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https://en.wikipedia.org/wiki/Information%20diving
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Information diving is the practice of recovering technical data, sometimes confidential or secret, from discarded material. In recent times, this has chiefly been from data storage elements in discarded computers, most notably recoverable data remaining on hard drives. Those in charge of discarding computers usually neglect to erase the hard drive. It is often in such circumstances for an information diver to copy installed software (e.g., word processors, operating systems, computer games, etc.). Other data may also be available, such as credit card information that was stored on the machine. Companies claim to be especially careful with customer data, but the number of data breaches by any type of entity (e.g., education, health care, insurance, government, ...) suggest otherwise. In the UK, information diving has been referred to as "binology."
Today, files, letters, memos, photographs, IDs, passwords, credit cards, and more can be found in dumpsters. Many people do not consider that sensitive information on items they discarded may be recovered. Such information, when recovered, is sometimes usable for fraudulent purposes (see also "identity theft" and physical information security). This method of dumpster diving is also sometimes used by attorneys or their agents when seeking to enforce court-ordered money judgments: the judgment debtor's trash may contain information about assets that can then be more-readily located for levying.
Supposedly, information diving was more common in the 1980s due to lax security; when businesses became aware of the need for increased security in the early 1990s, sensitive documents were shredded before being placed in dumpsters. There is still considerable Internet activity on the subject of dumpster diving, so it is unlikely to have stopped with the widespread introduction of document shredding. Security mythology has it that curious hackers or malicious crackers commonly use this technique.
Cases
Printed manuals
In earlie
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https://en.wikipedia.org/wiki/Volume%20boot%20record
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A volume boot record (VBR) (also known as a volume boot sector, a partition boot record or a partition boot sector) is a type of boot sector introduced by the IBM Personal Computer. It may be found on a partitioned data storage device, such as a hard disk, or an unpartitioned device, such as a floppy disk, and contains machine code for bootstrapping programs (usually, but not necessarily, operating systems) stored in other parts of the device. On non-partitioned storage devices, it is the first sector of the device. On partitioned devices, it is the first sector of an individual partition on the device, with the first sector of the entire device being a Master Boot Record (MBR) containing the partition table.
The code in volume boot records is invoked either directly by the machine's firmware or indirectly by code in the master boot record or a boot manager. Code in the MBR and VBR is in essence loaded the same way.
Invoking a VBR via a boot manager is known as chain loading. Some dual-boot systems, such as NTLDR (the boot loader for all releases of Microsoft's Windows NT-derived operating systems up to and including Windows XP and Windows Server 2003), take copies of the bootstrap code that individual operating systems install into a single partition's VBR and store them in disc files, loading the relevant VBR content from file after the boot loader has asked the user which operating system to bootstrap.
In Windows Vista, Windows Server 2008 and newer versions, NTLDR was replaced; the boot-loader functionality is instead provided by two new components: WINLOAD.EXE and the Windows Boot Manager.
In file systems such as FAT12 (except for in DOS 1.x), FAT16, FAT32, HPFS and NTFS, the VBR also contains a BIOS Parameter Block (BPB) that specifies the location and layout of the principal on-disk data structures for the file system. (A detailed discussion of the sector layout of FAT VBRs, the various FAT BPB versions and their entries can be found in the FAT article.)
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https://en.wikipedia.org/wiki/Incentive%20compatibility
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A mechanism is called incentive-compatible (IC) if every participant can achieve the best outcome to themselves just by acting according to their true preferences. For example, there is incentive compatibility if high-risk clients are better off in identifying themselves as high-risk to insurance firms, who only sell discounted insurance to high-risk clients. Likewise, they would be worse off if they pretend to be low-risk. Low-risk clients who pretend to be high-risk would also be worse off.
There are several different degrees of incentive-compatibility:
The stronger degree is dominant-strategy incentive-compatibility (DSIC). It means that truth-telling is a weakly-dominant strategy, i.e. you fare best or at least not worse by being truthful, regardless of what the others do. In a DSIC mechanism, strategic considerations cannot help any agent achieve better outcomes than the truth; hence, such mechanisms are also called strategyproof or truthful. (See Strategyproofness)
A weaker degree is Bayesian-Nash incentive-compatibility (BNIC). It means that there is a Bayesian Nash equilibrium in which all participants reveal their true preferences. I.e, if all the others act truthfully, then it is also best or at least not worse for you to be truthful.
Every DSIC mechanism is also BNIC, but a BNIC mechanism may exist even if no DSIC mechanism exists.
Typical examples of DSIC mechanisms are majority voting between two alternatives, and second-price auction.
Typical examples of a mechanisms that are not DSIC are plurality voting between three or more alternatives and first-price auction.
In randomized mechanisms
A randomized mechanism is a probability-distribution on deterministic mechanisms. There are two ways to define incentive-compatibility of randomized mechanisms:
The stronger definition is: a randomized mechanism is universally-incentive-compatible if every mechanism selected with positive probability is incentive-compatible (e.g. if truth-telling gives the
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https://en.wikipedia.org/wiki/Participation%20constraint%20%28mechanism%20design%29
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In game theory, and particularly mechanism design, participation constraints or individual rationality constraints are said to be satisfied if a mechanism leaves all participants at least as well-off as they would have been if they hadn't participated.
Unfortunately, it can frequently be shown that participation constraints are incompatible with other desirable properties of mechanisms for many purposes.
One kind of participation constraint is the participation criterion for voting systems. It requires that by voting, a voter should not decrease the odds of their preferred candidates winning.
See also
Individual rationality
Compensating variation
Mechanism design
Electoral system criteria
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https://en.wikipedia.org/wiki/Smalley%20%28excavator%29
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A smalley is a type of small excavator with two wheels on a single axle. It had no drive to the wheels, moving instead by pulling itself along using the excavator or 'backhoe' arm. Once in location the machine worked as any other 360° excavator, with two fixed-adjustable front legs, and two rear legs which could be mechanically height-adjusted from within the cab. For larger distances the machine could be towed on the road at moderate speeds using a suitable vehicle such as a Landrover or large van.
Smalley evolved over the years and produced the Smalley 425 which has two drive wheels and two steering wheels. It uses a Lister Diesel engine, ST1. Single Cylinder, 6.5HP . 360 Degree turn, no electrics and manual start. Later models, which are still made today, use a different engine and have an alternator to power an electric starter motor. The 1977 needed the side support or else it would be too easy to tip over. (Note: The photo is missing the cab)
Richard Smalley is credited with being the inventor of the world’s first mini excavator in 1959, although now superseded by tracked derivations of the compact excavator at the concept was highly successful in allowing a compact and cost effective machine, with these 'walking' or 'tow-behind' excavators having been sold into more than forty countries throughout the world (including over 100 machines to Japan before 1968) and hence likely being the design inspiration for these tracked compact excavators which dominate the market.
The manufacturer, Richard Smalley (Engineering) Ltd. was based in Osbournby near Sleaford in Lincolnshire, England.
References
External links
Richard Smalley Technical Services
Image of a Smalley in use
Oily Hands - Smalley Towable Diggers
Engineering vehicles
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https://en.wikipedia.org/wiki/EFI%20system%20partition
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The EFI (Extensible Firmware Interface) system partition or ESP is a partition on a data storage device (usually a hard disk drive or solid-state drive) that is used by computers having the Unified Extensible Firmware Interface (UEFI). When a computer is booted, UEFI firmware loads files stored on the ESP to start installing operating systems and various utilities.
An ESP contains the boot loaders or kernel images for all installed operating systems (which are contained in other partitions), device driver files for hardware devices present in a computer and used by the firmware at boot time, system utility programs that are intended to be run before an operating system is booted, and data files such as error logs.
Overview
The EFI system partition is formatted with a file system whose specification is based on the FAT file system and maintained as part of the UEFI specification; therefore, the file system specification is independent from the original FAT specification. The actual extent of divergence is unknown: Apple maintains a separate tool that should be used, while other systems use FAT utilities just fine. The globally unique identifier (GUID) for the EFI system partition in the GUID Partition Table (GPT) scheme is , while its ID in the master boot record (MBR) partition-table scheme is . Both GPT- and MBR-partitioned disks can contain an EFI system partition, as UEFI firmware is required to support both partitioning schemes. Also, El Torito bootable format for CD-ROMs and DVDs is supported.
UEFI provides backward compatibility with legacy systems by reserving the first block (sector) of the partition for compatibility code, effectively creating a legacy boot sector. On legacy BIOS-based systems, the first sector of a partition is loaded into memory, and execution is transferred to this code. UEFI firmware does not execute the code in the MBR, except when booting in legacy BIOS mode through the Compatibility Support Module (CSM).
The UEFI specification
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https://en.wikipedia.org/wiki/Maintenance-free%20operating%20period
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Maintenance-free operating period (MFOP) is an alternative measure of performance to the mean time between failures (MTBF), defined as the time period during which a device will be able to perform each of its intended functions, requiring only a minimal degree of maintenance. It was originally proposed in 1996 by the United Kingdom's Ministry of Defence, with intended application to military aircraft.
See also
Service life
Time between overhauls
References
Survival analysis
Reliability engineering
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https://en.wikipedia.org/wiki/Alan%20Kotok
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Alan Kotok (November 9, 1941 – May 26, 2006) was an American computer scientist known for his work at Digital Equipment Corporation (Digital, or DEC) and at the World Wide Web Consortium (W3C). Steven Levy, in his book Hackers: Heroes of the Computer Revolution, describes Kotok and his classmates at the Massachusetts Institute of Technology (MIT) as the first true hackers.
Kotok was a precocious child who skipped two grades before college. At MIT, he became a member of the Tech Model Railroad Club, and after enrolling in MIT's first freshman programming class, he helped develop some of the earliest computer software including a digital audio program and what is sometimes called the first video game (Spacewar!). Together with his teacher John McCarthy and other classmates, he was part of the team that wrote the Kotok-McCarthy program which took part in the first chess match between computers.
After leaving MIT, Kotok joined the computer manufacturer Digital Equipment Corporation (DEC), where he worked for over 30 years. He was the chief architect of the PDP-10 family of computers, and created the company's Internet Business Group, responsible for several forms of Web-based technology including the first popular search engine. Kotok is known for his contributions to the Internet and to the World Wide Web through his work at the World Wide Web Consortium, which he and Digital had helped to found, and where he served as associate chairman.
Personal life
Alan Kotok was born in Philadelphia, Pennsylvania, and was raised as an only child in Vineland, New Jersey. During his childhood, he played with tools in his father's hardware store and learned model railroading. He was a precocious child, skipping two grades at high school, and he matriculated at Massachusetts Institute of Technology (MIT) at the age of 16 in the fall of 1958 and an MBA from Clark University in 1978. Although his interest in computers began at Vineland High School, his first practical experience of c
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https://en.wikipedia.org/wiki/TrueNAS
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TrueNAS is the branding for a range of free and open-source network-attached storage (NAS) operating systems produced by iXsystems, and based on FreeBSD and Linux, using the OpenZFS file system. It is licensed under the terms of the BSD License and runs on commodity x86-64 hardware.
The TrueNAS range includes free public versions (TrueNAS CORE, previously known as FreeNAS), commercial versions (TrueNAS Enterprise), and Linux versions (TrueNAS SCALE). It also offers hardware, from small home systems to large petabyte arrays, based on the above versions.
TrueNAS supports Windows, macOS and Unix clients and various virtualization hosts such as XenServer and VMware using the SMB, AFP, NFS, iSCSI, SSH, rsync and FTP/TFTP protocols. Advanced TrueNAS features include full-disk encryption and a plug-in architecture for third-party software.
Products
TrueNAS is the brand for iXsystems' open source network attached storage platform. It includes the following:
TrueNAS CORE (previously FreeNAS) – a free file server and expandable platform based on FreeBSD.
TrueNAS Enterprise – an enterprise file server for commercial use, also based on FreeBSD.
TrueNAS SCALE – a free Linux based hyper-converged scale-out version of the TrueNAS platform.
TrueNAS hardware – Enterprise Storage Arrays, a network-attached storage (NAS) systems, storage area network (SAN) devices, and High Availability systems, with up to 22 petabytes raw capacity.
User experience
TrueNAS is managed through a comprehensive web interface that is supplemented by a minimal shell console that handles essential administrative functions. The web interface supports storage pool configuration, user management, sharing configuration and system maintenance. As an embedded system appliance, TrueNAS boots from a USB Flash device or SATA DOM. This image is configured using a USB Flash bootable installer. The TrueNAS operating system is fully independent of its storage disks, allowing its configuration database and encry
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https://en.wikipedia.org/wiki/Javier%20Barros%20Sierra
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Javier Barros Sierra (25 February 1915 – 5 May 1971) was a Mexican engineer and rector of the National Autonomous University of Mexico during the 1968 Tlatelolco massacre.
Career
Born in Mexico City, he studied civil engineering at the National Autonomous University of Mexico. He became president of the student society of the Faculty of Sciences in 1936 and University Counsellor in 1938. He taught for more than 20 years in the Escuela Nacional Preparatoria (a high school of UNAM) and the National School of Engineering (later Faculty of Engineering), of whom he was director from 1955 to 1958. He became Rector on May 5, 1966. During his rectorship, the government and the army entered Ciudad Universitaria, UNAM's main campus. In protest of these actions and the indiscriminate beating of UNAM's students, he resigned his post on September 23, 9 days before the massacre in Tlatelolco. He was reinstated as Rector after the liberation of CU, a post he held until May 5, 1970.
References
1915 births
1971 deaths
Mexican civil engineers
Engineers from Mexico City
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https://en.wikipedia.org/wiki/Nasan
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The Nasan Clustered File System is a shared disk file system created by the company DataPlow. Nasan software enables high-speed access to shared files located on shared, storage area network (SAN)-attached storage devices by utilizing the high-performance, scalable data transfers inherent to storage area networks and the manageability of network attached storage (NAS).
Nasan derives its name from the combination of network attached storage (NAS) and storage area network (SAN). Nasan clustered file sharing is an extension of traditional LAN file sharing yet utilizes storage area networks for data transfers. Deploying a Nasan cluster entails configuring LAN file sharing, installing Nasan file system software, and connecting computers and storage devices to the SAN.
Platforms
Supports Linux and Solaris operating systems.
Supports all SAN-based, block-level storage protocols including Fibre Channel and iSCSI.
References
External links
Computer file systems
Disk file systems
Network file systems
Shared disk file systems
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https://en.wikipedia.org/wiki/Memory%20disambiguation
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Memory disambiguation is a set of techniques employed by high-performance out-of-order execution microprocessors that execute memory access instructions (loads and stores) out of program order. The mechanisms for performing memory disambiguation, implemented using digital logic inside the microprocessor core, detect true dependencies between memory operations at execution time and allow the processor to recover when a dependence has been violated. They also eliminate spurious memory dependencies and allow for greater instruction-level parallelism by allowing safe out-of-order execution of loads and stores.
Background
Dependencies
When attempting to execute instructions out of order, a microprocessor must respect true dependencies between instructions. For example, consider a simple true dependence:
1: add $1, $2, $3 # R1 <= R2 + R3
2: add $5, $1, $4 # R5 <= R1 + R4 (dependent on 1)
In this example, the add instruction on line 2 is dependent on the add instruction on line 1 because the register R1 is a source operand of the addition operation on line 2. The add on line 2 cannot execute until the add on line 1 completes. In this case, the dependence is static and easily determined by a microprocessor, because the sources and destinations are registers. The destination register of the add instruction on line 1 (R1) is part of the instruction encoding, and so can be determined by the microprocessor early on, during the decode stage of the pipeline. Similarly, the source registers of the add instruction on line 2 (R1 and R4) are also encoded into the instruction itself and are determined in decode. To respect this true dependence, the microprocessor's scheduler logic will issue these instructions in the correct order (instruction 1 first, followed by instruction 2) so that the results of 1 are available when instruction 2 needs them.
Complications arise when the dependence is not statically determinable. Such non-static dependencies arise with mem
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https://en.wikipedia.org/wiki/Google%20Bookmarks
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Google Bookmarks was an online bookmarking service from Google, launched on October 10, 2005. It was an early cloud-based service that allowed users to bookmark webpages and add labels or notes. The service never became widely adopted by Google users.
Users could securely access their bookmarks on any device by signing into their Google Account. The online service was designed to store a single user's bookmarks as opposed to social and enterprise online bookmarking services that encouraged sharing bookmarks. The bookmarks were searchable, and searches were performed on the full text of the bookmark; including page title, labels and notes.
Additionally, a simple bookmarklet (JavaScript function) labeled Google Bookmark was at the bottom of the Google Bookmarks page which could be dragged to the toolbar of any browser to make bookmarking more convenient. This opened a window which simplified the process to save the bookmark to Google Bookmarks and add notes and labels.
The service was discontinued on September 30, 2021.
See also
Bookmark (digital)
Comparison of enterprise bookmarking platforms
Social bookmarking
List of social bookmarking websites
References
External links
Bookmarks
Online bookmarking services
Internet properties established in 2005
Internet properties disestablished in 2021
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https://en.wikipedia.org/wiki/Google%20Developers
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Google Developers (previously Google Code) , application programming interfaces (APIs), and technical resources. The site contains documentation on using Google developer tools and APIs—including discussion groups and blogs for developers using Google's developer products.
There are APIs offered for almost all of Google's popular consumer products, like Google Maps, YouTube, Google Apps, and others.
The site also features a variety of developer products and tools built specifically for developers. Google App Engine is a hosting service for web apps. Project Hosting gives users version control for open source code. Google Web Toolkit (GWT) allows developers to create Ajax applications in the Java programming language.(All languages)
The site contains reference information for community based developer products that Google is involved with like Android from the Open Handset Alliance and OpenSocial from the OpenSocial Foundation.
Google APIs
Google offers a variety of APIs, mostly web APIs for web developers. The APIs are based on popular Google consumer products, including Google Maps, Google Earth, AdSense, Adwords, Google Apps and YouTube.
Google Data APIs
The Google Data APIs allow programmers to create applications that read and write data from Google services. Currently, these include APIs for Google Apps, Google Analytics, Blogger, Google Base, Google Book Search, Google Calendar, Google Code Search, Google Earth, Google Spreadsheets, Google Notebook,
Ajax APIs
Google's Ajax APIs let a developer implement rich, dynamic websites entirely in JavaScript and HTML. A developer can create a map to a site, a dynamic search box, or download feeds with just a few lines of javascript.
Ads APIs
The AdSense and AdWords APIs, based on the SOAP data exchange standard, allow developers to integrate their own applications with these Google services. The AdSense API allows owners of websites and blogs to manage AdSense sign-up, content and reporting, while the AdWo
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https://en.wikipedia.org/wiki/Ring%20signature
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In cryptography, a ring signature is a type of digital signature that can be performed by any member of a set of users that each have keys. Therefore, a message signed with a ring signature is endorsed by someone in a particular set of people. One of the security properties of a ring signature is that it should be computationally infeasible to determine which of the set's members' keys was used to produce the signature. Ring signatures are similar to group signatures but differ in two key ways: first, there is no way to revoke the anonymity of an individual signature; and second, any set of users can be used as a signing set without additional setup.
Ring signatures were invented by Ron Rivest, Adi Shamir, and Yael Tauman Kalai, and introduced at ASIACRYPT in 2001. The name, ring signature, comes from the ring-like structure of the signature algorithm.
Definition
Suppose that a set of entities each have public/private key pairs, (P1, S1), (P2, S2), ..., (Pn, Sn). Party i can compute a ring signature σ on a message m, on input (m, Si, P1, ..., Pn). Anyone can check the validity of a ring signature given σ, m, and the public keys involved, P1, ..., Pn. If a ring signature is properly computed, it should pass the check. On the other hand, it should be hard for anyone to create a valid ring signature on any message for any set without knowing any of the private keys for that set.
Applications and modifications
In the original paper, Rivest, Shamir, and Tauman described ring signatures as a way to leak a secret. For instance, a ring signature could be used to provide an anonymous signature from "a high-ranking White House official", without revealing which official signed the message. Ring signatures are right for this application because the anonymity of a ring signature cannot be revoked, and because the group for a ring signature can be improvised.
Another application, also described in the original paper, is for deniable signatures. Here the sender a
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https://en.wikipedia.org/wiki/Bangladesh%20Mathematical%20Olympiad
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The Bangladesh Mathematical Olympiad is an annual mathematical competition arranged for school and college students to nourish their interest and capabilities for mathematics. It has been regularly organized by the Bangladesh Math Olympiad Committee since 2001. Bangladesh Math Olympiad activities started in 2003 formally. The first Math Olympiad was held in Shahjalal University of Science and Technology. Mohammad Kaykobad, Muhammad Zafar Iqbal and Munir Hasan were instrumental in its establishment.
With the endeavor of the members of the committee, the daily newspaper Prothom Alo and the Dutch Bangla Bank Limited, the committee promptly achieved its primary goal – to send a team to the International Mathematical Olympiad. Bangladeshi students have participated in the International Mathematical Olympiad since 2005.
Besides arranging Divisional and National Math Olympiads, the committee extends its cooperation to all interested groups and individuals who want to arrange a Mathematics Olympiad. The Bangladesh Math Olympiad and the selection of the Bangladeshi national team for the International Mathematical Olympiad is bounded by rules set by the Olympiad Committee. The Bangladesh Mathematical Olympiad is open for school and college students from the country. The competitions usually take place around December–January–February. In the 2014 International Mathematical Olympiad, the Bangladesh team achieved one silver, one bronze and four honorable mentions, placing the country at 53 among 101 participating countries. In the 2015 International Mathematical Olympiad, the Bangladesh team achieved one silver, four bronze and one honorable mention, finishing in 33rd place. Ahmed Zawad Chowdhury, who previously won a silver and a bronze in 2017 and 2016, helped Bangladesh win a gold medal for the first time in the 2018 International Mathematical Olympiad. He had previously missed a gold medal in 2017 by only two marks.
Format
The students are divided into four academic cat
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https://en.wikipedia.org/wiki/L%20pad
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An L pad is a network composed of two impedances that typically resemble the letter capital "L" when drawn on a schematic circuit diagram. It is commonly used for attenuation and for impedance matching.
Speaker L pad
A speaker L pad is a special configuration of rheostats used to control volume while maintaining a constant load impedance on the output of the audio amplifier.
It consists of a parallel and a series rheostat connected in an "L" configuration. As one increases in resistance, the other decreases, thus maintaining a constant impedance, at least in one direction. To maintain constant impedance in both directions, a "T" pad must be used. In loudspeaker systems having a crossover network, it is necessary to maintain impedance to the crossover; this avoids shifting the crossover point.
A constant-impedance load is important in the case of vacuum tube power amplifiers, because such amplifiers do not work as efficiently when terminated into an impedance greatly different than their specified output impedance. Maintaining constant impedance is less important In the case solid state electronics.
In high frequency horns, the L Pad is seen by the crossover, not the amp. L pads may not necessarily use continuously variable rheostats, but instead a multi-position rotating selector switch wired to resistors on the back. Tapped transformers are not L pads; they are autoformers. L pads can also be used at line level, mostly in pro applications.
Audio-frequency (AF) operation
The L pad attenuates the signal by having two separate rheostats connected in an "L" configuration (hence the name). One rheostat is connected in series with the loudspeaker and, as the resistance of this rheostat increases, less power is coupled into the loudspeaker and the loudness of sound produced by the loudspeaker decreases. The second rheostat is connected between the input and ground (earth). As the first rheostat increases in resistance, the second rheostat decreases in resistanc
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https://en.wikipedia.org/wiki/Transparent%20Inter-process%20Communication
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Transparent Inter Process Communication (TIPC) is an Inter-process communication (IPC) service in Linux designed for cluster-wide operation. It is sometimes presented as Cluster Domain Sockets, in contrast to the well-known Unix Domain Socket service; the latter working only on a single kernel.
Features
Some features of TIPC:
Service addressing, - address services rather than sockets
Service tracking, - subscribe for binding/unbinding of service addresses to sockets
Cluster-wide IPC service, - service location is transparent to sender
Datagram messaging with unicast, anycast and multicast, - unreliable delivery
Connection oriented messaging, - reliable delivery
Group messaging, - datagram messaging with reliable delivery
Cluster topology tracking, - subscribe for added/lost cluster nodes
Connectivity tracking, - subscribe for up/down of individual links between nodes
Automatic discovery of new cluster nodes
Scales up to 1000 nodes with second-speed failure discovery
Very good performance
Implemented as in-tree kernel module at kernel.org
Implementations
The TIPC protocol is available as a module in the mainstream Linux kernel, and hence in most Linux distributions. The TIPC project also provides open source implementations of the protocol for other operating systems including Wind River's VxWorks and Sun Microsystems' Solaris. TIPC applications are typically written in C (or C++) and utilize sockets of the AF_TIPC address family. Support for Go, D, Perl, Python, and Ruby is also available.
Service addressing
A TIPC application may use three types of addresses.
Service Address. This address type consists of a 32-bit service type identifier and a 32-bit service instance identifier. The type identifier is typically determined and hard coded by the user application programmer, but its value may have to be coordinated with other applications which might be present in the same cluster. The instance identifier is often calculated by the program, based
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https://en.wikipedia.org/wiki/Business-driven%20development
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Business-driven development is a meta-methodology for developing IT solutions that directly satisfy business requirements. This is achieved by adopting a model-driven approach that starts with the business strategy, requirements and goals, and then refines and transforms them into an IT solution. The transformation is partially achieved by applying model transformations. Due to the alignment of the business layer and the IT layer, it is possible to propagate changes of the business automatically to the IT systems. This leads to increased flexibility and shorter turnaround times when changing the business and adapting the IT systems.
Business-driven development goes further than the simple development of delivered requirements in that the implementing resource seeks to both completely understand the business side during the iterative gathering and implementing of requirements and drives to, once acquiring that information, improve business processes itself during the development of the actual solution.
The applicability of automatic models transformations to align business and IT has been criticized and partially replaced by agile practices and methods such as behavior-driven development (BDD) and domain-driven design (DDD).
See also
Behavior-driven development (BDD)
Business process automation
Business process management (BPM)
Domain-driven design (DDD)
Domain-specific modeling (DSM)
Model-driven engineering (MDE)
Service-oriented architecture (SOA)
Service-oriented modeling Framework (SOMF)
Workflow
References
Software development process
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https://en.wikipedia.org/wiki/Data%20redundancy
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In computer main memory, auxiliary storage and computer buses, data redundancy is the existence of data that is additional to the actual data and permits correction of errors in stored or transmitted data. The additional data can simply be a complete copy of the actual data (a type of repetition code), or only select pieces of data that allow detection of errors and reconstruction of lost or damaged data up to a certain level.
For example, by including computed check bits, ECC memory is capable of detecting and correcting single-bit errors within each memory word, while RAID 1 combines two hard disk drives (HDDs) into a logical storage unit that allows stored data to survive a complete failure of one drive. Data redundancy can also be used as a measure against silent data corruption; for example, file systems such as Btrfs and ZFS use data and metadata checksumming in combination with copies of stored data to detect silent data corruption and repair its effects.
In database systems
While different in nature, data redundancy also occurs in database systems that have values repeated unnecessarily in one or more records or fields, within a table, or where the field is replicated/repeated in two or more tables. Often this is found in unnormalized database designs and results in the complication of database management, introducing the risk of corrupting the data, and increasing the required amount of storage. When done on purpose from a previously normalized database schema, it may be considered a form of database denormalization; used to improve performance of database queries (shorten the database response time).
For instance, when customer data are duplicated and attached with each product bought, then redundancy of data is a known source of inconsistency since a given customer might appear with different values for one or more of their attributes. Data redundancy leads to data anomalies and corruption and generally should be avoided by design; applying database
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https://en.wikipedia.org/wiki/Packetized%20elementary%20stream
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Packetized Elementary Stream (PES) is a specification in the MPEG-2 Part 1 (Systems) (ISO/IEC 13818-1) and ITU-T H.222.0 that defines carrying of elementary streams (usually the output of an audio or video encoder) in packets within MPEG program streams and MPEG transport streams. The elementary stream is packetized by encapsulating sequential data bytes from the elementary stream inside PES packet headers.
A typical method of transmitting elementary stream data from a video or audio encoder is to first create PES packets from the elementary stream data and then to encapsulate these PES packets inside Transport Stream (TS) packets or Program Stream (PS) packets. The TS packets can then be multiplexed and transmitted using broadcasting techniques, such as those used in an ATSC and DVB.
Transport Streams and Program Streams are each logically constructed from PES packets. PES packets shall be used to convert between Transport Streams and Program Streams. In some cases the PES packets need not be modified when performing such conversions. PES packets may be much larger than the size of a Transport Stream packet.
PES packet header
Optional PES header
While above flags indicate that values are appended into variable length optional fields, they are not just simply written out. For example, PTS (and DTS) is expanded from 33 bits to 5 bytes (40 bits). If only PTS is present, this is done by catenating 0010b, most significant 3 bits from PTS, 1, following next 15 bits, 1, rest 15 bits and 1. If both PTS and DTS are present, first 4 bits for PTS are 0011 and first 4 bits for DTS are 0001. Other appended bytes have similar but different encoding.
References
External links
http://www.bretl.com/mpeghtml/pespckt.HTM
http://dvd.sourceforge.net/dvdinfo/pes-hdr.html
ISO/IEC standard 13818-1 )
MPEG
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https://en.wikipedia.org/wiki/Complex%20reflection%20group
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In mathematics, a complex reflection group is a finite group acting on a finite-dimensional complex vector space that is generated by complex reflections: non-trivial elements that fix a complex hyperplane pointwise.
Complex reflection groups arise in the study of the invariant theory of polynomial rings. In the mid-20th century, they were completely classified in work of Shephard and Todd. Special cases include the symmetric group of permutations, the dihedral groups, and more generally all finite real reflection groups (the Coxeter groups or Weyl groups, including the symmetry groups of regular polyhedra).
Definition
A (complex) reflection r (sometimes also called pseudo reflection or unitary reflection) of a finite-dimensional complex vector space V is an element of finite order that fixes a complex hyperplane pointwise, that is, the fixed-space has codimension 1.
A (finite) complex reflection group is a finite subgroup of that is generated by reflections.
Properties
Any real reflection group becomes a complex reflection group if we extend the scalars from
R to C. In particular, all finite Coxeter groups or Weyl groups give examples of complex reflection groups.
A complex reflection group W is irreducible if the only W-invariant proper subspace of the corresponding vector space is the origin. In this case, the dimension of the vector space is called the rank of W.
The Coxeter number of an irreducible complex reflection group W of rank is defined as where denotes the set of reflections and denotes the set of reflecting hyperplanes.
In the case of real reflection groups, this definition reduces to the usual definition of the Coxeter number for finite Coxeter systems.
Classification
Any complex reflection group is a product of irreducible complex reflection groups, acting on the sum of the corresponding vector spaces. So it is sufficient to classify the irreducible complex reflection groups.
The irreducible complex reflection groups were class
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https://en.wikipedia.org/wiki/Justin%20Rattner
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Justin R. Rattner is a retired Intel Senior Fellow, Corporate Vice President and former director of Intel Labs. Previously, he served as the corporation's Chief Technology Officer, where he was responsible for leading Intel's microprocessor, communications and systems technology labs and Intel Research.
In 1989, Rattner was named Scientist of the Year by R&D Magazine for his leadership in parallel and distributed computer architecture. In December 1996, Rattner was featured as Person of the Week by ABC World News for his visionary work on the Department of Energy ASCI Red System, the first computer to sustain one trillion operations per second (one teraFLOPS) and the fastest computer in the world between 1996 and 2000. In 1997, Rattner was honored as one of the Computing 200, the 200 individuals having the greatest impact on the U.S. computer industry today, and subsequently profiled in the book Wizards and Their Wonders from ACM Press.
Rattner has received two Intel Achievement Awards for his work in high performance computing and advanced cluster communication architecture. He was a longstanding member of Intel's Research Council and Academic Advisory Council. He previously served as the Intel executive sponsor for Cornell University on the External Advisory Board for the College of Engineering. Rattner joined Intel in 1973. He was named its first principal engineer in 1979, its fourth Intel Fellow in 1988, and one of the first four senior fellows in 2002.
Prior to joining Intel, Rattner held positions with Hewlett-Packard Company and Xerox Corporation. He received bachelor's and master's degrees from Cornell University in Electrical Engineering and Computer Science in 1970 and 1972, respectively. In 2012, Rattner was bestowed an honorary Doctor of Science from Willamette University in Salem, Oregon, where he delivered the commencement address to the Atkinson Graduate School of Management (AGSM).
Rattner lives near Portland, Oregon where he and his three child
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https://en.wikipedia.org/wiki/Engineering%20mathematics
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Engineering mathematics is a branch of applied mathematics concerning mathematical methods and techniques that are typically used in engineering and industry. Along with fields like engineering physics and engineering geology, both of which may belong in the wider category engineering science, engineering mathematics is an interdisciplinary subject motivated by engineers' needs both for practical, theoretical and other considerations outside their specialization, and to deal with constraints to be effective in their work.
Description
Historically, engineering mathematics consisted mostly of applied analysis, most notably: differential equations; real and complex analysis (including vector and tensor analysis); approximation theory (broadly construed, to include asymptotic, variational, and perturbative methods, representations, numerical analysis); Fourier analysis; potential theory; as well as linear algebra and applied probability, outside of analysis. These areas of mathematics were intimately tied to the development of Newtonian physics, and the mathematical physics of that period. This history also left a legacy: until the early 20th century subjects such as classical mechanics were often taught in applied mathematics departments at American universities, and fluid mechanics may still be taught in (applied) mathematics as well as engineering departments.
The success of modern numerical computer methods and software has led to the emergence of computational mathematics, computational science, and computational engineering (the last two are sometimes lumped together and abbreviated as CS&E), which occasionally use high-performance computing for the simulation of phenomena and the solution of problems in the sciences and engineering. These are often considered interdisciplinary fields, but are also of interest to engineering mathematics.
Specialized branches include engineering optimization and engineering statistics.
Engineering mathematics in tertiary educ
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https://en.wikipedia.org/wiki/Bromodeoxyuridine
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Bromodeoxyuridine (5-bromo-2'-deoxyuridine, BrdU, BUdR, BrdUrd, broxuridine) is a synthetic nucleoside analogue with a chemical structure similar to thymidine. BrdU is commonly used to study cell proliferation in living tissues and has been studied as a radiosensitizer and diagnostic tool in people with cancer.
During the S phase of the cell cycle (when DNA replication occurs), BrdU can be incorporated in place of thymidine in newly synthesized DNA molecules of dividing cells. Cells that have recently performed DNA replication or DNA repair can be detected with antibodies specific for BrdU using techniques such as immunohistochemistry or immunofluorescence. BrdU-labelled cells in humans can be detected up to two years after BrdU infusion.
Because BrdU can replace thymidine during DNA replication, it can cause mutations, and its use is therefore potentially a health hazard. However, because it is neither radioactive nor myelotoxic at labeling concentrations, it is widely preferred for in vivo studies of cancer cell proliferation. However, at radiosensitizing concentrations, BrdU becomes myelosuppressive, thus limiting its use for radiosensitizing.
BrdU differs from thymidine in that BrdU substitutes a bromine atom for thymidine's CH3 group. The Br substitution can be used in X-ray diffraction experiments in crystals containing either DNA or RNA. The Br atom acts as an anomalous scatterer and its larger size will affect the crystal's X-ray diffraction enough to detect isomorphous differences as well.
Bromodeoxyuridine releases gene silencing caused by DNA methylation.
BrdU can also be used to identify microorganisms that respond to specific carbon substrates in aquatic and soil environments. A carbon substrate added to the incubations of environmental samples will cause the growth of microorganisms that can utilize that substrate. These microorganisms will then incorporate BrdU into their DNA as they grow. Community DNA can then be isolated and BrdU-labeled DN
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https://en.wikipedia.org/wiki/Resolution%20independence
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Resolution independence is where elements on a computer screen are rendered at sizes independent from the pixel grid, resulting in a graphical user interface that is displayed at a consistent physical size, regardless of the resolution of the screen.
Concept
As early as 1978, the typesetting system TeX due to Donald Knuth introduced resolution independence into the world of computers. The intended view can be rendered beyond the atomic resolution without any artifacts, and the automatic typesetting decisions are guaranteed to be identical on any computer up to an error less than the diameter of an atom. This pioneering system has a corresponding font system, Metafont, which provides suitable fonts of the same high standards of resolution independence.
The terminology device independent file format (DVI) is the file format of Donald Knuth's pioneering TeX system. The content of such a file can be interpreted at any resolution without any artifacts, even at very high resolutions not currently in use.
Implementation
macOS
Apple included some support for resolution independence in early versions of macOS, which could be demonstrated with the developer tool Quartz Debug that included a feature allowing the user to scale the interface. However, the feature was incomplete, as some icons did not show (such as in System Preferences), user interface elements were displayed at odd positions and certain bitmap GUI elements were not scaled smoothly. Because the scaling feature was never completed, macOS's user interface remained resolution-dependent.
On June 11, 2012, Apple introduced the 2012 MacBook Pro with a resolution of 2880×1800 or 5.2 megapixels – doubling the pixel density in both dimensions. The laptop shipped with a version of macOS that provided support to scale the user interface twice as big as it has previously been. This feature is called HighDPI mode in macOS and it uses a fixed scaling factor of 2 to increase the size of the user interface for high-DPI sc
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https://en.wikipedia.org/wiki/Raritan%20Inc.
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Raritan is a multinational technology company that manufactures hardware for data center power distribution, remote server management, and audio visual solutions. The company is headquartered in Somerset, New Jersey (which is located near Raritan, New Jersey), and has a commercial presence in over 76 countries. Raritan was acquired by Legrand in September 2015.
History
Raritan was established in 1985, when the founder, Ching-I Hsu, and his wife, created a business reselling PC components out of their house. This later changed from reselling to manufacturing PCs. To make the manufacturing more efficient, Hsu developed the first KVM switch, a tool that provides a way to control numerous PCs from a single product. The KVM switch advanced Raritan as an international company and led to other company advancements.
Raritan entered the intelligent power business in 2007. Intelligent power management provides companies with an accurate measurement of the amount of energy devices use. This kind of power management is much more energy efficient because it consumes less energy/produces less heat, improves environmental conditions with sensors that adjust things like temperature and humidity levels, and overall decrease costs.
In 2008, Raritan's Data Center Infrastructure Management (DCIM) business began. This software provides the ability to better manage assets, change and capacity through monitoring of power, the environment, and energy use.
In June 2015, Legrand, North America announced an agreement to acquire Raritan. The scope of the acquisition would include Raritan's intelligent power and KVM businesses, while its Data Center Infrastructure Management (DCIM) software business would spin off into Sunbird Software, a new company and strategic partner of Raritan to be chaired by Ching-I Hsu, CEO and founder of Raritan. The acquisition was complete on September 28, 2015.
References
External links
Companies based in Somerset County, New Jersey
American companies estab
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https://en.wikipedia.org/wiki/Geometric%20Shapes%20%28Unicode%20block%29
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Geometric Shapes is a Unicode block of 96 symbols at code point range U+25A0–25FF.
U+25A0–U+25CF
The BLACK CIRCLE is displayed when typing in a password field, in order to hide characters from a screen recorder or shoulder surfing.
U+25D0–U+25FF
The CIRCLE WITH LEFT HALF BLACK is used to represent the contrast ratio of a screen.
Font coverage
Font sets like Code2000 and the DejaVu family include coverage for each of the glyphs in the Geometric Shapes range. Unifont also contains all the glyphs. Among the fonts in widespread use, full implementation is provided by Segoe UI Symbol and significant partial implementation of this range is provided by Arial Unicode MS and Lucida Sans Unicode, which include coverage for 83% (80 out of 96) and 82% (79 out of 96) of the symbols, respectively.
Block
Emoji
The Geometric Shapes block contains eight emoji:
U+25AA–U+25AB, U+25B6, U+25C0 and U+25FB–U+25FE.
The block has sixteen standardized variants defined to specify emoji-style (U+FE0F VS16) or text presentation (U+FE0E VS15) for the
eight emoji.
History
The following Unicode-related documents record the purpose and process of defining specific characters in the Geometric Shapes block:
See also
Unicode symbols
Dingbat
Box Drawing (Unicode block)
Block Elements (Unicode block)
Box-drawing character
Tombstone (typography), the end of proof character
Geometric Shapes Extended (Unicode block)
Miscellaneous Symbols and Arrows (Unicode block) includes more geometric shapes
Miscellaneous Symbols and Pictographs (Unicode block) includes several geometric shapes of different colors
Mathematical operators and symbols in Unicode
References
Unicode blocks
Geometric shapes
Geometric
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https://en.wikipedia.org/wiki/Landship
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A landship is a large land vehicle that travels exclusively on land. Its name is meant to distinguish it from vehicles that travel through other mediums such as conventional ships, airships, and spaceships.
Military committees
Landship Committee
The British Landship Committee formed during World War I to develop armored vehicles for use in trench warfare. The British proposed building "landships," super-heavy tanks capable of crossing the trench systems of the Western Front. The committee originated from the armored car division of the Royal Naval Air Service. It gained the notable support of Winston Churchill.
Military vehicles
Tank
The tank was originally referred to as the landship, owing to the continuous development from the Landship Committee. The concept of a 1,000-ton armored, fighting machine on land quickly became too impractical and too costly for it to be realistically conceived. As such, the landship project proposed a smaller vehicle. The first conceptual tank prototype was for a 300-ton vehicle that would be made by suspending a "sort of Crystal Palace body" between three enormous wheels, allegedly inspired by the Great Wheel at Earls Court in London. Six of these 'Big Wheel' landships were eventually commissioned. However, even at a revised weight, 300 tons was considered impractical given the technology present, but the influence of the big wheel would persist in the "creeping grip" tracks of the first tanks, which were wrapped around the entire body of the machine.
Mark I tank
The constant revision eventually led to the creation of the first tank. While the Mark 1 and later variations were smaller than the initial behemoths engineers envisioned, they still used naval guns, including the QF 6-pounder Hotchkiss, later shortened to the QF 6-pounder guns.
Schwerer Gustav
Schwerer Gustav was a German super heavy railway gun developed in the late 1930s. It was the largest caliber rifled weapon ever used in combat and, in terms of overall weigh
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https://en.wikipedia.org/wiki/Structure%20from%20motion
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Structure from motion (SfM) is a photogrammetric range imaging technique for estimating three-dimensional structures from two-dimensional image sequences that may be coupled with local motion signals. It is studied in the fields of computer vision and visual perception. In biological vision, SfM refers to the phenomenon by which humans (and other living creatures) can recover 3D structure from the projected 2D (retinal) motion field of a moving object or scene.
Principle
Humans perceive a great deal of information about the three-dimensional structure in their environment by moving around it. When the observer moves, objects around them move different amounts depending on their distance from the observer. This is known as motion parallax, and from this depth information can be used to generate an accurate 3D representation of the world around them.
Finding structure from motion presents a similar problem to finding structure from stereo vision. In both instances, the correspondence between images and the reconstruction of 3D object needs to be found.
To find correspondence between images, features such as corner points (edges with gradients in multiple directions) are tracked from one image to the next. One of the most widely used feature detectors is the scale-invariant feature transform (SIFT). It uses the maxima from a difference-of-Gaussians (DOG) pyramid as features. The first step in SIFT is finding a dominant gradient direction. To make it rotation-invariant, the descriptor is rotated to fit this orientation. Another common feature detector is the SURF (speeded-up robust features). In SURF, the DOG is replaced with a Hessian matrix-based blob detector. Also, instead of evaluating the gradient histograms, SURF computes for the sums of gradient components and the sums of their absolute values. Its usage of integral images allows the features to be detected extremely quickly with high detection rate. Therefore, comparing to SIFT, SURF is a faster feature de
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https://en.wikipedia.org/wiki/Osmotic%20shock
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Osmotic shock or osmotic stress is physiologic dysfunction caused by a sudden change in the solute concentration around a cell, which causes a rapid change in the movement of water across its cell membrane. Under hypertonic conditions - conditions of high concentrations of either salts, substrates or any solute in the supernatant - water is drawn out of the cells through osmosis. This also inhibits the transport of substrates and cofactors into the cell thus “shocking” the cell. Alternatively, under hypotonic conditions - when concentrations of solutes are low - water enters the cell in large amounts, causing it to swell and either burst or undergo apoptosis.
All organisms have mechanisms to respond to osmotic shock, with sensors and signal transduction networks providing information to the cell about the osmolarity of its surroundings; these signals activate responses to deal with extreme conditions. Cells that have a cell wall tend to be more resistant to osmotic shock because their cell wall enables them to maintain their shape. Although single-celled organisms are more vulnerable to osmotic shock, since they are directly exposed to their environment, cells in large animals such as mammals still suffer these stresses under some conditions. Current research also suggests that osmotic stress in cells and tissues may significantly contribute to many human diseases.
In eukaryotes, calcium acts as one of the primary regulators of osmotic stress. Intracellular calcium levels rise during hypo-osmotic and hyper-osmotic stresses.
Recovery and tolerance mechanisms
For hyper-osmotic stress
Calcium plays a large role in the recovery and tolerance for both hyper and hypo-osmotic stress situations. Under hyper-osmotic stress conditions, increased levels of intracellular calcium are exhibited. This may play a crucial role in the activation of second messenger pathways.
One example of a calcium activated second messenger molecule is MAP Kinase Hog-1. It is activated under
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https://en.wikipedia.org/wiki/Introduction%20to%20Mathematical%20Philosophy
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Introduction to Mathematical Philosophy is a book (1919 first edition) by philosopher Bertrand Russell, in which the author seeks to create an accessible introduction to various topics within the foundations of mathematics. According to the preface, the book is intended for those with only limited knowledge of mathematics and no prior experience with the mathematical logic it deals with. Accordingly, it is often used in introductory philosophy of mathematics courses at institutions of higher education.
Background
Introduction to Mathematical Philosophy was written while Russell was serving time in Brixton Prison due to his anti-war activities.
Contents
The book deals with a wide variety of topics within the philosophy of mathematics and mathematical logic including the logical basis and definition of natural numbers, real and complex numbers, limits and continuity, and classes.
Editions
Russell, Bertrand (1919), Introduction to Mathematical Philosophy, George Allen & Unwin. (Reprinted: Routledge, 1993.)
Russell, Bertrand (1920), Introduction to Mathematical Philosophy, London: George Allen & Unwin / NY: Macmillan, Second Edition, reprintings 1920, 1924, 1930.
See also
Principia Mathematica
The Principles of Mathematics
Logicism
Footnotes
Logic books
Books about philosophy of mathematics
Books by Bertrand Russell
1919 non-fiction books
Allen & Unwin books
Prison writings
Philosophy textbooks
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https://en.wikipedia.org/wiki/Bay%20mud
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Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles.
Example locations are Cape Cod Bay, Chongming Dongtan Reserve in Shanghai, China, Banc d'Arguinpreserve in Mauritania, The Bristol Channel in the United Kingdom, Mandø Island in the Wadden Sea in Denmark, Florida Bay, San Francisco Bay, Bay of Fundy, Casco Bay, Penobscot Bay, and Morro Bay.
Bay mud manifests low shear strength, high compressibility and low permeability, making it hazardous to build upon in seismically active regions like the San Francisco Bay Area.
Typical bulk density of bay mud is approximately 1.3 grams per cubic centimetre.
Bay muds often have a high organic content, consisting of decayed organisms at lower depths, but may also contain living creatures when they occur at the upper soil layer and become exposed by low tides; then, they are called mudflats, an important ecological zone for shorebirds and many types of marine organisms. Great attention was not given to the incidence of deeper bay muds until the 1960s and 1970s when development encroachment on certain North American bays intensified, requiring geotechnical design of foundations.
Bay mud has its own official geological abbreviation: the designation for Quaternary older bay mud is Qobm and the acronym for Quaternary younger bay mud is Qybm. An alluvial layer is often found overlying the older bay mud.
In relation to shipping channels, it is often necessary to dredge bay bottoms and barge the excavated material to an alternate location. In this case chemical analyses are usually performed on the bay mud to determine whether there are elevated levels of heavy metals, PCBs or other toxic substances known to accumulate in a benthic environment. It is not uncommon to dredge the same channel repeatedly (over a span of ten t
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https://en.wikipedia.org/wiki/Commissure
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A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology.
The most common usage of the term refers to the brain's commissures, of which there are five. Such a commissure is a bundle of commissural fibers as a tract that crosses the midline at its level of origin or entry (as opposed to a decussation of fibers that cross obliquely). The five are the anterior commissure, posterior commissure, corpus callosum, commissure of fornix (hippocampal commissure), and habenular commissure. They consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord there are the anterior white commissure, and the gray commissure. Commissural neurons refer to neuronal cells that grow their axons across the midline of the nervous system within the brain and the spinal cord.
Commissure also often refers to cardiac anatomy of heart valves. In the heart, a commissure is the area where the valve leaflets abut. When such an abutment is abnormally stiffened or even fused, valvular stenosis results, sometimes requiring commissurotomy.
The term may also refer to the junction of the upper and lower lips (see labial commissure of mouth).
It may refer to the junction of the upper and lower mandibles of a bird's beak, or alternately, to the full-length apposition of the closed mandibles, from the corners of the mouth to the tip of the beak.
It may refer to the nasal and temporal meeting points of the upper and lower eyelids (the medial and lateral canthi).
In female genitalia, the joining points of the two folds of the labia majora create two commissures - the anterior commissure just anterior to the prepuce of the clitoris, and the posterior commissure of the labia majora, directly posterior to the frenulum of the labia minora and anterior to the perineal raphe.
In biology, the meeting of the two valves of a brachiopod or clam is a commissure; in botany,
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https://en.wikipedia.org/wiki/Autonomic%20networking
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Autonomic Networking follows the concept of Autonomic Computing, an initiative started by IBM in 2001. Its ultimate aim is to create self-managing networks to overcome the rapidly growing complexity of the Internet and other networks and to enable their further growth, far beyond the size of today.
Increasing size and complexity
The ever-growing management complexity of the Internet caused by its rapid growth is seen by some experts as a major problem that limits its usability in the future.
What's more, increasingly popular smartphones, PDAs, networked audio and video equipment, and game consoles need to be interconnected. Pervasive Computing not only adds features, but also burdens existing networking infrastructure with more and more tasks that sooner or later will not be manageable by human intervention alone.
Another important aspect is the price of manually controlling huge numbers of vitally important devices of current network infrastructures.
Autonomic nervous system
The autonomic nervous system (ANS) is the part of the nervous system of the higher life forms that is not consciously controlled. It regulates bodily functions and the activity of specific organs. As proposed by IBM, future communication systems might be designed in a similar way to the ANS.
Components of autonomic networking
As autonomics conceptually derives from biological entities such as the human autonomic nervous system, each of the areas can be metaphorically related to functional and structural aspects of a living being. In the human body, the autonomic system facilitates and regulates a variety of functions including respiration, blood pressure and circulation, and emotive response. The autonomic nervous system is the interconnecting fabric that supports feedback loops between internal states and various sources by which internal and external conditions are monitored.
Autognostics
Autognostics includes a range of self-discovery, awareness, and analysis capabilities that p
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https://en.wikipedia.org/wiki/Arduino
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Arduino () is an Italian open-source hardware and software company, project, and user community that designs and manufactures single-board microcontrollers and microcontroller kits for building digital devices. Its hardware products are licensed under a CC BY-SA license, while the software is licensed under the GNU Lesser General Public License (LGPL) or the GNU General Public License (GPL), permitting the manufacture of Arduino boards and software distribution by anyone. Arduino boards are available commercially from the official website or through authorized distributors.
Arduino board designs use a variety of microprocessors and controllers. The boards are equipped with sets of digital and analog input/output (I/O) pins that may be interfaced to various expansion boards ('shields') or breadboards (for prototyping) and other circuits. The boards feature serial communications interfaces, including Universal Serial Bus (USB) on some models, which are also used for loading programs. The microcontrollers can be programmed using the C and C++ programming languages(Embedded C), using a standard API which is also known as the Arduino Programming Language, inspired by the Processing language and used with a modified version of the Processing IDE. In addition to using traditional compiler toolchains, the Arduino project provides an integrated development environment (IDE) and a command line tool developed in Go.
The Arduino project began in 2005 as a tool for students at the Interaction Design Institute Ivrea, Italy, aiming to provide a low-cost and easy way for novices and professionals to create devices that interact with their environment using sensors and actuators. Common examples of such devices intended for beginner hobbyists include simple robots, thermostats, and motion detectors.
The name Arduino comes from a bar in Ivrea, Italy, where some of the project's founders used to meet. The bar was named after Arduin of Ivrea, who was the margrave of the March of Ivr
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https://en.wikipedia.org/wiki/Dipotassium%20phosphate
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Dipotassium phosphate (K2HPO4) (also dipotassium hydrogen orthophosphate; potassium phosphate dibasic) is the inorganic compound with the formula K2HPO4.(H2O)x (x = 0, 3, 6). Together with monopotassium phosphate (KH2PO4.(H2O)x), it is often used as a fertilizer, food additive, and buffering agent. It is a white or colorless solid that is soluble in water.
It is produced commercially by partial neutralization of phosphoric acid with two equivalents of potassium chloride:
H3PO4 + 2 KCl → K2HPO4 + 2 HCl
Uses
As a food additive, dipotassium phosphate is used in imitation dairy creamers, dry powder beverages, mineral supplements, and starter cultures. It functions as an emulsifier, stabilizer and texturizer; it also is a buffering agent, and chelating agent especially for the calcium in milk products..
As a food additive, dipotassium phosphate is generally recognized as safe by the United States Food and Drug Administration.
References
Potassium compounds
Phosphates
Acid salts
Food additives
E-number additives
Inorganic fertilizers
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https://en.wikipedia.org/wiki/Operability
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Operability is the ability to keep a piece of equipment, a system or a whole industrial installation in a safe and reliable functioning condition, according to pre-defined operational requirements.
In a computing systems environment with multiple systems this includes the ability of products, systems and business processes to work together to accomplish a common task such as finding and returning availability of inventory for flight.
For a gas turbine engine, operability addresses the installed aerodynamic operation of the engine to ensure that it operates with care-free throttle handling without compressor stall or surge or combustor flame-out. There must be no unacceptable loss of power or handling deterioration after ingesting birds, rain and hail or ingesting or accumulating ice. Design and development responsibilities include the components through which the thrust/power-producing flow passes, ie the intake, compressor, combustor, fuel system, turbine and exhaust. They also include the software in the computers which control the way the engine changes its speed in response to the actions of the pilot in selecting a start, selecting different idle settings and higher power ratings such as take-off, climb and cruise. The engine has to start to idle and accelerate and decelerate within agreed, or mandated, times while remaining within operating limits (shaft speeds, turbine temperature, combustor casing pressure) over the required aircraft operating envelope.
Operability is considered one of the ilities and is closely related to reliability, supportability and maintainability.
Operability also refers to whether or not a surgical operation can be performed to treat a patient with a reasonable degree of safety and chance of success.
References
External links
Software Operability
Examples Software Operability Requirements
Computer systems
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https://en.wikipedia.org/wiki/Scophony
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Scophony was a sophisticated mechanical television system developed in Britain by Scophony Limited. A black and white image was produced by an early form of acousto-optic modulation of a bright light using a piezoelectric crystal and water or other transparent liquid column.
Principle of operation
The light modulator worked as follows. Crystal vibrations at one end of a horizontal water column would cause waves to propagate through the water. The light was passed through this column from the side across the waves as they propagated through the column, via separate horizontal and vertical orientated cylindrical lenses. The vibrations through the water would act as a diffraction grating, the higher the amplitude, the more that the light passing through would be diffracted. The light passed through the water column was then horizontally focussed onto either a slit or narrow optical block, depending on whether positive or negative modulation of the water column was used. The amount of light which would either pass through the slit or go around the block depended on the amplitude of the modulation, thereby causing the light amplitude to be modulated. Following the slit/block, the light would hit the high speed horizontal rotating mirror drum which was synchronised to the propagation of the waves through the water bath, in order that a particular wave in the water bath would appear at a fixed position on the screen, although that wave would actually be moving through the water column. This technique allowed significantly more of the light from the light source to be used compared to previous light modulation techniques. Vertical scanning was achieved by a separate much larger rotating mirror drum.
It is a common misconception that the water column would contain a complete video line, but this was not necessary with the Scophony system.
Innovation
Scophony's system used several innovative devices:
A split horizontal and vertical focus optical system invented by Wal
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https://en.wikipedia.org/wiki/Cave%20survey
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A cave survey is a map of all or part of a cave system, which may be produced to meet differing standards of accuracy depending on the cave conditions and equipment available underground. Cave surveying and cartography, i.e. the creation of an accurate, detailed map, is one of the most common technical activities undertaken within a cave and is a fundamental part of speleology. Surveys can be used to compare caves to each other by length, depth and volume, may reveal clues on speleogenesis, provide a spatial reference for other areas of scientific study and assist visitors with route-finding.
Traditionally, cave surveys are produced in two-dimensional form due to the confines of print, but given the three-dimensional environment inside a cave, modern techniques using computer aided design are increasingly used to allow a more realistic representation of a cave system.
History
The first known plan of a cave dates from 1546, and was of a man-made cavern in tufa called the Stufe di Nerone (Nero's Oven) in Pozzuoli near Naples in Italy. The first natural cave to be mapped was the Baumannshöhle in Germany, of which a sketch from 1656 survives.
Another early survey dates from before 1680, and was made by John Aubrey of Long Hole in the Cheddar Gorge. It consists of an elevational section of the cave. Numerous other surveys of caves were made in the following years, though most are sketches and are limited in accuracy. The first cave that is likely to have been accurately surveyed with instruments is the Grotte de Miremont in France. This was surveyed by a civil engineer in 1765 and includes numerous cross-sections. Édouard-Alfred Martel was the first person to describe surveying techniques. His surveys were made by having an assistant walk down the passage until they were almost out of sight. Martel would then take a compass bearing to the assistant's light, and measure the distance by pacing up to the assistant. This would equate to a modern-day BCRA Grade 2 survey.
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https://en.wikipedia.org/wiki/Filter%20cake
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A filter cake is formed by the substances that are retained on a filter. Filter aids, such as diatomaceous earth or activated carbon are usually used to form the filter cake. The purpose is to increase flow rate or achieve a smaller micron filtration. The filter cake grows in the course of filtration, becoming "thicker" as particulate matter and filter aid is retained on the filter.
With increasing layer thickness, the flow resistance of the filter cake increases. After a time, the filter cake has to be removed from the filter, e.g. by backflushing. If this is not accomplished, the filtration is disrupted because the viscosity of the filter cake gets too high; hence, too little of the mixture to be filtered can pass through the filter cake, and the filter becomes plugged or clogged. The specifications of the filter cake dictate the filtration method of choice.
See also
Filter press
Press cake
Tilting pan filter
References
Filters
Water treatment
Water technology
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https://en.wikipedia.org/wiki/History%20of%20Programming%20Languages%20%28conference%29
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History of Programming Languages (HOPL) is an infrequent ACM SIGPLAN conference. Past conferences were held in 1978, 1993, and 2007. The fourth conference was originally intended to take place in June 2020, but was postponed to 2021.
HOPL I
HOPL I was held June 1 – 3, 1978 in Los Angeles, California. Jean E. Sammet was both the general and program committee chair. John A. N. Lee was the administrative chair. Richard L. Wexelblat was the proceedings chair. From Sammet's introduction: The HOPL Conference "is intended to consider the technical factors which influenced the development of certain selected programming languages." The languages and presentations in the first HOPL were by invitation of the program committee. The invited languages must have been created and in use by 1967. They also must have remained in use in 1977. Finally, they must have had considerable influence on the field of computing.
The papers and presentations went through extensive review by the program committee (and revisions by the authors), far beyond the norm for conferences and commensurate with some of the best journals in the field.
Preprints of the proceedings were published in SIGPLAN Notices (volume 13, issue 8, August 1978). The final proceedings, including transcripts of question and answer sessions, was published as a book in the ACM Monograph Series: History of Programming Languages, edited by Wexelblat (Academic press, 1981).
HOPL II
HOPL II was held April 20–23, 1993 in Cambridge, Massachusetts. John A.N. Lee was the conference chair and Sammet again was the program chair. In contrast to HOPL I, HOPL II included both invited papers and papers submitted in response to an open call. The scope also expanded. Where HOPL I had only papers on the early history of languages, HOPL II solicited contributions on:
early history of specific languages,
evolution of a language,
history of language features and concepts, and
classes of languages for application-oriented languages and p
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https://en.wikipedia.org/wiki/OS2000
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Baget RTOS (rus. ОСРВ Багет) is a real-time operating system developed by the Scientific Research Institute of System Development of the Russian Academy of Sciences for a MIPS architecture (Baget-MIPS variant) and Intel board support packages (BSPs) (x86 architecture). Baget is intended for software execution in a hard real-time embedded systems (firmware).
X Window System (client and server) was ported to Baget. It also has Ethernet support (Network File System (NFS), File Transfer Protocol (FTP), Telnet protocols), long filename File Allocation Table (VFAT) and a tar file systems, floppy disk drive (FDD) and hard disk drive (HDD) driver support. Several supported network cards are limited by some Realtek Industry Standard Architecture (ISA) and Peripheral Component Interconnect (PCI) cards.
The development process is based on the following principles:
international standards compliance
portability
Scalability
Microkernel
Object-oriented programming
Cross-platform development
Standards compliance
Portable Operating System Interface (POSIX) 1003.1, standard (application programming interface (API)),
C standard programming language and libraries.
See also
Comparison of real-time operating systems
External links
NIISI RAS Baget RTOS
NIISI RAS
MCST-R500 1 GHz CPU for Baget RTOS
Real-time operating systems
Embedded operating systems
Microkernel-based operating systems
Microkernels
MIPS operating systems
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https://en.wikipedia.org/wiki/Bit%20Rate%20Reduction
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Bit Rate Reduction, or BRR, also called Bit Rate Reduced, is a name given to
an audio compression method used on the SPC700 sound coprocessor used in the SNES, as well as the audio processors of the Philips CD-i, the PlayStation, and the Apple Macintosh Quadra series. The method is a form of ADPCM.
BRR compresses each consecutive sequence of sixteen 16-bit PCM samples into a block of 9 bytes. From most to least significant, the first byte of each block consists of four bits indicating the range of the block (see below) which controls the size of steps between the 16 possible values such that minute changes can be recorded if the 16 values are closer together but minute changes are lost if the 16 values are far apart, two bits indicating the filter (see below), and two bits of control information for the SPC700. The remaining eight bytes consist of 16 signed 4-bit nibbles which correspond to the 16 samples, packed in a big-endian manner. As 32 bytes of input become 9 bytes of output, the BRR algorithm yields a 3.56:1 compression ratio.
Decompression algorithm
A nibble n in a block with filter and range should be decoded into a PCM sample using the following second-order linear prediction equation:
Here, and are the last-output and next-to-last-output PCM samples, respectively. The filter type is translated into IIR prediction coefficients using the following table:
These calculations are all done in signed 16.16 fixed-point arithmetic.
Or in words:
Filter 0 linearly decodes the bit downquantized version of the samples.
Filter 1 adds an bit downquantized version of the samples to a lowered previous input (delta pack or differential coding).
Filters 2 and 3 add an bit downquantized version of the samples to the linear extrapolation from the last two samples (2nd order differential coding).
The coefficients of the above filters are specified as slightly less than 1 or 2 in order to realize a leaky integrator that is more resilient to errors in th
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https://en.wikipedia.org/wiki/Martian%20language
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Martian language (), sometimes also called brain-disabled characters (), is the nickname of unconventional representation of Chinese characters online. "Martian" describes that which seems strange to local culture. The term was popularised by a line from the 2001 Hong Kong comedy Shaolin Soccer, in which Sing (Stephen Chow) tells Mui (Zhao Wei): "Go back to Mars. The Earth is so dangerous."
In the 2006 General Scholastic Ability Test of Taiwan, students were asked to interpret symbols and phrases written in "Martian language" based on contexts written in standard language. Controversies which followed forced the testing center to abandon the practice in future exams.
In 2007, Martian language began to catch on in mainland China. The first adopters of Martian language mainly consisted of Post-90s netizens. They use it in their nicknames, short messages, and chat rooms in order to demonstrate personality differences. Later, they found that their teachers and parents could hardly figure out their new language, which quickly became their secret code to communicate with each other. Chinese online bloggers followed up the trend to use Martian language, because they found that their blog posts written in the new language can easily pass Internet censorship engines, which are currently based on text-matching techniques. The Martian language became so popular in cyberspace that software were created to translate between Chinese and Martian language.
General aspects
The Martian language is written from Chinese by means of various substitution methods. Just like in l33t, where the letter "e" is replaced by the number "3", in Martian, standard Chinese characters are replaced with nonstandard ones, or foreign scripts. Each Chinese character may be replaced with:
A character that is a (quasi-)homophone
A character that looks similar, such as one with a shared radical
A character with the same or similar meaning
The character used for substitution can include not only Chine
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https://en.wikipedia.org/wiki/Pirate%20game
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The pirate game is a simple mathematical game. It is a multi-player version of the ultimatum game.
The game
There are five rational pirates (in strict order of seniority A, B, C, D and E) who found 100 gold coins. They must decide how to distribute them.
The pirate world's rules of distribution say that the most senior pirate first proposes a plan of distribution. The pirates, including the proposer, then vote on whether to accept this distribution. If the majority accepts the plan, the coins are disbursed and the game ends. In case of a tie vote, the proposer has the casting vote. If the majority rejects the plan, the proposer is thrown overboard from the pirate ship and dies, and the next most senior pirate makes a new proposal to begin the system again. The process repeats until a plan is accepted or if there is one pirate left.
Pirates base their decisions on four factors:
Each pirate wants to survive.
Given survival, each pirate wants to maximize the number of gold coins he receives.
Each pirate would prefer to throw another overboard, if all other results would otherwise be equal.
The pirates do not trust each other, and will neither make nor honor any promises between pirates apart from a proposed distribution plan that gives a whole number of gold coins to each pirate.
The result
To increase the chance of their plan being accepted, one might expect that Pirate A will have to offer the other pirates most of the gold. However, this is far from the theoretical result. When each of the pirates votes, they will not just be thinking about the current proposal, but also other outcomes down the line. In addition, the order of seniority is known in advance so each of them can accurately predict how the others might vote in any scenario. This becomes apparent if we work backwards.
The final possible scenario would have all the pirates except D and E thrown overboard. Since D is senior to E, they have the casting vote; so, D would propose to keep 100 for themself
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https://en.wikipedia.org/wiki/Blue%20Mesa%20Reservoir
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Blue Mesa Reservoir is an artificial reservoir located on the upper reaches of the Gunnison River in Gunnison County, Colorado. The largest lake located entirely within the state, Blue Mesa Reservoir was created by the construction of Blue Mesa Dam, a tall earthen fill dam constructed on the Gunnison by the U.S. Bureau of Reclamation in 1966 for the generation of hydroelectric power. Managed as part of the Curecanti National Recreation Area, a unit of the National Park Service, Blue Mesa Reservoir is the largest lake trout and Kokanee salmon fishery in Colorado.
History
In 1956, the U.S. Bureau of Reclamation was given the responsibility, under the Colorado River Storage Project Act, to begin planning and construction of the Colorado River Storage Project (CRSP), a series of projects in Colorado, New Mexico, Utah, and Wyoming that would make possible comprehensive development of the waters of the Colorado River and its major tributaries. One of the initial projects of the CRSP, the Curecanti Unit, focused on the upper reaches of the Gunnison River, the fifth-largest tributary of the Colorado River. The centerpiece of the plans for the Gunnison was the construction of four dams on a of the river east of the National Park Service's Black Canyon of the Gunnison National Park, projects that would not only help control the amount of water flowing into the Colorado, but would also create new opportunities for flood control, water storage, and the generation of hydroelectric power. The first of these dams was Blue Mesa Dam, which was begun in 1962 approximately west of Gunnison, and west of Sapinero. Finished four years later, the dam created Blue Mesa Reservoir, which became the primary water storage reservoir for the Curecanti Unit (later renamed the Wayne N. Aspinall Unit).
Climate
According to the Köppen Climate Classification system, Blue Mesa Reservoir has a warm-summer humid continental climate, abbreviated "Dfb" on climate maps. The hottest temperature
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https://en.wikipedia.org/wiki/Blue%20Mesa%20Dam
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Blue Mesa Dam is a zoned earthfill dam on the Gunnison River in Colorado. It creates Blue Mesa Reservoir, and is within Curecanti National Recreation Area just before the river enters the Black Canyon of the Gunnison. The dam is upstream of the Morrow Point Dam. Blue Mesa Dam and reservoir are part of the Bureau of Reclamation's Wayne N. Aspinall Unit of the Colorado River Storage Project, which retains the waters of the Colorado River and its tributaries for agricultural and municipal use in the American Southwest. Although the dam does produce hydroelectric power, its primary purpose is water storage. State Highway 92 passes over the top of the dam. Blue Mesa Dam houses two turbine generators and produces an average of 264,329,000 kilowatt-hours each year.
Description
The dam stands in an area where sandstone and shale overlay pre-Cambrian granite, schist and gneiss. It is situated at a narrows in the river valley where the Gunnison enters the upper reaches of the Black Canyon of the Gunnison. The dam has a volume of and the spillway intake structure has two radial gates. These discharge into a concrete-lined tunnel which in turn discharges through a flip bucket into a stilling basin.
History
The Curecanti Project (later renamed the Wayne N. Aspinall Project) was conceived in 1955, initially with four dams. It was approved by the Secretary of the Interior in 1959, comprising Blue Mesa Dam and Morrow Point Dam. Crystal Dam's design was unfinished and was approved in 1962. Plans for a fourth dam were dropped as uneconomical. The project was restricted to the stretch of the Gunnison above Black Canyon of the Gunnison National Monument (later designated a national park), a length of the river. Initially planned as a concrete dam, the project was changed to an earth-fill design.
Work on the dam started in 1961, with foundation drilling and survey work. Construction of the reservoir required the relocation of US 50 and State Highway 149. This relocation was a
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https://en.wikipedia.org/wiki/270%20%28number%29
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270 (two hundred [and] seventy) is the natural number following 269 and preceding 271.
In mathematics
270 is a harmonic divisor number
270 is the fourth number that is divisible by its average integer divisor
References
Integers
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https://en.wikipedia.org/wiki/Morrow%20Point%20Dam
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Morrow Point Dam is a concrete double-arch dam on the Gunnison River located in Colorado, the first dam of its type built by the U.S. Bureau of Reclamation. Located in the upper Black Canyon of the Gunnison, it creates Morrow Point Reservoir, and is within the National Park Service-operated Curecanti National Recreation Area. The dam is between the Blue Mesa Dam (upstream) and the Crystal Dam (downstream). Morrow Point Dam and reservoir are part of the Bureau of Reclamation's Wayne N. Aspinall Unit of the Colorado River Storage Project, which retains the waters of the Colorado River and its tributaries for agricultural and municipal use in the American Southwest. The dam's primary purpose is hydroelectric power generation.
Description
The dam, powerplant and reservoir are contained in pre-Cambrian metamorphic rocks, primarily micaceous quartzite, quartz-mica, mica and biotite schists, with granitic veining. The dam site is in a narrow canyon about wide at the river and wide at the top. The spillway discharge falls into a stilling basin whose waters are retained by a weir below the dam. Intake structures near the south abutment feed two diameter penstock tunnels with steel linings leading to the powerplant. A streamflow of is maintained at all times, equivalent to per day.
History
The Curecanti Project (later renamed the Wayne N. Aspinall Project) was conceived in 1955, initially with four dams. It was approved by the Secretary of the Interior in 1959, comprising Blue Mesa Dam and Morrow Point Dam. Crystal Dam's design was unfinished and was approved in 1962. Plans for a fourth dam were dropped as uneconomical. The project was restricted to the stretch of the Gunnison above Black Canyon of the Gunnison National Monument (later designated a national park), a length of the river. Work began at the damsite in 1961 with foundation drilling. In 1962 the power plant exploratory tunnel was excavated. The construction contract for the dam was awarded to a join
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https://en.wikipedia.org/wiki/Cleaner%20production
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Cleaner production is a preventive, company-specific environmental protection initiative. It is intended to minimize waste and emissions and maximize product output. By analysing the flow of materials and energy in a company, one tries to identify options to minimize waste and emissions out of industrial processes through source reduction strategies. Improvements of organisation and technology help to reduce or suggest better choices in use of materials and energy, and to avoid waste, waste water generation, and gaseous emissions, and also waste heat and noise.
Overview
The concept was developed during the preparation of the Rio Summit as a programme of UNEP (United Nations Environmental Programme) and UNIDO (United Nations Industrial Development Organization) under the leadership of Jacqueline Aloisi de Larderel, the former Assistant Executive Director of UNEP. The programme was meant to reduce the environmental impact of industry. It built on ideas used by the company 3M in its 3P programme (pollution prevention pays). It has found more international support than all other comparable programmes. The programme idea was described "...to assist developing nations in leapfrogging from pollution to less pollution, using available technologies". Starting from the simple idea to produce with less waste Cleaner Production was developed into a concept to increase the resource efficiency of production in general. UNIDO has been operating National Cleaner Production Centers and Programmes (NCPCs/NCPPs) with centres in Latin America, Africa, Asia and Europe.
Cleaner production is endorsed by UNEP's International Declaration on Cleaner Production, "a voluntary and public statement of commitment to the practice and promotion of Cleaner Production". Implementing guidelines for cleaner production were published by UNEP in 2001.
In the US, the term pollution prevention is more commonly used for cleaner production.
Options
Examples for cleaner production options are:
Documen
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https://en.wikipedia.org/wiki/Crystal%20Dam
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Crystal Dam is a , double-curvature, concrete, thin arch dam located 6 miles downstream from Morrow Point Dam on the Gunnison River in Colorado, United States. Crystal Dam is the newest of the three dams in Curecanti National Recreation Area; construction on the dam was finished in 1976. The dam impounds Crystal Reservoir. Crystal Dam and Reservoir are part of the Bureau of Reclamation's Wayne N. Aspinall Unit of the Colorado River Storage Project, which retains the waters of the Gunnison River and its tributaries for agricultural and municipal use in the American Southwest. The dam's primary purpose is hydroelectric power generation.
Description
Crystal Dam, like the higher Morrow Point Dam farther upstream, is a thin-shell arch dam, primarily planned to generate hydroelectric power. Unlike its upstream companions, excess water spills over the top of the dam through a notched-out, ungated spillway that can create a waterfall in times of overflow. Under normal conditions the river flows through an diameter penstock to the 28 MW turbine. The dam is deep within the Black Canyon of the Gunnison in pre-Cambrian metamorphic rock.
History
Crystal Dam was the last of the three dams in the Aspinall Unit of the Colorado River Storage Project to be completed. Crystal Dam's design and construction lagged behind Morrow Point and Blue Mesa dams. Construction started in 1964 on a materials borrow pit, with construction at the damsite beginning in 1965 for an access road and exploratory drilling. Work then stopped for five years. Initially planned as an earth-fill dam, the design was changed to a double-curvature, thin-shell concrete arch dam. After an initial bidding process in which all bid were rejected as too high, a contract for the diversion tunnel was awarded in 1972, which was holed through the same year. The construction contract for the dam itself was awarded to the J.F. Shea Company in June 1973. Cofferdam work continued into 1974, encountering problems with leaka
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https://en.wikipedia.org/wiki/Megaspore
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Megaspores, also called macrospores, are a type of spore that is present in heterosporous plants. These plants have two spore types, megaspores and microspores. Generally speaking, the megaspore, or large spore, germinates into a female gametophyte, which produces egg cells. These are fertilized by sperm produced by the male gametophyte developing from the microspore. Heterosporous plants include seed plants (gymnosperms and flowering plants), water ferns (Salviniales), spikemosses (Selaginellaceae) and quillworts (Isoetaceae).
Megasporogenesis
In gymnosperms and flowering plants, the megaspore is produced inside the nucellus of the ovule. During megasporogenesis, a diploid precursor cell, the megasporocyte or megaspore mother cell, undergoes meiosis to produce initially four haploid cells (the megaspores). Angiosperms exhibit three patterns of megasporogenesis: monosporic, bisporic, and tetrasporic, also known as the Polygonum type, the Alisma type, and the Drusa type, respectively. The monosporic pattern occurs most frequently (>70% of angiosperms) and is found in many economically and biologically important groups such as Brassicaceae (e.g., Arabidopsis, Capsella, Brassica), Gramineae (e.g., maize, rice, wheat), Malvaceae (e.g., cotton), Leguminoseae (e.g., beans, soybean), and Solanaceae (e.g., pepper, tobacco, tomato, potato, petunia).
This pattern is characterized by cell plate formation after meiosis 1 & 2, which results in four one-nucleate megaspores, of which three degenerate. The bisporic pattern is characterized by cell plate formation only after meiosis 1, and results in two two-nucleate megaspores, of which one degenerates. The tetrasporic pattern is characterized by cell plates failing to form after either meiosis 1 or 2, and results in one four-nucleate megaspore. Therefore, each pattern gives rise to a single functional megaspore which contains one, two, or four meiotic nuclei, respectively. The megaspore then undergoes megagametogenesis to g
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https://en.wikipedia.org/wiki/Open%E2%80%93closed%20principle
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In object-oriented programming, the open–closed principle (OCP) states "software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification";
that is, such an entity can allow its behaviour to be extended without modifying its source code.
The name open–closed principle has been used in two ways. Both ways use generalizations (for instance, inheritance or delegate functions) to resolve the apparent dilemma, but the goals, techniques, and results are different.
Open–closed principle is one of the five SOLID principles of object-oriented design.
Meyer's open–closed principle
Bertrand Meyer is generally credited for having originated the term open–closed principle, which appeared in his 1988 book Object Oriented Software Construction.
A module will be said to be open if it is still available for extension. For example, it should be possible to add fields to the data structures it contains, or new elements to the set of functions it performs.
A module will be said to be closed if [it] is available for use by other modules. This assumes that the module has been given a well-defined, stable description (the interface in the sense of information hiding).
At the time Meyer was writing, adding fields or functions to a library inevitably required changes to any programs depending on that library. Meyer's proposed solution to this dilemma relied on the notion of object-oriented inheritance (specifically implementation inheritance):
A class is closed, since it may be compiled, stored in a library, baselined, and used by client classes. But it is also open, since any new class may use it as parent, adding new features. When a descendant class is defined, there is no need to change the original or to disturb its clients.
Polymorphic open–closed principle
During the 1990s, the open–closed principle became popularly redefined to refer to the use of abstracted interfaces, where the implementations can be changed and multiple impl
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https://en.wikipedia.org/wiki/Haxe
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Haxe is a high-level cross-platform programming language and compiler that can produce applications and source code for many different computing platforms from one code-base. It is free and open-source software, released under the MIT License. The compiler, written in OCaml, is released under the GNU General Public License (GPL) version 2.
Haxe includes a set of features and a standard library supported across all platforms, like numeric data types, strings, arrays, maps, binary, reflection, maths, Hypertext Transfer Protocol (HTTP), file system and common file formats. Haxe also includes platform-specific API's for each compiler target. Kha, OpenFL and Heaps.io are popular Haxe frameworks that enable creating multi-platform content from one codebase.
Haxe originated with the idea of supporting client-side and server-side programming in one language, and simplifying the communication logic between them. Code written in the Haxe language can be compiled into JavaScript, C++, Java, JVM, PHP, C#, Python, Lua and Node.js. Haxe can also directly compile SWF, HashLink, and NekoVM bytecode and also runs in interpreted mode.
Haxe supports externs (definition files) that can contain type information of existing libraries to describe target-specific interaction in a type-safe manner, like C++ header files can describe the structure of existing object files. This enables to use the values defined in the files as if they were statically typed Haxe entities. Beside externs, other solutions exist to access each platform's native capabilities.
Many popular IDEs and source code editors have support available for Haxe development. No particular development environment or tool set is officially recommended by the Haxe Foundation, although VS Code, IntelliJ IDEA and HaxeDevelop have the most support for Haxe development. The core functionalities of syntax highlighting, code completion, refactoring, debugging, etc. are available to various degrees.
History
Development of Haxe bega
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https://en.wikipedia.org/wiki/Heath-Brown%E2%80%93Moroz%20constant
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The Heath-Brown–Moroz constant C, named for Roger Heath-Brown and Boris Moroz, is defined as
where p runs over the primes.
Application
This constant is part of an asymptotic estimate for the distribution of rational points of bounded height on the cubic surface X03=X1X2X3. Let H be a positive real number and N(H) the number of solutions to the equation X03=X1X2X3 with all the Xi non-negative integers less than or equal to H and their greatest common divisor equal to 1. Then
References
External links
Wolfram Mathworld's article
Mathematical constants
Infinite products
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https://en.wikipedia.org/wiki/Consensus%20%28computer%20science%29
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A fundamental problem in distributed computing and multi-agent systems is to achieve overall system reliability in the presence of a number of faulty processes. This often requires coordinating processes to reach consensus, or agree on some data value that is needed during computation. Example applications of consensus include agreeing on what transactions to commit to a database in which order, state machine replication, and atomic broadcasts. Real-world applications often requiring consensus include cloud computing, clock synchronization, PageRank, opinion formation, smart power grids, state estimation, control of UAVs (and multiple robots/agents in general), load balancing, blockchain, and others.
Problem description
The consensus problem requires agreement among a number of processes (or agents) for a single data value. Some of the processes (agents) may fail or be unreliable in other ways, so consensus protocols must be fault tolerant or resilient. The processes must somehow put forth their candidate values, communicate with one another, and agree on a single consensus value.
The consensus problem is a fundamental problem in control of multi-agent systems. One approach to generating consensus is for all processes (agents) to agree on a majority value. In this context, a majority requires at least one more than half of available votes (where each process is given a vote). However, one or more faulty processes may skew the resultant outcome such that consensus may not be reached or reached incorrectly.
Protocols that solve consensus problems are designed to deal with limited numbers of faulty processes. These protocols must satisfy a number of requirements to be useful. For instance, a trivial protocol could have all processes output binary value 1. This is not useful and thus the requirement is modified such that the output must somehow depend on the input. That is, the output value of a consensus protocol must be the input value of some process. Another requ
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https://en.wikipedia.org/wiki/Interkinesis
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Interkinesis or interphase II is a period of rest that cells of some species enter during meiosis between meiosis I and meiosis II. No DNA replication occurs during interkinesis; however, replication does occur during the interphase I stage of meiosis (See meiosis I). During interkinesis, the spindles of the first meiotic division disassembles and the microtubules reassemble into two new spindles for the second meiotic division. Interkinesis follows telophase I; however, many plants skip telophase I and interkinesis, going immediately into prophase II. Each chromosome still consists of two chromatids. In this stage other organelle number may also increase.
References
Cellular processes
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https://en.wikipedia.org/wiki/Sum%20of%20angles%20of%20a%20triangle
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In a Euclidean space, the sum of angles of a triangle equals the straight angle (180 degrees, radians, two right angles, or a half-turn).
A triangle has three angles, one at each vertex, bounded by a pair of adjacent sides.
It was unknown for a long time whether other geometries exist, for which this sum is different. The influence of this problem on mathematics was particularly strong during the 19th century. Ultimately, the answer was proven to be positive: in other spaces (geometries) this sum can be greater or lesser, but it then must depend on the triangle. Its difference from 180° is a case of angular defect and serves as an important distinction for geometric systems.
Cases
Euclidean geometry
In Euclidean geometry, the triangle postulate states that the sum of the angles of a triangle is two right angles. This postulate is equivalent to the parallel postulate. In the presence of the other axioms of Euclidean geometry, the following statements are equivalent:
Triangle postulate: The sum of the angles of a triangle is two right angles.
Playfair's axiom: Given a straight line and a point not on the line, exactly one straight line may be drawn through the point parallel to the given line.
Proclus' axiom: If a line intersects one of two parallel lines, it must intersect the other also.
Equidistance postulate: Parallel lines are everywhere equidistant (i.e. the distance from each point on one line to the other line is always the same.)
Triangle area property: The area of a triangle can be as large as we please.
Three points property: Three points either lie on a line or lie on a circle.
Pythagoras' theorem: In a right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides.
Hyperbolic geometry
The sum of the angles of a hyperbolic triangle is less than 180°. The relation between angular defect and the triangle's area was first proven by Johann Heinrich Lambert.
One can easily see how hyperbolic geometry breaks Playf
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https://en.wikipedia.org/wiki/State%20machine%20replication
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In computer science, state machine replication (SMR) or state machine approach is a general method for implementing a fault-tolerant service by replicating servers and coordinating client interactions with server replicas. The approach also provides a framework for understanding and designing replication management protocols.
Problem definition
Distributed service
In terms of clients and services. Each service comprises one or more servers and exports operations that clients invoke by making requests. Although using a single, centralized server is the simplest way to implement a service, the resulting service can only be as fault tolerant as the processor executing that server. If this level of fault tolerance is unacceptable, then multiple servers that fail independently can be used. Usually, replicas of a single server are executed on separate processors of a distributed system, and protocols are used to coordinate client interactions with these replicas.
State machine
For the subsequent discussion a State Machine will be defined as the following tuple of values (See also Mealy machine and Moore Machine):
A set of States
A set of Inputs
A set of Outputs
A transition function (Input × State → State)
An output function (Input × State → Output)
A distinguished State called Start.
A State Machine begins at the State labeled Start. Each Input received is passed through the transition and output function to produce a new State and an Output. The State is held stable until a new Input is received, while the Output is communicated to the appropriate receiver.
This discussion requires a State Machine to be deterministic: multiple copies of the same State Machine begin in the Start state, and receiving the same Inputs in the same order will arrive at the same State having generated the same Outputs.
Typically, systems based on State Machine Replication voluntarily restrict their implementations to use finite-state machines to simplify error recovery.
Fault T
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https://en.wikipedia.org/wiki/Cryptographic%20log%20on
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Cryptographic log-on (CLO) is a process that uses Common Access Cards (CAC) and embedded Public Key Infrastructure (PKI) certificates to authenticate a user's identification to a workstation and network. It replaces the username and passwords for identifying and authenticating users. To log-on cryptographically to a CLO-enabled workstation, users simply insert their CAC into their workstation’s CAC reader and provide their Personal Identification Number (PIN).
The Navy/Marine Corps Intranet, among many other secure networks, uses CLO.
References
Computer access control
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https://en.wikipedia.org/wiki/Dead-beat%20control
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In discrete-time control theory, the dead-beat control problem consists of finding what input signal must be applied to a system in order to bring the output to the steady state in the smallest number of time steps.
For an Nth-order linear system it can be shown that this minimum number of steps will be at most N (depending on the initial condition), provided that the system is null controllable (that it can be brought to state zero by some input). The solution is to apply feedback such that all poles of the closed-loop transfer function are at the origin of the z-plane. This approach is straightforward for linear systems. However, when it comes to nonlinear systems, dead beat control is an open research problem.
Usage
The sole design parameter in deadbeat control is the sampling period. As the error goes to zero within N sampling periods, the settling time remains within the range of Nh, where h is the sampling parameter.
Also, the magnitude of the control signal increases significantly as the sampling period decreases. Thus, careful selection of the sampling period is crucial when employing this control method.
Finally, since the controller is based upon cancelling plant poles and zeros, these must be known precisely, otherwise the controller will not be deadbeat.
Transfer function of dead-beat controller
Consider that a plant has the transfer function
where
The transfer function of the corresponding dead-beat controller is
where d is the minimum necessary system delay for controller to be realizable. For example, systems with two poles must have at minimum 2 step delay from controller to output, so d = 2.
The closed-loop transfer function is
and has all poles at the origin. In general, a closed loop transfer function which has all of its poles at the origin is called a dead beat transfer function.
Notes
References
Kailath, Thomas: Linear Systems, Prentice Hall, 1980,
Warwick, Kevin: Adaptive dead beat control of stochastic systems, Internatio
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https://en.wikipedia.org/wiki/Crick%20Lecture
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The Francis Crick Medal and Lecture is a prize lecture of the Royal Society established in 2003 with an endowment from Sydney Brenner, the late Francis Crick's close friend and former colleague. It is delivered annually in biology, particularly the areas which Francis Crick worked (genetics, molecular biology and neurobiology), and also to theoretical work. The medal is also intended for young scientists, i.e. under 40, or at career stage corresponding to being under 40 should their career have been interrupted.
List of lectures
Laureates include:
2022 for making fundamental advances in the molecular, cellular and circuit bases of neuronal computation and for successfully linking these to animal decision behaviour
2021 Serena Nik-Zainal for enormous contributions to understanding the aetiology of cancers by her analyses of mutation signatures in cancer genomes, which is now being applied to cancer therapy
2020 Marta Zlatic for discovering how neural circuits generate behaviour by developing and disseminating definitive techniques, and by discovering fundamental principles governing circuit development and function
2019 Gregory Jefferis for his fundamental discoveries concerning the development and functional logic of sensory information processing
2018 Miratul Muqit in recognition of his research on cell signalling linked to neurodegeneration in Parkinson’s disease
2017 for transforming our understanding of meiotic recombination and of human population history.
2016 Madan Babu Mohan for his major and widespread contributions to computational biology
2015 Rob Klose for his research on how chromatin-based and epigenetic processes contribute to gene regulation
2014 Duncan Odom for his pioneering work in the field of comparative functional genomics
2013 Matthew Hurles on Mutations: great and small
2012 Sarah Teichmann on Finding patterns in genes and proteins: decoding the logic of molecular interactions
2011 Simon Boulton on Repairing the code
2010
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https://en.wikipedia.org/wiki/Ethyl%20pentanoate
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Ethyl pentanoate, also commonly known as ethyl valerate, is an organic compound used in flavors. It is an ester with the molecular formula C7H14O2. This colorless liquid is poorly soluble in water but miscible with organic solvents.
As is the case with most volatile esters, it has a pleasant aroma and taste. It is used as a food additive to impart a fruity flavor, particularly of apple.
References
Ethyl esters
Food additives
Flavors
Valerate esters
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https://en.wikipedia.org/wiki/Butyl%20butyrate
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Butyl butyrate, or butyl butanoate, is an organic compound that is an ester formed by the condensation of butyric acid and n-butanol. It is a clear, colorless liquid that is insoluble in water, but miscible with ethanol and diethyl ether. Its refractive index is 1.406 at 20 °C.
Aroma
Like other volatile esters, butyl butyrate has a pleasant aroma. It is used in the flavor industry to create sweet fruity flavors that are similar to that of pineapple. It occurs naturally in many kinds of fruit including apple, banana, berries, pear, plum, and strawberry.
Safety
It is a marine pollutant. It mildly irritates the eyes and skin.
References
Butyrate esters
Flavors
Butyl compounds
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https://en.wikipedia.org/wiki/Social%20organism
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Social organism is a sociological concept, or model, wherein a society or social structure is regarded as a "living organism". The various entities comprising a society, such as law, family, crime, etc., are examined as they interact with other entities of the society to meet its needs. Every entity of a society, or social organism, has a function in helping maintain the organism's stability and cohesiveness.
History
The model, or concept, of society-as-organism is traced by Walter M. Simon from Plato ('the organic theory of society'), and by George R. MacLay from Aristotle (384–322 BCE) through 19th-century and later thinkers, including the French philosopher and founder of sociology, Auguste Comte, the Scottish essayist, historian and philosopher Thomas Carlyle, the English philosopher and polymath Herbert Spencer, and the French sociologist Émile Durkheim.
According to Durkheim, the more specialized the function of an organism or society, the greater its development, and vice versa. The three core activities of a society are culture, politics, and economics. Societal health depends on the harmonious interworking of these three activities.
This concept was further developed beginning in 1904, over the next two decades, by the Austrian philosopher and social reformer Rudolf Steiner in his lectures, essays, and books on the Threefold Social Order. The "health" of a social organism can be thought of as a function of the interaction of culture, politics and rights, and economics, which in theory can be studied, modeled, and analyzed.
During his work on social order, Steiner developed his "Fundamental Social Law" of economic systems: "Most of all,... our times are suffering from the lack of any basic social understanding of how work can be incorporated into the social organism correctly, so that everything we do is truly performed for the sake of our fellow human beings. We can acquire this understanding only by learning to really insert our 'I' into the
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https://en.wikipedia.org/wiki/Calciphylaxis
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Calciphylaxis, also known as calcific uremic arteriolopathy (CUA) or “Grey Scale”, is a rare syndrome characterized by painful skin lesions. The pathogenesis of calciphylaxis is unclear but believed to involve calcification of the small blood vessels located within the fatty tissue and deeper layers of the skin, blood clots, and eventual death of skin cells due to lack of blood flow. It is seen mostly in people with end-stage kidney disease but can occur in the earlier stages of chronic kidney disease and rarely in people with normally functioning kidneys. Calciphylaxis is a rare but serious disease, believed to affect 1-4% of all dialysis patients. It results in chronic non-healing wounds and indicates poor prognosis, with typical life expectancy of less than one year.
Calciphylaxis is one type of extraskeletal calcification. Similar extraskeletal calcifications are observed in some people with high levels of calcium in the blood, including people with milk-alkali syndrome, sarcoidosis, primary hyperparathyroidism, and hypervitaminosis D. In rare cases, certain medications such as warfarin can also result in calciphylaxis.
Signs and symptoms
The first skin changes in calciphylaxis lesions are mottling of the skin and induration in a livedo reticularis pattern. As tissue thrombosis and infarction occurs, a black, leathery eschar in an ulcer with adherent black slough develops. Surrounding the ulcers is usually a plate-like area of indurated skin. These lesions are always extremely painful and most often occur on the lower extremities, abdomen, buttocks, and penis. Lesions are also commonly multiple and bilateral. Because the tissue has infarcted, wound healing seldom occurs, and ulcers are more likely to become secondarily infected. Many cases of calciphylaxis lead to systemic bacterial infection and death.
Calciphylaxis is characterized by the following histologic findings:
systemic medial calcification of the arteries, i.e. calcification of tunica media. Unli
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https://en.wikipedia.org/wiki/Prurigo%20nodularis
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Prurigo nodularis (PN), also known as nodular prurigo, is a skin disease characterised by pruritic (itchy) nodules which usually appear on the arms or legs. Patients often present with multiple excoriated lesions caused by scratching. PN is also known as Hyde prurigo nodularis, Picker's nodules, atypical nodular form of neurodermatitis circumscripta, lichen corneus obtusus.
Lichen simplex chronicus is a distinct clinical entity.
Signs and symptoms
Nodules are discrete, generally symmetric, hyperpigmented or purpuric, and firm. They are greater than 0.5 cm in both width and depth (as opposed to papules which are less than 0.5 cm). They can appear on any part of the body, but generally begin on the arms and legs.
Excoriated lesions are often flat, umbilicated, or have a crusted top.
Nodules may appear to begin in the hair follicles.
Nodule pattern may be follicular.
In true prurigo nodularis, a nodule forms before itching begins. Typically, these nodules are extremely pruritic and are alleviated only by steroids.
Causes
The cause of prurigo nodularis is unknown, although other conditions may induce PN. PN has been linked to Becker's nevus, linear IgA disease, an autoimmune condition, liver disease and T cells. Systemic pruritus has been linked to cholestasis, thyroid disease, polycythaemia rubra vera, uraemia, Hodgkins disease, HIV and other immunodeficiency diseases. Internal malignancies, liver failure, kidney failure, and psychiatric illnesses have been considered to induce PN, although more recent research has refuted a psychiatric cause for PN. Patients report an ongoing battle to distinguish themselves from those with psychiatric disorders, such as delusions of parasitosis and other psychiatric conditions.
Pathophysiology
Chronic and repetitive scratching, picking, or rubbing of the nodules may result in permanent changes to the skin, including nodular lichenification, hyperkeratosis, hyperpigmentation, and skin thickening. Unhealed, excoriated lesion
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https://en.wikipedia.org/wiki/Marine%20ecosystem
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Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply and 90% of habitable space on Earth. Seawater has an average salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems. Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides. Other near-shore (neritic) zones can include mudflats, seagrass meadows, mangroves, rocky intertidal systems, salt marshes, coral reefs, lagoons. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web. Marine ecosystems are characterized by the biological community of organisms that they are associated with and their physical environment. Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks.
Marine ecosystems are important sources of ecosystem services and food and jobs for significant portions of the global population. Human uses of marine ecosystems and pollution in marine ecosystems are significantly threats to the stability of these ecosystems. Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), marine pollution, climate change, and building on coastal areas. Moreover, much of the carbon dioxide causing global warming and heat captured by global warming are absorbed by the ocean, ocean chemistry is changing through
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https://en.wikipedia.org/wiki/Multiple%20description%20coding
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Multiple description coding (MDC) in computing is a coding technique that fragments a single media stream into n substreams (n ≥ 2) referred to as descriptions. The packets of each description are routed over multiple, (partially) disjoint paths. In order to decode the media stream, any description can be used, however, the quality improves with the number of descriptions received in parallel. The idea of MDC is to provide error resilience to media streams. Since an arbitrary subset of descriptions can be used to decode the original stream, network congestion or packet loss — which are common in best-effort networks such as the Internet — will not interrupt the stream but only cause a (temporary) loss of quality. The quality of a stream can be expected to be roughly proportional to data rate sustained by the receiver.
MDC is a form of data partitioning, thus comparable to layered coding as it is used in MPEG-2 and MPEG-4. Yet, in contrast to MDC, layered coding mechanisms generate a base layer and n enhancement layers. The base layer is necessary for the media stream to be decoded, enhancement layers are applied to improve stream quality. However, the first enhancement layer depends on the base layer and each enhancement layer n + 1 depends on its subordinate layer n, thus can only be applied if n was already applied. Hence, media streams using the layered approach are interrupted whenever the base layer is missing and, as a consequence, the data of the respective enhancement layers is rendered useless. The same applies for missing enhancement layers. In general, this implies that in lossy networks the quality of a media stream is not proportional to the amount of correctly received data.
Besides increased fault tolerance, MDC allows for rate-adaptive streaming: Content providers send all descriptions of a stream without paying attention to the download limitations of clients. Receivers that cannot sustain the data rate only subscribe to a subset of these streams,
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https://en.wikipedia.org/wiki/Subaudible%20tone
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A subaudible tone is a tone that is used to trigger an automated event at a radio station. A subaudible tone is audible; however, it is usually at a low level that is not noticeable to the average listener at normal volumes. It is a form of in-band signaling.
Overview
These tones are included in the audible main portion of audio in the case of satellite; on tape, these often are filtered. Normally, subaudible tones are at one of the following frequencies: 25, 35, 50, 75 hertz (Hz), or combinations of those frequencies. Until computerized radio automation became inexpensive and common, 25 and 35 Hz were used either in the audio stream or, in the case of tape cartridges used in radio broadcasting (better known as "carts"), on a special track on the tape to indicate to a radio station's automation system that it was time to trigger another event.
With the advent of computers and digital satellite, these tones are relegated to triggering commercial announcements and legal IDs on a dwindling number of radio networks, as tones in the audio have been supplanted by external data channels sent independent of audio on digital satellite feeds for radio. These trigger relay closure terminals on the satellite receiver itself (Starguide being a prominent system).
Use for filmstrips
Subaudible tones have also been used by later filmstrip projectors to advance to the next frame in a filmstrip presentation. Previously, the phonographic record or audio cassette accompanying a filmstrip to provide its soundtrack would have an audible tone to signal the person operating the projector to advance the film to the next frame. But automatic filmstrip projectors were introduced in the 1970s (that had an integrated phonograph or cassette player) that would read a subaudible tone of 50 Hz recorded on the soundtrack to automatically trigger the projector to advance to the next frame.
Most of the cassettes accompanying filmstrips from the 1970s and 80s would have one side of the med
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https://en.wikipedia.org/wiki/GRANK
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GRANK, or Global Rank is a ranking of the rarity of a species, and is a useful tool in determining conservation needs.
Global Ranks are derived from a consensus of various conservation data centres, natural heritage programmes, scientific experts and NatureServe.
They are based on the total number of known, extant populations worldwide, and to what degree they are threatened by destruction. Criteria also include securely protected populations, size of populations, and the ability of the species to persist.
G1 — Critically Imperiled At very high risk of extinction or collapse due to very restricted range, very few populations or occurrences, very steep declines, very severe threats, or other factors.
G2 — Imperiled At high risk of extinction or collapse due to restricted range, few populations or occurrences, steep declines, severe threats, or other factors.
G3 — Vulnerable At moderate risk of extinction or collapse due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors.
G4 — Apparently Secure At fairly low risk of extinction or collapse due to an extensive range and/or many populations or occurrences, but with possible cause for some concern as a result of local recent declines, threats, or other factors.
G5 — Secure At very low risk or extinction or collapse due to a very extensive range, abundant populations or occurrences, and little to no concern from declines or threats.
GH — Possibly Extinct (species) or Possibly Collapsed (ecosystems/communities) Known from only historical occurrences but still some hope of rediscovery. Examples of evidence include (1) that a species has not been documented in approximately 20-40 years despite some searching and/or some evidence of significant habitat loss or degradation; (2) that a species or ecosystem has been searched for unsuccessfully, but not thoroughly enough to presume that it is extinct or collapsed throughout its range.
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https://en.wikipedia.org/wiki/NRANK
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NRANK, or National Rank, is a ranking of the rarity of a species within a nation. Each nation can assign their own NRANK based on information from conservation data centres, natural heritage programmes, and expert scientists.
Taxonomy (biology)
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https://en.wikipedia.org/wiki/Indian%20Railway%20Service%20of%20Electrical%20Engineers
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The Indian Railway Service of Electrical Engineers (IRSEE) is a prestigious group A central engineering services of the Indian railways. The officers of this service are responsible for managing the Electrical Engineering organisation of the Indian Railways.
The Indian railways have technical and non-technical departments for its operation and management which form the base structure on which the railways function. Technical departments include civil, electrical and mechanical engineering, signaling and telecom, and several others dealing with similar disciplines, control of operation and movement is done by traffic services(IRTS) while the non-technical departments include general services such as accounts, personnel management, Railway protection Force (RPF) or security, among others. Each department has staff at various levels. The highest are the Group A officers, while the lowest in rank are the Group D staff members.
IRSEE falls under the category of Group "A" officers.
Recruitment
The recruitment to the IRSEE cadre is done through the Indian Engineering Services Exam (ESE) ,conducted by the Union Public Service Commission (UPSC) of India. The UPSC is responsible for recruiting middle and top-level bureaucrats for the Government of India. The Present IRSEE Cadre Strength is around 2000 .
Role and function
The officers of this cadre are responsible to maintain the assets of the Electrical Department in Indian railways. Mainly divided in following branches General Service(G), Traction Operation(TrO), Traction distribution(TrD), Traction Rolling Stock(TRS). Traction Rolling Stock includes production and maintenance of Electric Locomotives, Electrical Multiple Units(EMUs) and Main Line EMUs(MEMUs). Traction Distribution includes the maintenance of substations(PS) and Over Head Equipments(OHE) involved in movement of Rolling Stock. These assets are monitored and controlled by SCADA system.
History
The IRSEE was created as an organised service after the nationa
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https://en.wikipedia.org/wiki/Indian%20Railway%20Service%20of%20Signal%20Engineers
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The Indian Railway Service of Signal Engineers (IRSSE) is a central engineering services group A cadre of the Indian railways. The officers of this service are responsible for managing the Signal and Telecommunications Engineering Organization of the Indian Railways.
Recruitment
The incumbents who were Graduates in Engineering used to get selected by the Union Public Services Commission, the apex gazetted recruitment body of the Government of India. In 2020 Railways separated itself from Engineering Services Exam (ESE) and made Indian Railway Management Services (IRMS). Earlier the recruitment used to be through UPSC Engineering Services Exam for Engineers but now after 2 years halt it's through UPSC Civil Services Exam from 2022 ; an all India written test followed by interview for selected candidates. Earlier Top rankers of Electronics and Telecommunication Engineering only used to get the chance to join IRSSE cadre, but now it has become General Cadre or Cadre for all Civil Services aspirants. They are inducted into the service after One and Half years of rigorous training at Indian Railways Institute of Signal Engineering and Telecommunication (IRISET) at Secunderabad and National Academy of Indian Railways (Formerly Railway Staff College) at Baroda and different parts of India.
The Indian Railway Management Services is merged into Civil Services in 2022 which now on will be conducted by the Union Public Service Commission (UPSC) of India. The UPSC is responsible for recruiting middle and top-level bureaucrats for the Government of India.
Role and function
Functional Role : The service abbreviated as IRSSE has the job of managing the vast Signalling and Telecommunication (S&T) infrastructure of the Indian Railways. This basically is techno-managerial in nature. Signalling principles and operating rules.
The Signalling is a function essential for Safe Train operations and Maximizing the utilization of fixed and moving assets (Train rakes, locos, Track, Ov
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https://en.wikipedia.org/wiki/Indian%20Railway%20Service%20of%20Engineers
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The Indian Railways Service of Engineers (IRSE) is one of the oldest group 'A' central engineering services recruited through the engineering services examination of the Union Public Service Commission. The officers of this service are responsible for administering the Civil Engineering organisation of the Indian Railways
Recruitment
The recruitment to the IRSE is done through the Engineering Services Examination exam. The selected candidates of civil engineering join IRSE and are finally inducted into the railways after one and a half years of training to manage the fixed infrastructure assets of Indian Railways.
The selection exam is conducted by the Union Public Service Commission (UPSC) of India. The UPSC is responsible for recruiting middle and top-level bureaucrats for the Government of India.
Role and function
The Civil engineering department of Indian Railways is managed by IRSE cadre which is one of the oldest services of India. These officers are responsible for the maintenance of all fixed assets of Indian railways, i.e. Track, Bridges, Buildings, Roads, Water supply, land etc. Those fixed assets are 45% of the total assets of Indian Railways. In addition to maintenance of existing assets, IRSE officers are responsible for the construction of new assets such as new lines, gauge conversion, doubling and other expansion and developmental works in Railways. They are also responsible for the safety and punctuality of Indian Railways.
Recruitment to service is done on the basis of "Engineering Services" examination conducted by UPSC every year in January. The number of new recruits varies each year. Presently, intake is about 45 probationers per year.
An aspirant is not necessarily a Civil Engineering graduate. Indeed he needs to appear for the Civil Engineering stream in Engineering services exam and become qualified.
After Recruitment, the probationer is given 18 months' intensive training in various Railways establishments under the guidance of Indi
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https://en.wikipedia.org/wiki/Indian%20Railway%20Stores%20Service
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The Indian Railway Stores Service (IRSS) is one of the Group A central engineering services of the Government of India. The officers of this service are procurement and logistics specialists, contract managers on the Indian Railways, providers of logistics for the transportation of material from and within various railways as well as the planners and maintainers of the intelligent warehousing with automated storage and retrieval systems on the Indian Railways.
The IRSS officers undergo training at National Academy of Indian Railways (NAIR) for a period of 18 months which includes two months certification course at IIM Khozikhode and a foreign training.
Recruitment & Job responsibility of IRSS
IRSS Officers man the senior posts of stores department and also general administrative posts of Indian Railways. The members of this group A service are recruited through the Engineering Services Examination conducted annually by the Union Public Service Commission The basic qualification for appearing in this examination is a degree in engineering and all the members belonging to this service are engineers. The Department of Personnel and Training DOPT defines it as a Technical Service. The total sanctioned strength of cadre is 542. The young officer after being intensively trained for 18 months under the guidance of National Academy of Indian Railways is posted as AMM in junior scale. The officer can rise up to chairman railway board (ex officio principal secretary to GOI). In normal course all officers rise up to the level of Additional Secretary to GOI. At the level of Railway Board the service is headed by Member (Material Management), ex-officio secretary to GOI. IRSS cadre not only caters to stores departments but contribute significantly to the general administration of Indian Railways in particular and the Government of India in general. The various ex-cadre posts held by officers of service are Chairman of Railway Board, General Manager, Divisional Railway M
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https://en.wikipedia.org/wiki/Active%20object
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The active object design pattern decouples method execution from method invocation for objects that each reside in their own thread of control. The goal is to introduce concurrency, by using asynchronous method invocation and a scheduler for handling requests.
The pattern consists of six elements:
A proxy, which provides an interface towards clients with publicly accessible methods.
An interface which defines the method request on an active object.
A list of pending requests from clients.
A scheduler, which decides which request to execute next.
The implementation of the active object method.
A callback or variable for the client to receive the result.
Example
Java
An example of active object pattern in Java.
Firstly we can see a standard class that provides two methods that set a double to be a certain value. This class does NOT conform to the active object pattern.
class MyClass {
private double val = 0.0;
void doSomething() {
val = 1.0;
}
void doSomethingElse() {
val = 2.0;
}
}
The class is dangerous in a multithreading scenario because both methods can be called simultaneously, so the value of val (which is not atomic—it's updated in multiple steps) could be undefined—a classic race condition. You can, of course, use synchronization to solve this problem, which in this trivial case is easy. But once the class becomes realistically complex, synchronization can become very difficult.
To rewrite this class as an active object, you could do the following:
class MyActiveObject {
private double val = 0.0;
private BlockingQueue<Runnable> dispatchQueue = new LinkedBlockingQueue<Runnable>();
public MyActiveObject() {
new Thread (new Runnable() {
@Override
public void run() {
try {
while (true) {
dispatchQueue.take().run();
}
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https://en.wikipedia.org/wiki/Gottfrid%20Svartholm
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Per Gottfrid Svartholm Warg (born 17 October 1984), alias anakata, is a Swedish computer specialist, known as the former co-owner of the web hosting company PRQ and co-founder of the BitTorrent site The Pirate Bay together with Fredrik Neij and Peter Sunde.
Parts of an interview with Svartholm commenting on the May 2006 police raid of The Pirate Bay are featured in Good Copy Bad Copy and Steal This Film. He is a main focus of the documentary TPB AFK.
In May 2013, WikiLeaks said Svartholm Warg had worked with the organization for the 2010 release of Collateral Murder, the helicopter cockpit gunsight video of a July 2007 airstrike by U.S. forces in Baghdad. According to WikiLeaks, Svartholm served as technical consultant and managed infrastructure critical to the organization. He was also listed as part of the “decryption and transmission team” and credited for “networking.” Svartholm was one of several Pirate Bay associates who did work for other Wikileaks endeavors. One of Svartholm's companies had previously hosted WikiLeaks' computers.
On 27 November 2013, he was extradited to Denmark, where he was charged with infiltrating the Danish social security database, driver's licence database, and the shared IT system used in the Schengen zone. Awaiting his court trial, he was being held in solitary confinement. A court trial ended on 31 October 2014, and he was found guilty by the jury and sentenced to three and a half years in prison. The sentence was appealed immediately, but the judges, fearing that he might try to evade his sentence, ordered that he be held in confinement until the appeal court trial date.
After spending three years in different prisons in both Sweden and Denmark, he was eventually released on 29 September 2015. According to his mother, he expressed a desire ‘to get back to his developmental work within IT’ upon his release.
Americas Dumbest Soldiers and meeting Fredrik Neij
Svartholm Warg started the website Americas Dumbest Soldiers which li
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https://en.wikipedia.org/wiki/PRQ
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PRQ is a Swedish Internet service provider and web hosting company created in 2004.
Ownership
Based in Stockholm, PRQ was created by Gottfrid Svartholm and Fredrik Neij, two founders of The Pirate Bay.
Business model
Part of PRQ's business model is to host any customers, regardless of how odd or controversial they may be. The New York Times wrote in 2008 that "The Pirate Bay guys have made a sport out of taunting all forms of authority, including the Swedish police, and PRQ has gone out of its way to be a host to sites that other companies would not touch." The PRQ service has been described as "highly secure, no-questions-asked hosting services". The company holds almost no information about its clientele and is maintaining few if any of its own logs, according to a 2008 news report. Fredrik Neij and Gottfrid Svartholm are said to have amassed "considerable expertise in withstanding legal attacks". Svartholm is quoted to have said, "We do employ our own legal staff. We are used to this sort of situation" in a telephone interview. Due to hosting The Pirate Bay, PRQ was the target of a police raid.
Criticism
The co-founders have been criticized for hosting controversial websites, including web pages that promote paedophilia, such as the North American Man/Boy Love Association (NAMBLA), a paedophile and pederasty advocacy organization. Local authorities and anti-paedophilia activists in Sweden have failed to persuade PRQ to close the sites. The pair defended their decision, citing freedom of speech.
The co-owners were also criticized for creating and hosting AMERICASDUMBESTSOLDIERS.COM, a website identifying deceased military personnel that invited visitors to rank how "dumb" the soldiers were based on the manner in which they died.
Other criticism originates from the hosting of BitTorrent website The Pirate Bay, WikiLeaks, and the French far-right blog Fdesouche.
Legal issues
On 1 October 2012, PRQ was raided and a number of sites which they provided hosting
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https://en.wikipedia.org/wiki/ArchNet
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Archnet is a collaborative digital humanities project focused on Islamic architecture and the built environment of Muslim societies. Conceptualized in 1998 and originally developed at the MIT School of Architecture and Planning in co-operation with the Aga Khan Trust for Culture. It has been maintained by the Aga Khan Documentation Center at MIT and the Aga Khan Trust for Culture since 2011.
Archnet is an open access resource providing all users with resources on architecture, urban design and development in the Muslim world.
History and Conceptualization
The Aga Khan Trust for Culture (AKTC) is an agency of the Aga Khan Development Network (AKDN). Through various programmes, partnerships, and initiatives, the AKTC seeks to improve the built environment in Asia and Africa where there is a significant Muslim presence. Archnet complements the work of the Trust by making its resources digitally accessible to individuals worldwide.
Archnet was conceptualized in 1998 during a series of discussions between Aga Khan IV; the President of the Massachusetts Institute of Technology (MIT) Charles Vest; and the Dean of MIT’s School of Architecture and Planning, William J. Mitchell. The foundations of Archnet were predicated on remarks made by Aga Khan in Istanbul in 1983, about his desire to make available the extensive dossiers resulting from the nominations for the Aga Khan Award for Architecture (AKAA) for the purpose of “[assisting] those institutions where the professionals of the future are trained.”
The purpose of the website is to create a viable platform upon which knowledge pertaining to the field of architecture can be shared. Archnet aims to expand the general intellectual frame of reference to transcend the barriers of geography, socio-economic status and religion, and to foster a spirit of collaboration and open dialogue. Archnet therefore manifests many of the Aga Khan’s values and principles regarding not only rural and urban development but also pluralism a
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https://en.wikipedia.org/wiki/Artin%20billiard
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In mathematics and physics, the Artin billiard is a type of a dynamical billiard first studied by Emil Artin in 1924. It describes the geodesic motion of a free particle on the non-compact Riemann surface where is the upper half-plane endowed with the Poincaré metric and is the modular group. It can be viewed as the motion on the fundamental domain of the modular group with the sides identified.
The system is notable in that it is an exactly solvable system that is strongly chaotic: it is not only ergodic, but is also strong mixing. As such, it is an example of an Anosov flow. Artin's paper used symbolic dynamics for analysis of the system.
The quantum mechanical version of Artin's billiard is also exactly solvable. The eigenvalue spectrum consists of a bound state and a continuous spectrum above the energy . The wave functions are given by Bessel functions.
Exposition
The motion studied is that of a free particle sliding frictionlessly, namely, one having the Hamiltonian
where m is the mass of the particle, are the coordinates on the manifold, are the conjugate momenta:
and
is the metric tensor on the manifold. Because this is the free-particle Hamiltonian, the solution to the Hamilton-Jacobi equations of motion are simply given by the geodesics on the manifold.
In the case of the Artin billiards, the metric is given by the canonical Poincaré metric
on the upper half-plane. The non-compact Riemann surface is a symmetric space, and is defined as the quotient of the upper half-plane modulo the action of the elements of acting as Möbius transformations. The set
is a fundamental domain for this action.
The manifold has, of course, one cusp. This is the same manifold, when taken as the complex manifold, that is the space on which elliptic curves and modular functions are studied.
References
E. Artin, "Ein mechanisches System mit quasi-ergodischen Bahnen", Abh. Math. Sem. d. Hamburgischen Universität, 3 (1924) pp170-175.
Chaotic maps
Ergodic
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https://en.wikipedia.org/wiki/Chorobates
|
The chorobates, described by Vitruvius in Book VIII of the De architectura, was used to measure horizontal planes and was especially important in the construction of aqueducts.
Similar to modern spirit levels, the chorobates consisted of a beam of wood 6 m in length held by two supporting legs and equipped with two plumb lines at each end. The legs were joined to the beam by two diagonal rods with carved notches. If the notches corresponding to the plumb lines matched on both sides, it showed that the beam was level. On top of the beam, a groove or channel was carved. If the condition was too windy for the plumb bobs to work effectively, the surveyor could pour water into the groove and measure the plane by checking the water level.
See also
Groma
Dioptra
Chorography
Odometer
References
M. J. T. Lewis. Surveying Instruments of Greece and Rome. Cambridge University Press. . 2001. p 31.
External links
Surveying and engineering in Ancient Rome
Chorobates described
Measuring instruments
Surveying
Ancient Greece
Ancient Roman architecture
|
https://en.wikipedia.org/wiki/ICMP%20tunnel
|
An ICMP tunnel establishes a covert connection between two remote computers (a client and proxy), using ICMP echo requests and reply packets. An example of this technique is tunneling complete TCP traffic over ping requests and replies.
Technical details
ICMP tunneling works by injecting arbitrary data into an echo packet sent to a remote computer. The remote computer replies in the same manner, injecting an answer into another ICMP packet and sending it back. The client performs all communication using ICMP echo request packets, while the proxy uses echo reply packets.
In theory, it is possible to have the proxy use echo request packets (which makes implementation much easier), but these packets are not necessarily forwarded to the client, as the client could be behind a translated address (NAT). This bidirectional data flow can be abstracted with an ordinary serial line.
ICMP tunneling is possible because RFC 792, which defines the structure of ICMP packets, allows for an arbitrary data length for any type 0 (echo reply) or 8 (echo message) ICMP packets.
Uses
ICMP tunneling can be used to bypass firewalls rules through obfuscation of the actual traffic. Depending on the implementation of the ICMP tunneling software, this type of connection can also be categorized as an encrypted communication channel between two computers. Without proper deep packet inspection or log review, network administrators will not be able to detect this type of traffic through their network.
Mitigation
One way to prevent this type of tunneling is to block ICMP traffic, at the cost of losing some network functionality that people usually take for granted (e.g. it might take tens of seconds to determine that a peer is offline, rather than almost instantaneously). Another method for mitigating this type of attack is to only allow fixed sized ICMP packets through firewalls, which can impede or eliminate this type of behavior.
ICMP-tunnels are sometimes used to circumvent firewalls th
|
https://en.wikipedia.org/wiki/Voigt%20effect
|
The Voigt effect is a magneto-optical phenomenon which rotates and elliptizes linearly polarised light sent into an optically active medium. Unlike many other magneto-optical effects such as the Kerr or Faraday effect which are linearly proportional to the magnetization (or to the applied magnetic field for a non magnetized material), the Voigt effect is proportional to the square of the magnetization (or square of the magnetic field) and can be seen experimentally at normal incidence. There are several denominations for this effect in the literature: the Cotton–Mouton effect (in reference to French scientists Aimé Cotton and Henri Mouton), the Voigt effect (in reference to the German scientist Woldemar Voigt), and magnetic-linear birefringence. This last denomination is closer in the physical sense, where the Voigt effect is a magnetic birefringence of the material with an index of refraction parallel () and perpendicular ) to the magnetization vector or to the applied magnetic field.
For an electromagnetic incident wave linearly polarized and an in-plane polarized sample , the expression of the rotation in reflection geometry is is:
and in the transmission geometry:
where is the difference of refraction indices depending on the Voigt parameter (same as for the Kerr effect), the material refraction indices and the parameter responsible of the Voigt effect and so proportional to the or in the case of a paramagnetic material.
Detailed calculation and an illustration are given in sections below.
Theory
As with the other magneto-optical effects, the theory is developed in a standard way with the use of an effective dielectric tensor from which one calculates systems eigenvalues and eigenvectors. As usual, from this tensor, magneto-optical phenomena are described mainly by the off-diagonal elements.
Here, one considers an incident polarisation propagating in the z direction: the electric field and a homogenously in-plane magnetized sample where is cou
|
https://en.wikipedia.org/wiki/Hadamard%27s%20dynamical%20system
|
In physics and mathematics, the Hadamard dynamical system (also called Hadamard's billiard or the Hadamard–Gutzwiller model) is a chaotic dynamical system, a type of dynamical billiards. Introduced by Jacques Hadamard in 1898, and studied by Martin Gutzwiller in the 1980s, it is the first dynamical system to be proven chaotic.
The system considers the motion of a free (frictionless) particle on the Bolza surface, i.e, a two-dimensional surface of genus two (a donut with two holes) and constant negative curvature; this is a compact Riemann surface. Hadamard was able to show that every particle trajectory moves away from every other: that all trajectories have a positive Lyapunov exponent.
Frank Steiner argues that Hadamard's study should be considered to be the first-ever examination of a chaotic dynamical system, and that Hadamard should be considered the first discoverer of chaos. He points out that the study was widely disseminated, and considers the impact of the ideas on the thinking of Albert Einstein and Ernst Mach.
The system is particularly important in that in 1963, Yakov Sinai, in studying Sinai's billiards as a model of the classical ensemble of a Boltzmann–Gibbs gas, was able to show that the motion of the atoms in the gas follow the trajectories in the Hadamard dynamical system.
Exposition
The motion studied is that of a free particle sliding frictionlessly on the surface, namely, one having the Hamiltonian
where m is the mass of the particle, , are the coordinates on the manifold, are the conjugate momenta:
and
is the metric tensor on the manifold. Because this is the free-particle Hamiltonian, the solution to the Hamilton–Jacobi equations of motion are simply given by the geodesics on the manifold.
Hadamard was able to show that all geodesics are unstable, in that they all diverge exponentially from one another, as with positive Lyapunov exponent
with E the energy of a trajectory, and being the constant negative curvature of the surface.
|
https://en.wikipedia.org/wiki/Full%20state%20feedback
|
Full state feedback (FSF), or pole placement, is a method employed in feedback control system theory to place the closed-loop poles of a plant in pre-determined locations in the s-plane. Placing poles is desirable because the location of the poles corresponds directly to the eigenvalues of the system, which control the characteristics of the response of the system. The system must be considered controllable in order to implement this method.
Principle
If the closed-loop dynamics can be represented by the state space equation (see State space (controls))
with output equation
then the poles of the system transfer function are the roots of the characteristic equation given by
Full state feedback is utilized by commanding the input vector . Consider an input proportional (in the matrix sense) to the state vector,
.
Substituting into the state space equations above, we have
The poles of the FSF system are given by the characteristic equation of the matrix , . Comparing the terms of this equation with those of the desired characteristic equation yields the values of the feedback matrix which force the closed-loop eigenvalues to the pole locations specified by the desired characteristic equation.
Example of FSF
Consider a system given by the following state space equations:
The uncontrolled system has open-loop poles at and . These poles are the eigenvalues of the matrix and they are the roots of . Suppose, for considerations of the response, we wish the controlled system eigenvalues to be located at and , which are not the poles we currently have. The desired characteristic equation is then , from .
Following the procedure given above, the FSF controlled system characteristic equation is
where
Upon setting this characteristic equation equal to the desired characteristic equation, we find
.
Therefore, setting forces the closed-loop poles to the desired locations, affecting the response as desired.
This only works for Single-Input systems. Mult
|
https://en.wikipedia.org/wiki/Drive%20mapping
|
Drive mapping is how MS-DOS and Microsoft Windows associate a local drive letter (A through Z) with a shared storage area to another computer (often referred as a File Server) over a network. After a drive has been mapped, a software application on a client's computer can read and write files from the shared storage area by accessing that drive, just as if that drive represented a local physical hard disk drive.
Drive mapping
Mapped drives are hard drives (even if located on a virtual or cloud computing system, or network drives) which are always represented by names, letter(s), or number(s) and they are often followed by additional strings of data, directory tree branches, or alternate level(s) separated by a "\" symbol. Drive mapping is used to locate directories, files or objects, and programs or apps, and is needed by end users, administrators, and various other operators or groups.
Mapped drives are usually assigned a letter of the alphabet after the first few taken, such as A:\, B:\ (both of which were historically removable flexible magnetic media drives), C:\ (usually the first or only installed hard disk), and D:\ (which was often an optical drive unit). Then, with the drive and/or directory (letters, symbols, numbers, names) mapped, they can be entered into the necessary address bar/location(s) and displayed as in the following:
Example 1:
C:\level\next level\following level
or
C:\BOI60471CL\Shared Documents\Multi-Media Dept
The preceding location may reach something like a company's multi-media department's database, which logically is represented with the entire string "C:\BDB60471CL\Shared Documents\Multi-Media Dept".
Mapping a drive can be complicated for a complex system. Network mapped drives (on LANs or WANs) are available only when the host computer (File Server) is also available (i.e. online): it is a requirement for use of drives on a host. All data on various mapped drives will have certain permissions set (most newer systems) and the
|
https://en.wikipedia.org/wiki/Acarinarium
|
An acarinarium is a specialized anatomical structure which is evolved to facilitate the retention of mites on the body of an organism, typically a bee or a wasp. The term was introduced by Walter Karl Johann Roepke.
Evolution
The acarinarium has evolved to enhance the mutualistic relationship between the mites and the host organism. There are numerous cases where mites are phoretic on organisms that benefit from the mites' presence; cases where the host's body has changed over evolutionary time to accommodate the mites are far less common. The best-known examples are among the Apocritan Hymenoptera, in which the hosts are typically nest-making species, and it appears that the mites feed on fungi in the host nests (thus keeping away the fungi from host's offspring or their provisions), or possibly other parasites or mites whose presence in the nest is detrimental to the hosts. It is especially telling that nearly all the examples involve only the females of the host species, as it is the females that build and provision the nests. Fossil evidence of halictid bees with an acarinarium is found in the early Miocene extinct genus Oligochlora from Dominican amber deposits on Hispaniola.
The presence or absence of this structure has been used as a taxonomic character.
Variations
Several examples can be found among the bees, and in most such cases, only the females possess acarinaria:
Various forms of acarinaria have evolved within different lineages of carpenter bees, in the Old World subgenera Koptortosoma and Mesotrichia - in some cases, the entire anterior portion of the metasoma is hollowed out into an enormous internal chamber, entered through a small opening on the face of the first metasomal tergite, in which the mites can travel. Some species in these groups also have supplementary acarinaria on the mesosoma in addition to the metasomal chamber.
The augochlorine halictid genus Thectochlora is characterized by a dense brush of hairs just in front of the anter
|
https://en.wikipedia.org/wiki/Do%21%20Run%20Run
|
Do! Run Run, also known as Super Pierrot (スーパーピエロ Sūpā Piero), is the fourth and final incarnation of Mr. Do!, the Universal video game mascot. Returning to his Mr. Do! roots, the clown has a bouncing powerball with which to hurl at monsters. Mr. Do runs along the playfield picking up dots and leaving a line behind him, which the player is encouraged to create closed off sections with. Precariously balanced log traps can be rolled downslope, crushing enemies. The resulting game is something of a cross between Mr. Do!, Congo Bongo, Pac-Man, and Qix.
Gameplay
The goal of Do! Run Run is to rack up points while completing screens. A screen is completed whenever all the fruits/dots are eaten, or when all of the regular monsters (not Alpha-monsters or their sidekicks) are defeated. Using the rope that follows Mr. Do to inscribe dots will convert them into cherries, a familiar fruit for Mr. Do to collect. Cherries are worth more points than dots, and eating them restores the powerball more quickly than eating dots would. Each time Mr. Do inscribes fruit, they progress to a higher tier, dots become cherries, cherries become apples, apples become lemons and lemons become pineapples. Eating a dot awards 10 points and 1/16 of a powerball recharge; eating a pineapple is worth 160 points and 1/4 of a powerball recharge.
Players are additionally encouraged to inscribe sections of the playfield by the letters E, X, T, R, A, a constant feature of the Mr. Do! games. Randomly, one of the inscribed fruits will turn into a flashing letter spot, corresponding with the movement of the Alpha-Monster at the top of the screen. If Mr. Do! runs over this spot, the monster sporting that letter will release from the top of the screen with three blue henchmen (which resemble the three ghost-like monsters from the original Mr. Do!, and chase after Mr. Do. Defeating the Alpha-monster will lock in that letter, and once all 5 letters are earned, the player earns an extra life (as well as pro
|
https://en.wikipedia.org/wiki/SNADS
|
SNADS or Systems Network Architecture Distribution Services is an "asynchronous
distribution service that can store data for delayed delivery."
SNADS uses SNA data links to allow messages and objects to be sent from system to system using the APPC protocol. It is a very robust service: once an object has been accepted by SNADS it will get to its destination. If the communication link is unavailable (down), the transmission will be held on the sending system until the link is available, at which time it is sent. If the transmission is interrupted, it will be resumed or re-sent once the communication problem is resolved.
SNADS is available on several IBM platforms, including IBM i, the AS/400 or System/38. Microsoft Exchange Server 5.5 Enterprise Edition includes a gateway called SNA Distribution Services (SNADS) Connector for communication with SNADS networks.
References
External links
SNADS documentation on ibm.com
See also
Systems Network Architecture
Systems Network Architecture
|
https://en.wikipedia.org/wiki/French%20Academy%20of%20Technologies
|
The National Academy of Technologies of France (Académie des technologies) is a learned society, founded in 2000, with an emphasis on technology, and the newest of French academies. In 2007 it acquired the status of établissement public, which enforces its public role.
Its stated missions are as follows:
Help to better exploit technologies in service of mankind
Provide clarity on emerging technologies
Contribute to public discussion of the risks and benefits of technologies
Contribute to professional and technological education
Interest the young and their parents in technologies and new careers
Raise public interest and comprehension in technologies
In 2021 the academy had approximately 350 active members, including emeritus and foreign members. It is organized into a number of commissions, committees, and work groups on subjects including information technology, ethics, energy and the environment, transport, simulation, defense, etc.
See also
French Academy of Sciences
External links
National Academy of Technologies of France
France
National academies of engineering
|
https://en.wikipedia.org/wiki/Unbundled%20network%20element
|
Unbundled network elements (UNEs) are a requirement mandated by the United States Telecommunications Act of 1996. They are the parts of the telecommunications network that the incumbent local exchange carriers (ILECs) are required to offer on an unbundled basis. Together, these parts make up a local loop that connects to a digital subscriber line access multiplexer (DSLAM), a voice switch or both. The loop allows non-facilities-based telecommunications providers to deliver service without having to lay network infrastructure such as copper wire, optical fiber, and coaxial cable.
UNE-Platform
A UNE-Platform (or UNE-P) is a combination of UNEs that allow end-to-end service delivery without any facilities. Despite not involving any CLEC facilities, a UNE-P still requires facilities-based certification from the Public Utilities Commission to deliver services.
Availability
In Telecommunications Act of 1996 sections 251(c)(3), incumbent local exchange carriers (LECs) are required to lease certain parts of their network specified by the FCC or by state PUCs. According to section 252(d)(1), these network elements must be provided on an unbundled basis at cost-based rates.
FCC orders
In the UNE Remand Order issued on November 5, 1999, the FCC specified the UNE to which a competitor must be provided access: "the 'loops' that connect the switches to end users, including high-capacity loops; the switches (with some exceptions), the transport facilities between switches and other networks, and the software needed to operate the telephone network".
In the Line Sharing Orders (Line Sharing Order, 14 FCC Rcd at 20951), the LECs are required to unbundle the high-frequency portion of the loop of DSL.
However, both the UNE Remand Order and the Line Sharing Orders were remanded by the D.C. Circuit Court of Appeals in United States Telecom Association v. FCC (290 F.3d 415), decided on May 24, 2002; the Line Sharing Orders were vacated. The court concluded that the FCC had not consi
|
https://en.wikipedia.org/wiki/Action-angle%20coordinates
|
In classical mechanics, action-angle variables are a set of canonical coordinates that are useful in characterizing the nature of commuting flows in integrable systems when the conserved energy level set is compact, and the commuting flows are complete. Action-angle variables are also important in obtaining the frequencies of oscillatory or rotational motion without solving the equations of motion. They only exist, providing a key characterization of the dynamics, when the system is completely integrable, i.e., the number of independent Poisson commuting invariants is maximal and the conserved energy surface is compact. This is usually of practical calculational value when the Hamilton–Jacobi equation is completely separable, and the separation constants can be solved for, as functions on the phase space. Action-angle variables define a foliation by invariant Lagrangian tori because the flows induced by the Poisson commuting invariants remain within their joint level sets, while the compactness of the energy level set implies they are tori. The angle variables provide coordinates on the leaves in which the commuting flows are linear.
The connection between classical Hamiltonian systems and their quantization in the Schrödinger wave mechanics approach is made clear by viewing the Hamilton-Jacobi equation as the leading order term in the WKB asymptotic series for the Schrodinger equation. In the case of integrable systems, the Bohr–Sommerfeld quantization conditions were first used,
before the advent of quantum mechanics, to compute the spectrum of the Hydrogen atom. They require that the action-angle variables exist, and that they be integral multiples of Planck's constant. Einstein's insight in the EBK quantization into the difficulty of quantizing non-integrable systems was based on this fact.
Action-angle coordinates are also useful in perturbation theory of Hamiltonian mechanics, especially in determining adiabatic invariants. One of the earliest results fro
|
https://en.wikipedia.org/wiki/Comic%20Bakery
|
Comic Bakery is a computer game for the MSX, made by Konami in 1984 and later a Commodore 64 conversion was made by Imagine Software.
Gameplay
The game is set in a bakery, where the town baker tries to bake and deliver bread (croissants in the MSX version) while fighting off raccoons. Pieces of bread move along a factory line while the raccoons try to eat the bread and switch off the machines. The player is required to keep the machinery running and also scare away the raccoons. If the player succeeds, the delivery truck is loaded with bread and drives off, advancing the player to the next level. Each level maintains the same format as the last, with the difficulty increasing as the player progresses through the levels.
Music
The music and sound effects for the C64 version were made by Martin Galway. The title chiptune has been covered by Press Play On Tape, Visa Röster, and Instant Remedy. The MSX version does not have unique music, using "Yankee Doodle" instead.
The C64 music has also been used as inspiration for the music in the games Jurassic Park (NES and Game Boy) and Platypus (PC).
References
1984 video games
Cancelled ZX Spectrum games
Commodore 64 games
Fictional chefs
Imagine Software games
Konami games
MSX games
Single-player video games
Video games about food and drink
Video games about raccoons
Video games developed in Japan
Video games scored by Martin Galway
|
https://en.wikipedia.org/wiki/ScaLAPACK
|
The ScaLAPACK (or Scalable LAPACK) library includes a subset of LAPACK routines redesigned for distributed memory MIMD parallel computers. It is currently written in a Single-Program-Multiple-Data style using explicit message passing for interprocessor communication. It assumes matrices are laid out in a two-dimensional block cyclic decomposition.
ScaLAPACK is designed for heterogeneous computing and is portable on any computer that supports MPI or PVM.
ScaLAPACK depends on PBLAS operations in the same way LAPACK depends on BLAS.
As of version 2.0 the code base directly includes PBLAS and BLACS and has dropped support for PVM.
Examples
Programming with Big Data in R fully utilizes ScaLAPACK and two-dimensional block cyclic decomposition for Big Data statistical analysis which is an extension to R.
References
External links
The ScaLAPACK Project on Netlib.org
Numerical software
|
https://en.wikipedia.org/wiki/Algebraic%20operation
|
In mathematics, a basic algebraic operation is any one of the common operations of elementary algebra, which include addition, subtraction, multiplication, division, raising to a whole number power, and taking roots (fractional power). These operations may be performed on numbers, in which case they are often called arithmetic operations. They may also be performed, in a similar way, on variables, algebraic expressions, and more generally, on elements of algebraic structures, such as groups and fields. An algebraic operation may also be defined simply as a function from a Cartesian power of a set to the same set.
The term algebraic operation may also be used for operations that may be defined by compounding basic algebraic operations, such as the dot product. In calculus and mathematical analysis, algebraic operation is also used for the operations that may be defined by purely algebraic methods. For example, exponentiation with an integer or rational exponent is an algebraic operation, but not the general exponentiation with a real or complex exponent. Also, the derivative is an operation that is not algebraic.
Notation
Multiplication symbols are usually omitted, and implied, when there is no operator between two variables or terms, or when a coefficient is used. For example, 3 × x2 is written as 3x2, and 2 × x × y is written as 2xy. Sometimes, multiplication symbols are replaced with either a dot or center-dot, so that x × y is written as either x . y or x · y. Plain text, programming languages, and calculators also use a single asterisk to represent the multiplication symbol, and it must be explicitly used; for example, 3x is written as 3 * x.
Rather than using the ambiguous division sign (÷), division is usually represented with a vinculum, a horizontal line, as in . In plain text and programming languages, a slash (also called a solidus) is used, e.g. 3 / (x + 1).
Exponents are usually formatted using superscripts, as in x2. In plain text, the TeX mark-up l
|
https://en.wikipedia.org/wiki/Programming%20language%20specification
|
In computer programming, a programming language specification (or standard or definition) is a documentation artifact that defines a programming language so that users and implementors can agree on what programs in that language mean. Specifications are typically detailed and formal, and primarily used by implementors, with users referring to them in case of ambiguity; the C++ specification is frequently cited by users, for instance, due to the complexity. Related documentation includes a programming language reference, which is intended expressly for users, and a programming language rationale, which explains why the specification is written as it is; these are typically more informal than a specification.
Standardization
Not all major programming languages have specifications, and languages can exist and be popular for decades without a specification. A language may have one or more implementations, whose behavior acts as a de facto standard, without this behavior being documented in a specification. Perl (through Perl 5) is a notable example of a language without a specification, while PHP was only specified in 2014, after being in use for 20 years. A language may be implemented and then specified, or specified and then implemented, or these may develop together, which is usual practice today. This is because implementations and specifications provide checks on each other: writing a specification requires precisely stating the behavior of an implementation, and implementation checks that a specification is possible, practical, and consistent. Writing a specification before an implementation has largely been avoided since ALGOL 68 (1968), due to unexpected difficulties in implementation when implementation is deferred. However, languages are still occasionally implemented and gain popularity without a formal specification: an implementation is essential for use, while a specification is desirable but not essential (informally, "code talks").
Forms
A programming
|
https://en.wikipedia.org/wiki/Substitution%20%28logic%29
|
A substitution is a syntactic transformation on formal expressions.
To apply a substitution to an expression means to consistently replace its variable, or placeholder, symbols with other expressions.
The resulting expression is called a substitution instance, or instance for short, of the original expression.
Propositional logic
Definition
Where ψ and φ represent formulas of propositional logic, ψ is a substitution instance of φ if and only if ψ may be obtained from φ by substituting formulas for symbols in φ, replacing each occurrence of the same symbol by an occurrence of the same formula. For example:
(R → S) & (T → S)
is a substitution instance of:
P & Q
and
(A ↔ A) ↔ (A ↔ A)
is a substitution instance of:
(A ↔ A)
In some deduction systems for propositional logic, a new expression (a proposition) may be entered on a line of a derivation if it is a substitution instance of a previous line of the derivation (Hunter 1971, p. 118). This is how new lines are introduced in some axiomatic systems. In systems that use rules of transformation, a rule may include the use of a substitution instance for the purpose of introducing certain variables into a derivation.
In first-order logic, every closed propositional formula that can be obtained from an open propositional formula φ by substitution is said to be a substitution instance of φ. If φ is a closed propositional formula we count φ itself as its only substitution instance.
Tautologies
A propositional formula is a tautology if it is true under every valuation (or interpretation) of its predicate symbols. If Φ is a tautology, and Θ is a substitution instance of Φ, then Θ is again a tautology. This fact implies the soundness of the deduction rule described in the previous section.
First-order logic
In first-order logic, a substitution is a total mapping from variables to terms; many, but not all authors additionally require σ(x) = x for all but finitely many variables x. The notation { x1 ↦ t1, …, xk ↦ t
|
https://en.wikipedia.org/wiki/Programming%20language%20implementation
|
In computer programming, a programming language implementation is a system for executing computer programs. There are two general approaches to programming language implementation:
Interpretation: The program is read as input by an interpreter, which performs the actions written in the program.
Compilation: The program is read by a compiler, which translates it into some other language, such as bytecode or machine code. The translated code may either be directly executed by hardware, or serve as input to another interpreter or another compiler.
Interpreter
An interpreter is composed of two parts: a parser and an evaluator. After a program is read as input by an interpreter, it is processed by the parser. The parser breaks the program into language components to form a parse tree. The evaluator then uses the parse tree to execute the program.
Virtual machine
A virtual machine is a special type of interpreter that interprets bytecode. Bytecode is a portable low-level code similar to machine code, though it is generally executed on a virtual machine instead of a physical machine. To improve their efficiencies, many programming languages such as Java, Python, and C# are compiled to bytecode before being interpreted.
Just-in-time compiler
Some virtual machines include a just-in-time (JIT) compiler to improve the efficiency of bytecode execution. While the bytecode is being executed by the virtual machine, if the JIT compiler determines that a portion of the bytecode will be used repeatedly, it compiles that particular portion to machine code. The JIT compiler then stores the machine code in memory so that it can be used by the virtual machine. JIT compilers try to strike a balance between longer compilation time and faster execution time.
Compiler
A compiler translates a program written in one language into another language. Most compilers are organized into three stages: a front end, an optimizer, and a back end. The front end is responsible for understanding the
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