is in this way able to cause all other 16-bit Windows applications (but not Windows NT itself) to crash. [ 35 ] Windows NT 3.1 provides a boot manager called NTLDR which is loaded during the startup process of the operating system on x86-based computers. It allows a multiboot setup of multiple instances of Windows NT 3.1, as well as MS-DOS and OS/2 1.x. [ 38 ] NTLDR is not used for the RISC versions because the RISC computers' firmware provides their own boot manager. [ 39 ] Every user has to log on to the computer after Windows NT 3.1 is booted up by pressing the key combination Ctrl+Alt+Del and entering the user name and password. All users have their own user account , and user-specific settings like the Program Manager groups are stored separately for every user. Users can be assigned specific rights, like the right to change the system time or the right to shut down the computer. To facilitate management of user accounts, it is also possible to group multiple user accounts and assign rights to groups of users. [ 35 ] Windows NT 3.1 introduced the new NTFS file system. This new file system is more robust against hardware failures [ 8 ] : 10 and allows assignment of read and write rights to users or groups on the file system level. [ 35 ] NTFS supports long file names [ 35 ] and has features to accommodate POSIX applications like hard links . [ 8 ] : 39 For compatibility reasons, Windows NT 3.1 also supports FAT16 as well as OS/2's file system HPFS , [ 35 ] but does not support long file names on FAT file system ( VFAT ). This was added in Windows NT 3.5. Designed as a networking operating system, Windows NT 3.1 supports multiple network protocols . Besides IPX/SPX and NetBEUI , the TCP/IP protocol is supported allowing access to the Internet. [ 35 ] Similar to Windows for Workgroups , files and printers can be shared and the access rights and configuration of these resources can be edited over the network. When a network printer is installed, the required drivers are automatically transferred over the network, removing the need to manually install the drivers for every computer. [ 35 ] The Remote Access Service (RAS) allows a client from outside the network to connect to the network using a modem , ISDN or X.25 and access its resources. While the workstation allows one RAS connection at a time, the server supports 64. [ 35 ] Windows NT 3.1 supports the then-new Unicode standard, a character set which allows multiple languages to be displayed. This facilitates localization of the operating system. [ 40 ] All strings, as well as file and folder names, are internally processed in Unicode, [ 8 ] : 43 but the included programs, like the File Manager , are not Unicode aware, so folders containing Unicode characters cannot be accessed. [ 41 ] For demonstration purposes, a Unicode typeface called Lucida Sans Unicode is shipped with Windows NT 3.1 [ 42 ] even though it is not installed by default. The previous code pages are still supported for compatibility purposes. [ 40 ] The Windows registry , introduced with Windows 3.1, is a central, hierarchical configuration database [ 35 ] designed to allow configuration of computers over the network [ 6 ] : 251 and to replace the commonly-used text-based configuration files, like INI files , AUTOEXEC.BAT and CONFIG.SYS . [ 8 ] : 327 Using the undocumented registry editor, the Windows registry can be viewed and edited by the user. [ 35 ] The Advanced Server is designed to manage the workstation computers. [ 35 ] It can function as a Domain controller , where all users and groups as well as their rights are stored. This way, a user can log on from any computer in the network, and users can be managed centrally on the server. Trust relationships can be built to other domains to be able to exchange data cross-domain. [ 35 ] Using the replication service, files like logon scripts can be synchronized across all computers on the network. The Advanced Server supports the AppleTalk protocol to allow connections to Macintosh computers. [ 35 ] Hard drives can be combined to RAIDs in Windows NT 3.1 Advanced Server, the supported configurations are RAID 0, RAID 1 and RAID 5. Windows NT 3.1, for the most part, comes with 32-bit versions of the components featured in Windows 3.1 and Windows for Workgroups. However, it also included applications specifically aimed at the needs of Windows NT, like the User Manager, the Performance Monitor , the Disk Administrator, the Event Viewer and the Backup application. The Advanced Server contained further, server-specific administration tools. Because Windows NT 3.1 is not DOS-based, a new 32-bit command-line processor, called CMD.EXE was included which was compatible with MS-DOS 5.0. [ 35 ] For compatibility reasons, Windows NT 3.1 shipped with a few 16-bit applications, like Microsoft Write or EDLIN . [ 43 ] Windows NT 3.1, being an all-new operating system for which no previous MS-DOS based drivers could be used, includes a wealth of drivers for various common components and peripherals. [ 36 ] This includes common SCSI devices like hard drives, CD-ROM drives, tape drives and image scanners , [ 44 ] as well as ISA devices like graphics cards, sound cards and network cards. The EISA bus, is supported by Windows NT 3.1. The PCI bus , however, is not supported by kernel, but supported by third-party drivers. [ 45 ] Windows NT 3.1 supports an uninterruptible power supply . [ 8 ] : 328 Windows NT 3.1 could be installed either by using the CD-ROM and a provided boot disk , or by utilizing a set of twenty-two 3.5" floppies (twenty-three floppies for Advanced Server ). Windows NT 3.1 could also be installed over the network. [ 35 ] A coupon was included that made it possible to order a set of twenty-seven 5.25" floppies (or twenty-eight floppies for Advanced Server ). [ 46 ] Compared to the floppies, the CD-ROM contained additional drivers and applications. Windows NT 3.1 does not support ATAPI CD-ROMs. Windows NT 3.1 supports multiple platforms: Aside from the x86 architecture, it runs on computers with DEC Alpha or MIPS ( R4000 and R4400 ) processors. [ 47 ] Minimum system requirements on x86 systems include a 25 MHz 80386 processor, at least 12 megabytes of memory, 75 megabytes of hard drive space, and a VGA graphics card. RISC systems require 16 megabytes of memory, 92 megabytes of hard drive space, and a CD-ROM drive. [ 48 ] The Advanced Server edition requires an 80386 processor with 16 megabytes of memory and 90 megabytes of hard drive space. On RISC systems, 110 megabytes of hard drive space is needed. [ 49 ] Windows NT 3.1 supports dual processor systems, while the Advanced Server edition supports up to four processors. Due to an error in the processor detection routine, Windows NT 3.1 cannot be installed on Pentium II or newer processors. Microsoft never fixed the problem, but unofficial patches are available. [ 48 ] Windows NT 3.1 sold about 300,000 copies in its first year. [ 50 ] The hardware requirements were deemed to be very high at that time; the recommended system requirements of a 486 processor with 16 megabytes of memory were well above the average computer's configuration, [ 36 ] and the operating system turned out to be too slow to use. [ 51 ] 32-bit applications which could have used the capabilities of Windows NT 3.1 were scarce, so users had to resort to the old 16-bit applications; however, these ran slower than on Windows 3.1. Estimates in November 1993 counted only 150 Windows NT applications. [ 52 ] Common types of software, like office suites , were not available for Windows NT 3.1. [ 36 ] During the development of the operating system, the API calls were changed so 32-bit applications built on the 1992 pre-release version of Windows NT 3.1 could not be run on the final version. This affected software such as Microsoft Visual C++ 1.0 and Microsoft Fortran PowerStation. [ 53 ] RISC systems with Windows NT 3.1 had an even bigger disadvantage: even though they were more powerful than x86 systems, [ 33 ] almost no 32-bit applications or drivers were ported to these platforms. [ 50 ] 16-bit applications ran much slower under RISC systems because of the 80286 emulation compared to x86 systems which could run 16-bit applications natively, [ 33 ] and DOS and 16-bit applications which depended on 386 calls could not be run at all on RISC systems. However, not all reception was negative; the multitasking capabilities of the operating system were rated positively, especially compared to Windows 3.1. [ 35 ] Compared to the size of the operating system, the installation turned out to be very easy, even though installing from floppies was a very time-consuming task. [ 54 ] The Advanced Server , intended to be the successor to the unsuccessful LAN Manager product, was technically much superior to its predecessor, and only failed to gain success because it shared the same problems with its workstation pendant, such as the low performance running 16-bit applications. [ 55 ] The Advanced Server provided a financial advantage for large networks because its price was not dependent on the number of clients, unlike its competitor Novell NetWare. [ 49 ] With Windows NT, Microsoft entered a market it could not previously address and which was mostly dominated by Unix, Novell NetWare and OS/2. [ 56 ] A test performed by the InfoWorld magazine in November 1993, where the networking capabilities of several operating systems were tested, showed that Windows NT 3.1 was seriously lacking in inter-client communication: it could only connect to its own server via NetBEUI ; attempts to connect to Unix, NetWare and OS/2 all failed because no client software was available. For the Advanced Server , only their own client, the Macintosh and, if only limited, OS/2 were able to connect to the server. [ 57 ] Even though the operating system's actual success was only moderate, it had a huge lasting impact. Developers of Unix derivations for the first time strived to standardize their operating systems, and Novell was so concerned about its market share that it bought a Unix vendor. [ 6 ] : 303 Manufacturers of microprocessors hoped to use the portability of the new operating system to increase their own sales, [ 6 ] : 303 and thus ports of Windows NT were announced for various platforms, like the Sun SPARC architecture [ 58 ] and the Clipper architecture . [ 59 ] It was recognized that Windows NT would dominate the desktop market as soon as the hardware became powerful enough to run the operating system at an acceptable speed. [ 60 ] Eight years later, Microsoft would unify the consumer-oriented Windows line (which had remained MS-DOS based) with the NT line with the October 2001 release of Windows XP —the first consumer-oriented version of Windows to use the NT architecture. [ 61 ]	https://en.wikipedia.org/wiki/Windows_NT_3.1
A windpost is a structural item used in the design and construction of masonry walls to increase lateral wall stability and protect them against damage from horizontal forces imposed by wind pressure, crowd or handrail loads. [ 1 ] They are normally constructed from mild steel channel sections, supported at the head and the foot between floor slab levels and/or the principal steelwork sections forming the structural frame of the building. In cavity walls, the windpost will typically be fixed into the inner and outer leafs of the wall by specialist fixings and fastenings at regular intervals along its length. The windposts will be spaced along the walls of the building at regular intervals as calculated by the engineer to suit the required loadings. In most cases a windpost is a large and very unwieldy element that can often weigh in excess of 400 kg. The manufacture and delivery of both steel and concrete windposts has a significant carbon footprint and once delivered to site, their storage requires large areas to be set aside. The procurement of windposts, including the design process, often requires a lead time of four to five weeks. The length and weight of windposts makes them particularly difficult to manoeuvre into position in confined spaces. When installed as part of an internal wall, significant health and safety risks exist for the installers in lifting the windpost to its vertical position. There is no recognised mechanical lifting method to safely erect windposts. The properties of steel windposts have inherent fire integrity, acoustic, air tightness and thermal movement issues, all of which require additional measures to achieve specification compliance at extra cost. Design Methods and Alternatives Windposts are designed to span vertically, floor to floor and provide lateral support for masonry wall panels. The windposts will usually be restrained by the brickwork and designed as simply supported beams . As an alternative to steel windposts, when the primary structure is composed of reinforced concrete, secondary structures are cast in situ to provide lateral support to masonry panels. Traditional design methods are often not optimised for the design of masonry panels with openings, and therefore windposts can be over specified on walls where the design capacity may not be utilised. Using alternative design methods such as advanced yield line analysis, the specification of wind posts within masonry wall panels can often be optimised and often omitted. These calculations can be typically carried out by structural engineering software packages such as MasterSeries . [ 2 ] [ 3 ] Recently, a new innovative technique of reinforcing blockwork walls has been developed by Wembley Innovation Ltd and used in many Crossrail projects in the UK. It consists of using uniquely designed hollow blocks to allow the construction of reinforced concrete beams (Wi Beams) and columns (Wi Columns) within the blockwork construction, which eliminate the need for traditional windposts or lintels. This new technique maximises masonry wall strength without thickening the wall or harming its appearance and allows the architects to design and create uninterrupted blockwork panels with flexible detailing options, whilst retaining the performance characteristics of traditional masonry such as fire integrity, acoustic performance and air permeability . This modular approach also provides the adaptability for contractors to make late changes to construction without affecting the build programme and creates seamless walls which do not require any fire protection. [ 4 ]	https://en.wikipedia.org/wiki/Windpost
In agriculture , windrow composting is the production of compost by piling organic matter or biodegradable waste , such as animal manure and crop residues, in long rows – windrow . As the process is aerobic, it is also known as Open Windrow Composting (OWC) or Open Air Windrow Composting (OAWC). [ 1 ] This method is suited to producing large volumes of compost. These rows are generally turned to improve porosity and oxygen content, mix in or remove moisture, and redistribute cooler and hotter portions of the pile. Windrow composting is a commonly used farm scale composting method. Composting process control parameters include the initial ratios of carbon and nitrogen rich materials, the amount of bulking agent added to assure air porosity, the pile size, moisture content, and turning frequency. The temperature of the windrows must be measured and logged constantly to determine the optimum time to turn them for quicker compost production. Compost windrow turners were developed to produce compost on a large scale by Fletcher Sims Jr. of Canyon, Texas. [ 2 ] They are traditionally a large machine that straddles a windrow of 4 feet (1.2 meters) or more high, by as much as 12 feet (3.7 meters) across. Although smaller machines exist for small windrows, most operations use large machines for volume production. Turners drive through the windrow at a slow rate of forward movement. They have a steel drum with paddles that are rapidly turning. As the turner moves through the windrow, fresh air ( oxygen ) is injected into the compost by the drum/paddle assembly, and waste gases produced by bacterial decomposition are vented. The oxygen feeds the aerobic bacteria and thus speeds the composting process. To properly use a compost windrow turner, it is ideal to compost on a hard surfaced pad. Heavy-duty compost windrow turners allow the user to obtain optimum results with the aerobic hot composting process. By using four wheel drive or tracks the windrow turner is capable of turning compost in windrows located in remote locations. With a self-trailering option this allows the compost windrow turner to convert itself into a trailer to be pulled by a semi-truck tractor . These two options combined allow the compost windrow turner to be easily hauled anywhere and to work compost windrows in muddy and wet locations. Molasses-based distilleries all over the world generate large amount of effluent termed as spent wash or vinasse . For each liter of alcohol produced, around 8 liters of effluent is generated. This effluent has chemical oxygen demand (COD) of 1,50,000 PPM and biochemical oxygen demand (BOD) of 60,000 PPM and even more. This effluent needs to be treated and the only effective method for conclusive disposal is by composting. Sugar factories generate pressmud / cachaza during the process and the same has about 30% fibers as carbon and has large amounts of water. This pressmud is dumped on prepared land in the form of 100 meters long windrows of 3 meters x 1.5 meters and spent wash is sprayed on the windrow while the windrow is being turned. These machines help consume spent wash of about 2.5 times of the volume of the pressmud, which means that 100 meters of windrow accommodates about 166 MT of pressmud and uses about 415 m³ of spent wash in 50 days. Microbial Culture (organic solution) TRIO COM-CULT is used about 1 kg per MT of pressmud for fast de-composing of the spent wash. Hundreds of thousands of square meters of spent wash is being composted all over the world in countries like India, Colombia, Brazil, Thailand, Indonesia, South Africa etc. The compost yard has to be prepared in such a way that the land is impervious and does not allow the liquid effluent to pass down into the earth. The compost thus generated is of excellent quality and is rich in nutrients.	https://en.wikipedia.org/wiki/Windrow_composting
In forestry , windthrow refers to trees uprooted by wind . Breakage of the tree bole (trunk) instead of uprooting is called windsnap . [ 1 ] Blowdown refers to both windthrow and windsnap. Windthrow is common in all forested parts of the world that experience storms or high wind speeds. The risk of windthrow to a tree is related to the tree's size (height and diameter), the 'sail area' presented by its crown, the anchorage provided by its roots, its exposure to the wind, and the local wind climate. A common way of quantifying the risk of windthrow to a forest area is to model the probability or 'return time' of a wind speed that would damage those trees at that location. Another potential method is the detection of scattered windthrow based on satellite images. [ 2 ] Tree senescence can also be a factor, where multiple factors contributing to the declining health of a tree reduce its anchorage and therefore increase its susceptibility to windthrow. The resulting damage can be a significant factor in the development of a forest. Windthrow can also increase following logging , especially in young forests managed specifically for timber . The removal of trees at a forest's edge increases the exposure of the remaining trees to the wind. Trees that grow adjacent to lakes or other natural forest edges, or in exposed situations such as hill sides, develop greater rooting strength through growth feedback with wind movement, i.e. 'adaptive' or 'acclimative' growth. If a tree does not experience much wind movement during the stem exclusion phase of stand succession , it is not likely to develop a resistance to wind. Thus, when a fully or partially developed stand is bisected by a new road or by a clearcut , the trees on the new edge are less supported by neighbouring trees than they were and may not be capable of withstanding the higher forces which they now experience. Trees with heavy growths of ivy , wisteria , or kudzu are already stressed and may be more susceptible to windthrow, as the additional foliage increases the tree's sail area. Trees with decayed trunk, fungus -induced cankers , and borer damages are more susceptible to windsnap. [ 1 ] Young trees (less than 100 years old) can snap when pushed by wind gusts, while older trees usually do not snap but are uprooted. [ 3 ] Windthrow disturbance generates a variety of unique ecological resources on which certain forest processes are highly dependent. Windthrow can be considered a cataclysmic abiotic factor that can generate an entire new chain of seral plant succession in a given area. [ 4 ] Windthrow can also be considered to act as a rejuvenating process whereby regeneration is made possible with new resource availability. Severe uprooting opens bare patches of mineral soil that can act as seed sinks. These patches have been shown, in the Pacific Northwest of the United States, to have higher biodiversity than the surrounding forest floor. Additionally, the gap created in the forest canopy when windthrow occurs yields an increase in light, moisture, and nutrient availability in near proximity to the disturbance. Toppled trees have the potential to become nurse logs , nurturing habitats for other forest organisms. Tree throws contribute to bedrock weathering and soil formation . In thin soils, fresh bedrock fragments are a large proportion of the upturned rootwad, but trees are sparse, so rates of weathering are low; in intermediate-depth soils less rock is upturned, but trees are more common, so weathering reaches a maximum; in soils deeper than the depth of roots, no bedrock is upturned, and weathering is slow. [ 3 ] The advent of trees roughly 370 million years ago led to dramatic ecosystem changes, as before then bedrock weathering was too slow to maintain thick soils in hilly terrain. [ 3 ]	https://en.wikipedia.org/wiki/Windthrow
In geography and seamanship , windward ( / ˈ w ɪ n d w ər d , ˈ w ɪ n ər d / ) and leeward ( / ˈ l iː w ər d , ˈ lj uː ər d / ) are directions relative to the wind . Windward is upwind from the point of reference, i.e., towards the direction from which the wind is coming; leeward is downwind from the point of reference, i.e., along the direction towards which the wind is going. The side of a ship that is towards the leeward is its "lee side". If the vessel is heeling under the pressure of crosswind , the lee side will be the "lower side". During the Age of Sail , the term weather was used as a synonym for windward in some contexts, as in the weather gage . Since it captures rainfall , the windward side of a mountain tends to be wetter than the leeward side it blocks. The drier leeward area is said to be in a rain shadow . The term "windward" has roots in both Low German and Old English. The word "lee", which means a place without wind, comes from the Old Norse "hle" for "cover" and has been used in marine navigation in Germany since medieval times. The word "wind," meaning "air in motion," comes from Proto-Germanic winda- and has evolved over time, with pronunciation changes influenced by similar words like "windy." The word "wind" has been associated with emptiness and vanity since the late 13th century. Additionally, "wind" has been used figuratively in phrases like "which way the wind blows" to indicate the current state of affairs. The suffix "-ward," meaning "toward," is an adverbial suffix in Old English derived from Proto-Germanic werda-, which itself comes from the PIE root *wer- meaning "to turn, bend." The original notion of "-ward" is "turned toward." [ 1 ] [ 2 ] Windward and leeward directions (and the points of sail they create) are important factors to consider in such wind-powered or wind-impacted activities as sailing , wind-surfing , gliding , hang-gliding , and parachuting . Other terms with broadly the same meaning are widely used, particularly upwind and downwind . [ 3 ] Among sailing craft, the windward vessel is normally the more maneuverable. For this reason, rule 12 of the International Regulations for Preventing Collisions at Sea , applying to sailing vessels, stipulates that where two are sailing in similar directions in relation to the wind, the windward vessel gives way to the leeward vessel. [ 4 ] In naval warfare during the Age of Sail , a vessel always sought to use the wind to its advantage, maneuvering if possible to attack from windward. This was particularly important for less maneuverable square-rigged warships, which had limited ability to sail upwind, and sought to "hold the weather gage " entering battle. [ 5 ] This was particularly important once artillery was introduced to naval warfare. Ships heel away from the wind, so the leeward vessel would expose more of her topsides to shot, in extreme cases even part of her bottom. [ 6 ] The terms windward and leeward are used in reference both to sides (and climates [ 7 ] ) of individual islands and relative island locations in an archipelago . The windward side of an island is subject to the prevailing wind , and is thus the wetter (see orographic precipitation ). The leeward side is the side distant from or physically in the lee of the prevailing wind, and typically the drier. In an archipelago windward islands are upwind and leeward islands are downwind of the prevailing winds, such as the trade winds of the Atlantic and Pacific oceans.	https://en.wikipedia.org/wiki/Windward_and_leeward
A Windwatt /'vɪntvat/ is a mudflat exposed as a result of wind action on water. They occur especially in the Western Pomerania Lagoon Area National Park on Germany's Baltic Sea coast. The term is German. [ 1 ] Unlike the Wadden Sea along Europe's North Sea coast, the shallow water zones of the Western Pomerania Lagoon Area National Park are largely unaffected by oceanic tides . When there are strong winds in a certain direction, however, water is driven out of the lagoons (the so-called bodden ) into the Baltic Sea , so that several particularly shallow areas of mud become exposed and dry out. The water flows back when the wind turns again. [ 1 ] These Windwatten are a major source of food for migrating birds in the autumn . For the Crane , which cross Western Pomeranian bodden country during migration, the Windwatten are one of the most important resting areas in Western Europe.	https://en.wikipedia.org/wiki/Windwatt
In the wine/water mixing problem , one starts with two barrels , one holding wine and the other an equal volume of water . A cup of wine is taken from the wine barrel and added to the water. A cup of the wine/water mixture is then returned to the wine barrel, so that the volumes in the barrels are again equal. The question is then posed—which of the two mixtures is purer? [ 1 ] The answer is that the mixtures will be of equal purity. The solution still applies no matter how many cups of any sizes and compositions are exchanged, or how little or much stirring at any point in time is done to any barrel, as long as at the end each barrel has the same amount of liquid. The problem can be solved with logic and without resorting to computation . It is not necessary to state the volumes of wine and water, as long as they are equal. The volume of the cup is irrelevant, as is any stirring of the mixtures. [ 2 ] Conservation of substance implies that the volume of wine in the barrel holding mostly water has to be equal to the volume of water in the barrel holding mostly wine. [ 2 ] The mixtures can be visualised as separated into their water and wine components: Move V 1 of wine right Move V 1 of mixture (comprising V 2 wine and V 1 – V 2 water) left = ⁠ V 0 – V 1 + V 2 / V 0 ⁠ = ⁠ V 0 – V 1 + V 2 / V 0 ⁠ To help in grasping this, the wine and water may be represented by, say, 100 red and 100 white marbles , respectively. If 25, say, red marbles are mixed in with the white marbles, and 25 marbles of any color are returned to the red container, then there will again be 100 marbles in each container. If there are now x white marbles in the red container, then there must be x red marbles in the white container. The mixtures will therefore be of equal purity. An example is shown below. Move 25 (all red) right Move 25 (20 white, 5 red) left This puzzle was mentioned by W. W. Rouse Ball in the third, 1896, edition of his book Mathematical Recreations And Problems Of Past And Present Times , and is said to have been a favorite problem of Lewis Carroll . [ 3 ] [ 4 ]	https://en.wikipedia.org/wiki/Wine/water_mixing_problem
Wine [ a ] is a free and open-source compatibility layer to allow application software and computer games developed for Microsoft Windows to run on Unix-like operating systems . Developers can compile Windows applications against WineLib to help port them to Unix-like systems. Wine is predominantly written using black-box testing reverse engineering , to avoid copyright issues. No code emulation or virtualization occurs. Wine is primarily developed for Linux and macOS . In a 2007 survey by desktoplinux.com of 38,500 Linux desktop users, 31.5% of respondents reported using Wine to run Windows applications. [ 9 ] This plurality was larger than all x86 virtualization programs combined, and larger than the 27.9% who reported not running Windows applications. [ 10 ] Bob Amstadt, the initial project leader, and Eric Youngdale started the Wine project in 1993 as a way to run Windows applications on Linux . It was inspired by two Sun Microsystems products, Wabi for the Solaris operating system, and the Public Windows Interface , [ 11 ] which was an attempt to get the Windows API fully reimplemented in the public domain as an ISO standard but rejected due to pressure from Microsoft in 1996. [ 12 ] Wine originally targeted 16-bit applications for Windows 3.x , but as of 2010 [update] focuses on 32-bit and 64-bit versions which have become the standard on newer operating systems. The project originated in discussions on Usenet in comp.os.linux in June 1993. [ 13 ] Alexandre Julliard has led the project since 1994. The project has proven time-consuming and difficult for the developers, mostly because of incomplete and incorrect documentation of the Windows API. While Microsoft extensively documents most Win32 functions , some areas such as file formats and protocols have no public, complete specification available from Microsoft. Windows also includes undocumented low-level functions, undocumented behavior and obscure bugs that Wine must duplicate precisely in order to allow some applications to work properly. [ 14 ] Consequently, the Wine team has reverse-engineered many function calls and file formats in such areas as thunking . [ citation needed ] The Wine project originally released Wine under the same MIT License as the X Window System, but owing to concern about proprietary versions of Wine not contributing their changes back to the core project, [ 15 ] work as of March 2002 has used the LGPL for its licensing. [ 16 ] Wine officially entered beta with version 0.9 on 25 October 2005. [ 17 ] Version 1.0 was released on 17 June 2008, [ 18 ] after 15 years of development. Version 1.2 was released on 16 July 2010, [ 19 ] version 1.4 on 7 March 2012, [ 20 ] version 1.6 on 18 July 2013, [ 21 ] version 1.8 on 19 December 2015 [ 22 ] and version 9.0 on 16 January 2024. [ 23 ] Development versions are released roughly every two weeks. Wine-staging is an independently maintained set of aggressive patches not deemed ready by WineHQ developers for merging into the Wine repository, but still considered useful by the wine-compholio fork . It mainly covers experimental functions and bug fixes. Since January 2017, patches in wine-staging begins to be actively merged into the WineHQ upstream as wine-compholio transferred the project to Alistair Leslie-Hughes, a key WineHQ developer. As of 2019 [update] , WineHQ also provides pre-built versions of wine-staging. [ 24 ] The main corporate sponsor of Wine is CodeWeavers , which employs Julliard and many other Wine developers to work on Wine and on CrossOver , CodeWeavers' supported version of Wine. CrossOver includes some application-specific tweaks not considered suitable for the upstream version, as well as some additional proprietary components. [ 25 ] Canadian software developer Corel for a time assisted the project, chiefly by employing Julliard and others to work on it. Corel had an interest in porting WordPerfect Office , its office suite , to Linux (especially Corel Linux ). Corel later cancelled all Linux-related projects after Microsoft made major investments in Corel, stopping their Wine effort. [ 26 ] Other corporate sponsors include Google , which hired CodeWeavers to fix Wine so Picasa ran well enough to be ported directly to Linux using the same binary as on Windows; Google later paid for improvements to Wine's support for Adobe Photoshop CS2 . [ 27 ] Wine is also a regular beneficiary of Google's Summer of Code program. [ 28 ] Valve works with CodeWeavers to develop Proton , a Wine-based compatibility layer for Microsoft Windows games to run on Linux -based operating systems. Proton includes several patches that upstream Wine does not accept for various reasons, such as Linux-specific implementations of Win32 functions. The goal of Wine is to implement the Windows APIs fully or partially that are required by programs that the users of Wine wish to run on top of a Unix-like system. The programming interface of Microsoft Windows consists largely of dynamic-link libraries (DLLs). These contain a huge number of wrapper sub-routines for the system calls of the kernel, the NTOS kernel-mode program (ntoskrnl.exe). A typical Windows program calls some Windows DLLs, which in turn calls user-mode gdi/user32 libraries, which in turn uses the kernel32.dll (win32 subsystem) responsible for dealing with the kernel through system calls. The system-call layer is considered private to Microsoft programmers as documentation is not publicly available, and published interfaces all rely on subsystems running on top of the kernel. Besides these, there are a number of programming interfaces implemented as services that run as separate processes. Applications communicate with user-mode services through RPCs. [ 29 ] Wine implements the Windows application binary interface (ABI) entirely in user space , rather than as a kernel module . Wine mostly mirrors the hierarchy, with services normally provided by the kernel in Windows [ 30 ] instead provided by a daemon known as the wineserver, whose task is to implement basic Windows functionality, as well as integration with the X Window System , and translation of signals into native Windows exceptions. Although wineserver implements some aspects of the Windows kernel , it is not possible to use native Windows drivers with it, due to Wine's underlying architecture. [ 29 ] Wine allows for loading both Windows DLLs and Unix shared objects for its Windows programs. Its built-in implementation of the most basic Windows DLLs , namely NTDLL , KERNEL32 , GDI32 , and USER32 , uses the shared object method because they must use functions in the host operating system as well. Higher-level libraries, such as WineD3D, are free to use the DLL format. In many cases users can choose to load a DLL from Windows instead of the one implemented by Wine. Doing so can provide functionalities not yet implemented by Wine, but may also cause malfunctions if it relies on something else not present in Wine. [ 29 ] Wine tracks its state of implementation through automated unit testing done at every git commit. [ 31 ] While most office software does not make use of complex GPU-accelerated graphics APIs, computer games do. To run these games properly, Wine would have to forward the drawing instructions to the host OS, and even translate them to something the host can understand. DirectX is a collection of Microsoft APIs for rendering, audio and input. As of 2019, Wine 4.0 contains a DirectX 12 implementation for Vulkan API , and DirectX 11.2 for OpenGL. [ 32 ] Direct2D support has been updated to Direct2D 1.2. [ 32 ] Wine 4.0 also allows Wine to run Vulkan applications by handing draw commands to the host OS, or in the case of macOS, by translating them into the Metal API by MoltenVK . [ 32 ] Much of Wine's DirectX effort goes into building WineD3D, a translation layer from Direct3D and DirectDraw API calls into OpenGL . As of 2019, this component supports up to DirectX 11. [ 32 ] As of 12 December 2016, Wine is good enough to run Overwatch with D3D11. [ 35 ] Besides being used in Wine, WineD3D DLLs have also been used on Windows itself, allowing for older GPUs to run games using newer DirectX versions and for old DDraw-based games to render correctly. [ 36 ] Some work is ongoing to move the Direct3D backend to Vulkan API. Direct3D 12 support in 4.0 is provided by a "vkd3d" subproject, [ 32 ] and WineD3D has in 2019 been experimentally ported to use the Vulkan API. [ 37 ] Another implementation, DXVK , translates Direct3D 8, 9, 10, and 11 calls using Vulkan as well and is a separate project. [ 38 ] Wine, when patched, can alternatively run Direct3D 9 API commands directly via a free and open-source Gallium3D State Tracker (aka Gallium3D GPU driver) without translation into OpenGL API calls. In this case, the Gallium3D layer allows a direct pass-through of DX9 drawing commands which results in performance improvements of up to a factor of 2. [ 39 ] As of 2020, the project is named Gallium.Nine. It is available now as a separate standalone package and no longer needs a patched Wine version. [ 40 ] Wine is usually invoked from the command-line interpreter: wine program.exe . [ 41 ] There is the utility winecfg that starts a graphical user interface with controls for adjusting basic options. [ 42 ] It is a GUI configuration utility included with Wine. Winecfg makes configuring Wine easier by making it unnecessary to edit the registry directly, although, if needed, this can be done with the included registry editor (similar to Windows regedit ). Some applications require more tweaking than simply installing the application in order to work properly, such as manually configuring Wine to use certain Windows DLLs . The Wine project does not integrate such workarounds into the Wine codebase, instead preferring to focus solely on improving Wine's implementation of the Windows API . While this approach focuses Wine development on long-term compatibility, it makes it difficult for users to run applications that require workarounds. Consequently, many third-party applications have been created to ease the use of those applications that do not work out of the box within Wine itself. The Wine wiki maintains a page of current and obsolete third-party applications. [ 43 ] The developers of the Direct3D portions of Wine have continued to implement new features such as pixel shaders to increase game support. [ 55 ] Wine can also use native DLLs directly, thus increasing functionality, but then a license for Windows is needed unless the DLLs were distributed with the application itself. Wine also includes its own open-source implementations of several Windows programs, such as Notepad , WordPad , Control Panel , Internet Explorer , and Windows Explorer . [ 56 ] The Wine Application Database (AppDB) is a community-maintained on-line database about which Windows programs works with Wine and how well they work. Wine ensures good backward compatibility with legacy Windows applications, including those written for Windows 3.1x . [ 57 ] Wine can mimic different Windows versions required for some programs, going as far back as Windows 2.0 . [ 58 ] However, Windows 1.x and Windows 2.x support was removed from Wine development version 1.3.12. If DOSBox is installed on the system [ citation needed ] (see below on MS-DOS ), Wine development version 1.3.12 and later nevertheless show the "Windows 2.0" option for the Windows version to mimic, but Wine still will not run most Windows 2.0 programs because MS-DOS and Windows functions are not currently integrated. Backward compatibility in Wine is generally superior to that of Windows, as newer versions of Windows can force users to upgrade legacy Windows applications, and may break unsupported software forever as there is nobody adjusting the program for the changes in the operating system. In many cases, Wine can offer better legacy support than newer versions of Windows with "Compatibility Mode". Wine can run 16-bit Windows programs ( Win16 ) on a 64-bit operating system, which uses an x86-64 (64-bit) CPU, [ 59 ] a functionality not found in 64-bit versions of Microsoft Windows. [ 60 ] [ 61 ] WineVDM allows 16-bit Windows applications to run on 64-bit versions of Windows. [ 62 ] Wine partially supports Windows console applications , and the user can choose which backend to use to manage the console (choices include raw streams, curses , and user32 ). [ 63 ] When using the raw streams or curses backends, Windows applications will run in a Unix terminal. Preliminary support for 64-bit Windows applications was added to Wine 1.1.10, in December 2008. [ 64 ] As of April 2019 [update] , the support is considered stable. The two versions of Wine are built separately, and as a result only building wine64 produces an environment only capable of running x86-64 applications. [ 65 ] As of April 2019 [update] , Wine has stable support for a WoW64 build, which allows both 32-bit and 64-bit Windows applications to run inside the same Wine instance. To perform such a build, one must first build the 64-bit version, and then build the 32-bit version referencing the 64-bit version. Just like Microsoft's WoW64, the 32-bit build process will add parts necessary for handling 32-bit programs to the 64-bit build. [ 65 ] This functionality is seen from at least 2010. [ 66 ] Early versions of Microsoft Windows run on top of MS-DOS , and Windows programs may depend on MS-DOS programs to be usable. Wine does not have good support for MS-DOS, but starting with development version 1.3.12, Wine tries running MS-DOS programs in DOSBox if DOSBox is available on the system. [ 67 ] However, due to a bug, current versions [ needs update ] of Wine incorrectly identify Windows 1.x and Windows 2.x programs as MS-DOS programs, attempting to run them in DOSBox (which does not work). [ 68 ] Wine provides Winelib, which allows its shared-object implementations of the Windows API to be used as actual libraries for a Unix program. This allows for Windows code to be built into native Unix executables. Since October 2010, Winelib also works on the ARM platform. [ 69 ] Support for Solaris SPARC was dropped in version 1.5.26. Wine provides some support for ARM (as well as ARM64/AArch64) processors and the Windows flavors that run on it. As of April 2019 [update] , Wine can run ARM/Win32 applications intended for unlocked Windows RT devices (but not Windows RT programs). Windows CE support (either x86 or ARM) is missing, [ 70 ] but an unofficial, pre-alpha proof-of-concept version called WineCE allows for some support. [ 71 ] On 3 February 2013 at the FOSDEM talk in Brussels, Alexandre Julliard demonstrated an early demo of Wine running on Google's Android operating system. [ 72 ] Experimental builds of WINE for Android (x86 and ARM) were released in late 2017. It has been routinely updated by the official developers ever since. [ 4 ] The default builds do not implement cross-architecture emulation via QEMU , and as a result ARM versions will only run ARM applications that use the Win32 API. [ 73 ] Wine, by default, uses specialized Windows builds of Gecko and Mono to substitute for Microsoft's Internet Explorer and .NET Framework . Wine has built-in implementations of JScript and VBScript . It is possible to download and run Microsoft's installers for those programs through winetricks or manually. Wine is not known to have good support for most versions of Internet Explorer (IE). Of all the reasonably recent versions, Internet Explorer 8 for Windows XP is the only version that reports a usable rating on Wine's AppDB, out-of-the-box. [ 74 ] However Google Chrome gets a gold rating (as of Wine 5.5-staging), [ 75 ] and Microsoft's IE replacement web browser Edge, is known to be based on that browser (after switching from Microsoft's own rendering engine [ 76 ] ). Winetricks offer auto-installation for Internet Explorer 6 through 8, so these versions can be reasonably expected to work with its built-in workarounds. An alternative for installing Internet Explorer directly is to use the now-defunct IEs4Linux . It is not compatible with the latest versions of Wine, [ 77 ] and the development of IEs4Linux is inactive. The core Wine development aims at a correct implementation of the Windows API as a whole and has sometimes lagged in some areas of compatibility with certain applications. Direct3D, for example, remained unimplemented until 1998, [ 78 ] although newer releases have had an increasingly complete implementation. [ 79 ] CodeWeavers markets CrossOver specifically for running Microsoft Office and other major Windows applications, including some games. CodeWeavers employs Alexandre Julliard to work on Wine and contributes most of its code to the Wine project under the LGPL. CodeWeavers also released a new version called CrossOver Mac for Intel-based Apple Macintosh computers on 10 January 2007. [ 80 ] Unlike upstream wine, CrossOver is notably able to run on the x64-only versions of macOS, [ 81 ] using a technique known as "wine32on64". [ 82 ] As of 2012, CrossOver includes the functionality of both the CrossOver Games and CrossOver Pro lines therefore CrossOver Games and CrossOver Pro are no longer available as single products. [ 83 ] CrossOver Games was optimized for running Windows video games . Unlike CrossOver, it didn't focus on providing the most stable version of Wine. Instead, experimental features are provided to support newer games. [ 84 ] On 21 August 2018, Valve announced a new variation of Wine, named Proton, designed to integrate with the Linux version of the company's Steam software (including Steam installations built into their Linux-based SteamOS operating system and Steam Machine computers). [ 85 ] Valve's goal for Proton is to enable Steam users on Linux to play games which lack a native Linux port (particularly back-catalog games), and ultimately, through integration with Steam as well as improvements to game support relative to mainline Wine, to give users "the same simple plug-and-play experience" that they would get if they were playing the game natively on Linux. [ 85 ] Proton entered public beta immediately upon being announced. [ 85 ] Valve had already been collaborating with CodeWeavers since 2016 to develop improvements to Wine's gaming performance, some of which have been merged to the upstream Wine project. [ 85 ] Some of the specific improvements incorporated into Proton include Vulkan -based Direct3D 9, 10, 11, and 12 implementations via vkd3d , [ 86 ] DXVK , [ 87 ] and D9VK [ 88 ] multi-threaded performance improvements via esync, [ 89 ] improved handling of fullscreen games, and better automatic game controller hardware support. [ 85 ] Proton is fully open-source and available via GitHub. [ 90 ] The Russian company Etersoft has been developing a proprietary version of Wine since 2006. WINE@Etersoft supports popular Russian applications (for example, 1C:Enterprise by 1C Company ). [ 91 ] Other projects using Wine source code include: The Wine project has received a number of technical and philosophical complaints and concerns over the years. Because of Wine's ability to run Windows binary code, concerns have been raised over native Windows viruses and malware affecting Unix-like operating systems [ 111 ] as Wine can run limited malware made for Windows. A 2018 security analysis found that 5 out of 30 malware samples were able to successfully run through Wine, a relatively low rate that nevertheless posed a security risk. [ 112 ] For this reason the developers of Wine recommend never running it as the superuser . [ 113 ] Malware research software such as ZeroWine [ 114 ] runs Wine on Linux in a virtual machine , to keep the malware completely isolated from the host system. An alternative to improve the security without the performance cost of using a virtual machine, is to run Wine in an LXC container, as Anbox software is doing by default with Android . Another security concern is when the implemented specifications are ill-designed and allow for security compromise. Because Wine implements these specifications, it will likely also implement any security vulnerabilities they contain. One instance of this problem was the 2006 Windows Metafile vulnerability , which saw Wine implementing the vulnerable SETABORTPROC escape. [ 115 ] [ 116 ] A common concern about Wine is that its existence means that vendors are less likely to write native Linux, macOS, and BSD applications. As an example of this, it is worth considering IBM's 1994 operating system, OS/2 Warp . [ original research? ] An article describes the weaknesses of OS/2 which killed it, the first one being: OS/2 offered excellent compatibility with DOS and Windows 3.1 applications. No, this is not an error. Many application vendors argued that by developing a DOS or Windows app, they would reach the OS/2 market in addition to DOS/Windows markets and they didn't develop native OS/2 applications. [ 117 ] However, OS/2 had many problems with end user acceptance. Perhaps the most serious was that most computers sold already came with DOS and Windows, and many people didn't bother to evaluate OS/2 on its merits due to already having an operating system. "Bundling" of DOS and Windows and the chilling effect this had on the operating system market frequently came up in United States v. Microsoft Corporation . The Wine project itself responds to the specific complaint of "encouraging" the continued development for the Windows API on one of its wiki pages: For most people there remain a handful of programs locking them in to Windows. It's obvious there will never be a Microsoft Office ported to Linux, however older versions of programs like TurboTax won't be ported either. Similarly, there are tens of thousands of games and internal corporate applications which will never be ported. If you want to use Linux and rely on any legacy Windows application, something like Wine is essential... Wine makes Linux more useful and allows for millions of users to switch who couldn't otherwise. This greatly raises Linux marketshare, drawing more commercial and community developers to Linux. [ 118 ] Also, the Wine Wiki page claims that Wine can help break the chicken-and-egg problem for Linux on the desktop : [ 119 ] This brings us to the chicken and egg issue of Linux on the desktop. Until Linux can provide equivalents for the above applications, its market share on the desktop will stagnate. But until the market share of Linux on the desktop rises, no vendor will develop applications for Linux. How does one break this vicious circle? Again, Wine can provide an answer. By letting users reuse the Windows applications they have invested time and money in, Wine dramatically lowers the barrier that prevents users from switching to Linux. This then makes it possible for Linux to take off on the desktop, which increases its market share in that segment. In turn, this makes it viable for companies to produce Linux versions of their applications, and for new products to come out just for the Linux market. This reasoning could be dismissed easily if Wine was only capable of running Solitaire. However, now it can run Microsoft Office, multimedia applications such as QuickTime and Windows Media Player, and even games such as Max Payne or Unreal Tournament 3. Almost any other complex application can be made to run well given a bit of time. And each time that work is done to add one application to this list, many other applications benefit from this work and become usable too. Have a look at our Application Database to get an idea on what can be run under Wine. The use of Wine for gaming has proved specifically controversial in the Linux community, as some feel it is preventing, or at least hindering, the further growth of native Linux gaming on the platform. [ 120 ] [ 121 ] One quirk however is that Wine is now able to run 16-bit and even certain 32-bit applications and games that do not launch on current 64-bit Windows versions. [ 122 ] This use-case has led to running Wine on Windows itself via Windows Subsystem for Linux or third-party virtual machines , [ citation needed ] as well as encapsulated by means such as BoxedWine [ 123 ] and Otvdm. [ 124 ] Until 2020, Microsoft had not made any public statements about Wine. However, the Windows Update online service will block updates to Microsoft applications running in Wine. On 16 February 2005, Ivan Leo Puoti discovered that Microsoft had started checking the Windows Registry for the Wine configuration key and would block the Windows Update for any component. [ 125 ] As Puoti noted: "It's also the first time Microsoft acknowledges the existence of Wine." In January 2020, Microsoft cited Wine as a positive consequence of being able to reimplement APIs, in its amicus curiae brief for Google LLC v. Oracle America, Inc. [ 126 ] In August 2024, Microsoft donated the Mono Project , a reimplementation of the .NET Framework , to the developers of Wine. [ 127 ]	https://en.wikipedia.org/wiki/Wine_(software)
Winford Lee Lewis (May 29, 1878 – January 20, 1943) [ 1 ] was a US soldier and chemist best known for his rediscovery of the chemical warfare agent lewisite in 1917. He was born in Gridley, California and died in his home in Evanston, Illinois in 1943 following a fall . [ 2 ] Winford Lee Lewis was born at home to George M Lewis and Sarah A Lewis on May 29, 1878, in Gridley, California. He was the youngest of seven children: he had six brothers and one sister. [ 3 ] In 1908 he and his wife Myrlilla C Lewis had a daughter Miriam Lewis. [ 4 ] He attended Stanford University and graduated in 1902. [ 5 ] In 1909, he graduated with a degree in chemistry from the University of Chicago . He became a chemistry professor at Northwestern University until the outbreak of World War I . During the war, he served in the United States Chemical Warfare Service . [ 5 ] It was during his service with the Chemical Warfare Service that he rediscovered Lewisite and assisted in its weaponization and mass production. [ 6 ] After the war, Lewis gave several high profile speeches in the defense of the Chemical Warfare Service and the use of chemical weapons in warfare. [ 7 ] This biographical article about an American chemist is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winford_Lee_Lewis
Winfrenatia is a genus that contains the oldest-known terrestrial lichen , [ 1 ] occurring in fossils preserved in the lower Devonian Rhynie chert . The genus contains the single species Winfrenatia reticulata , named for the texture of its surface. Both the species and the genus were described in 1997. [ 2 ] It comprises a thallus , made of layered, aseptate hyphae, with a number of depressions on its top surface. Each depression contains a net of hyphae holding a sheathed cyanobacterium . The fungus appears to be related to the Zygomycetes , and the photosynthetic partner of photobiont resembles the coccoid cyanobacteria Gloeocapsa and Chroococcidiopsis . [ 1 ] [ 2 ] [ 3 ] There may be two separate algae, making the lichen a symbiosis of three organisms. [ 3 ] This article related to the Devonian period is a stub . You can help Wikipedia by expanding it . This article about lichens or lichenology is a stub . You can help Wikipedia by expanding it . This paleobotany -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winfrenatia
Winfrenatia is a genus that contains the oldest-known terrestrial lichen , [ 1 ] occurring in fossils preserved in the lower Devonian Rhynie chert . The genus contains the single species Winfrenatia reticulata , named for the texture of its surface. Both the species and the genus were described in 1997. [ 2 ] It comprises a thallus , made of layered, aseptate hyphae, with a number of depressions on its top surface. Each depression contains a net of hyphae holding a sheathed cyanobacterium . The fungus appears to be related to the Zygomycetes , and the photosynthetic partner of photobiont resembles the coccoid cyanobacteria Gloeocapsa and Chroococcidiopsis . [ 1 ] [ 2 ] [ 3 ] There may be two separate algae, making the lichen a symbiosis of three organisms. [ 3 ] This article related to the Devonian period is a stub . You can help Wikipedia by expanding it . This article about lichens or lichenology is a stub . You can help Wikipedia by expanding it . This paleobotany -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winfrenatia_reticulata
Winfried Scharlau (12 August 1940, in Berlin – 26 November 2020) was a German mathematician. Scharlau received his doctorate in 1967 from the University of Bonn . His doctoral thesis Quadratische Formen und Galois-Cohomologie (Quadratic Forms and Galois Cohomology) was supervised by Friedrich Hirzebruch . [ 1 ] [ 2 ] Scharlau was at the Institute for Advanced Study for the academic year 1969–1970 and in spring 1972. [ 3 ] From 1970 he was a professor (most recent Institutsdirektor ) at the University of Münster , from where he retired. Scharlau's research deals with number theory and, in particular, the theory of quadratic forms, about which he wrote a 1985 monograph Quadratic and Hermitian Forms in Springer's series Grundlehren der mathematischen Wissenschaften . [ 4 ] [ 5 ] Scharlau was also an amateur ornithologist and author of two novels, I megali istoria - die große Geschichte (2nd edition 2001), set on the Greek island of Naxos , and Scharife (2001), set on the island of Zanzibar in the 19th century. [ 6 ] He also deals with the history of mathematics and wrote, with Hans Opolka, [ 7 ] a historically-oriented introduction to number theory. Their book presents, among other topics, the analytical class number formula of Dirichlet and the geometry of the numbers in the 19th century. [ 8 ] Scharlau wrote a multi-part biography of Alexander Grothendieck . [ 6 ] Scharlau was a corresponding member of the Göttingen Academy of Sciences and Humanities . From 1991 to 1992 he was president of the German Mathematical Society . In 1974 he was invited as speaker with talks On subspaces of inner product spaces at the International Congress of Mathematicians in Vancouver . [ 9 ] He was the father of the cognitive psychologist Ingrid Scharlau. [ 10 ]	https://en.wikipedia.org/wiki/Winfried_Scharlau
A wing is a type of fin that produces both lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform . Wing efficiency is expressed as lift-to-drag ratio , which compares the benefit of lift with the air resistance of a given wing shape, as it flies. Aerodynamics is the study of wing performance in air. Equivalent foils that move through water are found on hydrofoil power vessels and foiling sailboats that lift out of the water at speed and on submarines that use diving planes to point the boat upwards or downwards, while running submerged. Hydrodynamics is the study of foil performance in water. The word "wing" from the Old Norse vængr [ 1 ] for many centuries referred mainly to the foremost limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning has extended to include lift producing appendages of insects , bats , pterosaurs , boomerangs , some sail boats and aircraft , or the airfoil on a race car . [ 2 ] The design and analysis of the wings of aircraft is one of the principal applications of the science of aerodynamics , which is a branch of fluid mechanics . The properties of the airflow around any moving object can be found by solving the Navier-Stokes equations of fluid dynamics . Except for simple geometries, these equations are difficult to solve. [ 3 ] Simpler explanations can be given. For a wing to produce "lift", it must be oriented at a suitable angle of attack relative to the flow of air past the wing. When this occurs, the wing deflects the airflow downwards, "turning" the air as it passes the wing. Since the wing exerts a force on the air to change its direction, the air must exert a force on the wing, equal in size but opposite in direction. This force arises from different air pressures that exist on the upper and lower surfaces of the wing. [ 4 ] [ 5 ] [ 6 ] Lower-than-ambient air pressure is generated on the top surface of the wing, with a higher-than ambient-pressure on the bottom of the wing. (See: airfoil ) These air pressure differences can be either measured using a pressure-measuring device, or can be calculated from the airspeed using physical principles –including Bernoulli's principle , which relates changes in air speed to changes in air pressure. The lower air pressure on the top of the wing generates a smaller downward force on the top of the wing than the upward force generated by the higher air pressure on the bottom of the wing. This gives an upward force on the wing. This force is called the lift generated by the wing. The different velocities of the air passing by the wing, the air pressure differences, the change in direction of the airflow, and the lift on the wing are different ways of describing how lift is produced so it is possible to calculate lift from any one of the other three. For example, the lift can be calculated from the pressure differences, or from different velocities of the air above and below the wing, or from the total momentum change of the deflected air. Fluid dynamics offers other approaches to solving these problems –all which methods produce the same answer if correctly calculated. Given a particular wing and its velocity through the air, debates over which mathematical approach is the most convenient [ citation needed ] to use can be mistaken by those not familiar with the study of aerodynamics as differences of opinion about the basic principles of flight. [ 7 ] Wings with an asymmetrical cross-section are the norm in subsonic flight . Wings with a symmetrical cross-section can also generate lift by using a positive angle of attack to deflect air downward. Symmetrical airfoils have higher stalling speeds than cambered airfoils of the same wing area [ 8 ] but are used in aerobatic aircraft as they provide the same flight characteristics whether the aircraft is upright or inverted. [ 9 ] Another example comes from sailboats, where the sail is a thin sheet. [ 10 ] For flight speeds near the speed of sound ( transonic flight ), specific asymmetrical airfoil sections are used to minimize the very pronounced increase in drag associated with airflow near the speed of sound. [ 11 ] These airfoils, called supercritical airfoils , are flat on top and curved on the bottom. [ 12 ] Aircraft wings may feature some of the following: Aircraft wings may have various devices, such as flaps or slats, that the pilot uses to modify the shape and surface area of the wing to change its operating characteristics in flight. Besides fixed-wing aircraft , applications for wing shapes include: [ citation needed ] In 1948, Francis Rogallo invented the fully limp flexible wing. Domina Jalbert invented flexible un-sparred ram-air airfoiled thick wings. Wings have evolved multiple times in history: in insects , dinosaurs (see bird wing ), mammals (see bats ), fish, reptiles (see pterosaurs ), and plants. Wings of birds, bats, and pterosaurs all evolved from existing limbs, however insect wings evolved as a completely separate structure. [ 13 ] Wings facilitated increased locomotion , dispersal, and diversification. [ 14 ] Various species of penguins and other flighted or flightless water birds such as auks , cormorants , guillemots , shearwaters , eider and scoter ducks and diving petrels are efficient underwater swimmers, and use their wings to propel through water. [ 15 ] Natural world: Aviation: Sailing:	https://en.wikipedia.org/wiki/Wing
Wing-assisted incline running (abbreviated as "WAIR") is a running behavior observed in living birds as well as a model proposed to explain the evolution of avian flight . WAIR allows birds to run up steep or vertical inclines by flapping their wings, scaling greater inclines than possible through running alone. The WAIR origin-of-flight hypothesis proposes that the nascent wings of theropod dinosaurs were used to propel the animal up slopes, such as cliffs or trees, in a similar manner to that employed by modern birds, and that powered flight eventually evolved from this usage. [ 1 ] During its proposal, it was suggested that WAIR might have plausibly been used by feathered theropods like Caudipteryx to develop aerial flight. [ 2 ] Wing-assisted incline running has been studied extensively in chicks of the chukar partridge ( Alectoris chukar ), [ 2 ] [ 3 ] [ 4 ] and has been observed in juveniles and adults of other species of Galliformes as well as the rock dove ( Columba livia ). [ 5 ] In chukar chicks, WAIR was experimentally demonstrated by comparing maximum inclines ascended by normal chicks to those with wing feathers trimmed or plucked entirely. On both smooth and rough surfaces, normal chicks were able to run up much steeper slopes than the other two groups, reaching maximum angles of 105° from the horizontal. Chicks used running alone at slopes up to 45°, then employed wing-flapping at greater slopes, and maximum slope successfully scaled increased with age. [ 2 ] When baby chukars hatch, they have not yet developed their flight feathers. As the babies develop, it takes approximately one week for feathers to appear, and about three weeks for the ability to fly. As the baby chukars grow and before flying for the first time, they use WAIR as a transition to adult flight. [ 4 ] WAIR has also been studied in the Australian brushturkey ( Alectura lathami ), although maximum slope decreased with age, such that hatchlings could scale greater slopes (up to 110°) than adults (up to 70°). [ 6 ] In rock doves, adults employ WAIR at angles greater than 65°. [ 5 ] These galliformes might use WAIR instead of normal flight to reach tree branches because WAIR uses less energy than normal flight. Fewer muscles are used in the process of WAIR than normal flight, specifically pectoral and shoulder muscles which contribute to wing flapping. [ 5 ] This provides an additional explanation as to why birds continue to use WAIR: it is faster than normal flight take-off, and running requires less energy than does flying. Therefore; the hindlimbs, in conjunction with the wings, may produce quick bouts of energy which may allow the bird to catch prey. [ 7 ] This strategy also allows energy to be stored for use in a fight-or-flight situation such as to escape becoming eaten or caught. [ 5 ] [ 6 ] WAIR imposes less aerodynamic and physical forces than normal avian flight on the bird, an advantageous trait which may increase fitness. [ 6 ] WAIR could have been used for balance purposes. [ 3 ] Many theories propose that the manifestation of WAIR in birds is for predatory escape purposes, in that they are able to run up extremely steep and past vertical slopes (such as the trunk of a tree) to escape from a ground-dwelling predator. [ 3 ] [ 5 ] Another reason for the manifestation of WAIR may be for dispersal or to find food or resources, but this idea is mostly proposed as a survival strategy. [ 7 ] Whether it is to evade predation, catch prey, enhance reproductive success, or simply a variation imposed for dispersal, flight among avian creatures has evolved to be a highly successful trait. The WAIR hypothesis for the origin of flight is a version of the " cursorial model " of the evolution of avian flight, in which birds' wings originated from forelimb modifications that provided downforce, enabling the proto-birds to run up extremely steep slopes such as the trunks of trees. The hypothesis was prompted by the observation of living young chukar chicks using WAIR, and proposes that dinosaur wings developed their aerodynamic functions as a result of the need to run quickly up very steep slopes such as tree trunks, possibly to escape from predators. [ 2 ] Originally, it was thought that birds need downforce to give their feet increased grip in this scenario. [ 2 ] [ 3 ] However, a study found lift generated from wings to be the primary factor for successfully accelerating, indicating the onset of flight ability was constrained by neuromuscular control or power rather than by the shape of the wing itself, and that partially developed wings not yet capable of flight could indeed provide useful lift during WAIR. [ 4 ] Additionally, when both the power and work needed for WAIR were examined, it was identified that the need for pectoral muscles in flight increases with the angle being scaled. Thus, WAIR is a hypothesis providing a model for an evolutionary transition from terrestrial to aerial locomotion as birds skeletally adapted to meet the requirements to scale steeper and steeper inclines by flight. [ 5 ] This might have allowed smaller, potentially juvenile maniraptorans to scale the sides of trees to escape predators that were too big to climb. WAIR may have been present in oviraptorosaurs and therizinosauroids , but as the adults, especially of therizinosauroids, would probably break the trees trying to climb, their hatchlings or chicks would have made it up easily. Because of this way to escape predation, early maniraptorans might have evolved their long arms, true feathers and fused wishbones . [ 8 ] One possible problem with the WAIR origin of flight hypothesis was noticed by Philip Senter. He argued that early birds, including Archaeopteryx , lacked the shoulder mechanism by which modern birds' wings produce swift, powerful upstrokes. Since the downforce on which WAIR depends is generated by upstrokes, Senter argued that early birds were incapable of WAIR or flapping flight. [ 9 ] Evidence has been proposed against the WAIR hypothesis, stating that it is too simplistic and does not take additional information into effect. There have been additional mechanisms suggested, such as climbing claws, that would have provided an advantage for the birds, but are absent in fossil records or extant birds. [ 10 ] Other arguments against WAIR include a lack of fossil evidence and no additional intermediate or transition stages available for study which would provide supplementary evidence for WAIR. [ 3 ] [ 7 ]	https://en.wikipedia.org/wiki/Wing-assisted_incline_running
Wingcon is a German company that produces telecommunications products for the railway industry and other mobile mission-critical communications. The company specializes in design, developing and providing telecom products as well as consulting services worldwide with focus on GSM-Railway . [ 1 ] Wingcon's communication products include Blackbox Recording Centers (voice & video recording systems), Short Message Service Centers , SMS gateways, location-based services , as well as billing mediation devices. [ 2 ] [ 3 ]	https://en.wikipedia.org/wiki/Wingcon
The wingspan (or just span ) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of 60.93 metres (199 ft 11 in), [ 1 ] and a wandering albatross ( Diomedea exulans ) caught in 1965 had a wingspan of 3.63 metres (11 ft 11 in), the official record for a living bird. The term wingspan, more technically extent , is also used for other winged animals such as pterosaurs , bats , insects , etc., and other aircraft such as ornithopters . In humans , the term wingspan also refers to the arm span , which is the distance between the length from the end of an individual's arm (measured at the fingertips) to the individual's fingertips on the other arm when raised parallel to the ground at shoulder height. The wingspan of an aircraft is always measured in a straight line, from wingtip to wingtip, regardless of wing shape or sweep . The lift from wings is proportional to their area, so the heavier the animal or aircraft the bigger that area must be. The area is the product of the span times the width ( mean chord ) of the wing, so either a long, narrow wing or a shorter, broader wing will support the same mass. For efficient steady flight, the ratio of span to chord, the aspect ratio , should be as high as possible (the constraints are usually structural) because this lowers the lift-induced drag associated with the inevitable wingtip vortices . Long-ranging birds, like albatrosses, and most commercial aircraft maximize aspect ratio. Alternatively, animals and aircraft which depend on maneuverability (fighters, predators and prey, as well as those who live amongst trees and bushes, insect catchers, etc.) need to be able to roll fast to turn, and the high moment of inertia of long narrow wings, as well as the high angular drag and quick balancing of aileron lift with wing lift at a low rotation rate, produce lower roll rates . For them, short-span, broad wings are preferred. Additionally, ground handling in aircraft is a significant problem for very high aspect ratios and flying animals may encounter similar issues. The highest aspect ratio of man-made wings are aircraft propellers, in their most extreme form as helicopter rotors . To measure the wingspan of a bird, a live or freshly-dead specimen is placed flat on its back, the wings are grasped at the wrist joints and the distance is measured between the tips of the longest primary feathers on each wing. [ 2 ] The wingspan of an insect refers to the wingspan of pinned specimens, and may refer to the distance between the centre of the thorax and the apex of the wing doubled or to the width between the apices with the wings set with the trailing wing edge perpendicular to the body. In basketball and gridiron football , a fingertip-to-fingertip measurement is used to determine the player's wingspan, also called armspan. This is called reach in boxing terminology. The wingspan of 16-year-old BeeJay Anya , a top basketball Junior Class of 2013 prospect who played for the NC State Wolfpack , was officially measured at 7 feet 9 inches (2.36 m) across, one of the longest of all National Basketball Association draft prospects, and the longest ever for a non-7-foot player, though Anya went undrafted in 2017. [ 3 ] The wingspan of Manute Bol , at 8 feet 6 inches (2.59 m), is (as of 2013) the longest in NBA history, and his vertical reach was 10 feet 5 inches (3.18 m). [ 4 ] [ 5 ]	https://en.wikipedia.org/wiki/Wingspan
The Winkler test is used to determine the concentration of dissolved oxygen in water samples. Dissolved oxygen (D.O.) is widely used in water quality studies and routine operation of water reclamation facilities to analyze its level of oxygen saturation . In the test, an excess of manganese(II) salt, iodide (I − ) and hydroxide (OH − ) ions are added to a water sample causing a white precipitate of Mn(OH) 2 to form. This precipitate is then oxidized by the oxygen that is present in the water sample into a brown manganese -containing precipitate with manganese in a more highly oxidized state (either Mn(III) or Mn(IV)). In the next step, a strong acid (either hydrochloric acid or sulfuric acid ) is added to acidify the solution. The brown precipitate then converts the iodide ion (I − ) to iodine . The amount of dissolved oxygen is directly proportional to the titration of iodine with a thiosulfate solution. [ 1 ] Today, the method is effectively used as its colorimetric modification, where the trivalent manganese produced on acidifying the brown suspension is directly reacted with ethylenediaminetetraacetic acid to give a pink color. [ 2 ] As manganese is the only common metal giving a color reaction with ethylenediaminetetraacetic acid, it has the added effect of masking other metals as colorless complexes. The test was originally developed by Ludwig Wilhelm Winkler, in later literature referred to as Lajos Winkler , while working at Budapest University on his doctoral dissertation in 1888. [ 3 ] The amount of dissolved oxygen is a measure of the biological activity of the water masses. Phytoplankton and macroalgae present in the water mass-produce oxygen by way of photosynthesis . Bacteria and eukaryotic organisms (zooplankton, fish) consume this oxygen through cellular respiration . The result of these two mechanisms determines the concentration of dissolved oxygen, which in turn indicates the production of biomass. The difference between the physical concentration of oxygen in the water (or the theoretical concentration if there were no living organisms) and the actual concentration of oxygen is called the biochemical demand in oxygen. The Winkler test is often controversial as it is not 100% accurate and the oxygen levels may fluctuate from test to test despite using the same constant sample. In the first step, manganese(II) sulphate (at 48% of the total volume) is added to an environmental water sample. Next, potassium iodide (15% in potassium hydroxide 70%) is added to create a pinkish-brown precipitate. In the alkaline solution, dissolved oxygen will oxidize manganese(II) ions to the tetravalent state. Mn has been oxidised to 4+, and MnO(OH) 2 appears as a brown precipitate. There is some uncertainty about whether the oxidised manganese is tetravalent or trivalent . Some sources claim that Mn(OH) 3 is the brown precipitate, but hydrated MnO 2 may also give the brown colour. The second part of the Winkler test reduces (acidifies) the solution. The precipitate will dissolve back into solution as the H + reacts with the O 2− and OH − to form water. The acid facilitates the conversion by the brown, Manganese-containing precipitate of the Iodide ion into elemental Iodine. The Mn(SO 4 ) 2 formed by the acid converts the iodide ions into iodine, itself being reduced back to manganese(II) ions in an acidic medium. Thiosulfate is used, with a starch indicator, to titrate the iodine. From the above stoichiometric equations, we can find that: Therefore, after determining the number of moles of iodine produced, we can work out the number of moles of oxygen molecules present in the original water sample. The oxygen content is usually presented in milligrams per liter (mg/L). The success of this method is critically dependent upon the manner in which the sample is manipulated. At all stages, steps must be taken to ensure that oxygen is neither introduced to nor lost from the sample. Furthermore, the water sample must be free of any solutes that will oxidize or reduce iodine. Instrumental methods for measurement of dissolved oxygen have widely supplanted the routine use of the Winkler test, although the test is still used to check instrument calibration. To determine five-day biochemical oxygen demand (BOD 5 ), several dilutions of a sample are analyzed for dissolved oxygen before and after a five-day incubation period at 20 °C in the dark. In some cases, bacteria are used to provide a standardized community to uptake oxygen while consuming the organic matter in the sample; these bacteria are known as "seed". The difference in DO and the dilution factor are used to calculated BOD 5 . The resulting number (usually reported in parts per million or milligrams per liter) is useful in determining the relative organic strength of sewage or other polluted waters. The BOD 5 test is an example of analysis that determines classes of materials in a sample. A Winkler bottle is a piece of laboratory glassware specifically made for carrying out the Winkler test. These bottles have conical tops and a close fitting stopper to aid in the exclusion of air bubbles when the top is sealed. This is important because oxygen in trapped air would be included in the measurement and would affect the accuracy of the test. [ 4 ]	https://en.wikipedia.org/wiki/Winkler_titration
Winmostar is a molecular modelling and visualisation software program that computes quantum chemistry, molecular dynamics , and solid physics. [ 1 ] [ 2 ] This article about molecular modelling software is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winmostar
Winnie Kwai-Wah Wong-Ng ( Chinese : 黃桂華 ) [ 1 ] is a Chinese-American physical chemist. She is a research chemist at the ceramics division at the National Institute of Standards and Technology . Her research includes energy applications, crystallography, thermoelectric standards, metrology, and data, sorbent materials for sustainability, and high throughput combinatorial approach for novel materials discovery and property optimization for energy conversion applications. She is a fellow of the International Centre for Diffraction Data , American Ceramic Society , American Crystallographic Association , and the American Association for the Advancement of Science . Wong-Ng was twice awarded the Department of Commerce Bronze Medal . Wong-Ng completed a B.Sc. in chemistry and physics at Chinese University of Hong Kong in 1969. She earned a Ph.D. in inorganic and physical chemistry at Louisiana State University in 1974. [ 2 ] Wong-Ng was a research associate and lecturer in the chemistry department at University of Toronto . From 1981 to 1985, she was a critical review scientist at the International Centre for Diffraction Data . Wong-Ng was a research scientist in the chemistry department at University of Maryland, College Park and a research associate in the ceramics division at the National Bureau of Standards from 1985 to 1988. Since 1988, Wong-Ng works as a research chemist in the ceramics division at the National Institute of Standards and Technology . [ 2 ] She served as president the Association of NIST Asian Pacific Americans from 2000 to 2003. [ 2 ] Wong-Ng's research interest includes materials for energy applications, thermoelectric standards, metrology, and data, sorbent materials for sustainability, and high throughput combinatorial approach for novel materials discovery and property optimization for energy conversion applications. She also researches crystallography, phase equilibria, and crystal chemistry of energy materials to understand their structure and property relationships. Structural studies involve synchrotron X-ray and neutron diffraction techniques. [ 2 ] In 2000, Wong-Ng became a fellow of the International Centre for Diffraction Data (ICDD). She was awarded fellow of the American Ceramic Society in 2002. In 2002 and 2008, she won the Department of Commerce Bronze Medal . In 2014, Wong-Ng was made fellow of the American Crystallographic Association . In 2012, she became a distinguished fellow of the ICDD and a Fellow of the American Association for the Advancement of Science . She became an academician of the World Academy of Ceramics in 2018. [ 2 ] This article incorporates public domain material from the National Institute of Standards and Technology	https://en.wikipedia.org/wiki/Winnie_Wong-Ng
Winnowing is a process by which chaff is separated from grain . It can also be used to remove pests from stored grain. Winnowing usually follows threshing in grain preparation. In its simplest form, it involves throwing the mixture into the air so that the wind blows away the lighter chaff, while the heavier grains fall back down for recovery. Techniques included using a winnowing fan (a shaped basket shaken to raise the chaff) or using a tool (a winnowing fork or shovel) on a pile of harvested grain. The winnowing-fan (λίκνον [ líknon ], also meaning a "cradle") featured in the rites accorded Dionysus and in the Eleusinian Mysteries : "it was a simple agricultural implement taken over and mysticized by the religion of Dionysus," Jane Ellen Harrison remarked. [ 1 ] Dionysus Liknites ("Dionysus of the winnowing fan") was wakened by the Dionysian women, in this instance called Thyiades , in a cave on Parnassus high above Delphi ; the winnowing-fan links the god connected with the mystery religions to the agricultural cycle, but mortal Greek babies too were laid in a winnowing-fan. [ 2 ] In Callimachus 's Hymn to Zeus , Adrasteia lays the infant Zeus in a golden líknon , her goat suckles him and he is given honey. In the Odyssey , the dead oracle Teiresias tells Odysseus to walk away from Ithaca with an oar until a wayfarer tells him it is a winnowing fan (i.e., until Odysseus has come so far from the sea that people don't recognize oars), and there to build a shrine to Poseidon. In ancient China, the method was improved by mechanization with the development of the rotary winnowing fan, which used a cranked fan to produce the airstream. [ 3 ] This was featured in Wang Zhen 's book the Nong Shu of 1313 AD. In Saxon settlements such as one identified in Northumberland as Bede 's Ad Gefrin [ 4 ] (now called Yeavering ) the buildings were shown by an excavator's reconstruction to have opposed entries. In barns a draught created by the use of these opposed doorways was used in winnowing. [ 5 ] The technique developed by the Chinese was not adopted in Europe until the 18th century when winnowing machines used a 'sail fan'. [ 6 ] The rotary winnowing fan was exported to Europe, brought there by Dutch sailors between 1700 and 1720. Apparently, they had obtained them from the Dutch settlement of Batavia in Java, Dutch East Indies. The Swedes imported some from south China at about the same time and Jesuits had taken several to France from China by 1720. Until the beginning of the 18th century, no rotary winnowing fans existed in the West. [ 7 ] The development of the winnowing barn allowed rice plantations in South Carolina to increase their yields dramatically. In 1737 Andrew Rodger, a farmer on the estate of Cavers in Roxburghshire , developed a winnowing machine for corn, called a 'Fanner'. These were successful and the family sold them throughout Scotland for many years. Some Scottish Presbyterian ministers saw the fanners as sins against God, for the wind was a thing specially made by him and an artificial wind was a daring and impious attempt to usurp what belonged to God alone. [ 8 ] As the Industrial Revolution progressed, the winnowing process was mechanized by the invention of additional winnowing machines, such as fanning mills. The dictionary definition of winnowing at Wiktionary	https://en.wikipedia.org/wiki/Winnowing
In sedimentology , winnowing is the natural removal of fine material from a coarser sediment by wind or flowing water. Once a sediment has been deposited, subsequent changes in the speed or direction of wind or water flowing over it can agitate the grains in the sediment and allow the preferential removal of the finer grains. This action can improve the sorting and increase the mean grain size of a sediment after it has been deposited. [ 1 ] The term winnowing is from the analogous process for the agricultural separation of wheat from chaff . The dictionary definition of winnowing at Wiktionary This sedimentology article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winnowing_(sedimentology)
The Winnowing Basket mansion (箕宿, pinyin : Jī Xiù) is one of the Twenty-Eight Mansions of the Chinese constellations . It is one of the eastern mansions of the Azure Dragon . [ 1 ] [ 2 ] [ 3 ] This constellation -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winnowing_Basket_(constellation)
The Winogradsky column is a simple device for culturing a large diversity of microorganisms . Invented in the 1880s by Sergei Winogradsky , the device is a column of pond mud and water mixed with a carbon source such as newspaper (containing cellulose ), blackened marshmallows or egg-shells (containing calcium carbonate ), and a sulfur source such as gypsum ( calcium sulfate ) or egg yolk. Incubating the column in sunlight for months results in an aerobic / anaerobic gradient as well as a sulfide gradient. These two gradients promote the growth of different microorganisms such as Clostridium , Desulfovibrio , Chlorobium , Chromatium , Rhodomicrobium , and Beggiatoa , as well as many other species of bacteria, cyanobacteria, and algae. The column provides numerous gradients, depending on additive nutrients, from which the variety of aforementioned organisms can grow. The aerobic water phase and anaerobic mud or soil phase are one such distinction. Because of oxygen's low solubility in water, the water quickly becomes anoxic towards the interface of the mud and water. Anaerobic phototrophs are still present to a large extent in the mud phase, and there is still capacity for biofilm creation and colony expansion. Algae and other aerobic phototrophs are present along the surface and water of the upper half of the columns. The column is a rough mixture of ingredients – exact measurements are not critical. A tall glass (30 cm long, >5 cm wide) is filled one third full of pond mud, omitting any sticks, debris, and air bubbles. Supplementation of ~0.25% w/w calcium carbonate and ~0.50% w/w calcium sulfate or sodium sulfate is required (ground eggshell and egg yolk respectively are rich in these minerals), mixed in with some shredded newspaper, filter paper or hay (for cellulose). An additional anaerobic layer, this time of unsupplemented mud, brings the container to two thirds full. Alternatively, some procedures call for sand to be used for the layer above the enriched sediment as to allow for easier observation and sampling of resulting populations. This is followed by water from the pond to saturate the mud (or sand) and occupy half the remaining volume. The column is sealed tightly to prevent evaporation of water and incubated for several months in strong natural light. After the column is sealed tightly the anaerobic bacteria will develop first, including Clostridium spp. These anaerobic bacteria will consume the cellulose as an energy source. Once this commences they create CO 2 that is used by other bacteria and thus the cycle begins. Eventually colour layers of different bacteria will appear in the column. At the bottom of the column will be black anaerobic H 2 S dominated zone with sulfur reducing bacteria, the layer above will be green sulfur photosynthetic anaerobic bacteria, then the layer will be purple which is sulfur anaerobic bacteria, followed by another column of purple anaerobic non-sulfur bacteria and at the top will be a layer of Cyanobacteria which are sulfur oxidising bacteria. This top layer of aerobic bacteria produces O 2 which feeds back into the column to facilitate further reactions. [ 1 ] While the Winogradsky column is an excellent tool to see whole communities of bacteria, it does not allow one to see the densities or individual bacterial colonies. It also takes a long time to complete its cycle. However its importance in environmental microbiology should not be overlooked and it is still an excellent tool to determine the major bacterial communities in a sample. [ 2 ]	https://en.wikipedia.org/wiki/Winogradsky_column
Winston Wen-Yang Wong OBE ( Chinese : 王文洋 ; pinyin : Wáng Wényáng ; born 2 April 1951 in Taipei County (now New Taipei City), Taiwan ) is the eldest son of Wang Yung-ching , chair of the Formosa Plastics Group (FPG), by his second wife. [ 1 ] [ 2 ] Wong is now a widower with a son and a daughter after his wife died of stomach cancer in 2007. [ 3 ] Wong holds degrees in physics , applied optics , and chemical engineering from Imperial College London . [ 4 ] His English name was chosen during his study in the United Kingdom . Wong was executive vice president of Nan Ya Plastics , an FPG subsidiary, until a widely publicized affair (and the resulting 14% drop in FPG stocks) led to his dismissal in December 1995. His father then “banished” Wong to the United States, where he spent one year teaching at the business school of the University of California, Berkeley . While in the United States, Wong met Jiang Mianheng , son of Jiang Zemin , the General Secretary of the Chinese Communist Party at that time. [ 5 ] In 2000, Wong and Jiang Mianheng co-founded the US$1.63 billion Grace Semiconductor Manufacturing Corp. joint venture in Shanghai , China . Though Wong serves as president and CEO of that company, Wong himself is not a stockholder, due to cross-strait investment restrictions imposed by the Republic of China (ROC). [ 1 ] Wong also serves as chair of the Hung Jen Group (宏仁集團) and chair of the Grace THW Group (宏仁企业集团), [ 6 ] which are heavily invested in mainland China’s petrochemical and electronics industries, respectively. [ 7 ] The Winston Wong Centre for Bio-Inspired Technology was created at Imperial College London in 2009. [ 8 ] In 2015, Wong was named to “Top 100 Chinese for Economic Achievements and Contributions” list by Management World Magazine . [ 9 ] As an entrepreneur, Wong has long been a vocal supporter for increased levels of trade cooperation between Taiwan and the West, and free trade agreements in general. On 26 February 2012, Forbes featured an OP/ED written by Wong in which he discussed, “A Free Trade Agenda For the U.S. and Taiwan”. The premise of the article being that despite global exports totaling $274 billion in 2010, Taiwan has had difficulty establishing a footprint in substantial global trade agreements. Because of Taiwan’s complex diplomatic relations, it has had trouble entering substantial trade pacts with the economic powerhouses of the United States and North American Free Trade Agreement. [ 10 ] In June 2010, Wong agreed to be the main sponsor of the Moon-Regan Trans-Antarctic expedition led by Andrew Regan and Andrew Moon. [ 11 ] The Expedition will travel 3,600 miles across Antarctica, from Patriot Hills on the west coast to the South Pole, heading north from there through the Trans-Antarctic Mountain Range, down the Leverett Glacier and across the Ross Ice Shelf to the coast at McMurdo. [ 12 ] The expedition has partnered with Imperial College London [ 13 ] to carry out a wide range of scientific objectives. The team is travelling in three vehicles across Antarctica, including two mobile laboratories and the Winston Wong Bio-Inspired Ice Vehicle (WWBIV). The WWBIV will be the first bio-fuelled vehicle on Antarctica to endeavor to reach the Geographic South Pole . [ 14 ]	https://en.wikipedia.org/wiki/Winston_Wong
Wintel ( portmanteau of Windows and Intel ) is the partnership of Microsoft and Intel producing personal computers (PCs) using Intel x86 -compatible processors running Windows . By the early 1980s, the chaos and incompatibility that was rife in the early microcomputer market had given way to a smaller number of de facto industry standards, including the S-100 bus expansion board, the CP/M operating system, the Apple II home computer, the use of the programming language Microsoft BASIC in read-only memory (ROM), and the 5 + 1 ⁄ 4 inch floppy drive storage medium. Firms competed fiercely to control the industry, and innovation in hardware and software was the rule. Microsoft Windows and Intel processors gained ascendance and their ongoing alliance gave them market dominance. [ 1 ] Intel has claimed that this partnership has enabled the two companies to give customers the benefit of "a seemingly unending spiral of falling prices and rising performance". [ 2 ] In addition, they claim a "history of innovation" and "a shared vision of flexible computing for the agile business". In 1981, IBM entered the microcomputer market. The IBM PC was created by a small subdivision of the firm. It was unusual for an IBM product because it was largely sourced from outside component suppliers and was intended to run third-party operating systems and software. IBM published the technical specifications and schematics of the PC, which allowed third-party companies to produce compatible hardware, the so-called open architecture . The IBM PC became one of the most successful computers of all time. The key feature of the IBM PC was that it had IBM's enormous public respect behind it. It was an accident of history [ editorializing ] that the IBM PC happened to have an Intel CPU (instead of the technically superior [ 3 ] Motorola 68000 that had been tipped for it, or an IBM in-house design), and that it shipped with IBM PC DOS (a licensed version of Microsoft's MS-DOS ) rather than the CP/M-86 operating system, but these accidents were to have enormous significance in later years. Because the IBM PC was an IBM product with the IBM badge, personal computers became respectable. It became easier for a business to justify buying a microcomputer than it had been even a year or two before, and easiest of all to justify buying the IBM Personal Computer . [ citation needed ] Since the PC architecture was well documented in IBM's manuals, and PC DOS was designed to be similar to the earlier CP/M operating system, the PC soon had thousands of different third-party add-in cards and software packages available. This made the PC the preferred option for many, since the PC supported the hardware and software they needed. Industry competitors took one of several approaches to the changing market. Some (such as Apple , Amiga , Atari , and Acorn ) persevered with their independent and quite different systems. Of those systems, Apple's Mac is the only one remaining on the market. Others (such as Digital , then the world's second-largest computer company, Hewlett-Packard, and Apricot ) concentrated on making similar but technically superior models. Other early market leaders (such as Tandy-Radio Shack or Texas Instruments) stayed with outdated architectures and proprietary operating systems for some time before belatedly realizing which way market trends were going and switching to the most successful long-term business strategy, which was to build a machine that duplicated the IBM PC as closely as possible and sell it for a slightly lower price, or with higher performance. Given the very conservative engineering of the early IBM personal computers and their higher than average prices, this was not a terribly difficult task at first, bar only the great technical challenge of crafting a BIOS that duplicated the function of the IBM BIOS exactly but did not infringe on copyrights. The two early leaders in this last strategy were both start-up companies: Columbia Data Products and Compaq . They were the first to achieve reputations for very close compatibility with the IBM machines, which meant that they could run software written for the IBM machine without recompilation. Before long, IBM had the best-selling personal computer in the world and at least two of the next-best sellers were, for practical purposes, identical. For the software industry, the effect was profound. First, it meant that it was rational to write for the IBM PC and its clones as a high priority, and port versions for less common systems at leisure. Second (and even more importantly), when a software writer in pre-IBM days had to be careful to use as plain a subset of the possible techniques as practicable (so as to be able to run on any hardware that ran CP/M), with a major part of the market now all using the same exact hardware (or a very similar clone of it) it was practical to take advantage of any and every hardware-specific feature offered by the IBM. Independent BIOS companies like Award , Chips and Technologies , and Phoenix began to market a clean room BIOS that was 100% compatible with IBM's, and from that time on any competent computer manufacturer could achieve IBM compatibility as a matter of routine. From around 1984, the market was fast growing but relatively stable. There was as yet no sign of the "Win" half of "Wintel," though Microsoft was achieving enormous revenues from DOS sales both to IBM and to an ever-growing list of other manufacturers who had agreed to buy an MS-DOS license for every machine they made, even those that shipped with competing products. As for Intel, every PC made either had an Intel processor or one made by a second source supplier under license from Intel. Intel and Microsoft had enormous revenues, Compaq and many other makers between them made far more machines than IBM, but the power to decide the shape of the personal computer rested firmly in IBM's hands. In 1987, IBM introduced the PS/2 computer line. Although the open architecture of the PC and its successors had been a great success for them, and they were the biggest single manufacturer, most of the market was buying faster and cheaper IBM-compatible machines made by other firms. The PS/2s remained software compatible, but the hardware was quite different. It introduced the technically superior Micro Channel architecture bus for higher speed communication within the system, but failed to maintain the open AT bus (later called the ISA bus ), which meant that none of the millions of existing add-in cards would function. In other words, the new IBM machines were not IBM-compatible. Further, IBM planned the PS/2 in such a way that for both technical and legal reasons it would be very difficult to clone. Instead, IBM offered to sell a PS/2 licence to anyone who could afford the royalty. They would not only require a royalty for every PS/2-compatible machine sold, but also a payment for every IBM-compatible machine the particular maker had ever made in the past. Many PC manufacturers signed up as PS/2 licensees. (Apricot, who had lost badly by persevering with their "better PC than IBM" strategy up until this time, was one of them, but there were many others.) Many others decided to hold off before committing themselves. Some major manufacturers, known as the Gang of Nine , decided to group together and decide on a bus type that would be open to all manufacturers, as fast as or faster than IBM's Microchannel, and yet still retain backward compatibility with ISA. This was the crucial turning point: the industry as a whole was no longer content to let IBM make all the major decisions about technical direction. In the event, the new EISA bus was itself a commercial failure beyond the high end: By the time the cost of implementing EISA was reduced to the extent that it would be implemented in most desktop PCs, the much cheaper VESA Local Bus had removed most of the need for it in desktop PCs (though it remained common in servers due to for example the possibility of data corruption on hard disk drives attached to VLB controllers), and Intel's PCI bus was just around the corner. But although very few EISA systems were sold, it had achieved its purpose: IBM no longer controlled the computer industry. IBM would belatedly amend the PS/2 series with the PS/ValuePoint line, which tracked the features of the emerging ad hoc platform. At around this same time, the end of the 1980s and the beginning of the 1990s, Microsoft's Windows operating environment started to become popular, and Microsoft's competitor Digital Research started to recover a share of the DOS press and DOS market with DR-DOS . IBM planned to replace DOS with the vastly superior OS/2 (originally an IBM/Microsoft joint venture, and unlike the PS/2 hardware, highly backward compatible), but Microsoft preferred to push the industry in the direction of its own product, Windows. With IBM suffering its greatest ever public humiliation in the wake of the PS/2 disaster, massive financial losses, and a marked lack of company unity or direction, Microsoft's combination of a soft marketing voice and a big financial stick was effective: Windows became the de facto standard . For the competing computer manufacturers, large or small, the only common factors to provide joint technical leadership were operating software from Microsoft, and CPUs from Intel. Over the following years, both firms in the Wintel partnership would attempt to extend their dominance. Intel made a successful major push into the motherboard and chipset markets—becoming the largest motherboard manufacturer in the world and, at one stage, almost the only chipset manufacturer—but badly fumbled its attempt to move into the graphics chip market, and (from 1991) faced sharp competition in its core CPU territory from AMD , Cyrix , VIA and Transmeta . Microsoft fared better. In 1990, Microsoft had two competitors in its core market (Digital Research and IBM), Intel had none. By 1996, Intel had two competitors in its core market (CPUs), while Microsoft had none. Microsoft had pursued a policy of insisting on per-processor royalties, thus making competing operating systems unattractive to computer manufacturers and provoking regulatory scrutiny from the European Commission and US authorities, leading to an undertaking by Microsoft to cease such practices. [ 4 ] However, the integration of DOS into Windows 95 was the masterstroke: not only were the other operating system vendors frozen out, Microsoft could now require computer manufacturers to comply with its demands on pain of higher prices (as when it required IBM to stop actively marketing OS/2 or else pay more than twice as much for Windows 95 as its competitor Compaq) [ citation needed ] or by withholding "Designed for Windows 95" endorsement (which was regarded as an essential hardware marketing tool). Microsoft was also able to require that free publicity be given over to them by hardware makers. (For example, the Windows key advertising symbols on nearly all modern keyboards, or the strict license restrictions on what may or may not be displayed during system boot and on the Windows desktop.) Also, Microsoft was able to take over most of the networking market (formerly the domain of Artisoft 's LANtastic and Novell 's NetWare ) with Windows NT , and the business application market (formerly led by Lotus and WordPerfect ) with Microsoft Office . Although Microsoft is by far the dominant player in the Wintel partnership now, Intel's continuing influence should not be underestimated. Intel and Microsoft, once the closest of partners, have operated at an uneasy distance from one another since their first major dispute, which had to do with Intel's heavy investment in the 32-bit optimized Pentium Pro and Microsoft's delivery of an unexpectedly high proportion of 16-bit code in Windows 95. Both firms talk with one another's competitors from time to time, most notably with Microsoft's close relationship with AMD and the development of Windows XP Professional x64 Edition utilizing AMD-designed 64-bit extensions to the x86 architecture, and Intel's decision to sell its processors to Apple Inc. The Wintel platform is still the dominant desktop and laptop computer architecture. There have been opinions that Microsoft Windows by its natural software bloat has eaten up much of the "hardware progress" that Intel processors gave to the "Wintel platform" via Moore's law . [ 5 ] After the rise of smartphones and netbooks some media outlets have speculated predicting a possible end of Wintel dominance with more and more cheap devices employing other technologies. [ 6 ] [ 7 ] [ 8 ] Intel is investing in Linux , and Microsoft ported Windows 8 to the ARM architecture with Windows RT . In the strictest sense, "Wintel" refers only to computers that run Windows on an Intel processor. However, Wintel is now commonly used to refer to a system running a modern Microsoft operating system on any modern x86 -compatible CPU, manufactured by either Intel or AMD. [ 9 ] That is because the PC applications that can run on an x86 Intel processor usually can run on an x86 AMD processor too. In mid-October 2017, Microsoft announced that Windows 10 on Qualcomm Snapdragon is at the final stage of testing. [ 10 ] [ 11 ] [ 12 ] That would not be considered a "Wintel" . Systems running a Microsoft operating system using an Intel processor based on the Itanium or ARM architecture , despite the fact that the processor is manufactured by Intel, are also not considered to be a Wintel system.	https://en.wikipedia.org/wiki/Wintel
Winterization of oil is a process that uses a solvent and cold temperatures to separate lipids and other desired oil compounds from waxes . Winterization is a type of fractionation (also known as fractionate crystallization), the general process of separating the triglycerides found in fats and oils, using the difference in their melting points, solubility, and volatility. [ citation needed ] Winterization is an oil refinement technique commonly used in biotechnology . The process involves dissolving the extract in ethanol , then placing the mixture in a freezer to chill. The cold allows for the separation of compounds by differences in their melting and precipitation points. In the cooling process, the fats and waxes with higher melting points will precipitate out and can then be removed by filtration , centrifugation , decantation , or other separation processes. A pure, liquid oil extract is left behind, ready to be further processed for consumer use. [ citation needed ] Food products containing non-processed oils, such as fats and waxes with higher melting points, will crystallize in refrigeration temperatures. This precipitation could result in products like salad dressings separating during cold storage. Winterization is used to refine oil in salad dressings, mayonnaise , cooking oils like sunflower oil , [ 1 ] and botanical oils. [ citation needed ] Rice bran oil is one of the most commonly winterized oils, as it has a high content of waxes, fatty acids and lipids. [ citation needed ] Winterization is also used in refining biofuel , as it improves low temperature flow properties. [ 2 ] This is necessary in preventing crystallization of certain compounds in the fuel, which could cause problems with compression engines. [ 3 ] Winterization is also a common process in the cannabis industry , used to remove unwanted compounds from cannabis oil extracts. [ 4 ] Winterization often follows supercritical CO 2 extraction , for the production of cannabis oils to be used in vape pens and capsules. [ 5 ] This article related to natural gas, petroleum or the petroleum industry is a stub . You can help Wikipedia by expanding it . This chemical process -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Winterization_of_oil
In psychology , game theory , statistics , and machine learning , win–stay, lose–switch (also win–stay, lose–shift ) is a heuristic learning strategy used to model learning in decision situations. It was first invented as an improvement over randomization in bandit problems . [ 1 ] It was later applied to the prisoner's dilemma in order to model the evolution of altruism . [ 2 ] The learning rule bases its decision only on the outcome of the previous play. Outcomes are divided into successes (wins) and failures (losses). If the play on the previous round resulted in a success, then the agent plays the same strategy on the next round. Alternatively, if the play resulted in a failure the agent switches to another action. A large-scale empirical study of players of the game rock, paper, scissors shows that a variation of this strategy is adopted by real-world players of the game, instead of the Nash equilibrium strategy of choosing entirely at random between the three options. [ 3 ] [ 4 ] This game theory article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Win–stay,_lose–switch
A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, [ 1 ] by tracking the trails of gaseous ionization. [ 2 ] The technique was an improvement over the bubble chamber particle detection method, which used photographic techniques, as it allowed high speed electronics to track the particle path. The multi-wire chamber uses an array of wires at a positive dc voltage ( anode )s, which run through a chamber with conductive walls held at a lower potential ( cathode ). The chamber is filled with gas, such as an argon/methane mix, so that any ionizing particle that passes through the tube will ionize surrounding gaseous atoms and produce ion pairs, consisting of positive ions and electrons. These are accelerated by the electric field across the chamber, preventing recombination; the electrons are accelerated to the anode, and the positive ions to the cathode. At the anode a phenomenon known as a Townsend avalanche occurs. This results in a measurable current flow for each original ionising event which is proportional to the ionisation energy deposited by the detected particle. By separately measuring the current pulses from each wire, the particle trajectory can be found. Adaptations of this basic design are the thin gap, resistive plate and drift chambers. The drift chamber can also be subdivided into ranges of specific use in the chamber designs known as time projection , microstrip gas, and those types of detectors that use silicon. [ 3 ] [ 4 ] In 1968, Georges Charpak , while at the European Organization for Nuclear Research ( CERN ), invented and developed the multi-wire proportional chamber ( MWPC ). This invention resulted in him winning the Nobel Prize for Physics in 1992. The chamber was an advancement of the earlier bubble chamber rate of detection of only one or two particles every second to 1000 particle detections every second. The MWPC produced electronic signals from particle detection, allowing scientists to examine data via computers. [ 5 ] [ 6 ] [ 7 ] The multi-wire chamber is a development of the spark chamber . [ 8 ] In a typical experiment, the chamber contains a mixture of these gases: [ 2 ] The chamber could also be filled with: For high-energy physics experiments, it is used to observe a particle's path. For a long time, bubble chambers were used for this purpose, but with the improvement of electronics , it became desirable to have a detector with fast electronic read-out. (In bubble chambers, photographic exposures were made and the resulting printed photographs were then examined.) A wire chamber is a chamber with many parallel wires, arranged as a grid and put on high voltage, with the metal casing being on ground potential. As in the Geiger counter , a particle leaves a trace of ions and electrons, which drift toward the case or the nearest wire, respectively. By marking off the wires which had a pulse of current, one can see the particle's path. The chamber has a very good relative time resolution, good positional accuracy, and self-triggered operation (Ferbel 1977). [ 12 ] The development of the chamber enabled scientists to study the trajectories of particles with much-improved precision, and also for the first time to observe and study the rarer interactions that occur through particle interaction. If one also precisely measures the timing of the current pulses of the wires and takes into account that the ions need some time to drift to the nearest wire, one can infer the distance at which the particle passed the wire. This greatly increases the accuracy of the path reconstruction and is known as a drift chamber . A drift chamber functions by balancing the loss of energy from particles caused by impacts with particles of gas with the accretion of energy created with high-energy electrical fields in use to cause the particle acceleration. [ 13 ] Design is similar to the multi-wire proportional chamber but with a greater distance between central-layer wires. [ 8 ] The detection of charged particles within the chamber is possible by the ionizing of gas particles due to the motion of the charged particle. [ 14 ] The Fermilab detector CDF II contains a drift chamber called the Central Outer Tracker . [ 15 ] The chamber contains argon and ethane gas, and wires separated by 3.56-millimetre gaps. [ 16 ] If two drift chambers are used with the wires of one orthogonal to the wires of the other, both orthogonal to the beam direction, a more precise detection of the position is obtained. If an additional simple detector (like the one used in a veto counter) is used to detect, with poor or null positional resolution, the particle at a fixed distance before or after the wires, a tri-dimensional reconstruction can be made and the speed of the particle deduced from the difference in time of the passage of the particle in the different parts of the detector. This setup gives us a detector called a time projection chamber ( TPC ). For measuring the velocity of the electrons in a gas ( drift velocity ) there are special drift chambers, velocity drift chambers , which measure the drift time for a known location of ionisation.	https://en.wikipedia.org/wiki/Wire_chamber
Wire rope spooling technology is the technology to prevent wire rope getting snagged when spooled , especially in multiple layers on a drum. Ever since the development of wire rope , comprising multiple wire strands, spooling the wire has presented technical challenges. When wrapped in multiple layers, the upper layers have a tendency to crush the lower layers, while the lower layers have a tendency to pinch upper layers. The rubbing of rope against rope also has a tendency to cause wear. These problems were addressed by Frank L. LeBus Sr., a supplier of drilling equipment to the oilfields of Texas, USA, who in 1938, patented the use of a groove bar on hoisting drums to guide the spooling of rope. Grooved shape steel segments were simply welded or screwed to existing plain steel drums. [ 1 ] Ever since then, drum groovings have been widely used to guide the spooling of wire rope onto and off winch drums. Introducing a continuous helical groove onto the drum, like the thread of a screw, provides a way to guide the rope when spooling onto or off a drum. However this has been shown to work effectively only when the rope is wrapped in a single layer. When the rope is wrapped in multiple layers, problems remain. Frank LeBus introduced a grooving pattern that put the groove parallel to the flanges of the drum, except for a single slanted section across the drum face to act as crossover point, moving the rope along by the width of the groove with every revolution. While the Lebus family business continues to produce this equipment today, their patents have expired. The Lebus name, however, is a registered trademark owned by the Lebus family business so the term "Lebus Drum" specifically refers to products of Lebus International. The multilayer wire rope spooling system has undergone continuous refinement over the years and adapted for any application where long lengths of steel wire ropes must be wrapped in multiple layers quickly and smoothly. Examples include: With the parallel groove system, rope wear is considerably reduced in multilayer spooling. When the first layer has filled the drum, the second layer then travels back across the drum with each wrap of rope sitting precisely along the groove of two wraps of the first layer. With parallel grooving it is possible to calculate the exact forces that the rope imposes on the drum because the spooling is controlled. Cross winding is reduced to approximately 20% of the circumference of the drum, and 80% remains parallel to the flanges in the inner layer rope groove. This parallel grooving evenly distributes the load between the individual layers and has been shown to increase substantially – by more than 500%, tests have shown – the life of the wire rope. The system has been used to mount ropes up. In offshore applications, huge lengths of rope are often housed on drums. The anchor winches on Saipem's Semac 1 pipe laying barge, for example, each hold 2,800 metres of 76mm (3 inch) diameter wire rope in 14 layers. Saipem's Castorone, the world's largest pipe laying vessel uses a wire rope that is 3,850m long and 152mm in diameter. It weighs 420t. The rope is pulled by capstan and stored on a massive Rema traction winches that feature the parallel grooving system, with an approximately back tension of 40t on the capstan. To maximise the benefits of the parallel grooving system, certain operating conditions are required. These include: Every system should be tailored to the application for which it is used. The groove pattern is engineered to suit the rope's length, diameter and construction type. In any multi-layer spooling application it is important that when the rope is first installed on the drum, it is done so under tension to avoid any slack on inner layers that can be crushed or nicked against the groove walls by outer layers. The fleet angle is defined as the largest angle of the rope between the first sheave and the drum flange, relative to the centre line of the drum. With all type of drums, the rope is subject to a fleet angle which impacts on its behaviour and affects lifespan. Fleet angle should be between 0.25° and 1.25°, depending on the rope construction. The fleet angle can be varied by moving the first sheave closer to or further away from the drum. If the sheave is too close to the drum, the fleet angle will be greater than 1.25°; if it is too far away, the fleet angle will be less than 0.25°. Sometimes it is not possible to achieve the optimum fleet angle. Where there is no space to rig a sheave the requisite distance from the drum, two additional spooling devices are available. One is a fleet angle compensator, which is driven automatically by the rope tension. The other is a level winder that is mechanically driven. Both offer a solution to guide the cable along the drum between flanges, but each has its advantages and disadvantages. The fleet angle compensator (FAC) is driven by the movement of the wire rope as it goes through the crossover sections of the drum. As the rope winds or unwinds, the FAC shaft automatically oscillates slowly, allowing its sheave to slide back and forth across the shaft to maintain an optimum fleet angle and guide the rope smoothly onto the drum. Level winders can be hydraulically or electrically driven and computer controlled, or they can be simple mechanical devices. A mechanical level winder comprises a main shaft (the lead screw) with helical screw grooving along which the rope feeder travels. The rope feeder housing includes two vertical roller bars and one horizontal roller, or alternatively a wire rope sheave. The lateral movement of the housing is generated by a chain drive sprocket ratio between drum and lead screw, as shown in the image. The automatic level winder fitted is designed and engineered to be compatible with the grooving on the drum. Alternatively, a sheave can be integrated and installed within the housing frame. In this case, the system can be set up anywhere around the drum. Oceanographic installations that spool rope up to 46 layers have demonstrated that level winders give synchronized and controlled spooling in the harshest, most testing conditions. Grooving systems for multilayer spooling can be carved onto steel shells that are mounted onto old drums, by either bolting or welding, as an outer sleeve. Called split sleeves, they can be retrofitted onto old drums or mounted on new drums to allow a future change of application.	https://en.wikipedia.org/wiki/Wire_rope_spooling_technology
Wired communication refers to the transmission of data over a wire -based communication technology ( telecommunication cables ). Wired communication is also known as wireline communication . Examples include telephone networks , cable television or internet access , and fiber-optic communication . Most wired networks use Ethernet cables to transfer data between connected PCs. Also waveguide (electromagnetism) , used for high-power applications, is considered wired line. Local telephone networks often form the basis for wired communications and are used by both residential and business customers in the area. Many networks today rely on the use of fiber optic communication technology as a means of providing clear signaling for both inbound and outbound transmissions and are replacing copper wire transmission. Fiber optic technology is capable of accommodating far more signals than copper wiring while still maintaining the integrity of the signal over longer distances. Alternatively, communication technologies that don't rely on wires to transmit information (voice or data) are considered wireless , and are generally considered to have higher latency and lower reliability. The legal definition of most, if not all, wireless technologies today or " apparatus, and services (among other things, the receipt, forwarding, and delivery of communications) incidental to such transmission " are a wire communication as defined in the Communications Act of 1934 in 47 U.S.C. §153 ¶( 59 ). This makes everything online today and all wireless phones a use of wire communications [ 1 ] by law whether a physical connection to wire is visible or is not. The Communications Act of 1934 created the Federal Communications Commission to replace the Federal Radio Commission . If there were no real wired communications today, there would be no online and there would be no mobile phones. Satellite communications would be the only current technology considered wireless . [ clarification needed ] In general, wired communications are considered to be the most stable and best of all types of communications services. They are relatively impervious to adverse weather conditions in comparison to wireless communication solutions. These characteristics have allowed wired communications to remain popular even as wireless solutions have continued to advance. This article related to telecommunications is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wired_communication
During World War II , the German Army relied on a diverse array of communications to maintain contact with its mobile forces and in particular with its armoured forces. Most of this equipment received the generic prefix FuG for Funkgerät , meaning "radio device". Occasionally the shorted Fu designation were used and there were exceptions to both these systems. Number ranges were not unique across the services so sometimes different equipment used by different services had the same FuG prefix. This article is a list and a description of the radio equipment. Fug 1 : Also known as Torn.E.b And Pack Receiver b. A Medium-wave receiver it operated in the 0,1 to 7,095 kHz frequency range. Repackaged for use in several other receivers and transceivers. FuG 2 : A high-band HF /low-band VHF receiver. Also known a USW receiver c1. It operated in the 27,000 to 33,300 kHz (27 MHz - 33.3 MHz) range (same frequency range used by modern 27MHz CB radio systems) The FuG 2 was never used on its own but as an additional receiver in command tanks and relay devices. It was usually installed in section leader and company commanders' vehicles, to allow them to listen on one frequency while transmitting and receiving on another. As it operated on the same band as the FuG 5 it allowed them, for example, to listen to the regimental command net while talking to the subordinate units at the same time. Matching the transmitters that operated in this frequency range, this receiver provided for 50 kHz channel steps in the 27.000 MHz to 33.300 MHz range for a total of 125 available channels. FuG 3 : A low-band VHF receiver. It operated in the 42–47.8 MHz range. Repackaged as FuG 3 neu for use with motorcycle troops. FuG 4 : A medium-wave receiver used in command tanks. It operated in the 1,130 to 3,000 kHz frequency range. It was used with the same antenna as the Fug 8. It was usually used for communication with a Fug 8 in the same installation. (Fug 8 + Fug 4) FuG 5 : A high-band HF/low-band VHF transceiver. It operated in the 27,000 to 33,300 kHz (27-33.3 MHz) frequency range with a transmission power of 10 Watts. This equipment provided for 125 radio channels at 50 kHz channel spacing. It was usually used with a two-metre antenna. Was present in almost all German tanks and some other vehicles. Was the standard kit for tank-to-tank communication within platoons and companies. Range was approx 2–3 km when using AM voice and 3–4 km when using CW Reworked to produce the FuG 5 (Luft) variant which was used for air-to-ground communication until replaced with the FuG 7 . FuG 6 : A high-band HF/low-band VHF transceiver. It operated in the 27,000 to 33,300 kHz (27-33.3 MHz) frequency range with a transmission power of 20 Watts. It was usually used with a two-metre antenna. It was used by armoured observation posts. These were usually early-model tanks with some of their armament removed and replaced by equipment for artillery observers. It was used by the observers to communicate with the armoured unit leaders via their Fug 5 radios. Main advantage over the FuG 5 was greater range. Range was approx 4–6 km when using AM voice and 6–8 km when using CW. Comparable to the American SCR-508 tank radio, which covered a similar frequency range (20-27.9 MHz) at 25 watts and the SCR-608 artillery variant (which operated in the 27-38.9 MHz frequency band) The major difference between German Army tank sets and US Army tank and artillery sets was the American use of FM for the high-HF/low-VHF bands. FuG 7 : A VHF transceiver (receiver/transmitter) used in command tanks. It operated in the 42,000 to 48,300 kHz (42-48.3 MHz) frequency range with a transmission power of 20 Watts. It was usually used with a 1.4 metre antenna. It was matched with the Luftwaffe transceiver Fug 17 in ground support operations. It was used for CAS operations, though these became rare after late 1944 with the result that many command tanks with this equipment fitted were converted to other roles. Ground-to-air range 60 km AM voice to 80 km CW. FuG 8 : A medium-wave transceiver (receiver/transmitter) used in command tanks. It operated in the 1,130 to 3,000 kHz frequency range with a transmission power of 30 Watts. It was used with various antenna ranging from 1.8 to 9-metre antenna. It was used for communication back to the regimental command post. Range 25 km AM voice to 140 km CW using the nine-metre antenna, the station had to be stopped to use this antenna. FuG 9 : A transceiver, operated in the 0.1 - 7.1 MHz (100 kHz - 7100 kHz) range. FuG 10 : A medium-wave transceiver (receiver/transmitter) used in command tanks. It operated in the 1,130 to 3,000 kHz frequency range with a transmission power of 30 Watts. It was used with a frame antenna on various reconnaissance units. Range 10 km AM voice to 40 km CW. FuG 11 : A medium-wave transceiver (receiver/transmitter) used in command tanks. It operated in the 1,130 to 3,000 kHz frequency range with a transmission power of 100 Watts. Used at the regimental command post. Range 70 km AM voice to 200 km CW. FuG 12 : A medium-wave transceiver (receiver/transmitter) used in command tanks. It operated in the 1,130 to 3,000 kHz frequency range with a transmission power of 80 Watts. It was used with a two-metre antenna. Reconnaissance units later in the war. FuG 13 : A Fug 6 with two receivers rather than one. FuG 14 : Multi-radio setup consisting of several separate radios. FuG 15 : A HF receiver. It operated in the 23,000 to 24,950 kHz (23-24.95 MHz) frequency range. It was matched with transceiver Fug 16 for use with Sturmartillerie (self-propelled artillery). FuG 16 : A HF transceiver (receiver/transmitter) used in the command vehicles of Sturmartillerie units. It operated in the 23,000 to 24,950 kHz (23-24.95 MHz) frequency range with a transmission power of 10 Watts. It was usually used with a two-metre antenna. Range 2 km AM voice to 4 km CW. FuG 17 : Designation for a Torn Fu H transceiver. Fug 18 : Group of high HF band - low VHF / mid band VHF radios covering 25 MHz - 77.1 MHz Fug 19 : A HF transceiver operating in the range 3 - 7.5 MHz. In some command units. Fug 20 : A 0.1 - 7.1 MHz receiver paired with a 1.1 - 3 MHz transmitter. Fug 21 : A 0.1 - 10 MHz receiver paired with a 2.5 - 7.5 MHz transmitter. Fug 24 : A 0.1 - 7.1 MHz receiver paired with a 3 - 7.5 MHz transmitter. Fug 25 : A 2.5 - 27.5 MHz receiver paired with a 3 - 16.6 MHz transmitter. FuSpr.a : A high-band HF transceiver. It operated in the 24.1 to 25 MHz (24100 to 25000 kHz) frequency range with a transmission power of 5 Watts. It was used with antenna of either 1.4 to 2.0 metres antenna. It was used for by reconnaissance elements for intercommunication. Range 5 km AM voice. [ 1 ] FuSpr.d : A mid-band HF/high band HF transceiver. It operated in the 23.11 to 24.01 MHz (24100 to 25000 kHz) frequency range with a transmission power of 5 Watts. It was used with antenna of either 1.4 to 2.0 metres antenna. Used by anti-tank units. FuSpr.f : A mid-band HF transceiver. It operated in the 19,990 to 21,470 kHz (19.99-21.47 MHz) frequency range with a transmission power of 5 Watts. It was used with antenna of either 1.4 to 2.0 metres antenna. It was used for by observation teams of the Sturmartillerie to communicate with artillery units. Range 5 km AM voice. [ 1 ] The German-army-issued infantry radios in two main series. The "Backpack" or Torn (Tornister) series and the field or Feld series. Torn.Fu.a : A HF transceiver. It operated in the 3–6.67 MHz frequency range. 2 Watt output AM voice and CW Torn.Fu.b : A HF transceiver. It operated in the 3-5 MHz frequency range. 0.7 Watt output AM voice and CW. Formed the base design of other units. Used by the infantry at the regimental and battalion level. Not intended to be used on the move. Torn.Fu.c : A HF transceiver. It operated in the 1.5-2.6 MHz frequency range. Otherwise identical to Torn.Fu.b . Used by artillery observers. Torn.Fu.d2 : A VHF low band transceiver. It operated in the 33.8-38 MHz frequency range. 1.5 Watt output AM voice and CW. Range approximately 10 km with Cw and 3 km with voice. Used by the infantry. A common infantry set used for voice radio nets . Could be used on the move with one man carrying the transmitter/receiver and the other the battery/power supply and handset. A cable linked the two men together. Comparable in range, performance and frequency band used to the VHF FM SCR-300 (BC-1000) infantry backpack radio set (40 MHz - 48 MHz, FM voice) used by US and Allied forces. [ 2 ] Torn.Fu.f : A HF transceiver. It operated in the 4.5-6.67 MHz frequency range. 0.7 Watt output AM voice and CW. Panzergrenadier units. Identical to Torn.Fu.b with exception of frequency range. [ 2 ] Torn.Fu.g : A HF transceiver. It operated in the 2.5-3.5 MHz frequency range. 0.5 Watt output AM voice and CW. Used at the battalion to company level of the Panzergrenadier. Some command and reconnaissance units had this infantry transceiver to allow then to talk to Panzergrenadier units. [ 2 ] Torn.Fu.h : A HF transceiver. It operated in the 23-28 MHz frequency range. 0.6 Watt output AM voice. Sturmartillerie units. Torn.Fu.i : A HF transceiver. It operated in the 1.87 - 3 MHz frequency range. Replacement for Torn.Fu.f . [ 3 ] Torn.Fu.k : A HF transceiver. It operated in the 4.5-6.67 MHz frequency range. 1 Watt output AM voice and CW. Replacement for Torn.Fu.g . [ 3 ] Feldfu.a1 : 120-156 MHz infantry, a VHF transceiver. 0.15 Watt (150 mW) output AM voice and CW. Range 1.5 km. Feldfu b : 90-110 MHz Used by the infantry used in two versions. 0.15 Watt (150mW) output AM voice and CW. The b version was used by the infantry until they changed to the 'c' model radio in another band. This unit was also used by motorcycle troops in the first half of the war. Thereafter version b1 was used by the Pioneers. Later a simplified version (b2), of lower power (.12w), was used by the Panzergrenadiers. [ 3 ] Feldfu b1 : Pioniere VHF radio 90 MHz - 110 MHz range 1.5 km. Feldfu b2 : Panzergrenadier only two tubes, no AF tube Rv2,4P700 Feldfu c : 130 MHz - 160 MHz infantry. 0.15 Watt output AM voice and CW. Infantry. Range 1.5 km. Feldfu d : VHF low band 32 MHz - 38 MHz Artillery Observers. 0.15 Watt output AM voice and CW. Infantry. Range 1.5 km. Feldfu f : 28 MHz - 33.0 MHz Panzergrenadier. Could interwork with the Fug 5 of the armour. Feldfu h : 23.1 - 28.0 MHz Assault Guns and Sturmartillerie KL.Fuspr.d : A VHF transceiver. It operated in the 32-38 MHz frequency range. Single-unit "walkie-talkie" system. Used by artillery forward observers. From 1936 the German forces started deploying a range of communication links using UHF frequencies to form a point-to-point mesh communication network. During the war this was extended to cover the majority of the occupied areas or Europe and North Africa. Both the army and the air force made use of the same equipment. The units of the T series were "backpack"-style mobile equipment. The K series were truck mobile units using a range of masts up to approximately 11 m tall. The G series were still mobile but were intended to form more of a backbone for communications and were intended to remain in place for longer periods than the K. They again used a series of masts up to 50 m high. Depending on the set a range of communication facilities were available consisting of voice and/or teletype and Hellscriber. Range was line-or-sight so the ranges reported here were assuming the antenna could "see" one another. [ 4 ] [ 5 ] DMG 2 T : Pack unit, operating on the 475 - 525 MHz band, single channel voice or 800 character-per-second teletype. Range up to 50 km. Tripod mast or 11 m mast. Transmission power 0.15 watt. Power battery. DMG 3 K : Truck-mounted. Operating on the 475 - 525 MHz band, two channels. Channel 1, one voice channel or one 800 CPS teletype. Channel 2 6000 CPS teletype. Range up to 50 km. Mast or tower. Power 220 V AC 50 Hz. Michael 2 B - DMG 4a K : Truck-mounted. Operating on the 500 - 560 MHz band, two channels. Channel 1, voice or 2400 CPS teletype. Channel 2 8000 CPS teletype. Range up to 100 km. Tower up to 50 m. Transmission power 0.4 Watts. Power 220 V AC 50 Hz 250 VA. Michael 2 R - DMG 5 K : Truck-mounted. Operating on the 502 - 555 MHz band, two channels. Channel 1 Voice or 5500 CPS teletype or three channels teletype. Channel 2 8000 CPS teletype. Transmitter power 1 watt. Range up to 50 km. Mast or tower. Power 22 V AC 50 Hz 300 VA. Rudolf - DMG 3 G : 'Heavy' link. Operating on the 600 - 650 MHz band, two channels. Channel 1 control channel voice, Channel 2 nine voice channels or p x 3 Teletype. Range up to 100 km. Tower up to 50 m. Transmission power 3.5 watts. Power 220 V AC 50 Hz 680 VA. Stuttgart - FuG D 3 : Development item, possible none deployed. Operating on the 1250 - 1390 MHz band, two channels. Range up to 100 km. Tower up to 50 m. DM 43 : Development item, possible none deployed. Operating on the 2000 - 2100 MHz band. No other details available	https://en.wikipedia.org/wiki/Wireless_Communications_of_the_German_Army_in_World_War_II
The Wireless Gigabit Alliance [ 1 ] (WiGig Alliance) [ 2 ] was a trade association that developed and promoted the adoption of multi- gigabit per second speed wireless communications technology " WiGig " operating over the unlicensed 60 GHz frequency band . The alliance was subsumed by the Wi-Fi Alliance in March 2013. [ 3 ] The formation of the WiGig alliance to promote the IEEE 802.11ad protocol was announced in May 2009. [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] The completed version 1.0 WiGig specification was announced in December 2009. [ 10 ] [ 11 ] [ 12 ] [ 13 ] [ 14 ] In May 2010, WiGig announced the publication of its specification, the opening of its Adopter Program, and the liaison agreement with the Wi-Fi Alliance to cooperate on the expansion of Wi-Fi technologies. [ 15 ] [ 16 ] In June 2011, WiGig announced the release of its certification-ready version 1.1 specification. [ 15 ] Among the companies that comprise the board of directors are: Contributor members include: Ali Sadri is the president and chairman of the board of WiGig Alliance, and also founded the movement. [ 20 ] Sadri directs all activities throughout the alliance, from leading the board of directors to providing support for the technical working groups. [ citation needed ] The Wireless gigabit alliance set about its task for creating faster and more efficient communications technology in 2007. [ citation needed ] Their idea was to set about creating wirelessly interconnected home entertainment and office devices, like PCs, tablets, smartphones and displays, entirely removing the need for wires. They also wanted devices to be constantly connected and ready to transfer. Thus eliminating the need to have both a laptop and a tablet, as a device could connect straight to a display. In May 2009, the alliance announced something, [ clarification needed ] and WiGig 1.0, announced in December of the same year. In 2010, WiGig and the Wi-Fi alliance announced a cooperation agreement. The agreement combined 60 GHz with traditional Wi-Fi networking that extended the range at slower speeds and helped signals to go through walls to cover entire homes. On November 3, 2010, the WiGig Alliance and the Video Electronics Standards Association (VESA) announced an association to define the next generation standard wireless display technology. VESA and WiGig Alliance agreed to share technology specifications to develop multi-gigabit wireless Display Port capabilities. The official standard was published by the Standards Association of the IEEE in December 2012 as IEEE 802.11ad-2012 as an amendment to the overall IEEE 802.11 standard family. [ 21 ] In January 2013, after more than two years of collaboration, the Wireless Gigabit Alliance announced it would merge with the Wi-Fi Alliance . The merger was finalized in March. [ 3 ] Although no longer a separate organization, the WiGig technology kept its name, with the Wi-Fi Alliance planning to jointly certify both devices in late 2013. On September 9, 2013, a statement revealed that the WiGig protocol would be used in a new wireless version of USB through a deal between the Wi-Fi Alliance and the USB Implementers Forum. The Wireless USB standard would use existing USB 2.0 and 3.0 drivers. The Wi-Fi alliance transferred WiGig wireless transmission technology to the USB Implementers Forum as it is expected that WiGig certified products will implement USB functionality. [ citation needed ] On November 3, 2010, WiGig Alliance announced the WiGig version 1.0 A/V and I/O protocol adaptation layer (PAL) specifications. [ 15 ] The application specifications have been developed to support specific system interfaces including extensions for PC peripherals and display interfaces for HDTVs, monitors and projectors. WiGig Display Extension WiGig Bus Extension and WiGig Serial Extension. The WiGig Bus Extension (WBE) was available to members in 2011. [ 22 ] On May 10, 2010, the Wi-Fi Alliance and WiGig Alliance announced a cooperation agreement for multi-gigabit wireless networking. The Wi-Fi Alliance and the WiGig Alliance shared technology specifications for the development of a Wi-Fi Alliance certification program supporting Wi-Fi operation in the 60 GHz frequency band. [ 23 ] [ 24 ] [ 25 ] On November 3, 2010, the WiGig Alliance and the Video Electronics Standards Association (VESA) announced a liaison for standard wireless display technology. VESA and WiGig Alliance agreed to share technology specifications to develop multi-gigabit wireless DisplayPort capabilities and create a certification program for wireless DisplayPort products. [ 26 ] On June 28, 2011, the WiGig Alliance announced becoming an Adopter of HDMI Licensing, LLC to further provide WiGig Display Extension (WDE) support for HDMI mapping. WDE is the only 60 GHz specification that defines a framework to connect to DisplayPort monitors and HDMI TVs, enabling applications such as the wireless transmission of compressed or uncompressed video. [ 15 ] [ 27 ] WiGig competes with WirelessHD in some applications. WirelessHD transmits in the same 60 GHz band used by WiGig.	https://en.wikipedia.org/wiki/Wireless_Gigabit_Alliance
Wireless HDMI is the wireless transmission of high-definition audio and video signals between devices, using unlicensed radio frequencies like 5 GHz, 60 GHz, or 190 GHz. This technology eliminates the need for an HDMI cable , allowing users to transmit signals wirelessly between the component device and the display device. Wireless HDMI converts the HDMI cable signal into a radio frequency which is broadcast across the wireless spectrum . This allows for video source and display device to be in different rooms, without the need for cables. The technology emerged in the early 2000s. Wireless HDMI systems emerged in the early 2000s. In 2006, TZero Technologies and Analog Devices created a wireless HDMI interface consisting of a transmitter and receiver, expected to cost less than HDMI cable. At CES in 2007, Philips debuted the first publicly available wireless HDMI system. Wireless HDMI systems have steadily grown in popularity. Supporters of this technology claim that it's beneficial for the use of projectors – citing its low cost compared to custom projector mounting solutions, as well as its ease of use. [ 2 ] However, with the introduction of streaming sticks such as Amazon's Fire TV and Google's Chromecast into the market, users are also opting for this option. [ 2 ] Streaming sticks come with their own remotes and user interfaces, allowing them to function as an all-in-one solution, something wireless HDMI systems cannot do. [ 2 ] Despite the advent of streaming sticks, there are still developments in the area of wireless HDMI technology. For example, in 2020, a patent was sought by Shenzhen Lenkang Technology for a new form of Wireless HDMI system. [ 3 ] This new device is to be smaller, utilizing a pin layout rather than a traditional power supply. [ 3 ] The HDMI transmitter would be able to receive power through a custom HDMI interface, eliminating the need for a separate power supply, and reducing the size of the unit. [ 3 ] IP based Cables for mobile equipment	https://en.wikipedia.org/wiki/Wireless_HDMI
The Wireless Infrastructure Association ( WIA ), formerly known as PCIA, is an American trade association for wireless providers and companies that build cell phone towers, rooftop wireless sites, [ 1 ] and other facilities that transmit wireless communication signals. The Washington Post described the industry as "the people who build all those cell towers so you can actually make those calls, download that data." [ 2 ] These technologies are collectively referred to as "wireless telecommunications infrastructure." [ 3 ] [ 4 ] [ 5 ] Examples of companies that are members of WIA include American Tower , Ericsson, Graybar , JMA Wireless , Qualcomm , and SBA Communications. [ 6 ] [ 7 ] In all, member companies own and run more than 125,000 towers and antennas in the U.S. [ 8 ] WIA advocates for a variety of issues before the federal government, on topics such as broadband deployment (the act of building wireless broadband infrastructure in the United States), utility pole attachment (adding wireless signal components to utility poles that already exist), wireless network resiliency, public safety, and wireless competition. [ 9 ] WIA hosts an annual conference and trade show called the Connectivity Expo, also known as Connect (X). [ 10 ] Previously WIA hosted the Wireless Infrastructure Show. [ 11 ] The Chairman of WIA is Jeffrey A. Stoops, president and chief executive officer of SBA Communications Corp. [ 12 ] The previous chairman was David Weisman, president of InSite Wireless Group, which was an independent tower company. American Tower announced an agreement to buy InSite's assets in late 2020 for approximately $3,5 billion. [ 13 ] Jonathan Adelstein , a former FCC commissioner , is the president and CEO of WIA. [ 14 ] Adelstein worked in public service for 25 years before joining WIA. [ 3 ] In February 2014, Adelstein told C-SPAN that his goal was to bring wireless connectivity to everyone in the United States. [ a ] [ 16 ] Tim House is WIA's Executive Vice President. Before WIA, House worked in consumer product marketing at Discovery Communications. [ 17 ] WIA was founded in 1949. The focus of the group has shifted as technologies have advanced. At various times throughout WIA's history, it has focused on land mobile radio, paging, messaging, personal communications services, and tower and antenna siting. [ 18 ] In 2012, WIA submitted an amicus curiae brief in the U.S. Supreme Court case Arlington v. FCC . WIA argued in support of the FCC in the case, arguing that local delays in approval of broadband projects are a national problem. The amicus curiae brief cited evidence that over 3,300 wireless service facility siting applications were pending before local jurisdictions throughout the country, and that around 180 of those applications had been pending for over three years. [ 8 ] In 2012, Congress passed and President Barack Obama signed the Middle Class Tax Relief and Job Creation Act. The law included a provision related to the wireless infrastructure industry. Specifically, section 6409(a) of the law orders states and local governments to approve requests made by companies to collocate [ b ] , remove or replace transmission equipment on existing wireless towers or base stations. The law included an exception: if the action substantially changes the physical dimensions of the tower or base station, then the law's protection doesn't apply. [ 20 ] The provision and the authority it prescribed is described by the wireless industry as "collocation-by-right". [ 21 ] In 2013, WIA submitted comments to the FCC that expressed support in speeding up broadband deployment. WIA helped Congress write legislation that funded broadband deployment. WIA had asked Congress to include infrastructure providers in the list of eligible recipients of federal broadband funding. WIA influenced members of the congressional committees that funded the $4.7 billion Broadband Technology Opportunities Program (BTOP) to make eligible wireless carriers, backhaul providers, and tower companies for funds. [ 23 ] In 2013, Cisco, American Tower, Dynis, and WIA created a program called Warriors 4 Wireless. The organization helps military veterans train and apply for jobs at wireless companies. The program's stated goal is to place 5,000 veterans in jobs by 2015. WIA has pledged money to the program. [ 24 ] [ 25 ] WIA advocated an effort passed by the FCC commonly referred to as The "5G Upgrade Order," which made key clarifications for wireless deployment. The Order: WIA has been the leading voice in lobbying Congress to include wireless for funding eligibility in its landmark infrastructure bill. The bipartisan-passed legislation will provide $65 billion for broadband deployment and access. This legislation will promote wireless infrastructure deployment, with a priority on unserved communities. WIA helped convince Congress and the Administration to provide agencies with the needed flexibility to allow all broadband technologies, including mobile and fixed wireless, the opportunity to compete for funding. The all of-the-above broadband strategy, as pursued by WIA, will help close the digital divide and win the race to 5G. [ 27 ] One of the main issues facing the wireless infrastructure industry is related to federal vs. local oversight of wireless infrastructure activity. In a February 2014 article in National Law Review , Washington telecommunications attorneys Dave Thomas and Douglas A. Svor explained the issue and the battle played out between the wireless industry and local governments. In their article, Thomas and Svor state that spectrum and infrastructure serve as the most important aspects of federal communications laws in terms of being good for the economy and American competitiveness. For decades, the FCC has worked to make sure that critical communications infrastructure can get built with as little hassle as possible. In April 2014, the FCC proposed to simplify the regulatory review process for wireless facilities. These facilities include DAS and small cells (see Small cells and HetNet Forum below for more information). Small cells are built smaller than traditional cells that are typically fixed to large wireless antenna towers. Infrastructure companies attach small cells to utility poles, street light poles, and even traffic lights. The wireless industry has supported the FCC's work in the areas mentioned above, while local governments have typically been opposed. Thomas and Svor wrote: [ 28 ] Industry's universal support for the FCC's proposals has been matched by local government's hostility towards them. State and local governments view the measures as an unwarranted - and unconstitutional - federal incursion into state and local authority. HetNets, short for "Heterogeneous Networks", are a combination of technologies that make quality wireless broadband possible. [ 43 ] According to international communications company Ericsson, heterogeneous networks help wireless customers enjoy activities that require a large amount of data, such as watching streaming videos, uploading photos and using cloud storage services . HetNets use both radio and cellular technologies. [ 44 ] To advocate for deployment of HetNet, WIA runs a membership forum called the HetNet Forum. The purpose of the forum is to advance the development of heterogeneous networks in the United States, as well as to push policies related to distributed antenna systems (DAS), [ d ] small cells, and fiber backhaul. [ e ] [ 47 ] Several major U.S. wireless carriers, such as AT&T, T-Mobile and Verizon Wireless, serve as governing members of the forum. [ 43 ] Prior to April 2013, the HetNet Forum had been called the DAS Forum. WIA changed the name to accommodate a growing membership that represented a more diverse group of technologies. Instead of running a forum focusing only on DAS, WIA expanded the forum to focus on several technologies such as microcells, picocells, Wi-Fi and remote radio units, in addition to DAS. [ 48 ] Other trade associations, such as the Small Cell Forum, have competed with WIA for members from the small cell industry. [ 49 ] In 2014, Senator Al Franken criticized the "revolving door" hiring placement of former FCC commissioners. Specifically, Franken criticized the hiring of FCC Commissioner Meredith Baker by Comcast. Franken did not mention WIA in his remarks, but an OpenSecrets.org article covering the remarks mentioned the hiring of former Commissioner Jonathan Adelstein by WIA. [ 50 ] Official Website	https://en.wikipedia.org/wiki/Wireless_Infrastructure_Association
Established in 1996, the Wireless Innovation Forum is a non-profit " mutual benefit corporation " dedicated to advocating for spectrum innovation and advancing radio technologies that support essential or critical communications worldwide. Forum members bring a broad base of experience in Software Defined Radio , Cognitive Radio and Dynamic Spectrum Access technologies in diverse markets and at all levels of the wireless value chain to address emerging wireless communications requirements. The forum acts as a venue for its members to collaborate to achieve these objectives. The Wireless Innovation Forum was founded in 1996 originally as "The Modular Multifunction Information Transfer System Forum". [ 1 ] The organization was created at the request of the US military services (led by the Air Force) as an industry association focused on advancing the development of software radio. In 1996, the Forum formed the Mobile Working Group to develop software specifications and standards supporting ground mobile radios. [ 2 ] [ 3 ] The Forum published its first technical report in 1997, outlining the current state of the art in software defined radio. [ 4 ] This document included a reference application framework for software defined radios, referred to as the Software Radio Architecture, that was developed based on the existing SPEAKeasy Architecture . [ 5 ] The late 1990s, also saw the initial meeting between the Forum and what later became the Joint Tactical Radio System . [ 6 ] In 1998, the Modular Multifunction Information Transfer System Forum changed its legal name to The Software Defined Radio Forum and began doing business with a broader focus on commercial and international participation. [ 7 ] The Forum created three new internal groups — Markets and Regulatory Committees and the Base Station Work Group. Also, the Forum published a revised technical report. [ 8 ] In 2001, the Forum contracted with Communications Research Centre Canada to provide a Software Communications Architecture (SCA) Reference Implementation (SCARI-Open). [ 9 ] The Forum also made filings with the United States Federal Communications Commission that helped form their public rule making on software defined radio. [ 10 ] [ 11 ] In 2002, the Forum hosted its first Technical Conference and Product Exposition, which has become an annual event with the presentation of technical papers along with tutorials, workshops and demonstrations. [ 12 ] In 2004 and 2005, the Forum reorganized to support its members in exploring technologies that extend beyond IT. A key part of this reorganization was the formation of the Cognitive Radio Work Group, which worked to support IEEE P1900.1 in defining standard definitions for Software Defined and Cognitive Radio and to establish a reference architecture for a cognitive radio system. [ 13 ] Between 2004 and 2010, the Forum signed memorandums of understanding with multiple international groups to allow collaboration in areas of mutual interest. These groups included the European End to End Efficiency Program, IEICE in Japan , IEEK in Korea , IEEE Standards Association , JTRS and the European Science Foundation . MOUs with a number of organizations continue to the present day. [ 14 ] In 2007, the Forum initiated the Smart Radio Challenge, a worldwide competition in which student engineering teams design, develop and test technologies that address relevant problems in the advanced wireless market. [ 15 ] In late 2009, the Software Defined Radio Forum was renamed the Wireless Innovation Forum, reflecting the fact that many of the projects undertaken by its members had expanded to include Cognitive Radio, Systems of Systems, Ad Hoc Networks, and Dynamic Spectrum Access Technologies . [ 16 ] In addition, the Forum restructured to established separate “Commercialization Committees” focused on establishing “an ecosystem of vendors providing interoperable hardware and software radio components to drive the economies of scale that will ultimately reduce the costs of development, production and maintenance of wireless systems, while at the same time speeding time to market and time to deployment”. [ 17 ] These committees are managed by the Forum's elected officers, which include the chair, vice chair, technical director, the chairs of the committees, the secretary, and the treasurer according to the Forum's bylaws ( https://www.wirelessinnovation.org/Bylaws ). The Forum is organized around three Commercialization Committees and one Technology Committee( https://www.wirelessinnovation.org/projects-committees ), whose responsibilities are summarized as follows and presented in the order in which they were formed: The Software Defined Systems Committee was originally created as the Coordinating Committee for International SCA Standards. This Committee was formed as a Commercialization Committee in 2010, and from 2010 to 2014, the members of the Committee worked with JTNC in the creation of what is now SCA 4.1 and the establishment test procedures for the SCA 4.1 standard. [ 18 ] This activity culminated in 2015 with the endorsement by the Forum of SCA 4.1 as “a preferred software architecture for software defined radios”. [ 19 ] In parallel with the SCA 4.1 effort, the Committee began working to harmonize SCA application programming interfaces [ 20 ] with the emerging European Secure Software Radio (ESSOR) architecture, [ 21 ] [ circular reference ] following the endorsement of ESSOR’s “Three Basket Approach”. [ 22 ] A key element of this support was the development of “Facility Standards", [ 23 ] including a revised Transceiver Facility in 2017, [ 24 ] an energy Management API in 2018, [ 25 ] and a Timing Service Facility [ 26 ] in 2020. The Forum also worked to establish Test and Certification Procedures for SCA 4.1. In 2015, the Committee rebranded as the “Software Defined Systems Committee” following the publication of the Committee’s Strategic Plan. [ 27 ] In 2023, the JTNC “transferred the Software Communications Architecture (SCA) v2.2.2 test procedures and JTNC Test Application (JTAP) to the Wireless Innovation Forum to share with the SCA development community.” [ 28 ] The Wireless Innovation Committee was originally formed in 2013 as the Spectrum Innovation Committee. [ 29 ] This Technology Committee was an evolution of the previous User Requirements Committee [ 30 ] acting “to advocate for the innovative utilization of spectrum, and advancing radio technologies that support essential or critical communications”. The Committee previously defined and published a "Top 10 Most Wanted Wireless Innovations" list, and also manages the Forum's Advocacy Agenda. The Committee was rebranded in 2015 to the Committee on Spectrum Innovation [ 31 ] and then again in 2016 as the Advanced Technologies Committee [ 32 ] to avoid name space confusion with the Spectrum Sharing Committee. The role of the committee had expanded at this point to include acting “as an incubator for exploring potential new markets relevant to the Forum’s mission”. The Committee rebranded again in 2022 to the Wireless Innovation Committee as a part of the Forum’s revised strategic plan. [ 33 ] The CBRS Committee spun out of the Spectrum Innovation Committee as the Spectrum Sharing Committee in 2015. [ 34 ] The purpose of this Commercialization Committee was to “serve as a common industry and government standards body to support the development and advancement of spectrum sharing technologies based on the three-tier architecture proposed for the 3.5 GHz (CBRS Band) rulemaking activities”. The result of their initial efforts was the development of the baseline standards necessary for the commercialization of the band. [ 35 ] [ circular reference ] In 2019, the Spectrum Sharing Committee began work on “Release 2 Standards” to add new features and capabilities to the baseline specifications, [ 36 ] and in 2023 they added “Release 1+ Standards” to address regulatory changes impacting the baseline specifications. [ 37 ] The details of Release 1+ and Release 2 are captured in the Committee’s “Release Plan”. [ 38 ] In 2023, the Committee rebranded to the CBRS Committee reflecting their actual activities and in alignment with the Forum’s new Strategic Plan. [ 39 ] The 6 GHz Committee spun out of the Advanced Technologies Committee in 2019 to serve “as an industry body to study and specify sharing arrangements in spectrum designated for unlicensed operation in the U-NII-5 and U-NII-7 bands. [ 40 ] [ 41 ] [ circular reference ] This Commercialization Committee partnered with the Wi-Fi Alliance to deliver the system standardization and testing required for AFC System Certification. [ 42 ] The WInnForum maintains a Regulatory Advisory Committee “made up of regulatory and public policy officials and experts from around the world who are working on or knowledgeable about issues relevant to advanced wireless and radio technologies”. [ 43 ] From 2014 to 2023, the WInnForum hosted an India Regional Committee supporting the needs of its member organizations based in India. In 2022, the marketing work groups from each of the four active committees were merged into a “Joint Marketing Group” chartered to help promote WInnForum work products and activities and to define and coordinate messaging for approval, as appropriate, by the various steering groups. The membership of the Wireless Innovation Forum consists of commercial, defense, and civil government organizations at all levels of the wireless value chain, including wireless service providers, network operators, component and equipment manufacturers, hardware and software developers, regulatory agencies, and academia. [ 44 ] The Forum presents three achievement awards. [ 45 ] Winners of the Wireless Innovation Forum Awards over the years can be found here: https://www.wirelessinnovation.org/sdr_achievement_awards Awards are also made each year to the authors of the top papers from the previous year's Technical Conference, as determined by an independent panel of judges.	https://en.wikipedia.org/wiki/Wireless_Innovation_Forum
Wireless Intelligent Network (also referred to as a WIN ) is a concept developed by the TR-45 Mobile and Personal Communications Systems Standards engineering committee of the Telecommunications Industry Association (TIA). Its objective is to transport the resources of the Intelligent Network to the wireless network, utilizing the TIA-41 set of technical standards. [ 1 ] [ 2 ] Basing WIN standards on this protocol allows changing to an intelligent network without making current network infrastructure obsolete. Today's wireless subscribers are much more sophisticated telecommunications users than they were five years ago. No longer satisfied with just completing a clear call, today's subscribers demand innovative ways to use the wireless phone. They want multiple services that allow them to handle or select incoming calls in a variety of ways. Enhanced services are very important to wireless customers. They have come to expect, for instance, services such as caller ID and voice messaging bundled in the package when they buy and activate a cellular or personal communications service (PCS) phone. Whether prepaid, voice/data messaging, Internet surfing, or location-sensitive billing, enhanced services will become an important differentiator in an already crowded, competitive service-provider market. Enhanced services will also entice potentially new subscribers to sign up for service and will drive up airtime through increased usage of PCS or cellular services. As the wireless market becomes increasingly competitive, rapid deployment of enhanced services becomes critical to a successful wireless strategy. Intelligent Network (IN) solutions have revolutionized wireline networks. Rapid creation and deployment of services has become the hallmark of a wireline network based on IN concepts. Wireless Intelligent Network (WIN) will bring those same successful strategies into the wireless networks. The evolution of wireless networks to a WIN concept of service deployment delivers the following advantages, similar to the IN benefits reaped by wireline providers: • Multivendor product offerings that faster competition • Uniform services to subscribers across service areas • Efficient network use • Service creation and deployment TIA-41 describes procedures necessary to provide certain services requiring interaction between different cellular systems to cellular radio telephone subscribers. The standards aim to address the ongoing and developing concerns of the cellular radiotelecommunications industry with regard to useful and effective services requiring standardized intersystem procedures. [ 3 ] This article about wireless technology is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_Intelligent_Network
A wireless LAN controller (WLC) is a network device used to monitor and manage wireless access points in an organization. WLCs are connected to routers and allow devices from across the organization to connect to the router via access points. WLCs are generally used in combination with the Lightweight Access Point Protocol (LWAPP) to manage light-weight access points in bulk by the network administrator or network operations center . [ 1 ] The wireless LAN controller is part of the Data Plane within the Cisco Wireless Model. The WLAN controller automatically handles the configuration of wireless access-points . It centralizes wireless network infrastructure and handles bandwidth allocation to the access points (APs). Before the use of WLCs were widespread, APs had to handle connections individually, leading to unstable data links and poor connections. The use of WLCs solves this problem. This computer networking article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_LAN_controller
Wireless Latin Entertainment ( WILAEN ) is a United States producer and distributor of Latin digital entertainment content formed in 2001. The WILAEN distribution network has a presence in eight countries: Argentina , Brazil , Colombia , Dominican Republic , Guatemala , Mexico , Peru , and the U.S . [ 1 ] Through its brand, Latin Garage, WILAEN produces and distributes digital services and content, such as mastertones , ringbacks, polyphonic ringtones , video ringers, images and wallpapers , and full-track downloads. [ 2 ] External Links: AT&T Wireless Offers Latin Mobile Content This article about an entertainment company in the United States is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_Latin_Entertainment
Wireless Multimedia Extensions ( WME ), also known as Wi-Fi Multimedia ( WMM ), is a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e standard. It provides basic Quality of service (QoS) features to IEEE 802.11 networks. WMM prioritizes traffic according to four Access Categories (AC): voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). However, it does not provide guaranteed throughput . It is suitable for well-defined applications that require QoS, such as Voice over IP (VoIP) on Wi-Fi phones ( VoWLAN ). WMM replaces the Wi-Fi DCF distributed coordination function for CSMA/CA wireless frame transmission with Enhanced Distributed Coordination Function (EDCF). EDCF, according to version 1.1 of the WMM specifications by the Wi-Fi Alliance, defines Access Categories labels AC_VO, AC_VI, AC_BE, and AC_BK for the Enhanced Distributed Channel Access (EDCA) parameters that are used by a WMM-enabled station to control how long it sets its Transmission Opportunity (TXOP), according to the information transmitted by the access point to the station. It is implemented for wireless QoS between RF media. The Wi-Fi Alliance has added Power Save Certification to the WMM specification. Power Save uses mechanisms from 802.11e and legacy 802.11 to save power (for battery powered equipment) and fine-tune power consumption. The certification provides an indication that the certified product is targeted for power critical applications like smart phones and portable power devices (i.e. those that require battery or recharging such as smart phones.) The underlying concept of WMM PowerSave is that the station (STA) triggers the release of buffered data from the access point (AP) by sending an uplink data frame . Upon receipt of such a data (trigger) frame the AP releases previously buffered data stored in each of its queues. Queues may be configured to be trigger-enabled, (i.e. a receipt of a data frame corresponding to the queue acts as trigger), and delivery enabled, (i.e. data stored at those queues will be released upon receipt of a frame). Queues refer to the four ACs defined for WMM.	https://en.wikipedia.org/wiki/Wireless_Multimedia_Extensions
The Wireless Network after Next (WNaN) was a DARPA project to create and demonstrate an advanced tactical mobile ad-hoc network (MANET) that rapidly adapts to soldiers maneuvering in complicated environments, automatically determining the best radio frequencies and network paths to maximize connectivity and throughput. In 2010 it was successfully demonstrated in live military experiments containing up to 100 nodes, the largest military MANET demonstrated to that date. The Wireless Network after Next consisted of a novel radio platform, created by Cobham plc , and novel networking protocols, created by BBN Technologies :	https://en.wikipedia.org/wiki/Wireless_Network_after_Next
The Wireless Router Application Platform ( WRAP ) is a format of single board computer defined by Swiss company PC Engines . This is specially designed for wireless router , firewall , load balancer , VPN or other network appliances. There are three different models of the WRAP: The WRAP is capable of running many different operating systems, including various Linux distributions , FreeBSD , NetBSD , OpenBSD , as well as proprietary OSes. The WRAP lacks a keyboard controller (for obvious reasons), so some OSes that rely on one for the boot process may have to be modified. PC Engines announced the end of life for the WRAP platform in 2007. The board was replaced by the ALIX. This computing article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_Router_Application_Platform
Wireless wide area network ( WWAN ), is a form of wireless network . The larger size of a wide area network compared to a local area network requires differences in technology. Wireless networks of different sizes deliver data in the form of telephone calls, web pages, and video streaming. A WWAN often differs from wireless local area network (WLAN) by using mobile telecommunication cellular network technologies such as 2G , 3G , 4G LTE , and 5G to transfer data. It is sometimes referred as Mobile Broadband . These technologies are offered regionally, nationwide, or even globally and are provided by a wireless service provider . WWAN connectivity allows a user with a laptop and a WWAN card to surf the web, check email, or connect to a virtual private network (VPN) from anywhere within the regional boundaries of cellular service. Various computers can have integrated WWAN capabilities. A WWAN may also be a closed network that covers a large geographic area. For example, a mesh network or MANET with nodes on buildings, towers, trucks, and planes could also be considered a WWAN. A WWAN may also be a low-power, low-bit-rate wireless WAN, ( LPWAN ), intended to carry small packets of information between things , often in the form of battery operated sensors. Since radio communications systems do not provide a physically secure connection path, WWANs typically incorporate encryption and authentication methods to make them more secure. Some of the early GSM encryption techniques were flawed, and security experts have issued warnings that cellular communication, including WWAN, is no longer secure. [ 1 ] UMTS (3G) encryption was developed later and has yet to be broken. [ citation needed ]	https://en.wikipedia.org/wiki/Wireless_WAN
The Wireless Washtenaw project was originally an ambitious plan to provide free wireless broadband access throughout Washtenaw County, Michigan , by April 2008 "without a burden on taxpayers". To accomplish this, it was to rely upon a public/ private sector partnership between the Washtenaw County government and 20/20 Communications. In March 2010, due to a failure to qualify for a certain anticipated federal stimulus grant, 20/20 Communications sold most of its operations to 123Net . [ 1 ] 20/20 Communications however continues to be 123.net's sales representative for the Washtenaw County area via its website and sales office. [ 2 ] 123.net has continued to maintain the Wireless Washtenaw network, and in the downtown Ann Arbor area has significantly expanded its transmission capabilities to include the 4G WiMAX microwave band. Their 4G WiMAX service is a business class product offered outside of the original Wireless Washtenaw project. It has also upgraded some of the network equipment of the project as well. [ 2 ] As of November 2010, the network provided wireless internet access options to downtown Ann Arbor , Manchester , Saline , Chelsea , and Dexter . [ 3 ] From 2008 through 2010 it became increasingly clear that all of the original goals of the Wireless Washtenaw program were not being achieved by the deadlines as originally stipulated in the 20/20 Communications contract. Since acquisition by 123.net, unless and until an additional source of significant funding for the program might be found, 20/20 Communications, under 123.net has restated the more realistic goals of the plan as merely hoping, "to revisit the possibility of slowly expanding the Wireless Washtenaw network sometime next summer (2011)." [ 2 ] One estimate for the amount of additional funding needed to provide full coverage to the county is $10,000,000. [ 1 ] New 'free' subscriptions to the service are no longer offered on the 20/20 website. 20/20 also no longer advertises any pricing on its website (November 2010). [ 4 ] Washtenaw County, Michigan, has described the goals of Wireless Washtenaw to be the following; 2004 2005 2006 2007 (The original contract with 20/20 Communications called for completion of countywide deployment by April 2008. 20/20 has explained the shortfall as being due to the nationwide economic slowdown of 2007, which caused a lack of anticipated funding sources.) [ 5 ] In March 2007, 20/20 Communications completed the Wireless Washtenaw Pilot Phase. As of November, 2010, due to lack of funding, 123.net and 20/20 remain in the Pre-Deployment phase of setting up Wireless Washtenaw. Ann Arbor As of 11/17/2006, radios have been installed on street lamps or traffic signal arms on: Each radio transmits 300 to 600 feet depending on obstructions. These radios transmit the 802.11b and g WiFi signal in the 2.4 GHz range. Manchester Radios were installed on the Manchester water tower in November 2006. They broadcast the pre-wimax 802.11a signal on the 5.7 GHz band in a 1.5-mile radius. Manchester area residents need to install a radio on their homes as well to receive and translate the signal. Saline There are two separate types of signals in the Saline pilot. For home users, Radios have been installed on the Henry Street water tower. They broadcast in the 802.11a Pre-wimax WiFi signal covering an area 360 degrees for 1.5 miles. Residents need a radio mounted on their home to receive this signal. The downtown business Saline area on US-12 also receives the 802.11b and G WiFi signal on the 2.4 GHz band. Chelsea and Dexter As of November 2010, the 20/20 website advertises its coverage as also including the towns of Dexter and Chelsea. Washtenaw County, Michigan, issued a Request for Information on June 7, 2005; by the June 29, 2005, deadline set fourth by the county, 23 private sector corporations responded to the RFI were received. These companies include: After reviewing the results of the Wireless Washtenaw RFI, the county release a Request For Proposal on November 29, 2005. On June 15, 2006, the Wireless Washtenaw Advisory Board recommended to the county that 20/20 Communications be selected as the private sector partner for Wireless Washtenaw. The recommendation was given final approval on August 2, 2006. In early 2010, 20/20 Communications sold its ownership share of Wireless Washtenaw to 123.net. [ 6 ]	https://en.wikipedia.org/wiki/Wireless_Washtenaw
Wireless Zero Configuration ( WZC ), also known as Wireless Auto Configuration , or WLAN AutoConfig , is a wireless connection management utility included with Microsoft Windows XP and later operating systems as a service that dynamically selects a wireless network to connect to based on a user's preferences and various default settings. [ 1 ] [ 2 ] This can be used instead of, or in the absence of, a wireless network utility from the manufacturer of a computer's wireless networking device. The drivers for the wireless adapter query the NDIS Object IDs and pass the available network names ( SSIDs ) to the service. The service then lists them in the user interface on the Wireless Networks tab in the connection's Properties or in the Wireless Network Connection dialog box accessible from the notification area. A checked (debug) [ 3 ] build version of the WZC service can be used by developers to obtain additional diagnostic and tracing information logged by the service. Wireless Zero Configuration was first introduced with Windows XP . In Windows Vista and Windows 7 , the service that provides equivalent functionality is called "WLAN AutoConfig". It is based on the Native Wi-Fi architecture introduced in Windows Vista. Initially, there was no Wireless LAN API in Windows XP for developers to create wireless client programs and manage profiles and connections. After the release of Windows Vista, Microsoft released KB918997, [ 4 ] which includes a Wireless LAN API for Windows XP SP2. It was later integrated into Windows XP Service Pack 3.	https://en.wikipedia.org/wiki/Wireless_Zero_Configuration
A wireless application service provider ( WASP ) is the generic name for a firm that provides remote services, typically to handheld devices, such as cellphones or PDAs, that connect to wireless data networks. WASPs are a specific category of application service providers (ASPs), though the latter term may more often be associated with standard web services. They can also be used for wireless bridging between different types of network topologies . This article about wireless technology is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_application_service_provider
Wireless broadband is a telecommunications technology that provides high-speed wireless Internet access or computer networking access over a wide area. The term encompasses both fixed and mobile broadband . [ 1 ] Originally the word " broadband " had a technical meaning, but became a marketing term for any kind of relatively high-speed computer network or Internet access technology. According to the 802.16-2004 standard, broadband means "having instantaneous bandwidths greater than 1 MHz and supporting data rates greater than about 1.5 Mbit /s." [ 2 ] The Federal Communications Commission (FCC) recently re-defined the word to mean download speeds of at least 25 Mbit /s and upload speeds of at least 3 Mbit /s. [ 3 ] A wireless broadband network is an outdoor fixed and/or mobile wireless network providing point-to-multipoint or point-to-point terrestrial wireless links for broadband services. Wireless networks can feature data rates exceeding 1 Gbit/s. [ 4 ] Many fixed wireless networks are exclusively half-duplex (HDX) , however, some licensed and unlicensed systems can also operate at full-duplex (FDX) [ 5 ] allowing communication in both directions simultaneously. Outdoor fixed wireless broadband networks commonly use a priority TDMA based protocol [ 6 ] [ 7 ] [ 8 ] [ 9 ] in order to divide communication into timeslots. This timeslot technique eliminates many of the issues common to 802.11 Wi-Fi protocol in outdoor networks such as the hidden node problem . Few wireless Internet service providers (WISPs) provide download speeds of over 100 Mbit/s; most broadband wireless access (BWA) services are estimated to have a range of 50 km (31 mi) from a tower. [ 10 ] Technologies used include Local Multipoint Distribution Service (LMDS) and Multichannel Multipoint Distribution Service (MMDS), as well as heavy use of the industrial, scientific and medical (ISM) radio bands and one particular access technology was standardized by IEEE 802.16 , with products known as WiMAX . [ 11 ] WiMAX is highly popular in Europe but has not been fully accepted in the United States because cost of deployment. In 2005 the Federal Communications Commission adopted a Report and Order that revised the FCC's rules to open the 3650 MHz band for terrestrial wireless broadband operations. [ 11 ] Another system that is popular with cable internet service providers uses point-to-multipoint wireless links that extend the existing wired network using a transparent radio connection. This allows the same DOCSIS modems to be used for both wired and wireless customers. [ 12 ] On November 14, 2007, the Commission released Public Notice DA 07–4605 in which the Wireless Telecommunications Bureau announced the start date for licensing and registration process for the 3650–3700 MHz band. [ 13 ] In 2010 the FCC adopted the TV White Space Rules (TVWS) and allowed some of the better no line of sight frequency (700 MHz) into the FCC Part-15 Rules. [ 14 ] The Wireless Internet Service Providers Association, a national association of WISPs, petitioned the FCC and won. [ 15 ] Initially, WISPs were found only in rural areas not covered by cable or DSL . [ 16 ] These early WISPs would employ a high-capacity T-carrier , such as a T1 or DS3 connection, and then broadcast the signal from a high elevation, such as at the top of a water tower . To receive this type of Internet connection, consumers mount a small dish to the roof of their home or office and point it to the transmitter. Line of sight is usually necessary for WISPs operating in the 2.4 and 5 GHz bands with 900 MHz offering better NLOS (non-line-of-sight) performance. Providers of fixed wireless broadband services typically provide equipment to customers and install a small antenna or dish somewhere on the roof. This equipment is usually deployed as a service and maintained by the company providing that service. Fixed wireless services have become particularly popular in many rural areas where cable, DSL or other typical home internet services are not available. Many companies in the US and worldwide have started using wireless alternatives to incumbent and local providers for internet and voice service. These providers tend to offer competitive services and options in areas where there is a difficulty getting affordable Ethernet connections from terrestrial providers such as ATT, Comcast, Verizon and others. Also, companies looking for full diversity between carriers for critical uptime requirements may seek wireless alternatives to local options. To cope with increased demand for wireless broadband, increased spectrum would be needed. Studies began in 2009, and while some unused spectrum was available, it appeared broadcasters would have to give up at least some spectrum. This led to strong objections from the broadcasting community. In 2013, auctions were planned, and for now any action by broadcasters is voluntary. In the United States, mobile broadband technologies include services from providers such as Verizon , AT&T Mobility , and T-Mobile which allow a more mobile version of Internet access. Consumers can purchase a PC card , laptop card, USB equipment, or mobile broadband modem , to connect their PC or laptop to the Internet via cell phone towers . [ 17 ] [ 18 ] [ 19 ] [ 20 ] [ 21 ] [ 22 ] [ 23 ] [ 24 ] This type of connection would be stable in almost any area that could also receive a strong cell phone connection. These connections can cost more for portable convenience as well as having speed limitations in all but urban environments. [ 19 ] [ 1 ] [ 25 ] [ 26 ] [ 27 ] On June 2, 2010, after months of discussion, AT&T became the first wireless Internet provider in the US to announce plans to charge according to usage. As the only iPhone service in the United States, AT&T experienced the problem of heavy Internet use more than other providers. About 3 percent of AT&T smart phone customers account for 40 percent of the technology's use. 98 percent of the company's customers use less than 2 gigabytes (4000 page views, 10,000 emails or 200 minutes of streaming video ), the limit under the $25 monthly plan, and 65 percent use less than 200 megabytes , the limit for the $15 plan. For each gigabyte in excess of the limit, customers would be charged $10 a month starting June 7, 2010, though existing customers would not be required to change from the $30 a month unlimited service plan. The new plan would become a requirement for those upgrading to the new iPhone technology later in the summer. [ 28 ] A wireless connection can be either licensed or unlicensed. In the US, licensed connections use a private spectrum the user has secured rights to from the Federal Communications Commission (FCC). The unlicensed mobile wireless broadband, in US operates on CBRS [ 29 ] Which has three tiers. Tier 1 – Incumbent Access, reserved for US Federals Government, Tier 2 – Priority Access, a paid access with priority on the spectrum, Tier 3 – General Authorized Access (GAA), a shared spectrum. [ 29 ] In other countries, spectrum is licensed from the country's national radio communications authority (such as the ACMA in Australia or Nigerian Communications Commission in Nigeria (NCC)). Licensing is usually expensive and often reserved for large companies who wish to guarantee private access to spectrum for use in point to point communication. Because of this, most wireless ISP's use unlicensed spectrum which is publicly shared. [ 30 ] ==References==	https://en.wikipedia.org/wiki/Wireless_broadband
A wireless configuration utility , [ 1 ] wireless configuration tool , [ 1 ] wireless LAN client , [ citation needed ] or wireless connection management utility [ citation needed ] is a class of network management software that manages the activities and features of a wireless network connection. [ 2 ] [ 3 ] [ 4 ] It may control the process of selecting an available access point , authenticating and associating to it and setting up other parameters of the wireless connection. [ 5 ] There are many wireless LAN clients available for use. Clients vary in technical aspects, support of protocols and other factors. Some clients only work with certain hardware devices, while others only on certain operating systems. The table below compares various wireless LAN clients.	https://en.wikipedia.org/wiki/Wireless_configuration_utility
A wireless distribution system ( WDS ) is a system enabling the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points without the traditional requirement for a wired backbone to link them. The notable advantage of WDS over other solutions is that it preserves the MAC addresses of client frames across links between access points. [ 1 ] An access point can be either a main, relay, or remote base station . All base stations in a wireless distribution system must be configured to use the same radio channel, method of encryption (none, WEP , WPA or WPA2) and the same encryption keys. They may be configured to different service set identifiers (SSIDs) . WDS also requires every base station to be configured to forward to others in the system. WDS may also be considered a repeater mode because it appears to bridge and accept wireless clients at the same time (unlike traditional bridging ). However, with the repeater method, throughput is halved for all clients connected wirelessly. This is because Wi-Fi is an inherently half duplex medium and therefore any Wi-Fi device functioning as a repeater must use the Store and forward method of communication. WDS may be incompatible between different products (even occasionally from the same vendor) since the IEEE 802.11-1999 standard does not define how to construct any such implementations or how stations interact to arrange for exchanging frames of this format. The IEEE 802.11-1999 standard merely defines the 4-address frame format that makes it possible. [ 2 ] WDS may provide two modes of access point-to-access point (AP-to-AP) connectivity: Two disadvantages to using WDS are: OpenWRT , a universal third party router firmware, supports WDS with WPA-PSK, WPA2-PSK, WPA-PSK/WPA2-PSK Mixed-Mode encryption modes. Recent Apple base stations allow WDS with WPA, though in some cases firmware updates are required. Firmware for the Renasis SAP36g super access point and most third party firmware for the Linksys WRT54G(S)/GL support AES encryption using WPA2-PSK mixed-mode security, and TKIP encryption using WPA-PSK, while operating in WDS mode. However, this mode may not be compatible with other units running stock or alternate firmware. Suppose one has a Wi-Fi-capable game console . This device needs to send one packet to a WAN host, and receive one packet in reply. Notice that network 1 (non-WDS) and network 3 (WDS) send the same number of packets over-the-air. The only slowdown is the potential halving due to the half-duplex nature of Wi-Fi. [ 3 ] Network 2 gets an additional halving because the remote base station uses double the air time because it is re-transmitting over-the-air packets that it has just received over-the-air. This is the halving that is usually attributed to WDS, but that halving only happens when the route through a base station uses over-the-air links on both sides of it. That does not always happen in a WDS, and can happen in non-WDS. Important Note: This "double hop" (one wireless hop from the main station to the remote station, and a second hop from the remote station to the wireless client [game console]) is not necessarily twice as slow. End to end latency introduced here is in the "store and forward" delay associated with the remote station forwarding packets. In order to accurately identify the true latency contribution of relaying through a wireless remote station vs. simply increasing the broadcast power of the main station, more comprehensive tests specific to the environment would be required.	https://en.wikipedia.org/wiki/Wireless_distribution_system
Wireless Engineering is the branch of engineering which addresses the design, application, and research of wireless communication systems and technologies. Wireless engineering is an engineering subject dealing with engineering problems using wireless technology such as radio communications and radar, but it is more general than the conventional radio engineering. It may include using other techniques such as acoustic, infrared, and optical technologies. Wireless technologies have skyrocketed since their late 19th Century advancements. With the invention of the FM radio in 1935, wireless communications have become a concentrated focus of both private and government sectors. Auburn University 's Samuel Ginn College of Engineering was the first in the United States to offer a formalized undergraduate degree in such a field. The program was initiated by Samuel Ginn, an Auburn Alumni, in 2001. [ 1 ] [ 2 ] Auburn University's college of engineering divides their wireless engineering program into two areas of applicable study: electrical engineering (pertaining to circuit design, digital signal processing , antenna design , etc.), and software-oriented wireless engineering (communications networks, mobile platform applications, systems software, etc.) [ 3 ] Macquarie University in Sydney , was the first University to offer Wireless Engineering in Australia . The university works closely with nearby industries in research and teaching development in wireless engineering. [ 4 ] Universiti Teknikal Malaysia Melaka in Malacca , was the first University to offer Wireless Communication Engineering in Malaysia . Wireless engineering contains a wide spectrum of application, most notably cellular networks . The recent popularity of cellular networks has created a vast career demand with a large repository. The popularity has also sparked many wireless innovations, such as increased network capacity, 3G , cryptology and network security technologies.	https://en.wikipedia.org/wiki/Wireless_engineering
A Wireless game adapter is a device that, once connected to a video game console or handheld , enables internet and\or multiplayer access. The Wireless Network Adapter for the Xbox 360 is a device that is plugged into the system's rear USB port, allowing for access to the internet via a wireless router. While the Wii has built-in wireless capabilities, it is not compatible with every wireless router. For this reason Nintendo released the Nintendo Wi-Fi USB Connector peripheral that a Wii can connect wirelessly to via an internet enabled computer, wireless or otherwise. The Mobile Adapter GB , was a short-lived peripheral that allowed the handheld Game Boy Color and Game Boy Advance consoles to connect to a mobile phone , utilizing its cellular network for online interactions via the Mobile System GB service. Following delays, the device and service launched in Japan on 27 January 2001. Together, they enabled online functionality for roughly 20 games, most notably Pokémon Crystal and Mobile Golf . Nintendo ultimately chose not to release the adapter outside Japan, citing international wireless incompatibilities and market differences. Its high costs and limited game compatibility hindered widespread adoption, with only 80,000 units sold in its first year. The Mobile System GB service was discontinued on 18 December 2002. The Game Boy Advance and its two redesigns, the Game Boy Advance SP and the Game Boy Micro all had wireless adapters that were meant to replace the link cable used for local multiplayer. It is not compatible with any game released prior to the adapter's release, and afterwards was only compatible with a select few games . [ 1 ] Much like the Wii, the Nintendo DS has built-in wireless capabilities and is similarly not compatible with all wireless routers. Another hindrance is that the DS does not support certain levels of wi-fi encryption (e.g. WPA ), thus necessitating the Nintendo Wi-Fi USB Connector.	https://en.wikipedia.org/wiki/Wireless_game_adapter
Wireless grids are wireless computer networks consisting of different types of electronic devices with the ability to share their resources with any other device in the network in an ad hoc manner. A definition of the wireless grid can be given as: "Ad hoc, distributed resource-sharing networks between heterogeneous wireless devices" The following key characteristics further clarify this concept: The technologies that make up the wireless grid can be divided into two main categories; ad hoc networking and grid computing . In traditional networks, both wired and wireless, the connected devices, or nodes, depend on dedicated devices ( edge devices ) such as routers and/or servers for facilitating the throughput of information from one node to the other. These 'routing nodes' have the ability to determine where information is coming from and where it is supposed to go. They give out names and addresses ( IP addresses ) to each connected node and regulate the traffic between them. In wireless grids, such dedicated routing devices are not (always) available and the bandwidth that is permanently available to traditional networks has to be either 'borrowed' from an already existing network or publicly accessible bandwidth ( open spectrum ) has to be used. A group addressing this problem is MANET (Mobile Ad Hoc Network). One of the intended aspects of wireless grids is that it will facilitate the sharing of a wide variety of resources. These will include both technical as information resources. The former being bandwidth, QoS , and web services , but also computational power and data storage capacity. Information resources can include virtually any kind of data from databases and membership lists to pictures and directories. Ad hoc resource sharing between mobile devices in the wireless grid require for the devices to agree on sharing/communication protocols without the existence of dedicated servers. Coordination Systems are the actual mechanisms that enable the sharing of resources between different devices. For different resources, devices use different coordination systems. Examples of such mechanisms are: SMB or NFS for sharing disk space and the distributed.net client for sharing processor cycles. Before users are willing to share any resource, they demand a certain amount of trust between them and the users and/or systems they share resources with. The amount of trust required depends on the kind of information/resource that is to be shared. Sharing processor cycles requires less substantial trust then the sharing of personal information and commercial information can require another level of trust establishment altogether. There are systems currently in operation that can provide a certain amount of trust like the public key infrastructure that makes use of certificates ; now often used in web based email systems, and Kerberos . Before any resource on a device in the grid can be utilized, those resources that are available must be discovered; all the devices that make up the grid and the resources they possess have to be identified. When a client enters the grid, such as a PDA , it has to be able to communicate to the other users that it is a PDA and it has a camera, GPS capabilities, a telephone function and various office applications such as a text editor . Protocols like UPnP and zeroconf can detect a new node in the network when it enters. When detected, other users can send a query to the new device to find out what it has to offer. Commercial service providers can 'advertise' the resources they have to offer through IP multicasts . Within large grids containing thousands of nodes, a kind of 'friend of a friend' mechanism can be used. There is a myriad of standards that include resource description protocols. Standards as IETF 's zeroconf, Microsoft's UPnP , the Grid Resource Description Language (GRDL), the Web Services Description Language (WSDL) for describing various specific web services and parts of QoS that describe bandwidths all offer devices a way to describe and publish their specific resources and needs. There are also various systems currently available that can gather these resource descriptions and structure them for other devices to use. The OpenGrid Services Architecture ( OGSA ) uses a Web service-style IndexService. The Web services community has defined UDDI which can makes a database of services that are available on the network, and JXTA uses zeroconf to identify resources in a network. However, the problem with using these in wireless grids is that no stable publisher of these descriptions may exist. For any device to be able to use any resource, a way to identify and describe the resource has to be agreed on by all available devices. If, for instance, storage capacity is to be shared, it first has to be clear what the capacity of each device is and what the storage need is. As said, there are many techniques to describe certain resources but there is not one technique that is able to provide this service for all resources. The available techniques combined, however, cover most of what is needed. Grid computing came into existence as a manner of sharing heavy computational loads among multiple computers to be able to compute highly complex mathematical problems (a good real-world example being the SETI@Home project). However, it developed rapidly into a way of sharing virtually any resource that is available on any machine on the grid. Wired grids are now used to share not only computing power, but also hard disk space, data, and applications. The grid topology is highly flexible and easily scalable, allowing users to join and leave the grid without the hassle of time and resource hungry identification procedures, having to adjust their devices or install additional software on them. The goal of grid computing is described as "to provide flexible, secure and coordinated resource sharing among dynamic collections of individuals, institutions and resources" (McKnight, Howison, 2004). It is intended to be a dynamic network without geographical, political, or cultural boundaries that offers real-time access to heterogeneous resources and still offer the same characteristics of the traditional distributed networks that are in use everywhere in our houses and offices. These characteristics being stability, scalability, and flexibility as the most important ones. Ian Foster offers a checklist for recognizing a grid. One of the biggest limitations of the wired grid is that users are forced to be in a fixed location as the devices they use are to be hard wired to the grid at all times. This also has a negative influence on the flexibility and scalability of the grid; devices can only join the grid in locations where the possibility exists to physically connect the device to the grid (i.e. there is the need for a hub or a switch to plug into). One description of the wireless grid is "an augmentation of a wired grid that facilitates the exchange of information and the interaction between heterogeneous wireless devices" (Argawal, Norman & Gupta, 2004) Argawal, Norman & Gupta (2004) identify three forces that drive the development of the wireless grid: New user interaction modalities and form factors Applications that exist on current wired grids need to be adapted to fit the devices used in wireless grids. These devices are usually hand held and therefore the user interface devices (screens, keyboards (if any)) are significantly smaller and availability of additional input devices like a mouse are limited. This means the traditional graphical interfaces found on PCs are not suitable. Limited computing resources Wireless devices do not possess the computing power nor the storage capacity of full size devices like a PC or laptop. Therefore, wireless applications need to have access to additional computing resources to be able to offer the same functionality that wired networks do. Additional new supporting infrastructure elements In the case of an unforeseen event, there will be the need for major amounts of computational and communications bandwidths. An urban catastrophe, for example, would require a dynamic and adaptive wireless network to alert people within the population as well as those in the various coordination and aid services like the police, army, medical services, and government. Applications to provide for these bandwidths and 'instant' networks need to be addressed. The infrastructure of the wireless grid consists of three basic levels:	https://en.wikipedia.org/wiki/Wireless_grid
Wireless intelligent stream handling (WISH) is a type of software which prioritizes the traffic of different applications over a wireless network . WISH makes use of three different priority classifiers which enables a user to choose what kind of traffic should be preferred. [ 1 ] With this option enabled video and audio streams that use HTTP (so basically all videos played in the browser) are preferred over other kinds of traffic. With this option enabled the access point will recognize specific video and audio streams used by Media center PC's and Windows Media Center Extenders , for instance the Xbox 360 . Automatic mode makes the access point attempt to prioritize traffic that is recognized as a stream but not necessarily a HTTP or Windows Media Center stream. Also this de-prioritizes transfers such as file transfers. Since games and VoIP are left at normal priority so games and VoIP traffic have an advantage to. Also, WISH allows the user to configure the system based on the following things: This enables the user to set a certain computer to a lower priority. This could help if the PC is, for example, only used for downloading. Also, PCs that are used for downloading and streaming media can use this to prioritize the streaming media above downloading, therefore decreasing the time used to load the stream.	https://en.wikipedia.org/wiki/Wireless_intelligent_stream_handling
Wireless lock is a protection concept for authenticated LAN or WLAN network clients offered from various vendors in various functional shapes and physical designs. In contrast to wireless keys , wireless lock puts emphasis on automatic locking instead of just locking by time-out or unlocking. The wireless lock concept supports initialising the client with authentication and log-on as electronic key solutions. Beyond that a wireless lock supports automatic log-off after user leaves unlocked network client and independent from time-out conditions. Protection comes into effect, while integrated or galvanically attached and paired receiver/transceiver stays connected with protected client object as soon as wireless token gets separated from client exceeding a set maximum allowed distance, generally the manual reach required for operating keyboard attached to client. Currently (2011-07) there is no general standard supporting inter-operability of wireless lock concepts. The wireless token serves as an independent second authentication factor. Local pairing of token with protected networked client object is the authentication procedure. Personalisation of token with user is a preparative action that may be administered apart from network. Allocated user credentials shall be served from networked authorisation server for allowed access to data and function and from authentication server for allowed access to network and clients. A wireless communication distance metrics sets the protected object to "locked", as soon as the set distance level between paired transmitter and receiver of a wireless signal transmission is exceeded. The protected object returns to status "unlocked" as soon as the distance gets lesser and the received signal strength level higher than set limit. Transmitters may be worn by the owner of an object, whereas the other receiver item gets attached to the protected object for logically protecting it to usage by the owner only. Basic electronic gadget is a wireless token that communicates with a counterpart attached to the object to be controlled wirelessly. User guides for mode of operation recommend to bear a very light designed alarm token with a necklace, a wristband or similarly directly bound to the body. Very low transmission power levels secure low electromagnetic interference as well as entirely biologically harmless operation After setting the object to protect to work and initially pairing the two wireless token devices with each other, the protected object refuses operation when exceeding the set distance between token and protected object. Advanced solutions offer communications on the basis of standardized communication protocols and based on standardized air interface links. Simple solutions make use of passive RFID tokens, thus requiring a higher transmission level from a reader attached to the protected object and illuminating the token for response. Chosen frequency band and allowed maximum transmission power level define the possible reach for the response from the token in the vicinity of the protected object. Application is mainly known PC locking under for authenticated log-in conditions. Protected object controlling works with the token at hands working as a transceiver (RFID passive) or beacon transmitter (RFID active. Currently some similar applications are offered by several no-name vendors and under non-guaranteed specification. Relevant existing standard for such application is Bluetooth V4.0 Low Energy of 2009-12-17 with the profiles Find Me and Proximity . [ 2 ] Published concepts for secure key transmission are published in several context. [ 3 ] Standardisation in IETF ( PKI ), W3C ( XML ), ITU ( X.509 ) is going on. Basically there are different concepts available for implementing a sound security concept: The metrics options for detecting separation of protected object and authenticated user have to take into account various physical phenomena and thus offer a variety of signal processing to overcome The safe approach is travel time estimation with ultra-short pulses (e.g. UWB and CSS ), the cheap approach is RSSI estimate with just variation of power levels. [ citation needed ] Many current product offers with reference to communication standards are just prototypes. Basic design is proposed e.g. with Texas Instruments sample offer using Bluetooth V4.0 low energy protocol standard [ 4 ] and with comparable proposals of other chip foundries. Currently (2011-07) there is no certified product according to ISO/IEC 15408 security requirements on offer. However any workable solution is better than nothing compared to logged-in work positions left unobserved. [ citation needed ] Well known implementation is Linux and Windows available BlueProximity [ 5 ] solution. The hosting on PC like systems allows for detecting presence of mobile phones in proximity to PC-attached Bluetooth dongle or equivalent interface. PC gets locked on leave. Reported and other simple deficiencies of this solution are: However this Bluetooth based approach is the best protected solution compared to other proprietary approaches without means comparable to mobile phone SIM locking or to Bluetooth link protection. Basic infrastructure requirements with wireless locking are very low. There are no additional server function requirements beyond public key infrastructure standards. The infrastructure requirement to include wireless receiver to protected objects via integration or using dongles is state-of-the-art. All tampering may be detected automatically. Attachment of receiver/transmitter in dongle shaping to protected object is easily made via USB port. Small security application will make use of protection mechanisms of operating system of protected object. Neither dongle nor protected unit may be compromised as long as any tampering of security application gets detected. Major advantage with wireless locking comes with automating log-off. Hence common lacking of caution by mobile users may be entirely compensated. Automatic wireless authentication factors do not require any handling. The only requirement to the user just to wear a token without any keying is unsurpassed in comfort and functional value. Wireless locking provides additional security for networks against fraudulent access and usage. Reported security deficits with second factor authentication may be compensated by reducing all burdens with keeping, handling and wearing such factors. [ 6 ] Transmission power of the wireless token for the object may be very low in the 1 mW range, as just the distance between the bearer and the item to be protected shall be bridged. That is a level causing no harm in any environment nor electromagnetic interference to sensitive may occur, i.e. interference with medical devices may be neglected. Wireless locking offers best robustness against de-authentication attacks . Continuous connection based encrypted key exchange between active token and receiver dongle provides a sufficient security level prepared for certification under ISO/IEC 15408 common criteria specification. Initially connection based encrypted key exchange serves for a lower security level which appears sufficient for most requirements. All known approaches for wireless locking are either proprietary [ 7 ] or just industrial standard, as e.g. ZigBee, ANT or other communication platforms, hence requiring special pairing of token and receiver/transmitter resp. Adherence to wireless air interface standards and wireless communications protocols compensates for such top level standardisation gap. Unidirectional communication between beaconing token and receiver dongle may be hacked with Man-in-the-middle attack . [ 8 ] However, connection based challenge–response initialisation serves a much higher security level. Clear specification of battery wear is not published with all known vendors' offerings.	https://en.wikipedia.org/wiki/Wireless_lock
Wireless mobility management in Personal Communications Service (PCS) is the assigning and controlling of wireless links for terminal network connections. Wireless mobility management provides an "alerting" function for call completion to a wireless terminal , monitors wireless link performance to determine when an automatic link transfer is required, and coordinates link transfers between wireless access interfaces. [ 1 ] One use of this is wireless push technology , by pushing data across wireless networks, this coordinates the link transfers and pushes data between the backend and wireless device only when an established connection is found. This article incorporates public domain material from Federal Standard 1037C . General Services Administration . Archived from the original on 2022-01-22. This article about wireless technology is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_mobility_management
A wireless network is a computer network that uses wireless data connections between network nodes . [ 1 ] Wireless networking allows homes, telecommunications networks , and business installations to avoid the costly process of introducing cables into a building, or as a connection between various equipment locations. [ 2 ] Admin telecommunications networks are generally implemented and administered using radio communication . This implementation takes place at the physical level (layer) of the OSI model network structure. [ 3 ] Examples of wireless networks include cell phone networks , wireless local area networks (WLANs) , wireless sensor networks, satellite communication networks, and terrestrial microwave networks. [ 4 ] The first professional wireless network was developed under the brand ALOHAnet in 1969 at the University of Hawaii and became operational in June 1971. The first commercial wireless network was the WaveLAN product family, developed by NCR in 1986. Advances in MOSFET (MOS transistor) wireless technology enabled the development of digital wireless networks . The wide adoption of RF CMOS ( radio frequency CMOS ), power MOSFET and LDMOS (lateral diffused MOS) devices led to the development and proliferation of digital wireless networks by the 1990s, with further advances in MOSFET technology leading to increasing bandwidth in the 2000s ( Edholm's law ). [ 5 ] [ 6 ] [ 7 ] Most of the essential elements of wireless networks are built from MOSFETs, including the mobile transceivers , base station modules, routers , RF power amplifiers , [ 6 ] telecommunication circuits , [ 8 ] RF circuits , and radio transceivers , [ 7 ] in networks such as 2G , 3G , [ 5 ] and 4G . [ 6 ] Wireless personal area networks (WPANs) connect devices within a relatively small area, that is generally within a person's reach. For example, both Bluetooth radio and invisible infrared light provides a WPAN for interconnecting a headset to a laptop. Zigbee also supports WPAN applications. [ 9 ] Wi-Fi PANs are becoming commonplace (2010) as equipment designers start to integrate Wi-Fi into a variety of consumer electronic devices. Intel "My WiFi" and Windows 7 "virtual Wi-Fi" capabilities have made Wi-Fi PANs simpler and easier to set up and configure. [ 10 ] A wireless local area network (WLAN) links two or more devices over a short distance using a wireless distribution method, usually providing a connection through an access point for internet access. The use of spread-spectrum or OFDM technologies may allow users to move around within a local coverage area, and still remain connected to the network. Products using the IEEE 802.11 WLAN standards are marketed under the Wi-Fi brand name. Fixed wireless technology implements point-to-point links between computers or networks at two distant locations, often using dedicated microwave or modulated laser light beams over line of sight paths. It is often used in cities to connect networks in two or more buildings without installing a wired link. To connect to Wi-Fi using a mobile device, one can use a device like a wireless router or the private hotspot capability of another mobile device. A wireless ad hoc network, also known as a wireless mesh network or mobile ad hoc network (MANET), is a wireless network made up of radio nodes organized in a mesh topology. Each node forwards messages on behalf of the other nodes and each node performs routing. [ 11 ] Ad hoc networks can "self-heal", automatically re-routing around a node that has lost power. Various network layer protocols are needed to realize ad hoc mobile networks, such as Distance Sequenced Distance Vector routing, Associativity-Based Routing , Ad hoc on-demand distance-vector routing , and Dynamic Source Routing . Wireless metropolitan area networks are a type of wireless network that connects several wireless LANs. Wireless wide area networks are wireless networks that typically cover large areas, such as between neighboring towns and cities, or city and suburb. These networks can be used to connect branch offices of business or as a public Internet access system. The wireless connections between access points are usually point to point microwave links using parabolic dishes on the 2.4 GHz and 5.8 GHz band, rather than omnidirectional antennas used with smaller networks. A typical system contains base station gateways, access points and wireless bridging relays. Other configurations are mesh systems where each access point acts as a relay also. When combined with renewable energy systems such as photovoltaic solar panels or wind systems they can be stand-alone systems. A cellular network or mobile network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver , known as a cell site or base station . In a cellular network, each cell characteristically uses a different set of radio frequencies from all their immediate neighbouring cells to avoid any interference. When joined these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones, pagers , etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission. Although originally intended for cell phones, with the development of smartphones , cellular telephone networks routinely carry data in addition to telephone conversations: Private LTE/5G networks use licensed, shared or unlicensed wireless spectrum thanks to LTE or 5G cellular network base stations, small cells and other radio access network (RAN) infrastructure to transmit voice and data to edge devices (smartphones, embedded modules, routers and gateways. 3GPP defines 5G private networks as non-public networks that typically employ a smaller-scale deployment to meet an organization's needs for reliability, accessibility, and maintainability. Open source private networks are based on a collaborative, community-driven software that relies on peer review and production to use, modify and share the source code. A global area network (GAN) is a network used for supporting mobile across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial wireless LANs . [ 14 ] Space networks are networks used for communication between spacecraft, usually in the vicinity of the Earth. The example of this is NASA's Space Network . Some examples of usage include cellular phones which are part of everyday wireless networks, allowing easy personal communications. Another example, Intercontinental network systems, use radio satellites to communicate across the world. Emergency services such as the police utilize wireless networks to communicate effectively as well. Individuals and businesses use wireless networks to send and share data rapidly, whether it be in a small office building or across the world. In a general sense, wireless networks offer a vast variety of uses by both business and home users. [ 15 ] "Now, the industry accepts a handful of different wireless technologies. Each wireless technology is defined by a standard that describes unique functions at both the Physical and the Data Link layers of the OSI model . These standards differ in their specified signaling methods, geographic ranges, and frequency usages, among other things. Such differences can make certain technologies better suited to home networks and others better suited to network larger organizations." [ 15 ] Each standard varies in geographical range, thus making one standard more ideal than the next depending on what it is one is trying to accomplish with a wireless network. [ 15 ] The performance of wireless networks satisfies a variety of applications such as voice and video. The use of this technology also gives room for expansions, such as from 2G to 3G and, 4G and 5G technologies, which stand for the fourth and fifth generation of cell phone mobile communications standards. As wireless networking has become commonplace, sophistication increases through configuration of network hardware and software, and greater capacity to send and receive larger amounts of data, faster, is achieved. Now the wireless network has been running on LTE, which is a 4G mobile communication standard. Users of an LTE network should have data speeds that are 10x faster than a 3G network. [ 16 ] Space is another characteristic of wireless networking. Wireless networks offer many advantages when it comes to difficult-to-wire areas trying to communicate such as across a street or river, a warehouse on the other side of the premises or buildings that are physically separated but operate as one. [ 16 ] Wireless networks allow for users to designate a certain space which the network will be able to communicate with other devices through that network. Space is also created in homes as a result of eliminating clutters of wiring. [ 17 ] This technology allows for an alternative to installing physical network mediums such as TPs , coaxes , or fiber-optics , which can also be expensive. For homeowners, wireless technology is an effective option compared to Ethernet for sharing printers, scanners, and high-speed Internet connections. WLANs help save the cost of installation of cable mediums, save time from physical installation, and also creates mobility for devices connected to the network. [ 17 ] Wireless networks are simple and require as few as one single wireless access point connected directly to the Internet via a router . [ 15 ] The telecommunications network at the physical layer also consists of many interconnected wireline network elements (NEs). These NEs can be stand-alone systems or products that are either supplied by a single manufacturer or are assembled by the service provider (user) or system integrator with parts from several different manufacturers. Wireless NEs are the products and devices used by a wireless carrier to provide support for the backhaul network as well as a mobile switching center (MSC). Reliable wireless service depends on the network elements at the physical layer to be protected against all operational environments and applications (see GR-3171, Generic Requirements for Network Elements Used in Wireless Networks – Physical Layer Criteria ). [ 18 ] What are especially important are the NEs that are located on the cell tower to the base station (BS) cabinet. The attachment hardware and the positioning of the antenna and associated closures and cables are required to have adequate strength, robustness, corrosion resistance, and resistance against wind, storms, icing, and other weather conditions. Requirements for individual components, such as hardware, cables, connectors, and closures, shall take into consideration the structure to which they are attached. Compared to wired systems, wireless networks are frequently subject to electromagnetic interference . This can be caused by other networks or other types of equipment that generate radio waves that are within, or close, to the radio bands used for communication. Interference can degrade the signal or cause the system to fail. [ 4 ] Some materials cause absorption of electromagnetic waves, preventing it from reaching the receiver, in other cases, particularly with metallic or conductive materials reflection occurs. This can cause dead zones where no reception is available. Aluminium foiled thermal isolation in modern homes can easily reduce indoor mobile signals by 10 dB frequently leading to complaints about the bad reception of long-distance rural cell signals. In multipath fading two or more different routes taken by the signal, due to reflections, can cause the signal to cancel out each other at certain locations, and to be stronger in other places ( upfade ). The hidden node problem occurs in some types of network when a node is visible from a wireless access point (AP), but not from other nodes communicating with that AP. This leads to difficulties in medium access control (collisions). The exposed terminal problem is when a node on one network is unable to send because of co-channel interference from a node that is on a different network. The wireless spectrum is a limited resource and shared by all nodes in the range of its transmitters. Bandwidth allocation becomes complex with multiple participating users. Often users are not aware that advertised numbers (e.g., for IEEE 802.11 equipment or LTE networks) are not their capacity, but shared with all other users and thus the individual user rate is far lower. With increasing demand, the capacity crunch is more and more likely to happen. User-in-the-loop (UIL) may be an alternative solution to ever upgrading to newer technologies for over-provisioning . Shannon's theorem can describe the maximum data rate of any single wireless link, which relates to the bandwidth in hertz and to the noise on the channel. One can greatly increase channel capacity by using MIMO techniques, where multiple aerials or multiple frequencies can exploit multiple paths to the receiver to achieve much higher throughput – by a factor of the product of the frequency and aerial diversity at each end. Under Linux, the Central Regulatory Domain Agent (CRDA) controls the setting of channels. [ 19 ] The total network bandwidth depends on how dispersive the medium is (more dispersive medium generally has better total bandwidth because it minimises interference), how many frequencies are available, how noisy those frequencies are, how many aerials are used and whether a directional antenna is in use, whether nodes employ power control and so on. Cellular wireless networks generally have good capacity, due to their use of directional aerials, and their ability to reuse radio channels in non-adjacent cells. Additionally, cells can be made very small using low power transmitters this is used in cities to give network capacity that scales linearly with population density. [ 4 ] Wireless access points are also often close to humans, but the drop off in power over distance is fast, following the inverse-square law . [ 20 ] The position of the United Kingdom 's Health Protection Agency (HPA) is that “...radio frequency (RF) exposures from WiFi are likely to be lower than those from mobile phones". It also saw “...no reason why schools and others should not use WiFi equipment". [ 21 ] In October 2007, the HPA launched a new "systematic" study into the effects of WiFi networks on behalf of the UK government, in order to calm fears that had appeared in the media in a recent period up to that time". [ 22 ] Dr Michael Clark, of the HPA, says published research on mobile phones and masts does not add up to an indictment of WiFi. [ 23 ]	https://en.wikipedia.org/wiki/Wireless_network
A wireless network interface controller ( WNIC ) is a network interface controller which connects to a wireless network , such as Wi-Fi , Bluetooth , or LTE (4G) or 5G rather than a wired network, such as an Ethernet network. A WNIC, just like other NICs, works on the layers 1 and 2 of the OSI model and uses an antenna to communicate via radio waves . A wireless network interface controller may be implemented as an expansion card and connected using PCI bus or PCIe bus, or connected via USB , PC Card , ExpressCard , Mini PCIe or M.2 . The low cost and ubiquity of the Wi-Fi standard means that many newer mobile computers have a wireless network interface built into the motherboard . The term is usually applied to IEEE 802.11 adapters; it may also apply to a NIC using protocols other than 802.11, such as one implementing Bluetooth connections. An 802.11 WNIC can operate in two modes known as infrastructure mode and ad hoc mode : The IEEE 802.11 standard sets out low-level specifications for how all 802.11 wireless networks operate. Earlier 802.11 interface controllers are usually only compatible with earlier variants of the standard, while newer cards support both current and old standards. Specifications commonly used in marketing materials for WNICs include: Most WNICs support one or more of 802.11, Bluetooth and 3GPP (2G, 3G, 4G, 5G) network standards. Wireless range may be substantially affected by objects in the way of the signal and by the quality of the antenna. Large electrical appliances, such as refrigerators, fuse boxes, metal plumbing, and air conditioning units can impede a wireless network signal. The theoretical maximum range of IEEE 802.11 is only reached under ideal circumstances and true effective range is typically about half of the theoretical range. [ 1 ] Specifically, the maximum throughput speed is only achieved at extremely close range (less than 25 feet (7.6 m) or so); at the outer reaches of a device's effective range, speed may decrease to around 1 Mbit/s before it drops out altogether. The reason is that wireless devices dynamically negotiate the top speed at which they can communicate without dropping too many data packets. In an 802.11 WNIC, the MAC Sublayer Management Entity (MLME) can be implemented either in the NIC's hardware or firmware, or in host-based software that is executed on the main CPU. A WNIC that implements the MLME function in hardware or firmware is called a FullMAC WNIC or a HardMAC NIC [ 2 ] and a NIC that implements it in host software is called a SoftMAC NIC. [ 3 ] A FullMAC device hides the complexity of the 802.11 protocol from the main CPU, instead providing an 802.3 (Ethernet) interface; a SoftMAC design implements only the timing-critical part of the protocol in hardware/firmware and the rest on the host. [ 4 ] FullMAC chips are typically used in mobile devices because: Popular example of FullMAC chips is the one implemented on the Raspberry Pi 3 . Linux kernel 's mac80211 framework provides capabilities for SoftMAC devices and additional capabilities (such as mesh networking, which is known as the IEEE 802.11s standard) for devices with limited functionality. [ 5 ] [ 3 ] FreeBSD also supports SoftMAC drivers. [ 6 ]	https://en.wikipedia.org/wiki/Wireless_network_interface_controller
A wireless site survey , sometimes called an RF (Radio Frequency) site survey or wireless survey, is the process of planning and designing a wireless network , to provide a wireless solution that will deliver the required wireless coverage, data rates, network capacity, roaming capability and quality of service (QoS). [ 1 ] The survey usually involves a site visit to test for RF interference , and to identify optimum installation locations for access points . This requires analysis of building floor plans, inspection of the facility, and use of site survey tools. Interviews with IT management and the end users of the wireless network are also important to determine the design parameters for the wireless network. As part of the wireless site survey, the effective range boundary is set, which defines the area over which signal levels needed support the intended application. This involves determining the minimum signal-to-noise ratio (SNR) needed to support performance requirements. Wireless site survey can also mean the walk-testing, auditing, analysis or diagnosis of an existing wireless network, particularly one which is not providing the level of service required. [ 1 ] Wireless site surveys are typically conducted using computer software that collects and analyses WLAN metrics and/or RF spectrum characteristics. Before a survey, a floor plan or site map is imported into a site survey application and calibrated to set scale. During a survey, a surveyor walks the facility with a portable computer that continuously records the data. The surveyor either marks the current position on the floor plan manually, by clicking on the floor plan, or uses a GPS receiver that automatically marks the current position if the survey is conducted outdoors. After a survey, data analysis is performed and survey results are documented in site survey reports generated by the application. The data is often presented along with a wireless heat map based on the recorded metrics. [ 2 ] All these data collection, analysis, and visualization tasks are highly automated in modern software. In the past, however, these tasks required manual data recording and processing. [ 3 ] [ 4 ] There are three main types of wireless site surveys: passive, active, and predictive. [ 5 ] During a passive survey, a site survey application passively listens to WLAN traffic to detect active access points, measure signal strength and noise level. However, the wireless adapter being used for a survey is not associated to any WLANs. For system design purposes, one or more temporary access points are deployed to identify and qualify access point locations. This used to be the most common method of pre-deployment Wi-Fi survey. During an active survey, the wireless adapter is associated with one or several access points to measure round-trip time, throughput rates, packet loss, and retransmissions. Active surveys are used to troubleshoot Wi-Fi networks or to verify performance post-deployment. During a predictive survey, a model of the RF environment is created using simulation tools. It is essential that the correct information on the environment is entered into the RF modeling tool, including location and RF characteristics of barriers like walls or large objects. Therefore, temporary access points or signal sources can be used to gather information on propagation in the environment. Virtual access points are then placed on the floor plan to estimate expected coverage and adjust their number and location. The value of a predictive survey as a design tool versus a passive survey done with only a few access point is that modeled interference can be taken into account in the design. Additionally, some survey application allow the user to collect RF spectrum data using portable hardware spectrum analyzers, which is beneficial in case of high RF interference from non-802.11 sources, such as microwave ovens or cordless phones. [ 6 ] [ 7 ] Depending on the survey type, a number of software and software/hardware options are available to WLAN surveyors. Passive and active surveys are performed using software and typically require only a compatible off-the-shelf Wi-Fi adapter; no additional specialized hardware is required. [ 2 ] Predictive surveys require no hardware at all, as no wireless data collection is needed. Currently, professional-level site survey applications exist primarily for Microsoft Windows . Some site survey applications for other platforms, including iOS and Android , also exist, however they are limited in functionality due to the limitations of the underlying platform API . For example, signal level measurements cannot be obtained on iOS without jailbreaking . [ 8 ] The feasibility of creating professional-level applications for non-Windows tablets is debated. [ 9 ] [ 10 ] Unlike passive and active surveys, RF spectrum surveys require specialized RF equipment. There are various types of spectrum analyzers ranging from large and expensive bench-top units to portable ("field units") and USB-based analyzers. Because portability is a decisive factor in conducting wireless site surveys, spectrum analyzers in USB form factor are widely used today. [ 5 ] They typically cover multiple bands; dual-band (2.4/5 GHz) and triple-band (2.4/5/6 GHz) models are available. A number of WLAN chipset manufacturers incorporate spectrum analysis into their chipset designs; [ 5 ] this functionality is integrated into some high-end enterprise-class Wi-Fi access points. [ 11 ] [ 12 ]	https://en.wikipedia.org/wiki/Wireless_site_survey
A Wireless Supplicant is a program that runs on a computer and is responsible for making login requests to a wireless network. [ 1 ] It handles passing the login and encryption credentials to the authentication server . It also handles roaming from one wireless access point to another, in order to maintain connectivity. This article about wireless technology is a stub . You can help Wikipedia by expanding it . This network -related software article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_supplicant
Wireless triangulation is a method of determining the location of wireless nodes using IEEE 802.11 standards. [ 1 ] It is normally implemented by measuring the RSSI signals strength. [ 2 ] This article about wireless technology is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wireless_triangulation
Wirelesspt is a non-commercial open grassroots initiative to support free computer networks that is not dependent of central infrastructure, corporation or entity which is done by the ordinary citizen provide free, open and democratic access to the highways of information technologies helping people and organizations implementing wireless networks that will benefit their communities. The project also invests in investigating free, open source, digital, information and telecommunication technologies as well as to promote, educate and supply technological information to teach and educate its surrounding social environment about the importance of online privacy and security. WirelessPT is also part of an international movement for wireless community networks in Europe. The Project counts with local communities and was started in the community of Moitas Venda in Portugal . The main goal of WirelessPT is to build a large scale free wireless Wi-Fi network that is decentralized and owned by those who run it and to support local communication. The project is governed by its own agreement which was inspired in the Pico peering Agreement where participants agree upon a network that is free from discrimination and upholds net neutrality . Among other communities like guifi.net and freifunk , WirelessPT has and shares similarities. Among several goals the project includes: Like many other free community-driven networks, Wirelesspt uses mesh technology to bring up ad hoc networks by interconnecting multiple Wireless LANs using mobile ad hoc network technology and a special routing software . If one of these routers fail, this special software automatically calculates a new path to the final destination. This software is called mvwrt firmware . It is based on OpenWrt and other free software such as LEDE and was specifically designed for the needs and challenges of the project. There are many different developed versions of the firmware depending on the hardware and protocols that local communities decide to use. Having previously tested olsr , WirelessPT decided to work with Ad Hoc and the B.A.T.M.A.N. routing protocol as the firmware base routing protocol . Founded in January 2011 in Portugal after 2 years of planning the project was first started by its founder with a setup of 9 nodes and 5 gateways in 3 weeks to cover an area of 6 square kilometres using ddwrt firmware. In 2013 the project developed its own firmware and expanded their nodes count as well as coverage until today and became a registered national trademark in 2016 after participating in the Battlemesh v9 event. The project is currently active and stable also because it very easy to install the wireless kit specifically created for non-tech-savvy users and with the use of the self-managed and auto configured firmware on off-the-shelf wireless routers a node is fully functional without human interaction soon as the firmware is uploaded to a node. During its development of the project, it also created one of the best sources of dyi wireless documentation that can be found online offering solutions for small to large projects.	https://en.wikipedia.org/wiki/Wirelesspt
Wirth's law is an adage on computer performance which states that software is getting slower more rapidly than hardware is becoming faster. The adage is named after Niklaus Wirth , a computer scientist who discussed it in his 1995 article "A Plea for Lean Software". [ 1 ] [ 2 ] Wirth attributed the saying to Martin Reiser , who in the preface to his book on the Oberon System wrote: "The hope is that the progress in hardware will cure all software ills. However, a critical observer may observe that software manages to outgrow hardware in size and sluggishness." [ 3 ] Other observers had noted this for some time before; indeed, the trend was becoming obvious as early as 1987. [ 4 ] He states two contributing factors to the acceptance of ever-growing software as: "rapidly growing hardware performance" and "customers' ignorance of features that are essential versus nice-to-have". [ 1 ] Enhanced user convenience and functionality supposedly justify the increased size of software, but Wirth argues that people are increasingly misinterpreting complexity as sophistication, that "these details are cute but not essential, and they have a hidden cost". [ 1 ] As a result, he calls for the creation of "leaner" software and pioneered the development of Oberon , a software system developed between 1986 and 1989 based on nothing but hardware. Its primary goal was to show that software can be developed with a fraction of the memory capacity and processor power usually required, without sacrificing flexibility, functionality, or user convenience. [ 1 ] The law was restated in 2009 and attributed to Google co-founder Larry Page . It has been referred to as Page's law . [ 5 ] The first use of that name is attributed to fellow Google co-founder Sergey Brin at the 2009 Google I/O Conference. [ 6 ] Other common forms use the names of the leading hardware and software companies of the 1990s, Intel and Microsoft , or their CEOs, Andy Grove and Bill Gates , for example "What Intel giveth, Microsoft taketh away" [ 7 ] and Andy and Bill's law : "What Andy giveth, Bill taketh away". [ 8 ] Gates's law ("The speed of software halves every 18 months" [ 9 ] ) is an anonymously coined variant on Wirth's law, its name referencing Bill Gates, [ 9 ] co-founder of Microsoft. It is an observation that the speed of commercial software generally slows by 50% every 18 months, thereby negating all the benefits of Moore's law . This could occur for a variety of reasons: feature creep , code cruft , developer laziness, lack of funding, forced updates, forced porting (to a newer OS or to support a new technology) or a management turnover whose design philosophy does not coincide with the previous manager. [ 10 ] May's law , named after David May , is a variant stating: "Software efficiency halves every 18 months, compensating Moore's law". [ 11 ]	https://en.wikipedia.org/wiki/Wirth's_law
In the mathematical field of analysis , the Wirtinger inequality is an important inequality for functions of a single variable, named after Wilhelm Wirtinger . It was used by Adolf Hurwitz in 1901 to give a new proof of the isoperimetric inequality for curves in the plane. A variety of closely related results are today known as Wirtinger's inequality, all of which can be viewed as certain forms of the Poincaré inequality . There are several inequivalent versions of the Wirtinger inequality: Despite their differences, these are closely related to one another, as can be seen from the account given below in terms of spectral geometry . They can also all be regarded as special cases of various forms of the Poincaré inequality , with the optimal Poincaré constant identified explicitly. The middle version is also a special case of the Friedrichs inequality , again with the optimal constant identified. The three versions of the Wirtinger inequality can all be proved by various means. This is illustrated in the following by a different kind of proof for each of the three Wirtinger inequalities given above. In each case, by a linear change of variables in the integrals involved, there is no loss of generality in only proving the theorem for one particular choice of L . Consider the first Wirtinger inequality given above. Take L to be 2π . Since Dirichlet's conditions are met, we can write and the fact that the average value of y is zero means that a 0 = 0 . By Parseval's identity , and and since the summands are all nonnegative, the Wirtinger inequality is proved. Furthermore, it is seen that equality holds if and only if a n = b n = 0 for all n ≥ 2 , which is to say that y ( x ) = a 1 sin x + b 1 cos x . This is equivalent to the stated condition by use of the trigonometric addition formulas . Consider the second Wirtinger inequality given above. [ 1 ] Take L to be π . Any differentiable function y ( x ) satisfies the identity Integration using the fundamental theorem of calculus and the boundary conditions y (0) = y (π) = 0 then shows This proves the Wirtinger inequality, since the second integral is clearly nonnegative. Furthermore, equality in the Wirtinger inequality is seen to be equivalent to y ′( x ) = y ( x ) cot x , the general solution of which (as computed by separation of variables ) is y ( x ) = c sin x for an arbitrary number c . There is a subtlety in the above application of the fundamental theorem of calculus, since it is not the case that y ( x ) 2 cot x extends continuously to x = 0 and x = π for every function y ( x ) . This is resolved as follows. It follows from the Hölder inequality and y (0) = 0 that which shows that as long as is finite, the limit of ⁠ 1 / x ⁠ y ( x ) 2 as x converges to zero is zero. Since cot x < ⁠ 1 / x ⁠ for small positive values of x , it follows from the squeeze theorem that y ( x ) 2 cot x converges to zero as x converges to zero. In exactly the same way, it can be proved that y ( x ) 2 cot x converges to zero as x converges to π . Consider the third Wirtinger inequality given above. Take L to be 1 . Given a continuous function f on [0, 1] of average value zero, let Tf denote the function u on [0, 1] which is of average value zero, and with u ′′ + f = 0 and u ′(0) = u ′(1) = 0 . From basic analysis of ordinary differential equations with constant coefficients , the eigenvalues of T are ( k π) −2 for nonzero integers k , the largest of which is then π −2 . Because T is a bounded and self-adjoint operator , it follows that for all f of average value zero, where the equality is due to integration by parts . Finally, for any continuously differentiable function y on [0, 1] of average value zero, let g n be a sequence of compactly supported continuously differentiable functions on (0, 1) which converge in L 2 to y ′ . Then define Then each y n has average value zero with y n ′(0) = y n ′(1) = 0 , which in turn implies that − y n ′′ has average value zero. So application of the above inequality to f = − y n ′′ is legitimate and shows that It is possible to replace y n by y , and thereby prove the Wirtinger inequality, as soon as it is verified that y n converges in L 2 to y . This is verified in a standard way, by writing and applying the Hölder or Jensen inequalities. This proves the Wirtinger inequality. In the case that y ( x ) is a function for which equality in the Wirtinger inequality holds, then a standard argument in the calculus of variations says that y must be a weak solution of the Euler–Lagrange equation y ′′( x ) + y ( x ) = 0 with y ′(0) = y ′(1) = 0 , and the regularity theory of such equations, followed by the usual analysis of ordinary differential equations with constant coefficients , shows that y ( x ) = c cos π x for some number c . To make this argument fully formal and precise, it is necessary to be more careful about the function spaces in question. [ 2 ] In the language of spectral geometry , the three versions of the Wirtinger inequality above can be rephrased as theorems about the first eigenvalue and corresponding eigenfunctions of the Laplace–Beltrami operator on various one-dimensional Riemannian manifolds : [ 3 ] These can also be extended to statements about higher-dimensional spaces. For example, the Riemannian circle may be viewed as the one-dimensional version of either a sphere , real projective space , or torus (of arbitrary dimension). The Wirtinger inequality, in the first version given here, can then be seen as the n = 1 case of any of the following: The second and third versions of the Wirtinger inequality can be extended to statements about first Dirichlet and Neumann eigenvalues of the Laplace−Beltrami operator on metric balls in Euclidean space : In the first form given above, the Wirtinger inequality can be used to prove the isoperimetric inequality for curves in the plane, as found by Adolf Hurwitz in 1901. [ 8 ] Let ( x , y ) be a differentiable embedding of the circle in the plane. Parametrizing the circle by [0, 2π] so that ( x , y ) has constant speed, the length L of the curve is given by and the area A enclosed by the curve is given (due to Stokes theorem ) by Since the integrand of the integral defining L is assumed constant, there is which can be rewritten as The first integral is clearly nonnegative. Without changing the area or length of the curve, ( x , y ) can be replaced by ( x , y + z ) for some number z , so as to make y have average value zero. Then the Wirtinger inequality can be applied to see that the second integral is also nonnegative, and therefore which is the isoperimetric inequality. Furthermore, equality in the isoperimetric inequality implies both equality in the Wirtinger inequality and also the equality x ′( t ) + y ( t ) = 0 , which amounts to y ( t ) = c 1 sin( t – α) and then x ( t ) = c 1 cos( t – α) + c 2 for arbitrary numbers c 1 and c 2 . These equations mean that the image of ( x , y ) is a round circle in the plane.	https://en.wikipedia.org/wiki/Wirtinger's_inequality_for_functions
In complex analysis of one and several complex variables , Wirtinger derivatives (sometimes also called Wirtinger operators [ 1 ] ), named after Wilhelm Wirtinger who introduced them in 1927 in the course of his studies on the theory of functions of several complex variables , are partial differential operators of the first order which behave in a very similar manner to the ordinary derivatives with respect to one real variable , when applied to holomorphic functions , antiholomorphic functions or simply differentiable functions on complex domains . These operators permit the construction of a differential calculus for such functions that is entirely analogous to the ordinary differential calculus for functions of real variables . [ 2 ] Wirtinger derivatives were used in complex analysis at least as early as in the paper ( Poincaré 1899 ), as briefly noted by Cherry & Ye (2001 , p. 31) and by Remmert (1991 , pp. 66–67). [ 3 ] In the third paragraph of his 1899 paper, [ 4 ] Henri Poincaré first defines the complex variable in C n {\displaystyle \mathbb {C} ^{n}} and its complex conjugate as follows Then he writes the equation defining the functions V {\displaystyle V} he calls biharmonique , [ 5 ] previously written using partial derivatives with respect to the real variables x k , y q {\displaystyle x_{k},y_{q}} with k , q {\displaystyle k,q} ranging from 1 to n {\displaystyle n} , exactly in the following way [ 6 ] This implies that he implicitly used definition 2 below: to see this it is sufficient to compare equations 2 and 2' of ( Poincaré 1899 , p. 112). Apparently, this paper was not noticed by early researchers in the theory of functions of several complex variables : in the papers of Levi-Civita (1905) , Levi (1910) (and Levi 1911 ) and of Amoroso (1912) all fundamental partial differential operators of the theory are expressed directly by using partial derivatives respect to the real and imaginary parts of the complex variables involved. In the long survey paper by Osgood (1966) (first published in 1913), [ 7 ] partial derivatives with respect to each complex variable of a holomorphic function of several complex variables seem to be meant as formal derivatives : as a matter of fact when Osgood expresses the pluriharmonic operator [ 8 ] and the Levi operator , he follows the established practice of Amoroso , Levi and Levi-Civita . According to Henrici (1993 , p. 294), a new step in the definition of the concept was taken by Dimitrie Pompeiu : in the paper ( Pompeiu 1912 ), given a complex valued differentiable function (in the sense of real analysis ) of one complex variable g ( z ) {\displaystyle g(z)} defined in the neighbourhood of a given point z 0 ∈ C , {\displaystyle z_{0}\in \mathbb {C} ,} he defines the areolar derivative as the following limit where Γ ( z 0 , r ) = ∂ D ( z 0 , r ) {\displaystyle \Gamma (z_{0},r)=\partial D(z_{0},r)} is the boundary of a disk of radius r {\displaystyle r} entirely contained in the domain of definition of g ( z ) , {\displaystyle g(z),} i.e. his bounding circle . [ 9 ] This is evidently an alternative definition of Wirtinger derivative respect to the complex conjugate variable : [ 10 ] it is a more general one, since, as noted a by Henrici (1993 , p. 294), the limit may exist for functions that are not even differentiable at z = z 0 . {\displaystyle z=z_{0}.} [ 11 ] According to Fichera (1969 , p. 28), the first to identify the areolar derivative as a weak derivative in the sense of Sobolev was Ilia Vekua . [ 12 ] In his following paper, Pompeiu (1913) uses this newly defined concept in order to introduce his generalization of Cauchy's integral formula , the now called Cauchy–Pompeiu formula . The first systematic introduction of Wirtinger derivatives seems due to Wilhelm Wirtinger in the paper Wirtinger 1927 in order to simplify the calculations of quantities occurring in the theory of functions of several complex variables : as a result of the introduction of these differential operators , the form of all the differential operators commonly used in the theory, like the Levi operator and the Cauchy–Riemann operator , is considerably simplified and consequently easier to handle. The paper is deliberately written from a formal point of view, i.e. without giving a rigorous derivation of the properties deduced. Despite their ubiquitous use, [ 13 ] it seems that there is no text listing all the properties of Wirtinger derivatives: however, fairly complete references are the short course on multidimensional complex analysis by Andreotti (1976 , pp. 3–5), [ 14 ] the monograph of Gunning & Rossi (1965 , pp. 3–6), [ 15 ] and the monograph of Kaup & Kaup (1983 , p. 2,4) [ 16 ] which are used as general references in this and the following sections. Definition 1. Consider the complex plane C ≡ R 2 = { ( x , y ) ∣ x , y ∈ R } {\displaystyle \mathbb {C} \equiv \mathbb {R} ^{2}=\{(x,y)\mid x,y\in \mathbb {R} \}} (in a sense of expressing a complex number z = x + i y {\displaystyle z=x+iy} for real numbers x {\displaystyle x} and y {\displaystyle y} ). The Wirtinger derivatives are defined as the following linear partial differential operators of first order: Clearly, the natural domain of definition of these partial differential operators is the space of C 1 {\displaystyle C^{1}} functions on a domain Ω ⊆ R 2 , {\displaystyle \Omega \subseteq \mathbb {R} ^{2},} but, since these operators are linear and have constant coefficients , they can be readily extended to every space of generalized functions . Definition 2. Consider the Euclidean space on the complex field C n = R 2 n = { ( x , y ) = ( x 1 , … , x n , y 1 , … , y n ) ∣ x , y ∈ R n } . {\displaystyle \mathbb {C} ^{n}=\mathbb {R} ^{2n}=\left\{\left(\mathbf {x} ,\mathbf {y} \right)=\left(x_{1},\ldots ,x_{n},y_{1},\ldots ,y_{n}\right)\mid \mathbf {x} ,\mathbf {y} \in \mathbb {R} ^{n}\right\}.} The Wirtinger derivatives are defined as the following linear partial differential operators of first order: { ∂ ∂ z 1 = 1 2 ( ∂ ∂ x 1 − i ∂ ∂ y 1 ) ⋮ ∂ ∂ z n = 1 2 ( ∂ ∂ x n − i ∂ ∂ y n ) , { ∂ ∂ z ¯ 1 = 1 2 ( ∂ ∂ x 1 + i ∂ ∂ y 1 ) ⋮ ∂ ∂ z ¯ n = 1 2 ( ∂ ∂ x n + i ∂ ∂ y n ) . {\displaystyle {\begin{cases}{\frac {\partial }{\partial z_{1}}}={\frac {1}{2}}\left({\frac {\partial }{\partial x_{1}}}-i{\frac {\partial }{\partial y_{1}}}\right)\\\qquad \vdots \\{\frac {\partial }{\partial z_{n}}}={\frac {1}{2}}\left({\frac {\partial }{\partial x_{n}}}-i{\frac {\partial }{\partial y_{n}}}\right)\\\end{cases}},\qquad {\begin{cases}{\frac {\partial }{\partial {\bar {z}}_{1}}}={\frac {1}{2}}\left({\frac {\partial }{\partial x_{1}}}+i{\frac {\partial }{\partial y_{1}}}\right)\\\qquad \vdots \\{\frac {\partial }{\partial {\bar {z}}_{n}}}={\frac {1}{2}}\left({\frac {\partial }{\partial x_{n}}}+i{\frac {\partial }{\partial y_{n}}}\right)\\\end{cases}}.} As for Wirtinger derivatives for functions of one complex variable, the natural domain of definition of these partial differential operators is again the space of C 1 {\displaystyle C^{1}} functions on a domain Ω ⊂ R 2 n , {\displaystyle \Omega \subset \mathbb {R} ^{2n},} and again, since these operators are linear and have constant coefficients , they can be readily extended to every space of generalized functions . When a function f {\displaystyle f} is complex differentiable at a point, the Wirtinger derivative ∂ f / ∂ z {\displaystyle \partial f/\partial z} agrees with the complex derivative d f / d z {\displaystyle df/dz} . This follows from the Cauchy-Riemann equations . For the complex function f ( z ) = u ( z ) + i v ( z ) {\displaystyle f(z)=u(z)+iv(z)} which is complex differentiable where the third equality uses the first definition of Wirtinger's derivatives for u {\displaystyle u} and v {\displaystyle v} . It can also be done through actual application of the Cauchy-Riemann equations. The final equality comes from it being one of four equivalent formulations of the complex derivative through partial derivatives of the components. The second Wirtinger derivative is also related with complex differentiation; ∂ f ∂ z ¯ = 0 {\displaystyle {\frac {\partial f}{\partial {\bar {z}}}}=0} is equivalent to the Cauchy-Riemann equations in a complex form. In the present section and in the following ones it is assumed that z ∈ C n {\displaystyle z\in \mathbb {C} ^{n}} is a complex vector and that z ≡ ( x , y ) = ( x 1 , … , x n , y 1 , … , y n ) {\displaystyle z\equiv (x,y)=(x_{1},\ldots ,x_{n},y_{1},\ldots ,y_{n})} where x , y {\displaystyle x,y} are real vectors , with n ≥ 1: also it is assumed that the subset Ω {\displaystyle \Omega } can be thought of as a domain in the real euclidean space R 2 n {\displaystyle \mathbb {R} ^{2n}} or in its isomorphic complex counterpart C n . {\displaystyle \mathbb {C} ^{n}.} All the proofs are easy consequences of definition 1 and definition 2 and of the corresponding properties of the derivatives (ordinary or partial ). Lemma 1. If f , g ∈ C 1 ( Ω ) {\displaystyle f,g\in C^{1}(\Omega )} and α , β {\displaystyle \alpha ,\beta } are complex numbers , then for i = 1 , … , n {\displaystyle i=1,\dots ,n} the following equalities hold Lemma 2. If f , g ∈ C 1 ( Ω ) , {\displaystyle f,g\in C^{1}(\Omega ),} then for i = 1 , … , n {\displaystyle i=1,\dots ,n} the product rule holds This property implies that Wirtinger derivatives are derivations from the abstract algebra point of view, exactly like ordinary derivatives are. This property takes two different forms respectively for functions of one and several complex variables : for the n > 1 case, to express the chain rule in its full generality it is necessary to consider two domains Ω ′ ⊆ C m {\displaystyle \Omega '\subseteq \mathbb {C} ^{m}} and Ω ″ ⊆ C p {\displaystyle \Omega ''\subseteq \mathbb {C} ^{p}} and two maps g : Ω ′ → Ω {\displaystyle g:\Omega '\to \Omega } and f : Ω → Ω ″ {\displaystyle f:\Omega \to \Omega ''} having natural smoothness requirements. [ 17 ] Lemma 3.1 If f , g ∈ C 1 ( Ω ) , {\displaystyle f,g\in C^{1}(\Omega ),} and g ( Ω ) ⊆ Ω , {\displaystyle g(\Omega )\subseteq \Omega ,} then the chain rule holds Lemma 3.2 If g ∈ C 1 ( Ω ′ , Ω ) {\displaystyle g\in C^{1}(\Omega ',\Omega )} and f ∈ C 1 ( Ω , Ω ″ ) , {\displaystyle f\in C^{1}(\Omega ,\Omega ''),} then for i = 1 , … , n {\displaystyle i=1,\dots ,n} the following form of the chain rule holds Lemma 4. If f ∈ C 1 ( Ω ) , {\displaystyle f\in C^{1}(\Omega ),} then for i = 1 , … , n {\displaystyle i=1,\dots ,n} the following equalities hold	https://en.wikipedia.org/wiki/Wirtinger_derivatives
In mathematics, the Wirtinger inequality , named after Wilhelm Wirtinger , is a fundamental result in complex linear algebra which relates the symplectic and volume forms of a hermitian inner product . It has important consequences in complex geometry , such as showing that the normalized exterior powers of the Kähler form of a Kähler manifold are calibrations . Consider a real vector space with positive-definite inner product g , symplectic form ω , and almost-complex structure J , linked by ω ( u , v ) = g ( J ( u ), v ) for any vectors u and v . Then for any orthonormal vectors v 1 , ..., v 2 k there is There is equality if and only if the span of v 1 , ..., v 2 k is closed under the operation of J . [ 1 ] In the language of the comass of a form, the Wirtinger theorem (although without precision about when equality is achieved) can also be phrased as saying that the comass of the form ω ∧ ⋅⋅⋅ ∧ ω is equal to k ! . [ 1 ] In the special case k = 1 , the Wirtinger inequality is a special case of the Cauchy–Schwarz inequality : According to the equality case of the Cauchy–Schwarz inequality, equality occurs if and only if J ( v 1 ) and v 2 are collinear, which is equivalent to the span of v 1 , v 2 being closed under J . Let v 1 , ..., v 2 k be fixed, and let T denote their span. Then there is an orthonormal basis e 1 , ..., e 2 k of T with dual basis w 1 , ..., w 2 k such that where ι denotes the inclusion map from T into V . [ 2 ] This implies which in turn implies where the inequality follows from the previously-established k = 1 case. If equality holds, then according to the k = 1 equality case, it must be the case that ω ( e 2 i − 1 , e 2 i ) = ±1 for each i . This is equivalent to either ω ( e 2 i − 1 , e 2 i ) = 1 or ω ( e 2 i , e 2 i − 1 ) = 1 , which in either case (from the k = 1 case) implies that the span of e 2 i − 1 , e 2 i is closed under J , and hence that the span of e 1 , ..., e 2 k is closed under J . Finally, the dependence of the quantity on v 1 , ..., v 2 k is only on the quantity v 1 ∧ ⋅⋅⋅ ∧ v 2 k , and from the orthonormality condition on v 1 , ..., v 2 k , this wedge product is well-determined up to a sign. This relates the above work with e 1 , ..., e 2 k to the desired statement in terms of v 1 , ..., v 2 k . Given a complex manifold with hermitian metric , the Wirtinger theorem immediately implies that for any 2 k -dimensional embedded submanifold M , there is where ω is the Kähler form of the metric. Furthermore, equality is achieved if and only if M is a complex submanifold . [ 3 ] In the special case that the hermitian metric satisfies the Kähler condition , this says that ⁠ 1 / k ! ⁠ ω k is a calibration for the underlying Riemannian metric, and that the corresponding calibrated submanifolds are the complex submanifolds of complex dimension k . [ 4 ] This says in particular that every complex submanifold of a Kähler manifold is a minimal submanifold , and is even volume-minimizing among all submanifolds in its homology class . Using the Wirtinger inequality, these facts even extend to the more sophisticated context of currents in Kähler manifolds. [ 5 ]	https://en.wikipedia.org/wiki/Wirtinger_inequality_(2-forms)
The Wisconsin Integrally Synchronized Computer (WISC) was an early digital computer designed and built at the University of Wisconsin–Madison . Operational in 1954, [ 1 ] it was the first digital computer in the state. Pioneering computer designer Gene Amdahl drafted the WISC's design as his PhD thesis. The computer was built over the period 1951-1954. It had 1,024 50-bit words (equivalent to about 6 KB) of drum memory , with an operation time of 1/15 second and throughput of 60 operations per second, which was achieved by an early form of instruction pipeline . [ 2 ] It was capable of both fixed and floating point operation. It weighed about 1 short ton (910 kg). [ 3 ] The WISC is part of the permanent collection of the Computer History Museum . [ 4 ] This computing article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wisconsin_Integrally_Synchronized_Computer
A wish list , wishlist or want list is a list of goods or services that a person or organization desires. The author may distribute copies of their list to family, friends, and other stakeholders who are likely to purchase gifts for the would-be recipient or to offer some of the listed items for sale. The goal of a wish list is to facilitate communication between the gift receiver and the gift giver. Wish lists often contain items that a gift purchaser can obtain from a variety of retailers. Some wish lists are specialized for particular purposes or concentrated at individual retailers, such as gift registries (e.g., bridal registries ). In some cultures, people often exchange wish lists before major holidays that include gift-giving, such as Christmas and birthdays . Other common occasions for issuing wish lists include baby showers , housewarmings , weddings , and charity drives . An online wish list typically allows a registered user to create a wish list, add wishes to it, and then spread a link to the wish list via email or social media like Facebook and Twitter . Visitors to the published wish list can in most cases comment wishes and reserve them. This adds a collaborative perspective among the viewers that would be much harder to achieve for analog wish lists. Online wish lists on retailer websites allow you to save items you prefer from that retailer's site for future reference. Universal online wish lists allow you to add items from multiple retailers and even non-retail ideas. Software user wish lists are a compilation of user suggestions for requested features. Many enterprise websites and software packages offer users the option to add a "wish" – a suggestion for improvement or change – and to vote on the importance of suggestions supplied by the publisher or author of the website or software, and they attempt to give a quick response to the suggestions. For example, Microsoft Visual Studio has a "community" menu, and Facebook has a "suggestions" section. In many cases, when a company fails to supply such a framework, users create their own lists, in Internet forums or in blogs . When such a list becomes popular, the company must respond to common requests. Having software user wish lists has become popular since 2007 when a football gaming community FIFPlay started collecting fans wishlist for Electronic Arts for pre-development of FIFA (video game series) and it has collected over 10,000 ideas and suggestions for FIFA 08 .	https://en.wikipedia.org/wiki/Wish_list
Wiswesser line notation (WLN) , invented by William J. Wiswesser in 1949, [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] was the first line notation capable of precisely describing complex molecules . It was the basis of ICI Ltd 's CROSSBOW database system developed in the late 1960s. WLN allowed for indexing the Chemical Structure Index (CSI) at the Institute for Scientific Information (ISI). It was also the tool used to develop the CAOCI (Commercially Available Organic Chemical Intermediates) database, the datafile from which Accelrys' (successor to MDL) ACD file was developed. WLN is still being extensively used by BARK Information Services. Descriptions of how to encode molecules as WLN have been published in several books. [ 6 ] [ 7 ] [ 8 ] This chemistry -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wiswesser_line_notation
Without loss of generality (often abbreviated to WOLOG , WLOG or w.l.o.g. ; less commonly stated as without any loss of generality or with no loss of generality ) is a frequently used expression in mathematics . The term is used to indicate the assumption that what follows is chosen arbitrarily, narrowing the premise to a particular case, but does not affect the validity of the proof in general. The other cases are sufficiently similar to the one presented that proving them follows by essentially the same logic. [ 1 ] As a result, once a proof is given for the particular case, it is trivial to adapt it to prove the conclusion in all other cases. In many scenarios, the use of "without loss of generality" is made possible by the presence of symmetry . [ 2 ] For example, if some property P ( x , y ) of real numbers is known to be symmetric in x and y , namely that P ( x , y ) is equivalent to P ( y , x ), then in proving that P ( x , y ) holds for every x and y , one may assume "without loss of generality" that x ≤ y . There is no loss of generality in this assumption, since once the case x ≤ y ⇒ P ( x , y ) has been proved, the other case follows by interchanging x and y : y ≤ x ⇒ P ( y , x ), and by symmetry of P , this implies P ( x , y ), thereby showing that P ( x , y ) holds for all cases. On the other hand, if neither such a symmetry nor another form of equivalence can be established, then the use of "without loss of generality" is incorrect and can amount to an instance of proof by example – a logical fallacy of proving a claim by proving a non-representative example. [ 3 ] Consider the following theorem (which is a case of the pigeonhole principle ): If three objects are each painted either red or blue, then there must be at least two objects of the same color. A proof: Assume, without loss of generality, that the first object is red. If either of the other two objects is red, then we are finished; if not, then the other two objects must both be blue and we are still finished. The above argument works because the exact same reasoning could be applied if the alternative assumption, namely, that the first object is blue, were made, or, similarly, that the words 'red' and 'blue' can be freely exchanged in the wording of the proof. As a result, the use of "without loss of generality" is valid in this case.	https://en.wikipedia.org/wiki/Without_loss_of_generality
In mathematical logic , a witness is a specific value t to be substituted for variable x of an existential statement of the form ∃ x φ ( x ) such that φ ( t ) is true. For example, a theory T of arithmetic is said to be inconsistent if there exists a proof in T of the formula "0 = 1". The formula I( T ), which says that T is inconsistent, is thus an existential formula. A witness for the inconsistency of T is a particular proof of "0 = 1" in T . Boolos, Burgess, and Jeffrey (2002:81) define the notion of a witness with the example, in which S is an n -place relation on natural numbers, R is an (n+1) -place recursive relation , and ↔ indicates logical equivalence (if and only if): In this particular example, the authors defined s to be (positively) recursively semidecidable , or simply semirecursive . In predicate calculus , a Henkin witness for a sentence ∃ x φ ( x ) {\displaystyle \exists x\,\varphi (x)} in a theory T is a term c such that T proves φ ( c ) (Hinman 2005:196). The use of such witnesses is a key technique in the proof of Gödel's completeness theorem presented by Leon Henkin in 1949. The notion of witness leads to the more general idea of game semantics . In the case of sentence ∃ x φ ( x ) {\displaystyle \exists x\,\varphi (x)} the winning strategy for the verifier is to pick a witness for φ {\displaystyle \varphi } . For more complex formulas involving universal quantifiers , the existence of a winning strategy for the verifier depends on the existence of appropriate Skolem functions . For example, if S denotes ∀ x ∃ y φ ( x , y ) {\displaystyle \forall x\,\exists y\,\varphi (x,y)} then an equisatisfiable statement for S is ∃ f ∀ x φ ( x , f ( x ) ) {\displaystyle \exists f\,\forall x\,\varphi (x,f(x))} . The Skolem function f (if it exists) actually codifies a winning strategy for the verifier of S by returning a witness for the existential sub-formula for every choice of x the falsifier might make.	https://en.wikipedia.org/wiki/Witness_(mathematics)
Witold Filipowicz (born August 8, 1943 in Warsaw, Poland) - Polish-Swiss biochemist and molecular biologist . Filipowicz studied at the Faculty of Medicine of the Medical University of Lodz . [ 1 ] He received his PhD and habilitation at the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences (PAS) in Warsaw. [ 1 ] This was followed by the post-doctoral studies at the New York University Medical School and Roche Institute of Molecular Biology in Nutley, NJ (laboratories of Severo Ochoa and Aaron J. Shatkin . [ 2 ] Since 1984, he has been the head of the laboratory at the Friedrich Miescher Institute for Biomedical Research in Basel , Switzerland (currently emeritus). [ 2 ] Since 1991, Professor of Biological Sciences at PAN, and since 1997, Professor (now emeritus) of the University of Basel . [ 1 ] He has trained over 50 PhD students and post-doctoral scholars. Research of Filipowicz has focused on mechanisms of maturation and function of different classes of RNA molecules and ribonucleoprotein particles (RNPs), enzymes involved in RNA metabolism, mechanisms of protein synthesis, and mechanisms of RNA interference (RNAi) and microRNA (miRNA) function in mammalian cells. [ 3 ] Filipowicz has more than 47,000 citations on Google Scholar.	https://en.wikipedia.org/wiki/Witold_Filipowicz
In algebraic geometry , the Witten conjecture is a conjecture about intersection numbers of stable classes on the moduli space of curves , introduced by Edward Witten in the paper Witten ( 1991 ), and generalized in Witten (1993) . Witten's original conjecture was proved by Maxim Kontsevich in the paper Kontsevich (1992) . Witten's motivation for the conjecture was that two different models of 2-dimensional quantum gravity should have the same partition function . The partition function for one of these models can be described in terms of intersection numbers on the moduli stack of algebraic curves , and the partition function for the other is the logarithm of the τ-function of the KdV hierarchy . Identifying these partition functions gives Witten's conjecture that a certain generating function formed from intersection numbers should satisfy the differential equations of the KdV hierarchy. Suppose that M g , n is the moduli stack of compact Riemann surfaces of genus g with n distinct marked points x 1 ,..., x n , and M g , n is its Deligne–Mumford compactification. There are n line bundles L i on M g , n , whose fiber at a point of the moduli stack is given by the cotangent space of a Riemann surface at the marked point x i . The intersection index 〈τ d 1 , ..., τ d n 〉 is the intersection index of Π c 1 ( L i ) d i on M g , n where Σ d i = dim M g , n = 3 g – 3 + n , and 0 if no such g exists, where c 1 is the first Chern class of a line bundle. Witten's generating function encodes all the intersection indices as its coefficients. Witten's conjecture states that the partition function Z = exp F is a τ-function for the KdV hierarchy , in other words it satisfies a certain series of partial differential equations corresponding to the basis { L − 1 , L 0 , L 1 , … } {\displaystyle \{L_{-1},L_{0},L_{1},\ldots \}} of the Virasoro algebra . Kontsevich used a combinatorial description of the moduli spaces in terms of ribbon graphs to show that Here the sum on the right is over the set G g , n of ribbon graphs X of compact Riemann surfaces of genus g with n marked points. The set of edges e and points of X are denoted by X 0 and X 1 . The function λ is thought of as a function from the marked points to the reals, and extended to edges of the ribbon graph by setting λ of an edge equal to the sum of λ at the two marked points corresponding to each side of the edge. By Feynman diagram techniques, this implies that F ( t 0 ,...) is an asymptotic expansion of as Λ tends to infinity, where Λ and Χ are positive definite N by N hermitian matrices, and t i is given by and the probability measure μ on the positive definite hermitian matrices is given by where c Λ is a normalizing constant. This measure has the property that which implies that its expansion in terms of Feynman diagrams is the expression for F in terms of ribbon graphs. From this he deduced that exp F is a τ-function for the KdV hierarchy, thus proving Witten's conjecture. The Witten conjecture is a special case of a more general relation between integrable systems of Hamiltonian PDEs and the geometry of certain families of 2D topological field theories (axiomatized in the form of the so-called cohomological field theories by Kontsevich and Manin), which was explored and studied systematically by B. Dubrovin and Y. Zhang, A. Givental, C. Teleman and others. The Virasoro conjecture is a generalization of the Witten conjecture.	https://en.wikipedia.org/wiki/Witten_conjecture
In quantum field theory and statistical mechanics , the Witten index at the inverse temperature β is defined as a modification of the standard partition function : Note the (-1) F operator, where F is the fermion number operator . This is what makes it different from the ordinary partition function . It is sometimes referred to as the spectral asymmetry . In a supersymmetric theory, each nonzero energy eigenvalue contains an equal number of bosonic and fermionic states. Because of this, the Witten index is independent of the temperature and gives the number of zero energy bosonic vacuum states minus the number of zero energy fermionic vacuum states. In particular, if supersymmetry is spontaneously broken then there are no zero energy ground states and so the Witten index is equal to zero. The Witten index of the supersymmetric sigma model on a manifold is given by the manifold's Euler characteristic . [ 1 ] It is an example of a quasi-topological quantity, which is a quantity that depends only on F-terms and not on D-terms in the Lagrangian . A more refined invariant in 2-dimensional theories, constructed using only the right-moving part of the fermion number operator together with a 2-parameter family of variations, is the elliptic genus . This article about statistical mechanics is a stub . You can help Wikipedia by expanding it . This quantum mechanics -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Witten_index
In mathematics , the Witten zeta function , is a function associated to a root system that encodes the degrees of the irreducible representations of the corresponding Lie group . These zeta functions were introduced by Don Zagier who named them after Edward Witten's study of their special values (among other things). [ 1 ] [ 2 ] Note that in, [ 2 ] Witten zeta functions do not appear as explicit objects in their own right. If G {\displaystyle G} is a compact semisimple Lie group, the associated Witten zeta function is (the meromorphic continuation of) the series where the sum is over equivalence classes of irreducible representations of G {\displaystyle G} . In the case where G {\displaystyle G} is connected and simply connected, the correspondence between representations of G {\displaystyle G} and of its Lie algebra, together with the Weyl dimension formula, implies that ζ G ( s ) {\displaystyle \zeta _{G}(s)} can be written as where Φ + {\displaystyle \Phi ^{+}} denotes the set of positive roots, { λ i } {\displaystyle \{\lambda _{i}\}} is a set of simple roots and r {\displaystyle r} is the rank. If G {\displaystyle G} is simple and simply connected, the abscissa of convergence of ζ G ( s ) {\displaystyle \zeta _{G}(s)} is r / κ {\displaystyle r/\kappa } , where r {\displaystyle r} is the rank and κ = \| Φ + \| {\displaystyle \kappa =\|\Phi ^{+}\|} . This is a theorem due to Alex Lubotzky and Michael Larsen. [ 3 ] A new proof is given by Jokke Häsä and Alexander Stasinski [ 4 ] which yields a more general result, namely it gives an explicit value (in terms of simple combinatorics) of the abscissa of convergence of any "Mellin zeta function" of the form ∑ x 1 , … , x r = 1 ∞ 1 P ( x 1 , … , x r ) s , {\displaystyle \sum _{x_{1},\dots ,x_{r}=1}^{\infty }{\frac {1}{P(x_{1},\dots ,x_{r})^{s}}},} where P ( x 1 , … , x r ) {\displaystyle P(x_{1},\dots ,x_{r})} is a product of linear polynomials with non-negative real coefficients. ζ S U ( 3 ) {\displaystyle \zeta _{SU(3)}} is absolutely convergent in { s ∈ C , ℜ ( s ) > 2 / 3 } {\displaystyle \{s\in \mathbb {C} ,\Re (s)>2/3\}} , and it can be extended meromorphicaly in C {\displaystyle \mathbb {C} } . Its singularities are in { 2 3 } ∪ { 1 2 − k , k ∈ N } , {\displaystyle {\Bigl \{}{\frac {2}{3}}{\Bigr \}}\cup {\Bigl \{}{\frac {1}{2}}-k,k\in \mathbb {N} {\Bigr \}},} and all of those singularities are simple poles. [ 5 ] In particular, the values of ζ S U ( 3 ) ( s ) {\displaystyle \zeta _{SU(3)}(s)} are well defined at all integers, and have been computed by Kazuhiro Onodera. [ 6 ] At s = 0 {\displaystyle s=0} , we have ζ S U ( 3 ) ( 0 ) = 1 3 , {\displaystyle \zeta _{SU(3)}(0)={\frac {1}{3}},} and ζ S U ( 3 ) ′ ( 0 ) = log ⁡ ( 2 4 / 3 π ) . {\displaystyle \zeta _{SU(3)}'(0)=\log(2^{4/3}\pi ).} Let a ∈ N ∗ {\displaystyle a\in \mathbb {N} ^{*}} be a positive integer. We have ζ S U ( 3 ) ( a ) = 2 a + 2 1 + ( − 1 ) a 2 ∑ k = 0 [ a / 2 ] ( 2 a − 2 k − 1 a − 1 ) ζ ( 2 k ) ζ ( 3 a − k ) . {\displaystyle \zeta _{SU(3)}(a)={\frac {2^{a+2}}{1+(-1)^{a}2}}\sum _{k=0}^{[a/2]}{2a-2k-1 \choose a-1}\zeta (2k)\zeta (3a-k).} If a is odd, then ζ S U ( 3 ) {\displaystyle \zeta _{SU(3)}} has a simple zero at s = − a , {\displaystyle s=-a,} and ζ S U ( 3 ) ′ ( − a ) = 2 − a + 1 ( a ! ) 2 ( 2 a + 1 ) ! ζ ′ ( − 3 a − 1 ) + 2 − a + 2 ∑ k = 0 ( a − 1 ) / 2 ( a 2 k ) ζ ( − a − 2 k ) ζ ′ ( − 2 a + 2 k ) . {\displaystyle \zeta _{SU(3)}'(-a)={\frac {2^{-a+1}(a!)^{2}}{(2a+1)!}}\zeta '(-3a-1)+2^{-a+2}\sum _{k=0}^{(a-1)/2}{a \choose 2k}\zeta (-a-2k)\zeta '(-2a+2k).} If a is even, then ζ S U ( 3 ) {\displaystyle \zeta _{SU(3)}} has a zero of order 2 {\displaystyle 2} at s = − a , {\displaystyle s=-a,} and ζ S U ( 3 ) ″ ( − a ) = 2 − a + 2 ∑ k = 0 a / 2 ( a 2 k ) ζ ′ ( − a − 2 k ) ζ ′ ( − 2 a + 2 k ) . {\displaystyle \zeta _{SU(3)}''(-a)=2^{-a+2}\sum _{k=0}^{a/2}{a \choose 2k}\zeta '(-a-2k)\zeta '(-2a+2k).} This algebra -related article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Witten_zeta_function
The Wittig reaction or Wittig olefination is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide called a Wittig reagent . Wittig reactions are most commonly used to convert aldehydes and ketones to alkenes. [ 1 ] [ 2 ] [ 3 ] Most often, the Wittig reaction is used to introduce a methylene group using methylenetriphenylphosphorane (Ph 3 P=CH 2 ). Using this reagent, even a sterically hindered ketone such as camphor can be converted to its methylene derivative. Mechanistic studies have focused on unstabilized ylides, because the intermediates can be followed by NMR spectroscopy . The existence and interconversion of the betaine ( 3a and 3b ) is subject of ongoing research. [ 4 ] For lithium-free Wittig reactions, studies support a concerted formation of the oxaphosphetane without intervention of a betaine. In particular, phosphonium ylides 1 react with carbonyl compounds 2 via a [2+2] cycloaddition that is sometimes described as having [ π 2 s + π 2 a ] topology to directly form the oxaphosphetanes 4a and 4b . Under lithium-free conditions, the stereochemistry of the product 5 is due to the kinetically controlled addition of the ylide 1 to the carbonyl 2 . When lithium is present, there may be equilibration of the intermediates, possibly via betaine species 3a and 3b . [ 5 ] [ 6 ] [ 7 ] Bruce E. Maryanoff and A. B. Reitz identified the issue about equilibration of Wittig intermediates and termed the process "stereochemical drift". For many years, the stereochemistry of the Wittig reaction, in terms of carbon-carbon bond formation, had been assumed to correspond directly with the Z/E stereochemistry of the alkene products. However, certain reactants do not follow this simple pattern. Lithium salts can also exert a profound effect on the stereochemical outcome. [ 8 ] Mechanisms differ for aliphatic and aromatic aldehydes and for aromatic and aliphatic phosphonium ylides. Evidence suggests that the Wittig reaction of unbranched aldehydes under lithium-salt-free conditions do not equilibrate and are therefore under kinetic reaction control . [ 9 ] [ 10 ] E. Vedejs has put forth a theory to explain the stereoselectivity of stabilized and unstabilized Wittig reactions. [ 11 ] Strong evidence indicated that under Li-free conditions, Wittig reactions involving unstabilized (R 1 = alkyl, H), semistabilized (R 1 = aryl), and stabilized (R 1 = EWG) Wittig reagents all proceed via a [2+2]/retro-[2+2] mechanism under kinetic control, with oxaphosphetane as the one and only intermediate. [ 12 ] The Wittig reagents generally tolerate carbonyl compounds containing several kinds of functional groups such as OH , OR , nitroarenes , epoxides , and sometimes esters and amides . [ 13 ] Even ketone , aldehyde , and nitrile groups can be present if conjugated with the ylide — these are the stabilised ylides mentioned above. Bis-ylides (containing two P=C bonds) have also been made and used successfully. [ 14 ] There can be a problem with sterically hindered ketones, where the reaction may be slow and give poor yields, particularly with stabilized ylides, and in such cases the Horner–Wadsworth–Emmons (HWE) reaction (using phosphonate esters) is preferred. Another reported limitation is the often labile nature of aldehydes , which can oxidize, polymerize or decompose. In a so-called tandem oxidation-Wittig process the aldehyde is formed in situ by oxidation of the corresponding alcohol. [ 15 ] For the reaction with aldehydes, the double bond geometry is readily predicted based on the nature of the ylide. With unstabilised ylides (R 3 = alkyl) this results in ( Z )-alkene product with moderate to high selectivity. If the reaction is performed in dimethylformamide in the presence of lithium iodide or sodium iodide , the product is almost exclusively the Z-isomer. [ 16 ] With stabilized ylides (R 3 = ester or ketone), the ( E )-alkene is formed with high selectivity. The ( E )/( Z ) selectivity is often poor with semistabilized ylides (R 3 = aryl). [ 17 ] To obtain the ( E )-alkene for unstabilized ylides, the Schlosser modification of the Wittig reaction can be used. Alternatively, the Julia olefination and its variants also provide the ( E )-alkene selectively. Ordinarily, the Horner–Wadsworth–Emmons reaction provides the ( E )-enoate (α,β-unsaturated ester), just as the Wittig reaction does. To obtain the ( Z )-enolate, the Still-Gennari modification of the Horner-Wadsworth-Emmons reaction can be used. The main limitation of the traditional Wittig reaction is that the reaction proceeds mainly via the erythro betaine intermediate, which leads to the Z-alkene. The erythro betaine can be converted to the threo betaine using phenyllithium at low temperature. [ 18 ] This modification affords the E-alkene. Allylic alcohols can be prepared by reaction of the betaine ylide with a second aldehyde. [ 19 ] For example: An example of its use is in the synthesis of leukotriene A methyl ester. [ 20 ] [ 21 ] The first step uses a stabilised ylide, where the carbonyl group is conjugated with the ylide preventing self condensation, although unexpectedly this gives mainly the cis product. The second Wittig reaction uses a non-stabilised Wittig reagent, and as expected this gives mainly the cis product. The Wittig reaction was reported in 1954 by Georg Wittig and his coworker Ulrich Schöllkopf . In part for this contribution, Wittig was awarded the Nobel Prize in Chemistry in 1979. [ 22 ] [ 23 ]	https://en.wikipedia.org/wiki/Wittig_reaction
Wizards of OS (Wizards of Operating Systems, or "WOS") was a semi-annual Berlin -based conference that was held four times between 1999 and 2006. Its topics were the cultural and political potentials of free software , software technology, digital networks and media, and more generally information freedom and open cooperation in the creation and proliferation of knowledge. The conference was interdisciplinary, and included among its attendees scientists, engineers, social researchers, scholars from the humanities, artists and activists. The name was a word play on The Wizard of Oz . The acronym "OS" stands for operating system (not open source ). The first Wizards of OS conference took place in 1999. The third conference took place in 2004, with the subtitle "The Future of the Digital Commons". It featured, among others, the launch of the German translation of the Creative Commons licenses. Wizards of OS 4 took place from September 14 to September 16, 2006, with the subtitle "Information Freedom Rules". Some of the topics were the future of Creative Commons , open music and the compensation of artists and European copyright legislation . Larry Sanger announced an initial proposal of his project Citizendium . [ 1 ]	https://en.wikipedia.org/wiki/Wizards_of_OS
wm2 is a minimalist reparenting window manager for the X Window System written by Chris Cannam. wm2 was released around 1997 and was inspired by the window manager from the operating system Plan 9 . [ 3 ] wm2 was designed to have a simple set of features and be fast. It provides support for moving, resizing, and deleting windows , but does not support desktop icons , menus, toolbars, panels, or docks. [ 4 ] Instead of icons, wm2 allows temporary hiding of windows from the desktop environment . Hidden windows can be recovered via a menu from the root window . It does not support interactive configuration, or provide a virtual desktop, and other features of modern window managers such as configurable root menus , toolbars , etc. Configuration options require editing and recompiling a source file and few options are available. [ 5 ] [ 6 ] wm2 is intended to be configuration free. [ 7 ] wmx is a version of wm2 modified to add experimental features otherwise not supported in wm2. [ 8 ] [ 9 ] wm2 was noted as being "very spartan", "bare-bones", and minimalist, though opinions on it were positive as it is allows for easy access to X11 and window management without too much configuration. [ 6 ] [ 10 ] [ 11 ] One author noted it used less memory than the other options he tried, getting it to run with only 0.7MB of memory. [ 4 ] This computing article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wm2
wmctrl is a command used to control windows in EWMH - and NetWM -compatible X Window window managers . Some of its common operations are list, resize, and close window. It also has the ability to interact with virtual desktops and give information about the window manager. wmctrl is a command-line program , however, it has some functions that allow the mouse to select a window for an operation. [ 1 ] wmctrl operations [ 1 ] Compatible, or mostly compatible, window managers [ 2 ]	https://en.wikipedia.org/wiki/Wmctrl
Wnn ( Japanese pronunciation: [ɯnnɯ] or [ɯːnnɯ] ) is a Japanese input system . The network-extensible Kana -to- Kanji conversion system was jointly developed and released by the Software Research Group of Kyoto University Research Institute for Mathematical Sciences , Omron Tateisi Electronics Co., and Astec, Inc. It is distributed as freeware with a licence allowing users to copy and modify the software; however, it is not free software since certain restrictions are placed on the user, including a prohibition on changing the name. The licence is otherwise similar to the (old, containing the advertising clause) BSD licence . Wnn is used as part of several programs that deal with Japanese text, including JWPce and NJStar 's Japanese Word Processor. The name is derived from the Japanese phrase " W atashi no n amae wa N akano desu" (my name is Nakano), as a design goal of the Wnn project was to be able to enter such a sentence, and have the correct kanji and kana [私の名前は中野です] selected automatically. Wnn is maintained by the FreeWnn project. This software article is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Wnn
In cellular biology, the Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors . The name Wnt, pronounced "wint", is a portmanteau created from the names Wingless and Int-1. [ 1 ] Wnt signaling pathways use either nearby cell-cell communication ( paracrine ) or same-cell communication ( autocrine ). They are highly evolutionarily conserved in animals, which means they are similar across animal species from fruit flies to humans. [ 2 ] [ 3 ] Three Wnt signaling pathways have been characterized: the canonical Wnt pathway , the noncanonical planar cell polarity pathway , and the noncanonical Wnt/calcium pathway . All three pathways are activated by the binding of a Wnt-protein ligand to a Frizzled family receptor , which passes the biological signal to the Dishevelled protein inside the cell. The canonical Wnt pathway leads to regulation of gene transcription , and is thought to be negatively regulated in part by the SPATS1 gene. [ 4 ] The noncanonical planar cell polarity pathway regulates the cytoskeleton that is responsible for the shape of the cell. The noncanonical Wnt/calcium pathway regulates calcium inside the cell. Wnt signaling was first identified for its role in carcinogenesis , then for its function in embryonic development . The embryonic processes it controls include body axis patterning, cell fate specification, cell proliferation and cell migration . These processes are necessary for proper formation of important tissues including bone, heart and muscle. Its role in embryonic development was discovered when genetic mutations in Wnt pathway proteins produced abnormal fruit fly embryos . Later research found that the genes responsible for these abnormalities also influenced breast cancer development in mice. Wnt signaling also controls tissue regeneration in adult bone marrow, skin and intestine. [ 5 ] This pathway's clinical importance was demonstrated by mutations that lead to various diseases, including breast and prostate cancer , glioblastoma , type II diabetes and others. [ 6 ] [ 7 ] In recent years, researchers reported first successful use of Wnt pathway inhibitors in mouse models of disease. [ 8 ] The discovery of Wnt signaling was influenced by research on oncogenic (cancer-causing) retroviruses . In 1982, Roel Nusse and Harold Varmus infected mice with mouse mammary tumor virus in order to mutate mouse genes to see which mutated genes could cause breast tumors. They identified a new mouse proto-oncogene that they named int1 (integration 1). [ 3 ] [ 9 ] Int1 is highly conserved across multiple species, including humans and Drosophila . Its presence in D. melanogaster led researchers to discover in 1987 that the int1 gene in Drosophila was actually the already known and characterized Drosophila gene known as Wingless (Wg). [ 3 ] Since previous research by Christiane Nüsslein-Volhard and Eric Wieschaus (which won them the Nobel Prize in Physiology or Medicine in 1995) had already established the function of Wg as a segment polarity gene involved in the formation of the body axis during embryonic development , researchers determined that the mammalian int1 discovered in mice is also involved in embryonic development. [ 10 ] Continued research led to the discovery of further int1-related genes; however, because those genes were not identified in the same manner as int1, the int gene nomenclature was inadequate. Thus, the int/Wingless family became the Wnt family and int1 became Wnt1. The name Wnt is a portmanteau of int and Wg and stands for "Wingless-related integration site". [ 3 ] Wnt comprises a diverse family of secreted lipid -modified signaling glycoproteins that are 350–400 amino acids in length. [ 11 ] The lipid modification of all Wnts is palmitoleoylation of a single totally conserved cysteine residue. [ 12 ] Palmitoleoylation is necessary because it is required for Wnt to bind to its carrier protein Wntless (WLS) so it can be transported to the plasma membrane for secretion [ 13 ] and it allows the Wnt protein to bind its receptor Frizzled [ 14 ] [ 15 ] Wnt proteins also undergo glycosylation , which attaches a carbohydrate in order to ensure proper secretion. [ 16 ] In Wnt signaling, these proteins act as ligands to activate the different Wnt pathways via paracrine and autocrine routes. [ 2 ] [ 7 ] These proteins are highly conserved across species. [ 3 ] They can be found in mice, humans, Xenopus , zebrafish , Drosophila and many others. [ 17 ] Wnt signaling begins when a Wnt protein binds to the N-terminal extra-cellular cysteine-rich domain of a Frizzled (Fz) family receptor. [ 19 ] These receptors span the plasma membrane seven times and constitute a distinct family of G-protein coupled receptors (GPCRs). [ 20 ] However, to facilitate Wnt signaling, co-receptors may be required alongside the interaction between the Wnt protein and Fz receptor. Examples include lipoprotein receptor-related protein ( LRP )-5/6, receptor tyrosine kinase (RTK), and ROR2 . [ 7 ] Upon activation of the receptor, a signal is sent to the phosphoprotein Dishevelled (Dsh), which is located in the cytoplasm . This signal is transmitted via a direct interaction between Fz and Dsh. Dsh proteins are present in all organisms and they all share the following highly conserved protein domains : an amino-terminal DIX domain, a central PDZ domain , and a carboxy-terminal DEP domain . These different domains are important because after Dsh, the Wnt signal can branch off into multiple pathways and each pathway interacts with a different combination of the three domains. [ 21 ] The three best characterized Wnt signaling pathways are the canonical Wnt pathway, the noncanonical planar cell polarity pathway, and the noncanonical Wnt/calcium pathway. As their names suggest, these pathways belong to one of two categories: canonical or noncanonical. The difference between the categories is that a canonical pathway involves the protein beta-catenin (β-catenin) while a noncanonical pathway operates independently of it. [ 19 ] The canonical Wnt pathway (or Wnt/ β-catenin pathway) is the Wnt pathway that causes an accumulation of β-catenin in the cytoplasm and its eventual translocation into the nucleus to act as a transcriptional coactivator of transcription factors that belong to the TCF/LEF family . Without Wnt, β-catenin would not accumulate in the cytoplasm since a destruction complex would normally degrade it. This destruction complex includes the following proteins: Axin , adenomatosis polyposis coli (APC), protein phosphatase 2A (PP2A), glycogen synthase kinase 3 (GSK3) and casein kinase 1 α (CK1α). [ 22 ] [ 23 ] It degrades β-catenin by targeting it for ubiquitination , which subsequently sends it to the proteasome to be digested. [ 19 ] [ 24 ] However, as soon as Wnt binds Fz and LRP5 / 6 , the destruction complex function becomes disrupted. This is due to Wnt causing the translocation of the negative Wnt regulator, Axin, and the destruction complex to the plasma membrane. Phosphorylation by other proteins in the destruction complex subsequently binds Axin to the cytoplasmic tail of LRP5/6. Axin becomes de-phosphorylated and its stability and levels decrease. Dsh then becomes activated via phosphorylation and its DIX and PDZ domains inhibit the GSK3 activity of the destruction complex. This allows β-catenin to accumulate and localize to the nucleus and subsequently induce a cellular response via gene transduction alongside the TCF/LEF (T-cell factor/lymphoid enhancing factor) [ 25 ] transcription factors. [ 24 ] β-catenin recruits other transcriptional coactivators, such as BCL9 , Pygopus [ 26 ] and Parafibromin/Hyrax. [ 27 ] The complexity of the transcriptional complex assembled by β-catenin is beginning to emerge thanks to new high-throughput proteomics studies. [ 28 ] However, a unified theory of how β‐catenin drives target gene expression is still missing, and tissue-specific players might assist β‐catenin to define its target genes. [ 29 ] The extensivity of the β-catenin interacting proteins complicates our understanding: β-catenin may be directly phosphorylated at Ser552 by Akt, which causes its disassociation from cell-cell contacts and accumulation in cytosol, thereafter 14-3-3ζ interacts with β-catenin (pSer552) and enhances its nuclear translocation. [ 30 ] BCL9 and Pygopus have been reported, in fact, to possess several β-catenin -independent functions (therefore, likely, Wnt signaling-independent). [ 31 ] [ 32 ] [ 33 ] The noncanonical planar cell polarity (PCP) pathway does not involve β-catenin. It does not use LRP-5/6 as its co-receptor and is thought to use NRH1 , Ryk , PTK7 or ROR2 . The PCP pathway is activated via the binding of Wnt to Fz and its co-receptor. The receptor then recruits Dsh , which uses its PDZ and DIX domains to form a complex with Dishevelled-associated activator of morphogenesis 1 ( DAAM1 ). Daam1 then activates the small G-protein Rho through a guanine exchange factor. Rho activates Rho-associated kinase (ROCK), which is one of the major regulators of the cytoskeleton . Dsh also forms a complex with rac1 and mediates profilin binding to actin . Rac1 activates JNK and can also lead to actin polymerization . Profilin binding to actin can result in restructuring of the cytoskeleton and gastrulation . [ 7 ] [ 34 ] The noncanonical Wnt/calcium pathway also does not involve β-catenin . Its role is to help regulate calcium release from the endoplasmic reticulum (ER) in order to control intracellular calcium levels. Like other Wnt pathways, upon ligand binding, the activated Fz receptor directly interacts with Dsh and activates specific Dsh-protein domains. The domains involved in Wnt/calcium signaling are the PDZ and DEP domains. [ 7 ] However, unlike other Wnt pathways, the Fz receptor directly interfaces with a trimeric G-protein. This co-stimulation of Dsh and the G-protein can lead to the activation of either PLC or cGMP-specific PDE . If PLC is activated, the plasma membrane component PIP2 is cleaved into DAG and IP3 . When IP3 binds its receptor on the ER, calcium is released. Increased concentrations of calcium and DAG can activate Cdc42 through PKC . Cdc42 is an important regulator of ventral patterning. Increased calcium also activates calcineurin and CaMKII . CaMKII induces activation of the transcription factor NFAT , which regulates cell adhesion, migration and tissue separation. [ 7 ] Calcineurin activates TAK1 and NLK kinase, which can interfere with TCF/β-Catenin signaling in the canonical Wnt pathway. [ 35 ] However, if PDE is activated, calcium release from the ER is inhibited. PDE mediates this through the inhibition of PKG, which subsequently causes the inhibition of calcium release. [ 7 ] The binary distinction of canonical and non-canonical Wnt signaling pathways has come under scrutiny and an integrated, convergent Wnt pathway has been proposed. [ 36 ] Some evidence for this was found for one Wnt ligand (Wnt5A). [ 37 ] Evidence for a convergent Wnt signaling pathway that shows integrated activation of Wnt/Ca2+ and Wnt/ β-catenin signaling, for multiple Wnt ligands, was described in mammalian cell lines. [ 38 ] Wnt signaling also regulates a number of other signaling pathways that have not been as extensively elucidated. One such pathway includes the interaction between Wnt and GSK3 . During cell growth, Wnt can inhibit GSK3 in order to activate mTOR in the absence of β-catenin. However, Wnt can also serve as a negative regulator of mTOR via activation of the tumor suppressor TSC2 , which is upregulated via Dsh and GSK3 interaction. [ 39 ] During myogenesis , Wnt uses PA and CREB to activate MyoD and Myf5 genes. [ 40 ] Wnt also acts in conjunction with Ryk and Src to allow for regulation of neuron repulsion during axonal guidance . Wnt regulates gastrulation when CK1 serves as an inhibitor of Rap1-ATPase in order to modulate the cytoskeleton during gastrulation. Further regulation of gastrulation is achieved when Wnt uses ROR2 along with the CDC42 and JNK pathway to regulate the expression of PAPC . Dsh can also interact with aPKC, Pa3 , Par6 and LGl in order to control cell polarity and microtubule cytoskeleton development. While these pathways overlap with components associated with PCP and Wnt/Calcium signaling, they are considered distinct pathways because they produce different responses. [ 7 ] In order to ensure proper functioning, Wnt signaling is constantly regulated at several points along its signaling pathways. [ 41 ] For example, Wnt proteins are palmitoylated . The protein porcupine mediates this process, which means that it helps regulate when the Wnt ligand is secreted by determining when it is fully formed. Secretion is further controlled with proteins such as GPR177 (wntless) and evenness interrupted and complexes such as the retromer complex. [ 7 ] [ 24 ] Upon secretion , the ligand can be prevented from reaching its receptor through the binding of proteins such as the stabilizers Dally and glypican 3 (GPC3), which inhibit diffusion. In cancer cells, both the heparan sulfate chains [ 42 ] [ 43 ] and the core protein [ 44 ] [ 45 ] of GPC3 are involved in regulating Wnt binding and activation for cell proliferation. [ 46 ] [ 47 ] Wnt recognizes a heparan sulfate structure on GPC3, which contains IdoA2S and GlcNS6S, and the 3-O-sulfation in GlcNS6S3S enhances the binding of Wnt to the heparan sulfate glypican. [ 48 ] A cysteine-rich domain at the N-lobe of GPC3 has been identified to form a Wnt-binding hydrophobic groove including phenylalanine-41 that interacts with Wnt. [ 45 ] [ 49 ] Blocking the Wnt binding domain using a nanobody called HN3 can inhibit Wnt activation. [ 45 ] At the Fz receptor, the binding of proteins other than Wnt can antagonize signaling. Specific antagonists include Dickkopf (Dkk), Wnt inhibitory factor 1 (WIF-1), [ 50 ] [ 51 ] secreted Frizzled-related proteins (SFRP), Cerberus , Frzb , Wise , SOST , and Naked cuticle . These constitute inhibitors of Wnt signaling. However, other molecules also act as activators. Norrin and R-Spondin2 activate Wnt signaling in the absence of Wnt ligand. Interactions between Wnt signaling pathways also regulate Wnt signaling. As previously mentioned, the Wnt/calcium pathway can inhibit TCF/β-catenin, preventing canonical Wnt pathway signaling. [ 7 ] [ 24 ] Prostaglandin E2 (PGE2) is an essential activator of the canonical Wnt signaling pathway. Interaction of PGE2 with its receptors E2/E4 stabilizes β-catenin through cAMP/PKA mediated phosphorylation. The synthesis of PGE2 is necessary for Wnt signaling mediated processes such as tissue regeneration and control of stem cell population in zebrafish and mouse. [ 5 ] Intriguingly, the unstructured regions of several oversized intrinsically disordered proteins play crucial roles in regulating Wnt signaling. [ 52 ] Wnt signaling plays a critical role in embryonic development. It operates in both vertebrates and invertebrates , including humans, frogs, zebrafish, C. elegans , Drosophila and others. It was first found in the segment polarity of Drosophila, where it helps to establish anterior and posterior polarities. It is implicated in other developmental processes . As its function in Drosophila suggests, it plays a key role in body axis formation, particularly the formation of the anteroposterior and dorsoventral axes. It is involved in the induction of cell differentiation to prompt formation of important organs such as lungs and ovaries . Wnt further ensures the development of these tissues through proper regulation of cell proliferation and migration . Wnt signaling functions can be divided into axis patterning, cell fate specification, cell proliferation and cell migration. [ 53 ] In early embryo development, the formation of the primary body axes is a crucial step in establishing the organism's overall body plan. The axes include the anteroposterior axis, dorsoventral axis, and right-left axis. Wnt signaling is implicated in the formation of the anteroposterior and dorsoventral (DV) axes. Wnt signaling activity in anterior-posterior development can be seen in mammals, fish and frogs. In mammals, the primitive streak and other surrounding tissues produce the morphogenic compounds Wnts, BMPs , FGFs , Nodal and retinoic acid to establish the posterior region during late gastrula . These proteins form concentration gradients. Areas of highest concentration establish the posterior region while areas of lowest concentration indicate the anterior region. In fish and frogs, β-catenin produced by canonical Wnt signaling causes the formation of organizing centers, which, alongside BMPs, elicit posterior formation. Wnt involvement in DV axis formation can be seen in the activity of the formation of the Spemann organizer , which establishes the dorsal region. Canonical Wnt signaling β-catenin production induces the formation of this organizer via the activation of the genes twin and siamois. [ 36 ] [ 53 ] Similarly, in avian gastrulation, cells of the Koller's sickle express different mesodermal marker genes that allow for the differential movement of cells during the formation of the primitive streak. Wnt signaling activated by FGFs is responsible for this movement. [ 54 ] [ 55 ] Wnt signaling is also involved in the axis formation of specific body parts and organ systems later in development. In vertebrates, sonic hedgehog (Shh) and Wnt morphogenetic signaling gradients establish the dorsoventral axis of the central nervous system during neural tube axial patterning. High Wnt signaling establishes the dorsal region while high Shh signaling indicates the ventral region. [ 56 ] Wnt is involved in the DV formation of the central nervous system through its involvement in axon guidance . Wnt proteins guide the axons of the spinal cord in an anterior-posterior direction. [ 57 ] Wnt is also involved in the formation of the limb DV axis. Specifically, Wnt7a helps produce the dorsal patterning of the developing limb. [ 36 ] [ 53 ] In the embryonic differentiation waves model of development Wnt plays a critical role as part a signalling complex in competent cells ready to differentiate. Wnt reacts to the activity of the cytoskeleton, stabilizing the initial change created by a passing wave of contraction or expansion and simultaneously signals the nucleus through the use of its different signalling pathways as to which wave the individual cell has participated in. Wnt activity thereby amplifies mechanical signalling that occurs during development. [ 58 ] [ 59 ] Cell fate specification or cell differentiation is a process where undifferentiated cells can become a more specialized cell type. Wnt signaling induces differentiation of pluripotent stem cells into mesoderm and endoderm progenitor cells . [ 60 ] These progenitor cells further differentiate into cell types such as endothelial, cardiac and vascular smooth muscle lineages. [ 61 ] Wnt signaling induces blood formation from stem cells. Specifically, Wnt3 leads to mesoderm committed cells with hematopoietic potential. [ 62 ] Wnt1 antagonizes neural differentiation and is a major factor in self-renewal of neural stem cells. This allows for regeneration of nervous system cells, which is further evidence of a role in promoting neural stem cell proliferation. [ 60 ] Wnt signaling is involved in germ cell determination, gut tissue specification, hair follicle development, lung tissue development, trunk neural crest cell differentiation, nephron development, ovary development and sex determination . [ 53 ] Wnt signaling also antagonizes heart formation, and Wnt inhibition was shown to be a critical inducer of heart tissue during development, [ 63 ] [ 64 ] [ 65 ] and small molecule Wnt inhibitors are routinely used to produce cardiomyocytes from pluripotent stem cells. [ 66 ] [ 67 ] In order to have the mass differentiation of cells needed to form the specified cell tissues of different organisms, proliferation and growth of embryonic stem cells must take place. This process is mediated through canonical Wnt signaling, which increases nuclear and cytoplasmic β-catenin. Increased β-catenin can initiate transcriptional activation of proteins such as cyclin D1 and c-myc , which control the G1 to S phase transition in the cell cycle . Entry into the S phase causes DNA replication and ultimately mitosis , which are responsible for cell proliferation. [ 68 ] This proliferation increase is directly paired with cell differentiation because as the stem cells proliferate, they also differentiate. This allows for overall growth and development of specific tissue systems during embryonic development. This is apparent in systems such as the circulatory system where Wnt3a leads to proliferation and expansion of hematopoietic stem cells needed for red blood cell formation. [ 69 ] The biochemistry of cancer stem cells is subtly different from that of other tumor cells. These so-called Wnt-addicted cells hijack and depend on constant stimulation of the Wnt pathway to promote their uncontrolled growth, survival and migration. In cancer , Wnt signaling can become independent of regular stimuli, through mutations in downstream oncogenes and tumor suppressor genes that become permanently activated even though the normal receptor has not received a signal. β-catenin binds to transcription factors such as the protein TCF4 and in combination the molecules activate the necessary genes. LF3 strongly inhibits this binding in vitro, in cell lines and reduced tumor growth in mouse models. It prevented replication and reduced their ability to migrate, all without affecting healthy cells. No cancer stem cells remained after treatment. The discovery was the product of " rational drug design ", involving AlphaScreens and ELISA technologies. [ 70 ] Cell migration during embryonic development allows for the establishment of body axes, tissue formation, limb induction and several other processes. Wnt signaling helps mediate this process, particularly during convergent extension. Signaling from both the Wnt PCP pathway and canonical Wnt pathway is required for proper convergent extension during gastrulation. Convergent extension is further regulated by the Wnt/calcium pathway, which blocks convergent extension when activated. Wnt signaling also induces cell migration in later stages of development through the control of the migration behavior of neuroblasts , neural crest cells, myocytes , and tracheal cells. [ 71 ] Wnt signaling is involved in another key migration process known as the epithelial-mesenchymal transition (EMT). This process allows epithelial cells to transform into mesenchymal cells so that they are no longer held in place at the laminin . It involves cadherin down-regulation so that cells can detach from laminin and migrate. Wnt signaling is an inducer of EMT, particularly in mammary development. [ 72 ] Insulin is a peptide hormone involved in glucose homeostasis within certain organisms. Specifically, it leads to upregulation of glucose transporters in the cell membrane in order to increase glucose uptake from the bloodstream . This process is partially mediated by activation of Wnt/β-catenin signaling, which can increase a cell's insulin sensitivity. In particular, Wnt10b is a Wnt protein that increases this sensitivity in skeletal muscle cells. [ 73 ] Since its initial discovery, Wnt signaling has had an association with cancer . When Wnt1 was discovered, it was first identified as a proto- oncogene in a mouse model for breast cancer. The fact that Wnt1 is a homolog of Wg shows that it is involved in embryonic development, which often calls for rapid cell division and migration. Misregulation of these processes can lead to tumor development via excess cell proliferation. [ 3 ] Canonical Wnt pathway activity is involved in the development of benign and malignant breast tumors. The role of Wnt pathway in tumor chemoresistance has been also well documented, as well as its role in the maintenance of a distinct subpopulation of cancer-initiating cells. [ 74 ] Its presence is revealed by elevated levels of β-catenin in the nucleus and/or cytoplasm, which can be detected with immunohistochemical staining and Western blotting . Increased β-catenin expression is correlated with poor prognosis in breast cancer patients. This accumulation may be due to factors such as mutations in β-catenin , deficiencies in the β-catenin destruction complex, most frequently by mutations in structurally disordered regions of APC , overexpression of Wnt ligands, loss of inhibitors and/or decreased activity of regulatory pathways (such as the Wnt/calcium pathway). [ 52 ] [ 75 ] [ 76 ] Breast tumors can metastasize due to Wnt involvement in EMT. Research looking at metastasis of basal-like breast cancer to the lungs showed that repression of Wnt/β-catenin signaling can prevent EMT, which can inhibit metastasis. [ 77 ] Wnt signaling has been implicated in the development of other cancers as well as in desmoid fibromatosis . [ 78 ] Changes in CTNNB1 expression, which is the gene that encodes β-catenin, can be measured in breast, colorectal , melanoma , prostate , lung , and other cancers. Increased expression of Wnt ligand-proteins such as Wnt1, Wnt2 and Wnt7A were observed in the development of glioblastoma , oesophageal cancer and ovarian cancer respectively. Other proteins that cause multiple cancer types in the absence of proper functioning include ROR1, ROR2, SFRP4 , Wnt5A, WIF1 and those of the TCF/LEF family. [ 79 ] Wnt signaling is further implicated in the pathogenesis of bone metastasis from breast and prostate cancer with studies suggesting discrete on and off states. Wnt is down-regulated during the dormancy stage by autocrine DKK1 to avoid immune surveillance, [ 80 ] as well as during the dissemination stages by intracellular Dact1. [ 81 ] Meanwhile Wnt is activated during the early outgrowth phase by E-selectin . [ 82 ] The link between PGE2 and Wnt suggests that a chronic inflammation-related increase of PGE2 may lead to activation of the Wnt pathway in different tissues, resulting in carcinogenesis . [ 5 ] Diabetes mellitus type 2 is a common disease that causes reduced insulin secretion and increased insulin resistance in the periphery. It results in increased blood glucose levels, or hyperglycemia , which can be fatal if untreated. Since Wnt signaling is involved in insulin sensitivity, malfunctioning of its pathway could be involved. Overexpression of Wnt5b, for instance, may increase susceptibility due to its role in adipogenesis , since obesity and type II diabetes have high comorbidity . [ 83 ] Wnt signaling is a strong activator of mitochondrial biogenesis . This leads to increased production of reactive oxygen species (ROS) known to cause DNA and cellular damage. [ 84 ] This ROS-induced damage is significant because it can cause acute hepatic insulin resistance, or injury-induced insulin resistance. [ 85 ] Mutations in Wnt signaling-associated transcription factors, such as TCF7L2 , are linked to increased susceptibility. [ 86 ]	https://en.wikipedia.org/wiki/Wnt_signaling_pathway
Woese's dogma is a principle of evolutionary biology first put forth by biophysicist Carl Woese in 1977. It states that the evolution of ribosomal RNA was a necessary precursor to the evolution of modern life forms. [ 1 ] This led to the advancement of the phylogenetic tree of life consisting of three domains rather than the previously accepted two. [ 2 ] While the existence of Eukarya and Prokarya were already accepted, Woese was responsible for the distinction between Bacteria and Archaea . [ 3 ] Despite initial criticism and controversy surrounding his claims, Woese's three domain system, based on his work regarding the role of rRNA in the evolution of modern life, has become widely accepted. [ 4 ] Evidence for Woese's dogma is well established through comparisons of RNA homology . Modern research allows more liberal use of RNA sequencing , allowing for a better comparative analysis between distant RNA. When analyzing multiple strains of E. coli , Root-Bernstein et al. have compared tRNA encodings found within rRNA with tRNA found in E. coli to see if the secondary structure was the same as more “modern” tRNA present in E. coli . [ 5 ] Comparisons between the tRNA encodings found in the rRNAs and mRNAs of the control sequences found that “sortings” for these sequences were extremely similar, and comparisons of translated protein structure indicated that homology was likely. [ 5 ] Additionally, sequences homologous to all tRNAs necessary for translation were present in 16s and 23s rRNAs, and synthetases to load these tRNAs were also found, indicating that many of the functions of transcription and translation present in more modern life exist in rRNA, if vestigially. [ 5 ] When comparing homologies of rRNA structures, it is necessary to analyze substructures. This is because models that study RNA structure on the whole do not currently exist. [ 6 ] Generally, phylogenies of rRNA subunits are created to understand each component, and how they function and evolve. Through phylogenies created that depict rRNA structural elements that are present in all three domains of life, the oldest structural components can be determined through relative dating . [ 7 ] These phylogenies were used in a study by Harish et al., to show that a helical stem labeled h44 in small subunit rRNA can be described as the oldest structural component of rRNA, which holds particular significance, as this structure responsible for linking processes in the small subunit, which is responsible for decoding, with the large subunit, which is responsible for the formation of peptide bonds and the releasing of elongation factors. [ 7 ] This essentially shows that the functional origin of the ribosome, responsible for protein synthesis, is common in all modern life throughout each of the three domains. Evidence has also been obtained in studying eukaryotic organelles, such as the chloroplast. Zablen et al.’s phylogenetic analysis conducted electrophoresis on chloroplast ribosomal RNA, specifically on the 16S rRNA of Euglena gracilis . [ 8 ] In conducting this experiment, researchers compared the electrophoretic fingerprint of this RNA to other chloroplasts and prokarya. In comparing these results, it was found that generally, these chloroplasts show a close genomic relationship, while a more distant one is seen for algae, and subsequently prokaryotic organisms. [ 8 ] This experiment shows that the rRNA of distantly related organisms has a similar origin of that in eukaryotic organelles, supporting the idea that the evolution of rRNA was a necessary precursor of modern life. One of the reasons that Woese's Dogma holds significance is because of the potential that RNA was the first primordial self-replicating molecule (see: RNA World ), meaning it would be key in the progression of modern life. [ 9 ] In particular, it has been proposed that ribosomes exist as a missing link in prebiotic evolution, with rRNA being a vestige of an ancient genome. [ 5 ] Some evidence exists for the proposal that rRNA functioned in the past to encode proteins that are key to ribosome function. [ 10 ] One notable example is the fact that rRNA proteins are commonly known to bind with their own mRNA. [ 10 ] In addition, some ribosomal proteins not only regulate their own expression, but the expression of other proteins as well. [ 11 ] These are both indications of self-replication, and indicate the possibility that the mRNA that encodes ribosomal proteins evolved from rRNA. [ 10 ] RNA existing as a primordial self replicating entity is an idea that faces criticism. The idea of rRNA in particular being sufficient on its own to explain the progression of modern life struggles due to the fact that it lacks certain key pieces of evidence. In particular RNA cannot be shown to be prebiotic, as there is no way for the nucleotides or nucleosides that compose it to be non-enzymatically replicated. [ 12 ] Additionally, other criticisms exist, such as the fact that RNA is not stable enough to have arisen prebiotically, and that it is too complex to have arisen prebiotically. [ 13 ] This has led to the development of other hypotheses, such as 'proteins first', which states that proteins arose prior to RNA, or coevolved with RNA. [ 13 ] This has also led to the proposal of other primordial molecules that may have developed into RNA and DNA, such as peptide nucleic acids , which also show evidence of self replication. [ 14 ] Despite the fact that criticisms might exist on the primordial or prebiotic nature of rRNA, these criticisms are not aimed at Woese's Dogma on the whole, as Woese's Dogma only claims that the evolution of rRNA was a necessary precursor to modern life, not that rRNA arose prebiotically. [ 1 ]	https://en.wikipedia.org/wiki/Woese's_dogma
The Woeseian revolution was the progression of the phylogenetic tree of life concept from two main divisions, known as the Prokarya and Eukarya , into three domains now classified as Bacteria , Archaea , and Eukaryotes. The discovery of the new domain stemmed from the work of biophysicist Carl Woese in 1977 from a principle of evolutionary biology designated as Woese's dogma . It states that the evolution of ribosomal RNA (rRNA) was a necessary precursor to the evolution of modern life forms. [ 1 ] Although the three-domain system has been widely accepted, the initial introduction of Woese’s discovery received criticism from the scientific community. The basis of phylogenetics was limited by the technology of the time, which led to a greater dependence on phenotypic classification before advances that would allow for molecular organization methods. This was a major reason why the dichotomy of all living things, being either animal or plant in nature, was deemed an acceptable theory. [ 2 ] Without truly understanding the genetic implication of each organismal classification in phylogenies via nucleic acid sequencing of shared molecular material, the phylogenetic tree of life and other such phylogenies would no doubt be incorrect. Woese’s advances in molecular sequencing and phylogenetic organization allowed for a better understanding of the three domains of life - the Bacteria, Archaea, and Eukaryotes. Regarding their varying types of shared rRNA, the small subunit rRNA was deemed as the best molecule to sequence to distinguish phylogenetic relationships because of its relatively small size, ease of isolation, and universal distribution. [ 3 ] This reorganization caused an initial pushback: it wasn't accepted until nearly a decade after its publication. [ 4 ] Possible factors that led to initial criticisms of his discovery included Woese's oligonucleotide cataloging, of which he was one of "only two or three people in the world" to be able to execute this method, let alone read the films. Further, Woese's background was in physics, whereas most of the research was being done in microbiology. [ 5 ]	https://en.wikipedia.org/wiki/Woeseian_revolution
The Wohl degradation in carbohydrate chemistry is a chain contraction method for aldoses . [ 1 ] The classic example is the conversion of glucose to arabinose as shown below. The reaction is named after the German chemist Alfred Wohl (1863–1939). Let's say we have a kiliani-fischer synthesis, it basically removes the row of the C2 carbon, it shortens the carbon chain by one carbon. In one modification, [ 2 ] [ 3 ] d-glucose is converted to the glucose oxime by reaction with hydroxylamine and sodium methoxide . In the second step the pentaacetyl glycononitrile is formed by reaction with acetic anhydride in acetic acid with sodium acetate . In this reaction step the oxime is converted into the nitrile with simultaneous conversion of all the alcohol groups to acetate groups. In the final step sodium methoxide in methanol is added, leading to removal of all the acetate groups and ejection of the nitrile group and collapse of the second carbon from a tetrahedral structure to an aldehyde. In a variation, the Ruff–Fenton degradation ( Otto Ruff 1898, H.J.H. Fenton 1893) converts the aldose first to the alpha-hydroxy-carboxylic acid with bromine and calcium hydroxide and then to the shortened aldose by reaction with Iron(III) sulfate and hydrogen peroxide . [ 4 ]	https://en.wikipedia.org/wiki/Wohl_degradation
Wohl model may refer to:	https://en.wikipedia.org/wiki/Wohl_model
The Wohlwill process is an industrial-scale chemical procedure used to refine gold to the highest degree of purity (99.999%). [ 1 ] The process was invented in 1874 by Emil Wohlwill . This electrochemical process involves using a cast gold ingot , often called a doré bar , of 95%+ gold to serve as an anode . Lower percentages of gold in the anode will interfere with the reaction, especially when the contaminating metal is silver or one of the platinum group elements. The cathodes for this reaction are small sheets of pure (24k) gold sheeting or stainless steel. Current is applied to the system, and electricity travels through the electrolyte of chloroauric acid . Gold and other metals are dissolved at the anode, and pure gold (coming through the chloroauric acid by ion transfer) is preferably plated onto the gold cathode while other metals remain in the solution. When the anode is dissolved, the cathode is removed and melted or otherwise processed in the manner required for sale or use. The resulting gold is 99.999% pure, and of higher purity than gold produced by the other common refining method, the Miller process , which produces gold of 99.5% purity. [ 1 ] [ 2 ] [ 3 ] For industrial gold production the Wohlwill process is necessary for highest purity gold applications. When lower purity gold is required, refiners often utilize the Miller process for its relative ease and quicker turnaround times and because it does not require a large inventory of gold, in the form of chloroauric acid. [ 2 ] [ 3 ]	https://en.wikipedia.org/wiki/Wohlwill_process
The Wohl–Aue reaction is an organic reaction between an aromatic nitro compound and an aniline to form a phenazine in presence of an alkali base . [ 1 ] [ 2 ] An example is the reaction between nitrobenzene and aniline : The reaction is named after Alfred Wohl and W. Aue.	https://en.wikipedia.org/wiki/Wohl–Aue_reaction
The Wohl–Ziegler reaction [ 1 ] [ 2 ] is a chemical reaction that involves the allylic or benzylic bromination of hydrocarbons using an N -bromosuccinimide and a radical initiator . [ 3 ] Best yields are achieved with N -bromosuccinimide in carbon tetrachloride solvent. Several reviews have been published. [ 4 ] [ 5 ] In a typical setup, a stoichiometric amount of N -bromosuccinimide solution and a small quantity of initiator are added to a solution of the substrate in CCl 4 , and the reaction mixture is stirred and heated to the boiling point. Initiation of the reaction is indicated by more vigorous boiling; sometimes the heat source may need to be removed. Once all N -bromosuccinimide (which is denser than the solvent) has been converted to succinimide (which floats on top) the reaction has finished. Due to the high toxicity and ozone-depleting nature of carbon tetrachloride, trifluorotoluene has been proposed as an alternative solvent suitable for the Wohl–Ziegler bromination. [ 6 ] The corresponding chlorination reaction cannot generally be achieved with N- chlorosuccinimide, [ 7 ] although more specialized reagents have been developed, [ 8 ] and the reaction can be achieved industrially with chlorine gas. [ 9 ] The mechanism by which the Wohl–Ziegler reaction proceeds was proposed by Paul Goldfinger in 1953, and his reaction mechanism is one of two proposed pathways through which aliphatic, allylic, and benzylic bromination with N -bromosuccinimide (NBS) occurs. [ 10 ] It has been shown that the Goldfinger mechanism is the proper mechanism as opposed to the previously accepted mechanism proposed by George Bloomfield, which, though consistent during selectivity studies, turned out to be overly simplistic. [ 10 ] The generation of NBS radicals depicted in the Bloomfield mechanism has been shown to be far more difficult than imagined when it was proposed, which is why it has failed as a proper model throughout the years; however, evidence suggests that the Bloomfield mechanism is still acceptable for the oxidation of alcohols using NBS. [ 10 ] In the Goldfinger mechanism, the purpose of the NBS is simply to maintain a very low concentration of molecular bromine, while in the Bloomfield mechanism, its purpose is the generation of the initial radical used in the reaction, [ 11 ] which again can be quite a difficult process. [ 12 ] This is because it requires a special consideration for the behavior of the NBS radical; the only way it can possibly function as proposed in Bloomfield's mechanism is if the dissociation energy for the N-Br bond in NBS is smaller than that for Br 2 , and much evidence has been seen to suggest contrary behavior. [ 12 ] [ 13 ] Goldfinger's proposed mechanism does not require any special considerations, as all radical species are behaving normally, and it is partly because of this that his mechanism is regarded as correct. [ 12 ] To further explore the accepted reaction mechanism, it must be understood that there are competing radical pathways in any radical reaction; it is the same in this case, as addition and substitution pathways are competing. [ 14 ] Achieving the desired brominated product requires that the substitution pathway be dominant, and reaction conditions can indeed be manipulated to promote this pathway over the less desirable addition pathway. [ 13 ] Displayed below are the two pathways in their entirety; there are side reactions included in this figure for the sake of completeness, such as steps 6 and 8; these pathways are general for almost all radical reactions, so NBS is not pictured here, but its role will be discussed below.	https://en.wikipedia.org/wiki/Wohl–Ziegler_bromination
Wojciech Szpankowski (born February 18, 1952, in Wapno ) is the Saul Rosen Professor of Computer Science at Purdue University . [ 3 ] He is known for his work in analytic combinatorics , analysis of algorithms and analytic information theory . He is the director of the NSF Science and Technology Center for Science of Information. [ 4 ] Szpankowski received his MS and PhD in Electrical Engineering and Computer Science from the Technical University of Gdańsk in 1970 and 1980 respectively. [ 5 ]	https://en.wikipedia.org/wiki/Wojciech_Szpankowski
In statistics , Wold's decomposition or the Wold representation theorem (not to be confused with the Wold theorem that is the discrete-time analog of the Wiener–Khinchin theorem ), named after Herman Wold , says that every covariance-stationary time series Y t {\displaystyle Y_{t}} can be written as the sum of two time series, one deterministic and one stochastic . Formally where: The moving average coefficients have these properties: This theorem can be considered as an existence theorem: any stationary process has this seemingly special representation. Not only is the existence of such a simple linear and exact representation remarkable, but even more so is the special nature of the moving average model. Imagine creating a process that is a moving average but not satisfying these properties 1–4. For example, the coefficients b j {\displaystyle b_{j}} could define an acausal and non-minimum delay [ clarification needed ] model. Nevertheless the theorem assures the existence of a causal minimum delay moving average [ clarification needed ] that exactly represents this process. How this all works for the case of causality and the minimum delay property is discussed in Scargle (1981), where an extension of the Wold decomposition is discussed. The usefulness of the Wold Theorem is that it allows the dynamic evolution of a variable Y t {\displaystyle Y_{t}} to be approximated by a linear model . If the innovations ε t {\displaystyle \varepsilon _{t}} are independent , then the linear model is the only possible representation relating the observed value of Y t {\displaystyle Y_{t}} to its past evolution. However, when ε t {\displaystyle \varepsilon _{t}} is merely an uncorrelated but not independent sequence, then the linear model exists but it is not the only representation of the dynamic dependence of the series. In this latter case, it is possible that the linear model may not be very useful, and there would be a nonlinear model relating the observed value of Y t {\displaystyle Y_{t}} to its past evolution. However, in practical time series analysis , it is often the case that only linear predictors are considered, partly on the grounds of simplicity, in which case the Wold decomposition is directly relevant. The Wold representation depends on an infinite number of parameters, although in practice they usually decay rapidly. The autoregressive model is an alternative that may have only a few coefficients if the corresponding moving average has many. These two models can be combined into an autoregressive-moving average (ARMA) model , or an autoregressive-integrated-moving average (ARIMA) model if non-stationarity is involved. See Scargle (1981) and references there; in addition this paper gives an extension of the Wold Theorem that allows more generality for the moving average (not necessarily stable, causal, or minimum delay) accompanied by a sharper characterization of the innovation (identically and independently distributed, not just uncorrelated). This extension allows the possibility of models that are more faithful to physical or astrophysical processes, and in particular can sense ″the arrow of time .″	https://en.wikipedia.org/wiki/Wold's_theorem
Woldemar Anatol Weyl (1901 – July 30, 1975) was a German-born scientist. Weyl taught at the Kaiser Wilhelm Institute between 1932 and 1936, when he began traveling to the United States as a visiting professor at Pennsylvania State University . [ 1 ] Due to the increasing influence of the Nazi Party , Weyl choose not to return to Germany and was offered full tenure at PSU in 1938. [ 1 ] [ 2 ] In 1960, Weyl and mathematician Haskell Curry were appointed to the first two Evan Pugh Professorships at Penn State. [ 3 ] Weyl died in State College, Pennsylvania on July 30, 1975, aged 74. [ 1 ] This article about a German scientist is a stub . You can help Wikipedia by expanding it . This article about an American scientist is a stub . You can help Wikipedia by expanding it .	https://en.wikipedia.org/wiki/Woldemar_Weyl
Wolf distribution is the species distribution of the wolf ( Canis lupus ). Originally, wolves occurred in Eurasia above the 12th parallel north and in North America above the 15th parallel north . However, deliberate human persecution has reduced the species' range to about one-third, because of livestock predation and fear of wolf attacks on humans. The species is now extirpated in much of Western Europe , Mexico , and the contiguous United States , and completely from the British Isles and the Japanese archipelago . In modern history , the gray wolf occurs mostly in wilderness and remote areas, particularly in Canada , Alaska , the Northern United States , Europe and Asia from about the 75th parallel north to the 12th parallel north. Wolf population declines have been arrested since the 1970s, and have fostered recolonization and reintroduction in parts of its former range, due to legal protection, changes in land-use and rural human population shifts to cities. Competition with humans for livestock and game species, concerns over the danger posed by wolves to people, and habitat fragmentation pose a continued threat to the species. Despite these threats, because of the gray wolf's relatively widespread range and stable population, it is classified as Least Concern on the IUCN Red List . [ 1 ] In Africa the population of wolves is limited to the northern regions with the African golden wolf ( Canis lupaster ) north of the Sahara and the Ethiopian wolf ( Canis simensis ) in Ethiopia. Wolf populations strongly declined across Europe during the 18th and 19th centuries largely due to human persecution, and by the End of World War II in Europe they had been extirpated from all of Central Europe and almost all of Northern Europe . [ 2 ] The extirpation of Northern Europe's wolves first became an organized effort during the Middle Ages , and continued until the late 19th century. In England , wolf eradication was enforced by legislation , and the last wolf was killed in the early 16th century during the reign of Henry VII (reigned 1485–1509). Wolves lasted longer in Scotland , where they sheltered in vast tracts of forest, which were subsequently burned down. Wolves managed to survive in the forests of Braemar and Sutherland until 1684. The extirpation of wolves in Ireland followed a similar course, with the last wolf believed to have been killed in 1786. [ 3 ] A wolf bounty was introduced in Sweden in 1647, after the extirpation of moose and reindeer forced wolves to feed on livestock. The Sami extirpated wolves in northern Sweden in organized drives. By 1960, few wolves remained in Sweden, because of the use of snowmobiles in hunting them, with the last specimen being killed in 1966. The gray wolf was extirpated in Denmark in 1772 and Norway's last wolf was killed in 1973. The species was decimated in 20th century Finland, despite regular dispersals from Russia. The gray wolf was only present in the eastern and northern parts of Finland by 1900, though its numbers increased after World War II . [ 4 ] In Central Europe , wolves were dramatically reduced in number during the early 19th century, because of organized hunts and reductions in ungulate populations. In Bavaria , the last wolf was killed in 1847, and had disappeared from the Rhine regions by 1899. [ 4 ] In Switzerland , wolves were extirpated in the 20th century; they are naturally coming back from Italy since the 1990s. [ 5 ] In 1934, Nazi Germany became the first state in modern history to place the wolf under protection, though the species was already extirpated in Germany at this point. [ 6 ] The last free-living wolf to be killed on the soil of present-day Germany before 1945 was the so-called " Tiger of Sabrodt ", which was shot near Hoyerswerda , Lusatia (then Lower Silesia ) in 1904. Today, wolves have returned to the area. [ 7 ] Wolf hunting in France was first institutionalized by Charlemagne between 800 and 813, when he established the louveterie , a special corps of wolf hunters. The louveterie was abolished after the French Revolution in 1789, but was reestablished in 1814. In 1883, up to 1,386 wolves were killed, with many more by poison. [ 4 ] In Eastern Europe , some wolves remained because of the area's contiguity with Asia and its large forested areas. However, Eastern European wolf populations were reduced to very low numbers by the late 19th century. Wolves were extirpated in Slovakia during the first decade of the 20th century and, by the mid-20th century, could only be found in a few forested areas in eastern Poland. Wolves in the eastern Balkans benefitted from the region's contiguity with the former Soviet Union and large areas of plains, mountains and farmlands. Wolves in Hungary occurred in only half the country around the start of the 20th century, and were largely restricted to the Carpathian Basin . Wolf populations in Romania remained largely substantial, with an average of 2,800 wolves being killed annually out of a population of 4,600 from 1955 to 1965. An all-time low was reached in 1967, when the population was reduced to 1,550 animals. The extirpation of wolves in Bulgaria was relatively recent, as a previous population of about 1,000 animals in 1955 was reduced to about 100–200 in 1964. In Greece, the species disappeared from the southern Peloponnese in 1930. Despite periods of intense hunting during the 18th century, wolves never disappeared in the western Balkans, from Albania to the former Yugoslavia . Organized persecution of wolves began in Yugoslavia in 1923, with the setting up of the Wolf Extermination Committee (WEC) in Kočevje , Slovenia . The WEC was successful in reducing wolf numbers in the Dinaric Alps . [ 4 ] In Southern Europe , some wolves remained because of greater cultural tolerance of the species. [ citation needed ] Wolf populations only began declining in the Iberian Peninsula in the early 19th century, and was reduced by a half of its original size by 1900. Wolf bounties were regularly paid in Italy as late as 1950. Wolves were extirpated in the Alps by 1800, and numbered only 100 by 1973, inhabiting only 3–5% of their former Italian range. [ 4 ] The recovery of European wolf populations began after the 1950s, when traditional pastoral and rural economies declined and thus removed the need to heavily persecute wolves. By the 1980s, small and isolated wolf populations expanded in the wake of decreased human density in rural areas and the recovery of wild prey populations. [ 8 ] The gray wolf has been fully protected in Italy since 1976, and now holds a population of over 1,269–1,800. [ 9 ] Italian wolves entered France's Mercantour National Park in 1993, and at least fifty wolves were discovered in the western Alps in 2000. By 2013 the 250 wolves in the Western Alps imposed a significant burden on traditional sheep and goat husbandry with a loss of over 5,000 animals in 2012. [ 10 ] There are approximately 2,000 wolves inhabiting the Iberian Peninsula , of which 150 reside in northeastern Portugal . In Spain , the species occurs in Galicia , Leon , and Asturias . Although hundreds of Iberian wolves are illegally killed annually, the population has expanded south across the river Duero and east to the Asturias and Pyrenees Mountains . [ 8 ] In 1978, wolves began recolonising central Sweden after a 12-year absence, and have since expanded into southern Norway. As of 2020, the total number of Swedish and Norwegian wolves is estimated to be 450. [ 11 ] The gray wolf is protected in Sweden but with a 12% annual rate of poaching , [ 12 ] and partially controlled in Norway. The Scandinavian wolf populations owe their continued existence to neighbouring Finland's contiguity with the Republic of Karelia , which houses a large population of wolves. Wolves in Finland are protected only in the southern third of the country, and can be hunted in other areas during specific seasons, [ 8 ] though poaching remains common, with 90% of young wolf deaths being due to human predation, and the number of wolves killed exceeds the number of hunting licenses, in some areas by a factor of two. Furthermore, the decline in the moose populations has reduced the wolf's food supply. [ 13 ] [ 14 ] Since 2011, the Netherlands, Belgium and Denmark have also reported wolf sightings presumably by natural migration from adjacent countries. [ 15 ] [ 16 ] In 2016, a female wolf tracked 550 kilometers from a region southwest of Berlin to settle in Jutland, Denmark where male wolves had been reported in 2012 for the first time in 200 years. [ 17 ] Wolves have also commenced breeding in Lower Austria's Waldviertel region for the first time in over 130 years. [ 18 ] Wolf populations in Poland have increased to about 800–900 individuals since being classified as a game species in 1976. Poland plays a fundamental role in providing routes of expansion into neighbouring Central European countries. In the east, its range overlaps with populations in Lithuania, Belarus , Ukraine , and Slovakia . A population in western Poland expanded into eastern Germany and in 2000 the first pups were born on German territory. [ 19 ] In 2012, an estimated 14 wolf packs were living in Germany (mostly in the east and north) and a pack with pups has been sighted within 15 miles of Berlin ; [ 20 ] the number increased to 46 packs in 2016. [ 21 ] The gray wolf is protected in Slovakia, though an exception is made for wolves killing livestock. A few Slovakian wolves disperse into the Czech Republic, where they are afforded full protection. Wolves in Slovakia, Ukraine and Croatia may disperse into Hungary, where the lack of cover hinders the buildup of an autonomous population. Although wolves have special status in Hungary, they may be hunted with a year-round permit if they cause problems. [ 8 ] Romania has a large population of wolves, numbering 2,500 animals. The wolf has been a protected animal in Romania since 1996, although the law is not enforced. The number of wolves in Albania and North Macedonia is largely unknown, despite the importance the two countries have in linking wolf populations from Greece to those of Bosnia and Herzegovina and Croatia. Although protected, sometimes wolves are still illegally killed in Greece, and their future is uncertain. Wolf numbers have declined in Bosnia and Herzegovina since 1986, while the species is fully protected in neighbouring Croatia and Slovenia . [ 8 ] Although wolf-dog hybridization in Europe has raised concern among conservation groups fearing for the gray wolf's purity, genetic tests show that introgression of dog genes into European gray wolf populations does not pose a significant threat. Also, as wolf and dog mating seasons do not fully coincide, the likelihood of wild wolves and dogs mating and producing surviving offspring is small. [ 22 ] During the 19th century, gray wolves were widespread in many parts of the Holy Land east and west of the Jordan River . However, they decreased considerably in number between 1964 and 1980, largely because of persecution by farmers. [ 23 ] The species was not considered common in northern and central Saudi Arabia during the 19th century, with most early publications citing sources which involved animals either from southwestern Asir , northern rocky areas bordering Jordan , or areas surrounding Riyadh . [ 24 ] The gray wolf's range in the Soviet Union encompassed nearly the entire territory of the country, being absent only on the Solovetsky Islands , Franz-Josef Land , Severnaya Zemlya , and the Karagin , Commander and Shantar Islands . The species was extirpated twice in Crimea , once after the Russian Civil War , and again after World War II . [ 25 ] Following the two world wars the Soviet wolf populations peaked twice, with 30,000 wolves being harvested annually out of a population of 200,000 during the 1940s, and 40,000–50,000 harvested during peak years. Soviet wolf populations reached a low around 1970, disappearing over much of European Russia . The population increased again by 1980 to about 75,000, with 32,000 being killed in 1979. [ 26 ] Wolf populations in northern Inner Mongolia declined during the 1940s, primarily because of poaching of gazelles , the wolf's main prey. [ 27 ] In British-ruled India , wolves were heavily persecuted because of their attacks on sheep, goats and children. In 1876, 2,825 wolves were bountied in the North-Western Provinces (NWP) and Bihar . By the 1920s, wolf eradication remained a priority in the NWP and Awadh . Overall, over 100,000 wolves were killed for bounties in British India between 1871 and 1916. [ 28 ] Wolves in Japan were extirpated during the Meiji restoration period, in a campaign known as ōkami no kujo . The wolf was deemed a threat to ranching, which the Meiji government promoted at the time, and targeted via a bounty system and a direct chemical poisoning campaign inspired by the similar contemporary American campaign. The last Japanese wolf was a male killed on January 23, 1905 near Washikaguchi (now called Higashi Yoshiro). [ 29 ] The now-extirpated Japanese wolves were descended from large Siberian wolves, which colonized the Korean Peninsula and Japan, before it separated from mainland Asia, 20,000 years ago during the Pleistocene. During the Holocene , the Tsugaru Strait widened and isolated Honshu from Hokkaido , thus causing climatic changes leading to the extinction of most large-bodied ungulates inhabiting the archipelago. Japanese wolves likely underwent a process of island dwarfism 7,000–13,000 years ago in response to these climatological and ecological pressures. C. l. hattai (formerly native to Hokkaidō) was significantly larger than its southern cousin C. l. hodophilax , as it inhabited higher elevations and had access to larger prey, as well as a continuing genetic interaction with dispersing wolves from Siberia. [ 30 ] Gray wolves had a wide historic range in China encompassing nearly all of mainland China , including southern China. [ 31 ] A systematic review by Wang et al. in 2016, found museum specimens from wolves from across China, in 13 provinces, including several in southern China - two specimens sampled from two southern Chinese provinces ( Zhejiang and Fujian ) in 1974, and one from southern Yunnan in 1985. [ 31 ] This study also reviewed more than 100 articles and found modern, recent records of gray wolves in every continental province of China between 1964 and the present except for three provinces - Tianjin , Jiangsu , and Fujian . [ 31 ] Wolves were recorded in South China (in Yunnan province) as late as 2011, and in the two southernmost provinces ( Guangdong and Guangxi ) in the year of 2000. [ 31 ] From these findings, the researchers concluded that wolves are still present across all parts of continental China. [ 31 ] There is little reliable data on the status of wolves in the Middle East , save for those in Israel and Saudi Arabia , though their numbers appear to be stable, and are likely to remain so. Throughout the Middle East, the species is only protected in Israel. Israel has a stable population of 80-100 Indian wolves and 100-150 Arabian wolves , which are legally protected under the 1955 Wildlife Protection Law . [ 32 ] [ 33 ] [ 34 ] Elsewhere, it can be hunted year-round by Bedouins . Israel's conservation policies and effective law enforcement maintain a moderately sized wolf population, which radiates into neighbouring countries, while Saudi Arabia has vast tracts of desert, where about 300–600 wolves live undisturbed. [ 35 ] The wolf survives throughout most of its historical range in Saudi Arabia, probably because of a lack of pastoralism and abundant human waste. [ 24 ] Turkey may play an important role in maintaining wolves in the region, because of its contiguity with Central Asia. [ 35 ] Although Turkish wolves have no legal protection, they may number about 7,000 individuals. [ 36 ] The mountains of Turkey have served as a refuge for the few wolves remaining in Syria . A small wolf population occurs in the Golan Heights , and is well protected by the military activities there. Wolves living in the southern Negev desert are contiguous with populations living in the Egyptian Sinai and Jordan . [ 35 ] The northern regions of Afghanistan and Pakistan are important strongholds for the wolf. It has been estimated that there are about 300 wolves in approximately 60,000 km 2 (23,000 sq mi) of Jammu and Kashmir in northern India, and 50 more in Himachal Pradesh . Overall, India supports about 800–3,000 wolves, scattered among several remnant populations. Although protected since 1972, Indian wolves are classed as endangered, with many populations lingering in low numbers or living in areas increasingly used by humans. Little is known of current wolf populations in Iran, which occurred throughout the country in low densities during the mid-1970s. Although present in Nepal and Bhutan , there is no information on wolves occurring there. [ 26 ] Wolf populations throughout Northern and Central Asia are largely unknown, but are estimated in the hundreds of thousands based on annual harvests. Since the fall of the Soviet Union , continent-wide culling of wolves has ceased, and wolf populations have increased to about 25,000–30,000 animals throughout the former Soviet Union . In China and Mongolia , wolves are only protected in reserves. Mongolian populations have been estimated at 10,000–30,000, while the status of wolves in China is more fragmentary. The north has a declining population of an estimated 400 wolves, while Xinjiang and Tibet hold about 10,000 and 2,000 respectively. [ 37 ] In 2008, an authoritative reference stated that the gray wolf could be found across mainland China. [ 38 ] In 2017, a comprehensive study found that the gray wolf was present across all of mainland China, both in the past and today. It exists in southern China, which refutes claims made by some researchers in the Western world that the wolf had never existed in southern China. [ 39 ] [ 40 ] In 2019, a genomic study on the wolves of China included museum specimens of wolves from southern China that were collected between 1963 and 1988. The wolves in the study formed 3 clades: north Asian wolves that included those from northern China and eastern Russia, Himalayan wolves from the Tibetan Plateau, and a unique population from southern China. One specimen from Zhejiang province in eastern China shared gene flow with the wolves from southern China, however its genome was 12-14 percent admixed with a canid that may be the dhole or an unknown canid that predates the genetic divergence of the dhole. The wolf population from southern China is believed to be still existing in that region. [ 41 ] On Hainan Island, historical records of gray wolves exist until 1931, where they are estimated to have become extinct around 1941. [ 42 ] Originally, the gray wolf occupied all of North America north of about 20°N. It occurred all over the mainland, except for the southeastern United States and the tropical and subtropical areas of Mexico. Large continental islands occupied by wolves included Newfoundland , Vancouver Island , the southeastern Alaskan islands, and throughout the Arctic Archipelago and Greenland . [ 43 ] While Lohr and Ballard postulated that the gray wolf had never been present on Prince Edward Island , [ 44 ] [ 45 ] : 392 analysis of references to the island's native fauna in unpublished and published historical records has found that gray wolves were resident there at the time of the first French settlement in 1720. In his November 6, 1721 letter to the French Minister of the Marine, Louis Denys de La Ronde reported that the island was home to wolves "of a prodigious size", and sent a wolf pelt back to France to substantiate his claim. As the island was cleared for settlement, the gray wolf population may have been extirpated, or relocated to the mainland across the winter ice: the few subsequent wolf reports date from the mid-19th century and describe the creatures as transient visitors from across the Northumberland Strait . [ 45 ] : 386 The decline of North American wolf populations coincided with increasing human populations and the expansion of agriculture. In Canada, the gray wolf was extirpated in New Brunswick and Nova Scotia between 1870 and 1921, and in Newfoundland around 1911. It vanished from the southern regions of Quebec and Ontario between 1850 and 1900. The gray wolf's decline in the prairies began with the extirpation of the American bison and other ungulates in the 1860s–70s. From 1900 to 1930, the gray wolf was virtually eliminated from the western U.S. and adjoining parts of Canada, because of intensive predator control programs aimed at eradicating the species. By the start of the 20th century, the species had almost disappeared from the eastern U.S., excepting some areas of the Appalachians and the northwestern Great Lakes Region . The gray wolf was extirpated by federal and state governments from all of the U.S. by 1960, except in Alaska and northern Minnesota . The decline in North American wolf populations was reversed from the 1930s to the early 1950s, particularly in southwestern Canada, because of expanding ungulate populations resulting from improved regulation of big game hunting. This increase triggered a resumption of wolf control in western and northern Canada. Thousands of wolves were killed from the early 1950s to the early 1960s, mostly by poisoning. This campaign was halted and wolf populations increased again by the mid-1970s. [ 43 ] The gray wolf is found in approximately 80% of its historical range in Canada, thus making it an important stronghold for the species. [ 43 ] Canada is home to about 52,000–60,000 wolves, whose legal status varies according to province and territory . First Nations residents may hunt wolves without restriction, and some provinces require licenses for residents to hunt wolves while others do not. In Alberta , wolves on private land may be baited and hunted by the landowner without requiring a license, and in some areas, wolf hunting bounty programs exist. [ 46 ] [ 47 ] Large-scale wolf population control through poisoning, trapping and aerial hunting is also presently conducted by government-mandated programs in order to support populations of endangered prey species such as woodland caribou . [ 48 ] In Alaska, the gray wolf population is estimated at 6,000–7,000, and can be legally harvested during hunting and trapping seasons, with bag limits and other restrictions. In 1978, wolves were protected in the United States under the federal Endangered Species Act as it was determined that they were in danger of going extinct and needed protection to aid their recovery. [ 49 ] Canadian wolves began to naturally recolonize northern Montana around Glacier National Park in 1979, and the first wolf den in the western U.S. in over half a century was documented there in 1986. [ 50 ] The wolf population in northwest Montana initially grew as a result of natural reproduction and dispersal to about 48 wolves by the end of 1994. [ 51 ] From 1995 to 1996, wolves from Alberta and British Columbia were reintroduced into Yellowstone National Park and Idaho and expanded their range into the northern Rocky Mountains and Pacific Northwest . [ 49 ] Wolves began swimming the Snake River from Idaho to Oregon in the 1990s. The vast majority clustered in their historic range in the northeast corner of the state, where the forests are full of elk and deer. [ 52 ] In 2010, state biologists noticed wolves dispersing into the Cascade Range . [ 53 ] Washington state officials observed wolves from Idaho, Montana, Oregon, and British Columbia dispersing into eastern Washington and the North Cascades. [ 54 ] The California Department of Fish and Wildlife (CDFW) monitored the expansion of wolves in Oregon and began in 2011 to prepare for the possibility of wolves recolonizing the state. [ 55 ] [ 56 ] The repopulation of wolves in California was recognized in late December 2011, when OR-7 , a male wolf from Oregon , became the first confirmed wild wolf in California since 1924. The first resident wolf pack was confirmed in 2015. Additional wolves have been tracked entering the state, as the Cascade Range extends south from Oregon into northern California. Wolves are dispersing into the Sierra Nevada and other portions of their historic habitat. [ 57 ] Wolves from the Greater Yellowstone Ecosystem have dispersed into Colorado several times in the 21st century. In 2021, scientists documented the first litter of pups born to wolves in the state since the wolves' original extirpation. This resident wolf pack is monitored by Colorado Parks & Wildlife . In 2020, voters narrowly approved wolf reintroduction into the state. In December of 2023, ten wolves were released on public lands in Colorado's Summit and Grand Counties. [ 58 ] Occasionally, Eastern wolves ( Canis lycaon ) from Canada disperse into Upstate New York . This has been officially confirmed three times in the 21st century. The most recent wolf to enter New York was killed by a hunter who mistook it for a coyote. [ 59 ] The Western Great Lakes forests are inhabited by wolves which includes the provinces of Manitoba and Ontario along with the Midwestern states of Michigan , Minnesota , and Wisconsin which are estimated to have 4,400 wolves. Management under the Endangered Species Act allowed the wolves in Minnesota to flourish and repopulate northern Wisconsin and the Upper Peninsula of Michigan . Wolves were removed from federal protection in January 2021 with management authority remaining with state and tribal authorities. [ 49 ] This was reversed except in Idaho, Montana, Wyoming, and parts of nearby states by a court order on February 10, 2022. [ 60 ] [ 61 ] The Mexican wolf ( Canis lupus baileyi ) was reintroduced to Arizona , New Mexico , and the Sierra Madre Occidental in Mexico in 1998. Reintroduced Mexican wolves in Arizona and New Mexico are protected under the ESA and, as of late 2002, number 28 individuals in eight packs. [ 62 ] On March 9, 2022, two new breeding pairs of Mexican gray wolves were released into the wild in the state of Chihuahua in northern Mexico , bringing the total number of Mexican gray wolves in the country to around 45 wild individuals. [ 63 ] in March 2024, the Fish and Wildlife Services discovered that the wild population of Mexican gray wolves in the American Southwest had increased to 257 wolves, with 144 wolves (36 packs) in New Mexico and 113 wolves (20 packs) in Arizona. The annual pup survival rate was 62%. 113 wolves (44% of the population) have collars for monitoring and management. [ 64 ] In 1991, Kentucky's Land Between the Lakes partnered with the U.S. Fish and Wildlife Service for the Red Wolf Recovery Program, a captive breeding program. [ 65 ]	https://en.wikipedia.org/wiki/Wolf_distribution

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